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1

The Impact of Outliers on Cronbach's Coefficient Alpha Estimate of Reliability: Visual Analogue Scales  

ERIC Educational Resources Information Center

The impact of outliers on Cronbach's coefficient [alpha] has not been documented in the psychometric or statistical literature. This is an important gap because coefficient [alpha] is the most widely used measurement statistic in all of the social, educational, and health sciences. The impact of outliers on coefficient [alpha] is investigated for…

Liu, Yan; Zumbo, Bruno D.

2007-01-01

2

The Impact of Outliers on Cronbach's Coefficient Alpha Estimate of Reliability: Ordinal/Rating Scale Item Responses  

ERIC Educational Resources Information Center

In a recent Monte Carlo simulation study, Liu and Zumbo showed that outliers can severely inflate the estimates of Cronbach's coefficient alpha for continuous item response data--visual analogue response format. Little, however, is known about the effect of outliers for ordinal item response data--also commonly referred to as Likert, Likert-type,…

Liu, Yan; Wu, Amery D.; Zumbo, Bruno D.

2010-01-01

3

Minimum Sample Size for Cronbach's Coefficient Alpha: A Monte-Carlo Study  

ERIC Educational Resources Information Center

The coefficient alpha is the most widely used measure of internal consistency for composite scores in the educational and psychological studies. However, due to the difficulties of data gathering in psychometric studies, the minimum sample size for the sample coefficient alpha has been frequently debated. There are various suggested minimum sample…

Yurdugul, Halil

2008-01-01

4

Understanding a Widely Misunderstood Statistic: Cronbach's "Alpha"  

ERIC Educational Resources Information Center

It is important to explore score reliability in virtually all studies, because tests are not reliable. The present paper explains the most frequently used reliability estimate, coefficient alpha, so that the coefficient's conceptual underpinnings will be understood. Researchers need to understand score reliability because of the possible impact…

Ritter, Nicola L.

2010-01-01

5

AlphaCI: un programa de cálculo de intervalos de confianza para el coeficiente alfa de Cronbach  

Microsoft Academic Search

Cronbach's alpha coefficient is the most popular way of estimating reliability in measurement scales based on Classic Test Theory. When estimating it, researchers usually omit to report confidence intervals of this coefficient, as it is not only recommended by experts, but also required by some journal's guidelines. This situation is because the different methods of estimating confidence intervals are not

Rubén Ledesma

2004-01-01

6

Statistical Inference for Coefficient Alpha  

Microsoft Academic Search

Rigorous comparison of the reliability coefficients of several tests or measurement procedures requires a sampling theory for the coefficients. This paper sum marizes the important aspects of the sampling theory for Cronbach's (1951) coefficient alpha, a widely used internal consistency coefficient. This theory enables researchers to test a specific numerical hypothesis about the population alpha and to obtain confidence intervals

Leonard S. Feldt; David J. Woodruff; Fathi A. Salih

1987-01-01

7

On the Use, the Misuse, and the Very Limited Usefulness of Cronbach's Alpha  

ERIC Educational Resources Information Center

This discussion paper argues that both the use of Cronbach's alpha as a reliability estimate and as a measure of internal consistency suffer from major problems. First, alpha always has a value, which cannot be equal to the test score's reliability given the inter-item covariance matrix and the usual assumptions about measurement error. Second, in…

Sijtsma, Klaas

2009-01-01

8

Note on Two Generalizations of Coefficient Alpha.  

ERIC Educational Resources Information Center

An important relationship is given for two generalizations of coefficient alpha: (1) Rajaratnam, Cronbach, and Gleser's generalizability formula for stratified-parallel tests, and (2) Raju's coefficient beta. (Author/CTM)

Raju, Nambury S.

1979-01-01

9

Cronbach's [Alpha], Revelle's [Beta], and McDonald's [Omega][sub H]: Their Relations with Each Other and Two Alternative Conceptualizations of Reliability  

ERIC Educational Resources Information Center

We make theoretical comparisons among five coefficients--Cronbach's [alpha], Revelle's [beta], McDonald's [omega][sub h], and two alternative conceptualizations of reliability. Though many end users and psychometricians alike may not distinguish among these five coefficients, we demonstrate formally their nonequivalence. Specifically, whereas…

Zinbarg, Richard E.; Revelle, William; Yovel, Iftah; Li, Wen

2005-01-01

10

Exact distributions of intraclass correlation and Cronbach's alpha with Gaussian data and general covariance  

Microsoft Academic Search

Intraclass correlation and Cronbach's alpha are widely used to describe reliability of tests and measurements. Even with Gaussian\\u000a data, exact distributions are known only for compound symmetric covariance (equal variances and equal correlations). Recently,\\u000a large sample Gaussian approximations were derived for the distribution functions.\\u000a \\u000a New exact results allow calculating the exact distribution function and other properties of intraclass correlation and

Emily O. Kistner; Keith E. Muller

2004-01-01

11

Treating Cronbach's Alpha Reliability Coefficients as Data in Counseling Research  

ERIC Educational Resources Information Center

Scientific associations and measurement experts in psychology and education have voiced various standards and best-practice recommendations concerning reliability data over the years. Yet in the counseling psychology literature, there is virtually no single-source compilation and articulation of good practices for reporting, analyzing, and…

Helms, Janet E.; Henze, Kevin T.; Sass, Terry L.; Mifsud, Venus A.

2006-01-01

12

Factors Affecting Coefficient Alpha: A Mini Monte Carlo Study.  

ERIC Educational Resources Information Center

Factors affecting a lower-bound estimate of internal consistency reliability, Cronbach's coefficient alpha, are explored. Theoretically, coefficient alpha is an estimate of the correlation between two tests drawn at random from a pool of items like the items in the test under consideration. As a practical matter, coefficient alpha can be an index…

Reinhardt, Brian M.

13

What is coefficient alpha? An examination of theory and applications  

Microsoft Academic Search

Coefficient alpha (Cronbach, 1951) is certainly one of the most important and pervasive statistics in research involving test construction and use. A review of the Social Sciences Cita- tions Index for the literature from 1966 to 1990 revealed that Cronbach's (1951) article had been cited approximately 60 times per year and in a total of 278 different journals. In addi-

Jose M. Cortina

1993-01-01

14

My Current Thoughts on Coefficient Alpha and Successor Procedures  

Microsoft Academic Search

In 1997, noting that the 50th anniversary of the publication of “Coefficient Alpha and the Internal Structure of Tests” was fast approaching, Lee Cronbach planned what have become the notes published here. His aimwas to point out theways in which his views on coefficient alpha had evolved, doubting nowthat the coefficientwas the bestway of judging the reliability of an instrument

Lee J. Cronbach; Richard J. Shavelson

2004-01-01

15

Meta-Analysis of Coefficient Alpha  

ERIC Educational Resources Information Center

The meta-analysis of coefficient alpha across many studies is becoming more common in psychology by a methodology labeled reliability generalization. Existing reliability generalization studies have not used the sampling distribution of coefficient alpha for precision weighting and other common meta-analytic procedures. A framework is provided for…

Rodriguez, Michael C.; Maeda, Yukiko

2006-01-01

16

Coefficient Alpha and Reliability of Scale Scores  

ERIC Educational Resources Information Center

The majority of large-scale assessments develop various score scales that are either linear or nonlinear transformations of raw scores for better interpretations and uses of assessment results. The current formula for coefficient alpha (a; the commonly used reliability coefficient) only provides internal consistency reliability estimates of raw…

Almehrizi, Rashid S.

2013-01-01

17

Bayesian Statistical Inference for Coefficient Alpha. ACT Research Report Series.  

ERIC Educational Resources Information Center

Coefficient alpha is a simple and very useful index of test reliability that is widely used in educational and psychological measurement. Classical statistical inference for coefficient alpha is well developed. This paper presents two methods for Bayesian statistical inference for a single sample alpha coefficient. An approximate analytic method…

Li, Jun Corser; Woodruff, David J.

18

A Clarification of the Effects of Rapid Guessing on Coefficient [Alpha]: A Note on Attali's "Reliability of Speeded Number-Right Multiple-Choice Tests"  

ERIC Educational Resources Information Center

Attali (2005) recently demonstrated that Cronbach's coefficient [alpha] estimate of reliability for number-right multiple-choice tests will tend to be deflated by speededness, rather than inflated as is commonly believed and taught. Although the methods, findings, and conclusions of Attali (2005) are correct, his article may inadvertently invite a…

Wise, Steven L.; DeMars, Christine E.

2009-01-01

19

Asymptotically Distribution-Free (ADF) Interval Estimation of Coefficient Alpha  

ERIC Educational Resources Information Center

The point estimate of sample coefficient alpha may provide a misleading impression of the reliability of the test score. Because sample coefficient alpha is consistently biased downward, it is more likely to yield a misleading impression of poor reliability. The magnitude of the bias is greatest precisely when the variability of sample alpha is…

Maydeu-Olivares, Alberto; Coffman, Donna L.; Hartmann, Wolfgang M.

2007-01-01

20

Varying Coefficient Meta-Analytic Methods for Alpha Reliability  

ERIC Educational Resources Information Center

The conventional fixed-effects (FE) and random-effects (RE) confidence intervals that are used to assess the average alpha reliability across multiple studies have serious limitations. The FE method, which is based on a constant coefficient model, assumes equal reliability coefficients across studies and breaks down under minor violations of this…

Bonett, Douglas G.

2010-01-01

21

Correcting Coefficient Alpha for Correlated Errors: Is [alpha][K]a Lower Bound to Reliability?  

ERIC Educational Resources Information Center

When errors of measurement are positively correlated, coefficient alpha may overestimate the "true" reliability of a composite. To reduce this inflation bias, Komaroff (1997) has proposed an adjusted alpha coefficient, ak. This article shows that ak is only guaranteed to be a lower bound to reliability if the latter does not include correlated…

Rae, Gordon

2006-01-01

22

A Note on the Estimator of the Alpha Coefficient for Standardized Variables Under Normality  

ERIC Educational Resources Information Center

The asymptotic standard deviation (SD) of the alpha coefficient with standardized variables is derived under normality. The research shows that the SD of the standardized alpha coefficient becomes smaller as the number of examinees and/or items increase. Furthermore, this research shows that the degree of the dependence of the SD on the number of…

Hayashi, Kentaro; Kamata, Akihito

2005-01-01

23

ScoreRel CI: An Excel Program for Computing Confidence Intervals for Commonly Used Score Reliability Coefficients  

Microsoft Academic Search

An Excel program developed to assist researchers in the determination and presentation of confidence intervals around commonly used score reliability coefficients is described. The software includes programs to determine confidence intervals for Cronbach’s alpha, Pearson r-based coefficients such as those used in test-retest and alternate forms situations, split-half, and Cohen’s 2 × 2 unweighted Kappa. The general basis for the

J. Jackson Barnette

2005-01-01

24

Coefficient alpha and the internal structure of tests  

Microsoft Academic Search

A general formula (?) of which a special case is the Kuder-Richardson coefficient of equivalence is shown to be the mean of\\u000a all split-half coefficients resulting from different splittings of a test. ? is therefore an estimate of the correlation between\\u000a two random samples of items from a universe of items like those in the test. ? is found to

Lee J. Cronbach

1951-01-01

25

Hardy-Littlewood theorem for trigonometric series with {alpha}-monotone coefficients  

SciTech Connect

The Hardy-Littlewood theorem is established for trigonometric series with {alpha}-monotone coefficients. Inequalities of Hardy-Littlewood kind are proved. Examples of series demonstrating that the results obtained are sharp are constructed. Bibliography: 15 titles.

Dyachenko, Mikhail I [M. V. Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow (Russian Federation); Nursultanov, Erlan D [Kazakhstan Branch of Lomonosov Moscow State University, Astana (Kazakhstan)

2009-12-31

26

Improving Construct Validity: Cronbach, Meehl, and Neurath's Ship--Comment  

ERIC Educational Resources Information Center

Smith's article "On Construct Validity: Issues of Method and Measurement" is a fine tribute to L. J. Cronbach and P. E. Meehl (1955) that clarifies the current state and future directions in the understanding of construct validity. Construct validity is a dynamic process, and fit indices need to be used at the service of understanding, not in…

Westen, Drew; Rosenthal, Robert

2005-01-01

27

Coefficient alpha and the reliability of composite measurements  

Microsoft Academic Search

Following a general approach due to Guttman, coefficient is rederived as a lower bound on the reliability of a test. A necessary and sufficient condition under which equality is attained in this inequality and hence that is equal to the reliability of the test is derived and shown to be closely related to the recent redefinition of the concept of

Melvin R. Novick; Charles Lewis

1967-01-01

28

SIMREL: Software for Coefficient Alpha and Its Confidence Intervals with Monte Carlo Studies  

ERIC Educational Resources Information Center

This article describes SIMREL, a software program designed for the simulation of alpha coefficients and the estimation of its confidence intervals. SIMREL runs on two alternatives. In the first one, if SIMREL is run for a single data file, it performs descriptive statistics, principal components analysis, and variance analysis of the item scores…

Yurdugul, Halil

2009-01-01

29

ScoreRel CI: An Excel Program for Computing Confidence Intervals for Commonly Used Score Reliability Coefficients  

ERIC Educational Resources Information Center

An Excel program developed to assist researchers in the determination and presentation of confidence intervals around commonly used score reliability coefficients is described. The software includes programs to determine confidence intervals for Cronbachs alpha, Pearson r-based coefficients such as those used in test-retest and alternate forms…

Barnette, J. Jackson

2005-01-01

30

Octanol-water partition coefficients of substituted alpha, N-diphenylnitrones and benzonitrile N-oxides  

SciTech Connect

Experimental octanol-water partition coefficients are reported for substituted alpha, N-diphenylnitrones and benzonitrile N-oxides. The results of these measurements are used to calculate the aromatic fragment constants pi HC = N(O)C6H5, pi C = N----O, fHC = N(O), and fC = N----O for the group contribution methods of Hansch and Leo.

Kirchner, J.J.; Acree, W.E. Jr.; Leo, A.J.; Gelli, G.

1985-10-01

31

Birefringence and absorption coefficients of alpha barium borate in terahertz range  

NASA Astrophysics Data System (ADS)

In this paper we experimentally investigated the birefringence and absorption coefficients of alpha barium borate (?-BBO) crystal in the range of 0.3-10 THz by using a broadband air photonic terahertz time-domain spectrometer in both transmission and reflection modes. Several phonon modes were observed for o and e beams. The highest phonon mode at 6.8 THz has absorption coefficient of 1000 cm-1. The comparison between the optical properties of the ?-BBO and beta barium borate crystals showed that their phonon frequencies are different and ?-BBO crystal has smaller refractive index, birefringence, and absorption coefficients in low frequency region. The blueshift behavior of the lowest phonon of the ?-BBO crystal over the temperature range of 10-293 K has also been characterized.

Liu, Jingle; Zhang, X. C.

2009-07-01

32

Confidence Intervals For Maximized Alpha Coefficients: An Evaluation of Joe and Woodward's Procedures and an Alternative Method.  

ERIC Educational Resources Information Center

The procedures yielding confidence intervals for maximized alpha coefficients of Joe and Woodward are reviewed. Confidence interval procedures of Whalen and Masson are next reviewed. Results are then presented of a Monte Carlo investigation of the procedures. (Author/CTM)

Hakstian, A. Ralph; And Others

1980-01-01

33

The local skin dose conversion coefficients of electrons, protons and alpha particles calculated using the Geant4 code.  

PubMed

The skin tissue-equivalent slab reported in the International Commission on Radiological Protection (ICRP) Publication 116 to calculate the localised skin dose conversion coefficients (LSDCCs) was adopted into the Monte Carlo transport code Geant4. The Geant4 code was then utilised for computation of LSDCCs due to a circular parallel beam of monoenergetic electrons, protons and alpha particles <10 MeV. The computed LSDCCs for both electrons and alpha particles are found to be in good agreement with the results using the MCNPX code of ICRP 116 data. The present work thus validates the LSDCC values for both electrons and alpha particles using the Geant4 code. PMID:23610196

Zhang, Bintuan; Dang, Bingrong; Wang, Zhuanzi; Wei, Wei; Li, Wenjian

2013-10-01

34

Alpha radiation risk coefficients for liver cancer, bone sarcomas, and leukemia.  

PubMed

This study compares published risk coefficients with those determined from dose rates established by postmortem radiochemical analysis of tissues from two whole body donors to the U. S. Transuranium and Uranium Registries, both of whom had been injected with Thorotrast approximately four decades prior to death. The dose data from these cases were used in combination with published latent periods and epidemiologic study results to calculate the following risk coefficients: 0.020 liver cancers Gy-1, 0.002 bone sarcomas Gy-1, and 0.032 leukemias Gy-1. These compare with the ranges of 0.013 to 0.074 liver cancers Gy-1, 0.0016 to 0.0120 bone sarcomas Gy-1, and 0.005 to 0.060 leukemias Gy-1 reported in the literature. The results of this study are generally consistent with previously reported values with two exceptions: the values for bone sarcomas fall below the range given by BEIR IV and the values for leukemia are a factor of 6 greater than those reported by BEIR IV. This suggests that the BEIR IV risk coefficient for bone sarcomas may be too high, and that for leukemia may be too low. PMID:7989193

Hunacek, M M; Kathren, R L

1995-01-01

35

Comparison of aerodynamic coefficients obtained from theoretical calculations wind tunnel tests and flight tests data reduction for the alpha jet aircraft  

NASA Technical Reports Server (NTRS)

The methods by which aerodynamic coefficients are determined and discussed. These include: calculations, wind tunnel experiments and experiments in flight for various prototypes of the Alpha Jet. A comparison of obtained results shows good correlation between expectations and in-flight test results.

Guiot, R.; Wunnenberg, H.

1980-01-01

36

Alpha Thalassemia  

MedlinePLUS

Alpha Thalassemia ? Physicians often mistake alpha thalassemia trait for iron deficiency anemia and incorrectly prescribe iron supplements that have no effect on the anemia. Normal alpha globin genes ...

37

Coefficient estimates for inverses of starlike functions of positive order  

NASA Astrophysics Data System (ADS)

In the present paper, the coefficient estimates are found for the class consisting of inverses of functions in the class of univalent starlike functions of order [alpha] in . These estimates extend the work of Krzyz, Libera and Zlotkiewicz [J.G. Krzyz, R.J. Libera, E. Zlotkiewicz, Coefficients of inverse of regular starlike functions, Ann. Univ. Mariae Curie-Sklodowska Sect. A 33 (10) (1979) 103-109] who found sharp estimates on only first two coefficients for the functions in the class . The coefficient estimates are also found for the class [Sigma]*-1([alpha]), consisting of inverses of functions in the class [Sigma]*([alpha]) of univalent starlike functions of order [alpha] in . The open problem of finding sharp coefficient estimates for functions in the class [Sigma]*([alpha]) stands completely settled in the present work by our method developed here.

Kapoor, G. P.; Mishra, A. K.

2007-05-01

38

A parametric study of planform and aeroelastic effects on aerodynamic center, alpha- and q- stability derivatives. Appendix C: Method for computing the aerodynamic influence coefficient matrix of nonplanar wing-body-tail configurations  

NASA Technical Reports Server (NTRS)

Expressions are derived for computing the aerodynamic influence coefficient matrix for nonplanar wing-body-tail configurations. An aerodynamic influence coefficient is defined as the load in lbs. induced on a panel as a result of a unit angle of attack on another panel. Fuselage, wing and tail thickness are assumed to be small with the result that the thickness effect on the flow-field is negligible. The method for determining the aerodynamic influence coefficient matrix is based on the lifting solution to the small perturbation, steady potential flow equation.

Roskam, J.

1972-01-01

39

Cross sections and excitation rate coefficients for the 2s{sup 2}2p{sup 5}2P{sub 3/2}-2s{sup 2}2p{sup 5}2P{sub 1/2} transition in fluorine-like ions by p, d, t, and {alpha} impact  

SciTech Connect

Cross sections and rate coefficients for excitation of the 2s{sup 2}2p{sup 5}{sup 2}P{sub 3/2}-2s{sup 2}2p{sup 5}{sup 2}P{sub 1/2} transition in fluorine-like ions by proton, deuteron, triton, and {alpha}-particle impact have been calculated using the close-coupled impact parameter method. The ions considered are Ne II, S VIII, Ti XIV, Ni XX, Zn XXII, Ge XXIV, Se XXVI, Kr XXVIII, Mo XXXIV, Ag XXXIX, and Pb LXXIV. Cross sections were calculated for a range of impact energies, and the 2s2p{sup 6} {sup 2}S state was included by means of a polarization potential. Excitation rate coefficients have been calculated from the cross sections for a wide range of temperatures. 17 refs., 2 tabs.

Foster, V.J.; Keenan, F.P.; Reid, R.H.G. [Queen`s Univ. of Belfast (Ireland)] [Queen`s Univ. of Belfast (Ireland)

1994-11-01

40

Seebeck Coefficient of Semiconducting Oxide Glasses.  

National Technical Information Service (NTIS)

The Seebeck Coefficient, alpha, of semiconducting glasses based on vanadium pentoxide can be calculated from a knowledge of the concentration ratio of the high and low valence ions. The concentration of vanadium ions in the glass and long range order appa...

T. Allersma J. D. Mackenzie

1966-01-01

41

INTERNAL CONVERSION COEFFICIENTS - HOW GOOD ARE THEY NOW?  

SciTech Connect

Internal conversion coefficients involving atomic electrons (ICC) and electron-positron pairs (IPC) are often required to determine transition multipolarities and total transition rates. A new internal conversion coefficient data base, BrIcc has been developed which integrates a number of tabulations on ICC and IPC, as well as {Omega}(E0) electronic factors. To decide which theoretical internal conversion coefficient table to use, the accurately determined experimental {alpha}{sub K}, {alpha}{sub L}, {alpha}{sub Total} and {alpha}{sub K}/{alpha}{sub L} values were compared with the new Dirac-Fock calculations using extreme assumptions on the effect of the atomic vacancy. While the overall difference between experiment and theory is less than 1%, our analysis shows preference towards the so called ''Frozen Orbital'' approximation, which takes into account the effect of the atomic vacancy.

KIBEDI,T.; BURROWS, T.W.; TRZHASKOVSKAYA, M.B.; NESTOR, JR., C.W.; DAVIDSON, P.M.

2007-04-22

42

Prediction of coefficients of thermal expansion for unidirectional composites  

NASA Technical Reports Server (NTRS)

Several analyses for predicting the longitudinal, alpha(1), and transverse, alpha(2), coefficients of thermal expansion of unidirectional composites were compared with each other, and with experimental data on different graphite fiber reinforced resin, metal, and ceramic matrix composites. Analytical and numerical analyses that accurately accounted for Poisson restraining effects in the transverse direction were in consistently better agreement with experimental data for alpha(2), than the less rigorous analyses. All of the analyses predicted similar values of alpha(1), and were in good agreement with the experimental data. A sensitivity analysis was conducted to determine the relative influence of constituent properties on the predicted values of alpha(1), and alpha(2). As would be expected, the prediction of alpha(1) was most sensitive to longitudinal fiber properties and the prediction of alpha(2) was most sensitive to matrix properties.

Bowles, David E.; Tompkins, Stephen S.

1989-01-01

43

Generalized Gaunt coefficients  

Microsoft Academic Search

Solid-harmonic derivatives of solid-harmonic-Gaussian integrals are evaluated. Cross differentiation and the n-j generalized Gaunt coefficients are defined. The generalized Gaunt coefficients ensure that cross differentiation in uncoupled, n-center, solid-harmonic derivatives of rotationally invariant Gaussian matrix elements subtracts zero total angular momentum. This preserves the spherical-tensor properties of quantum-chemical matrix elements. The generalized Gaunt coefficients are (n-1)-dimensional objects because the sum

Brett I. Dunlap

2002-01-01

44

Binomial Coefficient Model  

NSDL National Science Digital Library

The Binomial Coefficient model displays the number of ways k objects can be chosen from among n objects when order is irrelevant.   This number is known as a binomial coefficient and can be used to predict the the flipping of n coins with equal probability of heads and tails. The Binomial Coefficient model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_stp_BinomialCoefficient.jar file will run the program if Java is installed.

Christian, Wolfgang

2010-04-11

45

Coefficient Color Constancy  

NASA Astrophysics Data System (ADS)

The goal of color constancy is to take the color responses (for example camera rgb triplets) of surfaces viewed under nn unknown illuminant and map them to illuminant independent descriptors. In existing theories this mapping is either a general linear 3 times 3 matrix or a simple diagonal matrix of scaling coefficients. The general theories have the advantage that the illuminant can be accurately discounted but have the disadvantage that nine parameters must be recovered. Conversely while the coefficient theories have only three unknowns, a diagonal matrix may only partially discount the illuminant. My starting point in this thesis is to generalize the coefficient approach; the goal is to retain its inherent simplicity while at the same time increasing its expressive power. Under the generalized coefficient scheme, I propose that a visual system transforms responses to a new sensor basis before applying the scaling coefficients. I present methods for choosing the best coefficient basis for a variety of statistical models of color responses. These models are rich enough that the generalized coefficient approach suffices for almost all possible sensor sets. To achieve color constancy the correct coefficients must be recovered. Existing algorithms can do so only when strong constraints are satisfied. For example it is often assumed that there is a white reflectance in every scene. In the second part of any thesis, I develop a new coefficient algorithm, which I call color in perspective, based on very weak (and very reasonable) assumptions about the world. I assume only that the range of color responses induced by different reflectances varies with a change in illumination and that illumination itself can vary only within certain bounds. I tested the algorithm on real images taken with a color video camera--extremely good constancy is delivered. Indeed the degree of constancy compares favorably with the best which is theoretically possible. The methods developed in this thesis can be applied to a variety of other areas: including color graphics, color reproduction and color appearance models.

Finlayson, Graham David

1995-01-01

46

Alpha One Foundation  

MedlinePLUS

English Français ( French ) Deutsch ( German ) Italiano ( Italian ) Español ( Spanish ) Português ( Portuguese ) Svenska ( Swedish ) Alpha-1 Foundation in Google Plus Alpha-1 Foundation in Twitter Alpha-1 Foundation ...

47

Strength Coefficient of Materials.  

National Technical Information Service (NTIS)

South Dakota's, previously conducted, Flexible Pavement Study indicated a relationship between Strength and Effective Thickness. It was apparent that a simple slope formula used for any two points on the curve produced strength coefficients. The slope of ...

R. A. Crawford

1971-01-01

48

Drag Coefficients of Cones.  

National Technical Information Service (NTIS)

The objective was to provide experimental values for cone drag coefficients in the near free molecule and transitional flow regimes including an examination of the effects of Mach number, wall speed ratio, bluntness, and specific heat ratio. A modulated f...

J. F. Wendt

1972-01-01

49

Coefficients of Effective Length.  

ERIC Educational Resources Information Center

Under certain conditions, a validity Coefficient of Effective Length (CEL) can produce highly misleading results. A modified coefficent is suggested for use when empirical studies indicate that underlying assumptions have been violated. (Author/BW)

Edwards, Roger H.

1981-01-01

50

Coefficients Alpha, Beta, Omega, and the glb: Comments on Sijtsma  

ERIC Educational Resources Information Center

There are three fundamental problems in Sijtsma ("Psychometrika," 2008): (1) contrary to the name, the glb is not the greatest lower bound of reliability but rather is systematically less than omega[subscript t] (McDonald, "Test theory: A unified treatment," Erlbaum, Hillsdale, 1999), (2) we agree with Sijtsma that when considering how well a test…

Revelle, William; Zinbarg, Richard E.

2009-01-01

51

Alpha Thalassemia (For Parents)  

MedlinePLUS

... it results in that type of thalassemia. About Alpha Thalassemia Alpha thalassemia occurs when the gene that ... transport oxygen around the body. Continue Types of Alpha Thalassemia Alpha globin is made by four genes ...

52

Pearson's Correlation Coefficient  

NSDL National Science Digital Library

This tutorial on Pearson's Correlation Coefficient includes the definition, assumptions, and characteristics of r as well as related statistics and hypothesis test procedures. One section instructs users to find correlation in the WINKS software, but those without the software can still use the tutorial. An exercise is given at the end that can be done with any statistical software package.

2009-01-09

53

Point Biserial Correlation Coefficient  

NSDL National Science Digital Library

This page calculates the point biserial correlation coefficient for the case where one variable is dichotomous and the other is non-dichotomous. This page allows the user to input the data directly or copy and paste from a spreadsheet application and provides data summary.

Lowry, Richard, 1940-

2008-06-26

54

Predicting protein diffusion coefficients.  

PubMed Central

Diffusion coefficients for proteins in water are predicted. The numerical method developed is general enough to be applied to a wide range of protein surface shapes, from rodlike to globular. Results are presented for lysozyme and tobacco mosaic virus, and they are compared with actual data and with predictions made by less general methods. Images Fig. 2

Brune, D; Kim, S

1993-01-01

55

Metastable ion study of fluorinated organic compounds. Part 3. [alpha], [alpha], [alpha]-trifluoroanisole and [alpha], [alpha], [alpha]-trifluorocresols  

NASA Astrophysics Data System (ADS)

The spontaneous unimolecular dissociation reactions of the molecular ions of the C7H5F3O positional isomers [alpha], [alpha], [alpha]-trifluoroanisole (1), o-[alpha], [alpha], [alpha],-trifluorocresol (2) and m-[alpha], [alpha], [alpha]-trilfluorocresol (3), have been investigated by mass-analyzed ion kinetic energy (MIKE) spectrometry and deuterium-labellin. The results are compared with those of the non-fluorinated analogues anisole (4), o-cresol (5) and m-cresol (6). Ions 1.+ and 4.+ fragment in an analogue fashion yielding MIKE spectra which are characteristically different from those isaomers of the isomers 2.+, 3.+, 5.+ and 6.+ whose MIKE spectra are closely similar, the fluorinated analogues 2.+ and 2.+ have different characteristics. This is because a pronounced ortho-effect is operative in 2.+.

Yanagisawa, Tamae; Tajima, Susumu; Iizuka, Masaki; Tobita, Seiji; Mitani, Motohiro; Matsumoto, Takeo

1993-05-01

56

A Novel Approach for Optimal Location and Sizing of Capacitors on Radial Distribution Systems Using Loss Sensitivity Factors and ?- Coefficients  

Microsoft Academic Search

This paper presents a novel approach that determines the optimal location and size of capacitors on radial distribution systems to improve voltage profile and reduce the active power loss. Capacitor placement & sizing are done by loss sensitivity factors and alpha-coefficients respectively. The concept of loss sensitivity factors and alpha-coefficients can be considered as the new contribution in the area

K. Prakash; M. Sydulu

2006-01-01

57

Prediction of Aerodynamic Coefficients using Neural Networks for Sparse Data  

NASA Technical Reports Server (NTRS)

Basic aerodynamic coefficients are modeled as functions of angles of attack and sideslip with vehicle lateral symmetry and compressibility effects. Most of the aerodynamic parameters can be well-fitted using polynomial functions. In this paper a fast, reliable way of predicting aerodynamic coefficients is produced using a neural network. The training data for the neural network is derived from wind tunnel test and numerical simulations. The coefficients of lift, drag, pitching moment are expressed as a function of alpha (angle of attack) and Mach number. The results produced from preliminary neural network analysis are very good.

Rajkumar, T.; Bardina, Jorge; Clancy, Daniel (Technical Monitor)

2002-01-01

58

From alpha to omega: A practical solution to the pervasive problem of internal consistency estimation.  

PubMed

Coefficient alpha is the most popular measure of reliability (and certainly of internal consistency reliability) reported in psychological research. This is noteworthy given the numerous deficiencies of coefficient alpha documented in the psychometric literature. This mismatch between theory and practice appears to arise partly because users of psychological scales are unfamiliar with the psychometric literature on coefficient alpha and partly because alternatives to alpha are not widely known. We present a brief review of the psychometric literature on coefficient alpha, followed by a practical alternative in the form of coefficient omega. To facilitate the shift from alpha to omega, we also present a brief guide to the calculation of point and interval estimates of omega using a free, open source software environment. PMID:24844115

Dunn, Thomas J; Baguley, Thom; Brunsden, Vivienne

2014-08-01

59

Alpha One Foundation  

MedlinePLUS

What is Alpha-1? A lpha-1 Antitrypsin Deficiency (Alpha-1) is a genetic (inherited) condition – it is passed from parents to their children through their genes. Alpha-1 may result in serious lung disease in ...

60

LETTER TO THE EDITOR: Determination of the critical exponent of the linear thermal expansion coefficient of nickel by neutron diffraction  

Microsoft Academic Search

The linear thermal expansion coefficient alpha has been measured on a nickel single crystal with a high-resolution neutron back-scattering diffractometer near the magnetic phase transition. From alpha , the critical part of the thermal expansion coefficient alpha c was separated and fitted to a power-law equation within the reduced temperature range t= mod (T-TC)\\/TC mod =10-2 to 10-3. The critical

T. A. Faisst

1989-01-01

61

The Transport Coefficients  

NASA Astrophysics Data System (ADS)

In this section we wish to give a detailed account of all the transport coefficients related to the vectorial fluxes discussed in the previous chapters. These are the mass flux Ja (=-Jb ), the corresponding charge flux or electrical current Jc , closely related to Ja , and J^'q the heat flux. In every case the magnetic field is chosen as the direction of the z-axis, B=Bhat{k} so that for any vector, its different components respect to B will follow from the decomposition illustrated in Fig. (4.1).

García-Colín, Leopoldo S.; Dagdug, Leonardo

62

Statistical Considerations in Choosing a Test Reliability Coefficient. ACT Research Report Series, 2012 (10)  

ERIC Educational Resources Information Center

The purpose of this paper is to illustrate alpha's robustness and usefulness, using actual and simulated educational test data. The sampling properties of alpha are compared with the sampling properties of several other reliability coefficients: Guttman's lambda[subscript 2], lambda[subscript 4], and lambda[subscript 6]; test-retest reliability;…

Woodruff, David; Wu, Yi-Fang

2012-01-01

63

The Dependence Structure for PARMA Models with alpha -Stable Innovations  

NASA Astrophysics Data System (ADS)

In this paper we investigate the dependence structure for PARMA models (i.e. ARMA models with periodic coefficients) with symmetric alpha -stable innovations. In this case the covariance function is not defined and therefore other measures of dependence have to be used. After obtaining the form of the bounded solution of the PARMA system with symmetric alpha -stable innovations, we study the codifference and the covariation -- the most popular measures of dependence defined for symmetric stable time series. We show that both considered measures are periodic. Moreover we determine the cases when the codifference and the covariation are asymptotically proportional with the coefficient of proportionality equal to alpha .

Nowicka-Zagrajek, J.; Wylomanska, A.

2006-11-01

64

Recursive calculation of hansen coefficients  

Microsoft Academic Search

Hansen coefficients are used in expansions of the elliptic motion. Three methods for calculating the coefficients are studied: Tisserand's method, the Von Zeipel-Andoyer (VZA) method with explicit representation of the polynomials required to compute the Hansen coefficients, and the VZA method with the values of the polynomials calculated recursively. The VZA method with explicit polynomials is by far the most

Richard L. Branham

1990-01-01

65

Effective inertial coefficient for the dinuclear regime of the exotic decay of nuclei  

Microsoft Academic Search

Geometric and incompressibility constraint relations are used explicitly in reducing the number of collective variables of the dinuclear phase of the fissioning system to calculate the barrier penetrability factor. Consistently, we define an effective inertial coefficient for the relative motion of the fissioning system. With this inertial coefficient, half-lives of the exotic and alpha decays are successfully reproduced for all

S. B. Duarte; M. G. Goncalves

1996-01-01

66

On Robustness of the Normal-Theory Based Asymptotic Distributions of Three Reliability Coefficient Estimates.  

ERIC Educational Resources Information Center

Examined the asymptotic distributions of three reliability coefficient estimates: (1) sample coefficient alpha; (2) reliability estimate of a composite score following factor analysis; and (3) maximal reliability of a linear combination of item scores after factor analysis. Findings show that normal theory based asymptotic distributions for these…

Yuan, Ke-Hai; Bentler, Peter M.

2002-01-01

67

Phenyl-/alpha/,/alpha/,/omega/-trihydropolyfluoroalkyliodonium fluoroborates  

SciTech Connect

The reaction of difluoroiodo-/alpha/,/alpha/,/omega/-trihydrofluoroalkanes (I) with boron trifluoride and benzene gave phenyl-/alpha/,/alpha/,/omega/-trihydropolyfluoroalkyliodonium fluoroborates (II). It was established that the polyfluoroalkyl radical adds at the sulfur atom in reaction with p-chlorothiophenol, the N-polyfluoroalkylation product is formed with aniline, pyridine is polyfluoroalkylated at the nitrogen atom with the formation of a quaternary salt, and a mixture of products from polyfluoroalkylation at the nitrogen atom of the dimethylamino group and at the para position of the benzene ring is formed with dimethylaniline.

Mironova, A.A.; Soloshonok, I.V.; Maletina, I.I.; Orda, V.V.; Yagupol'skii, L.M.

1988-08-20

68

Antibody biodistribution coefficients  

PubMed Central

Tissue vs. plasma concentration profiles have been generated from a physiologically-based pharmacokinetic model of monoclonal antibody (mAb). Based on the profiles, we hypothesized that a linear relationship between the plasma and tissue concentrations of non-binding mAbs could exist; and that the relationship may be generally constant irrespective of the absolute mAb concentration, time, and animal species being analyzed. The hypothesis was verified for various tissues in mice, rat, monkey, and human using mAb or antibody-drug conjugate tissue distribution data collected from diverse literature. The relationship between the plasma and various tissue concentrations was mathematically characterized using the antibody biodistribution coefficient (ABC). Estimated ABC values suggest that typically the concentration of mAb in lung is 14.9%, heart 10.2%, kidney 13.7%, muscle 3.97%, skin 15.7%, small intestine 5.22%, large intestine 5.03%, spleen 12.8%, liver 12.1%, bone 7.27%, stomach 4.98%, lymph node 8.46%, adipose 4.78%, brain 0.351%, pancreas 6.4%, testes 5.88%, thyroid 67.5% and thymus is 6.62% of the plasma concentration. The validity of using the ABC to predict mAb concentrations in different tissues of mouse, rat, monkey, and human species was evaluated by generating validation data sets, which demonstrated that predicted concentrations were within 2-fold of the observed concentrations. The use of ABC to infer tissue concentrations of mAbs and related molecules provides a valuable tool for investigating preclinical or clinical disposition of these molecules. It can also help eliminate or optimize biodistribution studies, and interpret efficacy or toxicity of the drug in a particular tissue.

Shah, Dhaval K.; Betts, Alison M.

2013-01-01

69

Reaction and Anomalous Transport: Effective Reaction Rate Coefficients from the Multirate Model  

NASA Astrophysics Data System (ADS)

One cause of anomalous transport is a distribution of exchange rates between fast- and slow-moving water. Slow-moving water is frequently the preferred location of the most significant reactions, such as in biofilms. We express transport and reaction using the multirate model and we assume first-order reaction from parent to daughter. In this case, the effective rate coefficient can be expressed ? _a = int_0^{infty } frac{alpha p(alpha) ? }{alpha +? } dalpha where alpha is the mass transfer rate coefficient, ?mda is the reaction rate coefficient, and p(alpha) is the density function of mass transfer rate coefficients in the multirate model. Exchange rates much slower than ?mda contribute relatively little to the effective rate coefficient, while exchange rates similar to or faster than ?mda contribute most to the effective rate coefficient. Consequently, a conservative solute may experience anomalous transport, but a reacting solute may exhibit behavior that is not significantly different from Fickian transport with reaction.

Haggerty, R.

2012-12-01

70

Table for determining phi coefficients  

Microsoft Academic Search

A table is presented which directly gives phi coefficients accurate to three places when entered by the proportion of one sub-group responding in a specified manner and the proportion of a second sub-group responding in the same manner. The table gives coefficients identical with those obtained by formula if the sub-groups are equal in number. The phi coefficients can readily

C. E. Jurgensen

1947-01-01

71

STP Second Virial Coefficient Program  

NSDL National Science Digital Library

The STP SecondVirialCoefficient program numerically evaluates the second virial coefficient for the Lennard-Jones potential at various temperatures. The default is temperature range is 0.5 to 5. STP SecondVirialCoefficient is part of a suite of Open Source Physics programs that model aspects of Statistical and Thermal Physics (STP). The program is distributed as a ready-to-run (compiled) Java archive. Double clicking the stp_SecondVirialCoefficient.jar file will run the program if Java is installed on your computer. Additional programs can be found by searching ComPADRE for Open Source Physics, STP, or Statistical and Thermal Physics.

Gould, Harvey; Tobochnik, Jan; Christian, Wolfgang; Cox, Anne

2009-02-18

72

Emphysema and Alpha-1  

MedlinePLUS

... be carriers of the defective gene that causes Alpha-1. About 100,000 people in the U.S. ... of people with COPD may actually have undiagnosed Alpha-1 deficiency. © 2014 American Association for Respiratory Care

73

GROSS ALPHA RADIUM REGULATION  

EPA Science Inventory

The determination of concentrations of natural radioactivity in public water supplies begins with the measurement of the gross alpha particle activity. The gross alpha activity measurement is used as a screening technique. The gross alpha particle activity measurement may be su...

74

Graph characterization via Ihara coefficients.  

PubMed

The novel contributions of this paper are twofold. First, we demonstrate how to characterize unweighted graphs in a permutation-invariant manner using the polynomial coefficients from the Ihara zeta function, i.e., the Ihara coefficients. Second, we generalize the definition of the Ihara coefficients to edge-weighted graphs. For an unweighted graph, the Ihara zeta function is the reciprocal of a quasi characteristic polynomial of the adjacency matrix of the associated oriented line graph. Since the Ihara zeta function has poles that give rise to infinities, the most convenient numerically stable representation is to work with the coefficients of the quasi characteristic polynomial. Moreover, the polynomial coefficients are invariant to vertex order permutations and also convey information concerning the cycle structure of the graph. To generalize the representation to edge-weighted graphs, we make use of the reduced Bartholdi zeta function. We prove that the computation of the Ihara coefficients for unweighted graphs is a special case of our proposed method for unit edge weights. We also present a spectral analysis of the Ihara coefficients and indicate their advantages over other graph spectral methods. We apply the proposed graph characterization method to capturing graph-class structure and clustering graphs. Experimental results reveal that the Ihara coefficients are more effective than methods based on Laplacian spectra. PMID:21118772

Ren, Peng; Wilson, Richard C; Hancock, Edwin R

2011-02-01

75

Extinction Coefficient at Zero Concentration  

Microsoft Academic Search

THE use of extinction coefficients to characterize substances depends on the validity of Lambert-Beer's law. The following shows that a constant-extinction coefficient at zero concentration-which is the tangent to the extinction-concentration curve at zero concentration, may be calculated even if Lambert-Beer's law is not followed.

J. Fog

1962-01-01

76

Fuel Temperature Coefficient of Reactivity  

SciTech Connect

A method for measuring the fuel temperature coefficient of reactivity in a heterogeneous nuclear reactor is presented. The method, which is used during normal operation, requires that calibrated control rods be oscillated in a special way at a high reactor power level. The value of the fuel temperature coefficient of reactivity is found from the measured flux responses to these oscillations. Application of the method in a Savannah River reactor charged with natural uranium is discussed.

Loewe, W.E.

2001-07-31

77

Recombination coefficients for iron ions  

NASA Technical Reports Server (NTRS)

Radiative recombination coefficients for all Fe ions are calculated by use of the Milne relation of detailed balance. Analytic fits are made to the dielectronic recombination rates computed by Jacobs (1977) and the Burgess general formula (1965). Higher level rates are treated hydrogenically by a quantum defect method based on the energies of the levels. Recombination coefficients for Fe I to Fe 26 are listed.

Woods, D. T.; Shull, J. M.; Sarazin, C. L.

1981-01-01

78

[Studies on 17 alpha, 20 alpha-dihydroxy-4-pregnen-3-one in non-pregnant and pregnant women by a new radioimmunoassay system].  

PubMed

17 alpha, 20 alpha-dihydroxy-4-pregnen-3-one (17 alpha, 20 alpha-P) is reportedly a hyper-tensinogenic substance in a model of ACTH induced hypertension in sheep (Scoggins et al). This steroid has not previously been measured in Japan. We have developed a new radioimmunoassay (RIA) system for 17 alpha, 20 alpha-P, and measured this steroid in peripheral blood samples from non-pregnant and pregnant women. In this clinical investigation concentrations of 17 alpha-hydroxyprogesterone (17 alpha-OHP) and progesterone (P) were also measured in the same clinical samples. Specific anti-serum against 17 alpha, 20 alpha-P-3-carboxymethyloxime-BSA was generated in rabbits. Cross-reactions with 5-pregnen-3 beta, 17 alpha 20 alpha-triol (17 alpha, 20 alpha-P5) and 17 alpha-OHP were 42 and 2.4%, respectively. Other steroids showed cross-reactivity of less than 1%. As an internal standard dexamethasone (500 ng/100 microliter) was added to the samples which were extracted twice with 6 volumes of dichloromethane. Separation of the plasma extract was performed by high performance liquid chromatography (HPLC) with the ODS column in the solvent system, acetonitrile:water = 55:45. Eluates of the 17 alpha, 20 alpha-P and 17 alpha-OHP fractions were collected separately and the solvent was evaporated in vacuo. RIA was carried out on each extract with specific anti-sera. RIA of P was performed independently using the anti-P-3-CMO-BSA antiserum; 0.1 ml of serum was extracted with n-hexane and subjected to RIA without chromatography. The coefficient of variation for intra- and interassay (n = 10) were 8.5 and 11.7% for 17 alpha, 20 alpha-P; 7.2 and 12.1% for 17-OHP and 10.5 and 14.0% for P, respectively. The recovery rates of 17 alpha, 20 alpha-P, 17 alpha-OHP and P were 95 +/- 1.5, 93.2 +/- 3.5 and 97.5 +/- 4.2%, respectively. With the use of this method, 17 alpha, 20 alpha-P was measured in the blood samples from the menstrual cycle and normal pregnancy. The mean serum 17 alpha, 20 alpha-P concentrations +/- SD in the follicular, ovulatory and luteal phases, and in the first, second and third trimesters were; 76 +/- 6.0, 100 +/- 31, 101 +/- 6.4, 226 +/- 80, 151 +/- 48 and 367 +/- 99 pg/ml, respectively.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:3609396

Satoh, K

1987-03-20

79

Measurement Properties of the Malay Version of the Golombok-Rust Inventory of Marital State (GRIMS) Among Urological Patients  

Microsoft Academic Search

To validate the Malay version of the Golombok-Rust Inventory of Marital State (GRIMS) among urological patients. The reliability and Internal consistency were assessed using the test-retest method and Cronbach's alpha. Sensitivity to change was assessed by mean differences and by the effect size. Internal consistency was excellent (Cronbach's alpha value • 0.43 to 1.00). Test-retest correlation coefficient and Intraciass correlation

Quek Kia Fatt; Hassan Razack; Loh Chit Sin

2001-01-01

80

The generalized liquid drop model alpha-decay formula: Predictability analysis and superheavy element alpha half-lives  

SciTech Connect

The predictive accuracy of the generalized liquid drop model (GLDM) formula for alpha-decay half-lives has been investigated in a detailed manner and a variant of the formula with improved coefficients is proposed. The method employs the experimental alpha half-lives of the well-known alpha standards to obtain the coefficients of the analytical formula using the experimental Q{sub {alpha}} values (the DSR-E formula), as well as the finite range droplet model (FRDM) derived Q{sub {alpha}} values (the FRDM-FRDM formula). The predictive accuracy of these formulae was checked against the experimental alpha half-lives of an independent set of nuclei (TEST) that span approximately the same Z, A region as the standards and possess reliable alpha spectroscopic data, and were found to yield good results for the DSR-E formula but not for the FRDM-FRDM formula. The two formulae were used to obtain the alpha half-lives of superheavy elements (SHE) and heavy nuclides where the relative accuracy was found to be markedly improved for the FRDM-FRDM formula, which corroborates the appropriateness of the FRDM masses and the GLDM prescription for high Z, A nuclides. Further improvement resulted, especially for the FRDM-FRDM formula, after a simple linear optimization over the calculated and experimental half-lives of TEST was used to re-calculate the half-lives of the SHE and heavy nuclides. The advantage of this optimization was that it required no re-calculation of the coefficients of the basic DSR-E or FRDM-FRDM formulae. The half-lives for 324 medium-mass to superheavy alpha decaying nuclides, calculated using these formulae and the comparison with experimental half-lives, are presented.

