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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.



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.



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



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.



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



Exact Distributions of Intraclass Correlation and Cronbach's Alpha with Gaussian Data and General Covariance  

ERIC Educational Resources Information Center

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

Kistner, Emily O.; Muller, Keith E.



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.



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



A Direct Latent Variable Modeling Based Method for Point and Interval Estimation of Coefficient Alpha  

ERIC Educational Resources Information Center

A direct approach to point and interval estimation of Cronbach's coefficient alpha for multiple component measuring instruments is outlined. The procedure is based on a latent variable modeling application with widely circulated software. As a by-product, using sample data the method permits ascertaining whether the population discrepancy…

Raykov, Tenko; Marcoulides, George A.



Coefficient Alpha: A Reliability Coefficient for the 21st Century?  

ERIC Educational Resources Information Center

Coefficient alpha is almost universally applied to assess reliability of scales in psychology. We argue that researchers should consider alternatives to coefficient alpha. Our preference is for structural equation modeling (SEM) estimates of reliability because they are informative and allow for an empirical evaluation of the assumptions…

Yang, Yanyun; Green, Samuel B.



Coefficient Alpha Bootstrap Confidence Interval under Nonnormality  

ERIC Educational Resources Information Center

Three different bootstrap methods for estimating confidence intervals (CIs) for coefficient alpha were investigated. In addition, the bootstrap methods were compared with the most promising coefficient alpha CI estimation methods reported in the literature. The CI methods were assessed through a Monte Carlo simulation utilizing conditions…

Padilla, Miguel A.; Divers, Jasmin; Newton, Matthew



Commentary on Coefficient Alpha: A Cautionary Tale  

ERIC Educational Resources Information Center

The general use of coefficient alpha to assess reliability should be discouraged on a number of grounds. The assumptions underlying coefficient alpha are unlikely to hold in practice, and violation of these assumptions can result in nontrivial negative or positive bias. Structural equation modeling was discussed as an informative process both to…

Green, Samuel B.; Yang, Yanyun



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



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.



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.



The number of nonzero binomial coefficients modulo p^alpha  

E-print Network

In 1947 Fine obtained an expression for the number a_p(n) of binomial coefficients on row n of Pascal's triangle that are nonzero modulo p. One can set up a recurrence for the number of integers 0 s theorem renders this recurrence as a generalization of Fine's theorem, giving a way to compute the number a_{p^alpha}(n) of nonzero binomial coefficients modulo p^alpha. From the recurrence we obtain an expression for a_{p^alpha}(n) in terms of the number of occurrences of various words in the base-p representation of n.

Rowland, Eric S



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



Coefficient Alpha as an Estimate of Test Reliability Under Violation of Two Assumptions  

Microsoft Academic Search

Through use of computer simulation, the central tendency and variability of coefficient alpha were examined under violation of two assumptions made in the derivation of the formula. When assumptions were satisfied, the mean value of coefficient alpha was extremely close to the population reliability coefficient, but values were highly variable. This result was independent of the shape of the population

Donald W. Zimmerman; Bruno D. Zumbo; Coralie Lalonde



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



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)



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



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



A new method for determining 'rotational' piezooptic coefficients with reference to TGS + L - alpha-alanine crystals  

Microsoft Academic Search

A method is proposed for determining the 'rotational' piezooptic coefficients from changes in the optical axis orientation. The efficiency of the method is demonstrated for triglycine sulfate + L - alpha-alanine crystals. Temperature anomalies in the piezooptic coefficients and in the angle between the optical axes induced by mechanical stresses are identified and discussed.

B. G. Mytsyk; B. V. Osyka; A. S. Andrushchak; R. S. Petrushko



Study of the absorption coefficient of alpha particles to lower hybrid waves in tokamak  

SciTech Connect

Part of the energy of the Lower Hybrid (LH) waves may be absorbed by the ? particles via the so-called perpendicular landau damping mechanism, which depends on various parameters of fusion reactors and the LH waves. In this article, we calculate the absorption coefficient ?{sub ?} of LH waves due to ? particles. Results show that, the ?{sub ?} increases with the parallel refraction index n{sub ?} while deceases with increasing the frequency of LH waves ?{sub LH} over a wide range. Higher background plasma temperature and toroidal magnetic field will increase the absorption, and there is a peak value of ?{sub ?} when n{sub e}?8×10{sup 19}m{sup ?3} for ITER-like scenario. The thermal corrections to the cold plasma dispersion relation will change the damping rate to a certain extent under some specific conditions. We have also evaluated the fraction of LH power absorbed by the alpha particles, ? ? 0.47% and 4.1% for an LH frequency of 5 GHz and 3.7 GHz respectively for ITER-like scenario. This work gives the effective reference for the choice of parameters of future fusion reactors.

Wang, Jianbing, E-mail:; Zhang, Xianmei, E-mail:; Yu, Limin, E-mail:; Zhao, Xiang, E-mail: [Department of Physics, East China University of Science and Technology, P.O. Box 385, Shanghai 200237 (China)



A Monte Carlo Study of Eight Confidence Interval Methods for Coefficient Alpha  

ERIC Educational Resources Information Center

The purpose of this research is to examine eight of the different methods for computing confidence intervals around alpha that have been proposed to determine which of these, if any, is the most accurate and precise. Monte Carlo methods were used to simulate samples under known and controlled population conditions. In general, the differences in…

Romano, Jeanine L.; Kromrey, Jeffrey D.; Hibbard, Susan T.



Influence of plasma parameters on the absorption coefficient of alpha particles to lower hybrid waves in tokamaks  

NASA Astrophysics Data System (ADS)

In tokamaks, fusion generated ? particles may absorb lower hybrid (LH) wave energy, thus reducing the LH current drive efficiency. The absorption coefficient ?? of LH waves due to ? particles changing with some typical parameters is calculated in this paper. Results show that ?? increases with the parallel refraction index n ?, while decreases with the frequency of LH waves ? over a wide range. Higher background plasma temperature and toroidal magnetic field will increase the absorption. The absorption coefficient ?? increases with n e when n e ? 8 × 1019 m-3, while decreases with n e when n e becomes larger, and there is a peak value of ?? when n e ? 8 × 1019 m-1 for the ITER-like scenario. The influence of spectral broadening in parametric decay instabilities on the absorption coefficient is evaluated. The value of ?? with n ? being 2.5 is almost two times larger than that with n ? being 2.0 and is even lager in the case of 2.9, which will obviously increase the absorption of the LH power by alpha particles.

Wang, J.; Zhang, X.; Yu, L.; Zhao, X.



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.



Classification of shallow-water acoustic signals via alpha-Stable modeling of the one-dimensional wavelet coefficients  

E-print Network

Classification of shallow-water acoustic signals via alpha-Stable modeling of the one is presented for the classification of shallow water acoustic signals according to the environmental parameters simulated acoustic signals generated in a shallow water environment. © 2006 Acoustical Society of America

Tsakalides, Panagiotis


Ion selectivity of alpha-hemolysin with a beta-cyclodextrin adapter. I. Single ion potential of mean force and diffusion coefficient.  


The alpha-hemolysin (alphaHL) is a self-assembling exotoxin that binds to the membrane of a susceptible host cell and causes its death. Experimental studies show that electrically neutral beta-cyclodextrin (betaCD) can insert into the alphaHL channel and significantly increase its anion selectivity. To understand how betaCD can affect ion selectivity, molecular dynamics simulations and potential of mean force (PMF) calculations are carried out for different alphaHL channels with and without the betaCD adapter. A multiscale approach based on the generalized solvent boundary potential is used to reduce the size of the simulated system. The PMF profiles reveal that betaCD has no anion selectivity by itself but can increase the Cl(-) selectivity of the alphaHL channel when lodged into the pore lumen. Analysis shows that betaCD causes a partial desolvation of ions and affects the orientation of nearby charged residues. The ion selectivity appears to result from increased electrostatic interaction between the ion and the channel due to a reduction in dielectric shielding by the solvent. These observations suggest a reasonable explanation of the ion selectivity and provide important information for further ion channel modification. PMID:20041673

Luo, Yun; Egwolf, Bernhard; Walters, D Eric; Roux, Benoît



Determination of the 3He+alpha\\to 7Be asymp. normalization coefficients (nucl. vertex constants) and their application for extrapolation of the 3He(alpha,gamma)7Be astroph. S-factors to the solar energy region  

E-print Network

A new analysis of the precise experimental astrophysical $S$-factors for the direct capture $^3He(\\alpha,\\gamma)^7{\\rm {Be}}$ reaction [B.S. Nara Singh et al., Phys.Rev.Lett. {\\bf 93} (2004) 262503; D. Bemmerer et al., Phys.Rev.Lett. {\\bf 97} (2006) 122502; F.Confortola et al., Phys.Rev. {\\bf C 75} (2007) 065803 and T.A.D.Brown et al., Phys.Rev. {\\bf C 76} (2007) 055801] populating to the ground and first excited states of $^7{\\rm Be}$ is carried out based on the modified two - body potential approach in which the direct astrophysical $S$-factor, $S_{34}(E)$, is expressed in terms of the asymptotic normalization constants for $^3{\\rm {He}}+\\alpha\\to ^7{\\rm {Be}}$ and two additional conditions are involved to verify the peripheral character of the reaction under consideration. The Woods--Saxon potential form is used for the bound ($\\alpha+^3{\\rm {He}}$)- state and the $^3{\\rm {He}}\\alpha$- scattering wave functions. New estimates are obtained for the "indirectly measured", values of the asymptotic normalization constants (the nuclear vertex constants) for $^3{\\rm {He}}+\\alpha\\to^7{\\rm {Be}}(g.s.)$ and $^3{\\rm {He}}+\\alpha\\to^7{\\rm {Be}}(0.429 MeV)$ as well as the astrophysical $S$-factors $S_{34}(E)$ at E$\\le$ 90 keV, including $E$=0. The values of asymptotic normalization constants have been used for getting information about the $\\alpha$-particle spectroscopic factors for the mirror ($^7Li^7{\\rm {Be}}$)-pair.

S. B. Igamov; K. I. Tursunmakhatov; R. Yarmukhamedov



Confidence Interval Methods for Coefficient Alpha on the Basis of Discrete, Ordinal Response Items: Which One, If Any, Is the Best?  

ERIC Educational Resources Information Center

In this study, the authors aimed to examine 8 of the different methods for computing confidence intervals around alpha that have been proposed to determine which of these, if any, is the most accurate and precise. Monte Carlo methods were used to simulate samples under known and controlled population conditions wherein the underlying item…

Romano, Jeanine L.; Kromrey, Jeffrey D.; Owens, Corina M.; Scott, Heather M.



Determination of the 3He+alpha\\to 7Be asymp. normalization coefficients (nucl. vertex constants) and their application for extrapolation of the 3He(alpha,gamma)7Be astroph. S-factors to the solar energy region  

E-print Network

A new analysis of the modern precise measured astrophysical $S$ factors for the direct capture $^3He(\\alpha,\\gamma)^7{\\rm {Be}}$ reaction [B.S. Nara Singh {\\it et al.}, Phys.Rev.Lett. {\\bf 93}, 262503 (2004); D. Bemmerer {\\it et al.}, Phys.Rev.Lett. {\\bf 97}, 122502 (2006); F.Confortola {\\it et al.}, Phys.Rev.C {\\bf 75}, 065803 (2007), T.A.D.Brown {\\it et al.}, Phys.Rev. C {\\bf 76}, 055801 (2007) and A Di Leva, {\\it et al.},Phys.Rev.Lett. {\\bf 102}, 232502 (2009)] populating to the ground and first excited states of $^7{\\rm Be}$ is carried out based on the modified two - body potential approach. New estimates are obtained for the $^{\\glqq}$indirectly determined\\grqq\\, values of the asymptotic normalization constants (the nuclear vertex constants) for $^3{\\rm {He}}+\\alpha\\to{\\rm {^7Be}}$(g.s.) and $^3{\\rm {He}}+\\alpha\\to{\\rm {^7Be}}$(0.429 MeV) as well as the astrophysical $S$ factors $S_{34}(E)$ at E$\\le$ 90 keV, including $E$=0. The values of asymptotic normalization constants have been used for getting information about the $\\alpha$-particle spectroscopic factors for the mirror (${\\rm{^7Li}}{\\rm {^7Be}}$)-pair.

S. B. Igamov; Q. I. Tursunmahatov; R. Yarmukhamedov



Investigation of chemical bond characteristics, thermal expansion coefficients and bulk moduli of alpha-R2MoO6 and R2Mo2O7 (R = rare earths) by using a dielectric chemical bond method.  


Theoretical researches are performed on the alpha-R2MoO6 (R = Y, Gd, Tb Dy, Ho, Er, Tm and Yb) and pyrochlore-type R2Mo2O7 (R = Y, Nd, Sm, Gd, Tb and Dy) rare earth molybdates by using chemical bond theory of dielectric description. The chemical bonding characteristics and their relationship with thermal expansion property and compressibility are explored. The calculated values of linear thermal expansion coefficient (LTEC) and bulk modulus agree well with the available experimental values. The calculations reveal that the LTECs and the bulk moduli do have linear relationship with the ionic radii of the lanthanides: the LTEC decreases from 6.80 to 6.62 10(-6)/K and the bulk modulus increases from 141 to 154 GPa when R goes in the order Gd, Tb Dy, Ho, Er, Tm, and Yb in the alpha-R2MoO6 series; while in the R2Mo2O7 series, the LTEC ranges from 6.80 to 6.61 10(-6)/K and the bulk modulus ranges from 147 to 163 GPa when R varies in the order Nd, Sm, Gd, Tb and Dy. PMID:19115283

Li, Huaiyong; Zhang, Siyuan; Zhou, Shihong; Cao, Xueqiang



Simultaneous Optimization of Factor Assessibility and Representativeness: An Old Solution to a New Problem  

ERIC Educational Resources Information Center

The relationships among Rao's canonical factor analysis, Kaiser and Coffrey's alpha factor analysis, and Cronbach's alpha coefficient are discussed. Implications for test reliability and validity are noted. (JKS)

Greene, Vernon L.



Alpha Thalassemia  


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 ...


Relationships among Non-Academic Employee Perceptions of Manager Leadership Behaviors, Meaningful Work, and Selected Performance Drivers  

E-print Network

in an online survey. The survey was comprised of items from eight validated instruments with 45 items and additional demographic information. Respondents totaled 1,333 (31.5%). Data were analyzed using descriptive statistics, Cronbach’s alpha coefficient...

Hammons, Laura



Transport coefficients of gluonic fluid  

SciTech Connect

The shear ({eta}) and bulk ({zeta}) viscous coefficients have been evaluated for a gluonic fluid. The elastic, gg{yields}gg and the inelastic, number nonconserving, gg{yields}ggg processes have been considered as the dominant perturbative processes in evaluating the viscous coefficients to entropy density (s) ratios. Recently the processes: gg{yields}ggg has been revisited and a correction to the widely used Gunion-Bertsch (GB) formula has been obtained. The {eta} and {zeta} have been evaluated for gluonic fluid with the formula recently derived. At large {alpha}{sub s} the value of {eta}/s approaches its lower bound, {approx}1/4{pi}.

Das, Santosh K.; Alam, Jan-e [Variable Energy Cyclotron Centre, 1/AF, Bidhan Nagar, Kolkata-700064 (India)



Coefficient Estimates for Inverses of Starlike Functions of Positive Order  

Microsoft Academic Search

In the present paper, the coefficient estimates are found for the class $\\\\mathcal S^{*-1}(\\\\alpha)$ consisting of inverses of functions in the class of univalent starlike functions of order $\\\\alpha$ in $\\\\mathcal D=\\\\{z\\\\in\\\\mathbb C:|z|<1\\\\}$. These estimates extend the work of {\\\\it Krzyz, Libera and Zlotkiewicz [Ann. Univ. Marie Curie-Sklodowska, 33(1979), 103-109]} who found sharp estimates on only first two coefficients for

G. P. Kapoor; A. K. Mishra



Factor Scores, Structure Coefficients, and Communality Coefficients  

ERIC Educational Resources Information Center

This paper presents heuristic explanations of factor scores, structure coefficients, and communality coefficients. Common misconceptions regarding these topics are clarified. In addition, (a) the regression (b) Bartlett, (c) Anderson-Rubin, and (d) Thompson methods for calculating factor scores are reviewed. Syntax necessary to execute all four…

Goodwyn, Fara



Alpha-1 Antitrypsin Deficiency  


... Liver > Liver Disease Information > Alpha-1 Antitrypsin Deficiency Alpha-1 Antitrypsin Deficiency Explore this section to learn more about alpha-1 antitrypsin deficiency, including a description of the ...


ALPHA OMEGA ALPHA National Honor Medical Society  

E-print Network

12/6/2012 1 ALPHA OMEGA ALPHA National Honor Medical Society AA and Leadership The Alpha Omega Alpha honor medical society was organized in 1902 to "recognize and perpetuate Enter into a contract with patients and society Build a foundation of medical professionalism Define


Relations with phytoplankton distribution and spectral absorption coefficients in the equatorial Pacific  

NASA Astrophysics Data System (ADS)

Small size phytoplankton are dominated in the western and central equatorial Pacific. Our study of HPLC measurements, size fractions of chlorophyll (alpha) and flow cytometric measurements indicate that phytoplankton communities in the equatorial Pacific are dominated by prokaryotic picophytoplankton with Prochlorococcus and Synechococcus, and small size autotrophic eukaryotes. Phytoplankton populations and the distribution were showed to differ from oligotrophic warm water region of the western equatorial Pacific and mesotrophic upwelling region of the central equatorial Pacific. In the oligotrophic region, phytoplankton distribution forms maximum layer around the nitracline. Prochlorococcus is most abundant in there. In the mesotrophic region, chlorophyll maximum layer is not found clearly. The population of autotrophic eukaryotes represented as prymnesiophytes were increased in there. Specific spectral absorption coefficients of phytoplankton [(alpha) *ph((lambda) )] were measured throughout the euphotic zone in the two different regions. The (alpha) *ph((lambda) ) were also reconstructed from HPLC results as the total of specific spectral absorption coefficients of chlorophyll (alpha) [(alpha) *chla((lambda) )], chlorophyll b [(alpha) *chlb((lambda) )], chlorophyll c [(alpha) *chlc((lambda) )], photosynthetically active carotenoids [(alpha) *psc((lambda) )] and photoprotective carotenoids [(alpha) *ppc((lambda) )]. Reconstructed (alpha) *ph((lambda) ) were compared with measured (alpha) *ph((lambda) ). Reconstructed (alpha) *ph((lambda) ) were overestimated at the field of (alpha) *psc((lambda) ), especially in the mesotrophic region. The (alpha) *psc((lambda) ) were considered as high contribution of prymnesiophytes. It was assumed that the package effect of prymnesiophytes was a cause of the overestimate of reconstructed (alpha) *ph((lambda) ).

Matsumoto, Kazuhiko; Kawano, Takeshi; Okano, Hirofumi; Asanuma, Ichio



Acceptability of Weight Loss Treatments Among Overweight Adolescents and Their Caregivers  

E-print Network

but would be forced to categorize treatments differently by rank ordering them. Internal consistency reliability coefficients (Cronbach?s alpha) were calculated for the five scales (Gastric Banding Surgery, Weight Loss Pills, Dietary Therapy, Exercise... Therapy, Family Behavior Therapy) of the OTAQ. Overall, coefficient alphas demonstrated good to adequate internal consistency reliability across the parent and child versions of this measure. Alphas ranged from .79 to .87 on the parent-report version...

Rosnov, Danielle Leah



Alpha-1 Antitrypsin Deficiency  


... page from the NHLBI on Twitter. What Is Alpha-1 Antitrypsin Deficiency? Alpha-1 antitrypsin (an-tee-TRIP-sin) deficiency, or ... deficiency as it relates to lung disease. Overview Alpha-1 antitrypsin, also called AAT, is a protein ...


Liver and Alpha-1  


... Resources CSL Behring Grifols The mission of the Alpha-1 Foundation is to provide the leadership and ... more information, visit: The Alpha-1 Association is the leading national patient membership ...


Alpha One Foundation  


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 ...


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.



Zero-Coefficient Cuts  

NASA Astrophysics Data System (ADS)

Many cuts used in practice to solve mixed integer programs are derived from a basis of the linear relaxation. Every such cut is of the form ? T x ? 1, where x ? 0 is the vector of non-basic variables and ? ? 0. For a point bar{x} of the linear relaxation, we call ? T x ? 1 a zero-coefficient cut wrt. bar{x} if ?^T bar{x} = 0, since this implies ? j = 0 when bar{x}_j > 0. We consider the following problem: Given a point bar{x} of the linear relaxation, find a basis, and a zero-coefficient cut wrt. bar{x} derived from this basis, or provide a certificate that shows no such cut exists. We show that this problem can be solved in polynomial time. We also test the performance of zero-coefficient cuts on a number of test problems. For several instances zero-coefficient cuts provide a substantial strengthening of the linear relaxation.

Andersen, Kent; Weismantel, Robert


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)



Turbulent MHD transport coefficients - An attempt at self-consistency  

NASA Technical Reports Server (NTRS)

In this paper, some multiple scale perturbation calculations of turbulent MHD transport coefficients begun in earlier papers are first completed. These generalize 'alpha effect' calculations by treating the velocity field and magnetic field on the same footing. Then the problem of rendering such calculations self-consistent is addressed, generalizing an eddy-viscosity hypothesis similar to that of Heisenberg for the Navier-Stokes case. The method also borrows from Kraichnan's direct interaction approximation. The output is a set of integral equations relating the spectra and the turbulent transport coefficients. Previous 'alpha effect' and 'beta effect' coefficients emerge as limiting cases. A treatment of the inertial range can also be given, consistent with a -5/3 energy spectrum power law. In the Navier-Stokes limit, a value of 1.72 is extracted for the Kolmogorov constant. Further applications to MHD are possible.

Chen, H.; Montgomery, D.



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



Alpha-1 Antitrypsin Test  


... 1 Antitrypsin; ?1-antitrypsin Related tests: Protein Electrophoresis ; Total Protein ; Blood Gases ; Liver Panel At a Glance Test ... Alpha-1 antitrypsin measures the level of the protein AAT in blood. Alpha-1 antitrypsin ... antitrypsin genotype testing ( DNA testing) can ...


Emphysema and Alpha-1  


... 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. © 2015 American Association for Respiratory Care


Alpha-1 antitrypsin deficiency  


Alpha-1 antitrypsin (AAT) deficiency is a condition in which the body does not make enough of a protein ... Alpha-1 antitrypsin (AAT) is a type of protein called a protease inhibitor. AAT is made in the liver ...


Nonlinear interface dynamos with alpha -quenching  

NASA Astrophysics Data System (ADS)

There exist various mechanisms capable of limiting the magnitude of the (presumably) dynamo-generated, large-scale solar magnetic field. One such mechanism is the so-called ``alpha -quenching''. The underlying idea is that the Lorentz force associated with the dynamo-generated magnetic fields impedes the small scale, turbulent fluid motions giving rise to the so-called ``alpha -effect'' (the production of poloidal from toroidal fields in the framework of mean-field dynamo theory). In mean-field models, a popular ---yet essentially ad hoc--- prescription for alpha -quenching consists in replacing the coefficient (alpha ) of the alpha -effect source term in the dynamo equations by an expression of the form alpha -> alpha (B) =alpha_0 /(1+(|B|/B_eq)(2)) , where alpha_0 is a measure of the strength of the alpha -effect in the linear regime, and B_eq is the equipartition field strength, based on the kinetic energy of the turbulent, convective fluid motions (B_eq ~ 10(4) G at the base of the solar convection zone). In principle, such ``Weak Quenching'' allows the production of magnetic fields of roughly equipartition strength, as demonstrated by the numerous conventional mean-field dynamo models making use of eq. (1), or some close variant, published to date. Vainshtein & Cattaneo (1992, ApJ 393, 165) and Gruzinov & Diamond (1995, Phys. Plasmas 2, 1941) have argued, however, that alpha -quenching should be described by alpha -> alpha (B) =alpha_0 /(R_m(|B|/B_eq)(2)) where R_m is a magnetic Reynolds number based on the microscopic properties of the flow (R_m>> 1 for solar interior conditions). This now describes a much stronger form of alpha -quenching, and, with R_m>> 1, could be fatal to large-scale dynamo action, in the sense that the dynamo could only produce magnetic fields of strength << B_eq. This is in marked contradiction with the demands set by recent models of bipolar magnetic region emergence, which require field strengths of order 10x B_eq ~ 10(5) G for the observed latitudes and tilt of emergence to be adequately reproduced. In this contribution, we investigate the circumstances under which interface dynamos can avoid alpha -quenching, either in the ``Weak'' or ``Strong'' forms defined above. In interface dynamos the alpha -effect is assumed to operate within the solar convective envelope, while the strongest magnetic fields are generated by shearing below the core-envelope interface (Parker 1993, ApJ 408, 707; Charbonneau & MacGregor, submitted to ApJ). This spatial segregation of the alpha -effect source region is the key to avoiding alpha -quenching. This is illustrated using a few nonlinear, kinematic interface dynamo solutions applicable to the Sun.

Charbonneau, P.; MacGregor, K. B.



Separation and determination of denatured alpha(s1)-, alpha(s2)-, beta- and kappa-caseins by hydrophobic interaction chromatography in cows', ewes' and goats' milk, milk mixtures and cheeses.  


Caseins alpha(s1)-, alpha(s2)-, beta- and kappa- from raw cows', ewes' and goats' milk were separated and determined by hydrophobic interaction chromatography (HIC) by using a Propyl column (Eichrom) in the presence of 8.0 M urea in the mobile phase. The method is based on fast and easy solubilization of real raw samples by 4.0 M guanidine thiocyanate followed by the HIC analysis, without any preliminary precipitation or separation of the casein fraction. Elution conditions have been optimized by analyzing commercial single bovine standard caseins and their mixture. In the optimized chromatographic conditions the four casein fractions were separated in less than 45 min. A linear relationship between the concentration of casein and peak area (UV absorbance detector at 280 nm) has been obtained over the concentration range of 0.5 to 40 microM. The detection limit for alpha-, beta- and kappa-caseins ranged between 0.35 and 0.70 microM. The precision of the method was evaluated, the coefficient of variation for alpha-, beta- and kappa-casein determination ranging between 3.0 and 6.0%. The method has been validated by the analysis of reference skim milk powder (BCR-063R) certificated for total nitrogen content. The method was applied to commercial casein mixture and to the qualitative and quantitative analysis of casein fractions in unprocessed, raw cows', goats' and ewes' milk (10 samples analyzed for each species), in one sample of unprocessed buffalos' milk and in commercial cheeses (mozzarella, robiola, ricotta and stracchino). Binary mixtures of milk (cow/goat and cow/ewe) were also analyzed and the ratio between casein peak areas (alpha(s1)/kappa, alpha(s2)/beta, beta/kappa and alpha(s2)/alpha(s1)) of the HIC chromatograms was proposed and discussed in order to evaluate a possible application of this method to detect milk adulteration. PMID:12779219

Bramanti, Emilia; Sortino, Chandra; Onor, Massimo; Beni, Francesca; Raspi, Giorgio



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. PMID:23406896

Shah, Dhaval K.; Betts, Alison M.



Rossi Alpha Method  

SciTech Connect

The Rossi Alpha Method has proved to be valuable for the determination of prompt neutron lifetimes in fissile assemblies having known reproduction numbers at or near delayed critical. This workshop report emphasizes the pioneering applications of the method by Dr. John D. Orndoff to fast-neutron critical assemblies at Los Alamos. The value of the method appears to disappear for subcritical systems where the Rossi-..alpha.. is no longer an ..alpha..-eigenvalue.

Hansen, G.E.



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



Isospin symmetry in mirror {alpha} decays  

SciTech Connect

We show that a consequence of isospin symmetry, recently discovered in mirror conjugated one-nucleon decays, can be extended to mirror-conjugated {alpha}-particle decays, both virtual and real. For virtual {alpha} decays of bound mirror pairs this symmetry manifests itself as a relation between the asymptotic normalization coefficients (ANCs) of {alpha}-particle overlap integrals. This relation is given by a simple analytical formula that involves {alpha}-particle separation energies and charges of residual nuclei. For bound-unbound mirror pairs, the ANC of a bound nucleus is related to the {alpha} width of the mirror unbound level. For unbound mirror pairs we get a new analytical formula that relates the widths of mirror resonances. We test the validity of these analytical formulas against the predictions of a two-body potential and of a many-body microscopic cluster model for several mirror states in {sup 7}Li-{sup 7}Be, {sup 11}B-{sup 11}C, and {sup 19}F-{sup 19}Ne isotopes. We show that these analytical formulas are valid in many cases but that some deviations can be expected for isotopes with strongly deformed and easily excited cores. In general, the results from microscopic model are not very sensitive to model assumptions and can be used to predict unknown astrophysically relevant cross sections using known information about mirror systems.

Timofeyuk, N. K.; Johnson, R. C. [Department of Physics, School of Electronics and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Descouvemont, P. [Physique Nucleaire Theorique et Physique Mathematique, CP229 Universite Libre de Bruxelles, B-1050 Brussels (Belgium)



Alpha-1 Health Tips  


... risk factors. The biggest risk factor for lung disease is cigarette smoking. Any Alpha who smokes must stop! It is also important to avoid second-hand smoke and avoid inhaling irritants at ... available for Alphas with lung disease, this is only one part of the management ...


Alpha-1 Panniculitis  


... of serum levels of alpha-1 antitrypsin (typically PI*ZZ) and others with only mild deficiency (typically PI*MZ). In one reported series of 26 patients with panniculitis and Alpha-1, 62 percent were PI*ZZ; 15 percent were PI*MZ; 8 percent ...


Semiparametric Estimation of Index Coefficients  

Microsoft Academic Search

This paper gives a solution to the problem of estimating coefficients of index models, through the estimation of the density-weighted average derivative of a general regression function. A normalized version of the density-weighted average derivative can be estimated by certain linear instrumental variables coefficients. The estimators, based on sample analogies of the product moment representation of the average derivative, are

James L. Powell; James H. Stock; Thomas M. Stoker



Study of DCT coefficient distributions  

Microsoft Academic Search

Many image and video compression schemes perform the discrete cosine transform (DCT) to represent image data in frequency space. An analysis of a broad suite of images confirms previous finding that a Laplacian distribution can be used to model the luminance AC coefficients. This model is expanded and applied to color space (Cr\\/Cb) coefficients. In MPEG, the DCT is used

Stephen Smoot



Event counting alpha detector  


An electrostatic detector is disclosed for atmospheric radon or other weak sources of alpha radiation. In one embodiment, nested enclosures are insulated from one another, open at the top, and have a high voltage pin inside and insulated from the inside enclosure. An electric field is produced between the pin and the inside enclosure. Air ions produced by collision with alpha particles inside the decay volume defined by the inside enclosure are attracted to the pin and the inner enclosure. With low alpha concentrations, individual alpha events can be measured to indicate the presence of radon or other alpha radiation. In another embodiment, an electrical field is produced between parallel plates which are insulated from a single decay cavity enclosure. 6 figs.

Bolton, R.D.; MacArthur, D.W.



Event counting alpha detector  


An electrostatic detector for atmospheric radon or other weak sources of alpha radiation. In one embodiment, nested enclosures are insulated from one another, open at the top, and have a high voltage pin inside and insulated from the inside enclosure. An electric field is produced between the pin and the inside enclosure. Air ions produced by collision with alpha particles inside the decay volume defined by the inside enclosure are attracted to the pin and the inner enclosure. With low alpha concentrations, individual alpha events can be measured to indicate the presence of radon or other alpha radiation. In another embodiment, an electrical field is produced between parallel plates which are insulated from a single decay cavity enclosure.

Bolton, Richard D. (Los Alamos, NM); MacArthur, Duncan W. (Los Alamos, NM)



Imaging alpha particle detector  


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)



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)



Genetics Home Reference: Alpha thalassemia  


... PubMed Recent literature OMIM Genetic disorder catalog Conditions > Alpha thalassemia On this page: Description Genetic changes Inheritance ... names Glossary definitions Reviewed August 2009 What is alpha thalassemia? Alpha thalassemia is a blood disorder that ...


Critical analysis of the extinction coefficient of chloroplast cytochrome f.  


In oxygenic photosynthesis the cytochrome bf complex links electron transport between photosystem II and photosystem I. The largest subunit of the complex is cytochrome f, a 32-kDa polypeptide that is anchored in the membrane by a transmembrane alpha helix located near the carboxyl end. The three-dimensional structure of the soluble domain of cytochrome f isolated from turnip has been determined by X-ray crystallography to 1.96 A resolution. The structure revealed several novel features compared to previously solved soluble c-type cytochrome structures, including a predominant beta-strand motif, the N-terminal alpha-amino group of a tyrosyl residue as an orthogonal ligand, and a bound internal water chain. Here we report a novel and unprecedented extinction coefficient for cytochrome f. Using the pyridine hemochrome assay, the reduced minus oxidized extinction coefficient for the soluble domain of turnip cytochrome f was 26 +/- 1 mM-1 cm-1 for the alpha-band wavelength peak at 554 nm relative to the isosbestic wavelengths (534, 543.5 and 560.5 nm), and 25 +/- 1 mM-1 cm-1 for spinach cytochrome f relative to the isosbestic wavelengths (533.5, 543.3 and 560.2). The extinction coefficients reported here are significantly higher than previously published values for cytochrome f. We believe earlier determinations underestimated the cytochrome f extinction coefficient and that the same is likely true for commonly used extinction coefficients of cytochrome b6. The cytochrome f extinction coefficient is large compared to most other c-type cytochromes, which could be due to the unique axial ligand of the cytochrome f heme. Polarographic measurements show the midpoint potential of soluble turnip cytochrome f to be 362 +/- 5 mV at pH 7.5. The midpoint potential was pH-independent from 5.0 to 8.5, and pH-dependent from pH 8.5 to 10.5 (-58 mV/pH unit) with a pK on the oxidized from near 9. Storage of some samples of purified turnip and spinach cytochrome f at -20 degrees C modified the heme environment in a fraction of the protein, shifting the midpoint potential to near -165 mV (pH 7.5) and the peak of the alpha-band absorption spectrum from 554 nm to 552 nm. PMID:9131046

Metzger, S U; Cramer, W A; Whitmarsh, J



Alpha Thalassemia (For Parents)  


... of alpha thalassemia trait may want to seek genetic counseling if they're considering having children. If your ... For Parents MORE ON THIS TOPIC Genetic Testing Genetic Counseling All About Genetics Blood Blood Test: Hemoglobin Electrophoresis ...


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.



Converting Sabine absorption coefficients to random incidence absorption coefficients.  


Absorption coefficients measured by the chamber method are referred to as Sabine absorption coefficients, which sometimes exceed unity due to the finite size of a sample and non-uniform intensity in the reverberation chambers under test. In this study, conversion methods from Sabine absorption coefficients to random incidence absorption coefficients are proposed. The overestimations of the Sabine absorption coefficient are investigated theoretically based on Miki's model for porous absorbers backed by a rigid wall or an air cavity, resulting in conversion factors. Additionally, three optimizations are suggested: An optimization method for the surface impedances for locally reacting absorbers, the flow resistivity for extendedly reacting absorbers, and the flow resistance for fabrics. With four porous type absorbers, the conversion methods are validated. For absorbers backed by a rigid wall, the surface impedance optimization produces the best results, while the flow resistivity optimization also yields reasonable results. The flow resistivity and flow resistance optimization for extendedly reacting absorbers are also found to be successful. However, the theoretical conversion factors based on Miki's model do not guarantee reliable estimations, particularly at frequencies below 250 Hz and beyond 2500?Hz. PMID:23742349

Jeong, Cheol-Ho



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



Superfluid Mutual-friction Coefficients from Vortex Dynamics in the Two-dimensional Galerkin-truncated Gross-Pitaevskii Equation  

E-print Network

We present algorithms for the ab-initio determination of the temperature ($T$) dependence of the mutual-friction coefficients $\\alpha$ and $\\alpha'$ and the normal-fluid density $\\rho_{\\rm n}$ in the two-dimensional (2D) Galerkin-truncated Gross-Pitaevskii system. Our algorithms enable us to determine $\\alpha(T)$, even though fluctuations in 2D are considerably larger than they are in 3D. We also examine the implications of our measurements of $\\alpha'(T)$ for the Iordanskii force, whose existence is often questioned.

Vishwanath Shukla; Marc Brachet; Rahul Pandit



Superfluid Mutual-friction Coefficients from Vortex Dynamics in the Two-dimensional Galerkin-truncated Gross-Pitaevskii Equation  

E-print Network

We present algorithms for the ab-initio determination of the temperature ($T$) dependence of the mutual-friction coefficients $\\alpha$ and $\\alpha'$ and the normal-fluid density $\\rho_{\\rm n}$ in the two-dimensional (2D) Galerkin-truncated Gross-Pitaevskii system. Our algorithms enable us to determine $\\alpha(T)$, even though fluctuations in 2D are considerably larger than they are in 3D. We also examine the implications of our measurements of $\\alpha'(T)$ for the Iordanskii force, whose existence is often questioned.

Shukla, Vishwanath; Pandit, Rahul



Seebeck coefficient of one electron  

SciTech Connect

The Seebeck coefficient of one electron, driven thermally into a semiconductor single-electron box, is investigated theoretically. With a finite temperature difference ?T between the source and charging island, a single electron can charge the island in equilibrium, directly generating a Seebeck effect. Seebeck coefficients for small and finite ?T are calculated and a thermally driven Coulomb staircase is predicted. Single-electron Seebeck oscillations occur with increasing ?T, as one electron at a time charges the box. A method is proposed for experimental verification of these effects.

Durrani, Zahid A. K., E-mail: [Department of Electrical and Electronic Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom)




NSDL National Science Digital Library

AlphaGalileo is designed for science journalists, but anyone with an itch for breaking academic news will enjoy this research-rich site. Readers may browse by region, including Africa, Asia, Caribbean, Europe, Latin America, Middle East, North America, Oceania, and this Scout EditorâÂÂs favorite: Extraterrestrial. Next, try trawling the site by Science, Health, Society, Humanities, Arts, Applied Science, and Business for the latest illuminating research in each of these fields. AlphaGalileo also issues News Releases, usually five or six paragraphs long, that cover particularly interesting research findings. Best of all, since the Scout Report previously covered AlphaGalileo back in 2007, the site has dropped its membership requirements and visitors can browse more freely than ever.


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.



Tables of the coefficients A  

NASA Technical Reports Server (NTRS)

Numerical coefficients required to express the angular distribution for the rotationally elastic or inelastic scattering of electrons from a diatomic molecule were tabulated for the case of nitrogen and in the energy range from 0.20 eV to 10.0 eV. Five different rotational states are considered.

Chandra, N.



