Bunch Length Measurements With Laser/SR Cross-Correlation
Miller, Timothy; Daranciang, Dan; Lindenberg, Aaron; Corbett, Jeff; Fisher, Alan; Goodfellow, John; Huang, Xiaobiao; Mok, Walter; Safranek, James; Wen, Haidan; /SLAC
2012-07-06
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.
Measurement of the Correlation and Coherence Lengths in Boundary Layer Flight Data
NASA Technical Reports Server (NTRS)
Palumbo, Daniel L.
2011-01-01
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.
NASA Astrophysics Data System (ADS)
Bellini, Tommaso; Clark, Noel A.; Degiorgio, Vittorio; Mantegazza, Francesco; Natale, Giorgio
1998-03-01
We have studied a composite system formed by a nematic thermotropic liquid crystal in which small silica particles have been dispersed. The colloids are aggregated and exert a randomizing effect on the nematic structure. The distorted pattern of the optical axis gives rise to a strong optical turbidity τ. We have measured τ as a function of the silica concentration Φ and of the temperature T in both the isotropic and nematic phase. We have found that, at fixed T, τ has a maximum as a function of Φ, and that, upon changing Φ, the whole shape of τ(T) drastically transforms. We have devised a model to describe the scattering of light from a distorted uniaxial system. The model has been developed both in the Born approximation and in the anomalous diffraction approximation, the two regimes which cover the broad range of experimental conditions. The family of τ(T) curves experimentally obtained at different Φ's is remarkably well described by the theoretical model, using as the only fitting parameter the correlation length ζ. We have found that, upon decreasing Φ, the nematic correlation length diverges as a power law of Φ. We compare the exponent of the power law with the prediction of the Imry-Ma theory of phase behavior in disordered systems, and we discuss the connection between ζ and the fractal correlation length of the silica aggregates.
NASA Astrophysics Data System (ADS)
Kim, Jaewook; Ghim, Young-Chul; Nuclear Fusion and Plasma Lab Team
2014-10-01
A BES (beam emission spectroscopy) system and an MIR (Microwave Imaging Reflectometer) system installed in KSTAR measure 2D (radial and poloidal) density fluctuations at two different toroidal locations. This gives a possibility of measuring the parallel correlation length of ion-scale turbulence in KSTAR. Due to lack of measurement points in toroidal direction and shorter separation distance between the diagnostics compared to an expected parallel correlation length, it is necessary to confirm whether a conventional statistical method, i.e., using a cross-correlation function, is valid for measuring the parallel correlation length. For this reason, we generated synthetic 3D density fluctuation data following Gaussian random field in a toroidal coordinate system that mimic real density fluctuation data. We measure the correlation length of the synthetic data by fitting a Gaussian function to the cross-correlation function. We observe that there is disagreement between the measured and actual correlation lengths, and the degree of disagreement is a function of at least, correlation length, correlation time and advection velocity of synthetic data. We identify the cause of disagreement and propose an appropriate method to measure correct correlation length.
NASA Astrophysics Data System (ADS)
Schepanski, Kerstin; Klüser, Lars; Heinold, Bernd; Tegen, Ina
2015-12-01
Fields of dust aerosol optical depth (AOD) from numerical models and satellite observations are widely used data sets for evaluating the actual distribution of atmospheric dust aerosol. In this study we investigate the use of estimates of spatial and temporal correlation lengths (CLs) calculated from simulations using the regional model system COSMO-MUSCAT (COSMO: Consortium for Small-scale Modelling; MUSCAT: MUltiScale Chemistry Aerosol Transport Model) to characterize the spatial and temporal variability of atmospheric aerosol distribution, here mineral dust, and to provide an estimate on the temporal model output interval required in order to represent the local evolution of atmospheric dustiness. The CLs indicate the scales of variability for dust and thus provide an estimate for the stationarity of dust conditions in space and time. Additionally, CLs can be an estimate for the required resolution in time and space of observational systems to observe changes in atmospheric dust conditions that would be relevant for dust forecasts. Here, two years of dust simulations using COSMO-MUSCAT are analyzed. CLs for the individual years 2007 and 2008 are compared to the entire two-year period illustrating the impact of the length of time series on statistical analysis. The two years are chosen as they are contrasting with regard to mineral dust loads and thus provide additional information on the representativeness of the statistical analysis. Results from the COSMO-MUSCAT CL analysis are compared against CL estimates from satellite observations, here dust AOD inferred from IASI (Infrared Atmospheric Sounding Interferometer), which provides bi-daily information of atmospheric dust loading over desert land and ocean. Although CLs estimated from the satellite observations are at a generally lower level of values, the results demonstrate the applicability of daily observations for assessing the atmospheric dust distribution. Main outcomes of this study illustrate the applicability of CL for characterizing the spatio-temporal variability in atmospheric dustiness. This is in particular of interest for determining time intervals at which for example dust forecasts need to be provided. Results from this study further demonstrate that bi-daily satellite dust observations are sufficient for assessing the dust distribution over regions such as the Mediterranean region that are far from the dust sources.
Softness Correlations Across Length Scales
NASA Astrophysics Data System (ADS)
Ivancic, Robert; Shavit, Amit; Rieser, Jennifer; Schoenholz, Samuel; Cubuk, Ekin; Durian, Douglas; Liu, Andrea; Riggleman, Robert
In disordered systems, it is believed that mechanical failure begins with localized particle rearrangements. Recently, a machine learning method has been introduced to identify how likely a particle is to rearrange given its local structural environment, quantified by softness. We calculate the softness of particles in simulations of atomic Lennard-Jones mixtures, molecular Lennard-Jones oligomers, colloidal systems and granular systems. In each case, we find that the length scale characterizing spatial correlations of softness is approximately a particle diameter. These results provide a rationale for why localized rearrangements--whose size is presumably set by the scale of softness correlations--might occur in disordered systems across many length scales. Supported by DOE DE-FG02-05ER46199.
Measuring Crack Length in Coarse Grain Ceramics
NASA Technical Reports Server (NTRS)
Salem, Jonathan A.; Ghosn, Louis J.
2010-01-01
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.
Correlation between the forearm plus little finger length and the femoral length.
Naik, Monappa A; Sujir, Premjit; Tripathy, Sujit Kumar; Goyal, Tarun; Rao, Sharath K
2013-08-01
PURPOSE. To assess the correlation between the forearm plus little finger length and the femoral length in 100 volunteers. METHODS. The forearm plus little finger length and the ipsilateral femoral length of 68 male and 32 female volunteers aged 19 to 55 (mean, 35.8) years were measured using a measuring tape. The forearm plus litter finger length was measured from the tip of the olecranon to the tip of the little finger, whereas the femoral length was measured from the tip of the greater trochanter to the level of proximal pole of the patella over the outer aspect of thigh. Two observers made the measurements on 2 separate occasions. Intra- and inter-observer variations were calculated. A value of 0.75 or greater indicated excellent agreement. RESULTS. The mean forearm plus little finger length and femoral length were 39.87 (SD, 2.73) and 39.85 (SD, 2.44) cm, respectively. The mean difference between these 2 measurements was 0.028 (95% CI, -0.109 to 0.165) cm. The correlation between these 2 measurements was 0.861 (p<0.001). Patient age, sex, and body mass index did not affect this correlation. The intra- and inter-observer reliability was excellent. CONCLUSION. The forearm plus little finger length correlated with the femoral length. This method is simple, radiation-free, and can be applied in day-today practice. PMID:24014776
Measuring the Cervical Length.
Markham, Kara B; Iams, Jay D
2016-06-01
An important step toward the goal of eradicating spontaneous preterm birth was achieved with the advent of cervical sonography, a tool that advanced our knowledge of the entity of preterm parturition, improved our ability to detect women at risk for early delivery, and allowed us to prevent some of these premature births. We will describe here the correct technique for obtaining such measurements and will review the literature regarding the use of this tool in specific pregnant populations. PMID:27042799
Correlation length for interplanetary magnetic field fluctuations.
NASA Technical Reports Server (NTRS)
Fisk, L. A.; Sari, J. W.
1973-01-01
It is argued that it is necessary to consider two correlation lengths for interplanetary magnetic field fluctuations. For particles with gyroradii large enough to encounter and be scattered by large-scale tangential discontinuities in the field (particles with energies of above several GeV/nucleon) the appropriate correlation length is simply the mean spatial separation between the discontinuities. Particles with gyroradii much less than this mean separation appear to be unaffected by the discontinuities and respond only to smaller-scale field fluctuations. With this system of two correlation lengths the cosmic ray diffusion tensor may be altered from what was predicted by, for example, Jokipii and Coleman, and the objections raised recently by Klimas and Sandri to the diffusion analysis of Jokipii may apply only at relatively low energies (about 50 MeV/nucleon).
Michalewski, Janusz; Nawrocka, Zofia; Bednarski, Maciej; Nawrocki, Jerzy
2014-01-01
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
Overview of bunch length measurements.
Lumpkin, A. H.
1999-02-19
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.
Quark ensembles with the infinite correlation length
Zinov’ev, G. M.; Molodtsov, S. V.
2015-01-15
A number of exactly integrable (quark) models of quantum field theory with the infinite correlation length have been considered. It has been shown that the standard vacuum quark ensemble—Dirac sea (in the case of the space-time dimension higher than three)—is unstable because of the strong degeneracy of a state, which is due to the character of the energy distribution. When the momentum cutoff parameter tends to infinity, the distribution becomes infinitely narrow, leading to large (unlimited) fluctuations. Various vacuum ensembles—Dirac sea, neutral ensemble, color superconductor, and BCS state—have been compared. In the case of the color interaction between quarks, the BCS state has been certainly chosen as the ground state of the quark ensemble.
Telomere Length Correlations among Somatic Tissues in Adult Zebra Finches
Reichert, Sophie; Criscuolo, François; Verinaud, Elodie; Zahn, Sandrine; Massemin, Sylvie
2013-01-01
Telomeres are repetitive non coding DNA sequences located at the end of eukaryotic chromosomes, which maintain the integrity of the genome by hiding the chromosome ends from being recognised as double stranded breaks. Telomeres are emerging as biomarkers for ageing and survival, and are susceptible to reflect different individual life history trajectories. In particular, the telomere length with which one starts in life has been shown to be linked with individual life-long survival, suggesting that telomere dynamics can be a proxy for individual fitness and thereby be implicated in evolutionary trade-offs. As a consequence, an increasing number of studies were conducted on telomeres in the fields of ecology and evolutionary biology, in which telomere length was almost exclusively measured from blood samples. However, not only do the number of repeats of the telomeric sequences vary among species, but also within species with great inter-individual telomere lengths variability with age, tissues, and chromosomes. This raises the issue of the exact biological meaning of telomere measurement in blood cells and stimulated the study of the correlation of telomere lengths among tissues over age. By measuring telomere length in adult zebra finches (Taeniopygia guttata) in different somatic tissues displaying variable cell turnovers (bone marrow, brain, spleen, pectoral muscle, heart, liver and in red blood cells), we checked that the measure of telomere length in red blood cells is related to telomere lengths in the other tissues. Here we show significant relationships between the telomere lengths of red blood cells and several somatic tissues at adulthood. As red blood cells are easily accessible and suitable for the longitudinal monitoring of the individual rate of telomere loss, our study confirms that telomere length measured in red blood cells could serve as a surrogate for telomere length in the whole avian organism. PMID:24349076
Telomere length correlations among somatic tissues in adult zebra finches.
Reichert, Sophie; Criscuolo, François; Verinaud, Elodie; Zahn, Sandrine; Massemin, Sylvie
2013-01-01
Telomeres are repetitive non coding DNA sequences located at the end of eukaryotic chromosomes, which maintain the integrity of the genome by hiding the chromosome ends from being recognised as double stranded breaks. Telomeres are emerging as biomarkers for ageing and survival, and are susceptible to reflect different individual life history trajectories. In particular, the telomere length with which one starts in life has been shown to be linked with individual life-long survival, suggesting that telomere dynamics can be a proxy for individual fitness and thereby be implicated in evolutionary trade-offs. As a consequence, an increasing number of studies were conducted on telomeres in the fields of ecology and evolutionary biology, in which telomere length was almost exclusively measured from blood samples. However, not only do the number of repeats of the telomeric sequences vary among species, but also within species with great inter-individual telomere lengths variability with age, tissues, and chromosomes. This raises the issue of the exact biological meaning of telomere measurement in blood cells and stimulated the study of the correlation of telomere lengths among tissues over age. By measuring telomere length in adult zebra finches (Taeniopygia guttata) in different somatic tissues displaying variable cell turnovers (bone marrow, brain, spleen, pectoral muscle, heart, liver and in red blood cells), we checked that the measure of telomere length in red blood cells is related to telomere lengths in the other tissues. Here we show significant relationships between the telomere lengths of red blood cells and several somatic tissues at adulthood. As red blood cells are easily accessible and suitable for the longitudinal monitoring of the individual rate of telomere loss, our study confirms that telomere length measured in red blood cells could serve as a surrogate for telomere length in the whole avian organism. PMID:24349076
Chow, David; Guo, Lin; Gai, Feng; Goulian, Mark
2012-01-01
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
Slip length measurement using BBM
NASA Astrophysics Data System (ADS)
Ahmadzadegan, Adib; Snoeyink, Craig
2015-11-01
We will be presenting experimental characterizations of slip lengths of fluids in nano/micro channels. These channels are becoming increasingly important in sensor and separations applications. However, crucial questions still remain on the mechanisms that govern slip-length behavior. We used Bessel Beam microscopy (BBM), a novel super-resolution imaging system, in conjunction with TIRF system. These two, together led us to be able to do Particle Tracking Velocimetry with significantly higher accuracy than previously possible. We will be presenting results demonstrating the feasibility of this approach and advantages that make this method unique.
Correlation of residual limb length and gait parameters in amputees.
Baum, Brian S; Schnall, Barri L; Tis, John E; Lipton, Jill S
2008-07-01
There is a lack of objective data on acceptable transection levels for transfemoral amputation. We retrospectively correlated the residual limb length of 13 young, athletic transfemoral and knee disarticulation amputees with temporal-spatial, kinematic, and kinetic outcomes after gait analysis. It was hypothesised that shorter residual limb lengths would correlate with greater gait deviations. Patients' residual femoral lengths ranged from 57% to 100% of their intact femoral length. With the exception of one patient, pelvic tilt excursion was inversely related to residual limb length. Limb length did not significantly correlate with any other temporal-spatial, kinematic, or kinetic parameter investigated. Consequently, these results suggest that if the femur is at least 57% of the length of the contralateral femur, length does not dramatically alter gait. This implies that surgeons may have more flexibility to amputate at a higher level to preserve soft tissue quality and improve prosthetic fitting without sacrificing gait function. PMID:18541239
Diffusion length measurements in GaN
NASA Astrophysics Data System (ADS)
Yakimov, Eugene B.
2016-05-01
The results of diffusion length measurements by fitting the collected current dependence on electron beam energy are discussed. It is shown that in GaN structures, this method also allows measuring the local dopant concentration. A possibility of diffusion length mapping by this method is demonstrated. It is shown that the dislocation density is too low to explain the small diffusion lengths measured in n-GaN.
Clinical evaluation of five electronic root canal length measuring instruments.
Fouad, A F; Krell, K V; McKendry, D J; Koorbusch, G F; Olson, R A
1990-09-01
A previous in vitro study has shown high accuracy, but no clinically significant differences in a group of five electronic root canal length measuring instruments. The purpose of this study was to evaluate and compare the performance of the same group of instruments under clinical conditions and to correlate their accuracy to radiographic estimates of canal length. Five electronic root canal length measuring instruments were used to measure the working length to the "apex" in 20 single-rooted teeth scheduled for extraction. After extraction, the actual canal length was measured visually to a point just within the apical foramen. This length was compared with instrument length as determined electronically. The accuracy of the instruments in determining canal measurement within +/- 0.5 mm from the apical foramen varied from 55 to 75%. The differences between the instruments were not statistically significant. On average, all of the instruments except for the Endocater gave canal length measurements that were beyond the apical foramen. The variability of the measurements, which was comparable to that of estimates of canal length from preoperative radiographs, indicated that radiographic verification of the working length is still desirable. PMID:2098464
Acyl Chain Length of Phosphatidylserine Is Correlated with Plant Lifespan
Tian, Xuejun; Li, Weiqi
2014-01-01
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
Ozone Correlative Measurements Workshop
NASA Technical Reports Server (NTRS)
Hilsenrath, E. (Editor)
1985-01-01
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.
Carbon Nanotubes: Measuring Dispersion and Length
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
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.
Bunch length measurements using synchrotron ligth monitor
Ahmad, Mahmoud; Tiefenback, Michael G.
2015-09-01
The bunch length is measured at CEBAF using an invasive technique. The technique depends on applying an energy chirp for the electron bunch and imaging it through a dispersive region. The measurements are taken through Arc1 and Arc2 at CEBAF. The fundamental equations, procedure and the latest results are given.
Distance and Cable Length Measurement System
Hernández, Sergio Elias; Acosta, Leopoldo; Toledo, Jonay
2009-01-01
A simple, economic and successful design for distance and cable length detection is presented. The measurement system is based on the continuous repetition of a pulse that endlessly travels along the distance to be detected. There is a pulse repeater at both ends of the distance or cable to be measured. The endless repetition of the pulse generates a frequency that varies almost inversely with the distance to be measured. The resolution and distance or cable length range could be adjusted by varying the repetition time delay introduced at both ends and the measurement time. With this design a distance can be measured with centimeter resolution using electronic system with microsecond resolution, simplifying classical time of flight designs which require electronics with picosecond resolution. This design was also applied to position measurement. PMID:22303169
Bunch Length Measurements at JLab FEL
P. Evtushenko; J. L. Coleman; K. Jordan; J. M. Klopf; G. Neil; G. P. Williams
2006-09-01
The JLab FEL is routinely operated with sub-picosecond bunches. The short bunch length is important for high gain of the FEL. Coherent transition radiation has been used for the bunch length measurements for many years. This diagnostic can be used only in the pulsed beam mode. It is our goal to run FEL with CW beam and 74.85 MHz micropulse repetition rate. Hence it is very desirable to have the possibility of doing the bunch length measurements when running CW beam with any micropulse frequency. We use a Fourier transform infrared 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 the 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 the data obtained by the Martin-Puplett interferometer. Results of the two diagnostics are usually agree within 15%. Here we present a description of the experimental setup, data evaluation procedure and results of the beam measurements.
Correlation Length versus Gap in Frustration-Free Systems.
Gosset, David; Huang, Yichen
2016-03-01
Hastings established exponential decay of correlations for ground states of gapped quantum many-body systems. A ground state of a (geometrically) local Hamiltonian with spectral gap ε has correlation length ξ upper bounded as ξ=O(1/ε). In general this bound cannot be improved. Here we study the scaling of the correlation length as a function of the spectral gap in frustration-free local Hamiltonians, and we prove a tight bound ξ=O(1/sqrt[ε]) in this setting. This highlights a fundamental difference between frustration-free and frustrated systems near criticality. The result is obtained using an improved version of the combinatorial proof of correlation decay due to Aharonov, Arad, Vazirani, and Landau. PMID:26991196
Correlation Length versus Gap in Frustration-Free Systems
NASA Astrophysics Data System (ADS)
Gosset, David; Huang, Yichen
2016-03-01
Hastings established exponential decay of correlations for ground states of gapped quantum many-body systems. A ground state of a (geometrically) local Hamiltonian with spectral gap ɛ has correlation length ξ upper bounded as ξ =O (1 /ɛ ). In general this bound cannot be improved. Here we study the scaling of the correlation length as a function of the spectral gap in frustration-free local Hamiltonians, and we prove a tight bound ξ =O (1 /√{ɛ }) in this setting. This highlights a fundamental difference between frustration-free and frustrated systems near criticality. The result is obtained using an improved version of the combinatorial proof of correlation decay due to Aharonov, Arad, Vazirani, and Landau.
The correlation length for interplanetary magnetic field fluctuations
NASA Technical Reports Server (NTRS)
Fisk, L. A.; Sari, J. W.
1972-01-01
It is argued that it is appropriate to consider two correlation lengths for interplanetary magnetic field fluctuations. For particles with gyro-radii large enough to encounter and be scattered by large-scale tangential discontinuities in the field (particles with energies greater than or approximately equal to several GeV/nucleon) the appropriate correlation length is simply the mean spatial separation between the discontinuities, L approximately 2 x 10 to the 11th power. Particles with gyro-radii much less than this mean separation (energies less than or approximately equal to 100 MeV/nucleon) appear to be unaffected by the discontinuities and respond only to smaller-scale field fluctuations. For these particles the correlation length is shown to be L approximately 10 to the 10th power cm. With this system of two correlation lengths the cosmic-ray diffusion tensor may be altered from what was predicted by, for example, Jokipii and Coleman, and the objections raised recently by Klimas and Sandri to the diffusion analysis of Jokipii may apply only at relatively low energies (approximately 50 MeV/nucleon).
How Cells Measure Length on Subcellular Scales.
Marshall, Wallace F
2015-12-01
Cells are not just amorphous bags of enzymes, but precise and complex machines. With any machine, it is important that the parts be of the right size, yet our understanding of the mechanisms that control size of cellular structures remains at a rudimentary level in most cases. One problem with studying size control is that many cellular organelles have complex 3D structures that make their size hard to measure. Here we focus on linear structures within cells, for which the problem of size control reduces to the problem of length control. We compare and contrast potential mechanisms for length control to understand how cells solve simple geometry problems. PMID:26437596
The torque correlation length and stochastic twist dynamics of DNA
Banigan, Edward J.; Marko, John F.
2014-01-01
We introduce a short correlation length for torque in twisting-stiff biomolecules, which is necessary for the physical property that torque fluctuations be finite in amplitude. We develop a nonequilibrium theory of dynamics of DNA twisting which predicts two crossover time scales for temporal torque correlations in single-molecule experiments. Bending fluctuations can be included, and at linear order we find that they do not affect the twist dynamics. However, twist fluctuations affect bending, and we predict the spatial inhomogeneity of twist, torque, and buckling arising in nonequilibrium “rotor-bead” experiments. PMID:25019813
Torque correlation length and stochastic twist dynamics of DNA
NASA Astrophysics Data System (ADS)
Banigan, Edward J.; Marko, John F.
2014-06-01
We introduce a short correlation length for torque in twisting-stiff biomolecules, which is necessary for the physical property that torque fluctuations be finite in amplitude. We develop a nonequilibrium theory of dynamics of DNA twisting which predicts two crossover time scales for temporal torque correlations in single-molecule experiments. Bending fluctuations can be included, and at linear order we find that they do not affect the twist dynamics. However, twist fluctuations affect bending, and we predict the spatial inhomogeneity of twist, torque, and buckling arising in nonequilibrium "rotor-bead" experiments.
Torque correlation length and stochastic twist dynamics of DNA.
Banigan, Edward J; Marko, John F
2014-06-01
We introduce a short correlation length for torque in twisting-stiff biomolecules, which is necessary for the physical property that torque fluctuations be finite in amplitude. We develop a nonequilibrium theory of dynamics of DNA twisting which predicts two crossover time scales for temporal torque correlations in single-molecule experiments. Bending fluctuations can be included, and at linear order we find that they do not affect the twist dynamics. However, twist fluctuations affect bending, and we predict the spatial inhomogeneity of twist, torque, and buckling arising in nonequilibrium "rotor-bead" experiments. PMID:25019813
Unbalanced Homodyne Correlation Measurements
NASA Astrophysics Data System (ADS)
Kühn, B.; Vogel, W.
2016-04-01
A method is introduced that allows one to measure normal-ordered moments of the displaced photon-number operator up to higher orders, without the need of photon-number resolving detectors. It is based on unbalanced homodyne correlation measurements, with the local oscillator being replaced by a displaced dephased laser. The measured moments yield a simple approximation of quasiprobabilities, representing the full quantum state. Quantum properties of light are efficiently certified through normal-ordered observables directly accessible by our method, which is illustrated for a weakly squeezed vacuum and a single-photon-added thermal state.
A new ultrasonic stride length measuring system.
Maki, Hiromichi; Ogawa, Hidekuni; Yonezawa, Yoshiharu; Hahn, Allen W; Caldwell, W Morton
2012-01-01
We have developed a new ultrasonic stride length measuring system for analyzing the human gait. An ultrasonic transmitter, a radio transmitter, a pressure sensor and microcontroller are attached to the subjects heel on the right shoe and in the direction of the left shoe. Two ultrasonic receivers, a radio receiver, a microcontroller and a 1GB SD memory card are installed on the left shoe. Ultrasonic receivers are attached to the toe and heel, in the direction of the right shoe. When the right foot contacts the ground, its heel-mounted ultrasonic and radio transmitters simultaneously transmit to the left shoe. However, radio propagation velocity is far faster than ultrasonic velocity. Therefore, the radio wave acts as a start signal to the radio receiver of the left shoe, indicating the start of ultrasound transmission from the right shoe. Upon receiving the start signal, the microcontroller timer starts to measure each ultrasound propagation time from the right shoe to the left shoe. Distance between right and left shoes is calculated with the time and ultrasound velocity and stored in the SD memory card. Stride length is calculated with a cosine function, by using the obtained distances and the distance between the toe and heel of the left shoe, by a conventional computer. The stride length can then be used for many characterizations of the subjects gait. PMID:22846295
Correlative Measurements Program
NASA Technical Reports Server (NTRS)
Parsons, C. L.
1988-01-01
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.
Correlation of intraseasonal Length of Day amplitude modulation with ENSO.
NASA Astrophysics Data System (ADS)
Zhong, Min; Zhu, Yaozhong; Gao, Buxi
1999-02-01
The Hilbert transform is used to extract the amplitude modulation signals for the intraseasonal variation of Length of Day ranging from 1962 to 1996. The results reveal that the intraseasonal Length of Day amplitude modulation variation has not only a positive secular trend, but also an interannual variation which is ahead of the ENSO evolution. The amplitude modulations for the about 50-day oscillation and the about 120-day oscillation have been studied separately. This shows that the peaks of the approximately 50-day oscillation amplitude modulation always occur longer than one year before the appearance of each ENSO event. They also indicate the dominant correspondence between the about 120-day oscillation amplitude modulation and ENSO events since 1976 and the absolutely negative correlation with ENSO before 1972 because of phase change of 180 degrees in the evolution of the about 120-day oscillation amplitude modulation time series at the beginning of the 1970's.
Bunch Length Measurements using Coherent Radiation
Ischebeck, Rasmus; Barnes, Christopher; Blumenfeld, Ian; Decker, Franz-Josef; Hogan, Mark; Iverson, Richard H.; Krejcik, Patrick; Siemann, Robert H.; Walz, Dieter; Kirby, Neil; Clayton, Chris; Huang, Chengkun; Johnson, Devon K.; Lu, Wei; Marsh, Ken; Deng, Suzhi; Oz, Erdem; /Southern California U.
2005-06-24
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.
Cross correlation flow measurement
Kufta, R.J.
1997-12-31
Many methods of flow measurement require direct contact with the hot dirty gases, resulting in high maintenance costs and potential unreliability. The CODEL Model 502 Flow Monitors utilize an infra-red cross-correlation technique which requires no contact with the flue gases. The method resembles flow measurement with chemical dye or radio-active tracers, where the velocity is derived from the transport time of the tracer between two measuring points a known distance apart. However, instead of an artificial tracer being added, the naturally occurring fluctuations of the infra-red energy in the gas stream are used as the tracer. Fully purged transducers with no moving components make the system highly reliable and minimize maintenance requirements. The instrument is ideally suited to monitoring the flow rate of hot, dirty gases.
Material Effects and Detector Response Corrections for Bunch Length Measurements
Zacherl, W.; Blumenfeld, I.; Berry, M.; Decker, F.-J.; Hogan, M.J.; Ischebeck, R.; Iverson, R.; Kirby, N.; Siemann, R.; Walz, D.; Clayton, C.E.; Huang, C.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.B.; Zhou, M.; Katsouleas, T.C.; Muggli, P.; Oz, E.; /Southern California U.
2007-06-28
A typical diagnostic used to determine the bunch length of ultra-short electron bunches is the auto-correlation of coherent transition radiation. This technique can produce artificially short bunch length results due to the attenuation of low frequency radiation if corrections for the material properties of the Michelson interferometer and detector response are not made. Measurements were taken using FTIR spectroscopy to determine the absorption spectrum of various materials and the response of a Molectron P1-45 pyroelectric detector. The material absorption data will be presented and limitations on the detector calibration discussed.
Cross correlation and length scales in turbulent flows near surfaces
NASA Technical Reports Server (NTRS)
Hunt, J. C. R.; Moin, P.; Lee, M.; Moser, R. D.; Spalart, P.; Mansour, N. N.; Kaimal, J. C.; Gaynor, E.
1989-01-01
Two kinds of length scales are used in turbulent flows; 'functional length scales' such as mixing length, dissipation length L(sub epsilon), etc., and 'flow-field length scales' derived from cross correlations of velocity, pressure, etc. in the flow. Some connection between these scales are derived here. We first consider the cross correlation R(sub vv)(y,y(sub 1)) of the normal components u at two heights y, y(sub 1) above a rigid surface, normalized by the velocity y(sub 1) (greater than y). For shear-free boundary layers it is found theoretically, and in field and numerical experiments that R(sub vv) approximately equals y/y(sub 1). For shear layers it is also found that R(sub vv) approximately equals f(y/y(sub 1)) less than or equal to y,y(sub 1). This function f differs slightly between low Reynolds number numerical simulations and field experiments. The lateral structure defined by R(sub vv)(y,r(sub 3); y(sub 1),0) is also self similar and shows that the eddies centered at about y(sub 1) appear to have constant lateral width a(sub 3) above and below y(sub 1), where a(sub 3, sup +) approximately equals 7+1/(1.4dU(sup +)/dy(sup +)), when normalized on u(sub *) and v, where U is the mean velocity. Results for L(sub epsilon, sup -1) from direct numerical simulation are found to compare well with the formula L(sub epsilon, sup -1) = A(sub B)/y + A(sub S)dU/dy/v, for unidirectional and reversing turbulent boundary layers and channel flow, except near where dU/dy approximately equals 0. The conclusion is that the large-scale eddy structure and length scales in these flows are determined by a combination of shear and blocking, and that the vertical component of turbulence has a self-similar structure in both kinds of boundary layer.
Local-hybrid functional based on the correlation length
Johnson, Erin R.
2014-09-28
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.
Standardisation of crown-rump length measurement.
Ioannou, C; Sarris, I; Hoch, L; Salomon, L J; Papageorghiou, A T
2013-09-01
Correct estimation of gestational age is essential for any study of ultrasound biometry and for everyday clinical practice. However, inconsistency in pregnancy dating may occur through differences in measurement methods or errors during measurement. In the INTERGROWTH-21(st) Project, pregnancies are dated by the last menstrual period, provided that it is certain and associated with a regular menstrual cycle, and the gestational age by dates concurs with a first-trimester ultrasound crown-rump length (CRL) estimation. Hence, there was a need to standardise CRL measurement methodology across the study sites in this international, multicentre project to avoid systematic differences in dating. To achieve uniformity we undertook the following steps: the ultrasound technique was standardised by disseminating an illustrated, operating manual describing CRL plane landmarks and calliper application, and posters describing the correct acquisition technique were disseminated for quick reference. To ensure that all ultrasonographers understood the methodology, they forwarded a log-book to the INTERGROWTH-21(st) Ultrasound Coordinating Unit, containing the answers to a written test on the manual material and five images of a correctly acquired CRL. Interpretation of CRL was also standardised by ensuring that the same CRL regression formula was used across all study sites. These methods should minimise potential systematic errors in dating associated with pooling data from different health institutions, and represent a model for standardising CRL measurement in future studies. PMID:23678951
Mask roughness induced LER: geometric model at long correlation lengths
McClinton, Brittany M.; Naulleau, Patrick P.
2011-02-11
Collective understanding of how both the resist and line-edge roughness (LER) on the mask affect the final printed LER has made significant advances. What is poorly understood, however, is the extent to which mask surface roughness couples to image plane LER as a function of illumination conditions, NA, and defocus. Recently, progress has been made in formulating a simplified solution for mask roughness induced LER. Here, we investigate the LER behavior at long correlation lengths of surface roughness on the mask. We find that for correlation lengths greater than 3/NA in wafer dimensions and CDs greater than approximately 0.75/NA, the previously described simplified model, which remains based on physical optics, converges to a 'geometric regime' which is based on ray optics and is independent of partial coherence. In this 'geometric regime', the LER is proportional to the mask slope error as it propagates through focus, and provides a faster alternative to calculating LER in contrast to either full 2D aerial image simulation modeling or the newly proposed physical optics model. Data is presented for both an NA = 0.32 and an NA = 0.5 imaging system for CDs of 22-nm and 50-nm horizontal-line-dense structures.
Length of adaptive walk on uncorrelated and correlated fitness landscapes
NASA Astrophysics Data System (ADS)
Seetharaman, Sarada; Jain, Kavita
2014-09-01
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.
Relating Vegetation Aerodynamic Roughness Length to Interferometric SAR Measurements
NASA Technical Reports Server (NTRS)
Saatchi, Sassan; Rodriquez, Ernesto
1998-01-01
In this paper, we investigate the feasibility of estimating aerodynamic roughness parameter from interferometric SAR (INSAR) measurements. The relation between the interferometric correlation and the rms height of the surface is presented analytically. Model simulations performed over realistic canopy parameters obtained from field measurements in boreal forest environment demonstrate the capability of the INSAR measurements for estimating and mapping surface roughness lengths over forests and/or other vegetation types. The procedure for estimating this parameter over boreal forests using the INSAR data is discussed and the possibility of extending the methodology over tropical forests is examined.
Toure, Ally Mounirou; Goïta, Kalifa; Royer, Alain; Mätzler, Christian; Schneebeli, Martin
2008-12-20
The study is based on experimental work conducted in alpine snow. We made microwave radiometric and near-infrared reflectance measurements of snow slabs under different experimental conditions. We used an empirical relation to link near-infrared reflectance of snow to the specific surface area (SSA), and converted the SSA into the correlation length. From the measurements of snow radiances at 21 and 35 GHz, we derived the microwave scattering coefficient by inverting two coupled radiative transfer models (the sandwich and six-flux model). The correlation lengths found are in the same range as those determined in the literature using cold laboratory work. The technique shows great potential in the determination of the snow correlation length under field conditions. PMID:19104524
Automatic detection and measurement of femur length from fetal ultrasonography
NASA Astrophysics Data System (ADS)
Mukherjee, Prateep; Swamy, Gokul; Gupta, Madhumita; Patil, Uday; Krishnan, Kajoli Banerjee
2010-03-01
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.
In-vitro correlation between tension and length change in an anterior cruciate ligament substitute.
Good, L
1995-06-01
The length change and tension patterns from multiple insertion locations of an anterior cruciate ligament substitute were studied in 10 cadaver knees. Length change was measured with a spring-loaded isometer of low stiffness, and tension was measured with a piezoelectric load cell. In both instances a thin Kevlar test ligament was positioned in five different femoral and two different tibial ligament insertion locations, that were all located within the normal attachments of the anterior cruciate ligament. Differences were found regarding length changes and tension patterns from a simulated active extension between the central, posterior, and anterior femoral locations. All locations showed larger length change and tension values in extension than in flexion. The anterior femoral ligament insertion location showed length change and tension patterns with increasing values in flexion compared to the other femoral locations. The anterior tibial ligament insertion location showed smaller excursions of both length and tension, than did the central one, but the patterns of the curves were similar. A statistically significant correlation was found between length change and tension patterns throughout a 130-0 degrees range of motion. A statistically significant correlation was also found between the maximum length and tension values. No fixed relationship was found between the magnitude of the length and tension values, when different intervals of the range of motion were studied. RELEVANCE: The intraoperative employment of length change measurements of a test ligament in anterior cruciate ligament reconstruction gives information on where high tension can be expected in the range of motion of the knee, and how this can differ depending on the angle of graft fixation. The information gained can also be used to improve drill channel location. However, no predictions on the magnitude of tension can be made, mainly due to large biological variability. PMID:11415553
Direct measure of quantum correlation
Yu, Chang-shui; Zhao, Haiqing
2011-12-15
The quantumness of the correlation known as quantum correlation is usually measured by quantum discord. So far various quantum discords can be roughly understood as indirect measure by some special discrepancy of two quantities. We present a direct measure of quantum correlation by revealing the difference between the structures of classically and quantum correlated states. Our measure explicitly includes the contributions of the inseparability and local nonorthogonality of the eigenvectors of a density matrix. Besides its relatively easy computability, our measure can provide a unified understanding of quantum correlation of all the present versions.
Coding Ropes For Length And Speed Measurements
NASA Technical Reports Server (NTRS)
Rupp, Charles C.; Tiesenhausen, Georg Von
1988-01-01
Ferromagnetic staples serve as markers. Like crude magnetic-tape-playback head, sensor detects ferromagnetic staples as rope is unwound or wound. Pulses from staples analyzed electronically; numbers of pulses and intervals between them interpreted in terms of velocity of rope and length payed out. Adaptable to laying submarine cables and contstruction of suspension bridges.
Dynamic Correlation Length Scales under Isochronal Conditions at High Pressures
NASA Astrophysics Data System (ADS)
Casalini, Riccardo
2015-03-01
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.
Ultrasound Accuracy of Liver Length Measurement with Cadaveric Specimens
Riestra-Candelaria, Bárbara L.; Rodríguez-Mojica, Wilma; Vázquez-Quiñones, Luis E.; Jorge, Juan Carlos
2016-01-01
The liver is one of the principal organs of our body involved in over 500 physiological functions related to metabolism, digestion, immunity, and storage of nutrients, which makes it an essential organ to preserve life. Given that there are a number of approaches to measure liver length through diagnostic 2D sonography, this work aims to determine the most accurate measurement of this organ. Cadaveric specimens (n = 21) were employed to assess measurements in midclavicular line (MCL) and midaxillary line (MAL). Each measurement was calculated in anteroposterior (AP) and craniocaudal (CC) planes. In addition, in situ measurements were obtained by accessing the organ through the anterior thoracoabdominal wall. Statistical differences were detected between MCL and MAL measurements (p < 0.05), a positive correlation between MAL CC and in situ anterior measurements were noted (r = 0.97). Liver size, as assessed through in situ measurements, varied as a funtion of BMI and waist circumference (p < 0.05). It is concluded that CC measurement of the RLL in MAL from the uppermost right hemi-diaphragm to the inferior tip of the right lobe through a horizontal line parallel to the anterior liver wall is the most accurate measurement of the organ by sonography. PMID:26966729
Measurements of Newton's gravitational constant and the length of day
NASA Astrophysics Data System (ADS)
Anderson, J. D.; Schubert, G.; Trimble, V.; Feldman, M. R.
2015-04-01
About a dozen measurements of Newton's gravitational constant, G, since 1962 have yielded values that differ by far more than their reported random plus systematic errors. We find that these values for G are oscillatory in nature, with a period of P = 5.899 +/- 0.062 \\text{yr} , an amplitude of (1.619 +/- 0.103) × 10-14 \\text{m}3 \\text{kg}-1 \\text{s}-2 , and mean-value crossings in 1994 and 1997. However, we do not suggest that G is actually varying by this much, this quickly, but instead that something in the measurement process varies. Of other recently reported results, to the best of our knowledge, the only measurement with the same period and phase is the Length of Day (LOD —defined as a frequency measurement such that a positive increase in LOD values means slower Earth rotation rates and therefore longer days). The aforementioned period is also about half of a solar activity cycle, but the correlation is far less convincing. The 5.9 year periodic signal in LOD has previously been interpreted as due to fluid core motions and inner-core coupling. We report the G/LOD correlation, whose statistical significance is 0.99764 assuming no difference in phase, without claiming to have any satisfactory explanation for it. Least unlikely, perhaps, are currents in the Earth's fluid core that change both its moment of inertia (affecting LOD) and the circumstances in which the Earth-based experiments measure G. In this case, there might be correlations with terrestrial-magnetic-field measurements.
Interferometric measurement of the axial length of the eye
NASA Astrophysics Data System (ADS)
Hard, Sverker; Fuxin, Per-Ola; Gerhardsson, Dan; Torstensson, Per-Arne; Nilsson, Tomas; Sjostrand, Johan
1999-02-01
A fast and accurate fiberoptic-based interferometer for non- contact measurements of the axial length of the eye was constructed and tested. A novelty of the interferometer design is the use of a diffractive, bifocal lens, which simultaneously focuses on the cornea and on the retina. A superluminescent light emitting diode with a coherence length of 30 micrometers is used as light source. The axial length of the eye is measured by rapidly translating a reference mirror a distance covering the axial length. The estimated accuracy of a measurement is about 100 micrometer, a number which compares well with those of conventional ultrasonic-based measurements.
50 CFR Appendix C to Part 622 - Fish Length Measurements
Code of Federal Regulations, 2010 CFR
2010-10-01
... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Fish Length Measurements C Appendix C to... ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF, AND SOUTH ATLANTIC Pt. 622, App. C Appendix C to Part 622—Fish Length Measurements ER03JY96.000 Figure 1 of Appendix C to Part...
50 CFR Appendix C to Part 622 - Fish Length Measurements
Code of Federal Regulations, 2013 CFR
2013-10-01
... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Fish Length Measurements C Appendix C to Part 622 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC..., App. C Appendix C to Part 622—Fish Length Measurements ER17AP13.000 ER17AP13.001...
50 CFR Appendix C to Part 622 - Fish Length Measurements
Code of Federal Regulations, 2011 CFR
2011-10-01
... 50 Wildlife and Fisheries 10 2011-10-01 2011-10-01 false Fish Length Measurements C Appendix C to... ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF, AND SOUTH ATLANTIC Pt. 622, App. C Appendix C to Part 622—Fish Length Measurements ER03JY96.000 Figure 1 of Appendix C to Part...
50 CFR Appendix C to Part 622 - Fish Length Measurements
Code of Federal Regulations, 2012 CFR
2012-10-01
... 50 Wildlife and Fisheries 12 2012-10-01 2012-10-01 false Fish Length Measurements C Appendix C to Part 622 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Appendix C to Part 622—Fish Length Measurements ER03JY96.000 Figure 1 of Appendix C to Part...
50 CFR Appendix C to Part 622 - Fish Length Measurements
Code of Federal Regulations, 2014 CFR
2014-10-01
... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Fish Length Measurements C Appendix C to Part 622 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC..., App. C Appendix C to Part 622—Fish Length Measurements ER17AP13.000 ER17AP13.001...
From Concrete to Abstract in the Measurement of Length
NASA Astrophysics Data System (ADS)
Stephanou, Andreas; Fisher, William P., Jr.
2013-09-01
The concatenation of units of length is widely viewed as the paradigmatic expression of fundamental measurement. Survey, assessment, and test scores in educational and psychological measurement are often interpreted in ways that assume a concatenation of units to have been established, even though these assumptions are rarely stated or tested. A concatenation model for measurement is shown to be equivalent to a Rasch model: any two units of measurement placed end to end must together be of the same length as either one of them added to itself. This additive principle and a concatenation model of measurement together serve as a heuristic guide for organizing two experimental approaches to calibrating instruments for measuring length. The capacity to reproduce the unit of measurement from theory with no need for repeated empirical calibration experiments, as in the geometrical bisection of the line and the resultant halving of the length measure, is highlighted as essential to demonstrating a thorough understanding of the construct.
Foot length--a new and potentially useful measurement in the neonate.
James, D K; Dryburgh, E H; Chiswick, M L
1979-03-01
The foot length, occipito-frontal head circumference (OFC), crown-rump, and crown-heel length (CHL) of 123 neonates of gestational ages 26-42 weeks, were measured between 12 hours and 5 days. A gauge, designed and constructed at St Mary's Hospital, Manchester, was used to measure foot length. In term babies (37-42 weeks) who were of weights appropriate for gestational age (AGA) the scatter about the mean of foot length measurements was small (coefficient of variation = 4.5%) compared with birthweight (coefficient of variation = 12.0%). The wide range of foot length measurements in babies of different gestational ages prevented maturity being accurately estimated. The mean birthweight of term light-for-dates (LFD) babies was 30.9% lower than term AGA babies, whereas the mean foot length, OFC, and body length of LFD babies was reduced by only 4.2-8.8%. There was a positive linear correlation between foot length and other indices of body size in LFD and AGA babies of all gestational ages. However, in premature babies (less than 37 weeks) the correlation between foot length and birthweight (r = 0.95) and foot length and CHL (r = 0.96) was pronounced. The 95% confidence limits of the regression lines were +/- 327 g and +/- 2.3 cm respectively. Birthweight and CHL of premature babies can therefore be estimated from a measurement of foot length that is performed simply and rapidly. Measurements of foot length are valuable in premature babies who are too ill at birth for conventional anthropometric measurements to be made, and in whom such measurements cannot be carried out subsequently because of the encumbrance of the incubator and intensive care apparatus. Drug dosages and intravenous fluid requirements based on body weight or surface area can be indirectly calculated from a measurement of foot length. PMID:434910
Foot length--a new and potentially useful measurement in the neonate.
James, D K; Dryburgh, E H; Chiswick, M L
1979-01-01
The foot length, occipito-frontal head circumference (OFC), crown-rump, and crown-heel length (CHL) of 123 neonates of gestational ages 26-42 weeks, were measured between 12 hours and 5 days. A gauge, designed and constructed at St Mary's Hospital, Manchester, was used to measure foot length. In term babies (37-42 weeks) who were of weights appropriate for gestational age (AGA) the scatter about the mean of foot length measurements was small (coefficient of variation = 4.5%) compared with birthweight (coefficient of variation = 12.0%). The wide range of foot length measurements in babies of different gestational ages prevented maturity being accurately estimated. The mean birthweight of term light-for-dates (LFD) babies was 30.9% lower than term AGA babies, whereas the mean foot length, OFC, and body length of LFD babies was reduced by only 4.2-8.8%. There was a positive linear correlation between foot length and other indices of body size in LFD and AGA babies of all gestational ages. However, in premature babies (less than 37 weeks) the correlation between foot length and birthweight (r = 0.95) and foot length and CHL (r = 0.96) was pronounced. The 95% confidence limits of the regression lines were +/- 327 g and +/- 2.3 cm respectively. Birthweight and CHL of premature babies can therefore be estimated from a measurement of foot length that is performed simply and rapidly. Measurements of foot length are valuable in premature babies who are too ill at birth for conventional anthropometric measurements to be made, and in whom such measurements cannot be carried out subsequently because of the encumbrance of the incubator and intensive care apparatus. Drug dosages and intravenous fluid requirements based on body weight or surface area can be indirectly calculated from a measurement of foot length. Images Fig. 1 Fig. 2 PMID:434910
NASA Astrophysics Data System (ADS)
Carpentier, S. F. A.; Roy-Chowdhury, K.; Hurich, C. A.
2011-07-01
A novel statistical technique has been applied to the AG-48 seismic line from the LITHOPROBE dataset, passing through the Abitibi-Grenville Province, Canada. The method maps lateral stochastic parameters, representing von Karman heterogeneity distributions in the crust, estimated from migrated deep reflection data. Together with these parameters, viz. lateral correlation length and power-law exponent, we also compute their associated maximum-likelihood uncertainties. Combining normalised measurements of lateral correlation and their uncertainties, objective profiles of crustal fabric can be made. These profiles indicate significant spatial variations in macro-scale petrofabric. Correlation length, which carries useful information about structural scale lengths of heterogeneous bodies, is an especially robust parameter with moderate associated uncertainties. Although the general outline of the profiles conforms to the earlier tectonic interpretations (based on line-drawings), new features are visible too. The macro-scale petrofabric is seen to vary significantly within the tectonic terrains identified earlier — in depth as well as laterally. A consequence of this additional delineation is that we can explain an existing part of the AG-48 line equally well in terms of collisional deformation and in terms of the effects of a major shear zone projected onto a parallel segment of the line.
Correlation between length and tilt of lipid tails.
Kopelevich, Dmitry I; Nagle, John F
2015-10-21
It is becoming recognized from simulations, and to a lesser extent from experiment, that the classical Helfrich-Canham membrane continuum mechanics model can be fruitfully enriched by the inclusion of molecular tilt, even in the fluid, chain disordered, biologically relevant phase of lipid bilayers. Enriched continuum theories then add a tilt modulus κθ to accompany the well recognized bending modulus κ. Different enrichment theories largely agree for many properties, but it has been noticed that there is considerable disagreement in one prediction; one theory postulates that the average length of the hydrocarbon chain tails increases strongly with increasing tilt and another predicts no increase. Our analysis of an all-atom simulation favors the latter theory, but it also shows that the overall tail length decreases slightly with increasing tilt. We show that this deviation from continuum theory can be reconciled by consideration of the average shape of the tails, which is a descriptor not obviously includable in continuum theory. PMID:26493917
Time correlators from deferred measurements
NASA Astrophysics Data System (ADS)
Oehri, D.; Lebedev, A. V.; Lesovik, G. B.; Blatter, G.
2016-01-01
Repeated measurements that typically occur in two-time or multitime correlators rely on von Neumann's projection postulate, telling how to restart the system after an intermediate measurement. We invoke the principle of deferred measurement to describe an alternative procedure in which coevolving quantum memories extract system information through entanglement, combined with a final readout of the memories described by Born's rule. Our approach to repeated quantum measurements respects the unitary evolution of quantum mechanics during intermediate times, unifies the treatment of strong and weak measurements, and reproduces the projected and (anti)symmetrized correlators in the two limits. As an illustration, we apply our formalism to the calculation of the electron charge correlator in a mesoscopic physics setting, where single electron pulses assume the role of flying memory qubits. We propose an experimental setup that reduces the measurement of the time correlator to the measurement of currents and noise, exploiting the (pulsed) injection of electrons to cope with the challenge of performing short-time measurements.
Can Transabdominal Cervical Length Measurement Exclude Short Cervix?
Rhoades, Janine S; Park, Jennifer M; Stout, Molly J; Macones, George A; Cahill, Alison G; Tuuli, Methodius G
2016-04-01
Objective This study aims to determine if transabdominal (TA) cervical length may be used to rule out a short cervix on transvaginal (TV) ultrasound. Study Design We conducted a prospective cohort study of women undergoing routine anatomic survey at 17 to 23 weeks gestation. TA and TV cervical length measurements were obtained in each patient. A short cervix was defined as TV cervical length < 30 mm. Predictive characteristics were calculated for different cutoff values of TA cervical length. Results There were 404 patients enrolled, a TA cervical length could not be obtained in 83 women (20.6%) and 318 women had both TA and TV measurements. Of those, 14 (4.4%) had a TV cervical length < 30 mm. TA cervical length measurement ≥ 35 mm excluded the possibility of TV cervical length < 30 mm (negative predictive value, 99.5%; 95% confidence interval [CI], 97.4; 100%). In our cohort, 67.6% (95% CI, 62.2; 72.7%) of TV ultrasounds could have been avoided using a TA cervical length cutoff of ≥ 35 mm. Conclusion ATA cervical length of at least 35 mm excludes a short cervix of < 30 mm. While TA cervical length screening may not be feasible in 1 in 5 women, it may be used to decrease the burden of universal TV cervical length screening. PMID:26523740
Correlation Length of X-ray Brightest Abell Clusters
NASA Astrophysics Data System (ADS)
Muriel, H.; Abadi, M. G.; Lambas, D. G.