Dasgupta-Schubert, N. [Instituto de Investigaciones Quimico-Biologicas, Universidad Michoacana de San Nicolas de Hidalgo, Cd. Universitaria, Morelia, Michoacan C.P. 58060 (Mexico)], E-mail: nita@ifm.umich.mx; Reyes, M.A. [Department of Electrical Engineering, University of Texas Pan American, Edinburg, TX 78539 (United States)

2007-11-15

81

Orthogonality of spherical harmonic coefficients  

NASA Technical Reports Server (NTRS)

Orthogonality relations are obtained for the spherical harmonic coefficients of functions defined on the surface of a sphere. Following a brief discussion of the orthogonality of Fourier series coefficients, consideration is given to the values averaged over all orientations of the coordinate system of the spherical harmonic coefficients of a function defined on the surface of a sphere that can be expressed in terms of Legendre polynomials for the special case where the function is the sum of two delta functions located at two different points on the sphere, and for the case of an essentially arbitrary function. It is noted that the orthogonality relations derived have found applications in statistical studies of the geomagnetic field.

Mcleod, M. G.

1980-01-01

82

Dynamic model with scale-dependent coefficients in the viscous range  

NASA Technical Reports Server (NTRS)

The standard dynamic procedure is based on the scale-invariance assumption that the model coefficient C is the same at the grid and test-filter levels. In many applications this condition is not met, e.g. when the filter-length, delta, approaches the Kolmogorov scale, and C(delta approaches eta) approaches O. Using a priori tests, we show that the standard dynamic model yields the coefficient corresponding to the test-filter scale (alpha delta) instead of the grid-scale (delta). Several approaches to account for scale dependence are examined and/or tested in large eddy simulation of isotropic turbulence: (a) take the limit alpha approaches 1; (b) solve for two unknown coefficients C(Delta) and C(alpha delta) in the least-square-error formulation; (c) the 'bi-dynamic model', in which two test-filters (e.g. at scales 2(delta) and 4(delta) are employed to gain additional information on possible scale-dependence of the coefficient, and an improved estimate for the grid-level coefficient is obtained by extrapolation, (d) use theoretical predictions for the ratio C(alpha delta)/C(delta) and dynamically solve for C(delta). None of these options is found to be entirely satisfactory, although the last approach appears applicable to the viscous range.

Meneveau, C.; Lund, T. S.

1996-01-01

83

Alpha factor analysis  

Microsoft Academic Search

A distinction is made between statistical inference and psychometric inference in factor analysis. After reviewing Rao's canonical factor analysis (CFA), a fundamental statistical method of factoring, a new method of factor analysis based upon the psychometric concept of generalizability is described. This new procedure (alpha factor analysis, AFA) determines factors which have maximum generalizability in the Kuder-Richardson, or alpha, sense.

Henry F. Kaiser; John Caffrey

1965-01-01

84

High alpha Inlets.  

National Technical Information Service (NTIS)

The high alpha inlet research effort at Lewis is part of the High Alpha Technology Program (HATP) within NASA. A key goal of HATP is to develop concepts that provide a high level of control and maneuverability for high performance aircraft at low subsonic...

R. R. Burley B. H. Anderson C. F. Smith G. J. Harloff

1991-01-01

85

Liver and Alpha-1 Antitrypsin Deficiency (Alpha-1)  

MedlinePLUS

... protein over time leads to liver damage. How Common Is Liver Disease In People With Alpha-1 And In Alpha- ... or scarring of the liver, is the most common liver disease in adults related to Alpha-1. The risk ...

86

Method for determining damping coefficients  

NASA Astrophysics Data System (ADS)

There is disclosed a method for determining damping coefficients, the method including the steps of providing a damper assembly including a bar of known parameters, and a viscous damper, wherein a first end of the bar is disposed in the viscous damper while the second end of the bar is free, applying a known force to the second end of the bar in a direction toward the first end of the bar, measuring the response function of the assembly, comprising the ratio of the bar acceleration to the applied force, determining the eigenvalues of the response function, and from the eigenvalues computing the damping coefficient of the damper assembly.

Austin, Stephen A.; Hull, Andrew J.; Hurdis, David A.; Kasper, Kent D.

1995-05-01

87

Flow coefficients of monosleeve valves  

NASA Technical Reports Server (NTRS)

The flow coefficients of the intake and the exhaust ports of a sleeve-valve cylinder were measured by attaching the cylinder to a large tank and measuring the changes in pressure and temperature in the tank that were caused by short periods of air flow through the valve ports. The derivation of the equations on which the flow coefficients are based is given. The distribution of total pressure in the arms of the sleeve-valve intake manifold was measured. The arms are found to have as little as 75 percent of the total pressure within the manifold entrance.

Waldron, C D

1941-01-01

88

Alpha-particle diagnostics  

SciTech Connect

This paper will focus on the state of development of diagnostics which are expected to provide the information needed for {alpha}- physics studies in the future. Conventional measurement of detailed temporal and spatial profiles of background plasma properties in DT will be essential for such aspects as determining heating effectiveness, shaping of the plasma profiles and effects of MHD, but will not be addressed here. This paper will address (1) the measurement of the neutron source, and hence {alpha}-particle birth profile, (2) measurement of the escaping {alpha}-particles and (3) measurement of the confined {alpha}-particles over their full energy range. There will also be a brief discussion of (4) the concerns about instabilities being generated by {alpha}-particles and the methods necessary for measuring these effects. 51 refs., 10 figs.

Young, K.M.

1991-01-01

89

Imaging alpha particle detector  

DOEpatents

A method and apparatus for detecting and imaging alpha particles sources is described. A conducting coated high voltage electrode (1) and a tungsten wire grid (2) constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source (3) to be quantitatively or qualitatively analyzed. A thin polyester film window (4) allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

Anderson, David F. (Los Alamos, NM)

1985-01-01

90

Reexamination of the {alpha}-{alpha}''fishbone'' potential  

SciTech Connect

The fishbone potential of composite particles simulates the Pauli effect by nonlocal terms. We determine the {alpha}-{alpha} fishbone potential by simultaneously fitting to two-{alpha} resonance energies, experimental phase shifts, and three-{alpha} binding energies. We found that, essentially, a simple Gaussian can provide a good description of two-{alpha} and three-{alpha} experimental data without invoking three-body potentials.

Day, J. P.; McEwen, J. E.; Elhanafy, M.; Smith, E.; Woodhouse, R.; Papp, Z. [Department of Physics and Astronomy, California State University Long Beach, Long Beach, California (United States)

2011-09-15

91

Measurement of Impact Ionization Coefficients in Gallium Nitride  

NASA Astrophysics Data System (ADS)

GaN has been recognized as a potential semiconductor for high temperature, high frequency and high power applications. Due to its wide bandgap, GaN exhibits high critical electric fields, which are suitable to sustain high breakdown voltages in power electronic devices. In order to obtain a good understanding of the breakdown characteristics of a power device, it is important to know the impact ionization coefficients of electrons and holes as a function of the electric field in the semiconductor. In this work, electron and hole impact ionization coefficients have been accurately measured in both GaN epitaxial layers grown on bulk GaN substrates and GaN epitaxial layers grown on Sapphire substrates using the pulsed electron beam induced current technique. Using Chynoweth's equation (alpha = a e-b/E), measurements for GaN epitaxial layer grown on bulk GaN substrates gave an aN value of 1.5x105 cm-1 and a bN value of 1.413x107 V/cm for the impact ionization coefficient of electrons in GaN at room temperature. For the impact ionization coefficients of holes in GaN, the values of aP and bP were found to be 6.4x105 cm-1 and 1.454x107 V/cm, respectively. An analytical solution of the form alpha = mEn for the variation of the impact ionization coefficients as a function of the electric field was derived, which is useful for analytical calculation of the breakdown voltages in GaN. For Chynoweth's equation (alpha = a e-b/E), measurements for GaN epitaxial layers grown on Sapphire substrates gave an aN value of 9.17x105 cm-1 and a bN value of 1.722x107 V/cm for the impact ionization coefficient for electrons at room temperature. For the impact ionization coefficients for holes at room temperature, the values of aP and bP were found to be 8.7x105 cm-1 and 1.464x107 V/cm, respectively. The values for both coefficients are larger than those measured for GaN grown on GaN substrates. The temperature dependence of the electron and hole impact ionization coefficients as a function of the electric field has been accurately measured for both GaN epitaxial layers grown on bulk GaN substrates and GaN epitaxial layers grown on Sapphire substrates. The impact ionization coefficients for both electrons and holes are observed to decrease with increasing temperature. This is consistent with the measured increase in the breakdown voltage with temperature for high voltage Schottky barrier diodes. This is an important observation demonstrating that stable power devices can be fabricated from Gallium Nitride. Electron Beam Induced Current (EBIC) technique was employed in order to understand the role of defects on the breakdown characteristics of GaN. The impact ionization coefficients for electrons and holes measured at the defective site were found to be higher than those measured at a non-defective site. These results indicate that the breakdown voltage of GaN devices can be reduced due to the presence of defects.

Ozbek, Ayse Merve

92

Virial Coefficients for Gaseous Hydrocarbons.  

National Technical Information Service (NTIS)

A compilation of second, third and, in some cases, fourth virial coefficients of the gaseous hydrocarbons is presented. Most of the values listed have been obtained from a re-analysis of the published experimental p-V-T data. However, where the publicatio...

A. Pompe T. H. Spurling

1974-01-01

93

Spearman Rank Order Correlation Coefficient  

NSDL National Science Digital Library

This page will calculate r_s , the Spearman rank- order correlation coefficient, for a bivariate set of paired XY rankings. As the page opens, you will be prompted to enter the number of items for which there are paired rankings. If you are starting out with raw (unranked) data, the necessary rank-ordering will be performed automatically.

Lowry, Richard, 1940-

2008-06-25

94

Reliability Estimation Using Validity Coefficients.  

ERIC Educational Resources Information Center

Occasionally situations arise in which a measurement does not lend itself to such traditional methods of reliability estimation as the test-retest, parallel-test, or internal consistency methods. This paper proposes basing reliability estimation in such situations on estimates of validity coefficients as lower bounds. (Author/LMO)

Krammer, Hein, P. M.; Van Der Linden, Wim J.

1986-01-01

95

Geometrical content of Leslie coefficients  

NASA Astrophysics Data System (ADS)

In this work, we will study how the effective geometry acquired by nematic molecules under thermal vibration contribute to the determination of the Leslie coefficients. To do this, we will divide this work in two sections. In the first section, we present the geometrical fundamentals of the so-called Hess-Baalss (HB) approach [D. Baalss and S. Hess, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.57.86 57, 86 (1986)] where we show that its basic assumptions can be understood as a geometrical interpretation of de Gennes’ passage from the microscopic to the macroscopic order parameter. In the second section, we use an extended version of the HB approach [M. Simões, K. Yamaguti, and A. J. Palangana, Phys. Rev. EPHRVAO1539-375510.1103/PhysRevE.80.061701 80, 061701 (2009)] to obtain the geometrical contribution to each Leslie coefficient. Our results will be compared with experimental data, and we will show that the Miesowicz’s coefficients are connected as long as the ratio ?3/?4 between these Leslie coefficients can be considered small.

Simões, M.; da Silva, J. L. Correia

2011-05-01

96

Aerodynamic coefficients and transformation tables  

NASA Technical Reports Server (NTRS)

The problem of the transformation of numerical values expressed in one system of units into another set or system of units frequently arises in connection with aerodynamic problems. Report contains aerodynamic coefficients and conversion tables needed to facilitate such transformation. (author)

Ames, Joseph S

1918-01-01

97

Identities for generalized hypergeometric coefficients  

SciTech Connect

Generalizations of hypergeometric functions to arbitrarily many symmetric variables are discussed, along with their associated hypergeometric coefficients, and the setting within which these generalizations arose. Identities generalizing the Euler identity for {sub 2}F{sub 1}, the Saalschuetz identity, and two generalizations of the {sub 4}F{sub 3} Bailey identity, among others, are given. 16 refs.

Biedenharn, L.C.; Louck, J.D.

1991-01-01

98

Weyl Coefficients in SU(3)  

Microsoft Academic Search

The Weyl coefficients are by definition the matrix elements of the Weyl operators in SU(3). They are found to be generalized hypergeometric series of the type 4F3, and can be written down in a simple way from the Gel'fand patterns involved.

Klaus J. Lezuo

1967-01-01

99

Logistic Regression with Random Coefficients.  

ERIC Educational Resources Information Center

An approximation to the likelihood for the generalized linear models with random coefficients is derived and is the basis for an approximate Fisher scoring algorithm. The method is illustrated on the logistic regression model for one-way classification, but it has an extension to the class of generalized linear models and to more complex data…

Longford, Nicholas T.

100

Evaluation of the Biot Coefficients.  

National Technical Information Service (NTIS)

The Biot equations are the most promising approach for modeling the propagation of acoustic waves in ocean sediments. A method has been developed by Bedford, Costley and Stern for determining the drag and virtual mass coefficients in Biot's equations as f...

B. Yavari A. Bedford

1987-01-01

101

Neural Network Prediction of New Aircraft Design Coefficients  

NASA Technical Reports Server (NTRS)

This paper discusses a neural network tool for more effective aircraft design evaluations during wind tunnel tests. Using a hybrid neural network optimization method, we have produced fast and reliable predictions of aerodynamical coefficients, found optimal flap settings, and flap schedules. For validation, the tool was tested on a 55% scale model of the USAF/NASA Subsonic High Alpha Research Concept aircraft (SHARC). Four different networks were trained to predict coefficients of lift, drag, moment of inertia, and lift drag ratio (C(sub L), C(sub D), C(sub M), and L/D) from angle of attack and flap settings. The latter network was then used to determine an overall optimal flap setting and for finding optimal flap schedules.

Norgaard, Magnus; Jorgensen, Charles C.; Ross, James C.

1997-01-01

102

Consistent transport coefficients in astrophysics  

NASA Technical Reports Server (NTRS)

A consistent theory for dealing with transport phenomena in stellar atmospheres starting with the kinetic equations and introducing three cases (LTE, partial LTE, and non-LTE) was developed. The consistent hydrodynamical equations were presented for partial-LTE, the transport coefficients defined, and a method shown to calculate them. The method is based on the numerical solution of kinetic equations considering Landau, Boltzmann, and Focker-Planck collision terms. Finally a set of results for the transport coefficients derived for a partially ionized hydrogen gas with radiation was shown, considering ionization and recombination as well as elastic collisions. The results obtained imply major changes is some types of theoretical model calculations and can resolve some important current problems concerning energy and mass balance in the solar atmosphere. It is shown that energy balance in the lower solar transition region can be fully explained by means of radiation losses and conductive flux.

Fontenla, Juan M.; Rovira, M.; Ferrofontan, C.

1986-01-01

103

High temperature Seebeck coefficient metrology  

SciTech Connect

We present an overview of the challenges and practices of thermoelectric metrology on bulk materials at high temperature (300 to 1300 K). The Seebeck coefficient, when combined with thermal and electrical conductivity, is an essential property measurement for evaluating the potential performance of novel thermoelectric materials. However, there is some question as to which measurement technique(s) provides the most accurate determination of the Seebeck coefficient at high temperature. This has led to the implementation of nonideal practices that have further complicated the confirmation of reported high ZT materials. To ensure meaningful interlaboratory comparison of data, thermoelectric measurements must be reliable, accurate, and consistent. This article will summarize and compare the relevant measurement techniques and apparatus designs required to effectively manage uncertainty, while also providing a reference resource of previous advances in high temperature thermoelectric metrology.

Martin, J. [Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Tritt, T. [Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29634 (United States); Uher, C. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2010-12-15

104

Portable vapor diffusion coefficient meter  

DOEpatents

An apparatus for measuring the effective vapor diffusion coefficient of a test vapor diffusing through a sample of porous media contained within a test chamber. A chemical sensor measures the time-varying concentration of vapor that has diffused a known distance through the porous media. A data processor contained within the apparatus compares the measured sensor data with analytical predictions of the response curve based on the transient diffusion equation using Fick's Law, iterating on the choice of an effective vapor diffusion coefficient until the difference between the predicted and measured curves is minimized. Optionally, a purge fluid can forced through the porous media, permitting the apparatus to also measure a gas-phase permeability. The apparatus can be made lightweight, self-powered, and portable for use in the field.

Ho, Clifford K. (Albuquerque, NM)

2007-06-12

105

Influence of alpha-cluster formation on alpha decay  

Microsoft Academic Search

Dependence of alpha-cluster and pp- and nn-cluster formation on high-lying configurations (continuum) in nuclei is studied. Its importance for alpha-decay calculations is discussed. RADIOACTIVITY alpha-decay, alpha-transfer reactions, high-lying configurations (continuum).

F. A. Janouch; R. J. Liotta

1983-01-01

106

Alpha Particle Diagnostic  

SciTech Connect

The study of burning plasmas is the next frontier in fusion energy research, and will be a major objective of the U.S. fusion program through U.S. collaboration with our international partners on the ITER Project. For DT magnetic fusion to be useful for energy production, it is essential that the energetic alpha particles produced by the fusion reactions be confined long enough to deposit a significant fraction of their initial ~3.5 MeV energy in the plasma before they are lost. Development of diagnostics to study the behavior of energetic confined alpha particles is a very important if not essential part of burning plasma research. Despite the clear need for these measurements, development of diagnostics to study confined the fast confined alphas to date has proven extremely difficult, and the available techniques remain for the most part unproven and with significant uncertainties. Research under this grant had the goal of developing diagnostics of fast confined alphas, primarily based on measurements of the neutron and ion tails resulting from alpha particle knock-on collisions with the plasma deuterium and tritium fuel ions. One of the strengths of this approach is the ability to measure the alphas in the hot plasma core where the interesting ignition physics will occur.

Fisher, Ray, K.

2009-05-13

107

Some comments on Sabine absorption coefficient (L)  

Microsoft Academic Search

The case of a nonzero reverberation time when all absorptive surfaces in a room have values of Sabine absorption coefficient of one, the existence of values of the coefficient that are larger than one, and the difference of the coefficient from the statistical absorption coefficient, are well known. So far, the reasons for these phenomena are still unclear. This letter

K. S. Sum

2005-01-01

108

Nature of optical remote sensing coefficient  

Microsoft Academic Search

The remote sensing coefficient or radiance reflection coefficient is a principal product of atmospheric correction algorithms applied to the remotely measured optical images of the ocean. This coefficient contains information about angular structure of light radiance, roughness of the ocean surface, and optical properties of the water. This presentation analyses remote sensing coefficient and presents it as a product of

Vladimir I. Haltrin

2004-01-01

109

Symmetries and Recursion Operators of Variable Coefficient Korteweg-de Vries Equations.  

National Technical Information Service (NTIS)

The infinitely many symmetries and recursion operators are constructed for two recently introduced variable coefficient Korteweg-de Vries equations, u/sub t/+ alpha t/sup n/uu/sub x/+ beta t/sup 2n+1/u/sub xxx/=0 and v/sub t/+ beta t/sup 2n+1/(v/sub 3/-6v...

B. V. Baby

1987-01-01

110

Temperature Dependence of J(Ff) in 2-Fluoro-alpha-Chloro-alpha, alpha-Difluoro-Toluene and 2-Fluoro-alpha, alpha-Dichloro-alpha-Fluoro-Toluene.  

National Technical Information Service (NTIS)

The F-F coupling constants J(FF) between the fluorine atom at the 2-position and the fluorines in the CFCl2 and CF2Cl groups were measured and found to have an appreciable temperature dependence in 2-fluoro-alpha, alpha-dichloro-alpha-fluoro-toluene and 2...

J. Jonas L. Borowski H. S. Gutowsky

1967-01-01

111

Alpha-Particle Gas-Pressure Sensor  

NASA Technical Reports Server (NTRS)

An approximate model was developed to establish design curves for the saturation region and a more complete model developed to characterize the current-voltage curves for an alpha-particle pressure sensor. A simple two-parameter current-voltage expression was developed to describe the dependence of the ion current on pressure. The parameters are the saturation-current pressure coefficient and mu/D, the ion mobility/diffusion coefficient. The sensor is useful in the pressure range between 0.1 and 1000 mb using a 1 - mu Ci(241) Am source. Experimental results, taken between 1 and up to 200 mb, show the sensor operates with an anode voltage of 5 V and a sensitivity of 20 fA/mb in nitrogen.

Buehler, M. C.; Bell, L. D.; Hecht, M. H.

1996-01-01

112

THE TEMPERATURE COEFFICIENT OF PHAGOCYTOSIS  

PubMed Central

1. The experiments of Madsen and Watabiki on the effect of temperature on the phagocytosis of bacteria are discussed and a new analysis of their curves is given, showing that the rate of phagocytosis is very nearly a logarithmic function of the temperature from 0° to 35°C.; i.e., Q10 is constant over that range and is equal to 2.0. 2. New experiments are reported on the effect of temperature on the phagocytosis of quartz and carbon particles of uniform sizes, showing a marked increase in the temperature coefficient below 30°C.

Fenn, Wallace O.

1922-01-01

113

THE TEMPERATURE COEFFICIENT OF PHAGOCYTOSIS.  

PubMed

1. The experiments of Madsen and Watabiki on the effect of temperature on the phagocytosis of bacteria are discussed and a new analysis of their curves is given, showing that the rate of phagocytosis is very nearly a logarithmic function of the temperature from 0 degrees to 35 degrees C.; i.e., Q(10) is constant over that range and is equal to 2.0. 2. New experiments are reported on the effect of temperature on the phagocytosis of quartz and carbon particles of uniform sizes, showing a marked increase in the temperature coefficient below 30 degrees C. PMID:19871938

Fenn, W O

1922-01-20

114

Measurements of thermal accommodation coefficients.  

SciTech Connect

A previously-developed experimental facility has been used to determine gas-surface thermal accommodation coefficients from the pressure dependence of the heat flux between parallel plates of similar material but different surface finish. Heat flux between the plates is inferred from measurements of temperature drop between the plate surface and an adjacent temperature-controlled water bath. Thermal accommodation measurements were determined from the pressure dependence of the heat flux for a fixed plate separation. Measurements of argon and nitrogen in contact with standard machined (lathed) or polished 304 stainless steel plates are indistinguishable within experimental uncertainty. Thus, the accommodation coefficient of 304 stainless steel with nitrogen and argon is estimated to be 0.80 {+-} 0.02 and 0.87 {+-} 0.02, respectively, independent of the surface roughness within the range likely to be encountered in engineering practice. Measurements of the accommodation of helium showed a slight variation with 304 stainless steel surface roughness: 0.36 {+-} 0.02 for a standard machine finish and 0.40 {+-} 0.02 for a polished finish. Planned tests with carbon-nanotube-coated plates will be performed when 304 stainless-steel blanks have been successfully coated.

Rader, Daniel John; Castaneda, Jaime N.; Torczynski, John Robert; Grasser, Thomas W.; Trott, Wayne Merle

2005-10-01

115

Analysis of fluorophore diffusion by continuous distributions of diffusion coefficients: application to photobleaching measurements of multicomponent and anomalous diffusion.  

PubMed Central

Fluorescence recovery after photobleaching (FRAP) is widely used to measure fluorophore diffusion in artificial solutions and cellular compartments. Two new strategies to analyze FRAP data were investigated theoretically and applied to complex systems with anomalous diffusion or multiple diffusing species: 1) continuous distributions of diffusion coefficients, alpha(D), and 2) time-dependent diffusion coefficients, D(t). A regression procedure utilizing the maximum entropy method was developed to resolve alpha(D) from fluorescence recovery curves, F(t). The recovery of multi-component alpha(D) from simulated F(t) with random noise was demonstrated and limitations of the method were defined. Single narrow Gaussian alpha(D) were recovered for FRAP measurements of thin films of fluorescein and size-fractionated FITC-dextrans and Ficolls, and multi-component alpha(D) were recovered for defined fluorophore mixtures. Single Gaussian alpha(D) were also recovered for solute diffusion in viscous media containing high dextran concentrations. To identify anomalous diffusion from FRAP data, a theory was developed to compute F(t) and alpha(D) for anomalous diffusion models defined by arbitrary nonlinear mean-squared displacement versus time relations. Several characteristic alpha(D) profiles for anomalous diffusion were found, including broad alpha(D) for subdiffusion, and alpha(D) with negative amplitudes for superdiffusion. A method to deduce apparent D(t) from F(t) was also developed and shown to provide useful complementary information to alpha(D). alpha(D) and D(t) were determined from photobleaching measurements of systems with apparent anomalous subdiffusion (nonuniform solution layer) and superdiffusion (moving fluid layer). The results establish a practical strategy to characterize complex diffusive phenomena from photobleaching recovery measurements.

Periasamy, N; Verkman, A S

1998-01-01

116

Analysis of fluorophore diffusion by continuous distributions of diffusion coefficients: application to photobleaching measurements of multicomponent and anomalous diffusion.  

PubMed

Fluorescence recovery after photobleaching (FRAP) is widely used to measure fluorophore diffusion in artificial solutions and cellular compartments. Two new strategies to analyze FRAP data were investigated theoretically and applied to complex systems with anomalous diffusion or multiple diffusing species: 1) continuous distributions of diffusion coefficients, alpha(D), and 2) time-dependent diffusion coefficients, D(t). A regression procedure utilizing the maximum entropy method was developed to resolve alpha(D) from fluorescence recovery curves, F(t). The recovery of multi-component alpha(D) from simulated F(t) with random noise was demonstrated and limitations of the method were defined. Single narrow Gaussian alpha(D) were recovered for FRAP measurements of thin films of fluorescein and size-fractionated FITC-dextrans and Ficolls, and multi-component alpha(D) were recovered for defined fluorophore mixtures. Single Gaussian alpha(D) were also recovered for solute diffusion in viscous media containing high dextran concentrations. To identify anomalous diffusion from FRAP data, a theory was developed to compute F(t) and alpha(D) for anomalous diffusion models defined by arbitrary nonlinear mean-squared displacement versus time relations. Several characteristic alpha(D) profiles for anomalous diffusion were found, including broad alpha(D) for subdiffusion, and alpha(D) with negative amplitudes for superdiffusion. A method to deduce apparent D(t) from F(t) was also developed and shown to provide useful complementary information to alpha(D). alpha(D) and D(t) were determined from photobleaching measurements of systems with apparent anomalous subdiffusion (nonuniform solution layer) and superdiffusion (moving fluid layer). The results establish a practical strategy to characterize complex diffusive phenomena from photobleaching recovery measurements. PMID:9649418

Periasamy, N; Verkman, A S

1998-07-01

117

Varying-{alpha} monopoles  

SciTech Connect

We study static magnetic monopoles in the context of varying-{alpha} theories and show that there is a group of models for which the 't Hooft-Polyakov solution is still valid. Nevertheless, in general static magnetic monopole solutions in varying-{alpha} theories depart from the classical 't Hooft-Polyakov solution with the electromagnetic energy concentrated inside the core seeding spatial variations of the fine-structure constant. We show that Equivalence Principle constraints impose tight limits on the allowed variations of {alpha} induced by magnetic monopoles which confirms the difficulty to generate significant spatial variation of the fine-structure constant found in previous works. This is true even in the most favorable case where magnetic monopoles are the source for these variations.

Menezes, J.; Avelino, P.P.; Santos, C. [Centro de Fisica do Porto e Departamento de Fisica da Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007, Porto (Portugal)

2005-11-15

118

The Lyman alpha coronagraph  

NASA Technical Reports Server (NTRS)

The rocket-borne Lyman alpha coronagraph (RLAC) is to be used in the absence of a natural solar eclipse to determine coronal temperatures from measurements of the line width of Lyman-alpha and to determine neutral hydrogen densities of coronal material from the absolute intensity. The coronagraph consists of a 75-cm Fastie-Ebert scanning spectrometer with an AMR 641 photoelectric detection system, an off-axis parabolic primary mirror, and an occulting system. A special optical arrangement achieves rejection of radiation from the solar disk.

Kohl, J. L.; Reeves, E. M.; Kirkham, B.

1977-01-01

119

The Apollo Alpha Spectrometer.  

NASA Technical Reports Server (NTRS)

Located in the Science Instrument Module of Apollo 15 and 16, the Alpha Particle Spectrometer was designed to detect and measure the energy of alpha particles emitted by the radon isotopes and their daughter products. The spectrometer sensor consisted of an array of totally depleted silicon surface barrier detectors. Biased amplifier and linear gate techniques were utilized to reduce resolution degradation, thereby permitting the use of a single 512 channel PHA. Sensor identification and in-flight radioactive calibration were incorporated to enhance data reduction.

Jagoda, N.; Kubierschky, K.; Frank, R.; Carroll, J.

1973-01-01

120

Individual Activity Coefficients of Ionic Species.  

National Technical Information Service (NTIS)

Research investigations on an attempt to measure the absolute magnitude of activity coefficients of individual ionic species have been continued. In support of this objective, experimental measurements were made of the non-isothermal temperature coefficie...

G. Milazzo V. K. Sharma I. P. Reyftman

1969-01-01

121

[alpha]-Oxocarboxylic Acids  

ERIC Educational Resources Information Center

Several [alpha]-oxocarboxylic acids play key roles in metabolism in plants and animals. However, there are inconsistencies between the structures as commonly portrayed and the reported acid ionization constants, which result because the acids are predominantly hydrated in aqueous solution; that is, the predominant form is RC(OH)[subscript 2]COOH…

Kerber, Robert C.; Fernando, Marian S.

2010-01-01

122

Alpha-mannosidosis  

Microsoft Academic Search

Alpha-mannosidosis is an inherited lysosomal storage disorder characterized by immune deficiency, facial and skeletal abnormalities, hearing impairment, and intellectual disability. It occurs in approximately 1 of 500,000 live births. The children are often born apparently normal, and their condition worsens progressively. Some children are born with ankle equinus or develop hydrocephalus in the first year of life. Main features are

Dag Malm; Øivind Nilssen

2008-01-01

123

From Alpha to Omega  

ERIC Educational Resources Information Center

The Alpha point of the authors' life as a Montessori educator began in 1959, when he was a graduate student studying philosophy at Fordham University in the Bronx, New York. While studying the works of the great American philosopher William James, the author came across the writings of Maria Montessori and immediately became captivated by her…

Czaja, Paul Clement

2006-01-01

124

Thermal expansion coefficients of a 30% glass fiber filled PEEK pyrotechnic charge holder  

SciTech Connect

Pyrotechnic actuators use hollow cylindrical ceramic or plastic charge holders to electrically isolate the pyrotechnic charge from the actuator case. In a newly developed actuator, 30% glass fiber filled polyetheretherketone (PEEK) was selected as the charge holder material both for its strength and its forming properties. Because the actuators are exposed to significant temperature variations during storage and flight, a determination of the coefficient of thermal expansion, ..cap alpha.., of the charge holders was required to assure success in this, the first electroexplosive device application of PEEK. Of special interest in this project were the questions of whether ..cap alpha.. depends on the direction (with respect to flow in the mold) or on injection pressure. From the test results, the conclusions are: (1) ..cap alpha.. does depend on direction. Its value in the thickness direction is approximately twice that in either the height or circumferential direction. This is probably because the wall thickness, 0.015'', is less than the average fiber length, 0.100'', and the PEEK is, therefore, not acting as a composite in the t direction. (2) Varying the injection pressure over the range of this study has no detectable effect on ..cap alpha... This charge holder is molded into an Inconel actuator case with ..cap alpha.. = 11.4 ..mu..m/m.C. This relatively close match of ..cap alpha..'s between adjacent materials has resulted in no dimensional problems during manufacturing and environmental testing. 1 fig., 1 tab.

Donnelly, M.W.; Walters, R.R.; Miller, G.D.

1985-01-01

125

Stereoselective Synthesis of [alpha, alpha][superscript ']-Biprolines  

SciTech Connect

A means to induce dehydrodimerization of Seebach's oxazolidinone (5), the stereochemical outcome of which is entirely temperature dependent, is described. The resultant dimers 3 and 4 are precursors to (R,R)-alpha,alpha'-biproline (1) and meso-alpha,alpha'-biproline (2), respectively. An organohypobromite and an iminium halide are proposed to serve as electrophiles in the reaction with the enolate of 5 to give 3 and 4, respectively.

Vartak, Ashish P.; Young, Jr., Victor G.; Johnson, Rodney L. (Minnesota)

2010-11-10

126

M-Bonomial Coefficients and Their Identities  

ERIC Educational Resources Information Center

In this note, we introduce M-bonomial coefficients or (M-bonacci binomial coefficients). These are similar to the binomial and the Fibonomial (or Fibonacci-binomial) coefficients and can be displayed in a triangle similar to Pascal's triangle from which some identities become obvious.

Asiru, Muniru A.

2010-01-01

127

Soccer Ball Lift Coefficients via Trajectory Analysis  

ERIC Educational Resources Information Center

We performed experiments in which a soccer ball was launched from a machine while two high-speed cameras recorded portions of the trajectory. Using the trajectory data and published drag coefficients, we extracted lift coefficients for a soccer ball. We determined lift coefficients for a wide range of spin parameters, including several spin…

Goff, John Eric; Carre, Matt J.

2010-01-01

128

Temperature coefficients of rare earth permanent magnets  

Microsoft Academic Search

A new approach for calculating the temperature coefficients of magnetic parameters is proposed in order to more accurately describe high temperature characteristics of magnetic materials. Using this new approach, the “true” (or instantaneous) temperature coefficient of any magnetic parameter at a specific temperature can be determined and a plot of temperature coefficient vs. temperature can be obtained. This new type

Sam Liu; G. Edward Kuhl

1999-01-01

129

Measurement of the coefficient of thermal expansion of a cryogenic, all-sapphire, Fabry-Perot optical cavity  

Microsoft Academic Search

We present measurements of the coefficient of thermal expansion (alpha) of an all-sapphire, cryogenic, Fabry-Perot optical cavity between 5 K and 77 K. The cavity is to be used as a secondary optical frequency reference. Measurements were made by tracking the frequency of the cavity relative to a free-running Nd:YAG non-planar ring laser. We find that alpha = (1.56 +\\/-

C. T. Taylor; M. Notcutt; E. K. Wong; A. G. Mann; D. G. Blair

1996-01-01

130

ChemTeacher: Alpha Decay  

NSDL National Science Digital Library

ChemTeacher compiles background information, videos, articles, demonstrations, worksheets and activities for high school teachers to use in their classrooms. The Alpha Decay page includes resources for teaching students about the discovery and applications of alpha decay.

2011-01-01

131

Estimation of Internal Consistency Reliability When Test Parts Vary in Effective Length.  

ERIC Educational Resources Information Center

Evaluating a test's reliability often requires dividing it into 3 or more unequal parts, which causes violation of the tau equivalence assumption of Cronbach's alpha. This article presents a criterion for abandoning alpha and an approach for computing a more appropriate estimate of reliability, the Gilmer-Feldt coefficient. (Author)

Feldt, Leonard S.; Charter, Richard A.

2003-01-01

132

{alpha}-Decay half-lives, {alpha}-capture, and {alpha}-nucleus potential  

SciTech Connect

{alpha}-Decay half-lives and {alpha}-capture cross sections are evaluated in the framework of a unified model for {alpha}-decay and {alpha}-capture. In this model {alpha}-decay and {alpha}-capture are considered as penetration of the {alpha}-particle through the potential barrier formed by the nuclear, Coulomb, and centrifugal interactions between the {alpha}-particle and nucleus. The spins and parities of the parent and daughter nuclei as well as the quadrupole and hexadecapole deformations of the daughter nuclei are taken into account for evaluation of the {alpha}-decay half-lives. The {alpha}-decay half-lives for 344 nuclei and the {alpha}-capture cross sections of {sup 40}Ca, {sup 44}Ca, {sup 59}Co, {sup 208}Pb, and {sup 209}Bi agree well with the experimental data. The evaluated {alpha}-decay half-lives within the range of 10{sup -9}{<=}T{sub 1/2}{<=}10{sup 38} s for 1246 {alpha}-emitters are tabulated.

Denisov, V. Yu. [Institute for Nuclear Research, Prospect Nauki 47, 03680 Kiev (Ukraine)], E-mail: denisov@kinr.kiev.ua; Khudenko, A.A. [Institute for Nuclear Research, Prospect Nauki 47, 03680 Kiev (Ukraine)

2009-11-15

133

The effect of N2/+/ recombination on the aeronomic determination of the charge exchange rate coefficient of O/+//2D/ with N2  

NASA Technical Reports Server (NTRS)

The Atmosphere Explorer (AE) data are reexamined in the light of new laboratory measurements of the N2(+) recombination rate coefficient alpha. The new measurements support earlier measurements which yielded values of alpha significantly lower than the AE values. It is found that the values for alpha determined from the satellite data can be reconciled with the laboratory measurements, if the charge exchange rate coefficient for O(+)(2D) with N2 is less than one-quarter of that derived in the laboratory by Rutherford and Vroom (1971).

Torr, D. G.; Orsini, N.

1978-01-01

134

A Note on Using Stratified Alpha to Estimate the Composite Reliability of a Test Composed of Interrelated Nonhomogeneous Items  

ERIC Educational Resources Information Center

The relationship between stratified alpha (alpha-sub(s)) and the reliability of a test composed of interrelated nonhomogeneous items is examined. It is mathematically demonstrated that when there is congeneric equivalence within the strata or subtests, the difference between the coefficients is a function of the variances of the loadings within…

Rae, Gordon

2007-01-01

135

Microstructure and Kinetics of the Plutonium beta Implies alpha and gamma Implies alpha Transformations.  

National Technical Information Service (NTIS)

Supported-discharge cathodic etching and SEM examination techniques were developed for alpha -Pu and used to investigate the alpha microstructures formed by the beta /sub alpha / implies alpha and beta /sub gamma / implies alpha transformations in high-pu...

R. P. Allen H. W. Arrow Smith

1975-01-01

136

AlphaGalileo  

NSDL National Science Digital Library

Billed as "The world's leading resource for European research", AlphaGalileo is a tremendous resource for those with a penchant for keeping tabs on Continental scholarship that deals with science, art, technology, health, society, and the humanities. The team at AlphaGalileo includes a multilingual group of specialists and their coverage is very broad, a fact that will be welcomed in many quarters. Visitors need to complete a brief registration before using the site, and after that they can browse and search through the materials offered here. The site also allows users to perform thematic searches and the opportunity to look over press releases. It's also worth noting that after logging in, visitors can also post their own items.

137

Statistical Estimation of the Atmospheric Aerosol Absorption Coefficient Based on the Data of Optical Measurements  

SciTech Connect

The problem of the choice of the aerosol optical constants and, in particular, imaginary part of the refractive index of particles in visible and infrared (IR) wavelength ranges is very important for calculation of the global albedo of the atmosphere in climatic models. The available models of the aerosol optical constants obtained for the prescribed chemical composition of particles (see, for example, Ivlev et al. 1973; Ivlev 1982; Volz 1972), often are far from real aerosol. It is shown in (Krekov et al. 1982) that model estimates of the optical characteristics of the atmosphere depending on the correctness of real and imaginary parts of the aerosol complex refractive index can differ by some hundreds percent. It is known that the aerosol extinction coefficient {alpha}({lambda}) obtained from measurements on a long horizontal path can be represented as {alpha}({lambda})={sigma}({lambda})+{beta}({lambda}), where {sigma} is the directed light scattering coefficient, and {beta} is the aerosol absorption coefficient. The coefficient {sigma}({lambda}) is measured by means of a nephelometer. Seemingly, if measure the values {alpha}({lambda}) and {sigma}({lambda}), it is easy to determine the value {beta}({lambda}). However, in practice it is almost impossible for a number of reasons. Firstly, the real values {alpha}({lambda}) and {sigma}({lambda}) are very close to each other, and the estimate of the parameter {beta}({lambda}) is concealed by the errors of measurements. Secondly, the aerosol optical characteristics on the long path and in the local volume of nephelometer can be different, that also leads to the errors in estimating {beta}({lambda}). Besides, there are serious difficulties in performing spectral measurements of {sigma}({lambda}) in infrared wavelength range. Taking into account these circumstances, in this paper we consider the statistical technique, which makes it possible to estimate the absorption coefficient of real aerosol on the basis of analysis of simultaneous measurements of the spectral aerosol extinction coefficients {alpha}({lambda}), the directed scattering coefficient of dry aerosol {sigma}{sub 0}(0.55) and the mass concentration of aerosol containing BC (black carbon) Ms.

Uzhegov, V.N.; Kozlov, V.S.; Panchenko, M.V.; Pkhalagov, Yu.A.; Pol'kin, V.V.; Terpugova, S.A.; Shmargunov, V.P.; Yausheva, E.P.

2005-03-18

138

The alpha 21264 microprocessor  

Microsoft Academic Search

The third generation Alpha microprocessor from Compaq Computer Corporation (formerly Digital Equipment) is the 21264. This microprocessor can execute 2.0-2.4 billion instructions per second with a 500-600 MHz cycle time in a 0.35 um CMOS process, resulting in the industry-leading performance of 30+ SPECint95 and 58+ SPECfp95 in early system offerings. This paper focuses on the overall 21264 architecture, as

Richard E. Kessler

1999-01-01

139

Alpha1-Antitrypsin Deficiency: Inherited Emphysema  

MedlinePLUS

... C-ANP Alpha-1 Coordinator View full profile Alpha-1 Antitrypsin Deficiency Alpha-1 Antitrypsin Deficiency or ... Calendar Read the News View Daily Pollen Count Alpha-1 Antitrypsin Deficiency Program Doctors at National Jewish ...

140

Estimating Ordinal Reliability for Likert-Type and Ordinal Item Response Data: A Conceptual, Empirical, and Practical Guide  

ERIC Educational Resources Information Center

This paper provides a conceptual, empirical, and practical guide for estimating ordinal reliability coefficients for ordinal item response data (also referred to as Likert, Likert-type, ordered categorical, or rating scale item responses). Conventionally, reliability coefficients, such as Cronbach's alpha, are calculated using a Pearson…

Gadermann, Anne M.; Guhn, Martin; Zumbo, Bruno D.

2012-01-01

141

ORNL ALPHA MIS user's manual  

SciTech Connect

ALPHA is the most powerful and versatile of the Management Information Systems (MISs) sponsored and developed by the Finance and Materials Division of the Oak Ridge National Laboratory (ORNL). A general-purpose MIS, ALPHA can perform at least 75% of the common tasks required of MISs; it allows users to access any System 1022 data base on ORNL's PDP-10 computer to obtain information for use in the management process. This user's manual contains a description of the function of each ALPHA command and option. Besides the explanation of ALPHA's commands and options, this manual also contains a description of the ALPHA system, pointers on using ALPHA, an explanation of ALPHA's design in terms of its working vocabulary, and a sample problem.

Lovin, J.K.; Haese, R.L.; Lambdin, H.D.; Bowen, P.L.

1984-06-01

142

Effective inertial coefficient for the dinuclear regime of the exotic decay of nuclei  

SciTech Connect

Geometric and incompressibility constraint relations are used explicitly in reducing the number of collective variables of the dinuclear phase of the fissioning system to calculate the barrier penetrability factor. Consistently, we define an effective inertial coefficient for the relative motion of the fissioning system. With this inertial coefficient, half-lives of the exotic and alpha decays are successfully reproduced for all available experimental data, using only one well-controlled nuclear parameter, the nuclear radius constant. {copyright} {ital 1996 The American Physical Society.}

Duarte, S.B. [Departamento de Fisica, Universidade Federal da Paraiba, Joao Pessoa, 58059-970, Paraiba (Brazil)] [Departamento de Fisica, Universidade Federal da Paraiba, Joao Pessoa, 58059-970, Paraiba (Brazil); Goncalves, M.G. [Departamento de Ciencias Naturais, Fundacao de Ensino Superior de Sao Joao del-Rei, Pca D. Helvecio 74, Sao Joao del-Rei, 36300-300, Minas Gerais (Brazil)] [Departamento de Ciencias Naturais, Fundacao de Ensino Superior de Sao Joao del-Rei, Pca D. Helvecio 74, Sao Joao del-Rei, 36300-300, Minas Gerais (Brazil)

1996-05-01

143

Property of the Function Phi(alpha) Defined by 2 sup (N sub alpha) Equals N sub(alpha + phi(alpha)).  

National Technical Information Service (NTIS)

For every ordinal number alpha define the ordinal-valued function phi(alpha) by means of the relation 2 sup (N sub alpha) = N sub(alpha + phi(alpha)). The authors prove the following theorem which generalizes Patai's result. The assertions phi(alpha) > or...

F. Bagemihl

1970-01-01

144

Temperature dependence of the thermal-expansion coefficient of vacancies  

SciTech Connect

Self-diffusion experiments on Zn and Cd under pressure show that the thermal-expansion coefficient ..beta../sup act/ of the activation volume decreases with temperature according to the law 1/T. On the other hand in the case of Na recent calculations show that ..beta../sup act/ increases with temperature. By combining thermodynamics with a recent model (Varotsos, Ludwig, and Alexopoulos, Phys. Rev. B 18, 2683 (1978)) it is shown that ..beta../sup act/ decreases with temperature when the diffusion experiments are carried out at temperatures well above the Debye temperature. This is the case of Zn and Cd. On the other hand measurements at lower temperatures give ..cap alpha.. ..beta../sup act/ that increases with temperature as found in the case of sodium. Furthermore, a criterion is given according to which when one knows the elastic and expansivity data of a solid he can predict whether the 1/T behavior is obeyed or not.

Varotsos, P.; Alexopoulos, K.

1980-04-15

145

Adaptive alpha-beta tracking filters for ATC applications  

NASA Astrophysics Data System (ADS)

Adaptive, alpha-beta tracking filters are proposed as a convenient solution for air traffic control systems' conflicting requirement for (1) adaptive filters that will implement the tracking function of a track-while-scan (TWS) system, for aircraft motion, and (2) low computation algorithms, to meet system processing constraints. Four alpha-beta tracking filter implementation alternatives are presented, on the basis of appropriate filter coefficient values and of a strategy for switching among values, depending on the results of comparisons between radar measurements and filter outputs. Computational loading is much lower in these cases than for adaptive Kalman filters. The performance results of the four adaptive strategies are given for two typical, computer-simulated civil aircraft flight paths, and are then compared with alpha-beta nonadaptive tracking algorithm performance results.

del Re, E.; Zappa, G.

1983-10-01

146

Apparatus for measurement of coefficient of friction  

NASA Technical Reports Server (NTRS)

An apparatus designed to measure the coefficient of friction in certain controlled atmospheres is described. The coefficient of friction observed during high-load tests was nearly constant, with an average value of 0.56. This value is in general agreement with that found in the literature and also with the initial friction coefficient value of 0.67 measured during self-mated friction of 440C steel in an oxygen environment.

Slifka, A. J.; Siegwarth, J. D.; Sparks, L. L.; Chaudhuri, Dilip K.

1990-01-01

147

Substitutional and Interstitial Diffusion in alpha2-Ti3Al(O)  

NASA Technical Reports Server (NTRS)

The reaction between Al2O3 and alpha2-Ti3Al was studied with a series of Al2O3/alpha2-Ti3Al multiphase diffusion couples annealed at 900, 1000 and 1100 C. The diffusion-paths were found to strongly depend on alpha2- Ti3Al(O) composition. For alloys with low oxygen concentrations the reaction involved the reduction of Al2O3, the formation of a gamma-TiAl reaction-layer and diffusion of Al and O into the alpha2-Ti3Al substrate. Measured concentration profiles across the interaction-zone showed "up-hill" diffusion of O in alpha2-Ti3Al(O) indicating a significant thermodynamic interaction between O and Al, Ti or both. Diffusion coefficients for the interstitial O in alpha2-Ti3Al(O) were determined independently from the interdiffusion of Ti and Al on the substitutional lattice. Diffusion coefficients are reported for alpha2-Ti3Al(O) as well as gamma-TiAl. Interpretation of the results were aided with the subsequent measurement of the activities of Al, Ti and O in alpha 2-Ti3Al(O) by Knudsen effusion-cell mass spectrometry.

