ERIC Educational Resources Information Center
Liu, Yan; Zumbo, Bruno D.
2007-01-01
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…
Bayesian Meta-Analysis of Cronbach's Coefficient Alpha to Evaluate Informative Hypotheses
ERIC Educational Resources Information Center
Okada, Kensuke
2015-01-01
This paper proposes a new method to evaluate informative hypotheses for meta-analysis of Cronbach's coefficient alpha using a Bayesian approach. The coefficient alpha is one of the most widely used reliability indices. In meta-analyses of reliability, researchers typically form specific informative hypotheses beforehand, such as "alpha of…
Bayesian meta-analysis of Cronbach's coefficient alpha to evaluate informative hypotheses.
Okada, Kensuke
2015-12-01
This paper proposes a new method to evaluate informative hypotheses for meta-analysis of Cronbach's coefficient alpha using a Bayesian approach. The coefficient alpha is one of the most widely used reliability indices. In meta-analyses of reliability, researchers typically form specific informative hypotheses beforehand, such as 'alpha of this test is greater than 0.8' or 'alpha of one form of a test is greater than the others.' The proposed method enables direct evaluation of these informative hypotheses. To this end, a Bayes factor is calculated to evaluate the informative hypothesis against its complement. It allows researchers to summarize the evidence provided by previous studies in favor of their informative hypothesis. The proposed approach can be seen as a natural extension of the Bayesian meta-analysis of coefficient alpha recently proposed in this journal (Brannick and Zhang, 2013). The proposed method is illustrated through two meta-analyses of real data that evaluate different kinds of informative hypotheses on superpopulation: one is that alpha of a particular test is above the criterion value, and the other is that alphas among different test versions have ordered relationships. Informative hypotheses are supported from the data in both cases, suggesting that the proposed approach is promising for application.
ERIC Educational Resources Information Center
Liu, Yan; Wu, Amery D.; Zumbo, Bruno D.
2010-01-01
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,…
Minimum Sample Size for Cronbach's Coefficient Alpha: A Monte-Carlo Study
ERIC Educational Resources Information Center
Yurdugul, Halil
2008-01-01
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…
Understanding a Widely Misunderstood Statistic: Cronbach's "Alpha"
ERIC Educational Resources Information Center
Ritter, Nicola L.
2010-01-01
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…
On the Use, the Misuse, and the Very Limited Usefulness of Cronbach's Alpha
ERIC Educational Resources Information Center
Sijtsma, Klaas
2009-01-01
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…
ERIC Educational Resources Information Center
Kistner, Emily O.; Muller, Keith E.
2004-01-01
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…
ERIC Educational Resources Information Center
Zinbarg, Richard E.; Revelle, William; Yovel, Iftah; Li, Wen
2005-01-01
We make theoretical comparisons among five coefficients--Cronbach's [alpha], Revelle's [beta], McDonald's [omega][sub h], and two alternative conceptualizations of reliability. Though many end users and psychometricians alike may not distinguish among these five coefficients, we demonstrate formally their nonequivalence. Specifically, whereas…
Treating Cronbach's Alpha Reliability Coefficients as Data in Counseling Research
ERIC Educational Resources Information Center
Helms, Janet E.; Henze, Kevin T.; Sass, Terry L.; Mifsud, Venus A.
2006-01-01
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…
On the relationship between coefficient alpha and composite reliability.
Peterson, Robert A; Kim, Yeolib
2013-01-01
Cronbach's coefficient alpha is the most widely used estimator of the reliability of tests and scales. However, it has been criticized as being a lower bound and hence underestimating true reliability. A popular alternative to coefficient alpha is composite reliability, which is usually calculated in conjunction with structural equation modeling. A quantitative analysis of 2,524 pairs of coefficient alpha and composite reliability values derived from empirical investigations revealed that although the average composite reliability value (.86) exceeded the average corresponding coefficient alpha value (.84), the difference was relatively inconsequential for practical applications such as meta-analysis.
Coefficient alpha and interculture test selection.
Thurber, Steven; Kishi, Yasuhiro
2014-04-01
The internal consistency reliability of a measure can be a focal point in an evaluation of the potential adequacy of an instrument for adaptation to another cultural setting. Cronbach's alpha (α) coefficient is often used as the statistical index for such a determination. However, alpha presumes a tau-equivalent test and may constitute an inaccurate population estimate for multidimensional tests. These notions are expanded and examined with a Japanese version of a questionnaire on nursing attitudes toward suicidal patients, originally constructed in Sweden using the English language. The English measure was reported to have acceptable internal consistency (α) albeit the dimensionality of the questionnaire was not addressed. The Japanese scale was found to lack tau-equivalence. An alternative to alpha, "composite reliability," was computed and found to be below acceptable standards in magnitude and precision. Implications for research application of the Japanese instrument are discussed.
Coefficient Alpha: A Reliability Coefficient for the 21st Century?
ERIC Educational Resources Information Center
Yang, Yanyun; Green, Samuel B.
2011-01-01
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…
ERIC Educational Resources Information Center
Raykov, Tenko; Marcoulides, George A.
2015-01-01
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…
Commentary on Coefficient Alpha: A Cautionary Tale
ERIC Educational Resources Information Center
Green, Samuel B.; Yang, Yanyun
2009-01-01
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…
Coefficient Alpha Bootstrap Confidence Interval under Nonnormality
ERIC Educational Resources Information Center
Padilla, Miguel A.; Divers, Jasmin; Newton, Matthew
2012-01-01
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…
Meta-Analysis of Coefficient Alpha
ERIC Educational Resources Information Center
Rodriguez, Michael C.; Maeda, Yukiko
2006-01-01
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…
ERIC Educational Resources Information Center
Zhang, Zhiyong; Yuan, Ke-Hai
2016-01-01
Cronbach's coefficient alpha is a widely used reliability measure in social, behavioral, and education sciences. It is reported in nearly every study that involves measuring a construct through multiple items. With non-tau-equivalent items, McDonald's omega has been used as a popular alternative to alpha in the literature. Traditional estimation…
Bayesian Meta-Analysis of Coefficient Alpha
ERIC Educational Resources Information Center
Brannick, Michael T.; Zhang, Nanhua
2013-01-01
The current paper describes and illustrates a Bayesian approach to the meta-analysis of coefficient alpha. Alpha is the most commonly used estimate of the reliability or consistency (freedom from measurement error) for educational and psychological measures. The conventional approach to meta-analysis uses inverse variance weights to combine…
Coefficient Alpha and Reliability of Scale Scores
ERIC Educational Resources Information Center
Almehrizi, Rashid S.
2013-01-01
The majority of large-scale assessments develop various score scales that are either linear or nonlinear transformations of raw scores for better interpretations and uses of assessment results. The current formula for coefficient alpha (a; the commonly used reliability coefficient) only provides internal consistency reliability estimates of raw…
Bayesian Statistical Inference for Coefficient Alpha. ACT Research Report Series.
ERIC Educational Resources Information Center
Li, Jun Corser; Woodruff, David J.
Coefficient alpha is a simple and very useful index of test reliability that is widely used in educational and psychological measurement. Classical statistical inference for coefficient alpha is well developed. This paper presents two methods for Bayesian statistical inference for a single sample alpha coefficient. An approximate analytic method…
ERIC Educational Resources Information Center
Wise, Steven L.; DeMars, Christine E.
2009-01-01
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…
ERIC Educational Resources Information Center
Green, Samuel B.; Yang, Yanyun
2015-01-01
In the lead article, Davenport, Davison, Liou, & Love demonstrate the relationship among homogeneity, internal consistency, and coefficient alpha, and also distinguish among them. These distinctions are important because too often coefficient alpha--a reliability coefficient--is interpreted as an index of homogeneity or internal consistency.…
Limitations of Coefficient Alpha as an Index of Test Unidimensionality
ERIC Educational Resources Information Center
Green, Samual B.; And Others
1977-01-01
Confusion in the literature between the concepts of internal consistency and homogeneity has led to a misuse of coefficient alpha as an index of item homogeneity. This misuse is discussed and several indices of item homogeneity derived from the model of common factor analysis are offered as alternatives. (Author/JKS)
ERIC Educational Resources Information Center
Davenport, Ernest C.; Davison, Mark L.; Liou, Pey-Yan; Love, Quintin U.
2015-01-01
This article uses definitions provided by Cronbach in his seminal paper for coefficient a to show the concepts of reliability, dimensionality, and internal consistency are distinct but interrelated. The article begins with a critique of the definition of reliability and then explores mathematical properties of Cronbach's a. Internal consistency…
Coefficient Alpha as an Estimate of Test Reliability under Violation of Two Assumptions.
ERIC Educational Resources Information Center
Zimmerman, Donald W.; And Others
1993-01-01
Coefficient alpha was examined through computer simulation as an estimate of test reliability under violation of two assumptions. Coefficient alpha underestimated reliability under violation of the assumption of essential tau-equivalence of subtest scores and overestimated it under violation of the assumption of uncorrelated subtest error scores.…
A reliability generalization study of coefficient alpha for the UCLA loneliness scale.
Vassar, Matt; Crosby, James W
2008-11-01
Loneliness is a psychological construct that has been reported in a variety of populations and associated with a number of other negative psychological problems. This study was an examination of coefficient alpha of a prominent measure of loneliness: the University of California, Los Angeles (UCLA) Loneliness Scale (Russell, Peplau, & Cutrona, 1980; Russell, 1996). We utilized reliability generalization to provide an aggregate estimate of the reliability of the scale over time and in a variety of populations as well as to assess and identify sampling and demographic characteristics associated with variability in coefficient alpha. Of the 213 studies examined, 80 had reported alpha estimates, and we used them in this analysis. We discuss conditions associated with variability in coefficient alpha along with pertinent implications for practice and future research.
A Comparison of Tests for Equality of Two or More Independent Alpha Coefficients
ERIC Educational Resources Information Center
Kim, Seonghoon; Feldt, Leonard S.
2008-01-01
This article extends the Bonett (2003a) approach to testing the equality of alpha coefficients from two independent samples to the case of m [greater than or equal] 2 independent samples. The extended Fisher-Bonett test and its competitor, the Hakstian-Whalen (1976) test, are illustrated with numerical examples of both hypothesis testing and power…
ERIC Educational Resources Information Center
Paek, Insu
2016-01-01
The effect of guessing on the point estimate of coefficient alpha has been studied in the literature, but the impact of guessing and its interactions with other test characteristics on the interval estimators for coefficient alpha has not been fully investigated. This study examined the impact of guessing and its interactions with other test…
Kirchner, J.J.; Acree, W.E. Jr.; Leo, A.J.; Gelli, G.
1985-10-01
Experimental octanol-water partition coefficients are reported for substituted alpha, N-diphenylnitrones and benzonitrile N-oxides. The results of these measurements are used to calculate the aromatic fragment constants pi HC = N(O)C6H5, pi C = N----O, fHC = N(O), and fC = N----O for the group contribution methods of Hansch and Leo.
Zhang, Bintuan; Dang, Bingrong; Wang, Zhuanzi; Wei, Wei; Li, Wenjian
2013-10-01
The skin tissue-equivalent slab reported in the International Commission on Radiological Protection (ICRP) Publication 116 to calculate the localised skin dose conversion coefficients (LSDCCs) was adopted into the Monte Carlo transport code Geant4. The Geant4 code was then utilised for computation of LSDCCs due to a circular parallel beam of monoenergetic electrons, protons and alpha particles <10 MeV. The computed LSDCCs for both electrons and alpha particles are found to be in good agreement with the results using the MCNPX code of ICRP 116 data. The present work thus validates the LSDCC values for both electrons and alpha particles using the Geant4 code.
Study of the absorption coefficient of alpha particles to lower hybrid waves in tokamak
Wang, Jianbing Zhang, Xianmei Yu, Limin Zhao, Xiang
2014-02-12
Part of the energy of the Lower Hybrid (LH) waves may be absorbed by the α 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 γ{sub α} of LH waves due to α particles. Results show that, the γ{sub α} increases with the parallel refraction index n{sub ∥} while deceases with increasing the frequency of LH waves ω{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 γ{sub α} 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, η ≈ 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.
Bidleman, Terry F; Nygren, Olle; Tysklind, Mats
2016-09-01
Partition coefficients of gaseous semivolatile organic compounds (SVOCs) between polyurethane foam (PUF) and air (KPA) are needed in the estimation of sampling rates for PUF disk passive air samplers. We determined KPA in field experiments by conducting long-term (24-48 h) air sampling to saturate PUF traps and shorter runs (2-4 h) to measure air concentrations. Sampling events were done at daily mean temperatures ranging from 1.9 to 17.5 °C. Target compounds were hexachlorobenzene (HCB), alpha-hexachlorocyclohexane (α-HCH), 2,4-dibromoanisole (2,4-DiBA) and 2,4,6-tribromoanisole (2,4,6-TriBA). KPA (mL g(-1)) was calculated from quantities on the PUF traps at saturation (ng g(-1)) divided by air concentrations (ng mL(-1)). Enthalpies of PUF-to-air transfer (ΔHPA, kJ mol(-1)) were determined from the slopes of log KPA/mL g(-1) versus 1/T(K) for HCB and the bromoanisoles, KPA of α-HCH was measured only at 14.3 to 17.5 °C and ΔHPA was not determined. Experimental log KPA/mL g(-1) at 15 °C were HCB = 7.37; α-HCH = 8.08; 2,4-DiBA = 7.26 and 2,4,6-TriBA = 7.26. Experimental log KPA/mL g(-1) were compared with predictions based on an octanol-air partition coefficient (log KOA) model (Shoeib and Harner, 2002a) and a polyparameter linear free relationship (pp-LFER) model (Kamprad and Goss, 2007) using different sets of solute parameters. Predicted KP values varied by factors of 3 to over 30, depending on the compound and the model. Such discrepancies provide incentive for experimental measurements of KPA for other SVOCs.
ERIC Educational Resources Information Center
Black, Ryan A.; Yang, Yanyun; Beitra, Danette; McCaffrey, Stacey
2015-01-01
Estimation of composite reliability within a hierarchical modeling framework has recently become of particular interest given the growing recognition that the underlying assumptions of coefficient alpha are often untenable. Unfortunately, coefficient alpha remains the prominent estimate of reliability when estimating total scores from a scale with…
A Monte Carlo Study of Eight Confidence Interval Methods for Coefficient Alpha
ERIC Educational Resources Information Center
Romano, Jeanine L.; Kromrey, Jeffrey D.; Hibbard, Susan T.
2010-01-01
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…
Wang, J.; Zhang, X. Yu, L.; Zhao, X.
2014-12-15
In tokamaks, fusion generated α particles may absorb lower hybrid (LH) wave energy, thus reducing the LH current drive efficiency. The absorption coefficient γ{sub α} of LH waves due to α particles changing with some typical parameters is calculated in this paper. Results show that γ{sub α} increases with the parallel refraction index n{sub ‖}, while decreases with the frequency of LH waves ω over a wide range. Higher background plasma temperature and toroidal magnetic field will increase the absorption. The absorption coefficient γ{sub α} increases with n{sub e} when n{sub e} ≤ 8 × 10{sup 19} m{sup −3}, while decreases with n{sub e} when n{sub e} becomes larger, and there is a peak value of γ{sub α} when n{sub e} ≈ 8 × 10{sup 19} m{sup −1} for the ITER-like scenario. The influence of spectral broadening in parametric decay instabilities on the absorption coefficient is evaluated. The value of γ{sub α} with n{sub ‖} being 2.5 is almost two times larger than that with n{sub ‖} 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.
NASA Technical Reports Server (NTRS)
Guiot, R.; Wunnenberg, H.
1980-01-01
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.
Tillmann, Ralf; Saathoff, Harald; Brauers, Theo; Kiendler-Scharr, Astrid; Mentel, Thomas F
2009-04-07
The absolute rate coefficient for the reaction of alpha-pinene with ozone was determined in the temperature range between 243 K and 303 K at atmospheric pressure. In total, 30 experiments were performed in the large (85 m3) temperature-controlled simulation chamber AIDA, where the concentrations of the reactants ozone and alpha-pinene were measured directly. An Arrhenius expression for the alpha-pinene + ozone reaction was derived with a pre-exponential factor of (1.4 +/- 0.4) x 10(-15) cm3 s(-1) and a temperature coefficient of (833 +/- 86) K. This rate coefficient is in good agreement (-5%) with the current IUPAC (IUPAC 2007) recommendation at 298 K. The IUPAC recommendation is significantly larger (+27%), around 243 K where the recommended values were extrapolated from higher temperatures. This finding is relevant for tropical regions where strong updrafts can rapidly transport reactive hydrocarbons like alpha-pinene from the boundary layer into the cold regions of the free troposphere.
Alpha's standard error (ASE): an accurate and precise confidence interval estimate.
Duhachek, Adam; Lacobucci, Dawn
2004-10-01
This research presents the inferential statistics for Cronbach's coefficient alpha on the basis of the standard statistical assumption of multivariate normality. The estimation of alpha's standard error (ASE) and confidence intervals are described, and the authors analytically and empirically investigate the effects of the components of these equations. The authors then demonstrate the superiority of this estimate compared with previous derivations of ASE in a separate Monte Carlo simulation. The authors also present a sampling error and test statistic for a test of independent sample alphas. They conclude with a recommendation that all alpha coefficients be reported in conjunction with standard error or confidence interval estimates and offer SAS and SPSS programming codes for easy implementation.
Tracy, Jessica L; Robins, Richard W; Sherman, Jeffrey W
2009-06-01
The present research surveyed a group of editors and editorial board members of personality and social psychology journals to examine the practice of psychological science in their field. Findings demonstrate that (a) although personality and social researchers tend to use many of the same approaches, methods, and procedures, they nonetheless show average differences in each of these domains, as well as in their overarching theoretical aims and perspectives; (b) these average differences largely conform to social and personality researchers' stereotypes about each subgroup; (c) despite their methodological and philosophical differences, the 2 subgroups study many of the same research topics; and (d) the structure of social-personality research practices can be characterized as having 2 independent factors, which closely correspond to L. J. Cronbach's (1957) correlational and experimental "streams of research."
Copeland, Kyle; Parker, Donald E; Friedberg, Wallace
2010-03-01
Conversion coefficients have been calculated for fluence to absorbed dose, fluence to effective dose and fluence to gray equivalent, for isotropic exposure to alpha particles in the energy range of 10 MeV to 1 TeV (0.01-1000 GeV). The coefficients were calculated using Monte Carlo transport code MCNPX 2.7.A and BodyBuilder 1.3 anthropomorphic phantoms modified to allow calculation of effective dose to a Reference Person using tissues and tissue weighting factors from 1990 and 2007 recommendations of the International Commission on Radiological Protection (ICRP) and gray equivalent to selected tissues as recommended by the National Council on Radiation Protection and Measurements. Coefficients for effective dose are within 30 % of those calculated using ICRP 1990 recommendations.
Delimiting Coefficient a from Internal Consistency and Unidimensionality
ERIC Educational Resources Information Center
Sijtsma, Klaas
2015-01-01
I discuss the contribution by Davenport, Davison, Liou, & Love (2015) in which they relate reliability represented by coefficient a to formal definitions of internal consistency and unidimensionality, both proposed by Cronbach (1951). I argue that coefficient a is a lower bound to reliability and that concepts of internal consistency and…
NASA Astrophysics Data System (ADS)
Yang, Jin-Wei; Gao, Yi-Tian; Wang, Qi-Min; Su, Chuan-Qi; Feng, Yu-Jie; Yu, Xin
2016-01-01
In this paper, a fourth-order variable-coefficient nonlinear Schrödinger equation is studied, which might describe a one-dimensional continuum anisotropic Heisenberg ferromagnetic spin chain with the octuple-dipole interaction or an alpha helical protein with higher-order excitations and interactions under continuum approximation. With the aid of auxiliary function, we derive the bilinear forms and corresponding constraints on the variable coefficients. Via the symbolic computation, we obtain the Lax pair, infinitely many conservation laws, one-, two- and three-soliton solutions. We discuss the influence of the variable coefficients on the solitons. With different choices of the variable coefficients, we obtain the parabolic, cubic, and periodic solitons, respectively. We analyse the head-on and overtaking interactions between/among the two and three solitons. Interactions between a bound state and a single soliton are displayed with different choices of variable coefficients. We also derive the quasi-periodic formulae for the three cases of the bound states.
ERIC Educational Resources Information Center
Romano, Jeanine L.; Kromrey, Jeffrey D.; Owens, Corina M.; Scott, Heather M.