1998-12-01
We compute the cluster auto-correlation function xicc(r) of an X-ray flux limited sample of Abell clusters (XBACs, {ebe}). For the total XBACs sample we find a power-law fit xicc = (r/r_0)gamma with r_0 = 21.1 Mpc h^{-1}and gamma = -1.9 consistent with the results of R >= 1 Abell clusters. We also analyze xicc(r) for subsamples defined by different X-ray luminosity thresholds where we find a weak tendency of larger values of r_0 with increasing X-ray luminosity although with a low statistical significance. In the different subsamples analyzed we find 21 < r_0 < 35 Mpc h^{-1} and -1.9 < gamma < -1.6. Our analysis suggests that cluster X-ray luminosities may be used for a reliable confrontation of cluster spatial distribution properties in models and observations.
Measuring the Length of a Captured Burmese Python
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. ...
Automated Defect and Correlation Length Analysis of Block Copolymer Thin Film Nanopatterns
Murphy, Jeffrey N.; Harris, Kenneth D.; Buriak, Jillian M.
2015-01-01
Line patterns produced by lamellae- and cylinder-forming block copolymer (BCP) thin films are of widespread interest for their potential to enable nanoscale patterning over large areas. In order for such patterning methods to effectively integrate with current technologies, the resulting patterns need to have low defect densities, and be produced in a short timescale. To understand whether a given polymer or annealing method might potentially meet such challenges, it is necessary to examine the evolution of defects. Unfortunately, few tools are readily available to researchers, particularly those engaged in the synthesis and design of new polymeric systems with the potential for patterning, to measure defects in such line patterns. To this end, we present an image analysis tool, which we have developed and made available, to measure the characteristics of such patterns in an automated fashion. Additionally we apply the tool to six cylinder-forming polystyrene-block-poly(2-vinylpyridine) polymers thermally annealed to explore the relationship between the size of each polymer and measured characteristics including line period, line-width, defect density, line-edge roughness (LER), line-width roughness (LWR), and correlation length. Finally, we explore the line-edge roughness, line-width roughness, defect density, and correlation length as a function of the image area sampled to determine each in a more rigorous fashion. PMID:26207990
Fiber Length Measurement In Pulp And Paper Industry
NASA Astrophysics Data System (ADS)
Piirainen, Raili A.
1986-10-01
For the pulp and paper maker, product quality and production costs are the major factors that determine profitability. Quality has to be high enough to satisfy the customer and costs low enough to maintain competitiveness. Accurate and readily available fiber length information is fast becoming one of the most important control factors to achieve these targets. Measurement of fiber length has been difficult and time consuming in the past --- appli-cation to production almost impossible due to the historical nature of the data. The Kajaani fiber length analyzer has revolutionized fiber length analysis. Even more accurate than the microscopic method and infinitely faster than mechanical classifiers, such as Bauer McNett or Clark classifiers, the Kajaani analyzer opens new horizons for the paper maker. The Kajaani method is an optical method and is based on the ability of fibers to change the direction of light polarization. With no critical sample preparation, the results are ready in a few minutes. During this time, the analyzer counts and measures over 3000 individual fibers. Results are printed out either in graphic or numerical form. Some of the typical applications of the Kajaani fiber length analyzer are to determine hardwood/softwood ratios in pulp and paper mills both in brownstock and stock preparation areas, to predict strength properties of mechanical pulp based on the fiber length information, to measure the coarseness of the fibers, to evaluate screening and refining processes and to check the quality of purchased pulp.
Measurement of Trap Length for an Optical Trap
NASA Technical Reports Server (NTRS)
Wrbanek, Susan Y.
2009-01-01
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.
Driscoll, J.F.; Huh, H.; Yoon, Y.; Donbar, J.
1996-10-01
Measurements of flame length are reported that help to quantify the overall fuel-air mixing process that occurs within a jet-like flame in the supersonic regime. A nonpremixed, turbulent, hydrogen-air jet flame is stabilized along the axis of a Mach 2.2 coflowing air stream. Supersonic flame lengths are compared to measured lengths of subsonic hydrogen-air flames with coflow that were stabilized on the axis of a subsonic wind tunnel for a range of fuel/air velocity and density ratios. The supersonic flames are found to be significantly shorter than (i.e., typically half as long as) corresponding subsonic flames,providing that both the velocity and density ratios are matched for the two cases. This difference implies that for axisymmetric jet geometries with combustion, mixing rates are larger in the supersonic case. Compressibility effects are not believed to be significant since typical convective Mach numbers are less than 0.45. One possible reason why the supersonic flames are relatively short is that the radial velocity, which controls entrainment, can be altered by compression/expansion waves that are inherent to the jet geometry. Both subsonic and supersonic flame lengths increase as the normalized fuel mass flux increases, which is predicted to occur by a scaling analysis. The density of the supersonic airstream was decreased in order to simulate an increase in altitude, and the supersonic flames became longer, as predicted by the analysis. Increasing the air stagnation temperature to 600 K shortens the supersonic flames, which is not explained by the mixing-limited scaling analysis and may be due to finite-rate chemistry or partially premixed combustion, both of which are temperature dependent processes.
What can we learn about a dynamical length scale in glasses from measurements of surface mobility?
NASA Astrophysics Data System (ADS)
Forrest, J. A.
2013-08-01
We consider the ability of recent measurements on the size of a liquid-like mobile surface region in glasses to provide direct information on the length scale of enhanced surface mobility. While these quantities are strongly related there are important distinctions that limit the ability of measurements to quantify the actual length over which the surface properties change from surface to bulk-like. In particular, we show that for temperatures near the bulk glass transition, measurements of a liquid-like mobile layer may have very limited predictive power when it comes to determining the temperature dependent length scale of enhanced surface mobility near the glass transition temperature. This places important limitations on the ability of measurements of such enhanced surface dynamics to contribute to discussion on the length scale for dynamical correlation in glassy materials.
Ludington, William B.; Ishikawa, Hiroaki; Serebrenik, Yevgeniy V.; Ritter, Alex; Hernandez-Lopez, Rogelio A.; Gunzenhauser, Julia; Kannegaard, Elisa; Marshall, Wallace F.
2015-01-01
Cells control organelle size with great precision and accuracy to maintain optimal physiology, but the mechanisms by which they do so are largely unknown. Cilia and flagella are simple organelles in which a single measurement, length, can represent size. Maintenance of flagellar length requires an active transport process known as intraflagellar transport, and previous measurements suggest that a length-dependent feedback regulates intraflagellar transport. But the question remains: how is a length-dependent signal produced to regulate intraflagellar transport appropriately? Several conceptual models have been suggested, but testing these models quantitatively requires that they be cast in mathematical form. Here, we derive a set of mathematical models that represent the main broad classes of hypothetical size-control mechanisms currently under consideration. We use these models to predict the relation between length and intraflagellar transport, and then compare the predicted relations for each model with experimental data. We find that three models—an initial bolus formation model, an ion current model, and a diffusion-based model—show particularly good agreement with available experimental data. The initial bolus and ion current models give mathematically equivalent predictions for length control, but fluorescence recovery after photobleaching experiments rule out the initial bolus model, suggesting that either the ion current model or a diffusion-based model is more likely correct. The general biophysical principles of the ion current and diffusion-based models presented here to measure cilia and flagellar length can be generalized to measure any membrane-bound organelle volume, such as the nucleus and endoplasmic reticulum. PMID:25809250
Ludington, William B; Ishikawa, Hiroaki; Serebrenik, Yevgeniy V; Ritter, Alex; Hernandez-Lopez, Rogelio A; Gunzenhauser, Julia; Kannegaard, Elisa; Marshall, Wallace F
2015-03-24
Cells control organelle size with great precision and accuracy to maintain optimal physiology, but the mechanisms by which they do so are largely unknown. Cilia and flagella are simple organelles in which a single measurement, length, can represent size. Maintenance of flagellar length requires an active transport process known as intraflagellar transport, and previous measurements suggest that a length-dependent feedback regulates intraflagellar transport. But the question remains: how is a length-dependent signal produced to regulate intraflagellar transport appropriately? Several conceptual models have been suggested, but testing these models quantitatively requires that they be cast in mathematical form. Here, we derive a set of mathematical models that represent the main broad classes of hypothetical size-control mechanisms currently under consideration. We use these models to predict the relation between length and intraflagellar transport, and then compare the predicted relations for each model with experimental data. We find that three models-an initial bolus formation model, an ion current model, and a diffusion-based model-show particularly good agreement with available experimental data. The initial bolus and ion current models give mathematically equivalent predictions for length control, but fluorescence recovery after photobleaching experiments rule out the initial bolus model, suggesting that either the ion current model or a diffusion-based model is more likely correct. The general biophysical principles of the ion current and diffusion-based models presented here to measure cilia and flagellar length can be generalized to measure any membrane-bound organelle volume, such as the nucleus and endoplasmic reticulum. PMID:25809250
Flores-Mir, Carlos; Rosenblatt, Mark R; Major, Paul W.; Carey, Jason P.; Heo, Giseon
2014-01-01
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%. PMID:25715716
Determination of ?? scattering lengths from measurement of ?? atom lifetime
NASA Astrophysics Data System (ADS)
Adeva, B.; Afanasyev, L.; Benayoun, M.; Benelli, A.; Berka, Z.; Brekhovskikh, V.; Caragheorgheopol, G.; Cechak, T.; Chiba, M.; Chliapnikov, P. V.; Ciocarlan, C.; Constantinescu, S.; Costantini, S.; Curceanu (Petrascu), C.; Doskarova, P.; Dreossi, D.; Drijard, D.; Dudarev, A.; Ferro-Luzzi, M.; Fungueirio Pazos, J. L.; Gallas Torreira, M.; Gerndt, J.; Gianotti, P.; Goldin, D.; Gomez, F.; Gorin, A.; Gorchakov, O.; Guaraldo, C.; Gugiu, M.; Hansroul, M.; Hons, Z.; Hosek, R.; Iliescu, M.; Karpukhin, V.; Kluson, J.; Kobayashi, M.; Kokkas, P.; Komarov, V.; Kruglov, V.; Kruglova, L.; Kulikov, A.; Kuptsov, A.; Kuroda, K. I.; Lamberto, A.; Lanaro, A.; Lapshin, V.; Lednicky, R.; Leruste, P.; Levi Sandri, P.; Lopez Aguera, A.; Lucherini, V.; Maki, T.; Manuilov, I.; Marin, J.; Narjoux, J. L.; Nemenov, L.; Nikitin, M.; Nunez Pardo, T.; Okada, K.; Olchevskii, V.; Pazos, A.; Pentia, M.; Penzo, A.; Perreau, J. M.; Plo, M.; Ponta, T.; Rappazzo, G. F.; Riazantsev, A.; Rodriguez, J. M.; Rodriguez Fernandez, A.; Romero Vidal, A.; Ronjin, V. M.; Rykalin, V.; Saborido, J.; Santamarina, C.; Schacher, J.; Schuetz, C.; Sidorov, A.; Smolik, J.; Takeutchi, F.; Tarasov, A.; Tauscher, L.; Tobar, M. J.; Trojek, T.; Trusov, S.; Utkin, V.; Vzquez Doce, O.; Vlachos, S.; Voskresenskaya, O.; Vrba, T.; Willmott, C.; Yazkov, V.; Yoshimura, Y.; Zhabitsky, M.; Zrelov, P.
2011-10-01
The DIRAC experiment at CERN has achieved a sizeable production of ?? atoms and has significantly improved the precision on its lifetime determination. From a sample of 21 227 atomic pairs, a 4% measurement of the S-wave ?? scattering length difference |a-a||syst-0.0073+0.0078)M?-1 has been attained, providing an important test of Chiral Perturbation Theory.
Alignment techniques required by precise measurement of effective focal length
NASA Technical Reports Server (NTRS)
Wise, T. D.
1980-01-01
The characteristics of false color imagery produced by instrumentation on earth resource mapping satellites are examined. The spatial fidelity of the imagery is dependent upon the geometric accuracy (GA) and the band-to-band registration (BBR) with which the telescope instrument is assembled. BBR and GA require knowledge of telescope effective focal length (EFL) to one part in 10,000 in order that the next generation of earth mappers be able to carry out their missions. The basis for this level of precision is briefly considered, and a description is given of the means by which such precise EFL measurements have been carried out. Attention is given to accuracy requirements, the technique used to measure effective focal length, possible sources of error in the EFL measurement, approaches for eliminating errors, and the results of the efforts to control measurement errors in EFL determinations.
Length Scale Correlations of Cellular Microstructures in Directionally Solidified Binary System
Yunxue Shen
2002-08-01
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.
Length Scale Correlations of Cellular Microstructures in Directionally Solidified Binary System
Yunxue Shen
2002-06-27
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.
Novel sensors for continuous crack-length measurement
NASA Technical Reports Server (NTRS)
Prabhakaran, R.; Ramasamy, M.
1992-01-01
A continuous crack-length sensor, fabricated from a carbon powder filled polymer, is described. The paper describes the basic sensor as well as some suggestions for improving the response by altering the sensor shape. The paper also describes two modes of using the sensor: measuring the change in electrical resistance and measuring the potential drop when a constant current is passed through the gage. The paper concludes with some results showing the temperature sensitivity of the sensor.
FEL GAIN LENGTH AND TAPER MEASUREMENTS AT LCLS
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
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.
How to Directly Measure a Kondo Cloud's Length
NASA Astrophysics Data System (ADS)
Park, Jinhong; Lee, S.-S. B.; Oreg, Yuval; Sim, H.-S.
2013-06-01
We propose a method to directly measure, by electrical means, the Kondo screening cloud formed by an Anderson impurity coupled to semi-infinite quantum wires, on which an electrostatic gate voltage is applied at distance L from the impurity. We show that the Kondo cloud, and hence the Kondo temperature and the electron conductance through the impurity, are affected by the gate voltage, as L decreases below the Kondo cloud length. Based on this behavior, the cloud length can be experimentally identified by changing L with a keyboard type of gate voltage or tuning the coupling strength between the impurity and the wires.
Minimal length in quantum gravity and gravitational measurements
NASA Astrophysics Data System (ADS)
Farag Ali, Ahmed; Khalil, Mohammed M.; Vagenas, Elias C.
2015-10-01
The existence of a minimal length is a common prediction of various theories of quantum gravity. This minimal length leads to a modification of the Heisenberg uncertainty principle to a Generalized Uncertainty Principle (GUP). Various studies showed that a GUP modifies the Hawking radiation of black holes. In this paper, we propose a modification of the Schwarzschild metric based on the modified Hawking temperature derived from the GUP. Based on this modified metric, we calculate corrections to the deflection of light, time delay of light, perihelion precession, and gravitational redshift. We compare our results with gravitational measurements to set an upper bound on the GUP parameter.
FEL Gain Length and Taper Measurements at LCLS
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.; ,
2010-07-30
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.
Correlation of axial length and corneal curvature with diopter in eyes of adults with anisometropia
Zeng, Jin; Cui, Ying; Li, Juan; Xie, Wenjuan; Li, Zhongming; Zhang, Liang; Meng, Qianli
2015-01-01
Purpose: To analyze the causes of anisometropia. Methods: Between June 2011 and November 2012 101 participants were divided into three groups. The refraction comprising the degree of refractive errors in the presence of astigmatism which was converted into the degree of spherical equivalent as well as ocular axial length (AL), corneal curvature (CR), average corneal power (ave K) and diopters were measured. Results: The differences of ocular AL/CR and CR between two eyes were statistically significant among the three groups (P < 0.05). Standardized regression coefficients obtained by a multiple linear regression analysis indicated that AL/CR, AL and ave K differences correlated with anisometropia in descending order. Conclusion: The difference of AL/CR ratios between the eyes was the main cause for anisometropia, followed by AL and ave K values. PMID:26550307
Sarti, D.; Chareyron, B.; Le, Q.N.; Bastide, S.; Lincot, D.
1994-12-31
The authors report on a method based on photoelectrochemistry which allows the measurement of diffusion lengths of multicrystalline silicon before fabricating the photovoltaic device. The results obtained with this method after two years experience on a production line, by the photovoltaic manufacturer Photowatt Int. are presented. It concerns the variation of the diffusion length within the ingots and its correlation with the short-circuit current of the final cells, and the effect of industrial gettering. The authors also present diffusion length maps on a 10 x 10 cm{sup 2} cell.
Reducing trial length in force platform posturographic sleep deprivation measurements
NASA Astrophysics Data System (ADS)
Forsman, P.; Hæggström, E.; Wallin, A.
2007-09-01
Sleepiness correlates with sleep-related accidents, but convenient tests for sleepiness monitoring are scarce. The posturographic test is a method to assess balance, and this paper describes one phase of the development of a posturographic sleepiness monitoring method. We investigated the relationship between trial length and accuracy of the posturographic time-awake (TA) estimate. Twenty-one healthy adults were kept awake for 32 h and their balance was recorded, 16 times with 30 s trials, as a function of TA. The balance was analysed with regards to fractal dimension, most common sway amplitude and time interval for open-loop stance control. While a 30 s trial allows estimating the TA of individual subjects with better than 5 h accuracy, repeating the analysis using shorter trial lengths showed that 18 s sufficed to achieve the targeted 5 h accuracy. Moreover, it was found that with increasing TA, the posturographic parameters estimated the subjects' TA more accurately.
Effective crack lengths by compliance measurement for ARALL-2 laminates
NASA Astrophysics Data System (ADS)
Wilson, Christopher D.; Wilson, Dale A.
As a means of determining a stress intensity factor solution, the compliance properties of an ARALL-2 laminated-sheet composite were investigated. Fatigue crack growth rate (FCGR) tests were conducted on middle crack tension (MT) specimens fabricated from a layup consisting of three sheets of 2024-T3 aluminum bonded together with unidirectional aramid fibers embedded in epoxy. Excellent fatigue crack growth properties are obtained by the presence of unbroken aramid fibers in the wake of the crack tip. These unbroken fibers act as a bridging mechanism to inhibit further crack growth. To quantify the effect of maximum fatigue load on compliance, a series of FCGR tests were performed. Effective crack lengths were determined to be at least 10 mm shorter than surface measured crack lengths for a 76-mm-wide specimen. The bridging zone was estimated to be at least 5 mm. Compliance and stress intensity factor as functions of effective crack length were determined.
Effective crack lengths by compliance measurement for ARALL-2 laminates
NASA Technical Reports Server (NTRS)
Wilson, Christopher D.; Wilson, Dale A.
1991-01-01
As a means of determining a stress intensity factor solution, the compliance properties of an ARALL-2 laminated-sheet composite were investigated. Fatigue crack growth rate (FCGR) tests were conducted on middle crack tension (MT) specimens fabricated from a layup consisting of three sheets of 2024-T3 aluminum bonded together with unidirectional aramid fibers embedded in epoxy. Excellent fatigue crack growth properties are obtained by the presence of unbroken aramid fibers in the wake of the crack tip. These unbroken fibers act as a bridging mechanism to inhibit further crack growth. To quantify the effect of maximum fatigue load on compliance, a series of FCGR tests were performed. Effective crack lengths were determined to be at least 10 mm shorter than surface measured crack lengths for a 76-mm-wide specimen. The bridging zone was estimated to be at least 5 mm. Compliance and stress intensity factor as functions of effective crack length were determined.
Minimum description length (MDL)-based arithmetic coding for correlated Markov states
NASA Astrophysics Data System (ADS)
Matsushiro, Nobuhito; Asada, Osamu
1995-03-01
In a description of a data by using arithmetic coding, coding parameters are estimated for each markov state independently. However, markov states are not completely uncorrelated in many cases. By utilizing the correlation, we can decrease estimation errors of coding parameters and improves compression performance. The utilization of the correlation can be included in the MDL (Minimum Description Length) framework. We have developed an MDL-based arithmetic coding for correlated markov states.
Negative correlation between age of subjects and length of the appendix in Bangladeshi males
Bakar, Sheikh Muhammad Abu; Shamim, Manjare; Alam, Gazi Mahabubul
2013-01-01
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
Developing measurement concepts within context: Children's representations of length
NASA Astrophysics Data System (ADS)
MacDonald, Amy; Lowrie, Tom
2011-03-01
This article presents data gathered from an investigation which focused on the experiences children have with measurement in the early years of schooling. The focus of this article is children's understandings of length at this early stage. 32 children aged 4-6 years at an Australian primary school were asked to draw a ruler and describe their drawing, once in February at the beginning of school, and again in November towards the end of their first year of school. The drawings and their accompanying descriptions are classified within a matrix which, informed by Bronfenbrenner's ecological theory and literature regarding the development of length concepts, considers conceptual understanding and contextual richness. The responses revealed that children have a good understanding of length at the start of school, but that as their ability to contextualise develops so too does their conceptual understanding. This article suggests that participation in tasks such as these allows children to create their own understandings of length in meaningful ways. Additionally, the task and its matrix of analysis provide an assessment strategy for identifying children's understandings about length and the contexts in which these understandings develop.
Electron Bunch Length Measurement for LCLS at SLAC
Zelazny, M.; Allison, S.; Chevtsov, Sergei; Emma, P.; Kotturi, K.d.; Loos, H.; Peng, S.; Rogind, D.; Straumann, T.; /SLAC
2007-10-04
At Stanford Linear Accelerator Center (SLAC) a Bunch Length Measurement system has been developed to measure the length of the electron bunch for its new Linac Coherent Light Source (LCLS). This destructive measurement uses a transverse-mounted RF deflector (TCAV) to vertically streak the electron beam and an image taken with an insertable screen and a camera. The device control software was implemented with the Experimental Physics and Industrial Control System (EPICS) toolkit. The analysis software was implemented in Matlab{trademark} using the EPICS/Channel Access Interface for Scilab{trademark} and Matlab{trademark} (labCA). This architecture allowed engineers and physicists to develop and integrate their control and analysis without duplication of effort.
Equivalence and Accuracy of MOSFET Channel Length Measurement Techniques
NASA Astrophysics Data System (ADS)
Jain, Sanjay
1989-02-01
It is shown that the MOSFET channel length measurement techniques of Terada and Muta, Peng et al., Whitfield, Suciu and Johnston, and De La Moneda et al. are actually equivalent, i.e. merely different expressions of the same formula for channel length in terms of measured resistance, and that some of the transresistance methods of Jain, although not equivalent, are also related to the same formula. The accuracy of this formula is evaluated for the general case and related to the error components due to source and drain resistance asymmetry, short channel geometry effect, and variation of series resistance with bias. No independent error component due to field-induced mobility degradation is found. Finally the errors in the methods of Terada and Muta, Chen et al., Sheu et al., Wordeman et al. and Jain, are determined and compared. The gate transresistance technique is found to be the most accurate method.
Interaural correlations in normal and traumatized cochleas: length and sensory cell loss
Bohne, B.A.; Bozzay, D.G.; Harding, G.W.
1986-12-01
Sizable intraspecies variations have been found in both the length of the organ of Corti (OC) and the amount of damage resulting from exposure to a particular ototraumatic agent. These variations have made it difficult to address certain research questions such as the susceptibility of the previously injured ear to further damage. If intra-animal correlation is high, the variability problem could be circumvented by using the two ears from a given animal for different aspects of the same study. Therefore, correlation coefficients were calculated for OC length and for percentage of missing inner (IHCs) and outer hair cells (OHCs) in a large sample of chinchillas which included controls and animals which had been exposed to noise or treated with ionizing radiation. The correlation coefficients were +0.96 for OC length, +0.93 for IHC loss, and +0.97 for OHC loss.
Comeron, J M; Kreitman, M
2000-01-01
Intron length is negatively correlated with recombination in both Drosophila melanogaster and humans. This correlation is not likely to be the result of mutational processes alone: evolutionary analysis of intron length polymorphism in D. melanogaster reveals equivalent ratios of deletion to insertion in regions of high and low recombination. The polymorphism data do reveal, however, an excess of deletions relative to insertions (i.e., a deletion bias), with an overall deletion-to-insertion events ratio of 1.35. We propose two types of selection favoring longer intron lengths. First, the natural mutational bias toward deletion must be opposed by strong selection in very short introns to maintain the minimum intron length needed for the intron splicing reaction. Second, selection will favor insertions in introns that increase recombination between mutations under the influence of selection in adjacent exons. Mutations that increase recombination, even slightly, will be selectively favored because they reduce interference among selected mutations. Interference selection acting on intron length mutations must be very weak, as indicated by frequency spectrum analysis of Drosophila intron length polymorphism, making the equilibrium for intron length sensitive to changes in the recombinational environment and population size. One consequence of this sensitivity is that the advantage of longer introns is expected to decrease inversely with the rate of recombination, thus leading to a negative correlation between intron length and recombination rate. Also in accord with this model, intron length differs between closely related Drosophila species, with the longest variant present more often in D. melanogaster than in D. simulans. We suggest that the study of the proposed dynamic model, taking into account interference among selected sites, might shed light on many aspects of the comparative biology of genome sizes including the C value paradox. PMID:11063693
Absolute Bunch Length Measurements by Incoherent Radiation Fluctuation Analysis
Sannibale, F.; Stupakov, G.V.; Zolotorev, M.S.; Filippetto, D.; Jagerhofer, L.; /Vienna, Tech. U.
2009-12-09
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.
Absolute bunch length measurements by incoherent radiation fluctuation analysis
Sannibale, Fernando; Stupakov, Gennady; Zolotorev, Max; Filippetto, Daniele; Jagerhofer, Lukas
2008-09-29
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.
Cross-correlation between length and position in real fracture networks
NASA Astrophysics Data System (ADS)
Darcel, C.; Bour, O.; Davy, P.
2003-06-01
By analyzing local geometrical properties of a dense multiscale fracture pattern, we characterized statistically the correlations between length and position of a fracture. Apart from some resolution effects, we show that the mean distance between a fracture center and its nearest neighbor is correlated to its length l such as d ~ l 0.3. Likewise, the average area around each fracture center within which no other fracture portion is lying has an ellipsoidal shape whose factor of anisotropy is correlated to l. The long axis, along fracture strike, is correlated to l such as d ~ l 0. 25-0.3. The short axis remains invariant, about equal to the equivalent distance in a random fractal. At small scale (i.e., less than 1 m which is bed thickness) the shield area is isotropic. In addition to refining of geometrical model of fracture networks, such observations place some constraints on the stress interactions that prevail during fracture growth.
Direct calculation of correlation length based on quasi-cumulant method
NASA Astrophysics Data System (ADS)
Fukushima, Noboru
2014-03-01
We formulate a method of directly obtaining a correlation length without full calculation of correlation functions, as a high-temperature series. The method is based on the quasi-cumulant method, which was formulated by the author in J. Stat. Phys. 111, 1049-1090 (2003) as a complementary method for the high-temperature series expansion originally for an SU(n) Heisenberg model, but is applicable to general spin models according to our recent reformulation. A correlation function divided by its lowest-order nonzero contribution has properties very similar to a generating function of some kind of moments, which we call quasi-moments. Their corresponding quasi-cumulants can be also derived, whose generating function is related to the correlation length. In addition, applications to other numerical methods such as the quantum Monte Carlo method are also discussed. JSPS KAKENHI Grant Number 25914008.
Humphries, T D; Sheppard, D A; Buckley, C E
2015-06-30
For homoleptic 18-electron complex hydrides, an inverse linear correlation has been established between the T-deuterium bond length (T = Fe, Co, Ni) and the average electronegativity of the metal countercations. This relationship can be further employed towards aiding structural solutions and predicting physical properties of novel complex transition metal hydrides. PMID:26077621
Thin-filament length correlates with fiber type in human skeletal muscle
Gokhin, David S.; Kim, Nancy E.; Lewis, Sarah A.; Hoenecke, Heinz R.; D'Lima, Darryl D.
2012-01-01
Force production in skeletal muscle is proportional to the amount of overlap between the thin and thick filaments, which, in turn, depends on their lengths. Both thin- and thick-filament lengths are precisely regulated and uniform within a myofibril. While thick-filament lengths are essentially constant across muscles and species (∼1.65 μm), thin-filament lengths are highly variable both across species and across muscles of a single species. Here, we used a high-resolution immunofluorescence and image analysis technique (distributed deconvolution) to directly test the hypothesis that thin-filament lengths vary across human muscles. Using deltoid and pectoralis major muscle biopsies, we identified thin-filament lengths that ranged from 1.19 ± 0.08 to 1.37 ± 0.04 μm, based on tropomodulin localization with respect to the Z-line. Tropomodulin localized from 0.28 to 0.47 μm further from the Z-line than the NH2-terminus of nebulin in the various biopsies, indicating that human thin filaments have nebulin-free, pointed-end extensions that comprise up to 34% of total thin-filament length. Furthermore, thin-filament length was negatively correlated with the percentage of type 2X myosin heavy chain within the biopsy and shorter in type 2X myosin heavy chain-positive fibers, establishing the existence of a relationship between thin-filament lengths and fiber types in human muscle. Together, these data challenge the widely held assumption that human thin-filament lengths are constant. Our results also have broad relevance to musculoskeletal modeling, surgical reattachment of muscles, and orthopedic rehabilitation. PMID:22075691
Karti, Omer; Selver, Ozlem B; Karahan, Eyyup; Zengin, Mehmet O; Uyar, Murat
2015-01-01
Purpose : To evaluate the normal distribution of exophthalmometric values in Turkish adult population and the effect of age, gender, refractive status and axial length on globe position. Methods : One hundred and twenty-two males and 114 healthy females with age ranging from 18 to 87 years were included in the study. The study population was recruited from patients presenting to our institution for routine refractive examination. Hertel exophthalmometer was used to measure the degree of ocular protrusion. Effect of age, refractive error, interpupillary distance, and axial length on globe position was detected with linear regression analyses. Results : The mean Hertel exophthalmometric size was 15.7+2.6 mm (range; 11 to 21 mm). The mean value for males was 16.1±2.6 mm (range; 11 to 21 mm), and for females 15.5±2.6 mm (range; 11 to 20 mm). The mean distance between the lateral rims of the orbit was 102 + 5.1 mm (range; 88 to 111mm). The mean exophthalmometric values were not statistically different in males and females. Age and mean spherical equivalents were negatively correlated with exophthalmometric measurements. Axial length was positively correlated with exophthalmometric measurements. Conclusion : The exophthalmometric measurement of the eye is affected by the age, spherical equivalent and the axial length. Standard normative values of the Hertel exophthalmometric measurements should be reevaluated with larger samples. PMID:26089994
Measurements of Correlation-Enhanced Collision Rates
NASA Astrophysics Data System (ADS)
Driscoll, C. Fred
2009-11-01
This talk presents the first detailed experimental measurements of the Salpeter collisional enhancement factor g ( γ) 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 γ≡e^2 /aT is larger than unity, scaling as g ( γ) ˜e^γ. The perp-to-parallel collision rate is then ν|= n v b^2 ,( κ ) ,( γ), where I ( κ ) decreases precipitously below ( 8 √π / 15 ) λ in the highly magnetized regime of κ ≡√2 ,/ rc1. Our measurementsfootnotetextF. Anderegg et al., Phys. Rev. Lett. 102, 185001 (2009); F. Anderegg et al., Phys. Plasmas 16, 055705 (2009). of ν| 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 < ν|< 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 = ν|/ 2 πc (γ), where c ( γ) 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 ν|T-3/2 regime at high temperatures, and show the strong I ( κ ) suppression of ν| for b / rc1. At low temperatures and high density, the measured ν| 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.
Correlated measurement error hampers association network inference.
Kaduk, Mateusz; Hoefsloot, Huub C J; Vis, Daniel J; Reijmers, Theo; van der Greef, Jan; Smilde, Age K; Hendriks, Margriet M W B
2014-09-01
Modern chromatography-based metabolomics measurements generate large amounts of data in the form of abundances of metabolites. An increasingly popular way of representing and analyzing such data is by means of association networks. Ideally, such a network can be interpreted in terms of the underlying biology. A property of chromatography-based metabolomics data is that the measurement error structure is complex: apart from the usual (random) instrumental error there is also correlated measurement error. This is intrinsic to the way the samples are prepared and the analyses are performed and cannot be avoided. The impact of correlated measurement errors on (partial) correlation networks can be large and is not always predictable. The interplay between relative amounts of uncorrelated measurement error, correlated measurement error and biological variation defines this impact. Using chromatography-based time-resolved lipidomics data obtained from a human intervention study we show how partial correlation based association networks are influenced by correlated measurement error. We show how the effect of correlated measurement error on partial correlations is different for direct and indirect associations. For direct associations the correlated measurement error usually has no negative effect on the results, while for indirect associations, depending on the relative size of the correlated measurement error, results can become unreliable. The aim of this paper is to generate awareness of the existence of correlated measurement errors and their influence on association networks. Time series lipidomics data is used for this purpose, as it makes it possible to visually distinguish the correlated measurement error from a biological response. Underestimating the phenomenon of correlated measurement error will result in the suggestion of biologically meaningful results that in reality rest solely on complicated error structures. Using proper experimental designs that allow for the quantification of the size of correlated and uncorrelated errors, can help to identify suspicious connections in association networks constructed from (partial) correlations. PMID:24951433
An easy measure of quantum correlation
NASA Astrophysics Data System (ADS)
Cao, Hui; Wu, Zhao-Qin; Hu, Li-Yun; Xu, Xue-Xiang; Huang, Jie-Hui
2015-11-01
To measure the quantum correlation of a bipartite state, a test matrix is constructed through the commutations among the blocks of its density matrix, which turns out to be a zero matrix for a classical state with zero quantum correlation, and a nonzero one for a quantum state with positive quantum correlation. The Frobenius norm of the test matrix is used to measure the quantum correlation, which satisfies the basic requirements for a good measure and coincides with Wootters concurrence for two-qubit pure states. Since no optimization is involved in the definition, this measure of quantum correlation is easy to compute and even can be calculated manually.
Comparison of three methods of measuring the atmospheric coherence length
NASA Astrophysics Data System (ADS)
Slavin, Ann C.; Wells, Ann L.; Fugate, Robert Q.; Fried, David L.; Drexler, James J.
1997-09-01
In the fall of 1996, we had the opportunity to mneasure the atmospheric coherence length (Fried's r0 parameter) at the STarfire Optical Range using three instruments. Each instrument measured r0 using a different theory and technique. The first instrument, designed and built by Dr. Donald Walters of the Naval Postgraduate School, is based on measuring the MTF of the atmosphere using a stellar image on a one dimensional detector. The second instrument, designed and built by Lockheed Martin engineers at White Sands Missile Range, is based on measuring the differential motion of stellar images. The third technique in this study used short exposure star images taken through the 1.5m telescope and processed by matching the images to shrot exposure theory values of r0. All of the instruments were located at the STarfire Optical Range and data were collected during both day and night hours. This paper presents the results of these measurements and discusses the different techniques in terms of the results obtained.
Influence of tapered thermowell length on temperature measurement
Zhou, Z.J.; Motriuk, R.W.
1996-12-01
Temperature probe assemblies are frequently subjected to vibrations at their natural frequencies. Centrifugal compressor generated acoustic energy is large enough to excite piping and the temperature probe assemblies attached to it. Vibration of the assemblies leads to their component failures. The thermowell is a main mechanical component of such an assembly and it often fails due to fatigue phenomena. Incidents of thermowell failures at Nova Gas Transmission Limited (NGTL) piping system triggered a complete review of the company standard defining design of a temperature probe assembly. The proposed new standard recommends a reduction of the thermowell insertion length from six to three inches. Implementation of this recommendation changes the mechanical natural frequencies (MNFs) of the temperature probe assembly. To ensure that the modified temperature probe assembly has an adequate temperature measurement accuracy and acceptable response time, a number of heat transfer analyses have been performed. This paper summarizes the analytical results taking into account the following factors: (i) the effects of gas pressure, velocity, and material properties on the accuracy of measurement, (ii) the time required to obtain a reasonable measurement accuracy, and (iii) implications of design changes on the measurement procedure.
Correlation between weighted spectral distribution and average path length in evolving networks.
Jiao, Bo; Shi, Jianmai; Wu, Xiaoqun; Nie, Yuanping; Huang, Chengdong; Du, Jing; Zhou, Ying; Guo, Ronghua; Tao, Yerong
2016-02-01
The weighted spectral distribution (WSD) is a metric defined on the normalized Laplacian spectrum. In this study, synchronic random graphs are first used to rigorously analyze the metric's scaling feature, which indicates that the metric grows sublinearly as the network size increases, and the metric's scaling feature is demonstrated to be common in networks with Gaussian, exponential, and power-law degree distributions. Furthermore, a deterministic model of diachronic graphs is developed to illustrate the correlation between the slope coefficient of the metric's asymptotic line and the average path length, and the similarities and differences between synchronic and diachronic random graphs are investigated to better understand the correlation. Finally, numerical analysis is presented based on simulated and real-world data of evolving networks, which shows that the ratio of the WSD to the network size is a good indicator of the average path length. PMID:26931591
Correlation between weighted spectral distribution and average path length in evolving networks
NASA Astrophysics Data System (ADS)
Jiao, Bo; Shi, Jianmai; Wu, Xiaoqun; Nie, Yuanping; Huang, Chengdong; Du, Jing; Zhou, Ying; Guo, Ronghua; Tao, Yerong
2016-02-01
The weighted spectral distribution (WSD) is a metric defined on the normalized Laplacian spectrum. In this study, synchronic random graphs are first used to rigorously analyze the metric's scaling feature, which indicates that the metric grows sublinearly as the network size increases, and the metric's scaling feature is demonstrated to be common in networks with Gaussian, exponential, and power-law degree distributions. Furthermore, a deterministic model of diachronic graphs is developed to illustrate the correlation between the slope coefficient of the metric's asymptotic line and the average path length, and the similarities and differences between synchronic and diachronic random graphs are investigated to better understand the correlation. Finally, numerical analysis is presented based on simulated and real-world data of evolving networks, which shows that the ratio of the WSD to the network size is a good indicator of the average path length.
NASA Astrophysics Data System (ADS)
Lee, Chih-Hao; Chang, Hsin-Ho; Su, Hui-Chia; Wu, Yu-Han; Hu, Chih-Wei; Chang, L. J.; Ioffe, A.; Bussmann, K.; Brückel, Th.
2009-09-01
The magnetic correlation length of a mixed nickel ferrite powder was studied by a newly commissioned depolarized neutron beamline at the W3 port of Tsing Hua Open Pool Reactor (THOR). In this work, Ni ferrite powder samples with different packing densities were studied. The magnetic correlation lengths of the sample were observed to be 2 μm at virgin state and about 3.1 μm at remanent state from the packing density of 20-60%. This magnetic domain size is smaller than particle size. No significant change of domain size at this packing density implies the domain wall motion is hindered by the porosity effectively up to at least 60% of packing density.
NASA Astrophysics Data System (ADS)
Gleich, Otto; Dooling, Robert J.; Manley, Geoffrey A.
2005-12-01
The inner ear in the group of archosaurs (birds, crocodilians, and extinct dinosaurs) shows a high degree of structural similarity, enabling predictions of their function in extinct species based on relationships among similar variables in living birds. Behavioral audiograms and morphological data on the length of the auditory sensory epithelium (the basilar papilla) are available for many avian species. By bringing different data sets together, we show that body mass and the size of the basilar papilla are significantly correlated, and the most sensitive frequency in a given species is inversely related to the body mass and the length of the basilar papilla. We also demonstrate that the frequency of best hearing is correlated with the high-frequency limit of hearing. Small species with a short basilar papilla hear higher frequencies compared with larger species with a longer basilar papilla. Based on the regression analysis of two significant correlations in living archosaurs (best audiogram frequency vs body mass and best audiogram frequency vs papillar length), we suggest that hearing in large dinosaurs was restricted to low frequencies with a high-frequency limit below 3 kHz.
Aulinas, Anna; Ramírez, María-José; Barahona, María-José; Valassi, Elena; Resmini, Eugenia; Mato, Eugènia; Santos, Alicia; Crespo, Iris; Bell, Olga; Surrallés, Jordi; Webb, Susan M.
2015-01-01
Introduction Cushing’s syndrome (CS) increases cardiovascular risk (CVR) and adipocytokine imbalance, associated with an increased inflammatory state. Telomere length (TL) shortening is a novel CVR marker, associated with inflammation biomarkers. We hypothesized that inflammatory state and higher CVR in CS might be related to TL shortening, as observed in premature aging. Aim To evaluate relationships between TL, CVR and inflammation markers in CS. Methods In a cross-sectional study, 77 patients with CS (14 males, 59 pituitary-, 17 adrenal- and 1 ectopic-origin; 21 active disease) and 77 age-, gender-, smoking-matched controls were included. Total white blood cell TL was measured by TRF-Southern technique. Clinical data and blood samples were collected (lipids, adrenal function, glucose). Adiponectin, interleukin-6 (IL6) and C-reactive protein (CRP) were available in a subgroup of patients (n=32). Correlations between TL and clinical features were examined and multiple linear regression analysis was performed to investigate potential predictors of TL. Results Dyslipidemic CS had shorter TL than non-dyslipidemic subjects (7328±1274 vs 7957±1137 bp, p<0.05). After adjustment for age and body mass index, cured and active CS dyslipidemic patients had shorter TL than non-dyslipidemic CS (cured: 7187±1309 vs 7868±1104; active: 7203±1262 vs 8615±1056, respectively, p<0.05). Total cholesterol and triglycerides negatively correlated with TL (r-0.279 and -0.259, respectively, p<0.05), as well as CRP and IL6 (r-0.412 and -0.441, respectively, p<0.05). No difference in TL according the presence of other individual CVR factors (hypertension, diabetes mellitus, obesity) were observed in CS or in the control group. Additional TL shortening was observed in dyslipidemic obese patients who were also hypertensive, compared to those with two or less CVR factors (6956±1280 vs 7860±1180, respectively, p<0.001). Age and dyslipidemia were independent negative predictors of TL. Conclusion TL is shortened in dyslipidemic CS patients, further worse if hypertension and/or obesity coexist and is negatively correlated with increased inflammation markers. Increased lipids and a “low” grade inflammation may contribute to TL shortening and consequently to premature ageing and increased morbidity in CS. PMID:25799396
Representative Elementary Length to Measure Soil Mass Attenuation Coefficient
Borges, J. A. R.; Pires, L. F.; Costa, J. C.
2014-01-01
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 (μs) is an important parameter for CT and GAT analysis. When experimentally determined (μes), 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 μes 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 μes 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 (ρs). As a consequence, ρs might be under- or overestimated, generating inaccurate conclusions about the physical quality of the soil under study. PMID:24672338
Vojtisek-Lom, Michal
2011-02-01
To evaluate the effectiveness of various means to combat the negative health effects of ultrafine particles emitted by internal combustion engines, a reliable, low-cost instrument for dynamic measurements of the exhaust emissions of ultrafine particulate matter (PM) is needed. In this study, an ordinary ionization-type building smoke detector was modified to serve as a measuring ionization chamber and utilized for dynamic measurements of PM emissions from diesel engines. When used with diluted exhaust, the readings show an excellent correlation with total particulate length. The instrument worked well with raw and diluted exhaust and with varying emission levels and is well suitable for on-board use. PMID:21387930
NASA Astrophysics Data System (ADS)
St. Martin, Clara M.; Lundquist, Julie K.; Handschy, Mark A.
2015-04-01
The variability in wind-generated electricity complicates the integration of this electricity into the electrical grid. This challenge steepens as the percentage of renewably-generated electricity on the grid grows, but variability can be reduced by exploiting geographic diversity: correlations between wind farms decrease as the separation between wind farms increases. But how far is far enough to reduce variability? Grid management requires balancing production on various timescales, and so consideration of correlations reflective of those timescales can guide the appropriate spatial scales of geographic diversity grid integration. To answer ‘how far is far enough,’ we investigate the universal behavior of geographic diversity by exploring wind-speed correlations using three extensive datasets spanning continents, durations and time resolution. First, one year of five-minute wind power generation data from 29 wind farms span 1270 km across Southeastern Australia (Australian Energy Market Operator). Second, 45 years of hourly 10 m wind-speeds from 117 stations span 5000 km across Canada (National Climate Data Archive of Environment Canada). Finally, four years of five-minute wind-speeds from 14 meteorological towers span 350 km of the Northwestern US (Bonneville Power Administration). After removing diurnal cycles and seasonal trends from all datasets, we investigate dependence of correlation length on time scale by digitally high-pass filtering the data on 0.25-2000 h timescales and calculating correlations between sites for each high-pass filter cut-off. Correlations fall to zero with increasing station separation distance, but the characteristic correlation length varies with the high-pass filter applied: the higher the cut-off frequency, the smaller the station separation required to achieve de-correlation. Remarkable similarities between these three datasets reveal behavior that, if universal, could be particularly useful for grid management. For high-pass filter time constants shorter than about τ = 38 h, all datasets exhibit a correlation length ξ that falls at least as fast as {{τ }-1} . Since the inter-site separation needed for statistical independence falls for shorter time scales, higher-rate fluctuations can be effectively smoothed by aggregating wind plants over areas smaller than otherwise estimated.
Measurement of the Length of an Optical Trap
NASA Technical Reports Server (NTRS)
Wrbanek, Susan Y.
2010-01-01
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.
Kociszewski, Jacek; Suzin, Jacek; Dresler, Maria; Surkont, Grzegorz
2016-01-01
There has been a rise in the use of sonographic urethrocystography in patients with a full bladder. So far, no publications have been made on the analysis of repeatability and reproducibility of the measurements performed during this procedure. Aim An assessment of repeatability and reproducibility of urethral length measurements during sonographic urethrocystography in females with a full bladder in the introital approach, using real-time two-dimensional transvaginal ultrasound. Material and methods The ultrasound was performed in accordance with a standardized technique in female patients with a full bladder containing 200–300 mL of liquid. A total of 92 patients were included in the analysis. Results The Intraclass Correlation Coefficient for repeatability and reproducibility of urethral length measurements in sonographic urethrocystography ranged between 0.9217 and 0.9873 (p = 0.0000). The analysis of ultrasound urethral length measurements taken by two different physicians at an interval of several months confirmed their very high compatibility (ICC = 0.81, p = 0.000). Conclusions Very good repeatability and reproducibility of urethral length findings during sonographic urethrocystography performed in accordance with the presented technique support the possible use of this type of examination in both clinical practice and research. PMID:27104000
Postulates for measures of genuine multipartite correlations
Bennett, Charles H.; Grudka, Andrzej; Horodecki, Michal; Horodecki, Ryszard; Horodecki, Pawel
2011-01-15
A lot of research has been done on multipartite correlations, but the problem of satisfactorily defining genuine multipartite correlations--those not trivially reducible to lower partite correlations--remains unsolved. In this paper we propose three reasonable postulates which each measure or indicator of genuine multipartite correlations (or genuine multipartite entanglement) should satisfy. We also introduce the concept of degree of correlations, which gives partial characterization of multipartite correlations. Then, we show that covariance does not satisfy two postulates and hence it cannot be used as an indicator of genuine multipartite correlations. Finally, we propose a candidate for a measure of genuine multipartite correlations based on the work that can be drawn from a local heat bath by means of a multipartite state.
Optimal chirped probe pulse length for terahertz pulse measurement.
Peng, Xiao-Yu; Willi, Oswald; Chen, Min; Pukhov, Alexander
2008-08-01
A detailed analysis of the relationship between the duration of the chirped probe pulse and the bipolar terahertz (THz) pulse length in the spectral encoding technique is carried out. We prove that there is an optimal chirped probe pulse length (or an optimal chirp rate of the chirped probe pulse) matched to the input THz pulse length and derive a rigorous relationship between them. We find that only under this restricted condition the THz signal can be correctly retrieved. PMID:18679511
Hills, Peter J; Eaton, Elizabeth; Pake, J Michael
2016-04-01
Psychometric schizotypy in the general population correlates negatively with face recognition accuracy, potentially due to deficits in inhibition, social withdrawal, or eye-movement abnormalities. We report an eye-tracking face recognition study in which participants were required to match one of two faces (target and distractor) to a cue face presented immediately before. All faces could be presented with or without paraphernalia (e.g., hats, glasses, facial hair). Results showed that paraphernalia distracted participants, and that the most distracting condition was when the cue and the distractor face had paraphernalia but the target face did not, while there was no correlation between distractibility and participants' scores on the Schizotypal Personality Questionnaire (SPQ). Schizotypy was negatively correlated with proportion of time fixating on the eyes and positively correlated with not fixating on a feature. It was negatively correlated with scan path length and this variable correlated with face recognition accuracy. These results are interpreted as schizotypal traits being associated with a restricted scan path leading to face recognition deficits. PMID:25835241
Comeron, J M; Kreitman, M; Aguadé, M
1999-01-01
Evolutionary analysis of codon bias in Drosophila indicates that synonymous mutations are not neutral, but rather are subject to weak selection at the translation level. Here we show that the effectiveness of natural selection on synonymous sites is strongly correlated with the rate of recombination, in accord with the nearly neutral hypothesis. This correlation, however, is apparent only in genes encoding short proteins. Long coding regions have both a lower codon bias and higher synonymous substitution rates, suggesting that they are affected less efficiently by selection. Therefore, both the length of the coding region and the recombination rate modulate codon bias. In addition, the data indicate that selection coefficients for synonymous mutations must vary by a minimum of one or two orders of magnitude. Two hypotheses are proposed to explain the relationship among the coding region length, the codon bias, and the synonymous divergence and polymorphism levels across the range of recombination rates in Drosophila. The first hypothesis is that selection coefficients on synonymous mutations are inversely related to the total length of the coding region. The second hypothesis proposes that interference among synonymous mutations reduces the efficacy of selection on these mutations. We investigated this second hypothesis by carrying out forward simulations of weakly selected mutations in model populations. These simulations show that even with realistic recombination rates, this interference, which we call the "small-scale" Hill-Robertson effect, can have a moderately strong influence on codon bias. PMID:9872963
Keršič, Matej; Dolinar, Drago; Antolič, Vane; Mavčič, Blaž
2014-01-01
In a single-surgeon series of 119 patients with unilateral primary uncemented total hip arthroplasty, four leg-length discrepancy measurement methods (absolute, relative, trochanteric, standardized-trochanteric) were analyzed for their impact on WOMAC score, Oxford Hip Score and self-perceived leg-length discrepancy. After adjustment for age, gender and BMI, postoperative WOMAC scores correlated only with clinical absolute measurements of leg elongation (P=0.05). Self-perceived leg-length discrepancy corresponded best to the clinically measured relative leg-length discrepancy (11 mm perceived vs. 7 mm unperceived; P=0.04) while there was no significant correspondence with radiographic measurements or leg elongation magnitudes. Within the <10 mm range of mean postoperative leg length discrepancy in the studied series, its impact on the overall clinical satisfaction was detectable but not considerable. PMID:23680505
Measurements of the Influence of Integral Length Scale on Stagnation Region Heat Transfer
NASA Technical Reports Server (NTRS)
Vanfossen, G. James; Ching, Chang Y.