Transport Coefficients of Quantum Plasma  

Microsoft Academic Search

The two time Green function method is applied to calculate the transport coefficients of an elecron gas. The sequence of equations for the Green functions is derived, and it is shown that the results corresponding to the random phase approximation (including the exchange effects) can be obtained by terminating this sequence at the first stage. Proceeding to the second stage,

Mitsuo Watabe



Sublimation Coefficient of Water Ice  

NASA Astrophysics Data System (ADS)

In simulations of evolution of cometary nuclei it is commonly assumed that the coefficients of sublimation and condensation of the volatiles are both equal to one. However, the laboratory investigation of water ice samples under cometary-like conditions (Kossacki et al., 1997) suggests, that the sublimation flux calculated with the Hertz-Knudsen formula and the above assumption is nearly an order of magnitude too high. A similar conclusion can be drawn from the results of various experiments on growth from vapour phase and sublimation of ice crystals (Lamb and Scott, 1972; Beckmann and Lacmann, 1982; Sei and Gonda, 1989). These results imply that the sublimation coefficient can be as low as 0.1. The above coefficients depend on various parameters such as temperature, concentration of surface impurities as well as deviation of the vapour pressure from that of the phase equilibrium. In this work we discuss the temperature dependence of both of these coefficients. We also propose an empirical formula to fit the temperature dependence. This new formulation is also used to analyse the implications for the thermal conductivity of a porous cometary-like ice.

Kossacki, K. J.; Markiewicz, W. J.; Skorov, Y.; Koemle, N. I.



Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny  

E-print Network

Absorbed dose in target cell nuclei and dose conversion coefficient of radon progeny in the human Abstract To calculate the absorbed dose in the human lung due to inhaled radon progeny, ICRP focussed and secretory cells). The absorbed energy for alpha particles emitted by radon progeny in the human respiratory

Yu, K.N.


Light scattering studies on alpha-crystallin from bovine eye lens.  


Using the usual angular light scattering technique, we have measured the concentration dependence of reduced scattering intensity of fractionated bovine lens alpha-crystallin (alpha A-chain) in the presence of 30 mM calcium chloride and 0.1 M sodium chloride. The inverse intensity of scattered light at zero angle per unit concentration of alpha-crystallin has a significant upward curvature with increasing alpha-crystallin concentration. The third virial coefficient determined from this upward curvature was 1.24 x 10(-3) (mol 1/2 ml 1/2 g-1). PMID:7358624

Sano, Y



[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.



[alpha-Neurotoxins and alpha-conotoxins--nicotinic cholinoreceptor blockers].  


The review is devoted to the competitive blockers of different nicotinic acetylcholine receptors, alpha-neurotoxins from snake venoms, and alpha-conotoxins from marine snails of the Conidae family. The relationship between the structure and function of these toxins is discussed. Recent data on the mechanism of alpha-neurotoxin and alpha-conotoxin interaction with the nicotinic acetylcholine receptor are presented. PMID:10645484

Utkin, Iu N; Kasheverov, I E; Tsetlin, V I




Microsoft Academic Search

The influence of alpha -alanine on the distribution coefficient in TBP-; aqueous nitrate extraction of Zr was investigated. It was found that 0.1 M ; alanine had no influence on the distribution. (R.V.J.);

A. S. Solovkin; Z. N. Tsvetkova; N. S. Povitskii



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.



Coefficient systems and Jacquet modules.  

E-print Network

Let F be a locally compact non-archimedean field and G the group of F-rational points of an algebraic group assumed to be defined over F, semisimple, simply connected and of F-rank 1. Let pi be a complex irreducible supercuspidal representation of G. We prove that pi is "nearly" induced in the following sense. There exist a maximal compact subgroup K of G and an irreducible smooth representation lamba of K such that pi contains lambda by restriction to K and such that the representation compactly induced from lambda to G is a finite direct sum of irreducible supercuspidal representations. The proof relies on the Schneider and Stuhler theory of equivariant coefficient systems and on a lemma on coefficient systems and Jacquet modules.

Paul Broussous


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.



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)



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 propertymeasurement for evaluating the potential performance of novel thermoelectricmaterials. 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, thermoelectricmeasurements 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.; Tritt, T.; Uher, Ctirad



Factoring polynomials with rational coefficients  

Microsoft Academic Search

In this paper we present a polynomial-time algorithm to solve the following problem: given a non-zero polynomial fe Q(X) in one variable with rational coefficients, find the decomposition of f into irreducible factors in Q(X). It is well known that this is equivalent to factoring primitive polynomials feZ(X) into irreducible factors in Z(X). Here we call f~ Z(X) primitive if

A. K. Lenstra; H. W. Lenstra; L. Lovfiasz



Ethanol inhibits palmitoylation of G protein G alpha(s).  


Neurobiological actions of ethanol have been linked to perturbations in cyclic AMP (cAMP)-dependent signaling processes. Chronic ethanol exposure leads to desensitization of cAMP production in response to physiological ligands (heterologous desensitization). Ethanol-induced alterations in neuronal expression of G proteins G(s) and G(i) have been invoked as a cause of heterologous desensitization. However, effects of ethanol on G protein expression vary considerably among different experimental protocols, various brain regions and diverse neuronal cell types. Dynamic palmitoylation of G protein alpha subunits is critical for membrane localization and protein-protein interactions, and represents a regulatory feature of G protein function. We studied the effect of ethanol on G alpha(s) palmitoylation. In NG108-15 rat neuroblastoma x glioma hybrid cells, acute exposure to pharmacologically relevant concentrations of ethanol (25-100 mm) inhibited basal and prostaglandin E1-stimulated incorporation of palmitate into G alpha(s). Exposure of NG108-15 cells to ethanol for 72 h induced a shift in G alpha(s) to its non-palmitoylated state, coincident with an inhibition of prostaglandin E1-induced cAMP production. Both parameters were restored following 24 h of ethanol withdrawal. Chronic ethanol exposure also induced the depalmitoylation of G alpha(s) in human embryonic kidney (HEK)293 cells that overexpress wild-type G alpha(s) and caused heterologous desensitization of adenylyl cyclase. By contrast, HEK293 cells that express a non-palmitoylated mutant of G alpha(s) were insensitive to heterologous desensitization after chronic ethanol exposure. In summary, the findings identify a novel effect of ethanol on post-translational lipid modification of G alpha(s), and represent a mechanism by which ethanol might affect adenylyl cyclase activity. PMID:15140191

Hallak, Hazem; Rubin, Raphael



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



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



Study of backscattering in alpha-particle sources with the new code AlfaMC  

NASA Astrophysics Data System (ADS)

The activity of alpha-particle sources with negligible thickness can be absolutely determined using 2? counting geometry detectors, requiring corrections for backscattering from the source backing. The experimental determination of these corrections is subject to large uncertainties, because the contribution of the backscattered alpha particles to the total counting is generally very low. An interesting alternative is then to use Monte Carlo methods which simulate the transport of alpha-particles into the source. The programme AlfaMC, a new Monte Carlo code developed to simulate specifically the transport of alpha particles, was here applied to the study of the backscattering in alpha-particle sources. Energy and angular distributions for the backscattered alpha particles were deeply analysed based on a multiple scattering process, as a result of a large number of weak collisions with atomic electrons. Some calculated values for the backscattering coefficient were compared with experimental values, showing a good agreement.

Vargas, M. Jurado; Timón, A. Fernández



A model for the disc Lyman alpha emission of Uranus  

SciTech Connect

A new efficient radiative transfer algorithm for inhomogeneous atmospheres has been used to simulate the limb to limb Lyman {alpha} reflectivities observed with the Voyager ultraviolet spectrometer during the flyby of Uranus. It was shown that complete frequency redistribution should be adequate to describe the disc emissions. The model atmosphere used was derived using a combination of Voyager measurements and modeling. Atomic H densities calculated had sources derivable directly from solar FUV and EUV fluxes. To fit the observations, four contributions are evaluated: (1) the resonance scattering of solar Lyman {alpha} radiation, (2) Rayleigh-Raman scattering of solar Lyman {alpha} radiation, (3) the resonance scattering of interplanetary Lyman {alpha} radiation, and (4) a possible internal source of unknown origin. From comparison with the observations, and provided that the published Voyager calibrations are correct, it is shown that only atmospheres with low eddy diffusion coefficients (K{sub H}{le}100 cm{sup 2} s{sup {minus}1}) and an internal source could simulate both the shape and the strength of the measured disc emission. The main results are then that the direct solar Lyman {alpha} scattering contribution (type 1 plus type 2) is of the order of 760 R, the scattering of interplanetary Lyman {alpha} contributes about 320 R, and a small additional internal source providing about 100-500 R is needed to match the measurements. Further, the analysis of the disc intensities suggests that there is no strong variation of K with latitude.

Jaffel, L.B.; Vidal-Madjar, A. (Centre National de la Recherche Scientifique, Paris (France)); Prange, R.; Emerich, C. (Inst. d'Astrophysique Spatiale, Verrieres le Buisson (France)); McConnell, J.C. (York Univ., North York, Ontario (Canada))



Radiation Pressure in Lyman-alpha Forest Clouds  

E-print Network

The effective recombination coefficient, alpha_eff, is refined for optically thin cases. Radiation pressure in Lyman-alpha and HeII Lyman-alpha is calculated in terms of the number density and the mean free path. Pressure equilibrium between Lyman-alpha clouds and an adiabatically expanding inter-galactic medium is assumed, n_i T_i = n_c T_c. Numerical models of isothermal and adiabatic expanding Lyman-alpha forest clouds are presented, including evolving UV sources (QSOs), with various turn-on times z_on = 20, 10, and 5, and with q_0 = 1/2 in a matter-dominated Friedmann-Robertson-Walker Universe. These models lead to the conclusion that the radiation pressure and QSO turn-on time are significant in determining the range of physical size, D, and neutral hydrogen column density, N(HI), permitted for stable Lyman-alpha forest clouds. This manuscript was written in 1989 and never submitted for publication.

Michael Fisher



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



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



Water transport by the bacterial channel alpha-hemolysin  

NASA Technical Reports Server (NTRS)

This study is an investigation of the ability of the bacterial channel alpha-hemolysin to facilitate water permeation across biological membranes. alpha-Hemolysin channels were incorporated into rabbit erythrocyte ghosts at varying concentrations, and water permeation was induced by mixing the ghosts with hypertonic sucrose solutions. The resulting volume decrease of the ghosts was followed by time-resolved optical absorption at pH 5, 6, and 7. The average single-channel permeability coefficient of alpha-hemolysin for water ranged between 1.3x10-12 cm/s and 1.5x10-12 cm/s, depending on pH. The slightly increased single-channel permeability coefficient at lower pH-values was attributed to an increase in the effective pore size. The activation energy of water transport through the channel was low (Ea=5.4 kcal/mol), suggesting that the properties of water inside the alpha-hemolysin channel resemble those of bulk water. This conclusion was supported by calculations based on macroscopic hydrodynamic laws of laminar water flow. Using the known three-dimensional structure of the channel, the calculations accurately predicted the rate of water flow through the channel. The latter finding also indicated that water permeation data can provide a good estimate of the pore size for large channels.

Paula, S.; Akeson, M.; Deamer, D.



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.



Native folding of an acetylcholine receptor alpha subunit expressed in the absence of other receptor subunits.  


An alpha subunit cDNA of the mouse nicotinic acetylcholine receptor under transcriptional control of the Rous Sarcoma virus long terminal repeat was transfected into and expressed in a quail fibroblast cell line. The biosynthesis and post-translational modification of the alpha subunit protein made in this heterologous system have been studied using immunoprecipitation and ligand binding assays. The polypeptide is present at high steady-state levels and inserted in the correct transmembrane orientation. However, in the absence of assembly with other subunits the alpha subunit is confined to an intracellular membrane compartment and is not transported to the plasma membrane. Twenty percent of the newly synthesized alpha subunit acquired high affinity alpha bungarotoxin binding in a time-dependent process within 20 min of translation. Sucrose gradient fractionation demonstrated that both the polypeptide and toxin binding forms of the alpha subunit have a sedimentation coefficient of 5 s suggesting the absence of stable homo-oligomers. Quantitative binding assays demonstrated that the apparent affinity and rate of association of alpha bungarotoxin to the unassembled alpha subunit are greater than for native receptor. On the other hand, the affinities for the small ligands D-tubocurarine and gallamine are 10(3) lower than for native receptor; no detectable binding was observed for decamethonium, hexamethonium, or carbamylcholine. Thus, the acetylcholine receptor alpha subunit, independent of other subunits of the receptor, acquires a mature conformation and high affinity alpha bungarotoxin binding when expressed in a quail fibroblast cell line. PMID:2826454

Blount, P; Merlie, J P



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 (200 A - 6000 A). The results are compared to theory and other measurements. The absorption coefficient for the same wavelength interval is also given.

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



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.



Creating materials with a desired refraction coefficient  

E-print Network

A method is given for creating material with a desired refraction coefficient. The method consists of embedding into a material with known refraction coefficient many small particles of size $a$. The number of particles per unit volume around any point is prescribed, the distance between neighboring particles is $O(a^{\\frac{2-\\kappa}{3}})$ as $a\\to 0$, $0refraction coefficient is the coefficient $n^2(x)$ in the wave equation $[\

A. G. Ramm



Background canceling surface alpha detector  


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.

MacArthur, Duncan W. (Los Alamos, NM); Allander, Krag S. (Ojo Caliente, NM); Bounds, John A. (Los Alamos, NM)



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.



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.



Thermal-Expansion Coefficient and Universality near the Superfluid Transition of 4He under Pressure  

Microsoft Academic Search

High-resolution measurements of the thermal-expansion coefficient of pressurized 4He (5 bar<=P<=29 bar) near Tlambda (2×10-5<~|t|<~0.07 t?TTlambda-1) by a new technique yielded a universal (pressure-independent) critical exponent alpha=alpha'=-0.026+\\/-0.004, a universal amplitude ratio AA'=1.11+\\/-0.02 for the leading singularity, and a universal ratio DD'=1.27+\\/-0.2 for the amplitudes of the confluent singularity. These results agree with renormalization-group theory, but are in part contrary to

K. H. Mueller; F. Pobell; Guenter Ahlers



Long range alpha particle detector  


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.



Long range alpha particle detector  


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)



Alpha particle confinement in tokamaks  

SciTech Connect

An assessment of diffusive tokamak transport mechanisms of concern for alpha particles indicates that the ''stochastic regime'' is the only one which appears to pose a real danger for adequate alpha confinement. This fact, in conjunction with the threshold character of that mechanism, allows one to decide whether an alpha born at a given location will be lost or confined, according to a very simple criterion. Implementing this criterion numerically results in a new code for the assessment of alpha confinement, which is orders of magnitude faster than earlier codes used for this purpose. 13 refs., 3 figs., 1 tab.

White, R.B.; Mynick, H.E.



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.



Gross alpha analytical modifications that improve wastewater treatment compliance  

SciTech Connect

This paper will propose an improvement to the gross alpha measurement that will provide more accurate gross alpha determinations and thus allow for more efficient and cost-effective treatment of site wastewaters. To evaluate the influence of salts that may be present in wastewater samples from a potentially broad range of environmental conditions, two types of efficiency curves were developed, each using a thorium-230 (Th-230) standard spike. Two different aqueous salt solutions were evaluated, one using sodium chloride, and one using salts from tap water drawn from the Bergen County, New Jersey Publicly Owned Treatment Works (POTW). For each curve, 13 to 17 solutions were prepared, each with the same concentration of Th-230 spike, but differing in the total amount of salt in the range of 0 to 100 mg. The attenuation coefficients were evaluated for the two salt types by plotting the natural log of the counted efficiencies vs. the weight of the sample's dried residue retained on the planchet. The results show that the range of the slopes for each of the attenuation curves varied by approximately a factor of 2.5. In order to better ensure the accuracy of results, and thus verify compliance with the gross alpha wastewater effluent criterion, projects depending on gross alpha measurements of environmental waters and wastewaters should employ gross alpha efficiency curves prepared with salts that mimic, as closely as possible, the salt content of the aqueous environmental matrix. (authors)

Tucker, B.J. [Shaw Environmental and Infrastructure, Salem, NH (United States); Arndt, S. [Safety and Ecology Corporation, Maywood, NJ (United States)



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.



Live! From 2-Alpha  

NSDL National Science Digital Library

This activity is one of several in which students are required to access and analyze actual data from NASA missions, including video "interviews" with real NASA scientists, to solve a mystery. In this mystery, students learn about the force of gravity and how scientists analyze data by studying the properties of different objects in space. Live! From 2-Alpha can be used to support instruction about forces and motion, origin and evolution of the universe, and the interaction of energy and matter. This activity is one of several in "Space Mysteries," a series of inquiry-driven, interactive Web explorations. Each Mystery in "Space Mysteries" is designed to teach at least one physical science concept (e.g. interactions of energy and matter, structures and properties of matter, energy, motion, or forces), and is accompanied by materials to be used by classroom teachers.



Technology Transfer Automated Retrieval System (TEKTRAN)

Recent DFT optimization studies on alpha-maltose improved our understanding of the preferred conformations of alpha-maltose and the present study extends these studies to alpha-maltotriose with three alpha-D-glucopyranose residues linked by two alpha-[1-4] bridges, denoted herein as DP-3's. Combina...


Alpha particle emitters in medicine  

SciTech Connect

Radiation-induced cancer of bone, liver and lung has been a prominent harmful side-effect of medical applications of alpha emitters. In recent years, however, the potential use of antibodies labeled with alpha emitting radionuclides against cancer has seemed promising because alpha particles are highly effective in cell killing. High dose rates at high LET, effectiveness under hypoxic conditions, and minimal expectancy of repair are additional advantages of alpha emitters over antibodies labeled with beta emitting radionuclides for cancer therapy. Cyclotron-produced astatine-211 ({sup 211}At) and natural bismuth-212 ({sup 212}Bi) have been proposed and are under extensive study in the United States and Europe. Radium-223 ({sup 223}Ra) also has favorable properties as a potential alpha emitting label, including a short-lived daughter chain with four alpha emissions. The radiation dosimetry of internal alpha emitters is complex due to nonuniformly distributed sources, short particle tracks, and high relative specific ionization. The variations in dose at the cellular level may be extreme. Alpha-particle radiation dosimetry, therefore, must involve analysis of statistical energy deposition probabilities for cellular level targets. It must also account fully for nonuniform distributions of sources in tissues, source-target geometries, and particle-track physics. 18 refs., 4 figs.

Fisher, D.R.



EEG Alpha Power and Intelligence.  

ERIC Educational Resources Information Center

Tested whether alpha power in different sub-bands is selectively related to intelligence. For 74 Austrian subjects, the EEG was recorded during a resting session and 2 different intelligence tests were performed. Findings show a strong positive correlation between intelligence and alpha power. (SLD)

Doppelmayr, M.; Klimesch, W.; Stadler, W.; Pollhuber, D.; Heine, C.



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.



The Drosophila acetylcholine receptor subunit D alpha5 is part of an alpha-bungarotoxin binding acetylcholine receptor.  


The central nervous system of Drosophila melanogaster contains an alpha-bungarotoxin-binding protein with the properties expected of a nicotinic acetylcholine receptor. This protein was purified 5800-fold from membranes prepared from Drosophila heads. The protein was solubilized with 1% Triton X-100 and 0.5 M sodium chloride and then purified using an alpha-cobratoxin column followed by a lentil lectin affinity column. The purified protein had a specific activity of 3.9 micromol of 125I-alpha-bungarotoxin binding sites/g of protein. The subunit composition of the purified receptor was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. This subunit profile was identical with that revealed by in situ labeling of the membrane-bound protein using the photolyzable methyl-4-azidobenzoimidate derivative of 125I-alpha-bungarotoxin. The purified receptor reveals two different protein bands with molecular masses of 42 and 57 kDa. From sedimentation analysis of the purified protein complex in H2O and D2O and gel filtration, a mass of 270 kDa was calculated. The receptor has a s(20,w) of 9.4 and a Stoke's radius of 7.4 nm. The frictional coefficient was calculated to be 1.7 indicating a highly asymmetric protein complex compatible with a transmembrane protein forming an ion channel. The sequence of a peptide obtained after tryptic digestion of the 42-kDa protein allowed the specific identification of the Drosophila D alpha5 subunit by sequence comparison. A peptide-specific antibody raised against the D alpha5 subunit provides further evidence that this subunit is a component of an alpha-bungarotoxin binding nicotinic acetylcholine receptor from the central nervous system of Drosophila. PMID:15781463

Wu, Peipei; Ma, Dongdong; Pierzchala, Marek; Wu, Jun; Yang, Lee-Chuan; Mai, Xiaoping; Chang, Xiaoying; Schmidt-Glenewinkel, Thomas



Determination of alpha_s from the QCD static energy  

E-print Network

We compare lattice data for the short-distance part of the static energy in 2+1 flavor quantum chromodynamics (QCD) with perturbative calculations, up to next-to-next-to-next-to leading-logarithmic accuracy. We show that perturbation theory describes very well the lattice data at short distances, and exploit this fact to obtain a determination of the product of the lattice scale r_0 with the QCD scale Lambda_{MS}. With the input of the value of r_0, this provides a determination of the strong coupling alpha_s at the typical distance scale of the lattice data. We obtain alpha_s(1.5 GeV)=0.326\\pm0.019, which provides a novel determination of alpha_s at low energy and with three-loop accuracy (including resummation of the leading ultrasoft logarithms). When this value is evolved to the Z-mass scale M_Z, it corresponds to alpha_s(M_Z)=0.1156^{+0.0021}_{-0.0022}.

Alexei Bazavov; Nora Brambilla; Xavier Garcia i Tormo; Peter Petreczky; Joan Soto; Antonio Vairo



Learning about Alpha-1 Antitrypsin Deficiency (AATD)  


... disease in children and adults. Alpha-1 Association Genetic Counseling Service [] The Alpha-1 Association Genetic Counseling Center provides toll-free, confidential genetic counseling to ...


Triplicated alpha-globin loci in humans.  

PubMed Central

We have identified 12 individuals who are heterozygous for a chromosome with three alpha-globin genes. We determined the presence of the third alpha-globin locus by restriction endonuclease digestion and hybridization with alpha-globin cDNA probes. The three alpha-globin loci resided in an elongated fragment on digestion with EcoRI, BamHI, and Xba I, and the third locus was present in an additional 3.7-kilobase fragment on digestion with Hpa I, Sac I, and Bgl II. The locations of the restriction sites are compatible with a nonhomologous crossover mechanism producing the triple alpha loci. The frequency of the triple alpha loci was 0.0036 in American blacks and less than 0.004 in Sardinians, but was higher in Greek Crypriots (0.05). Individuals with five alpha-globin genes (alpha alpha/alpha alpha alpha) apparently showed no clinical or hematologic abnormalities. Images PMID:6928643

Goossens, M; Dozy, A M; Embury, S H; Zachariades, Z; Hadjiminas, M G; Stamatoyannopoulos, G; Kan, Y W



21 CFR 882.1610 - Alpha monitor.  

Code of Federal Regulations, 2011 CFR

... 2011-04-01 2011-04-01 false Alpha monitor. 882.1610 Section 882.1610...Neurological Diagnostic Devices § 882.1610 Alpha monitor. (a) Identification. An alpha monitor is a device with electrodes...



Alpha-1 Antitrypsin Deficiency (Inherited Emphysema)  


Alpha-1 Antitrypsin Deficiency Chronic obstructive pulmonary disease or COPD for short is a lung disease that ... disease. The inherited form of emphysema is called Alpha-1 Antitrypsin Deficiency or " Alpha-1 " for short. ...


How Is Alpha-1 Antitrypsin Deficiency Diagnosed?  


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Genetics Home Reference: Alpha-mannosidosis  


... 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 ...


How Is Alpha-1 Antitrypsin Deficiency Treated?  


... page from the NHLBI on Twitter. How Is Alpha-1 Antitrypsin Deficiency Treated? Alpha-1 antitrypsin (AAT) deficiency has no cure, but ... deficiency. Rate This Content: Next >> October 11, 2011 Alpha-1 Antitrypsin Deficiency Clinical Trials Clinical trials are ...


What Is Alpha-1 Antitrypsin Deficiency?  


... obstruction) to the ?ow of air. What causes Alpha-1? Alpha-1 is an inherited condition. Every ... two abnormal genes. Does everyone with two abnormal Alpha-1 genes develop disease? Not everyone who inherits ...


What Causes Alpha-1 Antitrypsin Deficiency?  


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Genetics Home Reference: 5-alpha reductase deficiency  


... Recent literature OMIM Genetic disorder catalog Conditions > 5-alpha reductase deficiency On this page: Description Genetic changes ... Glossary definitions Reviewed April 2008 What is 5-alpha reductase deficiency? 5-alpha reductase deficiency is a ...


Genetics Home Reference: Alpha-1 antitrypsin deficiency  


... PubMed Recent literature OMIM Genetic disorder catalog Conditions > Alpha-1 antitrypsin deficiency On this page: Description Genetic ... names Glossary definitions Reviewed January 2013 What is alpha-1 antitrypsin deficiency? Alpha-1 antitrypsin deficiency is ...


21 CFR 882.1610 - Alpha monitor.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 2010-04-01 false Alpha monitor. 882.1610 Section 882.1610...Neurological Diagnostic Devices § 882.1610 Alpha monitor. (a) Identification. An alpha monitor is a device with electrodes...



Quantization, Holography and the Universal Coefficient Theorem  

E-print Network

I present a method of performing geometric quantization using cohomology groups extended via coefficient groups of different types. This is possible according to the Universal Coefficient Theorem (UTC). I also show that by using this method new features of quantum field theory not visible in the previous treatments emerge. The main observation is that the ideas leading to the holographic principle can be interpreted in the context of the universal coefficient theorem from a totally different perspective.

Andrei T. Patrascu



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.



Stiffness and thermoelastic coefficients for composite laminates  

NASA Technical Reports Server (NTRS)

Simple analytic expressions are presented for the stiffness and thermoelastic coefficients of composite laminates in terms of the material properties of the individual layers. Expressions for the derivatives of the various coefficients with respect to each of the material properties and fiber orientation angles are also included. For typical high-performance composites, numerical values are given showing the effects of the stacking sequence and the fiber orientation angle of quasi-isotropic and angle-ply laminates on the values of the various coefficients and their sensitivity derivatives. The expressions for the thermoelastic coefficients and the sensitivity derivatives are given herein for the first time.

Noor, Ahmed K.; Tenek, Lazarus H.



Electron and hole impact ionization coefficients in GaAs-Al(x)Ga(1-x)As superlattices  

NASA Technical Reports Server (NTRS)

Electron and hole multiplication and impact ionization coefficients have been measured with pure carrier injection in p(+)-n(-)-n(+) diodes grown by molecular beam epitaxy. Values of the electron and hole ionization coefficient ratio alpha/beta = 2-5 are measured for superlattices with well width Lz greater than or equal to 100 A and alpha/beta greater than 10 is measured in a graded band-gap superlattice with a total well and barrier width LB + LZ = 120 A. The ratio decreases and becomes less than unity for smaller well sizes. This is caused by an increase in beta (E) while alpha (E) remains fairly constant. The results have been interpreted by considering varying hole confinement and scattering in the coupled quantum wells.

Juang, F.-Y.; Das, U.; Nashimoto, Y.; Bhattacharya, P. K.



[Alpha-1-antitrypsin deficiency].  


Alpha-1-antitrypsin (?1AT) deficiency is a genetic disorder that manifests as pulmonary emphysema and liver cirrhosis. ?1AT deficiency is the most common genetic cause of liver disease in children and also an underappreciated cause of liver disease in adults. The prevalence in the general population in Western Europe is approximately 1 in 2,000. The most common and severe deficiency allele is the Z variant (two alleles mutated). This variant is characterized by the accumulation of Z-?1AT polymers in the endoplasmic reticulum of hepatocytes leading to cell death and to a severe reduction of ?1AT in the serum. The latter results in a loss of its antiprotease activity and its ability to protect lung tissue. Thus far, there are only very limited therapeutic options in ?1AT deficiency. A more detailed understanding of the biology governing ?1AT biogenesis is required in order to identify new pharmacological agents and biomarkers. This review will present current knowledge on ?1AT deficiency and focus on recent discoveries and new strategies in the treatment of this disease. PMID:25311024

Bouchecareilh, Marion



Measurement of $\\alpha_{s}$ with Radiative Hadronic Events  

E-print Network

Hadronic final states with a hard isolated photon are studied using data taken at centre-of-mass energies around the mass of the Z0 boson with the OPAL detector at LEP. The strong coupling alpha S is extracted by comparing data and QCD predictions for event shape observables at average reduced centre-of-mass energies ranging from 24 GeV to 78 GeV, and the energy dependence of alpha S is studied. Our results are consistent with the running of alpha S as predicted by QCD and show that within the uncertainties of our analysis event shapes in hadronic Z0 decays with hard and isolated photon radiation can be described by QCD at reduced centre-of-mass energies. Combining all values from different event shape observables and energies gives alpha S (Mz)=0.1182 pm 0.0015(stat.) pm 0.0101(syst.).

Abbiendi, G; Åkesson, P F; Alexander, G; Anagnostou, G; Anderson, K J; Asai, S; Axen, D; Bailey, I; Barberio, E; Barillari, T; Barlow, R J; Batley, R J; Bechtle, P; Behnke, T; Bell, K W; Bell, P J; Bella, G; Bellerive, A; Benelli, G; Bethke, S; Biebel, O; Boeriu, O; Bock, P; Boutemeur, M; Braibant, S; Brown, R M; Burckhart, H J; Campana, S; Capiluppi, P; Carnegie, R K; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Ciocca, C; Csilling, A; Cuffiani, M; Dado, S; Dallavalle, M; de Roeck, A; De Wolf, E A; Desch, K; Dienes, B; Dubbert, J; Duchovni, E; Duckeck, G; Duerdoth, I P; Etzion, E; Fabbri, F; Ferrari, P; Fiedler, F; Fleck, I; Ford, M; Frey, A; Gagnon, P; Gary, J W; Geich-Gimbel, C; Giacomelli, G; Giacomelli, P; Giunta, M; Goldberg, J; Gross, E; Grunhaus, J; Gruwé, M; Sen-Gupta, A; Hajdu, C; Hamann, M; Hanson, G G; Harel, A; Hauschild, M; Hawkes, C M; Hawkings, R; Herten, G; Heuer, R D; Hill, J C; Horváth, D; Igo-Kemenes, P; Ishii, K; Jeremie, H; Jovanovic, P; Junk, T R; Kanzaki, J; Karlen, D; Kawagoe, K; Kawamoto, T; Keeler, R K; Kellogg, R G; Kennedy, B W; Kluth, S; Kobayashi, T; Kobel, M; Komamiya, S; Kramer, T; Krasznahorkays, A Jr; Krieger, P; Von Krogh, J; Kühl, T; Kupper, M; Lafferty, G D; Landsman, H; Lanske, D; Lellouch, D; Letts, J; Levinson, L; Lillich, J; Lloyd, S L; Loebinger, F K; Lü, J; Ludwig, A; Ludwig, J; Mader, W; Marcellini, S; Martin, A J; Mashimo, T; Mättig, P; McKenna, J; McPherson, R A; Meijers, F; Menges, W; Merritt, F S; Mes, H; Meyer, N; Michelini, A; Mihara, S; Mikenberg, G; Miller, D J; Mohr, W; Mori, T; Mutter, A; Nagai, K; Nakamura, I; Nanjo, H; Neal, H A; O'Neale, S W; Oh, A; Oreglia, M J; Orito, S; Pahl, C; Pásztor, G; Pater, J R; Pilcher, J E; Pinfold, J L; Plane, D E; Pooth, O; Przybycien, M; Quadt, A; Rabbertz, K; Rembser, C; Renkel, P; Roney, J M; Rossi, A M; Rozen, Y; Runge, K; Sachs, K; Saeki, T; Sarkisyan-Grinbaum, E; Schaile, A D; Schaile, O; Scharff-Hansen, P; Schiecks, J; Schörner-Sadenius, T; Schröder, M; Schumacher, M; Seuster, R; Shears, T G; Shen, B C; Sherwood, P; Skuja, A; Smith, A M; Sobie, R J; Söldner-Rembold, S; Spanó, F; Stahl, A; Strom, D; Ströhmer, R; Tarem, S; Tasevsky, M; Teuscher, R; Thomson, M A; Torrence, E; Toya, D; Trigger, I; Trócsányi, Z L; Tsur, E; Turner-Watson, M F; Ueda, I; Ujvári, B; Vollmer, C F; Vannerem, P; Vertesi, R; Verzocchi, M; Voss, H; Vossebeld, J; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wengler, T; Wermes, N; Wilson, G W; Wilson, J A; Wolf, G; Wyatt, T R; Yamashita, S; Zer-Zion, D; Zivkovic, L



Treatment of recurrent genital herpes with interferon alpha-2alpha.  


The purpose of the present study was to evaluate the efficacy and safety of parenteral administration of interferon alpha-2alpha in the treatment of recurrent herpes genitalis. A total of 97 patients (66 males, 31 females, mean age 34.86 +/-16.74 years), who had at least five recurrences of genital herpes during the previous 12 months, participated in a prospective open study on the effects of treatment with interferon alpha-2alpha (Roferon-A; Roche). The patients were treated with interferon alpha-2alpha (3 x 10(6) IU) by subcutaneous injection, three times weekly for 4 weeks, and the same schedule was repeated after 3 and 6 months. All patients were asymptomatic at the start of the study. After initiation of treatment, all patients reported to the clinic every 3 months for 2 years (the males were submitted to peoscopy and the females to Pap test and colposcopy) at the time of their recurrences. Comparison was made of the number of recurrences, duration of lesions, duration and severity of pain, and itching and burning. Prophylactic administration of interferon alpha-2alpha prevented recurrences of genital herpes virus infection in 51 patients (20 males and 31 females). Interferon administration shortened the healing time from 8.5 days before treatment to 2.5 days after treatment (p < 0.001). There was a significant reduction in the number of recurrences during the study period, from 7.46 before treatment to 2.64 after treatment (p < 0.001). On the basis of the overall efficacy and adverse effects, this regimen may be of value in the routine treatment of recurrent herpes. PMID:9692344

Cardamakis, E; Relakis, K; Kotoulas, I G; Michopoulos, J; Metallinos, K; Mantouvalos, H; Tzingounis, V



Friction Coefficient for Quarks in Supergravity Duals  

E-print Network

We study quarks moving in strongly-coupled plasmas that have supergravity duals. We compute the friction coefficient of strings dual to such quarks for general static supergravity backgrounds near the horizon. Our results also show that a previous conjecture on the bound has to be modified and higher friction coefficients can be achieved.

E. Antonyan



Calculator program set up for film coefficients  

Microsoft Academic Search

Describes a mechanized computation scheme for the film coefficients used in heat transfer calculations designed for the Texas Instruments TI-59 programmable calculator. Presents tables showing application conditions (small diagram included) and the corresponding heat transfer equations for 10 heat flow situations; symbols used; user instructions, a complete film coefficient program; and storage assignments. Example problem and corresponding printout are given.

J. O. Gracey; D. L. Teter



Calculator program set up for film coefficients  

SciTech Connect

Describes a mechanized computation scheme for the film coefficients used in heat transfer calculations designed for the Texas Instruments TI-59 programmable calculator. Presents tables showing application conditions (small diagram included) and the corresponding heat transfer equations for 10 heat flow situations; symbols used; user instructions, a complete film coefficient program; and storage assignments. Example problem and corresponding printout are given.

Gracey, J.O.; Teter, D.L.



APPENDIX G Partition Coefficients For Plutonium  

E-print Network

APPENDIX G Partition Coefficients For Plutonium #12;Appendix G Partition Coefficients For Plutonium G.1.0 Background A number of studies have focussed on the adsorption behavior of plutonium that Kd values for plutonium typically range over 4 orders of magnitude (Thibault et al., 1990). Also


Transport coefficients of the QGP Alessandro Amato  

E-print Network

Transport coefficients of the QGP Alessandro Amato Department of Physics, College of Science;Transport coefficients of the QGP Alessandro Amato 1. Introduction In this work we study the dynamical properties of the quark-gluon plasma (QGP), and in particular we focus on the transport phenomena associated

Aarts, Gert



Microsoft Academic Search

Coulomb field effects on K shell internal conversion coefficients for ; threshold values of the gamma-ray energy are investigated using exact wave ; functions to describe both the bound and the continuum state electrons. Exact ; results for the internal conversion coefficients are obtained in terms of gamma ; functions and confluent hypergeometric functions. To facilitate numerical ; evaluation, the




APPENDIX H Partition Coefficients For Strontium  

E-print Network

APPENDIX H Partition Coefficients For Strontium #12;Appendix H Partition Coefficients For Strontium H.1.0 Background Two simplifying assumptions underlying the selection of strontium Kd values included in the look-up table were made. These assumptions are that the adsorption of strontium adsorption


Generalized Fibonacci polynomials and Fibonomial coefficients  

E-print Network

, Fibonacci number, Fibonomial coefficient, Lucas number q-analogue, valuation AMS subject classificationGeneralized Fibonacci polynomials and Fibonomial coefficients Tewodros Amdeberhan Department (2000): Primary 05A10; Secondary 11B39, 11B65. Running title: Fibonacci polynomials and Fibonomial

Sagan, Bruce


Implications of NGA for NEHRP site coefficients  

USGS Publications Warehouse

Three proposals are provided to update tables 11.4-1 and 11.4-2 of Minimum Design Loads for Buildings and Other Structures (7-10), by the American Society of Civil Engineers (2010) (ASCE/SEI 7-10), with site coefficients implied directly by NGA (Next Generation Attenuation) ground motion prediction equations (GMPEs). Proposals include a recommendation to use straight-line interpolation to infer site coefficients at intermediate values of ?vs (average shear velocity). Site coefficients are recommended to ensure consistency with ASCE/SEI 7-10 MCER (Maximum Considered Earthquake) seismic-design maps and simplified site-specific design spectra procedures requiring site classes with associated tabulated site coefficients and a reference site class with unity site coefficients. Recommended site coefficients are confirmed by independent observations of average site amplification coefficients inferred with respect to an average ground condition consistent with that used for the MCER maps. The NGA coefficients recommended for consideration are implied directly by the NGA GMPEs and do not require introduction of additional models.

Borcherdt, Roger D.



Fractal fractal dimensions of deterministic transport coefficients  

Microsoft Academic Search

If a point particle moves chaotically through a periodic array of scatterers th ea ssociated transport coefficients are typically irregular functions under variation of control parameters. For a piecewise linear two-parameter map we analyse the structure of the associated irregular diffusion coefficient and current by numerically computing dimensions from box-counting and from the autocorrelation function of these graphs. We find

TU Dresden; Fachrichtung Mathematik


APPENDIX C Partition Coefficients For Cadmium  

E-print Network

APPENDIX C Partition Coefficients For Cadmium #12;Appendix C Partition Coefficients For Cadmium C.1.0 Background Cadmium Kd values and some important ancillary parameters that have been shown to influence cadmium sorption were collected from the literature and tabulated. Data included in this data set


PCC/SRC. Correlation & Regression Coefficients  

SciTech Connect

PCC/SRC is designed for use in conjunction with sensitivity analyses of complex computer models. PCC/SRC calculates the partial correlation coefficients (PCC) and the standardized regression coefficients (SRC) from the multivariate input to, and output from, a computer model.