Copland, Evan; Young, David J.; Gleeson, Brian; Jacobson, Nathan

2007-01-01

148

Alpha-mannosidosis.  

PubMed

Alpha-mannosidosis is an inherited lysosomal storage disorder characterized by immune deficiency, facial and skeletal abnormalities, hearing impairment, and intellectual disability. It occurs in approximately 1 of 500,000 live births. The children are often born apparently normal, and their condition worsens progressively. Some children are born with ankle equinus or develop hydrocephalus in the first year of life. Main features are immune deficiency (manifested by recurrent infections, especially in the first decade of life), skeletal abnormalities (mild-to-moderate dysostosis multiplex, scoliosis and deformation of the sternum), hearing impairment (moderate-to-severe sensorineural hearing loss), gradual impairment of mental functions and speech, and often, periods of psychosis. Associated motor function disturbances include muscular weakness, joint abnormalities and ataxia. The facial trait include large head with prominent forehead, rounded eyebrows, flattened nasal bridge, macroglossia, widely spaced teeth, and prognathism. Slight strabismus is common. The clinical variability is significant, representing a continuum in severity. The disorder is caused by lysosomal alpha-mannosidase deficiency. Alpha-mannosidosis is inherited in an autosomal recessive fashion and is caused by mutations in the MAN2B1 gene located on chromosome 19 (19 p13.2-q12). Diagnosis is made by measuring acid alpha-mannosidase activity in leukocytes or other nucleated cells and can be confirmed by genetic testing. Elevated urinary secretion of mannose-rich oligosaccharides is suggestive, but not diagnostic. Differential diagnoses are mainly the other lysosomal storage diseases like the mucopolysaccharidoses. Genetic counseling should be given to explain the nature of the disease and to detect carriers. Antenatal diagnosis is possible, based on both biochemical and genetic methods. The management should be pro-active, preventing complications and treating manifestations. Infections must be treated frequently. Otolaryngological treatment of fluid in the middle ear is often required and use of hearing aids is invariably required. Early educational intervention for development of social skills is needed and physiotherapy is important to improve bodily function. Orthopedic surgery may be necessary. The long-term prognosis is poor. There is an insidiously slow progression of neuromuscular and skeletal deterioration over several decades, making most patients wheel-chair dependent. No patients manage to be completely socially independent. Many patients are over 50 years of age. PMID:18651971

Malm, Dag; Nilssen, Øivind

2008-01-01

149

Alpha-mannosidosis  

PubMed Central

Alpha-mannosidosis is an inherited lysosomal storage disorder characterized by immune deficiency, facial and skeletal abnormalities, hearing impairment, and intellectual disability. It occurs in approximately 1 of 500,000 live births. The children are often born apparently normal, and their condition worsens progressively. Some children are born with ankle equinus or develop hydrocephalus in the first year of life. Main features are immune deficiency (manifested by recurrent infections, especially in the first decade of life), skeletal abnormalities (mild-to-moderate dysostosis multiplex, scoliosis and deformation of the sternum), hearing impairment (moderate-to-severe sensorineural hearing loss), gradual impairment of mental functions and speech, and often, periods of psychosis. Associated motor function disturbances include muscular weakness, joint abnormalities and ataxia. The facial trait include large head with prominent forehead, rounded eyebrows, flattened nasal bridge, macroglossia, widely spaced teeth, and prognathism. Slight strabismus is common. The clinical variability is significant, representing a continuum in severity. The disorder is caused by lysosomal alpha-mannosidase deficiency. Alpha-mannosidosis is inherited in an autosomal recessive fashion and is caused by mutations in the MAN2B1 gene located on chromosome 19 (19 p13.2-q12). Diagnosis is made by measuring acid alpha-mannosidase activity in leukocytes or other nucleated cells and can be confirmed by genetic testing. Elevated urinary secretion of mannose-rich oligosaccharides is suggestive, but not diagnostic. Differential diagnoses are mainly the other lysosomal storage diseases like the mucopolysaccharidoses. Genetic counseling should be given to explain the nature of the disease and to detect carriers. Antenatal diagnosis is possible, based on both biochemical and genetic methods. The management should be pro-active, preventing complications and treating manifestations. Infections must be treated frequently. Otolaryngological treatment of fluid in the middle ear is often required and use of hearing aids is invariably required. Early educational intervention for development of social skills is needed and physiotherapy is important to improve bodily function. Orthopedic surgery may be necessary. The long-term prognosis is poor. There is an insidiously slow progression of neuromuscular and skeletal deterioration over several decades, making most patients wheel-chair dependent. No patients manage to be completely socially independent. Many patients are over 50 years of age.

Malm, Dag; Nilssen, ?ivind

2008-01-01

150

My Current Thoughts on Coefficient Alpha and Successor Procedures. CSE Report 643  

ERIC Educational Resources Information Center

Where the accuracy of a measurement is important, whether for scientific or practical purposes, the investigator should evaluate how much random error affects the measurement. New research may not be necessary when a procedure has been studied enough to establish how much error it involves. But, with new measures, or measures being transferred…

Cronbach, Lee J.

2004-01-01

151

Reliability of Summed Item Scores Using Structural Equation Modeling: An Alternative to Coefficient Alpha  

ERIC Educational Resources Information Center

A method is presented for estimating reliability using structural equation modeling (SEM) that allows for nonlinearity between factors and item scores. Assuming the focus is on consistency of summed item scores, this method for estimating reliability is preferred to those based on linear SEM models and to the most commonly reported estimate of…

Green, Samuel B.; Yang, Yanyun

2009-01-01

152

A Reliability Generalization Meta-Analysis of Coefficient Alpha for the Maslach Burnout Inventory  

ERIC Educational Resources Information Center

The purpose of this study was to synthesize internal consistency reliability for the subscale scores on the Maslach Burnout Inventory (MBI). The authors addressed three research questions: (a) What is the mean subscale score reliability for the MBI across studies? (b) What factors are associated with observed variance in MBI subscale score…

Wheeler, Denna L.; Vassar, Matt; Worley, Jody A.; Barnes, Laura L. B.

2011-01-01

153

Background canceling surface alpha detector  

DOEpatents

A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone. 5 figs.

MacArthur, D.W.; Allander, K.S.; Bounds, J.A.

1996-06-11

154

Drosophila melanogaster importin alpha1 and alpha3 can replace importin alpha2 during spermatogenesis but not oogenesis.  

PubMed Central

Importin alpha's mediate the nuclear transport of many classical nuclear localization signal (cNLS)-containing proteins. Multicellular animals contain multiple importin alpha genes, most of which fall into three conventional phylogenetic clades, here designated alpha1, alpha2, and alpha3. Using degenerate PCR we cloned Drosophila melanogaster importin alpha1, alpha2, and alpha3 genes, demonstrating that the complete conventional importin alpha gene family arose prior to the split between invertebrates and vertebrates. We have begun to analyze the genetic interactions among conventional importin alpha genes by studying their capacity to rescue the male and female sterility of importin alpha2 null flies. The sterility of alpha2 null males was rescued to similar extents by importin alpha1, alpha2, and alpha3 transgenes, suggesting that all three conventional importin alpha's are capable of performing the important role of importin alpha2 during spermatogenesis. In contrast, sterility of alpha2 null females was rescued only by importin alpha2 transgenes, suggesting that it plays a paralog-specific role in oogenesis. Female infertility was also rescued by a mutant importin alpha2 transgene lacking a site that is normally phosphorylated in ovaries. These rescue experiments suggest that male and female gametogenesis have distinct requirements for importin alpha2.

Mason, D Adam; Fleming, Robert J; Goldfarb, David S

2002-01-01

155

Diffusion coefficients of several aqueous alkanolamine solutions  

SciTech Connect

In absorption processes of acid gases (H[sub 2]S, CO[sub 2], COS) in alkanolamine solutions, diffusion coefficients are used for the calculation of the mass transfer rate. The Taylor dispersion technique was applied for the determination of diffusion coefficients of various systems. Experiments with the system KCl in water showed that the experimental setup provides accurate data. For the alkanolamines monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA), and di-2-propanolamine (DIPA), correlations for the diffusion coefficient as a function of temperature at different concentrations are given. A single relation for every amine has been derived which correlates the diffusion coefficients as a function of temperature and concentration. The temperature was varied between 298 and 348 K, and the concentration between 0 and 4000-5000 mol/m[sup 3]. Furthermore, a modified Stokes-Einstein relation is presented for the prediction of the diffusion coefficients in the alkanolamines in relation to the viscosity of the solvent and the diffusion coefficient at infinite dilution. The diffusion coefficients at low concentrations are compared with some available relations for the estimation of diffusion coefficients at infinite dilution, and it appears that the agreement is fairly good.

Snijder, E.D.; Riele, M.J.M. te; Versteeg, G.F.; Swaaij, W.P.M. van (Twente Univ. of Technology, Enschede (Netherlands). Dept. of Chemical Engineering)

1993-07-01

156

A Simple Measure of Price Adjustment Coefficients  

Microsoft Academic Search

One measure of market efficiency is the speed with which prices adjust to new information. The author develops a simple approach to estimating these price adjustment coefficients by using the information in return processes. This approach is used to estimate t he price adjustment coefficients for firms listed on the NYSE and the A MEX as well as for over-the-counter

Aswath Damodaran

1993-01-01

157

Betatron tune shifts and Laslett image coefficients  

SciTech Connect

The complicated expressions of betatron tune shifts in terms of Laslett image coefficients are explained. The expressions of image coefficients for a centered or off-centered beam inside an elliptical or rectangular vacuum chamber are gathered. Typos in earlier literature are corrected.

K. Y. Ng

2001-07-20

158

Pictoral Representation of Kendall's Rank Correlation Coefficient  

NSDL National Science Digital Library

This article, created by D. Wilkie of Windscale-Cumbria, explains the method of determining Kendall's Rank correlation coefficient, z, by drawing lines between corresponding points in the two rankings. The entire lesson is based around a series of diagrams which help illustrate correlation coefficients.

Wilkie, D.

2009-03-10

159

A gain-coefficient switched Alexandrite laser  

NASA Astrophysics Data System (ADS)

We report on a gain-coefficient switched Alexandrite laser. An electro-optic modulator is used to switch between high and low gain states by making use of the polarization dependent gain of Alexandrite. In gain-coefficient switched mode, the laser produces 85 ns pulses with a pulse energy of 240 mJ at a repetition rate of 5 Hz.

Lee, Chris J.; van der Slot, Peter J. M.; Boller, Klaus-J.

2013-01-01

160

CO2 absorption coefficient 1655 - 1825 Å  

Microsoft Academic Search

The COultraviolet absorption coefficients were measured in the wavelength region from 1655 to 1825 A. This region overlaps earlier work and extends into most of the previously unmeasured region between the data of Inn et al. (!953) and the data of Thompson et al. (1963). These absorption coefficients are of present interest in the theoretical development of the photochemistry for

J. Heimerl

1970-01-01

161

VES dipole--dipole filter coefficients  

Microsoft Academic Search

The conversion of sampled Schlumberger and dipole-dipole vertical electrical sounding (VES) apparent resistivity values into raised kernel function values is an important step in the interpretation of these data. This conversion involves the convolution of the sampled values, uniformly spaced on a log distance scale, with a set of filter coefficients. For Schlumberger and dipole-dipole configurations, these coefficients can be

Douglas C. Nyman; M. Landisman

1977-01-01

162

Improved Estimators for Coefficients in Linear Regression.  

National Technical Information Service (NTIS)

Point estimators for the coefficients in orthogonal linear regression which are better than the ordinary least squares estimator are obtained when at least three coefficients are to be estimated. The measure of goodness of an estimator is the sum, or weig...

S. L. Sclove

1967-01-01

163

Long range alpha particle detector  

DOEpatents

An alpha particle detector capable of detecting alpha radiation from distant sources. In one embodiment, a high voltage is generated in a first electrically conductive mesh while a fan draws air containing air molecules ionized by alpha particles through an air passage and across a second electrically conductive mesh. The current in the second electrically conductive mesh can be detected and used for measurement or alarm. The detector can be used for area, personnel and equipment monitoring.

MacArthur, Duncan W. (Los Alamos, NM); Wolf, Michael A. (Los Alamos, NM); McAtee, James L. (Los Alamos, NM); Unruh, Wesley P. (Los Alamos, NM); Cucchiara, Alfred L. (Los Alamos, NM); Huchton, Roger L. (Los Alamos, NM)

1993-01-01

164

Long range alpha particle detector  

DOEpatents

An alpha particle detector capable of detecting alpha radiation from distant sources. In one embodiment, a high voltage is generated in a first electrically conductive mesh while a fan draws air containing air molecules ionized by alpha particles through an air passage and across a second electrically conductive mesh. The current in the second electrically conductive mesh can be detected and used for measurement or alarm. The detector can be used for area, personnel and equipment monitoring.

MacArthur, D.W.; Wolf, M.A.; McAtee, J.L.; Unruh, W.P.; Cucchiara, A.L.; Huchton, R.L.

1993-02-02

165

Justification for change in AXAIR dispersion coefficients  

SciTech Connect

AXAIR is the primary dose assessment code used at the Savannah River Site (SRS) to predict doses following hypothetical releases of relatively short durations. The atmospheric dispersion coefficients currently used in AXAIR are analytical expressions developed to fit the curves in the Turner Workbook as referred to in USNRC Regulatory Guide 1.145. This report explores the ramifications and benefits of changing the dispersion coefficients to a combination of Pasquill`s lateral dispersion coefficients and Briggs` vertical dispersion coefficients. The differences in the dispersion coefficients have a minor effect on the relative air concentrations for stability classes A--D, but a significant difference is seen for classes E, F, and G.

Simpkins, A.A.

1994-02-01

166

Gas phase hydrogen permeation in alpha titanium and carbon steels  

NASA Technical Reports Server (NTRS)

Commercially pure titanium and heats of Armco ingot iron and steels containing from 0.008-1.23 w/oC were annealed or normalized and machined into hollow cylinders. Coefficients of diffusion for alpha-Ti and alpha-Fe were determined by the lag-time technique. Steady state permeation experiments yield first power pressure dependence for alpha-Ti and Sievert's law square root dependence for Armco iron and carbon steels. As in the case of diffusion, permeation data confirm that alpha-titanium is subject to at least partial phase boundary reaction control while the steels are purely diffusion controlled. The permeation rate in steels also decreases as the carbon content increases. As a consequence of Sievert's law, the computed hydrogen solubility decreases as the carbon content increases. This decreases in explained in terms of hydrogen trapping at carbide interfaces. Oxidizing and nitriding the surfaces of alpha-titanium membranes result in a decrease in the permeation rate for such treatment on the gas inlet surfaces but resulted in a slight increase in the rate for such treatment on the gas outlet surfaces. This is explained in terms of a discontinuous TiH2 layer.

Johnson, D. L.; Shah, K. K.; Reeves, B. H.; Gadgeel, V. L.

1980-01-01

167

Spatially adaptive alpha-rooting in BM3D sharpening  

NASA Astrophysics Data System (ADS)

The block-matching and 3-D filtering (BM3D) algorithm is currently one of the most powerful and effective image denoising procedures. It exploits a specific nonlocal image modelling through grouping and collaborative filtering. Grouping finds mutually similar 2-D image blocks and stacks them together in 3-D arrays. Collaborative filtering produces individual estimates of all grouped blocks by filtering them jointly, through transform-domain shrinkage of the 3-D arrays (groups). BM3D can be combined with transform-domain alpha-rooting in order to simultaneously sharpen and denoise the image. Specifically, the thresholded 3-D transform-domain coefficients are modified by taking the alpha-root of their magnitude for some alpha > 1, thus amplifying the differences both within and between the grouped blocks. While one can use a constant (global) alpha throughout the entire image, further performance can be achieved by allowing different degrees of sharpening in different parts of the image, based on content-dependent information. We propose to vary the value of alpha used for sharpening a group through weighted estimates of the low-frequency, edge, and high-frequency content of the average block in the group. This is shown to be a viable approach for image sharpening, and in particular it can provide an improvement (both visually and in terms of PSNR) over its global non-adaptive counterpart.

Mäkitalo, Markku; Foi, Alessandro

2011-02-01

168

Alpha Kappa Alpha Sorority's Reading Improvement Program for Minorities.  

ERIC Educational Resources Information Center

This document discusses the founding and establishment of Alpha Kappa Alpha Sorority's reading experience pilot project. The efforts of this project were aligned with those of Right to Read and Reading Is Fundamental (RIF). Because of the response from parents and children, plans are being made to increase present operations within the next…

Marable, June Morehead

169

Resting alpha activity predicts learning ability in alpha neurofeedback  

PubMed Central

Individuals differ in their ability to learn how to regulate the brain activity by neurofeedback. This study aimed to investigate whether the resting alpha activity can predict the learning ability in alpha neurofeedback. A total of 25 subjects performed 20 sessions of individualized alpha neurofeedback and the learning ability was assessed by three indices respectively: the training parameter changes between two periods, within a short period and across the whole training time. It was found that the resting alpha amplitude measured before training had significant positive correlations with all learning indices and could be used as a predictor for the learning ability prediction. This finding would help the researchers in not only predicting the training efficacy in individuals but also gaining further insight into the mechanisms of alpha neurofeedback.

Wan, Feng; Nan, Wenya; Vai, Mang I.; Rosa, Agostinho

2014-01-01

170

Alpha glucosidase inhibitors.  

PubMed

Alpha glucosidase inhibitors (AGIs) are a unique class of anti-diabetic drugs. Derived from bacteria, these oral drugs are enzyme inhibitors which do not have a pancreato -centred mechanism of action. Working to delay carbohydrate absorption in the gastrointestinal tract, they control postprandial hyperglycaemia and provide unquestioned cardiovascular benefit. Specially suited for a traditional Pakistani carbohydrate-rich diet, AGIs have been termed the 'untapped diamonds' of diabetology. The use of these oral antidiabetic drugs (OADs) that target pathophysiology in the early stages of type 2 diabetes, notably to reduce postprandial hyperglycaemia and hyperinsulinaemia will inevitably increase with time. This review describes the history of their development, mechanism of action, basic and clinical pharmacology, and suggests practical, evidence-based guidance for their optimal use. PMID:24864650

Kalra, Sanjay

2014-04-01

171

Alpha olefin oligomerization catalyst  

SciTech Connect

This patent describes a catalyst active for oligomerizing one or more oligomerizable alpha olefin monomers in a hydrocarbon solvent to produce linear olefin oligomers of from about 4 to about 20 carbon atoms. It comprises an organometallic compound wherein the metal thereof is selected from the group consisting of zinc, magnesium, and aluminum, in combination with the reaction mixture obtained by reacting in a hydrocarbon, a zirconium compound of the formula ZrX{sub n}Y{sub 4{minus}n} wherein X is a halogen, Y is selected from the group consisting of aryloxides, alkoxides, and carboxylates, and n ranges from 1 to 4, inclusive, and a basic salt of a carboxylic acid.

Fries, R.W.

1992-05-26

172

Microscopic cluster model of {alpha}+n, {alpha}+p, {alpha}+ {sup 3}He, and {alpha}+{alpha} elastic scattering from a realistic effective nuclear interaction  

SciTech Connect

An effective nucleon-nucleon interaction adapted to cluster-model calculations of collisions is derived from the realistic Argonne potential AV18 with the unitary correlation operator method. The unitary correlation is determined from the {alpha}+{alpha} elastic phase shifts calculated in a cluster approach by the generator coordinate method coupled with the microscopic R-matrix method. With this interaction, the elastic phase shifts for the {alpha}+n, {alpha}+p, and {alpha}+{sup 3}He collisions are calculated within the same model. Without further adjustment, a good agreement with experimental data is obtained with a small model space.

Dohet-Eraly, J.; Baye, D. [Physique Nucleaire et Physique Quantique, CP229, Universite Libre de Bruxelles (ULB), B-1050 Brussels (Belgium)

2011-07-15

173

Spatial correlation coefficient images for ultrasonic detection.  

PubMed

In ultrasonics, image formation and detection are generally based on signal amplitude. In this paper, we introduce correlation coefficient images as a signal-amplitude independent approach for image formation. The correlation coefficients are calculated between A-scans digitized at adjacent measurement positions. In these images, defects are revealed as regions of high or low correlation relative to the background correlations associated with noise. Correlation coefficient and C-scan images are shown to demonstrate flat-bottom-hole detection in a stainless steel annular ring and crack detection in an aluminum aircraft structure. PMID:17941390

Cepel, Raina; Ho, K C; Rinker, Brett A; Palmer, Donald D; Lerch, Terrence P; Neal, Steven P

2007-09-01

174

Statistical Methods with Varying Coefficient Models  

PubMed Central

The varying coefficient models are very important tool to explore the dynamic pattern in many scientific areas, such as economics, finance, politics, epidemiology, medical science, ecology and so on. They are natural extensions of classical parametric models with good interpretability and are becoming more and more popular in data analysis. Thanks to their flexibility and interpretability, in the past ten years, the varying coefficient models have experienced deep and exciting developments on methodological, theoretical and applied sides. This paper gives a selective overview on the major methodological and theoretical developments on the varying coefficient models.

Fan, Jianqing; Zhang, Wenyang

2008-01-01

175

On the emission coefficient of uranium plasmas.  

NASA Technical Reports Server (NTRS)

The emission coefficient for uranium plasmas (temperature: 8000 K) was measured for the wavelength range from 1200 to 6000 A. The results were compared to theoretical calculations and other measurements. Reasonable agreement between theoretical predictions and our measurements was found in the region from 1200 to 2000 A. Although it was difficult to make absolute comparisons among the different reported measurements, considerable disagreement was found for the higher wavelength region. A short discussion regarding the overall comparisons is given, and final suggestions are made as to the most appropriate emission coefficient values to be used in future design calculations. The absorption coefficient for the same wavelength interval is also reported.

Schneider, R. T.; Campbell, H. D.; Mack, J. M.

1973-01-01

176

Radon diffusion coefficients for residential concretes  

SciTech Connect

Radon gas diffusion through concrete can be a significant mechanism for radon entry into dwellings. Measurements of radon diffusion coefficients in the pores of residential concretes ranged from 2.1 x 10{sup {minus}8} m{sup 2} s{sup {minus}1} to 5.2 x 10{sup {minus}7} m{sup 2} s{sup {minus}1}. The pore diffusion coefficients generally increased with the water-cement ratio of the concrete and decreased with its density. A least-squares regression of the diffusion coefficients on concrete density gave an r value of -0.73. 16 refs., 2 figs., 3 tabs.

Rogers, V.C.; Nielson, K.K.; Holt, R.B. [Rogers and Associates Engineering Corp., Salt Lake City, UT (United States); Snoddy, R. [Acurex Environmental Corp., Research Triangle Park, NC (United States)

1994-09-01

177

Diffuse reflection coefficient of a stratified sea.  

PubMed

A differential equation of a Riccati type for the diffuse reflection coefficient of a stratified sea is proposed. For a homogeneous sea with arbitrary inherent optical properties this equation is solved analytically. For an inhomogeneous sea it is solved approximately for any arbitrary stratification. The resulting equation expresses the diffuse reflection coefficient of the sea through vertical profiles of absorption and backscattering coefficients, bottom albedo, and sea depth. The results of calculations with this equation are compared with Monte Carlo computations. It was found that the precision of this approach is in the range of 15%. PMID:18305694

Haltrin, V I

1999-02-20

178

Measurements of heat transfer coefficients and friction factors in passages rib-roughened on all walls  

SciTech Connect

A liquid crystal technique was used to measure heat transfer coefficients in twelve test sections with square and trapezoidal cross-sectional areas representing blade midchord cooling cavities in a modern gas turbine. Full-length ribs were configured on suction side as well as pressure side walls while half-length ribs were mounted on partition walls between adjacent cooling cavities. Ribs were in staggered arrangements with a nominal blockage ratio of 22% and an angle of attack to the mainstream flow, {alpha}, of 90 deg. Heat transfer measurements were performed on the roughened walls with full-length as well as half-length ribs. Nusselt numbers, friction factors, and thermal performances of all geometries are compared. The most important conclusion of this study is that the roughening of the partition walls enhances the heat transfer coefficients on those walls but, more importantly, enhances heat transfer coefficients on the primary walls considerably.

Taslim, M.E.; Li, T. [Northeastern Univ., Boston, MA (United States). Dept. of Mechanical Engineering; Spring, S.D. [GE Aircraft Engines, Lynn, MA (United States)

1998-07-01

179

Carcinogenic risk coefficients at environmental levels of radon exposures: A microdosimetric approach  

SciTech Connect

We report a microdosimetric-based evaluation of the effects of domestic exposure to radon. The risk coefficients obtained here are based on the microdosimetry of radon progeny alpha particles, on a function q(y) for in vivo radiogenic neoplasia, and on scaling A-bomb results (epidemiology + microdosimetry) to radon exposure. We do not use miner data, nor do we invoke such notions as quality factors, dose equivalent or equivalent dose. With basal cells as targets our estimated risk coefficients are in good agreement with the miner data, and thus a quality factor of about 20 (as suggested by ICRP 60) is not unreasonable. However, if we take as targets the secretory cells our risk coefficients are twice as large as those reported by BEIR-IV. The main uncertainty in these estimates remains the dosimetric model. 35 refs., 4 figs., 2 tabs.

Zaider, M. [Columbia Univ., New York, NY (United States); Varma, N. [Department of Energy, Washington, DC (United States)

1996-06-01

180

Probability density of the empirical wavelet coefficients of a noisy chaos  

NASA Astrophysics Data System (ADS)

We are interested in the random empirical wavelet coefficients of a noisy signal when this signal is a unidimensional or multidimensional chaos. More precisely we provide an expression of the conditional probability density of such coefficients, given a discrete observation grid. The noise is assumed to be described by a symmetric alpha-stable random variable. If the noise is a dynamic noise, then we present the exact expression of the probability density of each wavelet coefficient of the noisy signal. If we face a measurement noise, then the noise has a non-linear influence and we propose two approximations. The first one relies on a Taylor expansion whereas the second one, relying on an Edgeworth expansion, improves the first general Taylor approximation if the cumulants of the noise are defined. We give some illustrations of these theoretical results for the logistic map, the tent map and a multidimensional chaos, the Hénon map, disrupted by a Gaussian or a Cauchy noise.

Garcin, Matthieu; Guégan, Dominique

2014-05-01

181

Analysis of alpha3 GlyR single particle tracking in the cell membrane.  

PubMed

Single particle tracking (SPT) of transmembrane receptors in the plasma membrane often reveals heterogeneous diffusion. A thorough interpretation of the displacements requires an extensive analysis suited for discrimination of different motion types present in the data. Here the diffusion pattern of the homomeric alpha3-containing glycine receptor (GlyR) is analyzed in the membrane of HEK 293 cells. More specifically, the influence of the alpha3 RNA splice variants alpha3K and alpha3L on lateral membrane diffusion of the receptor is revealed in detail. Using a combination of ensemble and local SPT analysis, free and anomalous diffusion parameters are determined. The GlyR alpha3 free diffusion coefficient is found to be 0.13 +/- 0.01 microm2/s and both receptor variants display confined motion. The confinement probability level and residence time are significantly elevated for the alpha3L variant compared to the alpha3K variant. Furthermore, for the alpha3L GlyR, the presence of directed motion was also established, with a velocity matching that of saltatory vesicular transport. These findings reveal that alpha3 GlyRs are prone to different types of anomalous diffusion and reinforce the role of RNA splicing in determining lateral membrane trafficking. PMID:24316136

Notelaers, Kristof; Rocha, Susana; Paesen, Rik; Smisdom, Nick; De Clercq, Ben; Meier, Jochen C; Rigo, Jean-Michel; Hofkens, Johan; Ameloot, Marcel

2014-03-01

182

Genetics Home Reference: Alpha thalassemia  

MedlinePLUS

... HbH disease, or alpha thalassemia trait. The precise risk depends on how many alleles are missing and which combination of the HBA1 and HBA2 genes is affected. Where can I find information about diagnosis or management of alpha thalassemia? These resources address the diagnosis ...

183

Obtaining transport diffusion coefficients from self-diffusion coefficients in nanoporous adsorption systems  

NASA Astrophysics Data System (ADS)

In a continuation of the study of the adsorption and transport properties in a nanoporous adsorption system, transport diffusion coefficients are predicted from the self-diffusion coefficients using the Darken equation, modified for use in the adsorbed phase. We obtain self-diffusion coefficients using equilibrium molecular dynamics (MD) simulations. Adsorption equilibrium data are required in this modified form, which are obtained using grand canonical Monte Carlo (GCMC) simulations. We show that principal component regression provides an elegant and robust method to integrate the data available from the MD and GCMC simulations for the prediction of transport diffusivities. We investigate the effect of the adsorbed phase concentration, mole fraction and temperature on the transport diffusion coefficient thus predicted. We show that the self- and the transport diffusion coefficients decrease with increasing adsorbed phase concentration. We also show that the transport diffusion coefficients decrease with increasing methane mole fraction, in contrast to the behaviour of the self-diffusion coefficients.

Adhangale, Parag; Keffer, David J.

184

Damage Coefficients in Low Resistivity Silicon.  

National Technical Information Service (NTIS)

Electron and proton damage coefficients are determined for low resistivity silicon based on minority-carrier lifetime measurements on bulk material and diffusion length measurements on solar cells. Irradiations were performed on bulk samples and cells fab...

J. R. our S. Othmer K. Y. Chiu O. L. Curtis

1975-01-01

185

APRECOT - Analysis Program for Reactivity Coefficient Tests.  

National Technical Information Service (NTIS)

A computer program has been written which provides a rapid and convenient analysis route for fuel temperature coefficient of reactivity measurements, as carried out at Hinkley Point 'B' Power Station. This replaces the earlier, more tedious, iterative ana...

A. R. R. Telford

1979-01-01

186

Thermal Expansion Coefficient Determination by CBED.  

National Technical Information Service (NTIS)

Thermal expansion coefficients have been obtained for Al by measurements of HOLZ lines present in (114) convergent beam electron diffraction (CBED) patterns. These were in reasonable agreement with literature values. For materials with much lower expansio...

P. Angelini J. Bentley

1984-01-01

187

Determination of reaeration coefficients for Ohio streams  

USGS Publications Warehouse

The hydrocarbon-gas tracer technique was used to determine reaeration coefficients on 30 reaches of Ohio streams. The studies were done from September 1979 through August 1982 to determine the reaeration coefficients for the individual reaches and to develop general equation that could be used to estimate the coefficients. Multiple linear regression was used to determine relationships among the reaeration coefficients and physical stream characteristics. Four special equation based on the general equation were developed from various combinations of discharge, slope, width, depth, measured velocity, and estimated velocity. The standard errors of estimate for these equations ranged from 37 to 47 percent. The variables that resulted in the lowest standard error of estimate were discharge, slope, width, depth, and measured velocity. The most significant variables were depth and velocity.

Hren, Janet

1984-01-01

188

Trigonometric series with general monotone coefficients  

NASA Astrophysics Data System (ADS)

We study trigonometric series with general monotone coefficients. Convergence results in the different metrics are obtained. Also, we prove a Hardy-type result on the behavior of the series near the origin.

Tikhonov, S.

2007-02-01

189

Individual Activity Coefficients of Ionic Species.  

National Technical Information Service (NTIS)

The theoretical considerations which apply in particular for the temperature coefficient of the electric tension of the Pt-H2/H(+) electrode including those concerning the correction terms for the pressure of the hydrogen gas are first discussed, followed...

G. Milazzo I. P. Reyftman V. K. Sharma

1970-01-01

190

Low Grazing Angle Tarrain Backscattering Coefficient Generator.  

National Technical Information Service (NTIS)

A near-horizon probabilistic terrain backscatter coefficient generator is introduced, combining modified sea-state curves with Weibull-type probability density functions. A total of nine terrain type classifications (soils & rocks, trees, grasses, shrubs,...

W. N. O'Connor

1999-01-01

191

Heat transfer coefficient of cryotop during freezing.  

PubMed

Cryotop is an efficient vitrification method for cryopreservation of oocytes. It has been widely used owing to its simple operation and high freezing rate. Recently, the heat transfer performance of cryotop was studied by numerical simulation in several studies. However, the range of heat transfer coefficient in the simulation is uncertain. In this study, the heat transfer coefficient for cryotop during freezing process was analyzed. The cooling rates of 40 percent ethylene glycol (EG) droplet in cryotop during freezing were measured by ultra-fast measurement system and calculated by numerical simulation at different value of heat transfer coefficient. Compared with the results obtained by two methods, the range of the heat transfer coefficient necessary for the numerical simulation of cryotop was determined, which is between 9000 W/(m(2)·K) and 10000 W/(m (2)·K). PMID:23812315

Li, W J; Zhou, X L; Wang, H S; Liu, B L; Dai, J J

2013-01-01

192

New index functions for storing Gaunt coefficients  

NASA Astrophysics Data System (ADS)

Gaunt coefficients express angular momentum conservation rules. They are therefore required in the combination of atomic orbitals. In this case, the angular factors are spherical harmonics and the Gaunt coefficients appear when their products are linearized. The Gaunt coefficients may be pre-calculated and stored. This work describes new index functions for storing and retrieving the required Gaunt coefficients that are (almost) all nonzero. This strategy is closely related to that of Rasch and Yu, who have compared retrieval to that using recurrence relations and found it to be at least 20 times faster. Some improvements to their work will be found here and the index functions used are different. Only a few arithmetic operations are required to generate the index; therefore, its evaluation and handling takes a negligible time compared to its applications, notably molecular electronic integral evaluation.0

Pinchon, Didier; Hoggan, Philip E.

193

Second coefficient of viscosity in air  

NASA Technical Reports Server (NTRS)

Acoustic attenuation measurements in air were analyzed in order to estimate the second coefficient of viscosity. Data over a temperature range of 11 C to 50 C and at relative humidities between 6 percent and 91 percent were used. This analysis showed that the second coefficient of viscosity varied between 1900 and 20,000 times larger than the dynamic or first coefficient of viscosity over the temperature and humidity range of the data. In addition, the data showed that the molecular relaxation effects, which are responsible for the magnitude of the second coefficient of viscosity, place severe limits on the use of time-independent, thermodynamic equations of state. Compressible flows containing large streamwise velocity gradients, like shock waves, which cause significant changes in particle properties to occur during time intervals shorter than hundredths of seconds, must be modeled using dynamic equations of state. The dynamic model approach is described briefly.

Ash, Robert L.; Zuckerwar, Allan J.; Zheng, Zhonquan

1991-01-01

194

permeability coefficient in Darcy's filtration law  

NASA Astrophysics Data System (ADS)

Using the equation of living forces averaged over the volume of the filter and obtained from the Navier-Stokes equations of an incompressible fluid, an analytical formula for the permeability coefficient in the classical Darcy problem is derived to within the principal terms of the Poiseuille number. It is shown that the resulting permeability coefficient is inversely proportional to the square of the specific surface area and the dimensionless average dissipation rate of the kinetic fluid energy in the filter.

Bushlanov, V. P.; Bushlanov, I. V.; Sentyakova, E. N.

2013-07-01

195

Radon diffusion coefficients for aged residential concretes  

Microsoft Academic Search

This note reports radon gas pore diffusion coefficient measurements for residential concretes from Florida, ranging in age from 12 y to 45 y. The coefficients ranged from 1.5 x 10⁻⁷ m² s⁻¹ to 5.5 x 10⁻⁷ m² s⁻¹. On the average, these values are about a factor of 1.6 higher than average values previously reported for new residential concretes in

Vern C. Rogers; Kirk K. Nielson; Rodger B. Holt

1995-01-01

196

Radon diffusion coefficients for residential concretes  

Microsoft Academic Search

Radon gas diffusion through concrete can be a significant mechanism for radon entry into dwellings. Measurements of radon diffusion coefficients in the pores of residential concretes ranged from 2.1 x 10⁻⁸ m² s⁻¹ to 5.2 x 10⁻⁷ m² s⁻¹. The pore diffusion coefficients generally increased with the water-cement ratio of the concrete and decreased with its density. A least-squares regression

Vern C. Rogers; Kirk K. Nielson; Rodger B. Holt; Richard Snoddy

1994-01-01

197

WWW Database of Variable Star Fourier Coefficients  

NASA Astrophysics Data System (ADS)

Fourier coefficients are a valuable tool in the study of a wide variety of pulsating stars. In the case of RR Lyrae stars they, can be used to estimate various physical parameters, such as mass, luminosity, metallicity, and effective temperature. They are frequently used to discriminate between different pulsation modes for both RR Lyrae stars and Cepheids. Fourier coefficients have been published for stars based on many different photometric systems as well as for radial velocity measurements. With the release of coefficients from large-scale surveys and the availability of these data on the Internet, the number of Fourier coefficients available for study has significantly increased, and it is difficult to obtain all available data for individual stars or a given subset of stars. To assist researchers in obtaining and making use of Fourier coefficients, an on-line archive of published values of Fourier coefficients has been established. Users can search the database using a variety of tools, and the data sets extend beyond the Milky Way to include extragalactic variables. The archive is located at the Web site http://nitro9.earth.uni.edu/fourier/.

Morgan, Siobahn M.

2003-10-01

198

Electrophilic Nitration, Halogenation, Acylation, and Alkylation of Alpha, Alpha, Alpha-Trifluoromethoxybenzene,  

National Technical Information Service (NTIS)

Electrophilic nitration of alpha, a,a-trifluoromethoxybenzene gave 88-93% para and 12-7% ortho isomer with no meta isomer detected. The relative reactivity of alpha, a,a-trifluoromethoxybenzene compared to benzene (determined in competition experiments) w...

G. A. Olah T. Yamoto T. Hashimoto J. G. Shih N. Trivedi

1987-01-01

199

Survey of the alpha-Nucleon Interaction.  

National Technical Information Service (NTIS)

A survey of the alpha-nucleon interaction is made. The experimental work on angular distributions of differential scattering cross-sections and polarizations in proton-alpha and neutron-alpha scattering is described. The phenomenological approach which in...

S. Ali A. A. Z. Ahmad N. Ferdous

1984-01-01

200

Genetics Home Reference: Alpha-mannosidosis  

MedlinePLUS

... PubMed Recent literature OMIM Genetic disorder catalog Conditions > Alpha-mannosidosis On this page: Description Genetic changes Inheritance ... names Glossary definitions Reviewed May 2014 What is alpha-mannosidosis? Alpha-mannosidosis is a rare inherited disorder ...

201

OPERATION GREENHOUSE. Scientific Director's Report of Atomic Weapon Tests at Eniwetok, 1951. Annex 1.9. Air-Drop Instrumentation. Part 2. Teller-Alpha.  

National Technical Information Service (NTIS)

It was the purpose of the Teller-Alpha experiment to measure the coefficient alpha by means of detectors placed a long distance from the bomb. The detectors are photoelectric devices which respond to visible light produced in the air surrounding the bomb ...

H. E. Grier

1985-01-01

202

Alpha-particle spectrometer experiment  

NASA Technical Reports Server (NTRS)

Mapping the radon emanation of the moon was studied to find potential areas of high activity by detection of radon isotopes and their daughter products. It was felt that based on observation of regions overflown by Apollo spacecraft and within the field of view of the alpha-particle spectrometer, a radon map could be constructed, identifying and locating lunar areas of outgassing. The basic theory of radon migration from natural concentrations of uranium and thorium is discussed in terms of radon decay and the production of alpha particles. The preliminary analysis of the results indicates no significant alpha emission.

Gorenstein, P.; Bjorkholm, P.

1972-01-01

203

ALPHA, DIMENSION-FREE, AND MODEL-BASED INTERNAL CONSISTENCY RELIABILITY  

Microsoft Academic Search

Sijtsma (in press) has ably critiqued the unfortunate ascendance of coefficient alpha as the almost universal and sole estimator of the somewhat vague population concept of internal con- sistency. Among several recommendations, he suggests to report the greatest lower bound, here denoted ?glb, as a measure of internal consistency reliability, and the explained common vari- ance (ECV) based on minimum

PETER M. BENTLER

2008-01-01

204

Hidden messages in heavy-tails: DCT-domain watermark detection using alpha-stable models  

Microsoft Academic Search

This paper addresses issues that arise in copyright protection systems of digital images, which employ blind watermark verification structures in the discrete cosine transform (DCT) domain. First, we observe that statistical distributions with heavy algebraic tails, such as the alpha-stable family, are in many cases more accurate modeling tools for the DCT coefficients of JPEG-analyzed images than families with exponential

Alexia Briassouli; Panagiotis Tsakalides; Athanasios Stouraitis

2005-01-01

205

Grafting of a reactive siloxane onto an alpha-olefin in the melt phase  

Microsoft Academic Search

This dissertation presents the outcomes of a study undertaken to graft a reactive siloxane onto an alpha-olefin in the melt phase with the objective of conducting grafting and sequentially making a film of low coefficient of friction in a twin screw extruder. The areas of focus of the research were (1) design of experiments, (2) batch kinetic study, (3) twin

Solomon Bekele

1999-01-01

206

Comparison of field-measured radon diffusion coefficients with laboratory-measured coefficients  

Microsoft Academic Search

Experiments were conducted to compare radon diffusion coefficients determined for 0.1-m depths of soils by a steady-state method in the laboratory and diffusion coefficients evaluated from radon fluxes through several-fold greater depths of the same soils covering uranium-mill tailings. The coefficients referred to diffusion in the total pore volume of the soils and are equivalent to values for the quantity,

E. A. Lepel; W. B. Silker; V. W. Thomas; D. R. Kalkwarf

1983-01-01

207

SMMA Alpha Spectrum Deconvolution Code.  

National Technical Information Service (NTIS)

We performed a computer code ''SMMA'' able to deconvoluate routinely alpha spectrometry spectrum including up to seven pics groups. The tailing is carried out by using homographic and exponential functions. (ERA citation 09:035869)

F. Amoudry

1983-01-01

208

Alpha Magnetic Spectrometer (AMS) Overview  

NASA Video Gallery

The Alpha Magnetic Spectrometer (AMS) is flying to the station on STS-134. The AMS experiment is a state-of-the-art particle physics detector being operated by an international team composed of 60 ...

209

Long-range alpha detection  

SciTech Connect

The detection and measurement of alpha contamination is not an easy task. An alpha particle`s characteristic high charge and large mass make it highly interactive with surrounding matter. The particle is often absorbed before its presence can be sensed with a detector. Los Alamos National Laboratory has studied this problem and has developed an improved process to detect alpha-emitting contaminants. The process is called long-range alpha detection (LRAD). The LRAD process focuses on the collection and measurement of ions created as a result of an alpha particle`s interaction with air. With only about 35 eV necessary to create an ion pair, a typical 5-MeV alpha particle, upon emission from its maternal nucleus, creates about 150,000 pairs of charged particles. In air these charged particles take several seconds to locate a mate and become electrically neutral. During this time, ions can be pulled away from the source, collected, and measured. Ions can be motivated to a collection device by using an electric field or by moving the air mass in which the ions are located. The collected charges create a small but discrete current that can give some useful information about the alpha-emitting source. In this article, two commercially available applications of the LRADS technology will be discussed. One of these, a device used primarily for pipe monitoring, is from BNFL Instruments, Inc. The other is a monitoring box of sorts from Eberline that will produce an alpha measurement on anything that is placed in the box.

Kasper, K.

1998-12-01

210

Self-diffusion coefficients of expanded rubidium  

NASA Astrophysics Data System (ADS)

The second-order and fourth-order frequency sum rules of the velocity autocorrelation function (VACF) of Rb have been evaluated for six thermodynamic states along the liquid - vapour coexistence curve by using the Ashcroft pseudopotential and corresponding pair distribution function obtained by molecular dynamics (MD) simulation. These sum rules and a model for the self-diffusion coefficient have been used to study the time evolution of the VACF and self-diffusion coefficients. The results obtained have been compared with MD simulation data. It is found that our model provides the first semiquantitative explanation for the density and temperature dependences of the VACF and self-diffusion coefficients of expanded Rb.

Sharma, Saroj K.; Tankeshwar, K.

1996-12-01

211

Temperature coefficients of multijunction solar cells  

NASA Technical Reports Server (NTRS)

Temperature coefficients measured in solar simulators with those measured under AM0 solar illumination are compared to illustrate the challenges in making these measurements. It is shown that simulator measurements of the short-circuit current (delta Jsc/delta T) are inaccurate due to the mismatch between the solar spectrum and the simulators at the bandgaps of the solar cells. Especially susceptible to error is the delta Jsc/delta T of cells which are components in monolithic multijunction solar cells, such as GaAs filtered by 1.93-eV AlGaAs, which has an AM0 coefficient of 6.82 micro-A/sq cm/deg C, compared to a Xenon simulator coefficient of 22.2 micro-A/sq cm/deg C.

Virshup, G. F.; Chung, B.-C.; Ladle Ristow, M.; Kuryla, M. S.; Brinker, D.

1990-01-01

212

Radial diffusion coefficients in the outer heliosphere  

NASA Astrophysics Data System (ADS)

When cosmic ray streaming in the heliosphere is negligible, the basic onedimensional transport model gives a simple approximation for the diffusion coefficient of cosmic ray particles, ~Zrr=CVSW/gr, where C is the Compton-Gettiing factor, VSW is the solar wind velocity and gr is the radial intensity gradients. In a separate paper at this conference we made detailed measurement of radial intensity gradients in the outer heliosphere from the combined data set observed over the solar activity minima of 1977/1997(qA>0). Using these detailed gradients and onedimensional transport model we calculate the diffusion coefficients in the outerheliosphere. These diffusion coefficients are compared with those of 1987 to also search for drift effects as manifested over two successive solar minima periods

Fujii, Z.; McDonald, F. B.; Moraal, H.

2001-08-01

213

Technical Note: The horizontal scale-dependence of the cloud overlap parameter alpha  

NASA Astrophysics Data System (ADS)

The cloud overlap parameter alpha relates the combined cloud fraction between two altitude levels in a grid box to the cloud fraction as derived under the maximum and random overlap assumptions. In a number of published studies in this and other journals it is found that alpha tends to increase with increasing scale. In this technical note, we investigate this analytically by considering what happens to alpha when two grid boxes are merged to give a grid box with twice the area. Assuming that alpha depends only on scale then, between any two fixed altitudes, there will be a linear relationship between the values of alpha at the two scales. We illustrate this by finding the relationship when cloud cover fractions are assumed to be uniformly distributed, but with varying degrees of horizontal and vertical correlation. Based on this, we conclude that alpha increases with scale if its value is less than the vertical correlation coefficient in cloud fraction between the two altitude levels. This occurs when the cloud are deeper than would be expected at random (i.e. for exponentially distributed cloud depths). However, the degree of scale-dependence is controlled by the horizontal correlation coefficient in the cloud fraction between adjacent grid boxes, being greatest when this correlation is zero. Trivially, there is no scale-dependence when this correlation is one. The observed, generally strong, scale-dependence would thus indicate that the horizontal correlation is small.

Astin, I.; Di Girolamo, L.

2014-04-01

214

Solubilization and partial characterization of rat epididymal delta 4-steroid 5 alpha-reductase (cholestenone 5 alpha-reductase).  