1994-01-01
The purpose was twofold: first, to determine if a length scale existed that would cause the greatest augmentation in stagnation region heat transfer for a given turbulence intensity and second, to develop a prediction tool for stagnation heat transfer in the presence of free stream turbulence. Toward this end, a model with a circular leading edge was fabricated with heat transfer gages in the stagnation region. The model was qualified in a low turbulence wind tunnel by comparing measurements with Frossling's solution for stagnation region heat transfer in a laminar free stream. Five turbulence generating grids were fabricated; four were square mesh, biplane grids made from square bars. Each had identical mesh to bar width ratio but different bar widths. The fifth grid was an array of fine parallel wires that were perpendicular to the axis of the cylindrical leading edge. Turbulence intensity and integral length scale were measured as a function of distance from the grids. Stagnation region heat transfer was measured at various distances downstream of each grid. Data were taken at cylinder Reynolds numbers ranging from 42,000 to 193,000. Turbulence intensities were in the range 1.1 to 15.9 percent while the ratio of integral length scale to cylinder diameter ranged from 0.05 to 0.30. Stagnation region heat transfer augmentation increased with decreasing length scale. An optimum scale was not found. A correlation was developed that fit heat transfer data for the square bar grids to within +4 percent. The data from the array of wires were not predicted by the correlation; augmentation was higher for this case indicating that the degree of isotropy in the turbulent flow field has a large effect on stagnation heat transfer. The data of other researchers are also compared with the correlation.
Estienne, B; Regnault, N; Bernevig, B A
2015-05-01
Using the newly developed matrix product state formalism for non-Abelian fractional quantum Hall (FQH) states, we address the question of whether a FQH trial wave function written as a correlation function in a nonunitary conformal field theory (CFT) can describe the bulk of a gapped FQH phase. We show that the nonunitary Gaffnian state exhibits clear signatures of a pathological behavior. As a benchmark we compute the correlation length of a Moore-Read state and find it to be finite in the thermodynamic limit. By contrast, the Gaffnian state has an infinite correlation length in (at least) the non-Abelian sector, and is therefore gapless. We also compute the topological entanglement entropy of several non-Abelian states with and without quasiholes. For the first time in the FQH effect the results are in excellent agreement in all topological sectors with the CFT prediction for unitary states. For the nonunitary Gaffnian state in finite size systems, the topological entanglement entropy seems to behave like that of the composite fermion Jain state at equal filling. PMID:26001015
Scale and time dependence of serial correlations in word-length time series of written texts
NASA Astrophysics Data System (ADS)
Rodriguez, E.; Aguilar-Cornejo, M.; Femat, R.; Alvarez-Ramirez, J.
2014-11-01
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.
NASA Astrophysics Data System (ADS)
Estienne, B.; Regnault, N.; Bernevig, B. A.
2015-05-01
Using the newly developed matrix product state formalism for non-Abelian fractional quantum Hall (FQH) states, we address the question of whether a FQH trial wave function written as a correlation function in a nonunitary conformal field theory (CFT) can describe the bulk of a gapped FQH phase. We show that the nonunitary Gaffnian state exhibits clear signatures of a pathological behavior. As a benchmark we compute the correlation length of a Moore-Read state and find it to be finite in the thermodynamic limit. By contrast, the Gaffnian state has an infinite correlation length in (at least) the non-Abelian sector, and is therefore gapless. We also compute the topological entanglement entropy of several non-Abelian states with and without quasiholes. For the first time in the FQH effect the results are in excellent agreement in all topological sectors with the CFT prediction for unitary states. For the nonunitary Gaffnian state in finite size systems, the topological entanglement entropy seems to behave like that of the composite fermion Jain state at equal filling.
The transport of low-frequency turbulence in astrophysical flows: Correlation lengths
NASA Astrophysics Data System (ADS)
Dosch, A.; Adhikari, L.; Zank, G. P.
2013-06-01
Recently, Zank et al. 2012 developed a model to describe the transport of low-frequency turbulence in inhomogeneous and magnetized flows, based on the Elsässer description. By taking moments of the small scale Elsässer variables z+/-, transport equations for the total energy ET, the cross helicity EC, and the energy difference (residual energy) ED of the turbulence were derived. The set of transport equations was completed by introducing evolution equations for the correlation lengths λ+/- (corresponding to forward and backward propagating modes of the Elsässer variable), and the correlation length λD (corresponding to the energy difference ED). A first simplification was achieved by setting λ+ = λ-. In this paper we show that, based on an integral scale for velocity correlations, the choice of λ+ = λ- has a certain phenomenology with some very specific implications on the set of transport equations. In particular, it is shown that λD and z+/- can no longer be chosen arbitrarily, but must satisfy certain restrictions. These are discussed and a reduced transport model is derived.
Line Tensions, Correlation Lengths, and Critical Exponents in Lipid Membranes Near Critical Points
Honerkamp-Smith, Aurelia R.; Cicuta, Pietro; Collins, Marcus D.; Veatch, Sarah L.; den Nijs, Marcel; Schick, M.; Keller, Sarah L.
2008-01-01
Membranes containing a wide variety of ternary mixtures of high chain-melting temperature lipids, low chain-melting temperature lipids, and cholesterol undergo lateral phase separation into coexisting liquid phases at a miscibility transition. When membranes are prepared from a ternary lipid mixture at a critical composition, they pass through a miscibility critical point at the transition temperature. Since the critical temperature is typically on the order of room temperature, membranes provide an unusual opportunity in which to perform a quantitative study of biophysical systems that exhibit critical phenomena in the two-dimensional Ising universality class. As a critical point is approached from either high or low temperature, the scale of fluctuations in lipid composition, set by the correlation length, diverges. In addition, as a critical point is approached from low temperature, the line tension between coexisting phases decreases to zero. Here we quantitatively evaluate the temperature dependence of line tension between liquid domains and of fluctuation correlation lengths in lipid membranes to extract a critical exponent, ?. We obtain ? = 1.2 0.2, consistent with the Ising model prediction ? = 1. We also evaluate the probability distributions of pixel intensities in fluorescence images of membranes. From the temperature dependence of these distributions above the critical temperature, we extract an independent critical exponent of ? = 0.124 0.03, which is consistent with the Ising prediction of ? = 1/8. PMID:18424504
On the measurability of quantum correlation functions
Lima Bernardo, Bertúlio de Azevedo, Sérgio; Rosas, Alexandre
2015-05-15
The concept of correlation function is widely used in classical statistical mechanics to characterize how two or more variables depend on each other. In quantum mechanics, on the other hand, there are observables that cannot be measured at the same time; the so-called incompatible observables. This prospect imposes a limitation on the definition of a quantum analog for the correlation function in terms of a sequence of measurements. Here, based on the notion of sequential weak measurements, we circumvent this limitation by introducing a framework to measure general quantum correlation functions, in principle, independently of the state of the system and the operators involved. To illustrate, we propose an experimental configuration to obtain explicitly the quantum correlation function between two Pauli operators, in which the input state is an arbitrary mixed qubit state encoded on the polarization of photons.
Quantum correlation cost of the weak measurement
Zhang, Jun; Wu, Shao-xiong; Yu, Chang-shui
2014-12-15
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.
Measuring and modeling correlations in multiplex networks
NASA Astrophysics Data System (ADS)
Nicosia, Vincenzo; Latora, Vito
2015-09-01
The interactions among the elementary components of many complex systems can be qualitatively different. Such systems are therefore naturally described in terms of multiplex or multilayer networks, i.e., networks where each layer stands for a different type of interaction between the same set of nodes. There is today a growing interest in understanding when and why a description in terms of a multiplex network is necessary and more informative than a single-layer projection. Here we contribute to this debate by presenting a comprehensive study of correlations in multiplex networks. Correlations in node properties, especially degree-degree correlations, have been thoroughly studied in single-layer networks. Here we extend this idea to investigate and characterize correlations between the different layers of a multiplex network. Such correlations are intrinsically multiplex, and we first study them empirically by constructing and analyzing several multiplex networks from the real world. In particular, we introduce various measures to characterize correlations in the activity of the nodes and in their degree at the different layers and between activities and degrees. We show that real-world networks exhibit indeed nontrivial multiplex correlations. For instance, we find cases where two layers of the same multiplex network are positively correlated in terms of node degrees, while other two layers are negatively correlated. We then focus on constructing synthetic multiplex networks, proposing a series of models to reproduce the correlations observed empirically and/or to assess their relevance.
Telomere length measurement by a novel Luminex-based assay: a blinded comparison to Southern blot
Pierce, Brandon L; Jasmine, Farzana; Roy, Shantanu; Zhang, Chenan; Aviv, Abraham; Hunt, Steven C; Ahsan, Habibul; Kibriya, Muhammad G
2016-01-01
Telomere length (TL) is a potential biomarker of aging and age-related disease risk. We recently published a novel Luminex-based method for high-throughput, low-cost TL measurement. Here we describe a blinded comparison of the Luminex method to Southern blot, the most precise TL measurement method. Luminex and Southern blot measurements for the same 50 DNA samples were taken in two independent laboratories; each sample was measured twice, several months apart. The inter-assay CV for Luminex ranged from 5.5 to 9.1 (depending on CV estimation method), and Southern blot CV from 1.0 to 1.7. Both measures were inversely associated with age. The correlation between the repeated measurements was 0.66 for Luminex and 0.97 for Southern blot. The correlation between Southern blot and Luminex was 0.65 in round 1 and 0.75 in round 2, and the relationship showed no evidence of non-linearity. Our results demonstrate that the Luminex assay is a valid and reproducible method for high-throughput TL measurement. The Luminex assay involves no DNA amplification, which may make Luminex an attractive alternative to PCR-based TL measurement. PMID:27186324
Titin isoform size is not correlated with thin filament length in rat skeletal muscle
Greaser, Marion L.; Pleitner, Jonathan M.
2014-01-01
The mechanisms controlling thin filament length (TFL) in muscle remain controversial. It was recently reported that TFL was related to titin size, and that the latter might be involved in TFL determination. Titin plays several crucial roles in the sarcomere, but its function as it pertains to the thin filament has not been explored. We tested this relationship using several muscles from wild type rats and from a mutant rat model (Greaser et al., 2008) which results in increased titin size. Myofibrils were isolated from skeletal muscles [extensor digitorum longus (EDL), external oblique (EO), gastrocnemius (GAS), longissimus dorsi (LD), psoas major (PM), and tibialis anterior(TA)] using both adult wild type (WT) and homozygous mutant (HM) rats (n = 6 each). Phalloidin and antibodies against tropomodulin-4 (Tmod-4) and nebulin's N-terminus were used to determine TFL. The WT rats studied express skeletal muscle titin sizes ranging from 3.2 to 3.7 MDa, while the HM rats express a giant titin isoform sized at 3.8 MDa. No differences in phalloidin based TFL, nebulin distance, or Tmod distance were observed across genotypes. However, the HM rats demonstrated a significantly increased (p < 0.01) rest sarcomere length relative to the WT phenotype. It appears that the increased titin size, predominantly observed in HM rats' middle Ig domain, allows for increased extensibility. The data indicates that, although titin performs many sarcomeric functions, its correlation with TFL and structure could not be demonstrated in the rat. PMID:24550844
Analysis of factors important for measurements of focal length of optical systems
NASA Astrophysics Data System (ADS)
Pokorný, P.; Opat, J.; Mikš, A.; Novák, J.; Novák, P.
2015-09-01
A focal length is a basic optical characteristic of an optical system. Thus, it is important to be able to measure this value for a given optical system very accurately in practice. At present there exist various physical principles of the focal length measurement which can achieve a different measurement accuracy. In our work we analyse several methods of measurement of the focal length with respect to factors, which are important for a measurement accuracy. The analysis is performed on examples.
Correlation of interannual length-of-day variation with El Nino/Southern Oscillation, 1972-1986
NASA Technical Reports Server (NTRS)
Chao, B. Fong
1988-01-01
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.
Suetterlin, Daniel; Erni, Daniel; Schlott, Volker; Sigg, Hans; Jaeckel, Heinz; Murk, Axel
2010-10-15
A spatial, electro-optical autocorrelation (EOA) interferometer using the vertically polarized lobes of coherent transition radiation (CTR) has been developed as a single-shot electron bunch length monitor at an optical beam port downstream the 100 MeV preinjector LINAC of the Swiss Light Source. This EOA monitor combines the advantages of step-scan interferometers (high temporal resolution) [D. Mihalcea et al., Phys. Rev. ST Accel. Beams 9, 082801 (2006) and T. Takahashi and K. Takami, Infrared Phys. Technol. 51, 363 (2008)] and terahertz-gating technologies [U. Schmidhammer et al., Appl. Phys. B: Lasers Opt. 94, 95 (2009) and B. Steffen et al., Phys. Rev. ST Accel. Beams 12, 032802 (2009)] (fast response), providing the possibility to tune the accelerator with an online bunch length diagnostics. While a proof of principle of the spatial interferometer was achieved by step-scan measurements with far-infrared detectors, the single-shot capability of the monitor has been demonstrated by electro-optical correlation of the spatial CTR interference pattern with fairly long (500 ps) neodymium-doped yttrium aluminum garnet (Nd:YAG) laser pulses in a ZnTe crystal. In single-shot operation, variations of the bunch length between 1.5 and 4 ps due to different phase settings of the LINAC bunching cavities have been measured with subpicosecond time resolution.
Understanding the amplitudes of noise correlation measurements
Tsai, Victor C.
2011-01-01
Cross correlation of ambient seismic noise is known to result in time series from which station-station travel-time measurements can be made. Part of the reason that these cross-correlation travel-time measurements are reliable is that there exists a theoretical framework that quantifies how these travel times depend on the features of the ambient noise. However, corresponding theoretical results do not currently exist to describe how the amplitudes of the cross correlation depend on such features. For example, currently it is not possible to take a given distribution of noise sources and calculate the cross correlation amplitudes one would expect from such a distribution. Here, we provide a ray-theoretical framework for calculating cross correlations. This framework differs from previous work in that it explicitly accounts for attenuation as well as the spatial distribution of sources and therefore can address the issue of quantifying amplitudes in noise correlation measurements. After introducing the general framework, we apply it to two specific problems. First, we show that we can quantify the amplitudes of coherency measurements, and find that the decay of coherency with station-station spacing depends crucially on the distribution of noise sources. We suggest that researchers interested in performing attenuation measurements from noise coherency should first determine how the dominant sources of noise are distributed. Second, we show that we can quantify the signal-to-noise ratio of noise correlations more precisely than previous work, and that these signal-to-noise ratios can be estimated for given situations prior to the deployment of seismometers. It is expected that there are applications of the theoretical framework beyond the two specific cases considered, but these applications await future work.
Finite-size effects of correlation lengths in planar uniaxial ferromagnets
NASA Astrophysics Data System (ADS)
Abraham, D. B.; Parry, A. O.; Upton, P. J.
1995-06-01
The finite-size structure of two-point correlation functions is studied using the bubble model applied to the two-dimensional Ising model at subcritical temperatures in a small bulk field H wrapped around a cylinder with a circumference of M lattice sites. Particular emphasis is placed on a crossover occurring in the mass gap at ||H||=H× corresponding to an ``avoided level crossing'' in the second and third eigenvalues of the transfer matrix. It is argued that this crossover occurs because the class of bubble determining the behavior of correlation functions changes from a single connected closed loop for ||H||>H× to two disconnected closed loops encircling the cylinder for 0<||H||
Eddy Correlation Flux Measurement System (ECOR) Handbook
Cook, DR
2011-01-31
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.
Knight, Rosemary J.; Irving, James D.; Tercier, Paulette; Freeman, Eugene J.; Murray, Christopher J.; Rockhold, Mark L.
2007-11-08
Surface-based ground-penetrating radar data were collected at the Hanford Site in Washington, U.S.A. to assess the use of radar reflection images as a means of quantifying the spatial variability of subsurface water content. Available at the selected test site were two sets of water content data derived from neutron probe measurements that had been made to a depth of ~18 m in 32 wells. The comparison of probe-derived water content data, synthetic radar data, and the acquired radar data indicated a good correspondence between the changes in probe-derived water content and the location of reflections in the radar data. Geostatistical analysis was conducted on the two sets of probe-derived water content values and the amplitudes of the reflections in the radar reflection image to determine the horizontal correlation length of water content. The experimental semivariograms for the water content data were fit with a single exponential model with a correlation length of 10 m. The semivariogram for the radar data was fit with a nested structure containing a dominant long-range structure with a correlation length of 14 m, and a smaller-scale structure with a correlation length of 0.3 m. Quantifying the scale triplet – the spacing, extent, and support – for the two forms of measurement provided a framework for comparing and assessing the derived correlation structures.
NASA Astrophysics Data System (ADS)
Brock, Ben W.; Willis, Ian C.; Sharp, Martin J.
Spatial and temporal variations in aerodynamic roughness length (z0) on Haut Glacier d'Arolla, Switzerland, during the 1993 and 1994 ablation seasons are described, based on measurements of surface microtopography. The validity of the microtopographic z0 measurements is established through comparison with independent vertical wind profile z0 measurements over melting snow, slush and ice. The z0 variations are explained through correlation and regression analyses, using independent measurements of meteorological and surface variables, and parameterizations are developed to calculate z0 variations for use in surface energy-balance melt models. Several independent variables successfully explain snow z0 variation through their correlation with increasing surface roughness, caused by ablation hollow formation, during snowmelt. Non-linear parameterizations based on either accumulated melt or accumulated daily maximum temperatures since the most recent snowfall explain over 80% of snow z0 variation. The z0 following a fresh snowfall on an ice surface is parameterized based on relationships with the underlying ice z0, snow depth and accumulated daily maximum temperatures. None of the independent variables were able to successfully explain ice z0 variation. Although further comparative studies are needed, the results lend strong support to the microtopographic technique of measuring z0 over melting glacier surfaces.
Boddum, Kim; Hansen, Mathias Hvidtfelt; Jennum, Poul Jørgen; Kornum, Birgitte Rahbek
2016-01-01
The hypocretin/orexin neuropeptides (hcrt) are key players in the control of sleep and wakefulness evidenced by the fact that lack of hcrt leads to the sleep disorder Narcolepsy Type 1. Sleep disturbances are common in mood disorders, and hcrt has been suggested to be poorly regulated in depressed subjects. To study seasonal variation in hcrt levels, we obtained data on hcrt-1 levels in the cerebrospinal fluid (CSF) from 227 human individuals evaluated for central hypersomnias at a Danish sleep center. The samples were taken over a 4 year timespan, and obtained in the morning hours, thus avoiding impact of the diurnal hcrt variation. Hcrt-1 concentration was determined in a standardized radioimmunoassay. Using biometric data and sleep parameters, a multivariate regression analysis was performed. We found that the average monthly CSF hcrt-1 levels varied significantly across the seasons following a sine wave with its peak in the summer (June-July). The amplitude was 19.9 pg hcrt/mL [12.8-26.9] corresponding to a 10.6% increase in midsummer compared to winter. Factors found to significantly predict the hcrt-1 values were day length, presence of snow, and proximity to the Christmas holiday season. The hcrt-1 values from January were much higher than predicted from the model, suggestive of additional factors influencing the CSF hcrt-1 levels such as social interaction. This study provides evidence that human CSF hcrt-1 levels vary with season, correlating with day length. This finding could have implications for the understanding of winter tiredness, fatigue, and seasonal affective disorder. This is the first time a seasonal variation of hcrt-1 levels has been shown, demonstrating that the hcrt system is, like other neurotransmitter systems, subjected to long term modulation. PMID:27008404
Boddum, Kim; Hansen, Mathias Hvidtfelt; Jennum, Poul Jørgen; Kornum, Birgitte Rahbek
2016-01-01
The hypocretin/orexin neuropeptides (hcrt) are key players in the control of sleep and wakefulness evidenced by the fact that lack of hcrt leads to the sleep disorder Narcolepsy Type 1. Sleep disturbances are common in mood disorders, and hcrt has been suggested to be poorly regulated in depressed subjects. To study seasonal variation in hcrt levels, we obtained data on hcrt-1 levels in the cerebrospinal fluid (CSF) from 227 human individuals evaluated for central hypersomnias at a Danish sleep center. The samples were taken over a 4 year timespan, and obtained in the morning hours, thus avoiding impact of the diurnal hcrt variation. Hcrt-1 concentration was determined in a standardized radioimmunoassay. Using biometric data and sleep parameters, a multivariate regression analysis was performed. We found that the average monthly CSF hcrt-1 levels varied significantly across the seasons following a sine wave with its peak in the summer (June—July). The amplitude was 19.9 pg hcrt/mL [12.8–26.9] corresponding to a 10.6% increase in midsummer compared to winter. Factors found to significantly predict the hcrt-1 values were day length, presence of snow, and proximity to the Christmas holiday season. The hcrt-1 values from January were much higher than predicted from the model, suggestive of additional factors influencing the CSF hcrt-1 levels such as social interaction. This study provides evidence that human CSF hcrt-1 levels vary with season, correlating with day length. This finding could have implications for the understanding of winter tiredness, fatigue, and seasonal affective disorder. This is the first time a seasonal variation of hcrt-1 levels has been shown, demonstrating that the hcrt system is, like other neurotransmitter systems, subjected to long term modulation. PMID:27008404
Small-Angle Neutron Scattering Studies of Magnetic Correlation Lengths in Nanoparticle Assemblies
NASA Astrophysics Data System (ADS)
Majetich, Sara
2009-03-01
Small-angle neutron scattering (SANS) measurements of ordered arrays of surfactant-coated magnetic nanoparticle reveal characteristic length scales associated with interparticle and intraparticle magnetic ordering. The high degree of uniformity in the monodisperse nanoparticle size and spacing leads to a pronounced diffraction peak and allows for a straightforward determination of these length scales [1]. There are notable differences in these length scales depending on the particle moment, which depends on the material (Fe, Co, Fe3O4) and diameter, and also on whether the metal particle core is surrounded by an oxide shell. For 8.5 nm particles containing an Fe core and thick Fe3O4 shell, evidence of a spin flop phase is seen in the magnetite shell when a field is applied , but not when the shell thickness is ˜0.5 nm [2]. 8.0 nm particles with an e-Co core and 0.75 nm CoO shell show no exchange bias effects while similar particles with a 2 nm thick shell so significant training effects below 90 K. Polarized SANS studied of 7 nm Fe3O4 nanoparticle assemblies show the ability to resolve the magnetization components in 3D. [4pt] [1] M. Sachan, C. Bonnoit, S. A. Majetich, Y. Ijiri, P. O. Mensah-Bonsu, J. A. Borchers, and J. J. Rhyne, Appl. Phys. Lett. 92, 152503 (2008). [0pt] [2] Yumi Ijiri, Christopher V. Kelly, Julie A. Borchers, James J. Rhyne, Dorothy F. Farrell, Sara A. Majetich, Appl. Phys. Lett. 86, 243102-243104 (2005). [0pt] [3] K. L. Krycka, R. Booth, J. A. Borchers, W. C. Chen, C. Conlon, T. Gentile, C. Hogg, Y. Ijiri, M. Laver, B. B. Maranville, S. A. Majetich, J. Rhyne, and S. M. Watson, Physica B (submitted).
NASA Astrophysics Data System (ADS)
Sofia, Giulia; Marinello, Francesco; Tarolli, Paolo
2014-10-01
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.
Generating nonclassical correlations without fully aligning measurements
Wallman, Joel J.; Bartlett, Stephen D.; Liang, Yeong-Cherng
2011-02-15
We investigate the scenario where spatially separated parties perform measurements in randomly chosen bases on an N-partite Greenberger-Horne-Zeilinger state. We show that without any alignment of the measurements, the observers will obtain correlations that violate a Bell inequality with a probability that rapidly approaches 1 as N increases and that this probability is robust against noise. We also prove that restricting these randomly chosen measurements to a plane perpendicular to a common direction will always generate correlations that violate some Bell inequality. Specifically, if each observer chooses their two measurements to be locally orthogonal, then the N observers will violate one of two Bell inequalities by an amount that increases exponentially with N. These results are also robust against noise and perturbations of each observer's reference direction from the common direction.
NASA Technical Reports Server (NTRS)
Venkatakrishnan, P.
1987-01-01
A physical length scale in the wavefront corresponding to the parameter (r sub 0) characterizing the loss in detail in a long exposure image is identified, and the influence of the correlation scale of turbulence as r sub 0 approaches this scale is shown. Allowing for the effect of 2-point correlations in the fluctuations of the refractive index, Venkatakrishnan and Chatterjee (1987) proposed a modified law for the phase structure function. It is suggested that the departure of the phase structure function from the 5/3 power law for length scales in the wavefront approaching the correlation scale of turbulence may lead to better 'seeing' at longer wavelengths.
Correlates of implicit cognitive line length representation in two-dimensional space.
Doty, Richard L; Koti, Ajay; O'Hara, Thomas A; Landy, Jeffrey; Shin, Christina; Silas, Jonathan
2014-10-01
Twenty-eight sex- and age-matched participants, half dextrals and half sinstrals, were instructed to move a pen-sized planometer three inches (7.6 cm) while blindfolded. Under separate trials, movements were made at four angles, towards and away from the body, and at two distances from the body (30 cm, 53 cm). Half were made with the right hand and half with the left hand. Line estimates increased in length across blocks of trials in a linear fashion and progressively overestimated the three-inch imagined criterion. Lines made moving towards the body were longer than those made moving away from the body, implying an egocentric frame of reference in making the estimates. Line estimates made at an oblique angle differed significantly from estimates made at other angles. No influences of sex, handedness, or the hand used in making the estimates were observed. The findings suggest that motoric estimates of line lengths made without visual cues-a unique measure of an implicit cognitive concept-are significantly altered by temporal and spatial factors, but not by sex or hemispheric laterality. PMID:25244556
PHENIX Measurements of Correlations at RHIC
NASA Astrophysics Data System (ADS)
Taranenko, Arkadiy
2016-01-01
Relativistic heavy-ion collisions provide a unique opportunity to study the expansion dynamics and the transport properties of the produced strongly interacting quark gluon plasma (QGP). This article reviews the recent soft physics results obtained via correlation measurements from the PHENIX experiment at RHIC: space-time extent of the pion emission source and azimuthal anisotropy of the particle production.
Quantum Correlations and the Measurement Problem
NASA Astrophysics Data System (ADS)
Bub, Jeffrey
2014-10-01
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.
[Compensation in leg length inequality with orthopedic shoe measures].
Meyer, P E; Petersen, D
1992-06-01
There are three different methods of compensating for differences in leg length. The first is the construction of special shoes, which is adequate for differences of up to about 3 cm. The heels can be either higher or lower, or a cork sole 5-10 mm thick can be incorporated, the shaft made higher, and supplementary features, such as aids to push-off, can also be implemented. The second method is the wearing of the classic orthopedic boot or shoe, in which the necessary compensation for the shorter leg is incorporated as a part of the orthopedic footwear. The third method is the construction of a shoe within a shoe, for which different designs have crystallized out for the five groups presented. All designs incorporate leather, the tried and tested material, next to the skin. Stabilizing components are made of fiberglass-reinforced synthetic resin or Thermoplast. New materials allow aesthetically acceptable orthopedic footwear. On average, such shoes are 25% lighter than conventional orthopedic boots. The stability and wear-resistance allow large perforations and open-toe designs, which has made it possible to solve the problem of ventilation. PMID:1508545
NASA Technical Reports Server (NTRS)
Johnson, R. A.; Wehrly, T.
1976-01-01
Population models for dependence between two angular measurements and for dependence between an angular and a linear observation are proposed. The method of canonical correlations first leads to new population and sample measures of dependence in this latter situation. An example relating wind direction to the level of a pollutant is given. Next, applied to pairs of angular measurements, the method yields previously proposed sample measures in some special cases and a new sample measure in general.
γ - γ Angular Correlation Measurements With GRIFFIN
NASA Astrophysics Data System (ADS)
Maclean, Andrew; Griffin Collaboration
2015-10-01
When an excited nuclear state emits successive γ-rays causing a γ - γ cascade an anisotropy is found in the spatial distribution of γ2 with respect to γ1. Defining the direction of γ1 as the z-axis, the intermediate level, in general will have an uneven distribution of m-states. This causes an anisotropy in the angular correlation of the second γ-ray with respect to the first. These angular correlations are expressed by the W (θ) that depends on numerical coefficients described by the sequence of spin-parity values for the nuclear states involved, the multipolarities and mixing ratios. Angular correlations can be used for the assignment of spins and parities for the nuclear states, and thus provide a powerful means to elucidate the structure of nuclei far from stability through β - γ - γ coincidence measurements. In order to explore the sensitivity of the new 16 clover-detector GRIFFIN γ-ray spectrometer at TRIUMF-ISAC to such γ - γ angular correlations, and to optimize its performance for these measurements we have studied a well known γ - γ cascade from 60Co decay through both experimental measurements and Geant4 simulation. Results will be shown in this talk. Work supported by the Canada Foundation for Innovation, the Natural Sciences and Engineering Research Council of Canada and the National Research Council of Canada.
Applications of Fluorescence Correlation Spectroscopy: Polydispersity Measurements.
Starchev; Buffle; Prez
1999-05-15
The method of histograms is applied to the determination of polydispersity of particles and molecules in solution from fluorescence correlation spectroscopy (FCS) data. This is an ill-posed problem, which can be overcome by using a common strategy for imposed regularization and constraint conditions. The method developed for evaluating the polydispersity is tested on both computer-generated correlation curves and real FCS data. The results obtained show that FCS measurements can be successfully used for the determination of polydispersity of suspensions, with an efficiency comparable to that of photon correlation spectroscopy (PCS). The advantage of FCS, however, is its better sensitivity to small particles (size <50 nm) and molecules in dilute solutions, as well as its better selectivity. The usefulness of FCS for environmental chemistry is discussed with regard to the obtained results. Copyright 1999 Academic Press. PMID:10222089
Measurement and analysis of sarcomere length in rat cardiomyocytes in situ and in vitro
Camelliti, P.; Bollensdorff, C.; Stuckey, D. J.; Picton, G.; Burton, R. A. B.; Clarke, K.; Kohl, P.
2010-01-01
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 μm (n = 167 measurements from N = 11 hearts) after correction for tissue orientation, which was significantly greater than that in isolated cells (1.71 μm, n = 346, N = 9 isolations) or ventricular slice preparations (1.79 μm, 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
Measurement of beat length in polarization-maintaining fibers with external forces method
NASA Astrophysics Data System (ADS)
Zhang, Hongxia; Wen, Guoqiang; Ren, Yaguang; Jia, Dagong; Liu, Tiegen; Zhang, Yimo
2012-05-01
Beat length is a key parameter for the polarization maintaining fibers (PMFs). Based on a white light scanning Michelson interferometer, the measurement of the phase beat length in PMFs employing the external force is presented. When the linearly polarized light propagates along the principal axis of the PMFs, the polarization coupling occurs at the force position of PMFs. The short and long length PMFs are measured respectively, furthermore, the uniformity of beat length measurement is tested. In the end, the advantages and the disadvantages of the method are discussed in detail.
Diffraction effects in length measurements by laser interferometry.
Sasso, C P; Massa, E; Mana, G
2016-03-21
High-accuracy dimensional measurements by laser interferometers require corrections because of diffraction, which makes the effective fringe-period different from the wavelength of a plane (or spherical) wave λ_{0}. By using a combined X-ray and optical interferometer as a tool to investigate diffraction across a laser beam, we observed wavelength variations as large as 10^{-8}λ_{0}. We show that they originate from the wavefront evolution under paraxial propagation in the presence of wavefront- and intensity-profile perturbations. PMID:27136842
Bunch Length and Impedance Measurements at SPEAR3
Corbett, W.J.; Cheng, W.X.; Fisher, A.S.; Huang, X.; /SLAC
2011-11-02
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.
Subpicometer Length Measurement Using Semiconductor Laser Tracking Frequency Gauge
NASA Technical Reports Server (NTRS)
Thapa, Rajesh; Phillips, James D.; Rocco, Emanuele; Reasenburg, Robert D.
2011-01-01
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.
Kunc, Vlastimil; Frame, Barbara J; Nguyen, Ba N.; TuckerIII, Charles L.; Velez-Garcia, Gregorio
2007-01-01
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.
A tool for measuring the bending length in thin wires
NASA Astrophysics Data System (ADS)
Lorenzini, M.; Cagnoli, G.; Cesarini, E.; Losurdo, G.; Martelli, F.; Piergiovanni, F.; Vetrano, F.; Viceré, A.
2013-03-01
Great effort is currently being put into the development and construction of the second generation, advanced gravitational wave detectors, Advanced Virgo and Advanced LIGO. The development of new low thermal noise suspensions of mirrors, based on the experience gained in the previous experiments, is part of this task. Quasi-monolithic suspensions with fused silica wires avoid the problem of rubbing friction introduced by steel cradle arrangements by directly welding the wires to silica blocks bonded to the mirror. Moreover, the mechanical loss level introduced by silica (ϕfs ˜ 10-7 in thin fused silica wires) is by far less than the one associated with steel. The low frequency dynamical behaviour of the suspension can be computed and optimized, provided that the wire bending shape under pendulum motion is known. Due to the production process, fused silica wires are thicker near the two ends (necks), so that analytical bending computations are very complicated. We developed a tool to directly measure the low frequency bending parameters of fused silica wires, and we tested it on the wires produced for the Virgo+ monolithic suspensions. The working principle and a set of test measurements are presented and explained.
A tool for measuring the bending length in thin wires.
Lorenzini, M; Cagnoli, G; Cesarini, E; Losurdo, G; Martelli, F; Piergiovanni, F; Vetrano, F; Viceré, A
2013-03-01
Great effort is currently being put into the development and construction of the second generation, advanced gravitational wave detectors, Advanced Virgo and Advanced LIGO. The development of new low thermal noise suspensions of mirrors, based on the experience gained in the previous experiments, is part of this task. Quasi-monolithic suspensions with fused silica wires avoid the problem of rubbing friction introduced by steel cradle arrangements by directly welding the wires to silica blocks bonded to the mirror. Moreover, the mechanical loss level introduced by silica (φfs ∼ 10(-7) in thin fused silica wires) is by far less than the one associated with steel. The low frequency dynamical behaviour of the suspension can be computed and optimized, provided that the wire bending shape under pendulum motion is known. Due to the production process, fused silica wires are thicker near the two ends (necks), so that analytical bending computations are very complicated. We developed a tool to directly measure the low frequency bending parameters of fused silica wires, and we tested it on the wires produced for the Virgo+ monolithic suspensions. The working principle and a set of test measurements are presented and explained. PMID:23556827
Young Children's Understandings of Length Measurement: Evaluating a Learning Trajectory
ERIC Educational Resources Information Center
Szilagyi, Janka; Clements, Douglas H.; Sarama, Julie
2013-01-01
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
Young Children's Understandings of Length Measurement: Evaluating a Learning Trajectory
ERIC Educational Resources Information Center
Szilagyi, Janka; Clements, Douglas H.; Sarama, Julie
2013-01-01
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…
Short range correlation length study in a single ZnO nanowire and its impact on phonon confinement
NASA Astrophysics Data System (ADS)
Shih, Po-Hsun; Cheng, Chia-Liang; Ma, Yuan-Ron; Wu, Sheng Yun
2016-03-01
We report the influence of the short range correlation length ζL on the optical properties of a single non-centrosymmetric ZnO nanowire. Confocal Raman scattering and one-dimension phonon confinement model were employed to investigate the phonon and geometric properties of a single ZnO nanowire. The local optical results reveal a red shift in the non-polar E2 high frequency mode and a short range correlation length of ζL = 10(2) nm is obtained due to the enhancement of the zinc diffusion during the ZnO domain nucleating.
Aerosol pattern correlation techniques of wind measurement
NASA Technical Reports Server (NTRS)
Eloranta, Edwin W.
1985-01-01
This paper reviews the current status of lidar image correlation techniques of remote wind measurement. It also examines the potential use of satellite borne lidar global wind measurements using this approach. Lidar systems can easily detect spatial variations in the volume scattering cross section of naturally occurring aerosols. Lidar derived RHI, PPI and range-time displays of aerosol backscatter have been extensively employed in the study of atmospheric structure. Descriptions of this type of data can be obtained in many references including Kunkel et al. (1977), Kunkel et al. (1980), Boers et al. (1984), Uthe et al. (1980), Melfi et al. (1985) and Browell et al. (1983). It is likely that the first space-borne lidars for atmospheric studies will observe aerosol backscatter to measure parameters such as boundary layer depth and cloud height. This paper examines the potential application of these relatively simple aerosol backscatter lidars to global wind measurements.
Estimating a Lagrangian Length Scale Using Measurements of CO2 in a Plant Canopy
NASA Astrophysics Data System (ADS)
Brown, Shannon E.; Warland, Jon S.; Santos, Eduardo A.; Wagner-Riddle, Claudia; Staebler, Ralf; Wilton, Meaghan
2013-04-01
Analytical Lagrangian equations capable of predicting concentration profiles from known source distributions offer the opportunity to calculate source/sink distributions through inverted forms of these equations. Inverse analytical Lagrangian equations provide a practical means of estimating source profiles using concentration and turbulence measurements. Uncertainty concerning estimates of the essentially immeasurable Lagrangian length scale ({{L}}), a key input, impedes the operational practicality of this method. The present study evaluates {{L}} within a corn canopy by using field measurements to constrain an analytical Lagrangian equation. Measurements of net CO2 flux, soil-to-atmosphere CO2 flux, and in-canopy profiles of CO2 concentration provided the information required to solve for {{L}} in a global optimization algorithm for 30-min time intervals. For days when the canopy was a strong CO2 sink, the optimization frequently located {{L}} profiles that follow a convex shape. A constrained optimization then fit the profile shape to a smooth sigmoidal equation. Inputting the optimized {{L}} profiles in the forward and inverse Lagrangian equations leads to strong correlations between measured and calculated concentrations and fluxes. Coefficients of the sigmoidal equation were specific to each 30-min period and did not scale with any measured variable. Plausible looking {{L}} profiles were associated with negative bulk Richardson number values. Once the canopy senesced, a simple eddy diffusivity profile sufficed to relate concentrations and sources in the analytical Lagrangian equations.
ERIC Educational Resources Information Center
van den Boer, Madelon; de Jong, Peter F.; Haentjens-van Meeteren, Marleen M.
2013-01-01
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
ERIC Educational Resources Information Center
van den Boer, Madelon; de Jong, Peter F.; Haentjens-van Meeteren, Marleen M.
2013-01-01
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…
Large-aperture laser differential confocal ultra-long focal length measurement and its system.
Zhao, Weiqian; Li, Zhigang; Qiu, Lirong; Ren, Huan; Shao, Rongjun
2015-06-29
A new laser differential confocal ultra-long focal length measurement (LDCFM) method is proposed with the capability to self-calibrate the reference lens (RL) focal length and the axial space between the test lens and RL. Using the property that the focus of laser differential confocal ultra-long focal length measurement system (LDCFS) precisely corresponds to the null point of the differential confocal axial intensity curve, the proposed LDCFM measures the RL focal length f(R)' by precisely identifying the positions of the focus and last surface of RL, measures the axial space d(0) between RL and test ultra-long focal length lens (UFL) by identifying the last surface of RL and the vertex of UFL last surface, and measures the variation l in focus position of LDCFS with and without test UFL, and then calculates the UFL focal length f(T)' by the above measured f(R)', d(0) and l. In addition, a LDCFS based on the proposed method is developed for a large aperture lens. The experimental results indicate that the relative uncertainty is less than 0.01% for the test UFL, which has an aperture of 610 mm and focal length of 31,000 mm. LDCFM provides a novel approach for the high-precision focal-length measurement of large-aperture UFL. PMID:26191747
Growcott, Abraham; Miller, Brian; Sirguey, Pascal; Slooten, Elisabeth; Dawson, Stephen
2011-07-01
Sperm whales (Physeter macrocephalus) emit short, broadband clicks which often include multiple pulses. The time interval between these pulses [inter-pulse interval (IPI)] represents the two-way time for a pulse to travel between the air sacs located at either end of the sperm whale's head. The IPI therefore, is a proxy of head length which, using an allometric relationship, can be used to estimate total body length. Previous studies relating IPI to an independent measure of length have relied on very small sample sizes and manual techniques for measuring IPI. Sound recordings and digital stereo photogrammetric measurements of 21 individuals were made off Kaikoura, New Zealand, and, in addition, archived recordings of whales measured with a previous photogrammetric system were reanalyzed to obtain a total sample size of 33 individuals. IPIs were measured automatically via cepstral analysis implemented via a software plug-in for pamguard, an open-source software package for passive acoustic monitoring. IPI measurements were highly consistent within individuals (mean CV=0.63%). The new regression relationship relating IPI (I) and total length (T) was found to be T=1.258I+5.736 (r(2)=0.77, p<0.001). This new regression provides a better fit than previous studies of large (> 11 m) sperm whales. PMID:21786922
Stan, Cristina; Cristescu, Monica Teodora; Luiza, Buimaga Iarinca; Cristescu, C P
2013-03-21
In the framework of multifractal detrended cross-correlation analysis, we investigate characteristics of series of length of coding and non-coding DNA sequences of some bacteria and archaea. We propose the use of a multifractal cross-correlation series that can be defined for any pair of equal lengths data sequences (or time series) and that can be characterized by the full set of parameters that are attributed to any time series. Comparison between characteristics of series of length of coding and non-coding DNA sequences and of their associated multifractal cross-correlation series for selected groups is used for the identification of class affiliation of certain bacteria and archaea. The analysis is carried out using the dependence of the generalized Hurst exponent on the size of fluctuations, the shape of the singularity spectra, the shape and relative disposition of the curves of the singular measures scaling exponent and the values of the associated parameters. Empirically, we demonstrate that the series of lengths of coding and non-coding sequences as well as the associated multifractal cross-correlation series can be approximated as universal multifractals. PMID:23313335
Measuring the lens focal length by laser reflection-confocal technology.
Yang, Jiamiao; Qiu, Lirong; Zhao, Weiqian; Shao, Rongjun; Li, Zhigang
2013-06-01
A laser reflection-confocal focal-length measurement (LRCFM) is proposed for the high-accuracy measurement of lens focal length. LRCFM uses the peak points of confocal response curves to precisely identify the lens focus and vertex of the lens last surface. LRCFM then accurately measures the distance between the two positions to determine the lens focal length. LRCFM uses conic fitting, which significantly enhances measurement accuracy by inhibiting the influence of environmental disturbance and system noise on the measurement results. The experimental results indicate that LRCFM has a relative expanded uncertainty of less than 0.0015%. Compared with existing measurement methods, LRCFM has high accuracy and a concise structure. Thus, LRCFM is a feasible method for high-accuracy focal-length measurements. PMID:23736337
Focal length measurement based on the wavefront difference method by a Fizeau interferometer.
Yang, Zhongming; Gao, Zhishan; Dou, Jiantai; Wang, Xinxing
2014-09-01
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
Eddy Correlation Flux Measurement System Handbook
Cook, D. R.
2016-01-01
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. The instruments used are: • a fast-response, three-dimensional (3D) wind sensor (sonic anemometer) to obtain the orthogonal wind components and the speed of sound (SOS) (used to derive the air temperature) • an open-path infrared gas analyzer (IRGA) to obtain the water vapor density and the CO2 concentration, and • an open-path infrared gas analyzer (IRGA) to obtain methane density and methane flux at one SGP EF and at the NSA CF. The ECOR systems are deployed at the locations where other methods for surface flux measurements (e.g., energy balance Bowen ratio [EBBR] systems) are difficult to employ, primarily at the north edge of a field of crops. A Surface Energy Balance System (SEBS) has been installed collocated with each deployed ECOR system in SGP, NSA, Tropical Western Pacific (TWP), ARM Mobile Facility 1 (AMF1), and ARM Mobile Facility 2 (AMF2). The surface energy balance system consists of upwelling and downwelling solar and infrared radiometers within one net radiometer, a wetness sensor, and soil measurements. The SEBS measurements allow the comparison of ECOR sensible and latent heat fluxes with the energy balance determined from the SEBS and provide information on wetting of the sensors for data quality purposes. The SEBS at one SGP and one NSA site also support upwelling and downwelling PAR measurements to qualify those two locations as Ameriflux sites.
ERIC Educational Resources Information Center
Tan-Sisman, Gulcin; Aksu, Meral
2012-01-01
"Knowing and doing measurement" is a fundamental competency in real life since measuring attributes of objects in appropriate units and using measuring tools assist students to quantify and understand the world. For this reason, the study of measurement has a special place in every mathematics curriculum. Among the domains of measurement, length
NASA Astrophysics Data System (ADS)
Knight, Rosemary J.; Irving, James D.; Tercier, Paulette; Freeman, Gene J.; Murray, Chris J.; Rockhold, Mark L.
Surface-based ground-penetrating radar data were collected at the Hanford Site in Washington, U.S.A. to assess the use of radar reflection images as a means of quantifying the spatial variability of subsurface water content. Available at the selected test site were two sets of water content data derived from neutron probe measurements that had been made to a depth of ˜18 m in 32 wells in 1980 and 1995. The comparison of probe-derived water content data, synthetic radar data, and the acquired radar data indicated a good correspondence between the changes in probe-derived water content and the location of reflections in the radar data. Geostatistical analysis was conducted on the two sets of probe-derived water content values and the amplitudes of the reflections in the radar reflection image to determine the horizontal correlation length of water content. The experimental semivariograms for the water content data were fit with a single exponential model with a correlation length of 10 m. The semivariogram for the radar data was fit with a nested structure containing a dominant long-range structure with a correlation length of 14 m, and a smaller-scale structure with a correlation length of 0.3 m. Quantifying the scale triplet—the spacing, extent, and support—for the two forms of measurement provided a framework for comparing and assessing the derived correlation structures. This approach also highlighted the importance of identifying methods for properly determining the scale of radar measurements required for the imaging of subsurface water content.
Eddy correlation measurements of submarine groundwater discharge
Crusius, J.; Berg, P.; Koopmans, D.J.; Erban, L.
2008-01-01
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.
Cosmological measurements with general relativistic galaxy correlations
NASA Astrophysics Data System (ADS)
Raccanelli, Alvise; Montanari, Francesco; Bertacca, Daniele; Doré, Olivier; Durrer, Ruth
2016-05-01
We investigate the cosmological dependence and the constraining power of large-scale galaxy correlations, including all redshift-distortions, wide-angle, lensing and gravitational potential effects on linear scales. We analyze the cosmological information present in the lensing convergence and in the gravitational potential terms describing the so-called ``relativistic effects'', and we find that, while smaller than the information contained in intrinsic galaxy clustering, it is not negligible. We investigate how neglecting them does bias cosmological measurements performed by future spectroscopic and photometric large-scale surveys such as SKA and Euclid. We perform a Fisher analysis using the CLASS code, modified to include scale-dependent galaxy bias and redshift-dependent magnification and evolution bias. Our results show that neglecting relativistic terms, especially lensing convergence, introduces an error in the forecasted precision in measuring cosmological parameters of the order of a few tens of percent, in particular when measuring the matter content of the Universe and primordial non-Gaussianity parameters. The analysis suggests a possible substantial systematic error in cosmological parameter constraints. Therefore, we argue that radial correlations and integrated relativistic terms need to be taken into account when forecasting the constraining power of future large-scale number counts of galaxy surveys.
ATLAS-3 correlative measurement opportunities with UARS and surface observations
NASA Technical Reports Server (NTRS)
Harrison, Edwin F.; Denn, Fred M.; Gibson, Gary G.
1995-01-01
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.
Mahakizadeh, S; -Ghoroghi, F Moghani; Moshkdanian, Gh; Mokhtari, T; Hassanzadeh, G
2016-03-01
Estimation of stature is an important issue, which is significantly considered in forensic anthropology. It will be difficult to predict the identification of an individual when only some parts of dead body are discovered following disasters or criminal events. The aim of this study was to assess the relationship between stature and upper limb and hand length in Iranian adults to generate regression formulae for stature estimation. Three anthropometric measurements; Stature, Upper Limb Length (ULL) and Hand Length (HL) were taken on subjects, comprising 142 male students (18-25 years) using standard measuring instruments. The data were analysed using SPSS 16. Then linear regression models were used to estimate stature. The results indicated a positive correlation between stature and upper limb and hand measurements. The correlation coefficient with upper limb length was r= 0.89 & p =0.0001 and with hand length was r= 0.78 & p =0.0001. In conclusion, we found a strong correlation between stature and upper limb and hand length. The regression analysis also showed that the Upper Limb Length give better prediction of stature compared to Hand length measurements. PMID:26795396
Experience of the fibrotest for measuring cotton fiber length and strength properties
Technology Transfer Automated Retrieval System (TEKTRAN)
The Fibrotest is a device developed by Textechno for measuring cotton fiber length and strength properties. The Fibrotest provides abundant information, including more than 20 length and strength parameters in absolute and relative modes, and displays fibrogram, load-elongation curve, and fiber bea...
Quantifying precision of in situ length and weight measurements of fish
Gutreuter, S.; Krzoska, D.J.
1994-01-01
We estimated and compared errors in field-made (in situ) measurements of lengths and weights of fish. We made three measurements of length and weight on each of 33 common carp Cyprinus carpio, and on each of a total of 34 bluegills Lepomis macrochirus and black crappies Pomoxis nigromaculatus. Maximum total lengths of all fish were measured to the nearest 1 mm on a conventional measuring board. The bluegills and black crappies (85–282 mm maximum total length) were weighed to the nearest 1 g on a 1,000-g spring-loaded scale. The common carp (415–600 mm maximum total length) were weighed to the nearest 0.05 kg on a 20-kg spring-loaded scale. We present a statistical model for comparison of coefficients of variation of length (Cl ) and weight (Cw ). Expected Cl was near zero and constant across mean length, indicating that length can be measured with good precision in the field. Expected Cw decreased with increasing mean length, and was larger than expected Cl by 5.8 to over 100 times for the bluegills and black crappies, and by 3 to over 20 times for the common carp. Unrecognized in situ weighing errors bias the apparent content of unique information in weight, which is the information not explained by either length or measurement error. We recommend procedures to circumvent effects of weighing errors, including elimination of unnecessary weighing from routine monitoring programs. In situ weighing must be conducted with greater care than is common if the content of unique and nontrivial information in weight is to be correctly identified.
DNA as a Metrology Standard for Length and Force Measurements with Optical Tweezers
Rickgauer, John Peter; Fuller, Derek N.; Smith, Douglas E.
2006-01-01
Optical tweezers have broad applications in studies of structures and processes in molecular and cellular biophysics. Use of optical tweezers for quantitative molecular-scale measurement requires careful calibration in physical units. Here we show that DNA molecules may be used as metrology standards for force and length measurements. Analysis of DNA molecules of two specific lengths allows simultaneous determination of all essential measurement parameters. We validate this biological-calibration method experimentally and with simulated data, and show that precisions in determining length scale factor (∼0.2%), length offset (∼0.03%), force scale factor (∼2%), and compliance of the traps (∼3%) are limited only by current measurement variation, much of which arises from polydispersity of the microspheres (∼2%). We find this procedure to be simpler and more convenient than previous methods, and suggest that it provides an easily replicated standard that can insure uniformity of measurements made in different laboratories. PMID:16963512
Slip length measurement of confined air flow on three smooth surfaces.