Iman, R.L.; Shortencarier, M.J.; Johnson, J.D. [Sandia National Labs., Albuquerque, NM (United States)



Interlaboratory Comparison of Ultrasonic Backscatter Coefficient  

E-print Network

Interlaboratory Comparison of Ultrasonic Backscatter Coefficient Measurements From 2 to 9 MHz Keith coefficient is a fundamental ultrasonic property that has been used to character- ize many tissues. Unfortunately, there is currently far less standardization for the ultrasonic backscatter measurement than

Illinois at Urbana-Champaign, University of


Prediction of friction coefficients for gases  

NASA Technical Reports Server (NTRS)

Empirical relations are used for correlating laminar and turbulent friction coefficients for gases, with large variations in the physical properties, flowing through smooth tubes. These relations have been used to correlate friction coefficients for hydrogen, helium, nitrogen, carbon dioxide and air.

Taylor, M. F.



Coefficient of Earth Pressure at Rest  

Microsoft Academic Search

The widely used Jaky coefficient of earth pressure at rest, K0, is revisited. It is demonstrated that this coefficient was derived from an analysis of the stress state in a sand prism that yields an unrealistic stress field. It is also surprising that the at rest stress state is represented as a function of the limit state parameter internal friction

Radoslaw L. Michalowski



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)



Rational Functions With Nonnegative Integer Coefficients  

E-print Network

Rational Functions With Nonnegative Integer Coefficients Ira Gessel Brandeis University Waltham, MA Saint-Jacques #12;1. When are the coefficients of a rational function nonnegative? 2. When (if interpretation for a rational generating function? The transfer matrix method. Let M be a matrix and let

Gessel, Ira M.


APPENDIX J Partition Coefficients For Uranium  

E-print Network

APPENDIX J Partition Coefficients For Uranium #12;Appendix J Partition Coefficients For Uranium J.1.0 Background The review of uranium Kd values obtained for a number of soils, crushed rock and their effects on uranium adsorption on soils are discussed below. The solution pH was also used as the basis


An agreement coefficient for image comparison  

USGS Publications Warehouse

Combination of datasets acquired from different sensor systems is necessary to construct a long time-series dataset for remotely sensed land-surface variables. Assessment of the agreement of the data derived from various sources is an important issue in understanding the data continuity through the time-series. Some traditional measures, including correlation coefficient, coefficient of determination, mean absolute error, and root mean square error, are not always optimal for evaluating the data agreement. For this reason, we developed a new agreement coefficient for comparing two different images. The agreement coefficient has the following properties: non-dimensional, bounded, symmetric, and distinguishable between systematic and unsystematic differences. The paper provides examples of agreement analyses for hypothetical data and actual remotely sensed data. The results demonstrate that the agreement coefficient does include the above properties, and therefore is a useful tool for image comparison. ?? 2006 American Society for Photogrammetry and Remote Sensing.

Ji, L.; Gallo, K.



The wear coefficient - Magnitude, scatter, uses  

NASA Astrophysics Data System (ADS)

One of the key factors in the analysis of a wear problem is the computation of the wear coefficient for a comparison with the value to be anticipated for this application. Typical values of adhesive wear coefficients for a variety of materials and lubricants are presented, and the values compared with those arising in the wear modes of abrasion, corrosion and fretting. A major uncertainty arises from the fact that wear coefficients show considerable variation, both in repeat testing, and in the testing of different materials that presumably should have the same wear coefficient. Quantitative values for the scatter encountered in adhesive wear situations are given and discussed. Various uses of the wear coefficient in the analysis of sliding systems are illustrated.

Rabinowicz, E.



Alpha Ori - Evidence for pulsation  

NASA Technical Reports Server (NTRS)

The study deals with a periodic modulation of the UV continuum and Mg II emission-line fluxes shown by the bright cool supergiant Alpha Orionis; this pulsation is identified with the supergiant's atmosphere. UV brightness is shown to occur near the time of maximum outflow velocity of the photosphere, while local minima in the UV continuum occur near the time of maximum infall velocity. Visible and UV observations of Alpha Ori since the beginning of the monitoring program with IUE are discussed.

Dupree, A. K.; Baliunas, S. L.; Hartmann, L.; Guinan, E. F.; Sonneborn, G.



3 Properties of Binomial Coefficients 3.1 Properties of Binomial Coefficients  

E-print Network

coefficients are also found in Pascal's triangle. Pascal's triangle has the rule that each entry is the sum. Here is the start of Pascal's triangle with the odd binomial coefficients shaded. c Wayne Goddard

Goddard, Wayne


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




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)



Path-Counting Formulas for Generalized Kinship Coefficients and Condensed Identity Coefficients  

PubMed Central

An important computation on pedigree data is the calculation of condensed identity coefficients, which provide a complete description of the degree of relatedness of two individuals. The applications of condensed identity coefficients range from genetic counseling to disease tracking. Condensed identity coefficients can be computed using linear combinations of generalized kinship coefficients for two, three, four individuals, and two pairs of individuals and there are recursive formulas for computing those generalized kinship coefficients (Karigl, 1981). Path-counting formulas have been proposed for the (generalized) kinship coefficients for two (three) individuals but there have been no path-counting formulas for the other generalized kinship coefficients. It has also been shown that the computation of the (generalized) kinship coefficients for two (three) individuals using path-counting formulas is efficient for large pedigrees, together with path encoding schemes tailored for pedigree graphs. In this paper, we propose a framework for deriving path-counting formulas for generalized kinship coefficients. Then, we present the path-counting formulas for all generalized kinship coefficients for which there are recursive formulas and which are sufficient for computing condensed identity coefficients. We also perform experiments to compare the efficiency of our method with the recursive method for computing condensed identity coefficients on large pedigrees. PMID:25165486

Cheng, En; Ozsoyoglu, Z. Meral



Selective binding of collagen subtypes by integrin alpha 1I, alpha 2I, and alpha 10I domains.  


Four integrins, namely alpha(1)beta(1), alpha(2)beta(1), alpha(10)beta(1), and alpha(11)beta(1), form a special subclass of cell adhesion receptors. They are all collagen receptors, and they recognize their ligands with an inserted domain (I domain) in their alpha subunit. We have produced the human integrin alpha(10)I domain as a recombinant protein to reveal its ligand binding specificity. In general, alpha(10)I did recognize collagen types I-VI and laminin-1 in a Mg(2+)-dependent manner, whereas its binding to tenascin was only slightly better than to albumin. When alpha(10)I was tested together with the alpha(1)I and alpha(2)I domains, all three I domains seemed to have their own collagen binding preferences. The integrin alpha(2)I domain bound much better to fibrillar collagens (I-III) than to basement membrane type IV collagen or to beaded filament-forming type VI collagen. Integrin alpha(1)I had the opposite binding pattern. The integrin alpha(10)I domain was similar to the alpha(1)I domain in that it bound very well to collagen types IV and VI. Based on the previously published atomic structures of the alpha(1)I and alpha(2)I domains, we modeled the structure of the alpha(10)I domain. The comparison of the three I domains revealed similarities and differences that could potentially explain their functional differences. Mutations were introduced into the alphaI domains, and their binding to types I, IV, and VI collagen was tested. In the alpha(2)I domain, Asp-219 is one of the amino acids previously suggested to interact directly with type I collagen. The corresponding amino acid in both the alpha(1)I and alpha(10)I domains is oppositely charged (Arg-218). The mutation D219R in the alpha(2)I domain changed the ligand binding pattern to resemble that of the alpha(1)I and alpha(10)I domains and, vice versa, the R218D mutation in the alpha(1)I and alpha(10)I domains created an alpha(2)I domain-like ligand binding pattern. Thus, all three collagen receptors appear to differ in their ability to recognize distinct collagen subtypes. The relatively small structural differences on their collagen binding surfaces may explain the functional specifics. PMID:11572855

Tulla, M; Pentikäinen, O T; Viitasalo, T; Käpylä, J; Impola, U; Nykvist, P; Nissinen, L; Johnson, M S; Heino, J



Modeling satellite drag coefficients with response surfaces  

NASA Astrophysics Data System (ADS)

Satellite drag coefficients are a major source of uncertainty in predicting the drag force on satellites in low Earth orbit. Among other things, accurately predicting the orbit requires detailed knowledge of the satellite drag coefficient. Computational methods are an important tool in computing the drag coefficient but are too intensive for real-time and predictive applications. Therefore, analytic or empirical models that can accurately predict drag coefficients are desired. This work uses response surfaces to model drag coefficients. The response surface methodology is validated by developing a response surface model for the drag coefficient of a sphere where the closed-form solution is known. The response surface model performs well in predicting the drag coefficient of a sphere with a root mean square percentage error less than 0.3% over the entire parameter space. For more complex geometries, such as the GRACE satellite, the Hubble Space Telescope, and the International Space Station, the model errors are only slightly larger at about 0.9%, 0.6%, and 1.0%, respectively.

Mehta, Piyush M.; Walker, Andrew; Lawrence, Earl; Linares, Richard; Higdon, David; Koller, Josef



A study of multiplicative watermark detection in the contourlet domain using alpha-stable distributions.  


In the past decade, several schemes for digital image watermarking have been proposed to protect the copyright of an image document or to provide proof of ownership in some identifiable fashion. This paper proposes a novel multiplicative watermarking scheme in the contourlet domain. The effectiveness of a watermark detector depends highly on the modeling of the transform-domain coefficients. In view of this, we first investigate the modeling of the contourlet coefficients by the alpha-stable distributions. It is shown that the univariate alpha-stable distribution fits the empirical data more accurately than the formerly used distributions, such as the generalized Gaussian and Laplacian, do. We also show that the bivariate alpha-stable distribution can capture the across scale dependencies of the contourlet coefficients. Motivated by the modeling results, a blind watermark detector in the contourlet domain is designed by using the univariate and bivariate alpha-stable distributions. It is shown that the detectors based on both of these distributions provide higher detection rates than that based on the generalized Gaussian distribution does. However, a watermark detector designed based on the alpha-stable distribution with a value of its parameter ? other than 1 or 2 is computationally expensive because of the lack of a closed-form expression for the distribution in this case. Therefore, a watermark detector is designed based on the bivariate Cauchy member of the alpha-stable family for which ? = 1 . The resulting design yields a significantly reduced-complexity detector and provides a performance that is much superior to that of the GG detector and very close to that of the detector corresponding to the best-fit alpha-stable distribution. The robustness of the proposed bivariate Cauchy detector against various kinds of attacks, such as noise, filtering, and compression, is studied and shown to be superior to that of the generalized Gaussian detector. PMID:25051554

Sadreazami, Hamidreza; Ahmad, M Omair; Swamy, M N S



Negative normal restitution coefficient for nanocluster collisions  

E-print Network

The oblique impact of nanoclusters is studied by means of Molecular Dynamics simulation. Using the standard definition of the normal restitution coefficient $e$ we observe a surprising result, that $e$ becomes negative for large incident angles. We show that this effect may be attributed to the reorientation of the contact plane during collisions, which affects $e$. We propose a modified definition of the normal restitution coefficient $\\Tilde{e}$. This, in contrast to the standard definition, characterizes exclusively the normal motion and is always positive. We develop a simple theoretical model of an oblique impact, which explains the observed behavior of the restitution coefficients and agrees well with the numerical data.

Brilliantov, Nikolai V



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.



Transport coefficients of a unitarized pion gas  

E-print Network

The latest experimental results in relativistic heavy-ion collisions show that the matter there produced requires transport coefficients because of the important collective properties found. We review the theoretical calculation of these transport coefficients in the hadron side at low temperatures by computing them in a gas composed of low energy pions. The interaction of these pions is taken from an effective chiral theory and further requiring scattering unitarity. The propagation of D and D* mesons in the thermalized pion gas is also studied in order to extract the heavy quark diffusion coefficients in the system.

Juan M. Torres-Rincon



Coefficient of restitution of aspherical particles  

NASA Astrophysics Data System (ADS)

We consider the motion of an aspherical inelastic particle of dumbbell type bouncing repeatedly on a horizontal flat surface. The coefficient of restitution of such a particle depends not only on material properties and impact velocity but also on the angular orientation at the instant of the collision whose variance is considerable, even for small eccentricity. Assuming random angular orientation of the particle at the instant of contact we characterize the measured coefficient of restitution as a fluctuating quantity and obtain a wide probability density function including a finite probability for negative values of the coefficient of restitution. This may be understood from the partial exchange of translational and rotational kinetic energy.

Glielmo, Aldo; Gunkelmann, Nina; Pöschel, Thorsten



Container structure of alpha alpha Lambda clusters in $_?^9$Be  

E-print Network

New concept of clustering is discussed in $\\Lambda$ hypernuclei using a new-type microscopic cluster model wave function, which has a structure that constituent clusters are confined in a container, whose size is a variational parameter and which we refer to as Hyper-Tohsaki-Horiuchi-Schuck-R\\"opke (Hyper-THSR) wave function. By using the Hyper-THSR wave function, $2\\alpha + \\Lambda$ cluster structure in ${^{9}_\\Lambda{\\rm Be}}$ is investigated. We show that full microscopic solutions in the $2\\alpha + \\Lambda$ cluster system, which are given as $2\\alpha + \\Lambda$ Brink-GCM wave functions, are almost perfectly reproduced by the single configurations of the Hyper-THSR wave function. The squared overlaps between the both wave functions are calculated to be $99.5$%, $99.4$%, and $97.7$% for $J^\\pi=0^+$, $2^+$, and $4^+$ states, respectively. We also simulate the structural change by adding the $\\Lambda$ particle, by varying the $\\Lambda N$ interaction artificially. As the increase of the $\\Lambda N$ interaction, the $\\Lambda$ particle gets to move more deeply inside the core and invokes strongly the spatial core shrinkage, and accordingly distinct localized $2\\alpha$ clusters appear in the nucleonic intrinsic density, though in ${^{8}{\\rm Be}}$ rather gaslike $2\\alpha$-cluster structure is shown. The origin of the localization is associated with the strong effect of Pauli principle. We conclude that the container picture of the $2\\alpha$ and $\\Lambda$ clusters is essential in understanding the cluster structure in ${^{9}_\\Lambda{\\rm Be}}$, in which the very compact spatial localization of clusters is shown in the density distribution.

Y. Funaki; T. Yamada; E. Hiyama; B. Zhou; K. Ikeda



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



The Cycles of Alpha Centauri  

NASA Astrophysics Data System (ADS)

The main AB pair of the nearby Alpha Centauri triple system has an extensive X-ray history, covering three decades. Alpha Cen A (G2V) is a near twin of the Sun, with a similarly soft (1-2 MK) corona. Alpha Cen B (K1V) is more active than the Sun, with a generally harder X-ray spectrum. Here, spatially resolved measurements from ROSAT, XMM-Newton, and Chandra are compared on a common basis. In the combined time series, Alpha Cen B shows a distinct X-ray modulation with a period of about eight years and a factor of 5 cycle depth (the latter is similar to the Sun's). Alpha Cen A showed minimal variability 1995-2000, a decrease in the initial XMM epoch 2003-2005, and nearly constant behavior in the subsequent Chandra segment (late-2005 to present), although down a factor of 2 from the mid-1990's level. A remarkable ``smoking gun'' LETGS spectrum in mid-2007 emphasized that much of the coronal luminosity of solar-activity objects falls at longer wavelengths than recorded efficiently by contemporary instruments. This makes cycle depth strongly dependent on the energy bandpass of the measurement (here 0.2-2 keV), and complicates assessments of coronal heating requirements.

Ayres, Thomas



Friction coefficient dependence on electrostatic tribocharging  

NASA Astrophysics Data System (ADS)

Friction between dielectric surfaces produces patterns of fixed, stable electric charges that in turn contribute electrostatic components to surface interactions between the contacting solids. The literature presents a wealth of information on the electronic contributions to friction in metals and semiconductors but the effect of triboelectricity on friction coefficients of dielectrics is as yet poorly defined and understood. In this work, friction coefficients were measured on tribocharged polytetrafluoroethylene (PTFE), using three different techniques. As a result, friction coefficients at the macro- and nanoscales increase many-fold when PTFE surfaces are tribocharged, but this effect is eliminated by silanization of glass spheres rolling on PTFE. In conclusion, tribocharging may supersede all other contributions to macro- and nanoscale friction coefficients in PTFE and probably in other insulating polymers.

Burgo, Thiago A. L.; Silva, Cristiane A.; Balestrin, Lia B. S.; Galembeck, Fernando



Feature extraction through discrete wavelet transform coefficients  

NASA Astrophysics Data System (ADS)

Discrete wavelet transform has become a widely used feature extraction tool in pattern recognition and pattern classification applications. However, using all wavelet coefficients as features is not desirable in most applications -- the enormity of data and irrelevant wavelet coefficients may adversely affect the performance. Therefore, this paper presents a novel feature extraction method based on discrete wavelet transform. In this method, Shannon's entropy measure is used for identifying competent wavelet coefficients. The features are formed by calculating the energy of coefficients clustered around the competent clusters. The method is applied to the lung sound classification problem. The experimental results show that the new method performs better than a well-known feature extraction method that is known to give the best results for lung sound classification problem.

Icke, Guzide; Kamarthi, Sagar V.



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



Graphing correlation coefficients: II. An alternative procedure.  


A procedure based on the Pythagorean theorem is described for accurately portraying the relationships among the coefficients of correlation (r), determination (r2), nondetermination (1 - r2), and alienation (square root of 1 - r2). PMID:3226839

Silverstein, A B



An energy-dependent electron backscattering coefficient  

NASA Astrophysics Data System (ADS)

An energy-dependent electron backscattering coefficient is derived based on the continuous slowing down approximation and the Bethe stopping power. Backscattering coefficients are given for 10-50-keV electrons incident on bulk and thin-film aluminum, silver, and gold targets. The results are compared with the Everhart theory and empirical fits to experimental data. The energy-dependent theory agrees better with experimental work.

Williamson, W., Jr.; Antolak, A. J.; Meredith, R. J.



Coefficient of friction of composite delamination surfaces  

Microsoft Academic Search

The coefficient of friction of delamination surfaces from graphite fiber\\/epoxy matrix (IM7\\/8552) composites has been measured in reciprocating sliding. The worn surfaces were examined with a scanning electron microscope and the friction and wear mechanisms were studied. The results show that after an initial wear-in of the surfaces the coefficient of friction will decrease with increasing number of reciprocal cycles

Joakim Schön



Space Station alpha joint bearing  

NASA Technical Reports Server (NTRS)

Perhaps the most critical structural system aboard the Space Station is the Solar Alpha Rotary Joint which helps align the power generation system with the sun. The joint must provide structural support and controlled rotation to the outboard transverse booms as well as power and data transfer across the joint. The Solar Alpha Rotary Joint is composed of two transition sections and an integral, large diameter bearing. Alpha joint bearing design presents a particularly interesting problem because of its large size and need for high reliability, stiffness, and on orbit maintability. The discrete roller bearing developed is a novel refinement to cam follower technology. It offers thermal compensation and ease of on-orbit maintenance that are not found in conventional rolling element bearings. How the bearing design evolved is summarized. Driving requirements are reviewed, alternative concepts assessed, and the selected design is described.

Everman, Michael R.; Jones, P. Alan; Spencer, Porter A.



Ly-alpha polarimeter design for CLASP rocket experiment  

NASA Astrophysics Data System (ADS)

A sounding-rocket program called the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is proposed to be launched in the Summer of 2014. CLASP will observe the upper solar chromosphere in Ly-alpha (121.567 nm), aiming to detect the linear polarization signal produced by scattering processes and the Hanle effect for the first time. The CLASP needs a rotating half-waveplate and a polarization analyzer working at the Ly-alpha wavelength to measure the linear polarization signal. We select Magnesium Fluoride (MgF2) as a material of the optical components because of its birefringent property and high transparency at UV wavelength. We have confirmed that the reflection at the Brewster's Angle of MgF2 plate is a good polarization analyzer for the Ly-alpha line by deriving its ordinary refractive index and extinction coefficient along the ordinary and extraordinary axes. These optical parameters are calculated with a least-square fitting in such a way that the reflectance and transmittance satisfy the Kramers-Kronig relation. The reflectance and transmittance against oblique incident angles for the s-polarized and the p-polarized light are measured using the synchrotron beamline at the Ultraviolet Synchrotron Orbital Radiation Facility (UVSOR). We have also measured a retardation of a zeroth-order waveplate made of MgF2. The thickness difference of the waveplate is 14.57 um.This waveplate works as a half-waveplate at 121.74 nm. From this measurement, we estimate that a waveplate with the thickness difference of 15.71 um will work as a half-waveplate at the Ly-alpha wavelength. We have developed a rotating waveplate - polarization analyzer system called a prototype of CLASP polarimeter, and input the perfect Stokes Q and U signals. The modulation patterns that are consistent with the theoretical prediction are successfully obtained in both cases.

Kubo, M.; Watanabe, H.; Narukage, N.; Ishikawa, R.; Bando, T.; Kano, R.; Tsuneta, S.; Kobayashi, K.; Ichimoto, K.; Trujillo Bueno, J.; Song, D.



Bremsstrahlung in {alpha} Decay Reexamined  

SciTech Connect

A high-statistics measurement of bremsstrahlung emitted in the {alpha} decay of {sup 210}Po has been performed, which allows us to follow the photon spectra up to energies of {approx}500 keV. The measured differential emission probability is in good agreement with our theoretical results obtained within the quasiclassical approximation as well as with the exact quantum mechanical calculation. It is shown that, due to the small effective electric dipole charge of the radiating system, a significant interference between the electric dipole and quadrupole contributions occurs, which is altering substantially the angular correlation between the {alpha} particle and the emitted photon.

Boie, H.; Scheit, H.; Jentschura, U. D.; Koeck, F.; Lauer, M.; Schwalm, D. [Max-Planck-Institut fuer Kernphysik, D-69117 Heidelberg (Germany); Milstein, A. I.; Terekhov, I. S. [Budker Institute of Nuclear Physics, 630090 Novosibirsk (Russian Federation)



NACA Physicist Studying Alpha Rays  

NASA Technical Reports Server (NTRS)

NACA Physicits studying Alpha Rays in a continuous cloud chamber. A cloud chamber is used by Lewis scientists to obtain information aimed at minimizing undesirable effects of radiation on nuclear-powered aircraft components. Here, alpha particles from a polonium source emit in a flower-like pattern at the cloud chamber's center. The particles are made visible by means of alcohol vapor diffusing from an area at room temperature to an area at minus -78 deg. Centigrade. Nuclear-powered aircraft were never developed and aircraft nuclear propulsion systems were canceled in the early 1960s.



Simulating the Lyman Alpha Forest  

E-print Network

In this paper we review the importance of the Lyman alpha forest as a probe of structure formation in the universe. We first discuss the statistics used to describe the Lyman alpha forest and the numerical techniques used to produce simulated spectra of the forest from a given cosmological model. We then discuss the physical picture of the absorbing structures that emerges from these numerical simulations. Finally, we comment on how two of the statistics, the slope of the column density distribution and the b parameter distribution, may be used to constrain competing cosmologies.

Marie E. Machacek; Greg L. Bryan; Peter Anninos; Avery Meiksin; Michael L. Norman



alpha_s From the Lattice and Hadronic Tau Decays  

E-print Network

Until recently, determinations of alpha_s(M_Z) from hadronic tau decays and the analysis of short-distance-sensitive lattice observables yielded results which, though precise, were not in good agreement. I review new analyses that bring these into good agreement and provide some details on the source of the main changes in the tau decay analysis.

Kim Maltman



Simultaneous determination of the tissue light scattering coefficient and Brownian diffusion coefficient using optical coherence tomography  

NASA Astrophysics Data System (ADS)

Diseased tissue has different optical properties and dynamic behaviors from normal tissue, and this can be exploited for diagnostics and therapeutics. We present a model for simultaneously estimating the optical scattering coefficient and Brownian diffusion coefficient of superficial biological tissue. This theoretical model predicts that the U-quadratic distribution approximates the Lorentzian power spectrum due to the Brownian motion, when the frequency width of integration is much less than the power spectrum linewidth. Furthermore, it shows that the logarithmic intensity of all calculated wavelet frequencies is linearly dependent on the scattering coefficient and the standard deviation of the Doppler frequency shift is linearly dependent on the Brownian diffusion coefficient in the region of the single scattering length. An optical coherence tomography system was used to measure the optical scattering coefficient and the Brownian diffusion coefficient of phantoms. The results of our theoretical model are consistent with the experimental results. Thus, the method has the potential for diagnosis of diseases.

Li, Zhifang; Lin, Xiaona; Li, Hui; Chen, Wei R.



Scattering of alpha particles by 22Ne  

Microsoft Academic Search

Differential cross sections at a few angles for 22Ne(alpha,alphai)22Ne are reported for alphai=alpha0, alpha1, and alpha2 mainly in 10 keV steps for 22alpha,alpha), 13.4<=Ealpha (MeV)<=20,8, elastic and inelastic (2+, 1.27 MeV and 4+, 3.36 MeV). Measured sigma(theta,Ealpha) at one or two angles.

C. A. Davis



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:; 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)



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



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



The Effects of Methods of Imputation for Missing Values on the Validity and Reliability of Scales  

ERIC Educational Resources Information Center

The main aim of this study is the comparative examination of the factor structures, corrected item-total correlations, and Cronbach-alpha internal consistency coefficients obtained by different methods used in imputation for missing values in conditions of not having missing values, and having missing values of different rates in terms of testing…

Cokluk, Omay; Kayri, Murat



A Brief Screening Instrument for Assessing Parental Alcoholism in College Student Populations  

Microsoft Academic Search

The Children of Alcoholics Short Screening Instrument (CASSI), a four-item Likert-type scale, was developed to fulfill the need for a screening instrument to identify children of alcoholics (COAs) in college student populations. A sample of 369 college students was surveyed to assess the psychometric properties of the CASSI; the scale had a Cronbach alpha reliability coefficient of .94 and a

Karen Vail-Smith; Sharon M. Knight; Thomas W. Durham



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



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.



Validation of the Trait Anxiety Scale for State-Trait Anxiety Inventory in Suicide Victims and Living Controls of Chinese Rural Youths  

Microsoft Academic Search

This study evaluated the validation of STAI Trait-Anxiety Scale in suicide cases and community living controls in rural China. The participants were 392 suicides and 416 controls. Cronbach's Alpha was computed to evaluate the internal consistency. The Spearman Correlation Coefficient between Trait-Anxiety Scale and other instrument was calculated to evaluate the external validity, and the Exploratory Factor Analysis was used

Jie Zhang; Qi Gao



Developing a Scientific Literacy for University Students in Geography Education Branch about Strengthened Greenhouse Effect \\/ Global Climatic Change and Ozone Depletion: It's Validity and Reliability  

Microsoft Academic Search

The aim of this study is to develop a survey to measure the level of scientific literacy for university students in Geography Education Branch about strengthened greenhouse effect \\/ global climatic change and ozone depletion. A survey of 20 items was developed in this research and conducted among 150 students. The Cronbach alpha coefficient was .82 for overall survey and

Ülkü Eser Ünaldi; Merve Görkem Bilgi


Nonstrict inequality for Schmidt coefficients of three-qubit states  

NASA Astrophysics Data System (ADS)

Generalized Schmidt decomposition of pure three-qubit states has four positive and one complex coefficients. In contrast to the bipartite case, they are not arbitrary and the largest Schmidt coefficient restricts severely other coefficients. We derive a nonstrict inequality between three-qubit Schmidt coefficients, where the largest coefficient defines the least upper bound for the three nondiagonal coefficients or, equivalently, the three nondiagonal coefficients together define the greatest lower bound for the largest coefficient. In addition, we show the existence of another inequality which should establish an upper bound for the remaining Schmidt coefficient.

Tamaryan, Levon



Longitudinal dispersion coefficients in natural channels.  


Details are given herein, of the development of an equation for predicting the longitudinal dispersion coefficient in riverine flows, based on 81 sets of measured data, and obtained from 30 rivers in the USA. This equation relates the dispersion coefficient to the hydraulic and geometric parameters of the flow and has been derived using dimensional and regression analysis, with a high correlation coefficient (i.e. R2 = 0.84). The formulation has been compared with many other existing empirical equations, frequently used to predict the longitudinal dispersion coefficient in riverine flows, with the comparisons based on four different statistical methods. These statistical comparisons have shown that the new equation appears to be more accurate than the other equations considered. The new dispersion equation was then linearly combined with a similar equation recently proposed by Seo and Cheong (J. Hydraul. Eng. ASCE 124 (1998) 25) and this combined equation was then also analysed using statistical methods. The existing empirical equations used to estimate the longitudinal dispersion coefficient and the new equations proposed in this study were included in the advective dispersion equation to predict the suspended sediment concentrations at three sites in the Humber Estuary sited along the northeast coast of England. The average percentage errors between the predicted- and measured-field data for the proposed new dispersion equations were less than those obtained using the previously documented equations. PMID:11996348

Kashefipour, Seyed M; Falconer, Roger A



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



Alpha Testing Escape from Diab  

Technology Transfer Automated Retrieval System (TEKTRAN)

Alpha testing was conducted of sessions 2 and 3 from Diab to assess whether the activities worked as expected, and whether children in the target ages enjoyed it. Data include both RA observations of child performance while playing the games and cognitive interview responses from the players after t...


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.



Double-smoothing for Varying Coefficient Models  

PubMed Central

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 problem of strong parametric assumptions with current practice of moderation analysis and provide a much broader class of models for complex moderation relationships. Local polynomial, especially local linear, methods are commonly used in estimating the varying coefficient models. Recently, a double-smoothing (DS) local linear method has been proposed for nonparametric regression models, with nice properties compared to local linear and local cubic methods. In this paper, we generalize DS to varying coefficient models, and show that it holds similar advantages over local linear and local cubic methods. PMID:22121327

Tang, Wan; Zuo, Guoxin; He, Hua



Quantization, holography, and the universal coefficient theorem  

NASA Astrophysics Data System (ADS)

I present a method of quantization using cohomology groups extended via coefficient groups of different types. This is possible according to the universal coefficient theorem. I also show that by using this method new features of quantum field theory not visible in the previous treatments emerge. The main argument is that several constructions considered as absolute until now may appear as relative, depending on individual choices of group structures needed to probe a topology. The universal coefficient theorem also gives information about how these structures, as measured by different choices of groups, relate to one another. This may result in the formulation of new dualities and a deeper understanding of the relation between quantum field theories and gravity.

Patrascu, Andrei T.



Quantization, Holography and the Universal Coefficient Theorem  

E-print Network

I present a method of quantization using cohomology groups extended via coefficient groups of different types. This is possible according to the Universal Coefficient Theorem (UCT). I also show that by using this method new features of quantum field theory not visible in the previous treatments emerge. The main argument is that several constructions considered as absolute until now may appear as relative, depending on individual choices of group structures needed to probe a topology. The universal coefficient theorem also gives information about how these structures as measured by different choices of groups, relate to each other. This may result in the formulation of new dualities and a deeper understanding of the relation between quantum field theories and gravity.

Andrei T. Patrascu



Diffusion coefficients in leaflets of bilayer membranes  

E-print Network

We study diffusion coefficients of liquid domains by explicitly taking into account the two-layered structure called leaflets of the bilayer membrane. In general, the velocity fields associated with each leaflet are different and the layers sliding past each other cause frictional coupling. We obtain analytical results of diffusion coefficients for a circular liquid domain in a leaflet, and quantitatively study their dependence on the inter-leaflet friction. We also show that the diffusion coefficients diverge in the absence of coupling between the bilayer and solvents, even when the inter-leaflet friction is taken into account. In order to corroborate our theory, the effect of the inter-leaflet friction on the correlated diffusion is examined.

Kazuhiko Seki; Saurabh Mogre; Shigeyuki Komura



Coexistence of {alpha}+{alpha}+n+n and {alpha}+t+t cluster structures in {sup 10}Be  

SciTech Connect

The coexistence of the {alpha}+{alpha}+n+n and {alpha}+t+t cluster structures in the excited states of {sup 10}Be has been discussed. In the previous analysis, all the low-lying states of {sup 10}Be were found to be well described by the motion of the two valence neutrons around two {alpha} clusters. However, the {alpha}+t+t cluster structure was found to coexist with the {alpha}+{alpha}+n+n structure around E{sub x}=15 MeV, close to the corresponding threshold. We have introduced a microscopic model to solve the coupling effect between these two configurations. The K=0 and K=1 states are generated from the {alpha}+t+t configurations due to the spin coupling of two triton clusters. The present case of {sup 10}Be is one of the few examples in which completely different configurations of triton-type ({alpha}+t+t three-center) and {alpha}-type ({alpha}+{alpha}+n+n two-center) clusters coexist in a single nucleus in the same energy region.

Itagaki, N. [Department of Physics, University of Tokyo, Hongo, 113-0033 Tokyo (Japan); Ito, M. [RIKEN Nishina Center, Wako, 351-0198 Saitama (Japan); Milin, M. [Department of Physics, University of Zagreb, HR-10000 Zagreb (Croatia); Hashimoto, T.; Ishiyama, H.; Miyatake, H. [Tokai Radioactive Ion Accelerator Complex, High Energy Accelerator Research Organization (KEK), Tokai, 319-1105 Ibaraki (Japan)



Alpha effect due to buoyancy instability of a magnetic layer  

E-print Network

A strong toroidal field can exist in form of a magnetic layer in the overshoot region below the solar convection zone. This motivates a more detailed study of the magnetic buoyancy instability with rotation. We calculate the alpha effect due to helical motions caused by a disintegrating magnetic layer in a rotating density-stratified system with angular velocity Omega making an angle theta with the vertical. We also study the dependence of the alpha effect on theta and the strength of the initial magnetic field. We carry out three-dimensional hydromagnetic simulations in Cartesian geometry. A turbulent EMF due to the correlations of the small scale velocity and magnetic field is generated. We use the test-field method to calculate the transport coefficients of the inhomogeneous turbulence produced by the layer. We show that the growth rate of the instability and the twist of the magnetic field vary monotonically with the ratio of thermal conductivity to magnetic diffusivity. The resulting alpha effect is inho...

Chatterjee, Piyali; Rheinhardt, Matthias; Brandenburg, Axel



Seebeck Coefficient Measured With Differential Heat Pulses  

NASA Technical Reports Server (NTRS)

Common experimental errors reduced because pulse technique suppresses drifts in thermoelectric measurements. Differential-heat-pulse apparatus measures Seebeck coefficient in semiconductors at temperatures up to 1,900 K. Sample heated to measuring temperature in furnace. Ends of sample then differentially heated a few degrees more by lamps. Differential temperature rise and consequent Seebeck voltage measured via thermocouple leads. Because pulse technique used, errors that often arise from long-term drifts in thermoelectric measurements suppressed. Apparatus works with temperature differences of only few degrees, further increasing accuracy of coefficients obtained.

Zoltan, L.; Wood, C.; Stapfer, G.



Absorption coefficient instrument for turbid natural waters  

NASA Technical Reports Server (NTRS)

The paper presents an instrument that directly measures multispectral absorption coefficient of turbid natural water. Attention is given to the design, which is shown to incorporate methods for the compensation of variation in the internal light source intensity, correction of the spectrally dependent nature of the optical elements, and correction for variation in the background light level. In addition, when used in conjunction with a spectrally matched total attenuation instrument, the spectrally dependent scattering coefficient can also be derived. Finally, it is reported that systematic errors associated with multiple scattering have been estimated using Monte Carlo techniques.

Friedman, E.; Cherdak, A.; Poole, L.; Houghton, W.



Virial expansion coefficients in the harmonic approximation  

NASA Astrophysics Data System (ADS)

The virial expansion method is applied within a harmonic approximation to an interacting N-body system of identical fermions. We compute the canonical partition functions for two and three particles to get the two lowest orders in the expansion. The energy spectrum is carefully interpolated to reproduce ground-state properties at low temperature and the noninteracting high-temperature limit of constant virial coefficients. This resembles the smearing of shell effects in finite systems with increasing temperature. Numerical results are discussed for the second and third virial coefficients as functions of dimension, temperature, interaction, and transition temperature between low- and high-energy limits.

Armstrong, J. R.; Zinner, N. T.; Fedorov, D. V.; Jensen, A. S.



Transport coefficients in Chiral Perturbation Theory  

E-print Network

We present recent results on the calculation of transport coefficients for a pion gas at zero chemical potential in Chiral Perturbation Theory using Linear Response Theory. More precisely, we show the behavior of DC conductivity and shear viscosity at low temperatures. To compute transport coefficients, the standard power counting of ChPT has to be modified. The effects derived from imposing unitarity are also analyzed. As physical applications in Relativistic Heavy Ion Collisions, we show the relation of the DC conductivity to soft-photon production and phenomenological effects related to a nonzero shear viscosity. In addition, our values for the shear viscosity to entropy ratio satisfy the KSS bound.

D. Fernandez-Fraile; A. Gomez Nicola



Diffusion and transport coefficients in synthetic opals  

SciTech Connect

Opals are structures composed of close-packed spheres in the size range of nano to micrometers. They are sintered to create small necks at the points of contact. We have solved the diffusion problem in such structures. The relation between the diffusion coefficient and the thermal and electrical conductivity is used to estimate the transport coefficients of opal structures as a function of the neck size and the mean free path of the carriers. The theory presented is also applicable to the diffusion problem in other periodic structures. (c) 2000 The American Physical Society.

Sofo, J. O. [Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica, (8400) Bariloche RN, (Argentina)] [Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica, (8400) Bariloche RN, (Argentina); Mahan, G. D. [Solid State Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6030 (United States) [Solid State Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6030 (United States); Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996-1200 (United States)



Aversive Situational Effects on Alpha Feedback Training  

ERIC Educational Resources Information Center

Anticipation of electric shock did not depress alpha activity in a feedback situation. Contrary to previous reports, a reduction in alpha activity is not a necessary consequence of apprehension or heightened arousal. (Author)

Orne, Martin T.; Paskeqitz, David A.



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



Association of actin with alpha crystallins  

NASA Technical Reports Server (NTRS)

The alpha crystallins are cytosolic proteins that co-localize and co-purify with actin-containing microfilaments. Affinity column chromatography employing both covalently-coupled actin or alpha crystallin was used to demonstrate specific and saturable binding of actin with alpha crystallin. This conclusion was confirmed by direct visualization of alpha aggregates bound to actin polymerized in vitro. The significance of this interaction in relation to the functional properties of these two polypeptides will be discussed.