2011-01-01
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…
ERIC Educational Resources Information Center
Padilla, Miguel A.; Divers, Jasmin
2016-01-01
Coefficient omega and alpha are both measures of the composite reliability for a set of items. Unlike coefficient alpha, coefficient omega remains unbiased with congeneric items with uncorrelated errors. Despite this ability, coefficient omega is not as widely used and cited in the literature as coefficient alpha. Reasons for coefficient omega's…
Components of Variance of Scales with a Bifactor Subscale Structure from Two Calculations of Alpha
ERIC Educational Resources Information Center
Andrich, David
2016-01-01
Since Cronbach's (1951) elaboration of a from its introduction by Guttman (1945), this coefficient has become ubiquitous in characterizing assessment instruments in education, psychology, and other social sciences. Also ubiquitous are caveats on the calculation and interpretation of this coefficient. This article summarizes a recent contribution…
Transport coefficients of gluonic fluid
Das, Santosh K.; Alam, Jan-e
2011-06-01
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}.
NASA Technical Reports Server (NTRS)
Roskam, J.
1972-01-01
Expressions are derived for computing the aerodynamic influence coefficient matrix for nonplanar wing-body-tail configurations. An aerodynamic influence coefficient is defined as the load in lbs. induced on a panel as a result of a unit angle of attack on another panel. Fuselage, wing and tail thickness are assumed to be small with the result that the thickness effect on the flow-field is negligible. The method for determining the aerodynamic influence coefficient matrix is based on the lifting solution to the small perturbation, steady potential flow equation.
Haldane exclusion statistics and second virial coefficient
Murthy, M.V.N.; Shankar, R. )
1994-06-06
We show that Haldane's new definition of statistics, when generalized to infinite dimensional Hilbert spaces, is determined by the high temperature limit of the second virial coefficient. We thus show that this exclusion statistics parameter [ital g] of anyone is nontrivial and is completely determined by its exchange statistics parameter [alpha]. We also compute [ital g] for quasiparticles in the Luttinger model and show that it is equal to [alpha].
Factor Scores, Structure Coefficients, and Communality Coefficients
ERIC Educational Resources Information Center
Goodwyn, Fara
2012-01-01
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…
INTERNAL CONVERSION COEFFICIENTS - HOW GOOD ARE THEY NOW?
KIBEDI,T.; BURROWS, T.W.; TRZHASKOVSKAYA, M.B.; NESTOR, JR., C.W.; DAVIDSON, P.M.
2007-04-22
Internal conversion coefficients involving atomic electrons (ICC) and electron-positron pairs (IPC) are often required to determine transition multipolarities and total transition rates. A new internal conversion coefficient data base, BrIcc has been developed which integrates a number of tabulations on ICC and IPC, as well as {Omega}(E0) electronic factors. To decide which theoretical internal conversion coefficient table to use, the accurately determined experimental {alpha}{sub K}, {alpha}{sub L}, {alpha}{sub Total} and {alpha}{sub K}/{alpha}{sub L} values were compared with the new Dirac-Fock calculations using extreme assumptions on the effect of the atomic vacancy. While the overall difference between experiment and theory is less than 1%, our analysis shows preference towards the so called ''Frozen Orbital'' approximation, which takes into account the effect of the atomic vacancy.
... conditions such as high blood pressure and benign prostatic hyperplasia. Find out more about this class of medication. ... these conditions: High blood pressure Enlarged prostate (benign prostatic hyperplasia) Though alpha blockers are commonly used to treat ...
... Alpha fetoprotein - series References Cunningham FG, Leveno KJ, Bloom SL, et al. Prenatal diagnosis and fetal therapy. In: Cunningham FG, Leveno KJ, Bloom SL, et al, eds. Williams Obstetrics . 23rd ed. ...
... an apparently normal individual has a child with hemoglobin H disease or alpha thalassemia minor. It can ... gene on one chromosome 25% 25% 25% 25% hemoglobin H disease there is a 25% chance with ...
The Diffusion of Antimony of Alpha Iron.
Diffusion coefficients of antimony in alpha iron were determined in the temperature range 700 to 900C using the residual activity method. Specimens...negligible effect on the diffusion of antomony in alpha iron . These results are discussed in relation to the phenomenon of temper brittleness in steels
Ultraprecise measurement of thermal coefficients of expansion.
Jacobs, S F; Bradford, J N; Berthold Iii, J W
1970-11-01
A novel method for determining thermal expansion coefficients has been devised. It is based on the dependence of Fabry-Perot resonances on the mirror separation. The expansion sample is formed into an etalon spacer, with highly reflecting endplates optically contacted to each end. The Fabry-Perot resonances are probed by variable radiofrequency sidebands derived from a frequency stabilized 633-nm He-Ne laser. A change in sample temperature DeltaT causes a change in interferometer length DeltaL, which shifts the resonance frequencies by Deltanu. Then alpha = (1/DeltaT)(DeltaL/L) = (1/DeltaT)(Deltanu/nu). alpha can be measured with precision limited ultimately by the stability of the stabilized laser (1:10(9) with presently available commercial lasers). alpha vs temperature has been measured for samples of Owens-Illinois Cer-Vit, Corning ULE silica, and Schott low expansion glass-ceramic.
Modified Biserial Correlation Coefficients.
ERIC Educational Resources Information Center
Kraemer, Helena Chmura
1981-01-01
Asymptotic distribution theory of Brogden's form of biserial correlation coefficient is derived and large sample estimates of its standard error obtained. Its relative efficiency to the biserial correlation coefficient is examined. Recommendations for choice of estimator of biserial correlation are presented. (Author/JKS)
Coefficients Alpha, Beta, Omega, and the glb: Comments on Sijtsma
ERIC Educational Resources Information Center
Revelle, William; Zinbarg, Richard E.
2009-01-01
There are three fundamental problems in Sijtsma ("Psychometrika," 2008): (1) contrary to the name, the glb is not the greatest lower bound of reliability but rather is systematically less than omega[subscript t] (McDonald, "Test theory: A unified treatment," Erlbaum, Hillsdale, 1999), (2) we agree with Sijtsma that when considering how well a test…
Coefficients of Effective Length.
ERIC Educational Resources Information Center
Edwards, Roger H.
1981-01-01
Under certain conditions, a validity Coefficient of Effective Length (CEL) can produce highly misleading results. A modified coefficent is suggested for use when empirical studies indicate that underlying assumptions have been violated. (Author/BW)
NASA Technical Reports Server (NTRS)
Snyder, G. Jeffrey (Inventor)
2015-01-01
A high temperature Seebeck coefficient measurement apparatus and method with various features to minimize typical sources of errors is described. Common sources of temperature and voltage measurement errors which may impact accurate measurement are identified and reduced. Applying the identified principles, a high temperature Seebeck measurement apparatus and method employing a uniaxial, four-point geometry is described to operate from room temperature up to 1300K. These techniques for non-destructive Seebeck coefficient measurements are simple to operate, and are suitable for bulk samples with a broad range of physical types and shapes.
JKTLD: Limb darkening coefficients
NASA Astrophysics Data System (ADS)
Southworth, John
2015-11-01
JKTLD outputs theoretically-calculated limb darkening (LD) strengths for equations (LD laws) which predict the amount of LD as a function of the part of the star being observed. The coefficients of these laws are obtained by bilinear interpolation (in effective temperature and surface gravity) in published tables of coefficients calculated from stellar model atmospheres by several researchers. Many observations of stars require the strength of limb darkening (LD) to be estimated, which can be done using theoretical models of stellar atmospheres; JKTLD can help in these circumstances.
Physical and chemical properties of human plasma alpha2-macroglobulin.
Hall, P K; Roberts, R C
1978-01-01
Alpha2-M (alpha2-macroglobulin) was purified from human plasma by two different procedures. As well as having no detectable impurities by the usual criteria for testing the homogeneity of protein preparations, these alpha2M preparations showed a single component, after reduction in urea, of 185000 daltons by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The molecular weight of the alpha2M was found to be 718000 by sedimentation equilibrium experiments using the gravimetrically determined -v of 0.731 ml/g. The interaction of several proteinases with alpha2M was studied by using a novel discontinuous polyacrylamide-gel system, which showed clear separation of the enzyme-complexed alpha2M from the free alpha2M. These studies indicated that urokinase, as well as trypsin, chymotrypsin, plasmin and thrombin forms complexes with alphaM. The cleavage of the 185000-dalton subunit to a 85000-dalton species on interaction of trypsin with alpha2M was demonstrated by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis after reduction of the alpha2M-trypsin complex in urea. The amino acid composition, carbohydrate content, absorption coefficient at 280 nm, the specific refractive increment and the sedimentation coefficient for these alpha2M preparations were measured. The stability of the trypsin-binding activity of the alpha2M preparations was also studied under several storage situations. Images Fig. 1. Fig. 2. Fig. 3. Fig. 6. PMID:80217
Ayala, S; Colomer, D; Aymerich, M; Pujades, A; Vives-Corrons, J L
1996-07-01
Several different deletions underlie the molecular basis of alpha-thalassemia. The most common alpha-thalassemia determinant in Spain is the rightward deletion (-alpha 3.7). To our knowledge, however, no cases of alpha-thalassemia due to nondeletional mutations have so far been described in this particular Mediterranean area. Here, we report the existence of nondeletional forms of alpha-thalassemia in ten Spanish families. The alpha 2-globin gene was characterized in ten unrelated patients and their relatives only when the presence of deletional alpha-thalassemia was ruled out. The alpha 2-globin gene analysis was performed using the polymerase chain reaction (PCR) followed by restriction enzyme analysis or by allelespecific priming. This allowed the identification of a 5-base pair (bp) deletion at the donor site of IVS I (alpha Hph alpha) in 9 cases and the alpha 2 initiation codon mutation (alpha Nco alpha) in one case. Although these alpha 2-globin gene mutations are found in other mediterranean areas, our results demonstrate their presence in the Spanish population and suggest that the alpha Hph alpha/alpha alpha genotype is probably the most common nondeletional form of alpha-thalassemia in Spain.
Prediction of Aerodynamic Coefficients using Neural Networks for Sparse Data
NASA Technical Reports Server (NTRS)
Rajkumar, T.; Bardina, Jorge; Clancy, Daniel (Technical Monitor)
2002-01-01
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.
Indirect band gap in alpha-ZrO2
Kwok, C.K.; Aita, C.R.
1990-08-01
Measurements of the absorption coefficient on the fundamental optical absorption edge of alpha ZrO2 show that an indirect interband transition at 4.70 eV precedes two previously reported direct transitions. This result is in agreement with recent theoretical calculations of the alpha ZrO2 band structure. (JS)
ERIC Educational Resources Information Center
Woodruff, David; Wu, Yi-Fang
2012-01-01
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;…
Ab initio alpha-alpha scattering.
Elhatisari, Serdar; Lee, Dean; Rupak, Gautam; Epelbaum, Evgeny; Krebs, Hermann; Lähde, Timo A; Luu, Thomas; Meißner, Ulf-G
2015-12-03
Processes such as the scattering of alpha particles ((4)He), the triple-alpha reaction, and alpha capture play a major role in stellar nucleosynthesis. In particular, alpha capture on carbon determines the ratio of carbon to oxygen during helium burning, and affects subsequent carbon, neon, oxygen, and silicon burning stages. It also substantially affects models of thermonuclear type Ia supernovae, owing to carbon detonation in accreting carbon-oxygen white-dwarf stars. In these reactions, the accurate calculation of the elastic scattering of alpha particles and alpha-like nuclei--nuclei with even and equal numbers of protons and neutrons--is important for understanding background and resonant scattering contributions. First-principles calculations of processes involving alpha particles and alpha-like nuclei have so far been impractical, owing to the exponential growth of the number of computational operations with the number of particles. Here we describe an ab initio calculation of alpha-alpha scattering that uses lattice Monte Carlo simulations. We use lattice effective field theory to describe the low-energy interactions of protons and neutrons, and apply a technique called the 'adiabatic projection method' to reduce the eight-body system to a two-cluster system. We take advantage of the computational efficiency and the more favourable scaling with system size of auxiliary-field Monte Carlo simulations to compute an ab initio effective Hamiltonian for the two clusters. We find promising agreement between lattice results and experimental phase shifts for s-wave and d-wave scattering. The approximately quadratic scaling of computational operations with particle number suggests that it should be possible to compute alpha scattering and capture on carbon and oxygen in the near future. The methods described here can be applied to ultracold atomic few-body systems as well as to hadronic systems using lattice quantum chromodynamics to describe the interactions of
Ab initio alpha-alpha scattering
NASA Astrophysics Data System (ADS)
Elhatisari, Serdar; Lee, Dean; Rupak, Gautam; Epelbaum, Evgeny; Krebs, Hermann; Lähde, Timo A.; Luu, Thomas; Meißner, Ulf-G.
2015-12-01
Processes such as the scattering of alpha particles (4He), the triple-alpha reaction, and alpha capture play a major role in stellar nucleosynthesis. In particular, alpha capture on carbon determines the ratio of carbon to oxygen during helium burning, and affects subsequent carbon, neon, oxygen, and silicon burning stages. It also substantially affects models of thermonuclear type Ia supernovae, owing to carbon detonation in accreting carbon-oxygen white-dwarf stars. In these reactions, the accurate calculation of the elastic scattering of alpha particles and alpha-like nuclei—nuclei with even and equal numbers of protons and neutrons—is important for understanding background and resonant scattering contributions. First-principles calculations of processes involving alpha particles and alpha-like nuclei have so far been impractical, owing to the exponential growth of the number of computational operations with the number of particles. Here we describe an ab initio calculation of alpha-alpha scattering that uses lattice Monte Carlo simulations. We use lattice effective field theory to describe the low-energy interactions of protons and neutrons, and apply a technique called the ‘adiabatic projection method’ to reduce the eight-body system to a two-cluster system. We take advantage of the computational efficiency and the more favourable scaling with system size of auxiliary-field Monte Carlo simulations to compute an ab initio effective Hamiltonian for the two clusters. We find promising agreement between lattice results and experimental phase shifts for s-wave and d-wave scattering. The approximately quadratic scaling of computational operations with particle number suggests that it should be possible to compute alpha scattering and capture on carbon and oxygen in the near future. The methods described here can be applied to ultracold atomic few-body systems as well as to hadronic systems using lattice quantum chromodynamics to describe the interactions of
alpha-Hexachlorocyclohexane (alpha-HCH)
Integrated Risk Information System (IRIS)
alpha - Hexachlorocyclohexane ( alpha - HCH ) ; CASRN 319 - 84 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Ass
NASA Astrophysics Data System (ADS)
Tanaka, Hiroaki; Takahashi, Sachiko; Yamanaka, Mari; Yoshizaki, Izumi; Sato, Masaru; Sano, Satoshi; Motohara, Moritoshi; Kobayashi, Tomoyuki; Yoshitomi, Susumu; Tanaka, Tetsuo; Fukuyama, Seijiro
2006-09-01
The diffusion coefficients of lysozyme and alpha-amylase were measured in the various polyethylene glycol (PEG) solutions. Obtained diffusion coefficients were studied with the viscosity coefficient of the solution. It was found that the diffusion process of the protein was suppressed with a factor of vγ, where ν is a relative viscosity coefficient of the PEG solution. The value of γ is -0.64 at PEG1500 for both proteins. The value increased to -0.48 at PEG8000 for lysozyme, while decreased to -0.72 for alpha-amylase. The equation of an approximate diffusion coefficient at certain PEG molecular weight and concentration was roughly obtained.
... Cosmetics Home Cosmetics Products & Ingredients Ingredients Alpha Hydroxy Acids Share Tweet Linkedin Pin it More sharing options ... for Industry: Labeling for Cosmetics Containing Alpha Hydroxy Acids The following information is intended to answer questions ...
Flux-carrying fermions and the second virial coefficient
Blum, T.; Hagen, C.R.; Ramaswamy, S. )
1990-02-12
The second virial coefficient {ital B}{sub 2} for a system of spin-one-half flux-carrying fermions is computed. It is found that there arise significant differences from known results for the corresponding spinless system. Apart from the existence of cusps and a restricted periodicity of {ital B}{sub 2} when viewed as a function of the flux parameter {alpha}, one obtains here the remarkable result that there exist discontinuities in {ital B}{sub 2} at all even, nonzero values of {alpha}.
ERIC Educational Resources Information Center
Soderblom, David R.
1987-01-01
Describes the Alpha Centauri star system, which is the closest star system to the sun. Discusses the difficulties associated with measurements involving Alpha Centauri, along with some of the recent advances in stellar seismology. Raises questions about the possibilities of planets around Alpha Centauri. (TW)
Alpha ash transport and ash control
Miley, G.H.; Hu, S.C.; Varadarajan, V.
1990-01-01
This paper discusses: thermal {alpha}-particle transport is a crucial issue in ash buildup. The transport will determine if buildup prevents ignition and if external control is necessary. Due to uncertainties in the transport coefficients, 1-1/2-D sensitivity study of the influence on the fusion power density is done using the BALDUR code. The Baldur simulations with varying diffusion coefficients for ash plasma are performed. The results of ash transport in the presence of sawteeth and varying edge conditions are discussed. Also, the nature of the fishbone oscillation in the presence of two hot species consisting of hot alphas and beam injected ions is discussed. The sawteeth and fishbones can be potential mechanisms for enhanced ash transport; the latter will indirectly influence the ash transport.
Alpha, Dimension-Free, and Model-Based Internal Consistency Reliability
ERIC Educational Resources Information Center
Bentler, Peter M.
2009-01-01
As pointed out by Sijtsma ("in press"), coefficient alpha is inappropriate as a single summary of the internal consistency of a composite score. Better estimators of internal consistency are available. In addition to those mentioned by Sijtsma, an old dimension-free coefficient and structural equation model based coefficients are…
NASA Technical Reports Server (NTRS)
Tripathi, A. K.; Singhal, R. P.; Khazanov, G. V.; Avanov, L. A.
2016-01-01
Electron pitch angle (D (alpha)) and momentum (D(pp)) diffusion coefficients have been calculated due to resonant interactions with electrostatic electron cyclotron harmonic (ECH) and whistler mode chorus waves. Calculations have been performed at two spatial locations L = 4.6 and 6.8 for electron energies 10 keV. Landau (n = 0) resonance and cyclotron harmonic resonances n = +/-1, +/-2,...+/-5 have been included in the calculations. It is found that diffusion coefficient versus pitch angle (alpha) profiles show large dips and oscillations or banded structures. The structures are more pronounced for ECH and lower band chorus (LBC) and particularly at location 4.6. Calculations of diffusion coefficients have also been performed for individual resonances. It is noticed that the main contribution of ECH waves in pitch angle diffusion coefficient is due to resonances n = +1 and n = +2. A major contribution to momentum diffusion coefficients appears from n = +2. However, the banded structures in D alpha and Dpp coefficients appear only in the profile of diffusion coefficients for n = +2. The contribution of other resonances to diffusion coefficients is found to be, in general, quite small or even negligible. For LBC and upper band chorus waves, the banded structures appear only in Landau resonance. The Dpp diffusion coefficient for ECH waves is one to two orders smaller than D alpha coefficients. For chorus waves, Dpp coefficients are about an order of magnitude smaller than D alpha coefficients for the case n does not = 0. In case of Landau resonance, the values of Dpp coefficient are generally larger than the values of D alpha coefficients particularly at lower energies. As an aid to the interpretation of results, we have also determined the resonant frequencies. For ECH waves, resonant frequencies have been estimated for wave normal angle 89 deg and harmonic resonances n = +1, +2, and +3, whereas for whistler mode waves, the frequencies have been calculated for angle
Interpreting EEG alpha activity.
Bazanova, O M; Vernon, D
2014-07-01
Exploring EEG alpha oscillations has generated considerable interest, in particular with regards to the role they play in cognitive, psychomotor, psycho-emotional and physiological aspects of human life. However, there is no clearly agreed upon definition of what constitutes 'alpha activity' or which of the many indices should be used to characterize it. To address these issues this review attempts to delineate EEG alpha-activity, its physical, molecular and morphological nature, and examine the following indices: (1) the individual alpha peak frequency; (2) activation magnitude, as measured by alpha amplitude suppression across the individual alpha bandwidth in response to eyes opening, and (3) alpha "auto-rhythmicity" indices: which include intra-spindle amplitude variability, spindle length and steepness. Throughout, the article offers a number of suggestions regarding the mechanism(s) of alpha activity related to inter and intra-individual variability. In addition, it provides some insights into the various psychophysiological indices of alpha activity and highlights their role in optimal functioning and behavior.