Pan, Yunlu; Bhushan, Bharat; Maali, Abdelhamid
2013-04-01
An experimental measurement of the slip length of air flow close to three different solid surfaces is presented. The substrate was driven by a nanopositioner moving toward an oscillating glass sphere glued to an atomic force microscopy (AFM) cantilever. A large separation distance was used to get more effective data. The slip length value was obtained by analyzing the amplitude and phase data of the cantilever. The measurements show that the slip length does not depend on the oscillation amplitude of the cantilever. Because of the small difference among the slip lengths of the three surfaces, a simplified analysis method was used. The results show that on glass, graphite, and mica surfaces the slip lengths are 98, 234, and 110 nm, respectively. PMID:23464759
Mori, Taizo; Sharma, Anshul; Hegmann, Torsten
2016-01-26
Chirality is a fundamental scientific concept best described by the absence of mirror symmetry and the inability to superimpose an object onto its mirror image by translation and rotation. Chirality is expressed at almost all molecular levels, from single molecules to supramolecular systems, and present virtually everywhere in nature. Here, to explore how chirality propagates from a chiral nanoscale surface, we study gold nanoparticles functionalized with axially chiral binaphthyl molecules. In particular, we synthesized three enantiomeric pairs of chiral ligand-capped gold nanoparticles differing in size, curvature, and ligand density to tune the chirality transfer from nanoscale solid surfaces to a bulk anisotropic liquid crystal medium. Ultimately, we are examining how far the chirality from a nanoparticle surface reaches into a bulk material. Circular dichroism spectra of the gold nanoparticles decorated with binaphthyl thiols confirmed that the binaphthyl moieties form a cisoid conformation in isotropic organic solvents. In the chiral nematic liquid crystal phase, induced by dispersing the gold nanoparticles into an achiral anisotropic nematic liquid crystal solvent, the binaphthyl moieties on the nanoparticle surface form a transoid conformation as determined by imaging the helical twist direction of the induced cholesteric phase. This suggests that the ligand density on the nanoscale metal surfaces provides a dynamic space to alter and adjust the helicity of binaphthyl derivatives in response to the ordering of the surrounding medium. The helical pitch values of the induced chiral nematic phase were determined, and the helical twisting power (HTP) of the chiral gold nanoparticles calculated to elucidate the chirality transfer efficiency of the binaphthyl ligand capped gold nanoparticles. Remarkably, the HTP increases with increasing diameter of the particles, that is, the efficiency of the chirality transfer of the binaphthyl units bound to the nanoparticle surface is diminished as the size of the particle is reduced. However, in comparison to the free ligands, per chiral molecule all tested gold nanoparticles induce helical distortions in a 10- to 50-fold larger number of liquid crystal host molecules surrounding each particle, indicating a significantly enhanced chiral correlation length. We propose that both the helicity and the chirality transfer efficiency of axially chiral binaphthyl derivatives can be controlled at metal nanoparticle surfaces by adjusting the particle size and curvature as well as the number and density of the chiral ligands to ultimately measure and tune the chiral correlation length. PMID:26735843
Optical fiber length measurement by external phase modulation type optical heterodyne reflectometry
Kimura, T.; Sawada, I.; Sasaki, N.; Noda, K. )
1989-04-01
A method for measuring optical fiber length is proposed and demonstrated experimentally with external phase modulation optical heterodyne reflectometry using a He-Ne laser as a light source. The system offers a simple length measuring method with satisfactory resolution. The reflected waves from fiber faults, if any, also can be detected by this method by observing two signals which occur at fault points and the fiber end.
Bunch length measurement at the Fermilab A0 photoinjector using a Martin-Puplett interferometer
Thurman-Keup, Randy; Fliller, Raymond Patrick; Kazakevich, Grigory; /Fermilab
2008-05-01
We present preliminary measurements of the electron bunch lengths at the Fermilab A0 Photoinjector using a Martin-Puplett interferometer on loan from DESY. The photoinjector provides a relatively wide range of bunch lengths through laser pulse width adjustment and compression of the beam using a magnetic chicane. We present comparisons of data with simulations that account for diffraction distortions in the signal and discuss future plans for improving the measurement.
Correlating Beauty and Two Measures of Pleasure.
Vale, Lauren; Gerger, Gernot; Leder, Helmut; Pelli, Denis
2015-01-01
When you look at your beauty and I look at mine, do we have the same feeling? Kant (1764) and Santayana (1896) say that the experience of beauty is pleasure, with qualifications. So we measure pleasure. Observers use Google Images to find an image that is beautiful to them. The observer is asked to look at that image and rate pleasure by continually adjusting the spread of two fingers to track the decaying pleasure they feel from the image. We record both the finger spread rating (on smartphone screen using our emotiontracker.net) and facial muscle activity (fEMG, facial electromyography of M. corrugator supercilii and M. zygomaticus major). We find a high correlation between the feeling of beauty (or liking) and fEMG and finger-rating responses. The rating correlation is 80% until 90 s after stimulus offset. This consistent finding across observers suggests that the two physiological responses, one overt and the other automatic, both track the pleasure of beauty. Meeting abstract presented at VSS 2015. PMID:26325934
NASA Astrophysics Data System (ADS)
Sofia, Giulia; Marinello, Francesco; Tarolli, Paolo
2014-05-01
Terraces represent an outstanding example that displays centuries of a ubiquitous human-Earth interaction, in a very specific and productive way, and they are a significant part of numerous local economies. They, in fact, optimise the local resources for agricultural purposes, but also exploit marginal landscapes, expanding local populations. The ubiquity, variety, and importance of terraces have motivated studies designed to understand them better both as cultural and ecological features, but also as elements that can deeply influence runoff generation and propagation, contributing to local instabilities, and triggering or aggravating land degradation processes. Their vulnerability in the face of fast-growing urban settlements and the changes in agricultural practices is also well known, prompting protection measures strongly supported by local communities, but also by national and international projects. This work explores the spatial heterogeneity of terraced landscapes, identifying a proper indicator able to discriminate a terraced landscape respect to a more natural one. Recognizing and characterizing terraced areas can offer important multi-temporal insights into issues such as agricultural sustainability, indigenous knowledge systems, human-induced impact on soil degradation or erosive and landslide processes, geomorphological and pedologic processes that influence soil development, and climatic and biodiversity changes. More in detail, the present work introduces a new morphological indicator from LiDAR, effectively implementable for the automatic characterization of terraced landscapes. For the study, we tested the algorithm for environments that differ in term of natural morphology and terracing system. Starting from a LiDAR Digital Terrain Models (DTM), we considered the local auto-correlation (~local self-similarity) of the slope, calculating the correlation between a slope patch and its surrounding areas. We define the resulting map as the "Slope Local Length of Auto-Correlation", or SLLAC map. The SLLAC map texture is characterized by the presence of peculiar elongated fibers that change depending on the landscape morphology, and on the type of terracing system. The differences in texture can be measured, and they can be used to discriminate terraced areas from more natural ones. Given the raising importance of these landscapes, the proposed procedure can offer an important and promising tool to explore the spatial heterogeneity of terraced sites.
Correlation measurements of fission-fragment properties
NASA Astrophysics Data System (ADS)
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
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 γ-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 γ-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 γ-rays and prompt neutrons due to their different time-of-flight.
Polarization gating enables sarcomere length measurements by laser diffraction in fibrotic muscle
NASA Astrophysics Data System (ADS)
Young, Kevin W.; Dayanidhi, Sudarshan; Lieber, Richard L.
2014-11-01
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.
Modified Sagnac interferometer for contact-free length measurement of a direct absorption cell.
Elandaloussi, Hadj; Rouillé, Christian; Marie-Jeanne, Patrick; Janssen, Christof
2016-03-10
Accurate path length measurements in absorption cells are recurrent requirements in quantitative molecular absorption spectroscopy. A new twin path laser interferometer for length measurements in a simple direct path absorption geometry is presented, along with a full uncertainty budget. The path in an absorption cell is determined by measuring the optical path length change due to the diminution of the refractive index when the cell originally filled with nitrogen gas is evacuated. The performance of the instrument based on a stabilized HeNe laser is verified by comparison with the results of direct mechanical length measurements of a roughly 45 mm long, specially designed absorption cell. Due to a resolution of about 1/300 of a HeNe fringe, an expanded (coverage factor k=2) uncertainty of 16 μm in the length measurement is achieved, providing an expanded relative uncertainty of 3.6·10^{-4} for the length of our test absorption cell. This value is about 8 times lower than what has been reported previously. The instrument will be useful for precision measurements of absorption cross sections of strong absorbers which require short light paths, such as ozone, halogen oxides, sulfur dioxide, and volatile organic compounds in the UV. PMID:26974791
The Length of a Pestle: A Class Exercise in Measurement and Statistical Analysis.
ERIC Educational Resources Information Center
O'Reilly, James E.
1986-01-01
Outlines the simple exercise of measuring the length of an object as a concrete paradigm of the entire process of making chemical measurements and treating the resulting data. Discusses the procedure, significant figures, measurement error, spurious data, rejection of results, precision and accuracy, and student responses. (TW)
ERIC Educational Resources Information Center
Subramaniam, Karthigeyan
2014-01-01
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…
ERIC Educational Resources Information Center
Subramaniam, Karthigeyan
2014-01-01
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
Pereira, Rafael Noschang; Karam, Francisco Consoli; Schwanke, Roberto Luís; Millman, Rubens; Foletto, Zilmar Minetto; Schwanke, Carla Helena Augustin
2016-01-01
Objective Preoperative estimation of the length and diameter of the semitendinosus (ST) and gracilis (G) tendons can assist surgeons and allow them to have the opportunity to choose alternative grafts. The aim of this study was to investigate whether anthropometric measurements such as height, weight and body mass index (BMI) or the patient's age and sex have any correlation with the thickness and the length of ST and G tendons. Methods Data were gathered from 64 patients who underwent the surgical procedure of anterior cruciate ligament reconstruction using the tendons of the ST and G muscles as grafts, between June 2012 and August 2013. Variables such as age, sex, weight, height, body mass index (BMI) and length and diameter of the tendons of the ST and G muscles were analyzed. Results There was a positive correlation between the height and total diameter of the quadruple graft (r = 0.254; p = 0.043), total length of the ST tendon (r = 0.450; p < 0.01), diameter of the double ST (r = 0.270; p = 0.031), triple ST (r = 0.347; p = 0.005), length of G tendon (r = 0.249; p = 0.047) and diameter of the double-G (r = 0.258; p = 0.039). However, age (r = -0.015; p = 0.908), weight (r = 0.165; p = 0.193) and body mass index (r = 0.012; p = 0.926) showed no correlation. Conclusion Our results show that age, weight and BMI did not correlate with the diameter and length of the graft, while the height had a positive correlation with the total length of the flexor tendons and the diameter of the graft from the flexors (ST and G). PMID:27069886
NASA Astrophysics Data System (ADS)
Monthus, Cécile; Garel, Thomas
2009-04-01
We consider the random wetting transition on the Cayley tree, i.e. the problem of a directed polymer on the Cayley tree in the presence of random energies along the left-most bonds. In the pure case, there exists a first-order transition between a localized phase and a delocalized phase, with a correlation length exponent νpure = 1. In the disordered case, we find that the transition remains first order, but that there exists two diverging length scales in the critical region: the typical correlation length diverges with the exponent νtyp = 1, whereas the averaged correlation length diverges with the bigger exponent νav = 2 and governs the finite-size scaling properties. We describe the relations with previously studied models that are governed by the same 'infinite disorder fixed point'. For the present model, where the order parameter is the contact density θL = la/L (defined as the ratio of the number la of contacts over the total length L ), the notion of 'infinite disorder fixed point' means that the thermal fluctuations of θL within a given sample become negligible on a large scale with respect to sample-to-sample fluctuations. We characterize the statistics over the samples of the free energy and of the contact density. In particular, exactly at criticality, we obtain that the contact density is not self-averaging but remains distributed over the samples in the thermodynamic limit, with the distribution {\\cal P}_{T_c}(\\theta) = 1/(\\pi \\sqrt{ \\theta (1-\\theta)}) .
Is it True That the Normal Valence-Length Correlation Is Irrelevant for Metal-Metal Bonds?
Singh, Vijay; Dixit, Mudit; Kosa, Monica; Major, Dan Thomas; Levi, Elena; Aurbach, Doron
2016-04-01
The most intriguing feature of metal-metal bonds in inorganic compounds is an apparent lack of correlation between the bond order and the bond length. In this study, we combine a variety of literature data obtained by quantum chemistry and our results based on the empirical bond valence model (BVM), to confirm for the first time the existence of a normal exponential correlation between the effective bond order (EBO) and the length of the metal-metal bonds. The difference between the EBO and the formal bond order is attributed to steric conflict between the (TM)n cluster (TM=transition metal) and its environment. This conflict, affected mainly by structural type, should cause high lattice strains, but electron redistribution around TM atoms, evident from the BVM calculations, results in a full or partial strain relaxation. PMID:26929001
In-process Measuring of Capacitance Per Unit Length for Single-core Electric Wires
NASA Astrophysics Data System (ADS)
Goldshtein, A. E.; Vavilova, G. V.; Mazikov, S. V.
2016-01-01
The paper describes technical in-process implementation of the electrical method to measure the electrical capacitance per unit length of a single core electric wire. The basic design values of the electro-capacitive measuring transducer are determined. The impact of changes in water conductivity on measurement results is analyzed. Techniques to offset from the impact of changes in water conductivity on the results of the electrical capacitance per unit length control based on indirect electrical conductivity measurement are considered. An appropriate correction of the conversion function is made.
Tyre contact length on dry and wet road surfaces measured by three-axial accelerometer
NASA Astrophysics Data System (ADS)
Matilainen, Mika; Tuononen, Ari
2015-02-01
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.
2011-01-01
Triplet repeats contribute to normal variation in behavioral traits and when expanded, cause brain disorders. While Huntington's Disease is known to be caused by a CAG triplet repeat in the gene Huntingtin, the effect of CAG repeats on brain function below disease threshold has not been studied. The current study shows a significant correlation between the CAG repeat length of the maternal and paternal allele in the Huntingtin gene among healthy subjects, suggesting assortative mating. PMID:22008211
Zhang, Hang; Hua, Chengyun; Ding, Ding; Minnich, Austin J
2015-01-01
Thermal conductivity measurements over variable lengths on nanostructures such as nanowires provide important information about the mean free paths (MFPs) of the phonons responsible for heat conduction. However, nearly all of these measurements have been interpreted using an average MFP even though phonons in many crystals possess a broad MFP spectrum. Here, we present a reconstruction method to obtain MFP spectra of nanostructures from variable-length thermal conductivity measurements. Using this method, we investigate recently reported length-dependent thermal conductivity measurements on SiGe alloy nanowires and suspended graphene ribbons. We find that the recent measurements on graphene imply that 70% of the heat in graphene is carried by phonons with MFPs longer than 1 micron. PMID:25764977
NASA Astrophysics Data System (ADS)
Zhang, Hang; Hua, Chengyun; Ding, Ding; Minnich, Austin J.
2015-03-01
Thermal conductivity measurements over variable lengths on nanostructures such as nanowires provide important information about the mean free paths (MFPs) of the phonons responsible for heat conduction. However, nearly all of these measurements have been interpreted using an average MFP even though phonons in many crystals possess a broad MFP spectrum. Here, we present a reconstruction method to obtain MFP spectra of nanostructures from variable-length thermal conductivity measurements. Using this method, we investigate recently reported length-dependent thermal conductivity measurements on SiGe alloy nanowires and suspended graphene ribbons. We find that the recent measurements on graphene imply that 70% of the heat in graphene is carried by phonons with MFPs longer than 1 micron.
Length measurement of the eye using a swept-source interferometer.
Al-Mohamedi, Haroun; Prinz, Andreas; Mieskes, Guido; Oltrup, Theo; Bende, Thomas
2014-02-01
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
Zhang, Hang; Hua, Chengyun; Ding, Ding; Minnich, Austin J.
2015-01-01
Thermal conductivity measurements over variable lengths on nanostructures such as nanowires provide important information about the mean free paths (MFPs) of the phonons responsible for heat conduction. However, nearly all of these measurements have been interpreted using an average MFP even though phonons in many crystals possess a broad MFP spectrum. Here, we present a reconstruction method to obtain MFP spectra of nanostructures from variable-length thermal conductivity measurements. Using this method, we investigate recently reported length-dependent thermal conductivity measurements on SiGe alloy nanowires and suspended graphene ribbons. We find that the recent measurements on graphene imply that 70% of the heat in graphene is carried by phonons with MFPs longer than 1 micron. PMID:25764977
Large-aperture ultra-long focal length measurement and its system by laser confocal techniques
NASA Astrophysics Data System (ADS)
Li, Zhigang; Qiu, Lirong; Zhao, Weiqian; Guo, Yongkui; Yuan, Quan
2015-09-01
A new laser confocal ultralong focal length measurement method (LCFM) is proposed with the capability to self-calibrate the reference lens (RL) focal length and the axial space between the test lens and the RL. Using the property that the focus of a laser confocal ultralong focal length measurement system (LCFS) precisely corresponds to the peak point of the confocal axial intensity curve, the proposed LCFM measures the RL focal length f\\text{R}\\prime by precisely identifying the positions of the focus and the last surface of the RL, measures the axial space d0 between the RL and the test ultra-long focal-length lens (UFL) by identifying the last surface of the RL and the vertex of the UFL last surface, measures the variation l in focus position of the LCFS with and without the test UFL, and then calculates the UFL focal length f\\text{T}\\prime using the above-measured f\\text{R}\\prime , d0, and l. Furthermore, the LCFM uses conic fitting, which obviously enhances the measurement accuracy by reducing the influences of random disturbances. In addition, an LCFS based on the proposed method is developed for large aperture lens. The experimental results indicate that the relative uncertainty is less than 0.015% for the test UFL, which has an aperture of 610?mm and a focal length of 31?000?mm. Compared with existing methods, the LCFM utilizes a concise structure and has good stability, making it especially suitable for practical engineering applications.
NASA Astrophysics Data System (ADS)
Mandadapu, Kranthi; Hudson, Alexander; Chandler, David
2015-03-01
Dynamical facilitation theory predicts the emergence of a non-trivial correlation length from the cooling process that transforms the reversible melt to the irreversible glass. A decrease in cooling rate produces an increase in correlation length, and an increase in correlation length coincides with an increase in stability and aging rate of the glass. Here, we present results from a large-scale non-equilibrium numerical simulation that provide the first demonstration of the emergent nonequilbrium correlation length for an atomistic model. The study also tests the ability of the theory to predict the value of the nonequilibrium length and its corresponding glass transition temperature in terms of material properties and cooling protocols. Nontrivial correlation length distinguishes melt from glass in a large-scale atomistic non-equilibrium simulation of a glass transition
Research on the measurement technology of effective arm length of swing arm profilometer
NASA Astrophysics Data System (ADS)
Chen, Lin; Jing, Hongwei; Wei, Zhongwei; Li, Jie; Cao, Xuedong
2014-09-01
When the swing arm profilometer(SAP) measuring the mirror, the effective arm length of SAP which haves an obvious influence on the measurement results of the mirror surface shape needs to be measured accurately. It requires the measurement uncertainty of the effective arm length to reach 10μm in order to meet the measurement requirements, in this paper, we present a kind of technology based on laser tracker to measure the effective arm length of SAP. When the swing arm rotates around the shaft axis of swing arm rotary stage, the probe and two laser tracker balls form three sections of circular arc around the shaft axis of swing arm rotary stage in space. Laser tracker tracks and measures the circular arcs of two laser tracker balls, the center coordinates of the circular plane of circular arc can be calculated by data processing. The linear equation that passes through the two center coordinates is the equation of the shaft axis of rotary stage, the vertical distance from the probe to the shaft axis of rotary stage which can be calculated refer to the equation from the point to the line is the effective arm length. After Matlab simulation, this measurement method can meet the measurement accuracy.
Su, H.-C.; Chang, H.-H.; Hu, C.-W.; Lee, C.-H.; Wu, Y.-H.; Chang, L. J.; Ioffe, A.; Kraan, H. T.
2010-01-05
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.
NASA Astrophysics Data System (ADS)
Su, Hui-Chia; Lee, Chih-Hao; Chang, Hsin-Ho; Wu, Yu-Han; Hu, Chih-Wei; Chang, L. J.; Ioffe, A.; Kraan, H. T.
2010-01-01
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 μ-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/cm2s 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 μm at virgin state and about 3.1 μm 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.
Absolute qPCR for measuring telomere length in bone marrow samples of plasma cell disorders.
Panero, Julieta; O'Callaghan, Nathan J; Fenech, Michael; Slavutsky, Irma
2015-02-01
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
Calibration for the errors resulted from aberration in long focal length measurement
NASA Astrophysics Data System (ADS)
Yao, Jiang; Luo, Jia; He, Fan; Bai, Jian; Wang, Kaiwei; Hou, Xiyun; Hou, Changlun
2014-09-01
In this paper, a high-accuracy calibration method for errors resulted from aberration in long focal length measurement, is presented. Generally, Gaussian Equation is used for calculation without consideration of the errors caused by aberration. However, the errors are the key factor affecting the accuracy in the measurement system of a large aperture and long focal length lens. We creatively introduce an effective way to calibrate the errors, with detailed analysis of the long focal length measurement based on divergent light and Talbot interferometry. Aberration errors are simulated by Zemax. Then, we achieve auto-correction with the help of Visual C++ software and the experimental results reveal that the relative accuracy is better than 0.01%.By comparing modified values with experimental results obtained in knife-edge testing measurement, the proposed method is proved to be highly effective and reliable.
NASA Astrophysics Data System (ADS)
Schödel, R.
2015-08-01
Traceability of length measurements to the international system of units (SI) can be realized by using optical interferometry making use of well-known frequencies of monochromatic light sources mentioned in the Mise en Pratique for the realization of the metre. At some national metrology institutes, such as Physikalisch-Technische Bundesanstalt (PTB) in Germany, the absolute length of prismatic bodies (e.g. gauge blocks) is realized by so-called gauge-block interference comparators. At PTB, a number of such imaging phase-stepping interference comparators exist, including specialized vacuum interference comparators, each equipped with three highly stabilized laser light sources. The length of a material measure is expressed as a multiple of each wavelength. The large number of integer interference orders can be extracted by the method of exact fractions in which the coincidence of the lengths resulting from the different wavelengths is utilized as a criterion. The unambiguous extraction of the integer interference orders is an essential prerequisite for correct length measurements. This paper critically discusses coincidence criteria and their validity for three modes of absolute length measurements: 1) measurements under vacuum in which the wavelengths can be identified with the vacuum wavelengths, 2) measurements under air in which the air refractive index is obtained from environmental parameters using an empirical equation, and 3) measurements under air in which the air refractive index is obtained interferometrically by utilizing a vacuum cell placed along the measurement pathway. For case 3), which corresponds to PTB’s Kösters-Comparator for long gauge blocks, the unambiguous determination of integer interference orders related to the air refractive index could be improved by about a factor of ten when an ‘overall dispersion value,’ suggested in this paper, is used as coincidence criterion.
Aubert, Geraldine; Hills, Mark; Lansdorp, Peter M
2012-02-01
Studies of telomeres and telomere biology often critically rely on the detection of telomeric DNA and measurements of the length of telomere repeats in either single cells or populations of cells. Several methods are available that provide this type of information and it is often not clear what method is most appropriate to address a specific research question. The major variables that need to be considered are the material that is or can be made available and the accuracy of measurements that is required. The goal of this review is to provide a comprehensive summary of the most commonly used methods and discuss the advantages and disadvantages of each. Methods that start with genomic DNA include telomere restriction fragment (TRF) length analysis, PCR amplification of telomere repeats relative to a single copy gene by Q-PCR or MMQPCR and single telomere length analysis (STELA), a PCR-based approach that accurately measures the full spectrum of telomere lengths from individual chromosomes. A different set of methods relies on fluorescent in situ hybridization (FISH) to detect telomere repeats in individual cells or chromosomes. By including essential calibration steps and appropriate controls these methods can be used to measure telomere repeat length or content in chromosomes and cells. Such methods include quantitative FISH (Q-FISH) and flow FISH which are based on digital microscopy and flow cytometry, respectively. Here the basic principles of various telomere length measurement methods are described and their strengths and weaknesses are highlighted. Some recent developments in telomere length analysis are also discussed. The information in this review should facilitate the selection of the most suitable method to address specific research question about telomeres in either model organisms or human subjects. PMID:21663926
Müllner, Tibor; Zankel, Armin; Lv, Yongqin; Svec, Frantisek; Höltzel, Alexandra; Tallarek, Ulrich
2015-10-21
A general, model-free, quantitative approach to the key morphological properties of a porous polymer monolith is presented. After 3D reconstruction, image-based analysis delivers detailed spatial and spatially correlated information on the structural heterogeneities in the void space and the polymer skeleton. Identified heterogeneities, which limit the monolith's performance in targeted applications, are traced back to the preparation process. PMID:26314251
Correlation of atmospheric optical turbulence and meteorological measurements
NASA Astrophysics Data System (ADS)
Vaucher, Gail M. Tirrell
1989-06-01
The correlation of meteorological events such as the jet stream, gravity waves and boundary layer circulation with the optical turbulence parameters, the transverse coherence length r sub o and the isoplanatic angle is essential for interpreting and forecasting imaging and laser systems performance. In support of the United States Air Force Relay Mirror Experiment, the Naval Postgraduate School performed a series of six site characterization measurements near Kihei, Maui, during August 1987 to July 1988. Spatial and temporal summaries of atmospheric events corresponding to the optical remote sensor data are presented using meteorological data from the National Weather Service Radiosonde Observation stations, synoptic charts, GOES-WEST infrared satellite images, and four Kihei, Maui rawinsonde datasets. To quantify the correlation between optical turbulence measurements and meteorological phenomena, four methods of calculating C square (T) from rawinsonde data were investigated. Results show that existing rawinsonde systems are inadequate for direct C square (T) calculation. However, moderate improvements in the vertical resolution, the temperature resolution and probe response time, will allow direct calculations of optical turbulence parameters from rawinsonde data.
Khatami, Saeid Reza; Galehdari, Hamid; Rasekh, Abdorrahman; Mombeini, Hayat; Konar, Elham
2015-01-01
Background The androgen receptor (AR) gene contains a polymorphic trinucleotide repeat that encodes a polyglutamine tract in its N-terminal transactivation domain (N- TAD). We aimed to find a correlation between the length of this polymorphic tract and azoospermia or oligozoospermia in infertile men living in Khuzestan, Iran. Materials and Methods In this case-control study during two years till 2010, we searched for microdeletions in the Y chromosome in 84 infertile male patients with normal karyotype who lived in Khuzestan Province, Southwest of Iran. All cases (n=12) of azoospermia or oligozoospermia resulting from Y chromosome microdele- tions were excluded from our study. The number of CAG repeats in exon 1 of the AR gene was determined in 72 patients with azoospermia or oligozoospermia and in 72 fertile controls, using the polymerase chain reaction (PCR) and polyacrylamide gel electrophoresis. Results Microdeletions were detected in 14.3% (n=12) patients suffering severe oligozoospermia. The mean CAG repeat length was 18.99 0.35 (range, 11-26) and 19.96 0.54 (range, 12-25) in infertile males and controls, respectively. Also in the infertile group, the most common allele was 19 (26.38%), while in controls, it was 25 (22.22%). Conclusion Y chromosome microdeletions could be one of the main reasons of male infertility living in Khuzestan Province, while there was no correlation between CAG length in AR gene with azoospermia or oligozoospermia in infertile men living in Khuzestan, Iran. PMID:26246877
Chen, Qianghua; Luo, Huifu; Wang, Sumei; Wang, Feng; Chen, Xinhua
2012-09-01
A measurement method based on interferometry with two different reference cavity lengths is presented and applied in air refractive index measurement in which the two cavity lengths and a laser wavelength are combined to generate two wavelength equivalents of cavity. Corresponding calculation equations are derived, and the optical path configuration is designed, which is inspired by the traditional synthetic wavelength method. Theoretical analyses indicate that the measurement uncertainty of the determined index of refraction is about 2.310(-8), which is mainly affected by the length precision of the long vacuum cavity and the ellipticity of polarization components of the dual-frequency laser, and the range of nonambiguity is 3.010(-5), which is decided by the length difference of the two cavities. Experiment results show that the accuracy of air refractive index measurement is better than 5.010(-8) when the laboratory conditions changes slowly. The merit of the presented method is that the classical refractometry can be also used without evacuation of the gas cavity during the experiment. Furthermore, the application of the traditional synthetic wavelength method may be extended by using the wavelength equivalents of cavity, any value of which can be easily acquired by changing cavity length rather than using actual wavelengths whose number is limited. PMID:22945157
Langemo, Diane; Spahn, James; Spahn, Thomas; Pinnamaneni, V Chowdry
2015-03-01
The study objective was to examine precision in wound measurement using a recently Food and Drug Administration-approved Scout (WoundVision, LLC, Indianapolis, Indiana) device to measure wound length (L) and width (W). Wound perimeter and a ruler measurement of L and W were also made. Images of 40 actual patient wounds were measured using the Scout device. All 3 techniques (length, width, perimeter) demonstrated acceptable within and between reader precision; however, the best precision was in wound perimeter measurement. PMID:25679463
Bunch Length Measurements at the JLab FEL Using Coherent Transition and Synchrotron Radiation
Evtushenko, P.; Coleman, J.; Jordan, K.; Klopf, J. Michael; Neil, G.; Williams, G. P.
2006-11-20
The JLab FEL is routinely operated with sub-picosecond bunches. The short bunch length is important for high gain of the FEL. Coherent transition radiation has been used for the bunch length measurements for many years. This diagnostic can be used only in the pulsed beam mode. It is our goal to run the FEL with CW beam and a 74.85 MHz micropulse repetition rate, which, with the 135 pC nominal bunch charge corresponds to the beam average current of 10 mA, Hence it is very desirable to have the possibility of making bunch length measurements when running CW beam with any micropulse frequency. We use a Fourier transform infrared (FTIR) interferometer, which is essentially a Michelson interferometer, to measure the spectrum of the coherent synchrotron radiation generated in the last dipole of the magnetic bunch compressor upstream of the FEL wiggler. This noninvasive diagnostic provides bunch length measurements for CW beam operation at any micropulse frequency. We also compare the measurements made with the help of the FTIR interferometer with data obtained using the Martin-Puplett interferometer. Results of the two diagnostics agree within 15 %. Here we present a description of the experimental setup, data evaluation procedure and results of the beam measurements.
Bunch Length Measurements at the JLab FEL Using Coherent Transition and Synchrotron Radiation
NASA Astrophysics Data System (ADS)
Evtushenko, P.; Coleman, J.; Jordan, K.; Klopf, J. Michael; Neil, G.; Williams, G. P.
2006-11-01
The JLab FEL is routinely operated with sub-picosecond bunches. The short bunch length is important for high gain of the FEL. Coherent transition radiation has been used for the bunch length measurements for many years. This diagnostic can be used only in the pulsed beam mode. It is our goal to run the FEL with CW beam and a 74.85 MHz micropulse repetition rate, which, with the 135 pC nominal bunch charge corresponds to the beam average current of 10 mA, Hence it is very desirable to have the possibility of making bunch length measurements when running CW beam with any micropulse frequency. We use a Fourier transform infrared (FTIR) interferometer, which is essentially a Michelson interferometer, to measure the spectrum of the coherent synchrotron radiation generated in the last dipole of the magnetic bunch compressor upstream of the FEL wiggler. This noninvasive diagnostic provides bunch length measurements for CW beam operation at any micropulse frequency. We also compare the measurements made with the help of the FTIR interferometer with data obtained using the Martin-Puplett interferometer. Results of the two diagnostics agree within 15 %. Here we present a description of the experimental setup, data evaluation procedure and results of the beam measurements.
Bunch Length Measurements at the JLab FEL Using Coherent Transition and Synchrotron Radiation
Pavel Evtushenko; James Coleman; Kevin Jordan; J. Michael Klopf; George Neil; Gwyn Williams
2006-05-01
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.
NASA Technical Reports Server (NTRS)
Flat, A.; Milnes, A. G.
1978-01-01
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.
Tricot, G; Saitoh, A; Takebe, H
2015-11-28
The structure of tin borophosphate glasses, considered for the development of low temperature sealing glasses or anode materials for Li-batteries, has been analysed at the intermediate length scale by a combination of high field standard and advanced 1D/2D nuclear magnetic resonance techniques. The nature and extent of B/P mixing were analysed using the (11)B((31)P) dipolar heteronuclear multiple quantum coherence NMR sequence and the data interpretation allowed (i) detecting the presence and analysing the nature of the B-O-P linkages, (ii) re-interpreting the 1D (31)P spectra and (iii) extracting the proportion of P connected to borate species. Interaction between the different borate species was analysed using the (11)B double quantum-simple quantum experiment to (i) investigate the presence and nature of the B-O-B linkage, (ii) assign the different borate species observed all along the composition line and (iii) monitor the borate network formation. In addition, (119)Sn static NMR was used to investigate the evolution of the chemical environment of the tin polyhedra. Altogether, the set of data allowed determining the structural units constituting the glass network and quantifying the extent of B/P mixing. The structural data were then used to explain the non-linear and unusual evolution of the glass transition temperature. PMID:26186677
An Imaging System for Automated Characteristic Length Measurement of Debrisat Fragments
NASA Technical Reports Server (NTRS)
Moraguez, Mathew; Patankar, Kunal; Fitz-Coy, Norman; Liou, J.-C.; Sorge, Marlon; Cowardin, Heather; Opiela, John; Krisko, Paula H.
2015-01-01
The debris fragments generated by DebriSat's hypervelocity impact test are currently being processed and characterized through an effort of NASA and USAF. The debris characteristics will be used to update satellite breakup models. In particular, the physical dimensions of the debris fragments must be measured to provide characteristic lengths for use in these models. Calipers and commercial 3D scanners were considered as measurement options, but an automated imaging system was ultimately developed to measure debris fragments. By automating the entire process, the measurement results are made repeatable and the human factor associated with calipers and 3D scanning is eliminated. Unlike using calipers to measure, the imaging system obtains non-contact measurements to avoid damaging delicate fragments. Furthermore, this fully automated measurement system minimizes fragment handling, which reduces the potential for fragment damage during the characterization process. In addition, the imaging system reduces the time required to determine the characteristic length of the debris fragment. In this way, the imaging system can measure the tens of thousands of DebriSat fragments at a rate of about six minutes per fragment, compared to hours per fragment in NASA's current 3D scanning measurement approach. The imaging system utilizes a space carving algorithm to generate a 3D point cloud of the article being measured and a custom developed algorithm then extracts the characteristic length from the point cloud. This paper describes the measurement process, results, challenges, and future work of the imaging system used for automated characteristic length measurement of DebriSat fragments.
Research on all fiber beat length measurement system for polarization-maintaining fibers
NASA Astrophysics Data System (ADS)
Peng, Li; Feng, Lishuang; Zhang, Xiaoqing; Hong, Lingfei
2010-12-01
Polarization-maintaining fiber (PMF) has attracted great attentions not only due to its ability to realize coherent optic communication with ultrahigh-capacity, but also because it can be widely employed in high-precise fiber-optic sensors and optic information processors, e.g., fiber-optic gyroscope and fiber-optic amperemeter. Distinct with common monomode optic fibers, additional birefringence is introduced in the PMF, minimizing the effect of mode coupling between two orthogonal polarization modes in optic fibers. Thus, light polarization can be maintained after long distance transmission in the PMF. However, beat-length, which reflects the characteristic of induced birefringence and evaluates the ability of polarization maintaining, is one of the most important parameters for PMF. Accurate measurement of PMF beat length becomes more and more important along with the expanding of its application field. The uniqueness of the measurement results determines the identity of PMF fabrication and the resolution of fiber-optic sensors. The existing measurement methods for PMF beat length are introduced first. Most testing setups are established by several individual components, which lead to complicated setup, inconvenient testing, and unsteady measurement. In this paper, a novel all fiber beat length measurement system is presented, where optic source, integrated optic modulator, stress apply structure, polarization detector, and polarization indicator of output light are included. The configuration and working principle of the whole system, and the designing and realization of each components, are addressed in the paper. Furthermore, the influence on measurement results by the relative direction between applied stress and principal axis of the optic fiber is analyzed. Moreover, optimized designs, including polarized light incidence, pressure apply, and precise movement systems, are performed, which ensure the identical pressure apply direction in the moving process. Finally, measurement of PMF samples is carried out on experimental setup. In comparison with the other existing system, due to its all fiber light incidence structure, the novel beat length measurement system represents great stability and high reliability.
Research on all fiber beat length measurement system for polarization-maintaining fibers
NASA Astrophysics Data System (ADS)
Peng, Li; Feng, Lishuang; Zhang, Xiaoqing; Hong, Lingfei
2011-05-01
Polarization-maintaining fiber (PMF) has attracted great attentions not only due to its ability to realize coherent optic communication with ultrahigh-capacity, but also because it can be widely employed in high-precise fiber-optic sensors and optic information processors, e.g., fiber-optic gyroscope and fiber-optic amperemeter. Distinct with common monomode optic fibers, additional birefringence is introduced in the PMF, minimizing the effect of mode coupling between two orthogonal polarization modes in optic fibers. Thus, light polarization can be maintained after long distance transmission in the PMF. However, beat-length, which reflects the characteristic of induced birefringence and evaluates the ability of polarization maintaining, is one of the most important parameters for PMF. Accurate measurement of PMF beat length becomes more and more important along with the expanding of its application field. The uniqueness of the measurement results determines the identity of PMF fabrication and the resolution of fiber-optic sensors. The existing measurement methods for PMF beat length are introduced first. Most testing setups are established by several individual components, which lead to complicated setup, inconvenient testing, and unsteady measurement. In this paper, a novel all fiber beat length measurement system is presented, where optic source, integrated optic modulator, stress apply structure, polarization detector, and polarization indicator of output light are included. The configuration and working principle of the whole system, and the designing and realization of each components, are addressed in the paper. Furthermore, the influence on measurement results by the relative direction between applied stress and principal axis of the optic fiber is analyzed. Moreover, optimized designs, including polarized light incidence, pressure apply, and precise movement systems, are performed, which ensure the identical pressure apply direction in the moving process. Finally, measurement of PMF samples is carried out on experimental setup. In comparison with the other existing system, due to its all fiber light incidence structure, the novel beat length measurement system represents great stability and high reliability.
Uesaka, Mitsuru; Maekawa, Akira; Tsujii, Ryosuke; Kinoshita, Kennichi; Atsushi, Yamazaki; Kobayashi, Kazuyuki; Shibata, Yukio; Kondo, Yasuhiro; Ohkubo, Takeru; Hosokai, Tomonao; Zhidkov, Alexei; Takahashi, Toshiharu
2006-11-27
Recently, several plasma cathodes at universities and institutes can generate a monoenergetic electron beam. LBL measured the bunch length by the CTR (Coherent Transition Radiation) interferometer to determine it as about 50 fs (FWHM). We are trying to carry out a single-shot measurement of the bunch length by a infrared polychromator. As the first step forward it, we measured the CTR spectra emitted at a 300microm-thick Ti foil by the electron beams from our plasma cathode. The laser parameters are 12 TW, 50fs, 3x1019W/cm2. He gas-jet is used and the electron density is 6x1019cm-3. By using the liquid He bolometer and several optical low-pass filter, we measured the spectra of the CTR. We can clearly classify the difference of the spectrum and bunch length for the monoenergetic and Maxwellian beams. The numerical analysis of the bunch elongation due to the energy spread confirms the experimental results. The bunch length of the monoenergetic beam is less than 100 fs at FWHM with about 10 pC per bunch, which is consistent with the PIC simulation. The next single-shot measurement with the FIR (Far-Ingfra-Red) polychomator and application to a pump-and-probe experiment for radiation chemsitry are also discussed.
Path-length measurement performance evaluation of polarizing laser interferometer prototype
NASA Astrophysics Data System (ADS)
Li, Yu-qiong; Luo, Zi-ren; Liu, He-shan; Dong, Yu-hui; Jin, Gang
2015-02-01
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.
Alignment and arm length measurement of the swing arm profilometer using a laser tracker
NASA Astrophysics Data System (ADS)
Jing, Hongwei; King, Christopher; Walker, David
2010-10-01
In this paper, we present the use of the laser tracker to aid the alignment of a Swing Arm Profilometer (SAP) and measure the length of the swinging arm, thus calibrating the operating radius of the SAP. The measurement uncertainty analysis is given. A laser tracker is used to align the SAP to ensure the path of the probe head passes through the rotary axis of the rotary table. By building the coordinate system by laser tracker measurement on the rotary table and measuring the swinging arc of the arm, we can determine whether the swinging path of the probe head passes through the rotary axis of the rotary table and perform the corresponding adjustment if necessary. A laser tracker is also used to measure the arm length, i.e. the length between the probe's ball centre and the rotation axis of the swinging arm. By placing a retroreflector or the tracker ball on the swinging arm and scanning the swinging path of the arm using the laser tracker, we can acquire the data of an arc and fit to determine the length of the probe head center to rotation axis of swinging arm, thus giving accurate SAP calibration data.
Lifetime and diffusion length measurements on silicon material and solar cells
NASA Technical Reports Server (NTRS)
Othmer, S.; Chen, S. C.
1978-01-01
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.
Determination of the minority carrier diffusion length of SnS using electro-optical measurements
NASA Astrophysics Data System (ADS)
Ramakrishna Reddy, K. T.; Nwofe, P. A.; Miles, R. W.
2013-05-01
The minority carrier diffusion length of the "absorber layer" in a solar cell is generally accepted to be one of the most important parameters that govern the performance of a solar cell device. In this work, thin films of SnS have been thermally evaporated onto cadmium sulphide/indium tin oxide/glass substrates, to fabricate heterojunction solar cell devices. The minority carrier diffusion length was determined for the first time for SnS layers using spectral response measurements in conjunction with optical absorption coefficient versus wavelength measurements. The minority carrier diffusion length was determined to be in the range 0.18-0.23 µm for the SnS/CdS devices investigated in this work.
NASA Astrophysics Data System (ADS)
Hahm, T. S.; Burrell, K. H.
1996-01-01
The radial correlation length of the turbulence responsible for transport can have a different gyroradius scaling in low (L)-mode and high (H)-mode plasmas due to E×B flow shear effects, as predicted by the two-point nonlinear analysis in general tokamak geometry [Phys. Plasmas 2, 1648 (1995)]. This difference offers a possible understanding of the recent ρ*-scan experiment results on DIII-D [Fusion Technol. 8, 441 (1985)] L-mode and H-mode plasmas [Phys. Plasmas 2, 2342 (1995)]. Within our model, thermal diffusivity in H-mode plasmas scales like gyro-Bohm, independent of the scaling in L-mode plasmas.
Zhang, Wenlu; Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026; Department of Physics and Astronomy, University of California, Irvine, California 92697 ; Lin, Zhihong; Fusion Simulation Center, Peking University, Beijing 100871
2013-10-15
Using the canonical perturbation theory, we show that the orbit-averaged theory only requires a time-scale separation between equilibrium and perturbed motions and verifies the widely accepted notion that orbit averaging effects greatly reduce the microturbulent transport of energetic particles in a tokamak. Therefore, a recent claim [Hauff and Jenko, Phys. Rev. Lett. 102, 075004 (2009); Jenko et al., ibid. 107, 239502 (2011)] stating that the orbit-averaged theory requires a scale separation between equilibrium orbit size and perturbation correlation length is erroneous.
Quantum information as a measure of multipartite correlation
NASA Astrophysics Data System (ADS)
Phoenix, Simon J. D.
2015-10-01
The mutual information has been successfully used as a measure of correlation strength between quantum systems, especially for bipartite systems. Here, we examine the use of this measure for multipartite quantum systems. For system of qubits, we find that the difference between `classical' and `quantum' regimes of correlation strength amounts to just 1 bit of information, at most. We show that the information content of a correlation can be expanded into correlations between pairwise components and demonstrate that in terms of this information-based measure of correlation the GHZ states are the only states that simultaneously optimise these pairwise correlations for systems of qubits.
NASA Astrophysics Data System (ADS)
Astashev, M. E.; Belosludtsev, K. N.; Kharakoz, D. P.
2014-05-01
One of the most accurate methods for measuring the compressibility of liquids is resonance measurement of sound velocity in a fixed-length interferometer. This method combines high sensitivity, accuracy, and small sample volume of the test liquid. The measuring principle is to study the resonance properties of a composite resonator that contains a test liquid sample. Ealier, the phase-locked loop (PLL) scheme was used for this. In this paper, we propose an alternative measurement scheme based on digital analysis of harmonic signals, describe the implementation of this scheme using commercially available data acquisition modules, and give examples of test measurements with accuracy evaluations of the results.
Failure of the Cross Correlation Measurement Technique
NASA Astrophysics Data System (ADS)
McGill, Ken; Ham, Katie; Schock, Kris
2014-03-01
The experiment involves creating a sound wave that propagates down a pipe with 8 transducers attached at equally spaced intervals of 0.01016 meters. The numerical method used to solve for the phase component, the Cross Correlation Method, creates a high correlation value, but the speed of sound varies immensely. The method involves a Fast Fourier Transform of the collected data, which is used to find the phase of the sound wave, and the slope of the position versus time graph, which is used to calculate the speed of sound. This high correlation values shows that the data is correct, but the numerical method for analyzing the data is incorrect. We would like to thank Dr. Ken McGill for all of his time, help, and guidance with this research project. We would also like to thank Georgia College and State University for both the resources and space necessary for this experiment.
Heltshe, Sonya L.; Borowitz, Drucy S.; Leung, Daniel H.; Ramsey, Bonnie; Mayer-Hamblett, Nicole
2014-01-01
Background CF infants often do not grow as expected which adversely affects later clinical outcomes, thus sensitive early measures of growth deficiency are important. This study compared attained growth for age with velocity standards to determine which better predicts growth deficits at 24 months of age. Methods Growth deficiency in infancy based on weight and length velocity, and attained growth was calculated for 1,992 infants in the US CF Foundation National Registry using the World Health Organization (WHO) and US growth standards. One, two, and three month increments were used for calculating velocity and pooled for each age interval. Sensitivity and specificity of early indicators to predict growth deficiency at 24 months were calculated. Results Observed prevalence of weight deficiency (<10th percentile) during the first year of life was 26.8% higher (95%CI=(25.6, 28.1%), p<0.001) on average when measured by attained weight for age than velocity. Attained weight for age at four months was a more sensitive predictor of diminished weight for age (<10th percentile) at 24 months (sensitivity=100%, 95%CI=(87, 100%)) than weight velocity (sensitivity=40%, 95%CI=(23, 59%)). Attained length at four months was more sensitive to detecting subsequent stunting (<10th percentile length for age) (77%, 95%CI=(62, 87%)) than length velocity (30%, 95%CI=(19, 45%)). Conclusions In CF infancy, attained weight or length are more sensitive than velocity-based definitions for predicting subsequent diminished growth. PMID:24917114
ERIC Educational Resources Information Center
Smith, John P., III; Males, Lorraine M.; Dietiker, Leslie C.; Lee, KoSze; Mosier, Aaron
2013-01-01
Extensive research has shown that elementary students struggle to learn the basic principles of length measurement. However, where patterns of errors have been documented, the origins of students' difficulties have not been identified. This study investigated the hypothesis that written elementary mathematics curricula contribute to the…
Sub-picosecond bunch length measurement at the TESLA test facility
NASA Astrophysics Data System (ADS)
Geitz, M.; Schmidt, G.; Schmüser, P.; Walter, G. v.
2000-05-01
Sub-picosecond electron bunches are required for the operation of future VUV and X-ray Free Electron Lasers. A streak camera, a Martin-Puplett interferometer and a longitudinal phase space rotation method have been applied at the TESLA Test Facility linac to measure electron bunch lengths.
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...
Understanding the influence of fiber length on the HVI measurement of cotton fiber strength
Technology Transfer Automated Retrieval System (TEKTRAN)
An earlier study confirmed the influence of cotton fiber length characteristics on the HVITM strength measurement and devised a quantitative correction factor to compensate for the effect. The current paper investigated the validity of two important assumptions utilised in the previous study. Firs...
Focal length measurement of a microlens-array by grating shearing interferometry.
Zhu, Xianchang; Hu, Song; Zhao, Lixin
2014-10-10
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
Roers, Friederike; Mürbe, Dirk; Sundberg, Johan
2009-07-01
Students admitted to the solo singing education at the University of Music Dresden, Germany have been submitted to a detailed physical examination of a variety of factors with relevance to voice function since 1959. In the years 1959-1991, this scheme of examinations included X-ray profiles of the singers' vocal tracts. This material of 132 X-rays of voice professionals was used to investigate different laryngeal morphological measures and their relation to vocal fold length. Further, the study aimed to investigate if there are consistent anatomical differences between singers of different voice classifications. The study design used was a retrospective analysis. Vocal fold length could be measured in 29 of these singer subjects directly. These data showed a strong correlation with the anterior-posterior diameter of the subglottis and the trachea as well as with the distance from the anterior contour of the thyroid cartilage to the anterior contour of the spine. These relations were used in an attempt to predict the 132 singers' vocal fold lengths. The results revealed a clear covariation between predicted vocal fold length and voice classification. Anterior-posterior subglottic-tracheal diameter yielded mean vocal fold lengths of 14.9, 16.0, 16.6, 18.4, 19.5, and 20.9mm for sopranos, mezzo-sopranos, altos, tenors, baritones, and basses, respectively. The data support the assumption that there are consistent anatomical laryngeal differences between singers of different voice classifications, which are of relevance to pitch range and timbre of the voice. PMID:18395418
Jones, Stephanie D; Wallman, James F; Byrne, Phillip G
2015-12-01
The phenotype-linked fertility hypothesis proposes that secondary sexual characters (SSCs) advertise a male's fertility to prospective mates. However, findings from empirical studies attempting to test this hypothesis are often ambivalent or even contradictory, and few studies have simultaneously evaluated how both morphological and behavioural SSCs relate to ejaculate characteristics. Males of the small hairy maggot blowfly, Chrysomya varipes, possess conspicuous foreleg ornaments and display highly stereotyped courtship behaviour. These traits are favoured by females during pre-copulatory mate choice, but it remains unknown whether they correlate with post-copulatory traits expected to influence male fertility. The aim of this study was to investigate whether male courtship and ornamentation correlate with testis size and sperm length in C. varipes. We found that males investing more in courtship had bigger testes, and males with more extensive foreleg ornamentation released sperm with longer tails. Based on the assumption that larger testes enable males to produce more sperm, and that sperm with longer tails have greater propulsive force, our findings suggest that more vigorous and more ornamented males may be more fertile. These findings lend support to the phenotype-linked fertility hypothesis. However, a complete test of this hypothesis will require evaluating whether testis size and sperm length influence male fertilisation ability, as well as female fecundity and/or fertility. PMID:26297128
Infrared Spectroscope for Electron Bunch-length Measurement: Heat Sensor Parameters Analysis
Domgmo-Momo, Gilles; /Towson U. /SLAC
2012-09-05
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.
Methods and apparatus for measuring a length of cable suspending a well logging tool in a borehole
Broding, R.A.
1986-07-01
A system is described for measuring depth from the mouth of a borehole to a well logging tool connected to one end of an electrically conductive cable suspended in the borehole comprising: means for applying an initial electrical time pulse signal to one end of the cable, whereby the initial electrical time pulse signal propagates the length of the cable to one end of the cable to the well logging tool connected to the other end of the cable; means for detecting at the mouth of the borehole, which is intermediate both ends of the cable, the passage of the initial electrical time pulse signal along the length of the cable; means for detecting at the mouth of the borehole a subsequent electrical time pulse propagating along the length of the cable reflected from the other end of the cable; means for determining a time interval between the detection of the initial electrical time pulse signal at the mouth of the borehole and the detection of the subsequent electrical time pulse signal at the mouth of the borehole; and means for correlating the time interval with the depth to which the well logging tool is suspended in the borehole as measured from the mouth of the borehole.
Taketani, Kaori; Yamada, Shigehito; Uwabe, Chigako; Okada, Tomohisa; Togashi, Kaori; Takakuwa, Tetsuya
2015-05-01
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 four 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 corresponded 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
NASA Astrophysics Data System (ADS)
Pitkin, M.