Gopalakrishnan, S.; Boyle, D.; Takemoto, L.; Spooner, B. S. (Principal Investigator)



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



Osmotic Coefficients and Mean Activity Coefficients of Uni-univalent Electrolytes in Water at 25°C  

Microsoft Academic Search

This paper gives values for the osmotic coefficients and mean activity coefficients of uni-univalent electrolytes in aqueous solutions at 25 °C. The values are expressed on the molality or weight basis. The data available in the literature have been corrected to the presently accepted scales of atomic weights (1969) and temperature (IPST 1968) and, where necessary, to the absolute electrical

Walter J. Hamer; Yung-Chi Wu



Unfolding domains of recombinant fusion alpha alpha-tropomyosin.  

PubMed Central

The thermal unfolding of the coiled-coil alpha-helix of recombinant alpha alpha-tropomyosin from rat striated muscle containing an additional 80-residue peptide of influenza virus NS1 protein at the N-terminus (fusion-tropomyosin) was studied with circular dichroism and fluorescence techniques. Fusion-tropomyosin unfolded in four cooperative transitions: (1) a pretransition starting at 35 degrees C involving the middle of the molecule; (2) a major transition at 46 degrees C involving no more than 36% of the helix from the C-terminus; (3) a major transition at 56 degrees C involving about 46% of the helix from the N-terminus; and (4) a transition from the nonhelical fusion domain at about 70 degrees C. Rabbit skeletal muscle tropomyosin, which lacks the fusion peptide but has the same tropomyosin sequence, does not exhibit the 56 degrees C or 70 degrees C transition. The very stable fusion unfolding domain of fusion-tropomyosin, which appears in electron micrographs as a globular structural domain at one end of the tropomyosin rod, acts as a cross-link to stabilize the adjacent N-terminal domain. The least stable middle of the molecule, when unfolded, acts as a boundary to allow the independent unfolding of the C-terminal domain at 46 degrees C from the stabilized N-terminal unfolding domain at 56 degrees C. Thus, strong localized interchain interactions in coiled-coil molecules can increase the stability of neighboring domains. PMID:1303750

Ishii, Y.; Hitchcock-DeGregori, S.; Mabuchi, K.; Lehrer, S. S.



Analogs of alpha-conotoxin MII are selective for alpha6-containing nicotinic acetylcholine receptors.  


Neuronal nicotinic acetylcholine receptors (nAChRs) both mediate direct cholinergic synaptic transmission and modulate synaptic transmission by other neurotransmitters. Novel ligands are needed as probes to discriminate among structurally related nAChR subtypes. Alpha-conotoxin MII, a selective ligand that discriminates among a variety of nAChR subtypes, fails to discriminate well between some subtypes containing the closely related alpha3 and alpha6 subunits. Structure-function analysis of alpha-conotoxin MII was performed in an attempt to generate analogs with preference for alpha6-containing [alpha6(*) (asterisks indicate the possible presence of additional subunits)] nAChRs. Alanine substitution resulted in several analogs with decreased activity at alpha3(*) versus alpha6(*) nAChRs heterologously expressed in Xenopus laevis oocytes. From the initial analogs, a series of mutations with two alanine substitutions was synthesized. Substitution at His9 and Leu15 (MII[H9A;L15A]) resulted in a 29-fold lower IC(50) at alpha6beta4 versus alpha3beta4 nAChRs. The peptide had a 590-fold lower IC(50) for alpha6/alpha3beta2 versus alpha3beta2 and a 2020-fold lower IC(50) for alpha6/alpha3beta2beta3 versus alpha3beta2 nAChRs. MII[H9A;L15A] had little or no activity at alpha2beta2, alpha2beta4, alpha3beta4, alpha4beta2, alpha4beta4, and alpha7 nAChRs. Functional block by MII[H9A;L15A] of rat alpha6/alpha3beta2beta3 nAChRs (IC(50) = 2.4 nM) correlated well with the inhibition constant of MII[H9A;L15A] for [(125)I]alpha-conotoxin MII binding to putative alpha6beta2(*) nAChRs in mouse brain homogenates (K(i) = 3.3 nM). Thus, structure-function analysis of alpha-conotoxin MII enabled the creation of novel selective antagonists for discriminating among nAChRs containing alpha3 and alpha6 subunits. PMID:15044624

McIntosh, J Michael; Azam, Layla; Staheli, Sarah; Dowell, Cheryl; Lindstrom, Jon M; Kuryatov, Alexander; Garrett, James E; Marks, Michael J; Whiteaker, Paul



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



Determination of diffusion coefficient for unsaturated soils  

E-print Network

= parenrightexparenrightbtparenrighttpparenleftbtparenlefttpparenrightexparenrightex parenrightbt parenrighttp parenleftexparenleftexparenleftbt parenlefttp -+= 1 2 2 cos n n n n l xz l tAuu alpha (22) where, ( ) n n n zzz zA cos sin0 + -= and l zz e n n =cot where, u = sufction as fufnction of distance and time... Page VI REFINEMENT TO MITCHELL?S FORMULATION.................... 63 6.1 Introduction ............................................................................... 63 6.2 Refinement: n notequal 1 and n = m...

Sood, Eeshani



Time-dependent theory of alpha decay  

Microsoft Academic Search

Using Green's function techniques a time-dependent theory of ..cap alpha.. decay in the standard one-body model is developed. Formulas are obtained for the decay rate and ..cap alpha.. energy. These formulas are combined with experimental information to show that to a good approximation the initial ..cap alpha..-particle wave function vanishes on or near the nuclear surface.

Michael G. Fuda



Time-dependent theory of alpha decay  

SciTech Connect

Using Green's function techniques a time-dependent theory of ..cap alpha.. decay in the standard one-body model is developed. Formulas are obtained for the decay rate and ..cap alpha.. energy. These formulas are combined with experimental information to show that to a good approximation the initial ..cap alpha..-particle wave function vanishes on or near the nuclear surface.

Fuda, M.G.



Alpha particle condensation and nuclear rainbow scattering  

E-print Network

It is shown that a dilute property of an $\\alpha$ particle condensate can be seen in the Airy structure of nuclear rainbow and prerainbow scattering. The dilute property of the Hoyle state of $^{12}$C with a developed $\\alpha$ cluster structure is discussed by studying refractive $^3$He+$^{12}$C and $\\alpha$+$^{12}$C scattering.

S Ohkubo; Y Hirabayashi



Recent Results on the CKM Angle Alpha  

SciTech Connect

The method to measure the CKM angle {alpha} and the modes sensitive to it are discussed. It is shown that the B {yields} {rho}{rho} decays provide the most stringent constraint on {alpha}, which is found to be {alpha} = 96{sup o} {+-} 10{sup o}(stat) {+-} 4{sup o}(syst){+-} 13{sup o}(penguin).

Mihalyi, A.; /Wisconsin U., Madison



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.



Refinement of the $n-\\alpha$ and $p-\\alpha$ fish-bone potential  

E-print Network

The fishbone potential of composite particles simulates the Pauli effect by nonlocal terms. We determine the $n-\\alpha$ and $p-\\alpha$ fish-bone potential by simultaneously fitting to the experimental phase shifts. We found that with a double Gaussian parametrization of the local potential can describe the $n-\\alpha$ and $p-\\alpha$ phase shifts for all partial waves.

Smith, E; Papp, Z



Pressure viscosity coefficient of vegetable oils  

Technology Transfer Automated Retrieval System (TEKTRAN)

The elastohydrodynamic (EHD) pressure viscosity coefficient (PVC) of ten vegetable oils from commodity and new crops, and two petroleum-based oils, polyalphaolefin (PAO) and hexadecane, were investigated. PVC was measured using three different methods: the So and Klaus (S-K) procedure from oil visco...


Apparatus Measures Seebeck Coefficient And Resistivity  

NASA Technical Reports Server (NTRS)

Electrical measurements made by four point probes, two of which double as temperature probes. Laboratory apparatus measures both Seebeck coefficients and electrical resistivities of candidate thermoelectric materials at temperatures from ambient to 1,300 K. Apparatus makes possible to take both measurements alternately and in rapid succession during same heating cycle, thereby reducing distortion.

Zoltan, Leslie D.; Wood, Charles; Fleurial, Jean-Pierre; Liu, Yixin



Computer programs for the concordance correlation coefficient.  


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




Technology Transfer Automated Retrieval System (TEKTRAN)

Phosphorus (P) release to runoff varies widely for different land-applied organic-P sources even when applied at equivalent total P rates. To address this variability, some P site indices include tabulated P source coefficients (PSCs) for differential weighting of applied P materials based on their ...


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



Experimental Influence Coefficients and Vibration Modes  

NASA Technical Reports Server (NTRS)

Test results are presented for both symmetrical and antisymmetrical static loading of a wing model mounted on a three-point support system. The first six free-free vibration modes were determined experimentally. A comparison is made of the symmetrical nodal patterns and frequencies with the symmetrical nodal patterns and frequencies calculated from the experimental influence coefficients.

Weidman, Deene J.; Kordes, Eldon E.



Problems on Divisibility of Binomial Coefficients  

ERIC Educational Resources Information Center

Twelve unusual problems involving divisibility of the binomial coefficients are represented in this article. The problems are listed in "The Problems" section. All twelve problems have short solutions which are listed in "The Solutions" section. These problems could be assigned to students in any course in which the binomial theorem and Pascal's…

Osler, Thomas J.; Smoak, James



The Evolution of Pearson's Correlation Coefficient  

ERIC Educational Resources Information Center

This article describes an activity for developing the notion of association between two quantitative variables. By exploring a collection of scatter plots, the authors propose a nonstandard "intuitive" measure of association; and by examining properties of this measure, they develop the more standard measure, Pearson's Correlation Coefficient. The…

Kader, Gary D.; Franklin, Christine A.



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



Calculated Ångströim's Turbidity Coefficients for Fairbanks, Alaska  

Microsoft Academic Search

Ångströim's turbidity coefficient, [bgr], was determined from measurements of direct normal solar irradiance (broadband) at Fairbanks, Alaska (latitude, 64.82). The frequency distribution and seasonal changes of derived values were similar to those reported for rural sites in other parts of the world, whereas magnitudes were at the lower end of the reported range. The method was sensitive enough to detect

John D. Fox



Textbook Neglect of the Constant Coefficient  

ERIC Educational Resources Information Center

The authors argue that the textbook treatments of the constant term in regression analysis vary extensively and are often neglectful, incomplete, or even incorrect. Given the potential importance of the constant coefficient in theoretical and applied work, they develop the factors biasing the estimation of the constant term to support the argument…

Allen, Ralph C.; Stone, Jack H.



Phosphorus Availability Coefficients from Various Organic Sources  

Technology Transfer Automated Retrieval System (TEKTRAN)

The objectives of this study were to determine Phosphorus Availability Coefficients (PACs) for a variety of organic phosphorus (P) sources, and to examine the relationship between PACs measured in simulated rainfall runoff and alternative soil incubations. PAC is an important parameter in the P-Ind...


Fastening Parts Having Mismatched Thermal Coefficients  

NASA Technical Reports Server (NTRS)

Fastener eliminates thermal stresses and maintains snug fit. Conicalhead bolt and metal washer main components of fastener that keeps constant tension on carbon/carbon parts regardless of thermal stress. Fastener used in cases where fastened parts have unmatched thermalexpansion coefficients. Does not become looser or tighter as conventional bolts and nuts or rivets do at elevated temperatures.

Jackson, L. R.; Davis, R. C.; Taylor, A. H.; Mcwithey, R. R.; Blosser, M. L.



Direct measurement of piezoelectric shear coefficient  

NASA Astrophysics Data System (ADS)

Piezoelectric materials exhibit electromechanical coupling which has led to their widespread application for sensors, actuators, and energy harvesters. These materials possess anisotropic behavior with the shear coefficient, and have the largest electromechanical coupling coefficient. However, the shear mode is difficult to measure with existing techniques and thus has not been fully capitalized upon in recent devices. Better understanding of the full shear response with respect to the driving electric field would significantly help the design of optimized piezoelectric shear devices. Here, a simple and low cost direct measurement method based on digital image correlation is developed to characterize the shear response of piezoelectric materials and its nonlinear behavior as a function of external field. The piezoelectric shear coefficient (d15) of a commercial shear plate actuator is investigated in both bipolar and unipolar electric fields. Two different nonlinearities and hysteresis behaviors of the actuators were observed, and the relation between the driving field amplitude and the corresponding d15 coefficient is determined. Moreover, the measured transverse displacement of the plate actuator in simple shear condition is validated through a laser interferometry technique.

Malakooti, Mohammad H.; Sodano, Henry A.



Static coefficient test method and apparatus  

NASA Technical Reports Server (NTRS)

The static coefficient of friction between contacting surfaces of a plurality of bodies is determined by applying a load to the bodies in a direction normal to the contacting surfaces. Opposite ends of a flexible filament are connected to a load cell and the first of the bodies. A motor continuously moves the second of the bodies away from the load cell at constant velocity at right angles to the force of the normal load so that the first body moves intermittently relative to the second body across a contact surface between them. The load on the surfaces, the nature of the surfaces, and the speed of the first body relative to the load cell are such that the filament is alternately and cyclically tensioned and relaxed as the movement occurs. The maximum tension occurs at the incipient stages of movement of the first body relative to the second body. The load cell derives a series of measurements which are coupled to an x-y recorder, from which the maximum forces of the filament are determined to enable the static coefficient of friction to be determined. From the maximum forces and the normal force, the coefficient is determined. For determining coefficients of friction where there are large compression loads, the normal load is applied with a calibrated compression spring that is deflected by a predetermined amount determined by a spring load vs. deflection calibration curve.

Haehner, C. L.; Tarpley, J. L. (inventors)



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



Remec test with vanishing leading array coefficients  

Microsoft Academic Search

Remec's algorithm for finding breakaway points on the root locus suffers from a serious limitation when the first column entry of the first row of any s' group of the Remec array vanishes. In this paper, a remedy for such situations is proposed by rearranging the coefficients of the row in which a zero entry has occurred in the first




Transpiration coefficients for three Great Basin shrubs  

Microsoft Academic Search

Transpiration by desert phreatophytes is poorly understood, and the few existing data are difficult to extrapolate spatially. This study developed transpiration coefficients (Kc) for Atriplex lentiformis ssp.torreyi , Chrysothamnus nauseosus and Sarcobatus vermiculatus to estimate transpiration using vegetation cover measurements. The Kc were developed from stomatal conductance, reference evapotranspiration (ETr), and modeled leaf area index (LAI). Transpiration estimates using the

Aaron L. Steinwand; Robert F. Harrington; David P. Groeneveld



Efficient synthesis of serically constrained smmetrically alpha,alpha-disubstituted alpha-amino acids under operationally convenient conditions.  


Homologation of the nucleophilic glycine equivalent Ni-Gly-PABP [Ni(II) complex of glycine Schiff base with 2-[N-(alpha-picolyl)amino]benzophenone (PABP)] 2 via alkyl halide alkylations and Michael addition reactions was systematically studied as a general method for preparing symmetrically alpha,alpha-disubstituted alpha-amino acids (sym-alpha,alpha-AA). The dialkylation reactions are conducted under operationally convenient conditions without recourse to inert atmosphere, dried solvents, and low temperatures, thus enjoying key advantages of the experimental simplicity and attractive cost structure. The method has been shown to be particularly successful for the dialkylation of complex 2 with activated and nonactivated alkyl halides, including propargyl derivatives, affording a generalized and practical access to the corresponding sym-alpha,alpha-AA. This study has also shown some limitation of the method, as it cannot be extended to alpha- or beta-branched alkyl halides or Michael acceptors to be used for the dialkylation of glycine equivalent 2. High chemical yields of the dialkylated products, combined with the simplicity of the experimental procedure, render this method worth immediate use for multigram scale preparation of the sym-alpha,alpha-AA. PMID:12895052

Ellis, Trevor K; Martin, Collin H; Tsai, Gary M; Ueki, Hisanori; Soloshonok, Vadim A



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: [University of Warwick, Department of Statistics (United Kingdom)



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



Layer coefficients for NHDOT pavement materials  

NASA Astrophysics Data System (ADS)

In 1992, the New Hampshire Department of Transportation (NHDOT) experimented with the use of reclaimed asphalt concrete as a base course material, identified by NHDOT as reclaimed stabilized base (RSB). The RSB and a control test section were placed on Interstate 93 between exits 18 and 19. The RSB test section was designed to the same structural number (SN) as the control. To evaluate the structural capacity of these test sections, the U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) conducted deflection tests using a Dynatest 8000 falling weight deflectometer (FWD). Preliminary analysis of the results by NHDOT personnel showed higher deflection in the reclaimed asphalt concrete test sections. The explanation was that the layer coefficient used for the RSB layer in the design was probably incorrect. A total of 10 test sections constituting the base course materials used by NHDOT were built near Bow, New Hampshire. CRREL evaluated and estimated the layer coefficients of the base course materials. The test program was developed to characterize the material in more than one way. Tests were conducted with the heavy weight deflectometer (HWD), dynamic cone penetrometer (DCP) and the Clegg hammer. In situ California bearing ratio (CBR) tests were also conducted. The deflection from the HWD were used with the WESDEF back calculation program to determine the layer moduli. The moduli were than used with the AASHTO Design Guide to calculate the layer coefficients. The layer coefficients were also determined with the method proposed by Rohde. The CBR values from the Clegg hammer, in situ CBR and DCP tests were also used in the relationships in the HDM model to determine the layer coefficients.

Janoo, Vincent C.



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



Possible bioactive conformations of alpha-melanotropin.  


By comparing the results of energy calculation for alpha-MSH and its semirigid analogues Ac-[ Cys4 , Cys10 ]-alpha- MSH4 -10-NH2, Ac-[ Cys4 , Cys10 ]-alpha- MSH4 -13-NH2, and [ Cys4 - Cys10 ]-alpha-MSH, a detailed description of two possible bioactive conformations for the 'specific' central site of alpha- MSH6 -9 is proposed representing variants of chain-reversal structure. A possible explanation of the rise in melanotropic activity of the latter two semirigid analogues is presented. PMID:6723968

Nikiforovich, G V; Rozenblit, S A; Shenderovich, M D; Chipens, G I



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)




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: [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark)



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

NASA Technical Reports Server (NTRS)

It is pointed out that the intensity of the Lyman-alpha emission is a good indicator of the principal aeronomical processes on the major planets. The high-resolution ultraviolet spectrometer aboard the Orbiting Astronomical Observatory Copernicus was used in 1980 April and May to detect the Jovian Lyman-alpha emission by spectroscopically discriminating it from other Doppler shifted Lyman-alpha emissions such as those of the geocorona, and the interplanetary medium. Taking into consideration the reported emission data, it appears that an unusually large energy input due to the particle precipitation in the auroral region must have been responsible for the large observed Lyman-alpha intensity during the Voyager encounter. At most other times, the observed Jovian Lyman-alpha intensity can be explained, within the range of statistical uncertainty, by a model that takes into consideration the solar EUV flux, the solar Lyman-alpha flux, the high exospheric temperature, and the eddy diffusion coefficient without energy input from the auroral sources.

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



The Assessment of Reliability Under Range Restriction: A Comparison of [Alpha], [Omega], and Test-Retest Reliability for Dichotomous Data  

ERIC Educational Resources Information Center

Though much research and attention has been directed at assessing the correlation coefficient under range restriction, the assessment of reliability under range restriction has been largely ignored. This article uses item response theory to simulate dichotomous item-level data to assess the robustness of KR-20 ([alpha]), [omega], and test-retest…

Fife, Dustin A.; Mendoza, Jorge L.; Terry, Robert



A Statistical Analysis of YORP Coefficients  

NASA Astrophysics Data System (ADS)

The YORP (Yarkovsky-O'Keefe-Radzievskii-Paddack) effect is theorized to be a major factor in the evolution of small asteroids (<10 km) in the near-Earth and main belt populations. YORP torques, which originate from absorbed sunlight and subsequent thermal radiation, causes secular changes in an asteroid's spin rate and spin vector orientation (e.g. Rubincam, Journal of Geophysical Research, 1995). This in turn controls the magnitude and direction of the Yarkovsky effect, which causes a drift in an asteroid's heliocentric semi-major axis (Vokrouhlicky and Farinella, Nature, 2000). YORP is also thought to be responsible for the creation of multiple asteroid systems and asteroid pairs through the process of rotational fission (Pravec et al, Nature, 2010). Despite the fact that the YORP effect has been measured on several asteroids (e.g. Taylor et al, Science, 2007 and Kaasalainen et al, Nature, 2007), it has proven very difficult to predict the effect accurately from a shape model due to the sensitivity of the YORP coefficients to shape changes (Statler, Icarus, 2009). This has been especially troublesome for Itokawa, for which a very detailed shape model is available (Scheeres et al, Icarus 2007; Breiter et al, Astronomy & Astrophysics, 2009). In this study, we compute the YORP coefficients for a number asteroids with detailed shape models available on the PDS-SBN. We then statistically perturb the asteroid shapes at the same resolution, creating a family of YORP coefficients for each shape. Next, we analyze the change in YORP coefficients between a shape model of accuracy obtainable from radar with one including small-scale topography on the surface as was observed on Itokawa. The combination of these families of coefficients will effectively give error bars on our knowledge of the YORP coefficients given a shape model of some accuracy. Finally, we discuss the statistical effect of boulder and craters, and the modification of these results due to recent studies on thermal beaming (Rozitis and Green, Mon. Not. R. Astron. Soc., 2012) and "tangential" YORP (Golubov and Krugly, The Astrophysical Journal Letters, 2012).

McMahon, Jay W.; Scheeres, D.



Transport Coefficients and nPI Methods  

E-print Network

Transport coefficients can be obtained from 2-point correlators using the Kubo formulae. It has been shown that the full leading order result for electrical conductivity and (QCD) shear viscosity is contained in the re-summed 2-point function that is obtained from the 3-loop 3PI effective action. The theory produces all leading order contributions without the necessity for power counting, and in this sense it provides a natural framework for the calculation and suggests that one can calculate the next-to-leading contribution to transport coefficients from the 4-loop 4PI effective action. The integral equations have been derived for shear viscosity for a scalar theory with cubic and quartic interactions, with a non-vanishing field expectation value. We review these results, and explain how the calculation could be done at higher orders.

M. E. Carrington



Minior Actinide Doppler Coefficient Measurement Assessment  

SciTech Connect

The "Minor Actinide Doppler Coefficient Measurement Assessment" was a Department of Energy (DOE) U-NERI funded project intended to assess the viability of using either the FLATTOP or the COMET critical assembly to measure high temperature Doppler coefficients. The goal of the project was to calculate using the MCNP5 code the gram amounts of Np-237, Pu-238, Pu-239, Pu-241, AM-241, AM-242m, Am-243, and CM-244 needed to produce a 1E-5 in reactivity for a change in operating temperature 800C to 1000C. After determining the viability of using the assemblies and calculating the amounts of each actinide an experiment will be designed to verify the calculated results. The calculations and any doncuted experiments are designed to support the Advanced Fuel Cycle Initiative in conducting safety analysis of advanced fast reactor or acceoerator-driven transmutation systems with fuel containing high minor actinide content.

Nolan E. Hertel; Dwayne Blaylock



Manning's roughness coefficient for Illinois streams  

USGS Publications Warehouse

Manning's roughness coefficients for 43 natural and constructed streams in Illinois are reported and displayed on a U.S. Geological Survey Web site. At a majority of the sites, discharge and stage were measured, and corresponding Manning's coefficients—the n-values—were determined at more than one river discharge. The n-values discussed in this report are computed from data representing the stream reach studied and, therefore, are reachwise values. Presentation of the resulting n-values takes a visual-comparison approach similar to the previously published Barnes report (1967), in which photographs of channel conditions, description of the site, and the resulting n-values are organized for each site. The Web site where the data can be accessed and are displayed is at URL

Soong, David T.; Prater, Crystal D.; Halfar, Teresa M.; Wobig, Loren A.



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



Empirical determination of the electroabsorption coefficient in semiconductors  

Microsoft Academic Search

On the basis of the integral formula of Rees relating the electroabsorption coefficient to the zero-field absorption coefficient, scaling rules for the electroabsorption coefficient are obtained. These rules allow the spectral and field dependence of the electroabsorption coefficient near the fundamental band edge to be obtained. They also allow the identification of trends, thus impacting on the choice of materials

I. Galbraith; B. Ryvkin



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.



Discharge coefficients for miniature fuel injectors  

NASA Astrophysics Data System (ADS)

'Hydraulic flip' is the mechanism by which vapor-forced axisymmetric separation of fluid from the internal boundary of injector walls occurs. With the development of small, low-thrust spacecraft engines employing miniature fuel injectors, knowledge regarding the performance of sharp-edged devices operating in the preflip and postflip phases becomes critical. Attention is given to the results of an experimental investigation of the discharge coefficients associated with a range of sharp-edged injectors having submillimeter-bore diameters.

Fox, T. A.; Stark, J.


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.


Extraction of the coefficient of giant magnetoresistance  

SciTech Connect

Element specific magnetic hysteresis (ESMH) loops have been used in conjunction with measured magnetoresistance curves to extract the coefficient of giant magnetoresistance (GMR), which is the maximum achievable value of the GMR independent of magnetic domain effects and incomplete moment alignment effects, for sputtered Fe/Cu/Co sandwiches on silicon substrates. Using the ESMH loops to calculate GMR curves, comparison with the measured GMR curves shows that the magnetization reversal process is best described by multidomain Ising behavior.

Idzerda, Y.U. (Naval Research Laboratory, Washington, DC 20375 (United States)); Chen, C. (AT T Bell Laboratories, 600 Mountain Avenue, Murray Hill, New Jersey 07974 (United States)); Cheng, S. (Naval Surface Warfare Center, Silver Spring, Maryland 20910 (United States)); Vavra, W.; Prinz, G.A. (Naval Research Laboratory, Washington, DC 20375 (United States)); Meigs, G.; Lin, H. (AT T Bell Laboratories, 600 Mountain Avenue, Murray Hill, New Jersey 07974 (United States)); Ho, G.H. (Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States))



Discharge Coefficients for Axisymmetric Supersonic Nozzles  

NASA Technical Reports Server (NTRS)

Computational Fluid Dynamics (CFD) analysis was used to compute effective nozzle discharge coefficients for subscale sharp-edged converging/diverging nozzles, with a variety of convergence half-angles, motor operating conditions, and two propellants with different ballistics. Convergence half-angles ranged from 0 to 80 deg. Analysis was conducted at total temperatures from 2946K (5303R) to 3346K (6023R) and over total pressures ranged from 2.72 MPa (395 psia) to 20.68 MPa (3000 psia). Area ratios (A(sub e)/A*) ranged from 7.43 to 9.39. Ratio of specific heats (gamma) ranged from 1.13 to 1.18. Throat and exit Reynolds numbers were calculated to be 8.26 x 10(exp 5) and 5.51 x 10(exp 5), respectively. Present results of nozzle discharge coefficients are reported and correlated as a function of nozzle convergence half-angle (theta(sub c)) and area ratios (A(sub e)/A*) for a constant divergence half-angle (theta(sub d)) of 15 deg. Computed discharge coefficients ranged from 0.88 to 0.97. They are compared with theory and experimental data available in literature. Available turbulence models with respect to grid refinements and heat transfer are discussed.

Ahmad, Rashid A.; McCool, A. A. (Technical Monitor)



On the analysis of the H Lyman-alpha dayglow of Jupiter, Saturn and Uranus  

NASA Astrophysics Data System (ADS)

A new radiative transfer model, particularly well adapted to calculations in inhomogeneous atmospheres, has been applied, during the last four years, to analyze new and older Lyman-alpha airglow data from three giant planets. We review all the results obtained so far. Several features which were not accounted for by using the previous transfer codes were satisfactorily simulated, using essentially the scattering of the solar and the interplanetary Lyman-alpha lines by hydrogen in the upper atmospheres. The search for a good fit both in intensity and in shape of the limb to limb data, and/or of the line profiles, provided constraints on the dynamics of the atmospheres, through the estimate of either the eddy diffusion coefficient, the total H column density, or of the possibility of some nonthermal turbulence processes at high altitude. Consequently, the need for an 'electroglow' process for the Lyman-alpha emission was considerably reduced and may be dismissed in the majority of cases.

Emerich, C.; Ben Jaffel, L.; Prange, R.



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



Recoil-alpha-fission and recoil-alpha-alpha-fission events observed in the reaction Ca-48 + Am-243  

E-print Network

Products of the fusion-evaporation reaction Ca-48 + Am-243 were studied with the TASISpec set-up at the gas-filled separator TASCA at the GSI Helmholtzzentrum f\\"ur Schwerionenforschung. Amongst the detected thirty correlated alpha-decay chains associated with the production of element Z=115, two recoil-alpha-fission and five recoil-alpha-alpha-fission events were observed. The latter are similar to four such events reported from experiments performed at the Dubna gas-filled separator. Contrary to their interpretation, we propose an alternative view, namely to assign eight of these eleven decay chains of recoil-alpha(-alpha)-fission type to start from the 3n-evaporation channel 115-288. The other three decay chains remain viable candidates for the 2n-evaporation channel 115-289.

Forsberg, U; Andersson, L -L; Di Nitto, A; Düllmann, Ch E; Gates, J M; Golubev, P; Gregorich, K E; Gross, C J; Herzberg, R -D; Hessberger, F P; Khuyagbaatar, J; Kratz, J V; Rykaczewski, K; Sarmiento, L G; Schädel, M; Yakushev, A; Åberg, S; Ackermann, D; Block, M; Brand, H; Carlsson, B G; Cox, D; Derkx, X; Dobaczewski, J; Eberhardt, K; Even, J; Fahlander, C; Gerl, J; Jäger, E; Kindler, B; Krier, J; Kojouharov, I; Kurz, N; Lommel, B; Mistry, A; Mokry, C; Nazarewicz, W; Nitsche, H; Omtvedt, J P; Papadakis, P; Ragnarsson, I; Runke, J; Schaffner, H; Schausten, B; Shi, Y; Thörle-Pospiech, P; Torres, T; Traut, T; Trautmann, N; Türler, A; Ward, A; Ward, D E; Wiehl, N



Recoil-alpha-fission and recoil-alpha-alpha-fission events observed in the reaction Ca-48 + Am-243  

E-print Network

Products of the fusion-evaporation reaction Ca-48 + Am-243 were studied with the TASISpec set-up at the gas-filled separator TASCA at the GSI Helmholtzzentrum f\\"ur Schwerionenforschung. Amongst the detected thirty correlated alpha-decay chains associated with the production of element Z=115, two recoil-alpha-fission and five recoil-alpha-alpha-fission events were observed. The latter are similar to four such events reported from experiments performed at the Dubna gas-filled separator. Contrary to their interpretation, we propose an alternative view, namely to assign eight of these eleven decay chains of recoil-alpha(-alpha)-fission type to start from the 3n-evaporation channel 115-288. The other three decay chains remain viable candidates for the 2n-evaporation channel 115-289.

U. Forsberg; D. Rudolph; L. -L. Andersson; A. Di Nitto; Ch. E. Düllmann; J. M. Gates; P. Golubev; K. E. Gregorich; C. J. Gross; R. -D. Herzberg; F. P. Hessberger; J. Khuyagbaatar; J. V. Kratz; K. Rykaczewski; L. G. Sarmiento; M. Schädel; A. Yakushev; S. Åberg; D. Ackermann; M. Block; H. Brand; B. G. Carlsson; D. Cox; X. Derkx; J. Dobaczewski; K. Eberhardt; J. Even; C. Fahlander; J. Gerl; E. Jäger; B. Kindler; J. Krier; I. Kojouharov; N. Kurz; B. Lommel; A. Mistry; C. Mokry; W. Nazarewicz; H. Nitsche; J. P. Omtvedt; P. Papadakis; I. Ragnarsson; J. Runke; H. Schaffner; B. Schausten; Y. Shi; P. Thörle-Pospiech; T. Torres; T. Traut; N. Trautmann; A. Türler; A. Ward; D. E. Ward; N. Wiehl



Sorption of humic acids and alpha-endosulfan by clay minerals.  


Sorption of alpha-endosulfan by kaolinite and montmorillonite alone and in the presence of sorbed and dissolved humic acid (HA) was investigated (pH 8 and 25 degrees C). Three types of HA, Elliot soil HA (EHA), Peat HA (PHA), and Summit Hill HA (SHHA), were used to represent typical humic substances found in soils. For sorption of HA by either mineral, Freundlich sorption coefficient (K(f)) values appeared to decrease in the order of EHA > PHA > SHHA, which followed increasing polarity (expressed as the O/C atomic ratio) and decreasing percent-carbon content. For both clays, sorption of alpha-endosulfan by the HA mineral complex was greater than for sorption by the clay alone. Sorption of alpha-endosulfan by the HA mineral complexes followed the same order as the K(f) of the HAs (EHA > PHA > SHHA). Based on the amount of HA adsorbed by each mineral, organic carbon partition coefficients (K(oc)) were determined for sorption of alpha-endosulfan by two of the HA mineral complexes. The value of K(oc) for alpha-endosulfan sorption was greater for kaolinite EHA than kaolinite SHHA. However, the opposite trend was found with the montmorillonite HA complexes. Montmorillonite appeared to sorb alpha-endosulfan and/or HA with higher affinity than kaolinite, which likely is due to its 2:1 layer structure and higher surface area. Sorption of endosulfan diol, a hydrolysis product, by the minerals was much less than the parent pesticide. PMID:16494219

Hengpraprom, Sarunya; Lee, Cindy M; Coates, John T



High gas flow alpha detector  


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.



High gas flow alpha detector  


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.

Bolton, Richard D. (Los Alamos, NM); Bounds, John A. (Los Alamos, NM); Rawool-Sullivan, Mohini W. (Los Alamos, NM)



Targeted alpha therapy for cancer  

NASA Astrophysics Data System (ADS)

Targeted alpha therapy (TAT) offers the potential to inhibit the growth of micrometastases by selectively killing isolated and preangiogenic clusters of cancer cells. The practicality and efficacy of TAT is tested by in vitro and in vivo studies in melanoma, leukaemia, colorectal, breast and prostate cancers, and by a phase 1 trial of intralesional TAT for melanoma. The alpha-emitting radioisotope used is Bi-213, which is eluted from the Ac-225 generator and chelated to a cancer specific monoclonal antibody (mab) or protein (e.g. plasminogen activator inhibitor-2 PAI2) to form the alpha-conjugate (AC). Stable alpha-ACs have been produced which have been tested for specificity and cytotoxicity in vitro against melanoma (9.2.27 mab), leukaemia (WM60), colorectal (C30.6), breast (PAI2, herceptin), ovarian (PAI2, herceptin, C595), prostate (PAI2, J591) and pancreatic (PAI2, C595) cancers. Subcutaneous inoculation of 1-1.5 million human cancer cells into the flanks of nude mice causes tumours to grow in all mice. Tumour growth is compared for untreated controls, nonspecific AC and specific AC, for local (subcutaneous) and systemic (tail vein or intraperitoneal) injection models. The 213Bi-9.2.27 AC is injected into secondary skin melanomas in stage 4 patients in a dose escalation study to determine the effective tolerance dose, and to measure kinematics to obtain the equivalent dose to organs. In vitro studies show that TAT is one to two orders of magnitude more cytotoxic to targeted cells than non-specific ACs, specific beta emitting conjugates or free isotopes. In vivo local TAT at 2 days post-inoculation completely prevents tumour formation for all cancers tested so far. Intra-lesional TAT can completely regress advanced sc melanoma but is less successful for breast and prostate cancers. Systemic TAT inhibits the growth of sc melanoma xenografts and gives almost complete control of breast and prostate cancer tumour growth. Intralesional doses up to 450 µCi in human patients are effective in regressing melanomas, with no concomitant complications. These results point to the application of local and systemic TAT in the management of secondary cancer. Results of the phase 1 clinical trial of TAT of subcutaneous, secondary melanoma indicate proof of the principle that TAT can make tumours in patients regress.

Allen, Barry J.; Raja, Chand; Rizvi, Syed; Li, Yong; Tsui, Wendy; Zhang, David; Song, Emma; Qu, Chang Fa; Kearsley, John; Graham, Peter; Thompson, John



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



Concomitant dehydration mechanisms in single crystals of alpha,alpha-trehalose.  


The dehydration behaviour of alpha,alpha-trehalose (alpha-D-glucopyranosyl alpha-D-glucopyranoside) dihydrate single crystals is investigated by thermomicroscopy, Raman microscopy, and differential scanning calorimetry. The results show at a given stage the simultaneous presence of two polymorphic forms, amorphous material, and movement of a fluid phase. The study also underlines that the characterization of the average phase by conventional XRPD and DSC techniques is not sufficient to describe the dehydration mechanisms of alpha,alpha-trehalose particles. Moreover, it confirms that the dehydration behaviour is mainly driven by heterogeneities and the rate of water loss. PMID:19875105

Dupray, Valérie; Berton, Benjamin; Ossart, Stephen; Atmani, Hassan; Petit, Marie-Noëlle; Coquerel, Gérard



{alpha} decay of {sup 105}Te  

SciTech Connect

The {alpha} decay of the neutron-deficient nuclide {sup 105}Te was observed. The {sup 50}Cr({sup 58}Ni,3n) reaction was used to produce {sup 105}Te nuclei. The {sup 105}Te residues were selected with the Argonne Fragment Mass Analyzer and implanted into a double-sided Si strip detector where their subsequent {alpha} decay was detected. An {alpha}-decay Q value of Q{sub {alpha}}=4900(50) keV and a half life of T{sub 1/2}=0.70(-0.17+0.25){mu}s were measured for {sup 105}Te and a reduced {alpha}-decay width of W{sub {alpha}}=3.3(-1.7+2.1) was deduced. The decay properties of {sup 105}Te are compared with those of heavier Te isotopes and theoretical predictions.

Seweryniak, D.; Davids, C.N.; Gros, S.; Khoo, T.L.; Peterson, D.; Robinson, A.; Zhu, S. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Starosta, K.; Vaman, C. [National Superconducting Cyclotron Laboratory, East Lansing, Michigan 48824 (United States); Hecht, A.A.; Hoteling, N.; Walters, W.B. [University of Maryland, College Park, Maryland 20742 (United States); Lagergren, K.; Woods, P.J. [Department of Physics, Florida State University, Tallahassee, Florida 32306 (United States); Lotay, G. [University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom)



Alpha Subunit Position and GABA Receptor Function  

NSDL National Science Digital Library

GABAA (γ-aminobutyric acid type A) receptors are ligand-gated ion channels composed of five subunits, generally two &alpha;s, two βs, and a γ2. Recent research in which sets of subunits containing &alpha;1 or &alpha;6 subunits were artificially linked has revealed the importance of subunit position in determining GABAA receptor function. Sensitivity to benzodiazepines depended on juxtaposition of an &alpha;1 subunit with the γ2 subunit, whereas sensitivity to furosemide depended only on the presence of an &alpha;6 subunit and not on its specific location. The major utility of the linked subunit approach is to provide a mechanism for discovering the functional signatures of defined subunit arrangements, and thus a route to identifying such arrangements in vivo.