PubMed Central

Epididymal delta 4-steroid 5 alpha-reductase (cholestenone 5 alpha-reductase), the enzyme that catalyses the conversion of testosterone into the biologically active metabolite dihydrotestosterone (17 beta-hydroxy-5 alpha-androstan-3-one), is a membrane-bound enzyme found in both nuclear and microsomal subcellular fractions. In order to characterize epididymal delta 4-steroid 5 alpha-reductase, it was first necessary to solubilize the enzymic activity. Of the various treatments tested, a combination of 0.5% (w/v) Lubrol WX, 0.1 M-sodium citrate and 0.1 M-KCl maintained enzymic activity at control values and solubilized 66% of total epididymal delta 4-steroid 5 alpha-reductase activity in an active and stable form. The sedimentation coefficient of solubilized delta 4-steroid 5 alpha-reductase, as determined in continuous sucrose density gradients, was greater for the microsomal than for the nuclear enzyme (11.6S compared with 10.1S). Although the apparent Km values of the enzyme for testosterone were similar in nuclear and microsomal subcellular fractions (range 1.75 x 10(-7) - 4.52 x 10(-7)M), the apparent Km of the enzyme for NADPH was about 30-fold greater for the microsomal enzyme than for the nuclear enzyme. The apparent Km of the enzyme for either substrate was not significantly altered after solubilization. The relative capacity of steroids to inhibit the enzymic activity, the pH optima and the effects of Ca2+ and Mg2+ were similar for membrane-bound and solubilized delta 4-steroid 5 alpha-reductase in both the nuclear and the microsomal fractions. The results reported demonstrate that epididymal delta 4-steroid 5 alpha-reductase can be solubilized in an active and stable form with no significant changes in the kinetic characteristics of the enzyme after solubilization; furthermore, kinetic and molecular-size differences observed for the nuclear and the microsomal forms of the enzyme suggest that there may exist at least two forms of epididymal delta 4-steroid 5 alpha-reductase.

Scheer, H; Robaire, B

1983-01-01

215

NEW SCALING FOR THE ALPHA EFFECT IN SLOWLY ROTATING TURBULENCE  

SciTech Connect

Using simulations of slowly rotating stratified turbulence, we show that the {alpha} effect responsible for the generation of astrophysical magnetic fields is proportional to the logarithmic gradient of kinetic energy density rather than that of momentum, as was previously thought. This result is in agreement with a new analytic theory developed in this paper for large Reynolds numbers and slow rotation. Thus, the contribution of density stratification is less important than that of turbulent velocity. The {alpha} effect and other turbulent transport coefficients are determined by means of the test-field method. In addition to forced turbulence, we also investigate supernova-driven turbulence and stellar convection. In some cases (intermediate rotation rate for forced turbulence, convection with intermediate temperature stratification, and supernova-driven turbulence), we find that the contribution of density stratification might be even less important than suggested by the analytic theory.

Brandenburg, A.; Gressel, O.; Kaepylae, P. J.; Kleeorin, N.; Rogachevskii, I. [Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-10691 Stockholm (Sweden)] [Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-10691 Stockholm (Sweden); Mantere, M. J. [Department of Physics, University of Helsinki, Gustaf Haellstroemin katu 2a, P.O. Box 64, FI-00064 Helsinki (Finland)] [Department of Physics, University of Helsinki, Gustaf Haellstroemin katu 2a, P.O. Box 64, FI-00064 Helsinki (Finland)

2013-01-10

216

Asymptotics of loop quantum gravity fusion coefficients  

NASA Astrophysics Data System (ADS)

The fusion coefficients from SO(3) to SO(4) play a key role in the definition of spin foam models for the dynamics in loop quantum gravity. In this paper we give a simple analytic formula of the Engle-Pereira-Rovelli-Livine fusion coefficients. We study the large spin asymptotics and show that they map SO(3) semiclassical intertwiners into SU(2)L × SU(2)R semiclassical intertwiners. This non-trivial property opens the possibility for an analysis of the semiclassical behavior of the model.

Alesci, Emanuele; Bianchi, Eugenio; Magliaro, Elena; Perini, Claudio

2010-05-01

217

Huge Seebeck coefficients in nonaqueous electrolytes  

NASA Astrophysics Data System (ADS)

The Seebeck coefficients of the nonaqueous electrolytes tetrabutylammonium nitrate, tetraoctylphosphonium bromide, and tetradodecylammonium nitrate in 1-octanol, 1-dodecanol, and ethylene-glycol are measured in a temperature range from T = 30 °C to T = 45 °C. The Seebeck coefficient is generally of the order of a few hundreds of microvolts per Kelvin for aqueous solution of inorganic ions. Here we report huge values of 7 mV/K at 0.1 M concentration for tetrabutylammonium nitrate in 1-dodecanol. These striking results open the question of unexpectedly large kosmotrope or ``structure making'' effects of tetraalkylammonium ions on the structure of alcohols.

Bonetti, M.; Nakamae, S.; Roger, M.; Guenoun, P.

2011-03-01

218

Second virial coefficients of dipolar hard spheres  

NASA Astrophysics Data System (ADS)

An asymptotic formula is reported for the second virial coefficient B2 of a dipolar hard-sphere (DHS) fluid, in zero external field, for strongly coupled dipolar interactions. This simple formula, together with the one for the weak-coupling B2, provides an accurate prediction of the second virial coefficient for a wide range of dipole moments, including those that are experimentally accessible in magnetite ferrofluids. The weak-coupling B2 also yields an estimate of the magnetic moment minimally needed for isotropic gas-liquid phase-separation, if any, in the DHS fluid.

Philipse, Albert P.; Kuipers, Bonny W. M.

2010-08-01

219

Coefficient of restitution for viscoelastic materials  

NASA Astrophysics Data System (ADS)

An analytical expression of the coefficient of restitution for viscoelastic materials is derived for the viscous-dominant case, such as collisions of a polymeric melt. The recently proposed normal impact force model between two colliding viscoelastic droplets is employed. A perturbation method is applied to analytically solve the nonlinear differential equation of deformation caused by the other droplet. By combining the forward collision and the inverse collision, we can get an analytical expression for the coefficient of restitution, which can also be used to further analyze other properties related with the viscoelasticity.

Kim, Sangrak

2014-02-01

220

Tumour necrosis factor-alpha and interleukin-1 and -6 in fibrocystic breast disease.  

PubMed

The risk of developing breast cancer is higher in women presenting gross cystic disease (cysts > 3 mm in diameter) of the breast with intracystic K+/Na+ > 3 as compared with K+/Na+ < 3. The present study reports the levels of tumour necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), and interleukin-6 (IL-6) in the breast cyst fluid of women with gross cystic disease and analyses the relationship between the intracystic concentration of these cytokines, sex steroid hormones, and the K+/Na+ ratio. The concentration of these cytokines, estradiol, testosterone, dehydroepiandrosterone sulfate (DHEA-S), and 17-OH-progesterone were determined in the breast cyst fluid of 54 women with gross cystic disease. No significant differences were found in the cystic levels of IL-1 between cysts with intracystic K+/Na+ < 3 and > 3. However, in cysts with intracystic K+/Na+ > 3 we found a lower concentration of IL-6 and TNF-alpha than in those with intracystic K+/Na+ < 3. Stepwise multiple linear regression analysis demonstrated that the concentration of IL-6 in breast cyst fluid was predicted statistically by a negative regression coefficient for the concentration of estradiol and DHEA-S, and by a positive regression coefficient for the concentration of TNF-alpha. The concentration of TNF-alpha in breast cyst fluid was predicted statistically by a positive regression coefficient for the concentration of IL-6, and by a negative regression coefficient for the concentration of estradiol. No candidate variable was included in the model to predict concentrations of IL-1 in breast cyst fluid. Our results indicate that IL-6 and TNF-alpha could have a local 'protector' role in gross cystic disease, and that they could be used as a marker to identify cyst type. PMID:10424406

Herruzo, A; Castilla, J A; Ramírez, A; Marcos, C; Menjón, S

1999-03-01

221

Dependence of Seebeck coefficient on a load resistance and energy conversion efficiency in a thermoelectric composite  

SciTech Connect

The thermo-emf {delta}V and current {delta}I generated by imposing the alternating temperature gradients (ATG) at a period of T and the steady temperature gradient (STG) on a thermoelectric (TE) composite were measured as a function of t, where t is the lapsed time and T was varied from 60 to or {infinity} s. The STG and ATG were produced by imposing steadily and alternatively a source voltage V in the range from 1.0 to 4.0 V on two Peltier modules sandwiching a composite. {delta}T, {delta}V, {delta}I and V{sub P} oscillate at a period T and their waveforms vary significantly with a change of T, where {delta}V and V{sub P} are the voltage drops in a load resistance R{sub L} and in resistance R{sub P} of two modules. The resultant Seebeck coefficient |{alpha}| = |{delta}V|/{delta}T of a composite under the STG was found to be expressed as |{alpha}| = |{alpha}{sub 0}|(1 - R{sub comp}/R{sub T}), where R{sub T} is the total resistance of a circuit for measuring the output signals and R{sub comp} is the resistance of a composite. The effective generating power {delta}W{sub eff} has a local maximum at T = 960 s for the p-type composite and at T = 480 s for the n-type one. The maximum energy conversion efficiency {eta} of the p- and n-type composites under the ATG produced by imposing a voltage of 4.0 V at an optimum period were 0.22 and 0.23% at {delta}T{sub eff} = 50 K, respectively, which are 42 and 43% higher than those at {delta}T = 42 K under the STG. These maximum {eta} for a TE composite sandwiched between two Peltier modules, were found to be expressed theoretically in terms of R{sub P}, R{sub T}, R{sub L}, {alpha}{sub P} and {alpha}, where {alpha}{sub P} and {alpha} are the resultant Seebeck coefficients of Peltier modules and a TE composite.

Yamashita, Osamu [Materials Science Co. Ltd., 5-5-44 Minamikasugaoka, Ibaraki, Osaka 567-0046 (Japan)], E-mail: yamashio567@yahoo.co.jp; Odahara, Hirotaka [Advanced Materials Co. Ltd., 4-6-10 Kizuri, Higashiosaka, Osaka 577-0827 (Japan); Ochi, Takahiro; Satou, Kouji [Faculty of Engineering, Ehime University, Bunkyocho, Matsuyama 790-8577 (Japan)

2007-10-02

222

Zernike aberration coefficients transformed to and from Fourier series coefficients for wavefront representation  

Microsoft Academic Search

The set of Fourier series is discussed following some discussion of Zernike polynomials. Fourier transforms of Zernike polynomials are derived that allow for relating Fourier series expansion coefficients to Zernike polynomial expansion coefficients. With iterative Fourier reconstruction, Zernike representations of wavefront aberrations can easily be obtained from wavefront derivative measurements.

Guang-Ming Dai

2006-01-01

223

Zernike aberration coefficients transformed to and from Fourier series coefficients for wavefront representation.  

PubMed

The set of Fourier series is discussed following some discussion of Zernike polynomials. Fourier transforms of Zernike polynomials are derived that allow for relating Fourier series expansion coefficients to Zernike polynomial expansion coefficients. With iterative Fourier reconstruction, Zernike representations of wavefront aberrations can easily be obtained from wavefront derivative measurements. PMID:16496900

Dai, Guang-Ming

2006-02-15

224

Prediction of octanol?water partition coefficients, Henry coefficients and water solubilities using UNIFAC  

Microsoft Academic Search

Octanol\\/water partition coefficients, Henry coefficients and water solubilities can serve as basic physicochemical parameters for estimating the effects to the environment which can arise from potentially hazardous substances. We discuss the application of the UNIFAC method, which allows the prediction of these values on the basis of molecular structure. The UNIFAC method has the advantage over other models that the

G. Wienke; J. Gmehling

1998-01-01

225

Lattice Dynamics of Icosahedral {alpha}-Boron under Pressure  

SciTech Connect

The Raman spectrum of icosahedral {alpha}-boron presents a very sharp peak at 525cm{sup -1} that was consistently rejected from the lattice modes but is still unexplained. New Raman scattering experiments under pressure are compared with {bold {ital ab initio}} lattice dynamics calculations. The very good agreement of the mode frequencies and their pressure coefficients yields unambiguous assignment of all observed features, including the 525cm{sup -1} line which is a highly harmonic librational mode of the icosahedron and mainly involves bond bending. This mode is also identified in the Raman spectrum of other icosahedral boron-rich solids. {copyright} {ital 1997} {ital The American Physical Society}

Vast, N.; Zerah, G. [CEA--Commissariat a l`Energie Atomique, CELV, 94195 Villeneuve-Saint-Georges (France)] [CEA--Commissariat a l`Energie Atomique, CELV, 94195 Villeneuve-Saint-Georges (France); Baroni, S. [CECAM--Centre Europeen de Calcul Atomique et Moleculaire, ENS-Lyon, 46 Allee d`Italie, 69007 Lyon (France)] [CECAM--Centre Europeen de Calcul Atomique et Moleculaire, ENS-Lyon, 46 Allee d`Italie, 69007 Lyon (France); Baroni, S. [SISSA--Scuola Internazionale Superiore di Studi Avanzati, Via Beirut 2-4, 34014 Trieste (Italy)] [SISSA--Scuola Internazionale Superiore di Studi Avanzati, Via Beirut 2-4, 34014 Trieste (Italy); Besson, J.M.; Polian, A.; Chervin, J.C. [Physique des Milieux Condenses, URA 782, CNRS, Universite Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris (France)] [Physique des Milieux Condenses, URA 782, CNRS, Universite Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris (France); Grimsditch, M. [Argonne National Laboratories, Argonne, Illinois 60439 (United States)] [Argonne National Laboratories, Argonne, Illinois 60439 (United States)

1997-01-01

226

Zernike coefficients of a scaled pupil.  

PubMed

By expressing a scaled Zernike radial polynomial as a linear combination of the unscaled radial polynomials, we give a simple derivation for determining the Zernike coefficients of an aberration function of a scaled pupil in terms of their values for a corresponding unscaled pupil. PMID:20885474

Mahajan, Virendra N

2010-10-01

227

Zernike coefficients of a scaled pupil  

SciTech Connect

By expressing a scaled Zernike radial polynomial as a linear combination of the unscaled radial polynomials, we give a simple derivation for determining the Zernike coefficients of an aberration function of a scaled pupil in terms of their values for a corresponding unscaled pupil.

Mahajan, Virendra N.

2010-10-01

228

Molecular Diffusion Coefficients: Experimental Determination and Demonstration.  

ERIC Educational Resources Information Center

Presented are laboratory methods which allow the demonstration and determination of the diffusion coefficients of compounds ranging in size from water to small proteins. Included are the procedures involving the use of a spectrometer, UV cell, triterated agar, and oxygen diffusion. Results including quantification are described. (CW)

Fate, Gwendolyn; Lynn, David G.

1990-01-01

229

Uses and Misuses of the Correlation Coefficient.  

ERIC Educational Resources Information Center

The purpose of this paper is to provide an in-depth critical analysis of the use and misuse of correlation coefficients. Various analytical and interpretational misconceptions are reviewed, beginning with the egregious assumption that correlational statistics may be useful in inferring causality. Additional misconceptions, stemming from…

Onwuegbuzie, Anthony J.; Daniel, Larry G.

230

A Primer on Partial Correlation Coefficients.  

ERIC Educational Resources Information Center

Part and partial correlation coefficients are used to measure the strength of a relationship between a dependent variable and an independent variable while controlling for one or more other variables. The present paper discusses the uses and limitations of partial correlations and presents a small heuristic data set to illustrate the discussion.…

Waliczek, Tina M.

231

Coefficient Omega Bootstrap Confidence Intervals: Nonnormal Distributions  

ERIC Educational Resources Information Center

The performance of the normal theory bootstrap (NTB), the percentile bootstrap (PB), and the bias-corrected and accelerated (BCa) bootstrap confidence intervals (CIs) for coefficient omega was assessed through a Monte Carlo simulation under conditions not previously investigated. Of particular interests were nonnormal Likert-type and binary items.…

Padilla, Miguel A.; Divers, Jasmin

2013-01-01

232

When Should Epidemiologic Regressions Use Random Coefficients?  

Microsoft Academic Search

SUMMARY. Regression models with random coefficients arise naturally in both frequentist and Bayesian approaches to estimation problems. They are becoming widely available in standard computer packages under the headings of generalized linear mixed models, hierarchical models, and multilevel models. I here argue that such models offer a more scientifically defensible framework for epidemiologic analysis than the fixed-effects models now prevalent

Sander Greenland

2000-01-01

233

Calculation of the Anisotropic Diffusion Coefficient  

Microsoft Academic Search

The one-group anisotropic diffusion coefficient is calculated for slab and square lattice cells with use made of Benoist's formula. In utilizing the integral transport theory, only several collisions suffered by a neutron have hitherto been considered. In this paper, we adopt the integral theory and take into consideration the effect of an infinite number of collisions suffered by a neutron,

Toshikazu TAKEDA; Tamotsu SEKIYA

1972-01-01

234

Computing Tables for the Tetrachoric Correlation Coefficient  

Microsoft Academic Search

In 1933, Chesire, Saffir, and Thurstone published their Computing Diagrams for the Tetrachoric Correlation Coefficient. Since then there have been few developments to aid the practitioner in a rapid and more accurate calculation of the tetrachoric correlation. The present study describes a set of tables for ease in determining tetrachoric correlations. Entries are provided for all X variable dichotomies and

James Zalinski; Norman M. Abrahams; Edward Alf

1979-01-01

235

Rational Roots of Polynomials with Integer Coefficients  

ERIC Educational Resources Information Center

In this note the authors investigate ways to shorten the amount of work involved in using the Rational Roots Theorem to find the rational roots of a polynomial with integral coefficients. The first result is a proof of a fact that we had long suspected, but were never able to find the statement of in any of the college algebra textbooks we had…

Combs, Randel; Walls, Gary L.

2004-01-01

236

Double-smoothing for varying coefficient models  

Microsoft Academic Search

Moderation analyses are widely used in biomedical and psychosocial research to investigate differential treatment effects, with moderators frequently identified through testing the significance of the interaction between the predictor and the potential moderator under strong parametric assumptions. Without imposing any parametric forms on how the moderators may affect the relationship between predictors and responses, varying coefficient models address this fundamental

Wan Tang; Guoxin Zuo; Hua He

2011-01-01

237

The effective diffusion coefficient for porous rubble  

Microsoft Academic Search

Each waste package in the proposed Yucca Mountain repository is to be separated from surrounded unsaturated rock by a 2-cm air gap annulus. However, if the annulus becomes filled with rock and rubble, there can exist pathways for diffusive release of radionuclides through pore liquid, even if the repository remains unsaturated. The effective diffusion coefficient for radionuclide release through pore

M. M. Sadeghi; W. W.-L. Lee; T. H. Pigford; P. L. Chambre

1990-01-01

238

Computer programs for the concordance correlation coefficient.  

PubMed

The CCC macro is presented for computation of the concordance correlation coefficient (CCC), a common measure of reproducibility. The macro has been produced in both SAS and R, and a detailed presentation of the macro input and output for the SAS program is included. The macro provides estimation of three versions of the CCC, as presented by Lin [L.I.-K. Lin, A concordance correlation coefficient to evaluate reproducibility, Biometrics 45 (1989) 255-268], Barnhart et al. [H.X. Barnhart, J.L. Haber, J.L. Song, Overall concordance correlation coefficient for evaluating agreement among multiple observers, Biometrics 58 (2002) 1020-1027], and Williamson et al. [J.M. Williamson, S.B. Crawford, H.M. Lin, Resampling dependent concordance correlation coefficients, J. Biopharm. Stat. 17 (2007) 685-696]. It also provides bootstrap confidence intervals for the CCC, as well as for the difference in CCCs for both independent and dependent samples. The macro is designed for balanced data only. Detailed explanation of the involved computations and macro variable definitions are provided in the text. Two biomedical examples are included to illustrate that the macro can be easily implemented. PMID:17709153

Crawford, Sara B; Kosinski, Andrzej S; Lin, Hung-Mo; Williamson, John M; Barnhart, Huiman X

2007-10-01

239

Estimation of Van der Waals Broadening Coefficients  

Microsoft Academic Search

e N.N. Semenov Institute of Chemical Physics RAS, Kosigina Street 4, Moscow 117992, Russia Abstract. Van der Waals broadening coefficients for numerous spectral transitions and radiator- perturber pairs are estimated by semi-empirical methods. The results are verified by ab initio electronic structure calculations and available experimental data. At the same time this allows to establish the range of applicability of

V. A. Astapenko; S. Ya

2010-01-01

240

Mel Frequency Cepstral Coefficients for Music Modeling  

Microsoft Academic Search

We examine in some detail Mel Frequency Cepstral Coefficients (MFCCs) - the dominant features used for speech recognition - and investigate their applicability to modeling music. In particular, we examine two of the main assumptions of the process of forming MFCCs: the use of the Mel frequency scale to model the spectra; and the use of the Discrete Cosine Transform

Beth Logan

2000-01-01

241

Particle drag coefficients in turbulent fluids  

Microsoft Academic Search

An accurate estimation of particle settling velocities, and\\/or of particle drag coefficients, is required for modelling purposes in many industrially important multiphase processes involving the suspension of millimetre and sub-millimetre size particles in a liquid phase. It is known that the settling velocity of particles in a turbulent fluid may be significantly different from that in the still fluid, depending

A. Brucato; F. Grisafi; G. Montante

1998-01-01

242

Tire-Road Friction-Coefficient Estimation  

Microsoft Academic Search

Tire-road forces are crucial in vehicle dynamics and control because they are the only forces that a vehicle experiences from the ground. These forces significantly affect the lateral, longitudinal, yaw, and roll behavior of the vehicle. The maximum force that a tire can supply is determined by the maximum value of the tire-road friction coefficient for a given normal vertical

Rajesh Rajamani; Neng Piyabongkarn; Jae Lew; Kyongsu Yi; Gridsada Phanomchoeng

2010-01-01

243

On Not Interpreting Coefficients: Comment on Holt.  

ERIC Educational Resources Information Center

A recent recommendation by Holt (EJ 200 576) that coefficients resulting from estimating log-linear and similar models should not be interpreted is argued to be based on lack of clarity about the substantive and theoretical importance of the choice between dummy and effect coding for categorical variables. (Author/GDC)

Wilson, Thomas P.

1979-01-01

244

Measuring correlations between non-stationary series with DCCA coefficient  

NASA Astrophysics Data System (ADS)

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

Kristoufek, Ladislav

2014-05-01

245

Temperature dependence of the evaporation coefficient of water in air and nitrogen under atmospheric pressure: study in water droplets.  

PubMed

The evaporation coefficients of water in air and nitrogen were found as a function of temperature by studying the evaporation of a pure water droplet. The droplet was levitated in an electrodynamic trap placed in a climatic chamber maintaining atmospheric pressure. Droplet radius evolution and evaporation dynamics were studied with high precision by analyzing the angle-resolved light scattering Mie interference patterns. A model of quasi-stationary droplet evolution accounting for the kinetic effects near the droplet surface was applied. In particular, the effect of thermal effusion (a short-range analogue of thermal diffusion) was discussed and accounted for. The evaporation coefficient alpha in air and in nitrogen were found to be equal. The alpha was found to decrease from approximately 0.18 to approximately 0.13 for the temperature range from 273.1 to 293.1 K and follow the trend given by the Arrhenius formula. The agreement with condensation coefficient values obtained with an essentially different method by Li et al. [Li, Y.; Davidovits, P.; Shi, Q.; Jayne, J.; Kolb, C.; Worsnop, D. J. Phys. Chem. A. 2001, 105, 10627] was found to be excellent. The comparison of experimental conditions used in both methods revealed no dependence of the evaporation/condensation coefficient on the droplet charge nor the ambient gas pressure within the experimental parameters range. The average value of the thermal accommodation coefficient over the same temperature range was found to be 1 +/- 0.05. PMID:18491849

Zientara, M; Jakubczyk, D; Kolwas, K; Kolwas, M

2008-06-12

246

Pyroelectric coefficient manipulation in doped TGS crystals  

NASA Astrophysics Data System (ADS)

Pure and L-alanine doped Triglycine sulphate (TGS) crystals were grown in paraelectric phase (˜52 °C). Doped crystals show unequal growth rates along the ferroelectric axis. Pure TGS crystals show peculiar dielectric behavior in the ferroelectric phase, after crossing up and down the Curie point in two successive runs between room temperature and 80 °C. Much higher and unstable permittivity was found returning in the ferroelectric phase. At constant temperature (35 °C), permittivity follows a relaxation process, characterized by two relaxation times. L-Alanine doped TGS crystal shows more than one order of magnitude smaller permittivity and dielectric losses. Internal bias field of ˜1 kV/cm, induced by the dopant, made the crystal almost monodomain and pined polarization in one direction. Pyroelectric coefficient measurements were performed at constant heating rate of the samples, using a computer controlled He cryostat and Keithley 6517 electrometer. The temperature dependence of P + polarization component, obtained by computer integration of the pyroelectric coefficient, was measured on a large temperature interval (-20/+80 °C). Pyroelectric coefficient of the doped samples was also measured by the same procedure, using a dc bias electric field, pointing in the opposite direction to the pined polarization. The polarization could be reversed, on the whole temperature range, by dc fields higher than bias or coercive field. Surprisingly, for the first time, the pyroelectric coefficient ( p) was found constant on quite large temperature intervals. Doped TGS crystals show much smaller values of permittivity ?r versus the pure one and consequently, get higher figure of merit M = p/ ?r. The pyroelectric coefficient of this material can be tailored to become constant on a defined temperature range, under a dc field control. This characteristic makes this material valuable to be used as pyroelectric material for IR devices.

Alexandru, H. V.; Berbecaru, C.; Ion, L.; Dutu, A.; Ion, F.; Pintilie, L.; Radulescu, R. C.

2006-10-01

247

Characterization of alpha-cordierite glass-ceramics from fly ash.  

PubMed

Batches of alpha-cordierite glass-ceramics, designated as GC-I and GC-II, containing 68 and 64 wt.% fly ash, respectively, were crystallized in the temperature range of 1125-1320 degrees C. The XRD (X-ray powder diffractometer) of the glass-ceramics show that alpha-cordierite became the dominant phase in GC-I and GC-II at 1200 degrees C. GC-I and GC-II, whose solid parts contain 74 and 78 vol.% alpha-cordierite and whose compressive strengths are 35 and 50 MPa, respectively, have the respective linear thermal expansion coefficients of 1.51x10(-6) and 1.43x10(-6)/ degrees C. The fly ash alpha-cordierite glass-ceramics can be employed as kiln furniture, honeycomb substrates for catalysts, and heat exchangers. PMID:15811690

He, Yong; Cheng, Weimin; Cai, Hesheng

2005-04-11

248

The Validation of a Food Label Literacy Questionnaire for Elementary School Children  

ERIC Educational Resources Information Center

Objective: To determine the reliability and validity of a 10-item questionnaire, the Food Label Literacy for Applied Nutrition Knowledge questionnaire. Methods: Participants were elementary school children exposed to a 90-minute school-based nutrition program. Reliability was assessed via Cronbach alpha and intraclass correlation coefficient…

Reynolds, Jesse S.; Treu, Judith A.; Njike, Valentine; Walker, Jennifer; Smith, Erica; Katz, Catherine S.; Katz, David L.

2012-01-01

249

Age Band 1 of the Movement Assessment Battery for Children-Second Edition: Exploring Its Usefulness in Mainland China  

ERIC Educational Resources Information Center

The aim of this paper was to examine the validity and reliability of age band 1 of the Movement Assessment Battery for Children-Second Edition (MABC-2) in preparation for its standardization in mainland China. Interrater and test-retest reliability of the MABC-2 was estimated using Intraclass Correlation Coefficient (ICC). Cronbach's alpha for…

Hua, Jing; Gu, Guixiong; Meng, Wei; Wu, Zhuochun

2013-01-01

250

Farmers' Attitudes and Skills of Farm Business Management in Jordan  

ERIC Educational Resources Information Center

This study aimed to investigate farmers' attitudes and skills of farm management. Two scales were constructed as an instrument for data collection, based on a sample of 100 farm units. Cronbach's alpha coefficients were 0.84 or higher, which indicated that the instrument scales were internally consistent. Non-parametric tests were used to analyze…

Al-Rimawi, Ahmad Sh.; Karablieh, Emad K.; Al-Qadi, Abdulfatah S.; Al-Qudah, Hussein F.

2006-01-01

251

The Effect of Music on the Test Scores of the Students in Limits and Derivatives Subject in the Mathematics Exams Done with Music  

ERIC Educational Resources Information Center

In the exams based on limits and derivatives, in this study, it was tried to determine that if there was any difference in students' test scores according to the type of music listened to and environment without music. For this purpose, the achievement test including limits and derivatives and whose reliability coefficient of Cronbach Alpha is…

Kesan, Cenk; Ozkalkan, Zuhal; Iric, Hamdullah; Kaya, Deniz

2012-01-01

252

Confirmatory Factor Analysis of Persian Adaptation of Multidimensional Students' Life Satisfaction Scale (MSLSS)  

ERIC Educational Resources Information Center

Validity and reliability of Persian adaptation of MSLSS in the 12-18 years, middle and high school students (430 students in grades 6-12 in Bushehr port, Iran) using confirmatory factor analysis by means of LISREL statistical package were checked. Internal consistency reliability estimates (Cronbach's coefficient [alpha]) were all above the…

Hatami, Gissou; Motamed, Niloofar; Ashrafzadeh, Mahshid

2010-01-01

253

A series of lower bounds to the reliability of a test  

Microsoft Academic Search

Two well-known lower bounds to the reliability in classical test theory, Guttman's 2 and Cronbach's coefficient alpha, are shown to be terms of an infinite series of lower bounds. All terms of this series are equal to the reliability if and only if the test is composed of items which are essentially tau-equivalent. Some practical examples, comparing the first 7

J. M. F. ten Berge; Frits E. Zegers

1978-01-01

254

Alpha-factor structural gene mutations in Saccharomyces cerevisiae: effects on alpha-factor production and mating.  

PubMed Central

The role of alpha-factor structural genes MF alpha 1 and MF alpha 2 in alpha-factor production and mating has been investigated by the construction of mf alpha 1 and mf alpha 2 mutations that totally eliminate gene function. An mf alpha 1 mutant in which the entire coding region is deleted shows a considerable decrease in alpha-factor production and a 75% decrease in mating. Mutations in mf alpha 2 have little or no effect on alpha-factor production or mating. The mf alpha 1 mf alpha 2 double mutants are completely defective in mating and alpha-factor production. These results indicate that at least one alpha-factor structural gene product is required for mating in MAT alpha cells, that MF alpha 1 is responsible for the majority of alpha-factor production, and that MF alpha 1 and MF alpha 2 are the only active alpha-factor genes. Images

Kurjan, J

1985-01-01

255

Workshop on Precision Measurements of $\\alpha_s$  

SciTech Connect

These are the proceedings of the Workshop on Precision Measurements of {alpha}{sub s} held at the Max-Planck-Institute for Physics, Munich, February 9-11, 2011. The workshop explored in depth the determination of {alpha}{sub s}(m{sub Z}) in the {ovr MS} scheme from the key categories where high precision measurements are currently being made, including DIS and global PDF fits, {tau}-decays, electro-weak precision observables and Z-decays, event-shapes, and lattice QCD. These proceedings contain a short summary contribution from the speakers, as well as the lists of authors, conveners, participants, and talks.

Bethke, Siegfried; /Munich, Max Planck Inst.; Hoang, Andre H.; /Vienna U.; Kluth, Stefan; /Munich, Max Planck Inst.; Schieck, Jochen; /Munich U.; Stewart, Iain W.; Aoki, S.; Beneke, M.; Bethke, S.; Blumlein, J.; Brambilla, N.; Brodsky, S.; /MIT, LNS

2011-10-01

256

Effects of land cover on runoff coefficient  

NASA Astrophysics Data System (ADS)

SummaryLand cover is considered to have significant influence on the hydrologic response of a river basin. In this study, we assessed how changes in land cover over time affected flood behaviour from 1988 to 2005, in the Upper Ping River Basin, northern Thailand. We correlated the types of land cover with rainfall-runoff behaviour for smaller and larger flood events taking place during this period. To quantify land cover, nine Landsat 5 TM images taken during the dry season (January or February) were obtained and processed to examine inter-annual land cover changes. From the networks of daily read rainfall data and stream gaugings available across the basin, 68 rainfall and 11 runoff stations were selected to evaluate peak flow rate and runoff coefficient for flood events. For individual sub-catchments, strong non-linear correlations were found between the overall runoff coefficient and peak flow rates for flood events. These runoff coefficients to peak flow relationships varied from year to year with different land cover for each sub-catchment. From these relationships within a particular sub-catchment, we determined relationships between different types of land cover and runoff coefficient for the 2, 5, 10 and 15 year Annual Recurrence Interval (ARI) peak flood events. We found that runoff coefficient increased with increasing forest proportion for these specified peak flood conditions, on nine out of eleven sub-catchments. On the other hand, the runoff coefficient associated with these peak flood events decreased as agricultural and disturbed forest areas increased. The influence of land cover on runoff coefficient was, however, found to be very different between smaller (lower than ˜2 year ARI) and larger flood events (larger than ˜2 year ARI). Runoff coefficient is higher for high forest cover during larger flood events; but for smaller flood events, runoff coefficient is lower when forest cover is high. This is due to the fact that for smaller flood events, rainfall loss rate for the forest area is normally higher than that of the non-forest area according to higher evapotranspiration and soil moisture capacity. Forests have proved to potentially offer flood mitigation benefits for smaller flood events. However, for larger flood events the situation of the basin can be different, especially on a basin with higher antecedent soil moisture or even under saturation stage. Antecedent soil moisture from the previous storms could be better retained within the forest area than the non-forest area due to deeper rote zone and higher soil moisture holding capacity of the forest area compared to non-forest area. For the larger flood events, forest area tends to produce more runoff than non-forest area as found in this study. These findings gave us a more thorough understanding of the effect of land cover types on flood behaviour at different stages of soil moisture conditions, and the severity of storm events. It can be useful for land use and flood management of the river basin.

Sriwongsitanon, Nutchanart; Taesombat, Wisuwat

2011-11-01

257

A parameterization scheme for the x-ray linear attenuation coefficient and energy absorption coefficient.  

PubMed

A novel parameterization of x-ray interaction cross-sections is developed, and employed to describe the x-ray linear attenuation coefficient and mass energy absorption coefficient for both elements and mixtures. The new parameterization scheme addresses the Z-dependence of elemental cross-sections (per electron) using a simple function of atomic number, Z. This obviates the need for a complicated mathematical formalism. Energy dependent coefficients describe the Z-direction curvature of the cross-sections. The composition dependent quantities are the electron density and statistical moments describing the elemental distribution. We show that it is possible to describe elemental cross-sections for the entire periodic table and at energies above the K-edge (from 6 keV to 125 MeV), with an accuracy of better than 2% using a parameterization containing not more than five coefficients. For the biologically important elements 1 < or = Z < or = 20, and the energy range 30-150 keV, the parameterization utilizes four coefficients. At higher energies, the parameterization uses fewer coefficients with only two coefficients needed at megavoltage energies. PMID:15083673

Midgley, S M

2004-01-21

258

Electron-Ion Recombination Rate Coefficient Measurements in a Flowing Afterglow Plasma  

NASA Technical Reports Server (NTRS)

The flowing-afterglow technique in conjunction with computer modeling of the flowing plasma has been used to determine accurate dissociative-recombination rate coefficients alpha for the ions O2(+), HCO(+), CH5(+), C2H5(+), H3O(+), CO2(+), HCO2(+), HN2O(+), and N2O(+) at 295 K. We find that the simple form of data analysis that was employed in earlier experiments was adequate and we largely confirm earlier results. In the case of HCO(+) ions, published coefficients range from 1.1 X 10(exp -7) to 2.8 x 10(exp -7) cu cm/S, while our measurements give a value of 1.9 x 10(exp -7) cu cm/S.

Gougousi, Theodosia; Golde, Michael F.; Johnsen, Rainer

1996-01-01

259

Thermodiffusion Coefficient for Binary Liquid Hydrocarbon Mixtures  

NASA Astrophysics Data System (ADS)

In this work, the thermogravitational technique has been used to determine the thermodiffusion coefficient of 18 binary mixtures of normal alkanes formed with the n-octadecane as the densest component and mixed with normal alkanes from n-pentane to n-tridecane in two series of experimental tests (nine binary mixtures with mass fraction c = 0.5 and nine binary mixtures with molar fraction x = 0.5 in each component for each mixture). The measurement of the steady separation of these mixtures in the thermogravitational column, as well as their corresponding thermophysical properties, has been determined at the average temperature of 25°C. The main result shows a linear dependency of the thermodiffusion coefficient on the relative density difference, and this in both series of experimental tests (mass and molar fraction equal to 0.5).

Blanco, P.; Bou-Ali, M. M.; Platten, J. K.; Madariaga, J. A.; Urteaga, P.; Santamaría, C.

2007-09-01

260

Rotational dissipation and the Miesowicz coefficients  

NASA Astrophysics Data System (ADS)

In this work, we will study the relative contribution of each of the two dissipative channels of the Eriksen, Leslie, and Parodi (ELP) approach to the observed values of the Miesowicz viscosity coefficients of the nematic liquid crystals. According to the fundamental equation of the liquid crystal’s viscosity dissipative process, T?=-?d3r{?ijAij+h??N?} , there are two channels by which the nematic viscous dissipation can occur: or it occurs by means of a shear flow configuration, where Aij is the characterizing term, or it occurs by means of a rotational configuration, where N? is the characterizing term (these parameters will be defined in the paper). It will be also shown that this relative contribution can be measured by a simple relationship connecting the Miesowicz coefficients, which exhibits a quasitemperature independent behavior, suggesting that it is nearly constant through the entire domain of the nematic phase.

Simões, M.; Yamaguti, K.; Palangana, A. J.

2009-12-01

261

Materials with Tailored Thermal Expansion Coefficient  

NASA Astrophysics Data System (ADS)

Designing materials with tailored coefficient of thermal expansion (CTE) has applications in a number of fields, including biomedical and mechanical engineering and solar energy. It is particularly important to combine a desired (usually low) CTE with mechanical robustness. Most of previous work has been focused on designing low-CTE materials by modifying compounds at the chemical level. It is also possible to design materials with tailored CTE by using specific topologies of different materials to achieve overall properties outside the range of the constituent materials. Here, we exploit buckling in laminated periodic structures to design materials whose coefficient of thermal expansion can be tuned (from positive to negative) by varying the unit cell geometry.

Bertoldi, Katia; Liu, Jia; Shan, Sicong; Kang, Sung Hoon

2013-03-01

262

Solute concentration effect on osmotic reflection coefficient.  

PubMed Central

A theory for the effect of concentration on osmotic reflection coefficient, correct to first order, was developed at the molecular level by considering the effect of solute-solute interactions on solute concentration and the fluid stress tensor within a solvent-filled pore. The solvent was modeled as a continuous fluid and potential energies between solute molecules and the pore wall were assumed to be pairwise additive. Although the theory is more general, calculations are presented only for excluded volume effects (hard-sphere for solute, hard-wall for pore). The relationship between the first-order concentration effect and the infinite dilution value of reflection coefficient appears to be geometry independent. The theory is discussed in light of experimental studies of osmotic flow that have recently appeared in the literature.

Adamski, R P; Anderson, J L

1983-01-01

263

Gate Control Coefficient Effect on CNFET Characteristic  

SciTech Connect

The development of carbon nanotube field-effect transistor (CNFET) as alternative to existing transistor technology has long been published and discussed. The emergence of this device offers new material and structure in building a transistor. This paper intends to do an analysis of gate control coefficient effect on CNFET performance. The analysis is based on simulation study of current-voltage (I-V) characteristic of ballistic CNFET. The simulation study used the MOSFET-like CNFET mathematical model to establish the device output characteristic. Based on the analysis of simulation result, it is found that the gate control coefficient contributes to a significant effect on the performance of CNFET. The result also shown the parameter could help to improve the device performance in terms of its output and response as well. Nevertheless, the characteristic of the carbon nanotube that acts as the channel is totally important in determining the performance of the transistor as a whole.

Sanudin, Rahmat; Ma'Radzi, Ahmad Alabqari; Nayan, Nafarizal [Faculty of Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia, Johor (Malaysia)

2009-06-01

264

Nonlinear Diffusions and Stable-Like Processes with Coefficients Depending on the Median or VaR  

SciTech Connect

The paper is devoted to the well-posedness for nonlinear McKean-Vlasov type diffusions with coefficients depending on the median or, more generally, on the {alpha}-quantile of the underlying distribution. The median is not a continuous function on the space of probability measures equipped with the weak convergence. This is one reason why well-posedness of the SDE considered in the paper does not follow by standard arguments.

Kolokoltsov, Vassili N., E-mail: v.kolokoltsov@warwick.ac.uk [University of Warwick, Department of Statistics (United Kingdom)

2013-08-01

265

Studying Reionization using Lyman Alpha Galaxies  

NASA Astrophysics Data System (ADS)

Resonant scattering of Lyman alpha photons by neutral hydrogen hides Lyman alpha emission lines from view prior to the epoch of reionization. This simple principle provides us with several ways to study the history of reionization. These include the Lyman alpha luminosity function, observed spatial distributions of Lyman alpha emitters, Lyman alpha equivalent width distributions, and the minimum ionized volume test. I will present a brief overview of the underlying physics, the context from other reionization methods, and the observational constraints so far from the various Lyman-alpha based tests. I will then discuss our group's ongoing Lyman alpha searches at z 8. Finally, I will discuss recent results on characterizing the distribution of velocity offsets between the Lyman alpha line and the systemic velocity-- a quantity that plays an important role in interpreting the results of Lyman-alpha based reionization tests.

Rhoads, James E.

2012-05-01

266

Spearman's Rank-Difference Coefficient of Correlation  

NSDL National Science Digital Library

This tutorial, created by Thomas W. MacFarland of Nova Southeastern University, explains the theory and use of the Spearman's Rank-Difference Correlation Coefficient and demonstrates it with an example on exam scores, homework scores, and project scores. Data sets are provided in both SPSS and Minitab code. This is a great resource for anyone interested in a more in-depth study of statistics.

Macfarland, Thomas W.

2009-01-21

267

Quenching of spontaneous emission coefficients in plasmas  

SciTech Connect

We have observed changing Einstein coefficients of spontaneous emission as a function of electron density in CO/sub 2/ laser-produced plasmas. These measurements are based on the intensity branching ratio of CIV lines 5801 to 5812 A and 312.41 to 312.46 A which share a common upper level. Similar observations for CIII lines are also discussed. 12 refs., 3 figs.

Chung, Y.; Lemaire, P.; Suckewer, S.

1987-09-01

268

An alternative diffraction coefficient for the wedge  

NASA Astrophysics Data System (ADS)

A geometrical theory of diffraction (GTD) interpretation of a uniform solution for the wedge given by Mohsen is given. The diffraction coefficients are equal to those given by Kouyoumjian and Pathak except that the Fresnel argument in the two solutions are different. This uniform geometrical theory of diffraction (UTD) result is compared with exact series expansions for a plane wave incident on a 90 deg wedge.

Jakobsen, K. R.

1984-02-01

269

Pearson's Product-Moment Coefficient of Correlation  

NSDL National Science Digital Library

This tutorial, created by Thomas W. MacFarland of Nova Southeastern University, explains the theory and use of Pearson's Product Moment Coefficient of Correlation and demonstrates it with an example on GPA and test scores. Data sets are provided in both SPSS and Minitab code. This is a great resource for anyone looking for a more in-depth study of statistics. This could be used as either a teaching guide for educators or simply further practice for students.

Macfarland, Thomas W.

2009-09-11

270

Seebeck coefficient measurements of lithium isotopes  

NASA Astrophysics Data System (ADS)

Lithium, owing to its many advantages, is of immense interest to the fusion community for its use as plasma facing component (PFC) material. Various experiments are under progress in the Center for Plasma Material Interactions (CPMI) at the University of Illinois at Urbana Champaign (UIUC) aimed at understanding the plasma-lithium interactions. In one such experiment called Solid/Liquid Lithium Divertor Experiment (SLiDE), it was recently observed that the flow of liquid lithium in the presence of magnetic fields is dominated by thermoelectric Magnetohydrodynamic (TEMHD) effects. To describe these results accurately, a knowledge of the thermoelectric properties of lithium is essential. For this purpose, an apparatus to measure the Seebeck coefficient of lithium was developed. Using this apparatus, the Seebeck coefficient of lithium as a function of temperature has been obtained. The Seebeck coefficient of lithium-7 is found to gradually increase from 11 ?V/K to 25 ?V/K, as the temperature is raised from 25 °C to 240 °C. These measurements are in good agreement with Kendall's thermoelectric measurements on natural Li. Furthermore, using the same apparatus, the thermoelectric curve of lithium-6 is obtained and for the first time are reported in this paper.

Surla, V.; Tung, M.; Xu, W.; Andruczyk, D.; Neumann, M.; Ruzic, D. N.; Mansfield, D.

2011-08-01

271

Virial Coefficients Using Different Equations of State  

NASA Astrophysics Data System (ADS)

Inexpensive desktop computers and powerful computer algebra software packages have made it possible for students and faculty to look at problems unthinkable a few years past because of the intensive algebra involved. One such problem is the derivation of expressions for the first three virial coefficients when using different equations of state. Using Mathematica, expressions for the virial coefficients at constant volume, constant pressure, and the fugacity have been derived for several equations of state. The results of these calculations are shown in two plots with experimental data. These plots serve as a check on the validity of the expressions derived using Mathematica. Our purpose is to illustrate the actual Mathematica instructions that lead to the virial coefficients for the well-known van der Waals equation of state. The set of Mathematica instructions for this equation of state will serve as a model for other more sophisticated equations of state. In our study we selected the Redlich-Kwong and the Gibbons, Laughton modification to the Redlich-Kwon equations of state.

Wakefield, Charles B.; Phillips, Constance

2000-10-01

272

The electron diffusion coefficient in Jupiter's magnetosphere  

NASA Technical Reports Server (NTRS)

A steady-state model of Jupiter's electron radiation belt is developed. The model includes injection from the solar wind, radial diffusion, energy degradation by synchrotron radiation, and absorption at Jupiter's surface. A diffusion coefficient of the form D sub RR/R sub J squared = k times R to the m-th power is assumed, and then observed data on synchrotron radiation are used to fit the model. The free parameters determined from this fit are m = 1.95 plus or minus 0.5, k = 1.7 plus or minus 0.5 x 10 to the 9th power per sec, and the magnetic moment of injected particles equals 770 plus or minus 300 MeV/G. The value of m shows quite clearly that the diffusion is not caused by magnetic pumping by a variable solar wind or by a fluctuating convection electric field. The process might be field line exchange driven by atmospheric-ionospheric winds; our diffusion coefficient has roughly the same radial dependence but is considerably smaller in magnitude than the upper bound diffusion coefficients recently suggested for this process by Brice and McDonough (1973) and Jacques and Davis (1972).

Birmingham, T.; Northrop, T.; Baxter, R.; Hess, W.; Lojko, M.

1974-01-01

273

Disease characterization of active appearance model coefficients  

NASA Astrophysics Data System (ADS)

We previously reported on 2D and 3D Active Appearance Models (AAM) for automated segmentation of cardiac MR. AAMs are shown useful for such segmentations because they exploit prior knowledge about cardiac shape and image appearance, yet segmentation of object borders might not be the only benefit of AAMs. An AAM represents objects as a linear combination of shape and texture variations applied to a mean object via Principal Component Analysis (PCA) to form an integrated model. This model captures enough shape, texture, and motion variations to accurately synthesize reconstructions of target objects from a finite set of parameters. Because of this, we hypothesize that AAM coefficients may be used for the classification of disease abnormalities. PCA is useful for reducing the dimensionality of vectors, however it does not produce vectors optimal for the separation of classes needed for disease classification. Discriminate analysis such as Linear Discriminate Analysis (LDA) and Kernel Discriminate Analysis (KDA) are dimension reducing techniques with the added benefit of supervised learning for the purpose of classification. Once AAM segmentation is complete, disease probabilities are computed from model coefficients via discriminate analysis. Preliminary results on model coefficients show tendency of disease separation for certain disease classes.