2015-08-01
There have been recent claims (Anderson et al., EPL, 110, 10002) of a 5.9 year periodicity in measurements of Newton's gravitational constant, $G$, which show a very strong correlation with observed periodic variations in the length of the day. I have used Bayesian model comparison to test this claim compared to other hypotheses that could explain the variation in the $G$ measurements. I have used the data from the initial claim, and from an updated set of compiled $G$ measurements that more accurately reflect the experimental dates, and find that a model containing an additional unknown Gaussian noise component is hugely favoured, by factors of $\\gtrsim e^{30}$, over two models allowing for a sinusoidal component.
Measurements of spin diffusion length in gold with point contact Andreev reflection spectroscopy
NASA Astrophysics Data System (ADS)
Faiz, Muhammad; Panguluri, Raghava; Balke, Benjamin; Wurmehl, Sabine; Felser, Claudia; Petukhov, Andre; Nadgorny, Boris
2008-03-01
Spin diffusion length, Ls, is of fundamental importance for spin dependent transport and spintronic devices. So far, most of the measurements of Ls in non-magnetic metals have been done in the lateral non-local geometry, with the chemical potential difference characterizing the spin imbalance. In our approach the spin diffusion length was measured directly with point contact Andreev reflection spectroscopy. A spin polarized current was injected from a ferromagnetic electrode, Co2Mn0.5Fe0.5Si Heulser alloy, into Au films of variable thickness. The spin current, which gradually decays with the increased thickness of the film, was measured with a superconducting Nb tip. We developed a phenomenological theory which allowed us to determine the values of Ls in such a system. We found Ls to be on the order of 250 nm at 4 K, comparable to the results obtained by other techniques. Similar results were obtained with a Gd single crystal.
Family-portraits for daphnids: scanning living individuals and populations to measure body length.
Agatz, Annika; Hammers-Wirtz, Monika; Gergs, Andre; Mayer, Tanja; Preuss, Thomas G
2015-08-01
A method has been developed and tested to determine the body length of living daphnids. The purpose of the method was the simple, accurate, repeatable, quick, and to the living organism, harmless measurement of body length of all individuals in a population to enhance the capability of observing population development over time. Generally, organisms are transferred to a petri dish and temporarily fixed by removing access medium. A picture of the petri dish is taken using an ordinary flatbed scanner. Pictures are manually analysed with purposely developed software. We found no significant impact of the method on either individual performance (growth and reproduction) or population development (abundance and structure) of daphnids in comparison to the previously used method for data gathering (sieving, counting and length measurement of a subsample via microscopy). The disadvantage of our method, an increased demand in time for picture analysis, is negligible compared to the advantages this method has. Data generated with the new method do represent the population structure more accurately than those data generated with the previously used method. Scanning organisms does also allow a retrospective quality control for generated data as pictures can securely be stored. The quality of the pictures is furthermore sufficient to include additional endpoints to the analysis (e.g., number and size of aborts, number and size of eggs in the brood pouch, spine length). Here, we present, test and discuss an alternative approach to automated image analysis for data gathering in single and multiple individual and species experiments. PMID:26048239
Is Socioeconomic Status Associated With Biological Aging as Measured by Telomere Length?
Robertson, Tony; Batty, G. David; Der, Geoff; Fenton, Candida; Shiels, Paul G.; Benzeval, Michaela
2013-01-01
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
Measuring limb length discrepancy using pelvic radiographs: the most reproducible method.
Heaver, Catriona; St Mart, Jean-Pierre; Nightingale, Peter; Sinha, Aabha; Davis, Edward T
2013-01-01
Leg length inequality following total hip replacement remains common. In an effort to reduce this occurrence, surgeons undertake pre-operative measurements, templating and use various forms of intraoperative measurements, including computer navigation. This study aims to delineate which measurement technique is most appropriate for measuring leg length inequality from a pelvic radiograph. Three observers took a total of 9600 measurements from 100 pelvic radiographs. Four lines were constructed on each of the radiographs, bisecting the acetabular teardrops, ischial spines, inferior sacroiliac joint and inferior obturator foramen. Measurements were taken from these lines to the most prominent medial point on the lesser trochanter and to the tip of the greater trochanter. The effect of pelvic positioning was also assessed using radiographs of a synthetic pelvis and femur. Intra-observer and inter-observer variability were calculated. Measuring from the inferior aspect of the ischial tuberosities to the most prominent medial point on the lesser trochanter appears to be the best method for measuring LLD however large error margin still exist, even when corrected for magnification errors. PMID:23934902
Adherence to Criteria for Transvaginal Ultrasound Imaging and Measurement of Cervical Length
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
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
Corrections to correlators in p{sub t} fluctuation measurements
Filip, Peter
2008-09-15
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.
Raschenberger, Julia; Lamina, Claudia; Haun, Margot; Kollerits, Barbara; Coassin, Stefan; Boes, Eva; Kedenko, Ludmilla; Köttgen, Anna; Kronenberg, Florian
2016-01-01
Measurement of telomere length is widely used in epidemiologic studies. Insufficient standardization of the measurements processes has, however, complicated the comparison of results between studies. We aimed to investigate whether DNA extraction methods have an influence on measured values of relative telomere length (RTL) and whether this has consequences for epidemiological studies. We performed four experiments with RTL measurement in quadruplicate by qPCR using DNA extracted with different methods: 1) a standardized validation experiment including three extraction methods (magnetic-particle-method EZ1, salting-out-method INV, phenol-chloroform-isoamyl-alcohol PCI) each in the same 20 samples demonstrated pronounced differences in RTL with lowest values with EZ1 followed by INV and PCI-isolated DNA; 2) a comparison of 307 samples from an epidemiological study showing EZ1-measurements 40% lower than INV-measurements; 3) a matching-approach of two similar non-diseased control groups including 143 pairs of subjects revealed significantly shorter RTL in EZ1 than INV-extracted DNA (0.844 ± 0.157 vs. 1.357 ± 0.242); 4) an association analysis of RTL with prevalent cardiovascular disease detected a stronger association with INV than with EZ1-extracted DNA. In summary, DNA extraction methods have a pronounced influence on the measured RTL-values. This might result in spurious or lost associations in epidemiological studies under certain circumstances. PMID:27138987
Raschenberger, Julia; Lamina, Claudia; Haun, Margot; Kollerits, Barbara; Coassin, Stefan; Boes, Eva; Kedenko, Ludmilla; Köttgen, Anna; Kronenberg, Florian
2016-01-01
Measurement of telomere length is widely used in epidemiologic studies. Insufficient standardization of the measurements processes has, however, complicated the comparison of results between studies. We aimed to investigate whether DNA extraction methods have an influence on measured values of relative telomere length (RTL) and whether this has consequences for epidemiological studies. We performed four experiments with RTL measurement in quadruplicate by qPCR using DNA extracted with different methods: 1) a standardized validation experiment including three extraction methods (magnetic-particle-method EZ1, salting-out-method INV, phenol-chloroform-isoamyl-alcohol PCI) each in the same 20 samples demonstrated pronounced differences in RTL with lowest values with EZ1 followed by INV and PCI-isolated DNA; 2) a comparison of 307 samples from an epidemiological study showing EZ1-measurements 40% lower than INV-measurements; 3) a matching-approach of two similar non-diseased control groups including 143 pairs of subjects revealed significantly shorter RTL in EZ1 than INV-extracted DNA (0.844 ± 0.157 vs. 1.357 ± 0.242); 4) an association analysis of RTL with prevalent cardiovascular disease detected a stronger association with INV than with EZ1-extracted DNA. In summary, DNA extraction methods have a pronounced influence on the measured RTL-values. This might result in spurious or lost associations in epidemiological studies under certain circumstances. PMID:27138987
d + Au hadron correlation measurements at PHENIX
Anne M. Sickles
2014-05-13
In these proceedings, we discuss recent results from d + Au collisions in PHENIX ridge related measurements and their possible hydrodynamic origin. We present the v_{2} at midrapidity and measurements of the pseudorapidity dependence of the ridge, distinguishing between the d-going and Au-going directions. We investigate the possible geometrical origin by comparing v_{2} in d + Au to that in p + Pb, Au + Au and Pb + Pb collisions. Future plans to clarify the role of geometry in small collision systems at RHIC are discussed.
Filippetto, D.; Sannibale, F.; Zolotorev, Max Samuil; Stupakov, G.V.; /SLAC
2008-01-24
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.
Ultrasonic measurement of stress in railroad wheels and in long lengths of welded rail
NASA Technical Reports Server (NTRS)
Clotfelter, W. N.; Risch, E. R.
1974-01-01
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.
Attribute-Based Time Series Cross-Correlation Measures
NASA Astrophysics Data System (ADS)
Cooper, G. R. J.
2016-05-01
Datasets are usually compared using cross-correlation, often using a moving window to calculate the correlation as a function of time or space. However, signals can be considered as being composed of sinusoids which possess amplitudes, frequencies and phases. All these three attributes can be computed at each point in time, and then used as the basis of a cross-correlation method. By using all the three measures of correlation together, their individual disadvantages can be minimised. By combining these measures with the continuous wavelet transform, information on the correlation as a function of wavelength can be obtained.
Hahm, T.S.; Burrell, K.H.
1996-01-01
The radial correlation length of the turbulence responsible for transport can have a different gyroradius scaling in low (L)-mode and high (H)-mode plasmas due to {bold E{times}B} flow shear effects, as predicted by the two-point nonlinear analysis in general tokamak geometry [Phys. Plasmas {bold 2}, 1648 (1995)]. This difference offers a possible understanding of the recent {rho}{sub {asterisk}}-scan experiment results on DIII-D [Fusion Technol. {bold 8}, 441 (1985)] L-mode and H-mode plasmas [Phys. Plasmas {bold 2}, 2342 (1995)]. Within our model, thermal diffusivity in H-mode plasmas scales like gyro-Bohm, independent of the scaling in L-mode plasmas. {copyright} {ital 1996 American Institute of Physics.}
Isotopic fractionation in proteins as a measure of hydrogen bond length.
McKenzie, Ross H; Athokpam, Bijyalaxmi; Ramesh, Sai G
2015-07-28
If a deuterated molecule containing strong intramolecular hydrogen bonds is placed in a hydrogenated solvent, it may preferentially exchange deuterium for hydrogen. This preference is due to the difference between the vibrational zero-point energy for hydrogen and deuterium. It is found that the associated fractionation factor Φ is correlated with the strength of the intramolecular hydrogen bonds. This correlation has been used to determine the length of the H-bonds (donor-acceptor separation) in a diverse range of enzymes and has been argued to support the existence of short low-barrier H-bonds. Starting with a potential energy surface based on a simple diabatic state model for H-bonds, we calculate Φ as a function of the proton donor-acceptor distance R. For numerical results, we use a parameterization of the model for symmetric O-H⋯O bonds [R. H. McKenzie, Chem. Phys. Lett. 535, 196 (2012)]. We consider the relative contributions of the O-H stretch vibration, O-H bend vibrations (both in plane and out of plane), tunneling splitting effects at finite temperature, and the secondary geometric isotope effect. We compare our total Φ as a function of R with NMR experimental results for enzymes, and in particular with an earlier model parametrization Φ(R), used previously to determine bond lengths. PMID:26233131
Isotopic fractionation in proteins as a measure of hydrogen bond length
NASA Astrophysics Data System (ADS)
McKenzie, Ross H.; Athokpam, Bijyalaxmi; Ramesh, Sai G.
2015-07-01
If a deuterated molecule containing strong intramolecular hydrogen bonds is placed in a hydrogenated solvent, it may preferentially exchange deuterium for hydrogen. This preference is due to the difference between the vibrational zero-point energy for hydrogen and deuterium. It is found that the associated fractionation factor Φ is correlated with the strength of the intramolecular hydrogen bonds. This correlation has been used to determine the length of the H-bonds (donor-acceptor separation) in a diverse range of enzymes and has been argued to support the existence of short low-barrier H-bonds. Starting with a potential energy surface based on a simple diabatic state model for H-bonds, we calculate Φ as a function of the proton donor-acceptor distance R. For numerical results, we use a parameterization of the model for symmetric O-H⋯O bonds [R. H. McKenzie, Chem. Phys. Lett. 535, 196 (2012)]. We consider the relative contributions of the O-H stretch vibration, O-H bend vibrations (both in plane and out of plane), tunneling splitting effects at finite temperature, and the secondary geometric isotope effect. We compare our total Φ as a function of R with NMR experimental results for enzymes, and in particular with an earlier model parametrization Φ(R), used previously to determine bond lengths.
Dogandžić, Tamara; Braun, David R.; McPherron, Shannon P.
2015-01-01
Blank size and form represent one of the main sources of variation in lithic assemblages. They reflect economic properties of blanks and factors such as efficiency and use life. These properties require reliable measures of size, namely edge length and surface area. These measures, however, are not easily captured with calipers. Most attempts to quantify these features employ estimates; however, the efficacy of these estimations for measuring critical features such as blank surface area and edge length has never been properly evaluated. In addition, these parameters are even more difficult to acquire for retouched implements as their original size and hence indication of their previous utility have been lost. It has been suggested, in controlled experimental conditions, that two platform variables, platform thickness and exterior platform angle, are crucial in determining blank size and shape meaning that knappers can control the interaction between size and efficiency by selecting specific core angles and controlling where fracture is initiated. The robustness of these models has rarely been tested and confirmed in context other than controlled experiments. In this paper, we evaluate which currently employed caliper measurement methods result in the highest accuracy of size estimations of blanks, and we evaluate how platform variables can be used to indirectly infer aspects of size on retouched artifacts. Furthermore, we investigate measures of different platform management strategies that control the shape and size of artifacts. To investigate these questions, we created an experimental lithic assemblage, we digitized images to calculate 2D surface area and edge length, which are used as a point of comparison for the caliper measurements and additional analyses. The analysis of aspects of size determinations and the utility of blanks contributes to our understanding of the technological strategies of prehistoric knappers and what economic decisions they made during process of blank production. PMID:26332773
Photon path length distributions for cloudy atmospheres from GOSAT satellite measurements
NASA Astrophysics Data System (ADS)
Kremmling, Beke; Penning de Vries, Marloes; Wagner, Thomas
2014-05-01
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.
Kim, Jin-Woo; Lee, Dong-Gi
2014-10-01
During the compression molding of fiber-reinforced plastic composites, there are two issues: one is separation of fiber and matrix because of the different flow state and fiber orientation. Due to separation and orientation, moldings become nonhomogeneous, and show anisotropy. Therefore, separation and orientation should be closely corresponded to molding condition and fiber structure. If fiber shows strong agglomeration, it increases the separation, but fiber orientation will be limited. That is, separation and orientation of fiber is closely related, and the relationship should be clearly defined. In this study, fiber content and length is varied for stacked laminates, and primary sheet is fabricated with thermal compression press. Primary sheet is heated and molded with 30-ton hydraulic press. Nonhomogeneity, one of indicators for separation, is measured from one-dimensional rectangular plate after compression. Orientation function is calculated using X-ray image on moldings and image scanner for processing imagery data. From the correlation between the separation and the orientation of fiber and matrix, the correlation coefficient is defined, and the impact of fiber length on the coefficient is evaluated. PMID:25942851
Colin, Rémy; Alsayed, Ahmed M; Gay, Cyprien; Abou, Bérengère
2015-12-14
Clusters of fast and slow correlated particles, identified as dynamical heterogeneities (DHs), constitute a central aspect of glassy dynamics. A key factor of the glass transition scenario is a significant increase of the cluster size ξ4 as the transition is approached. In need of easy-to-compute tools to measure ξ4, the dynamical susceptibility χ4 was introduced recently, and used in various experimental studies to probe DHs. Here, we investigate DHs in dense microgel suspensions using image correlation analysis, and compute both χ4 and the four-point correlation function G4. The spatial decrease of G4 provides a direct access to ξ4, which is found to grow significantly with increasing volume fraction. However, this increase is not captured by χ4. We show that the assumptions that validate the connection between χ4 and ξ4 are not fulfilled in our experiments. PMID:26412312
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
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
Method of glass melter electrode length measurement using time domain reflectometry (TDR)
Tarpley, James M.; Zamecnik, John R.
2000-02-28
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.
Phase-shifting algorithm inside an optical cavity for absolute length measurement.
Hibino, Kenichi
2016-02-10
Phase-shifting interferometry inside an optical cavity is useful for measuring the length of a cubic object and the diameter of a metal sphere. A new error-compensating phase-shifting algorithm is proposed, with which a spatially uniform phase error caused by nonlinear phase modulation can be eliminated. It is shown that the conventional algorithm design for harmonic analysis cannot compensate for this dc error unless the sampling weight definition is extended to a complex number. Specifically, a 3% quadratic nonlinearity in the phase modulation is found to yield a systematic error of 1.5 nm in the object length in many conventional algorithms. A new 13-frame algorithm is described that applies a modified discrete Fourier window and can reduce the dc error to less than 0.5 nm. PMID:26906383
Measurement and Correlation of Ice Accretion Roughness
NASA Technical Reports Server (NTRS)
Anderson, David N.; Hentschel, Daniel B.; Ruff, Gary A.
2003-01-01
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.
Bunch Length Measurements at the ATF Damping Ring in April 2000
Bane, K.L.F.; Naito, T.; Okugi, T.; Urakawa, J.; /KEK, Tsukuba
2005-12-19
We want to accurately know the energy spread and bunch length dependence on current in the ATF damping ring. One reason is to know the strength of the impedance: From the energy spread measurements we know whether or not we are above the threshold to the microwave instability, and from the energy spread and bunch length measurements we find out the extent of potential-well bunch lengthening (PWBL). Another reason for these measurements is to help in our understanding of the intra-beam scattering (IBS) effect in the ATF. The ATF as it is now, running below design energy and with the wigglers turned off, is strongly affected by IBS. To check for consistency with IBS theory of, for example, the measured vertical beam size, we need to know all dimensions of the beam, including the longitudinal one. But beyond this practical reason for studying IBS, IBS is currently a hot research topic at many accelerators around the world (see e.g. Ref. [1]), and the effect in actual machines is not well understood. Typically, when comparing theory with measurements fudge factors are needed to get agreement (see e.g. Ref. [1]). With its strong IBS effect, the ATF is an ideal machine for studying IBS, and an indispensable ingredient for this study is a knowledge of the longitudinal phase space of the beam. The results of earlier bunch lengthening measurements in the ATF can be found in Refs. [2]-[4]. Measurements of current dependent effects, especially bunch length measurements using a streak camera, can be difficult to perform accurately. For example, space charge in the camera itself can lead to systematic errors in the measurement results. It is important the results be accurate and reproducible. In the measurements of both December 1998[3] and December 1999[4], by using light filters, the authors first checked that space charge in the streak camera was not significant. And then the Dec 99 authors show that their results agree with those Dec 98, i.e. on the dates of the two measurements the results were reproducible. Since IBS is so strong in the ATF, in the Dec 99 measurements an attempt was made to estimate the impedance effect using the following method: First, from the form of the energy spread vs. current measurements it was concluded that the threshold to the microwave instability was beyond 2 mA. Then, by dividing the bunch length vs. current curve by the energy spread vs. current curve the effect of IBS was divided out, and PWBL was approximated. The assumption is that PWBL can be treated as a perturbation on top of IBS. The result was that this component of bunch lengthening was found to grow by 7-15% (depending on the rf voltage) between the currents of .5 mA and 2 mA, about a factor of 3 less than the total bunch length growth. The conclusion was that the inductive component of the impedance was small, in fact much smaller than had been concluded earlier in Ref. [2]. Electron machines generally run in a parameter regime where IBS is an insignificant effect, and impedance measurements and calculations have also normally been performed for machines where IBS is unimportant. To simplify the interpretation of the impedance from bunch length measurements, in April 2000 the energy spread and bunch length measurements of Dec 99 were repeated, but now with the beam on a linear (difference) coupling resonance, where the horizontal and vertical emittances were approximately equal. For this case the effect of IBS was expected to be very small. An energy spread vs. current measurement under such conditions will also allow us to more clearly see whether we reach the threshold to the microwave instability. As part of the April data taking we, in addition, repeated the earlier off-coupling measurements, in order to check the reproducibility of the earlier results. In this report we present and analyze this recent set of data, and compare it with the results of the earlier measurements, particularly those of Dec 99. The measurements and analysis of data in this report follow essentially the same procedure as was used in Ref. [4]. In the present report we will try to be relatively brief. The comparison of our results with IBS theory will be given in a following report. For more details about the measurement and analysis techniques presented in this report, the reader should consult Ref. [4].
NASA Astrophysics Data System (ADS)
Lysenko, V. G.; Kupko, V. S.; Makarevich, V. B.
2016-01-01
A trilateral comparison has been performed in the subject field of roundness measurement. The comparison was pilot by VNIIMS, Russia and took place between February 2014 and August 2014. The circulated standards were a roundness transfer standard in the form of a glass hemisphere and a magnification standard often referred to as a 'Flick' standard. Data from the roundness standard were processed using a Gaussian filter and a bandpass up to 50 undulations per revolution to provide a measured value of Roundness Deviation (RONt). For the magnification standard, data were also filtered and the fitted element was the circumscribed circle together with the deviation of the valleys (RONv). The results of comparisons show the correspondence of measurement uncertainties to the declared values and the compared measurement standards are equivalent. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
NASA Astrophysics Data System (ADS)
Rozler, Michael
It is clear that complete understanding of macroscopic properties of materials is impossible without a thorough knowledge of behavior at the smallest length scales. While the past 25 years have witnessed major advances in a variety of techniques that probe the nanoscale properties of matter, electrical transport measurements -- the heart of condensed matter research -- have lagged behind, never progressing beyond bulk measurements. This thesis describes a scanning tunneling potentiometry (STP) system developed to simultaneously map the transport-related electrochemical potential distribution of a biased sample along with its surface topography, extending electronic transport measurements to the nanoscale. Combining a novel sample biasing technique with a continuous current-nulling feedback scheme pushes the noise performance of the measurement to its fundamental limit - the Johnson noise of the STM tunnel junction. The resulting 130 nV voltage sensitivity allows us to spatially resolve local potentials at scales down to 2 nm, while maintaining atomic scale STM imaging, all at scan sizes of up to 15 microns. A mm-range two-dimensional coarse positioning stage and the ability to operate from liquid helium to room temperature with a fast turn-around time greatly expand the versatility of the instrument. Use of carefully selected model materials, combined with excellent topographic and voltage resolution has allowed us to distinguish measurement artifacts caused by surface roughness from true potentiometric features, a major problem in previous STP measurements. The measurements demonstrate that STP can produce physically meaningful results for homogeneous transport as well as non-uniform conduction dominated by material microstructures. Measurements of several physically interesting materials systems are presented as well, revealing new behaviors at the smallest length sales. The results establish scanning tunneling potentiometry as a useful tool for physics and materials science.
Method for high-accuracy multiplicity-correlation measurements
NASA Astrophysics Data System (ADS)
Gulbrandsen, K.; Søgaard, C.
2016-04-01
Multiplicity-correlation measurements provide insight into the dynamics of high-energy collisions. Models describing these collisions need these correlation measurements to tune the strengths of the underlying QCD processes which influence all observables. Detectors, however, often possess limited coverage or reduced efficiency that influence correlation measurements in obscure ways. In this paper, the effects of nonuniform detection acceptance and efficiency on the measurement of multiplicity correlations between two distinct detector regions (termed forward-backward correlations) are derived. An analysis method with such effects built in is developed and subsequently verified using different event generators. The resulting method accounts for acceptance and efficiency in a model-independent manner with high accuracy, thereby shedding light on the relative contributions of the underlying processes to particle production.
Visual Decisions in the Presence of Measurement and Stimulus Correlations.
Bhardwaj, Manisha; Carroll, Samuel; Ma, Wei Ji; Josić, Krešimir
2015-11-01
Humans and other animals base their decisions on noisy sensory input. Much work has been devoted to understanding the computations that underlie such decisions. The problem has been studied in a variety of tasks and with stimuli of differing complexity. However, how the statistical structure of stimuli, along with perceptual measurement noise, affects perceptual judgments is not well understood. Here we examine how correlations between the components of a stimulus-stimulus correlations-together with correlations in sensory noise, affect decision making. As an example, we consider the task of detecting the presence of a single or multiple targets among distractors. We assume that both the distractors and the observer's measurements of the stimuli are correlated. The computations of an optimal observer in this task are nontrivial yet can be analyzed and understood intuitively. We find that when distractors are strongly correlated, measurement correlations can have a strong impact on performance. When distractor correlations are weak, measurement correlations have little impact unless the number of stimuli is large. Correlations in neural responses to structured stimuli can therefore have a strong impact on perceptual judgments. PMID:26378875
Identification of source of oscillations in apparent sarcomere length measured by laser diffraction.
Burton, K; Huxley, A F
1995-01-01
The most widely used technique for dynamic estimates of sarcomere length in muscle is laser light diffraction. We have identified conditions under which artifactual oscillations can arise in apparent sarcomere length measured by this technique and report methods to reduce the effect. Altringham et al. (1984) first reported that the diffraction angle can exhibit one cycle of oscillation for each sarcomere length displacement of the illuminated portion of the fiber. We find that the amplitude of similar oscillations is strongly dependent on the intensity of light scattered from objects near the fiber and on the spacing between fiber and scatterer. The oscillations can be eliminated by minimizing scattered light and positioning the fiber a few millimeters from sources of scattering. A theoretical description shows that oscillations of this kind are expected from interference of scattered and diffracted light. Interference fringes were observed along the meridian of the pattern, and these moved during translation of either a fiber or a grating. The movement of fringes across the diffraction order shifts the centroid back and forth and, when associated with steady shortening, can give rise to "steps" and "pauses" in apparent striation spacing. Images FIGURE 1 FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 FIGURE 7 FIGURE 8 PMID:7647247
Measurements of Roughness Length and Displacement Heights in Model Urban Canopies
NASA Astrophysics Data System (ADS)
Rahman, Auvi; Huq, Pablo; Camelli, Fernando; UD-GMU Collaboration
2013-11-01
We present the results of roughness length and displacement height based on PIV velocity measurements in a water tunnel experiment of flow over idealized models of urban canopies. Experiments were conducted with large roughness elements of regular arrays of buildings of uniform height with aspect ratios of 1 and 3. Mean velocity profile above the canopy is described by the log law and a simple optimization procedure to compute the roughness length and displacement height has been developed. Laterally averaged values of displacement height d/H increase from 0 to 1 with plan area density λp of the urban canopy. In contrast, laterally averaged roughness height z0/H increases to a maximum value (as λf approaches a value of 0.2) and then decreases to zero. We present data for effective roughness heights (z0 + d)/H as a function of aspect ratio H/wb of buildings. This also reveals three categories of values: street canyon, building wake, and laterally averaged values. Measurements taken at the centerline of canyons form a lower bound on the effective roughness height whereas measurements behind building wakes form an upper bound. Laterally averaged values of friction velocity u*/UH varied inversely with the aspect ratio (UH is the mean velocity at the building height).
Measurement of Photon Path Length Distributions For Validation of Radiative Transfer Models
NASA Astrophysics Data System (ADS)
Scholl, T.; Nägele, U.; Funk, O.; Platt, U.; Pfeilsticker, K.; Lemke, H.; Quante, M.; Sievers, O.; Crewell, S.; Venema, V.
High resolution DOAS spectroscopy of the Oxygen A-band (760-780 nm) in zenith- scattered light is a powerful tool to infer path length distributions (PDF) of solar pho- tons transmitted to the ground. Solar photon PDF's thus provide information on mul- tiple scattering statistics of cloudy sky radiative transport (RT). When combining so- lar photon PDF's measurements with simultaneous RADAR measurements of the 3D cloud structure and radiometric measurements of the Liquid Water Path (LWP) effects of the 3-D cloud structure on the RT can be studied thoroughly. One strong indicator for 3-D effects on the cloudy sky RT is the investigation of the mean total photon path length (
Diffusion length measurement using the scanning electron microscope. [for silicon solar cell
NASA Technical Reports Server (NTRS)
Weizer, V. G.
1975-01-01
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.
Inlet Turbulence and Length Scale Measurements in a Large Scale Transonic Turbine Cascade
NASA Technical Reports Server (NTRS)
Thurman, Douglas; Flegel, Ashlie; Giel, Paul
2014-01-01
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.
Miracoli, R.; Gammino, S.; Celona, L.; Mascali, D.; Castro, G.; Gobin, R.; Delferriere, O.; Adroit, G.; Senee, F.; Ciavola, G.
2012-05-15
The high intensity ion source (SILHI), in operation at CEA-Saclay, has been used to produce a 90 mA pulsed proton beam with pulse length and repetition rates suitable for the European Spallation Source (ESS) linac. Typical r-r{sup '} rms normalized emittance values smaller than 0.2{pi} mm mrad have been measured for operation in pulsed mode (0.01 < duty cycle < 0.15 and 1 ms < pulse duration < 10 ms) that are relevant for the design update of the Linac to be used at the ESS in Lund.
Asymmetry questionnaire outcomes correlate with several hemisphericity measures.
Morton, Bruce E
2003-04-01
The asymmetry questionnaire segregated subjects (n=143) into two groups. These were significantly correlated with similar groups separated, not only by three new biophysical hemisphericity protocols (Dichotic Deafness Test, Phased Mirror Tracing, Best Hand Test), but also by two preference-type measures (polarity questionnaire, preference questionnaire). Each of the 15 asymmetry questionnaire statements was significantly correlated with the outcomes of these five laterality measures. This is the third questionnaire whose outcomes correlate with those of the new biophysical measures of hemisphericity. PMID:12727192
Multifunctional optical correlator for picosecond ultraviolet laser pulse measurement
Rakhman, Abdurahim; Wang, Yang; Garcia, Frances; Long, Cary D.; Huang, Chunning; Takeda, Yasuhiro; Liu, Yun
2014-01-01
A compact optical correlator system that measures both the autocorrelation between two infrared (IR) lights and the cross-correlation between an IR and an ultraviolet (UV) light using a single nonlinear optical crystal has been designed and experimentally demonstrated. The rapid scanning of optical delay line, switching between auto and cross-correlations, crystal angle tuning, and data acquisition and processing are all computer controlled. Pulse widths of an IR light from a mode-locked laser are measured by the correlator and the results are compared with a direct measurement using a high-speed photodetector system. The correlator has been used to study the parameter dependence of the pulse width of a macropulse UV laser designed for laser-assisted hydrogen ion (H-) beam stripping for the Spallation Neutron Source at Oak Ridge National Laboratory.
Multifunctional optical correlator for picosecond ultraviolet laser pulse measurement
Rakhman, Abdurahim; Wang, Yang; Garcia, Frances; Long, Cary D.; Huang, Chunning; Takeda, Yasuhiro; Liu, Yun
2014-01-01
A compact optical correlator system that measures both the autocorrelation between two infrared (IR) lights and the cross-correlation between an IR and an ultraviolet (UV) light using a single nonlinear optical crystal has been designed and experimentally demonstrated. The rapid scanning of optical delay line, switching between auto and cross-correlations, crystal angle tuning, and data acquisition and processing are all computer controlled. Pulse widths of an IR light from a mode-locked laser are measured by the correlator and the results are compared with a direct measurement using a high-speed photodetector system. The correlator has been used to study the parametermore » dependence of the pulse width of a macropulse UV laser designed for laser-assisted hydrogen ion (H-) beam stripping for the Spallation Neutron Source at Oak Ridge National Laboratory.« less
Multifunctional optical correlator for picosecond ultraviolet laser pulse measurement.
Rakhman, Abdurahim; Wang, Yang; Garcia, Frances; Long, Cary; Huang, Chunning; Takeda, Yasuhiro; Liu, Yun
2014-11-01
A compact multifunctional optical correlator system for pulse width measurement of ultrashort ultraviolet (UV) pulses has been designed and experimentally demonstrated. Both autocorrelation and cross-correlation functions are measured using a single nonlinear crystal, and the switching between two measurements requires no adjustment of phase matching and detector. The system can measure UV pulse widths from sub-picoseconds to 100 ps, and it involves no auxiliary pulse in the measurement. The measurement results on a burst-mode picosecond UV laser show a high-quality performance on speed, accuracy, resolution, and dynamic range. The proposed correlator can be applied to measure any ultrashort UV pulses produced through sum-frequency generation or second-harmonic generation. PMID:25402928
Visual Decisions in the Presence of Measurement and Stimulus Correlations
Bhardwaj, Manisha; Carroll, Samuel; Ma, Wei Ji; Josić, Krešimir
2015-01-01
Humans and other animals base their decisions on noisy sensory input. Much work has been devoted to understanding the computations that underlie such decisions. The problem has been studied in a variety of tasks and with stimuli of differing complexity. However, how the statistical structure of stimuli, along with perceptual measurement noise, affects perceptual judgments is not well understood. Here we examine how correlations between the components of a stimulus—stimulus correlations—together with correlations in sensory noise, affect decision making. As an example, we consider the task of detecting the presence of a single or multiple targets among distractors. We assume that both the distractors and the observer’s measurements of the stimuli are correlated. The computations of an optimal observer in this task are nontrivial yet can be analyzed and understood intuitively. We find that when distractors are strongly correlated, measurement correlations can have a strong impact on performance. When distractor correlations are weak, measurement correlations have little impact unless the number of stimuli is large. Correlations in neural responses to structured stimuli can therefore have a strong impact on perceptual judgments. PMID:26378875
Enhancing robustness of multiparty quantum correlations using weak measurement
Singh, Uttam; Mishra, Utkarsh; Dhar, Himadri Shekhar
2014-11-15
Multipartite quantum correlations are important resources for the development of quantum information and computation protocols. However, the resourcefulness of multipartite quantum correlations in practical settings is limited by its fragility under decoherence due to environmental interactions. Though there exist protocols to protect bipartite entanglement under decoherence, the implementation of such protocols for multipartite quantum correlations has not been sufficiently explored. Here, we study the effect of local amplitude damping channel on the generalized Greenberger–Horne–Zeilinger state, and use a protocol of optimal reversal quantum weak measurement to protect the multipartite quantum correlations. We observe that the weak measurement reversal protocol enhances the robustness of multipartite quantum correlations. Further it increases the critical damping value that corresponds to entanglement sudden death. To emphasize the efficacy of the technique in protection of multipartite quantum correlation, we investigate two proximately related quantum communication tasks, namely, quantum teleportation in a one sender, many receivers setting and multiparty quantum information splitting, through a local amplitude damping channel. We observe an increase in the average fidelity of both the quantum communication tasks under the weak measurement reversal protocol. The method may prove beneficial, for combating external interactions, in other quantum information tasks using multipartite resources. - Highlights: • Extension of weak measurement reversal scheme to protect multiparty quantum correlations. • Protection of multiparty quantum correlation under local amplitude damping noise. • Enhanced fidelity of quantum teleportation in one sender and many receivers setting. • Enhanced fidelity of quantum information splitting protocol.
Estimators for Two Measures of Association for Set Correlation.
ERIC Educational Resources Information Center
Cohen, Jacob; Nee, John C. M.
1984-01-01
Two measures of association between sets of variables have been proposed for set correlation: the proportion of generalized variance, and the proportion of additionive variance. Because these measures are strongly positively biased, approximate expected values and estimators of these measures are derived and checked. (Author/BW)
Apparatus for Measurements of Time and Space Correlation
NASA Technical Reports Server (NTRS)
Favre, Alexandre; Gaviglio, J; Dumas, R
1955-01-01
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.
The ergonomic relevance of anthropometrical proportions. Part I: body length measures.
Küchmeister, Gerd; Behrenbruch, Kay; Ursula, Pieper; Leyk, Dieter
2009-06-01
Anthropometrical findings about proportions of the human body have a long tradition; most of them, however, are rather theoretical. To improve this situation a pragmatic and applicable definition of proportions, normal as well as deviating, is needed. The purpose of this paper is to set up three proportion types for body length measures: leggy-normal-stocky, and their rate in the population of adults in an industrial society (Germany). Based on queries of an actual anthropometrical database metrical limits for these three types are suggested regarding their influence on the most important body length measures in standing and sitting positions. The number of cases with normal proportions is about 60%, leggy and stocky types both reaching up to 20%. The metrical limits are proposed in order to account for differences between those proportion types which are relevant for ergonomics. When solving complex multidimensional design tasks (e.g. workplaces, vehicle interior design, personal equipment) users of anthropometrical data who do not have the opportunity to work with multivariate databases need supplementary information about the proportions of the human body. For this reason such supplementary information concerning proportions is being given here by physiological anthropologists. The application of the findings presented is exemplified in scenarios of ergonomic relevance. PMID:19652449
NASA Astrophysics Data System (ADS)
Chollet, Franck; Ashraf, Mohammed
2009-10-01
The fabrication of microlenses has spurred a lot of interest and resulted in multiple techniques of fabrication in the past decade. However the metrology of these lenses has received less attention and remains a complex and time-consuming task that does not allow frequent control during development and manufacturing. We propose a simple technique based on a standard compound microscope that would allow measuring the focal length of a plano-convex lens and at the same time obtain a measure of the index of refraction of the lens material. The method relies on observing the different images of an object placed in the illumination path of the microscope. Among these images, some are created by the light going through the lens and others by its reflection on the surface. We show that with the image distance and size it is possible to retrieve the focal length and the average index of refraction of the lens material in the case of quasi-spherical lenses. The accuracy obtained by the technique is better than a few per cent and its cost is negligible as it only uses existing equipment.
Do severity measures explain differences in length of hospital stay? The case of hip fracture.
Shwartz, M; Iezzoni, L I; Ash, A S; Mackiernan, Y D
1996-01-01
OBJECTIVE: To examine whether judgments about hospital length of stay (LOS) vary depending on the measure used to adjust for severity differences. DATA SOURCES/STUDY SETTING: Data on admissions to 80 hospitals nationwide in the 1992 MedisGroups Comparative Database. STUDY DESIGN: For each of 14 severity measures, LOS was regressed on patient age/sex, DRG, and severity score. Regressions were performed on trimmed and untrimmed data. R-squared was used to evaluate model performance. For each severity measure for each hospital, we calculated the expected LOS and the z-score, a measure of the deviation of observed from expected LOS. We ranked hospitals by z-scores. DATA EXTRACTION: All patients admitted for initial surgical repair of a hip fracture, defined by DRG, diagnosis, and procedure codes. PRINCIPAL FINDINGS: The 5,664 patients had a mean (s.d.) LOS of 11.9 (8.9) days. Cross-validated R-squared values from the multivariable regressions (trimmed data) ranged from 0.041 (Comorbidity Index) to 0.165 (APR-DRGs). Using untrimmed data, observed average LOS for hospitals ranged from 7.6 to 23.9 days. The 14 severity measures showed excellent agreement in ranking hospitals based on z-scores. No severity measure explained the differences between hospitals with the shortest and longest LOS. CONCLUSIONS: Hospitals differed widely in their mean LOS for hip fracture patients, and severity adjustment did little to explain these differences. PMID:8885854
NASA Technical Reports Server (NTRS)
Leon, R. P.
1987-01-01
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.
NASA Technical Reports Server (NTRS)
Leon, R. P.
1987-01-01
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.
Electro-optical measurements of picosecond bunch length of a 45 MeV electron beam
Tsang, T.; Castillo, V.; Larsen, R.; Lazarus, D. M.; Nikas, D.; Ozben, C.; Semertzidis, Y. K.; Srinivasan-Rao, T.; Kowalski, L.
2001-05-01
We have measured the temporal duration of 45 MeV picosecond electron beam bunches using a noninvasive electro-optical (EO) technique. The amplitude of the EO modulation was found to increase linearly with electron beam charge and decrease inversely with distance from the electron beam. The rise time of the temporal signal was limited by our detection system to {approx}70 ps. The EO signal due to ionization caused by the electrons traversing the EO crystal was also observed. It has a distinctively long decay time constant and signal polarity opposite to that due to the field induced by the electron beam. The electro-optical technique may be ideal for the measurement of bunch length of femtosecond, relativistic, high energy, charged, particle beams.
NASA Technical Reports Server (NTRS)
Norgren, C. T.; Ingebo, R. D.
1976-01-01
Radiometric data were obtained over a range of parametric test conditions at three positions along the length of an experimental combustor segment corresponding to the primary, intermediate, and dilution zones. The concentration of soot entrained in the combustion gases was calculated by a technique using spectral radiance measurements. Tests were conducted primarily with Jet A fuel, although limited data were taken with two fuels having higher aromatic content, diesel oil number 2 and a blend of 40 percent tetralin in Jet A fuel. Radiometric observation of the combustion gases indicated that the maximum total radiance peaked at the intermediate zone, which was located immediately upstream of the dilution holes. Soot concentrations calculated from optical measurements in the dilution zone compared favorably with those obtained by in situ gas sampling at the exhaust. The total radiance increased with the higher aromatic content fuels.
Muralikrishnan, B; Blackburn, C; Sawyer, D; Phillips, S; Bridges, R
2010-01-01
We describe a method to estimate the scale errors in the horizontal angle encoder of a laser tracker in this paper. The method does not require expensive instrumentation such as a rotary stage or even a calibrated artifact. An uncalibrated but stable length is realized between two targets mounted on stands that are at tracker height. The tracker measures the distance between these two targets from different azimuthal positions (say, in intervals of 20° over 360°). Each target is measured in both front face and back face. Low order harmonic scale errors can be estimated from this data and may then be used to correct the encoder's error map to improve the tracker's angle measurement accuracy. We have demonstrated this for the second order harmonic in this paper. It is important to compensate for even order harmonics as their influence cannot be removed by averaging front face and back face measurements whereas odd orders can be removed by averaging. We tested six trackers from three different manufacturers. Two of those trackers are newer models introduced at the time of writing of this paper. For older trackers from two manufacturers, the length errors in a 7.75 m horizontal length placed 7 m away from a tracker were of the order of ± 65 μm before correcting the error map. They reduced to less than ± 25 μm after correcting the error map for second order scale errors. Newer trackers from the same manufacturers did not show this error. An older tracker from a third manufacturer also did not show this error. PMID:27134789
Measurement of the persistence length of polymerized actin using fluorescence microscopy
NASA Astrophysics Data System (ADS)
Ott, A.; Magnasco, M.; Simon, A.; Libchaber, A.
1993-09-01
Single actin filaments were confined between bovine-serum-albumine-coated glass plates, with a separation of about 1 μm, and their flickering Brownian movement was observed by fluorescence microscopy. The rigidity of the filaments was measured by extracting the correlation function given by the mean dot product between unit tangent vectors of an isolated filament. The result is consistent with current rigidity values found in the literature.
Measurement of femtosecond electron pulse length and the temporal broadening due to space charge
NASA Astrophysics Data System (ADS)
Wang, Xuan; Nie, Shouhua; Park, Hyuk; Li, Junjie; Clinite, Rick; Li, Renkai; Wang, Xijie; Cao, Jianming
2009-01-01
The temporal width of ultrashort electron pulses as a function of beam intensity was measured on the femtosecond time scale with a customized streak camera. The results show that the temporal profile of an electron pulse is Gaussian at low beam intensity and progressively evolves to a top-hat shape due to space charge broadening as the beam intensity increases. The strong correlation between the pulse width and beam intensity observed in our streaking measurements agrees very well with the mean-field calculation and supports the main conclusion of previous theoretical studies that the space charge broadening plays a determinant role.
Atmospheric correlation time measurements using coherent CO2 lidar
NASA Technical Reports Server (NTRS)
Ancellet, G. M.; Menzies, R. T.
1986-01-01
A pulsed TEA-CO2 lidar with coherent detection was used to measure the correlation time of backscatter from an ensemble of atmospheric aerosol particles which are illuminated by the pulsed radiation. The correlation time of the backscatter return signal is important in studies of atmospheric turbulence and its effects on optical propagation and backscatter. If the temporal coherence of the pulse is large enough, then the temporal coherence of the return signal is dominated by the turbulence and shear for a variety of interesting atmospheric conditions. Various techniques for correlation time measurement are discussed and evaluated.
Han, Bing; Denlinger, David L
2009-05-01
We report differences in the length of a specific region of the circadian clock gene period (per) that correlate with different capacities for pupal diapause in the flesh fly, Sarcophaga bullata. The conspicuous difference is located in a region we refer to as the putative C-terminal photoperiodic (CP) region. The length of the CP region correlates inversely with the incidence of diapause. A deletion of 33 amino acids in this region correlates with a significant increase in the incidence of diapause, from 78.1% to 93.0%, and an insertion of 9 amino acids in the same area correlates with a drop in the diapause incidence to 4.0%. This correlation suggests a possible functional role for this region of per in photoperiodism. PMID:19186187
Correlations among adiposity measures in school-aged children
2013-01-01
Background Given that it is not feasible to use dual x-ray absorptiometry (DXA) or other reference methods to measure adiposity in all pediatric clinical and research settings, it is important to identify reasonable alternatives. Therefore, we sought to determine the extent to which other adiposity measures were correlated with DXA fat mass in school-aged children. Methods In 1110 children aged 6.5-10.9 years in the pre-birth cohort Project Viva, we calculated Spearman correlation coefficients between DXA (n=875) and other adiposity measures including body mass index (BMI), skinfold thickness, circumferences, and bioimpedance. We also computed correlations between lean body mass measures. Results 50.0% of the children were female and 36.5% were non-white. Mean (SD) BMI was 17.2 (3.1) and total fat mass by DXA was 7.5 (3.9) kg. DXA total fat mass was highly correlated with BMI (rs=0.83), bioimpedance total fat (rs=0.87), and sum of skinfolds (rs=0.90), and DXA trunk fat was highly correlated with waist circumference (rs=0.79). Correlations of BMI with other adiposity indices were high, e.g., with waist circumference (rs=0.86) and sum of subscapular plus triceps skinfolds (rs=0.79). DXA fat-free mass and bioimpedance fat-free mass were highly correlated (rs=0.94). Conclusions In school-aged children, BMI, sum of skinfolds, and other adiposity measures were strongly correlated with DXA fat mass. Although these measurement methods have limitations, BMI and skinfolds are adequate surrogate measures of relative adiposity in children when DXA is not practical. PMID:23799991
Laser-doppler sensor system for speed and length measurements at moving surfaces
NASA Astrophysics Data System (ADS)
Stork, Wilhelm; Wagner, Armin; Kunze, Carsten
2001-10-01
Laser-Doppler Velocimetry is a contact less method for measuring the speed and the path length of moving solid- state surfaces or of fluid streams. In the past the main application of this method was fluid mechanics. No other method was as suitable as Laser-Doppler Anemometry to measure the speed the streams at arbitrary positions. Therefore the market accepted the very high price of these systems. In the past for the measurement of solid-state surfaces mostly other methods with a more reasonable price were used. However from a pure technical point of view a contact less and precise method as Laser-Doppler Velocimetry is also very attractive for the measurement of solid-state surfaces. The method is suitable for nearly any type of technical surface. The measurement procedure does not damage the surfaces and no slippage occurs. These advantages will be become important also for standard applications, if the price of the LDV systems can compete with the price of other methods.
Computable measure of total quantum correlations of multipartite systems
NASA Astrophysics Data System (ADS)
Behdani, Javad; Akhtarshenas, Seyed Javad; Sarbishaei, Mohsen
2016-04-01
Quantum discord as a measure of the quantum correlations cannot be easily computed for most of density operators. In this paper, we present a measure of the total quantum correlations that is operationally simple and can be computed effectively for an arbitrary mixed state of a multipartite system. The measure is based on the coherence vector of the party whose quantumness is investigated as well as the correlation matrix of this part with the remainder of the system. Being able to detect the quantumness of multipartite systems, such as detecting the quantum critical points in spin chains, alongside with the computability characteristic of the measure, makes it a useful indicator to be exploited in the cases which are out of the scope of the other known measures.
Turbulent transport and length scale measurement experiments with comfined coaxial jets
NASA Technical Reports Server (NTRS)
Johnson, B. V.; Roback, R.
1984-01-01
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.
Diffraction effects in coherent transition radiation diagnostics for sub-mm bunch length measurement
Maxwell, T.J.; Mihalcea, D.; Piot, P.; /Northern Illinois U. /Fermilab
2008-09-01
Electrons crossing the boundary between different media generate bursts of transition radiation. In the case of bunches of N electrons, the radiation is coherent and has an N-squared enhancement at wavelengths related to the longitudinal bunch distribution. This coherent transition radiation has therefore attracted attention as an interceptive charged particle beam diagnostic technique. Many analytical descriptions have been devised describing the spectral distribution generated by electron bunches colliding with thin metallic foils making different simplifying assumptions. For typical bunches having lengths in the sub-millimeter range, measurable spectra are generated up into the millimeter range. Analysis of this THz radiation is performed using optical equipment tens of millimeters in size. This gives rise to concern that optical diffraction effects may spread the wavefront of interest into regions larger than the optical elements and partially escape detection, generating a wavelength-dependent instrument response. In this paper we present a model implementing vector diffraction theory to analyze these effects in bunch length diagnostics based on coherent transition radiation.
Zhang, J.; Chowdhury, S.; Messac, A.; Hodge, B. M.
2013-08-01
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.
2011-01-01
Background Surprisingly, in several multi-cellular eukaryotes optimal codon use correlates negatively with gene length. This contrasts with the expectation under selection for translational accuracy. While suggested explanations focus on variation in strength and efficiency of translational selection, it has rarely been noticed that the negative correlation is reported only in organisms whose optimal codons are biased towards codons that end with G or C (-GC). This raises the question whether forces that affect base composition - such as GC-biased gene conversion - contribute to the negative correlation between optimal codon use and gene length. Results Yeast is a good organism to study this as equal numbers of optimal codons end in -GC and -AT and one may hence compare frequencies of optimal GC- with optimal AT-ending codons to disentangle the forces. Results of this study demonstrate in yeast frequencies of GC-ending (optimal AND non-optimal) codons decrease with gene length and increase with recombination. A decrease of GC-ending codons along genes contributes to the negative correlation with gene length. Correlations with recombination and gene expression differentiate between GC-ending and optimal codons, and also substitution patterns support effects of GC-biased gene conversion. Conclusion While the general effect of GC-biased gene conversion is well known, the negative correlation of optimal codon use with gene length has not been considered in this context before. Initiation of gene conversion events in promoter regions and the presence of a gene conversion gradient most likely explain the observed decrease of GC-ending codons with gene length and gene position. PMID:21481245
Axial Length Measurement Failure Rates with the IOLMaster and Lenstar LS 900 in Eyes with Cataract
Pesudovs, Konrad; Yang, Xin; Bao, Fangjun; Yu, Ayong; Lin, Shishi; Feng, Yifan; Huang, Jinhai
2015-01-01
Purpose To evaluate axial length (AL) measurement failure rate with the IOLMaster (Carl Zeiss AG, Germany) and Lenstar LS 900 (Haag-Streit AG, Switzerland) in eyes with cataract. Methods Two hundred and ninety-six eyes of 170 patients with cataract were enrolled. Cataract type and severity were graded using the Lens Opacities Classification System III (LOCS III) and AL measurements were attempted with IOLMaster (version 5.4) and Lenstar LS 900 (version 1.1). Chi-squared analysis was used to assess if the difference in AL measurement acquisition rate was statistically significant between the two devices. The association of the different cataract types and severity with the AL measurement acquisition rate was evaluated with logistic regression analysis. Results AL measurements were obtained in 184 eyes (62.16%) using the IOLMaster and 191 eyes (64.53%) using the Lenstar, which corresponds to a failure rate of 37.84% and 35.47% respectively. Chi-square analysis indicated no significant difference between the Lenstar and IOLMaster for AL measurement failure rate (x2 = 0.356, P = 0.550). Logistic regression analysis indicated no association between acquisition rates and cortical or nuclear cataracts with either device. There was a statistically significant association between acquisition rates and increasing severity of posterior subcapsular cataracts with the IOLMaster (β = -1.491, P<0.001) and Lenstar LS 900 (β = -1.507, P<0.001). Conclusion The IOLMaster and Lenstar LS 900 have similar AL measurement failure rates (35–38%) for Chinese public hospital cataract patients. Increasing severity of posterior subcapsular cataracts was problematic for both devices. PMID:26061554
ERIC Educational Resources Information Center
Deutsch, Donald R.; Kraft, Donald H.