Cytoplasmic hydrogen ion diffusion coefficient.
al-Baldawi, N F; Abercrombie, R F
1992-01-01
The apparent cytoplasmic proton diffusion coefficient was measured using pH electrodes and samples of cytoplasm extracted from the giant neuron of a marine invertebrate. By suddenly changing the pH at one surface of the sample and recording the relaxation of pH within the sample, an apparent diffusion coefficient of 1.4 +/- 0.5 x 10(-6) cm2/s (N = 7) was measured in the acidic or neutral range of pH (6.0-7.2). This value is approximately 5x lower than the diffusion coefficient of the mobile pH buffers (approximately 8 x 10(-6) cm2/s) and approximately 68x lower than the diffusion coefficient of the hydronium ion (93 x 10(-6) cm2/s). A mobile pH buffer (approximately 15% of the buffering power) and an immobile buffer (approximately 85% of the buffering power) could quantitatively account for the results at acidic or neutral pH. At alkaline pH (8.2-8.6), the apparent proton diffusion coefficient increased to 4.1 +/- 0.8 x 10(-6) cm2/s (N = 7). This larger diffusion coefficient at alkaline pH could be explained quantitatively by the enhanced buffering power of the mobile amino acids. Under the conditions of these experiments, it is unlikely that hydroxide movement influences the apparent hydrogen ion diffusion coefficient. PMID:1617134
Rae, Gordon
2008-11-01
Several authors have suggested that prior to conducting a confirmatory factor analysis it may be useful to group items into a smaller number of item 'parcels' or 'testlets'. The present paper mathematically shows that coefficient alpha based on these parcel scores will only exceed alpha based on the entire set of items if W, the ratio of the average covariance of items between parcels to the average covariance of items within parcels, is greater than unity. If W is less than unity, however, and errors of measurement are uncorrelated, then stratified alpha will be a better lower bound to the reliability of a measure than the other two coefficients. Stratified alpha are also equal to the true reliability of a test when items within parcels are essentially tau-equivalent if one assumes that errors of measurement are not correlated.
Activation of human alpha1 and alpha2 homomeric glycine receptors by taurine and GABA.
De Saint Jan, D; David-Watine, B; Korn, H; Bregestovski, P
2001-09-15
1. Two ligand binding alpha subunits, alpha1 and alpha2, of the human (H) glycine receptor (GlyR) are involved at inhibitory synapses in the adult and neonatal spinal cord, respectively. The ability of homomeric alphaH1 and alphaH2 GlyRs to be activated by glycine, taurine and GABA was studied in Xenopus oocytes or in the human embryonic kidney HEK-293 cell line. 2. In outside-out patches from HEK cells, glycine, taurine and GABA activated both GlyRs with the same main unitary conductance, i.e. 85 +/- 3 pS (n = 6) for alphaH1, and 95 +/- 5 pS (n = 4) for alphaH2. 3. The sensitivity of both alphaH1 and alphaH2 GlyRs to glycine was highly variable. In Xenopus oocytes the EC50 for glycine (EC50gly) was between 25 and 280 microM for alphaH1 (n = 44) and between 46 and 541 microM for alphaH2 (n = 52). For both receptors, the highest EC50gly values were found on cells with low maximal glycine responses. 4. The actions of taurine and GABA were dependent on the EC50gly: (i) their EC50 values were linearly correlated to EC50gly, with EC50tau approximately 10 EC50gly and EC50GABA approximately 500-800 EC50gly; (ii) they could act either as full or weak agonists depending on the EC50gly. 5. The Hill coefficient (n(H)) of glycine remained stable regardless of the EC50gly whereas n(H) for taurine decreased with increasing EC50tau. 6. The degree of desensitization, evaluated by fast application of saturating concentrations of agonist on outside-out patches from Xenopus oocytes, was similar for glycine and taurine on both GlyRs and did not exceed 50 %. 7. Our data concerning the variations of EC50gly and the subsequent behaviour of taurine and GABA could be qualitatively described by the simple del Castillo-Katz scheme, assuming that the agonist gating constant varies whereas the binding constants are stable. However, the stability of the Hill coefficient for glycine was not explained by this model, suggesting that other mechanisms are involved in the modulation of EC50.
ALPHA CONTAMINATION MONITORING
This project was conducted to determine the alpha hazard existing in the vicinity of the missile launch pad following the destruction of a missile ...were used for plutonium particle collection. Because all warhead-carrying missiles were properly launched after Project 2.3 was approved, no alpha contamination data was obtained.
Functional constraints on phenomenological coefficients
NASA Astrophysics Data System (ADS)
Klika, Václav; Pavelka, Michal; Benziger, Jay B.
2017-02-01
Thermodynamic fluxes (diffusion fluxes, heat flux, etc.) are often proportional to thermodynamic forces (gradients of chemical potentials, temperature, etc.) via the matrix of phenomenological coefficients. Onsager's relations imply that the matrix is symmetric, which reduces the number of unknown coefficients is reduced. In this article we demonstrate that for a class of nonequilibrium thermodynamic models in addition to Onsager's relations the phenomenological coefficients must share the same functional dependence on the local thermodynamic state variables. Thermodynamic models and experimental data should be validated through consistency with the functional constraint. We present examples of coupled heat and mass transport (thermodiffusion) and coupled charge and mass transport (electro-osmotic drag). Additionally, these newly identified constraints further reduce the number of experiments needed to describe the phenomenological coefficient.
Imaging alpha particle detector
Anderson, David F.
1985-01-01
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.
Imaging alpha particle detector
Anderson, D.F.
1980-10-29
A method and apparatus for detecting and imaging alpha particles sources is described. A dielectric coated high voltage electrode and a tungsten wire grid 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 to be quantitatively or qualitatively analyzed. A thin polyester film window 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.
Bolton, Richard D.; MacArthur, Duncan W.
1996-01-01
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, R.D.; MacArthur, D.W.
1996-08-27
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.
Young, K.M.
1991-01-01
This paper will focus on the state of development of diagnostics which are expected to provide the information needed for {alpha}- physics studies in the future. Conventional measurement of detailed temporal and spatial profiles of background plasma properties in DT will be essential for such aspects as determining heating effectiveness, shaping of the plasma profiles and effects of MHD, but will not be addressed here. This paper will address (1) the measurement of the neutron source, and hence {alpha}-particle birth profile, (2) measurement of the escaping {alpha}-particles and (3) measurement of the confined {alpha}-particles over their full energy range. There will also be a brief discussion of (4) the concerns about instabilities being generated by {alpha}-particles and the methods necessary for measuring these effects. 51 refs., 10 figs.
Wrong Signs in Regression Coefficients
NASA Technical Reports Server (NTRS)
McGee, Holly
1999-01-01
When using parametric cost estimation, it is important to note the possibility of the regression coefficients having the wrong sign. A wrong sign is defined as a sign on the regression coefficient opposite to the researcher's intuition and experience. Some possible causes for the wrong sign discussed in this paper are a small range of x's, leverage points, missing variables, multicollinearity, and computational error. Additionally, techniques for determining the cause of the wrong sign are given.
Reexamination of the {alpha}-{alpha}''fishbone'' potential
Day, J. P.; McEwen, J. E.; Elhanafy, M.; Smith, E.; Woodhouse, R.; Papp, Z.
2011-09-15
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.
NASA Astrophysics Data System (ADS)
Indarsih, Indrati, Ch. Rini
2016-02-01
In this paper, we define variance of the fuzzy random variables through alpha level. We have a theorem that can be used to know that the variance of fuzzy random variables is a fuzzy number. We have a multi-objective linear programming (MOLP) with fuzzy random of objective function coefficients. We will solve the problem by variance approach. The approach transform the MOLP with fuzzy random of objective function coefficients into MOLP with fuzzy of objective function coefficients. By weighted methods, we have linear programming with fuzzy coefficients and we solve by simplex method for fuzzy linear programming.
Fisch, N. J.
2015-12-10
Alpha particles born through fusion reactions in a tokamak reactor tend to slow down on electrons, but that could take up to hundreds of milliseconds. Before that happens, the energy in these alpha particles can destabilize on collisionless timescales toroidal Alfven modes and other waves, in a way deleterious to energy confinement. However, it has been speculated that this energy might be instead be channeled into useful energy, so as to heat fuel ions or to drive current. Such a channeling needs to be catalyzed by waves Waves can produce diffusion in energy of the alpha particles in a way that is strictly coupled to diffusion in space. If these diffusion paths in energy-position space point from high energy in the center to low energy on the periphery, then alpha particles will be cooled while forced to the periphery. The energy from the alpha particles is absorbed by the wave. The amplified wave can then heat ions or drive current. This process or paradigm for extracting alpha particle energy collisionlessly has been called alpha channeling. While the effect is speculative, the upside potential for economical fusion is immense. The paradigm also operates more generally in other contexts of magnetically confined plasma.
Orthogonality of spherical harmonic coefficients
NASA Technical Reports Server (NTRS)
Mcleod, M. G.
1980-01-01
Orthogonality relations are obtained for the spherical harmonic coefficients of functions defined on the surface of a sphere. Following a brief discussion of the orthogonality of Fourier series coefficients, consideration is given to the values averaged over all orientations of the coordinate system of the spherical harmonic coefficients of a function defined on the surface of a sphere that can be expressed in terms of Legendre polynomials for the special case where the function is the sum of two delta functions located at two different points on the sphere, and for the case of an essentially arbitrary function. It is noted that the orthogonality relations derived have found applications in statistical studies of the geomagnetic field.
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Seebeck coefficient of one electron
Durrani, Zahid A. K.
2014-03-07
The Seebeck coefficient of one electron, driven thermally into a semiconductor single-electron box, is investigated theoretically. With a finite temperature difference ΔT 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 ΔT are calculated and a thermally driven Coulomb staircase is predicted. Single-electron Seebeck oscillations occur with increasing ΔT, as one electron at a time charges the box. A method is proposed for experimental verification of these effects.
Ludeman, Kate; Erlandson, Eddie
2004-05-01
Highly intelligent, confident, and successful, alpha males represent about 70% of all senior executives. Natural leaders, they willingly take on levels of responsibility most rational people would find overwhelming. But many of their quintessential strengths can also make alphas difficult to work with. Their self-confidence can appear domineering. Their high expectations can make them excessively critical. Their unemotional style can keep them from inspiring their teams. That's why alphas need coaching to broaden their interpersonal tool kits while preserving their strengths. Drawing from their experience coaching more than 1,000 senior executives, the authors outline an approach tailored specifically for the alpha. Coaches get the alpha's attention by inundating him with data from 360-degree feedback presented in ways he will find compelling--both hard-boiled metrics and vivid verbatim comments from colleagues about his strengths and weaknesses. A 360-degree assessment is a wake-up call for most alphas, providing undeniable proof that their behavior doesn't work nearly as well as they think it does. That paves the way for a genuine commitment to change. In order to change, the alpha must venture into unfamiliar--and often uncomfortable--psychological territory. He must admit vulnerability, accept accountability not just for his own work for others', connect with his underlying emotions, learn to motivate through a balance of criticism and validation, and become aware of unproductive behavior patterns. The goal of executive coaching is not simply to treat the alpha as an individual problem but to improve the entire team dynamic. Initial success creates an incentive to persevere, and the virtuous cycle reverberates throughout the entire organization.
alpha2-Adrenoreceptor antagonists.
Mayer, P; Imbert, T
2001-06-01
A review of the literature relating to the therapeutic potential of alpha2-adrenoceptor antagonists published between 1990 and 2000 is presented. Although extensively studied since the early 1970s in a wide spectrum of therapeutic applications, the distinction of alpha2-adrenoceptor subtypes and some emerging evidence concerning new applications in neurodegenerative disorders, such as Alzheimer's and Parkinson's diseases, obesity and schizophrenia, have refreshed an interest in this class of agents.
The megacycle, pulse-echo internal friction method has been used to measure carbon and nitrogen Snoek damping peaks in alpha - iron in the temperature range 300 to 400 C. The diffusion coefficient of nitrogen at 326 C so determined was in good agreement with the coefficient determined by a bulk desorption method. (Author)
Fisher, Ray, K.
2009-05-13
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.
Transport coefficients of He+ ions in helium
NASA Astrophysics Data System (ADS)
Johnsen, Rainer; Viehland, Larry; Gray, Benjamin; Wright, Timothy
2016-09-01
New experimental mobilities of 4He+ in 4He at 298.7 K, as a function of E/N, have been determined. Uncertainties in the mobilities were reduced to about 1% by using a shuttered drift tube. Comparison with previously measured values show that only one set of previous data is reliable. We demonstrate that the mobilities and diffusion coeffcients of 4He+ in 4He can be calculated over wide ranges of E/N with high precision if accurate potential energy curves are available for the X2Σu+ and A2Σg+ states, and if one takes into account resonant charge transfer and corrects for quantum-mechanical effects. Potentials, obtained by extrapolation of results from d-aug-cc-pVXZ (X =6,7) basis sets using the CASSCF +MRCISD approach were found to be in exceptionally close agreement with the best potentials available (separately) and with experiment, and those were subsequently used in a new computer program to determine semi-classical phase shifts and transport cross sections, from which the gaseous ion transport coefficients are determined. A new set of data for the mobilities of alpha particles (He2+) ions was obtained as a byproduct of the experiment, but the transport theory has not yet been completed.
The Mass-8 experiment -- Measuring the {beta}-{alpha} angular correlations
Amsbaugh, J.F.; Beck, M.; Braeckeleer, L. de; Storm, D.W.; Swanson, E.; Swartz, K.B.; Schagen, J.P.S. van; Wright, D.C.; Zhao, Z.
1997-12-31
The objective of the Mass-8 experiment is to perform a precision test of the conservation of the vector current hypothesis and a search for second class currents. The authors present preliminary data on the correlation coefficients of the {beta}-{alpha} angular correlations of the {beta}-delayed {alpha}-decays of {sup 8}Li and {sup 8}B.
NASA Technical Reports Server (NTRS)
Chandra, N.
1974-01-01
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.
Identities for generalized hypergeometric coefficients
Biedenharn, L.C.; Louck, J.D.
1991-01-01
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.
Effective Viscosity Coefficient of Nanosuspensions
NASA Astrophysics Data System (ADS)
Rudyak, V. Ya.; Belkin, A. A.; Egorov, V. V.
2008-12-01
Systematic calculations of the effective viscosity coefficient of nanosuspensions have been performed using the molecular dynamics method. It is established that the viscosity of a nanosuspension depends not only on the volume concentration of the nanoparticles but also on their mass and diameter. Differences from Einstein's relation are found even for nanosuspensions with a low particle concentration.
Integer Solutions of Binomial Coefficients
ERIC Educational Resources Information Center
Gilbertson, Nicholas J.
2016-01-01
A good formula is like a good story, rich in description, powerful in communication, and eye-opening to readers. The formula presented in this article for determining the coefficients of the binomial expansion of (x + y)n is one such "good read." The beauty of this formula is in its simplicity--both describing a quantitative situation…
Dependence of the elastic strain coefficient of copper on the pre-treatment
NASA Technical Reports Server (NTRS)
Kuntze, Wilhelm
1950-01-01
The effect of various pre-treatments on the elastic strain coefficient (alpha) (defined as the reciprocal of the modulus of elasticity E) (Epsilon) and on the mechanical hysteresis of copper has been investigated. Variables comprising the pre-treatments were pre-straining by stretching in a tensile testing machine and by drawing through a die, aging at room and elevated temperatures and annealing. The variation of the elastic strain coefficient with test stress was also investigated.
Keeton, S C; Mount, M E
1999-03-26
With the end of the Cold War and the associated limitations imposed on the nuclear weapons stockpile by strategic arms treaties, much has changed in the stockpile stewardship program. Weapons that were originally designed for stockpile lives on the order of 15 to 20 years are now being evaluated for much longer periods: in some cases as much as 60 years. As such, issues that were once considered to be of no consequence are being reexamined. Among these is the extent of the radiation dose received by secondary organics over time that results from the intrinsic alpha source of the weapon components. This report describes the results of work performed to estimate the alpha radiation deposition in the organic components of an LLNL system at specific points in its stockpile life. Included are discussions of the development of the intrinsic time- and energy-dependent alpha source term per unit mass, estimation of the effective source and absorber material thicknesses, development of a simplified model for the total intrinsic alpha source term and energy deposition in the absorber, and the alpha radiation deposition in the organic components of a selected LLNL weapon.
Transport coefficients of quantum plasmas
Bennaceur, D.; Khalfaoui, A.H. )
1993-09-01
Transport coefficients of fully ionized plasmas with a weakly coupled, completely degenerate electron gas and classical ions with a wide range of coupling strength are expressed within the Bloch transport equation. Using the Kohler variational principle the collision integral of the quantum Boltzmann equation is derived, which accounts for quantum effects through collective plasma oscillations. The physical implications of the results are investigated through comparisons with other theories. For practical applications, electrical and thermal conductivities are derived in simple analytical formulas. The relation between these two transport coefficients is expressed in an explicit form, giving a generalized Wiedemann-Franz law, where the Lorentz ratio is a dependent function of the coupling parameter and the degree of degeneracy of the plasma.
High temperature Seebeck coefficient metrology
Martin, J.; Tritt, T.; Uher, C.
2010-12-15
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.
Consistent transport coefficients in astrophysics
NASA Technical Reports Server (NTRS)
Fontenla, Juan M.; Rovira, M.; Ferrofontan, C.
1986-01-01
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.
Study of Dispersion Coefficient Channel
NASA Astrophysics Data System (ADS)
Akiyama, K. R.; Bressan, C. K.; Pires, M. S. G.; Canno, L. M.; Ribeiro, L. C. L. J.
2016-08-01
The issue of water pollution has worsened in recent times due to releases, intentional or not, of pollutants in natural water bodies. This causes several studies about the distribution of pollutants are carried out. The water quality models have been developed and widely used today as a preventative tool, ie to try to predict what will be the concentration distribution of constituent along a body of water in spatial and temporal scale. To understand and use such models, it is necessary to know some concepts of hydraulic high on their application, including the longitudinal dispersion coefficient. This study aims to conduct a theoretical and experimental study of the channel dispersion coefficient, yielding more information about their direct determination in the literature.
Portable vapor diffusion coefficient meter
Ho, Clifford K.
2007-06-12
An apparatus for measuring the effective vapor diffusion coefficient of a test vapor diffusing through a sample of porous media contained within a test chamber. A chemical sensor measures the time-varying concentration of vapor that has diffused a known distance through the porous media. A data processor contained within the apparatus compares the measured sensor data with analytical predictions of the response curve based on the transient diffusion equation using Fick's Law, iterating on the choice of an effective vapor diffusion coefficient until the difference between the predicted and measured curves is minimized. Optionally, a purge fluid can forced through the porous media, permitting the apparatus to also measure a gas-phase permeability. The apparatus can be made lightweight, self-powered, and portable for use in the field.
Neural Network Prediction of New Aircraft Design Coefficients
NASA Technical Reports Server (NTRS)
Norgaard, Magnus; Jorgensen, Charles C.; Ross, James C.
1997-01-01
This paper discusses a neural network tool for more effective aircraft design evaluations during wind tunnel tests. Using a hybrid neural network optimization method, we have produced fast and reliable predictions of aerodynamical coefficients, found optimal flap settings, and flap schedules. For validation, the tool was tested on a 55% scale model of the USAF/NASA Subsonic High Alpha Research Concept aircraft (SHARC). Four different networks were trained to predict coefficients of lift, drag, moment of inertia, and lift drag ratio (C(sub L), C(sub D), C(sub M), and L/D) from angle of attack and flap settings. The latter network was then used to determine an overall optimal flap setting and for finding optimal flap schedules.
Convection coefficients at building surfaces
NASA Astrophysics Data System (ADS)
Kammerud, R. C.; Altmayer, E.; Bauman, F. S.; Gadgil, A.; Bohn, M.
1982-09-01
Correlations relating the rate of heat transfer from the surfaces of rooms to the enclosed air are being developed, based on empirical and analytic examinations of convection in enclosures. The correlations express the heat transfer rate in terms of boundary conditions relating to room geometry and surface temperatures. Work to date indicates that simple convection coefficient calculation techniques can be developed, which significantly improve accuracy of heat transfer predictions in comparison with the standard calculations recommended by ASHRAE.
Lovin, J.K.; Haese, R.L.; Heatherly, R.D.; Hughes, S.E.; Ishee, J.S.; Pratt, S.M.; Smith, D.W.
1992-02-01
ALPHA is a powerful and versatile management information system (MIS) initiated and sponsored and by the Finance and Business Management Division of Oak Ridge National Laboratory, who maintain and develop it in concert with the Business Systems Division for its Information Center. A general-purpose MIS, ALPHA allows users to access System 1022 and System 1032 databases to obtain and manage information. From a personal computer or a data terminal, Energy Systems employees can use ALPHA to control their own report reprocessing. Using four general commands (Database, Select, Sort, and Report) they can (1) choose a mainframe database, (2) define subsets within it, (3) sequentially order a subset by one or more variables, and (4) generate a report with their own or a canned format.
The Apollo Alpha Spectrometer.
NASA Technical Reports Server (NTRS)
Jagoda, N.; Kubierschky, K.; Frank, R.; Carroll, J.
1973-01-01
Located in the Science Instrument Module of Apollo 15 and 16, the Alpha Particle Spectrometer was designed to detect and measure the energy of alpha particles emitted by the radon isotopes and their daughter products. The spectrometer sensor consisted of an array of totally depleted silicon surface barrier detectors. Biased amplifier and linear gate techniques were utilized to reduce resolution degradation, thereby permitting the use of a single 512 channel PHA. Sensor identification and in-flight radioactive calibration were incorporated to enhance data reduction.