David R. Burt (University of Maryland School of Medicine;Department of Pharmacology REV)



A more efficient enzyme-linked immunosorbent assay for measurement of alpha-synuclein in cerebrospinal fluid.  


We describe a modification of a previously described assay for the quantification of alpha-synuclein in naive cerebrospinal fluid, which allows for a more efficient quantification of alpha-synuclein. Detection limit of the assay is 3.8 ng/ml and the assay is linear until 300 ng/ml. Inter-assay and intra-assay coefficients of variation are below 15% in a wide range of concentrations. Mean recovery of the assay is 94%. The 95% upper limit of the reference range (p95) in a group of neurological controls above the age of 45 years is 62 ng/ml. This assay can be routinely applied for quantification of alpha-synuclein in cerebrospinal fluid, but not in serum, and this may serve as a possible biomarker for alpha-synucleinopathies such as Parkinson's disease and multiple system atrophy. PMID:17976734

van Geel, Wieneke J A; Abdo, W Farid; Melis, René; Williams, Sonja; Bloem, Bastiaan R; Verbeek, Marcel M



Local Varying-Alpha Theories  

E-print Network

In a recent paper we demonstrated how the simplest model for varying alpha may be interpreted as the effect of a dielectric material, generalized to be consistent with Lorentz invariance. Unlike normal dielectrics, such a medium cannot change the speed of light, and its dynamics obey a Klein-Gordon equation. This work immediately suggests an extension of the standard theory, even if we require compliance with Lorentz invariance. Instead of a wave equation, the dynamics may satisfy a local algebraic relation involving the permittivity and the properties of the electromagnetic field, in analogy with more conventional dielectric (but still preserving Lorentz invariance). We develop the formalism for such theories and investigate some phenomenological implications. The problem of the divergence of the classical self-energy can be solved, or at least softened, in this framework. Some interesting new cosmological solutions for the very early universe are found, including the possibility of a bounce, inflation and expansion with a loitering phase, all of which are induced by early variations in alpha.

John D. Barrow; Joao Magueijo



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.


Beta/alpha continuous air monitor  


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)



Beta/alpha continuous air monitor  


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.



On strongly [alpha]-preinvex functions  

NASA Astrophysics Data System (ADS)

In this paper, by means of a series of counterexamples, we study in a systematic way the relationships among (pseudo, quasi) [alpha]-preinvexity, (strict, strong, pseudo, quasi) [alpha]-invexity and (strict, strong, pseudo, quasi) [alpha][eta]-monotonicity. Results obtained in this paper can be viewed as a refinement and improvement of the results of Noor and Noor [M.A. Noor, K.I. Noor, Some characterizations of strongly preinvex functions, J. Math. Anal. Appl. 316 (2006) 697-706].

Fan, Liya; Guo, Yunlian



Satellite Ballistic Coefficients and the Lower Thermosphere  

NASA Astrophysics Data System (ADS)

The observed variations in the 'estimated' ballistic coefficients (B') for low-perigee satellites in the lower thermosphere (about 200 km) during the year 2001, have been used to study their implications for neutral atmospheric densities with respect to changes in the solar activity and geomagnetic activity. The changes in B' reflect the unmodeled corrections in the atmospheric density models. It is shown that statistically, on the average, based on the 'true' ballistic coefficients (Bt), the atmospheric density models predict the 'true' density within 10 percent as a function of solar activity for quiet and mild geomagnetic periods. The observed variations in the ballistic coefficients with days exhibit a semiannual variation (SAV). The 'scaling' factor required to correctly predict the SAV in the 'true' densities from the model densities, ranges from a maximum of about 1.13 in the spring (equinox) to a minimum of about 0.93 in the summer (solstice), implying a semiannual amplitude(SAA) of (max/min) 1.2. The calculations based on the CIRA-86 models show that changes in B' during some major magnetic storms cannot be explained, as they are probably contaminated by 'high density neutral cells' observed by the S85-1 satellite at 200 km and predicted by the NCAR-TIGCM models by Crowley, et al (1995). Changes in B' due to these cells all the more require temperature/density corrections of the steady-state High Accuracy Satellite Drag Model (HASDM). It is suggested that the NCAR-TIGCM model should be used to see if it performs better in bringing the B' values closer to Bt than the steady-state models.

Bhatnagar, V. P.; Germany, G. A.; Tan, A.; Wu, S. T.



Peltier coefficient measurement in a thermoelectric module  

NASA Astrophysics Data System (ADS)

A new method for measuring the Peltier coefficient in a thermocouple X/Y based on the energy balance at the junction has been proposed recently. This technique needs only the hot and cold temperatures of a thermoelectric module when an electric current flows through it as the operational variables. The temperature evolutions of the two module sides provide an evident and accurate idea of the Peltier effect. From these temperatures, the heat transfer between the module and the ambient is also evaluated. The thermoelectric phenomena are described in the framework of an observable theory. Based on this procedure, an experiment is presented for a university teaching laboratory at the undergraduate level.

Garrido, Javier; Casanovas, Alejandro; María Chimeno, José



Using CFD software to calculate hydrodynamic coefficients  

NASA Astrophysics Data System (ADS)

Applications of computational fluid dynamic (CFD) to the maritime industry continue to grow with the increasing development of computers. Numerical approaches have evolved to a level of accuracy which allows them to be applied for hydrodynamic computations in industry areas. Hydrodynamic tests, especially planar-motion-mechanism (PMM) tests are simulated by CFD software -FLUENT, and all of the corresponding hydrodynamic coefficients are obtained, which satisfy the need of establishing the simulation system to evaluate maneuverability of vehicles during the autonomous underwater vehicle scheme design stage. The established simulation system performed well in tests.

Zhang, He; Xu, Yu-Ru; Cai, Hao-Peng



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.



Surface area coefficients for airship envelopes  

NASA Technical Reports Server (NTRS)

In naval architecture, it is customary to determine the wetted surface of a ship by means of some formula which involves the principal dimensions of the design and suitable constants. These formulas of naval architecture may be extended and applied to the calculation of the surface area of airship envelopes by the use of new values of the constants determined for this purpose. Surface area coefficients were calculated from the actual dimensions, surfaces, and volumes of 52 streamline bodies, which form a series covering the entire range of shapes used in the present aeronautical practice.

Diehl, W S



Transport coefficients of a massive pion gas  

E-print Network

We review or main results concerning the transport coefficients of a light meson gas, in particular we focus on the case of a massive pion gas. Leading order results according to the chiral power-counting are presented for the DC electrical conductivity, thermal conductivity, shear viscosity, and bulk viscosity. We also comment on the possible correlation between the bulk viscosity and the trace anomaly in QCD, as well as the relation between unitarity and a minimum of the quotient $\\eta/s$ near the phase transition.

D. Fernandez-Fraile; A. Gomez Nicola



A transport coefficient: the electrical conductivity  

E-print Network

I describe the lattice determination of the electrical conductivity of the quark gluon plasma. Since this is the first extraction of a transport coefficient with a degree of control over errors, I next use this to make estimates of other transport related quantities using simple kinetic theory formulae. The resulting estimates are applied to fluctuations, ultra-soft photon spectra and the viscosity. Dimming of ultra-soft photons is exponential in the mean free path, and hence is a very sensitive probe of transport.

Sourendu Gupta



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.



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



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.



Renal handling of Zn-alpha2-glycoprotein as compared with that of albumin and the retinol-binding protein.  

PubMed Central

An unusual electrophoretic pattern of the urine from a patient with malignant lymphoma was observed. One of the major proteins, identified Zn-alpha2-glycoprotein (Zn-alpha2), was isolated from the urine and partly characterized. The Stokes radius was found to be 3.24 nm and the molecular weight, determined by sodium dodecyl sulfate polyacrylamide electrophoresis, 42,000. The plasma level in healthy individuals was 39 +/- 7 (SD) mg/liter. In 12 of 25 healthy individuals, Zn-alpha2 was measurable in the urine and was found to be 1.0 +/- 1.1 mg/liter. In 23 patients with chronic glomerulonephritis (CGN), in 9 with proximal tubular dysfunction (PTD), in 23 with various renal diseases (VRD), and in 10 with malignant lymphoma, the plasma level and the urinary excretion were compared with those of albumin (mol wt 67,000) and of the retinol-binding protein (RBP, mol wt 21,000). A close correlation was found between the urine-to-plasma (U/P) ratios of Zn-alpha2 and albumin in the patients with CGN, whereas in the PTD patients the U/P ratios of Zn-alpha2 and RBP were correlated. No significant renal arteriovenous difference in Zn-alpha2 could be demonstrated. The Zn-alpha2 excretion was increased also in two patients with malignant lymphoma and proteinuria of a tubular pattern. The plasma Zn-alpha2 varied inversely with the glomerular filtration rate in the patients with renal disease, but was normal in those with malignant lymphoma. The results are consistent with the assumption of a sieving coefficient of Zn-alpha2, substantially exceeding that of albumin, but notably lower than that of smaller low-molecular-weight proteins. An increased excretion of Zn-alpha2 may be due to increased glomerular permeability as well as to defective proximal tubular reabsorption. Images PMID:985827

Ekman, R; Johansson, B G; Ravnskov, U



/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.



The first transformation of aliphatic alpha,beta-epoxyamides into alpha-hydroxyamides.  


A general synthesis of aliphatic alpha-hydroxyamides with total regioselectivity by a reductive cleaveage of the C(beta)-O bond of aliphatic alpha,beta-epoxyamides, promoted by samarium diiodide and MeOH, is described. The treatment of enantiopure aliphatic alpha,beta-epoxyamides afforded enantiomerically enriched aliphatic alpha-hydroxyamides. A radical mechanism has been proposed to explain this reaction. [reaction: see text] PMID:14653673

Concellón, José M; Bardales, Eva



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. PMID:24385886

Schofield, Norman



Rotordynamic coefficients for stepped annular gas seals  

NASA Astrophysics Data System (ADS)

Governing equations for the flow through high-pressure annular step seals typical of floating ring seals employed in aircraft gas turbines are identified. These equations are based on a fully developed bulk-flow model using Moody's friction factor equation, and two empirical loss coefficient expressions. All terms in the governing equations (including circumferential velocity, convective acceleration, and shear dissipation) are retained, and a perturbation/numerical integration solution technique is developed to solve these equations. The analysis procedure is then applied to three different stepped seal configurations. In each case, the stepped seals leaked more than corresponding straight seals. The stepped seals also have smaller whirl stability ratios, thus reducing the destabilizing effect on forward whirling rotors. However, the effect of a step on the direct stiffness coefficient was mixed. For two of the configurations, the introduction of a step always increased direct stiffness. But in the third case, a small step resulted in decreasing direct stiffness from a positive value to a negative value. As step height increased further, the stiffness again became positive.

Nelson, Clayton C.; Dunn, Mark S.; Scharrer, Joseph K.


Coefficient adaptive triangulation for strongly anisotropic problems  

SciTech Connect

Second order elliptic partial differential equations arise in many important applications, including flow through porous media, heat conduction, the distribution of electrical or magnetic potential. The prototype is the Laplace problem, which in discrete form produces a coefficient matrix that is relatively easy to solve in a regular domain. However, the presence of anisotropy produces a matrix whose condition number is increased, making the resulting linear system more difficult to solve. In this work, we take the anisotropy into account in the discretization by mapping each anisotropic region into a ``stretched`` coordinate space in which the anisotropy is removed. The region is then uniformly triangulated, and the resulting triangulation mapped back to the original space. The effect is to generate long slender triangles that are oriented in the direction of ``preferred flow.`` Slender triangles are generally regarded as numerically undesirable since they tend to cause poor conditioning; however, our triangulation has the effect of producing effective isotropy, thus improving the condition number of the resulting coefficient matrix.

D`Azevedo, E.F.; Romine, C.H.; Donato, J.M.



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



Development of the feedwater venturi fouling coefficient  

SciTech Connect

Duke Power Company's Oconee Nuclear Generating Station (NGS), a three-unit plant with Babcock and Wilcox nuclear steam supply systems, experienced symptoms of feedwater venturi fouling. These symptoms included decreased reactor power output while indicated thermal power remained at 100% of licensed thermal power, resulting in decreased electrical output during the operating cycle. To recover this lost generating capacity, a methodology to quantify and account for the effects of fouling using plant instrumentation was developed and implemented. By introducing a feedwater venturi fouling coefficient into the feedwater flow calculation, reactor power can be maintained at full licensed power. The result of this effort was the recovery of > 40 MW of lost generating capabilities at the Oconee NGS. Cost savings from replacement power alone is in excess of $5 million/yr. Additional savings are realized because of increased fuel use. By showing the plant's calorimetric uncertainty can remain less than [plus minus] 2% of full power, no safety or accident analysis is invalidated. Furthermore, because of its low implementation cost, determining the fouling coefficient from plant instrumentation is an attractive alternative to standard methods currently used.

Gillespie, T.P. Jr.



On Learning Cluster Coefficient of Private Networks  

PubMed Central

Enabling accurate analysis of social network data while preserving differential privacy has been challenging since graph features such as clustering coefficient or modularity often have high sensitivity, which is different from traditional aggregate functions (e.g., count and sum) on tabular data. In this paper, we treat a graph statistics as a function f and develop a divide and conquer approach to enforce differential privacy. The basic procedure of this approach is to first decompose the target computation f into several less complex unit computations f1, …, fm connected by basic mathematical operations (e.g., addition, subtraction, multiplication, division), then perturb the output of each fi with Laplace noise derived from its own sensitivity value and the distributed privacy threshold ?i, and finally combine those perturbed fi as the perturbed output of computation f. We examine how various operations affect the accuracy of complex computations. When unit computations have large global sensitivity values, we enforce the differential privacy by calibrating noise based on the smooth sensitivity, rather than the global sensitivity. By doing this, we achieve the strict differential privacy guarantee with smaller magnitude noise. We illustrate our approach by using clustering coefficient, which is a popular statistics used in social network analysis. Empirical evaluations on five real social networks and various synthetic graphs generated from three random graph models show the developed divide and conquer approach outperforms the direct approach. PMID:24429843

Wang, Yue; Wu, Xintao; Zhu, Jun; Xiang, Yang



Rotordynamic coefficients for stepped labyrinth gas seals  

NASA Technical Reports Server (NTRS)

The basic equations are derived for compressible flow in a stepped labyrinth gas seal. The flow is assumed to be completely turbulent in the circumferential direction where the friction factor is determined by the Blasius relation. Linearized zeroth and first-order perturbation equations are developed for small motion about a centered position by an expansion in the eccentricity ratio. The zeroth-order pressure distribution is found by satisfying the leakage equation while the circumferential velocity distribution is determined by satisfying the momentum equations. The first order equations are solved by a separation of variables solution. Integration of the resultant pressure distribution along and around the seal defines the reaction force developed by the seal and the corresponding dynamic coefficients. The results of this analysis are presented in the form of a parametric study, since there are no known experimental data for the rotordynamic coefficients of stepped labyrinth gas seals. The parametric study investigates the relative rotordynamic stability of convergent, straight and divergent stepped labyrinth gas seals. The results show that, generally, the divergent seal is more stable, rotordynamically, than the straight or convergent seals. The results also show that the teeth-on-stator seals are not always more stable, rotordynamically, then the teeth-on-rotor seals as was shown by experiment by Childs and Scharrer (1986b) for a 15 tooth seal.

Scharrer, Joseph K.



Radon diffusion coefficients in soils of varying moisture content  

NASA Astrophysics Data System (ADS)

Radon is a naturally occurring radioactive gas that is generated in the Earth's crust and is free to migrate through soil and be released to the atmosphere. Due to its unique properties, soil gas radon has been established as a powerful tracer used for a variety of purposes, such as exploring uranium ores, locating geothermal resources and hydrocarbon deposits, mapping geological faults, predicting seismic activity or volcanic eruptions and testing atmospheric transport models. Much attention has also been given to the radiological health hazard posed by increased radon concentrations in the living and working environment. In order to exploit radon profiles for geophysical purposes and also to predict its entry indoors, it is necessary to study its transport through soils. Among other factors, the importance of soil moisture in such studies has been largely highlighted and it is widely accepted that any measurement of radon transport parameters should be accompanied by a measurement of the soil moisture content. In principle, validation of transport models in the field is encountered by a large number of uncontrollable and varying parameters; laboratory methods are therefore preferred, allowing for experiments to be conducted under well-specified and uniform conditions. In this work, a laboratory technique has been applied for studying the effect of soil moisture content on radon diffusion. A vertical diffusion chamber was employed, in which radon was produced from a 226Ra source, was allowed to diffuse through a soil column and was finally monitored using a silicon surface barrier detector. By solving the steady-state radon diffusion equation, diffusion coefficients (D) were determined for soil samples of varying moisture content (m), from null (m=0) to saturation (m=1). For dry soil, a D value of 4.1×10-7 m2s-1 was determined, which increased moderately by a factor of ~3 for soil with low moisture content, i.e. up to m ~0.2. At higher water fractions, a decrease in D was initiated and became particularly pronounced approaching complete saturation; at m =0.9, D was as low as 2×10-9 m2s-1. A series of field experiments has also been conducted using alpha-track CR-39 detectors to follow the moisture-dependence of radon diffusion through soil under natural conditions. Diffusion coefficients were determined as a function of surface soil moisture assuming a one-dimensional diffusive radon transport model. Comparison between results obtained by the two methods showed that laboratory studies may provide a good indication of radon diffusion coefficients to be expected in the field. However, values determined in the field were systematically lower than those assessed in the laboratory. This finding could be attributed to soil-dependent parameters, such as differences in pore space geometry between the soil used in laboratory experiments and the undisturbed soil. In the latter case, the higher degree of compaction imposes a more tortuous pathway to soil gas, while at the same time the diffusive gas flux is hindered by local-scale zones of higher bulk density or water content.

Papachristodoulou, C.; Ioannides, K.; Pavlides, S.



Stereoselective desymmetrisation of prochiral alpha,alpha-dicyanoalkenes via domino Michael-Michael addition reactions.  


The desymmetrisation of prochiral alpha,alpha-dicyanoalkenes via tandem Michael-Michael addition reactions with alpha,beta-unsaturated ketones catalysed by 9-amino-9-deoxyepicinchona alkaloids was investigated, from which bicyclic products bearing four stereogenic centers were afforded in a single operation with high stereoselectivities (>99% de, up to >99.5% ee). PMID:18633522

Kang, Tai-Ran; Xie, Jian-Wu; Du, Wei; Feng, Xin; Chen, Ying-Chun



Alpha-conotoxin PIA is selective for alpha6 subunit-containing nicotinic acetylcholine receptors.  


Until now, there have been no antagonists to discriminate between heteromeric nicotinic acetylcholine receptors (nAChRs) containing the very closely related alpha6 and alpha3 subunits. nAChRs containing alpha3, alpha4, or alpha6 subunits in combination with beta2, occasionally beta4, and sometimes beta3 or alpha5 subunits, are thought to play important roles in cognitive function, pain perception, and the reinforcing properties of nicotine. We cloned a novel gene from the predatory marine snail Conus purpurascens. The predicted peptide, alpha-conotoxin PIA, potently blocks the chimeric alpha6/alpha3beta2beta3 subunit combination as expressed in oocytes but neither the muscle nor the major neuronal nAChR alpha4beta2. Additionally, this toxin is the first described ligand to discriminate between nAChRs containing alpha6 and alpha3 subunits. Exploiting the unusual intron conservation of conotoxin genes may represent a more general approach for defining conotoxin ligand scaffolds to discriminate among closely related receptor populations. PMID:13679412

Dowell, Cheryl; Olivera, Baldomero M; Garrett, James E; Staheli, Sarah T; Watkins, Maren; Kuryatov, Alexander; Yoshikami, Doju; Lindstrom, Jon M; McIntosh, J Michael



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

SciTech Connect

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, D/P, in the Generic Environmental Impact Statement on Uranium Milling prepared by the US Nuclear Regulatory Commission. Two soils were tested: a well-graded sand and an inorganic clay of low plasticity. For the flux evaluations, radon was collected by adsorption on charcoal following passive diffusion from the soil surface and also from air recirculating through an aluminum tent over the soil surface. An analysis of variance in the flux evaluations showed no significant difference between these two collection methods. Radon diffusion coefficients evaluated from field data were statistically indistinguishable, at the 95% confidence level, from those measured in the laboratory; however, the low precision of the field data prevented a sensitive validation of the laboratory measurements. From the field data, the coefficients were calculated to be 0.03 +- 0.03 cm/sup 2//s for the sand cover and 0.0036 +- 0.0004 cm/sup 2//s for the clay cover. The low precision in the coefficients evaluated from field data was attributed to high variation in radon flux with time and surface location at the field site.

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



Evidence for an alpha cluster condensed state in 16O(alpha,alpha') at 400 MeV  

E-print Network

Inelastic $\\alpha$ scattering on 16O is studied at 400 MeV by using an ice target. Near the 4-alpha breakup threshold of 14.4 MeV, a broad peak is observed at an excitation energy of 13.6+/-0.2 MeV with a width of 0.6+/-0.2 MeV. The spin-parity is estimated to be 0+ from the momentum-transfer dependence. The observed width is significantly larger than those of the neighboring 0+ states indicating a state with a well-developed alpha cluster structure. The magnitude of the cross section is sensitive to the density distribution of the constituent alpha clusters. The observed cross section is consistent with the theoretical prediction for the alpha cluster condensed state characterized by its dilute density distribution with a large root-mean-square radius of about 4.3 fm.

T. Wakasa; E. Ihara; K. Fujita; Y. Funaki; K. Hatanaka; H. Horiuchi; M. Itoh; J. Kamiya; G. Ropke; H. Sakaguchi; N. Sakamoto; Y. Sakemi; P. Schuck; Y. Shimizu; M. Takashina; S. Terashima; A. Tohsaki; M. Uchida; H. P. Yoshida; M. Yosoi



Calculation of combined diffusion coefficients in SF6-Cu mixtures  

NASA Astrophysics Data System (ADS)

Diffusion coefficients play an important role in the description of the transport of metal vapours in gas mixtures. This paper is devoted to the calculation of four combined diffusion coefficients, namely, the combined ordinary diffusion coefficient, combined electric field diffusion coefficient, combined temperature diffusion coefficient, and combined pressure diffusion coefficient in SF6-Cu mixtures at temperatures up to 30 000 K. These four coefficients describe diffusion due to composition gradients, applied electric fields, temperature gradients, and pressure gradients, respectively. The influence of copper fluoride and sulfide species on the diffusion coefficients is shown to be negligible. The effect of copper proportion and gas pressures on these diffusion coefficients is investigated. It is shown that increasing the proportion of copper generally increases the magnitude of the four diffusion coefficients, except for copper mole fractions of 90% or more. It is further found that increasing the pressure reduces the magnitude of the coefficients, except for the combined temperature diffusion coefficient, and shifts the maximum of all four coefficients towards higher temperatures. The results presented in this paper can be applied to the simulation of high-voltage circuit breaker arcs.

Zhong, Linlin; Wang, Xiaohua; Rong, Mingzhe; Wu, Yi; Murphy, Anthony B.



Local Varying-Alpha Theories  

E-print Network

In a recent paper we demonstrated how the simplest model for varying alpha may be interpreted as the effect of a dielectric material, generalized to be consistent with Lorentz invariance. Unlike normal dielectrics, such a medium cannot change the speed of light, and its dynamics obey a Klein-Gordon equation. This work immediately suggests an extension of the standard theory, even if we require compliance with Lorentz invariance. Instead of a wave equation, the dynamics may satisfy a local algebraic relation involving the permittivity and the properties of the electromagnetic field, in analogy with more conventional dielectric (but still preserving Lorentz invariance). We develop the formalism for such theories and investigate some phenomenological implications. The problem of the divergence of the classical self-energy can be solved, or at least softened, in this framework. Some interesting new cosmological solutions for the very early universe are found, including the possibility of a bounce, inflation and e...

Barrow, John D



Permeation study of five formulations of alpha-tocopherol acetate through human cadaver skin.  


Alpha-tocopherol (AT) is the vitamin E homologue with the highest in vivo biological activity. AT protects against the carcinogenic and mutagenic activity of ionizing radiation and chemical agents, and possibly against UV-induced cutaneous damage. For stability consideration, alpha-tocopherol is usually used as its prodrug ester, alpha-tocopherol acetate (ATA), which once absorbed into the skin is hydrolyzed to alpha-tocopherol, the active form. The objective of this research was to characterize in vitro the permeation properties of ATA from various solutions and gel formulations. Permeation studies were conducted using modified Franz diffusion cells and human cadaver skin as the membrane. Specifically, 5% (w/w) alpha-tocopherol acetate was formulated in the following vehicles: ethanol, isopropyl myristate, light mineral oil, 1% Klucel gel in ethanol, and 3% Klucel gel in ethanol (w/w). The receiver temperature was 37 degrees C. Samples from the receiver were collected at 2, 4, 6, 8, 12, 24, 30, 36, and 48 hours and analyzed by HPLC for concentrations of alpha-tocopherol acetate and alpha-tocopherol. The permeabilities of ATA through human cadaver skin were 1.0x10(-4), 1.1x10(-2), 1.4x10(-4), 2.1x10(-4), and 4.7x10(-4) cm/h for the ethanol solution, isopropyl myristate solution, light mineral oil solution, 1% Klucel gel, and 3% Klucel gel, respectively. The results show that the formulation had relatively minor effects on the permeability coefficients of ATA through cadaver skin in all cases except for the isopropyl myristate solution. PMID:15868062

Mahamongkol, Hansa; Bellantone, Robert A; Stagni, Grazia; Plakogiannis, Fotios M



Alpha-1 Antitrypsin Deficiency: It's All in the Family  


... It’s All in the Family Whether you have Alpha-1 Antitrypsin Deficiency (Alpha-1) — or are an Alpha-1 “carrier” — we strongly suggest that your relatives ... share with them what you have learned about Alpha-1. How is Alpha-1 inherited? Your genes ...


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



Recovering DC coefficients in block-based DCT.  


It is a common approach for JPEG and MPEG encryption systems to provide higher protection for dc coefficients and less protection for ac coefficients. Some authors have employed a cryptographic encryption algorithm for the dc coefficients and left the ac coefficients to techniques based on random permutation lists which are known to be weak against known-plaintext and chosen-ciphertext attacks. In this paper we show that in block-based DCT, it is possible to recover dc coefficients from ac coefficients with reasonable image quality and show the insecurity of image encryption methods which rely on the encryption of dc values using a cryptoalgorithm. The method proposed in this paper combines dc recovery from ac coefficients and the fact that ac coefficients can be recovered using a chosen ciphertext attack. We demonstrate that a method proposed by Tang to encrypt and decrypt MPEG video can be completely broken. PMID:17076416

Uehara, Takeyuki; Safavi-Naini, Reihaneh; Ogunbona, Philip




Technology Transfer Automated Retrieval System (TEKTRAN)

Crop coefficients are a widely used and universally accepted method for estimating the crop evapotranspiration (ETc) component in irrigation scheduling programs. However, uncertainties of generalized basal crop coefficient (Kcb) curves can contribute to ETc estimates that are substantially different...


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:



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.



Alpha-thalassemia in two Mediterranean populations.  


We used restriction endonuclease analysis to determine the incidence of alpha-thalassemia in two Mediterranean islands. In a random population sample, the gene frequency of deletion-type alpha-thalassemia-2 (-alpha) was 0.18 in Sardinians and 0.07 in Greek Cypriots. All cases were the rightward crossover type. From these frequencies and the known incidence of hemoglobin-H disease in these populations, we calculated the frequency of the alpha-thalassemia-1 genotype (--) and determined that it was low. We also found that beta-thalassemia homozygotes in sardinia have a higher incidence of alpha-thalassemia than normals and beta thalassemia heterozygotes because a significantly greater number of these homozygotes are also homozygous for the alpha-thalassemia-2 lesion. These findings support the theory that coinheritance of alpha-thalassemia mitigates the severity of beta-thalassemia and suggest that the protection is most pronounced when two alpha-globin genes are deleted. PMID:7093530

Pirastu, M; Lee, K Y; Dozy, A M; Kan, Y W; Stamatoyannopoulos, G; Hadjiminas, M G; Zachariades, Z; Angius, A; Furbetta, M; Rosatelli, C; Cao, A



27 CFR 21.95 - Alpha terpineol.  

Code of Federal Regulations, 2011 CFR

...and Firearms 1 2011-04-01 2011-04-01 false Alpha terpineol. 21.95 Section 21.95 Alcohol, Tobacco...ALCOHOL AND RUM Specifications for Denaturants § 21.95 Alpha terpineol. (a) Boiling point at 752mm...



Teaching Calculus with Wolfram|Alpha  

ERIC Educational Resources Information Center

This article describes the benefits and drawbacks of using Wolfram|Alpha as the platform for teaching calculus concepts in the lab setting. It is a result of our experiences designing and creating an entirely new set of labs using Wolfram|Alpha. We present the reasoning behind our transition from using a standard computer algebra system (CAS) to…

Dimiceli, Vincent E.; Lang, Andrew S. I. D.; Locke, LeighAnne



27 CFR 21.95 - Alpha terpineol.  

Code of Federal Regulations, 2010 CFR

...and Firearms 1 2010-04-01 2010-04-01 false Alpha terpineol. 21.95 Section 21.95 Alcohol, Tobacco...ALCOHOL AND RUM Specifications for Denaturants § 21.95 Alpha terpineol. (a) Boiling point at 752mm...



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



Fatty acylation of alpha z. Effects of palmitoylation and myristoylation on alpha z signaling.  


As the first step in an investigation of roles played by fatty acylation of G protein alpha chains in membrane targeting and signal transmission, we inserted monoclonal antibody epitopes, hemagglutinin (HA) or Glu-Glu (EE), at two internal sites in three alpha subunits. At site I, only HA-tagged alpha q and alpha z functioned normally. alpha s, alpha q, and alpha z subunits tagged at site II with the EE epitope showed normal expression, membrane localization, and signaling activity. Using epitope-tagged alpha z, we investigated effects of mutations in sites for fatty acylation. Mutational substitution of Ala for Gly2 (G2A) prevented incorporation of myristate and decreased but did not abolish incorporation of palmitate. Substitution of Ala for Cys3 (C3A) prevented incorporation of palmitate but had no effect on incorporation of myristate. Substitution of Ala for both Gly2 and Cys3 (G2AC3A) prevented incorporation of both myristate and palmitate. All three mutations substantially disrupted association of alpha z with the particulate fraction. Gz-mediated inhibition of adenylyl cyclase, triggered by activation of the D2-dopamine receptor, was, respectively, abolished (G2AC3A), impaired (G2A), and enhanced (C3A). Constitutive inhibition of adenylyl cyclase by alpha z was unchanged (G2AC3A), strongly diminished (G2A), or strongly enhanced (C3A). A nonacylated, mutationally activated alpha z mutant inhibited adenylyl cyclase, although less potently than normally acylated, mutationally activated alpha z. From these findings we conclude: (a) fatty acylations of alpha z increase its association with membranes; (b) myristoylation is not required for palmitoylation of alpha z or for its productive interactions with adenylyl cyclase; (c) palmitoylation is not required for, but may instead inhibit, signaling by alpha z. PMID:7536745

Wilson, P T; Bourne, H R



Remarks on "Calculation of the quarkonium spectrum and $m_{b}$, $m_{c}$ to order $\\alpha_{s}^{4}$"  

E-print Network

In a recent paper, we included two-loop, relativistic one-loop, and second-order relativistic tree level corrections, plus leading nonperturbative contributions, to obtain a calculation of the lower states in the heavy quarkonium spectrum correct up to, and including, O( alpha /sub s//sup 4/) and leading Lambda /sup 4//m/sup 4/ terms. The results were obtained with, in particular, the value of the two- loop static coefficient due to Peter; this has been recently challenged by Schroder. In our previous paper we used Peter's result; in the present one we now give results with Schroder's, as this is likely to be the correct one. The variation is slight as the value of b/sub 1/ is only one among the various O( alpha /sub s//sup 4/) contributions. With Schroder's expression we now have m/sub b/=5001 /sub -66//sup +104/ MeV, m/sub b/(m/sub b//sup 2/)=4454/sub -29//sup +45/ MeV, m/sub c/=1866/sub -133//sup +215/ MeV, m/sub c/(m/sub c //sup 2/)=1542/sub -104//sup +163/ MeV. Moreover, Gamma ( Upsilon to e/sup +/e/sup ...

Pineda-Ruiz, A



Calculation of sensitivity coefficients for a neutron well logging tool  

E-print Network

to the Formation Porosity . IV. 3 Sensitivity Coefficients Due to the Medium Porosity . . IV. 4 Sensitivity Coefficients Due to the Medium Thickness . V CONCLUSIONS 26 26 27 31 33 REFERENCES APPENDIX 34 A s4'AM ? BE NEUTRON SOURCE SPECTRUM . . 35 B... Coefficients Due to the Medium Porosity 30 9 Sensitivity Coefficients Due to the Medium Thickness 10 Am ? Be Neutron Source Spectrum 32 37 CHAPTER I INTRODUCTION I. l Background of Neutron Well Logging In oil snd natural gas well logging...

Chen, Chien-Hsiang



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


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



Improved peak shape fitting in alpha spectra.  


Peak overlap is a recurrent issue in alpha-particle spectrometry, not only in routine analyses but also in the high-resolution spectra from which reference values for alpha emission probabilities are derived. In this work, improved peak shape formulae are presented for the deconvolution of alpha-particle spectra. They have been implemented as fit functions in a spreadsheet application and optimum fit parameters were searched with built-in optimisation routines. Deconvolution results are shown for a few challenging spectra with high statistical precision. The algorithm outperforms the best available routines for high-resolution spectrometry, which may facilitate a more reliable determination of alpha emission probabilities in the future. It is also applicable to alpha spectra with inferior energy resolution. PMID:25497323

Pommé, S; Caro Marroyo, B



Transport coefficients in weakly compressible turbulence  

NASA Astrophysics Data System (ADS)

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, Yoshizawa's two-scale approximation generates terms in the mean flow equations which contain gradients of incompressible turbulence quantities. A preliminary description of these terms is given.

Rubinstein, Robert; Erlebacher, Gordon



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.



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



QRS detection based on wavelet coefficients.  


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



Determination of alpha_s from the QCD static energy: an update  

E-print Network

We present an update of our determination of the strong coupling alpha_s from the quantum chromodynamics static energy. This updated analysis includes new lattice data, at smaller lattice spacings and reaching shorter distances, the use of better suited perturbative expressions to compare with data in a wider distance range, and a comprehensive and detailed estimate of the error sources that contribute to the uncertainty of the final result. Our updated value for alpha_s at the Z-mass scale, M_Z, is alpha_s(M_Z)=0.1166^{+0.0012}_{-0.0008}, which supersedes our previous result.

Alexei Bazavov; Nora Brambilla; Xavier Garcia i Tormo; Peter Petreczky; Joan Soto; Antonio Vairo



A new numerical method for conversion of sonic second virial coefficients to density second virial coefficients  

E-print Network

. The objectives of this research are (1) to prove that our method is more accurate than existing methods for extracting second density virial coefficients from sonic velocity data, (2) to illustrate that the new numerical method is much simpler in convening sonic...

Mossaad, Ehab



Sedimentation Coefficient, Frictional Coefficient, and Molecular Weight: A Preparative Ultracentrifuge Experiment for the Advanced Undergraduate Laboratory.  

ERIC Educational Resources Information Center

Describes an experiment using a high-speed preparative centrifuge and calculator to demonstrate effects of the frictional coefficient of a macromolecule on its rate of transport in a force field and to estimate molecular weight of the macromolecule using an empirical relationship. Background information, procedures, and discussion of results are…

Halsall, H. B.; Wermeling, J. R.



Turbulent Drag Coefficients Of Sharp-Edged Objects  

Microsoft Academic Search

Determination of drag coefficients from the conventional plots of drag coefficient, CD, versus Reynolds number, Re, is inadequate in the case of turbulent flow. Dimensional analysis has shown that the drag coefficient is a function of turbulence intensity, U , dimensionless turbulence scale, ?\\/D, and Reynolds number, Re. These parameters were combined in one term called the turbulence characteristics, ,

Walter H. Graf; Farid F. Mansour




E-print Network

FETCH LIMITED DRAG COEFFICIENTS DEAN VICKERS and L. MAHRT College of Oceanic and Atmospheric the Risø Air Sea Experiment (RASEX) are analyzed to investigate the behaviour of the drag coefficient in the coastal zone. For a given wind speed, the drag coefficient is larger during conditions of short fetch (2

Vickers, Dean


Fractal Transition Model in Predicting Static Friction Coefficient  

Microsoft Academic Search

There is a fractal characteristic in most engineering surfaces. Effects of the surface fractal parameters D, G and the material parameter ? on the static friction coefficient are discussed. The predicted static friction coefficient increases with the increase of normal load. This coincides with the fact that static friction coefficient is very low under very small normal load condition. Second,

Sui Changfu; Sheng Xuanyu



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.




E-print Network

dependency of the ultrasonic attenuation coefficient ranges from f * e to fl.3 6 and its magnitude at 1 MHzFREQUENCY DEPENDENT ULTRASONIC ATTENUATION COEFFICIENT ASSESSMENT IN FRESH TISSUE Laurie A . Segal 61801 Abstract Ultrasonic attenuation coefficient measurements were made at 1.4, 4.2, 7.0 and 9.8 MHz

Illinois at Urbana-Champaign, University of


Young modulus dependence of nanoscopic friction coefficient in hard coatings  

E-print Network

Young modulus dependence of nanoscopic friction coefficient in hard coatings Elisa Riedoa in the friction coefficient can be traced back to variations of the Young modulus. More generally, we show for all samples investigated and in wearless regime, that the nanoscopic friction coefficient is directly linked

Brune, Harald


Friction coefficient of soft contact lenses: measurements and modeling  

E-print Network

Friction coefficient of soft contact lenses: measurements and modeling A.C. Rennie, P.L. Dickrell and compared to the experimental data. The experimental friction coefficients vary from l = 0.025 to 0 contact pressure conditions. Nairn and Jiang [3] reported the friction coefficients of polyhydroxy ethyl

Sawyer, Wallace


Friction Coefficient Analysis of Multicomponent Solute Transport Through Polymer Membranes  

E-print Network

Friction Coefficient Analysis of Multicomponent Solute Transport Through Polymer Membranes their parameters are derived. The impor- tance of the friction coefficients in determining the response of the membrane suggests that a deeper look at the causes of the friction is necessary. New friction coefficient

Peppas, Nicholas A.