A framework is developed to evaluate expected search length, an important measure of an information storage and retrieval system's performance, as a function of the size of the information file and its organization in terms of indexing search structure. Previous research pertaining to search length by W.S. Cooper and others is surveyed and…
The Measurement and Correlates of Career Decision Making.
ERIC Educational Resources Information Center
Harren, Vincent A.; Kass, Richard A.
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…
Internalized Heterosexism: Measurement, Psychosocial Correlates, and Research Directions
ERIC Educational Resources Information Center
Szymanski, Dawn M.; Kashubeck-West, Susan; Meyer, Jill
2008-01-01
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…
Statistical measures of Planck scale signal correlations in interferometers
Hogan, Craig J.; Kwon, Ohkyung
2015-06-22
A model-independent statistical framework is presented to interpret data from systems where the mean time derivative of positional cross correlation between world lines, a measure of spreading in a quantum geometrical wave function, is measured with a precision smaller than the Planck time. The framework provides a general way to constrain possible departures from perfect independence of classical world lines, associated with Planck scale bounds on positional information. A parametrized candidate set of possible correlation functions is shown to be consistent with the known causal structure of the classical geometry measured by an apparatus, and the holographic scaling of information suggested by gravity. Frequency-domain power spectra are derived that can be compared with interferometer data. As a result, simple projections of sensitivity for specific experimental set-ups suggests that measurements will directly yield constraints on a universal time derivative of the correlation function, and thereby confirm or rule out a class of Planck scale departures from classical geometry.
Measuring telomere length and telomere dynamics in evolutionary biology and ecology
Nussey, Daniel H; Baird, Duncan; Barrett, Emma; Boner, Winnie; Fairlie, Jennifer; Gemmell, Neil; Hartmann, Nils; Horn, Thorsten; Haussmann, Mark; Olsson, Mats; Turbill, Chris; Verhulst, Simon; Zahn, Sandrine; Monaghan, Pat
2014-01-01
Telomeres play a fundamental role in the protection of chromosomal DNA and in the regulation of cellular senescence. Recent work in human epidemiology and evolutionary ecology suggests adult telomere length (TL) may reflect past physiological stress and predict subsequent morbidity and mortality, independent of chronological age. Several different methods have been developed to measure TL, each offering its own technical challenges. The aim of this review is to provide an overview of the advantages and drawbacks of each method for researchers, with a particular focus on issues that are likely to face ecologists and evolutionary biologists collecting samples in the field or in organisms that may never have been studied in this context before. We discuss the key issues to consider and wherever possible try to provide current consensus view regarding best practice with regard to sample collection and storage, DNA extraction and storage, and the five main methods currently available to measure TL. Decisions regarding which tissues to sample, how to store them, how to extract DNA, and which TL measurement method to use cannot be prescribed, and are dependent on the biological question addressed and the constraints imposed by the study system. What is essential for future studies of telomere dynamics in evolution and ecology is that researchers publish full details of their methods and the quality control thresholds they employ. PMID:25834722
Optical correlation technique for cement particle size measurements
NASA Astrophysics Data System (ADS)
Gorsky, M. P.; Maksimyak, P. P.
2015-11-01
Article describes optical correlation method of cement particle size distribution definition. It based on transverse coherent function definition. It has been shown that set of particles with random shapes and orientations produces correlation function which is almost the same as a function for round particles set. Measurements of coherence function are performed using polarization transverse shearing interferometer. Described method allows fast and high reliable definition of cement particle distribution by sizes.
Analyzing complex networks through correlations in centrality measurements
NASA Astrophysics Data System (ADS)
Furlan Ronqui, José Ricardo; Travieso, Gonzalo
2015-05-01
Many real world systems can be expressed as complex networks of interconnected nodes. It is frequently important to be able to quantify the relative importance of the various nodes in the network, a task accomplished by defining some centrality measures, with different centrality definitions stressing different aspects of the network. It is interesting to know to what extent these different centrality definitions are related for different networks. In this work, we study the correlation between pairs of a set of centrality measures for different real world networks and two network models. We show that the centralities are in general correlated, but with stronger correlations for network models than for real networks. We also show that the strength of the correlation of each pair of centralities varies from network to network. Taking this fact into account, we propose the use of a centrality correlation profile, consisting of the values of the correlation coefficients between all pairs of centralities of interest, as a way to characterize networks. Using the yeast protein interaction network as an example we show also that the centrality correlation profile can be used to assess the adequacy of a network model as a representation of a given real network.
Direct measurement of correlation functions in a lattice Lorentz gas
NASA Technical Reports Server (NTRS)
Binder, P.-M.; Frenkel, D.
1990-01-01
Simulations of a two-dimensional ballistic Lorentz gas on a lattice are reported. A moment-propagation technique allows direct measurements of the velocity correlation function and its moments with low relative errors for all times. The predicted 1/t-sq algebraic tails in the velocity correlation function are observed at all studied scatterer densities, unlike what has been reported for continuous systems. In the square lattice a fast oscillation is observed, consistent with the existence of staggered density modes. For the second-rank tensor correlation function, an extremely slow approach to the expected 1/t exp 3 tail is found.
First Measurements of Pion Correlations by the PHENIX Experiment
Johnson, S C
2001-04-11
First identical-pion correlations measured at RHIC energies by PHENIX are presented. Two analyses with separate detectors, systematics, and statistics provide consistent results. The resulting HBT radii are moderately larger than those measured at lower energies. The k{sub t} dependence of the Bertsch-Pratt HBT radii is also similar to previous measures and is consistent with the conjecture of an expanding source.
Accuracy of axial length measurements from immersion B-scan ultrasonography in highly myopic eyes
Yang, Qing-Hua; Chen, Bing; Peng, Guang-Hua; Li, Zhao-Hui; Huang, Yi-Fei
2014-01-01
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
Fan, Xinyu; Koshikiya, Yusuke; Ito, Fumihiko
2007-11-15
A novel type of optical frequency domain reflectometry with a measurement range much longer than the laser coherence length is proposed and experimentally demonstrated. To reduce the influence of laser phase noise, the measurement signal is compensated by using reference signals generated from a single auxiliary interferometer supported by a newly proposed compensation process. The compensation is accomplished numerically with a computer for each section of the delay fiber length in an auxiliary interferometer after only one data acquisition. By using the proposed technique, it is confirmed experimentally that the laser phase noise is well compensated even beyond the coherence length. PMID:18026262
Avian hind-limb digit length ratios measured from radiographs are sexually dimorphic
Leoni, Barbara; Rubolini, Diego; Romano, Maria; di Giancamillo, Mauro; Saino, Nicola
2008-01-01
Sexual dimorphism in digit length ratios is well established in humans, and has been reported in other vertebrate species as well, including birds. The sign of sexual dimorphism in digit ratios may, however, vary both within and between vertebrate classes. It has been hypothesized that sex differences in digit ratios arise via differential prenatal exposure of the two sexes to steroids, which may affect the expression of the Hox genes controlling the osteometric development of digits and appendices. Among birds, the evidence for sex dimorphism in hind-limb digit ratios is conflicting, though all previous studies were based on measurements of undissected digits, implying that results could be confounded by sex-related variation in soft tissues. Here we report that digit ratios derived from radiographs of both feet of a large passerine bird, the hooded crow (Corvus corone), are sexually dimorphic, males showing larger 2D : 3D (effect size, r = 0.33) and 2D : 4D than females (effect size, r = 0.28). We also observed a good agreement (r = 0.45) between radiographic estimates of digit ratios and digit ratios calculated based on undissected digit measurements (thus including soft tissues). Importantly, we found that the patterns of sex and side differences were largely coherent between the two methods. Therefore, our findings show for the first time in avian species that sex differences in digit ratios have an osteometric basis, a fundamental prerequisite for a role of Hox genes in originating such dimorphism. PMID:18691377
NASA Astrophysics Data System (ADS)
Bulzacchelli, John F.; Lee, Hae-Seung; Hong, Merit Y.; Misewich, James A.; Ketchen, Mark B.
2003-12-01
Segmented correlation is a useful technique for testing a superconducting analogue-to-digital converter, as it allows the output spectrum to be estimated with fine frequency resolution even when data record lengths are limited by small on-chip acquisition memories. Previously, we presented segmented correlation measurements on a superconducting bandpass delta-sigma modulator sampling at 40.2 GHz under idle channel (no input) conditions. This paper compares the modulator output spectra measured by segmented correlation with and without an input tone. Important practical considerations of calculating segmented correlations are discussed in detail. Resolution enhancement by segmented correlation does reduce the spectral width of the input tone in the desired manner, but the signal power due to the input increases the variance of the spectral estimate near the input frequency, hindering accurate calculation of the in-band noise. This increased variance, which is predicted by theory, must be considered carefully in the application of segmented correlation. Methods for obtaining more accurate estimates of the quantization noise spectrum which are closer to those measured with no input are described.
Measuring short electron bunch lengths using coherent Smith-Purcell radiation
Nguyen, D.C.
1999-03-30
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.
Measuring short electron bunch lengths using coherent smith-purcell radiation
Nguyen, Dinh C.
1999-01-01
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.
Knafo, A; Israel, S; Darvasi, A; Bachner-Melman, R; Uzefovsky, F; Cohen, L; Feldman, E; Lerer, E; Laiba, E; Raz, Y; Nemanov, L; Gritsenko, I; Dina, C; Agam, G; Dean, B; Bornstein, G; Ebstein, R P
2008-04-01
Human altruism is a widespread phenomenon that puzzled evolutionary biologists since Darwin. Economic games illustrate human altruism by showing that behavior deviates from economic predictions of profit maximization. A game that most plainly shows this altruistic tendency is the Dictator Game. We hypothesized that human altruistic behavior is to some extent hardwired and that a likely candidate that may contribute to individual differences in altruistic behavior is the arginine vasopressin 1a (AVPR1a) receptor that in some mammals such as the vole has a profound impact on affiliative behaviors. In the current investigation, 203 male and female university students played an online version of the Dictator Game, for real money payoffs. All subjects and their parents were genotyped for AVPR1a RS1 and RS3 promoter-region repeat polymorphisms. Parents did not participate in online game playing. As variation in the length of a repetitive element in the vole AVPR1a promoter region is associated with differences in social behavior, we examined the relationship between RS1 and RS3 repeat length (base pairs) and allocation sums. Participants with short versions (308-325 bp) of the AVPR1a RS3 repeat allocated significantly (likelihood ratio = 14.75, P = 0.001, df = 2) fewer shekels to the 'other' than participants with long versions (327-343 bp). We also implemented a family-based association test, UNPHASED, to confirm and validate the correlation between the AVPR1a RS3 repeat and monetary allocations in the dictator game. Dictator game allocations were significantly associated with the RS3 repeat (global P value: likelihood ratio chi(2) = 11.73, df = 4, P = 0.019). The association between the AVPR1a RS3 repeat and altruism was also confirmed using two self-report scales (the Bardi-Schwartz Universalism and Benevolence Value-expressive Behavior scales). RS3 long alleles were associated with higher scores on both measures. Finally, long AVPR1a RS3 repeats were associated with higher AVPR1a human post-mortem hippocampal messenger RNA levels than short RS3 repeats (one-way analysis of variance (ANOVA): F = 15.04, P = 0.001, df = 14) suggesting a functional molecular genetic basis for the observation that participants with the long RS3 repeats allocate more money than participants with the short repeats. This is the first investigation showing that a common human polymorphism, with antecedents in lower mammals, contributes to decision making in an economic game. The finding that the same gene contributing to social bonding in lower animals also appears to operate similarly in human behavior suggests a common evolutionary mechanism. PMID:17696996
Acoustic ship signature measurements by cross-correlation method.
Fillinger, Laurent; Sutin, Alexander; Sedunov, Alexander
2011-02-01
Cross-correlation methods were applied for the estimation of the power spectral density and modulation spectrum of underwater noise generated by moving vessels. The cross-correlation of the signal from two hydrophones allows the separation of vessel acoustic signatures in a busy estuary. Experimental data recorded in the Hudson River are used for demonstration that cross-correlation method measured the same ship noise and ship noise modulation spectra as conventional methods. The cross-correlation method was then applied for the separation of the acoustic signatures of two ships present simultaneously. Presented methods can be useful for ship traffic monitoring and small ship classification, even in noisy harbor environments. PMID:21361436
Negative correlation and optimal tracking with Doppler measurements
NASA Astrophysics Data System (ADS)
Bar-Shalom, Yaakov
2000-07-01
In target tracking systems that utilize Doppler radar (or sonar), the measurements consist of range, range rate and one or two angles. When multiple sensors are used in the proper geometry, the final accuracy is determined primarily by each sensor's range estimation accuracy. In this case it is particularly important to extract the most accurate state estimate in the range direction by processing optimally the range and range rate measurements. The usual assumption in the design of tracking filters is that the measurement errors in range and range rate are uncorrelated. However, in the case of the commonly used upsweep chirp (linear FM) waveforms, there is a significant negative correlation between the range and range rate measurement noises. The purpose of this note is to quantify the performance improvement one can obtain when this correlation is present and accounted for.
Mullany, LC; Darmstadt, GL; Khatry, SK; LeClerq, SC; Tielsch, JM
2008-01-01
Background Classification of infants into low birth weight (LBW, <2500 g) or very low birth weight (VLBW, <2000 g) categories is a crucial step in targeting interventions to high-risk infants. Objective To compare the validity of chest circumference and foot length as surrogate anthropometric measures for the identification of LBW and VLBW infants. Subjects and setting Newborn infants (n = 1640) born between March and June 2004 in 30 Village Development Committees of Sarlahi district, Nepal. Design Chest circumference, foot length and weight (SECA 727, precise to 2 g) of newborns were measured within 72 h after birth. The sensitivity, specificity and predictive values for a range of cutoff points of the anthropometric measures were estimated using the digital scale measurements as the gold standard. Results Among LBW infants (469/1640, 28.6%), chest circumference measures <30.3 cm were 91% sensitive and 83% specific. Similar levels of sensitivity for foot length were achieved only with considerable loss of specificity (<45%). Foot length measurements <6.9 cm were 88% sensitive and 86% specific for the identification of VLBW infants. Conclusion Chest circumference was superior to foot length in classification of infants into birth weight categories. For the identification of VLBW infants, foot length performed well, and may be preferable to chest circumference, as the former measure does not require removal of infant swaddling clothes. In the absence of more precise direct measures of birth weight, chest circumference is recommended over foot length for the identification of LBW infants. Sponsorship The National Institute of Child Health and Human Development; the Saving Newborn Lives Initiative, Save the Children US and the Office of Heath and Nutrition, United States Agency for International Development (see Acknowledgements). PMID:16885929
Direct measurements of hydrophobic slippage using double-focus fluorescence cross-correlation.
Vinogradova, Olga I; Koynov, Kaloian; Best, Andreas; Feuillebois, François
2009-03-20
We report the results of direct measurements of velocity profiles in a microchannel with hydrophobic and hydrophilic walls, using a new high-precision method of double-focus spatial fluorescence cross correlation under a confocal microscope. In the vicinity of both walls the measured velocity profiles do not go to zero by supplying a plateau of constant velocity. This apparent slip is proven to be due to a Taylor dispersion, an augmentation by shear diffusion of nanotracers in the direction of flow. Comparing the velocity profiles near the hydrophobic and hydrophilic walls for various conditions shows that there is a true slip length due to hydrophobicity. This length, of the order of several tens of nanometers, is independent of the electrolyte concentration and shear rate. PMID:19392250
Direct Measurements of Hydrophobic Slippage Using Double-Focus Fluorescence Cross-Correlation
NASA Astrophysics Data System (ADS)
Vinogradova, Olga I.; Koynov, Kaloian; Best, Andreas; Feuillebois, François
2009-03-01
We report the results of direct measurements of velocity profiles in a microchannel with hydrophobic and hydrophilic walls, using a new high-precision method of double-focus spatial fluorescence cross correlation under a confocal microscope. In the vicinity of both walls the measured velocity profiles do not go to zero by supplying a plateau of constant velocity. This apparent slip is proven to be due to a Taylor dispersion, an augmentation by shear diffusion of nanotracers in the direction of flow. Comparing the velocity profiles near the hydrophobic and hydrophilic walls for various conditions shows that there is a true slip length due to hydrophobicity. This length, of the order of several tens of nanometers, is independent of the electrolyte concentration and shear rate.
CORRELATION OF EGG PHYSICAL QUALITY MEASUREMENTS AND FUNCTIONAL DETERMINATIONS
Technology Transfer Automated Retrieval System (TEKTRAN)
Both physical and functional determinations have served as a means for determining shell egg quality. A study was conducted to determine if correlations exist between these types of egg quality measurements. Shell eggs were collected weekly after processing from a U.S. inline processing facility f...
Correlation between hyperacusis measurements in daily ENT practice.
Meeus, Olivier M; Spaepen, Mattias; Ridder, Dirk De; Heyning, Paul H Van de
2010-01-01
The aim of this study was to investigate hyperacusis measurement tools and to assess the correlation between diagnostic methods for hyperacusis in daily ENT practice. We studied two hyperacusis questionnaires: the Hyperacusis Questionnaire (HQ) and the Multiple-Activity Scale for Hyperacusis (MASH), audiometric measurements (uncomfortable loudness level (ULL) and dynamic range (DR)), and the questions 'Do you have a lower tolerance for noise... ?' and 'Are you afraid of noise?' Hyperacusis was assessed in 46 patients presenting with primary complaints of tinnitus. A validated Dutch version of the HQ is provided. A correlation was found between scores on the HQ and the MASH (p=0.000, R(2)=0.34). Significantly higher scores for both questionnaires were found in patients reporting decreased sound tolerance (p=0.000 and 0.002, respectively) or fear of noise (p=0.002 and 0.004, respectively). Overall, no correlations were found between scores on questionnaires and audiometric values including ULL and DR. The HQ and MASH were confirmed to be valid measurement tools for hyperacusis complaints. No correlations were found between audiometric measurements and hyperacusis complaints. PMID:20053152
PROTOTYPE CORRELATION MASK FLAME PHOTOMETRIC DETECTOR FOR MEASURING SULFUR DIOXIDE
A prototype flame photometric detector system (FPD) to measure gaseous sulfur compounds was fabricated using a previously developed correlation mask optical system and a new flame housing. Also, a new burner for the FPD system was optimized to view the excited molecular sulfur em...
Constrained tension control of a tethered space-tug system with only length measurement
NASA Astrophysics Data System (ADS)
Wen, Hao; Zhu, Zheng H.; Jin, Dongping; Hu, Haiyan
2016-02-01
The paper presents a tension control law to stabilize the motions of a Tethered Space-Tug system during its deorbiting process by regulating the tension in the tether. The tension control law is designed on a basis of two straightforward ideas, i.e., the potential energy shaping and the damping injection. The law is expressed in an analytical feedback form in terms of only the tether length without the need of the feedback of full state information. Meanwhile, the requirements of measuring velocities are removed with the aid of a dynamic extension technique based on the feedback interconnection of Euler-Lagrange systems. The positive and bounded tension constraint is taken into consideration explicitly by including a pair of special saturation terms in the feedback control law. The relative motions of the space-tug and the debris are described with respect to a local non-inertial orbital frame of reference, whereas the orbital motion equations of the system are formulated in terms of the modified equinoctial elements of the orbit. Finally, the effectiveness of the proposed scheme is demonstrated via numerical case studies.
Franchignoni, F; Tesio, L; Martino, M T; Benevolo, E; Castagna, M
1998-01-01
A model for prediction of length of stay (LOS, in days) of stroke rehabilitation inpatients was developed, based on patients' age (years) and function at admission (scored on the Functional Independence Measure, FIMSM). One hundred and twenty-nine cases, consecutively admitted to three free-standing rehabilitation centres in Italy, were analyzed. A multiple linear regression using forward stepwise selection procedure was adopted. Median admission and discharge scores were: 57 and 75 for the total FIM score, 29 and 48 for the 13-item motor FIM subscore, 29 and 30 for the 5-item cognitive FIM subscore (potential range: 18-126, 13-91, 5-35, respectively). Median LOS was 44 days (interquartile range 30-62). The logLOS predictive model included three FIM items ("toilet transfer", TTr; "social interaction"; "expression") and patient's age (R2 = 0.48). TTr alone explained 31.3% of the variance of logLOS. These results are consistent with previous American studies, showing that FIM scores at admission are strong predictors of patients' LOS, with the transfer items having the greatest predictive power. PMID:10234877
Degree of polarization as a cross-correlation detector for absolute distance measurement
NASA Astrophysics Data System (ADS)
Castro Alves, D.; Abreu, Manuel; Cabral, Alexandre; Rebordão, J. M.
2013-11-01
We present an absolute distance measurement concept based on pulse frequency repetition (PRF) sweep with a mode-locked laser diode. This technique requires a Michelson interferometer, a mode-locked laser source and a cross-correlation detector. The role of the cross-correlator is to analyze the state of superposition of a pair of pulses, one travelling over the reference arm of the interferometer, the other, corresponding to the measuring arm, travelling from the apparatus to the target and reflected back. Using two distinct laser pulse repetition frequency and knowing the cross-correlation peak position at reference arm of the interferometer for each frequency, it's possible to obtain the length of the measuring arm, i.e., a distance measuring. The main techniques for performing pulse correlation are based in 2nd order effects over second harmonic crystal (SHG) or a two-photon absorption (TPA) process in a semiconductor junction. Both SHG and TPA methods require reasonably high pulse energies to achieve fair signal to noise ratios. The use Degree of Polarization (DOP) technique for cross-correlation detection allows the use of optical powers as low as -60 dBm. Such high sensitivity can be very convenient for low energy pulse sources such is the case of high frequency mode-locked laser diodes. The DOP technique can however limit the maximum measurement range, constrained by the loss of coherence of the laser source for longer distances. In this paper we present the first results of this measurement concept, based in the DOP correlator, discussing the main limitations of this technique for long distance measurements.
Two Point Space-Time Correlation of Density Fluctuations Measured in High Velocity Free Jets
NASA Technical Reports Server (NTRS)
Panda, Jayanta
2006-01-01
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.
Kok, A; van Middelaar, C E; Engel, B; van Knegsel, A T M; Hogeveen, H; Kemp, B; de Boer, I J M
2016-04-01
To compare milk yields between cows or management strategies, lactations are traditionally standardized to 305-d yields. The 305-d yield, however, gives no insight into the combined effect of additional milk yield before calving, decreased milk yield after calving, and a possible shorter calving interval in the case of a shortened dry period. We aimed to develop a measure that would enable the comparison of milk yield between cows with different dry period (DP) lengths. We assessed the importance of accounting for additional milk yield before calving and for differences in calving interval. The 305-d yield was compared with a 365-d yield, which included additional milk yield in the 60d before calving. Next, an effective lactation yield was computed, defined as the daily yield from 60d before calving to 60d before the next calving, to account for additional milk yield before calving and for differences in calving interval. Test-day records and drying-off dates of 15 commercial farms were used to compute the 305-d, 365-d, and effective lactation yields for individual cows. We analyzed 817 second-parity lactations preceded by no DP, a short DP (20 to 40d), or a conventional DP (49 to 90d). Compared with cows with a conventional DP, the 305-d yield of cows with no DP was 7.0kg of fat- and protein-corrected milk (FPCM) per day lower, and the 305-d yield of cows with a short DP was 2.3kg of FPCM per day lower. Including additional milk yield before calving in the 365-d yield reduced this difference to 3.4kg of FPCM per cow per day for cows with no DP and to 0.9kg of FPCM per cow per day for cows with a short DP. Compared with cows with a conventional DP, median days open were reduced by 25d for cows with no DP and by 18d for cows with a short DP. Accounting for these differences in calving interval in the effective lactation yield further decreased yield reductions for cows with no DP or a short DP by 0.3kg of FPCM per cow per day. At the herd level, estimated 365-d yield losses for cows with no DP or a short DP differed from effective lactation yield losses by 0.4 to -0.8kg FPCM per cow per day. Accounting for additional milk yield before calving had a major and consistent effect on yield comparisons of cows with different DP lengths. The effect of correcting for calving interval was more variable between farms and will especially be important when calving interval is affected by DP length. PMID:26851847
Measurement-induced disturbances and nonclassical correlations of Gaussian states
Mista, Ladislav Jr.; Tatham, Richard; Korolkova, Natalia; Girolami, Davide; Adesso, Gerardo
2011-04-15
We study quantum correlations beyond entanglement in two-mode Gaussian states of continuous-variable systems by means of the measurement-induced disturbance (MID) and its ameliorated version (AMID). In analogy with the recent studies of the Gaussian quantum discord, we define a Gaussian AMID by constraining the optimization to all bi-local Gaussian positive operator valued measurements. We solve the optimization explicitly for relevant families of states, including squeezed thermal states. Remarkably, we find that there is a finite subset of two-mode Gaussian states comprising pure states where non-Gaussian measurements such as photon counting are globally optimal for the AMID and realize a strictly smaller state disturbance compared to the best Gaussian measurements. However, for the majority of two-mode Gaussian states the unoptimized MID provides a loose overestimation of the actual content of quantum correlations, as evidenced by its comparison with Gaussian discord. This feature displays strong similarity with the case of two qubits. Upper and lower bounds for the Gaussian AMID at fixed Gaussian discord are identified. We further present a comparison between Gaussian AMID and Gaussian entanglement of formation, and classify families of two-mode states in terms of their Gaussian AMID, Gaussian discord, and Gaussian entanglement of formation. Our findings provide a further confirmation of the genuinely quantum nature of general Gaussian states, yet they reveal that non-Gaussian measurements can play a crucial role for the optimized extraction and potential exploitation of classical and nonclassical correlations in Gaussian states.
Weighted fuzzy correlation for similarity measure of color-histograms
NASA Astrophysics Data System (ADS)
Zhai, Hongchen; Chavel, Pierre; Wang, Yi; Zhang, Siyuan; Liang, Yanmei
2005-03-01
In this report, fuzzy correlation of color-histograms is proposed for the similarity measure between the color contents of images. By employing a weighted algorithm on the process of calculating the peak value of the correlation, it offers the flexibility to adapt to an image and its best matching images with partial color distortion or local color characters. Experimental examples demonstrate the effectiveness of the proposed method in its application to the retrieval of color images of interest specified by their color content.
Park, So Yeong; Hong, Chung Ki; Lim, Jun
2014-04-01
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 μm (horizontal) × 50 μm (vertical). PMID:24784668
Park, So Yeong; Hong, Chung Ki; Lim, Jun
2014-04-15
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 μm (horizontal) × 50 μm (vertical)
NASA Astrophysics Data System (ADS)
Park, So Yeong; Hong, Chung Ki; Lim, Jun
2014-04-01
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 μm (horizontal) × 50 μm (vertical).
Hisagi, Miwako; Shafer, Valerie L; Strange, Winifred; Sussman, Elyse S
2015-11-11
This study examined automaticity of discrimination of a Japanese length contrast for consonants (miʃi vs. miʃʃi) in native (Japanese) and non-native (American-English) listeners using behavioral measures and the event-related potential (ERP) mismatch negativity (MMN). Attention to the auditory input was manipulated either away from the auditory input via a visual oddball task (Visual Attend), or to the input by asking the listeners to count auditory deviants (Auditory Attend). Results showed a larger MMN when attention was focused on the consonant contrast than away from it for both groups. The MMN was larger for consonant duration increments than decrements. No difference in MMN between the language groups was observed, but the Japanese listeners did show better behavioral discrimination than the American English listeners. In addition, behavioral responses showed a weak, but significant correlation with MMN amplitude. These findings suggest that both acoustic-phonetic properties and phonological experience affects automaticity of speech processing. This article is part of a Special Issue entitled SI: Prediction and Attention. PMID:26119918
Correlation techniques and measurements of wave-height statistics
NASA Technical Reports Server (NTRS)
Guthart, H.; Taylor, W. C.; Graf, K. A.; Douglas, D. G.
1972-01-01
Statistical measurements of wave height fluctuations have been made in a wind wave tank. The power spectral density function of temporal wave height fluctuations evidenced second-harmonic components and an f to the minus 5th power law decay beyond the second harmonic. The observations of second harmonic effects agreed very well with a theoretical prediction. From the wave statistics, surface drift currents were inferred and compared to experimental measurements with satisfactory agreement. Measurements were made of the two dimensional correlation coefficient at 15 deg increments in angle with respect to the wind vector. An estimate of the two-dimensional spatial power spectral density function was also made.
ERIC Educational Resources Information Center
Steinbrink, Claudia; Groth, Katarina; Lachmann, Thomas; Riecker, Axel
2012-01-01
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…
Sharma, M.K.; Bringham, W.E.; Shah, D.O.
1984-05-01
The effects of chain length compatibility and surface properties of mixed foaming agents on fluid displacement efficiency and effective air mobility in porous media were investigated. Sodium dodecyl sulfate (C/sub 12/H/sub 25/SO/sub 4/Na) and various alkyl alcohols (e.g., C/sub 8/OH,C/sub 10/OH,C/sub 12/OH,C/sub 14/OH, and C/sub 16/OH) were used as mixed foaming agents. It was observed that the surface properties of surfactant solutions and flow behavior of foams through porous media were influenced by the chain length compatibility of the surfactant molecules. The increase in the length of porous media improved fluid displacement efficiency while breakthrough time per unit length decreased slightly with increase in the length of porous media. For mixed surfactant systems, a minimum in surface tension, a maximum in surface viscosity, a minimum in bubble size, a maximum in breakthrough time, a maximum in fluid displacement efficiency, and a minimum in effective air mobility were observed when the two components of the surfactant system had the same chain length. These results indicate that the surface properties of foaming solutions and molecular packing at interfaces exhibit a striking correlation with breakthrough time, fluid displacement efficiency, and effective air mobility in porous media.
Postle, B R; Berger, J S; Goldstein, J H; Curtis, C E; D'Esposito, M
2001-03-01
Updating refers to (1) discarding items from, (2) repositioning items in, and (3) adding items to a running working memory span. Our behavioral and fMRI experiments varied three factors: trial length, proactive interference (PI), and group integrity. Group integrity reflected whether the grouping of items at the encoding stage was violated at discarding. Behavioral results were consistent with the idea that updating processes have a relatively short refractory period and may not fatigue, and they revealed that episodic information about group context is encoded automatically in working memory stimulus representations. The fMRI results did not show evidence that updating requirements in a task recruit executive control processes other than those supporting performance on nonupdating trials. They did reveal an item-accumulation effect, in which signal increased monotonically with the number of items presented during the trial, despite the insensitivity of behavioral measures to this factor. Behavioral and fMRI correlates of PI extended previous results and rejected an alternative explanation of PI effects in working memory. PMID:12467100
Technology Transfer Automated Retrieval System (TEKTRAN)
Genetic parameters for length of productive life given the opportunity (LPL|O), measured as days between first calving and disposal conditioned on one of six opportunity groups, (e.g., L2 is length of productive life in days given the opportunity to live 2 yr after first calving), and lifetime produ...
Chappard, D; Degasne, I; Huré, G; Legrand, E; Audran, M; Baslé, M F
2003-04-01
Surface properties of a biomaterial are important factors that govern in part its biocompatibility. Among them, surface roughness is now recognized as a very important factor for cell interactions. Surface roughness (Ra) is routinely measured by contact profilometry but other methods are presently usable. We compared two methods (contact profilometry and image analysis of scanning electron microscopic images SEM) on a series of 12 titanium test pieces. The texture analysis of SEM pictures was done by the heterogeneity and run-length methods. Fractal geometry was also used with the "skyscraper" and "blanket" methods providing respectively the D(SKY) and D(BLANK) fractal dimensions. The fractal dimension of the profilometric curve was also computed (D(MINK)). Computer-simulated textures were used to evaluate the pertinence of the algorithms. A significant correlation was found between Ra and all the texture descriptors except heterogeneity. The correlation coefficient was dependent on the microscopic magnification. The fractal dimension of the curve was correlated with D(SKY) and D(BLANK). Run-length, D(SKY) and D(BLANK) were highly correlated, independent of the magnification used, a finding related to the self-similarity of the images. Image texture analysis can be a useful alternative to profilometry with brittle or soft materials or with objects having a complex shape. PMID:12527281
Shot noise measurement in a strongly correlated material
NASA Astrophysics Data System (ADS)
Zhou, Panpan; Hardy, Will; Cho, Ethan; Cybart, Shane; Dynes, Robert; Natelson, Douglas
In strongly correlated materials, the motion of an electron is strongly affected by interactions with other electrons, leading to many interesting phenomena including metal-insulator transitions, colossal magnetoresistance, and high temperature superconductivity. Shot noise is one experimental probe for electronic correlations beyond simple electronic transport. Shot noise, which originates from the discrete nature of the charge-carrying particles, can be strongly affected by electronic correlations. Here we report initial shot noise measurements in tunnel junctions prepared from a YBa2Cu3O7-x film sample, with nanoscale junctions written by focused helium ion beam. We will discuss a comparison of the shot noise between the YBCO film sample and standard tunnel junctions, as a function of temperature and bias, and the implications of these results.
Correlation Between NDE Measurements and Elongation of Aluminum
Thompson, R. Bruce; Margetan, Frank J.; Nakagawa, Norio; Haldipur, Pranaam
2007-03-21
Complex aluminum forgings can have engineering properties which vary with position due to changes in the underlying local metal microstructure. Consequently, the material properties may be in compliance with production requirements in some regions of the forging, but out of compliance in others. One conical Al-7050 forging of interest was found to have elongation properties which failed required tests in certain regions. NDE measurements sensitive to microstructural changes were carried out to search for correlations with elongation properties. The results of a set of initial feasibility experiments will be reported. Both ultrasonic and eddy current NDE methods were used, with the goal being to determine which properties were sensitive to the elongation. Ultrasonic testing included the measurement of longitudinal and shear-wave velocity, longitudinal wave attenuation, and longitudinal and shear-wave backscattered grain noise. All tests were performed with the sonic beam entering through the coupon face that would be adjacent to the outer surface of the forging. Only modest differences in wave speed and attenuation values were seen among the suite of coupons, but significant differences were seen in backscattered noise levels. These appeared to indicate changes in grain structure but only exhibited partial correlation with elongation. The eddy current measurements were designed to be sensitive to the electrical resistivity. Included were a number of measurement configurations and frequencies. The signals exhibited a significant correlation with elongation.
NASA Astrophysics Data System (ADS)
Montanini, R.; Freni, F.
2014-01-01
A new non-contact optical method (IIC, infrared image correlation) for the determination of the coefficients of thermal expansion of solid materials is presented. The proposed method is based on performing a digital image correlation between thermal images recorded at different temperatures by means of an infrared camera. It allows the coefficient of thermal expansion of both isotropic and anisotropic solid materials to be determined by measuring simultaneously the fractional increase in length and the actual thermal field over a small region of interest in which a dual-emissivity stochastic speckle pattern has been created. The results reported in this paper prove the effectiveness of the proposed method that can be applied either to carry out reference measurements in laboratory or to evaluate thermal stresses and strains on structural components in-field.
Interplay between computable measures of entanglement and other quantum correlations
Girolami, Davide; Adesso, Gerardo
2011-11-15
Composite quantum systems can be in generic states characterized not only by entanglement but also by more general quantum correlations. The interplay between these two signatures of nonclassicality is still not completely understood. In this work we investigate this issue, focusing on computable and observable measures of such correlations: entanglement is quantified by the negativity N, while general quantum correlations are measured by the (normalized) geometric quantum discord D{sub G}. For two-qubit systems, we find that the geometric discord reduces to the squared negativity on pure states, while the relationship D{sub G}{>=}N{sup 2} holds for arbitrary mixed states. The latter result is rigorously extended to pure, Werner, and isotropic states of two-qudit systems for arbitrary d, and numerical evidence of its validity for arbitrary states of a qubit and a qutrit is provided as well. Our results establish an interesting hierarchy, which we conjecture to be universal, between two relevant and experimentally friendly nonclassicality indicators. This ties in with the intuition that general quantum correlations should at least contain and in general exceed entanglement on mixed states of composite quantum systems.
Correlating Function and Imaging Measures of the Medial Longitudinal Fasciculus
Sakaie, Ken; Takahashi, Masaya; Remington, Gina; Wang, Xiaofeng; Conger, Amy; Conger, Darrel; Dimitrov, Ivan; Jones, Stephen; Frohman, Ashley; Frohman, Teresa; Sagiyama, Koji; Togao, Osamu
2016-01-01
Objective To test the validity of diffusion tensor imaging (DTI) measures of tissue injury by examining such measures in a white matter structure with well-defined function, the medial longitudinal fasciculus (MLF). Injury to the MLF underlies internuclear ophthalmoparesis (INO). Methods 40 MS patients with chronic INO and 15 healthy controls were examined under an IRB-approved protocol. Tissue integrity of the MLF was characterized by DTI parameters: longitudinal diffusivity (LD), transverse diffusivity (TD), mean diffusivity (MD) and fractional anisotropy (FA). Severity of INO was quantified by infrared oculography to measure versional disconjugacy index (VDI). Results LD was significantly lower in patients than in controls in the medulla-pons region of the MLF (p < 0.03). FA was also lower in patients in the same region (p < 0.0004). LD of the medulla-pons region correlated with VDI (R = -0.28, p < 0.05) as did FA in the midbrain section (R = 0.31, p < 0.02). Conclusions This study demonstrates that DTI measures of brain tissue injury can detect injury to a functionally relevant white matter pathway, and that such measures correlate with clinically accepted evaluation indices for INO. The results validate DTI as a useful imaging measure of tissue integrity. PMID:26800522
Measurement and correlation of jet fuel viscosities at low temperatures
NASA Technical Reports Server (NTRS)
Schruben, D. L.
1985-01-01
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.
Lee, Jin Bae; Chang, Sung Gug; Kim, So Yeon; Lee, Young Soo; Ryu, Jae Kean; Choi, Ji Yong; Kim, Kee Sik; Park, Jae Sik
2012-10-01
The aim of the study was to assess the accuracy of the three-dimensional (3D) quantitative coronary analysis (QCA) system by comparing with that of intravascular ultrasound (IVUS) QCA and two-dimensional (2D) QCA. 3D QCA, 2D QCA and IVUS QCA were performed in 45 vessel segments. The obtained values for the branch to branch segment vessel length and the proximal part of the segment vessel's lumen diameter were measured. Inter-technique agreement was analyzed using paired sample t-test and Bland-Altman analysis. No differences were found in vessel lengths taken by 3D QCA and IVUS QCA (mean difference: 0.29 1.06 mm, P = 0.07). When compared with IVUS QCA, 2D QCA underestimated vessel length (mean difference: -1.78 2.55, P < 0.001). Bland-Altman analysis showed close agreement and a small bias between 3D QCA and IVUS QCA in the measurement of vessel length. The vessel lumen diameter measurements by 2D QCA and 3D QCA were significantly lower than that by IVUS QCA (mean difference: -0.64 0.69, P < 0.001; -0.56 0.52, P < 0.001 respectively). Rotational angiography with 3D reconstruction can provide a more accurate vessel length measurement, whereas 2D and 3D QCA underestimated the vessel lumen diameter compared with IVUS QCA. PMID:22179945
Collinge, Cory A; Koerner, John D; Yoon, Richard S; Beltran, Michael J; Liporace, Frank A
2015-10-01
Insertion of locking screws through the proximal thigh while locking retrograde femoral nails is arguably more difficult and traumatic to local tissues than locking at other intramedullary nail sites. The purpose of this study was to evaluate whether a "standard" screw length for proximal interlocking of retrograde nails is possible, therefore assessing whether the act of measuring for these screws can be omitted. This article retrospective evaluates screw position and estimated proximal locking screw length in patients undergoing retrograde nailing using a large radiographically measured computed tomography cohort, with validation through a smaller clinical cohort. According to these data, it seems reasonable to skip depth gauge measurement during anteroposterior interlocking of retrograde femoral nails and insert a standard length screw based on location relative to the lesser trochanter. This should decrease the amount of local trauma to the patient at the locking screw site while increasing operating room efficiency by avoiding what can often become a difficult step during the procedure. PMID:25946415
Applications of correlation and quantum entanglement to optical measurement
NASA Astrophysics Data System (ADS)
Simon, David S.
Entangled-photon methods have led to a number of new techniques and effects in optical imaging, communication, and measurement. These range from dispersion cancelation techniques to ghost imaging and quantum lithography. Although all of these methods made use of entangled quantum systems in their original forms, in some cases it has since been found that similar effects can be reproduced with the entangled-photon pairs replaced by classically correlated beams. The goal in this thesis is to develop a cluster of new methods using entangled photon pairs or classically-correlated light beams for applications in optical imaging and measurement. In each of these methods, the photons are detected pairwise by two detectors connected via a coincidence circuit. Thus, the devices to he described have correlated or entangled biphoton states, rather than individual photons, as their basic operating unit. The major theme running through the proposed applications is that correlation and entanglement allow unprecedented control over the phases of these pairs. This control allows useful new effects that are impossible in devices whose operation depends on the detection of individual photons. The applications discussed fall into three general categories. First we show that by arranging for pairwise phase cancelations we may reduce or eliminate a number of distorting influences, allowing improved image quality and reduced noise. Within this category, we will concentrate on the cancelation of optical turbulence caused by passage of light through fluids and on cancelation of static abberations introduced by passage through an optical system. The second category of application is microscopy. Two new devices (the correlation confocal microscope and twin-photon microscope) are described which make use of pairwise phase correlations to improve lateral resolution in confocal microscopy. These differ from each other and from the standard two-photon microscope by the manner in which the correlation is imposed. Finally, the third category of application involves the characterization of periodic structures on the surfaces of materials. Two techniques (quantum scatterometry and holographic scatterometry) are proposed to enhance nonimaging surface structure characterization by means of correlated photon methods.
Babichenko, V. S. Kagan, Yu.
2012-11-15
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.
Beta Neutrino Correlation Measurement with Trapped Radioactive Ions
Velten, Ph.; Ban, G.; Durand, D.; Flechard, X.; Lienard, E.; Mauger, F.; Naviliat-Cuncic, O.; Thomas, J.-C.
2010-04-30
The beta-neutrino angular correlation coefficient provides a sensitive observable to search for physics beyond the standard electroweak model in nuclear beta decay. We address here the measurement of this parameter in the pure Gamow-Teller transition of {sup 6}He. A deviation from the standard model prediction would indicate the existence of tensor like couplings, possibly mediated by new bosons like leptoquarks. The aim of the LPCTrap experiment is to measure this coefficient with a statistical uncertainty of 0.5% using a novel transparent Paul trap. The status of the experiment is briefly presented along with the work in progress.
Measurement of correlated b quark cross sections at CDF
Gerdes, D.; CDF Collaboration
1994-09-01
Using data collected during the 1992--93 collider run at Fermilab, CDF has made measurements of correlated b quark cross section where one b is detected from a muon from semileptonic decay and the second b is detected with secondary vertex techniques. We report on measurements of the cross section as a function of the momentum of the second b and as a function of the azimuthal separation of the two b quarks, for transverse momentum of the initial b quark greater than 15 GeV. Results are compared to QCD predictions.
Leng, X; Starchev, K; Buffle, J
2001-10-01
Diffusion dynamics of a polysaccharide, schizophyllan has been studied by fluorescence correlation spectroscopy (FCS). Several different sizes of nondenatured and denatured schizophyllan have been labeled with rhodamine 6G in borate buffer. The length of the nondenatured schizophyllan was calculated from FCS data by using the Broersma's relationship for rod-like macromolecules. The obtained length was close to that obtained by atomic force microscopy (AFM) measurements. Denatured schizophyllan possesses a random coil conformation. Its hydrodynamic radius R(h) was measured by FCS. The relationship between R(h) and the molecular mass M has been studied and the scaling relationship R(h)--M(0.59) has been obtained, which is in agreement with the random coil model with excluded volume effect. The persistence length q(denat) of the denatured schizophyllan was determined by Hearst's relationship, to be equal to 5.16 +/- 0.75 (nm). The work demonstrates the utility of FCS method for dynamics investigations of biopolymers especially in diluted regime (concentration lower than 10(-8)M could be measured) where other techniques could not be used. PMID:11473353
Chen, C F; Tixier-Boichard, M
2003-05-01
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
NASA Astrophysics Data System (ADS)
Huska, Dalibor; Adam, Vojtech; Trnkova, Libuse; Kizek, Rene
2009-05-01
The main aim of this work was to study the dependence of oligoadenine isolation efficiency on the chain length by using paramagnetic particles covered by homo-deoxythymidines ((dT)25) with subsequent detection by adsorptive transfer technique coupled with square wave voltammetry. For this purpose, the oligonucleotides of the length A5, A10, A15, A20, A25, A30, A35, A40 and poly(A) in various concentrations were chosen. We determined that the isolation efficiency defined as "isolated oligonucleotide concentration"/"given oligonucleotide concentration" was about 55% on average. Sequence A25 demonstrated the best binding onto microparticles surface.
3D shape measurement with phase correlation based fringe projection
NASA Astrophysics Data System (ADS)
Kühmstedt, Peter; Munckelt, Christoph; Heinze, Matthias; Bräuer-Burchardt, Christian; Notni, Gunther
2007-06-01
Here we propose a method for 3D shape measurement by means of phase correlation based fringe projection in a stereo arrangement. The novelty in the approach is characterized by following features. Correlation between phase values of the images of two cameras is used for the co-ordinate calculation. This work stands in contrast to the sole usage of phase values (phasogrammetry) or classical triangulation (phase values and image co-ordinates - camera raster values) for the determination of the co-ordinates. The method's main advantage is the insensitivity of the 3D-coordinates from the absolute phase values. Thus it prevents errors in the determination of the co-ordinates and improves robustness in areas with interreflections artefacts and inhomogeneous regions of intensity. A technical advantage is the fact that the accuracy of the 3D co-ordinates does not depend on the projection resolution. Thus the achievable quality of the 3D co-ordinates can be selectively improved by the use of high quality camera lenses and can participate in improvements in modern camera technologies. The presented new solution of the stereo based fringe projection with phase correlation makes a flexible, errortolerant realization of measuring systems within different applications like quality control, rapid prototyping, design and CAD/CAM possible. In the paper the phase correlation method will be described in detail. Furthermore, different realizations will be shown, i.e. a mobile system for the measurement of large objects and an endoscopic like system for CAD/CAM in dental industry.
Bonczek, R R; Richardson, D O; Moore, E D; Miller, R H; Owen, J R; Dowlen, H H; Bell, B R
1992-01-01
Growth and body measurements from a long-term selection project were analyzed to determine correlated responses to single-trait selection for milk yield. Data were from 1056 daughters (765 selection, 291 control) of 37 bulls (17 selection, 20 control) of 37 bulls (17 selection, 20 control) and included BW and measures of heart girth, chest depth, wither height, and length from withers to pins and from withers to hooks taken at 6 mo, 15 mo, first calving, end of first lactation, and maturity. Other data were birth weight, change in measurements and weights from first calving to end of first lactation, monthly rate of gain from 1 to 13 mo of age, and age reaching breeding weight (250 kg). Principal component scores were calculated from standardized measurements at each age. The first three principal components has meaning (size, length vs. girth, and height vs. girth). All analyses used linear mixed models with fixed effects of genetic group, generation within group, year-season of birth or calving, parity of dam, and birth status (multiple or single birth). Sires were assumed to be random and nested within genetic group. Mean squares for sires was used to test for group differences. Generation did not differ in any analysis and was removed from all models. Selection cows were heavier, larger in some measurements, and had greater overall size at 6 mo of age. Selection cows had greater monthly rate of gain and attained breeding weight at an earlier age. Genetic groups did not differ for any other measurement or weight. Control cows gained more weight and increased more in some measurements between first calving and end of first lactation. Selection for milk yield did not result in an undesirable correlated response in an growth or body measurement. PMID:1541738
Shchelkunov, S.V.; Marshall, T.C.; Hirshfield, J.L.; LaPointe, M.A.
2004-12-07
We report progress in the development of a nondestructive technique to measure bunch rms-length in the psec range and below, and eventually in the fsec range, by measuring the high-frequency spectrum of wake field radiation which is caused by the passage of a relativistic electron bunch through a channel surrounded by a dielectric. We demonstrate both experimentally and numerically that the generated spectrum is determined by the bunch rms-length, while the choice of the axial and longitudinal charge distribution is not important. Measurement of the millimeter-wave spectrum will determine the bunch rms-length in the psec range. This has been done using a series of calibrated mesh filters and the charge bunches produced by the 50MeV rf linac system at ATF, Brookhaven. We have developed the analysis of the factors crucial for achieving good accuracy in this measurement, and find the experimental data are fully understood by the theory. We point out that this technique also may be used for measuring fsec bunch lengths, using a prepared planar wake field microstructure.
Wada, Kenji; Matsukura, Satoru; Tanaka, Amaka; Matsuyama, Tetsuya; Horinaka, Hiromichi
2015-09-01
A simple method to measure single-mode optical fiber lengths is proposed and demonstrated using a gain-switched 1.55-μm distributed feedback laser without a fast photodetector or an optical interferometer. From the variation in the amplified spontaneous emission noise intensity with respect to the modulation frequency of the gain switching, the optical length of a 1-km single-mode fiber immersed in water is found to be 1471.043915 m ± 33 μm, corresponding to a relative standard deviation of 2.2 × 10(-8). This optical length is an average value over a measurement time of one minute under ordinary laboratory conditions. PMID:26368406
Estimating correlation for a real-time measure of connectivity.
Arunkumar, Akhil; Panday, Ashish; Joshi, Bharat; Ravindran, Arun; Zaveri, Hitten P
2012-01-01
There has recently been considerable interest in connectivity analysis of fMRI and scalp and intracranial EEG time-series. The computational requirements of the pair-wise correlation (PWC), the core time-series measure used to estimate connectivity, presents a challenge to the real-time estimation of the PWC between all pairs of multiple time-series. We describe a parallel algorithm for computing PWC in real-time for streaming data from multiple channels. The algorithm was implemented on the Intel Xeon™ and IBM Cell Broadband Engine™ platforms. We evaluated time to estimate correlation for signals recorded with different acquisition parameters as a comparison to real-time constraints. We demonstrate that the execution time of these efficient implementations meet real-time constraints in most instances. PMID:23367098
Detecting correlated errors in state-preparation-and-measurement tomography
NASA Astrophysics Data System (ADS)
Jackson, Christopher; van Enk, S. J.