Temperature Dependent Rate Coefficients for the OH + Pinonaldehyde Reaction
NASA Astrophysics Data System (ADS)
Davis, M. E.; Talukdar, R.; Notte, G.; Ellison, G. B.; Ravishankara, A. R.; Burkholder, J. B.
2005-12-01
The biogenic emission of monoterpenes is an important source of volatile organic compounds (VOCs) to the atmosphere, approximately 10% of the biogenic hydrocarbons emitted yearly. The oxidation of alpha-pinene, the most abundant monoterpene in the atmosphere, by OH leads to the formation of pinonaldehyde (3-acetyl-2,2-dimethyl-cyclobutyl-ethanal) as a major oxidation product formed in yields > 50%. The atmospheric oxidation of pinonaldehyde will impact radical cycling, ozone formation and air quality on a regional scale. Previous laboratory studies of the OH + pinonaldehyde rate coefficient have used relative rate methods and were limited to room temperature. The reported rate coefficients are in poor agreement with values ranging from 4.0 to 9.1 × 10-11 cm#3 molecule-1 s-1. In this study we have measured absolute rate coefficients to resolve these discrepancies and have extended the measurements to include the temperature dependence. The rate coefficient for the gas phase reaction of OH with pinonaldehyde was measured over the temperature range 297 to 374 K and between 55 and 96 Torr under pseudo first order conditions in OH. Laser-induced fluorescence (LIF) was used to monitor the OH radical which was produced by pulsed laser photolysis. The pinonaldehyde concentration was determined in situ using Fourier transform infrared (FTIR) and UV (185 nm) absorption spectroscopy. The rate coefficient for the OH + pinonaldehyde reaction will be presented. Our results will be compared with previous rate coefficient measurements and the discrepancies and the atmospheric implications of these measurements will be discussed.
ERIC Educational Resources Information Center
Czaja, Paul Clement
2006-01-01
The Alpha point of the authors' life as a Montessori educator began in 1959, when he was a graduate student studying philosophy at Fordham University in the Bronx, New York. While studying the works of the great American philosopher William James, the author came across the writings of Maria Montessori and immediately became captivated by her…
ERIC Educational Resources Information Center
Kerber, Robert C.; Fernando, Marian S.
2010-01-01
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…
Radial-velocity variations in Alpha Ori, Alpha Sco, and Alpha Her
Smith, M.A.; Patten, B.M.; Goldberg, L. Computer Sciences Corp., Seabrook, MD Iowa State Univ., Ames )
1989-12-01
Radial-velocity observations of Alpha Ori, Alpha Sco A, and Alpha Her A are used to study radial-velocity periodicities in M supergiants. The data refer to several metallic lines in the H-alpha region and to H-alpha itself. It is shown that Alpha Ori and Alpha Sco A have cycle lengths of about 1 yr and semiamplitudes of 2 km/s. It is suggested that many semiregular red supergiant varibles such as Alpha Ori may be heading toward chaos. All three stars show short-term stochastic flucutations with an amplitude of 1-2 km/s. It is found that the long-term variability of H-alpha velocities may be a consequence of intermittent failed ejections. 58 refs.
Summary of Alpha Particle Transport
Medley, S.S.; White, R.B.; Zweben, S.J.
1998-08-19
This paper summarizes the talks on alpha particle transport which were presented at the 5th International Atomic Energy Agency's Technical Committee Meeting on "Alpha Particles in Fusion Research" held at the Joint European Torus, England in September 1997.
HB Hillingdon [alpha46(CE4)Phe-->Val (alpha1 Or alpha2)]: a new alpha chain hemoglobin variant.
Babb, Anna; Solaiman, Susannah; Green, Brian N; Mantio, Debbie; Patel, Ketan
2009-01-01
Routine antenatal hemoglobinopathy screening detected a new alpha chain variant that eluted with Hb A(2) on cation exchange high performance liquid chromatography (HPLC) in a lady of Sri Lankan origin who had normal hematological indices. The mutation was identified by electrospray ionization mass spectrometry (ESI-MS) as alpha46(CE4)Phe-->Val, inferring that the variant was due to a single base change at codon 46 (TTC>GTC) of the alpha1- or alpha2-globin genes.
Birkenmeier, G; Kunath, M
1996-05-17
Alpha 2-macroglobulin (alpha 2-M) is a major proteinase inhibitor in human blood and tissue. Besides its antiproteolytic potential, alpha 2-M was found to modulate antigen- and mitogen-driven immune responses and cell growth by binding and transporting distinct cytokines, growth factors and hormones. The inhibitor is cleared from circulation by binding to a multifunctional cellular receptor present on different cell types. Alpha 2-M, as well as its receptor, are capable of binding a variety of ligands. In the present study we have applied aqueous two-phase systems to analyze the interaction of IL-1 beta and alpha 2-M receptor to different forms of alpha 2-M. The partition of IL-1 beta was changed by addition of transformed alpha 2-M to the two-phase systems rather than by the native inhibitor. The interaction between IL-1 beta and alpha 2-M was enhanced by divalent cations. In addition, the complex formation between 125I-labelled receptor and alpha 2-M could clearly be demonstrated by partitioning. In the presence of divalent cations, transformed alpha 2-M, in contrast to the native inhibitor, effectively changed the partition of the receptor. However, the observed alteration of the partition coefficient was found to be less compared with the values obtained by partitioning of the receptor in the presence of whole plasma containing the inhibitor in equivalent concentrations. The results indicate that other components of the plasma exist which competitively bind to the receptor but independent of Ca2+-ions.
Porcu, Patrizia; O'Buckley, Todd K; Alward, Sarah E; Marx, Christine E; Shampine, Lawrence J; Girdler, Susan S; Morrow, A Leslie
2009-01-01
The 3alpha,5alpha- and 3alpha,5beta-reduced derivatives of progesterone, deoxycorticosterone, dehydroepiandrosterone and testosterone enhance GABAergic neurotransmission and produce inhibitory neurobehavioral and anti-inflammatory effects. Despite substantial information on the progesterone derivative (3alpha,5alpha)-3-hydroxypregnan-20-one (3alpha,5alpha-THP, allopregnanolone), the physiological significance of the other endogenous GABAergic neuroactive steroids has remained elusive. Here, we describe the validation of a method using gas chromatography-mass spectrometry to simultaneously identify serum levels of the eight 3alpha,5alpha- and 3alpha,5beta-reduced derivatives of progesterone, deoxycorticosterone, dehydroepiandrosterone and testosterone. The method shows specificity, sensitivity and enhanced throughput compared to other methods already available for neuroactive steroid quantification. Administration of pregnenolone to rats and progesterone to women produced selective effects on the 3alpha,5alpha- and 3alpha,5beta-reduced neuroactive steroids, indicating differential regulation of their biosynthetic pathways. Pregnenolone administration increased serum levels of 3alpha,5alpha-THP (+1488%, p<0.001), (3alpha,5alpha)-3,21-dihydroxypregnan-20-one (3alpha,5alpha-THDOC, +205%, p<0.01), (3alpha,5alpha)-3-hydroxyandrostan-17-one (3alpha,5alpha-A, +216%, p<0.001), (3alpha,5alpha,17beta)-androstane-3,17-diol (3alpha,5alpha-A-diol, +190%, p<0.01). (3alpha,5beta)-3-hydroxypregnan-20-one (3alpha,5beta-THP) and (3alpha,5beta)-3-hydroxyandrostan-17-one (3alpha,5beta-A) were not altered, while (3alpha,5beta)-3,21-dihydroxypregnan-20-one (3alpha,5beta-THDOC) and (3alpha,5beta,17beta)-androstane-3,17-diol (3alpha,5beta-A-diol) were increased from undetectable levels to 271+/-100 and 2.4+/-0.9 pg+/-SEM, respectively (5/8 rats). Progesterone administration increased serum levels of 3alpha,5alpha-THP (+1806%, p<0.0001), 3alpha,5beta-THP (+575%, p<0.001), 3alpha,5alpha
The ALPHA Magnetic Spectrometer
NASA Astrophysics Data System (ADS)
Viertel, G. M.; Capell, M.
1998-12-01
The ALPHA Magnetic Spectrometer (AMS) will be the first large magnetic spectrometer in space. It is scheduled to be installed on the future International Space Station ALPHA (ISSA) in the year 2002 to perform measurements of the charged particle composition to answer fundamental questions in particle physics and astrophysics. Before installation on ISSA, AMS will fly on the shuttle DISCOVERY for a period of 10 days starting in May 1998. This will enable AMS to perform a test of the apparatus and first measurements. The AMS detector has five major components: A permanent NdFeB magnet, six planes of Silicon double-sided microstrip detectors, a plastic scintillator time of flight hodoscope, a plastic scintillator anticoincidence counter and an Aerogel Cherenkov threshold counter. In addition, there are electronics, support infrastructure and interfaces.
The emission coefficient of uranium plasmas
NASA Technical Reports Server (NTRS)
Schneider, R. T.; Campbell, H. D.; Mack, J. M.
1973-01-01
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.
Sorption of humic acids and alpha-endosulfan by clayminerals
Hengpraprom, S.; Lee, C.M.; Coates, R.T.
2005-02-18
Sorption of alpha-endosulfan by kaolinite andmontmorillonite alone and in the presence of sorbed and dissolved humicacid (HA) was investigated (pH 8 and 25oC). Three types of HA, Elliotsoil HA (EHA), Peat HA (PHA), and Summit Hill HA (SHHA), were used torepresent typical humic substances found in soils. For sorption of HA byeither mineral, Freundlich sorption coefficient (Kf) values appeared todecrease in the order of EHA>PHA>SHHA, which followedincreasing polarity (expressed as the O/C atomic ratio) and decreasingpercent-carbon content. For both clays, sorption of alpha-endosulfan bythe HA mineral complex was greater than for sorption by the clay alone.Sorption of alpha-endosulfan by the HA mineral complexes followed thesame order as the Kf of the HAs (EHA>PHA>SHHA). Based on theamount of HA adsorbed by each mineral, organic carbon partitioncoefficients (KOC) were determined for sorption of alpha-endosulfan bytwo of the HA mineral complexes. The value of KOC for alpha-endosulfansorption was greater for kaolinite EHA than kaolinite SHHA. However, theopposite trend was found with the montmorillonite HA complexes.Montmorillonite appeared to sorb alpha-endosulfan and/or HA with higheraffinity than kaolinite, which likely is due to its 2:1 layer structureand higher surface area. Sorption of endosulfan diol, a hydrolysisproduct, by the minerals was much less than the parentpesticide.
Standards for Standardized Logistic Regression Coefficients
ERIC Educational Resources Information Center
Menard, Scott
2011-01-01
Standardized coefficients in logistic regression analysis have the same utility as standardized coefficients in linear regression analysis. Although there has been no consensus on the best way to construct standardized logistic regression coefficients, there is now sufficient evidence to suggest a single best approach to the construction of a…
A Note on the Dynamic Correlation Coefficient.
1977-11-04
The use of the dynamic correlation coefficient as a test of spuriousness in longitudinal designs was examined. It was shown that given conditions of...spuriousness and perfect stationarity, the dynamic correlation coefficient was positively, rather than inversely, related to spuriousness. It was...recommended that the dynamic correlation coefficient not be used in the future as a test of spuriousness. (Author)
Soccer Ball Lift Coefficients via Trajectory Analysis
ERIC Educational Resources Information Center
Goff, John Eric; Carre, Matt J.
2010-01-01
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…
M-Bonomial Coefficients and Their Identities
ERIC Educational Resources Information Center
Asiru, Muniru A.
2010-01-01
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.
Rae, Gordon
2007-06-01
The relationship between stratified alpha (alpha(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 the strata. When the items within each stratum are essentially tau equivalent, these variances are 0, and alpha(s) and true reliability are equal, provided errors of measurement are uncorrelated. If errors of measurement are positively correlated and there is essential tau equivalence within strata, stratified alpha will overestimate reliability. These findings indicate that recent studies involving stratified alpha (A. Kamata, A. Turhan, & E. Darandari, 2003; H. G. Osburn, 2000) need to be interpreted with some degree of caution. Nevertheless, the hypothetical population data presented in this article suggest that under certain circumstances, stratified alpha can be considerably greater than alpha and closer to the true reliability. Because the former is easily computed, it is recommended that with stratified tests, practicing researchers should routinely calculate both alpha and stratified alpha coefficients.
ERIC Educational Resources Information Center
Rae, Gordon
2007-01-01
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…
Alpha models and boundary-layer turbulence
NASA Astrophysics Data System (ADS)
Cheskidov, Alexey
We study boundary-layer turbulence using the Navier-Stokes-alpha model obtaining an extension of the Prandtl equations for the averaged flow in a turbulent boundary layer. In the case of a zero pressure gradient flow along a flat plate, we derive a nonlinear fifth-order ordinary differential equation, an extension of the Blasius equation. We study it analytically and prove the existence of a two-parameter family of solutions satisfying physical boundary conditions. From this equation we obtain a theoretical prediction of the skin-friction coefficient in a wide range of Reynolds numbers based on momentum thickness, and deduce the maximal value of the skin-friction coefficient in the turbulent boundary layer. The two-parameter family of solutions to the equation matches experimental data in the transitional boundary layers with different free stream turbulence intensity. A one-parameter sub-family of solutions, obtained using our skin-friction coefficient law, matches experimental data in the turbulent boundary layer for moderately large Reynolds numbers.
NASA Technical Reports Server (NTRS)
Lenoble, J.; Pruvost, P.
1983-01-01
SAGE four-channel transmission profiles are inverted to retrieve the extinction profiles from which the aerosol Angstrom coefficient alpha is obtained. The procedure allows one to check the influence of the NO2 absorption profile, which is small below 25 km. The results compare well with those obtained by a completely different procedure at NASA Langley Research Center, and the main features of the alpha profiles seem to be significant, even considering the rather large error bars. The relation between the retrieved Angstrom coefficient, the particle effective radius and the asymmetry factor is considered.
Second virial coefficients for chain molecules
Bokis, C.P.; Donohue, M.D. . Dept. of Chemical Engineering); Hall, C.K. . Dept. of Chemical Engineering)
1994-01-01
The importance of having accurate second virial coefficients in phase equilibrium calculations, especially for the calculation of dew points, is discussed. The square-well potentials results in a simple but inaccurate equation for the second virial coefficient for small, spherical molecules such as argon. Here, the authors present a new equation for the second virial coefficient of both spherical molecules and chain molecules which is written in a form similar to that for the square-well potential. This new equation is accurate in comparison to Monte Carlo simulation data on second virial coefficients for square-well chain molecules and with second virial coefficients obtained from experiments on n-alkanes.
NASA Technical Reports Server (NTRS)
Torr, D. G.; Orsini, N.
1978-01-01
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).
Substitutional and Interstitial Diffusion in alpha2-Ti3Al(O)
NASA Technical Reports Server (NTRS)
Copland, Evan; Young, David J.; Gleeson, Brian; Jacobson, Nathan
2007-01-01
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.
Background canceling surface alpha detector
MacArthur, D.W.; Allander, K.S.; Bounds, J.A.
1996-06-11
A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone. 5 figs.
Background canceling surface alpha detector
MacArthur, Duncan W.; Allander, Krag S.; Bounds, John A.
1996-01-01
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.
Water transport by the bacterial channel alpha-hemolysin
NASA Technical Reports Server (NTRS)
Paula, S.; Akeson, M.; Deamer, D.
1999-01-01
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.
Are alpha-gliadins glycosylated?
Turner, J B; Garner, G V; Gordon, D B; Brookes, S J; Smith, C A
2002-02-01
Alpha-gliadins isolated by carboxymethylcellulose chromatography contain noncovalently bound glucose probably due to contaminating proteoglycans and to material shed from the column. Traces of carbohydrate remain strongly bound to alpha-gliadins even after harsh denaturation, but our results indicate alpha-gliadins are not glycoproteins. Suggestions that gliadins are glycoproteins are probably due to contamination with this glucose and the presence of these proteoglycans.
Long range alpha particle detector
MacArthur, D.W.; Wolf, M.A.; McAtee, J.L.; Unruh, W.P.; Cucchiara, A.L.; Huchton, R.L.
1993-02-02
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.
Investigating bias in squared regression structure coefficients
Nimon, Kim F.; Zientek, Linda R.; Thompson, Bruce
2015-01-01
The importance of structure coefficients and analogs of regression weights for analysis within the general linear model (GLM) has been well-documented. The purpose of this study was to investigate bias in squared structure coefficients in the context of multiple regression and to determine if a formula that had been shown to correct for bias in squared Pearson correlation coefficients and coefficients of determination could be used to correct for bias in squared regression structure coefficients. Using data from a Monte Carlo simulation, this study found that squared regression structure coefficients corrected with Pratt's formula produced less biased estimates and might be more accurate and stable estimates of population squared regression structure coefficients than estimates with no such corrections. While our findings are in line with prior literature that identified multicollinearity as a predictor of bias in squared regression structure coefficients but not coefficients of determination, the findings from this study are unique in that the level of predictive power, number of predictors, and sample size were also observed to contribute bias in squared regression structure coefficients. PMID:26217273
Investigating bias in squared regression structure coefficients.
Nimon, Kim F; Zientek, Linda R; Thompson, Bruce
2015-01-01
The importance of structure coefficients and analogs of regression weights for analysis within the general linear model (GLM) has been well-documented. The purpose of this study was to investigate bias in squared structure coefficients in the context of multiple regression and to determine if a formula that had been shown to correct for bias in squared Pearson correlation coefficients and coefficients of determination could be used to correct for bias in squared regression structure coefficients. Using data from a Monte Carlo simulation, this study found that squared regression structure coefficients corrected with Pratt's formula produced less biased estimates and might be more accurate and stable estimates of population squared regression structure coefficients than estimates with no such corrections. While our findings are in line with prior literature that identified multicollinearity as a predictor of bias in squared regression structure coefficients but not coefficients of determination, the findings from this study are unique in that the level of predictive power, number of predictors, and sample size were also observed to contribute bias in squared regression structure coefficients.
Gas-film coefficients for streams
Rathbun, R.E.; Tai, D.Y.
1983-01-01
Equations for predicting the gas-film coefficient for the volatilization of organic solutes from streams are developed. The film coefficient is a function of windspeed and water temperature. The dependence of the coefficient on windspeed is determined from published information on the evaporation of water from a canal. The dependence of the coefficient on temperature is determined from laboratory studies on the evaporation of water. Procedures for adjusting the coefficients for different organic solutes are based on the molecular diffusion coefficient and the molecular weight. The molecular weight procedure is easiest to use because of the availability of molecular weights. However, the theoretical basis of the procedure is questionable. The diffusion coefficient procedure is supported by considerable data. Questions, however, remain regarding the exact dependence of the film coefficint on the diffusion coefficient. It is suggested that the diffusion coefficient procedure with a 0.68-power dependence be used when precise estimate of the gas-film coefficient are needed and that the molecular weight procedure be used when only approximate estimates are needed.
ERIC Educational Resources Information Center
Green, Samuel B.; Yang, Yanyun
2009-01-01
A method is presented for estimating reliability using structural equation modeling (SEM) that allows for nonlinearity between factors and item scores. Assuming the focus is on consistency of summed item scores, this method for estimating reliability is preferred to those based on linear SEM models and to the most commonly reported estimate of…
A Reliability Generalization Meta-Analysis of Coefficient Alpha for the Maslach Burnout Inventory
ERIC Educational Resources Information Center
Wheeler, Denna L.; Vassar, Matt; Worley, Jody A.; Barnes, Laura L. B.
2011-01-01
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…
Modeling Solar Lyman Alpha Irradiance
NASA Technical Reports Server (NTRS)
Pap, J.; Hudson, H. S.; Rottman, G. J.; Willson, R. C.; Donnelly, R. F.; London, J.
1990-01-01
Solar Lyman alpha irradiance is estimated from various solar indices using linear regression analyses. Models developed with multiple linear regression analysis, including daily values and 81-day running means of solar indices, predict reasonably well both the short- and long-term variations observed in Lyman alpha. It is shown that the full disk equivalent width of the He line at 1083 nm offers the best proxy for Lyman alpha, and that the total irradiance corrected for sunspot effect also has a high correlation with Lyman alpha.
Alpha Kappa Alpha Sorority's Reading Improvement Program for Minorities.
ERIC Educational Resources Information Center
Marable, June Morehead
This document discusses the founding and establishment of Alpha Kappa Alpha Sorority's reading experience pilot project. The efforts of this project were aligned with those of Right to Read and Reading Is Fundamental (RIF). Because of the response from parents and children, plans are being made to increase present operations within the next…
Molecular characterization of alpha 1- and alpha 2-adrenoceptors.
Harrison, J K; Pearson, W R; Lynch, K R
1991-02-01
Three 'alpha 1-adrenoceptors' and three 'alpha 2-adrenoceptors' have now been cloned. How closely do these receptors match the native receptors that have been identified pharmacologically? What are the properties of these receptors, and how do they relate to other members of the cationic amine receptor family? Kevin Lynch and his colleagues discuss these questions in this review.