Measurement of friction coefficients with the atomic force microscope  

E-print Network

Measurement of friction coefficients with the atomic force microscope Phil Attard1, Johanna axial method for measuring the friction coefficient with the atomic force microscope is given curves. The algorithm can be applied retrospectively to extract the friction coefficient from preexisting

Attard, Phil


ORIGINAL PAPER Friction Coefficient Measurement of Hydrogel Materials  

E-print Network

ORIGINAL PAPER Friction Coefficient Measurement of Hydrogel Materials on Living Epithelial Cells and variable environments. The friction coefficient of these contacts involving living human cells is of key a custom micro-tribometer. The friction coefficients were of the order of l = 0.03 for contacts that did

Sawyer, Wallace


METHODS PAPER Addressing Practical Challenges of Low Friction Coefficient  

E-print Network

METHODS PAPER Addressing Practical Challenges of Low Friction Coefficient Measurements D. L. Burris 2009 Ã? Springer Science+Business Media, LLC 2009 Abstract A friction coefficient is defined calculation, there are practical challenges that make low values of friction coefficient difficult

Sawyer, Wallace


How To Prepare Materials With a Desired Refraction Coefficient  

E-print Network

How To Prepare Materials With a Desired Refraction Coefficient A G Ramm Department of Mathematics is described for preparing materials with a desired refraction coefficient. The method consists of embedding into a material with known refraction coefficient many small particles of size a. The number of particles per unit


Alpha1 and Alpha2 Integrins Mediate Invasive Activity of Mouse Mammary Carcinoma Cells through Regulation of Stromelysin-1 Expression  

SciTech Connect

Tumor cell invasion relies on cell migration and extracellular matrix proteolysis. We investigated the contribution of different integrins to the invasive activity of mouse mammary carcinoma cells. Antibodies against integrin subunits {alpha}6 and {beta}1, but not against {alpha}1 and {alpha}2, inhibited cell locomotion on a reconstituted basement membrane in two-dimensional cell migration assays, whereas antibodies against {beta}1, but not against a6 or {alpha}2, interfered with cell adhesion to basement membrane constituents. Blocking antibodies against {alpha}1 integrins impaired only cell adhesion to type IV collagen. Antibodies against {alpha}1, {alpha}2, {alpha}6, and {beta}1, but not {alpha}5, integrin subunits reduced invasion of a reconstituted basement membrane. Integrins {alpha}1 and {alpha}2, which contributed only marginally to motility and adhesion, regulated proteinase production. Antibodies against {alpha}1 and {alpha}2, but not {alpha}6 and {beta}1, integrin subunits inhibited both transcription and protein expression of the matrix metalloproteinase stromelysin-1. Inhibition of tumor cell invasion by antibodies against {alpha}1 and {alpha}2 was reversed by addition of recombinant stromelysin-1. In contrast, stromelysin-1 could not rescue invasion inhibited by anti-{alpha}6 antibodies. Our data indicate that {alpha}1 and {alpha}2 integrins confer invasive behavior by regulating stromelysin-1 expression, whereas {alpha}6 integrins regulate cell motility. These results provide new insights into the specific functions of integrins during tumor cell invasion.

Lochter, Andre; Navre, Marc; Werb, Zena; Bissell, Mina J




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...


Genetics Home Reference: Mucolipidosis III alpha/beta  


... literature OMIM Genetic disorder catalog Conditions > Mucolipidosis III alpha/beta On this page: Description Genetic changes Inheritance ... definitions Reviewed October 2014 What is mucolipidosis III alpha/beta? Mucolipidosis III alpha/beta is a slowly ...


77 FR 44511 - Airworthiness Directives; Alpha Aviation Concept Limited Airplanes  

Federal Register 2010, 2011, 2012, 2013, 2014

...2120-AA64 Airworthiness Directives; Alpha Aviation Concept Limited Airplanes airworthiness directive (AD) for Alpha Aviation Concept Limited Model R2160 Airplanes...identified in this proposed AD, contact Alpha Aviation, 59 Hautapu Road, RD...



Genetics Home Reference: Mucolipidosis II alpha/beta  


... 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 ...


77 FR 60887 - Airworthiness Directives; Alpha Aviation Concept Limited Airplanes  

Federal Register 2010, 2011, 2012, 2013, 2014

...2120-AA64 Airworthiness Directives; Alpha Aviation Concept Limited Airplanes airworthiness directive (AD) for Alpha Aviation Concept Limited Model R2160 Airplanes...information identified in this AD, contact Alpha Aviation, 59 Hautapu Road, RD 1,...



Who Is at Risk for Alpha-1 Antitrypsin Deficiency?  


... NHLBI on Twitter. Who Is at Risk for Alpha-1 Antitrypsin Deficiency? Alpha-1 antitrypsin (AAT) deficiency occurs in all ethnic ... substances. Rate This Content: Next >> October 11, 2011 Alpha-1 Antitrypsin Deficiency Clinical Trials Clinical trials are ...


What Does It Mean to Be an Alpha-1 Carrier?  


... CSL Behring Talecris Biotherapeutics The mission of the Alpha-1 Foundation is to provide the leadership and ... more information, visit: The Alpha-1 Association is the leading national patient membership ...


A method for creating materials with a desired refraction coefficient  

E-print Network

It is proposed to create materials with a desired refraction coefficient in a bounded domain $D\\subset \\R^3$ by embedding many small balls with constant refraction coefficients into a given material. The number of small balls per unit volume around every point $x\\in D$, i.e., their density distribution, is calculated, as well as the constant refraction coefficients in these balls. Embedding into $D$ small balls with these refraction coefficients according to the calculated density distribution creates in $D$ a material with a desired refraction coefficient.

A. G. Ramm



alpha-Crystallin can Function as a Molecular Chaperone  

Microsoft Academic Search

The alpha-crystallins (alphaA and alphaB) are major lens structural proteins of the vertebrate eye that are related to the small heat shock protein family. In addition, crystallins (especially alphaB) are found in many cells and organs outside the lens, and alphaB is overexpressed in several neurological disorders and in cell lines under stress conditions. Here I show that alpha-crystallin can

Joseph Horwitz



Lucid dreaming and alpha activity: a preliminary report.  


10 good dream recallers spent 2 nights in the sleep lab during which they were awakened 4 times per night from REM sleep, twice during their highest alpha activity in REM, and twice during low REM alpha. 5 were given alpha feedback training prior to sleep onset. Arousals from high alpha REM sleep yielded significantly higher lucidity ratings. Alpha feedback had no effect upon lucidity or REM alpha levels. Similarities between lucid dreams and meditative phenomena are discussed. PMID:7162915

Ogilvie, R D; Hunt, H T; Tyson, P D; Lucescu, M L; Jeakins, D B



Autoregulation of I kappa B alpha activity.  

PubMed Central

Transcription factor NF-kappa B regulates the expression of a plethora of genes. The activity of NF-kappa B proteins is regulated by I kappa B proteins. We report that induction of I kappa B alpha, a member of the I kappa B family of proteins, is preceded by activation of NF-kappa B complex. The promoter of the I kappa B alpha gene contains a kappa B site that is directly involved in its induction by the NF-kappa B complex. Degradation of I kappa B alpha protein precedes activation of NF-kappa B DNA binding activity, whereas newly synthesized I kappa B alpha protein inhibits NF-kappa B activity. If the degradation of I kappa B alpha is prevented, the induction of DNA binding activity of NF-kappa B complex is severely curtailed. These data suggest the existence of an autoregulatory loop whereby I kappa B alpha regulates the activity of transcription factor NF-kappa B, which in turn regulates the I kappa B alpha activity. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:8278379

Chiao, P J; Miyamoto, S; Verma, I M



Alpha-Particle Condensation in Nuclear Systems  

E-print Network

The onset of quartetting, i.e. alpha-particle condensation, in symmetric nuclear matter is studied with the help of an in-medium modified four nucleon equation. It is found that at very low density quartetting wins over pairing, because of the strong binding of the alpha-particles. The critical temperature can reach values up to around 6 MeV. Also the disappearance of alpha-particles with increasing density, i.e. the Mott transition, is investigated. In finite nuclei the Hoyle state, that is the 0_2^+ of 12C, is identified as an "alpha-particle condensate" state. It is conjectured that such states also exist in heavier n alpha-nuclei, like 16O, 20Ne, etc. For instance the 6-th 0^+ state of 16O at 15.1 MeV is identified from a theoretical analysis as being a strong candidate for an alpha condensate state. Exploratory calculations are performed for the density dependence of the alpha condensate fraction at zero temperature to address the suppression of the four-particle condensate below nuclear-matter density. Possible quartet condensation in other systems is discussed briefly

Y. Funaki; T. Yamada; H. Horiuchi; G. Röpke; P. Schuck; A. Tohsaki



Lyman alpha radiation in external galaxies  

NASA Technical Reports Server (NTRS)

The Ly alpha line of atomic hydrogen is often a luminous component of the radiation emitted by distant galaxies. Except for those galaxies which have a substantial central source of non-stellar ionizing radiation, most of the Ly alpha radiation emitted by galaxies is generated within regions of the interstellar medium which are photoionized by starlight. Conversely, much of the energy radiated by photoionized regions is carried by the Ly alpha line. Only hot, massive stars are capable of ionizing hydrogen in the interstellar medium which surrounds them, and because such stars are necessarily short-lived, Ly alpha emission traces regions of active star formation. Researchers argue that the strength of the Ly alpha emission observed from external galaxies may be used to estimate quantitatively the dust content of the emitting region, while the Ly alpha line profile is sensitive to the presence of shock waves. Interstellar dust particles and shock waves are intimately associated with the process of star formation in two senses. First, both dust particles and shock waves owe their existence to stellar activity; second, they may both serve as agents which facilitate the formation of stars, shocks by triggering gravitational instabilities in the interstellar gas that they compress, and dust by shielding star-forming molecular clouds from the ionizing and dissociative effects of external UV radiation. By using Ly alpha observations as a probe of the dust content in diffuse gas at high redshift, we might hope to learn about the earliest epochs of star formation.

Neufeld, David A.; Mckee, Christopher F.



Lyman Alpha Spicule Observatory (LASO)  

NASA Technical Reports Server (NTRS)

The Lyman Alpha Spicule Observatory (LASO) sounding rocket will observe smallscale eruptive events called "Rapid Blue-shifted Events" (RBEs) [Rouppe van der Voort et al., 2009], the on-disk equivalent of Type-II spicules, and extend observations that explore their role in the solar coronal heating problem [De Pontieu et al., 2011]. LASO utilizes a new and novel optical design to simultaneously observe two spatial dimensions at 4.2" spatial resolution (2.1" pixels) over a 2'x2' field of view with high spectral resolution of 66mAngstroms (33mAngstroms pixels) across a broad 20Angstrom spectral window. This spectral window contains three strong chromospheric and transition region emissions and is centered on the strong Hydrogen Lyman-a emission at 1216Angstroms. This instrument makes it possible to obtain new data crucial to the physical understanding of these phenomena and their role in the overall energy and momentum balance from the upper chromosphere to lower corona. LASO was submitted March 2011 in response to the ROSES SHP-LCAS call.

Chamberlin, Phillip C.



Longitudinal and transverse dispersion coefficients in braided rivers.  


The dispersion characteristics of braided rivers are presently unclear. The comprehensive flow structure in a physical braided river model was measured and was used to estimate its dispersion coefficient tensor. The largest values of the longitudinal and transverse dispersion coefficients occurred in the separation zone in two anabranches. The separation zone disappeared in a small diversion angle model of braided rivers where the coefficients were smaller. As for the sectional transverse distribution, the two coefficients varied markedly and an interesting negative correlation between them appeared in several sections. The dispersion coefficients increased with upstream flow rates. Comparison between the coefficients for different anabranch widths revealed higher values in wider sections. Finally, the values of the laboratory tests were compared with those in a real braided river, and relatively larger coefficients were found in natural rivers. The findings of this paper could be helpful in understanding the dispersion characteristics and in estimating pollutant concentration in braided rivers. PMID:25051472

Gu, Li; Jiao, Zinan; Hua, Zulin



Absorbed dose rate conversion coefficients for reference terrestrial biota for external photon and internal exposures.  


The paper describes dosimetric models that allow the estimation of average radiation exposures to terrestrial biota due to environmental sources in the soil as well as internal uniform distributions of radionuclides. Simple three-dimensional phantoms for 13 faunal reference organisms are specified. The calculation of absorbed dose per unit source strength for these targets is based on photon and electron transport simulations using the Monte Carlo method. The presented absorbed dose rate conversion coefficients are derived for terrestrial reference species. This allows the assessment of internal exposure as well as external photon exposure depending on the nuclide, habitat, target size and environmental contamination. To enable the application of specific radiation weighting factors for alpha-, low energy beta- (E0 < 10 keV), beta- and gamma-radiations, their partial contributions to the total absorbed dose are provided separately. The coefficients for external exposure are listed for organisms living above the ground for an infinite plane source 3 mm deep in soil, as well as for a horizontally infinite volume source uniformly distributed to a depth of 10 cm. Furthermore, the coefficients are also presented for organisms living in a contaminated 50 cm thick soil layer. A multi-layer canopy model for plants is also described. The conversion coefficients are given for 3H, 14C, 40K, 36Cl, 59,63Ni, 89,90Sr, 94Nb, 99Tc, 106Ru, 129,131I, 134,135,137Cs, 210Po, 210Pb, 226Ra, 227,228,230,231,232,234Th, 234,235,238U, 238,239,240,241Pu, 241Am, 237Np and 242,243,244Cm, together with their PMID:15700697

Taranenko, V; Pröhl, G; Gómez-Ros, J M



Analytical aerodynamic model of a high alpha research vehicle wind-tunnel model  

NASA Technical Reports Server (NTRS)

A 6 DOF analytical aerodynamic model of a high alpha research vehicle is derived. The derivation is based on wind-tunnel model data valid in the altitude-Mach flight envelope centered at 15,000 ft altitude and 0.6 Mach number with Mach range between 0.3 and 0.9. The analytical models of the aerodynamics coefficients are nonlinear functions of alpha with all control variable and other states fixed. Interpolation is required between the parameterized nonlinear functions. The lift and pitching moment coefficients have unsteady flow parts due to the time range of change of angle-of-attack (alpha dot). The analytical models are plotted and compared with their corresponding wind-tunnel data. Piloted simulated maneuvers of the wind-tunnel model are used to evaluate the analytical model. The maneuvers considered are pitch-ups, 360 degree loaded and unloaded rolls, turn reversals, split S's, and level turns. The evaluation finds that (1) the analytical model is a good representation at Mach 0.6, (2) the longitudinal part is good for the Mach range 0.3 to 0.9, and (3) the lateral part is good for Mach numbers between 0.6 and 0.9. The computer simulations show that the storage requirement of the analytical model is about one tenth that of the wind-tunnel model and it runs twice as fast.

Cao, Jichang; Garrett, Frederick, Jr.; Hoffman, Eric; Stalford, Harold



Glucosylation of alpha-butyl- and alpha-octyl-D-glucopyranosides by dextransucrase and alternansucrase from Leuconostoc mesenteroides.  


For the first time, glucosylation of alpha-butyl- and alpha-octylglucopyranoside was achieved using dextransucrase (DS) of various specificities, and alternansucrase (AS) from Leuconostoc mesenteroides. All the glucansucrases (GS) tested used alpha-butylglucopyranoside as acceptor; in particular, DS produced alpha-D-glucopyranosyl-(1-->6)-O-butyl-alpha-D-glucopyranoside and alpha-D-glucopyranosyl-(1-->6)-alpha-D-glucopyranosyl-(1-->6)-O-butyl-alpha-D-glucopyranoside. In contrast, alpha-octylglucopyranoside was glucosylated only by AS which was shown to be the most efficient catalyst. The conversion rates, obtained with this enzyme at sucrose to acceptor molar ratio of 2:1 reached 81 and 61% for alpha-butylglucopyranoside and alpha-octylglucopyranoside, respectively. Analyses obtained from liquid chromatography coupled with mass spectrometry revealed that different series of alpha-alkylpolyglucopyranosides regioisomers of increasing polymerization degree can be formed depending on the specificity of the catalyst. PMID:12681910

Richard, Gaëtan; Morel, Sandrine; Willemot, René-Marc; Monsan, Pierre; Remaud-Simeon, Magali



Collagen alpha5 and alpha2(IV) chain coexpression: analysis of skin biopsies of Alport patients.  


Alport syndrome is a collagen type IV disease caused by mutations in the COL4A5 gene with the X-linked form being most prevalent. The resultant alpha5(IV) collagen chain is a component of the glomerular and skin basement membranes (SBMs). Immunofluorescent determination of the alpha5(IV) chain in skin biopsies is the procedure of choice to identify patients. In 30% of patients, however, the mutant protein is still found in the SBM resulting in a normal staining pattern. In order to minimize or eliminate false results, we compared the distribution of the alpha2(IV) chain (another SBM component) and the alpha5(IV) chain by standard double label immunofluorescence (IF) and by confocal laser scanning microscopy. The study was performed on 55 skin biopsies of patients suspected of Alports and five normal control specimens. In normal skin, IF showed the classical linear pattern for both collagens along the basement membrane. Additionally, decreased alpha5(IV) was found in the bottom of the dermal papillary basement membrane. Confocal analysis confirmed the results and show alpha5(IV) focal interruptions. In suspected patients, both techniques showed the same rate of abnormal alpha5(IV) expression: segmental in women and absent in men. Our results show a physiological variation of alpha5(IV) location with focal interruptions and decreased expression in the bottom of the dermal basement membrane. Comparison of alpha5(IV) with alpha2(IV) expression is simple and eliminates technical artifacts. PMID:17554254

Patey-Mariaud de Serre, N; Garfa, M; Bessiéres, B; Noël, L H; Knebelmann, B



Fibrinogen {alpha} genes: Conservation of bipartite transcripts and carboxy-terminal-extended {alpha} subunits in vertebrates  

SciTech Connect

All three well-studied subunits of the clotting protein fibrinogen ({alpha}, {beta}, {gamma}) share N-terminal structural homologies, but until recently only the {beta} and {gamma} chains were recognized as having similar globular C-termini. With the discovery of an extra exon in the human fibrinogen {alpha} gene (exon VI), a minor form of the {alpha} subunit ({alpha}{sub E}) with an extended {beta}- and {gamma}-like C-terminus has been identified. In the present study, the polymerase chain reaction has been used to identify sequences that encode counterparts to {alpha}{sub E} in chicken, rabbit, rat, and baboon. The basic six-exon structure of the fibrinogen {alpha} genes is shown to be conserved among mammals and birds, as are the intron positions. Bipartite transcripts - still bearing an intron prior to the last exon - are found among the products of the various vertebrate fibrinogen {alpha} genes. The last exon represents the largest conserved segment of the gene and, in each species examined, encodes exactly 236 amino acids. The C-termini of these {alpha}{sub E} chains align without a single gap and are between 76 and 99% identical. Since the exon VI-encoded domain of {alpha}{sub E} is as well conserved as the corresponding regions of the {beta} and {gamma} chains, it follows that it is equally important and that {alpha}{sub E}-fibrinogen plays a vital, if as-yet unrecognized physiological role. 21 refs., 7 figs., 1 tab.

Fu, Y.; Cao, Y.; Hertzberg, K.M.; Grieninger, G. [Lindsley F. Kimball Research Inst. of the New York Blood Center, NY (United States)] [Lindsley F. Kimball Research Inst. of the New York Blood Center, NY (United States)



Strong absorption model analysis of alpha scattering  

NASA Astrophysics Data System (ADS)

Angular distribution of alpha particles at several energies, E(sub alpha) = 21 approx. 85.6 MeV from a number of nuclei between Ni-20 and Sn-119, extending to wide angular range up to approx. 160 C in some cases, have been analyzed in terms of three-parameter strong absorption model of Frahn and Venter. Interaction radius and surface diffuseness are obtained from the parameter values rendering the best fit to the elastic scattering data. The inelastic scattering of alpha particles from a number of nuclei, leading to quadrupole and octupole excitations has also been studied giving the deformation parameters (beta sub L).

Rahman, M. A.; Chandrapaul, S.; Sengupta, H. M.; Rahman, M.



Alpha cluster structure in 56Ni  

NASA Astrophysics Data System (ADS)

The inelastic ?-scattering experiment on 56Ni in inverse kinematics was performed at an incident energy of 50 MeV/u at GANIL. A very high multiplicity for ?-particle emission was observed with our phase-space limited experimental set-up. The maximum observed multiplicity, which cannot be explained by means of the statistical decay model, amounted to seven. The ideal classical gas model at kT = 3 MeV fairly well reproduced the experimental momentum distribution and multiplicity of alpha particles. This result strongly suggests that an alpha-gas state in 56Ni may be excited via inelastic alpha scattering.

Akimune, H.; Fujiwara, M.; Gibelin, J.; Harakeh, M. N.; Achouri, L.; Bagchi, S.; Bastin, B.; Boretzky, K.; Bouzomita, H.; Caceres, L.; Damoy, S.; Delaunay, F.; Fernández-Domínguez, B.; Caamano, M.; Garg, U.; Grinyer, G. F.; Kalantar-Nayestanaki, N.; Kamalou, O.; Khan, E.; Krasznahorkay, A.; Lhoutellier, G.; Lukyanov, S.; Mazurek, K.; Najafi, M.; Pancin, J.; Penionzkhevich, Y.; Perrot, L.; Raabe, R.; Rigollet, C. E.; Roger, T.; Sambi, S.; Savajols, H.; Senoville, M.; Stodel, C.; Suen, L.; Thomas, J. C.; van de Walle, J.; Vandebrouck, M.



Reliability coefficients of three corneal pachymeters.  


We compared the accuracy and reproducibility of a hand-held portable ultrasound pachymeter, the Pach-Pen (Bio-Rad, Ophthalmic Division, Santa Ana, California); another ultrasound pachymeter, the DGH 1000 (DGH Technology, Inc., Frazer, Pennsylvania); and the Pro-Cem 4 endothelial specular microscope (Alcon-Surgical, Inc., Irvine, California). Each eye of 18 healthy human subjects was examined to determine corneal thickness using the three different instruments. For each instrument, five repeated measurements were obtained at each of five corneal locations (one central, four peripheral), for a total of 25 measurements per eye. The accuracy of the two ultrasound pachymeters was tested by comparing measurements obtained on specially designed test blocks of known thickness. The Pach-Pen was the more accurate of the two ultrasound pachymeters, with measurements within the range of 0.003 to 0.065 mm from the true thickness. The three instruments were most consistent in mean thickness in the center of the cornea. All three instruments showed excellent intraobserver reproducibility, as measured by reliability coefficients over 90%. Overall, the Pach-Pen pachymeter had high reproducibility, and produced more accurate measurements than the DGH 1000 pachymeter. PMID:1598955

Wheeler, N C; Morantes, C M; Kristensen, R M; Pettit, T H; Lee, D A



Attenuation coefficients for water quality trading.  


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



Transport coefficients of soft repulsive particle fluids.  


Molecular dynamics computer simulation has been used to compute the self-diffusion coefficient, D, and shear viscosity, ?(s), of soft-sphere fluids, in which the particles interact through the soft-sphere pair potential, ?(r) = ?(?/r)(n), where n measures the steepness or stiffness of the potential, ? and ? are a characteristic energy and distance, respectively. The simulations were carried out on monodisperse systems for a range of n values from the hard-sphere ([Formula: see text]) limit down to n = 4 over a range of densities. An ideal glass transition value was estimated from the limit where D and [Formula: see text] for each value of n. Nucleation of the crystalline phase was found to intervene prior to the formation of the glass itself, as has been found previously for hard spheres (i.e. [Formula: see text]). With increasing softness the glass transition moves further within the solid part of the phase diagram, as predicted by Cardenas and Tosi (2005 Phys. Lett. A 336 423), although the volume fractions at the glass transition estimated by the current procedure here are systematically lower than the predictions of that study. PMID:21694216

Heyes, D M; Bra?ka, A C



Tumor necrosis factor alpha inhibits collagen alpha 1(I) gene expression in rat hepatic stellate cells through a G protein  

Microsoft Academic Search

BACKGROUND & AIMS: Tumor necrosis factor alpha (TNF-alpha) inhibits collagen gene expression in cultured fibroblasts. By binding to cell surface receptors, TNF-alpha promotes signals within the cells. The purpose of this study was to investigate the role played by G proteins in TNF-alpha-induced inhibition of collagen gene expression.METHODS: Effect of TNF-alpha on collagen alpha 1(I) messenger RNA (mRNA) level was

I Hernandez-Munoz; P de la Torre; JA Sanchez-Alcazar; I Garcia; E Santiago; MT Munoz-Yague; JA Solis-Herruzo



Thermodynamic studies of molecular interactions in aqueous alpha-cyclodextrin solutions: application of McMillan-Mayer and Kirkwood-Buff theories.  


Osmotic vapor pressure and density measurements were made for aqueous alpha-cyclodextrin (alpha-CD) solutions in the temperature range between 293.15 and 313.15 K. The experimental osmotic coefficient data were used to determine the corresponding activity coefficients and the excess Gibbs free energy of solutions. Further, the activity data obtained at different temperatures along with the enthalpies of dissolution (reported in the literature) were processed to obtain the excess enthalpy and excess entropy values for the solution process. The partial molar entropies of water and of alpha-cyclodextrin were calculated at different temperatures and also at different concentrations of alpha-CD. Using the partial molar volume data at infinite dilution, the solute-solvent cluster integrals were evaluated which yielded information about solute-solvent interactions. The application of McMillan-Mayer theory of solutions was made to obtain osmotic second and third virial coefficients which were decomposed into attractive and repulsive contributions to solute-solute interactions. The second and third osmotic virial coefficients are positive and show minimum at 303.15 K. The Kirkwood-Buff (KB) integrals G(ij), defined by the equation G(ij) = f(infinity)0 (g(ij)- 1)4pir(2) dr, have been evaluated using the experimental osmotic coefficient (and hence activity coefficient) and partial molar volume data. The limiting values of KB integrals, G(ij)(0) are compared with molecular interaction parameters (solute-solute i.e., osmotic second virial coefficient) obtained using McMillan-Mayer theory of solutions. We found an excellent agreement between the two approaches. PMID:16970487

Terdale, Santosh S; Dagade, Dilip H; Patil, Kesharsingh J



Transport of alpha- and beta-D-glucose by the intact human red cell  

SciTech Connect

The kinetics of alpha- and beta-D-glucose mutarotation and the transport of these anomers by intact human red cells were determined at 0.6 and 36.6 degrees C. The mutarotation coefficients for alpha- and beta-D-glucose in cell-free tris(hydroxymethyl)aminomethane medium (pH 7.4) at 0.6 degrees C are (2.25 +/- 0.2) and (1.73 +/- 0.42) X 10(-3) min-1, respectively, and at 36.6 degrees C are (69 +/- 12) and (75 +/- 5) X 10(-3) min-1, respectively. These values are in good agreement with previous estimates. At 0.6 degrees C, the red cell contains no detectable mutarotase activity. Initial rates of sugar uptake were measured by using radiolabeled D-glucose and time courses of uptake by turbidimetry. The time courses of alpha- and beta-D-glucose and an equilibrium mixture of alpha- and beta-D-glucose infinite-cis entry are identical at 0.66 degrees C (n = 41) where negligible mutarotation is observed. The apparent Ki values for inhibition of radiolabeled D-glucose initial uptake by unlabeled alpha- or beta-D-glucose at 0.6 degrees C are identical (1.6 mM). The calculated Vmax parameters for uptake of the radiolabeled anomers at this temperature are also indistinguishable. The time courses of infinite-cis alpha- and beta-D-glucose uptake at 36.66 degrees C are identical (n = 40). While D-glucose mutarotation is more rapid at this temperature, the anomers of D-glucose are not transported differently by the red cell hexose transfer system.

Carruthers, A.; Melchior, D.L.



Convex and alpha-prestarlike subordination chains  

NASA Astrophysics Data System (ADS)

In this paper we consider convex subordination chains (c.s.c.) and alpha-prestarlike subordination chains ([alpha]-p.s.c.) over (0,1] on the unit disc in the complex plane. We obtain sufficient conditions for a mapping f(z,t) to be an [alpha]-p.s.c. over (0,1], which generalize a well-known result of Ruscheweyh [St. Ruscheweyh, Convolutions in Geometric Function Theory, Les Presses de l'Universite de Montreal, 1982]. We also obtain sufficient conditions for injectivity for nonanalytic mappings on the unit disc, and give certain examples of [alpha]-c.s.c. over (0,1] on the unit disc.

Kohr, Gabriela; Mocanu, Petru T.; Serb, Ioan



Radioimmunotherapy with alpha-particle emitting radionuclides.  


An important consideration in the development of effective strategies for radioimmunotherapy is the nature of the radiation emitted by the radionuclide. Radionuclides decaying by the emission of alpha-particles offer the possibility of matching the cell specific reactivity of monoclonal antibodies with radiation with a range of only a few cell diameters. Furthermore, alpha-particles have important biological advantages compared with external beam radiation and beta-particles including a higher biological effectiveness, which is nearly independent of oxygen concentration, dose rate and cell cycle position. In this review, the clinical settings most likely to benefit from alpha-particle radioimmunotherapy will be discussed. The current status of preclinical and clinical research with antibodies labeled with 3 promising alpha-particle emitting radionuclides - (213)Bi, (225)Ac, and (211)At - also will be summarized. PMID:15640792

Zalutsky, M R; Pozzi, O R



Nuclear diagnostic for fast alpha particles  


This invention relates generally to high energy confined plasmas and more particularly is directed to measuring the velocity distribution of confined energetic alpha particles resulting from deuterium-tritium fusion reactions in a confined energetic plasma.

Grisham, L.R.; Post, D.E. Jr.; Dawson, J.M.



alpha-Picoline from Rumex obtusifolius L  

Microsoft Academic Search

alpha-PICOLINE has been isolated from the leaves of the dock, Rumex obtusifolius L. There are isolated instances where pyridine and simple derivatives have been found to occur in Nature, for example, pyridine in Aplopappus hartwegi1 and 3-methoxypyridine in Equisetum arvense2. This would appear to be the first record of the presence of alpha-picoline in a natural source. The base was

S. Wilkinson



Measurement of the angle alpha at BABAR  

SciTech Connect

The authors present recent measurements of the CKM angle {alpha} using data collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at the SLAC National Accelerator Laboratory, operating at the {Upsilon}(4S) resonance. They present constraints on {alpha} from B {yields} {pi}{pi}, B {yields} {rho}{rho} and B {yields} {rho}{pi} decays.

Perez, A.; /Orsay, LAL



Alpha particle haloes in chlorite and cordierite  

Microsoft Academic Search

Summary  Effects of the impact of natural long-term irradiation with alpha particles in one chamosite and one cordierite sample were\\u000a characterised in detail using electron microprobe, Raman microprobe, optical absorption spectroscopy (cordierite only), and\\u000a transmission electron microscopy (TEM; cordierite only) analysis. In both cases, the impact of 4He cores (alpha particles) that were emitted from actinide-bearing mineral inclusions has caused the

L. Nasdala; M. Wildner; R. Wirth; N. Groschopf; D. C. Pal; A. Möller



Alpha-emitters for medical therapy workshop  

SciTech Connect

A workshop on ``Alpha-Emitters for Medical Therapy`` was held May 30-31, 1996 in Denver Colorado to identify research goals and potential clinical needs for applying alpha-particle emitters and to provide DOE with sufficient information for future planning. The workshop was attended by 36 participants representing radiooncology, nuclear medicine, immunotherapy, radiobiology, molecular biology, biochemistry, radiopharmaceutical chemistry, dosimetry, and physics. This report provides a summary of the key points and recommendations arrived at during the conference.

Feinendegen, L.E.; McClure, J.J.



Measurement system for alpha emitters in solution  

NASA Astrophysics Data System (ADS)

The measurement of alpha emitter concentrations in solution corresponds to a need felt in particular by laboratories working on actinides and in the spent fuel reprocessing industry. The instrument present here allows this measurement continuously by the use of a new scintillator that is insensitive to corrosive liquids. The extreme thinness of the scintillator guarantees good detection selectivity of alpha particles in the presence of beta and gamma emissions. Examples of uranium-233, plutonium-239 and americium-241 concentration measurements are presented.

Robert, A.; Sella, C.; Heindl, R.



alpha-Manganese Phases containing Technetium99  

Microsoft Academic Search

THE existence of alpha-manganese phases in the zirconium-technetium, niobium-technetium and molybdenum-technetium systems was recently reported by V. B. Compton et al.1. During the course of our investigation of alloy phases involving technetium-99 with transition metals, alpha-manganese phases were found in the binary systems scandium-technetium, titanium-technetium, hafnium-technetium and tantalum-technetium. Pertinent information is given in Table 1. The alloys were made by

D. J. Lam; J. B. Darby; J. W. Downey; L. J. Norton



Transport of Radioactive Material by Alpha Recoil  

SciTech Connect

The movement of high-specific-activity radioactive particles (i.e., alpha recoil) has been observed and studied since the early 1900s. These studies have been motivated by concerns about containment of radioactivity and the protection of human health. Additionally, studies have investigated the potential advantage of alpha recoil to effect separations of various isotopes. This report provides a review of the observations and results of a number of the studies.

Icenhour, A.S.



?-cluster asymptotic normalization coefficients for nuclear astrophysics  

NASA Astrophysics Data System (ADS)

Background: Many important ?-particle induced reactions for nuclear astrophysics may only be measured using indirect techniques due to the small cross sections at the energy of interest. One such indirect technique is to determine the asymptotic normalization coefficients (ANCs) for near-threshold resonances extracted from sub-Coulomb ?-transfer reactions. This approach provides a very valuable tool for studies of astrophysically important reaction rates since the results are practically model independent. However, the validity of the method has not been directly verified. Purpose: The aim of this Rapid Communication is to verify the technique using the O16(Li6,d)Ne20 reaction as a benchmark. The Ne20 nucleus has a well-known 1- state at an excitation energy of 5.79 MeV with a width of 28 eV. Reproducing the known value with this technique is an ideal opportunity to verify the method. Method: The 1- state at 5.79 MeV is studied using the ?-transfer reaction O16(Li6,d)Ne20 at sub-Coulomb energies. Results: The partial ? width for the 1- state at excitation energy of 5.79 MeV is extracted and compared with the known value, allowing the accuracy of the method to be evaluated. Conclusions: This study demonstrates that extracting the ANCs using sub-Coulomb ?-transfer reactions is a powerful tool that can be used to determine the partial ? width of near-threshold states that may dominate astrophysically important nuclear reaction rates.

Avila, M. L.; Rogachev, G. V.; Koshchiy, E.; Baby, L. T.; Belarge, J.; Kemper, K. W.; Kuchera, A. N.; Santiago-Gonzalez, D.



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 , which is the ratio of the solid solubility to liquid solubility. A knowledge of 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 (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 using MTDATA are presented for 170 binary systems. In total, the combined values of from all available sources for 430 binary systems are presented. In addition, by considering all available values of for impurities in 25 different metal solvents (1300 binary systems) enough data are available to characterize patterns in the value of for a given impurity as a function of its position in the periodic table. This enables prediction of for a significant number of binary systems for which data and calculations are unavailable. By combining data from many sources, values of 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.