Mitchell, Steven C.; Lelieveldt, Boudewijn P. F.; Bosch, H. G.; Reiber, Johan H. C.; Sonka, Milan

2003-05-01

274

Edge Diffraction Coefficients around Critical Rays  

NASA Astrophysics Data System (ADS)

The classical GTD (Geometrical Theory of Diffraction) gives a recipe, based on high-frequency asymptotics, for calculating edge diffraction coefficients in the geometrical regions where only diffracted waves propagate. The Uniform GTD extends this recipe to transition zones between irradiated and silent regions, known as penumbra. For many industrial materials, e.g. steels, and frequencies utlized in industrial ultrasonic transducers, that is, around 5 MHz, asymptotics suggested for description of geometrical regions supporting the head waves or transition regions surrounding their boundaries, known as critical rays, prove unsatisfactory. We present a numerical extension of GTD, which is based on a regularized, variable step Simpson's method for evaluating the edge diffraction coefficients in the regions of interference between head waves, diffracted waves and/or reflected waves. In mathematical terms, these are the regions of coalescence of three critical points - a branch point, stationary point and/or pole, respectively. We show that away from the shadow boundaries, near the critical rays the GTD still produces correct values of the edge diffraction coefficients.

Fradkin, L.; Harmer, M.; Darmon, M.

2014-04-01

275

The photon attenuation coefficients of barite, marble and limra  

Microsoft Academic Search

The linear attenuation coefficients ? (cm?1) and total mass attenuation coefficients ?? (cm2 g?1) of ?-rays for barite, marble and limra have been calculated using the XCOM program (Version 3.1) at energies from 1 keV to 300 MeV. The calculated results were compared with the estimation coefficients ?? based on the measured total linear attenuation coefficients (?).

I. Akkurt; S. Kilincarslan; C. Basyigit

2004-01-01

276

Distributions of the Two-Dimensional DCT Coefficients for Images  

Microsoft Academic Search

For a two-dimensional discrete cosine transform (DCT) image coding system, there have been different assumptions concerning the distributions of the transform coefficients. This paper presents results of distribution tests that indicate that for many images the statistics of the coefficients are best approximated by a Gaussian distribution for the DC coefficient and a Laplacian distribution for the other coefficients. Furthermore,

R. Reininger; J. Gibson

1983-01-01

277

Alpha-particle autoradiography in CR-39: The determination of the microdistribution of activity and trace element analysis  

NASA Astrophysics Data System (ADS)

New and elaborate techniques for alpha-particle autoradiography of thick specimens based on the plastic nuclear track detector CR-39 have been developed. These permit a full analysis of both trace element and microdistribution of alpha-active nuclides present. The important features of the techniques are: (1) reliable low level counting down to 10 -15Ci g -1, (2) high resolution alpha-particle spectroscopy in CR-39, (3) determination of the absolute abundance of alpha active nuclides present in the specimen, (4) determination of the distribution of emission with height up to 30 microns above the surface of the autoradiograph, (5) the local determination of the radon diffusion coefficient in the specimen which is needed to calculate the activity levels of 222Rn and daughter nuclei, (6) the analysis of small and large clusters of alpha-particle activity recorded on the autoradiograph. These techniques are briefly discussed.

Peter Fews, A.; Henshaw, Denis L.

278

Spectral absorption coefficient of molten aluminum oxide from 0.385 to 0.780 {mu}m  

SciTech Connect

The spectral extinction coefficient, k{sub {lambda}}, and the absorption coefficient, {alpha}{sub {lambda}}, of liquid aluminum oxide were determined from emission measurements on partially molten single-crystal sapphire filaments. Measurements were made at wavelengths from 0.385 to 0.780 {mu}m in both argon and oxygen atmospheres and at 0.650 {mu}m in a 10% H{sub 2}-90% N{sub 2} mixture. The values of {alpha}{sub {lambda}} were found to vary with the time for which the specimen had been molten and achieved different steady-state values in the three processing atmospheres. A decrease in {alpha}{sub {lambda}} with wavelength (Urbach tail) was observed from 0.385 {mu}m to about 0.420 {mu}m in argon and 0.490 {mu}m in oxygen, and approximately constant values were obtained at longer wavelengths. Steady-state values of {alpha}{sub {lambda}} at the optical pyrometer wavelength of 6.650 {mu}m were 9 {+-} 2 cm{sup {minus}1} in argon, 41 {+-} 8 cm{sup {minus}1} in oxygen, and 14 {+-} 2 cm{sup {minus}1} in the 10% hydrogen-90% nitrogen gas mixture.

Weber, J.K.R.; Krishnan, S.; Anderson, C.D.; Nordine, P.C. [Intersonics, Inc., Northbrook, IL (United States)

1995-03-01

279

Meet the Alpha-Pets.  

ERIC Educational Resources Information Center

"Alpha-Pets" are the focal point of an integrated, multidisciplinary curriculum. Each pet is featured for a week in a vocabulary-rich story and introduces related activities beginning with the featured letter, such as the four food groups during Freddie Fish's week or universe during Ulysses Unicorn's week. (MT)

Zitlaw, Jo Ann Bruce; Frank, Cheryl Standish

1985-01-01

280

Alpha proton x ray spectrometer  

NASA Technical Reports Server (NTRS)

Mars Pathfinder will carry an alpha-proton x ray spectrometer (APX) for the determination of the elemental chemical composition of Martian rocks and soils. The instrument will measure the concentration of all major and some minor elements, including C, N, and O at levels above typically 1 percent.

Rieder, Rudi; Waeke, H.; Economou, T.

1994-01-01

281

Safety of Alpha Olefin Sulfonates  

Microsoft Academic Search

Alpha olefin sulfonates (AOS) belong to the anionic surfac-tant class. They are efficient, readily biodegradable cleaning\\u000a agents. This paper reviews the safety aspects of AOS, in-cluding acute toxicity, teratogenicity, animal sensitization, human\\u000a sensitization, chronic toxicity and lifetime studies -cancer bioassay.

Gary Ter Haar

1983-01-01

282

Alcoholism, Alpha Production, and Biofeedback  

ERIC Educational Resources Information Center

Electroencephalograms of 20 alcoholics and 20 nonalcoholics were obtained. Data indicated that alcoholics produced less alpha than nonalcoholics. In one training condition subjects were given accurate biofeedback, whereas in the other condition subjects were given random (noncontingent) feedback. Accurate biofeedback did not result in greater…

Jones, Frances W.; Holmes, David S.

1976-01-01

283

The Spitzer Lyman Alpha Survey  

NASA Astrophysics Data System (ADS)

Determining the star formation history of high-redshift galaxies is vital for understanding galaxy formation and reionization. These galaxies are typically selected using their rest-frame ultraviolet (UV) fluxes, thus their old stellar populations can be missed. Spitzer Imaging at 3.6 microns is essential to measure the rest-frame optical fluxes of high redshift galaxies and therefore estimate the total stellar mass. Lyman-alpha galaxies form fully half of the known galaxies at zD3-6. The strength of the Lyman-alpha line, at first glance, indicates a young (~10 million years old) and dust-free population. This picture of Lyman-alpha galaxies as a class of less massive and young objects is simultaneously being confirmed and challenged thanks to Spitzer data. While most of the Lyman-alpha galaxies are young and low-mass, a subset of them are more massive and/or dusty. That there may be two types of Lyman-alpha emitters, is based on the only those few studies that analyze individual galaxies, and not co-addition of a sample of non-detections. In order to robustly investigate the statistical fraction of older and younger Lyman-alpha galaxies at any given redshift and to find out the redshift evolution of this fraction, we simultaneously need a large sample at many redshifts, and we need deep imaging so we can study individual objects. We propose a systematic IRAC 3.6 imaging survey of a spectroscopically confirmed sample of about 100 Lyman-alpha galaxies between redshifts 3.1 8; (2) The dust extinction in the UV, and therefore a correction to their present star-formation rates; (3) The fraction of galaxies with old stellar populations as a function of redshift.

Rhoads, James; Finkelstein, Steven; Grogin, Norman; Malhotra, Sangeeta; Pirzkal, Norbert; Wang, Junxian

2009-04-01

284

Étude de la réaction (alpha, 2alpha) sur 12C par particules alpha de 100 MeV  

Microsoft Academic Search

The reaction 12C(alpha, 2alpha)8Be is observed by using 90 MeV alpha particles in ionographic matter. The excitation energy spectrum of the residual nucleus 8Be clearly shows the 0+, 2+, 4+ states. The spectrum calculated with the cluster-model wave function for 12C is compared with the observed data. The energy spectrum of the energetic outgoing alpha-particle is calculated and compared with

C. Jacquot; Y. Sakamoto; M. Jung; C. Baixeras-Aiguabella; L. Girardin; H. Braun

1970-01-01

285

A synopsis of collective alpha effects and implications for ITER  

SciTech Connect

This paper discusses the following: Alpha Interaction with Toroidal Alfven Eigenmodes; Alpha Interaction with Ballooning Modes; Alpha Interaction with Fishbone Oscillations; and Implications for ITER.

Sigmar, D.J.

1990-10-01

286

Transport coefficients of hard sphere fluids  

NASA Astrophysics Data System (ADS)

New calculations have been made of the self-diffusion coefficient D, the shear viscosity ?s , the bulk viscosity ?b and thermal conductivity ? of the hard sphere fluid, using molecular dynamics (MD) computer simulation. A newly developed hard sphere MD scheme was used to model the hard sphere fluid over a wide range up to the glass transition (~0.57 packing fraction). System sizes of up to 32 000 hard spheres were considered. This set of transport coefficient data was combined with others taken from the literature to test a number of previously proposed analytical formulae for these quantities together with some new ones given here. Only the self-diffusion coefficient showed any substantial n dependence for N > 500 at equilibrium fluid densities ( ? < 0.494). D increased with N , especially at intermediate densities in the range ? ~ 0.3-0.35. The expression for the packing fraction dependence of D proposed by Speedy, R. J., 1987, Molec. Phys. , 62 , 509 was shown to fit these data well for N ~ 500 particle systems. We found that the packing fraction ? dependence of the two viscosities and thermal conductivity, generically denoted by X , were represented well by the simple formula X/X0 = 1/[1 -( ? / gr;1)]m within the equilibrium fluid range 0 < ? <0.493. This formula has two disposable parameters, ?1 and m, and X0 is the value of the property X in the limit of zero density. This expression has the same form as the Krieger-Dougherty formula (Kreiger, I. M., 1972,Adv. Colloid. Interface Sci. , 3, 111) which is used widely in the colloid literature to represent the packing fraction dependence of the Newtonian shear viscosity of monodisperse colloidal near-hard spheres. Of course, in the present case, X0 was the dilute gas transport coefficient of the pure liquid rather than the solvent viscosity. It was not possible to fit the transport coefficient normalized by their Enskog values with such a simple expression because these ratios are typically of order unity until quite high packing fractions and then diverge rapidly at higher values over a relatively narrow density range. At the maximum equilibrium fluid packing fraction ? = 0.494 for both the hard sphere fluid and the corresponding colloidal case a very similar value was found for ?s/?0~ 30-40, suggesting that the 'crowding' effects and their consequences for the dynamics in this region of the phase diagram in the two types of liquid have much in common. For the hard sphere by MD, D0/D ~ 11 at the same packing fraction, possibly indicating the contribution from 'hydrodynamic enhancement' of this transport coefficient, which is largely absent for the shear viscosity. Interestingly the comparable ratio for hard sphere colloids is the same.

Sigurgeirsson, H.; Heyes, D. M.

287

Computing confidence intervals for standardized regression coefficients.  

PubMed

With fixed predictors, the standard method (Cohen, Cohen, West, & Aiken, 2003, p. 86; Harris, 2001, p. 80; Hays, 1994, p. 709) for computing confidence intervals (CIs) for standardized regression coefficients fails to account for the sampling variability of the criterion standard deviation. With random predictors, this method also fails to account for the sampling variability of the predictor standard deviations. Nevertheless, under some conditions the standard method will produce CIs with accurate coverage rates. To delineate these conditions, we used a Monte Carlo simulation to compute empirical CI coverage rates in samples drawn from 36 populations with a wide range of data characteristics. We also computed the empirical CI coverage rates for 4 alternative methods that have been discussed in the literature: noncentrality interval estimation, the delta method, the percentile bootstrap, and the bias-corrected and accelerated bootstrap. Our results showed that for many data-parameter configurations--for example, sample size, predictor correlations, coefficient of determination (R²), orientation of ? with respect to the eigenvectors of the predictor correlation matrix, RX--the standard method produced coverage rates that were close to their expected values. However, when population R² was large and when ? approached the last eigenvector of RX, then the standard method coverage rates were frequently below the nominal rate (sometimes by a considerable amount). In these conditions, the delta method and the 2 bootstrap procedures were consistently accurate. Results using noncentrality interval estimation were inconsistent. In light of these findings, we recommend that researchers use the delta method to evaluate the sampling variability of standardized regression coefficients. PMID:24079926

Jones, Jeff A; Waller, Niels G

2013-12-01

288

Q (Alpha) Function and Squeezing Effect  

NASA Technical Reports Server (NTRS)

The relation of squeezing and Q(alpha) function is discussed in this paper. By means of Q function, the squeezing of field with gaussian Q(alpha) function or negative P(a)function is also discussed in detail.

Yunjie, Xia; Xianghe, Kong; Kezhu, Yan; Wanping, Chen

1996-01-01

289

Osmotic coefficients of trialkyl phosphates in water  

SciTech Connect

Osmotic and activity coefficients are reported at several temperatures for triethyl phosphate (TEP) and tripropyl phosphate (TPP) at low concentrations in water. TEP forms solutions that do not depart from ideality as much as do those formed from TPP. At 15 /sup 0/C the total excess Gibbs energies were -11 and -32 J.kg/sup -1/ at 0.05 mol.kg/sup -1/ for TEP and TPP, respectively. For TEP, the nonidealities resulted from a balance between entropic and enthalpic effects. 7 references, 2 figures, 1 table.

Sagert, N.H.

1984-01-01

290

Studies of Gaseous Multiplication Coefficient in Isobutane  

SciTech Connect

This work presents the studies of gaseous multiplication coefficient behavior for isobutane, as function of the reduced electric field, by means of signal amplitude analysis. The experimental method used is based on the Pulsed Townsend technique, which follows from Townsend equation solution for a uniform electric field. In our configuration, the anode is made of a high resistivity (2.10{sup 12} OMEGA.cm) glass, while the cathode is of aluminium. In order to validate the technique and to analyze effects of non-uniformity, results for nitrogen, which has well-established data available in literature, are also presented.

Lima, Iara B.; Vivaldini, Tulio C. [Instituto de Pesquisas Energeticas e Nucleares, 05508-000, Cidade Universitaria, Sao Paulo (Brazil); Goncalves, Josemary A. C.; Botelho, Suzana; Bueno Tobias, Carmen C. [Instituto de Pesquisas Energeticas e Nucleares, 05508-000, Cidade Universitaria, Sao Paulo (Brazil); Departamento de Fisica, Pontificia Universidade Catolica de Sao Paulo, 01303-050, Sao Paulo (Brazil); Ridenti, Marco A.; Pascholati, Paulo R. [Instituto de Fisica, Universidade de Sao Paulo, 05508-090, Cidade Universitaria, Sao Paulo (Brazil); Fonte, Paulo; Mangiarotti, Alessio [Laboratorio de Instrumentacao e Fisica Experimental de Particulas, Departamento de Fisica da Universidade de Coimbra, 3004-516, Coimbra (Portugal)

2010-05-21

291

Second order hydrodynamic coefficients from kinetic theory  

SciTech Connect

In a relativistic setting, hydrodynamic calculations which include shear viscosity (which is first order in an expansion in gradients of the flow velocity) are unstable and acausal unless they also include terms to second order in gradients. To date such terms have only been computed in supersymmetric N=4 super-Yang-Mills theory at infinite coupling. Here we compute these second-order hydrodynamic coefficients in weakly coupled QCD, perturbatively to leading order in the QCD coupling, using kinetic theory. We also compute them in QED and scalar {lambda}{phi}{sup 4} theory.

York, Mark Abraao; Moore, Guy D. [McGill University, Department of Physics, 3600 rue University, Montreal QC H3A 2T8 (Canada)

2009-03-01

292

Micro-Fluidic Diffusion Coefficient Measurement  

SciTech Connect

A new method for diffusion coefficient measurement applicable to micro-fluidics is pre- sented. The method Iltilizes an analytical model describing laminar dispersion in rect- anglllar ~llicro_channe]s. The Illethod ~vas verified throllgh measllremen~ of fllloresceill diffusivity in water and aqueolls polymer solutions of differing concentration. The diffll- sivity of flllorescein was measlmed as 0.64 x 10-gm2/s in water, 0.49 x 10-gm2/s in the 4 gm/dl dextran solution and 0.38 x 10-9n12/s in the 8 gnl/dl dextran solution.

Forster, F.K.; Galambos, P.

1998-10-06

293

Flash ADC data processing with correlation coefficients  

NASA Astrophysics Data System (ADS)

The large growth of flash ADC techniques for processing signals, especially in applications of streaming data, raises issues such as data flow through an acquisition system, long-term storage, and greater complexity in data analysis. In addition, experiments that push the limits of sensitivity need to distinguish legitimate signals from noise. The use of correlation coefficients is examined to address these issues. They are found to be quite successful well into the noise region. The methods can also be extended to Field Programmable Gate Array modules for compressing the data flow and greatly enhancing the event rate capabilities.

Blyth, D.; Gibson, M.; Mcfarland, D.; Comfort, J. R.

2014-02-01

294

Micro-Fluidic Diffusion Coefficient Measurement  

Microsoft Academic Search

A new method for diffusion coefficient measurement applicable to micro-fluidics is pre-;\\u000asented. The method Iltilizes an analytical model describing laminar dispersion in rect-;\\u000aanglllar ~llicro_channe]s. The Illethod ~vas verified throllgh measllremen~ of fllloresceill;\\u000adiffusivity in water and aqueolls polymer solutions of differing concentration. The diffll-;\\u000asivity of flllorescein was measlmed as 0.64 x 10-gm2\\/s in water, 0.49 x 10-gm2\\/s

F. K. Forster; P. Galambos

1998-01-01

295

Modeling canopy reflectance and microwave backscattering coefficient  

NASA Technical Reports Server (NTRS)

Various approaches to model canopy reflectance (CR) in the visible/infrared region and backscattering coefficient (BSC) in the microwave region are compared and contrasted. It is noted that BSC can be related to CR in the source direction (the 'hot spot' direction). By assuming a frequency dependent leaf reflectance and transmittance it is shown that the observed dependence of BSC on leaf area index, leaf angle distribution, angle of incidence, soil moisture content, and frequency can be simulated by a CR model. Thus both BSC and CR can, in principle, be calculated using a single model which has essentially the same parameters as many CR models do.

Goel, N. S.

1985-01-01

296

Experimental rotordynamic coefficient results for honeycomb seals  

NASA Technical Reports Server (NTRS)

Test results (leakage and rotordynamic coefficients) are presented for seven honeycomb-stator smooth-rotor seals. Tests were carried out with air at rotor speeds up to 16,000 cpm and supply pressures up to 8.2 bars. Test results for the seven seals are compared, and the most stable configuration is identified based on the whirl frequency ratio. Results from tests of a smooth-rotor/smooth-stator seal, a teeth-on-stator labyrinth seal, and the most stable honeycomb seal are compared.

Elrod, David A.; Childs, Dara W.

1988-01-01

297

Quenching of Einstein-coefficients by photons  

SciTech Connect

Experimental evidence is presented for the change of Einstein's A- coefficients for spontaneous transitions from the upper laser level of argon ion laser discharge due to the presence of the high- intensity laser flux. To demonstrate that this quenching effect cannot be attributed to a reduction in self-absorption of the strong spontaneous emission line, absorption and line profile measurements have been performed. Computer modelling of the reduction of self absorption due to Rabi splitting also indicated that this effect is too small to explain the observed quenching of spontaneous line emissions. 13 refs., 11 figs.

Aumayr, F. (Technische Univ., Vienna (Austria). Inst. fuer Allgemeine Physik); Lee, W.; Skinner, C.H.; Suckewer, S. (Princeton Univ., NJ (USA). Plasma Physics Lab.)

1991-03-01

298

Hydration of p-Alkyloxy-Alpha-Alpha-Alpha-Trifluoracetophenone and Water Activity as a Micellar Surface,  

National Technical Information Service (NTIS)

Equilibrium hydration of p-methoxy alpha trifluoroacetophenone (MTFA) in water and anionic micelles of sodium dodecyl sulfate (SDS) has been followed by F NMR and UV spectrometry, and is strongly disfavored by the micelles. The effects can be separated in...

A. D. Angeli A. Cipiciani R. Germani G. Savelli C. A. Bunton

1988-01-01

299

Use of a laser beam with an oblique angle of incidence to measure the reduced scattering coefficient of a turbid medium  

NASA Astrophysics Data System (ADS)

A simple and quick approach is used to measure the reduced scattering coefficient ( mu s `) of a semi-infinite turbid medium having a much smaller absorption coefficient than mu s`. A laser beam with an oblique angle of incidence to the medium causes the center of the diffuse reflectance that is several transport mean-free paths away from the incident point to shift away from the point of incidence by an amount Delta x. This amount is used to compute mu s` by mu s` = sin( alpha i)/(n Delta x), where n is the refractive index of the turbid medium divided by that of the incident medium and alpha i is the angle of incidence measured from the surface normal. For a turbid medium having an absorption coefficient comparable with mu s `, a revision to the above formula is made. This method is tested theoretically by Monte Carlo simulations and experimentally by a video reflectometer.

Wang, Lihong; Jacques, Steven L.

1995-05-01

300

Electron distribution function and recombination coefficient in ultracold plasma in a magnetic field  

SciTech Connect

The electron distribution function and diffusion coefficient in energy space have been calculated for the first time for a weakly coupled ultracold plasma in a magnetic field in the range of magnetic fields B = 100-50000 G for various temperatures. The dependence of these characteristics on the magnetic field is analyzed and the distribution function is shown to depend on the electron energy shift in a magnetic field. The position of the 'bottleneck' of the distribution function has been found to be shifted toward negative energies with increasing magnetic field. The electron velocity autocorrelators as a function of the magnetic field have been calculated; their behavior suggests that the frequency of collisions between charged particles decreases significantly with increasing magnetic field. The collisional recombination coefficient {alpha}{sub B} has been calculated in the diffusion approximation for a weakly coupled ultracold plasma in a magnetic field. An increase in magnetic field is shown to lead to a decrease in {alpha}{sub B} and this decrease can be several orders of magnitude.

Bobrov, A. A.; Bronin, S. Ya.; Zelener, B. B.; Zelener, B. V. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)] [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Manykin, E. A. ['Kurchatov Institute' Russian Research Center (Russian Federation)] ['Kurchatov Institute' Russian Research Center (Russian Federation); Khikhlukha, D. R., E-mail: DKhikhlukha@ihed.ras.ru [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

2013-07-15

301

SDSS-II: Determination of shape and color parameter coefficients for SALT-II fit model  

SciTech Connect

In this study we look at the SALT-II model of Type IA supernova analysis, which determines the distance moduli based on the known absolute standard candle magnitude of the Type IA supernovae. We take a look at the determination of the shape and color parameter coefficients, {alpha} and {beta} respectively, in the SALT-II model with the intrinsic error that is determined from the data. Using the SNANA software package provided for the analysis of Type IA supernovae, we use a standard Monte Carlo simulation to generate data with known parameters to use as a tool for analyzing the trends in the model based on certain assumptions about the intrinsic error. In order to find the best standard candle model, we try to minimize the residuals on the Hubble diagram by calculating the correct shape and color parameter coefficients. We can estimate the magnitude of the intrinsic errors required to obtain results with {chi}{sup 2}/degree of freedom = 1. We can use the simulation to estimate the amount of color smearing as indicated by the data for our model. We find that the color smearing model works as a general estimate of the color smearing, and that we are able to use the RMS distribution in the variables as one method of estimating the correct intrinsic errors needed by the data to obtain the correct results for {alpha} and {beta}. We then apply the resultant intrinsic error matrix to the real data and show our results.

Dojcsak, L.; Marriner, J.; /Fermilab

2010-08-01

302

An analytical model for calculating internal dose conversion coefficients for non-human biota.  

PubMed

To assess the radiation burden of non-human living organisms, dose coefficients are available in the literature, precalculated by assuming an ellipsoidal shape of each organism. A previously developed analytical method was applied for the determination of absorbed fractions inside ellipsoidal volumes from alpha, beta, and gamma radiations to the calculation of dose conversion coefficients (DCCs) for 15 reference organisms, animals and plants, either terrestrial, amphibian, or aquatic, and six radionuclides ((14)C, (90)Sr, (60)Co, (137)Cs, (238)U, and (241)Am). The results were compared with the reference values reported in Publication 108 of the International Commission on Radiological Protection, in which a different calculation approach for DCCs was employed. The results demonstrate that the present analytical method, originally intended for applications in internal dosimetry of nuclear medicine therapy, gives consistent results for all the beta-, beta-gamma-, and alpha-emitting radionuclides tested in a wide range of organism masses, between 8 mg and 1.3 kg. The applicability of the method proposed can take advantage from its ease of implementation in an ordinary electronic spreadsheet, allowing to calculate, for virtually all possible radionuclide emission spectra, the DCCs for ellipsoidal models of non-human living organisms in the environment. PMID:24668284

Amato, Ernesto; Italiano, Antonio

2014-05-01

303

Transport coefficients for the shear dynamo problem at small Reynolds numbers  

SciTech Connect

We build on the formulation developed in S. Sridhar and N. K. Singh [J. Fluid Mech. 664, 265 (2010)] and present a theory of the shear dynamo problem for small magnetic and fluid Reynolds numbers, but for arbitrary values of the shear parameter. Specializing to the case of a mean magnetic field that is slowly varying in time, explicit expressions for the transport coefficients {alpha}{sub il} and {eta}{sub iml} are derived. We prove that when the velocity field is nonhelical, the transport coefficient {alpha}{sub il} vanishes. We then consider forced, stochastic dynamics for the incompressible velocity field at low Reynolds number. An exact, explicit solution for the velocity field is derived, and the velocity spectrum tensor is calculated in terms of the Galilean-invariant forcing statistics. We consider forcing statistics that are nonhelical, isotropic, and delta correlated in time, and specialize to the case when the mean field is a function only of the spatial coordinate X{sub 3} and time {tau}; this reduction is necessary for comparison with the numerical experiments of A. Brandenburg, K. H. Raedler, M. Rheinhardt, and P. J. Kaepylae [Astrophys. J. 676, 740 (2008)]. Explicit expressions are derived for all four components of the magnetic diffusivity tensor {eta}{sub ij}({tau}). These are used to prove that the shear-current effect cannot be responsible for dynamo action at small Re and Rm, but for all values of the shear parameter.

Singh, Nishant K. [Raman Research Institute, Sadashivanagar, Bangalore 560 080 (India); Joint Astronomy Programme, Indian Institute of Science, Bangalore 560 012 (India); Sridhar, S. [Raman Research Institute, Sadashivanagar, Bangalore 560 080 (India)

2011-05-15

304

AlphaSort: A RISC Machine Sort  

Microsoft Academic Search

A new sort algorithm, called AlphaSort, demonstrates that commodity processors and disks can handle commercial batch workloads. Using Alpha AXP processors, commodi~ memory, and arrays of SCSI disks, AlphaSort runs the industry-standard sort benchmark in seven seconds. This beats the best published record on a 32-cpu 32-disk Hypercube by 8:1. On another benchmark, AlphaSort sorted more than a gigabyte in

Chris Nyberg; Tom Barclay; Zarka Cvetanovic; Jim Gray; David B. Lomet

1994-01-01

305

Interferon-alpha induced Raynaud's syndrome.  

PubMed

The cytokine interferon-alpha (IFN-alpha) is increasingly prescribed for a number of indications, especially viral hepatitis and several malignancies. Two patients are described who developed Raynaud's syndrome during treatment with IFN-alpha as adjuvant therapy for high-risk melanoma. With a review of the available literature the symptomatology, possible pathophysiologic mechanisms and treatment options are discussed. PMID:11142493

Kruit, W H; Eggermont, A M; Stoter, G

2000-11-01

306

Alpha-gamma Angular Correlations in the Reaction exp 24 MG( Alpha , alpha sub 1 gamma ) at Esub( Alpha ) = 104 Mev.  

National Technical Information Service (NTIS)

The in-plane alpha sub 1 - gamma angular correlation of the reaction exp 24 Mg( alpha , alpha sub 1 gamma ) has been studied at a bombarding energy of 104 MeV. Double differential cross sections have been measured for 126 pairs of angles by use of a multi...

W. Eyrich A. Hofmann U. Scheib S. Schneider F. Vogler

1977-01-01

307

Atypical Alpha Asymmetry in Adults with ADHD  

ERIC Educational Resources Information Center

Introduction: A growing body of literature suggests atypical cerebral asymmetry and interhemispheric interaction in ADHD. A common means of assessing lateralized brain function in clinical populations has been to examine the relative proportion of EEG alpha activity (8-12 Hz) in each hemisphere (i.e., alpha asymmetry). Increased rightward alpha…

Hale, T. Sigi; Smalley, Susan L.; Hanada, Grant; Macion, James; McCracken, James T.; McGough, James J.; Loo, Sandra K.

2009-01-01

308

Effectiveness of Alpha Biofeedback Therapy: Negative Results.  

ERIC Educational Resources Information Center

Assessed the utility of alpha biofeedback training in the treatment of patients (N=66). Biofeedback and placebo biofeedback groups were given alpha or mock-alpha training sessions. Improvement on 54 variables was compared to that of no-treatment controls. Only a chance number of significant changes appeared among the groups. (Author)

Watson, Charles G.; Herder, Joseph

1980-01-01

309

Thermoelectric Transport Coefficients in Correlated Condensed Matter  

NASA Astrophysics Data System (ADS)

We present a recently developed formalism for computing thermoelectric transport coefficients for standard models of correlated matter, such as the Hubbard and the t-J model. Successful predictions of this method in the context of the Hall constant are noted. This success helps to motivate the extension to the Seebeck coefficient, the Lorentz number L, and the figure of merit Z T, in terms of novel equal time correlation functions of two new fundamental operators, the thermal operator xxcirc and the thermoelectric operator xxcirc. Along the way, we uncover a new sum rule for the dynamical thermal conductivity for many standard models, precisely analogous to the f-sum rule for the electrical conductivity. Also along the way, we throw light on Lord Kelvin's early ideas on reciprocity, worked out within the context of equilibrium thermodynamics. The precise connection between Kelvin's formulation, and the later and more rigorous formulation of Onsager is commented upon. The new formalism is tested in simple settings and recent computational results are displayed for testing the frequency dependence of these variables in certain standard models. Close agreement with existing transport experiments on sodium cobaltates Na.68Co O2 in the Curie Weiss phase is found. Finally some new predictions are made regarding triangular lattice systems, motivated by the sodium cobaltate system.

Shastry, Sriram

2008-03-01

310

H2 Sticking Coefficients On Interstellar Grains  

NASA Astrophysics Data System (ADS)

Formation of H2 in interstellar gas occurs primarily via surface reactions on grains. A key parameter in determining the efficiency of H2 formation is the probability for H to stick to the surface. Once H2 is formed it may return to the surface and participate in further reactive processes. However, little is known about the sticking probability of H2 on grains. Simulations of the sticking coefficient for molecular hydrogen on the icy mantles of interstellar dust using a model based on classical molecular dynamics (MD) are being developed. The current study is on a simulated surface of amorphous ice with molecular hydrogen incident on the surface with different velocities. After a series of MD runs with different set of initial conditions based on the observed and known interstellar dust and gas temperatures, the sticking coefficient is then calculated as a function of the gas and dust temperatures. Preliminary results of these simulations will be presented at the meeting. This project is supported by NASA grant NNG06GJ11G from the Astrophysics Theory Program

Veeraghattam, Vijay; Takahashi, J.; Lewis, S. P.; Stancil, P. C.

2008-05-01

311

Fast computation of local correlation coefficients  

NASA Astrophysics Data System (ADS)

This paper presents an acceleration method, using both algorithmic and architectural means, for fast calculation of local correlation coefficients, which is a basic image-based information processing step for template or pattern matching, image registration, motion or change detection and estimation, compensation of changes, or compression of representations, among other information processing objectives. For real-time applications, the complexity in arithmetic operations as well as in programming and memory access latency had been a divisive issue between the so-called correction-based methods and the Fourier domain methods. In the presented method, the complexity in calculating local correlation coefficients is reduced via equivalent reformulation that leads to efficient array operations or enables the use of multi-dimensional fast Fourier transforms, without losing or sacrificing local and non-linear changes or characteristics. The computation time is further reduced by utilizing modern multi-core architectures, such as the Sony-Toshiba-IBM Cell processor, with high processing speed and low power consumption.

Sun, Xiaobai; Pitsianis, Nikos P.; Bientinesi, Paolo

2008-08-01

312

Iconic feature registration with sparse wavelet coefficients.  

PubMed

With the growing acceptance of nonrigid registration as a useful tool to perform clinical research, and in particular group studies, the storage space needed to hold the resulting transforms is deemed to become a concern for vector field based approaches, on top of the traditional computation time issue. In a recent study we lead, which involved the registration of more than 22,000 pairs of T1 MR volumes, this constrain appeared critical indeed. In this paper, we propose to decompose the vector field on a wavelet basis, and let the registration algorithm minimize the number of non-zero coefficients by introducing an L1 penalty. This enables a sparse representation of the vector field which, unlike parametric representations, does not confine the estimated transform into a small parametric space with a fixed uniform smoothness : nonzero wavelet coefficients are optimally distributed depending on the data. Furthermore, we show that the iconic feature registration framework allows to embed the non-differentiable L1 penalty into a C1 energy that can be efficiently minimized by standard optimization techniques. PMID:17354833

Cathier, Pascal

2006-01-01

313

Dispersion coefficients for alkali-metal diatoms  

SciTech Connect

The knowledge of the long-range interaction between atoms and molecules is of fundamental importance for low-energy and low-temperature collisions. The electrostatic interaction between the charge distributions of two ground-state alkali-metal atoms can be expanded in powers of 1/R, the internuclear distance. The coefficients corresponding to the expansion powers of R{sup -6}, R{sup -8}, and R{sup -10} are calculated exactly using a numerical technique originally developed for determining resonance profile near an absorption line. These coefficients are evaluated by integrating the dynamic electric multipole polarizabilities at imaginary frequencies which are in turn obtained by solving two coupled inhomogeneous differential equations. Highly accurate one-electron model potentials are developed to represent the motion of the valence electron in the field of the closed alkali positive ion core. The numerical results for the constants C{sub 6}, C{sub 8}, and C{sub 10} for the homo- and hetero-nuclear alkai diatoms are compared with other calculations.

Dalgarno, A.; Marinescu, M.; Sadeghpour, H.R. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

1993-05-01

314

Virial coefficients of Lennard-Jones mixtures.  

PubMed

We report results of calculations of the second through sixth virial coefficients for four prototype Lennard-Jones (LJ) mixtures that have been the subject of previous studies in the literature. Values are reported for temperatures ranging from T=0.6 to T=10.0, where here the temperature is given units of the LJ energy parameter of one of the components. Thermodynamic stability of the mixtures is studied using the virial equation of state (VEOS) with the calculated coefficients, with particular focus on characterizing the vapor-liquid critical behavior of the mixtures. For three of the mixtures, vapor-liquid coexistence and critical data are available for comparison at only one temperature, while for the fourth we can compare to a critical line. We find that the VEOS provides a useful indication of the presence and location of critical behavior, although in some situations we find need to consider "near-miss" critical behavior, where the classical conditions of criticality are nearly but not exactly satisfied. PMID:19530759

Schultz, Andrew J; Kofke, David A

2009-06-14

315

Virial coefficients of Lennard-Jones mixtures  

NASA Astrophysics Data System (ADS)

We report results of calculations of the second through sixth virial coefficients for four prototype Lennard-Jones (LJ) mixtures that have been the subject of previous studies in the literature. Values are reported for temperatures ranging from T=0.6 to T=10.0, where here the temperature is given units of the LJ energy parameter of one of the components. Thermodynamic stability of the mixtures is studied using the virial equation of state (VEOS) with the calculated coefficients, with particular focus on characterizing the vapor-liquid critical behavior of the mixtures. For three of the mixtures, vapor-liquid coexistence and critical data are available for comparison at only one temperature, while for the fourth we can compare to a critical line. We find that the VEOS provides a useful indication of the presence and location of critical behavior, although in some situations we find need to consider ``near-miss'' critical behavior, where the classical conditions of criticality are nearly but not exactly satisfied.

Schultz, Andrew J.; Kofke, David A.

2009-06-01

316

The Convergence Coefficient across Political Systems  

PubMed Central

Formal work on the electoral model often suggests that parties or candidates should locate themselves at the electoral mean. Recent research has found no evidence of such convergence. In order to explain nonconvergence, the stochastic electoral model is extended by including estimates of electoral valence. We introduce the notion of a convergence coefficient, c. It has been shown that high values of c imply that there is a significant centrifugal tendency acting on parties. We used electoral surveys to construct a stochastic valence model of the the elections in various countries. We find that the convergence coefficient varies across elections in a country, across countries with similar regimes, and across political regimes. In some countries, the centripetal tendency leads parties to converge to the electoral mean. In others the centrifugal tendency dominates and some parties locate far from the electoral mean. In particular, for countries with proportional electoral systems, namely, Israel, Turkey, and Poland, the centrifugal tendency is very high. In the majoritarian polities of the United States and Great Britain, the centrifugal tendency is very low. In anocracies, the autocrat imposes limitations on how far from the origin the opposition parties can move.

Schofield, Norman

2013-01-01

317

Halomethyl-Metal Compounds. Xli. Phenyl(Alpha, alpha-Dichlorobenzyl)Mercury: A Phenylchlorocarbene Precursor.  

National Technical Information Service (NTIS)

Phenyl(alpha, alpha-dichlorobenzyl)mercury has been prepared via alpha, alpha-dichlorobenzyllithium. It was found to be unstable to heat and to moisture, its hydrolysis giving benzene, benzoic acid and elemental mercury. Thermolysis of this mercurial in t...

D. Seyferth D. C. Mueller

1970-01-01

318

Trace-Element Diffusion Coefficients in Olivine  

NASA Astrophysics Data System (ADS)

We have undertaken chemical diffusion experiments at 1300°C to determine both crystal/melt partition coefficients and diffusion coefficients for a wide range of trace elements in forsteritic olivine. Experiments were conducted at 1 atm under controlled fO2 for up to 25 days using synthetic melts made to a composition in equilibrium with olivine for major elements, and doped with selected trace elements. The melt was put into a 5 mm diameter cylindrical hole in gem quality San Carlos olivine crystals drilled paralell to the a axis. Diffusion profiles were obtained both for trace elements that were added to the starting material and diffuse into the olivine, and also for several trace elements present at natural abundances in the olivine that diffuse out. The profiles were measured across sections perpendicular to crystal/melt boundary at a variety of crystallographic orientations (confirmed by EBSD) by laser-ablation ICP-MS. A thin laser slit oriented parallel to the crystal/melt interface was traversed from the melt through the crystal. Element concentrations were fitted to the diffusion equation to obtain both diffusion coefficients and concentrations at the crystal/melt interface, and hence partition coefficients. Calculated diffusivities for many trace elements (Ca, REE, Y, Sc, V, Cr, Ni, Co, Mn, Na, Li, Be, Ti) are relatively fast (D = 10-16 to 10^{-13 m2/s at 1300°C). The diffusion of Li in olivine (approx. D = 10^{-15} m2/s) is only slightly slower than REEs and similar to divalent cations, in good agreement with inferences from zoning profiles in natural olivine [1]. This rate is considerably slower than for plagioclase and clinopyroxene [2], a result which has important implications for interpreting Li isotopic data from mantle-derived rocks. The fastest diffusing trace element we observe is Be. Applying our diffusion and partition coefficients to the model of Qin et al. [3], we calculate that the REEs of olivine-hosted melt inclusions in the mantle will extensively re-equilibrate with external magma in weeks (heavy REEs) to a few years (light REEs). These timescales are significantly shorter than the times estimated for the production and extraction of magma from the mantle or magma residence in the lower crust, implying anomalous melt inclusions are probably not a direct result of melting of heterogeneities in the mantle. Instead, anomalous melt inclusions likely form by assimilation processes shortly before eruption [4] and so may be useful monitors of such processes. Refs: [1] Parkinson et al., Abstract, Goldschmidt Conference 2006; [2] Coogan et al., EPSL 240, 415-424 (2005); [3] Qin et al. Am. Min. 77, 565-576 (1992); [4] Danyushevsky et al., J. Petrol. 45, 2531-2553 (2004).

Spandler, C.; O'Neill, H. S.

2006-12-01

319

Blackness coefficients, effective diffusion parameters, and control rod worths for thermal reactors  

SciTech Connect

Simple diffusion theory cannot be used to evaluate control rod worths in thermal reactors because of the strongly absorbing character of the control material. However, good results can be obtained from a diffusion calculation by representing the absorber slab by means of a suitable pair of internal boundary conditions, ..cap alpha.. and ..beta.., which are ratios of neutron flux to neutron current. Methods for calculating ..cap alpha.. and ..beta.. in the P/sub 1/, P/sub 3/, and P/sub 5/ approximations, with and without scattering, are presented. By appropriately weighting the fine-group blackness coefficients, broad group values, <..cap alpha..> and <..beta..>, are obtained. The technique is applied to the calculation of control rod worths of Cd, Ag-In-Cd, and Hf control elements. Results are found to compare very favorably with detailed Monte Carlo calculations. For control elements whose geometry does not permit a thin slab treatment, other methods are needed for determining the effective diffusion parameters. One such method is briefly discussed and applied to the calculation of control rod worths in the Ford Nuclear Reactor at the University of Michigan. Calculated and measured worths are found to be in good agreement.

Bretscher, M.M.

1984-09-01

320

Dihydro-alpha-lipoic acid has more potent cytotoxicity than alpha-lipoic acid  

Microsoft Academic Search

Alpha-lipoic acid has been shown to possess cancer-cell-killing activity via activation of the apoptosis pathway. In this\\u000a study, the cytotoxic activities of alpha-lipoic and dihydro-alpha-lipoic acid were compared in HL-60 cells. The cell-killing\\u000a activity of dihydro-alpha-lipoic acid was higher than that of alpha-lipoic acid. Both alpha-lipoic and dihydro-alpha-lipoic\\u000a acid induced caspase-3 cleavage and internucleosomal DNA fragmentation in treated cells. On

Masao Yamasaki; Akiko Kawabe; Kentaro Nishimoto; Harishkumar Madhyastha; Yoichi Sakakibara; Masahito Suiko; Takeaki Okamoto; Taiji Suda; Kenzo Uehira; Kazuo Nishiyama

2009-01-01

321

Alpha-plutonium's Grüneisen parameter.  

PubMed

Reported Grüneisen parameters ? of alpha-plutonium range from 3.0 to 9.6, which is remarkable because typical Grüneisen parameter uncertainty seldom exceeds ± 0.5. Our six new estimates obtained by different methods range from 3.2 to 9.6. The new estimates arise from Grüneisen's rule, from Einstein model and Debye model fits to low-temperature ?V/V, from the bulk modulus temperature dependence, from the zero-point-energy contribution to the bulk modulus, and from another Grüneisen relationship whereby ? is estimated from only the bulk modulus and volume changes with temperature (or pressure). We disregard several high estimates because of the itinerant-localized 5f-electron changes during temperature changes and pressure changes. Considering all these estimates, for alpha-plutonium, we recommend ? = 3.7 ± 0.4, slightly high compared with values for all elemental metals. PMID:21386421

Ledbetter, Hassel; Lawson, Andrew; Migliori, Albert

2010-04-28

322

Thermal Desorption Gas Chromatography and Positron Annihilation Spectroscopy Contribution to Alpha Decay Studies in Actinide-Doped Matrices  

Microsoft Academic Search

A thermal desorption system coupled with a gas analyzer has been adapted and nuclearized to investigate He behavior in actinide-doped samples used to simulate alpha decay aging. This technique widely used in standard laboratories allows measurements of the helium balance and reduced diffusion coefficients, and a preliminary evaluation of helium locations (related to defects and thermal annealing). In our system

Daniele Roudil; Christophe Jegou; Raphael Pik; Marie France Barthe; Michel Cuney; François Vella; Yves Pipon; Benjamin Folch; Veronique Broudic

2010-01-01

323

Thermal desorption gas chromatography and positron annihilation spectroscopy contribution to alpha decay studies in actinide-doped matrices  

Microsoft Academic Search

A thermal desorption system coupled with a gas analyzer has been adapted and nuclearized to investigate He behavior in actinide-doped samples used to simulate alpha decay aging. This technique widely used in standard laboratories allows measurements of the helium balance and reduced diffusion coefficients, and a preliminary evaluation of helium locations (related to defects and thermal annealing). In our system

D. Roudil; C. Jegou; R. Pik; M. F. Barthe; M. Cuney; F. Vella; Y. Pipon; B. Folch; V. Broudic

2009-01-01

324

Alpha-fetoprotein in Abortion  

Microsoft Academic Search

The clinical value of maternal serum alpha-fetoprotein (AFP) as a guide to the outcome of threatened abortion was assessed. After the thirteenth week of gestation, abortion occurred more frequently (10\\/12) in women with abnormal serum AFP levels than in those (2\\/12) whose AFP concentrations were within the normal range. Low levels were present in women with blighted ovum and high

Markku Seppälä; Erkki Ruoslahti

1972-01-01

325

The Alpha Magnetic Spectrometer (AMS)  

Microsoft Academic Search

The Alpha Magnetic Spectrometer (AMS) is a large acceptance (0.65srm2) detector designed to operate in the International Space Station (ISS) for three years. The purposes of the experiment are to search for cosmic antimatter and dark matter and to study the composition and energy spectrum of the primary cosmic rays. A “scaled-down” version has been flown on the Space Shuttle

J. Alcaraz; B. Alpat; G. Ambrosi; H. Anderhub; L. Ao; A. Arefiev; P. Azzarello; E. Babucci; L. Baldini; M. Basile; D. Barancourt; F. Barao; G. Barbier; G. Barreira; R. Battiston; R. Becker; U. Becker; L. Bellagamba; P. Bene; J. Berdugo; P. Berges; B. Bertucci; A. Biland; S. Bizzaglia; S. Blasko; G. Boella; M. Boschini; M. Bourquin; L. Brocco; G. Bruni; M. Buenerd; J. D. Burger; W. J. Burger; X. D. Cai; C. Camps; P. Cannarsa; M. Capell; D. Casadei; J. Casaus; G. Castellini; C. Cecchi; Y. H. Chang; H. F. Chen; H. S. Chen; Z. G. Chen; N. A. Chernoplekov; T. H. Chiueh; Y. L. Chuang; F. Cindolo; V. Commichau; A. Contin; P. Crespo; M. Cristinziani; J. P. da Cunha; T. S. Dai; J. D. Deus; N. Dinu; L. Djambazov; I. DAntone; Z. R. Dong; P. Emonet; J. Engelberg; F. J. Eppling; T. Eronen; G. Esposito; P. Extermann; J. Favier; E. Fiandrini; P. H. Fisher; G. Fluegge; N. Fouque; Yu. Galaktionov; M. Gervasi; P. Giusti; D. Grandi; O. Grimm; W. Q. Gu; K. Hangarter; A. Hasan; V. Hermel; H. Hofer; M. A. Huang; W. Hungerford; M. Ionica; R. Ionica; M. Jongmanns; K. Karlamaa; W. Karpinski; G. Kenney; J. Kenny; W. Kim; A. Klimentov; R. Kossakowski; V. Koutsenko; M. Kraeber; G. Laborie; T. Laitinen; G. Lamanna; G. Laurenti; A. Lebedev; S. C. Lee; G. Levi; P. Levtchenko; C. L. Liu; H. T. Liu; I. Lopes; G. Lu; Y. S. Lu; K. Lübelsmeyer; D. Luckey; W. Lustermann; A. Margotti; F. Mayet; R. R. McNeil; B. Meillon; M. Menichelli; A. Mihul; A. Mourao; A. Mujunen; F. Palmonari; A. Papi; I. H. Park; M. Pauluzzi; F. Pauss; E. Perrin; A. Pesci; A. Pevsner; M. Pimenta; V. Plyaskin; V. Pojidaev; V. Postolache; N. Produit; P. G. Rancoita; D. Rapin; F. Raupach; D. Ren; Z. Ren; M. Ribordy; J. P. Richeux; E. Riihonen; J. Ritakari; U. Roeser; C. Roissin; R. Sagdeev; G. Sartorelli; A. Schultz von Dratzig; G. Schwering; G. Scolieri; E. S. Seo; V. Shoutko; E. Shoumilov; R. Siedling; D. Son; T. Song; M. Steuer; G. S. Sun; H. Suter; X. W. Tang; Samuel C. C. Ting; S. M. Ting; M. Tornikoski; J. Torsti; J. Tr umper; J. Ulbricht; S. Urpo; I. Usoskin; E. Valtonen; J. Vandenhirtz; F. Velcea; E. Velikhov; B. Verlaat; I. Vetlitsky; F. Vezzu; J. P. Vialle; G. Viertel; D. Vite; H. Von Gunten; S. Waldmeier Wicki; W. Wallraff; B. C. Wang; J. Z. Wang; Y. H. Wang; K. Wiik; C. Williams; S. X. Wu; P. C. Xia; J. L. Yan; L. G. Yan; C. G. Yang; M. Yang; S. W. Ye; P. Yeh; Z. Z. Xu; H. Y. Zhang; Z. P. Zhang; D. X. Zhao; G. Y. Zhu; W. Z. Zhu; H. L. Zhuang; A. Zichichi; B. Zimmermann

2002-01-01

326

The Alpha 21264 microprocessor architecture  

Microsoft Academic Search

The 21264 is the third generation Alpha microprocessor from Compaq Computer (formerly Digital Equipment) Corporation. This microprocessor achieves the industry-leading performance levels of 30+ Specint95 and 50+ Specfp95. In addition to the aggressive 600 MHz cycle time in a 0.35 ?m CMOS process, there are also many architectural features that enable the outstanding performance level of the 21264. This paper

R. E. Kessler; E. J. McLellan; D. A. Webb

1998-01-01

327

Studies on DNA replication in vitro by DNA polymerase-. alpha. /primase complex from embryonic chicken brain  

SciTech Connect

DNA polymerase - {alpha} activity, characterized by its sensitivity to N-ethylmaleimide, high sedimentation coefficient, and acidic isoelectric point was found to decline with increasing embryonic age. Primase activity, the enzyme responsible for the initiation of DNA synthesis, was found to co-sediment with DNA polymerase - {alpha} activity on a continuous glycerol velocity gradient. Of all the single-stranded DNA templates tested, primase activity was found to be maximally active with poly dC. In the presence of ({alpha}-{sup 32}P) GTP, primase activity was found to catalyze the formation of an alkali-labile oligoriboguanylate, 15-20 nucleotides long. The chain length of the products were not altered by the presence or absence of dGTP. Primase activity was not inhibited by a high concentration of {alpha}- amanitin. Consistent with the finding of a decline of the activity level of DNA polymerase - {alpha}, the level of DNA polymerase - {alpha} antigen was also found to decrease with embryonic age, as evidenced by ELISA with a non-neutralizing monoclonal antibody, SJK 237-71.