[Alpha fetoprotein in umbilical cord blood].
Guibaud, S; Bonnet, M; Thoulon, J M; Dorche, J; Dumont, M
1975-02-08
Quantitative measurement of alpha-foetoprotein was made on the cord blood of 158 new-born of gestational age ranging between 15 and 43 weeks. The technique used was that of simple radial immunodiffusion of Mancini which made possible the exact measurement of A.F.P. in all the specimens apart from 3. The correlation coefficient between the A.F.P. level in cord blood and gestational age is significant (r equals 0,85 for a risk p equals 0,001). However, the degree of difference at a given point in pregnancy and the difference in levels found in certain cases of twin pregnancies, suggest that factors other than gestational age (certain complications of pregnancy, for example) may influence foetal A,F.P.
Recursive prescription for logarithmic jet rate coefficients
NASA Astrophysics Data System (ADS)
Gerwick, Erik
2013-11-01
We derive a recursion relation for the analytic leading logarithmic coefficients of a final state gluon cascade. We demonstrate the potential of our method by analytically computing the rate coefficients for the emission of up to 80 gluons in both the exclusive-kt (Durham) and generalized inclusive-kt class of jet algorithms. There is a particularly simple form for the ratios of resolved coefficients. We suggest potential applications for our method including the efficient generation of shower histories.
46 CFR 45.55 - Freeboard coefficient.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 46 Shipping 2 2014-10-01 2014-10-01 false Freeboard coefficient. 45.55 Section 45.55 Shipping... § 45.55 Freeboard coefficient. (a) For ships less than 350 feet in length (L), the freeboard coefficient is P 1 in the formula: P 1=P+A[(L/D)-(L/D s)] where P is a factor, which is a function of...
46 CFR 45.55 - Freeboard coefficient.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 46 Shipping 2 2010-10-01 2010-10-01 false Freeboard coefficient. 45.55 Section 45.55 Shipping... § 45.55 Freeboard coefficient. (a) For ships less than 350 feet in length (L), the freeboard coefficient is P 1 in the formula: P 1=P+A[(L/D)-(L/D s)] where P is a factor, which is a function of...
46 CFR 45.55 - Freeboard coefficient.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 46 Shipping 2 2012-10-01 2012-10-01 false Freeboard coefficient. 45.55 Section 45.55 Shipping... § 45.55 Freeboard coefficient. (a) For ships less than 350 feet in length (L), the freeboard coefficient is P 1 in the formula: P 1=P+A[(L/D)-(L/D s)] where P is a factor, which is a function of...
46 CFR 45.55 - Freeboard coefficient.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 46 Shipping 2 2013-10-01 2013-10-01 false Freeboard coefficient. 45.55 Section 45.55 Shipping... § 45.55 Freeboard coefficient. (a) For ships less than 350 feet in length (L), the freeboard coefficient is P 1 in the formula: P 1=P+A[(L/D)-(L/D s)] where P is a factor, which is a function of...
46 CFR 45.55 - Freeboard coefficient.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 46 Shipping 2 2011-10-01 2011-10-01 false Freeboard coefficient. 45.55 Section 45.55 Shipping... § 45.55 Freeboard coefficient. (a) For ships less than 350 feet in length (L), the freeboard coefficient is P 1 in the formula: P 1=P+A[(L/D)-(L/D s)] where P is a factor, which is a function of...
Dohet-Eraly, J.; Baye, D.
2011-07-15
An effective nucleon-nucleon interaction adapted to cluster-model calculations of collisions is derived from the realistic Argonne potential AV18 with the unitary correlation operator method. The unitary correlation is determined from the {alpha}+{alpha} elastic phase shifts calculated in a cluster approach by the generator coordinate method coupled with the microscopic R-matrix method. With this interaction, the elastic phase shifts for the {alpha}+n, {alpha}+p, and {alpha}+{sup 3}He collisions are calculated within the same model. Without further adjustment, a good agreement with experimental data is obtained with a small model space.
Alpha-particle microdosimetry.
Chouin, Nicolas; Bardies, Manuel
2011-07-01
With the increasing availability of alpha emitters, targeted α-particle therapy has emerged as a solution of choice to treat haematological cancers and micrometastatic and minimal residual diseases. Alpha-particles are highly cytotoxic because of their high linear energy transfer (LET) and have a short range of a few cell diameters in tissue, assuring good treatment specificity. These radiologic features make conventional dosimetry less relevant for that context. Stochastic variations in the energy deposited in cell nuclei are important because of the microscopic target size, low number of α- particle traversals, and variation in LET along the α-particle track. Microdosimetry provides a conceptual framework that aims at a systematic analysis of the stochastic distribution of energy deposits in irradiated matter. The different quantities of microdosimetry and the different methods of microdosimetric calculations were described in the early eighties. Since then, numerous models have been published through the years and applied to analyse experimental data or to model realistic therapeutic situations. Major results have been an accurate description of the high toxicity of α-particles, and the description of the predominant effect of activity distribution at the cellular scale on toxicity or efficacy of potential targeted α-particle therapies. This last factor represents a major limitation to the use of microdosimetry in vivo because determination of the source - target distribution is complicated. The future contributions of microdosimetry in targeted α-particle therapy research will certainly depend on the ability to develop high-resolution detectors and on the implementation of pharmaco-kinetic models at the tumour microenvironment scale.
Gross alpha analytical modifications that improve wastewater treatment compliance
Tucker, B.J.; Arndt, S.
2007-07-01
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)
Gas phase hydrogen permeation in alpha titanium and carbon steels
NASA Technical Reports Server (NTRS)
Johnson, D. L.; Shah, K. K.; Reeves, B. H.; Gadgeel, V. L.
1980-01-01
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.
DFT CONFORMATIONAL STUDIES OF ALPHA-MALTOTRIOSE
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...
Prothymosin alpha in human blood.
Panneerselvam, C; Haritos, A A; Caldarella, J; Horecker, B L
1987-01-01
The major cross-reacting peptide in human plasma detected with a radioimmunoassay (RIA) for thymosin alpha 1 was identified as prothymosin alpha, based on its elution properties in gel-filtration chromatography and its amino acid composition after purification by HPLC. A small quantity (less than 10%) of the total cross-reacting material was recovered in fractions corresponding to lower molecular weight thymosin alpha 1-like peptides. The total quantity of cross-reacting material detected in human blood, expressed as thymosin alpha 1 equivalents, was 11-14 pmol/ml (approximately 90% was recovered in the leukocyte fraction, approximately 10% was in the plasma fraction, and 1-2% was in the erythrocyte fraction). The peptide present in leukocytes was also identified as prothymosin alpha. After correction for the 5-times lower molar reactivity of prothymosin alpha in the thymosin alpha 1 RIA employed in these experiments, we estimate that the content of prothymosin alpha in human blood is 55-70 pmol/ml (0.6-0.8 microgram/ml). The relatively small quantities recovered in the erythrocyte and plasma fractions may be attributed to contamination of the former by leukocytes or to leakage from leukocytes into the plasma. PMID:3474615
EEG Alpha Power and Intelligence.
ERIC Educational Resources Information Center
Doppelmayr, M.; Klimesch, W.; Stadler, W.; Pollhuber, D.; Heine, C.
2002-01-01
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)
Alpha particle emitters in medicine
Fisher, D.R.
1989-09-01
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.
The effect of core configuration on temperature coefficient of reactivity in IRR-1
Bettan, M.; Silverman, I.; Shapira, M.; Nagler, A.
1997-08-01
Experiments designed to measure the effect of coolant moderator temperature on core reactivity in an HEU swimming pool type reactor were performed. The moderator temperature coefficient of reactivity ({alpha}{sub {omega}}) was obtained and found to be different in two core loadings. The measured {alpha}{sub {omega}} of one core loading was {minus}13 pcm/{degrees}C at the temperature range of 23-30{degrees}C. This value of {alpha}{sub {omega}} is comparable to the data published by the IAEA. The {alpha}{sub {omega}} measured in the second core loading was found to be {minus}8 pcm/{degrees}C at the same temperature range. Another phenomenon considered in this study is core behavior during reactivity insertion transient. The results were compared to a core simulation using the Dynamic Simulator for Nuclear Power Plants. It was found that in the second core loading factors other than the moderator temperature influence the core reactivity more than expected. These effects proved to be extremely dependent on core configuration and may in certain core loadings render the reactor`s reactivity coefficient undesirable.
Nava, María Paulina; Ibarra, Bertha; Magaña, María Teresa; de la Luz Chávez, María; Perea, F Javier
2006-01-01
The aim of this study was to determine the frequency of alpha-globin gene mutations in three groups of Mexican unrelated individuals. The first two groups were normal and sickle cell trait individuals from the Costa Chica region, a place with a 12.8% frequency of HbS carriers, and the third group comprised of Mexican mestizo patients with beta-thalassemia. We searched for -alpha(3.7) and -alpha(4.2) alpha(+)-thalassemia deletion alleles, as well as the alpha alpha alpha(anti3.7) triplication through long-gap PCR. The alleles -alpha(3.7) and alpha alpha alpha(anti3.7) were found in the heterozygote state only; 19% of the normal subjects had the -alpha(3.7) allele, and 2% showed the alpha alpha alpha(anti3.7) allele. In individuals with the sickle cell trait, 17% had the -alpha(3.7) deletion, and the alpha alpha alpha(anti3.7) triplication was observed in 3% of these individuals. We revealed that 16% of the subjects with beta-thalassemia showed the -alpha(3.7) deletion and 28% the alpha alpha alpha(anti3.7) triplication. The -alpha(4.2) deletion was not detected in any individual. The frequency of the -alpha(3.7) allele was roughly the same in the three groups studied; this can be explained by the fact that the three groups have common genes from Africa and the Mediterranean, where a high prevalence of alpha(+)-thalassemia has been observed. To our knowledge, the frequency of alpha alpha alpha(anti3.7) triplication observed in the Mexican beta-thalassemia patients is the highest reported. As the -alpha(3.7) and alpha alpha alpha(anti3.7) alleles are very common in our selected populations, we believe that there is a need to investigate systematically the alpha-globin gene mutations in all hemoglobinopathies in the Mexican population.
Implications of NGA for NEHRP site coefficients
Borcherdt, Roger D.
2012-01-01
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.
Decay of (p,q)-Fourier coefficients.
Edmunds, David E; Gurka, Petr; Lang, Jan
2014-10-08
We show that essentially the speed of decay of the Fourier sine coefficients of a function in a Lebesgue space is comparable to that of the corresponding coefficients with respect to the basis formed by the generalized sine functions sin p,q .
A gain-coefficient switched Alexandrite laser
NASA Astrophysics Data System (ADS)
Lee, Chris J.; van der Slot, Peter J. M.; Boller, Klaus-J.
2013-01-01
We report on a gain-coefficient switched Alexandrite laser. An electro-optic modulator is used to switch between high and low gain states by making use of the polarization dependent gain of Alexandrite. In gain-coefficient switched mode, the laser produces 85 ns pulses with a pulse energy of 240 mJ at a repetition rate of 5 Hz.
Calculator program set up for film coefficients
Gracey, J.O.; Teter, D.L.
1982-11-15
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.
Estimation of the simple correlation coefficient.
Shieh, Gwowen
2010-11-01
This article investigates some unfamiliar properties of the Pearson product-moment correlation coefficient for the estimation of simple correlation coefficient. Although Pearson's r is biased, except for limited situations, and the minimum variance unbiased estimator has been proposed in the literature, researchers routinely employ the sample correlation coefficient in their practical applications, because of its simplicity and popularity. In order to support such practice, this study examines the mean squared errors of r and several prominent formulas. The results reveal specific situations in which the sample correlation coefficient performs better than the unbiased and nearly unbiased estimators, facilitating recommendation of r as an effect size index for the strength of linear association between two variables. In addition, related issues of estimating the squared simple correlation coefficient are also considered.
An agreement coefficient for image comparison
Ji, L.; Gallo, K.
2006-01-01
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.
NASA Technical Reports Server (NTRS)
1990-01-01
The eastern edge of Alpha Regio is shown in this image centered at 30 degrees south latitude and 11.8 degrees east longitude (longitude on Venus is measured from 0 degrees to 360 degrees east). Seven circular, dome-like hills, averaging 25 kilometers (15 miles) in diameter with maximum heights of 750 meters (2,475 feet) dominate the scene. These features are interpreted as very thick lava flows that came from an opening on the relatively level ground, which allowed the lava to flow in an even pattern outward from the opening. The complex fractures on top of the domes suggest that if the domes were created by lava flows, a cooled outer layer formed and then further lava flowing in the interior stretched the surface. The domes may be similar to volcanic domes on Earth. Another interpretation is that the domes are the result of molten rock or magma in the interior that pushed the surface layer upward. The near-surface magma then withdrew to deeper levels, causing the collapse and fracturing of the dome surface. The bright margins possibly indicate the presence of rock debris on the slopes of the domes. Some of the fractures on the plains cut through the domes, while others appear to be covered by the domes. This indicates that active processes pre date and post date the dome-like hills. The prominent black area in the northeast corner of the image is a data gap. North is at the top of the image.
Rao, P.N.; Damodaran, K.M.
1984-03-01
Starting from 11 beta-hydroxytestosterone, the synthesis of a strategic precursor, C-9 (11) unsaturated 5 alpha-androstane-3 alpha, 17 beta-diol 17-glucuronide (9a), for the preparation of 9 alpha,11 alpha-tritiated 5 alpha-androstane-3 alpha, 17 beta-diol 17-glucuronide has been achieved. The authors optimized the reaction conditions for catalytic reduction employing hydrogen and subsequent base hydrolysis followed by purification on Amberlite XAD-2 resin to obtain the saturated 5 alpha-androstane-3 alpha, 17 beta-diol 17-glucuronide.
Theoretical calculation of Joule-Thomson coefficient by using third virial coefficient
NASA Astrophysics Data System (ADS)
Mamedov, Bahtiyar Akber; Somuncu, Elif; Askerov, Iskender M.
2017-02-01
The Joule-Thomson coefficient has been theoretical investigated by using third virial coefficient. Established expressions enable us accurate and rapid calculations of Joule-Thomson coefficient. As seen from numerical results the analytical expressions for third virial coefficients are a very useful, giving a very fast method to calculate other thermodynamics properties of gasses. As an example, the calculation results have been successfully tested by using various literature data.
Alpha-particle spectrometer experiment
NASA Technical Reports Server (NTRS)
Gorenstein, P.; Bjorkholm, P.
1972-01-01
Mapping the radon emanation of the moon was studied to find potential areas of high activity by detection of radon isotopes and their daughter products. It was felt that based on observation of regions overflown by Apollo spacecraft and within the field of view of the alpha-particle spectrometer, a radon map could be constructed, identifying and locating lunar areas of outgassing. The basic theory of radon migration from natural concentrations of uranium and thorium is discussed in terms of radon decay and the production of alpha particles. The preliminary analysis of the results indicates no significant alpha emission.
Path-counting formulas for generalized kinship coefficients and condensed identity coefficients.
Cheng, En; Ozsoyoglu, Z Meral
2014-01-01
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.
Soccer ball lift coefficients via trajectory analysis
NASA Astrophysics Data System (ADS)
Goff, John Eric; Carré, Matt J.
2010-07-01
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 parameters that have not been obtained by today's wind tunnels. Our trajectory analysis technique is not only a valuable tool for professional sports scientists, it is also accessible to students with a background in undergraduate-level classical mechanics.
Spatial correlation coefficient images for ultrasonic detection.
Cepel, Raina; Ho, K C; Rinker, Brett A; Palmer, Donald D; Lerch, Terrence P; Neal, Steven P
2007-09-01
In ultrasonics, image formation and detection are generally based on signal amplitude. In this paper, we introduce correlation coefficient images as a signal-amplitude independent approach for image formation. The correlation coefficients are calculated between A-scans digitized at adjacent measurement positions. In these images, defects are revealed as regions of high or low correlation relative to the background correlations associated with noise. Correlation coefficient and C-scan images are shown to demonstrate flat-bottom-hole detection in a stainless steel annular ring and crack detection in an aluminum aircraft structure.
On the emission coefficient of uranium plasmas.
NASA Technical Reports Server (NTRS)
Schneider, R. T.; Campbell, H. D.; Mack, J. M.
1973-01-01
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.
Diffusion coefficients in leaflets of bilayer membranes.
Seki, Kazuhiko; Mogre, Saurabh; Komura, Shigeyuki
2014-02-01
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 interleaflet friction. We also show that the diffusion coefficients diverge in the absence of coupling between the bilayer and solvents, even when the interleaflet friction is taken into account. In order to corroborate our theory, the effect of the interleaflet friction on the correlated diffusion is examined.
Spreading coefficients of aliphatic hydrocarbons on water
Takii, Taichi; Mori, Y.H. . Dept. of Mechanical Engineering)
1993-11-01
Experiments have been performed to determine the equilibrium spreading coefficients of some aliphatic hydrocarbons (C[sub 6]C[sub 10]) on water. The thickness of a discrete lens of each hydrocarbon sample floating on a stagnant water pool was measured interferometrically and used to calculate the spreading coefficient of the hydrocarbon with the aid of Langmuir's capillarity theory. The dependences of the spreading coefficient, thus observed, on temperature (0--50 C) and on the number of carbon atoms in the hydrocarbon molecule are in qualitative agreement with the predictions based on the Lifshitz theory of van der Waals forces.
Taslim, M.E.; Li, T.; Spring, S.D.
1998-07-01
A liquid crystal technique was used to measure heat transfer coefficients in twelve test sections with square and trapezoidal cross-sectional areas representing blade midchord cooling cavities in a modern gas turbine. Full-length ribs were configured on suction side as well as pressure side walls while half-length ribs were mounted on partition walls between adjacent cooling cavities. Ribs were in staggered arrangements with a nominal blockage ratio of 22% and an angle of attack to the mainstream flow, {alpha}, of 90 deg. Heat transfer measurements were performed on the roughened walls with full-length as well as half-length ribs. Nusselt numbers, friction factors, and thermal performances of all geometries are compared. The most important conclusion of this study is that the roughening of the partition walls enhances the heat transfer coefficients on those walls but, more importantly, enhances heat transfer coefficients on the primary walls considerably.
Zaider, M.; Varma, N.
1996-06-01
We report a microdosimetric-based evaluation of the effects of domestic exposure to radon. The risk coefficients obtained here are based on the microdosimetry of radon progeny alpha particles, on a function q(y) for in vivo radiogenic neoplasia, and on scaling A-bomb results (epidemiology + microdosimetry) to radon exposure. We do not use miner data, nor do we invoke such notions as quality factors, dose equivalent or equivalent dose. With basal cells as targets our estimated risk coefficients are in good agreement with the miner data, and thus a quality factor of about 20 (as suggested by ICRP 60) is not unreasonable. However, if we take as targets the secretory cells our risk coefficients are twice as large as those reported by BEIR-IV. The main uncertainty in these estimates remains the dosimetric model. 35 refs., 4 figs., 2 tabs.
Alpha Magnetic Spectrometer (AMS) Overview
The Alpha Magnetic Spectrometer (AMS) is flying to the station on STS-134. The AMS experiment is a state-of-the-art particle physics detector being operated by an international team composed of 60 ...
Genetics Home Reference: alpha thalassemia
... a blood disorder that reduces the production of hemoglobin . Hemoglobin is the protein in red blood cells that ... alpha thalassemia , a reduction in the amount of hemoglobin prevents enough oxygen from reaching the body's tissues. ...
Frye, Cheryl A; Rhodes, Madeline E
2005-03-15
5 alpha-Pregnan-3 alpha-ol-20-one (3 alpha,5 alpha-THP), progesterone (P4)'s 5 alpha-reduced, 3 alpha-hydroxysteroid oxidoreduced product, facilitates lordosis of rodents in part via agonist-like actions at GABA(A)/benzodiazepine receptor complexes in the ventral tegmental area (VTA). Whether 3 alpha,5 alpha-THP influences another reproductively-relevant behavior, lateral displacement, of hamsters was investigated. Lateral displacement is the movement that female hamsters make with their perineum towards male-like tactile stimulation. This behavior facilitates, and is essential for, successful mating. Hamsters in behavioral estrus had greater lateral displacement responses when endogenous progestin levels were elevated compared to when progestin levels were lower. Administration of P4, a prohormone for 3 alpha,5 alpha-THP, dose-dependently (500 > 200 > 100, 50, or 0 microg) enhanced lateral displacement of ovariectomized hamsters that had been primed with SC estradiol benzoate (5 or 10 microg). Inhibiting P4's metabolism to 3 alpha,5 alpha-THP by co-administering finasteride, a 5 alpha-reductase inhibitor, or indomethacin, a 3 alpha-hydroxysteroid oxidoreductase inhibitor, either systemically or to the VTA, significantly decreased lateral displacement and midbrain progestin levels of naturally receptive or hormone-primed hamsters compared to controls. These data suggest that lateral displacement is progestin-sensitive and requires the formation of 3 alpha,5 alpha-THP in the midbrain VTA.