2015-10-01
Whereas in standard quantum-state tomography one estimates an unknown state by performing various measurements with known devices, and whereas in detector tomography one estimates the positive-operator-valued-measurement elements of a measurement device by subjecting to it various known states, we consider here the case of SPAM (state preparation and measurement) tomography where neither the states nor the measurement device are assumed known. For d -dimensional systems measured by d -outcome detectors, we find there are at most d2(d2-1 ) "gauge" parameters that can never be determined by any such experiment, irrespective of the number of unknown states and unknown devices. For the case d =2 we find gauge-invariant quantities that can be accessed directly experimentally and that can be used to detect and describe SPAM errors. In particular, we identify conditions whose violations detect the presence of correlations between SPAM errors. From the perspective of SPAM tomography, standard quantum-state tomography and detector tomography are protocols that fix the gauge parameters through the assumption that some set of fiducial measurements is known or that some set of fiducial states is known, respectively.
Measuring capital market efficiency: Global and local correlations structure
NASA Astrophysics Data System (ADS)
Kristoufek, Ladislav; Vosvrda, Miloslav
2013-01-01
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.
Photon-burst correlation techniques for atmospheric crosswind measurements
NASA Astrophysics Data System (ADS)
She, C. Y.; Kelley, R. F.
1983-09-01
With a CW visible laser, the method of photon-burst correlation is used to measure atmospheric crosswinds. A scaling law, including the effects of atmospheric turbulence, for performance evaluation of both laser Doppler (LDV) and laser time-of-flight (LTV) velocimeters, is introduced theoretically and established experimentally with field experiments. Crosswind measurements in the night at a range of 500 m with a low power argon-ion laser are reported. The measured signal particle arrival rate is consistent with the predicted arrival rate based on the scaling law. In addition to the use of higher laser power, it is suggested that with proper inclusion of signal photon bursts resulting from the simultaneous arrival of several particles, routine operation of this type of laser velocimeter for long ranges, up to 1000 m, should be feasible.
Photon-burst correlation techniques for atmospheric crosswind measurements
NASA Astrophysics Data System (ADS)
She, C. Y.; Kelley, R. F.
1984-04-01
With a cw visible laser, the method of photon-burst correlation is used measure atmospheric crosswinds. A scaling law, including the effects of atmospheric turbulence, for performance evaluation of both laser Doppler (LDV) and laser time-of-flight (LTV) velocimeters, is introduced theoretically and established experimentally with field experiments. Crosswind measurements in the night at a range of 500 m with a low-power argon-ion laser are reported. The measured signal particle arrival rate is consistent with the predicted arrival rate based on the scaling law. In addition to the use of higher laser power, it is suggested that with proper inclusion of signal photon bursts resulting from the simultaneous arrival of several particles, routine operation of this type of laser velocimeter for long ranges, up to 1000m, should be feasible.
Correlating index properties of rocks with P-wave measurements
NASA Astrophysics Data System (ADS)
Khandelwal, Manoj; Ranjith, P. G.
2010-05-01
The determination of index properties of rock, such as Cerchar Abrasivity Index, Shore Hardness, Protodyakonov Index and Vickers Hardness in laboratory or insitu conditions is time-consuming and requires special equipment and expertise. However, the use of P-wave technology to measure the P-wave velocity of rock is a relatively simple task because the portable equipment can be used in the laboratory or in the field without tedious preparation of rock cores and it is non-destructive. This paper presents an experimental study of the measurement of P-waves of several types of igneous, sedimentary and metamorphic rock. The index properties were also determined in the laboratory to obtain correlations between P-waves and various index properties. Good linear relationships were found between all the index properties determined and the P-wave measurements.
Measurement of helicopter rotor blade deformation using digital image correlation
NASA Astrophysics Data System (ADS)
Sirohi, Jayant; Lawson, Michael S.
2012-04-01
An experimental study on the application of the digital image correlation (DIC) technique to measure the deformation of rotating helicopter blades is described. Measurements on two different rotors of diameter 24 and 39 in., with different rotor hubs, were carried out to explore applicability of the technique over a range of scales. Commercial DIC software was synchronized with the frequency of rotation such that rotor blade images could be obtained at a constant rotor azimuth. Bending and torsion mode shapes were extracted from the data with deformation as high as 0.4 in. measured with an accuracy of 0.0038 in. This technique is very advantageous because it is noncontact, cost effective, accurate and simple to implement while yielding full-field, three-dimensional data with a high spatial resolution.
NASA Astrophysics Data System (ADS)
Ray, Suman; Chakrabarti, Sandip Kumar; Sasmal, Sudipta
We present results of year-long analysis of VLF signals, both for VTX-Malda (`west-east' propagation path) and VTX-Pune (`east-west' propagation path). We analyzed whole year data of 2008 and 2009 for VTX-Malda and VTX-Pune propagation path, respectively. In both the cases we found that `VLF day-length' (defined as time difference between sunset terminator time and sunrise terminator time) became anomalously high 1-2 days before an earthquake. Besides this year-long study we have also done some case by case analysis. On 9th January, 2009 an earthquake of magnitude 5.5 occurred at Carlsberg Ridge (latitude 10.3(°) N, longitude 57.1(°) E). In a separate incident, on 3rd November, 2009, another earthquake of magnitude 5.4 occurred at Andaman Islands (latitude 14.1(°) N, longitude 93.1(°) E). We analyze VLF signals for VTX-Pune (`east-west’ propagation path) propagation path around these two earthquake days and found that for both of these cases, the `VLF-day-length' became anomalously high two days before the event. This agrees well with statistical analysis based on year-long data for VTX-Pune path. Furthermore, during time period of June, 2010, two major earthquakes of low-depth ( 10Km) and high magnitude (M>5) occurred near NWC-Salt Lake (east-west propagation path) propagation paths. First one occurred on 13th June, 2010 at Nicobar Islands, India (latitude 7.8(°) N, longitude 92.0(°) E). Its magnitude was 5.1 (in Richter scale). The second one of magnitude 6.0 (in Richter Scale) occurred on 19th June, 2010 at Andaman Islands, India (latitude 13.4(°) N, longitude 93.0(°) E). For both of these two earthquakes, we found that VLF-day-length, became anomalously high one day before earthquakes. We claim that these were pre-cursors of the earthquakes which occurred in Andaman and Nicober Islands.
NASA Technical Reports Server (NTRS)
Sonwalker, V. S.; Inan, U. S.
1986-01-01
A new experimental technique is developed to simultaneously measure the wave propagation direction and the effective length of a small (L value much smaller than wavelength) electric dipole antenna on a spin-stabilized satellite in the magnetosphere. The technique relies on the near simultaneous measurement of single components of the electric and magnetic fields of a coherent VLF signal injected into the medium from a ground-based source. The spin fading characteristics of the signal received by the electric dipole and the magnetic loop antenna permit the measurement of the wave normal direction assuming whistler-mode propagation. In-situ and remote measurements of the local cold plasma density are used to determine the refractive index. The wave electric field is then inferred from the wave magnetic field as measured on the loop antenna, the refractive index and the direction of propagation. Comparing this electric field with the measured voltage across the dipole antenna leads to the determination of the effective length of the receiving electric dipole. The technique is applied to data from the Dynamics Explorer 1 satellite observations of whistler mode signals injected into the magnetosphere from the Siple, Antarctica, VLF transmitter. In one case, with the measured background cold plasma density being 15 el/cu cm, the effective length of the 200 m-long electric dipole antenna is found to be 222 + or - 56 m, i.e., about twice the conventional value.
Heme Carbonyls: Environmental Effects on νC–O and Fe–C/C–O Bond Length Correlations
Silvernail, Nathan J.; Roth, Arne; Noll, Bruce C.; Scheidt, W. Robert; Schulz, Charles E.
2006-01-01
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 νC–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 νC–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 π 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
Consistent scaling of multifractal measures: Multifractal spatial correlations
NASA Astrophysics Data System (ADS)
Platt, Daniel E.; Family, Fereydoon
1993-04-01
There are a number of apparently disparate problems in multifractal scaling whose solutions have remained unclear, ranging from rather pathological cases where the standard Legendre transformations do not produce effective measures for the Hölder exponent and Hausdorff-Besicovitch dimension to the problem of describing the scaling of point-point correlation functions of moments of multifractal measures. We prove that an equivalent statement of multifractal scaling is the invariance of the generating functions of the scaling transformation. We show that the invariance of the generating functions is what allows the moment integrals to scale with simple power laws. We show that this definition can be successfully extended to cover the scaling of point-point correlation functions of moments of multifractal measures. Previous attempts to solve this problem have lead to non-scale-invariant behavior, presented as an inconsistency by Cates and Deutsch [Phys. Rev. A 35, 4907 (1987)]. We propose that the invariance of generating functions under their own transformations is the central defining characteristic of scale invariance in multifractal scaling.
Directional correlation measurements for gamma transitions in /sup 127/Te
de Souza, M.O.M.D.; Saxena, R.N.
1985-02-01
The directional correlation of coincident ..gamma.. transitions in /sup 127/Te has been measured following the ..beta../sup -/ decay of /sup 127/Sb (T/sub 1/2/ = 3.9 d) using Ge(Li)-Ge(Li) and Ge(Li)-NaI(T1) gamma spectrometers. Measurements have been carried out for 14 gamma cascades resulting in the determination of multipole mixing ratios delta(E2/M1) for 15 ..gamma.. transitions. The present results permitted a definite spin assignment of (7/2) for the 785 keV level and confirmation of several previous assignments to other levels in /sup 127/Te. The g factor of the 340 keV ((9/2)/sup -/) level has also been measured using the integral perturbed angular correlation method in the hyperfine magnetic field of a Te in Ni matrix. The results of the g factor as well as the mixing ratio for the 252 keV ((9/2)/sup -/..-->..(11/2)/sup -/) transition support the earlier interpretation of this state as an anomalous coupling state.
NASA Astrophysics Data System (ADS)
Gao, Long; Yu, Bo-Xiang; Ding, Ya-Yun; Zhou, Li; Wen, Liang-Jian; Xie, Yu-Guang; Wang, Zhi-Gang; Cai, Xiao; Sun, Xi-Lei; Fang, Jian; Xue, Zhen; Zhang, Ai-Wu; L, Qi-Wen; Sun, Li-Jun; Ge, Yong-Shuai; Liu, Ying-Biao; Niu, Shun-Li; Hu, Tao; Cao, Jun; L, Jun-Guang
2013-07-01
An attenuation length measurement device was constructed using an oscilloscope and LabVIEW for signal acquisition and processing. The performance of the device has been tested in 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 a gadolinium-loaded liquid scintillator (Gd-LS) was measured as 15.100.35 m where Gd-LS was heavily used in the 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.
Measurements of 3D slip velocities and plasma column lengths of a gliding arc discharge
NASA Astrophysics Data System (ADS)
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
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.
Measurements of 3D slip velocities and plasma column lengths of a gliding arc discharge
Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas; Aldén, Marcus; Li, Zhongshan E-mail: alpers@ma.tum.de; Moseev, Dmitry; Kusano, Yukihiro; Salewski, Mirko; Alpers, Andreas E-mail: alpers@ma.tum.de; Gritzmann, Peter; Schwenk, Martin
2015-01-26
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.
Sannibale, Fernando; Zolotorev, Max S.; Filippetto, Daniele; Stupakov, Gennady V.
2007-06-22
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.
Water Velocity Measurement on an Extended-Length Submerged Bar Screen at John Day Dam
Weiland, Mark A.; Escher, Charles
2001-04-02
This report describes a study of water velocity around an extended-length submerged bar screen (ESBS) at John Day Dam. The study was conducted for the U.S. Army Corps of Engineers by AScI Corporation and MEVATEC Corporation in March of 2000. This report was prepared by Pacific Northwest National Laboratory. ESBS are being studied as one method for diverting juvenile migrating fish from the dam's turbine intakes into the gate well and through the juvenile fish bypass channels.
ERIC Educational Resources Information Center
Tan-Sisman, Gulcin; Aksu, Meral
2012-01-01
"Knowing and doing measurement" is a fundamental competency in real life since measuring attributes of objects in appropriate units and using measuring tools assist students to quantify and understand the world. For this reason, the study of measurement has a special place in every mathematics curriculum. Among the domains of measurement, length…
Some measurements of time and space correlation in wind tunnel
NASA Technical Reports Server (NTRS)
Favre, A; Gaviglio, J; Dumas, R
1955-01-01
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.
Intensity and angular correlation measurements of /sup 103/Ru
Darwish, S.M.; Abdel-Malak, S.; Abou-Leila, M.A.; Walley-Eldin, N.; Hassan, A.M.
1987-01-01
The level scheme of /sup 103/Rh was investigated using a HPGe detector and a Ge(Li)-NaI(Tl) coincidence spectrometer. Four new transitions were observed, confirmed, and fitted into a proposed level scheme. The ..beta../sup -/ branching ratios and the log ft values were obtained. A measurement of the 513.98--53.3-keV ..gamma gamma.. angular correlation using a HPGe-NaI(Tl) fast coincidence spectrometer yielded the spin assignment 7/2 for the 607.2-keV level and a multipole mixing ratio E1+9.83%M2 for the 513.98-keV ..gamma.. transition.
Karmakar, Chandan; Udhayakumar, Radhagayathri K; Palaniswami, Marimuthu
2015-08-01
Heart rate complexity analysis is a powerful non-invasive means to diagnose several cardiac ailments. Non-linear tools of complexity measurement are indispensable in order to bring out the complete non-linear behavior of Physiological signals. The most popularly used non-linear tools to measure signal complexity are the entropy measures like Approximate entropy (ApEn) and Sample entropy (SampEn). But, these methods become unreliable and inaccurate at times, in particular, for short length data. Recently, a novel method of complexity measurement called Distribution Entropy (DistEn) was introduced, which showed reliable performance to capture complexity of both short term synthetic and short term physiologic data. This study aims to i) examine the competence of DistEn in discriminating Arrhythmia from Normal sinus rhythm (NSR) subjects, using RR interval time series data; ii) explore the level of consistency of DistEn with data length N; and iii) compare the performance of DistEn with ApEn and SampEn. Sixty six RR interval time series data belonging to two groups of cardiac conditions namely `Arrhythmia' and `NSR' have been used for the analysis. The data length N was varied from 50 to 1000 beats with embedding dimension m = 2 for all entropy measurements. Maximum ROC area obtained using ApEn, SampEn and DistEn were 0.83, 0.86 and 0.94 for data length 1000, 1000 and 500 beats respectively. The results show that DistEn undoubtedly exhibits a consistently high performance as a classification feature in comparison with ApEn and SampEn. Therefore, DistEn shows a promising behavior as bio marker for detecting Arrhythmia from short length RR interval data. PMID:26737465
NASA Astrophysics Data System (ADS)
Duncan, J. L.; Harvie, J. L.; McKean, D. C.; Cradock, S.
1986-07-01
Infrared spectra of the molecules Si 2HD 5, SiHD 2CH 3, SiH 3CHD 2, SiHD 2X (X = F, Cl, Br, I) have been recorded at 0.05 cm -1 resolution. Analyses of "perpendicular" fundamentals of these very slightly asymmetric top molecules permit the accurate determination of their ground state ( A0— B0) constants, from which the A 0 rotational constants may be obtained. When combined with all known Raman and microwave constants, this enables the ground state structures to be determined with precision, allowance being made for the shortening of SiH(CH) bonds on deuteration. For disilane this work represents the first spectroscopic determination of a complete structure, while for the silyl halides it demonstrates overestimates in the SiH bond length of nearly 1% by previous workers. In the case of methyl silane, comparison with a recent ab initio structure calculation reveals a considerable overestimate of the CSi bond length in the latter. A correlation between isolated SiH stretching frequency and ground state bond length over 15 molecules reveals a somewhat reduced sensitivity compared with the corresponding CH correlation. Nevertheless, a predictive capability of better than ±0.003 Å seems possible from the isolated SiH stretching frequency, at least for molecules with fully saturated bonding.
Efficient measurement of point-to-set correlations and overlap fluctuations in glass-forming liquids
NASA Astrophysics Data System (ADS)
Berthier, Ludovic; Charbonneau, Patrick; Yaida, Sho
2016-01-01
Cavity point-to-set correlations are real-space tools to detect the roughening of the free-energy landscape that accompanies the dynamical slowdown of glass-forming liquids. Measuring these correlations in model glass formers remains, however, a major computational challenge. Here, we develop a general parallel-tempering method that provides orders-of-magnitude improvement for sampling and equilibrating configurations within cavities. We apply this improved scheme to the canonical Kob-Andersen binary Lennard-Jones model for temperatures down to the mode-coupling theory crossover. Most significant improvements are noted for small cavities, which have thus far been the most difficult to study. This methodological advance also enables us to study a broader range of physical observables associated with thermodynamic fluctuations. We measure the probability distribution of overlap fluctuations in cavities, which displays a non-trivial temperature evolution. The corresponding overlap susceptibility is found to provide a robust quantitative estimate of the point-to-set length scale requiring no fitting. By resolving spatial fluctuations of the overlap in the cavity, we also obtain quantitative information about the geometry of overlap fluctuations. We can thus examine in detail how the penetration length as well as its fluctuations evolve with temperature and cavity size.
Berthier, Ludovic; Charbonneau, Patrick; Yaida, Sho
2016-01-14
Cavity point-to-set correlations are real-space tools to detect the roughening of the free-energy landscape that accompanies the dynamical slowdown of glass-forming liquids. Measuring these correlations in model glass formers remains, however, a major computational challenge. Here, we develop a general parallel-tempering method that provides orders-of-magnitude improvement for sampling and equilibrating configurations within cavities. We apply this improved scheme to the canonical Kob-Andersen binary Lennard-Jones model for temperatures down to the mode-coupling theory crossover. Most significant improvements are noted for small cavities, which have thus far been the most difficult to study. This methodological advance also enables us to study a broader range of physical observables associated with thermodynamic fluctuations. We measure the probability distribution of overlap fluctuations in cavities, which displays a non-trivial temperature evolution. The corresponding overlap susceptibility is found to provide a robust quantitative estimate of the point-to-set length scale requiring no fitting. By resolving spatial fluctuations of the overlap in the cavity, we also obtain quantitative information about the geometry of overlap fluctuations. We can thus examine in detail how the penetration length as well as its fluctuations evolve with temperature and cavity size. PMID:26772579
Kapoor, Veena; Hakim, Fran T; Rehman, Najibah; Gress, Ronald E; Telford, William G
2009-05-15
Telomere length analysis has been greatly simplified by the quantitative flow cytometry technique FISH-flow. In this method, a fluorescein-labeled synthetic oligonucleotide complementary to the telomere terminal repeat sequence is hybridized to the telomere sequence and the resulting fluorescence measured by flow cytometry. This technique has supplanted the traditional laborious Southern blot telomere length measurement techniques in many laboratories, and allows single cell analysis of telomere length in high-throughput sample formats. Nevertheless, the harsh conditions required for telomere probe annealing (82 degrees C) has made it difficult to successfully combine this technique with simultaneous immunolabeling. Most traditional organic fluorescent probes (i.e. fluorescein, phycoerythrin, etc.) have limited thermal stability and do not survive the high temperature annealing process, despite efforts to covalently crosslink the antigen-antibody-fluorophore complex. This loss of probe fluorescence has made it difficult to measure FISH-flow in complex lymphocyte populations, and has generally forced investigators to use fluorescent-activated cell sorting to pre-separate their populations, a laborious technique that requires prohibitively large numbers of cells. In this study, we have substituted quantum dots (nanoparticles) for traditional fluorophores in FISH-flow. Quantum dots were demonstrated to possess much greater thermal stability than traditional low molecular weight and phycobiliprotein fluorophores. Quantum dot antibody conjugates directed against monocyte and T cell antigens were found to retain most of their fluorescence following the high temperature annealing step, allowing simultaneous fluorescent immunophenotyping and telomere length measurement. Since quantum dots have very narrow emission bandwidths, we were able to analyze multiple quantum dot antibody conjugates (Qdot 605, 655 and 705) simultaneously with FISH-flow measurement to assess the age-associated decline in telomere length in both human monocytes and T cell subsets. With quantum dot immunolabeling, the mean decrease rate in telomere length for CD4+ cells was calculated at 41.8 bp/year, very close to previously reported values using traditional flow-FISH and Southern blotting. This modification to the traditional flow-FISH technique should therefore allow simultaneous fluorescent immunophenotyping and telomere length measurement, permitting complex cell subset-specific analysis in small numbers of cells without the requirement for prior cell sorting. PMID:19268672
The Effect of Error Correlation on Interfactor Correlation in Psychometric Measurement
ERIC Educational Resources Information Center
Westfall, Peter H.; Henning, Kevin S. S.; Howell, Roy D.
2012-01-01
This article shows how interfactor correlation is affected by error correlations. Theoretical and practical justifications for error correlations are given, and a new equivalence class of models is presented to explain the relationship between interfactor correlation and error correlations. The class allows simple, parsimonious modeling of error…
3D robust digital image correlation for vibration measurement.
Chen, Zhong; Zhang, Xianmin; Fatikow, Sergej
2016-03-01
Discrepancies of speckle images under dynamic measurement due to the different viewing angles will deteriorate the correspondence in 3D digital image correlation (3D-DIC) for vibration measurement. Facing this kind of bottleneck, this paper presents two types of robust 3D-DIC methods for vibration measurement, SSD-robust and SWD-robust, which use a sum of square difference (SSD) estimator plus a Geman-McClure regulating term and a Welch estimator plus a Geman-McClure regulating term, respectively. Because the regulating term with an adaptive rejecting bound can lessen the influence of the abnormal pixel data in the dynamical measuring process, the robustness of the algorithm is enhanced. The robustness and precision evaluation experiments using a dual-frequency laser interferometer are implemented. The experimental results indicate that the two presented robust estimators can suppress the effects of the abnormality in the speckle images and, meanwhile, keep higher precision in vibration measurement in contrast with the traditional SSD method; thus, the SWD-robust and SSD-robust methods are suitable for weak image noise and strong image noise, respectively. PMID:26974624
Baggett, F J; Mackie, I C; Worthington, H V
1996-08-10
A study was undertaken to determine if a tactile technique, using absorbent paper points, could be used to estimate the working length of nonvital immature incisor teeth undergoing endodontic treatment. Two operators were involved in measuring 35 incisor teeth. The tactile technique was found to be valid and reliable. In 95% of the cases the estimated working length was within 1 mm of the radiographic diagnostic length. It is recommended that diagnostic radiographs are no longer necessary in the majority of cases involving endodontic treatment of incisor teeth requiring root end closure in children, for practitioners who are regularly carrying out endodontic treatment of immature incisor teeth. However, if a tooth has been on open drainage a diagnostic radiograph is still required. PMID:8810108
Image correlation spectroscopy for measurements of particle densities and colocalization.
Rappaz, Benjamin; Wiseman, Paul W
2013-06-01
Cells interact with their environment through receptor proteins expressed at their plasma membrane, and protein-protein interactions govern the transduction of signals across the membrane into the cell. Therefore, the ability to measure receptor densities and protein colocalization within the membrane of intact cells is of paramount importance. This unit describes a technique to extract these parameters from fluorescence microscopy images obtained using a commercial confocal laser scanning microscope (CLSM) and other similar types of microscopes. It is based on the analysis of spatial fluorescence intensity fluctuations in the images, which can then be related to particle density and aggregation state via calculation of a spatial autocorrelation function, or used to measure particle colocalization via calculation of a spatial cross-correlation function from dual-color images of proteins tagged with two different fluorophores and imaged in two detection channels. These parameters offer key insights on the interaction of the cell with its environment. PMID:23728747
Shaw, A.; Ghosh, A.
2014-10-28
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 BO{sub 4} units has been established for different compositions of the borotellurite glasses.
Strongly correlated two-dimensional plasma explored from entropy measurements.
Kuntsevich, A Y; Tupikov, Y V; Pudalov, V M; Burmistrov, I S
2015-01-01
Charged plasma and Fermi liquid are two distinct states of electronic matter intrinsic to dilute two-dimensional electron systems at elevated and low temperatures, respectively. Probing their thermodynamics represents challenge because of lack of an adequate technique. Here, we report a thermodynamic method to measure the entropy per electron in gated structures. Our technique appears to be three orders of magnitude superior in sensitivity to a.c. calorimetry, allowing entropy measurements with only 10(8) electrons. This enables us to investigate the correlated plasma regime, previously inaccessible experimentally in two-dimensional electron systems in semiconductors. In experiments with clean two-dimensional electron system in silicon-based structures, we traced entropy evolution from the plasma to Fermi liquid regime by varying electron density. We reveal that the correlated plasma regime can be mapped onto the ordinary non-degenerate Fermi gas with an interaction-enhanced temperature-dependent effective mass. Our method opens up new horizons in studies of low-dimensional electron systems. PMID:26099565
Two-particle correlation measurements in p+Nb reactions ?sNN = 3.18 GeV
NASA Astrophysics Data System (ADS)
Arnold, Oliver
2016-01-01
We present a two-particle correlation measurement of proton- and of ?p-pairs, measured with the HADES detector in p+Nb reactions at a kinetic beam energy of 3.5 GeV. The proton-proton correlation function is used to extract the size of the region of homogeneity. Using this information together with a UrQMD transport simulation opens the possibility to study the interaction of ?p pairs in terms of spin average scattering length and effective range.
NASA Technical Reports Server (NTRS)
Cliff, W. C.; Skarda, J. R.
1987-01-01
NASA's Airborne Doppler Lidar System has been used to obtain a detailed 'instantaneous' mapping of horizontal spatial wind fields at 600-800 m elevations on the east side of the San Gorgonio Pass in California, in the form of checkerboard-fashion horizontal wind vectors spaced at 300 m intervals along and normal to the flight path. Spatial autocorrelations for the lateral and longitudinal components are ensemble-averaged, and integral turbulent length scales are computed for the wind fields' longitudinal and lateral directions. The flow in the region studied does not appear to be isotropic.
NASA Astrophysics Data System (ADS)
Kim, Kang; Saito, Shinji
2013-03-01
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 α-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 α-relaxation time in tetrahedral network-forming strong liquid, even at lower temperatures.
Nguyen, Uyen-Sa D.T.; Kiel, Douglas P.; Li, Wenjun; Galica, Andrew M.; Kang, Hyun Gu; Casey, Virginia A.; Hannan, Marian T.
2012-01-01
Objective Impaired balance is associated with falls in older adults. However, there is no accepted gold standard on how balance should be measured. Few studies have examined measures of postural sway and clinical balance concurrently in large samples of community-dwelling older adults. We examined the associations among four types of measures of laboratory- and clinic-based balance in a large population-based cohort of older adults. Methods We evaluated balance measures in the MOBILIZE Boston Study (276 men, 489 women, 6497 years). Measures included: (1) laboratory-based anteroposterior (AP) path length and average sway speed, mediolateral (ML) average sway and root-mean-square, and area of ellipse postural sway; (2) Short Physical Performance Battery (SPPB); (3) Berg Balance Scale; and (4) one-leg stand. Spearman Rank Correlation Coefficients (r) were assessed among the balance measures. Results Area of ellipse sway was highly correlated with the ML sway measures (r >0.9, p < 0.0001), and sway speed was highly correlated with AP sway (r=0.97, p < 0.0001). The Berg Balance Scale was highly correlated with SPPB (r=0.7, p<0.001), and one-leg stand (r=0.8, p<0.001). Correlations between the laboratory- and clinic-based balance measures were low but statistically significant (0.2 < r < 0.3, p<0.0001). Conclusion Clinic-based balance measures, and laboratory-based measures comparing area of ellipse with ML sways or sway speed with AP sway, are highly correlated. Clinic- with laboratory-based measures are less correlated. As both laboratory- and clinic-based measures inform balance in older adults but are not highly correlated with each other, future work should investigate the differences. PMID:22745045
Forde, Elizabeth; Booth, Jeremy; Leech, Michelle
2014-07-01
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.
NASA Astrophysics Data System (ADS)
Koelemeij, J. C. J.; Leduc, M.
2004-11-01
A numerical investigation of two-laser photoassociation (PA) spectroscopy on spin-polarized metastable helium (He*) atoms is presented within the context of experimental observation of the least-bound energy level in the scattering potential and subsequent determination of the s-wave scattering length. Starting out from the model developed by Bohn and Julienne [Phys. Rev. A 60, 414 (1999)], PA rate coefficients are obtained as a function of the parameters of the two lasers. The rate coefficients are used to simulate one- and two-laser PA spectra. The results demonstrate the feasibility of a spectroscopic determination of the binding energy of the least-bound level. The simulated spectra may be used as a guideline when designing such an experiment, whereas the model may also be employed for fitting experimentally obtained PA spectra. In addition, the prospects for substantial modification of the He* scattering length by means of optical Feshbach resonances are considered. Several experimental issues relating to the numerical investigation presented here are discussed.
Measurement of laminar burning speeds and Markstein lengths using a novel methodology
Tahtouh, Toni; Halter, Fabien; Mounaim-Rousselle, Christine
2009-09-15
Three different methodologies used for the extraction of laminar information are compared and discussed. Starting from an asymptotic analysis assuming a linear relation between the propagation speed and the stretch acting on the flame front, temporal radius evolutions of spherically expanding laminar flames are postprocessed to obtain laminar burning velocities and Markstein lengths. The first methodology fits the temporal radius evolution with a polynomial function, while the new methodology proposed uses the exact solution of the linear relation linking the flame speed and the stretch as a fit. The last methodology consists in an analytical resolution of the problem. To test the different methodologies, experiments were carried out in a stainless steel combustion chamber with methane/air mixtures at atmospheric pressure and ambient temperature. The equivalence ratio was varied from 0.55 to 1.3. The classical shadowgraph technique was used to detect the reaction zone. The new methodology has proven to be the most robust and provides the most accurate results, while the polynomial methodology induces some errors due to the differentiation process. As original radii are used in the analytical methodology, it is more affected by the experimental radius determination. Finally, laminar burning velocity and Markstein length values determined with the new methodology are compared with results reported in the literature. (author)
Correlates of objectively measured physical activity in cardiac patients
Ozemek, Cemal; Riggin, Katrina; Strath, Scott; Kaminsky, Leonard
2014-01-01
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
NASA Astrophysics Data System (ADS)
Morey, A. E.; Goldfinger, C.; Erhardt, M.; Nelson, C. H.; Johnson, J. E.; Gutierrez-Pastor, J.
2005-12-01
We are using multiple proxies, including XRF analysis, to determine hemipelagic thickness between turbidite events recorded in cores along the offshore northern San Andreas margin. Inter-event times are calculated from these improved estimates of sediment thickness and regression-determined sedimentation rates, and used along with known stratigraphic information to constrain calibrated radiocarbon age ranges using Bayesian statistical methods within the program OxCal. OxCal can also be used to combine multiple ages for the same event. Multiple ages are given "credit" where age ranges overlap, resulting in reduced 1- or 2-sigma age ranges compared to averaging peak ages and propagating errors. These methods reduce calendar age variability of events along strike that are thought to correlate. We tested three methods of estimating calendar ages, using the most recent events in a Noyo Canyon core. These methods are: 1. unconstrained radiocarbon age calibration, 2. age determination using known dates and inter-event time calculated from hemipelagic thickness and the regression-determined sedimentation rate, and 3. (preferred method) use OxCal's sequence option to calibrate and constrain radiocarbon ages given all available stratigraphic information, including date of collection, historical or geological datums, inter-event times and radiocarbon ages. The upper-most event was chosen for these tests because it is known to be the 1906 earthquake and the 20th century reservoir correction is well known in this area. The penultimate event was chosen because it has been dated at multiple land sites. 1906 event: Unconstrained calibration: calibration of the radiocarbon age of the 1906 event yields an age of ~1913, (1σ: 1898-1940). Sedimentation time: subtracting the time represented by the hemipelagic thickness above the 1906 event from the date of collection (1999) yields an age of ~1904. OxCal sequence: constrained calibration yields an age of ~1902 (1σ: 1880-1910). Penultimate event: Unconstrained calibration: calibration of this radiocarbon age yields an age of ~1753 (1σ: 1660-1840). Sedimentation time: subtracting the time represented by the hemipelagic thickness below the 1906 event from 1906 yields an age of ~1756. OxCal sequence: constrained calibration yields an age of ~1700 (1σ: 1650-1735), in good agreement with adjacent northern SAF paleoseismic sites on land: Fort Ross = 1710 (1610-1810), Vedanta =1711 (1695-1720) (T. Niemi, K. Kelson, and T. Fumal pers. com. 2005). The close correspondence in time of our SAF penultimate event and the AD 1700 Cascadia event suggests the possibility that the Noyo Canyon site may have recorded the Cascadia event, ~ 130 km away, however we find that the penultimate event in Noyo Canyon is well correlated southward to at least Point Arena, too far to be related to the Cascadia event. We also continue to refine inter-site physical property correlation methods in parallel with radiocarbon ages. Depositional patterns within events, recorded as magnetic susceptibility, chemical, and density patterns, match at widely separated sites in surprising detail. Both individual event signatures, and the downcore stratigraphic patterns are both highly unique and strongly comparable from site.
NASA Astrophysics Data System (ADS)
Pan, Xiaotao; Shi, Xianke; Korzh, Vladimir; Yu, Hanry; Wohland, Thorsten
2009-03-01
The flow direction of microfluidics in biological applications is not limited to two dimensions, but often extends to three dimensions. Currently there are optical methods available for the measurement of 3-D microfluidic flow vectors, but with low spatial resolution. Line scan fluorescence correlation spectroscopy (FCS) was proposed to determine flow directions in 2-D within microchannels and small blood vessels in our previous work. Importantly, its spatial resolution was demonstrated to be as good as 0.5 μm. In this work, we extend line scan FCS to the third dimension for the characterization of 3-D flow velocity vectors. The spatial resolution is close to the diffraction limit using a scan length of 0.5 μm in all three dimensions. The feasibility of line scan FCS for 3-D microfluidic flow is verified by measurements in microchannels and small blood vessels of zebrafish embryos.
NASA Astrophysics Data System (ADS)
Iinuma, Masataka; Suzuki, Yutaro; Nii, Taiki; Kinoshita, Ryuji; Hofmann, Holger F.
2016-03-01
In general, it is difficult to evaluate measurement errors when the initial and final conditions of the measurement make it impossible to identify the correct value of the target observable. Ozawa proposed a solution based on the operator algebra of observables which has recently been used in experiments investigating the error-disturbance trade-off of quantum measurements. Importantly, this solution makes surprisingly detailed statements about the relations between measurement outcomes and the unknown target observable. In the present paper, we investigate this relation by performing a sequence of two measurements on the polarization of a photon, so that the first measurement commutes with the target observable and the second measurement is sensitive to a complementary observable. While the initial measurement can be evaluated using classical statistics, the second measurement introduces the effects of quantum correlations between the noncommuting physical properties. By varying the resolution of the initial measurement, we can change the relative contribution of the nonclassical correlations and identify their role in the evaluation of the quantum measurement. It is shown that the most striking deviation from classical expectations is obtained at the transition between weak and strong measurements, where the competition between different statistical effects results in measurement values well outside the range of possible eigenvalues.
NASA Astrophysics Data System (ADS)
Patil, Abhijit A.; Pandey, Yogendra Narayan; Doxastakis, Manolis; Stein, Gila E.
2014-10-01
The acid-catalyzed deprotection of glassy poly(4-hydroxystyrene-co-tertbutyl acrylate) films was studied with infrared absorbance spectroscopy and stochastic simulations. Experimental data were interpreted with a simple description of subdiffusive acid transport coupled to second-order acid loss. This model predicts key attributes of observed deprotection rates, such as fast reaction at short times, slow reaction at long times, and a nonlinear dependence on acid loading. Fickian diffusion is approached by increasing the postexposure bake temperature or adding plasticizing agents to the polymer resin. These findings demonstrate that acid mobility and overall deprotection kinetics are coupled to glassy matrix dynamics. To complement the analysis of bulk kinetics, acid diffusion lengths were calculated from the anomalous transport model and compared with nanopattern line widths. The consistent scaling between experiments and simulations suggests that the anomalous diffusion model could be further developed into a predictive lithography tool.
NASA Astrophysics Data System (ADS)
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
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.
Tunable non-local entanglement of electrons probed by noise cross-correlation measurement
NASA Astrophysics Data System (ADS)
Wei, Jian
2010-03-01
Nonlocal entanglement is crucial for quantum information processes. While nonlocal entanglement has been realized for photons, it is much more difficult to demonstrate for electrons. One approach that has been proposed is to use hybrid superconducting/normal-metal devices. When the distance between two normal-metal electrodes connected to a superconductor is comparable to the superconducting coherence length, theory predicts that two electrons in the normal-metal electrodes with opposite spin are entangled by Cooper pairs, leading to non-local entanglement of electrons. Such entanglement can be understood by a non-local process called crossed Andreev reflection (CAR), in which a Cooper pair splits into two coherent electrons with one in each normal-metal electrode, generating instantaneous current of the same sign, and inducing a positive current correlation. Experimentally, CAR is indicated by a negative non-local resistance. However, another non-local process, elastic cotunneling (EC), in which one electron tunnels through the superconductor from one normal-metal electrode to the other, contributes to a positive non-local resistance that cancels the contribution due to CAR, preventing us from measuring and control of the CAR component. Fortunately, EC leads to a negative current correlation with bias dependence different from that of CAR. Thus, noise correlation measurement is expected to be able to distinguish these two non-local processes. By cross-correlation measurements as well as measurements of the local and nonlocal resistance, we present here experimental evidence showing that by independently controlling the energy of electrons at the superconductor/normal-metal interfaces, nonlocal Andreev reflection, the signature of spin-entanglement, can be maximized, qualitatively in agreement with theoretical predication.
NASA Technical Reports Server (NTRS)
Vonroos, O. H. (Inventor)
1978-01-01
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.
NASA Astrophysics Data System (ADS)
Michel, D. T.; Davis, A. K.; Goncharov, V. N.; Sangster, T. C.; Hu, S. X.; Igumenshchev, I. V.; Meyerhofer, D. D.; Seka, W.; Froula, D. H.
2015-04-01
Measurements of the conduction-zone length (110 ±20 μ m at t =2.8 ns ), the averaged mass ablation rate of the deuterated plastic (7.95 ±0.3 μ g /ns ), shell trajectory, and laser absorption are made in direct-drive cryogenic implosions and are used to quantify the electron thermal transport through the conduction zone. Hydrodynamic simulations that use nonlocal thermal transport and cross-beam energy transfer models reproduce these experimental observables. Hydrodynamic simulations that use a time-dependent flux-limited model reproduce the measured shell trajectory and the laser absorption but underestimate the mass ablation rate by ˜10 % and the length of the conduction zone by nearly a factor of 2.
Advances in Air-Sea Flux Measurement by Eddy Correlation
NASA Astrophysics Data System (ADS)
Blomquist, Byron W.; Huebert, Barry J.; Fairall, Christopher W.; Bariteau, Ludovic; Edson, James B.; Hare, Jeffrey E.; McGillis, Wade R.
2014-09-01
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.
Viscosity Measurements and Correlation of the Squalane + CO2 Mixture
NASA Astrophysics Data System (ADS)
Tomida, D.; Kumagai, A.; Yokoyama, C.
2007-02-01
Experimental results for the viscosity of squalane + CO2 mixtures are reported. The viscosities were measured using a rolling ball viscometer. The experimental temperatures were 293.15, 313.15, 333.15, and 353.15 K, and pressures were 10.0, 15.0, and 20.0 MPa. The CO2 mole fraction of the mixtures varied from 0 to 0.417. The experimental uncertainties in viscosity were estimated to be within ±3.0%. The viscosity of the mixtures decreased with an increase in the CO2 mole fraction. The experimental data were compared with predictions from the Grunberg-Nissan and McAllister equations, which correlated the experimental data with maximum deviations of 10 and 8.7%, respectively.
openBEB: open biological experiment browser for correlative measurements
2014-01-01
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
Quantifying Path Length: Fourth-Grade Children's Developing Abstractions for Linear Measurement
ERIC Educational Resources Information Center
Barrett, Jeffrey E.; Clements, Douglas H.
2003-01-01
This article describes how children build increasingly abstract knowledge of linear measurement, emphasizing ways they relate space and number. Assessments indicate children struggle to understand measurement, especially concepts related to complex paths as in perimeter tasks. This article draws on developmental accounts of children's knowledge of…
Wang, Shuai; Luo, Xuenong; Wei, Wei; Zheng, Yadong; Dou, Yongxi; Cai, Xuepeng
2013-01-01
Individual genes or regions are still commonly used to estimate the phylogenetic relationships among viral isolates. The genomic regions that can faithfully provide assessments consistent with those predicted with full-length genome sequences would be preferable to serve as good candidates of the phylogenetic markers for molecular epidemiological studies of many viruses. Here we employed a statistical method to evaluate the evolutionary relationships between individual viral genes and full-length genomes without tree construction as a way to determine which gene can match the genome well in phylogenetic analyses. This method was performed by calculation of linear correlations between the genetic distance matrices of aligned individual gene sequences and aligned genome sequences. We applied this method to the phylogenetic analyses of porcine circovirus 2 (PCV2), measles virus (MV), hepatitis E virus (HEV) and Japanese encephalitis virus (JEV). Phylogenetic trees were constructed for comparisons and the possible factors affecting the method accuracy were also discussed in the calculations. The results revealed that this method could produce results consistent with those of previous studies about the proper consensus sequences that could be successfully used as phylogenetic markers. And our results also suggested that these evolutionary correlations could provide useful information for identifying genes that could be used effectively to infer the genetic relationships. PMID:24312527
Kalron, Alon
2016-02-01
There is a general consensus relating to the multidimensional aspects of fatigue in people with multiple sclerosis (PwMS), however, the exact impact of this symptom on gait is not fully understood. Our primary aim was to examine the relationship between definite parameters of gait with self-reported symptomatic fatigue in PwMS according to their level of neurological impairment. Spatio-temporal parameters of gait were studied using an electronic walkway. The Multiple Sclerosis Walking Scale (MSWS-12) questionnaire, a patient-rated measure of walking ability was collected. The Modified Fatigue Impact Scale (MFIS) questionnaire was used to determine the level of symptomatic fatigue. One hundred and one PwMS (61 women) were included in the study analysis. Subjects were divided into mild and moderate neurological impaired groups. Fatigue was correlated with 5 (out of 14) spatiotemporal parameters. However, correlation scores were all <0.35, thus considered as weak correlations. In the mild group, the double support period was the only variable positively correlated to fatigue (Spearman's rho=0.28, P=0.05). In the moderate group, step and stride length were solely negatively correlated to fatigue (Spearman's rho=0.32, P=0.03). In contrast to the definite gait parameters, the MSWS-12 self-questionnaire was moderately positively correlated to the level of fatigue. Scores for the total, mild and moderate groups were 0.54, 0.57 and 0.51; P<0.01, respectively. The present results indicate that modifications in spatio-temporal parameters of gait are not closely related to symptomatic fatigue in PwMS. On the contrary, the self-reported MSWS-12 questionnaire is predisposed to level of fatigue in PwMS. PMID:27004654
Water equivalent path length measurement in proton radiotherapy using time resolved diode dosimetry
Gottschalk, B.; Tang, S.; Bentefour, E. H.; Cascio, E. W.; Prieels, D.; Lu, H.-M.
2011-04-15
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.
Length scales in alloy dissolution and measurement of absolute interfacial free energy.
Rugolo, J; Erlebacher, J; Sieradzki, K
2006-12-01
De-alloying is the selective dissolution of one or more of the elemental components of an alloy. In binary alloys that exhibit complete solid solubility, de-alloying of the less noble component results in the formation of nanoporous metals, a materials class that has attracted attention for applications such as catalysis, sensing and actuation. In addition, the occurrence of de-alloying in metallic alloy systems under stress is known to result in stress-corrosion cracking, a key failure mechanism in fossil fuel and nuclear plants, ageing aircraft, and also an important concern in the design of nuclear-waste storage containers. Central to the design of corrosion-resistant alloys is the identification of a composition-dependent electrochemical critical potential, Vcrit, above which the current rises dramatically with potential, signalling the onset of bulk de-alloying. Below Vcrit, the surface is passivated by the accumulation of up to several monolayers of the more noble component. The current understanding of the processes that control Vcrit is incomplete. Here, we report on de-alloying results of Ag/Au superlattices that clarify the role of pre-existing length scales in alloy dissolution. Our data motivated us to re-analyse existing data on critical potentials of Ag-Au alloys and develop a simple unifying picture that accounts for the compositional dependence of solid-solution alloy critical potentials. PMID:17099702
Ning, Peng; Li, Sa; White, Philip J.; Li, Chunjian
2015-01-01
Larger, and deeper, root systems of new maize varieties, compared to older varieties, are thought to have enabled improved acquisition of soil resources and, consequently, greater grain yields. To compare the spatial distributions of the root systems of new and old maize varieties and their relationships with spatial variations in soil concentrations of available nitrogen (N), phosphorus (P) and potassium (K), two years of field experiments were performed using six Chinese maize varieties released in different eras. Vertical distributions of roots, and available N, P and K in the 0–60 cm soil profile were determined in excavated soil monoliths at silking and maturity. The results demonstrated that new maize varieties had larger root dry weight, higher grain yield and greater nutrient accumulation than older varieties. All varieties had similar total root length and vertical root distribution at silking, but newer varieties maintained greater total root length and had more roots in the 30–60 cm soil layers at maturity. The spatial variation of soil mineral N (Nmin) in each soil horizon was larger than that of Olsen-P and ammonium-acetate-extractable K, and was inversely correlated with root length density (RLD), especially in the 0–20 cm soil layer. It was concluded that greater acquisition of mineral nutrients and higher yields of newer varieties were associated with greater total root length at maturity. The negative relationship between RLD and soil Nmin at harvest for all varieties suggests the importance of the spatial distribution of the root system for N uptake by maize. PMID:25799291
Ning, Peng; Li, Sa; White, Philip J; Li, Chunjian
2015-01-01
Larger, and deeper, root systems of new maize varieties, compared to older varieties, are thought to have enabled improved acquisition of soil resources and, consequently, greater grain yields. To compare the spatial distributions of the root systems of new and old maize varieties and their relationships with spatial variations in soil concentrations of available nitrogen (N), phosphorus (P) and potassium (K), two years of field experiments were performed using six Chinese maize varieties released in different eras. Vertical distributions of roots, and available N, P and K in the 0-60 cm soil profile were determined in excavated soil monoliths at silking and maturity. The results demonstrated that new maize varieties had larger root dry weight, higher grain yield and greater nutrient accumulation than older varieties. All varieties had similar total root length and vertical root distribution at silking, but newer varieties maintained greater total root length and had more roots in the 30-60 cm soil layers at maturity. The spatial variation of soil mineral N (Nmin) in each soil horizon was larger than that of Olsen-P and ammonium-acetate-extractable K, and was inversely correlated with root length density (RLD), especially in the 0-20 cm soil layer. It was concluded that greater acquisition of mineral nutrients and higher yields of newer varieties were associated with greater total root length at maturity. The negative relationship between RLD and soil Nmin at harvest for all varieties suggests the importance of the spatial distribution of the root system for N uptake by maize. PMID:25799291
NASA Astrophysics Data System (ADS)
Taulbee, Timothy D.
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.
Flap noise characteristics measured by pressure cross correlation techniques
NASA Astrophysics Data System (ADS)
Miller, W. R.
1980-03-01
The aerodynamic sound generated by a realistic aircraft flap system was investigated through the use of cross correlations between surface pressure fluctuations and far field sound. Measurements were conducted in two subsonic wind tunnel studies to determine the strength, distribution, and directivity of the major sources of flap noise at speeds up to 79.0 m/sec. A pilot study was performed on a single flap model to test the measurement technique and provide initial data on the characteristics of flap noise. The major portion of this investigation studied the sound radiated by a realistic large scale model of a triple slotted flap system mounted on a sweptback 6.7 meter semispan model wing. The results of this investigation have identified the major sources of flap generated noise and their dependence of flow defining parameters. In addition, a possible avenue toward the reduction of flap generated noise has been identified via the placement of the flap actuator fairings on the flap system.
Measuring β- ν angular correlation with laser trapped 6He
NASA Astrophysics Data System (ADS)
Leredde, Arnaud; Bailey, Kevin; Mueller, Peter; O'Connor, Thomas; Bagdasarova, Yelena; Garcia, Alejandro; Hong, Ran; Sternberg, Matthew; Storm, Derek; Swanson, Erik; Wauters, Frederik; Zumwalt, David W.; Flechard, Xavier; Lienard, Etienne; Knetch, Andreas; Naviliat-Cuncic, Oscar
2014-09-01
Exotic current contributions to the weak interaction can be constrained through measuring the beta-neutrino angular correlation parameter aβν in nuclear beta decay - providing opportunities to find evidence for physics beyond the Standard Model. Our goal is to measure aβν with a precision of 0.1% for the beta decay of 6He (t1/2 = 807 ms) which is particularly sensitive to the exotic tensor currents. For this purpose, we have built a double magneto-optical trap (MOT) system to provide a cold and point-like source of 6He. Of the 1x1010 6He atoms/s produced via the 7Li(d,3He)6He nuclear reaction, roughly 1000 atoms/s are captured in the first MOT and periodically transferred to the second, low background MOT that is surrounded by a detector system. Coincidence detection of the beta particle and the recoiling ion offers kinematic reconstruction of aβν in combination with high statistic numerical simulations of the detector setup. The performance of the trap setup, preliminary coincidence data, and studies of systematic uncertainties will be presented. This work is supported by DOE, Office of Nuclear Physics, under contract nos. DE-AC02-06CH11357 and DE-FG02-97ER41020.
Correlated Protein Motion Measurements of Dihydrofolate Reductase Crystals
NASA Astrophysics Data System (ADS)
Xu, Mengyang; Niessen, Katherine; Pace, James; Cody, Vivian; Markelz, Andrea
2014-03-01
We report the first direct measurements of the long range structural vibrational modes in dihydrofolate reductase (DHFR). DHFR is a universal housekeeping enzyme that catalyzes the reduction of 7,8-dihydrofolate to 5,6,7,8-tetra-hydrofolate, with the aid of coenzyme nicotinamide adenine dinucleotide phosphate (NADPH). This crucial enzymatic role as the target for anti-cancer [methotrexate (MTX)], and other clinically useful drugs, has made DHFR a long-standing target of enzymological studies. The terahertz (THz) frequency range (5-100 cm-1), corresponds to global correlated protein motions. In our lab we have developed Crystal Anisotropy Terahertz Microscopy (CATM), which directly measures these large scale intra-molecular protein vibrations, by removing the relaxational background of the solvent and residue side chain librational motions. We demonstrate narrowband features in the anisotropic absorbance for mouse DHFR with the ligand binding of NADPH and MTX single crystals as well as Escherichia coli DHFR with the ligand binding of NADPH and MTX single crystals. This work is supported by NSF grant MRI2 grant DBI2959989.
NASA Astrophysics Data System (ADS)
Boulesteix, Thierry; Beaurepaire, Emmanuel; Sauviat, Martin-Pierre; Schanne-Klein, Marie-Claire
2004-09-01
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.
Measurement of the minority carrier diffusion length and edge surface-recombination velocity in InP
NASA Technical Reports Server (NTRS)
Bailey, Sheila G.; Hakimzadeh, Roshanak
1993-01-01
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).
NASA Astrophysics Data System (ADS)
Steyn-Ross, Moira L.; Steyn-Ross, D. A.; Sleigh, J. W.; Whiting, D. R.