Ray, S.

1988-01-01

328

Alpha voltaic batteries and methods thereof  

NASA Technical Reports Server (NTRS)

An alpha voltaic battery includes at least one layer of a semiconductor material comprising at least one p/n junction, at least one absorption and conversion layer on the at least one layer of semiconductor layer, and at least one alpha particle emitter. The absorption and conversion layer prevents at least a portion of alpha particles from the alpha particle emitter from damaging the p/n junction in the layer of semiconductor material. The absorption and conversion layer also converts at least a portion of energy from the alpha particles into electron-hole pairs for collection by the one p/n junction in the layer of semiconductor material.

Raffaelle, Ryne P. (Inventor); Jenkins, Phillip (Inventor); Wilt, David (Inventor); Scheiman, David (Inventor); Chubb, Donald (Inventor); Castro, Stephanie (Inventor)

2011-01-01

329

Alpha-1 antitrypsin deficiency, a corporate perspective.  

PubMed

Best-in-class systems have evolved among alpha-1 antitrypsin (AAT) producers, specialty pharmacies and the Alpha-1 Foundation and AlphaNet patient groups. The Genetic Alliance, NORD and other independent parties have recognized the benefits regarding public policy, patient advocacy, medical research, medication adherence, patient identification and health outcomes. Driving the next quantum leap in disease state management for Alpha-1 patients will require strong leadership from both industry and patient groups. Six initiatives are suggested that will sustain best-in-class approaches to identify, treat and even cure Alpha-1 patients. PMID:23527855

Stern, Lawrence D

2013-03-01

330

alpha-clustering and absolute alpha-decay widths in spherical nuclei  

Microsoft Academic Search

The absolute alpha-decay in 212Po is calculated using a shell-model description of the alpha-particle formation. It is found that high-lying shell-model configurations greatly enhance both the alpha-clustering features and the calculated alpha-decay width. The interaction among the nucleons that form the alpha-particle is included through correlated two-particle states.

Gordana Dodig-Crnkovic; F. A. Janouch; R. J. Liotta

1984-01-01

331

THE LYMAN ALPHA REFERENCE SAMPLE: EXTENDED LYMAN ALPHA HALOS PRODUCED AT LOW DUST CONTENT  

SciTech Connect

We report on new imaging observations of the Lyman alpha emission line (Ly{alpha}), performed with the Hubble Space Telescope, that comprise the backbone of the Lyman alpha Reference Sample. We present images of 14 starburst galaxies at redshifts 0.028 < z < 0.18 in continuum-subtracted Ly{alpha}, H{alpha}, and the far ultraviolet continuum. We show that Ly{alpha} is emitted on scales that systematically exceed those of the massive stellar population and recombination nebulae: as measured by the Petrosian 20% radius, R{sub P20}, Ly{alpha} radii are larger than those of H{alpha} by factors ranging from 1 to 3.6, with an average of 2.4. The average ratio of Ly{alpha}-to-FUV radii is 2.9. This suggests that much of the Ly{alpha} light is pushed to large radii by resonance scattering. Defining the Relative Petrosian Extension of Ly{alpha} compared to H{alpha}, {xi}{sub Ly{alpha}} = R {sup Ly{alpha}}{sub P20}/R {sup H{alpha}}{sub P20}, we find {xi}{sub Ly{alpha}} to be uncorrelated with total Ly{alpha} luminosity. However, {xi}{sub Ly{alpha}} is strongly correlated with quantities that scale with dust content, in the sense that a low dust abundance is a necessary requirement (although not the only one) in order to spread Ly{alpha} photons throughout the interstellar medium and drive a large extended Ly{alpha} halo.

Hayes, Matthew [Universite de Toulouse, UPS-OMP, IRAP, Toulouse (France); Oestlin, Goeran; Duval, Florent; Guaita, Lucia; Melinder, Jens; Sandberg, Andreas [Department of Astronomy, Oskar Klein Centre, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm (Sweden); Schaerer, Daniel [CNRS, IRAP, 14, avenue Edouard Belin, F-31400 Toulouse (France); Verhamme, Anne; Orlitova, Ivana [Geneva Observatory, University of Geneva, 51 Chemin des Maillettes, CH-1290 Versoix (Switzerland); Mas-Hesse, J. Miguel; Oti-Floranes, Hector [Centro de Astrobiologia (CSIC-INTA), Departamento de Astrofisica, POB 78, 28691 Villanueva de la Canada (Spain); Adamo, Angela [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Atek, Hakim [Laboratoire d'Astrophysique, Ecole Polytechnique Federale de Lausanne (EPFL), Observatoire, CH-1290 Sauverny (Switzerland); Cannon, John M. [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); Herenz, E. Christian [Leibniz-Institut fuer Astrophysik (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Kunth, Daniel [Institut d'Astrophysique de Paris, UMR 7095 CNRS and UPMC, 98 bis Bd Arago, F-75014 Paris (France); Laursen, Peter, E-mail: matthew@astro.su.se [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark)

2013-03-10

332

Modeling the alpha IIb beta 3 integrin solution conformation.  

PubMed Central

The alpha IIb beta 3 platelet integrin is the prototypical member of a widely distributed class of transmembrane receptors formed by the noncovalent association of alpha and beta subunits. Electron microscopic (EM) images of the alpha IIb beta 3 complex show an asymmetric particle with a globular domain from which two extended regions protrude to contact the lipid bilayer. Distance constraints provided by disulfide bond patterns, epitope mapping, and ligand mimetic cross-linking studies rather suggest a somewhat more compact conformation for the alpha IIb beta 3 complex. We have studied the shape of detergent-solubilized alpha IIb beta 3 by employing a low-resolution modeling procedure in which each polypeptide has been represented as an array of interconnected, nonoverlapping spheres (beads) of various sizes. The number, size, and three-dimensional relationships among the beads were defined either solely by dimensions obtained from published EM images of integrin receptors (EM models, 21 beads), or solely by interdomain constraints derived from published biochemical data (biochemical model, 37 beads). Interestingly, although no EM data were employed in its construction, the resulting overall shape of the biochemical model was still compatible with the EM data. Both kinds of models were then evaluated for their calculated solution properties. The more elongated EM models have diffusion and sedimentation coefficients that differ, at best, by +2% and -18% from the experimental values, determined, respectively, in octyl glucoside and Triton X-100. On the other hand, the parameters calculated for the more compact biochemical model showed a more consistent agreement with experimental values, differing by -7% (octyl glucoside) to -6% (Triton X-100). Thus, it appears that using the biochemical constraints as a starting point has resulted in not only a more detailed model of the detergent-solubilized alpha IIb beta 3 complex, where the relative spatial location of specific domains the size of 5-10 kDa can be tentatively mapped, but in a model that can also reconcile the electron microscopy with the biochemical and the solution data.

Rocco, M.; Spotorno, B.; Hantgan, R. R.

1993-01-01

333

The large coefficient problem; can we make sense out of QCD perturbation theory  

SciTech Connect

There is the possibility of an impending crisis looming on the horizon for QCD. The problem is that in many processes, large coefficients arise in the perturbation series expansion leading to serious uncertainties concerning its predictive power. Until recently most of the examples of such a phenomenon occurred in the calculation of decay rates. These were, by and large, either ignored or dismissed using possible scheme-dependence arguments as a way out. However, more recently a calculation of the 3-loop contribution to the total e{sup +}e{sup -} annihilation cross-section was performed which gave an enormous coefficient of the order of 50 times that of the 2-loop term. If correct, this would imply that the 3-loop contribution actually exceeds that of the 2-loop Thus, from a conservative viewpoint, the validity of the perturbation series expansion as an estimate for the total e{sup +}e{sup -} cross-section is called into question. Since this process has played a key role in the development and understanding of QCD and since, in many ways, it is one of the cleanest methods for extracting {alpha}{sub s} the problem can no longer be avoided. Furthermore, there is no reason to doubt that this problem should occur in all physical processes. Coming to grips with it is, of course, not only important for testing QCD but also for extracting fundamental quantities such as {alpha}{sub s}. Clearly one needs to understand the nature and origin of such large coefficients before one can confidently continue to use perturbative estimates. The purpose of this talk is to focus on these problems. I shall first review the experimental situation with some examples illustrating the problem. I shall then discuss various general components and properties of perturbation theory before attempting to give a possible resolution of the problem. 18 refs., 5 figs.

West, G.B.

1989-01-01

334

Embryonic cardiomyocyte hypoplasia and craniofacial defects in G alpha q/G alpha 11-mutant mice.  

PubMed Central

Heterotrimeric G proteins of the Gq class have been implicated in signaling pathways regulating cardiac growth under physiological and pathological conditions. Knockout mice carrying inactivating mutations in both of the widely expressed G alpha q class genes, G alpha q and G alpha 11, demonstrate that at least two active alleles of these genes are required for extrauterine life. Mice carrying only one intact allele [G alpha q(-/+);G alpha 11(-/-) or G alpha q(-/-);G alpha 11(-/+)] died shortly after birth. These mutants showed a high incidence of cardiac malformation. In addition, G alpha q(-/-);G alpha 11(-/+) newborns suffered from craniofacial defects. Mice lacking both G alpha q and G alpha 11 [G alpha q(-/-);G alpha 11(-/-)] died at embryonic day 11 due to cardiomyocyte hypoplasia. These data demonstrate overlap in G alpha q and G alpha 11 gene functions and indicate that the Gq class of G proteins plays a crucial role in cardiac growth and development.

Offermanns, S; Zhao, L P; Gohla, A; Sarosi, I; Simon, M I; Wilkie, T M

1998-01-01

335

QRS detection based on wavelet coefficients.  

PubMed

Electrocardiogram (ECG) signal processing and analysis provide crucial information about functional status of the heart. The QRS complex represents the most important component within the ECG signal. Its detection is the first step of all kinds of automatic feature extraction. QRS detector must be able to detect a large number of different QRS morphologies. This paper examines the use of wavelet detail coefficients for the accurate detection of different QRS morphologies in ECG. Our method is based on the power spectrum of QRS complexes in different energy levels since it differs from normal beats to abnormal ones. This property is used to discriminate between true beats (normal and abnormal) and false beats. Significant performance enhancement is observed when the proposed approach is tested with the MIT-BIH arrhythmia database (MITDB). The obtained results show a sensitivity of 99.64% and a positive predictivity of 99.82%. PMID:22296976

Zidelmal, Zahia; Amirou, Ahmed; Adnane, Mourad; Belouchrani, Adel

2012-09-01

336

Implicit Extrapolation Methods for Variable Coefficient Problems  

NASA Technical Reports Server (NTRS)

Implicit extrapolation methods for the solution of partial differential equations are based on applying the extrapolation principle indirectly. Multigrid tau-extrapolation is a special case of this idea. In the context of multilevel finite element methods, an algorithm of this type can be used to raise the approximation order, even when the meshes are nonuniform or locally refined. Here previous results are generalized to the variable coefficient case and thus become applicable for nonlinear problems. The implicit extrapolation multigrid algorithm converges to the solution of a higher order finite element system. This is obtained without explicitly constructing higher order stiffness matrices but by applying extrapolation in a natural form within the algorithm. The algorithm requires only a small change of a basic low order multigrid method.

Jung, M.; Ruede, U.

1996-01-01

337

Partition Coefficients at High Pressure and Temperature  

NASA Astrophysics Data System (ADS)

Differentiation of terrestrial planets includes separation of a metallic core and possible later fractionation of mineral phases within either a solid or molten mantle (Figure 1). Lithophile and siderophile elements can be used to understand these two different physical processes, and ascertain whether they operated in the early Earth. The distribution of elements in planets can be understood by measuring the partition coefficient, D (ratio of concentrations of an element in different phases (minerals, metals, or melts)). (14K)Figure 1. Schematic cross-section through the Earth, showing: (a) an early magma ocean stage and (b) a later cool and differentiated stage. The siderophile elements (iron-loving) encompass over 30 elements and are defined as those elements for which D(metal/silicate)>1, and are useful for deciphering the details of core formation. This group of elements is commonly broken up into several subclasses, including the slightly siderophile elements (1104). Because these three groups encompass a wide range of partition coefficient values, they can be very useful in trying to determine the conditions under which metal may have equilibrated with the mantle (or a magma ocean). Because metal and silicate may equilibrate by several different mechanisms, such as at the base of a deep magma ocean, or as metal droplets descend through a molten mantle, partition coefficients can potentially shed light on which mechanism may be most important, thus linking the physics and chemistry of core formation. In this chapter, we summarize metal/silicate partitioning of siderophile elements and show how they may be used to understand planetary core formation.Once a planet is differentiated into core and mantle, a mantle will cool during convection, and can start in either a molten or solid state, depending upon the initial thermal conditions. If hot enough, minerals will crystallize from a molten mantle, and become entrained in the convecting melt, or eventually settle out at the bottom. The entrainment and settling process has been studied in detail (e.g., Tonks and Melosh, 1990), and is a potential mechanism for differentiation between the deep and shallow parts of Earth's mantle. The lithophile elements, those elements that have D(metal/silicate) <1, fall into many different subclasses and all hold information about the deep mineral structure of the mantle. Rare-earth elements (REEs) have proven to be useful: europium anomalies have helped elucidate the role of plagioclase in lunar crust formation (e.g., Schnetzler and Philpotts, 1971; Weill et al., 1974), and LREE/HREE depletion and enrichment are indicators of partial melting in the presence of garnet in the mantle. High-field-strength elements (HFSEs) - niobium, zirconium, tantalum, and hafnium - are all refractory and hence more resilient to fractionation processes such as volatility or condensation. They also have an affinity for ilmenite and rutile, and can explain differences between lunar and martian samples as well as features of Earth's continental crust ( Taylor and McLennan, 1985). Alkaline-earth and alkaline elements include rubidium, strontium, barium, potassium, caesium, and calcium, some of which are involved in radioactive decay couples, e.g., Rb-Sr and K-Ar. The latter is important in understanding the contribution of radioactive decay to planetary heat production, and potential deep sources of radiogenic argon (see Chapter 2.06). Rubidium and potassium are further useful as tracers of hydrous phases such as mica and amphibole. Possible fractionation of any of these elements from chondritic abundances (see Chapter 2.01) can be assessed with the knowledge of partition coefficients. In this chapter we summarize our understanding of mineral/melt fractionation of minor and trace elements at high pressures and temperatures and discuss the implications for mantle differentiation.

Righter, K.; Drake, M. J.

2003-12-01

338

Molar extinction coefficients of some fatty acids  

NASA Astrophysics Data System (ADS)

The attenuation of gamma rays in some fatty acids, viz. formic acid (CH 2O 2), acetic acid (C 2H 4O 2), propionic acid (C 3H 6O 2), butyric acid (C 4H 8O 2), n-hexanoic acid (C 6H 12O 2), n-caprylic acid (C 8H 16O 2), lauric acid (C 12H 24O 2), myristic acid (C 14H 28O 2), palmitic acid (C 16H 32O 2), oleic acid (C 18H 34O 2) and stearic acid (C 18H 36O 2), has been measured at the photon energies 81, 356, 511, 662, 1173 and 1332 keV. Experimental values for the molar extinction coefficient, the effective atomic number and the electron density have been derived and compared with theoretical calculations. There is good agreement between experiment and theory.

Sandhu, G. K.; Singh, Kulwant; Lark, B. S.; Gerward, L.

2002-10-01

339

Transport Coefficients in weakly compressible turbulence  

NASA Technical Reports Server (NTRS)

A theory of transport coefficients in weakly compressible turbulence is derived by applying Yoshizawa's two-scale direct interaction approximation to the compressible equations of motion linearized about a state of incompressible turbulence. The result is a generalization of the eddy viscosity representation of incompressible turbulence. In addition to the usual incompressible eddy viscosity, the calculation generates eddy diffusivities for entropy and pressure, and an effective bulk viscosity acting on the mean flow. The compressible fluctuations also generate an effective turbulent mean pressure and corrections to the speed of sound. Finally, a prediction unique to Yoshizawa's two-scale approximation is that terms containing gradients of incompressible turbulence quantities also appear in the mean flow equations. The form these terms take is described.

Rubinstein, Robert; Erlebacher, Gordon

1996-01-01

340

Ultrarelativistic transport coefficients in two dimensions  

NASA Astrophysics Data System (ADS)

We compute the shear and bulk viscosities, as well as the thermal conductivity, of an ultrarelativistic fluid obeying the relativistic Boltzmann equation in 2 + 1 space-time dimensions. The relativistic Boltzmann equation is taken in the single relaxation time approximation, based on two approaches, the first due to Marle and using the Eckart decomposition, and the second proposed by Anderson and Witting and using the Landau-Lifshitz decomposition. In both cases, the local equilibrium is given by a Maxwell-Jüttner distribution. It is shown that, apart from slightly different numerical prefactors, the two models lead to a different dependence of the transport coefficients on the fluid temperature, quadratic and linear, for the case of Marle and Anderson-Witting, respectively. However, by modifying the Marle model according to the prescriptions given in previous results, it is found that the temperature dependence becomes the same as for the Anderson-Witting model.

Mendoza, M.; Karlin, I.; Succi, S.; Herrmann, H. J.

2013-02-01

341

Asymptotic normalization coefficients from ab initio calculations  

NASA Astrophysics Data System (ADS)

We present calculations of asymptotic normalization coefficients (ANCs) for one-nucleon removals from nuclear states of mass numbers 3?A?9. Our ANCs were computed from variational Monte Carlo solutions to the many-body Schrödinger equation with the combined Argonne v18 two-nucleon and Urbana IX three-nucleon potentials. Instead of computing explicit overlap integrals, we applied a Green function method that is insensitive to the difficulties of constructing and Monte Carlo sampling the long-range tails of the variational wave functions. This method also allows computation of the ANC at the physical separation energy, even when it differs from the separation energy for the Hamiltonian. We compare our results, which for most nuclei are the first ab initio calculations of ANCs, with existing experimental and theoretical results and discuss further possible applications of the technique.

Nollett, Kenneth M.; Wiringa, R. B.

2011-04-01

342

PPAR-alpha in cutaneous inflammation  

PubMed Central

Peroxisome proliferator-activated receptor (PPAR)-alpha is a fatty acid activated transcription factors that belongs to the nuclear hormone receptor family. Primarily PPAR-alpha serves as a lipid sensor. While PPAR-alpha controls enzymes from the lipid and glucose metabolism in the liver, heart and muscles, PPAR-alpha is also involved in skin homeostasis. PPAR-alpha controls keratinocyte proliferation/differentiation, contributes to wound healing and regulates skin inflammation. PPAR-alpha activation exerts anti-inflammatory effects in various skin conditions such as irritant and allergic contact dermatitis, atopic dermatitis and UV-induced erythema, rendering investigations into the functions of PPAR-alpha necessary to provide better understandings to treat many inflammatory skin disorders.

Schmuth, Matthias

2011-01-01

343

Improving the accuracy of aerosol extinction coefficient inversion  

NASA Astrophysics Data System (ADS)

This paper considers the relationship between the accuracy of aerosol extinction inversion and the boundary value, and derives a theoretical high-accuracy aerosol extinction coefficient inversion. Aerosol extinction coefficient profiles depend on the boundary value. The relationship function of the differential extinction coefficient and differential boundary value is expressed by a maximum value. The smaller the differential boundary value, the smaller the differential extinction coefficient. The clean atmosphere layer is easily found from the lidar range-corrected signal, and the extinction coefficient of the clean atmosphere layer can be obtained using the slope method. By relating the extinction coefficient of the clean atmosphere layer to the extinction coefficient profiles at different boundary values, an accurate aerosol extinction coefficient profile can be obtained.

Cao, Nianwen; Yang, Fengkai; Zhu, Cunxiong

2014-04-01

344

Flexoelectric and elastic coefficients of odd and even homologous bimesogens  

NASA Astrophysics Data System (ADS)

It is known that bimesogenic liquid crystals exhibit a marked “odd-even” effect in the flexoelastic ratio (the effective flexoelectric coefficient to the average elastic coefficient), with the ratio being higher for the “odd-spaced” bimesogens (those with an odd number of alkyl groups in the spacer chain) than their neighboring even-spaced counterparts. To determine the contribution of each property to the flexoelastic ratio, we present experimental results on the flexoelectric and elastic coefficients of two homologous nonsymmetric bimesogens which possess odd and even alkyl spacers. Our results show that, although there are differences in the flexoelectric coefficients, there are substantially larger differences in the effective elastic coefficient. Specifically, the odd bimesogen is found to have both a low splay elastic coefficient and a very low bend elastic coefficient which, when combined, results in a significantly lower effective elastic coefficient and consequently a higher flexoelastic ratio.

Atkinson, Katie L.; Morris, Stephen M.; Castles, Flynn; Qasim, Malik M.; Gardiner, Damian J.; Coles, Harry J.

2012-01-01

345

Octanol-Water Partition Coefficients by Capillary Electrophoresis.  

National Technical Information Service (NTIS)

We have investigated the use of capillary electrophoresis (CE) for the modeling of octanol-water partition coefficients. Reversed-phase liquid chromatography (RPLC) is likely the most used method for estimation of octanol-water partition coefficients, wit...

J. G. Dorsey

1996-01-01

346

Uniform diffraction coefficients of physical optics for impedance surfaces  

Microsoft Academic Search

Uniform diffraction coefficients of PO (physical optics) for impedance surfaces are derived, and accuracy is checked. These diffraction coefficients reveal that PO has no polarization conversion at SB\\/RB geometrical optics boundaries and this fact is numerically checked

M. Oodo; T. Murasaki; M. Ando

1993-01-01

347

Diffraction Coefficients for a Slot-Excited Conical Antenna.  

National Technical Information Service (NTIS)

First-order diffraction coefficients for a slot-excited conical antenna are calculated, beginning with integral expressions for the radiation field. Simple formulas based on these coefficients are presented for the radiation patterns that correctly reprod...

D. C. Pridmore-Brown

1971-01-01

348

Techniques for increasing throughput in HEVC transform coefficient coding  

NASA Astrophysics Data System (ADS)

Transform coefficient coding in HEVC encompasses the scanning patterns and the coding methods for the last significant coefficient, significance map, coefficient levels and sign data. Unlike H.264/AVC, HEVC has a single entropy coding mode based on the context adaptive binary arithmetic coding (CABAC) engine. Due to this, achieving high throughput for transform coefficient coding was an important design consideration. This paper analyzes the throughput of different components of transform coefficient coding with special emphasis on the explicit coding of the last significant coefficient position and high throughput binarization. A comparison with H.264/AVC transform coefficient coding is also presented, demonstrating that HEVC transform coefficient coding achieves higher average and worst case throughput.

Joshi, Rajan L.; Sole, Joel; Chen, Jianle; Chien, Wei-Jung; Karczewicz, Marta

2012-10-01

349

Coefficients of Fractional Parentage and Ll-Coupling.  

National Technical Information Service (NTIS)

The coefficients of fractional parentage required for making computations in the LL-coupling scheme for equivalent electron configurations of d and f electrons are shown to be directly derivable from existing tabulations of coefficients of fractional pare...

B. G. Wybourne

1968-01-01

350

Temperature Coefficient of Electrode Electric Tension and Activity Coefficients of Individual Ionic Species.  

National Technical Information Service (NTIS)

The electrodes Pt-H2/H(+)Br(-) and Ag/AgBr/Br(-)K(+) were investigated for the true temperature coefficient of their electric tension. The measurement at 25C and 35C were extended over the concentration range from about 0.1m down to about 0.001. The poten...

A. Marconi B. Struck C. Palma G. Milazzo M. E. Weill

1972-01-01

351

Asymptotics of Raynal-Revai coefficients at large hypermomentum  

NASA Astrophysics Data System (ADS)

The Raynal-Revai coefficients are studied as the Wigner D functions of O(6) group generated by the kinematical rotation of two reduced Jacobi vectors in six-dimensional three-body space. These coefficients are represented as one-dimensional integrals with kernels equal to double sums of the Clebsh-Gordan coefficients and associated Legendre polynomials. Using this representation we derive the asymptotics of the Raynal-Revai coefficients at large values of the hypermomentum.

Pupyshev, V. V.

2009-05-01

352

WWW-Based Fourier coefficient database - A status report  

NASA Astrophysics Data System (ADS)

The status of the WWW-based Fourier Coefficient web site is presented. Currently the database has coefficients for not only galactic field variables, but also those found in globular clusters and other galaxies, including the Magellanic Clouds. The database can be used to show various correlations between physical characteristics of the stars and the coefficients, as well as inter-relationships between the coefficients them-selves. The database is accessible at http://nitro9.earth.uni.edu/fourier/

Morgan, Siobahn M.

2004-05-01

353

X-ray analysis of alpha mercuric iodide crystal structure and processing effects  

SciTech Connect

X-ray topography and rocking curve experiments were performed on {alpha}-mercuric iodide samples. As-grown crystals were examined for Intrinsic defects and crystallinity. Orientation of certain defects depends on the direction of crystal growth. The propagation of as-grown crystalline features was documented. The extent of crystal damage Introduced during various steps of device fabrication such as sawing, polishing, etching and contact deposition was explored. Coefficients of linear thermal expansion of {alpha}{sub 33} = 54 {plus_minus} 5{center_dot}10{sup {minus}6}/{degrees}C along the tetragonal c-axis, [001] direction and {alpha}{sub 11} = 11 {plus_minus} 4{center_dot}10{sup {minus}6}/{degrees}C in the [100] direction were measured.

Keller, L. [CAMET Research, Inc., Goleta, CA (United States); Wang, E.X.; Cheng, A.Y. [EG and G Energy Measurements, Inc., Goleta, CA (United States). Santa Barbara Operations

1993-07-01

354

Coupling coefficient of spiral resonators used for wireless power transfer  

Microsoft Academic Search

Coupling coefficient between two spiral resonators used for wireless power transfer is studied. It is pointed out that spiral resonators have different coupling coefficient corresponding to the mirror co-directional or inversely wound configurations alignment. The reason is clarified by calculating the coupling coefficient separately as the electric and magnetic parts. Helical resonators are also studied for comparison showing negligible difference

Ikuo Awai; Yanjun Zhang; Takuya Komori; Toshio Ishizaki

2010-01-01

355

Measurement of the heat transfer coefficient for walls  

Microsoft Academic Search

A test set-up was developed for the determination of the external heat transfer coefficient of walls under actual outdoor conditions. The set-up was used to measure the convective heat transfer coefficient for the central region of a vertical wall. Outdoor tests were carried out under a wide range of conditions and the heat transfer coefficient was correlated with wind speed.

S. E. G. Jayamaha; N. E. Wijeysundera; S. K. Chou

1996-01-01

356

On approximating line spectral frequencies to LPC cepstral coefficients  

Microsoft Academic Search

We propose an approximation of the line spectral frequencies (LSFs) to the LPC cepstral coefficients (LPCCs). A direct relationship between LPCC and LSF is derived, and new parameters, named pseudo-cepstral coefficients, are obtained by reducing some factors in the relationship. We also address the statistical properties of the pseudo-cepstral coefficients and show their useful application to speech recognition

Hong Kook Kim; Seung Ho Choi; Hwang Soo Lee

2000-01-01

357

Likelihood-based inference for genetic correlation coefficients  

Microsoft Academic Search

We review Wright's original definitions of the genetic correlation coefficients FST, FIT, and FIS, pointing out ambiguities and the difficulties that these have generated. We also briefly survey some subsequent approaches to defining and estimating the coefficients. We then propose a general framework in which the coefficients are defined, their properties established, and likelihood-based inference implemented. Likelihood methods of inference

David J. Balding

2003-01-01

358

Review of analysis methods for rotating systems with periodic coefficients  

NASA Technical Reports Server (NTRS)

Two of the more common procedures for analyzing the stability and forced response of equations with periodic coefficients are reviewed: the use of Floquet methods, and the use of multiblade coordinate and harmonic balance methods. The analysis procedures of these periodic coefficient systems are compared with those of the more familiar constant coefficient systems.

Dugundji, J.; Wendell, J. H.

1981-01-01

359

Calculation of evaporative loss coefficients for thermal power plants  

Microsoft Academic Search

Evaporative loss coefficients are calculated for cooling the condensers of steam electric power plants. Models which simulate the cooling of such plants using cooling ponds, cooling towers, and once-through cooling are developed and applied at 230 locations within the contiguous U.S. Evaporative loss coefficients are calculated for 24 cooling configurations using mean monthly weather parameters. These coefficients are expressed in

Sonnichsen; J. C. Jr

1978-01-01

360

Synthesizer 1.0: a varying-coefficient meta-analytic tool.  

PubMed

Meta-analysis has become an indispensable tool for reaching accurate and representative conclusions about phenomena of interest within a research literature. However, in order for meta-analytic computations to provide accurate estimates of population parameters (e.g., a population correlation), underlying statistical models need to be both efficient and unbiased. Current fixed-effect (i.e., constant-coefficient) models that assume a common effect for all research results perform poorly under conditions of effect size heterogeneity, whereas current random-effects (i.e., random-coefficient) models require unrealistic assumptions about random sampling of observed effect sizes from a normally distributed superpopulation. This article describes a free statistical software tool that employs a varying-coefficient model recently proposed by Bonett (2008, 2009). The software (Synthesizer 1.0) employs procedures that do not require effect homogeneity or random sampling of effect sizes from a normal distribution. It may be used to meta-analyze correlations, alpha reliabilities, and standardized mean differences. The Synthesizer tool for Microsoft Excel 2007 may be downloaded from the author at www.psychology.iastate.edu/~zkrizan/Synthesizer.htm or as a supplement to the article at http://brm.psychonomic-journals.org/content/supplemental. PMID:20805608

Krizan, Zlatan

2010-08-01

361

Modelling alpha-HCH concentrations in Chinese surface soil  

NASA Astrophysics Data System (ADS)

A gridded mass balance model, Gridded PTSs (persistent toxic substances) Emission and Residue Model (GPERM) on a grid system with a horizontal resolution of 1/6 degree latitude by 1/4 degree longitude, was developed to compile emission and residue inventories for PTSs, including persistent organic pollutants (POPs). The model considers four matrixes, air (air, particulates), soil (air, water and solids), water (water, suspended solids), and sediment (water and solids), and includes 2 components, transfer and transport modules. The transfer module describes the changes of PTS concentrations and inter-compartmental transfer of the substance in the multimedia environment using a level IV fugacity method. The module is solved by a 5th order Runga-Kutta algorithm. The transport module depicts mass exchange of the component between different grid cells due to atmospheric transport, which is solved by a Lagrangian method. The model was used to create Chinese inventories of emission to air and residue in soil from 1952 to 2005 for alpha-hexachlorocyclohexane (alpha-HCH), the major isomer of technical HCH, by integrating interpolated daily meteorological data from the National Centers for Environmental Prediction (NCEP) and interpolated soil density, porosity, organic carbon content, and complied gridded landuse datasets and usage inventories from 1952 to 1984. The results indicate that, concentrations in Chinese surface soil (the soils within HCH manufactures or HCH storage area were not considered here) for 2005 were from < 0.001 pg/g dry weight (dw) to 1,400 pg/g dw with a mean of 94±140 pg/g dw. Modeled soil concentrations agreed well with 162 measured data across China in 2005 by the International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), China (Spearman correlation coefficient R = 0.37, p < 0.05) and 32 measured data for different period and various regions collected from previous literatures (Spearman correlation coefficient R = 0.44, p < 0.05). Both monitoring and model results indicated higher alpha-HCH soil concentrations in the northeastern China than the southeastern China. Historical use of technical HCH was much higher in the southeast of China than the northeast of China during 1952-1984, and the concentrations of alpha-HCH were accordingly higher in the southeast of China than the northeast of China for a long time. The model results showed that, this trend, however, reversed around the beginning of the 2000's, probably indicating the "cold condensation" phenomenon. Detailed discussion will be given during the presentation.

Tian, Chongguo; Liu, Liyan Liu; Jia, Hongliang; Li, Yi-Fan

2010-05-01

362

The Ly-alpha/H-alpha ratio in high-redshift radio galaxies  

NASA Technical Reports Server (NTRS)

The first spectroscopic detection of H-alpha emission from radio galaxies at z greater than 2 are presented. Strong H-alpha emission is detected at z = 2.429 in B3 0731 + 438, and H-alpha is directed at z = 2.428 in 0406 - 244 at a significant level of greater than 6 sigma. The resulting Ly-alpha/H-alpha ratios for 0731 + 438 and 0406 - 244 are 3.9 and 3.2 with 3 sigma uncertainties of 1.5 for each. A range of possible extinctions is derived depending on the reddening-free Ly-alpha/H-alpha ratio assumed and the extinction curve employed. The most important result of this study is the demonstration that the Ly-alpha/H-alpha ratio in distant galaxies can now be measured with relative ease.

Mccarthy, Patrick J.; Elston, Richard; Eisenhardt, Peter

1992-01-01

363

Impact of inhomogeneous optical scattering coefficient distribution on recovery of optical absorption coefficient maps using tomographic photoacoustic data.  

PubMed

We present a study through extensive simulation that considers the impact of inhomogeneous optical scattering coefficient distribution on recovery of optical absorption coefficient maps using tomographic photoacoustic data collected from media mimicking breast tissue. We found that while the impact of scattering heterogeneities/targets is modest on photoacoustic recovery of optical absorption coefficients, the impact of scattering contrast caused by adipose tissue, a layer of normal tissue along the boundary of the breast, is dramatic on reconstruction of optical absorption coefficients using photoacoustic data-up to 25.8% relative error in recovering the absorption coefficient is estimated in such cases. To overcome this problem, we propose a new method to enhance photoacoustic recovery of the optical absorption coefficient in heterogeneous media by considering inhomogeneous scattering coefficient distribution provided by diffuse optical tomography (DOT). Results from extensive simulations show that photoacoustic recovery of absorption coefficient maps can be improved considerably with a priori scattering information from DOT. PMID:23339968

Li, Xiaoqi; Jiang, Huabei

2013-02-21

364

Impact of inhomogeneous optical scattering coefficient distribution on recovery of optical absorption coefficient maps using tomographic photoacoustic data  

NASA Astrophysics Data System (ADS)

We present a study through extensive simulation that considers the impact of inhomogeneous optical scattering coefficient distribution on recovery of optical absorption coefficient maps using tomographic photoacoustic data collected from media mimicking breast tissue. We found that while the impact of scattering heterogeneities/targets is modest on photoacoustic recovery of optical absorption coefficients, the impact of scattering contrast caused by adipose tissue, a layer of normal tissue along the boundary of the breast, is dramatic on reconstruction of optical absorption coefficients using photoacoustic data—up to 25.8% relative error in recovering the absorption coefficient is estimated in such cases. To overcome this problem, we propose a new method to enhance photoacoustic recovery of the optical absorption coefficient in heterogeneous media by considering inhomogeneous scattering coefficient distribution provided by diffuse optical tomography (DOT). Results from extensive simulations show that photoacoustic recovery of absorption coefficient maps can be improved considerably with a priori scattering information from DOT.

Li, Xiaoqi; Jiang, Huabei

2013-02-01

365

Nonlinear Parameter Identification: Lift Coefficient, Drag Coefficient, and Bank Angle Histories for the Space Shuttle Test Flight I.  

National Technical Information Service (NTIS)

A nonlinear, Square-Root Variable-Metric optimization technique is used to extract time histories for the lift coefficient, drag coefficient, and bank angle control variables from radar data of the Space Shuttle Test Flight. This optimization technique so...

H. F. Johnson

1981-01-01

366

DETERMINATION OF OCTANOL/WATER DISTRIBUTION COEFFICIENTS, WATER SOLUBILITIES, AND SEDIMENT/WATER PARTITION COEFFICIENTS FOR HYDROPHOBIC ORGANIC POLLUTANTS  

EPA Science Inventory

Octanol/water distribution coefficients, water solubilities, and sediment/water partition coefficients are basic to any assessment of transport or dispersion of organic pollutants. In addition, these determinations are prerequisites for many chemical or biological process studies...

367

Lymphatic transport of alpha-, gamma- and delta-tocotrienols and alpha-tocopherol in rats.  

PubMed

Lymphatic transport of alpha-, gamma- and delta-tocotrienols and alpha-tocopherol was measured in thoracic duct-cannulated rats. Animals were administered 3 ml of a test emulsion containing 200 mg sodium taurocholate, 50 mg fatty acid free-albumin, 200 mg fat and 100 mg of a mixture of tocotrienols and alpha-tocopherol (Exp. 1) or 10 mg of purified alpha-, gamma- or delta-tocotrienol or alpha-tocopherol (Exp. 2) through a gastric tube. Quantitative lymphatic recovery of oleic acid given as triolein was obtained in these experimental conditions. The 24-hours recovery of tocotrienols and alpha-tocopherol were 10-20% of the administered dose in Exp. 1. The recovery of alpha-tocotrienol was about 2-times higher than that of alpha-tocopherol, while that of gamma- and delta-tocotrienols was intermediate between these two alpha-forms. In Exp. 2, where these compounds were administered individually, the 24 hours recovery ranged from 22 to 37% of the administered dose. Again, the recovery of alpha-tocotrienol was significantly higher than that of the other tocotrienols and alpha-tocopherol, while that of gamma- and delta-tocotrienols and alpha-tocopherol was comparable. Thus, the results show the preferential absorption of alpha-tocotrienol compared to gamma- and delta-tocotrienols and alpha-tocopherol. PMID:8899454

Ikeda, I; Imasato, Y; Sasaki, E; Sugano, M

1996-01-01

368

Nucleic acid encoding MIP-1.alpha. Lymphokine  

US Patent & Trademark Office Database

Full length cDNAs, L2G25B and 4-1BB, were isolated and sequenced. The cDNA L2G25B encodes for the lymphokine, macrophage inflammatory protein-1.alpha. or MIP-1.alpha.. The studies disclosed herein suggest that MIP-1.alpha. and MIP-.beta. can, through rapid action, modulate early myeloid progenitor cell proliferation. Recombinant proteins have been produced for the cytokine, L2G25BP (Macrophage Inflammatory Protein-1.alpha., MIP-1.alpha.). By employing the recombinant protein (rMIP-1.alpha.), receptors for MIP-1.alpha. were identified on Con A-stimulated and unstimulated CTLL-R8, a T-cell line, and LPS-stimulated RAW 264.7, a macrophage-cell line. Purified recombinant murine macrophage inflammatory protein-1 alpha (rmuMIP-.alpha.), was assessed for effects on proliferation of granulocyte-macrophage (CFU-GM), erythroid (BFU-E), and multipotential (CFU-GEMM) progenitor cells. The results suggest that rmuMIP-1.alpha. has myelosuppressive activity in vivo. The cDNA clone, called 4-1BB, is an inducible receptor-like sequence found in both cytolytic and helper T-cells.

2002-03-12

369

Atypical alpha asymmetry in adults with ADHD*  

PubMed Central

Introduction A growing body of literature suggests atypical cerebral asymmetry and interhemispheric interaction in ADHD. A common means of assessing lateralized brain function in clinical populations has been to examine the relative proportion of EEG alpha activity (8– 12 Hz) in each hemisphere (i.e., alpha asymmetry). Increased rightward alpha asymmetry has been associated with ADHD-like traits such as reduced reward responsiveness, a lack of inhibition toward aversive experience, and increased approach behaviors, and previous work has indicated increased rightward alpha asymmetry in children with ADHD. The current study explores whether increased rightward alpha asymmetry is also evident in adults with ADHD. Method We assessed low (8– 10 Hz) and high (10– 12 Hz) alpha asymmetry in adults with ADHD (n = 29) versus controls (n = 62) during baseline and cognitive activation conditions for nine homologous electrode pairs along the anterior–posterior axis. Result Seven results emerged (p < .05) showing increased rightward alpha asymmetry in adults with ADHD. This occurred in three specific electrode pairs across two testing conditions, and five of six results occurred in the lower alpha band. Finally, post hoc analysis indicated that increased rightward alpha asymmetry was generally associated with greater numbers of ADHD symptoms—with a possible parietal association for inattentive and a fronto-temporal association for hyperactivity symptoms. Conclusions Increased rightward alpha asymmetry previously observed in children with ADHD appears to be a developmentally persistent feature of ADHD.

Hale, T. Sigi; Smalley, Susan L.; Hanada, Grant; Macion, James; McCracken, James T.; McGough, James J.; Loo, Sandra K.

2009-01-01

370

The solar Ly-alpha line profile  

NASA Technical Reports Server (NTRS)

Solar Ly-alpha irradiance measurements from the SOLar STellar Irradiance Comparison Experiment (SOLSTICE) on the Upper Atmosphere Research Satellite (UARS) have been made since 1991 October with a spectral resolution of 0.1 nm. The uniqueness of the small molecular oxygen cross section near Ly-alpha permits the Ly-alpha radiation to penetrate much deeper into the atmosphere than the other emissions near Ly-alpha. We have taken advantage of this phenomenon by performing solar occultation experiments near the Ly-alpha to evaluate precisely the instrument scattered light contribution. After correcting for scattered light, the broad wings of the solar Ly-alpha line can be extracted out to 5 nm from line center with a typical accuracy of +/-20%. The variability in the Ly-alpha wings near 2 nm from line center is about one-half that of the Ly-alpha core emission, defined within 0.1 nm from line center. These Ly-alpha profile measurements are found to be consistent with the Skylab radiance measurements and theoretical models of the Ly-alpha line profiles computed using partial redistribution of photons in the source function.

Woods, Thomas N.; Rottman, Gary J.; White, O. R.; Fontenla, Juan; Avrett, E. H.

1995-01-01

371

The intraclass correlation coefficient: distribution-free definition and test.  

PubMed

A definition of the intraclass correlation coefficient is given on the basis of a general class of random effect model. The conventional intraclass correlation coefficient and the intracluster correlation coefficient for binary data are both particular cases of the generalized coefficient. We derive the score test for the hypothesis of null intraclass correlation in the exponential family. The statistic does not depend on the particular distribution in this family and is related to the pairwise correlation coefficient. The test can be adjusted for explanatory variables. PMID:8068852

Commenges, D; Jacqmin, H

1994-06-01

372

High gas flow alpha detector  

DOEpatents

An alpha detector for application in areas of high velocity gas flows, such as smokestacks and air vents. A plurality of spaced apart signal collectors are placed inside an enclosure, which would include smokestacks and air vents, in sufficient numbers to substantially span said enclosure so that gas ions generated within the gas flow are electrostatically captured by the signal collector means. Electrometer means and a voltage source are connected to the signal collectors to generate an electrical field between adjacent signal collectors, and to indicate a current produced through collection of the gas ions by the signal collectors. 4 figs.

Bolton, R.D.; Bounds, J.A.; Rawool-Sullivan, M.W.

1996-05-07

373

New results on P -odd asymmetry of gamma -quanta emission in 10B(n, alpha)7Li* --> gamma + 7Li(g.s.) nuclear reaction  

Microsoft Academic Search

A series of ultra-sensitive experiments has been carried out in 2001-2009 at the ILL measuring P -odd asymmetry in gamma -quanta emission in the nuclear reaction 10B ( n, alpha) 7Li* --> gamma + 7Li(g.s.) with polarized cold neutrons. The resulting value of the asymmetry coefficient is ensuremath alpha_{P{-}odd}= +(0.0 ± 2.6_{stat} ± 1.1_{syst}) × 10^{-8} . These experiments profited

V. A. Vesna; Yu. M. Gledenov; V. V. Nesvizhevsky; P. V. Sedyshev; E. V. Shulgina

2011-01-01

374

Heat transfer coefficient effects on spray cooling  

SciTech Connect

Spray cooling is an integral part of many manufacturing processes and is particularly relevant to high-temperature process. It may be used to simply allow the survival of a unit or to insure that a unit operates at an acceptable temperature. A more recent trend is to use spray cooling to control the final properties of the product. Particular problems are experienced when cooling from the high temperature, stable film boiling regime through Leidenfrost to nucleate boiling. In this case, the published relationships between spray impact density (liters/s/sq meter) and heat transfer coefficient (HTC) are of little use, becoming very inaccurate as cooling proceeds. Mathematical models of cooling are well developed and reliable but need accurate information on the heat removal conditions at the surface of the stock. A test apparatus using a stainless steel specimen cooled from 1,200 C to ambient has been used to investigate the HTC`s from various types of spray, both pressure atomized and air mist, by a transient method. The temperature history is supplied to a mathematical model which works in a reverse iterative manner but with a convergence function. This gives a relationship between HTC and stock temperature over the entire temperature range. Relationships between impact density and HTC are presented for various nozzles and suggestions for further work are made.