Friction coefficient dependence on electrostatic tribocharging
NASA Astrophysics Data System (ADS)
Burgo, Thiago A. L.; Silva, Cristiane A.; Balestrin, Lia B. S.; Galembeck, Fernando
2013-08-01
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.
Universal relations of transport coefficients from holography
Cherman, Aleksey; Nellore, Abhinav
2009-09-15
We show that there are universal high-temperature relations for transport coefficients of plasmas described by a wide class of field theories with gravity duals. These theories can be viewed as strongly coupled large-N{sub c} conformal field theories deformed by one or more relevant operators. The transport coefficients we study are the speed of sound and bulk viscosity, as well as the conductivity, diffusion coefficient, and charge susceptibility of probe U(1) charges. We show that the sound bound v{sub s}{sup 2}{<=}1/3 is satisfied at high temperatures in these theories and also discuss bounds on the diffusion coefficient, the conductivity, and the bulk viscosity.
Second virial coefficient of one dimensional gas
Mijatovic, M.
1982-08-01
The second virial coefficient of a one dimensional gas is calculated using the expressions for the scattering amplitude. The scattering amplitude is chosen in the form of rational function of wave vector.
Heat transfer coefficient of cryotop during freezing.
Li, W J; Zhou, X L; Wang, H S; Liu, B L; Dai, J J
2013-01-01
Cryotop is an efficient vitrification method for cryopreservation of oocytes. It has been widely used owing to its simple operation and high freezing rate. Recently, the heat transfer performance of cryotop was studied by numerical simulation in several studies. However, the range of heat transfer coefficient in the simulation is uncertain. In this study, the heat transfer coefficient for cryotop during freezing process was analyzed. The cooling rates of 40 percent ethylene glycol (EG) droplet in cryotop during freezing were measured by ultra-fast measurement system and calculated by numerical simulation at different value of heat transfer coefficient. Compared with the results obtained by two methods, the range of the heat transfer coefficient necessary for the numerical simulation of cryotop was determined, which is between 9000 W/(m(2)·K) and 10000 W/(m (2)·K).
Friction coefficient dependence on electrostatic tribocharging.
Burgo, Thiago A L; Silva, Cristiane A; Balestrin, Lia B S; Galembeck, Fernando
2013-01-01
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.
Transonic Blunt Body Aerodynamic Coefficients Computation
NASA Astrophysics Data System (ADS)
Sancho, Jorge; Vargas, M.; Gonzalez, Ezequiel; Rodriguez, Manuel
2011-05-01
In the framework of EXPERT (European Experimental Re-entry Test-bed) accurate transonic aerodynamic coefficients are of paramount importance for the correct trajectory assessment and parachute deployment. A combined CFD (Computational Fluid Dynamics) modelling and experimental campaign strategy was selected to obtain accurate coefficients. A preliminary set of coefficients were obtained by CFD Euler inviscid computation. Then experimental campaign was performed at DNW facilities at NLR. A profound review of the CFD modelling was done lighten up by WTT results, aimed to obtain reliable values of the coefficients in the future (specially the pitching moment). Study includes different turbulence modelling and mesh sensitivity analysis. Comparison with the WTT results is explored, and lessons learnt are collected.
Absorption coefficient instrument for turbid natural waters.
Friedman, E; Poole, L; Cherdak, A; Houghton, W
1980-05-15
An instrument has been developed that directly measures the multispectral absorption coefficient of turbid natural water. The design incorporates methods for compensation of variation in the internal light source intensity, correction of the spectrally dependent nature of the optical elements, and correction for variation in background light level. When used in conjunction with a spectrally matched total attenuation instrument, the spectrally dependent scattering coefficient can also be derived. Systematic errors associated with multiple scattering have been estimated using Monte Carlo techniques.
Concordance correlation coefficient applied to discrete data.
Carrasco, Josep L; Jover, Lluis
2005-12-30
In any field in which decisions are subject to measurements, interchangeability between the methods used to obtain these measurements is essential. To consider methods as interchangeable, a certain degree of agreement is needed between the measurements they provide. The concordance correlation coefficient is an index that assesses the strength of agreement and it has been widely applied in situations in which measurements are made on a continuous scale. Recently the concordance correlation coefficient has been defined as a specific intraclass correlation coefficient estimated by the variance components of a Normal-Normal mixed linear model. Although this coefficient was defined for the continuous scale case, it may also be used with a discrete scale. In this case the data are often transformed and normalized, and the concordance correlation is applied. This study discusses the expression of the concordance correlation coefficient for discrete Poisson data by means of the Poisson-Normal generalized linear mixed model. The behaviour of the concordance correlation coefficient estimate is assessed by means of a simulation study, in which the estimates were compared using four models: three Normal-Normal mixed models with raw data, log-transformed data and square-root transformed data, and the Poisson-Normal generalized linear mixed model. An example is provided in which two different methods are used to measure CD34+ cells.
Estimation of Internal Consistency Reliability When Test Parts Vary in Effective Length.
ERIC Educational Resources Information Center
Feldt, Leonard S.; Charter, Richard A.
2003-01-01
Evaluating a test's reliability often requires dividing it into 3 or more unequal parts, which causes violation of the tau equivalence assumption of Cronbach's alpha. This article presents a criterion for abandoning alpha and an approach for computing a more appropriate estimate of reliability, the Gilmer-Feldt coefficient. (Author)
[Terahertz time-domain spectroscopy of alpha endosulfan persistent organic pollutant].
Hou, Di-bo; Yue, Fei-heng; Kang, Xu-sheng; Huang, Ping-jie; Zhang, Guang-xin
2012-05-01
Frequency-dependent absorption coefficient spectrum and refractive index spectrum of alpha endosulfan, a kind of persistent organic pollutants, are presented in the terahertz frequency region by terahertz (THz) time-domain spectroscopy (TDS). The spectral features in the THz region have a number of unique characteristic absorption peaks. The result demonstrates that THz-TDS is a promising method to identify materials. Then we adopted density functional calculation method to analyze theoretic absorption coefficients of single alpha endosulfan molecule within 0.2-2 THz. The results show that absorption peaks at 1.68, 1.91 THz in theoretical calculation correspond to 1.7, 1.88 THz in the experiment. Finally, vibrational modes and approximate assignments were discussed, showing that these matched peaks are caused by intramolecular vibrational modes of alpha endosulfan. Others might be related to intermolecular vibrational modes or combined vibrational modes.
NEW SCALING FOR THE ALPHA EFFECT IN SLOWLY ROTATING TURBULENCE
Brandenburg, A.; Gressel, O.; Kaepylae, P. J.; Kleeorin, N.; Rogachevskii, I.; Mantere, M. J.
2013-01-10
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.
Mechanism of alpha-tocopheryl-phosphate (alpha-TP) transport across the cell membrane
Technology Transfer Automated Retrieval System (TEKTRAN)
We have reported that alpha-TP is synthesized and hydrolyzed in animal cells and tissues; it modulates also several cell functions (FRBM 39:970, and UBMB Life, 57:23, 2005). While it is similar to alpha-tocopherol (alpha-T), alpha-TP appears to be more potent than alpha-T in inhibiting cell prolifer...
Temporal correlation coefficient for directed networks.
Büttner, Kathrin; Salau, Jennifer; Krieter, Joachim
2016-01-01
Previous studies dealing with network theory focused mainly on the static aggregation of edges over specific time window lengths. Thus, most of the dynamic information gets lost. To assess the quality of such a static aggregation the temporal correlation coefficient can be calculated. It measures the overall possibility for an edge to persist between two consecutive snapshots. Up to now, this measure is only defined for undirected networks. Therefore, we introduce the adaption of the temporal correlation coefficient to directed networks. This new methodology enables the distinction between ingoing and outgoing edges. Besides a small example network presenting the single calculation steps, we also calculated the proposed measurements for a real pig trade network to emphasize the importance of considering the edge direction. The farm types at the beginning of the pork supply chain showed clearly higher values for the outgoing temporal correlation coefficient compared to the farm types at the end of the pork supply chain. These farm types showed higher values for the ingoing temporal correlation coefficient. The temporal correlation coefficient is a valuable tool to understand the structural dynamics of these systems, as it assesses the consistency of the edge configuration. The adaption of this measure for directed networks may help to preserve meaningful additional information about the investigated network that might get lost if the edge directions are ignored.
Computing spatial information from Fourier coefficient distributions.
Heinz, William F; Werbin, Jeffrey L; Lattman, Eaton; Hoh, Jan H
2011-05-01
The spatial relationships between molecules can be quantified in terms of information. In the case of membranes, the spatial organization of molecules in a bilayer is closely related to biophysically and biologically important properties. Here, we present an approach to computing spatial information based on Fourier coefficient distributions. The Fourier transform (FT) of an image contains a complete description of the image, and the values of the FT coefficients are uniquely associated with that image. For an image where the distribution of pixels is uncorrelated, the FT coefficients are normally distributed and uncorrelated. Further, the probability distribution for the FT coefficients of such an image can readily be obtained by Parseval's theorem. We take advantage of these properties to compute the spatial information in an image by determining the probability of each coefficient (both real and imaginary parts) in the FT, then using the Shannon formalism to calculate information. By using the probability distribution obtained from Parseval's theorem, an effective distance from the uncorrelated or most uncertain case is obtained. The resulting quantity is an information computed in k-space (kSI). This approach provides a robust, facile and highly flexible framework for quantifying spatial information in images and other types of data (of arbitrary dimensions). The kSI metric is tested on a 2D Ising model, frequently used as a model for lipid bilayer; and the temperature-dependent phase transition is accurately determined from the spatial information in configurations of the system.
Workshop on Precision Measurements of $\\alpha_s$
Bethke, Siegfried; Hoang, Andre H.; Kluth, Stefan; Schieck, Jochen; Stewart, Iain W.; Aoki, S.; Beneke, M.; Bethke, S.; Blumlein, J.; Brambilla, N.; Brodsky, S.; /MIT, LNS
2011-10-01
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.
Immunodiagnosis of alpha chain disease.
Doe, W F; Danon, F; Seligmann, M
1979-01-01
Since the early diagnosis of alpha chain disease (alphaCD)) is essential to successful treatment and to epidemiological studies, the available immunodiagnostic techniques were compared for their sensitivity, specificity and ease of performance on a panel of sixteen sera, comprising ten alphaCD sera and six control sera containing either IgA myeloma protein or high levels of polyclonal IgA. Immunoselection by immunoelectrophoresis into gel containing a specially developed anti-Fabalpha antiserum provided the most sensitive and specific detection system for alphaCD protein. The same technique using anti-light chain antiserum for immunoselection was also highly sensitive, but proved less specific, being prone to false positives with difficult IgA myeloma proteins. Somewhat less sensitive, but specific and simple to perform, was immunoelectrophoresis using an antiserum recognizing the conformational specificities of Fabalpha as well as those of the constant region of alpha chains. Immunoselection using the Ouchterlony or rocket techniques proved to be less sensitive and prone to false positives when some IgA myeloma sera were tested. Images FIG. 1 FIG. 2 FIG. 3 FIG. 4 FIG. 5 FIG. 6 FIG. 7 PMID:113152
Sadreazami, Hamidreza; Ahmad, M Omair; Swamy, M N S
2014-10-01
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 α 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 α = 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.
Parametric modeling of quantile regression coefficient functions.
Frumento, Paolo; Bottai, Matteo
2016-03-01
Estimating the conditional quantiles of outcome variables of interest is frequent in many research areas, and quantile regression is foremost among the utilized methods. The coefficients of a quantile regression model depend on the order of the quantile being estimated. For example, the coefficients for the median are generally different from those of the 10th centile. In this article, we describe an approach to modeling the regression coefficients as parametric functions of the order of the quantile. This approach may have advantages in terms of parsimony, efficiency, and may expand the potential of statistical modeling. Goodness-of-fit measures and testing procedures are discussed, and the results of a simulation study are presented. We apply the method to analyze the data that motivated this work. The described method is implemented in the qrcm R package.
Temperature coefficients of multijunction solar cells
NASA Technical Reports Server (NTRS)
Virshup, G. F.; Chung, B.-C.; Ladle Ristow, M.; Kuryla, M. S.; Brinker, D.
1990-01-01
Temperature coefficients measured in solar simulators with those measured under AM0 solar illumination are compared to illustrate the challenges in making these measurements. It is shown that simulator measurements of the short-circuit current (delta Jsc/delta T) are inaccurate due to the mismatch between the solar spectrum and the simulators at the bandgaps of the solar cells. Especially susceptible to error is the delta Jsc/delta T of cells which are components in monolithic multijunction solar cells, such as GaAs filtered by 1.93-eV AlGaAs, which has an AM0 coefficient of 6.82 micro-A/sq cm/deg C, compared to a Xenon simulator coefficient of 22.2 micro-A/sq cm/deg C.
Bioisosteric phentolamine analogs as selective human alpha(2)- versus alpha(1)-adrenoceptor ligands.
Bavadekar, Supriya A; Hong, Seoung-Soo; Lee, Sang-Ii; Miller, Duane D; Feller, Dennis R
2008-08-20
Phentolamine is known to act as a competitive, non-subtype-selective alpha-adrenoceptor antagonist. In an attempt to improve alpha(2)- versus alpha(1)-adrenoceptor selectivity and alpha(2)-adrenoceptor subtype-selectivity, two new chemical series of bioisosteric phentolamine analogs were prepared and evaluated. These compounds were evaluated for binding affinities on alpha(1)- (alpha(1A)-, alpha(1B)-, alpha(1D)-) and alpha(2)- (alpha(2A)-, alpha(2B)-, alpha(2C)-) adrenoceptor subtypes that had been stably expressed in human embryonic kidney and Chinese hamster ovary cell lines, respectively. Methylation of the phenolic hydroxy group and replacement of the 4-methyl group of phentolamine with varying lipophilic substituents yielded bioisosteric analogs selective for the alpha(2)- versus alpha(1)-adrenoceptors. Within the alpha(2)-adrenoceptors, these analogs bound with higher affinity at the alpha(2A)- and alpha(2C)-subtypes as compared to the alpha(2B)-subtype. In particular, the t-butyl analog was found to be the most selective, its binding at the alpha(2C)-adrenoceptor (Ki=3.6 nM) being 37- to 173-fold higher than that at the alpha(1)-adrenoceptors, and around 2- and 19-fold higher than at the alpha(2A)- and alpha(2B)-adrenoceptors, respectively. Data from luciferase reporter gene assays confirmed the functional antagonist activities of selected compounds from the bioisosteric series on human alpha(1A)- and alpha(2C)-adrenoceptors. Thus, the results with these bioisosteric analogs of phentolamine provide a lead to the rational design of potent and selective alpha(2)-adrenoceptor ligands that may be useful in improving the therapeutic profile of this drug class for human disorders.
Effect of Items Direction (Positive or Negative) on the Reliability in Likert Scale. Paper-11
ERIC Educational Resources Information Center
Gul, Showkeen Bilal Ahmad; Qasem, Mamun Ali Naji; Bhat, Mehraj Ahmad
2015-01-01
In this paper an attempt was made to analyze the effect of items direction (positive or negative) on the Alpha Cronbach reliability coefficient and the Split Half reliability coefficient in Likert scale. The descriptive survey research method was used for the study and sample of 510 undergraduate students were selected by used random sampling…
ERIC Educational Resources Information Center
Gadermann, Anne M.; Guhn, Martin; Zumbo, Bruno D.
2012-01-01
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…
Space Station alpha joint bearing
NASA Technical Reports Server (NTRS)
Everman, Michael R.; Jones, P. Alan; Spencer, Porter A.
1987-01-01
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.
An Examination of the Reliability of the Organizational Assessment Package (OAP).
1981-07-01
methods, primarily Kuder - Richardson 20 and 21 (KR20 and KR21) and Cronbach’s alpha. Of these four methods, two are appropriate in the present situation...lowers reliability coefficients (Cronbach, 1960). The split-half method, therefore, must use a formula such as the Spearman-Brown correction formula to...estimate the full-scale reliability from the half-scale coeffi- cient. The use of this formula adds more inconsistency, since it is only an estimate
Diffusion and transport coefficients in synthetic opals
Sofo, J. O.; Mahan, G. D.
2000-07-15
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.
Seebeck Coefficient Measured With Differential Heat Pulses
NASA Technical Reports Server (NTRS)
Zoltan, L.; Wood, C.; Stapfer, G.
1986-01-01
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.
Second virial coefficients of dipolar hard spheres.
Philipse, Albert P; Kuipers, Bonny W M
2010-08-18
An asymptotic formula is reported for the second virial coefficient B(2) of a dipolar hard-sphere (DHS) fluid, in zero external field, for strongly coupled dipolar interactions. This simple formula, together with the one for the weak-coupling B(2), provides an accurate prediction of the second virial coefficient for a wide range of dipole moments, including those that are experimentally accessible in magnetite ferrofluids. The weak-coupling B(2) also yields an estimate of the magnetic moment minimally needed for isotropic gas-liquid phase-separation, if any, in the DHS fluid.
Asymptotics of loop quantum gravity fusion coefficients
NASA Astrophysics Data System (ADS)
Alesci, Emanuele; Bianchi, Eugenio; Magliaro, Elena; Perini, Claudio
2010-05-01
The fusion coefficients from SO(3) to SO(4) play a key role in the definition of spin foam models for the dynamics in loop quantum gravity. In this paper we give a simple analytic formula of the Engle-Pereira-Rovelli-Livine fusion coefficients. We study the large spin asymptotics and show that they map SO(3) semiclassical intertwiners into SU(2)L × SU(2)R semiclassical intertwiners. This non-trivial property opens the possibility for an analysis of the semiclassical behavior of the model.
Absorption coefficient instrument for turbid natural waters
NASA Astrophysics Data System (ADS)
Friedman, E.; Cherdak, A.; Poole, L.; Houghton, W.
1980-05-01
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.
Absorption coefficient instrument for turbid natural waters
NASA Technical Reports Server (NTRS)
Friedman, E.; Cherdak, A.; Poole, L.; Houghton, W.
1980-01-01
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.
Onsager coefficients of a Brownian Carnot cycle
NASA Astrophysics Data System (ADS)
Izumida, Y.; Okuda, K.
2010-10-01
We study a Brownian Carnot cycle introduced by Schmiedl and Seifert [Europhys. Lett. 81, 20003 (2008)] from a viewpoint of the linear irreversible thermodynamics. By considering the entropy production rate of this cycle, we can determine thermodynamic forces and fluxes of the cycle and calculate the Onsager coefficients for general protocols, that is, arbitrary schedules to change the potential confining the Brownian particle. We show that these Onsager coefficients contain the information of the protocol shape and they satisfy the tight-coupling condition irrespective of whatever protocol shape we choose. These properties may give an explanation why the Curzon-Ahlborn efficiency often appears in the finite-time heat engines.
Shear viscosity coefficient of liquid lanthanides
Patel, H. P. Thakor, P. B. Prajapati, A. V.; Sonvane, Y. A.
2015-05-15
Present paper deals with the computation of shear viscosity coefficient (η) of liquid lanthanides. The effective pair potential v(r) is calculated through our newly constructed model potential. The Pair distribution function g(r) is calculated from PYHS reference system. To see the influence of local field correction function, Hartree (H), Tailor (T) and Sarkar et al (S) local field correction function are used. Present results are compared with available experimental as well as theoretical data. Lastly, we found that our newly constructed model potential successfully explains the shear viscosity coefficient (η) of liquid lanthanides.
NACA Physicist Studying Alpha Rays
NASA Technical Reports Server (NTRS)
1957-01-01
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.
Bremsstrahlung in {alpha} Decay Reexamined
Boie, H.; Scheit, H.; Jentschura, U. D.; Koeck, F.; Lauer, M.; Schwalm, D.; Milstein, A. I.; Terekhov, I. S.
2007-07-13
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.
Alpha Channeling in Mirror Machines
Fisch, Nathaniel J.
2014-07-16
This Final Report for DE-FG02-06ER54851, Alpha Channeling in Mirror Machines, was in fact submitted on April 9, 2010. Some confusion arose because it was submitted as an initial progress report on a related grant, Alpha Channeling in Open- System Magnetic Devices. The original text is reproduced below, except that the publication record is undated. Note that the articles published in 2009 and 2010 reflect work in fact done under DE-FG02-06ER54851.
Test chamber for alpha spectrometry
Larsen, Robert P.
1977-01-01
Alpha emitters for low-level radiochemical analysis by measurement of alpha spectra are positioned precisely with respect to the location of a surface-barrier detector by means of a chamber having a removable threaded planchet holder. A pedestal on the planchet holder holds a specimen in fixed engagement close to the detector. Insertion of the planchet holder establishes an O-ring seal that permits the chamber to be pumped to a desired vacuum. The detector is protected against accidental contact and resulting damage.