2003-08-01
In a recent series of papers, the authors have developed a stochastic theory to describe the electrical response of a spatially homogeneous cerebral cortex to infusion of a general anesthetic agent. We showed that by modeling the GABAergic (propofol-like) drug effect as a prolongation of the inhibitory postsynaptic impulse response, we obtain a prediction that there will be a hysteretically separated pair of first-order phase transitions in the population-average excitatory soma voltage, the first occurring at the point of induction of unconsciousness, and the second at the point of emergence from unconsciousness. In the present paper we generalize our earlier “zero-dimensional” homogeneous cortex to a one-dimensional (1D) line of cortical “mass,” thus allowing for the possibility of spatial inhomogeneities in neural activity. Following the spirit of our earlier adiabatic (“slow membrane”) philosophy, we impose a spatioadiabatic approximation that permits us to compute analytic expressions for changes in EEG (electroencephalographic) correlation length and EEG spatial covariance as a function of anesthetic effect. We establish that the correlation length of the EEG fluctuations is expected to increase at the approach to the transition points, and this finding is consistent with both the homogeneous-cortex prediction of increased correlation time (“critical slowing down”) near transition, and the recent, comprehensive anesthetic study by John et al. [Conscious. Cogn. 10, 165 (2001)] reporting an increase in EEG coherence near the points of loss and recovery of consciousness. In addition, we find that if the long-range (corticocortical) excitatory-to-inhibitory connectivity in the 1D cortex is stronger than the long-range excitatory-to-excitatory connectivity, then the spatioadiabatic system can organize itself into large-amplitude spatial patterns (“dissipative structures”) consisting of giant stationary quasiperiodic voltage fluctuations distributed along the cortical rod.
Brown, Dean P; Brown, Thomas G
2008-12-01
Correlations in the illumination field have a profound impact on the image contrast for features near the resolution limit. The pupil polarization affects these correlations. We show that a polarization vortex has a particularly dramatic effect. A theoretical model is given for the correlation matrix of a partially correlated source created by placing an azimuthal polarization vortex mode converter in the pupil plane of a critical illumination system. We then validate this model experimentally using a reversed-wavefront Young interferometer, directly show the impact that the phase of the correlation function has on image contrast. PMID:19065180
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
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
Udhayakumar, Radhagayathri K; Karmakar, Chandan; Peng Li; Palaniswami, Marimuthu
2015-08-01
Complexity analysis of a given time series is executed using various measures of irregularity, the most commonly used being Approximate entropy (ApEn), Sample entropy (SampEn) and Fuzzy entropy (FuzzyEn). However, the dependence of these measures on the critical parameter of tolerance `r' leads to precarious results, owing to random selections of r. Attempts to eliminate the use of r in entropy calculations introduced a new measure of entropy namely distribution entropy (DistEn) based on the empirical probability distribution function (ePDF). DistEn completely avoids the use of a variance dependent parameter like r and replaces it by a parameter M, which corresponds to the number of bins used in the histogram to calculate it. When tested for synthetic data, M has been observed to produce a minimal effect on DistEn as compared to the effect of r on other entropy measures. Also, DistEn is said to be relatively stable with data length (N) variations, as far as synthetic data is concerned. However, these claims have not been analyzed for physiological data. Our study evaluates the effect of data length N and bin number M on the performance of DistEn using both synthetic and physiologic time series data. Synthetic logistic data of `Periodic' and `Chaotic' levels of complexity and 40 RR interval time series belonging to two groups of healthy aging population (young and elderly) have been used for the analysis. The stability and consistency of DistEn as a complexity measure as well as a classifier have been studied. Experiments prove that the parameters N and M are more influential in deciding the efficacy of DistEn performance in the case of physiologic data than synthetic data. Therefore, a generalized random selection of M for a given data length N may not always be an appropriate combination to yield good performance of DistEn for physiologic data. PMID:26738118
Tao, X. D.; Feng, Z.; Miao, B. F.; Sun, L.; You, B.; Wu, D.; Du, J.; Zhang, W.; Ding, H. F.
2014-05-07
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.
NASA Astrophysics Data System (ADS)
Loudon, James; Yazdi, S.; Kasama, T.; Zhigadlo, N. D.; Karpinski, J.
2015-03-01
We demonstrate that images of flux vortices in a superconductor taken with a transmission electron microscope can be used to measure simultaneously the penetration depth and coherence length in all directions at the same temperature and magnetic field. This is particularly useful for MgB2 where these quantities vary with the applied magnetic field and values are difficult to obtain at low field or in the c direction. We obtained images of flux vortices from a sample cut in the ac plane by focussed ion beam milling and compared these with simulations which accounted for flux vortices with a non-zero core in a thin, anisotropic superconductor. This gave penetration depths ?ab = 100 +/- 35 nm, ?c = 120 +/- 15 nm and coherence lengths ?ab = 41 +/- 13 nm and ?c = 34 +/- 10 nm at 10.8 K in a field of 4.8 mT. The implications of these values for type-1.5 superconductivity will be discussed.
Evaluation of Length-of-Stain Gas Indicator Tubes for Measuring Carbon Monoxide in Air.
ERIC Educational Resources Information Center
Klaubert, Earl C.; And Others
Techniques for detection and measurement of carbon monoxide (CO) in air are of interest and utility in many aspects of automotive safety. CO concentrations may range from less than 100 parts per million (ppm), or 0.01 percent, to about 10 percent by volume. Gas indicator tubes have been used for many years primarily as detectors of hazardous gases
Evaluation of Length-of-Stain Gas Indicator Tubes for Measuring Carbon Monoxide in Air.
ERIC Educational Resources Information Center
Klaubert, Earl C.; And Others
Techniques for detection and measurement of carbon monoxide (CO) in air are of interest and utility in many aspects of automotive safety. CO concentrations may range from less than 100 parts per million (ppm), or 0.01 percent, to about 10 percent by volume. Gas indicator tubes have been used for many years primarily as detectors of hazardous gases…
The Difficulty of "Length x Width": Is a Square the Unit of Measurement?
ERIC Educational Resources Information Center
Kamii, Constance; Kysh, Judith
2006-01-01
In individual interviews, 220 students in grades 4, 6, 8, and 9 were given one task, and 72 eighth graders were given three tasks to answer two questions: (a) Is a square the unit of measurement for an area for students in grades 4-8? and (b) Does a square have a space-covering characteristic for students in grade 8? The answers to both questions…
Someswara Rao, Chinta; Viswanadha Raju, S.
2016-01-01
In this paper, we consider correlation coefficient, rank correlation coefficient and cosine similarity measures for evaluating similarity between Homo sapiens and monkeys. We used DNA chromosomes of genome wide genes to determine the correlation between the chromosomal content and evolutionary relationship. The similarity among the H. sapiens and monkeys is measured for a total of 210 chromosomes related to 10 species. The similarity measures of these different species show the relationship between the H. sapiens and monkey. This similarity will be helpful at theft identification, maternity identification, disease identification, etc.
Swimm, R.T.; Dumas, K.A.
1982-11-01
The optical absorption coefficient of silicon solar cell material grown by three low-cost growth methods was measured in the wavelength interval 0.8< or =lambda< or =1.0 ..mu..m, the wavelength region of interest in surface photovoltage measurements of the minority carrier diffusion length. The square root of the absorption coefficient was found to vary linearly with photon energy over the wavelengths studied, and the measured data agree with a linear empirical fit to within 0.5% RMS. The absorption coefficients obtained are slightly lower than those reported by Runyan, with the greatest disagreement at long wavelengths. Minority carrier diffusion lengths computed using the present absorption coefficients are approximately 16% greater than those calculated using Runyan's data. Excellent sample-to-sample agreement within and between lots indicates that for two of the growth methods studied, material quality as judged by optical properties has not been sacrificed by the use of low-cost growth methods. Samples grown by the third growth method studied showed measurably poorer optical quality.
Beta-Neutrino Correlation Measurements in 37K
NASA Astrophysics Data System (ADS)
Anholm, Melissa; Ashery, D.; Craiciu, I.; Behling, S.; Fenker, B.; Gorelov, A.; Gwinner, G.; Kurchaninov, L.; Mehlman, M.; Melconian, D.; Olchankski, K.; Shidling, P. D.; Smale, S.; Behr, J. A.; Trinat Collaboration
2013-10-01
The TRIUMF Neutral Atom Trap utilizes a unique set of techniques to obtain samples of cold, polarized atoms. We have been particularly interested in trapping 37K atoms, which decay by β+ emission in a mixed Fermi/Gamow-Teller transition to their isobaric analog, 37Ar. Because the higher-order standard model corrections to this decay process are well understood, it is ideal for for improving constraints on interactions beyond the standard model. By observing the daughter particles, we are sensitive to possible scalar, tensor, and right-handed vector currents in a process that is known to be predominantly a left-handed form of the weak interaction. Observations of overdetermined kinematics in the ion and β time-of-flight spectra allow us to reconstruct the neutrino flight paths, thereby providing an effective strategy for measuring the β-asymmetry parameter, the recoil asymmetry, the β-neutrino correlation, and the tensor alignment parameter. Here I focus primarily on the latter two. NSERC, NRC through TRIUMF, DOE ER41747 ER40773, State of Texas, Israel Science Foundation.
NASA Astrophysics Data System (ADS)
Makarevich, V.
2012-01-01
The COOMET Project No 507/BY/10, 'Supplementary comparison of length standards for measuring gear parameters', KCDB Reference COOMET.L-S10, was organized by the COOMET Technical Committee TC 1.5 'Length and Angle'. This comparison started in September 2010 and finished in September 2011. It was piloted by the Belarusian State Institute of Metrology, BelGIM, Minsk, the Republic of Belarus, with VNIIMS (Moscow, Russia) as the other participant. The transfer standard was a gear involute master provided by BelGIM. This standard has two base circle radii of 150 mm and 60 mm, and corresponding profiles on the left and on the right. The involute profile was measured from root towards tip of the tooth. The scanning was performed in automatic mode along the mid-section of the base cylinder over the complete estimation range, with a scanning speed of 2 mm s-1. The software program GEAR PRO involute was used to determine three parameters: the total profile deviation, the profile form deviation and the profile slope deviation. Each participant performed ten measurements for each of two involute profiles with basic circle radius of 150 mm and 60 mm, respectively. The measurement result for each parameter was calculated as a mean value from the ten measurements. The comparison results demonstrate that the measured values are consistent with the stated uncertainties and that the measurement standards under comparison are equivalent. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by COOMET, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).
Diverging Entanglement Length in Gapped Quantum Spin Systems
NASA Astrophysics Data System (ADS)
Verstraete, F.; Martin-Delgado, M. A.; Cirac, J. I.
2004-03-01
We study two-point correlations and the associated correlation length in spin chains from the point a view of quantum entanglement theory. We show how these correlations are lower bounds to the entanglement that can be localized between the spins under consideration by doing local measurements on all the other spins. This type of entanglement is especially useful in the context of quantum repeaters which play a central role in the field of quantum information theory. It follows that the correlation length is always a lower bound to the entanglement length. As an example, we consider so-called finitely correlated states (the ground states of AKLT-type Hamiltonians) and prove the existence of gapped quantum Hamiltonians whose ground states exhibit an infinite entanglement length (as opposed to their finite correlation length). We also discuss the case of finite temperatures and provide evidence for the diverging entanglement length in ground states of the spin-1 antiferromagnetic spin chain.
Bhardwaj, A.; Walker-Kopp, N; Casjens, S; Cingolani, G
2009-01-01
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.
NASA Astrophysics Data System (ADS)
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
We report a determination of the n -3He scattering length difference Δ 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 Δ 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 Δ 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.
2013-01-01
Background The prevalence of obesity in U.S. has been rising at an alarming rate, particularly among Hispanic, African, and Asian minority groups. This trend is due in part to excessive calorie consumption and sedentary lifestyle. We sought to investigate whether parental origins influence eating behaviors in healthy urban middle school students. Methods A multiethnic/racial population of students (N = 182) enrolled in the ROAD (Reduce Obesity and Diabetes) Study, a school-based trial to assess clinical, behavioral, and biochemical risk factors for adiposity and its co-morbidities completed questionnaires regarding parental origins, length of US residency, and food behaviors and preferences. The primary behavioral questionnaire outcome variables were nutrition knowledge, attitude, intention and behavior, which were then related to anthropometric measures of waist circumference, BMI z-scores, and percent body fat. Two-way analysis of variance was used to evaluate the joint effects of number of parents born in the U.S. and ethnicity on food preference and knowledge score. The Tukey-Kramer method was used to compute pairwise comparisons to determine where differences lie. Analysis of covariance (ANCOVA) was used to analyze the joint effects of number of parents born in the US and student ethnicity, along with the interaction term, on each adiposity measure outcome. Pearson correlation coefficients were used to examine the relationships between maternal and paternal length of residency in the US with measures of adiposity, food preference and food knowledge. Results African Americans had significantly higher BMI, waist circumference and body fat percentage compared to other racial and ethnic groups. Neither ethnicity/race nor parental origins had an impact on nutrition behavior. Mothers’ length of US residency positively correlated with students’ nutrition knowledge, but not food attitude, intention or behavior. Conclusions Adiposity measures in children differ according to ethnicity and race. In contrast, food behaviors in this middle school sample were not influenced by parental origins. Longer maternal US residency benefited offspring in terms of nutrition knowledge only. We suggest that interventions to prevent obesity begin in early childhood. PMID:24134822
NASA Astrophysics Data System (ADS)
Marone, Palma Ann; Thiyagarajan, P.; Wagner, Arlene M.; Tiede, David M.
1999-12-01
The effect of detergent alkyl chain length on the crystallization of detergent-solubilized membrane proteins was characterized using the reaction center (RC) from Rhodobacter sphaeroides as a model. Crystallization was performed in the presence of both n-alkyl-β-D-glucopyranosides, C nG, where the alkyl chain length, n, was varied from 8 to 10, and dodecyl-dimethylamine-N-oxide (C 12DAO). A pronounced effect of detergent chain length was found on the ability to crystallize the reaction center. Small-angle neutron scattering measurements (SANS) demonstrated that the variation in the ability to crystallize the reaction center is correlated with changes in the apparent radius of gyration, Rg, of the reaction center-detergent particle, reflecting changes in the size of the reaction center and strength of the inter-particle interactions. Specifically, reaction center crystallization in the absence of additional amphiphiles was found to occur only with octylglucoside, C 8G. Crystallization in the presence of longer chain detergents, C 9G, C 10G, C 12DAO, required the use of an additional small amphiphile, heptanetriol (HT). SANS measurements showed that the apparent Rg of the reaction center-detergent particle increased with increasing detergent chain length, and that the addition of HT reduces this parameter. The addition of HT was found to impede crystallization in the presence of C 8G. This inhibition could be reversed by increasing C 8G concentration with respect to HT, resulting in the formation of alternate crystal forms. Taken together, these results suggest that detergents and small molecule amphiphiles used in membrane protein crystallization must be chosen to optimize both the size and solubility of the protein-detergent particle. Data for the reaction center suggest that crystallization occurs within a restricted range of size of the protein-detergent complex.
NASA Astrophysics Data System (ADS)
Bai, M.; Taub, H.; Knorr, K.; Volkmann, U. G.; Hansen, F. Y.
2007-03-01
We have recently discovered that films of intermediate-length alkanes (n-CnH2n+2; 24 < n < 40) do not completely wet a SiO2 surface on a nanometer length scale [2]. In a narrow temperature range near the bulk melting point Tb, we observe a single layer of molecules oriented with their long axis perpendicular to the surface. On heating just above Tb, these molecules undergo a delayering transition to three-dimensional droplets that remain present up to their evaporation point. Here we report measurements by noncontact Atomic Force Microscopy of the contact angle of these droplets for a film of hexatriacontane (n-C36H74 or C36). Our preliminary measurements indicate that there is a weak maximum in the contact angle at ˜Tb + 3 C. Further measurements are planned to investigate whether the weak maximum in the contact angle is consistent with the droplets supporting a surface freezing effect as at the bulk fluid/air interface. ^2M. Bai, K. Knorr, M. J. Simpson, S. Trogisch, H. Taub, S. N. Ehrlich, H. Mo, U. G. Volkmann, F. Y. Hansen, cond-mat/0611497.
PRIOR GENETIC CORRELATIONS AND NON-MEASURED TRAITS
Technology Transfer Automated Retrieval System (TEKTRAN)
Current international genetic evaluations are based on how related country populations are genetically (across-country genetic correlations). Those correlations may be influenced strongly by prior expectations that were not based on sound scientific principles. Objective methods to predict prior cor...
Li, B.
2009-01-01
Sound velocity measurements at pressure and/or temperature provide important information in the material's structural behavior and physical properties under extreme conditions. With the application of synchrotron X-radiation sources, new developments have emerged to facilitate the study properties and structures of crystalline and amorphous materials. In the last decade, we have developed a unique technique for measuring sound velocity in a cubic type multianvil apparatus installed at X-17B2, National Synchrotron Light Source (NSLS) of Brookhaven National Lab, which allows us to conduct precise velocity measurements on crystalline and noncrystalline materials at various pressure and temperature conditions by conducting simultaneous X-radiation and ultrasonic interferometry measurements. In this paper, sound velocities at high temperatures for some ceramics and metals are measured to study the behavior and property change of these materials undergoing compression/expansion as well as phase transition and structural instabilities. This technique opens new opportunities for the study of materials that are of interest to many disciplines, such as earth science, materials science, and condensed matter physics.
Measuring Black Smoker Fluid Flow Rates Using Image Correlation Velocimetry
NASA Astrophysics Data System (ADS)
Crone, T. J.; Wilcock, W. S.; McDuff, R. E.
2006-12-01
Motivated by a desire to find non-invasive methods for obtaining time-series measurements of fluid flow rates through mid-ocean ridge black smokers, we are developing an image-based velocimetry technique that will provide this information through the analysis of video sequences showing the turbulent structures of black smoker effluent jets. Our ultimate goal is to develop an autonomous seafloor instrument suitable for use with a cabled seafloor observatory that can provide extended time-series measurements of black smoker discharge rates with little user intervention. The method we are developing is based on the two-dimensional cross-correlation of an array of overlapping subimages from two sequential image frames within a sequence. For each pair of images this yields a two- dimensional representation of the instantaneous velocity field in the imaged flow. For each video sequence, the set of these "image velocity fields" from all image pairs is temporally averaged to yield a smoothed representation of the time-averaged image flow field. A transformation is then applied to convert the image flow fields into a relative discharge rate. We have developed a computational algorithm to implement this technique and have successfully applied it to video sequences collected in the late 1980s and early 1990s showing the discharge of black smokers in the Main Endeavour field of the Juan de Fuca Ridge over the course of weeks and months. We are able to resolve velocity fields that are qualitatively consistent with those predicted by plume theory from 5 seconds of video (150 image pairs), but it is difficult to calibrate or assess the precision of the technique with field data alone. In order to address these issues, as well as refine the computational algorithm, we have conducted laboratory simulations of black smoker jets with known discharge rates over a range of Reynolds numbers. We have recorded these simulations to obtain video image sequences that are similar to those collected at the seafloor. We are currently applying our velocimetry technique to these video sequences. Early results suggest that robust estimates of black smoker discharge rate might be obtained through image-based velocimetry techniques.
Sack, Lawren; Caringella, Marissa; Scoffoni, Christine; Mason, Chase; Rawls, Michael; Markesteijn, Lars; Poorter, Lourens
2014-10-01
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
Vaisbuch, Edi; Romero, Roberto; Mazaki-Tovi, Shali; Erez, Offer; Kusanovic, Juan Pedro; Mittal, Pooja; Gotsch, Francesca; Ward, Clara; Romero, Vivian; Chaiworapongsa, Tinnakorn; Pacora, Percy; Yeo, Lami; Hassan, Sonia S.
2013-01-01
Objective To determine the pregnancy outcome of asymptomatic patients in the second trimester with a non-measurable cervical length (0 mm). Methods This retrospective cohort study included 78 patients with singleton pregnancies and a sonographic non-measurable cervix detected at 1428 weeks gestation. Patients with cervical cerclage were excluded. Results 1) 75.3% of the patients delivered before 32 weeks; 2) the median diagnosis-to-delivery interval was 20.5 days; the delivery rate within 7 and 14 days was 28.2% and 35.6%, respectively; 3) patients with a non-measurable cervix diagnosed <24 weeks had a shorter median diagnosis-to-delivery interval than those diagnosed at 2428 weeks (17.5 vs. 41 days; p=0.009). Conclusions 1) Asymptomatic women with a non-measurable cervix in the second trimester have a median diagnosis-to-delivery interval of ~3 weeks; 2) almost 65% of these patients will not deliver within two weeks, yet 75% deliver before 32 weeks; 3) the earlier a non-measurable cervix is identified the shorter the diagnosis-to-delivery interval. PMID:20659728
Ishikawa, K; Hayashi, T; Otani, S; Kanamasa, K; Yamakado, T; Osato, S; Tashi, M; Kohashi, Y; Katori, R
1981-06-01
Left ventricular size at different portions was evaluated following the administration of nitroglycerin to find whether there is any regional difference in the amount of shortening. In 6 patients with old myocardial infarction, biplane coronary cineangiograms were obtained before and after sublingual administration of nitroglycerin of 0.3 mg. The coordinates of the bifurcations of the left coronary artery at multiple sites were measured on the postero-anterior and lateral films and the spatial lengths (L) between any paired two points were calculated frame by frame covering one cardiac cycle. The maximum length (Lmax) was 63.2 +/- 3.1 (SE) mm before nitroglycerin as a whole and was 61.4 +/- 2.9 mm after nitroglycerin, showing no significant change. The minimum length (Lmin) also showed no significant change after nitroglycerin; from 56.1 +/- 2.9 to 54.9 +/- 2.6 mm. However, at the free wall, Lmax after nitroglycerin was reduced by 4.5 +/- 2.5%, and Lmax at the anterior septum was also reduced by 3.0 +/- 1.3%. Lmax at the base was unchanged after nitroglycerin. Lmin at the free wall and at the anterior septum were also reduced after nitroglycerin, 4.4 +/- 2.6 and 2.9 +/- 1.2%, respectively, and it was unchanged at the base. Since a reduction in the left ventricular size is effective in reducing myocardial oxygen demand and is effective in treating myocardial ischemia, it was suggested that nitroglycerin is more effective in relieving ischemia at the free wall and septum and less effective at the base. PMID:6798137
Benjamini, Dan; Basser, Peter J
2014-12-01
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. PMID:25481136
Measuring primordial anisotropic correlators with CMB spectral distortions
NASA Astrophysics Data System (ADS)
Shiraishi, Maresuke; Liguori, Michele; Bartolo, Nicola; Matarrese, Sabino
2015-10-01
We show that inflationary models with broken rotational invariance generate testable off-diagonal signatures in the correlation between the μ -type distortion and temperature fluctuations of the cosmic microwave background. More precisely, scenarios with a quadrupolar bispectrum asymmetry, usually generated by fluctuations of primordial vector fields, produce a nonvanishing μ -T correlation when |ℓ1-ℓ2|=2 . Since spectral distortions are sensitive to primordial fluctuations up to very small scales, a cosmic variance limited spectral distortion experiment can detect such effects with a high signal-to-noise ratio.
NASA Astrophysics Data System (ADS)
Batle, J.; Ooi, C. H. Raymond; Abdalla, S.
2015-12-01
The purity entanglement measure introduced by Los Alamos group a decade ago is reexamined in the light of interesting features. The role played by purity, reaching a real thermodynamic limit, in detecting quantum phase transitions is studied with a different system, the bond-alternating X Y model in an external magnetic field. The properties of this system are described as well. By considering the dynamics of the original X Y model, we observe that nonergodicity is also grasped by the purity measure, in accordance with other quantum correlation measures that have no common physical or mathematical relation. Adiabaticity is not recovered from the dynamic to the static case, in accordance with one of the consequences of the celebrated Kibble-Zurek mechanism.
Schenk, Gundolf; Krajina, Brad; Spakowitz, Andrew; Doniach, Sebastian
2016-01-01
In vivo chromosomal behavior is dictated by the organization of genomic DNA at length scales ranging from nanometers to microns. At these disparate scales, the DNA conformation is influenced by a range of proteins that package, twist and disentangle the DNA double helix, leading to a complex hierarchical structure that remains undetermined. Thus, there is a critical need for methods of structural characterization of DNA that can accommodate complex environmental conditions over biologically relevant length scales. Based on multiscale molecular simulations, we report on the possibility of measuring supercoiling in complex environments using angular correlations of scattered X-rays resulting from X-ray free electron laser (xFEL) experiments. We recently demonstrated the observation of structural detail for solutions of randomly oriented metallic nanoparticles [D. Mendez et al., Philos. Trans. R. Soc. B 360 (2014) 20130315]. Here, we argue, based on simulations, that correlated X-ray scattering (CXS) has the potential for measuring the distribution of DNA folds in complex environments, on the scale of a few persistence lengths.
Benefits of Time Correlation Measurements for Passive Screening
NASA Astrophysics Data System (ADS)
Murer, David; Blackie, Douglas; Peerani, Paolo
2014-02-01
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, γ) 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.
Atmospheric pollution measurement by optical cross correlation methods - A concept
NASA Technical Reports Server (NTRS)
Fisher, M. J.; Krause, F. R.
1971-01-01
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.
Code of Federal Regulations, 2014 CFR
2014-04-01
... 23 Highways 1 2014-04-01 2014-04-01 false Devices That Are Excluded From Measurement of the Length or Width of a Commercial Motor Vehicle D Appendix D to Part 658 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS TRUCK SIZE AND WEIGHT, ROUTE DESIGNATIONS-LENGTH, WIDTH AND WEIGHT...
The Internal Structure and Correlates of Some School Climate Measures.
ERIC Educational Resources Information Center
Gottfredson, Gary D.
J. M. Richards (1989) has demonstrated that when individuals' reports about environments are aggregated to create environmental measures, the use of coefficient alpha to estimate single occasion reliability can be misleadingly elevated and that alpha cannot distinguish an environmental measure from a "disguised measure of individual differences."…
Choi, Yoonseuk; Rosenblatt, Charles
2010-05-01
A herringbone "easy axis" pattern is scribed into a polyimide alignment layer for liquid-crystal orientation using the stylus of an atomic force microscope. Owing to the liquid crystal's bend elasticity K33 , the nematic director is unable to follow the sharp turn in the scribed easy axis, but instead relaxes over an extrapolation length L=K33/W2φ, where W2φ is the quadratic azimuthal anchoring strength coefficient. By immersing a tapered optical fiber into the liquid crystal, illuminating the fiber with polarized light, and scanning the fiber close to the substrate, a visualization and direct measurement of L are obtained on approaching the nematic-smectic- A phase transition temperature T NA from above. L is found to exhibit a sharp pretransitional increase near T NA, consistent with a diverging bend elastic constant. PMID:20866248
Canudas-Romo, Vladimir; Guillot, Michel
2015-01-01
Period life expectancies are commonly used to compare populations, but these correspond to simple juxtapositions of current mortality levels. In order to construct life expectancies for cohorts, a complete historical series of mortality rates is needed, and these are available for only a subset of developed countries. The truncated cross-sectional average length of life (TCAL) is a new measure that captures historical information about all cohorts present at a given moment and is not limited to countries with complete cohort mortality data. The value of TCAL depends on the rates used to complete the cohort series, but differences between TCALs of two populations remain similar irrespective of the data used to complete the cohort series. This result is illustrated by a comparison of TCALs for the US with those for Denmark, Japan, and other high-longevity countries. Specific cohorts that account for most of the disparity in mortality between the populations are identified. PMID:25871610
Barry, Edward; Dogic, Zvonimir; Meyer, Robert B; Pelcovits, Robert A; Oldenbourg, Rudolf
2009-03-26
In the 1970s, deGennes discussed the fundamental geometry of smectic liquid crystals and established an analogy between the smectic A phase and superconductors. It follows that smectic layers expel twist deformations in the same way that superconductors expel magnetic field. We make a direct observation of the penetration of twist at the edge of a single isolated smectic A layer composed of chiral fd virus particles subjected to a depletion interaction. Using the LC-PolScope, we make quantitative measurements of the spatial dependence of the birefringence due to molecular tilt near the layer edges. We match data to theory for the molecular tilt penetration profile and determine the twist penetration length for this system. PMID:18975886
Barrôco, Rui; Nery, Caio; Favero, Gabriela; Mombach, Renan; Nascimento, Oswaldo; Jorge, Silvia; Monteiro, Marina; Diedrichs, Letícia; Abreu, Felipe
2015-01-01
To identify the mean normal length of the metatarsals and the most common metatarsal formulas through a simple measurement method, thereby providing surgeons with data for planning treatment on symptomatic individuals with biometric abnormalities of the foot. Methods: We evaluated and measured dorsoplantar weight-bearing radiographs of normal adult feet (83 males and 83 females). Results: We found relative mean lengths for metatarsus I of 125.4 mm for males and 115.1 mm for females; for metatarsus II, 127.8 mm for males and 117.3 mm for females; for metatarsus III, 123.4 mm for males and 113.5 mm for females; for metatarsus IV, 114.2 mm for males and 105.3 mm for females; for metatarsus V, 99.5 mm for males and 91.7 mm for females. The mean forefoot width was 87.1 mm for males and 80.8 mm for females. Conclusion: Feet with index minus occurred most frequently in both sexes, although all three metatarsal formulas can be considered to be normal patterns. The mean normal pattern for males and females respectively was the following: metatarsus I 2.4 mm and 2.2 mm shorter than metatarsus II; metatarsus III 4.4 mm and 3.8 mm shorter than metatarsus II; metatarsus IV 9.2 mm and 8.2 mm shorter than metatarsus III; metatarsus V 14.7 mm and 13.6 mm shorter than metatarsus IV. PMID:27027034
Eaton, Mitchell J.; Link, William A.
2011-01-01
Estimating the age of individuals in wild populations can be of fundamental importance for answering ecological questions, modeling population demographics, and managing exploited or threatened species. Significant effort has been devoted to determining age through the use of growth annuli, secondary physical characteristics related to age, and growth models. Many species, however, either do not exhibit physical characteristics useful for independent age validation or are too rare to justify sacrificing a large number of individuals to establish the relationship between size and age. Length-at-age models are well represented in the fisheries and other wildlife management literature. Many of these models overlook variation in growth rates of individuals and consider growth parameters as population parameters. More recent models have taken advantage of hierarchical structuring of parameters and Bayesian inference methods to allow for variation among individuals as functions of environmental covariates or individual-specific random effects. Here, we describe hierarchical models in which growth curves vary as individual-specific stochastic processes, and we show how these models can be fit using capture–recapture data for animals of unknown age along with data for animals of known age. We combine these independent data sources in a Bayesian analysis, distinguishing natural variation (among and within individuals) from measurement error. We illustrate using data for African dwarf crocodiles, comparing von Bertalanffy and logistic growth models. The analysis provides the means of predicting crocodile age, given a single measurement of head length. The von Bertalanffy was much better supported than the logistic growth model and predicted that dwarf crocodiles grow from 19.4 cm total length at birth to 32.9 cm in the first year and 45.3 cm by the end of their second year. Based on the minimum size of females observed with hatchlings, reproductive maturity was estimated to be at nine years. These size benchmarks are believed to represent thresholds for important demographic parameters; improved estimates of age, therefore, will increase the precision of population projection models. The modeling approach that we present can be applied to other species and offers significant advantages when multiple sources of data are available and traditional aging techniques are not practical.
Eaton, M.J.; Link, W.A.
2011-01-01
Estimating the age of individuals in wild populations can be of fundamental importance for answering ecological questions, modeling population demographics, and managing exploited or threatened species. Significant effort has been devoted to determining age through the use of growth annuli, secondary physical characteristics related to age, and growth models. Many species, however, either do not exhibit physical characteristics useful for independent age validation or are too rare to justify sacrificing a large number of individuals to establish the relationship between size and age. Length-at-age models are well represented in the fisheries and other wildlife management literature. Many of these models overlook variation in growth rates of individuals and consider growth parameters as population parameters. More recent models have taken advantage of hierarchical structuring of parameters and Bayesian inference methods to allow for variation among individuals as functions of environmental covariates or individual-specific random effects. Here, we describe hierarchical models in which growth curves vary as individual-specific stochastic processes, and we show how these models can be fit using capture-recapture data for animals of unknown age along with data for animals of known age. We combine these independent data sources in a Bayesian analysis, distinguishing natural variation (among and within individuals) from measurement error. We illustrate using data for African dwarf crocodiles, comparing von Bertalanffy and logistic growth models. The analysis provides the means of predicting crocodile age, given a single measurement of head length. The von Bertalanffy was much better supported than the logistic growth model and predicted that dwarf crocodiles grow from 19.4 cm total length at birth to 32.9 cm in the first year and 45.3 cm by the end of their second year. Based on the minimum size of females observed with hatchlings, reproductive maturity was estimated to be at nine years. These size benchmarks are believed to represent thresholds for important demographic parameters; improved estimates of age, therefore, will increase the precision of population projection models. The modeling approach that we present can be applied to other species and offers significant advantages when multiple sources of data are available and traditional aging techniques are not practical. ?? 2011 by the Ecological Society of America.
Muralikrishnan, B.; Blackburn, C.; Sawyer, D.; Phillips, S.; Bridges, R.
2010-01-01
We describe a method to estimate the scale errors in the horizontal angle encoder of a laser tracker in this paper. The method does not require expensive instrumentation such as a rotary stage or even a calibrated artifact. An uncalibrated but stable length is realized between two targets mounted on stands that are at tracker height. The tracker measures the distance between these two targets from different azimuthal positions (say, in intervals of 20° over 360°). Each target is measured in both front face and back face. Low order harmonic scale errors can be estimated from this data and may then be used to correct the encoder’s error map to improve the tracker’s angle measurement accuracy. We have demonstrated this for the second order harmonic in this paper. It is important to compensate for even order harmonics as their influence cannot be removed by averaging front face and back face measurements whereas odd orders can be removed by averaging. We tested six trackers from three different manufacturers. Two of those trackers are newer models introduced at the time of writing of this paper. For older trackers from two manufacturers, the length errors in a 7.75 m horizontal length placed 7 m away from a tracker were of the order of ± 65 μm before correcting the error map. They reduced to less than ± 25 μm after correcting the error map for second order scale errors. Newer trackers from the same manufacturers did not show this error. An older tracker from a third manufacturer also did not show this error.
Reduction of Gun Erosion and Correlation of Gun Erosion Measurements
NASA Technical Reports Server (NTRS)
Bogdanoff, Dave; Wercinski, Paul (Technical Monitor)
1997-01-01
Gun barrel erosion is serious problem with two-stage light gas guns. Excessive barrel erosion can lead to poor or failed launches and frequent barrel changes, with the corresponding down time. Also, excessive barrel erosion can limit the maximum velocity obtainable by loading down the hydrogen working gas with eroded barrel material. Guided by a CFD code, the operating conditions of the Ames 0.5-inch gun were modified to reduce barrel erosion. The changes implemented included: (1) reduction in the piston mass, powder mass and hydrogen fill pressure; and (2) reduction in pump tube volume, while maintaining hydrogen mass. The latter change was found, in particular, to greatly reduce barrel erosion. For muzzle velocity ranges of 6.1 - 6.9 km/sec, the barrel erosion was reduced by a factor of 10. Even for the higher muzzle velocity range of 7.0 - 8.2 km/sec, the barrel erosion was reduced by a factor of 4. Gun erosion data from the Ames 0.5-inch, 1.0-inch, and 1.5-inch guns operated over a wide variety of launch conditions was examined and it was found that this data could be correlated using four different parameters: normalized powder charge energy, normalized hydrogen energy density, normalized pump tube volume and barrel diameter. The development of the correlation and the steps used to collapse the experimental data are presented. Over a certain parameter range in the correlation developed, the barrel erosion per shot is found to increase very rapidly. The correlation should prove useful in the selection of gun operating conditions and the design of new guns. Representative shapes of eroded gun barrels are also presented.
Williams, Kiel; /SLAC
2012-09-07
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.
Optical fiber measurement techniques based on complementary correlation codes
NASA Astrophysics Data System (ADS)
Fang, Tao; Wen, Ke; Wang, Rong; Xu, Zhi-Yong
2001-10-01
Now, single-mode optical fiber has been widely applied in communication systems and the users of optical fiber have migrated to longer transmission wavelengths, which results in the task of optical fiber measurement becoming more difficult. A method measuring optical fiber properties such as fiber loss and attenuation is optical time domain reflectometer (OTDR) measurement. Conventional OTDRs have a limitation: the trade-off between signal-to-noise ratio and response resolution. This paper presents an approach that applies spectrum-spread techniques to remedy this limitation, and improves dynamic range and reduces measurement time without sacrificing response resolution.
Resolving Dynamics Structure in the Mlt: Correlative Measurements with Tidi and Hrdi
NASA Astrophysics Data System (ADS)
Niciejewski, R.; Skinner, W. R.; Marshall, A.; Cooper, M.
2011-12-01
Undoubtedly, line of sight Doppler measurements of the terrestrial limb have and continue to provide the longest sequence of routine synoptic wind data of the mesosphere and lower thermosphere. To provide the community with basic information about global MLT winds, UARS/HRDI was launched in 1991 and later joined by TIMED/TIDI in 2001. Correlative observations of the MLT with the two instruments began in February 2002 and continued until April 2005 when battery problems aboard UARS forced the final turn-off of HRDI. TIDI continues observing the MLT to the present day with nearly a 100% duty cycle. On short time intervals (a few days), tidal frequencies are difficult to unambiguously identify from orbit by either HRDI or TIDI due to aliasing issues with single satellite observations. Combining measurements from the two platforms provides a significant improvement in understanding two-dimensional frequency wavenumber spectra for short data sets. This paper will describe the progress that has been made in characterizing migrating and non-migrating diurnal tides in the MLT. Short data sets of several days' length are necessary to identify planetary waves, such as the two-day wave, and its effect on MLT dynamics. These waves can transport water vapour exhaust from rocket launches over large distances providing a seed for enhancing noctilucent cloud formation at high latitudes.
Accuracy and precision in camera-based fluorescence correlation spectroscopy measurements.
Sankaran, Jagadish; Bag, Nirmalya; Kraut, Rachel Susan; Wohland, Thorsten
2013-04-16
Imaging fluorescence correlation spectroscopy (FCS) performed using array detectors has been successfully used to quantify the number, mobility, and organization of biomolecules in cells and organisms. However, there have not been any systematic studies on the errors in these estimates that are introduced due to instrumental and experimental factors. State-of-the-art array detectors are still restricted in the number of frames that can be recorded per unit time, sensitivity and noise characteristics, and the total number of frames that can be realistically recorded. These limitations place constraints on the time resolution, the signal-to-noise ratio, and the total measurement time, respectively. This work addresses these problems by using a combination of simulations and experiments on lipid bilayers to provide characteristic performance parameters and guidelines that govern accuracy and precision of diffusion coefficient and concentration measurements in camera-based FCS. We then proceed to demonstrate the effects of these parameters on the capability of camera-based FCS to determine membrane heterogeneity via the FCS diffusion laws, showing that there is a lower length scale limit beyond which membrane organization cannot be detected and which can be overcome by choosing suitable experimental parameters. On the basis of these results, we provide guidelines for an efficient experimental design for camera-based FCS to extract information on mobility, concentration, and heterogeneity. PMID:23521662
Accounting for Correlations across Measures of Perspective Taking.
ERIC Educational Resources Information Center
Rose, Samuel P.
This study examined the development of cognitive perspective taking skills and the lack of consistency across perspective taking measures in earlier studies. Four perspective taking measures were administered to 56 children between 4 and 10 years of age under two testing conditions. The high structure condition included multiple presentation of…
Correlation measurements of light transmittance in polymer dispersed liquid crystals
NASA Astrophysics Data System (ADS)
Maksimyak, P. P.; Nehrych, A. L.
2015-11-01
The methods of correlation optics are for the first time applied to study structure of liquid crystal (LC) - polymer (P) composites at various concentrations of LC and P. Their phase correlation function (PCF) was obtained considering LC-P composite as a random phase screen. The amplitude of PCF contains information about number of LC domains and structure of LC director inside of them, while a half-width of this function is connected with a size of these domains. We studied unpowered and powered composite layers with a thickness of 5 μm. As liquid crystal and polymer were used nematic LC E7 from Merck and photopolymer composition NOA65 from Norland. Concentration of polymer φP was varied in a range 10-55 vol. %. In good agreement with previous studies by SEM technique we detected monotone decrease of LC domains with concentration of polymer. With application of electric field, amplitude of PCF behaves differently for the samples with different polymer content. For the samples with φP>35 vol. % (samples having morphology of polymer dispersed LC), this dependence is monotonic. In turn, if φP<35 vol. % (samples with polymer network LC morphology), the amplitude of PCF non-monotonically depends on the applied voltage going through a maximum. The latter fact is explained by transformation of orientational defects of LC phase with the applied voltage.
NASA Technical Reports Server (NTRS)
Tabib-Azar, Massood
1997-01-01
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.
NASA Astrophysics Data System (ADS)
Loudon, J. C.; Yazdi, S.; Kasama, T.; Zhigadlo, N. D.; Karpinski, J.
2015-02-01
We demonstrate that images of flux vortices in a superconductor taken with a transmission electron microscope can be used to measure the penetration depth and coherence length in all directions at the same temperature and magnetic field. This is particularly useful for MgB 2, where these quantities vary with the applied magnetic field and values are difficult to obtain at low field or in the c direction. We obtained images of flux vortices from a MgB 2 single crystal cut in the a c plane by focused ion beam milling and tilted to 45? with respect to the electron beam about the crystallographic a axis. A new method was developed to simulate these images that accounted for vortices with a nonzero core in a thin, anisotropic superconductor and a simplex algorithm was used to make a quantitative comparison between the images and simulations to measure the penetration depths and coherence lengths. This gave penetration depths ?a b=100 35 nm and ?c=120 15 nm at 10.8 K in a field of 4.8 mT. The large error in ?a b is a consequence of tilting the sample about a and had it been tilted about c , the errors on ?a b and ?c would be reversed. Thus obtaining the most precise values requires taking images of the flux lattice with the sample tilted in more than one direction. In a previous paper [J. C. Loudon et al., Phys. Rev. B 87, 144515 (2013), 10.1103/PhysRevB.87.144515], we obtained a more precise value for ?a b using a sample cut in the a b plane. Using this value gives ?a b=107 8 nm, ?c=120 15 nm, ?a b=39 11 nm, and ?c=35 10 nm, which agree well with measurements made using other techniques. The experiment required two days to conduct and does not require large-scale facilities. It was performed on a very small sample, 30 15 ? m and 200-nm thick, so this method could prove useful for superconductors where only small single crystals are available, as is the case for some iron-based superconductors.
Sampl, Sandra; Pramhas, Sibylle; Stern, Christian; Preusser, Matthias; Marosi, Christine; Holzmann, Klaus
2012-01-01
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
NASA Astrophysics Data System (ADS)
Ullmann, V.; Emam, S.; Manske, E.
2015-08-01
For absolute length and form measurements at a large working distance (>150 mm) two special interferometers, a tandem interferometer and a Michelson interferometer with achromatic polarizing optics are constructed. In our experiments, both consist of a combination of one low-coherence interferometer and one laser interferometer. For the low-coherence interferometer part, a simple white-light source with less than 100 µW optical power output is chosen. It bases upon a low-cost fiber-coupled near-infrared LED with a large spectral width (FWHM > 68 nm at 825 nm). The use of achromatic polarizing optics such as broadband polarizing beamsplitters and achromatic quarter-wave plates in the low-coherence interferometer parts increases the contrast level of the white-light signal fringe pattern to nearly 100%. Furthermore, the fringe pattern in a polarized interferometer has no subsignatures and is unique. Hence, different algorithms are tested for signal processing and automated zero-point detection of the white-light signature. The software for an automated measurement is tested in a standard room without thermal control and without damped oscillation. Therefore, in experiments with the tandem interferometer, it was possible to measure the zero-point position of a white-light signature with a peak-to-peak difference of 154 nm under uncontrolled environmental conditions without thermal stabilization. The white-light Michelson interferometer with polarizing achromatic optics allows zero-point detections with a standard deviation (mean value) of less than 15 nm. The drift is proved through measurement results.
Gilormini, P.; Teyssèdre, H.
2013-01-01
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
NASA Astrophysics Data System (ADS)
Maglich, Bogdan; Radovic, Anna; Druey, Christian
2012-10-01
Genome length, L=, no. of DNA nucleotide base pairs in cell of bovine (b) and porcine (p) tissues, closest to human genome, were hitherto measured by genomic sequencing Lb=3, Lp=2.7 Giga base pairs [1,2] (Gbp) errors not given. - We report measurements of Lb/Lp and Lb, Lp without sequencing by atometry [3,4]. No. of O and C atoms, N, in nucleotide molecules, was obtained from prompt γ rate, G, emitted in inel. scatt. 14 MeV neutrons, with nuclei of C, O, in nucleotide molecule. Since G prop. N, Lb/Lp=Gb/Gp. p and b meat was irradiated for 30'. From msd G we obtained Lb /Lp=1.28±0.02 16% greater than [1,2]. We got absolute Lb=1.65/f, Lp=1.28/f Gbp, 0.3
Role of Weak Measurements on States Ordering and Monogamy of Quantum Correlation
NASA Astrophysics Data System (ADS)
Hu, Ming-Liang; Fan, Heng; Tian, Dong-Ping
2015-01-01
The information-theoretic definition of quantum correlation, e.g., quantum discord, is measurement dependent. By considering the more general quantum measurements, weak measurements, which include the projective measurement as a limiting case, we show that while weak measurements can enable one to capture more quantumness of correlation in a state, it can also induce other counterintuitive quantum effects. Specifically, we show that the general measurements with different strengths can impose different orderings for quantum correlations of some states. It can also modify the monogamous character for certain classes of states as well which may diminish the usefulness of quantum correlation as a resource in some protocols. In this sense, we say that the weak measurements play a dual role in defining quantum correlation.
Collery, Ross F.; Veth, Kerry N.; Dubis, Adam M.; Carroll, Joseph; Link, Brian A.
2014-01-01
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
Snow property measurements correlative to microwave emission at 35 GHz
NASA Technical Reports Server (NTRS)
Davis, Robert E.; Dozier, Jeff; Chang, Alfred T. C.
1987-01-01
Snow microstructure, measured by plane section analysis, and snow wetness, measured by the dilution method, are used to calculate input parameters for a microwave emission model that uses the radiative transfer method. The scattering and absorbing properties are calculated by Mie theory. The effects of different equivalent sphere conversions, adjustments for near-field interference, and different snow wetness characterizations are compared for various snow conditions. The concentric shell geometry of liquid water in snow yields higher emissivities and better model results than the separate-sphere configuration for liquid water contents greater than 0.05, while at lower liquid water contents the separate-sphere treatment gives better results.
Snow property measurements correlative to microwave emission at 35 GHz
NASA Technical Reports Server (NTRS)
Davis, R. E.; Dozier, J.; Chang, A. T. C.
1986-01-01
Snow microstructure, measured by plane section analysis, and snow wetness, measured by the dilution method, are used to calculate input parameters for a microwave emission model that uses the radiative transfer method. The scattering and absorbing properties are calculated by Mie theory. The effects of different equivalent sphere conversions, adjustments for near-field interference, and different snow wetness characterizations are compared for various snow conditions. The concentric shell geometry of liquid water in snow yields higher emissivities and better model results than the separate-sphere configuration for liquid water contents greater than 0.05, while at lower liquid water contents the separate-sphere treatment gives better results.
Endoscopic measurement using radial metrology with digital correlation
NASA Technical Reports Server (NTRS)
Matthys, Donald R.; Gilbert, John A.; Greguss, Pal
1991-01-01
Radial metrology combines standard optical measurement techniques with a unique panoramic annular lens (PAL) system to study material properties and deformations on the inner surfaces of the cavities found, for example, inside pipes, tubes, and boreholes. A PAL profilometer using speckle metrology is analyzed and the equations obtained from the analysis are used to calibrate the PAL profilometer when it is used to profile the inner surface of a cylindrical pipe and to measure the deformation of the pipe when it is subjected to diametral compression.
A Binomial Test of Group Differences with Correlated Outcome Measures
ERIC Educational Resources Information Center
Onwuegbuzie, Anthony J.; Levin, Joel R.; Ferron, John M.
2011-01-01
Building on previous arguments for why educational researchers should not provide effect-size estimates in the face of statistically nonsignificant outcomes (Robinson & Levin, 1997), Onwuegbuzie and Levin (2005) proposed a 3-step statistical approach for assessing group differences when multiple outcome measures are individually analyzed within…
Dimension of quantum phase space measured by photon correlations
NASA Astrophysics Data System (ADS)
Leuchs, Gerd; Glauber, Roy J.; Schleich, Wolfgang P.
2015-06-01
We show that the different values 1, 2 and 3 of the normalized second-order correlation function {g}(2)(0) corresponding to a coherent state, a thermal state and a highly squeezed vacuum originate from the different dimensionality of these states in phase space. In particular, we derive an exact expression for {g}(2)(0) in terms of the ratio of the moments of the classical energy evaluated with the Wigner function of the quantum state of interest and corrections proportional to the reciprocal of powers of the average number of photons. In this way we establish a direct link between {g}(2)(0) and the shape of the state in phase space. Moreover, we illuminate this connection by demonstrating that in the semi-classical limit the familiar photon statistics of a thermal state arise from an area in phase space weighted by a two-dimensional Gaussian, whereas those of a highly squeezed state are governed by a line-integral of a one-dimensional Gaussian. We dedicate this article to Margarita and Vladimir Man’ko on the occasion of their birthdays. The topic of our contribution is deeply rooted in and motivated by their love for non-classical light, quantum mechanical phase space distribution functions and orthogonal polynomials. Indeed, through their articles, talks and most importantly by many stimulating discussions and intensive collaborations with us they have contributed much to our understanding of physics. Happy birthday to you both!
Correlation of subjective and objective measures of speech intelligibility
NASA Astrophysics Data System (ADS)
Bowden, Erica E.; Wang, Lily M.; Palahanska, Milena S.
2003-10-01
Currently there are a number of objective evaluation methods used to quantify the speech intelligibility in a built environment, including the Speech Transmission Index (STI), Rapid Speech Transmission Index (RASTI), Articulation Index (AI), and the Percentage Articulation Loss of Consonants (%ALcons). Many of these have been used for years; however, questions remain about their accuracy in predicting the acoustics of a space. Current widely used software programs can quickly evaluate STI, RASTI, and %ALcons from a measured impulse response. This project compares subjective human performance on modified rhyme and phonetically balanced word tests with objective results calculated from impulse response measurements in four different spaces. The results of these tests aid in understanding performance of various methods of speech intelligibility evaluation. [Work supported by the Univ. of Nebraska Center for Building Integration.] For Speech Communication Best Student Paper Award.
NASA Astrophysics Data System (ADS)
Kino, Shota; Nii, Taiki; Hofmann, Holger F.
2015-10-01
Joint measurements of noncommuting observables are characterized by unavoidable measurement uncertainties that can be described in terms of the error statistics for input states with well-defined values for the target observables. However, a complete characterization of measurement errors must include the correlations between the errors of the two observables. Here, we show that these correlations appear in the experimentally observable measurement statistics obtained by performing the joint measurement on maximally entangled pairs. For two-level systems, the results indicate that quantum theory requires imaginary correlations between the measurement errors of X ̂ and Y ̂ since these correlations are represented by the operator product X ̂Y ̂=i Z ̂ in the measurement operators. Our analysis thus reveals a directly observable consequence of noncommutativity in the statistics of quantum measurements.