THE ALPHA SPECTRUM FROM ($gamma$,\\/cap alpha\\/) ON V⁵¹  

Microsoft Academic Search

The alpha -spectra from V⁵¹( gamma , alpha )Sc⁴⁷ are shown ; for 21 and 30 Mev end point betatron energies. Assuming an isotropic angular ; distribution for emitted alphas, total integrated cross sections of 2,4(1 plus ; or minus 0.3) and 6(1 plus or minus 0.3) mb Mev were obtained for 21 and 30 ; Mev energies, respectively. The

M. Kregar; B. Povh



Energy dependence of event shapes and of $\\\\alpha_s$ at LEP 2  

Microsoft Academic Search

Infrared and collinear safe event shape distributions and their mean values are determined using the data taken at ve di erent centre of mass energies above $M_Z$ with the DELPHI detector at LEP. From the event shapes, the strong coupling $\\\\alpha_s$ is extracted in $O(\\\\alpha^2_s)$, NLLA and a combined scheme using hadronisation corrections evaluated with fragmentation model generators as well

P. Abreu; W Adam; T Adye; P Adzic; Z Albrecht; T Alderweireld; G D Alekseev; R Alemany; T Allmendinger; P P Allport; S Almehed; Ugo Amaldi; N Amapane; S Amato; E G Anassontzis; P Andersson; A Andreazza; S Andringa; P Antilogus; W D Apel; Y Arnoud; B Åsman; J E Augustin; A Augustinus; Paul Baillon; P Bambade; F Barão; Guido Barbiellini; R Barbier; Dimitri Yuri Bardin; G Barker; A Baroncelli; Marco Battaglia; M Baubillier; K H Becks; M Begalli; A Behrmann; P Beillière; Yu A Belokopytov; K S Belous; N C Benekos; Alberto C Benvenuti; C Bérat; M Berggren; D Bertini; D Bertrand; M Besançon; F Bianchi; M Bigi; S M Bilenky; M A Bizouard; D Bloch; H M Blom; M Bonesini; W Bonivento; M Boonekamp; P S L Booth; A W Borgland; G Borisov; C Bosio; O Botner; E Boudinov; B Bouquet; C Bourdarios; T J V Bowcock; I Boyko; I Bozovic; M Bozzo; P Branchini; T Brenke; R A Brenner; P Brückman; J M Brunet; L Bugge; T Buran; T Burgsmüller; Brigitte Buschbeck; P Buschmann; S Cabrera; M Caccia; M Calvi; T Camporesi; V Canale; F Carena; L Carroll; Carlo Caso; M V Castillo-Gimenez; A Cattai; F R Cavallo; V Chabaud; M M Chapkin; P Charpentier; L Chaussard; P Checchia; G A Chelkov; R Chierici; P V Chliapnikov; P Chochula; V Chorowicz; J Chudoba; K Cieslik; P Collins; R Contri; E Cortina; G Cosme; F Cossutti; J H Cowell; H B Crawley; D J Crennell; S Crépé; G Crosetti; J Cuevas-Maestro; S Czellar; Martyn Davenport; W Da Silva; A Deghorain; G Della Ricca; P A Delpierre; N Demaria; A De Angelis; Wim de Boer; C De Clercq; B De Lotto; A De Min; L S De Paula; H Dijkstra; Lucia Di Ciaccio; J Dolbeau; K Doroba; M Dracos; J Drees; M Dris; A Duperrin; J D Durand; G Eigen; T J C Ekelöf; Gösta Ekspong; M Ellert; M Elsing; J P Engel; B Erzen; M C Espirito-Santo; E Falk; G K Fanourakis; D Fassouliotis; J Fayot; Michael Feindt; A Fenyuk; P Ferrari; A Ferrer; E Ferrer-Ribas; F Ferro; S Fichet; A Firestone; U Flagmeyer; H Föth; E Fokitis; F Fontanelli; B J Franek; A G Frodesen; R Frühwirth; F Fulda-Quenzer; J A Fuster; A Galloni; D Gamba; S Gamblin; M Gandelman; C García; C Gaspar; M Gaspar; U Gasparini; P Gavillet; E N Gazis; D Gelé; N Ghodbane; I Gil; F Glege; R Gokieli; B Golob; G Gómez-Ceballos; P Gonçalves; I González-Caballero; Gian P Gopal; L Gorn; M Górski; Yu Guz; Valerio Gracco; J Grahl; E Graziani; C Green; H J Grimm; P Gris; G Grosdidier; K Grzelak; M Günther; J Guy; F Hahn; S Hahn; S Haider; A Hallgren; K Hamacher; J Hansen; F J Harris; V Hedberg; S Heising; J J Hernández; P Herquet; H Herr; T L Hessing; J M Heuser; E Higón; S O Holmgren; P J Holt; S Hoorelbeke; M A Houlden; Josef Hrubec; K Huet; G J Hughes; K Hultqvist; J N Jackson; R Jacobsson; P Jalocha; R Janik; C Jarlskog; G Jarlskog; P Jarry; B Jean-Marie; E K Johansson; P E Jönsson; C Joram; P Juillot; F Kapusta; K Karafasoulis; S Katsanevas; E C Katsoufis; R Keränen; Borut P Kersevan; B A Khomenko; N N Khovanskii; A P Kiiskinen; B J King; A Kinvig; N J Kjaer; O Klapp; H Klein; P M Kluit; P Kokkinias; M Koratzinos; V Kostyukhin; C Kourkoumelis; O Kuznetsov; Manfred Krammer; E Kriznic; J Krstic; Z Krumshtein; P Kubinec; J Kurowska; K L Kurvinen; J Lamsa; P Langefeld; V Lapin; J P Laugier; R Lauhakangas; Gerhard Leder; F Ledroit; V Lefébure; L Leinonen; A Leisos; R Leitner; J Lemonne; Georg Lenzen; V Lepeltier; T Lesiak; M Lethuillier; J Libby; D Liko; A Lipniacka; I Lippi; B Lörstad; J G Loken; J H Lopes; J M López; R López-Fernandez; D Loukas; P Lutz; L Lyons; J N MacNaughton; J R Mahon; A Maio; A Malek; T G M Malmgren; S Maltezos; V Malychev; F Mandl; J Marco; R P Marco; B Maréchal; M Margoni; J C Marin; C Mariotti; A Markou; C Martínez-Rivero; F Martínez-Vidal; S Martí i García; N Mastroyiannopoulos; F Matorras; C Matteuzzi; Giorgio Matthiae; J Masik; F Mazzucato; M Mazzucato; M L McCubbin; R McKay; R McNulty; G McPherson; C Meroni; W T Meyer; E Migliore; L Mirabito; Winfried A Mitaroff; U Mjörnmark; T Moa; M Moch; R Møller; K Mönig; M R Monge; X Moreau; P Morettini; G A Morton; U Müller; K Münich; M Mulders; C Mulet-Marquis; R Muresan; W J Murray; B Muryn; Gerald Myatt; T Myklebust; F Naraghi; M Nassiakou; Francesco Luigi Navarria; S Navas; K Nawrocki; P Negri; S Némécek; N Neufeld; N Neumeister; R Nicolaidou; B S Nielsen; M Nikolenko; V P Nomokonov; Ainsley Normand; A Nygren; V F Obraztsov; A G Olshevskii; A Onofre; Risto Orava; G Orazi; K Österberg; A Ouraou; M Paganoni; S Paiano; R Pain; R Paiva; J Palacios; H Palka; T D Papadopoulou; K Papageorgiou; L Pape; C Parkes; F Parodi; U Parzefall; A Passeri; O Passon; M Pegoraro; L Peralta; Manfred Pernicka; A Perrotta; C Petridou; A Petrolini; H T Phillips; F Pierre; M Pimenta; E Piotto; T Podobnik; M E Pol; G Polok; P Poropat; V Pozdnyakov; P Privitera; N Pukhaeva; Antonio Pullia; D Radojicic; S Ragazzi; H Rahmani; P N Ratoff; A L Read; P Rebecchi; N G Redaelli; Meinhard Regler; D Reid



Phase transition induced by lithium insertion in alphaI- and alphaII-VOPO4  

Microsoft Academic Search

Lithium insertion in alphaI-VOPO4 and alphaII-VOPO4, either by chemical or electrochemical route, leads to the same new compound: alphaI-LiVOPO4 (space group P4\\/nmm). The structure, resolved by neutron and synchrotron diffraction, is made up of planes of corner-connected PO4 and VO5 polyhedra, whereas lithium atoms are located between the layers. The reversal of the short vanadyl bond that corresponds to the

N. Dupré; G. Wallez; J. Gaubicher; M. Quarton



Temperature Dependence of Ionization Coefficients for InP and 1.3 mum InGaAsP Avalanche Photodiodes  

Microsoft Academic Search

Investigations were made on the temperature dependence of excess noise characteristics for InP and 1.3 mum InGaAsP APDs for the case where electrons are injected into the high field region. The effective ratio of the ionization coefficients Keff(beta\\/alpha) was found to decrease with decreasing temperature for both APDs. Theoretical investigations on hot carriers are combined with McIntyre's theory for the

Yoshifumi Takanashi; Yoshiji Horikoshi



{alpha}-states in de Sitter space  

SciTech Connect

Field theory in de Sitter space admits a one-parameter family of vacua determined by a superselection parameter {alpha}. Of these vacua, the Euclidean vacuum uniquely extrapolates to the vacuum of flat Minkowski space. States which resemble the {alpha}-vacua can be constructed as excitations above the Euclidean vacuum. Such states have modes {alpha}(k) which decay faster that k{sup (1-d)/2}. Fields in such states exhibit nonlocal correlations when examined from the perspective of fields in the Euclidean vacuum. The dynamics of such entangled states are fully consistent. If an {alpha}-state with properties that interpolate between an {alpha}-vacuum and the Euclidean vacuum were the initial condition for inflation, a signature for this may be found in a momentum dependent correction to the inflationary power spectrum. The functional formalism, which provides the tool for examining physics in an {alpha}-state, extends to fields of other spin. In particular, the extension to spin-2 may proffer a new class of infrared modifications to gravitational interactions. The implications of superselection sectors for the landscape of string vacua are briefly discussed.

Boer, Jan de [Instituut voor Theoretische Fysica, Valckenierstraat 65, 1018XE Amsterdam (Netherlands); Jejjala, Vishnu; Minic, Djordje [Institute for Particle Physics and Astrophysics, Physics Department, Robeson Hall, Virginia Tech, Blacksburg, Virginia 24061 (United States)



Alpha-dispersion in human tissue  

NASA Astrophysics Data System (ADS)

Beta dispersion is found in living tissue in the kilohertz - megahertz range and is caused by the cellular structure of biological materials with low frequency properties caused by cell membranes. Alpha dispersion is found in the hertz range and the causes are not so well known. Alpha dispersions are the first to disappear when tissue dies. Tissue data have often been based upon excised specimen from animals and are therefore not necessarily representative for human tissue alpha dispersions. Here we present data obtained with non-invasive skin surface electrodes for different segments of the living human body. We found alpha dispersions in all cases; the ankle-wrist results had the smallest. Large alpha dispersions were found where the distance between the electrodes and muscle masses was small, e.g. on the calf. Further studies on electrode technique and reciprocity, electrode positioning, statistical variations, gender, age and bodily constitutions are necessary in order to reveal more about the alpha dispersion, its appearance and disappearance.

Grimnes, Sverre; Martinsen, Ørjan G.



Folding model analysis of alpha radioactivity  

E-print Network

Radioactive decay of nuclei via emission of $\\alpha$ particles has been studied theoretically in the framework of a superasymmetric fission model using the double folding (DF) procedure for obtaining the $\\alpha$-nucleus interaction potential. The DF nuclear potential has been obtained by folding in the density distribution functions of the $\\alpha$ nucleus and the daughter nucleus with a realistic effective interaction. The M3Y effective interaction has been used for calculating the nuclear interaction potential which has been supplemented by a zero-range pseudo-potential for exchange along with the density dependence. The nuclear microscopic $\\alpha$-nucleus potential thus obtained has been used along with the Coulomb interaction potential to calculate the action integral within the WKB approximation. This subsequently yields microscopic calculations for the half lives of $\\alpha$ decays of nuclei. The density dependence and the exchange effects have not been found to be very significant. These calculations provide reasonable estimates for the lifetimes of $\\alpha$ radioactivity of nuclei.

D. N. Basu



Methods for the synthesis and polymerization of .alpha.,.alpha.'-dihalo-p-xylenes  


The present invention describes an improved method for the polymerization of .alpha.,.alpha.-dihalo-p-xylene's such as the .alpha.,.alpha.'-dihalo-2-methoxy-5-(2-ethylhexyloxy)-xylene's. The procedure for synthesis is based on the specific order of addition of reagents and the use of an anionic initiator that allows control of the molecular weight of the polymer. The molecular weight control allows processability of the polymer which is important for its utility in applications including in light-emitting-diodes, field effect transistors and photovoltaic devices.

Ferraris, John P. (Coppell, TX); Neef, Charles J. (Garland, TX)



Measuring Health Related Quality of Life (Hrqol) in Renal Transplant Patients: Psychometric Properties and Cross-Cultural Adaptation of Kidney Transplant Questionnaire (Ktq-25) in Persian  

PubMed Central

Background Different measuring tools have been used to understand the outcomes of renal replacement therapies. The goal of renal transplantation is both to ensure survival, and to promote quality of life in the patients. One of the widely used disease-specific instruments to measure the quality of life is the Kidney Transplant Questionnaire (KTQ-25). Objectives The current study aimed to perform a cross-cultural adaptation and assess the psychometric properties of the KTQ-25 to Persian. Materials and Methods The KTQ-25 was trasnlated according to International Quality of Life Assessment (IQOLA) translation methodology. Cronbach’s alpha coefficient, and test-re-test were used to determine internal consistency, and reliability respectively. Results In the test–re-test reliability of all questionnaire items, Pearson correlation was r = 0.96 (P < 0.001). Cronbach’s alpha coefficient estimated the internal consistency for each scale andalpha equal or more than 0.73 was considered satisfactory. Criterion-related validity, measured by the correlation coefficients between the KTQ-25 and the SF-36 Health Survey, was r = 0.63 (P < 0.001). Conclusions The psychometric properties of the Kidney Transplant Questionnaire (KTQ-25) in Persian have proven to be satisfactory, therefore the application of this questionnaire in clinical practice can be recommended. PMID:23573502

Tayyebi, Ali; Raiesifar, Afsaneh; Najafi Mehri, Soheil; Ebadi, Abbas; Einolahi, Behzad; Pashandi, Shadi



Analytic Forms of the Perpendicular Diffusion Coefficient in NRMHD Turbulence  

NASA Astrophysics Data System (ADS)

In the past different analytic limits for the perpendicular diffusion coefficient of energetic particles interacting with magnetic turbulence were discussed. These different limits or cases correspond to different transport modes describing how the particles are diffusing across the large-scale magnetic field. In the current paper we describe a new transport regime by considering the model of noisy reduced magnetohydrodynamic turbulence. We derive different analytic forms of the perpendicular diffusion coefficient, and while we do this, we focus on the aforementioned new transport mode. We show that for this turbulence model a small perpendicular diffusion coefficient can be obtained so that the latter diffusion coefficient is more than hundred times smaller than the parallel diffusion coefficient. This result is relevant to explain observations in the solar system where such small perpendicular diffusion coefficients have been reported.

Shalchi, A.



Calculation and application of combined diffusion coefficients in thermal plasmas  

NASA Astrophysics Data System (ADS)

The combined diffusion coefficient method is widely used to treat the mixing and demixing of different plasma gases and vapours in thermal plasmas, such as welding arcs and plasma jets. It greatly simplifies the treatment of diffusion for many gas mixtures without sacrificing accuracy. Here, three subjects that are important in the implementation of the combined diffusion coefficient method are considered. First, it is shown that different expressions for the combined diffusion coefficients, arising from different definitions for the stoichiometric coefficients that assign the electrons to the two gases, are equivalent. Second, an approach is presented for calculating certain partial differential terms in the combined temperature and pressure diffusion coefficients that can cause difficulties. Finally, a method for applying the combined diffusion coefficients in computational models, which typically require diffusion to be expressed in terms of mass fraction gradients, is given.

Murphy, Anthony B.



Calculation and application of combined diffusion coefficients in thermal plasmas.  


The combined diffusion coefficient method is widely used to treat the mixing and demixing of different plasma gases and vapours in thermal plasmas, such as welding arcs and plasma jets. It greatly simplifies the treatment of diffusion for many gas mixtures without sacrificing accuracy. Here, three subjects that are important in the implementation of the combined diffusion coefficient method are considered. First, it is shown that different expressions for the combined diffusion coefficients, arising from different definitions for the stoichiometric coefficients that assign the electrons to the two gases, are equivalent. Second, an approach is presented for calculating certain partial differential terms in the combined temperature and pressure diffusion coefficients that can cause difficulties. Finally, a method for applying the combined diffusion coefficients in computational models, which typically require diffusion to be expressed in terms of mass fraction gradients, is given. PMID:24603457

Murphy, Anthony B





Dose conversion coefficients for radionuclides are useful for routine calculations in radiation protection in industry, medicine and research. They give a simple and often sufficient estimate of dose rates during production, handling and storage of radionuclide sources, based solely on the source's activity. The latest compilation of such conversion coefficients dates from 20 y ago, based on nuclear decay data published 30 y ago. The present publication provides radionuclide-specific conversion coefficients to personal dose based on the most recent evaluations of nuclear decay data for 1252 radionuclides and fluence-to-dose-equivalent conversion coefficients for monoenergetic radiations. It contains previously unknown conversion coefficients for >400 nuclides and corrects those conversion coefficients that were based on erroneous decay schemes. For the first time, estimates for the protection quantity Hp(3) are included. PMID:25349458

Otto, Thomas



Anomalies of piezoelectric coefficients in barium titanate thin films  

NASA Astrophysics Data System (ADS)

Modeling of electromechanical devices involves the use of different material coefficients, whose measurement is a difficult task, especially when the problem concerns thin films. Required coefficients of thin films could be found theoretically, using known values of the bulk constants. Electromechanical coefficients of barium titanate thin films are still unknown; therefore, it is expedient to carry out their calculations. We give here the full set of electromechanical coefficients of barium titanate thin films for the whole range of technologically available misfit strains. In the present paper, piezoelectric coefficients as functions of a misfit strain were calculated. It was revealed that piezoelectric coefficients exhibit anomalies at phase boundaries and inside the monoclinic r-phase as well. The obtained results allow finding the required values of the thin-film parameters, varying the misfit strain.

Shirokov, Vladimir; Kalinchuk, Valery; Shakhovoy, Roman; Yuzyuk, Yury



Calculation and application of combined diffusion coefficients in thermal plasmas  

PubMed Central

The combined diffusion coefficient method is widely used to treat the mixing and demixing of different plasma gases and vapours in thermal plasmas, such as welding arcs and plasma jets. It greatly simplifies the treatment of diffusion for many gas mixtures without sacrificing accuracy. Here, three subjects that are important in the implementation of the combined diffusion coefficient method are considered. First, it is shown that different expressions for the combined diffusion coefficients, arising from different definitions for the stoichiometric coefficients that assign the electrons to the two gases, are equivalent. Second, an approach is presented for calculating certain partial differential terms in the combined temperature and pressure diffusion coefficients that can cause difficulties. Finally, a method for applying the combined diffusion coefficients in computational models, which typically require diffusion to be expressed in terms of mass fraction gradients, is given. PMID:24603457

Murphy, Anthony B.



Coefficient of Friction between Tool and Material in Shearing  

NASA Astrophysics Data System (ADS)

In this study, we propose a method of determining the coefficient of friction between a tool flank and a sheared surface in shearing. In this method, the vertical force and horizontal force need to be measured after completion of the separation process, after which the coefficient of friction is defined as the ratio of vertical force to horizontal force. In this study, the influences of punch speed, kinematic viscosity of lubricating oil and clearance on the coefficient of friction were investigated. Using the proposed method, a coefficient of friction of about 0.35 was obtained when ordinary lubricating oil was used. The coefficient of friction between the tool face and the material surface was also determined from sliding friction tests. The results of Finite Element Method taking into account the coefficients of friction obtained by the method showed good agreement with experimental results for the piercing of small holes.

Sasada, Masahiro; Shimura, Kazuki; Aoki, Isamu


Dependence of the GABAA receptor gating kinetics on the alpha-subunit isoform: implications for structure-function relations and synaptic transmission.  

PubMed Central

1. To examine the dependence of gamma-aminobutyric acid (GABAA) receptor gating on the alpha-subunit isoform, we studied the kinetics of GABA-gated currents (IGABA) of receptors that differed in the alpha-subunit subtype, alpha 1 beta 2 gamma 2S and alpha 3 beta 2 gamma 2S. cDNAs encoding rat brain subunits were co-expressed heterologously in HEK-293 cells and the resultant receptors studied with the whole-cell patch clamp technique and rapidly applied GABA pulses (5-10 s). 2. IGABA of both receptors showed a loosely similar dependence on GABA concentration over a wide range (1-5000 microM). Generally, IGABA manifested activation reaching an early current peak, subsequent slower spontaneous desensitization, and deactivation of open channels at pulse termination. Lowering GABA concentrations reduced peak currents and slowed activation and desensitization kinetics. 3. The presence of alpha 3 altered the peak IGABA concentration-response relationship by shifting the fitted Hill equation to tenfold greater GABA concentrations (GABA concentration at half amplitude: alpha 1, 7 microM; and alpha 3, 75 microM) without affecting Hill coefficients (alpha 1, 1.6; alpha 3, 1.5). These findings indicate a reduction in the apparent activating site affinity and are consistent with previous reports. 4. To investigate differences in gating, we normalized for apparent activating site affinities by analysing the time course of macroscopic gating at equi-activating GABA concentrations. The presence of alpha 3 slowed activation fourfold (time to current peak (means +/- S.E.M.): alpha 1, 1.2 +/- 0.06 s (2 microM); alpha 3, 4.7 +/- 0.5 s (20 microM)), desensitization nearly twofold (reciprocal of time to 80% decay: alpha 1, 2.5 +/- 0.48 s-1 (100 microM); alpha 3, 1.5 +/- 0.15 s-1 (1000 microM)) and deactivation threefold (monoexponential decay time constant: alpha 1, 0.22 +/- 0.026 s (2 microM); alpha 3, 0.68 +/- 0.1 s (20 microM)). 5. To gain an insight into the gating mechanisms underlying macroscopic desensitization, we extended a previous gating model of GABAA receptor single-channel activity to include a desensitization pathway. Such a mechanism reproduced empirical alpha 1 beta 2 gamma 2S activation, desensitization and deactivation kinetics. 6. To identify molecular transitions underlying the gating differences between alpha 1 beta 2 gamma 2S and alpha 3 beta 2 gamma 2S receptors, we explored parameter alterations of the alpha 1 beta 2 gamma 2S gating model that provided an accounting of alpha 3 beta 2 gamma 2S empirical responses. Remarkably, alteration of rates and rate constants involved in ligand binding alone allowed reproduction of alpha 3 beta 2 gamma 2S activation, desensitization and deactivation. 7. These results indicate that substitution of the alpha 3 subunit variant in an alpha 1 beta 2 gamma 2S receptor alters transition rates involved in ligand binding that underlie changes in apparent activating site affinity and macroscopic current gating. Furthermore, they argue strongly that the structural determinants of these functional features reside on the alpha-subunit. PMID:8847645

Gingrich, K J; Roberts, W A; Kass, R S



Local linear estimator for stochastic differential equations driven by $\\alpha$-stable L\\'{e}vy motions  

E-print Network

We study the local linear estimator for the drift coefficient of stochastic differential equations driven by $\\alpha$-stable L\\'{e}vy motions observed at discrete instants letting $T \\rightarrow \\infty$. Under regular conditions, we derive the weak consistency and central limit theorem of the estimator. Compare with Nadaraya-Watson estimator, the local linear estimator has a bias reduction whether kernel function is symmetric or not under different schemes.

Yu-Ping, Song



Staphylococcal alpha -toxin: Oligomerization of Hydrophilic Monomers to Form Amphiphilic Hexamers Induced through Contact with Deoxycholate Detergent Micelles  

Microsoft Academic Search

Native staphylococcus aureus alpha -toxin is secreted as a hydrophilic polypeptide chain of Mr 34,000. The presence of deoxycholate above the critical micellar concentration induced the toxin monomers to self-associate, forming ring or cylindrical oligomers. The oligomers were amphiphilic and bound detergent. In deoxycholate solution, the protein-detergent complexes exhibited a sedimentation coefficient of 10.4 S. A Mr of 238,700 was

Sucharit Bhakdi; Roswitha Fussle; Jorgen Tranum-Jensen



Piezooptical properties of crystals of triglycine sulfate doped with L-alpha-alanine  

NASA Astrophysics Data System (ADS)

Temperature anomalies of the piezooptical constants of triglycine sulfate crystals are usually associated with a shift of the Curie point under mechanical stress. At a certain temperature this leads to a change in the effective value of spontaneous polarization, which determines the contribution of the secondary electrooptical effect to the total piezooptical effect. These assumptions have been experimentally verified for crystals of triglycine sulfate doped with L-alpha-alanine. The temperature dependence of the coefficients of the transverse piezooptical effect for these doped crystals is evaluated, and attention is given to relaxation changes of birefringence and light intensity for crystals doped with 30 percent L-alpha-alanine after the removal of pressure.

Mytsyk, B. G.; Romaniuk, N. A.



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. PMID:23990760



DCFPAK: Dose coefficient data file package for Sandia National Laboratory  

SciTech Connect

The FORTRAN-based computer package DCFPAK (Dose Coefficient File Package) has been developed to provide electronic access to the dose coefficient data files summarized in Federal Guidance Reports 11 and 12. DCFPAK also provides access to standard information regarding decay chains and assembles dose coefficients for all dosimetrically significant radioactive progeny of a specified radionuclide. DCFPAK was designed for application on a PC but, with minor modifications, may be implemented on a UNIX workstation.

Eckerman, K.F.; Leggett, R.W.



Numerical calculation of the transport coefficients in thermal plasmas  

E-print Network

-We have performed a new efficient method to calculate numerically the transport coefficients at high temperature. The collision theory was treated to study singularities that occur when evaluating the collision cross section. The transport coefficients (viscosity, diffusion coefficient, thermal and electrical conductivity) depend strongly on nature of the interaction between the particles that form the plasma and that is why it is necessary to determine the interaction potential accurately.

Mahfouf, Ali; Faure, Géraldine



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.



Alpha Com eclipse observing campaign  

NASA Astrophysics Data System (ADS)

Drs. Matthew W. Muterspaugh and Gregory W. Henry (Tennessee State University) have requested AAVSO observers' ssistance in monitoring the possible Algol-like binary star alpha Com before, during, and after the eclipse they have predicted for mid-to-late January 2015. The PIs will be using the Fairborn Observatory automated photometric telescopes on Mt. Hopkins, but they are requesting additional observations not only to supplement theirs but also specifically to have good coverage in the event of bad weather at Mt. Hopkins. Alf Com has a 26-year period and is 4.32V at maximum. The expected amplitude of the eclipse is about 0.8 magnitude and the duration somewhere between 28 and 45 hours. The eclipse is predicted for January 25 ± three days (JD 2457047 ± 3). Muterspaugh at al. first calculated the possibility of a 2015 eclipse in 2010 (AJ). Muterspaugh and Henry recently published an article with updated information (arXiv 2014). V and/or R photometry (other bands welcome) is requested, with a minimal cadence of one measurement/2 hours, to make sure the eclipse is caught right as it begins and to ensure having multiple data points on any unseen objects that might eclipse as well. During eclipse, continuous observations are important. Infrared (H-band) observations could be interesting, should the CHARA array image the event. The precision photometry in the weeks before and after the eclipse is requested in order to catch possible evidence for planets or other materials around the eclipsing star. Updated astrometry from the current epoch would greatly improve the eclipse preductions. Charts with comparison star sequence for alf Com may be created using the AAVSO Variable Star Plotter ( The PIs recommend using the comparison stars HD 113848 (39 Com, HR 4946, HIP 63948, V=5.990, B-V=0.39, F4V) and HD 114520 (HIP 64312, V=6.820, B-V=0.46,F2II). Observations should be submitted to the AAVSO International Database. See AAVSO Alert Notice 506 for full details.

Waagen, Elizabeth O.



MCNPX alpha particle dose estimate to the skin tissue from a low-enriched uranium fuel fragment.  


Three alpha volume sources (low-enriched uranium-U(3)Si) were analysed using Monte Carlo modelling in order to calculate the dose delivered to the dermis from a small embedded fuel fragment (sliver). Three shapes were analysed using MCNPX 2.6.0 code: sphere, cylinder and parallelepiped. Essentially, two kinds of runs were performed: count rate run and dosimetry run. The two results were combined to estimate dose coefficients that can be used for alpha dose assessments in the field. The two results were obtained for the 1 and 0 cm counting geometries. These results are very stable and show that the actual dose delivered to the skin per unit count rate for the recovered particle is independent of the shape of the volume alpha source. PMID:22003183

Atanackovic, J



The Low-Temperature Seebeck Coefficient in Insulators  

NASA Astrophysics Data System (ADS)

We show the existence of a space-charge effect in the measurement of the low-temperature Seebeck coefficient in insulators. The Seebeck coefficient is obtained by measurement of the voltage due to a temperature gradient . The space-charge effect makes the voltage go to zero in insulators, even if the Seebeck coefficient does not vanish. We propose that the Seebeck coefficient does not actually vanish in insulators, contrary to common belief. We also propose that variable-range hopping is not observed in conductivity measurements.

Mahan, G. D.



Coefficients of convergent multiple Walsh-Paley series  

SciTech Connect

The paper is concerned with the behaviour of the coefficients of multiple Walsh-Paley series that are cube convergent to a finite sum. It is shown that even an everywhere convergent series of this kind may contain coefficients with numbers from a sufficiently large set that grow faster than any preassigned sequence. By Cohen's theorem, this sort of thing cannot happen for multiple trigonometric series that are cube convergent on a set of full measure - their coefficients cannot grow even exponentially. Null subsequences of coefficients are determined for multiple Walsh-Paley series that are cube convergent on a set of definite measure. Bibliography: 18 titles.

Plotnikov, Mikhail G [Vologda State Academy of Milk Industry, Molochnoe, Vologda Region (Russian Federation)



Kinetic theory of the interdiffusion coefficient in dense plasmas  

SciTech Connect

Naive applications of Spitzer's theory to very dense plasmas can lead to negative diffusion coefficients. The interdiffusion coefficients in Binary Ionic Mixtures (two species of point ions in a uniform neutralizing background) have been calculated recently using molecular dynamics techniques. These calculations can provide useful benchmarks for theoretical evaluations of the diffusion coefficient in dense plasma mixtures. This paper gives a brief description of a kinetic theoretic approximation to the diffusion coefficient which generalizes Spitzer to high density and is in excellent agreement with the computer simulations. 15 refs., 1 fig., 2 tabs.

Boercker, D.B.



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)



Effect of kinetic boundary condition on the thermal transpiration coefficient  

NASA Astrophysics Data System (ADS)

The effect of kinetic boundary condition on the free molecular thermal transpiration coefficient ? is analyzed numerically. The Maxwell model boundary condition is applied in its original form in the sense that its accommodation coefficient depends on the speed of incident molecules. The results show that the value of ? depends much on the velocity dependency of the accommodation coefficient. The experimental result, ? < 0.5, can be reproduced if the grazing molecules reflect diffusely. This makes a sharp contrast with the previous works that ? =0.5 for the velocity independent accommodation coefficient.

Sugimoto, Hiroshi; Amakawa, Kenjiro



Acousto-optic interaction in alpha-BaB(2)O(4)and Li(2)B(4)O(7) crystals.  


Experimental studies and analysis of acousto-optic diffraction in alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are given. Ultrasonic wave velocity, elastic compliance and stiffness coefficients, and piezo-optic and photoelastic coefficients of alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are determined. The acousto-optic figure of merit has been estimated for different possible geometries of acousto-optic interaction. It is shown that the acousto-optic figures of merit for alpha-BaB(2)O(4) crystals reach the value M(2)=(270 +/- 70) x 10(-15) s(3)/kg for the case of interaction with the slowest ultrasonic wave. The directions of propagation and polarization of those acoustic waves are obtained on the basis of construction of acoustic slowness surfaces. The acousto-optic diffraction is experimentally studied for alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals. PMID:18594591

Martynyuk-Lototska, Irina; Mys, Oksana; Dudok, Taras; Adamiv, Volodymyr; Smirnov, Yevgen; Vlokh, Rostyslav



Osmotic fragility test in heterozygotes for alpha and beta thalassaemia.  

PubMed Central

This study shows that the combination of heterozygous beta thalassaemia and deletion heterozygous (-alpha/alpha alpha) or homozygous (-alpha/-alpha) alpha+ thalassaemia may result in the production of erythrocytes which have normal mean volume and haemoglobinisation but decreased osmotic fragility. Based on this finding and previous studies, which have shown that beta thalassaemia screening by the osmotic fragility test may miss a significant proportion of beta thalassaemia heterozygotes, we conclude that beta thalassaemia screening in a population in which both alpha and beta thalassaemia are prevalent should combine the one tube osmotic fragility test with electronic measurement of red blood cell indices in the initial screening process. PMID:4078866

Maccioni, L; Cao, A



Stereoselective sorption by agricultural soils and liquid-liquid partitioning of trenbolone (17alpha and 17beta) and trendione.  


Trenbolone acetate (TBA) is a synthetic anabolic hormone used for growth promotion in beef cattle, which excrete primarily 17alpha-trenbolone along with small amounts of 17beta-trenbolone and trendione. To aid in predicting transport of manure-borne TBA metabolites, multiconcentration sorption isotherms for 17alpha- and 17beta-trenbolone and trendione were generated with five autoclaved-sterilized soils that represented a range in soil properties. Hormone concentrations were measured independently in solution and soil phases, and quantified using liquid chromatography with electrospray mass spectrometry. In addition, partition coefficients between apolar hexane and water (K(hw)) and bipolar octanol and water (K(ow)) were measured for the three androgens to better ascertain the mechanisms that may be responsible for the sorption differences observed between isomers. In all five soils, trendione sorbed the most, and 17alpha- and 17beta-trenbolone isomers exhibited different sorption magnitudes. 17beta- trenbolone consistently sorbed a factor of 2 more than 17alpha-trenbolone. For all three androgens, sorption is proportional to the soil organic carbon (OC) content with average log OC-normalized distribution coefficients (log K(oc), L/kg OC) of 2.77 +/- 0.12 for 17alpha-trenbolone, 3.08 +/- 0.1 for 17beta-trenbolone and 3.38 +/- 0.19 for trendione, which suggests the dominance of hydrophobic partitioning. However, differences in K(hw) values between 17alpha- and 17beta-trenbolone were small indicating differences are not simply due to differences in aqueous activity. In contrast, similarly different K(ow) and K(oc) values for the two isomers indicate the likely contribution of H-bonding to stereoselective sorption. PMID:19943653

Khan, Bushra; Qiao, Xianliang; Lee, Linda S



Cancer radioimmunotherapy with alpha-emitting nuclides.  


In lymphoid malignancies and in certain solid cancers such as medullary thyroid carcinoma, somewhat mixed success has been achieved when applying radioimmunotherapy (RIT) with beta-emitters for the treatment of refractory cases. The development of novel RIT with alpha-emitters has created new opportunities and theoretical advantages due to the high linear energy transfer (LET) and the short path length in biological tissue of alpha-particles. These physical properties offer the prospect of achieving selective tumoural cell killing. Thus, RIT with alpha-emitters appears particularly suited for the elimination of circulating single cells or cell clusters or for the treatment of micrometastases at an early stage. However, to avoid non-specific irradiation of healthy tissues, it is necessary to identify accessible tumoural targets easily and rapidly. For this purpose, a small number of alpha-emitters have been investigated, among which only a few have been used for in vivo preclinical studies. Another problem is the availability and cost of these radionuclides; for instance, the low cost and the development of a reliable actinium-225/bismuth-213 generator were probably determining elements in the choice of bismuth-213 in the only human trial of RIT with an alpha-emitter. This article reviews the literature concerning monoclonal antibodies radiolabelled with alpha-emitters that have been developed for possible RIT in cancer patients. The principal radio-immunoconjugates are considered, starting with physical and chemical properties of alpha-emitters, their mode of production, the possibilities and difficulties of labelling, in vitro studies and finally, when available, in vivo preclinical and clinical studies. PMID:15841373

Couturier, Olivier; Supiot, Stéphane; Degraef-Mougin, Marie; Faivre-Chauvet, Alain; Carlier, Thomas; Chatal, Jean-François; Davodeau, François; Cherel, Michel



Identification of sequence segments forming the alpha-bungarotoxin binding sites on two nicotinic acetylcholine receptor alpha subunits from the avian brain.  


The relationship between neuronal alpha-bungarotoxin binding proteins (alpha BGTBPs) and nicotinic acetylcholine receptor function in the brain of higher vertebrates has remained controversial for over a decade. Recently, the cDNAs for two homologous putative ligand binding subunits, designated alpha BGTBP alpha 1 and alpha BGTBP alpha 2, have been isolated on the basis of their homology to the N terminus of an alpha BGTBP purified from chick brain. In the present study, a panel of overlapping synthetic peptides corresponding to the complete chick brain alpha BGTBP alpha 1 subunit and residues 166-215 of the alpha BGTBP alpha 2 subunits were tested for their ability to bind 125I-alpha BGT. The sequence segments corresponding to alpha BGTBP alpha 1-(181-200) and alpha BGTBP alpha 2-(181-200) were found to consistently and specifically bind 125I-alpha BGT. The ability of these peptides to bind alpha BGT was significantly decreased by reduction and alkylation of the Cys residues at positions 190/191, whereas oxidation had little effect on alpha BGT binding activity. The relative affinities for alpha BGT of the peptide sequences alpha BGTBP alpha 1-(181-200) and alpha BGTBP alpha 2-(181-200) were compared with those of peptides corresponding to the sequence segments Torpedo alpha 1-(181-200) and chick muscle alpha 1-(179-198). In competition assays, the IC50 for alpha BGTBP alpha 1-(181-200) was 20-fold higher than that obtained for the other peptides (approximately 2 versus 40 microM). These results indicate that alpha BGTBP alpha 1 and alpha BGTBP alpha 2 are ligand binding subunits able to bind alpha BGT at sites homologous with nAChR alpha subunits and that these subunits may confer differential ligand binding properties on the two alpha BGTBP subtypes of which they are components. PMID:1869552

McLane, K E; Wu, X D; Schoepfer, R; Lindstrom, J M; Conti-Tronconi, B M



Identification of a novel bile acid in swans, tree ducks, and geese: 3alpha,7alpha,15alpha-trihydroxy-5beta-cholan-24-oic acid.  


By HPLC, a taurine-conjugated bile acid with a retention time different from that of taurocholate was found to be present in the bile of the black-necked swan, Cygnus melanocoryphus. The bile acid was isolated and its structure, established by (1)H and (13)C NMR and mass spectrometry, was that of the taurine N-acyl amidate of 3alpha,7alpha,15alpha-trihydroxy-5beta-cholan-24-oic acid. The compound was shown to have chromatographic and spectroscopic properties that were identical to those of the taurine conjugate of authentic 3alpha,7alpha,15alpha-trihydroxy-5beta-cholan-24-oic acid, previously synthesized by us from ursodeoxycholic acid. By HPLC, the taurine conjugate of 3alpha,7alpha,15alpha-trihydroxy-5beta-cholan-24-oic acid was found to be present in 6 of 6 species in the subfamily Dendrocygninae (tree ducks) and in 10 of 13 species in the subfamily Anserinae (swans and geese) but not in other subfamilies in the Anatidae family. It was also not present in species from the other two families of the order Anseriformes. 3alpha,7alpha,15alpha-Trihydroxy-5beta-cholan-24-oic acid is a new primary bile acid that is present in the biliary bile acids of swans, tree ducks, and geese and may be termed 15alpha-hydroxy-chenodeoxycholic acid. PMID:16648547

Kakiyama, Genta; Iida, Takashi; Goto, Takaaki; Mano, Nariyasu; Goto, Junichi; Nambara, Toshio; Hagey, Lee R; Schteingart, Claudio D; Hofmann, Alan F



Subduction coefficients of Birman-Wenzl algebras and Racah coefficients of the quantum groups Oq(n) and Spq(2m): II. Racah coefficients  

NASA Astrophysics Data System (ADS)

Racah coefficients of Oq(n) and Spq(2m) are derived from subduction coefficients of Birman-Wenzl algebras Cf (r,q) by using the Schur-Weyl-Brauer duality relation between Birman-Wenzl algebras Cf (r,q) with r = qn-1 or q-2m-1 and the quantum group Oq(n) or Spq(2m). It is shown that there are two types of the Racah coefficients according to irreps of Oq(n) or Spq(2m) with or without q-deformed trace contraction. The Racah coefficients without q-deformed trace contraction in the irreps involved are n-independent, and are the same as those of quantum groups Uq(n). As examples, Racah coefficients of Oq(n) with q-deformed trace contraction for the resulting irreps MATHS-n1n2dot0 with n1 + n2 ? 2 are tabulated, which are also Racah coefficients of Spq(2m) with substitution n?-2m and conjugation of the corresponding irreps.

Dai, Lianrong; Pan, Feng; Draayer, J. P.



Alpha Channeling in Rotating Plasma with Stationary Waves  

SciTech Connect

An extension of the alpha channeling effect to supersonically rotating mirrors shows that the rotation itself can be driven using alpha particle energy. Alpha channeling uses radiofrequency waves to remove alpha particles collisionlessly at low energy. We show that stationary magnetic fields with high n? can be used for this purpose, and simulations show that a large fraction of the alpha energy can be converted to rotation energy.

A. Fetterman and N.J. Fisch



EEG alpha power and alpha power asymmetry in sleep and wakefulness  

E-print Network

sleep, particularly during rapid eye movement ~REM! sleep. These results suggest that patterns during dreaming. During sleep, alpha power was highest during slow-wave sleep and lowest during REM sleep and sleeping are considered. Descriptors: Electroencephalography, Alpha, Sleep, REM sleep, Human Individual

Wisconsin at Madison, University of


Experimental and Theoretical Electron Density Distribution of Alpha,Alpha-Trehalose Dihydrate  

Technology Transfer Automated Retrieval System (TEKTRAN)

Alpha,alpha-rehalose is of interest because of its cryoprotective and antidessicant properties, and because it possesses various technical anomalies such as 13C NMR spectra that give misleading indications of intramolecular structural symmetry. It is a non-reducing disaccharide, with the glycosidic...