Stewart, I.; Massingham, J.D. [British Steel Technical, Moorgate (United Kingdom). Swinden Technology Center; Hagers, J. [Spraying Systems Co., Wheaton, IL (United States)

1995-07-01

375

Testing the Correlated Random Coefficient Model*  

PubMed Central

The recent literature on instrumental variables (IV) features models in which agents sort into treatment status on the basis of gains from treatment as well as on baseline-pretreatment levels. Components of the gains known to the agents and acted on by them may not be known by the observing economist. Such models are called correlated random coe cient models. Sorting on unobserved components of gains complicates the interpretation of what IV estimates. This paper examines testable implications of the hypothesis that agents do not sort into treatment based on gains. In it, we develop new tests to gauge the empirical relevance of the correlated random coe cient model to examine whether the additional complications associated with it are required. We examine the power of the proposed tests. We derive a new representation of the variance of the instrumental variable estimator for the correlated random coefficient model. We apply the methods in this paper to the prototypical empirical problem of estimating the return to schooling and nd evidence of sorting into schooling based on unobserved components of gains.

Heckman, James J.; Schmierer, Daniel; Urzua, Sergio

2010-01-01

376

Attenuation coefficients for water quality trading.  

PubMed

Water quality trading has been proposed as a cost-effective approach for reducing nutrient loads through credit generation from agricultural or point source reductions sold to buyers facing costly options. We present a systematic approach to determine attenuation coefficients and their uncertainty. Using a process-based model, we determine attenuation with safety margins at many watersheds for total nitrogen (TN) and total phosphorus (TP) loads as they transport from point of load reduction to the credit buyer. TN and TP in-stream attenuation generally increases with decreasing mean river flow; smaller rivers in the modeled region of the Ohio River Basin had TN attenuation factors per km, including safety margins, of 0.19-1.6%, medium rivers of 0.14-1.2%, large rivers of 0.13-1.1%, and very large rivers of 0.04-0.42%. Attenuation in ditches transporting nutrients from farms to receiving rivers is 0.4%/km for TN, while for TP attenuation in ditches can be up to 2%/km. A 95 percentile safety margin of 30-40% for TN and 6-10% for TP, applied to the attenuation per km factors, was determined from the in-stream sensitivity of load reductions to watershed model parameters. For perspective, over 50 km a 1% per km factor would result in 50% attenuation = 2:1 trading ratio. PMID:24866482

Keller, Arturo A; Chen, Xiaoli; Fox, Jessica; Fulda, Matt; Dorsey, Rebecca; Seapy, Briana; Glenday, Julia; Bray, Erin

2014-06-17

377

TNF-alpha production in the skin.  

PubMed

Upregulation of TNF-alpha is a key early response to ultraviolet B (UVB) by keratinocytes (KCs), and represents an important component of the inflammatory cascade in skin. UVB irradiation induces TNF-alpha expression in both KCs and dermal fibroblasts, with TNF-alpha mRNA induction seen as early as 1.5 h after UVB. We previously reported that the effects are wavelength-specific: TNF-alpha expression and secretion are induced by UVB (290-320 nm), but not by UVA (320-400 nm). Moreover, we found that IL-1alpha, a cytokine also present in irradiated skin, substantially and synergistically enhances the induction of TNF-alpha by UVB, and the induction of TNF-alpha by this combination of UVB with IL-1alpha is mediated through increased TNF-alpha gene transcription. We investigated the molecular mechanism for UVB-induction of the TNF-alpha gene with a series of TNF-alpha promoter constructs, ranging from 1.2 kbp (from -1179 to +1 with respect to the TNF-alpha transcription initiation site) down to 0.1 kbp (-109 to +1), each driving expression of a CAT reporter. Our results showed a persistent nine to tenfold increase of CAT activity in all TNF-alpha promoter/reporter constructs in response to UVB (30 mJ/cm(2)) exposure. These results indicate the presence of UVB-responsive cis-element(s) located between -109 and +1 of the TNF-alpha promoter, a region that contains a putative AP-1 site and a putative NFkB site. UVB-induction was abolished when the TNF-alpha promoter was mutated by one base pair at the AP-1 binding site. Cells treated with SP600125, an AP-1 inhibitor that inhibits JNK (c-Jun N-terminal kinase), also showed suppression of the 0.1 kbp TNF-alpha promoter/reporter construct. The authentic endogenous gene in untransfected cells was also blocked by the inhibitor. Electrophoretic Mobility Shift Assay indicated new complexes from UVB-treated nuclear extracts and anti-phospho-c-Jun, a regulatory component of the AP-1 transcription factor, creating a supershift indicating increased phosphorylation of c-Jun and hence higher AP-1 activity. Keratinocyte-derived TNF-alpha is a component of the early induction phase of the inflammatory cascade. PMID:18825399

Bashir, M M; Sharma, M R; Werth, V P

2009-01-01

378

Surface diffusion coefficients for room acoustics: free-field measures.  

PubMed

A surface diffusion coefficient is needed in room acoustics to enable the quality of diffusing surfaces to be evaluated. It may also facilitate more accurate geometric room acoustic models. This paper concentrates on diffusion coefficients derived from free-field polar responses. An extensive set of two- and three-dimensional measurements and predictions was used to test the worth of different diffusion coefficient definitions. The merits and problems associated with these types of coefficients are discussed, and past parameters reviewed. Two new coefficients are described. The new measure based on the autocorrelation function is forwarded as the best free-field coefficient. The strengths and weaknesses of the coefficient are defined. PMID:11051498

Hargreaves, T J; Cox, T J; Lam, Y W; D'Antonio, P

2000-10-01

379

IKK{alpha} on Center Stage  

NSDL National Science Digital Library

Inhibitor of κB kinase &alpha; (IKK&alpha;) was originally identified as a component of a multiprotein kinase complex that regulates the activity of the transcription factor nuclear factor-κB (NF-κB) through phosphorylation of its inhibitor proteins, the IκBs. DiDonato discusses new roles that have been discovered for IKK&alpha;, focusing especially on its role in epidermal differentiation and on a new function of IKK&alpha; in B cell maturation. In epidermal differentiation, IKK&alpha; regulates the production of a secreted differentiation factor through a pathway that is independent of its role in activation of NF-κB. In B cell maturation, conventional NF-κB signal-induced activation of IKK&alpha; results in phosphorylation of p100 precursor proteins and increased proteolytic processing and constitutive NF-κB activation.

Joseph A. DiDonato (The Lerner Research Institute at The Cleveland Clinic;Department of Cancer Biology REV)

2001-08-28

380

Ozonation of aqueous solution of alpha endosulfan.  

PubMed

Ozonation of alpha endosulfan and the effects of some parameters such as pH, temperature and partial pressure on ozonation were investigated and the kinetic constants were calculated in this study. Alpha endosulfan solutions were ozonated in a lab-scale semi-batch reactor under variable experimental conditions. Increase in dissolved ozone concentration had a positive effect on oxidation rate. Alpha endosulfan could be removed up to 94% at pH 4 for an ozonation time of 60 minutes. The oxidation reaction was found to be of second order and of first order with respect to both ozone and alpha endosulfan. The temperature dependent reaction expression of alpha endosulfan was obtained as kd = (1.889 exp(- 2.21 x 10(-3)/T). It was concluded that, although the rate of reaction was lower than the rate of other pesticide oxidation reported in the literature. alpha endosulfan presented an obvious reaction to ozonation. PMID:14649713

Yazgan, Mustafa S; Kinaci, Cumali; Toroz, Ismail

2003-11-01

381

Prediction of Protein-protein Interactions Using Alpha Shape Modeling  

NASA Astrophysics Data System (ADS)

Protein-protein interactions play important roles in a lot of biological progress. Previous studies about protein-protein interactions were mainly based on sequence analysis. As more 3D structural information can be obtained from protein-protein complexes, structural analysis becomes feasible and useful. In this study, we used structural alignment to predict the protein-binding site and apply 3D alpha shape modeling to analyze the interface characteristics. We have developed a method for protein-protein interaction prediction. The result indicates good performance of our method in discriminating protein-binding structures from non-protein binding structures. Our method outperforms the previous methods based on the Matthews correlation coefficient.

Zhou, Weiqiang; Yan, Hong; Fan, Xiaodan; Hao, Quan

2011-06-01

382

A model for the disc Lyman alpha emission of Uranus  

NASA Technical Reports Server (NTRS)

A new efficient radiative transfer algorithm for nonhomogeneous model atmospheres has been applied to the Uranian atmosphere. The contribution of the scatter solar Lyman-alpha to the Uranain emission is of the order of 300 R, and the Rayleigh contribution may reach 450 R for small values of the eddy diffusion coefficient (EDC). The total solar contribution may then reach about 750 R for a solar flux of 2.5 x 10 to the 11th photons/sq cm/s/A. A level of up to 400 R is confirmed in some directions for the interstellar wind contribution. The values of the atmospheric EDC necessary to mimic the observations are 50-100 sq cm/s. A small additional source located on the dayside Uranian atmosphere seems necessary correctly to fit the shape of the limb to limb intensity variation, especially near the limbs. Its contribution to the emergent intensity would range from 100 to 500 R.

Ben Jaffel, L.; Prange, R.; Emerich, C.; Vidal-Madjar, A.; Mcconnell, J. C.

1991-01-01

383

Mathematical model of an air-filled alpha stirling refrigerator  

NASA Astrophysics Data System (ADS)

This work develops a mathematical model for an alpha Stirling refrigerator with air as the working fluid and will be useful in optimizing the mechanical design of these machines. Two pistons cyclically compress and expand air while moving sinusoidally in separate chambers connected by a regenerator, thus creating a temperature difference across the system. A complete non-linear mathematical model of the machine, including air thermodynamics, and heat transfer from the walls, as well as heat transfer and fluid resistance in the regenerator, is developed. Non-dimensional groups are derived, and the mathematical model is numerically solved. The heat transfer and work are found for both chambers, and the coefficient of performance of each chamber is calculated. Important design parameters are varied and their effect on refrigerator performance determined. This sensitivity analysis, which shows what the significant parameters are, is a useful tool for the design of practical Stirling refrigeration systems.

McFarlane, Patrick; Semperlotti, Fabio; Sen, Mihir

2013-10-01

384

Beta/alpha continuous air monitor  

DOEpatents

A single deep layer silicon detector in combination with a microcomputer, recording both alpha and beta activity and the energy of each pulse, distinquishing energy peaks using a novel curve fitting technique to reduce the natural alpha counts in the energy region where plutonium and other transuranic alpha emitters are present, and using a novel algorithm to strip out radon daughter contribution to actual beta counts. 7 figs.

Becker, G.K.; Martz, D.E.

1988-06-27

385

On alpha heating in toroidal devices  

Microsoft Academic Search

Studies of the alpha particle losses and heating profiles for an alpha-heated TFTR-sized tokamak and a small field-reversed mirror reactor (FRM) are presented. The slowing-down and drift of high-energy alpha particles, including detailed orbital effects, is approximated for tokamak geometry using the SYMALF multi-energy-angle code. Results of the calculation for a beam-driven TFTR-type plasma indicate that, except for the center

G. H. Miley

1979-01-01

386

Improvements to alpha-particle spectrometry techniques.  

PubMed

Improvements to the conventional methods for alpha-particle spectrometry measurement and analysis have recently been implemented in our laboratory. They include the application of corrections for energy drift in long-duration measurements, the development and application of an efficient deconvolution method for complex alpha spectra using the new computer code ALFITeX, an alpha-gamma coincidence system using a dual-parameter multichannel analyzer, and the digitization of this coincidence system. PMID:24315085

Caro Marroyo, B; Martín Sánchez, A; Jurado Vargas, M

2014-05-01

387

Catalytic poly alpha-olefin process  

Microsoft Academic Search

A process is described for oligomerizing an alpha-olefin which comprises contacting a transition metal halide and an organic halide with an alpha-olefin and thereafter an alkyl aluminum compound in a reaction zone. The mole ratio of the active halogen to aluminum is from 2.5 to 25. The alpha-olefin is oligomerized to form oligomers having a molecular weight of from about

Loveless

1987-01-01

388

Beta/alpha continuous air monitor  

DOEpatents

A single deep layer silicon detector in combination with a microcomputer, recording both alpha and beta activity and the energy of each pulse, distinguishing energy peaks using a novel curve fitting technique to reduce the natural alpha counts in the energy region where plutonium and other transuranic alpha emitters are present, and using a novel algorithm to strip out radon daughter contribution to actual beta counts.

Becker, Gregory K. (Idaho Falls, ID); Martz, Dowell E. (Grand Junction, CO)

1989-01-01

389

Alpha,2-, alpha,3-, and alpha,4-dehydrophenol radical anions: formation, reactivity, and energetics leading to the heats of formation of alpha,2-, alpha,3-, and alpha,4-oxocyclohexadienylidene.  

PubMed

We have regiospecifically generated the alpha,2-, alpha,3-, and alpha,4-dehydrophenoxide anions by collisional activation of o-, m-, and p-nitrobenzoate. The alpha,2 and alpha,4 isomers also were synthesized by reacting o-benzyne radical anion with carbon dioxide and electron ionization of p-diazophenol. All three dehydrophenol radical anions were differentiated from each other and identified by probing their chemical reactivity with several reagents. Each isomer was converted to phenoxide and its corresponding quinone as well. Thermochemical measurements were carried out on all three radical anions and their hydrogen-atom affinities, proton affinities, and electron binding energies are reported. These measured quantities are combined in thermodynamic cycles to derive the heats of formation of each of the radical anions and their corresponding carbenes (i.e., alpha,2-, alpha,3-, and alpha,4-dehydrophenol). These results are compared to MCQDPT2, G3, G2+(MP2), and B3LYP calculations and experimental data for appropriate reference compounds. PMID:12683837

Reed, Dana R; Hare, Michael C; Fattahi, Alireza; Chung, Gyusung; Gordon, Mark S; Kass, Steven R

2003-04-16

390

Normative references of heart rate variability and salivary alpha-amylase in a healthy young male population  

PubMed Central

Background This study aimed to present normative reference values of heart rate variability and salivary alpha-amylase in a healthy young male population with a particular focus on their distribution and reproducibility. Methods The short-term heart rate variability of 417 young healthy Japanese men was studied. Furthermore, salivary alpha-amylase was measured in 430 men. The average age of the subjects were 21.9 years with standard deviation of 1.6 years. Interindividual variations in heart rate variability indices and salivary alpha-amylase levels were plotted as histograms. Data are presented as the mean, median, standard deviation, coefficient of variation, skewness, kurtosis, and fifth and 95th percentiles of each physiological index. Results Mean recorded values were heart period 945.85 ms, log-transformed high frequency component 9.84 ln-ms2, log-transformed low frequency component 10.42 ln-ms2, log-transformed low frequency to high frequency ratio 0.58 ln-ratio, standard deviation of beat-to-beat interval 27.17 ms and root mean square of successive difference 37.49 ms. The mean value of raw salivary alpha-amylase was 17.48 U/mL, square root salivary alpha-amylase 3.96 sqrt[U/mL] and log-transformed salivary alpha-amylase 2.65 ln[U/mL]. Log-transformed heart rate variability indices exhibited almost symmetrical distributions; however, time-domain indices of heart rate variability (standard deviation of beat-to-beat interval and root mean square of successive difference) exhibited right-skewed (positive skewness) distributions. A considerable right-skewed distribution was observed for raw salivary alpha-amylase. Logarithmic transformation improved the distribution of salivary alpha-amylase, although square root transformation was insufficient. The day-to-day reproducibility of these indices was assessed using intraclass correlation coefficients. Intraclass correlation coefficients of most heart rate variability and salivary indices were approximately 0.5 to 0.6. Intraclass correlation coefficients of raw salivary markers were approximately 0.6, which was similar to those of heart rate variability; however, log transformation of the salivary markers did not considerably improve their reproducibility. Correlations between sympathetic indicators of heart rate variability and salivary alpha-amylase were not observed. Conclusion Because the sample population examined in this study involved limited age and gender variations, the present results were independent of these factors and were indicative of pure interindividual variation.

2012-01-01

391

The Problem Areas in Diabetes (PAID) scale: psychometric evaluation survey in a Greek sample with type 2 diabetes.  

PubMed

Several instruments have been developed for the assessment of emotional distress in patients with diabetes. The Problem Areas in Diabetes Scale (PAID) is a brief self-report scale that evaluates diabetes-related distress. There is a lack of validated instruments for the evaluation of psychological aspects in patients with diabetes in Greek language. The current study was conducted to translate and adapt the PAID scale in Greek language and to evaluate the psychometric properties in two different study populations of patients with diabetes. The aim of this study was to translate the Problem Areas in Diabetes (PAID) scale into Greek, adapt it culturally to Greece and determine its psychometric properties. The translation process included two forward translations, reconciliation, backward translation and pre-testing steps. The validation incorporated the exploration of internal consistency (Cronbach's alpha), test-retest reliability (interclass correlation coefficient), construct validity (exploratory factor analysis) and responsiveness (Spearman correlation coefficient). Participants included 101 consecutive patients from a rural primary healthcare centre and 101 patients from an urban hospital. All patients completed the PAID scale and the Short Form-36 (SF-36) version 2. Internal consistency considered good (Cronbach's alpha = 0.948). Interclass correlation coefficient was 0.942 (95% CI 0.915-0.961). Factor analysis yielded three factors: 'Diabetes-related emotional problems' (51.79% variance, Cronbach's alpha = 0.910), 'Food-related problems' (9.55% variance, Cronbach's alpha = 0.824) and 'Social support-related problems' (5.96% variance, Cronbach's alpha = 0.704). Screen plot test and conceptual congruency of items supported a three-factor solution. Total PAID showed a negative correlation with both SF-36 mental component summary (r = -0.733, P < 0.0001) and SF-36 physical component summary (r = -0.594, P < 0.0001). Our findings indicate that the Greek version of the PAID questionnaire is reliable and valid for patients with diabetes mellitus in Greece. PMID:22340071

Papathanasiou, A; Koutsovasilis, A; Shea, S; Philalithis, A; Papavasiliou, S; Melidonis, A; Lionis, C

2014-05-01

392

Alpha-physics and measurement requirements for ITER  

SciTech Connect

This paper reviews alpha particle physics issues in ITER and their implications for alpha particle measurements. A comparison is made between alpha heating in ITER and NBI and ICRH heating systems in present tokamaks, and alpha particle issues in ITER are discussed in three physics areas: `single particle` alpha effects, `collective` alpha effects, and RF interactions with alpha particles. 29 refs., 4 figs., 4 tabs.

Zweben, S.J.; Young, K.M. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Putvinski, S. [ITER Joint Central Team, La Jolla, CA (United States); Petrov, M.P. [Ioffe Physical-Technical Inst., St. Petersburg, RU (Russian Federation); Sadler, G. [JET Joint Undertaking, Abingdon, Oxfordshire (United Kingdom); Tobita, K. [JAERI, Naka-machi, Naka-gun, Ibaraki (Japan)

1995-12-31

393

Distribution Coefficients of Impurities in Metals  

NASA Astrophysics Data System (ADS)

Impurities dissolved in very pure metals at the level of parts per million often cause an elevation or depression of the freezing temperature of the order of millikelvins. This represents a significant contribution to the uncertainty of standard platinum resistance thermometer calibrations. An important parameter for characterizing the behavior of impurities is the distribution coefficient k , which is the ratio of the solid solubility to liquid solubility. A knowledge of k for a given binary system is essential for contemporary methods of evaluating or correcting for the effect of impurities, and it is therefore of universal interest to have the most complete set of values possible. A survey of equilibrium values of k (in the low concentration limit) reported in the literature for the International Temperature Scale of 1990 fixed points of Hg, Ga, In, Sn, Zn, Al, Au, Ag, and Cu is presented. In addition, thermodynamic calculations of k using MTDATA are presented for {>} 170 binary systems. In total, the combined values of k from all available sources for {>} 430 binary systems are presented. In addition, by considering all available values of k for impurities in 25 different metal solvents ({>} 1300 binary systems) enough data are available to characterize patterns in the value of k for a given impurity as a function of its position in the periodic table. This enables prediction of k for a significant number of binary systems for which data and calculations are unavailable. By combining data from many sources, values of k for solutes (atomic number from 1 to 94) in ITS-90 fixed points from Hg to Cu are suggested, together with some tentative predicted values where literature data and calculations are unavailable.

Pearce, J. V.

2014-04-01

394

[Simulation of backscattering coefficients of inland waters].  

PubMed

When we simulated backscattering coefficients (b(bp)) using quasi-analytical algorithm and optical closure theory, it was found that the position of reference wavelength (lambda(0)) had great impact on final results. In order to identify influence factors of the optimum lambda(0), datasets of Lake Taihu, Lake Chaohu and Lake Dianchi were used. After simulating of b(bp), the relationship between optimum lambda(0) and associated water quality parameters were analyzed. Meanwhile, power functions were utilized to model b(bp) spectra, and spectral slope parameters of Lake Taihu, Lake Chaohu and Lake Dianchi were 2.643 +/- 0.317, 2.719 +/- 0.242, 1.638 +/- 0.534, respectively. The results indicate that: (1) When the whole lakes are taken as objects of study, the lambda(0) should be changed to longer wavelength with the increasing of total suspended particle matter concentration (c(SPM)), suspended organic particle matter concentration (c(SPOM)) and chlorophyll a concentration (c(CHL)), the optimum location of lambda(0) of Lake Taihu is 695 nm, Lake Chaohu is 720 nm and Lake Dianchi is 730 nm; (2) When the samples in lakes are taken as objects of study, the influence factors are different due to the complexity of optical properties of inland waters. But it is to be noted that, c(SPM) is a key factor in common. Besides, the regularity mentioned above should be weakened with high c(CHL). (3) The relationship between b(bp) and c(SPM) is much stronger in the waters with suspended particles dominated by inorganic particles, in Lake Taihu, for example, relationship between these two variables is strong with R2 = 0.852. PMID:22165215

Zhang, Hong; Li, Yun-Mei; Huang, Jia-Zhu; Liu, Zhong-Hua; Xu, Yi-Fan; Xu, Xin; Guo, Yu-Long; Tan, Jing

2011-09-01

395

A simple application of the Bailey-Orowan creep model to Fe-39.8 at. pct Al and gamma/gamma prime - alpha  

NASA Technical Reports Server (NTRS)

The results of a study to determine the recovery rates and work-hardening coefficients for creep from constant cross-head speed compressive tests are presented. Stressing and straining rates are computed from measured time-load curves obtained from compression testing between 1200 and 1400 K of several B2 crystal structure Fe-39.8 Al intermetallic materials and the directionally solidified eutectic alloy gamma/gamma prime alpha. These quantities are then fitted to the universal form of the Bailey-Orowan equation for creep. The recovery rates were found to be functions of nominal strain rate, stress, and temperature, while the hardening coefficients were dependent only on temperature. While the work-hardening coefficient for gamma/gamma prime - alpha was about 0.05 of the elastic modulus, the work-hardening coefficients for Fe-39.8 at. pct Al were less than 0.002 of the modulus.

Whittenberger, J. D.; Krishnan, R. V.

1984-01-01

396

Collagen IV alpha 3, alpha 4, and alpha 5 chains in rodent basal laminae: sequence, distribution, association with laminins, and developmental switches  

PubMed Central

Collagen IV is a major component of vertebrate basal laminae (BLs). Studies in humans have revealed a family of genes encoding alpha 1- alpha 6 collagen IV chains and implicated alpha 3-alpha 6 in disease processes (Goodpasture and Alport syndromes and diffuse leiomyomatosis). To extend studies of these components to an experimentally accessible animal, we cloned cDNAs encoding partial collagen alpha 3, alpha 4, and alpha 5(IV) chains from the mouse. Ribonuclease protection assays showed that all three genes were expressed at highest levels in kidney and lung; alpha 5(IV) was also expressed at high levels in heart. We then made antibodies specific for each collagen IV chain. Immunohistochemical studies of several tissues revealed many combinations of collagen IV chains; however, alpha 3 and alpha 4 (IV) were always coexpressed, and only appeared in BLs that were alpha 5(IV) positive. The alpha 3-alpha 5(IV) chains were frequently but not exclusively associated with the S (beta 2) chain of laminin, as were the alpha 1, 2 (IV) collagen chains with laminin B1 (beta 1). An analysis of developing rat kidney BLs showed that newly formed (S-shaped) nephrons harbored collagen alpha 1 and alpha 2(IV) and laminin B1; maturing (capillary loop stage) BLs contained collagen alpha 1-alpha 5(IV) and laminin B1 and S-laminin; and mature glomerular BLs contained mainly collagen alpha 3-alpha 5(IV) and S-laminin. Thus, collagen alpha 1 and alpha 2(IV) and laminin B1 appear to be fetal components of the glomerular BL, and there is a developmental switch to collagen alpha 3-alpha 5(IV) and S-laminin expression.

1994-01-01

397

Application of the Oral Health Impact Profile (OHIP) among Taiwanese elderly  

Microsoft Academic Search

Purpose  To validate the Chinese (Taiwan) version of the Oral Health Impact Profile (OHIP-49T) and develop a short form of the OHIP\\u000a (OHIP-14T) for the elderly.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  A total of 1402 subjects, aged 65 and above, received a personal interview and oral examination. Internal consistency, measured\\u000a by Cronbach’s alpha, and test–retest reliability were assessed by intra-class correlation coefficient (ICC) during a 2-week

Hsiao-Ching Kuo; Jen-Hao Chen; Ju-Hui Wu; Tsau-Mau Chou; Yi-Hsin Yang

398

Impedance computed tomography using an adaptive smoothing coefficient algorithm.  

PubMed

In impedance computed tomography, a fixed coefficient regularization algorithm has been frequently used to improve the ill-conditioning problem of the Newton-Raphson algorithm. However, a lot of experimental data and a long period of computation time are needed to determine a good smoothing coefficient because a good smoothing coefficient has to be manually chosen from a number of coefficients and is a constant for each iteration calculation. Thus, sometimes the fixed coefficient regularization algorithm distorts the information or fails to obtain any effect. In this paper, a new adaptive smoothing coefficient algorithm is proposed. This algorithm automatically calculates the smoothing coefficient from the eigenvalue of the ill-conditioned matrix. Therefore, the effective images can be obtained within a short computation time. Also the smoothing coefficient is automatically adjusted by the information related to the real resistivity distribution and the data collection method. In our impedance system, we have reconstructed the resistivity distributions of two phantoms using this algorithm. As a result, this algorithm only needs one-fifth the computation time compared to the fixed coefficient regularization algorithm. When compared to the fixed coefficient regularization algorithm, it shows that the image is obtained more rapidly and applicable in real-time monitoring of the blood vessel. PMID:11575468

Suzuki, A; Uchiyama, A

2001-01-01

399

Selective solid-phase extraction of alpha-tocopherol by functionalized ionic liquid-modified mesoporous SBA-15 adsorbent.  

PubMed

Ordered mesoporous adsorbents were prepared by physically grafting functionalized ionic liquids onto SBA-15 (a mesoporous siliceous substrate) using incipient wetness immersion method. These adsorbents were successfully applied to the selective extraction and separation of alpha-tocopherol (an isomer of vitamin E) from a model mixture of soybean oil deodorizer distillate. Various parameters affecting adsorption process such as adsorption time, the structures and loadings of ionic liquids, the adsorption isotherm, and the reusability of adsorbent were investigated using liquid-solid extraction. As high as 211 mg/g adsorbent of the adsorption capacity for alpha-tocopherol was obtained through the adsorption isotherm tests using [emim][Gly]/SBA-15 (functionalized ionic liquid 1-ethyl-3-methylimidazolium glycine which was physically coated on SBA-15) as the adsorbent, in which the functionalized ionic liquids contained the amino acid glycine as the anion. The adsorbent [emim][Gly]/SBA-15 also exhibited a very high adsorption selectivity for alpha-tocopherol. The extraction selectivity or the ratio of distribution coefficients between alpha-tocopherol and the major interference component glyceryl triundecanoate (K(d(alpha-tocopherol))/K(d(triglyceride))) was 10.5. The concentration of alpha-tocopherol was significantly increased from 15.6% in original feedstock solution that contained fatty acid methyl ester, triglyceride and alpha-tocopherol to 73.0% after stripping by diethyl ether. Five adsorbent recycle tests showed good reusability of the functionalized ionic liquid-modified mesoporous adsorbent. PMID:18845881

Li, Min; Pham, Patrisha J; Pittman, Charles U; Li, Tingyu

2008-10-01

400

The Application for Express Evaluation of Alpha Parameter in Plutonium Materials.  

SciTech Connect

When processing the results of neutron measurements it is useful in some cases to be able to assess the value of the alpha parameter (ratio of neutron production rate due to (alpha, n) reaction to that due to spontaneous fission) in a sample. The application was developed for the express evaluation of the parameter for plutonium-bearing materials based on the isotopic composition of plutonium and the elemental content of compound. The application exploits a traditional approach using Ziegler’s coefficients to calculate alpha particle stopping powers. However, the application uses weight values instead of atomic ones as input data of elemental content that in turn allows easily evaluate the parameter for any material (both pure “theoretical” compound and real one containing various impurities). A practical advantage is that a user needs to know weight content of elements (as a normal practice) and not chemical formulae for all components of a compound. Some results of comparison between the Alpha Parameter application and the well known code Sources4A are presented. The application was verified and validated by PNNL for its usage in NDA project. Alpha parameter is freeware and available on request from authors.

Mozhayev, Andrey V.; Bulanenko, Valery I.

2004-11-01

401

Copernicus Measurement of the Jovian Lyman-alpha emission and its aeronomical significance  

SciTech Connect

Observations of Jupiter made with the high-resolution ultraviolet spectrometer of the Orbiting Astronomical Observatory Copernicus in 1980 April and May yield the intensity of the Jovian Lyman-alpha emission to be 7 +- 2.5 kR. These measurements indicate that the Lyman-alpha intensity has decreased by about a factor of 2 from the time of the Voyager ultraviolet spectrometer measurements, nearly a year earlier. The Copernicus measurements, when combined with all other previous measurements of the Jovian Lyman-alpha emission, point to an unusually high column abundance of hydrogen atoms above the methane homopause at the Voyager epoch. Since the auroral charged particle bombardment of moelcular hydrogen is expected to contribute significantly to the global population of the hydrogen atoms, it is suggested that at the time of the Voyager Jupiter encounter, unusually high auroral activity existed, and it was perhaps linked to the high concentration of the Io plasma torus. It should be pointed out that the temporal variation of the Saturn Lyman-alpha emission, when contrasted with the Jovian data, reveals that the auroral processes are not nearly as important in determining the Saturn Lyman-alpha intensity in the nonauroral region. The latest Copernicus observations also suggest an increase in the Jovian homopause value of the eddy mixing coefficient by about a factor of 5--10 since the Voyager epoch.

Atreya, S.K.; Festou, M.C.; Donahue, T.M.; Kerr, R.B.; Barker, E.S.; Cochran, W.D.; Bertaux, J.L.; Upson, W.L. II

1982-11-01

402

Switching from Epoetin Alpha to Darbepoetin Alpha in Japanese Hemodialysis Patients: Dose Conversion Ratio  

Microsoft Academic Search

Background\\/Aims: Darbepoetin alpha is an erythropoietic agent with a 3-fold longer elimination half-life than epoetin. The recommended conversion ratio from epoetin to darbepoetin alpha is 1:200 (1 ?g of darbepoetin alpha = 200 IU of epoetin), but several observations have suggested that this ratio overestimates the required dose of darbepoetin alpha. This study assessed the actual conversion ratio for stable

Takayuki Hirai; Naoko Sugiya; Ayumu Nakashima; Norihisa Takasugi; Noriaki Yorioka

2009-01-01

403

/sup 20/Ne(. cap alpha. ,2. cap alpha. )/sup 16/O reaction  

SciTech Connect

The /sup 20/Ne(..cap alpha..,2..cap alpha..)/sup 16/O reaction at 140 MeV incident energy is analyzed in the framework of the distorted-wave impulse approximation. The bound state ..cap alpha.. wave functions in /sup 20/Ne are generated using the orthogonal condition model. The predicted results agree with the experimental data. They are also in rough accord with the results obtained with the Woods-Saxon ..cap alpha.. wave function.

Sharma, N.R.; Jain, B.K.; Shyam, R.

1988-02-01

404

A microprecipitation technique suitable for measuring alpha-lipoprotein cholesterol.  

PubMed

A semi-automated method has been developed for determining alpha-lipoprotein cholesterol values. Precipitation of apolipoprotein B containing lipoproteins takes place in wells of microtiter plates after 100 microL of serum are mixed with 20 microL of a heparin/MnCl2 solution. A Beckman (Fullerton, CA) Biomek 1000 work station is used to transfer sera, supernatants and reagents between tubes and microtiter plates. Supernatant cholesterol is determined enzymatically, and absorbances are read at 490 nm using a Molecular Devices Corporation (Palo Alto, CA) plate reader. Values obtained on both fresh and frozen serum samples agreed with corresponding data obtained at the Centers for Disease Control (CDC; Atlanta, GA). For the fresh samples, the average bias was 2.87%. The within-run coefficients of variations were between 2.2 and 0.6% for the data obtained on CDC frozen control pools. The results indicate that the semi-automated method is suitable for obtaining accurate and precise data for alpha-lipoprotein cholesterol. The method lends itself to the analysis of large numbers of samples and is particularly suited for the study of lipoproteins of small mammals. PMID:7990668

Puppione, D L; Charugundla, S

1994-08-01

405

Carbohydrate composition of the alpha-subunit of human choriogonadotropin (hCG alpha) and the free alpha molecules produced in pregnancy: most free alpha and some combined hCG alpha molecules are fucosylated.  

PubMed

The carbohydrate compositions of pregnancy-derived hCG alpha (dissociated from intact hCG) and free alpha-subunit were analyzed using a combination of chemical analysis, lectin affinity chromatography, and glycosidase sensitivity. For direct compositional analysis, parallel samples were hydrolyzed in trifluoroacetic acid and analyzed for sialic acid and neutral sugars without prior derivatization. Separation of the monosaccharides was achieved by HPLC on a Dionex CarboPac column eluted at high pH, and the resolved monosaccharides were quantified by pulsed amperometric detection. The amounts of sugar that were found relative to peptide indicated the presence of two N-linked oligosaccharides per molecule on both hCG alpha and free alpha. Free alpha contained 2.5-fold higher amounts of sialic acid and galactose as well as a higher amount of N-acetylglucosamine than did hCG alpha. Free alpha also contained a 6-fold higher amount of fucose than did hCG alpha (1.2 vs. 0.2 residues of fucose/molecule). Serial fractionation of intact hCG alpha and free alpha molecules by lectin affinity chromatography indicated that virtually all of the hCG alpha-subunits contained at least one Concanavalin-A (Con-A)-binding site, whereas as many as 32% of the free alpha molecules could not bind to Con-A. Chromatography on Lens culinaris (Lch) resulted in 12% binding of hCG alpha and approximately 72% binding of free alpha (80-85% of the Con-A-bound free alpha and 47-48% of the Con-A-nonbound free alpha bound to Lch). Endoglycosidase-H (endo-H) treatment of hCG alpha released a portion of the oligosaccharides. The endo-H-released material appeared to be a monoantennary hybrid based on DEAE-binding properties and carbohydrate composition. In contrast to hCG alpha, free alpha was completely resistant to endo-H treatment. Incubation of endo-H-resistant hCG alpha with glycopeptidase-A resulted in the release of two components, which could be separated into monoantennary and biantennary fractions on the basis of size and charge. The collective data suggest that hCG alpha contains primarily monoantennary hybrid oligosaccharide structures and relatively little fucose. In contrast, free alpha contains primarily multiantennary oligosaccharide structures, and most of the free alpha molecules contain at least one oligosaccharide with fucose attached to the asparagine-linked N-acetylglucosamine residue. PMID:1693562

Blithe, D L

1990-06-01

406

Measured and predicted shock shapes and aerodynamic coefficients for blunted cones at incidence in helium at Mach 20.3  

NASA Technical Reports Server (NTRS)

Experimental values of shock shapes (alpha = 0 degrees and 10 degrees) and static aerodynamic coefficients (alpha = -4 degrees to 12 degrees) for sharp and spherically blunted cones having cone half-angles of 30, 45, 60, and 70 degrees and nose bluntness ratios of 0, 0.25, and 0.50 are presented. Shock shapes were also measured at 0 degree angle of attack by using a flat-faced cylinder (90 degree cone) and a hemispherically blunted cylinder (sphere). All tests were conducted in helium (gamma = 5/3) at a free-stream Mach number of 20.3 and a unit free-stream Reynolds number of 22,400,000 per meter. Comparisons between measured values and predicted values were made by using several numerical and simple engineering methods.

Calloway, R. L.; White, N. H.

1979-01-01

407

Optical Model Parameters for the Ar-36+{alpha} and Ca-40+{alpha} Systems  

SciTech Connect

For 36Ar+{alpha} and 40Ca+{alpha} systems there are presented the parameters of Woods-Saxon potential with volume absorption in the {alpha}-particle energy range lower and higher than the Coulomb barrier. They were obtained as a result of existing optical potentials modification.

Generalov, L.; Zvenigorodskii, A. [Russian Federal Nuclear Center-VNIIEF, Sarov (Russian Federation)

2005-05-24

408

An exact shell-model treatment of alpha-clustering and absolute alpha-decay  

Microsoft Academic Search

The alpha clustering and corresponding alpha decay of 212Po is studied within the framework of a multistep shell-model method. All interactions among the four nucleons that constitute the alpha particle are included and a large single-particle representation is used. It is found that this approach is not sufficient to explain the available experimental data.

G. Dodig-Crnkovic; F. A. Janouch; R. J. Liotta

1989-01-01

409

Generalized theory of varying alpha  

NASA Astrophysics Data System (ADS)

In this paper, we formulate a generalization of the simple Bekenstein-Sandvik-Barrow-Magueijo theory of varying alpha by allowing the coupling constant ? for the corresponding scalar field ? to depend on ?. We focus on the situation where ? is exponential in ? and find the late-time behaviors that occur in matter-dominated and dark-energy dominated cosmologies. We also consider the situation when the background expansion scale factor of the Universe evolves in proportion to an arbitrary power of the cosmic time. We find the conditions under which the fine-structure “constant” increases with time, as in the Bekenstein-Sandvik-Barrow-Magueijo theory, and establish a cosmic no-hair behavior for accelerating universes. We also find the conditions under which the fine-structure constant can decrease with time and compare the whole family of models with astronomical data from quasar absorption spectra.

Barrow, John D.; Lip, Sean Z. W.

2012-01-01

410

Alpha-fetoprotein in Abortion  

PubMed Central

The clinical value of maternal serum alpha-fetoprotein (AFP) as a guide to the outcome of threatened abortion was assessed. After the thirteenth week of gestation, abortion occurred more frequently (10/12) in women with abnormal serum AFP levels than in those (2/12) whose AFP concentrations were within the normal range. Low levels were present in women with blighted ovum and high concentrations were associated with intrauterine fetal death. In legal first and second trimester abortions, the circulating maternal AFP levels in postabortion samples were often higher than before abortion, irrespective of whether abortion was performed instrumentally or induced with prostaglandins. Maternal serum AFP levels provide a new means for prediction of the outcome of threatened abortion. ImagesFIG. 1FIG. 2

Seppala, Markku; Ruoslahti, Erkki

1972-01-01

411

[Influence of petroleum concentration in water on spectral backscattering coefficient].  

PubMed

The petroleum pollutants mixing proportion experiment and in-situ experiment were carried out in the estuary of Panjin, Liaoning province in May 2008 and August 2009. The optical properties and biochemical properties were measured to get the effect of petroleum concentration in water on backscattering coefficients spectrum. The results show that the power-law index of backscattering coefficient decreases as TSM concentration increases and the relationship of these variables follows logarithm mode. Specific backscattering coefficient's value of 440 to 856 nm is between 0.006 and 0.035 m2 x g(-1) and decreases as wavelength increases. The petroleum mass-specific backscattering coefficients (backscattering coefficients of unit petroleum concentration) decreases with the wavelength increasing and follows power law for petroleum concentration. Petroleum concentration has little effect on the power-law index of backscattering coefficient. PMID:21105413

Song, Qing-jun; Huang, Miao-fen; Tang, Jun-wu; Wang, Xiao-mei

2010-09-01

412

Application of sensitivity coefficients for heat conduction problems  

SciTech Connect

In parameter estimation considerable insight is provided by examining sensitivity coefficients. This paper focuses on the use of sensitivity coefficients in connection with estimating thermal properties in the heat conduction equation. A general methodology for computing sensitivity coefficients can be an important design tool. The use of such a tool is demonstrated in this paper. A control volume, finite element program is used, and briefly described, to implement numerical sensitivity coefficient calculations. In this approach general problems can be studied. Several example problems are presented to demonstrate the insight gained from sensitivity coefficients. The problems are selected from experimental studies to characterize the thermal properties of carbon-carbon composite. Sensitivity coefficients show that in an experiment that is not well designed, additional materials in the experimental configuration can have a larger impact on the temperature than the material of interest. Two-dimensional configurations demonstrate that there can be isolated areas of insensitivity and the difficulty of estimating multiple parameters.

Dowding, K.J.; Blackwell, B.F.; Cochran, R.J.

1998-02-01

413

High-alpha space trucks  

SciTech Connect

Vertically-landing Reusable Launch Vehicles (RLVs) are the best hope of building a true {open_quotes}Space Truck{close_quotes} with current technology. Because they do not require a low angle-of-attack (AOA, or alpha) horizontal landing, they can be designed to operate exclusively at very high angles-of-attack. This offers savings in vehicle dry weight and complexity, which can be traded for significantly heavier payload, more ascent velocity, or extra design margin. The price for abandoning low angle-of-attack flight is reduced crossrange. To quantify the potential weight reduction, a trade study was performed to determine the relationship between a vehicle{close_quote}s maximum crossrange (angle-of-attack) and it{close_quote}s dry weight (payload margin). At the study conclusion, three vertically-landing (VL) vehicles provided multiple points on a payload weight vs. maximum crossrange curve, showing significant payload increases as crossrange is sacrificed. This is primarily the result of being able to simplify the structure, fly a cooler entry trajectory, and be aerodynamically stable through the entire flight. This reduces subsystem requirements and complexity, enhancing reliability. Further benefits are realized in reduced landing propellant requirements and simplifying or eliminating the {open_quotes}rotation{close_quotes} maneuver. This paper also suggests unique operability solutions that adapt high-alpha vehicles to traditional high-crossrange missions such as the polar {open_quotes}once-around{close_quotes} flight, and proposes a small scale drop-test program to prove the subsonic and landing portion of the flight envelope. {copyright} {ital 1997 American Institute of Physics.}

Cook, L.M. [Ball Aerospace and Technology Corp. 1600 Commerce St. MS CO-9 Boulder, Colorado80301 (United States); Ball, J. [McDonnel Douglas Aerospace 5301 Bolsa Ave. MS 13-3 Huntington Beach, California92647 (United States)

1997-01-01

414

Evaluation of distribution coefficients in micellar liquid chromatography  

Microsoft Academic Search

The possibilities of micellar liquid chromatography for evaluating distribution coefficients are discussed. Determination of solute-micelle association constants and distribution coefficients of solutes between stationary-aqueous, stationary-micellar and aqueous-micellar phases is described. Application of the calculation of distribution coefficients to the study of the retention mechanism of solutes in the chromatographic system and prediction of separation selectivity is also presented.

M. L. Marina; M. A. García

1997-01-01

415

Tunable Seebeck Coefficient in Monolayer Graphene Under Periodic Potentials  

NASA Astrophysics Data System (ADS)

The effect of the superlattice potential on the Seebeck coefficient tensor of graphene sheet is theoretically investigated. Strong anisotropy of the Seebeck coefficient tensor is observed. The origin of the anisotropy can be attributed to the modification of the dispersion relation in the vicinity of the Dirac point. Our finding shows that the magnitude of the Seebeck coefficient of graphene can be flexibly changed under a superlattice potential.

Ono, Shota; Zhang, Ming; Noda, Yusuke; Ohno, Kaoru

2014-06-01

416

Visualizing and Diagnosing Coefficients from Geographically Weighted Regression Models  

Microsoft Academic Search

\\u000a Visualizing and interpreting regression coefficients from spatially varying coefficient models, such as geographically weighted\\u000a regression (GWR), can be challenging, given the amount of information the models provide the spatial analyst. Adding to the\\u000a visualization dilemma are various diagnostic tools for checking the coherence of the model. One such diagnostic tool is based\\u000a on decomposing the regression coefficient variance matrix to

David C. Wheeler

417

On the Connection Coefficients of the Chebyshev-Boubaker Polynomials  

PubMed Central

The Chebyshev-Boubaker polynomials are the orthogonal polynomials whose coefficient arrays are defined by ordinary Riordan arrays. Examples include the Chebyshev polynomials of the second kind and the Boubaker polynomials. We study the connection coefficients of this class of orthogonal polynomials, indicating how Riordan array techniques can lead to closed-form expressions for these connection coefficients as well as recurrence relations that define them.

2013-01-01

418

Asymptotic coefficients for one-interacting-level Voigt profiles  

NASA Astrophysics Data System (ADS)

The asymptotic behavior of general Voigt profiles with general width and shift functions has been determined by Cope and Lovett (1987). The resulting asymptotic coefficients are functions of the perturber/radiator mass ratio; also, the coefficients for the one-interacting-level (OIL) profiles proposed by Ward et al. (1974) were studied. In this paper, the behavior of the OIL asymptotic coefficients for large mass ratio values is determined, thereby providing a complete picture of OIL asymptotics for all mass ratios.

Cope, D.; Lovett, R. J.

1988-02-01

419

Strategies on the evaluation of binomial coefficients for all integers  

NASA Astrophysics Data System (ADS)

Binomial coefficients are used in many fields such as computational and applied mathematics, statistics and probability, theoretical physics and chemistry. For accurate numerical results, the correct calculation of these coefficients is very important. We present some new recurrence relationships and numerical methods for the evaluation of binomial coefficients for negative integers. For this purpose, we give some comparisons of the outputs for different computer programming languages in case of negative integers, and also we wrote two new algorithms for computations.

Yükçü, Niyazi; Öztekin, Emin

2013-01-01

420

Weibull crack density coefficient for polydimensional stress states  

NASA Technical Reports Server (NTRS)

A structural ceramic analysis and reliability evaluation code has recently been developed encompassing volume and surface flaw induced fracture, modeled by the two-parameter Weibull probability density function. A segment of the software involves computing the Weibull polydimensional stress state crack density coefficient from uniaxial stress experimental fracture data. The relationship of the polydimensional stress coefficient to the uniaxial stress coefficient is derived for a shear-insensitive material with a random surface flaw population.

Gross, Bernard; Gyekenyesi, John P.

1989-01-01

421

Structural Transformations and Important Coefficients in the North American Economies  

Microsoft Academic Search

This paper assesses a few issues related to the question of finding the so-called important coefficients in an input-output table. Further, these coefficients are located in the corresponding matrices of Canada, the USA and Mexico. Important coefficients are analysed employing graph theoretical tools as well as qualitative input-output concepts and techniques. Empirical results are discussed in terms of the possible

Fidel Aroche-Reyes

2002-01-01

422

Friction coefficient measurement system for winter maintenance vehicles  

Microsoft Academic Search

Real-time measurement of tire-road friction coefficient is extremely valuable for winter road maintenance operations. In winter maintenance, knowledge of tire-road friction coefficient can be used to optimize application of deicing and anti-icing chemicals to the roadway. In this paper, a wheel based tire-road friction coefficient measurement system is developed for snowplows. Unlike a traditional Norse meter, this system is based

G. Erdogan; L. Alexander; R. Rajamani

2008-01-01

423

Solution conformation of a neuronal nicotinic acetylcholine receptor antagonist {alpha}-conotoxin OmIA that discriminates {alpha}3 vs. {alpha}6 nAChR subtypes  

SciTech Connect

{alpha}-Conotoxin OmIA from Conus omaria is the only {alpha}-conotoxin that shows a {approx}20-fold higher affinity to the {alpha}3{beta}2 over the {alpha}6{beta}2 subtype of nicotinic acetylcholine receptor. We have determined a three-dimensional structure of {alpha}-conotoxin OmIA by nuclear magnetic resonance spectroscopy. {alpha}-Conotoxin OmIA has an '{omega}-shaped' overall topology with His{sup 5}-Asn{sup 12} forming an {alpha}-helix. Structural features of {alpha}-conotoxin OmIA responsible for its selectivity are suggested by comparing its surface characteristics with other functionally related {alpha}4/7 subfamily conotoxins. Reduced size of the hydrophilic area in {alpha}-conotoxin OmIA seems to be associated with the reduced affinity towards the {alpha}6{beta}2 nAChR subtype.