The alpha 4 integrin chain is a ligand for alpha 4 beta 7 and alpha 4 beta 1
1995-01-01
The heterodimeric alpha 4 integrins alpha 4 beta 7 lymphocyte Peyer's patch adhesion molecule ([LPAM]-1) and alpha 4 beta 1 (very late antigen-4) are cell surface adhesion molecules involved in lymphocyte trafficking and lymphocyte-cell and matrix interactions. Known cellular ligands include vascular cell adhesion molecule (VCAM)-1, which binds to alpha 4 beta 1 and alpha 4 beta 7, and the mucosal addressin cell adhesion molecule (MAdCAM)-1, which binds to alpha 4 beta 7. Here we show that the alpha 4 chain of these integrins can itself serve as a ligand. The alpha 4 chain, immunoaffinity purified and immobilized on glass slides, binds thymocytes and T lymphocytes. Binding exhibits divalent cation requirements and temperature sensitivity which are characteristic of integrin-mediated interactions, and is specifically inhibited by anti-alpha 4 integrin antibodies, which exert their effect at the cell surface. Cells expressing exclusively alpha 4 beta 7 (TK-1) or alpha 4 beta 1 (L1-2) both bound avidly, whereas alpha 4-negative cells did not. A soluble 34-kD alpha 4 chain fragment retained binding activity, and it inhibited lymphocyte adhesion to alpha 4 ligands. It has been shown that alpha 4 integrin binding to fibronectin involves an leucine-aspartic acid-valine (LDV) motif in the HepII/IIICS region of fibronectin (CS-1 peptide), and homologous sequences are important in binding to VCAM-1 and MAdCAM-1. Three conserved LDV motifs occur in the extracellular sequence of alpha 4. A synthetic LDV-containing alpha 4- derived oligopeptide supports alpha 4-integrin-dependent lymphocyte adhesion and blocks binding to the 34-kD alpha 4 chain fragment. Our results suggest that alpha 4 beta 7 and alpha 4 beta 1 integrins may be able to bind to the alpha 4 subunit on adjacent cells, providing a novel mechanism for alpha 4 integrin-mediated and activation-regulated lymphocyte interactions during immune responses. PMID:7629498
Dai, Guang-Ming
2006-02-15
The set of Fourier series is discussed following some discussion of Zernike polynomials. Fourier transforms of Zernike polynomials are derived that allow for relating Fourier series expansion coefficients to Zernike polynomial expansion coefficients. With iterative Fourier reconstruction, Zernike representations of wavefront aberrations can easily be obtained from wavefront derivative measurements.
ERIC Educational Resources Information Center
Mohammed, Ahmed; Zeleke, Aklilu
2015-01-01
We introduce a class of second-order ordinary differential equations (ODEs) with variable coefficients whose closed-form solutions can be obtained by the same method used to solve ODEs with constant coefficients. General solutions for the homogeneous case are discussed.
ERIC Educational Resources Information Center
Marsh, S. Neil
This paper explains the meaning and use of three important factor analytic statistics: factor scores, factor structure coefficients, and communality coefficients. For the discussion, 301 observations of junior high school students 11 measured variables from a previous study are analyzed. While factors provide the researcher with general…
Computer programs for the concordance correlation coefficient.
Crawford, Sara B; Kosinski, Andrzej S; Lin, Hung-Mo; Williamson, John M; Barnhart, Huiman X
2007-10-01
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.
On Not Interpreting Coefficients: Comment on Holt.
ERIC Educational Resources Information Center
Wilson, Thomas P.
1979-01-01
A recent recommendation by Holt (EJ 200 576) that coefficients resulting from estimating log-linear and similar models should not be interpreted is argued to be based on lack of clarity about the substantive and theoretical importance of the choice between dummy and effect coding for categorical variables. (Author/GDC)
The Seebeck coefficient of superionic conductors
Mahan, G. D.
2015-01-28
We present a theory of the anomalous Seebeck coefficient found in the superionic conductor Cu{sub 2}Se. It has a phase transition at T = 400 K where the cations disorder but the anions do not. This disorder gives a temperature-dependent width to the electronic states in the conduction band. This width provides the anomalous Seebeck contribution.
Apparatus Measures Seebeck Coefficient And Resistivity
NASA Technical Reports Server (NTRS)
Zoltan, Leslie D.; Wood, Charles; Fleurial, Jean-Pierre; Liu, Yixin
1993-01-01
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.
A new method for calculating loss coefficients
Chang, Y.C.; Yang, W.T.; Liu, C.C. . Dept. of Electrical Engineering)
1994-08-01
A method is proposed which avoids many limitations associated with traditional B-coefficient loss coefficient calculation. The proposed method, unlike the traditional B-coefficient method, is very fast and can handle line outages. The method utilizes network sensitivity factors which are established from DC load flow solutions. Line outage distribution factors (ODF's) are formulated using changes in network power generations to simulate the outaged line from the network. The method avoids the use of complicated reference frame transformations based upon Kron's tensor analysis. The necessity of data normalization used in least squares and the evaluation of the slope of [theta][sub j] versus PG[sub n] is not necessary with the proposed method. Using IEEE standard 14-bus and 30-bus systems, the method's results are compared against results obtained from an AC load flow program (LFED). The method's solution speed is compared to that of the LFED method, the base case database method and the conventional B-coefficient method based on A[sub jn]-factor. The proposed method is easy to implement and, when compared to other methods, has exhibited good accuracy and rapid execution times. The method is well suited to on-line dispatch applications.
Experimental Influence Coefficients and Vibration Modes
NASA Technical Reports Server (NTRS)
Weidman, Deene J.; Kordes, Eldon E.
1959-01-01
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.
Static coefficient test method and apparatus
NASA Technical Reports Server (NTRS)
Haehner, C. L.; Tarpley, J. L. (Inventor)
1976-01-01
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.
Problems on Divisibility of Binomial Coefficients
ERIC Educational Resources Information Center
Osler, Thomas J.; Smoak, James
2004-01-01
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…
The Evolution of Pearson's Correlation Coefficient
ERIC Educational Resources Information Center
Kader, Gary D.; Franklin, Christine A.
2008-01-01
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…
The Seebeck coefficient of superionic conductors
NASA Astrophysics Data System (ADS)
Mahan, G. D.
2015-01-01
We present a theory of the anomalous Seebeck coefficient found in the superionic conductor Cu2Se. It has a phase transition at T = 400 K where the cations disorder but the anions do not. This disorder gives a temperature-dependent width to the electronic states in the conduction band. This width provides the anomalous Seebeck contribution.
Coefficient Omega Bootstrap Confidence Intervals: Nonnormal Distributions
ERIC Educational Resources Information Center
Padilla, Miguel A.; Divers, Jasmin
2013-01-01
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.…
Pressure-viscosity coefficient of biobased lubricants
Technology Transfer Automated Retrieval System (TEKTRAN)
Film thickness is an important tribological property that is dependent on the combined effect of lubricant properties, material property of friction surfaces, and the operating conditions of the tribological process. Pressure-viscosity coefficient (PVC) is one of the lubricant properties that influe...
NASA Technical Reports Server (NTRS)
Harf, F. H.
1981-01-01
Specimens of gamma/gamma-prime-alpha (Mo) eutectic alloy were thermally cycled or isothermally exposed at temperatures of 1075 to 1100 C. Transmission electron microscopy examination of cycled specimens indicated that even an exposure of 10 minutes effected noticeable changes in the shape of the alpha phase, and that the changes were cumulative as more cycles were added. The cross sections of fine, smooth fibers changed from rectangles to octagons, while lamellae and irregular shapes spheroidized. These effects are attributed to the differences in thermal expansion coefficients between the alpha phase and the gamma/gamma-prime matrix, and to the higher diffusion rates prevailing at elevated temperatures. Where the configuration of the alpha phase is a simple shape, such as a fiber, increasing the temperature eventually brings about a stress free interface between the alpha phase and the matrix by differential thermal expansion. Where the shape of the alpha phase is more complex, a stressed interface persists to higher temperatures where diffusion produces the more drastic morphological changes.
Layer coefficients for NHDOT pavement materials
NASA Astrophysics Data System (ADS)
Janoo, Vincent C.
1994-09-01
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.
Hall coefficient measurement for nondestructive materials characterization
NASA Astrophysics Data System (ADS)
Nagy, Peter B.
2013-01-01
Although Hall detectors are widely used for magnetic flux density measurements in numerous electromagnetic NDE applications, measurement of the Hall coefficient of metals and their alloys for NDE purposes has not been successfully attempted before. While other intrinsic electric properties, such as electric conductivity and, to a lesser degree, thermoelectric power, are widely used for NDE, Hall coefficient measurements have never been really considered mainly because the measurements are rather difficult to carry out, especially in high-conductivity materials. In contrast to electric conductivity, the Hall coefficient is influenced mainly by the concentration density of the free charge carriers, i.e., electrons in metals, and not so much by their mobility, therefore it could be a valuable addition to our NDE arsenal. We modified the alternating current potential drop (ACPD) method with square-electrode configuration by adding an external bias magnetic field modulation to measure the Hall coefficient. The presence of such a bias field violates the Reciprocity Theorem unless the sign of the magnetic field is switched between the two measurements, which can be exploited to measure the Hall coefficient in the presence of other variations that would otherwise hide it. This new experimental method was tested on paramagnetic alloys and yielded a ±4% reproducibility that probably could be further improved by additional development efforts. As a first step towards illustrating some of the potential applications of this new technique, we have done reversible applied stress measurements in Al 1100 plates and found the sensitivity of the technique to elastic strain surprisingly high.
Alpha proton x ray spectrometer
NASA Technical Reports Server (NTRS)
Rieder, Rudi; Waeke, H.; Economou, T.
1994-01-01
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.
Sparse Coding for Alpha Matting.
Johnson, Jubin; Varnousfaderani, Ehsan Shahrian; Cholakkal, Hisham; Rajan, Deepu
2016-07-01
Existing color sampling-based alpha matting methods use the compositing equation to estimate alpha at a pixel from the pairs of foreground ( F ) and background ( B ) samples. The quality of the matte depends on the selected ( F,B ) pairs. In this paper, the matting problem is reinterpreted as a sparse coding of pixel features, wherein the sum of the codes gives the estimate of the alpha matte from a set of unpaired F and B samples. A non-parametric probabilistic segmentation provides a certainty measure on the pixel belonging to foreground or background, based on which a dictionary is formed for use in sparse coding. By removing the restriction to conform to ( F,B ) pairs, this method allows for better alpha estimation from multiple F and B samples. The same framework is extended to videos, where the requirement of temporal coherence is handled effectively. Here, the dictionary is formed by samples from multiple frames. A multi-frame graph model, as opposed to a single image as for image matting, is proposed that can be solved efficiently in closed form. Quantitative and qualitative evaluations on a benchmark dataset are provided to show that the proposed method outperforms the current stateoftheart in image and video matting.
Sparse Coding for Alpha Matting.
Johnson, Jubin; Varnousfaderani, Ehsan; Cholakkal, Hisham; Rajan, Deepu
2016-04-21
Existing color sampling based alpha matting methods use the compositing equation to estimate alpha at a pixel from pairs of foreground (F) and background (B) samples. The quality of the matte depends on the selected (F,B) pairs. In this paper, the matting problem is reinterpreted as a sparse coding of pixel features, wherein the sum of the codes gives the estimate of the alpha matte from a set of unpaired F and B samples. A non-parametric probabilistic segmentation provides a certainty measure on the pixel belonging to foreground or background, based on which a dictionary is formed for use in sparse coding. By removing the restriction to conform to (F,B) pairs, this method allows for better alpha estimation from multiple F and B samples. The same framework is extended to videos, where the requirement of temporal coherence is handled effectively. Here, the dictionary is formed by samples from multiple frames. A multi-frame graph model, as opposed to a single image as for image matting, is proposed that can be solved efficiently in closed form. Quantitative and qualitative evaluations on a benchmark dataset are provided to show that the proposed method outperforms current state-of-the-art in image and video matting.
Alcoholism, Alpha Production, and Biofeedback
ERIC Educational Resources Information Center
Jones, Frances W.; Holmes, David S.
1976-01-01
Electroencephalograms of 20 alcoholics and 20 nonalcoholics were obtained. Data indicated that alcoholics produced less alpha than nonalcoholics. In one training condition subjects were given accurate biofeedback, whereas in the other condition subjects were given random (noncontingent) feedback. Accurate biofeedback did not result in greater…
Coexistence of {alpha}+{alpha}+n+n and {alpha}+t+t cluster structures in {sup 10}Be
Itagaki, N.; Ito, M.; Milin, M.; Hashimoto, T.; Ishiyama, H.; Miyatake, H.
2008-06-15
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.
A synopsis of collective alpha effects and implications for ITER
Sigmar, D.J.
1990-10-01
This paper discusses the following: Alpha Interaction with Toroidal Alfven Eigenmodes; Alpha Interaction with Ballooning Modes; Alpha Interaction with Fishbone Oscillations; and Implications for ITER.
NASA Astrophysics Data System (ADS)
Guttmann, Anthony J.
2016-10-01
Given the first 20-100 coefficients of a typical generating function of the type that arises in many problems of statistical mechanics or enumerative combinatorics, we show that the method of differential approximants performs surprisingly well in predicting (approximately) subsequent coefficients. These can then be used by the ratio method to obtain improved estimates of critical parameters. In favourable cases, given only the first 20 coefficients, the next 100 coefficients are predicted with useful accuracy. More surprisingly, this is also the case when the method of differential approximants does not do a useful job in estimating the critical parameters, such as those cases in which one has stretched exponential asymptotic behaviour. Nevertheless, the coefficients are predicted with surprising accuracy. As one consequence, significant computer time can be saved in enumeration problems where several runs would normally be made, modulo different primes, and the coefficients constructed from their values modulo different primes. Another is in the checking of newly calculated coefficients. We believe that this concept of approximate series extension opens up a whole new chapter in the method of series analysis.
Nica, N.; Hardy, J. C.; Iacob, V. E.; Balonek, C.; Trzhaskovskaya, M. B.
2008-03-15
Recently we measured the ratio of K-shell internal conversion coefficients, {alpha}{sub K}, for the 127.5-keV E3 transition in {sup 134}Cs and the 661.7-keV M4 transition in {sup 137}Ba. We here report a measurement of the 165.9-keV M1 transition in {sup 139}La, based on which we convert our earlier ratio measurement into individual {alpha}{sub K} values for the transitions in {sup 134}Cs and {sup 137}Ba. These results continue to confirm the Dirac-Fock calculations of internal conversion coefficients that incorporate the atomic K-shell vacancy.
What Causes Alpha-1 Antitrypsin Deficiency?
... Causes Alpha-1 Antitrypsin Deficiency? Alpha-1 antitrypsin (AAT) deficiency is an inherited disease. "Inherited" means it's ... parents to children through genes. Children who have AAT deficiency inherit two faulty AAT genes, one from ...
How Is Alpha-1 Antitrypsin Deficiency Treated?
... Alpha-1 Antitrypsin Deficiency Treated? Alpha-1 antitrypsin (AAT) deficiency has no cure, but its related lung ... pulmonary disease). If you have symptoms related to AAT deficiency, your doctor may recommend: Medicines called inhaled ...
Measurement of the iodine partition coefficient
Furrer, M.; Cripps, R.C.; Gubler, R.
1985-08-01
The hydrolysis of iodine is complicated because it involves a number of species that differ considerably in their individual volatilities. Large uncertainties exist in the thermodynamic data of some of the iodine species, especially at temperatures above 25C. Because of this, an experiment was undertaken to measure the partition coefficient under varying physical and chemical conditions. Measurements of P were made for a temperature range of 21 to 113C under well-defined conditions (liquid molar concentration, pH, and redox potential) for inorganic iodine. The experimental results are interpreted with the aid of an analytical model and published thermodynamic data. A good agreement between calculated and measured values was found. The experimental setup allows the determination of very high partition coefficients up to a value of 2.0 X 10W. This is demonstrated by adding cesium-iodide to the fuel pool water of a boiling water reactor.
Activity coefficient of aqueous sodium bicarbonate
Pitzer, Kenneth S.; Peiper, J. Christopher
1980-09-01
The determination of the activity coefficient and related properties of sodium bicarbonate presents special problems because of the appreciable vapor pressure of CO_{2} above such solutions. With the development of reliable equations for the thermodynamic properties of mixed electrolytes, it is possible to determine the parameters for NaHCO_{3} from cell measurements or NaCl-NaHCO_{3} mixtures. Literature data are analyzed to illustrate the method and provide interim values, hoever it is noted that further measurements over a wider range of concentrations would yield more definitive results. Lastly, an estimate is also given for the activity coefficient of KHCO_{3}.
Electron-Ion Recombination Rate Coefficient Measurements in a Flowing Afterglow Plasma
NASA Technical Reports Server (NTRS)
Gougousi, Theodosia; Golde, Michael F.; Johnsen, Rainer
1996-01-01
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.
The ultraviolet spectra of Alpha Aquilae and Alpha Canis Minoris
NASA Technical Reports Server (NTRS)
Morton, D. C.; Bruzual A., G.; Kurucz, R. L.; Spinrad, H.
1977-01-01
Scans of Alpha Aql (A7 IV, V) and Alpha CMi (F5 IV-V) obtained with the Copernicus satellite spectrometer over the wavelength range from 2100 to 3200 A are presented along with a spectrum of the integrated solar disk over the same range procured during a calibrated rocket flight. About 1500 fairly strong absorption lines in the Alpha CMi spectrum between 2400 and 2961 A are identified by comparison with a solar atlas and by using a theoretical spectrum synthesized from a blanketed LTE model with an effective temperature of 6500 K and a surface gravity of 10,000 cm/sec per sec. The Mg II resonance doublet at 2795.528 and 2802.704 A is found to be present in all three stars together with a discontinuity at 2635 A due to Fe II, Fe I, Cr I, and Mn II. It is concluded that the Mg II resonance lines and the 2635-A continuum break would be the best spectral features for estimating the redshift of a galaxy observed at low resolution provided the redshift is not less than about 0.75.
Numerical Integral of Resistance Coefficients in Diffusion
NASA Astrophysics Data System (ADS)
Zhang, Q. S.
2017-01-01
The resistance coefficients in the screened Coulomb potential of stellar plasma are evaluated to high accuracy. I have analyzed the possible singularities in the integral of scattering angle. There are possible singularities in the case of an attractive potential. This may result in a problem for the numerical integral. In order to avoid the problem, I have used a proper scheme, e.g., splitting into many subintervals where the width of each subinterval is determined by the variation of the integrand, to calculate the scattering angle. The collision integrals are calculated by using Romberg’s method, therefore the accuracy is high (i.e., ∼10‑12). The results of collision integrals and their derivatives for ‑7 ≤ ψ ≤ 5 are listed. By using Hermite polynomial interpolation from those data, the collision integrals can be obtained with an accuracy of 10‑10. For very weakly coupled plasma (ψ ≥ 4.5), analytical fittings for collision integrals are available with an accuracy of 10‑11. I have compared the final results of resistance coefficients with other works and found that, for a repulsive potential, the results are basically the same as others’ for an attractive potential, the results in cases of intermediate and strong coupling show significant differences. The resulting resistance coefficients are tested in the solar model. Comparing with the widely used models of Cox et al. and Thoul et al., the resistance coefficients in the screened Coulomb potential lead to a slightly weaker effect in the solar model, which is contrary to the expectation of attempts to solve the solar abundance problem.
Quenching of spontaneous emission coefficients in plasmas
Chung, Y.; Lemaire, P.; Suckewer, S.
1987-09-01
We have observed changing Einstein coefficients of spontaneous emission as a function of electron density in CO/sub 2/ laser-produced plasmas. These measurements are based on the intensity branching ratio of CIV lines 5801 to 5812 A and 312.41 to 312.46 A which share a common upper level. Similar observations for CIII lines are also discussed. 12 refs., 3 figs.
Correlation and prediction of gaseous diffusion coefficients.
NASA Technical Reports Server (NTRS)
Marrero, T. R.; Mason, E. A.
1973-01-01
A new correlation method for binary gaseous diffusion coefficients from very low temperatures to 10,000 K is proposed based on an extended principle of corresponding states, and having greater range and accuracy than previous correlations. There are two correlation parameters that are related to other physical quantities and that are predictable in the absence of diffusion measurements. Quantum effects and composition dependence are included, but high-pressure effects are not. The results are directly applicable to multicomponent mixtures.
Negative Temperature Coefficient in Chemical Reactions
NASA Astrophysics Data System (ADS)
Leenson, I. A.; Sergeev, Gleb B.
1984-05-01
A systematic analysis of reactions whose rate decreases with increase of temperature is presented. The possibility of a negative temperature coefficient in the elementary reactions is examined from the standpoint of the transition state theory and of collision theory. The mechanisms of complex reactions in which the temperature dependence of the rate is anomalous are discussed, and possible reasons for the anomaly are examined. The bibliography contains 175 references.