Effects of $\\alpha$-cluster breaking on 3$\\alpha$ cluster structures in $^{12}$C  

E-print Network

To clarify the effects of $\\alpha$-cluster breaking on 3$\\alpha$ cluster structures in $^{12}$C, we investigate $^{12}$C using a hybrid model that combines the Brink-Bloch cluster model with the $p_{3/2}$ subshell closure wave function. We have found that $\\alpha$-cluster breaking caused by spin-orbit force significantly changes cluster structures of excited $0^{+}$ states through orthogonality to lower states. Spatially developed cluster components of the $0^{+}_{2}$ state are reduced. The $0^{+}_{3}$ state changes from a vibration mode in the bending motion of three $\\alpha$ clusters to a chain-like 3$\\alpha$ structure having an open triangle configuration. As a result of these structure changes of $0^{+}$ states, the band assignment for the $2^{+}_{2}$ state is changed by the $\\alpha$-cluster breaking effect. Namely, in model calculations without the $\\alpha$-cluster breaking effect, the $0^{+}_{2}$ state is assigned to be the band-head of the $2^{+}_{2}$ state. However, when we incorporate $\\alpha$-cluste...

Suhara, Tadahiro



Amyloid formation and disaggregation of {alpha}-synuclein and its tandem repeat ({alpha}-TR)  

SciTech Connect

Research highlights: {yields} Formation of the {alpha}-synuclein amyloid fibrils by [BIMbF{sub 3}Im]. {yields} Disaggregation of amyloid fibrils by epigallocatechin gallate (EGCG) and baicalein. {yields} Amyloid formation of {alpha}-synuclein tandem repeat ({alpha}-TR). -- Abstract: The aggregation of {alpha}-synuclein is clearly related to the pathogenesis of Parkinson's disease. Therefore, detailed understanding of the mechanism of fibril formation is highly valuable for the development of clinical treatment and also of the diagnostic tools. Here, we have investigated the interaction of {alpha}-synuclein with ionic liquids by using several biochemical techniques including Thioflavin T assays and transmission electron microscopy (TEM). Our data shows a rapid formation of {alpha}-synuclein amyloid fibrils was stimulated by 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BIMbF{sub 3}Im], and these fibrils could be disaggregated by polyphenols such as epigallocatechin gallate (EGCG) and baicalein. Furthermore, the effect of [BIMbF{sub 3}Im] on the {alpha}-synuclein tandem repeat ({alpha}-TR) in the aggregation process was studied.

Bae, Song Yi; Kim, Seulgi; Hwang, Heejin; Kim, Hyun-Kyung; Yoon, Hyun C.; Kim, Jae Ho [Department of Molecular Science and Technology, Graduate School of Interdisciplinary Programs, Ajou University, Suwon 443-749 (Korea, Republic of)] [Department of Molecular Science and Technology, Graduate School of Interdisciplinary Programs, Ajou University, Suwon 443-749 (Korea, Republic of); Lee, SangYoon, E-mail: [Chronic Inflammatory Disease Research Center, School of Medicine, Ajou University, Suwon 443-749 (Korea, Republic of)] [Chronic Inflammatory Disease Research Center, School of Medicine, Ajou University, Suwon 443-749 (Korea, Republic of); Kim, T. Doohun, E-mail: [Department of Molecular Science and Technology, Graduate School of Interdisciplinary Programs, Ajou University, Suwon 443-749 (Korea, Republic of)



Structure and anti-acetylcholinesterase activity of 4 alpha-(hydroxymethyl)-4 alpha-demethylterritrem B.  


The structure of a metabolite produced on incubation of territrem B (1) with rat liver microsomes has been established to be 4 alpha-(hydroxymethyl)-4 alpha-demethylterritrem B (5). Compound 5 was a potent inhibitor of electric eel acetylcholinesterase (AChE) (E.C. PMID:9287420

Peng, F C



Oxygen diffusion in alpha-Al2O3. Ph.D. Thesis  

NASA Technical Reports Server (NTRS)

Oxygen self diffusion coefficients were determined in single crystal alpha-Al2O3 using the gas exchange technique. The samples were semi-infinite slabs cut from five different boules with varying background impurities. The diffusion direction was parallel to the c-axis. The tracer profiles were determined by two techniques, single spectrum proton activation and secondary ion mass spectrometry. The SIMS proved to be a more useful tool. The determined diffusion coefficients, which were insensitive to impurity levels and oxygen partial pressure, could be described by D = .00151 exp (-572kJ/RT) sq m/s. The insensitivities are discussed in terms of point defect clustering. Two independent models are consistent with the findings, the first considers the clusters as immobile point defect traps which buffer changes in the defect chemistry. The second considers clusters to be mobile and oxygen diffusion to be intrinsic behavior, the mechanism for oxygen transport involving neutral clusters of Schottky quintuplets.

Cawley, J. D.; Halloran, J. W.; Cooper, A. R.




NASA Technical Reports Server (NTRS)

The two principal functions of PAC91 are to provide a means of generating theoretical thermodynamic functions from molecular constant data and to supply a means of fitting these functions to empirical equations by using a least-squares fit. The coefficients obtained from the fit may then be used to generate a library of thermodynamic data in a uniform and easy-to-use format for use in other computer codes. Several large compilations of selected or calculated thermodynamic data currently exist. Nevertheless, there is a continuing need for additional calculations due to the discovery of new species, the revision of existing molecular constant data and structural parameters, the need for data at temperatures other than those already published, the availability of new or revised heats of formation, dissociation or transition, and the revision of fundamental constants or atomic weights. Calculations may also be needed to compare the results of assuming various possible forms of the partition function. In addition, there is often a preference for thermodynamic data in functional rather than tabular form. In order to satisfy these needs, the PAC91 program can perform any combination of the following: (1) calculate thermodynamic functions (heat capacity, enthalpy, entropy, and Gibbs energy) for any set of 1 to 202 temperatures, (2) obtain a least-squares fit of the first three of these functions (either individually, two at a time, or all three simultaneously) for up to eight temperature intervals, and (3) calculate, as a function of temperature, heats of formation and equilibrium constants from assigned reference elements. The thermodynamic functions for ideal gases may be calculated from molecular constant data using one of several partition function variations provided by the program. For monatomic gases, one of three partition function cutoff techniques may be selected by the user, and unobserved but predicted electronic energy levels may be included by the program. For diatomic and polyatomic gases, one of five partition functions are available. These differ in the correction factors for nonrigid rotation, anharmonicity, and vibration-rotation interactions. Excited electronic states may also be included. Several other capabilities of the program include the estimation of thermodynamic properties by a group additivity method, the ability to calculate properties for species with internal rotors, and a method for extrapolating data to high temperatures. For the purpose of additional processing, known thermodynamic functions for solids, liquids, or gases may be read in directly or thermodynamic functions may be calculated from heat capacity equations. PAC91 is written in FORTRAN 77 to be machine independent. It requires 1Mb of RAM for execution. It has been tested on a Sun SLC running SunOS, a DECstation 3100 running ULTRIX, an IBM RS/6000 running AIX, and a MicroVAX 3600 running VMS. It has not been implemented under DOS. The standard distribution medium for PAC91 is a .25 inch streaming magnetic tape cartridge (Sun QIC-24 format) in UNIX tar format. Other distribution media and formats are available upon request. The program PAC1 was originally released in 1967, and has been continuously revised, updated, and extended. PAC91, the latest version, was released in 1993.

Mcbride, B. J.



Oligoclonal repertoire of the CD8 alpha alpha and the CD8 alpha beta TCR-alpha/beta murine intestinal intraepithelial T lymphocytes: evidence for the random emergence of T cells  

PubMed Central

The epithelium of the small intestine in normal euthymic mice contains a large number of intraepithelial lymphocytes (IEL), some of which bear a T cell receptor alpha/beta (TCR-alpha/beta). About half of these TCR- alpha/beta IEL display the CD8 alpha alpha phenotype and the remaining have the CD8 alpha beta or the CD4 phenotypes. To examine whether TCR- alpha/beta IEL have a TCR-beta chain repertoire as diverse as that of TCR-alpha/beta lymph node lymphocytes (LNL), we used a recently described PCR technique that allows a global analysis of the TCR-beta chain repertoire. Within any given mouse, the repertoires expressed in both CD8 alpha alpha and CD8 alpha beta TCR-alpha/beta IEL populations are oligoclonal and nonoverlapping between the two subsets. The clones are largely conserved through the length of the small intestine of the same individual. However, genetically identical individuals raised under indistinguishable environmental conditions display distinct oligoclonal repertoires. Those findings indicate that few cells of CD8 alpha alpha or of the CD8 alpha beta phenotype are responsible for the repopulation of the intestinal epithelium. PMID:7931068



Alpha satellite DNA in neotropical primates (Platyrrhini).  


The alpha satellite DNA of Old World (catarrhine) primates usually consists of similar, but not identical, ca. 170 bp sequences repeated tandemly hundreds to thousands of times. The 170 bp monomeric repeats are components of higher-order repeats, many of which are chromosome specific. Alpha satellites are found exclusively in centromeric regions where they appear to play a role in centromere function. We have found that alpha satellite DNA in neotropical (New World; platyrrhine) primates is very similar to its Old World counterpart: it consists of divergent ca. 170 bp subsequences that are arranged in tandem arrays with a ca. 340 bp periodicity. New and Old World alpha satellites share about 64% sequence identity overall, and contain several short sequence motifs that appear to be highly conserved. One exception to the tandemly arrayed 340 bp motif has been found: the major alpha satellite array in Chiropotes satanas (black bearded saki) has a 539 bp repeat unit that consists of a 338 bp dimer together with a duplication of 33 bp of the first monomeric unit and 168 bp of the second monomeric unit. PMID:7988287

Alves, G; Seuánez, H N; Fanning, T



Alpha-particle sensitive test SRAMs  

NASA Technical Reports Server (NTRS)

A bench-level test is being developed to evaluate memory-cell upsets in a test SRAM designed with a cell offset voltage. This offset voltage controls the critical charge needed to upset the cell. The effect is demonstrated using a specially designed 2-micron n-well CMOS 4-kb test SRAM and a Po-208 5.1-MeV 0.61-LET alpha-particle source. This test SRAM has been made sensitive to alpha particles through the use of a cell offset voltage, and this has allowed a bench-level characterization in a laboratory setting. The experimental data are linked to a alpha-particle interaction physics and to SPICE circuit simulations through the alpha-particle collection depth. The collection depth is determined by two methods and found to be about 7 micron. In addition, alpha particles that struck outside the bloated drain were able to flip the SRAM cells. This lateral charge collection was observed to be more than 6 micron.

Buehler, M. G.; Blaes, B. R.



Measurement of the Strong Coupling Constant Alpha  

NASA Astrophysics Data System (ADS)

The strong coupling constant alpha _{rm s} has been measured from the rate of jet production observed in W events collected by the UA1 detector from proton-antiproton collisions at sqrt{rm s} = 630 GeV at the CERN collider. W bosons are to a first approximation produced by quark-antiquark annihilation at the CERN pp collider. Strong interactions led to hadronic jets emitted with the W. To first order the rate of jet production is proportional to the strong coupling constant. Experimental and theoretical difficulties make the determination of alpha_{rm s} more complicated. The ratio of the number of W events observed with one jet to the number of W events with no jet was measured. This result was then compared to a QCD predicted ratio which was a function of the strong coupling constant. The QCD predicted ratio was calculated using the EKS and ISAJET Monte Carlos in conjunction with a full simulation of the UA1 detector. The value of alpha_{rm s} was varied until the experimental and predicted ratios were equal. The value of alpha_{rm s} was found to be alpha_{ rm s} =.127 +/-.026(stat.) +/-.022(exp. syst.) +/- .025(theor. syst.).

Lindgren, Michael Allen



alpha-nucleus potentials, alpha-decay half-lives, and shell closures for superheavy nuclei  

E-print Network

Systematic alpha-nucleus folding potentials are used to analyze alpha-decay half-lives of superheavy nuclei. Preformation factors of about several per cent are found for all nuclei under study. The systematic behavior of the preformation factors and the volume integrals of the potentials allows to predict alpha-decay energies and half-lives for unknown nuclei. Shell closures can be determined from measured alpha-decay energies using the discontinuity of the volume integral at shell closures. For the first time a double shell closure is predicted for Z_magic = 132, N_magic = 194, and A_magic = 326 from the systematics of folding potentials. The calculated alpha-decay half-lives remain far below one nanosecond for superheavy nuclei with double shell closure and masses above A > 300 independent of the precise knowledge of the magic proton and neutron numbers.

Peter Mohr



Rat plasma alpha 1-inhibitor3: a member of the alpha-macroglobulin family.  


The overall mechanism of interaction with proteinases of alpha 1-inhibitor3, a plasma proteinase inhibitor so far specific to the rat, has been shown to be closely similar to that described for alpha-macroglobulins. This mechanism includes: (i) the cleavage of at least one susceptible peptidic bond which leads to structural changes in the molecule. (ii) The cleavage of a putative thiol ester bond in another site of the molecule which permits the covalent linkage of the enzyme. Moreover, fragmentation of alpha 1-inhibitor3 upon heating as observed for alpha-macroglobulin quarter subunits has been demonstrated. The question is raised of the presence of such a molecule in rat plasma in addition to two alpha-macroglobulin species, all of these proteinase inhibitors being antigenically unrelated. PMID:2578988

Esnard, F; Gutman, N; el Moujahed, A; Gauthier, F



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



Measurement of Seebeck coefficient perpendicular to SiGe superlattice  

Microsoft Academic Search

Seebeck coefficient is one of the key parameters to evaluate the performance of thermoelectric coolers. However, it is very difficult to directly measure Seebeck coefficient perpendicular to thin film devices because of the difficulty of creating a temperature gradient and measuring localized temperature and voltage change simultaneously. In this paper, a novel method is described and it is used to

Yan Zhang; Gehang Zeng; Rajeev Singh; James Christofferson; Edward Croke; John E. Bowers; Ali Shakouri



Texture Characterization via Joint Statistics of Wavelet Coefficient Magnitudes  

Microsoft Academic Search

We present a parametric statistical characterization of texture images in the context of an overcomplete complex wavelet frame. The characterization consists of the local autocorrelation of the coefficients in each subband, the lo- cal autocorrelation of the cofficent magnitudes, and the cross- correlation of coefficient magnitudes at all orientations and adjacent spatial scales. We develop an efficient algorithm for sampling

Eero P. Simoncelli; Javier Portilla



A Simple Geometric Approach to Approximating the Gini Coefficient  

ERIC Educational Resources Information Center

The author shows how a quick approximation of the Lorenz curve's Gini coefficient can be calculated empirically using numerical data presented in cumulative income quintiles. When the technique here was used to estimate 621 income quintile/Gini coefficient observations from the Deninger and Squire/World Bank data set, this approach performed…

Kasper, Hirschel; Golden, John



Micro- and macroscale coefficients of friction of cementitious materials  

SciTech Connect

Millions of metric tons of cementitious materials are produced, transported and used in construction each year. The ease or difficulty of handling cementitious materials is greatly influenced by the material friction properties. In the present study, the coefficients of friction of cementitious materials were measured at the microscale and macroscale. The materials tested were commercially-available Portland cement, Class C fly ash, and ground granulated blast furnace slag. At the microscale, the coefficient of friction was determined from the interaction forces between cementitious particles using an Atomic Force Microscope. At the macroscale, the coefficient of friction was determined from stresses on bulk cementitious materials under direct shear. The study indicated that the microscale coefficient of friction ranged from 0.020 to 0.059, and the macroscale coefficient of friction ranged from 0.56 to 0.75. The fly ash studied had the highest microscale coefficient of friction and the lowest macroscale coefficient of friction. -- Highlights: •Microscale (interparticle) coefficient of friction (COF) was determined with AFM. •Macroscale (bulk) COF was measured under direct shear. •Fly ash had the highest microscale COF and the lowest macroscale COF. •Portland cement against GGBFS had the lowest microscale COF. •Portland cement against Portland cement had the highest macroscale COF.

Lomboy, Gilson [Department of Civil, Construction, and Environmental Engineering, Iowa State University, Ames, IA 50011 (United States)] [Department of Civil, Construction, and Environmental Engineering, Iowa State University, Ames, IA 50011 (United States); Sundararajan, Sriram, E-mail: [Department of Mechanical Engineering, Iowa State University, Ames, IA 50011 (United States)] [Department of Mechanical Engineering, Iowa State University, Ames, IA 50011 (United States); Wang, Kejin [Department of Civil, Construction, and Environmental Engineering, Iowa State University, Ames, IA 50011 (United States)] [Department of Civil, Construction, and Environmental Engineering, Iowa State University, Ames, IA 50011 (United States)



Object detection by correlation coefficients using azimuthally averaged reference projections  

Microsoft Academic Search

A method of computing correlation coefficients for object detection that takes advantage of using azimuthally averaged reference projections is described and compared with two alternative methods-computing a cross-correlation function or a local correlation coefficient versus the azimuthally averaged reference projections. Two examples of an application from structural biology involving the detection of projection views of biological macromolecules in electron micrographs

William V. Nicholson



A program to compute aquifer-response coefficients  

USGS Publications Warehouse

An alternating direction technique is used to solve finite difference equations approximating the flow of water in an aquifer. The solutions produce response coefficients relating pumping from wells to drawdowns within those wells. The product of the response coefficient with the pumping values produces a linear algebraic technological function that can be used for integrating hydrologic phenomena into planning and management models.

Maddock, Thomas



REE and Strontium Partition Coefficients for Nakhla Pyroxenes  

NASA Technical Reports Server (NTRS)

We present new partition coefficients for REE and Sr determined using a synthetic melt that crystallizes pyroxenes very similar in composition to Nakhla pyroxene cores. We believe these are the most appropriate partition coefficients to use in studying Nakhla Additional information is contained in the original extended abstract..

Oe, K.; McKay, G.; Le, L.



Extracting electron backscattering coefficients from backscattered electron micrographs  

SciTech Connect

Electron backscattering micrographs possess the so-called Z-contrast, carrying information about the chemical compositions of phases present in microstructures. The intensity at a particular point in the backscattered electron micrograph is proportional to the signal detected at a corresponding point in the scan raster, which is, in turn, proportional to the electron backscattering coefficient of a phase at that point. This article introduces a simple method for extracting the electron backscattering coefficients of phases present in the microstructure, from the backscattered electron micrographs. This method is able to convert the micrograph's greyscale to the backscattering-coefficient-scale. The prerequisite involves the known backscattering coefficients for two phases in the micrograph. In this way, backscattering coefficients of other phases can be determined. The method is unable to determine the chemical compositions of phases or the presence of an element only from analysing the backscattered electron micrograph. Nevertheless, this method was found to be very powerful when combined with energy dispersive spectroscopy, and the calculations of backscattering coefficients. - Research Highlights: {yields}A simple method for extracting the electron backscattering coefficients {yields}The prerequisite is known backscattering coefficients for two phases {yields}The information is complementary to the EDS-results. {yields}This method is especially useful when a phase contains a light element (H, Li, Be, and B)

Zupanic, F., E-mail:




E-print Network

) with discontinuous diffusion coefficients occur in application domains such as diffusions through porous media, electro-magnetic field propagation on heterogeneous media, and diffusion processes on rough surfaces theory for elliptic PDEs assumes bounds for the distortion of the coefficients in the L norm

Bonito, Andrea


Piezoelectric coefficients of l-alanine doped TGS crystals  

Microsoft Academic Search

Double beam laser interferometry has been used to study small displacement of LATGS crystals caused by the converse piezoelectric effect. All eight nonzero mutually independent piezoelectric coefficients di? have been derived. The temperature dependence of the piezoelectric coefficient d22 has been measured using the single beam Michelson interferometer. The phase transition temperature was determined near 324K.

Dagmar Barosova; Stanislav Panos




E-print Network

--ANDREAS LIE Abstract. A new front tracking method is developed for the variable coefficient equation u t + V lines, the discontinuities travel along paths satisfying an ordinary differential equation. By carefully coefficient case. We show that the new method is well­defined under some mild restrictions on the velocity V


Non-additive quantum corrections to the virial coefficients  

NASA Astrophysics Data System (ADS)

Non-additive contribution to the first quantum correction to the fourth virial coefficient is derived; the result is exact at the level of graphs with at most two triplet potentials. Values of non-additive quantum corrections to the third and fourth virial coefficients are given for a Lennard-Jones and realistic pair-potential functions.

Monago, K. O.



Feedback reactivity coefficients for the Syrian MNSR research reactor  

Microsoft Academic Search

The feedback reactivity coefficients which account for variation in fuel and moderator temperatures as well as the void coefficient have been calculated using the WIMS-D\\/4 and CITATION codes for the Syrian MNSR research reactor. The cross sections of all the reactor components at different temperatures were generated using the WIMSD4 code. These group constants were used then in the CITATION

H. Omar; K. Khattab; N. Ghazi


On the coefficients of differentiated expansions of ultraspherical polynomials  

NASA Technical Reports Server (NTRS)

A formula expressing the coefficients of an expression of ultraspherical polynomials which has been differentiated an arbitrary number of times in terms of the coefficients of the original expansion is proved. The particular examples of Chebyshev and Legendre polynomials are considered.

Karageorghis, Andreas; Phillips, Timothy N.




EPA Science Inventory

A literature search was performed for dissolved organic carbon/water partition coefficients for nonionic chemicals (Kdoc) and Kdoc data was taken from more than sixty references. The Kdoc data were evaluated as a function of the n-octanol/water partition coefficients (Kow). A pre...


Light scattering coefficient by quartz particles suspended in seawater  

Microsoft Academic Search

A fast algorithm to compute scattering coefficient of quartz particles is presented. The algorithm is based on a regression between scattering efficiency and size parameter. This regression relationship was obtained by analyzing results of extensive Mie calculations in the range of size parameters between 48 to 40,000. A FORTRAN subroutine to compute scattering and backscattering coefficients of quartz suspensions is

Vladimir I. Haltrin; Eugeny B. Shybanov; Robert H. Stavn; Alan D. Weidemann



Coefficient Change in Input–Output Models: Theory and Applications  

Microsoft Academic Search

A general theory of coefficient change in input–output and social accounting models is proposed. The major contribution is the introduction of the notion of a ‘field of influence’ as the basis for interpreting the effects of coefficient change. This basis is elaborated through a set of propositions. In Section 3, the implications are explored; first, the first-order changes in one

Michael Sonis; Geoffrey J. D. Hewings



An experimental study on oil-film dynamic coefficients  

Microsoft Academic Search

The oil-film force of hydrodynamic bearing is often characterized by a set of linear stiffness and damping coefficients. This paper presents an experimental method to recognize these coefficients and establishes their characteristics under varieties of operating conditions. The fundamental test model is obtained from a Taylor series expansion of bearing reaction force. A delicate test rig is constructed and experimental

Hua Zhou; Sanxing Zhao; Hua Xu; Jun Zhu



Analysis of asymmetrical cold rolling with varying coefficients of friction  

Microsoft Academic Search

In this research, asymmetrical cold rolling was produced by the difference in the coefficient of friction between rolls and sheets rather than the difference of roll radius or rotation speeds. The influence of friction coefficient ratio on the cross shear deformation, rolling pressure and torque was investigated using slab analysis. The results showed that the shear deformation zone length increased

H Gao; S. C Ramalingam; G. C Barber; G Chen




E-print Network

VISCOSITY SOLUTIONS OF HAMILTON­JACOBI EQUATIONS WITH DISCONTINUOUS COEFFICIENTS GIUSEPPE MARIA of viscosity solution to the Cauchy problem, and that the front tracking algorithm yields an L contractive semigroup. We define a viscosity solution by treating the discontinuities in the coefficients analogously


On univalent function with negative coefficients by using differential operator  

NASA Astrophysics Data System (ADS)

A new differential operator D?,?,?,?m is introduced and a new subclass of analytic functions with negative coefficients defined by this operator is investigated. Some results on coefficient inequalities, distortion theorems and extreme points of analytic functions belonging to the subclass are obtained.

Alamri, Mohammed; Darus, Maslina



APPENDIX E Partition Coefficients For Chromium(VI)  

E-print Network

APPENDIX E Partition Coefficients For Chromium(VI) #12;Appendix E Partition Coefficients For Chromium(VI) E.1.0 Background The review of chromium Kd data obtained for a number of soils (summarized in Table E.1) indicated that a number of factors influence the adsorption behavior of chromium


A Class of Repeated Measures Concordance Correlation Coefficients  

Microsoft Academic Search

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

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



Temperature dependence of the diffusion coefficient of nanoparticles  

NASA Astrophysics Data System (ADS)

The temperature dependence of the diffusion coefficient of nanoparticles in gases has been experimentally studied. It is established that this dependence significantly differs from that predicted by various correlations, in particular, by the Cunningham-Millikan-Davies correlation that is used as an instrumental basis for virtually all methods of measurement of the diffusion coefficient in aerosols.

Rudyak, V. Ya.; Dubtsov, S. N.; Baklanov, A. M.



Diffusion coefficient in hydrogel under high-frequency ultrasound  

Microsoft Academic Search

Modulating hydrogel properties by external stimuli can be applied for drug delivery system. For example, ultrasound can enhance drug release from hydrogel by the mechanism which is not fully understood. We measured diffusion coefficient in hydrogel under high-frequency ultrasound to understand mass transport property. To estimate diffusion coefficient, FRAP (fluorescence recovery after photobleaching) technique was applied with time-lapse fluorescence microscopy

Akira Tsukamoto; Kei Tanaka; Tatsuya Kumata; Yoshiaki Watanabe; Shogo Miyata; Katsuko Furukawa; Takashi Ushida



Factor Scores, Structure and Communality Coefficients: A Primer  

ERIC Educational Resources Information Center

(Purpose) The purpose of this paper is to present an easy-to-understand primer on three important concepts of factor analysis: Factor scores, structure coefficients, and communality coefficients. Given that statistical analyses are a part of a global general linear model (GLM), and utilize weights as an integral part of analyses (Thompson, 2006;…

Odum, Mary



A new correlation coefficient for bivariate time-series data  

NASA Astrophysics Data System (ADS)

The correlation in time series has received considerable attention in the literature. Its use has attained an important role in the social sciences and finance. For example, pair trading in finance is concerned with the correlation between stock prices, returns, etc. In general, Pearson’s correlation coefficient is employed in these areas although it has many underlying assumptions which restrict its use. Here, we introduce a new correlation coefficient which takes into account the lag difference of data points. We investigate the properties of this new correlation coefficient. We demonstrate that it is more appropriate for showing the direction of the covariation of the two variables over time. We also compare the performance of the new correlation coefficient with Pearson’s correlation coefficient and Detrended Cross-Correlation Analysis (DCCA) via simulated examples.

Erdem, Orhan; Ceyhan, Elvan; Varli, Yusuf



Activity coefficients in the surface phase of liquid mixtures.  


A novel equation for evaluating surface activity coefficients is obtained from a recent thermodynamic formalism describing the surface phase of liquid mixtures. The input quantities are the surface tension, bulk activity coefficients and pure constituent thermophysical properties. It is demonstrated thermodynamically that the order of magnitude of each component surface and bulk activity coefficients must be the same. This order is intrinsically associated with the sign of excess surface tension. Reliable activity coefficients of ethanol and water in the surface phase of their mixtures are computed and reported for the first time, by using literature data for the required input quantities. It is shown that the so-called transferring method for estimating surface activity coefficients is severely flawed, because it leads to contradictory values of predicted excess surface tensions depending on which component this prediction is based. PMID:25404471

Santos, M Soledade C S; Reis, João Carlos R



Study on the extinction coefficient of spherical aerosol particles  

NASA Astrophysics Data System (ADS)

Based on Mie scattering theory, this paper introduces the basic principle of aerosol light scattering and the basic calculation method of the polarization characteristics of scattering light. The spherical aerosol model is widely applied for the convenient and simple theoretic calculation, using the scattering theory by introducing the scattering amplitude matrix to combine incident radiation with scattering light. In scattering theory, aerosol extinction parameter has very important role for improving the precision of the laser radar, remote sensing detection and so on. We have mainly discussed the relationship between the spherical particle radius and extinction coefficient, and relationship between refractive index of the particles and extinction coefficient, respectively. It is concluded that extinction coefficient as a function of particles' radius gradually oscillate approaching to 2 with the increasing of particle radius, and extinction coefficient curves as a function of refraction index have completely symmetric. The first major maximum of extinction coefficient also has obvious changes with different particles radius or refractive index.

Yang, Jian; Chen, He; Zhang, Yin-chao; Chen, Si-ying; Guo, Pan; Liu, Li-na



Direct Extraction of One-loop Integral Coefficients  

SciTech Connect

We present a general procedure for obtaining the coefficients of the scalar bubble and triangle integral functions of one-loop amplitudes. Coefficients are extracted by considering two-particle and triple unitarity cuts of the corresponding bubble and triangle integral functions. After choosing a specific parameterization of the cut loop momentum we can uniquely identify the coefficients of the desired integral functions simply by examining the behavior of the cut integrand as the unconstrained parameters of the cut loop momentum approach infinity. In this way we can produce compact forms for scalar integral coefficients. Applications of this method are presented for both QCD and electroweak processes, including an alternative form for the recently computed three-mass triangle coefficient in the six-photon amplitude A{sub 6}(1{sup -}, 2{sup +}, 3{sup -}, 4{sup +}, 5{sup -}, 6{sup +}). The direct nature of this extraction procedure allows for a very straightforward automation of the procedure.

Forde, Darren



Feature Selection for Varying Coefficient Models With Ultrahigh Dimensional Covariates  

PubMed Central

This paper is concerned with feature screening and variable selection for varying coefficient models with ultrahigh dimensional covariates. We propose a new feature screening procedure for these models based on conditional correlation coefficient. We systematically study the theoretical properties of the proposed procedure, and establish their sure screening property and the ranking consistency. To enhance the finite sample performance of the proposed procedure, we further develop an iterative feature screening procedure. Monte Carlo simulation studies were conducted to examine the performance of the proposed procedures. In practice, we advocate a two-stage approach for varying coefficient models. The two stage approach consists of (a) reducing the ultrahigh dimensionality by using the proposed procedure and (b) applying regularization methods for dimension-reduced varying coefficient models to make statistical inferences on the coefficient functions. We illustrate the proposed two-stage approach by a real data example. PMID:24678135

Li, Runze; Wu, Rongling



EOP and low degree geopotential coefficients from SLR data  

NASA Astrophysics Data System (ADS)

The second-degree geopotential coefficients reflect the behaviour of the Earth's inertia tensor of order 2, describing in turn the main mass variations of our planet impacting EOP. SLR data from geodetic satellite constellation span now almost three decades; their reduction with refined data analysis procedures allows to estimate the low degree geopotential coefficients very accurately, in order to detect trends and periodic variations related to tidal effects and atmospheric/oceanic mass variations. In particular, the monthly C20 coefficients determined with SLR data can be correlated with the LOD determinations and the C21/S21 coefficients with the variations of the Earth's principal figure axis, in turn related to the pole motion. Time and frequency analysis of the SLR estimated geopotential coefficients as well as of independently estimated EOP and related excitation functions will be presented.

Luceri, V.; Sciarretta, C.; Bianco, G.



Personal dose equivalent conversion coefficients for neutron fluence over the energy range of 20 to 250 MeV  

SciTech Connect

Monte Carlo simulations were performed to extend existing neutron personal dose equivalent fluence-to-dose conversion coefficients to an energy of 250 MeV. Presently, conversion coefficients, H(p,slab)(10,alpha)/Phi, are given by ICRP-74 and ICRU-57 for a range of angles of radiation incidence (alpha = 0, 15, 30, 45, 60 and 75 degrees ) in the energy range from thermal to 20 MeV. Standard practice has been to base operational dose quantity calculations <20 MeV on the kerma approximation, which assumes that charged particle secondaries are locally deposited, or at least that charged particle equilibrium exists within the tally cell volume. However, with increasing neutron energy the kerma approximation may no longer be valid for some energetic secondaries such as protons. The Los Alamos Monte Carlo radiation transport code MCNPX was used for all absorbed dose calculations. Transport models and collision-based energy deposition tallies were used for neutron energies >20 MeV. Both light and heavy ions (HIs) (carbon, nitrogen and oxygen recoil nuclei) were transported down to a lower energy limit (1 keV for light ions and 5 MeV for HIs). Track energy below the limit was assumed to be locally deposited. For neutron tracks <20 MeV, kerma factors were used to obtain absorbed dose. Results are presented for a discrete set of angles of incidence on an ICRU tissue slab phantom.

Mclean, Thomas D [Los Alamos National Laboratory; Justus, Alan L [Los Alamos National Laboratory; Gadd, S Milan [Los Alamos National Laboratory; Olsher, Richard H [RP-2; Devine, Robert T [RP-2



Microdosimetry for Targeted Alpha Therapy of Cancer  

PubMed Central

Targeted alpha therapy (TAT) has the advantage of delivering therapeutic doses to individual cancer cells while reducing the dose to normal tissues. TAT applications relate to hematologic malignancies and now extend to solid tumors. Results from several clinical trials have shown efficacy with limited toxicity. However, the dosimetry for the labeled alpha particle is challenging because of the heterogeneous antigen expression among cancer cells and the nature of short-range, high-LET alpha radiation. This paper demonstrates that it is inappropriate to investigate the therapeutic efficacy of TAT by macrodosimetry. The objective of this work is to review the microdosimetry of TAT as a function of the cell geometry, source-target configuration, cell sensitivity, and biological factors. A detailed knowledge of each of these parameters is required for accurate microdosimetric calculations. PMID:22988479

Huang, Chen-Yu; Guatelli, Susanna; Oborn, Bradley M.; Allen, Barry J.



Analysis of H-alpha flare spectra  

NASA Technical Reports Server (NTRS)

Spectrographs of the H-alpha line taken at 15 second intervals from the event of 5 Sept. 1973 were interpreted by comparison with synthetic profiles. A sequence of 27 high resolution H alpha profiles was obtained from the second brightest flare kernel. The profiles were generally self reversed with a maximum peak intensity of 1.16 x continuum and a maximum central intensity of .91 x continuum. The line characteristics such as red and violet peak intensities and positions, center shifts and wing intensities were tabulated. Synthetic H-alpha profiles were generated from a finite layer assuming simple parameteric forms for the source function and velocity field. The velocity chosen always decreased with optical depth and had the same sign. For absorption profiles, bisector shifts were calculated for a variety of velocities. The velocity field and source function were derived as a function of optical depth and time.

Kulander, J. L.



Nuclear diagnostic for fast alpha particles  


Measurement of the velocity distribution of confined energetic alpha particles resulting from deuterium-tritium fusion reactions in a magnetically contained plasma is provided. The fusion plasma is seeded with energetic boron neutrals for producing, by means of the reaction .sup.10 B (.alpha.,n) .sup.13 N reaction, radioactive nitrogen nuclei which are then collected by a probe. The radioactivity of the probe is then measured by conventional techniques in determining the energy distribution of the alpha particles in the plasma. In a preferred embodiment, diborane gas (B.sub.2 H.sub.6) is the source of the boron neutrals to produce .sup.13 N which decays almost exclusively by positron emission with a convenient half-life of 10 minutes.

Grisham, Larry R. (Lawrence Township, Mercer County, NJ); Post, Jr., Douglass E. (Belle Mead, NJ); Dawson, John M. (Pacific Palisades, CA)



Ultraviolet observations of alpha Aurigae from Copernicus  

NASA Technical Reports Server (NTRS)

Emission lines of L-alpha (1215.67 A) and O VI (1031.94 A) were detected in the spectroscopic binary alpha Aur (Capella) with the Princeton experiment on Copernicus. Temperatures of the emitting regions are inferred to be in excess of 300,000 K. The temperature and emission measure are consistent with a variable source of soft X-rays. If the emission is attributed to the primary star (G5 III), the atmosphere is expanding with velocities of about 20-100 km/s. Such expansion can lead to material within the binary system. The density of interstellar hydrogen inferred from absorption of stellar L-alpha appears to be approximately 0.01 hydrogen atoms per cu cm.

Dupree, A. K.



Synthesis of peptide .alpha.-thioesters  


Disclosed herein is a new method for the solid phase peptide synthesis (SPPS) of C-terminal peptide .alpha. thioesters using Fmoc/t-Bu chemistry. This method is based on the use of an aryl hydrazine linker, which is totally stable to conditions required for Fmoc-SPPS. When the peptide synthesis has been completed, activation of the linker is achieved by mild oxidation. The oxidation step converts the acyl-hydrazine group into a highly reactive acyl-diazene intermediate which reacts with an .alpha.-amino acid alkylthioester (H-AA-SR) to yield the corresponding peptide .alpha.-thioester in good yield. A variety of peptide thioesters, cyclic peptides and a fully functional Src homology 3 (SH3) protein domain have been successfully prepared.

Camarero, Julio A. (Livermore, CA); Mitchell, Alexander R. (Livermore, CA); De Yoreo, James J. (Clayton, CA)



Alternating current long range alpha particle detector  


An alpha particle detector, utilizing alternating currents, which is capable of detecting alpha particles from distinct sources. The use of alternating currents allows use of simpler ac circuits which, in turn, are not susceptible to dc error components. It also allows the benefit of gas gain, if desired. In the invention, a voltage source creates an electric field between two conductive grids, and between the grids and a conductive enclosure. Air containing air ions created by collision with alpha particles is drawn into the enclosure and detected. In some embodiments, the air flow into the enclosure is interrupted, creating an alternating flow of ions. In another embodiment, a modulated voltage is applied to the grid, also modulating the detection of ions.

MacArthur, D.W.; McAtee, J.L.



Alternating current long range alpha particle detector  


An alpha particle detector, utilizing alternating currents, whcih is capable of detecting alpha particles from distinct sources. The use of alternating currents allows use of simpler ac circuits which, in turn, are not susceptible to dc error components. It also allows the benefit of gas gain, if desired. In the invention, a voltage source creates an electric field between two conductive grids, and between the grids and a conductive enclosure. Air containing air ions created by collision with alpha particles is drawn into the enclosure and detected. In some embodiments, the air flow into the enclosure is interrupted, creating an alternating flow of ions. In another embodiment, a modulated voltage is applied to the grid, also modulating the detection of ions.

MacArthur, Duncan W. (Los Alamos, NM); McAtee, James L. (Los Alamos, NM)



Lyman-alpha imagery of Comet Kohoutek  

NASA Technical Reports Server (NTRS)

Electrographic imagery of Comet Kohoutek in the 1100-1500 A wavelength range was obtained from a sounding rocket on Jan. 8, 1974, and from the Skylab space station on 13 occasions between Nov. 26, 1973 and Feb. 2, 1974. These images are predominantly due to Lyman-alpha (1216 A) emission from the hydrogen coma of the comet. The rocket pictures have been calibrated for absolute sensitivity and a hydrogen production rate has been determined. However, the Skylab camera suffered degradation of its sensitivity during the mission, and its absolute sensitivity for each observation can only be estimated by comparison of the comet images with those taken by the rocket camera, with imagery of the geocoronal Lyman-alpha glow, of the moon in reflected Lyman-alpha, and of ultraviolet-bright stars. The rocket and geocoronal comparisons are used to derive a preliminary, qualitative history of the development of the cometary hydrogen coma and the associated hydrogen production rate.

Carruthers, G. R.; Opal, C. B.; Page, T. L.; Meier, R. R.; Prinz, D. K.