Chi, Seung-Wook [Molecular Anti-Cancer Research Center, Division of Molecular Therapeutics, Korea Research Institute of Bioscience and Biotechnology, Yusong P.O. Box 115, Daejon (Korea, Republic of); Kim, Do-Hyoung [Molecular Anti-Cancer Research Center, Division of Molecular Therapeutics, Korea Research Institute of Bioscience and Biotechnology, Yusong P.O. Box 115, Daejon (Korea, Republic of); Olivera, Baldomero M. [Department of Biology, University of Utah, Salt Lake City, UT 84112 (United States); McIntosh, J. Michael [Department of Biology, University of Utah, Salt Lake City, UT 84112 (United States); Department of Psychiatry, University of Utah, Salt Lake City, UT 84112 (United States); Han, Kyou-Hoon [Molecular Anti-Cancer Research Center, Division of Molecular Therapeutics, Korea Research Institute of Bioscience and Biotechnology, Yusong P.O. Box 115, Daejon (Korea, Republic of)]. E-mail: khhan600@kribb.re.kr

2006-06-23

424

MFTF- Alpha +T End Plug Magnet Design.  

National Technical Information Service (NTIS)

The conceptual design of the end-plug magnets for MFTF- alpha +T is described. MFTF- alpha + T is a near-term upgrade of MFTF-B, which features new end plugs to improve performance. The Fusion Engineering Design Center has performed the engineering design...

V. C. ivastava J. A. O'Toole

1983-01-01

425

Automatically processed alpha-track radon monitor  

Microsoft Academic Search

An automatically processed alpha-track radon monitor is provided which includes a housing having an aperture allowing radon entry, and a filter that excludes the entry of radon daughters into the housing. A flexible track registration material is located within the housing that records alpha-particle emissions from the decay of radon and radon daughters inside the housing. The flexible track registration

Langner; G. Harold

1993-01-01

426

Elementary Processes Underlying Alpha Channeling in Tokamaks  

SciTech Connect

Alpha channeling in tokamaks is speculative, but also extraordinarily attractive. Waves that can accomplish this effect have been identified. Key aspects of the theory now enjoy experimental confirmation. This paper will review the elementary processes of wave-particle interactions in plasma that underlie the alpha channeling effect

NM.J. Fisch

2012-06-15

427

A LIQUID-CONTACT SCINTILLATION ALPHA COUNTER  

Microsoft Academic Search

A protected alpha-sensitive scintillation screen has been developed ; which can be used in direct contact with aqueous or organic liquid process ; streams, yielding a measure of the concentrations of alpha-emitting radioisotopes ; in the stream. Concentrations of 0.05 to 10 grams per liter of plutonium can be ; measured with a precision of about plus or minus 20

U. L. Upson; P. E. Brown

1959-01-01

428

The optical spectra of alpha brass  

Microsoft Academic Search

The optical transitions of copper and alpha brass are explained on the basis of the direct transition hypothesis. The studies pertain to the alloys with 10, 20 and 30 atomic per cent zinc concentrations and the changes in transition energy with alloy composition are calculated for some important transitions in alpha brass.

M. P. Das; S. K. Joshi

1972-01-01

429

Alpha rhythm and the pineal gland.  

PubMed

Alpha rhythm is classically described as a bilateral posterior rhythm of substantially constant frequency in the range of 8-13 Hz which is enhanced by mental relaxation and blocked by attention. Since the full expression of alpha rhythm has been shown to occur coincident with puberty, it is possible that the establishment of alpha rhythm is subject to neuroendocrine influences which govern psychosexual maturation. There is ample evidence to indicate that the pineal gland is implicated in cerebral maturation and psychosexual development. Nocturnal plasma melatonin levels have been shown to decline progressively throughout childhood reaching a nadir at puberty. Since administration of melatonin has been reported to block alpha rhythm, it is proposed that the progressive decline in melatonin secretion during childhood facilitates the maturation of the alpha rhythm. Consequently, the presence of alpha rhythm could be used as a neurophysiological marker for the activity of the pineal gland and disorders associated with absent or delayed maturation of the alpha rhythm such as autism, dyslexia, personality disorders, epilepsy, Tourette's syndrome, and schizophrenia might be related to disturbances of pineal melatonin functions in early life. Moreover, since the EEG patterns associated with cerebral immaturity (i.e., slowing, absence of alpha activity) are more pronounced in the left hemisphere, this hypothesis implies differential influence of the pineal gland on hemispheric maturation potentially accounting for the vulnerability of the left hemisphere to cerebral insults. PMID:1304557

Sandyk, R

1992-04-01

430

Automatically processed alpha-track radon monitor  

Microsoft Academic Search

An automatically processed alpha-track radon monitor is provided which includes a housing having an aperture allowing radon entry, and a filter that excludes the entry of radon daughters into the housing. A flexible track registration material is located within the housing that records alpha-particle emissions from the decay of radon and radon daughters inside the housing. The flexible track registration

Langner; G. H. Jr

1991-01-01

431

Preparation of alpha-Substituted Acrylic Acids.  

National Technical Information Service (NTIS)

This invention relates to the preparation of alpha-alkyl and alpha-aryl substituted acrylic acids and esters and more particularly to those derived from fatty acids such as lauric, myristic, palmitic, stearic and oleic acid. The invention also relates to ...

S. Serota W. M. Linfield

1981-01-01

432

Psychiatric Symptoms in Alpha-Mannosidosis  

ERIC Educational Resources Information Center

Alpha-mannosidosis is characterized by mild to moderate intellectual disability (ID), moderate to severe neurosensory hearing loss, frequent infections, psychomotor disturbances and skeletal dysmorphism. For the first time, a panel of nine alpha-mannosidosis patients with psychiatric symptoms is presented. The clinical picture has several…

Malm, D.; Pantel, J.; Linaker, O. M.

2005-01-01

433

Diffusion coefficient of three-dimensional Yukawa liquids  

SciTech Connect

The purpose of this work is an investigation of the diffusion coefficient of the dust component in complex plasma. The computer simulation of the Yukawa liquids was made on the basis of the Langevin equation, which takes into account the influence of buffer plasma on the dust particles dynamics. The Green–Kubo relation was used to calculate the diffusion coefficient. Calculations of the diffusion coefficient for a wide range of the system parameters were performed. Using obtained numerical data, we constructed the interpolation formula for the diffusion coefficient. We also show that the interpolation formula correctly describes experimental data obtained under microgravity conditions.

Dzhumagulova, K. N.; Ramazanov, T. S.; Masheeva, R. U. [IETP, Al Farabi Kazakh National University, 71, al Farabi ave., Almaty 050040 (Kazakhstan)] [IETP, Al Farabi Kazakh National University, 71, al Farabi ave., Almaty 050040 (Kazakhstan)

2013-11-15

434

Measurement of the extinction coefficients of magnetic fluids  

PubMed Central

A novel spectral transmittance approach for measuring the extinction coefficient of magnetic fluids is proposed. The measuring principle and accuracy of the approach are analysed. Experiments are conducted to measure the extinction coefficient of magnetic fluids with different particle volume fractions. The relative uncertainty of experimental data is less than 1.8%. The experimental results indicate that the extinction coefficient of magnetic fluids increases with increase of the volume fraction of suspended magnetic nanoparticles and the optical properties of the particle material have a significant effect on the extinction coefficient of the magnetic fluids.

2011-01-01

435

Alpha 1 antitrypsin phenotypes and alcoholic pancreatitis.  

PubMed Central

Altered frequencies of alpha 1 antitrypsin phenotypes have been reported in patients with chronic pancreatitis, suggesting a possible genetic basis for individual susceptibility to this disease. Alpha 1 antitrypsin phenotypes, with particular regard to alcoholic pancreatitis, were studied. Patients with alcoholic pancreatitis were compared with alcoholic control subjects with no history of pancreatic disease. Serum alpha 1 antitrypsin concentrations were raised in pancreatitis patients sampled within one month of an acute attack of pancreatitis, but otherwise values were similar to those of control subjects. There were no significant differences in alpha 1 antitrypsin phenotypes between alcoholics with pancreatitis and alcoholic control subjects. This study of alpha 1 antitrypsin phenotypes provides no evidence of an inherited susceptibility to alcoholic pancreatitis.

Haber, P S; Wilson, J S; McGarity, B H; Hall, W; Thomas, M C; Pirola, R C

1991-01-01

436

The AGN Fraction in Lyman Alpha Galaxies  

NASA Astrophysics Data System (ADS)

A large fraction of high redshift Lyman-alpha emitters selected through narrow band imaging technique show rest frame equivalent widths (EWs) above 200\\AA. This is beyond the maximum EW expected for normal stellar population. The high EWs can be produced by younger stellar populations, dust, or by type 2 AGNs. We review recent observational progresses on the AGN fraction in high redshift Lyman-alpha searches, including radio, X-ray, and optical spectroscopic observations. Specifically, we show that an upper limit of 5% of the AGN fraction has been obtained based on deep Chandra images. We also present deep IMACS multi-slit spectroscopic observations of 200 candidate z 4.5 Lyman-alpha emitting galaxies selected in the Large Area Lyman Alpha (LALA) narrow band imaging survey Cetus field. This consitutes the largest ever sample of high redshift Lyman-alpha emitters with spectroscopic follow-up.

Wang, Junxian; Rhoads, J.; Malhotra, S.

2007-05-01

437

High redshift Lyman-alpha galaxies.  

NASA Astrophysics Data System (ADS)

A strong Lyman-alpha line enables relatively easy detection of high redshift galaxies. Lyman-alpha galaxies are now known from z=3-6.6. No evolution is discerned in the Lyman-alpha line luminosity function in this redshift range. This implies that the intergalactic medium at z=6 is at least 50% ionized over more than 50% of the volume. Recent continuum detections of these galaxies from HST, MMT and Spitzer are now allowing us to address questions about the nature of these lyman-alpha emitters, their stellar populations and ages. We find that by and large the Lyman-alpha galaxies are young galaxies: dominated by stellar populations that are less than 25 Million years old.

Malhotra, S.; Rhoads, J.

2006-08-01

438

Lyman Alpha Galaxies at High Redshift  

NASA Astrophysics Data System (ADS)

Because strong Lyman alpha emission is expected from young star forming galaxies at high redshift, it offers an efficient tool for identifying these galaxies. The Large Area Lyman Alpha survey is one of the first and largest successful searches for Lyman alpha emitting galaxies at high redshift. In the LALA Bootes field (which lies within the NOAO Deep Wide-Field Survey's Bootes field) we have obtained deep narrowband images covering 1/3 square degree in each of eight filters, sampling redshifts z=4.5, 5.7, and 6.5. We focus here on the higher redshift windows, where we have confirmed a luminous Lyman alpha emitting galaxy at z=6.535 and several others in the z=5.7 window. We discuss the physical properties of these objects, including their contribution to star formation rates and metal production. We also discuss the implications of Lyman alpha galaxy observations at z=6.5 for reionization.

Rhoads, J. E.; Malhotra, S.; Dawson, S.; Dey, A.; Jannuzi, B. T.; Spinrad, H.; Stern, D.; Wang, J. X.; Xu, C.; Brown, M. J. I.; Landes, E.

2004-05-01

439

Specific and dual antagonists of alpha(4)beta(1) and alpha(4)beta(7) integrins.  

PubMed

N-(3,5-Dichlorophenylsulfonyl)-(R)-thioprolyl biarylalanine 10a has been identified as a potent and specific antagonist of the alpha(4)beta(1) integrin. Altering the configuration of thioproline from R to S led to a series of dual antagonists of alpha(4)beta(1) and alpha(4)beta(7), and the N-acetyl analogue 8b was found to be the most potent dual antagonist. A binding site model for alpha(4)beta(1) and alpha(4)beta(7) is proposed to explain the structure-activity relationship. PMID:11755338

Lin, Linus S; Lanza, Thomas; McCauley, Ermenegilda; Van Riper, Gail; Kidambi, Usha; Cao, Jin; Egger, Linda A; Mumford, Richard A; Schmidt, John A; MacCoss, Malcolm; Hagmann, William K

2002-01-21

440

Radiation dose estimation and mass attenuation coefficients of cement samples used in Turkey.  

PubMed

Different cement samples commonly used in building construction in Turkey have been analyzed for natural radioactivity using gamma-ray spectrometry. The mean activity concentrations observed in the cement samples were 52, 40 and 324 Bq kg(-1) for (226)Ra, (232)Th and (40)K, respectively. The measured activity concentrations for these radionuclides were compared with the reported data of other countries and world average limits. The radiological hazard parameters such as radium equivalent activities (Ra(eq)), gamma index (I(gamma)) and alpha index (I(alpha)) indices as well as terrestrial absorbed dose and annual effective dose rate were calculated and compared with the international data. The Ra(eq) values of cement are lower than the limit of 370 Bq kg(-1), equivalent to a gamma dose of 1.5 mSv y(-1). Moreover, the mass attenuation coefficients were determined experimentally and calculated theoretically using XCOM in some cement samples. Also, chemical compositions analyses of the cement samples were investigated. PMID:20018450

Damla, N; Cevik, U; Kobya, A I; Celik, A; Celik, N; Van Grieken, R

2010-04-15

441

Color image enhancement based on the discrete cosine transform coefficient histogram  

NASA Astrophysics Data System (ADS)

This paper presents a new technique for contrast enhancement for color images called histogram shifting with alpha rooting. The novelty in the presented method consists in adapting spatial domain techniques into the transform domain. The benefits of operating in the transform domain include low complexity of computations, ease of viewing, and manipulation of the frequency composition of the image and preservation of the phase information. The combination of the alpha-rooting algorithm, coupled with histogram shifting shows the method's effectiveness for enhancing overexposed images. The contrast enhancement parameter of the algorithm is established automatically based on the entropy of the images. A comprehensive comparative study on image-enhancement algorithms based on discrete cosine transform coefficients is provided. Computer simulations and analysis are provided to compare the enhancement performance of the proposed technique to state of the art approaches. We perform a statistical analysis on the results and quantitatively show that the proposed approach performs well for color image enhancement, which is also validated by ratings from human observers.

Panetta, Karen; Xia, Junjun; Agaian, Sos

2012-04-01

442

Aerosol Angstrom Absorption Coefficient Comparisons during MILAGRO.  

NASA Astrophysics Data System (ADS)

Measurements of aerosol absorption were obtained as part of the MAX-Mex component of the MILAGRO field campaign at site T0 (Instituto Mexicano de Petroleo in Mexico City) by using a 7-channel aethalometer (Thermo- Anderson) during the month of March, 2006. The absorption measurements obtained in the field at 370, 470, 520, 590, 660, 880, and 950 nm were used to determine the aerosol Angstrom absorption exponents by linear regression. Since, unlike other absorbing aerosol species (e.g. humic like substances, nitrated PAHs), black carbon absorption is relatively constant from the ultraviolet to the infrared with an Angstrom absorption exponent of -1 (1), a comparison of the Angstrom exponents can indicate the presence of aerosol components with an enhanced UV absorption over that expected from BC content alone. The Angstrom exponents determined from the aerosol absorption measurements obtained in the field varied from - 0.7 to - 1.3 during the study and was generally lower in the afternoon than the morning hours, indicating an increase in secondary aerosol formation and photochemically generated UV absorbing species in the afternoon. Twelve-hour integrated samples of fine atmospheric aerosols (<0.1micron) were also collected at site T0 and T1 (Universidad Technologica de Tecamac, State of Mexico) from 5 am to 5 pm (day) and from 5 pm to 5 am (night) during the month of March 2006. Samples were collected on quartz fiber filters with high volume impactor samplers. Continuous absorption spectra of these aerosol samples have been obtained in the laboratory from 280 to 900nm with the use of an integrating sphere coupled to a UV spectrometer (Beckman DU with a Labsphere accessory). The integrating sphere allows the detector to collect and spatially integrate the total radiant flux reflected from the sample and therefore allows for the measurement of absorption on highly reflective or diffusely scattering samples. These continuous spectra have also been used to obtain the aerosol Angstrom absorption exponents by linear regression over the entire UV-visible spectral range. These results are compared to results obtained from the absorbance measurements obtained in the field. The differences in calculated Angstrom absorption exponents between the field and laboratory measurements are attributed partly to the differences in time resolution of the sample collection resulting in heavier particle pileup on the filter surface of the 12-hour samples. Some differences in calculated results can also be attributed to the presence of narrow band absorbers below 400 nm that do not fall in the wavelengths covered by the 7 wavelengths of the aethalometer. 1. Marley, N.A., J.S. Gaffney, J.C. Baird, C.A. Blazer, P.J. Drayton, and J.E. Frederick, "The determination of scattering and absorption coefficients of size-fractionated aerosols for radiative transfer calculations." Aerosol Sci. Technol., 34, 535-549, (2001). This work was conducted as part of the Department of Energy's Atmospheric Science Program as part of the Megacity Aerosol Experiment - Mexico City during MILAGRO. This research was supported by the Office of Science (BER), U.S. Department of Energy Grant No. DE-FG02-07ER64329. We also wish to thank Mexican Scientists and students for their assistance from the Instituto Mexicano de Petroleo (IMP) and CENICA.

Marley, N. A.; Marchany-Rivera, A.; Kelley, K. L.; Mangu, A.; Gaffney, J. S.

2007-12-01

443

Folate receptor {alpha} regulates cell proliferation in mouse gonadotroph {alpha}T3-1 cells  

SciTech Connect

We have previously found that the mRNA and protein levels of the folate receptor alpha (FR{alpha}) are uniquely over-expressed in clinically human nonfunctional (NF) pituitary adenomas, but the mechanistic role of FR{alpha} has not fully been determined. We investigated the effect of FR{alpha} over-expression in the mouse gonadotroph {alpha}T3-1 cell line as a model for NF pituitary adenomas. We found that the expression and function of FR{alpha} were strongly up-regulated, by Western blotting and folic acid binding assay. Furthermore, we found a higher cell growth rate, an enhanced percentage of cells in S-phase by BrdU assay, and a higher PCNA staining. These observations indicate that over-expression of FR{alpha} promotes cell proliferation. These effects were abrogated in the same {alpha}T3-1 cells when transfected with a mutant FR{alpha} cDNA that confers a dominant-negative phenotype by inhibiting folic acid binding. Finally, by real-time quantitative PCR, we found that mRNA expression of NOTCH3 was up-regulated in FR{alpha} over-expressing cells. In summary, our data suggests that FR{alpha} regulates pituitary tumor cell proliferation and mechanistically may involve the NOTCH pathway. Potentially, this finding could be exploited to develop new, innovative molecular targeted treatment for human NF pituitary adenomas.

Yao, Congjun; Evans, Chheng-Orn [Department of Neurosurgery and Laboratory of Molecular Neurosurgery and Biotechnology, Emory University, School of Medicine, Atlanta, Georgia (United States)] [Department of Neurosurgery and Laboratory of Molecular Neurosurgery and Biotechnology, Emory University, School of Medicine, Atlanta, Georgia (United States); Stevens, Victoria L. [Epidemiology and Surveillance Research, American Cancer Society, Atlanta, Georgia (United States)] [Epidemiology and Surveillance Research, American Cancer Society, Atlanta, Georgia (United States); Owens, Timothy R. [Emory University, School of Medicine, Atlanta, Georgia (United States)] [Emory University, School of Medicine, Atlanta, Georgia (United States); Oyesiku, Nelson M., E-mail: noyesik@emory.edu [Department of Neurosurgery and Laboratory of Molecular Neurosurgery and Biotechnology, Emory University, School of Medicine, Atlanta, Georgia (United States)

2009-11-01

444

Is There Diffuse Lyman-alpha Emission Around Lyman-alpha Galaxies?  

NASA Astrophysics Data System (ADS)

The Lyman alpha line is resonantly scattered, thus neutral gas within a galaxy can scatter these photons out into a diffuse halo. Understanding what fraction of the Lyman alpha photons do not make it directly out of the central galaxy is crucial to interpret high-redshift spectroscopic detections, or lack thereof, of Lyman alpha. However, thus far these halos have only been observed in a few instances. We study these halos at z=4.5 by coadding narrow-band images containing the Lyman-alpha emission line for a sample of 200 spectroscopically confirmed Lyman-alpha galaxies. Thus stacking allows us to probe to very faint surface brightness levels. We compare the Lyman alpha surface brightness distribution of Lyman-alpha-selected galaxies with Lyman-break galaxies to see if these two samples differ in their general nature.

Smith, Brent Mathew; Malhotra, S.; Rhoads, J.; Finkelstein, S.; Zheng, Z.; Wang, J.

2012-01-01

445

G alpha 12 and G alpha 13 subunits define a fourth class of G protein alpha subunits.  

PubMed Central

Heterotrimeric guanine nucleotide-binding regulatory proteins (G proteins) are central to the signaling processes of multicellular organisms. We have explored the diversity of the G protein subunits in mammals and found evidence for a large family of genes that encode the alpha subunits. Amino acid sequence comparisons show that the different alpha subunits fall into at least three classes. These classes have been conserved in animals separated by considerable evolutionary distances; they are present in mammals, Drosophila, and nematodes. We have now obtained cDNA clones encoding two murine alpha subunits, G alpha 12 and G alpha 13, that define a fourth class. The translation products are predicted to have molecular masses of 44 kDa and to be insensitive to ADP-ribosylation by pertussis toxin. They share 67% amino acid sequence identity with each other and less than 45% identity with other alpha subunits. Their transcripts can be detected in every tissue examined, although the relative levels of the G alpha 13 message appear somewhat variable. Images

Strathmann, M P; Simon, M I

1991-01-01

446

Binary-YORP Coefficients for Known Asteroid Shapes  

NASA Astrophysics Data System (ADS)

The binary YORP (bYORP) effect has been hypothesized to be a significant factor in the evolution of near-Earth binary asteroid systems (Cuk and Burns, Icarus, v.176, pp.418-431, 2005; McMahon and Scheeres, CMDA, v.106, pp.261-300, 2010). However, understanding of the coefficient values for realistic asteroid shapes is lacking due to the small number of shape models available for the generally smaller secondary asteroids. Until now, we have only calculated the coefficients based on the shape of 1999 KW4 Beta, although various studies by other authors have computed coefficients for artificially generated asteroids based on Gaussian Spheres and some shape models without self-shadowing (Steinberg and Sari, The Astronomical Journal, v.141, pp.55-64, 2011). We also scaled the 1999 KW4 Beta coefficients to other binary systems with no knowledge of the other systems' secondary shapes in order to make evolutionary predictions (McMahon and Scheeres, Icarus Vol. 209, pp 494-509, 2010). In this study, we compute the bYORP coefficient for a range of asteroid shapes, using these as a stand-in for actual secondaries. This allows us to circumvent the lack of information on binary asteroid secondaries and to develop a richer database of realistic coefficients. While this approach may miss some key features of binary secondaries, at the least it provides some statistics on the expected variability of the bYORP coefficient. We analyze all available asteroid shape models on the PDS-SBN, including radar-based shape models and models estimated from past spacecraft missions. The coefficients are computed with an updated algorithm that includes the effects of self-shadowing. We also present the coefficients for perturbed versions of the available shape models, which give effective error bars to the computed coefficients due to inexact shape models. Finally, we discuss the dynamical implications of the derived bYORP coefficients on binary asteroid evolution.

McMahon, Jay W.; Scheeres, D. J.

2012-10-01

447

Human topoisomerase II-alpha is highly expressed in sinonasal-inverted papilloma, but not in inflammatory polyp.  

PubMed

Sinonasal-inverted papilloma is a benign tumour with a high rate of recurrence, but possible malignant transformation. Therefore, investigation of predisposition to malignant transformation of sinonasal-inverted papilloma gives clinicians the opportunity for adequate treatment. Topoisomerase II-alpha (topoII-alpha) and Ki67 are markers of cell proliferation in both normal and neoplastic tissues and its level o expression could be used as a predictive parameter. Our goal was to investigate by immunochemistry the expression level of topoII-in inverted papilloma, inflammatory nasal polyp and normal sinonasal epithelium and to compare it with expression level of Ki67. TopoI alpha nuclear immunostaining showed a differential positivity in the investigated cases. The topoII-alpha index was 30.6 +/- 12.8 in inverte papilloma, 10.7 +/- 6.6 in the adjacent epithelium of inverted papilloma, but only 2.3 +/- 2.0 in the normal sinonasal epithelium. The differences in topoII-alpha expression between inverted papilloma and normal sinonasal epithelia were statistically significant. In inflammatory nasal polyp group, topoII-alpha index was 2.4 +/- 2.1, and the difference in the topoII-alpha index between inverted papilloma and inflammatory polyp group was also statistically significant. Nuclear immunostaining for Ki67 followed a similar variation. The Ki67 index was 50.0 +/- 20. in inverted papilloma, 9.0 +/- 6.6 in the adjacent epithelium of inverted papilloma and 2.4 +/- 0.9 in normal sinonasal epithelium. The differences in Ki67 expression between inverted papilloma and either adjacent or normal sinonasal epithelia were statistically significant. Significant correlation coefficients were found between topoII-alpha and epithelial thickness (r = 0.70, P > 0.0001), and between Ki67 index and epithelial thickness (r = 0.71, P> 0.0001). In the inflammatory nasal polyp group Ki67 index was 5.9 +/- 3.4. The difference in th Ki67 index between inverted papilloma and inflammatory nasal polyp groups was statistically significant. Significant correlation coefficient was found between topoII-alpha index and Ki67 index in inverted papilloma (r = 0.42, P > 0.05). These results suggest that the inverte papilloma contains a significantly higher cell population with proliferative activity by comparison with normal sinonasal and inflammatory polyp epithelia, showing a significant correlation between topoII-alpha and Ki67 expression, and indicating that topoII-alpha could be a independent prognostic factor for a putative malignant transformation. PMID:18544048

Hadar, Tuvia; Shvero, Jacob; Yaniv, Eitan; Shvili, Itzhac; Leabu, Mircea; Koren, Rumelia

2008-01-01

448

Involvement of central alpha1-adrenoceptors on renal responses to central moxonidine and alpha-methylnoradrenaline.  

PubMed

Moxonidine (alpha2-adrenoceptor/imidazoline receptor agonist) injected into the lateral ventricle induces diuresis, natriuresis and renal vasodilation. Moxonidine-induced diuresis and natriuresis depend on central imidazoline receptors, while central alpha1-adrenoceptors are involved in renal vasodilation. However, the involvement of central alpha1-adrenoceptors on diuresis and natriuresis to central moxonidine was not investigated yet. In the present study, the effects of moxonidine, alpha-methylnoradrenaline (alpha2-adrenoceptor agonist) or phenylephrine (alpha1-adrenoceptor agonist) alone or combined with previous injections of prazosin (alpha1-adrenoceptor antagonist), yohimbine or RX 821002 (alpha2-adrenoceptor antagonists) intracerebroventricularly (i.c.v.) on urinary sodium, potassium and volume were investigated. Male Holtzman rats (n = 5-18/group) with stainless steel cannula implanted into the lateral ventricle and submitted to gastric water load (10% of body weight) were used. Injections of moxonidine (20 nmol) or alpha-methylnoradrenaline (80 nmol) i.c.v. induced natriuresis (196 +/- 25 and 171 +/- 30, respectively, vs. vehicle: 101 +/- 9 microEq/2 h) and diuresis (9.0 +/- 0.4 and 12.3 +/- 1.6, respectively, vs. vehicle: 5.2 +/- 0.5 ml/2 h). Pre-treatment with prazosin (320 nmol) i.c.v. abolished the natriuresis (23 +/- 4 and 76 +/- 11 microEq/2 h, respectively) and diuresis (5 +/- 1 and 7.6 +/- 0.8 ml/2 h, respectively) produced by i.c.v. moxonidine or alpha-methylnoradrenaline. RX 821002 (320 nmol) i.c.v. abolished the natriuretic effect of alpha-methylnoradrenaline, however, yohimbine (320 nmol) did not change renal responses to moxonidine. Phenylephrine (80 nmol) i.c.v. induced natriuresis and kaliuresis that were blocked by prazosin. Therefore, the present data suggest that moxonidine and alpha-methylnoradrenaline acting on central imidazoline receptors and alpha2-adrenoceptors, respectively, activate central alpha1-adrenergic mechanisms to increase renal excretion. PMID:19326476

de Andrade, Carina A F; de Andrade, Glaucia M F; De Paula, Patricia M; De Luca, Laurival A; Menani, José V

2009-04-01

449

Targeted alpha therapy: part I.  

PubMed

The possibility of pinpointing biological targets, and thereby potentially targeting and eradicating small tumors or even single cancer cells, is a tantalizing concept that has been discussed since the magic-bullet concept was first presented by Paul Erlich in the beginning of the 20th century in connection with his work on tissue staining for histological examinations and the work by Kohler and Milstein on antibody production published in 1975. This concept now seems feasible through the use of highly specific targeting constructs, chemical labeling of radioactive substances to these targeting constructs that results in high specific activities, radioimmunocomplexes with good stability even after injection, and the use of radionuclides emitting alpha( ?)-particles having exceedingly high ionizing density and, therefore, a high probability of killing cells along its track in tissue. The short range of the emitted ?-particles makes them even more interesting by minimizing unwanted irradiation of normal tissue surrounding the targeted cancer cells of interest, assuming high specificity of the targeting construct and good stability of the chemical bonds between the targeting construct and the ?-particle emitter. Targeted Alpha Therapy (TAT), in which an ?-particle emitting radionuclide is specifically directed to the biological target, is gaining more attention as new targets, targeting constructs, chemical labeling techniques, and ?-particle emitters are, respectively, identified, constructed, developed, and made available. Results and improvements are now being published at an increasing rate and the number of conceivable applications is expanding, especially in the field of cancer treatment. Therefore, it is of utmost importance to provide an overview of the overall progress in the research field of TAT on a regular basis. However, problems such as limited or delayed diffusion of the ?-radioimmunocomplex and inhomogeneous activity distributions in the targeted tumors, resulting in inhomogeneous absorbed dose distributions, are challenges that need to be addressed. These challenges need to be overcome before TAT becomes a standard treatment for diseases such as micrometastatic cancer. Hopefully, when enough funding will be provided and, hence, more treatment strategies of TAT will reach the clinical level the importance to conduct controlled, randomized trials with sufficient patient numbers, enabling statistical significance to occur must be emphasized in order to be able to properly compare and evaluate different approaches. In this issue, of the two hot-topic issues for targeted alpha therapy, articles discuss the recent developments in radionuclide availability, biomolecular targeting, labeling chemistry, and dosimetry for the most promising ?-particle emitters. In the first article, Zalutsky et al. discuss the possibilities and limitations of using the promising ?-particle emitter, 211At, and emphasize the need for funding new cyclotrons and prioritizing beam-times of already existing cyclotrons to improve the availability of 211At. Haddad et al. describe the status of the ARRONAX project through which a number of important nuclear medicine radionuclides will be produced, including some of those suitable for TAT. Relevant targeting constructs and their associated antigens used today and candidates for use in the future are discussed by Olafsen et al. in the third article. The next article, by Scott Wilbur, discusses chemical and radiochemical issues of radiolabeling using ?-particle emitting radionuclides, e.g. factors that are important in selecting chelation or bonding reagents during the development of ?-particle emitting radiopharmaceuticals. Lindegren at al. continue the discussion of chemical considerations in the following article, but focuses on pre-targeting techniques, which will hopefully enhance both the activity distribution in the targeted tumor and the tumor-to-normal tissue absorbed dose ratio. The two final articles discuss different aspects of the dosimetry related to ?-particles. The art

Elgqvist, Jorgen

2011-07-01

450

Expression of alpha 1-adrenoceptor subtypes in rat tissues: implications for alpha 1-adrenoceptor classification.  

PubMed

We report here the mapping of the mRNA distribution of three different alpha 1-adrenoceptor subtypes (alpha 1b, alpha 1c and alpha 1d) in various rat tissues. cDNA fragments covering the region from the fifth to seventh putative transmembrane spanning domains of these three alpha 1-adrenoceptor subtypes were generated from rat hippocampus using reverse transcription coupled to polymerase chain reaction (PCR). These three alpha 1-adrenoceptor cloned cDNA fragments were then used as subtype-selective cDNA probes in Northern blot analysis. Of the three specific DNA probes only the rat alpha 1b-adrenoceptor probe hybridized to mRNA of rat liver. The rat alpha 1c-adrenoceptor probe hybridized to a mRNA species of 3.7 kb in tissues that have been reported to contain the classical pharmacologically-defined alpha 1A-adrenoceptor such as hippocampus, vas deferens, lung and salivary gland. Also, a major mRNA transcript of 2.7 kb was detected in hippocampus, vas deferens and lung, using the rat alpha 1d-adrenoceptor probe. In addition, pharmacological characterization of [3H]prazosin binding to three stably transfected mammalian cell-lines expressing one of the three alpha 1-adrenoceptor subtypes cloned to date (namely, alpha 1b--of the hamster smooth muscle DDT1-MF2 cell-line, the bovine brain alpha 1c--and the rat cerebral cortical alpha 1d-adrenoceptors) was performed. Of the three cloned alpha 1-adrenoceptor subtypes that alpha 1c-adrenoceptor showed a similar pharmacological profile to that of the classical alpha 1A-adrenoceptor of rat salivary gland. Our data on the pharmacological profile and expression pattern of the alpha 1c-adrenoceptor indicate, in contrast to earlier claims (Schwinn et al., J. Biol. Chem. 265, 1990), that this subtype is in fact the classical pharmacologically-defined alpha 1A-adrenoceptor subtype. PMID:7957636

Faure, C; Pimoule, C; Arbilla, S; Langer, S Z; Graham, D

1994-07-15

451

40 CFR 721.10491 - Benzenepropanal,.alpha.-methyl-.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Benzenepropanal,.alpha.-methyl-. 721.10491 Section...Substances § 721.10491 Benzenepropanal,.alpha.-methyl-. (a) Chemical substance...substance identified as benzenepropanal,.alpha.-methyl- (PMN P-05-55;...

2013-07-01

452

Genetics Home Reference: Mucolipidosis II alpha/beta  

MedlinePLUS

... literature OMIM Genetic disorder catalog Conditions > Mucolipidosis II alpha/beta On this page: Description Genetic changes Inheritance ... definitions Reviewed June 2014 What is mucolipidosis II alpha/beta? Mucolipidosis II alpha/beta (also known as ...

453

Theoretical response of a ZnS(Ag) scintillation detector to alpha-emitting sources and suggested applications  

SciTech Connect

The classic problem of alpha absorption is discussed in terms of the quantitative determination of the activity of weightless alpha sources and the specific alpha activity of extended sources accounting for absorption in the source medium and the window of a large area ZnS(Ag) scintillation detector. The relationship for the expected counting rate gamma of a monoenergetic source of active area A, specific alpha activity C, and thickness H that exceeds the effective mass density range Rs of the alpha particle in the source medium can be expressed by a quadratic equation in the window thickness x when this source is placed in direct contact with the window of the ZnS(Ag) detector. This expression also gives the expected counting rate of a finite detector of sensitive area A exposed to an infinite homogeneous source medium. Counting rates y obtained for a source separated from a ZnS(Ag) detector by different thicknesses x of window material can be used to estimate parameter values in the quadratic equation, y = a + bx + cx2. The experimental value determined for the coefficient b provides a direct estimation of the specific activity C. This coefficient, which depends on the ratio of the ranges in the source medium and detector window and not the ranges themselves, is essentially independent of the energy of the alpha particle. Although certain experimental precautions must be taken, this method for estimating the specific activity C is essentially an absolute method that does not require the use of standards, special calibrations, or complicated radiochemical procedures. Applications include the quantitative determination of Rn and progeny in air, water, and charcoal, and the measurement of the alpha activity in soil and on air filter samples.

Skrable, K.W.; Phoenix, K.A.; Chabot, G.E.; French, C.S.; Jo, M.; Falo, G.A. (Univ. of Lowell, MA (USA))

1991-03-01

454

Theoretical response of a ZnS(Ag) scintillation detector to alpha-emitting sources and suggested applications.  

PubMed

The classic problem of alpha absorption is discussed in terms of the quantitative determination of the activity of "weightless" alpha sources and the specific alpha activity of extended sources accounting for absorption in the source medium and the window of a large area ZnS(Ag) scintillation detector. The relationship for the expected counting rate gamma of a monoenergetic source of active area A, specific alpha activity C, and thickness H that exceeds the effective mass density range Rs of the alpha particle in the source medium can be expressed by a quadratic equation in the window thickness x when this source is placed in direct contact with the window of the ZnS(Ag) detector. This expression also gives the expected counting rate of a finite detector of sensitive area A exposed to an infinite homogeneous source medium. Counting rates y obtained for a source separated from a ZnS(Ag) detector by different thicknesses x of window material can be used to estimate parameter values in the quadratic equation, y = a + bx + cx2. The experimental value determined for the coefficient b provides a direct estimation of the specific activity C. This coefficient, which depends on the ratio of the ranges in the source medium and detector window and not the ranges themselves, is essentially independent of the energy of the alpha particle. Although certain experimental precautions must be taken, this method for estimating the specific activity C is essentially an absolute method that does not require the use of standards, special calibrations, or complicated radiochemical procedures. Applications include the quantitative determination of Rn and progeny in air, water, and charcoal, and the measurement of the alpha activity in soil and on air filter samples. PMID:1995511

Skrable, K W; Phoenix, K A; Chabot, G E; French, C S; Jo, M; Falo, G A

1991-03-01

455

Model for alpha particle induced nuclear reactions: ⁹³Nb(. cap alpha. ,x. cap alpha. ypzn) from 40--140 MeV  

Microsoft Academic Search

A comprehensive model is introduced for alpha particle induced nuclear reactions. Five different mechanisms are examined and discussed. These include inelastic scattering of the incident alpha particle, nucleon pickup, binary fragmentation, dissolution of the alpha in the nuclear field, and preequilibrium processes initiated by alpha-nucleon collisions. A series of experiments was performed to measure the excitation functions of many nuclides

E. Gadioli; E. Gadioli-Erba; J. J. Hogan; B. V. Jacak

1984-01-01

456

Cloning and targeted mutations of G alpha 7 and G alpha 8, two developmentally regulated G protein alpha-subunit genes in Dictyostelium.  

PubMed Central

GTP-binding protein (G protein)-mediated signal transduction pathways play essential roles during the aggregation and differentiation process of Dictyostelium. In addition to the five known G protein alpha-subunit genes, we recently identified three novel alpha-subunit genes, G alpha 6, G alpha 7, and G alpha 8, using the polymerase chain reaction technique. We present here a more complete analysis of G alpha 7 and G alpha 8. The cDNAs of these two genes were cloned, and their complete nucleotide sequences were determined. Sequence analyses indicate that G alpha 8 possesses some unusual features. It lacks the "TCATDT" motif, a sequence of amino acids highly conserved among G alpha subunits, and has an additional 50 amino acids at its C-terminus consisting of long stretches of asparagine. Moreover, G alpha 8 is unusually resistant to protease digestion, which may indicate a slow GTP hydrolysis rate. The possible functions of these alpha-subunits were assessed by generating mutants lacking G alpha 7 or G alpha 8 by gene targeting through homologous recombination and by overexpressing G alpha 7 or G alpha 8 protein. Overexpression of G alpha 7 resulted in abnormal morphogenesis starting at the slug stage, whereas analysis of the other strains failed to reveal any obvious growth or developmental defects under either normal or stressful conditions. The implications of these results are discussed. Images

Wu, L; Gaskins, C; Zhou, K; Firtel, R A; Devreotes, P N

1994-01-01

457

Single particle tracking of alpha7 nicotinic AChR in hippocampal neurons reveals regulated confinement at glutamatergic and GABAergic perisynaptic sites.  

PubMed

Alpha7 neuronal nicotinic acetylcholine receptors (alpha7-nAChR) form Ca(2+)-permeable homopentameric channels modulating cortical network activity and cognitive processing. They are located pre- and postsynaptically and are highly abundant in hippocampal GABAergic interneurons. It is unclear how alpha7-nAChRs are positioned in specific membrane microdomains, particularly in cultured neurons which are devoid of cholinergic synapses. To address this issue, we monitored by single particle tracking the lateral mobility of individual alpha7-nAChRs labeled with alpha-bungarotoxin linked to quantum dots in live rat cultured hippocampal interneurons. Quantitative analysis revealed different modes of lateral diffusion of alpha7-nAChR dependent on their subcellular localization. Confined receptors were found in the immediate vicinity of glutamatergic and GABAergic postsynaptic densities, as well as in extrasynaptic clusters of alpha-bungarotoxin labeling on dendrites. alpha7-nAChRs avoided entering postsynaptic densities, but exhibited reduced mobility and long dwell times at perisynaptic locations, indicative of regulated confinement. Their diffusion coefficient was lower, on average, at glutamatergic than at GABAergic perisynaptic sites, suggesting differential, synapse-specific tethering mechanisms. Disruption of the cytoskeleton affected alpha7-nAChR mobility and cell surface expression, but not their ability to form clusters. Finally, using tetrodotoxin to silence network activity, as well as exposure to a selective alpha7-nAChR agonist or antagonist, we observed that alpha7-nAChRs cell surface dynamics is modulated by chronic changes in neuronal activity. Altogether, given their high Ca(2+)-permeability, our results suggest a possible role of alpha7-nAChR on interneurons for activating Ca(2+)-dependent signaling in the vicinity of GABAergic and glutamatergic synapses. PMID:20634896

Bürli, Thomas; Baer, Kristin; Ewers, Helge; Sidler, Corinne; Fuhrer, Christian; Fritschy, Jean-Marc

2010-01-01

458

A Cross-Country Comparison of Okun's Coefficient  

Microsoft Academic Search

In this paper Okun's law is tested for the G7 countries in order to compare the responsiveness of unemployment to economic growth. Cyclical unemployment and output are extracted using Harvey's structural time series model. Okun's coefficient is estimated by OLS, rolling OLS, and SUR. The coefficient seems to be highest for North America and lowest for Japan, a result that

Imad A. Moosa

1997-01-01

459

Estimating Regression Coefficients by Minimizing the Dispersion of the Residuals  

Microsoft Academic Search

An appealing approach to the problem of estimating the regression coefficients in a linear model is to find those values of the coefficients which make the residuals as small as possible. We give some measures of the dispersion of a set of numbers, and define our estimates as those values of the parameters which minimize the dispersion of the residuals.

Louis A. Jaeckel

1972-01-01

460

Stability of constant coefficient linear singular systems with delay  

Microsoft Academic Search

In this paper, the general class of singular systems with delay and linear constant coefficient singular systems with delay are discussed. First, several definitions of stability are presented for singular systems with delay, and general sufficient stability conditions and instability conditions are obtained. Second, stability and instability are analyzed for linear constant coefficient singular systems with delay.

Yuanqing Li; Weizheng Feng; Yongqing Liu

2000-01-01

461

Calculation of fusion product angular correlation coefficients for fusion plasmas  

SciTech Connect

The angular correlation coefficients for fusion products are calculated in the cases of Maxwellian and beam-target plasmas. Measurement of these coefficients as a localized ion temperature or fast-ion diagnostic is discussed. 8 refs., 7 figs., 1 tab.

Murphy, T.J.

1987-08-01

462

Heat-transfer coefficients in agitated vessels. Latent heat models  

Microsoft Academic Search

Latent heat models were developed to calculate heat-transfer coefficients in agitated vessels for two cases: (1) heating with a condensable fluid flowing through coils and jackets; (2) vacuum reflux cooling with an overhead condenser. In either case the mathematical treatment, based on macroscopic balances, requires no iterative schemes. In addition to providing heat-transfer coefficients, the models predict flow rates of

Enio Kumpinsky

1996-01-01

463

Air-sea bulk transfer coefficients in diabatic conditions  

Microsoft Academic Search

On the basis of recent data for the roughness Reynolds number of the sea surface, and using the Owen-Thomson theory on the transfers of heat and mass between a rough surface and the flow above it, the bulk transfer coefficients of the sea surface have been estimated. For a reference height of 10 m, the neutral-lapse transfer coefficient for water

Junsei Kondo

1975-01-01

464

Evaluation and measures to increase performance coefficient of hydrokinetic turbines  

Microsoft Academic Search

In this study was presented the valid equations for energy conversion system from water currents analogous to wind power system. Hydrokinetic technology may be divided into two categories such as horizontal and vertical system. Application of the systems is possible to marine, and river currents. Each system has different performance coefficient. Hydrokinetic energy conversion systems shows lower power coefficient. The

Mukrimin Sevket Guney

2011-01-01

465

Biases and Standard Errors of Standardized Regression Coefficients  

ERIC Educational Resources Information Center

The paper obtains consistent standard errors (SE) and biases of order O(1/n) for the sample standardized regression coefficients with both random and given predictors. Analytical results indicate that the formulas for SEs given in popular text books are consistent only when the population value of the regression coefficient is zero. The sample…

Yuan, Ke-Hai; Chan, Wai

2011-01-01

466

Stiffness and viscous coefficient characteristics for ergonomics chair design  

Microsoft Academic Search

This report presents a study of stiffness, ks and viscous coefficient, c characteristic on a developed chair apparatus namely Pneumatic Actuated Seating System (PASS). The stiffness and viscous coefficient characteristics represents the spring and damping function respectively. These two characteristics are emulated from spring-damping model to thirty six intelligent pneumatic actuators on PASS. These attributes will facilitate in investigation of

Ahmad Athif Mohd Faudzi; Koichi Suzumori

2011-01-01

467

Coinvariants for Lattice VOAs and q-Supernomial Coefficients  

NASA Astrophysics Data System (ADS)

We propose an alternative definition of the q-supernomial coefficients as the characters of coinvariants for the one-dimensional lattice vertex operator algebras. This provides a new formula for the q-supernomial coefficients. We also prove that the spaces of the coinvariants form a bundle over the configuration space of complex points on Riemann surfaces (the configuration space includes the diagonals).

Feigin, B. L.; Loktev, S. A.; Tipunin, I. Yu.

468

van der Waals coefficients for positronium-atom interactions  

SciTech Connect

The van der Waals coefficients for positronium interactions with a number of rare gases (He, Ne, Ar, Kr, and Xe) and alkali-metal atoms (Li, Na, K, and Rb) are estimated using a variety of ab initio and semiempirical methods. Dispersion coefficients are also presented for atomic hydrogen and a number of rare-gas and alkali-metal atoms for validation purposes.

Mitroy, J.; Bromley, M. W. J. [Faculty of SITE, Northern Territory University, Darwin, Northern Territory 0909, (Australia)

2003-09-01

469

Bispectrum Mel-frequency Cepstrum Coefficients for Robust Speaker Identification  

Microsoft Academic Search

In this paper, we introduce the use of bispectrum slice for mel-frequency cepstrum coefficients as robust text- independent speaker identification. The main advantage of using the bispectrum is to be able to suppress additive Gaussian noise while preserving the phase information of the signal. In order to obtain cepstral coefficients, features of the speech signal are extracted by mel-frequency filter

Tolga Esat Özkurt; Tayfun Akgül

470

Detection of Landmines from Acoustic Images Based on Cepstral Coefficients  

Microsoft Academic Search

This paper introduces a cepstral approach for the automatic detection of landmines from acoustic images. This approach is based on treating the problem of landmine detection as a pattern recognition problem. Cepstral features are extracted from a group of landmine images which are transformed first to 1-D signals by lexicographic ordering. Mel frequency cepstral coefficients (MFCCs) and polynomial shaping coefficients

Fathi E. Abd El-Samie