Absorption Coefficient of Alkaline Earth Halides.
1980-04-01
levels . As a natural consequence, the magnitude of the absorption coefficient is the key parameter in selecting laser window materials. Over the past...of as can be achieved through improved crystal growing techniques and surface polishing. 2.5. Urbach’s Rule A central question for the development of...high absorption levels , inaccuracies progressively increasing with decreasing absorption level , a natural consequence of decreasing in instrumental
Gasoline-Water Distribution Coefficients of Xylidines
1943-06-01
sample calculated. The extinction (absorption) of light is related to the concentration of the absorbing group by the Beer - Lambert law. It was neceaaar...the use of a Beckman quartz spectrophotometer . Data obtained 1dth the spectzrograph were checzed with the spectrophotom- eter and were reproducible to...within 5 percent of the value of the distribution coefficient given, The use of the spectrophotometer greatly enhanced the speed with which the
Edge Diffraction Coefficients around Critical Rays
NASA Astrophysics Data System (ADS)
Fradkin, L.; Harmer, M.; Darmon, M.
2014-04-01
The classical GTD (Geometrical Theory of Diffraction) gives a recipe, based on high-frequency asymptotics, for calculating edge diffraction coefficients in the geometrical regions where only diffracted waves propagate. The Uniform GTD extends this recipe to transition zones between irradiated and silent regions, known as penumbra. For many industrial materials, e.g. steels, and frequencies utlized in industrial ultrasonic transducers, that is, around 5 MHz, asymptotics suggested for description of geometrical regions supporting the head waves or transition regions surrounding their boundaries, known as critical rays, prove unsatisfactory. We present a numerical extension of GTD, which is based on a regularized, variable step Simpson's method for evaluating the edge diffraction coefficients in the regions of interference between head waves, diffracted waves and/or reflected waves. In mathematical terms, these are the regions of coalescence of three critical points - a branch point, stationary point and/or pole, respectively. We show that away from the shadow boundaries, near the critical rays the GTD still produces correct values of the edge diffraction coefficients.
Roughness coefficients for stream channels in Arizona
Aldridge, B.N.; Garrett, J.M.
1973-01-01
n in which V = mean cross-sectional velocity of flow, in feet per second; R = hydraulic radius at a cross section, which is the cross-sectional area divided by the wetter perimeter, in feet; Se = energy slope; and n = coefficient of roughness. Many research studies have been made to determine "n" values for open-channel flow (Carter and others, 1963). Guidelines for selecting coefficient of roughness for stream channels are given in most of the literature of stream-channel hydraulics, but few of the data relate directly to streams of Arizona, The U.S> Geological Survey, at the request of the Arizona Highway Department, assembled the color photographs and tables of the Manning "n" values in this report to aid highway engineers in the selection of roughness coefficients for Arizona streams. Most of the photographs show channel reaches for which values of "n" have been assigned by experienced Survey personnel; a few photographs are included for reaches where "n" values have been verified. Verified "n" values are computed from a known discharge and measured channel geometry. Selected photographs of stream channels for which "n" values have been verified are included in U.S. Geological Survey Water-Supply Paper 1849 (Barnes, 1967); stereoscopic slides of Barnes' (1967) photographs and additional photographs can be inspected at U.S> Geological Survey offices in: 2555 E. First Street, Tucson; and 5017 Federal Building, 230 N. First Avenue, Phoenix.
Determining the Temperature Coefficient of Reference Resistors
NASA Astrophysics Data System (ADS)
Bojkovski, J.; Batagelj, V.; Žužek, V.
2017-04-01
The influence of temperature on electrical resistance of standard resistors is presented within this paper. Electrical resistance is like any other quantity temperature dependent. This dependence is specified with the temperature coefficient, which gives the relative change of resistance with temperature. The level of resistance change is not linear as it changes with temperature, and therefore the coefficient is temperature dependent as well. At a certain temperature, its value is equal to zero—the stationary point. Use of the standard resistor at this exact temperature or in a narrow interval around it greatly reduces the influence of temperature on electrical resistance, even if the thermal conditions are not optimal. Measurements of temperature coefficient were taken on a group of standard resistors of the same type in a wide temperature range, and the temperature of the stationary point was determined. Measurements were taken by placing the resistors in an oil bath and changing its set point temperature from 18°C to 38°C. Electrical resistance of each resistor was measured using a resistance bridge, which had its reference resistor placed in a separate thermal enclosure at a constant temperature.
Drag coefficients for winter Antarctic pack ice
NASA Technical Reports Server (NTRS)
Wamser, Christian; Martinson, Douglas G.
1993-01-01
Air-ice and ice-water drag coefficients referenced to 10-m-height winds for winter Antarctic pack ice based on measurements made from R/V Polarstern during the Winter Weddell Sea Project, 1986 (WWSP-86), and from R/V Akademik Fedorov during the Winter Weddell Gyre Study, 1989 (WWGS-89), are presented. The optimal values of the air-ice drag coefficients, made from turbulent flux measurements, are (1.79 +/- 0.06) x 10 exp -3 for WWSP-86 and (1.45 +/- 0.09) x 10 exp -3 for WWGS-89. A single ice-water drag coefficient for both WWSP-86 and WWGS-89, estimated from periods of ice drift throught to represent free-drift conditions, is (1.13 +/- 0.26) x 10 exp -3, and the ice-water turning angle is 18 +/- 18 deg. It is suggested that for a typical Antarctic winter pack ice cover, the ice cover reduces the momentum flux from the atmosphere to the ocean by about 33 percent.
Discharge Coefficients for Axisymmetric Supersonic Nozzles
NASA Technical Reports Server (NTRS)
Ahmad, Rashid A.; McCool, A. A. (Technical Monitor)
2000-01-01
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.
Field verification of the wind tunnel coefficients
NASA Technical Reports Server (NTRS)
Gawronski, W. K.; Mellstrom, J. A.
1994-01-01
Accurate information about wind action on antennas is required for reliable prediction of antenna pointing errors in windy weather and for the design of an antenna controller with wind disturbance rejection properties. The wind tunnel data obtained 3 years ago using a scaled antenna model serves as an antenna industry standard, frequently used for the first purpose. The accuracy of the wind tunnel data has often been challenged, since they have not yet been tested in a field environment (full-aized antenna, real wind, actual terrain, etc.). The purpose of this investigation was to obtain selected field measurements and compare them with the available wind tunnel data. For this purpose, wind steady-state torques of the DSS-13 antenna were measured, and dimensionless wind torque coefficients were obtained for a variety of yaw and elevation angles. The results showed that the differences between the wind tunnel torque coefficients and the field torque coefficients were less than 10 percent of their values. The wind-gusting action on the antenna was characterized by the power spectra of the antenna encoder and the antenna torques. The spectra showed that wind gusting primarily affects the antenna principal modes.
Diffusion coefficients in gravel under unsaturated conditions
Conca, J.L.; Wright, J. )
1990-05-01
Diffusion coefficients were experimentally determined in unsaturated gravel to evaluate the effectiveness of gravel as a diffusion barrier to ionic transport in the vadose zone. Water contents were fixed by use of an ultracentrifuge with an ultralow constant rate flow pump supplying solution to the sample via a rotating seal. Once the gravel was at hydraulic steady state, the electrical conductivity was measured, and the diffusion coefficient calculated using the Nernst-Einstein equation. Diffusion coefficient values for potassium ion (D{sub e}) in four types of angular gravel ranged from 1.7 {times} 10{sup {minus}11} m{sup 2}/s (1.7 {times} 10{sup {minus}7} cm{sup 2}/s) for a 6.3-9.5 mm angular granitic gravel at a volumetric water content of 5.5% to 2.2 {times} 10{sup {minus}14} m{sup 2}/s (2.2 {times} 10{sup {minus}10} cm{sup 2}/s) in a 4.0-6.3 mm quartzite gravel at a volumetric water content of 0.47%. Variations in D{sub e} values resulted primarily from differences in water content which depends on gravel type and particle size.
Recent Results on the CKM Angle Alpha
Mihalyi, A.; /Wisconsin U., Madison
2005-10-18
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).
Genetics Home Reference: alpha-mannosidosis
... infantile form Orphanet: Alpha-mannosidosis The MPS Society (UK): Guide to Alpha-Mannosidosis (PDF) Patient Support and ... Organization for Rare Disorders (NORD) The MPS Society (UK) GeneReviews (1 link) Alpha-Mannosidosis ClinicalTrials.gov (1 ...
Effectiveness of Alpha Biofeedback Therapy: Negative Results.
ERIC Educational Resources Information Center
Watson, Charles G.; Herder, Joseph
1980-01-01
Assessed the utility of alpha biofeedback training in the treatment of patients (N=66). Biofeedback and placebo biofeedback groups were given alpha or mock-alpha training sessions. Improvement on 54 variables was compared to that of no-treatment controls. Only a chance number of significant changes appeared among the groups. (Author)
Sísa, Miroslav; Vilaplana-Polo, Marc; Ballesteros, Carme Brosa; Kohout, Ladislav
2007-10-01
In general, the structural requirements postulated for a high brassinolide activity are: 2alpha,3alpha-diol, 6-ketone or better 7-oxalactone in B-ring, A/B trans fused ring junction, a cis C-22,C-23-diol preferentially with RR configurations, and a C-24 methyl or ethyl substituent [Takatsuto S, Yazawa N, Ikekawa N, Takematsu T, Takeuchi Y, Koguchi M. Structure-activity relationship of brassinosteroids. Phytochemistry 1983;22:2437-41; Thompson MJ, Meudt WJ, Mandava NB, Dutky SR, Lusby WR, Spaulding DW. Synthesis of brassinosteroids and relationship of structure to plant growth-promoting effects. Steroids 1982;39:89-105]. We found that the 3alpha,4alpha-diols 4, 6 and 8 are more active than the 2alpha,3alpha-diols 3, 5 and 7 [Sísa M, Budesínský M, Kohout L. Synthesis of 7a-homo and 7a,7b-dihomo-5alpha-cholestane analogues of brassinolide. Collect Czech Chem Commun 2003;68:2171-89]. This fact is in strong contrast with the structure requirements mentioned above. Our hypothesis suggests that the lower activity of 2alpha,3alpha-diols and/or the higher activity of 3alpha,4alpha-diols could be explained by twisting and distortion of the molecule due to the seven- or eight-membered B-ring and also by the position of a carbonyl group relative to the A-ring diol. 3D-SAR computer methodologies as alignments and overlaps of GRID maps and 3D-QSAR analysis GRID-GOLPE (CoMFA-like) were used as an effort to explain the higher bioactivity of 3alpha,4alpha-diols 4, 6 and 8 in comparison with the 2alpha,3alpha-diols 3, 5 and 7 of B-ring enlarged brassinosteroids.
Voglibose: An Alpha Glucosidase Inhibitor
Dabhi, Ajay S.; Bhatt, Nikita R.; Shah, Mohit J.
2013-01-01
Diabetes Mellitus (DM) is a morbid disease worldwide, with increasing incidence as time passes. It has macro-vascular and micro-vascular complications. The main cause of these complications is poorly controlled postprandial hyperglycaemia. Alpha glucosidase inhibitors, namely acarbose, voglibose and miglitol, are available for therapy. Voglibose is well tolerated and effective in comparable doses among these drugs. This article highlights the important features of voglibose. PMID:24551718
Liebhaber, S A; Kan, Y W
1981-08-01
The alpha-globin polypeptide is encoded by two adjacent genes, alpha 1 and alpha 2. In the normal diploid state (alpha alpha/alpha alpha) all four alpha-globin genes are expressed. Loss or dysfunction of one or more of these genes leads to deficient alpha-globin production and results in alpha-thalassemia. We present a technique to differentially assess the steady-state levels of the alpha 1- and alpha-2-globin messenger RNA (mRNA) transcripts and thus delineate the relative level of expression of the two alpha-globin loci in a variety of alpha-thalassemia states. Only alpha 1 mRNA was produced in the alpha-thalassemia-2 haplotype (-alpha) (one of the two alpha-globin genes deleted from chromosome 16). This confirms previous gene mapping data which demonstrate deletion of the alpha 2 gene. The triple alpha-globin gene haplotype (alpha alpha alpha) is the reciprocal of the alpha-thalassemia-2 haplotype and thus contains an extra alpha 2-globin gene. RNA from this haplotype contained a greater than normal level of alpha 2-relative to alpha 1-globin mRNA. This data implies that the extra alpha 2 gene in the triple alpha-globin haplotype is functional. We detected a relative instability of the alpha 2-globin mRNA encoding the alpha-globin structural mutant Constant Spring. This instability may contribute to the low level of expression of the alpha-Constant Spring protein. In a Chinese patient with nondeletion hemoglobin-H disease (- -/alpha alpha T) (both alpha-globin genes are present but not fully functional) a normal ratio was maintained between the levels of alpha 1- and alpha 2-globin mRNA, implying that mRNA production from both alpha-globin genes is suppressed in a balanced manner. These observations extended previous findings concerning the structural rearrangements in the deletion types of alpha-thalassemia and the pathophysiology of two nondeletion variants.
Une, M; Inoue, A; Hoshita, T
1996-11-01
Varanic acid (3 alpha, 7 alpha, 12 alpha, 24-tetrahydroxy-5 beta-cholestanoic acid; 24-OH-THCA) is almost the sole component of bile acids in the bile of Bombina orientalis. To examine in the mechanism of the formation of 24-OH-THCA, radiolabeled (25R)- and (25S)-3 alpha, 7 alpha, 12 alpha-trihdroxy-5 beta-cholestanoic acids [(25R)- and (25S)-THCA] and (24E)-3 alpha, 7 alpha, 12 alpha-trihdroxy-5 beta-cholest-24-enoic acid (delta 24-THCA) were administered intraperitoneally to B. orientalis, gallbladder bile was collected after 24 h, and bile acids were subsequently extracted. Then the bile acids were analyzed by means of radio thin-layer chromatography and radio high-performance liquid chromatography after conversion to p-bromophenacyl ester derivatives. Although delta 24-THCA was not converted to 24-OH-THCA, (25R)-THCA and (25S)-THCA were transformed to (24R,25R)-24-OH-THCA and (24R,25S)-24-OH-THCA, respectively. These results strongly suggest that 24-OH-THCA was transformed via direct hydroxylation of the saturated side chain of THCA, not via hydration to an alpha, beta-unsaturated acid, delta 24-THCA, in B. orientalis.
Alpha voltaic batteries and methods thereof
NASA Technical Reports Server (NTRS)
Raffaelle, Ryne P. (Inventor); Jenkins, Phillip (Inventor); Wilt, David (Inventor); Scheiman, David (Inventor); Chubb, Donald (Inventor); Castro, Stephanie (Inventor)
2011-01-01
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.
THE LYMAN ALPHA REFERENCE SAMPLE: EXTENDED LYMAN ALPHA HALOS PRODUCED AT LOW DUST CONTENT
Hayes, Matthew; Oestlin, Goeran; Duval, Florent; Guaita, Lucia; Melinder, Jens; Sandberg, Andreas; Schaerer, Daniel; Verhamme, Anne; Orlitova, Ivana; Mas-Hesse, J. Miguel; Oti-Floranes, Hector; Adamo, Angela; Atek, Hakim; Cannon, John M.; Herenz, E. Christian; Kunth, Daniel; Laursen, Peter
2013-03-10
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.
Ikeda, Saiko; Tohyama, Tomoko; Yoshimura, Hiroyuki; Hamamura, Kimio; Abe, Kouichi; Yamashita, Kanae
2003-02-01
We previously showed that alpha- and gamma-tocotrienols accumulate in adipose tissue and skin but not in plasma or other tissues of rats fed a tocotrienol-rich fraction extracted from palm oil containing alpha-tocopherol and alpha- and gamma-tocotrienols. To clarify the nature of tocotrienol metabolism, we studied the distribution of alpha- or gamma-tocotrienol in rats fed alpha- or gamma-tocotrienol without alpha-tocopherol, and the effect of alpha-tocopherol on their distribution. Wistar rats (4-wk-old) were fed a diet with 50 mg alpha-tocotrienol/kg alone or with 50 mg alpha-tocopherol/kg in expt. 1, and a diet with 50 mg gamma-tocotrienol/kg alone or with 50 mg alpha-tocopherol/kg in expt. 2, for 8 wk. alpha-Tocotrienol was detected in various tissues and plasma of the rats fed alpha-tocotrienol alone, and the alpha-tocotrienol concentrations in those tissues and plasma decreased (P < 0.05) by the dietary alpha-tocopherol in the rats fed alpha-tocotrienol with alpha-tocopherol. However, gamma-tocotrienol preferentially accumulated in the adipose tissue and skin of the rats fed gamma-tocotrienol alone, and the dietary alpha-tocopherol failed either to decrease (P >/= 0.05) gamma-tocotrienol concentrations in the adipose tissue and skin or to increase (P >/= 0.05) in the urinary excretion of 2,7,8-trimethyl-2(2'-carboxymethyl)-6-hydroxycroman, a metabolite of gamma-tocotrienol, in the rats fed gamma-tocotrienol with alpha-tocopherol. These data suggest that alpha-tocopherol enhances the alpha-tocotrienol metabolism but not the gamma-tocotrienol metabolism in rats.
A Method for Maximizing Split-Half Reliability Coefficients
ERIC Educational Resources Information Center
Callender, John C.; Osburn, H. G.
1977-01-01
An efficient algorithm for maximizing split-half reliability coefficients is described. Coefficients derived by the algorithm were found to be generally larger than odd-even split-half coefficients or other internal consistency measures and nearly as large as the largest split half coefficients. MSPLIT, Odd-Even, and Kuder-Richardson-20…
PPAR-alpha in cutaneous inflammation
Schmuth, Matthias
2011-01-01
Peroxisome proliferator-activated receptor (PPAR)-alpha is a fatty acid activated transcription factors that belongs to the nuclear hormone receptor family. Primarily PPAR-alpha serves as a lipid sensor. While PPAR-alpha controls enzymes from the lipid and glucose metabolism in the liver, heart and muscles, PPAR-alpha is also involved in skin homeostasis. PPAR-alpha controls keratinocyte proliferation/differentiation, contributes to wound healing and regulates skin inflammation. PPAR-alpha activation exerts anti-inflammatory effects in various skin conditions such as irritant and allergic contact dermatitis, atopic dermatitis and UV-induced erythema, rendering investigations into the functions of PPAR-alpha necessary to provide better understandings to treat many inflammatory skin disorders. PMID:21519405
8alpha-hydroxyflavinmononucleotide and related compounds.
Zhilina, T A; Berezoyski, V M
1977-01-01
2', 3', 4'-Triacetyl-FMN has been transformed by selective radical bromination into 2', 3', 4'-triacetyl-8alpha-bromo-FMN, and the following hydrolysis of the latter has afforded 8alpha-hydroxy-FMN. The presence of the hydroxy group in the 8alpha position of 8alpha-hydroxy-FMN is confirmed by its acetylation into 2', 3'-diacetyl-8alpha-acetoxyriboflavin-4', 5'-cyclophosphate. The absorption spectra of the synthesized compounds have shown the reduction of the extinction ratios of the first and second absorption maxima in comparison with the extinction of the same maxima for 8alpha-hydroxyriboflavin. Unlike FMN, fluorescence quenching for 8alpha-hydroxy-FMN has been found.
Physiologic and prognostic significance of "alpha coma".
Iragui, V J; McCutchen, C B
1983-01-01
A patient with posthypoxic "alpha coma" is described whose EEGs were recorded before coma, within two hours following the onset of coma and after recovery. The differences observed between the alpha activity during coma and that seen before and after suggest that the alpha activity during coma and the physiologic alpha rhythm are different phenomena. This case, as well as others reported, also suggests that "alpha coma" resolving in the first 24 hours following hypoxia may have a better prognosis than "alpha coma" detected after the first day, and stresses the need for EEG monitoring begun in the immediate period following hypoxia in order to assess accurately the prognostic significance of this EEG pattern in the early stages of postanoxic encephalopathy. The aetiology of "alpha coma" also affects outcome. The survival rate appears higher in patients with respiratory arrest than in those with combined cardiopulmonary arrest. PMID:6886700
Transport coefficients of He(+) ions in helium.
Viehland, Larry A; Johnsen, Rainer; Gray, Benjamin R; Wright, Timothy G
2016-02-21
This paper demonstrates that the transport coefficients of (4)He(+) in (4)He can be calculated over wide ranges of E/N, the ratio of the electrostatic field strength to the gas number density, with the same level of precision as can be obtained experimentally if sufficiently accurate potential energy curves are available for the X(2)Σu (+) and A(2)Σg (+) states and one takes into account resonant charge transfer. We start by computing new potential energy curves for these states and testing their accuracy by calculating spectroscopic values for the separate states. It is established that the potentials obtained by extrapolation of results from d-aug-cc-pVXZ (X = 6, 7) basis sets using the CASSCF+MRCISD approach are each in exceptionally close agreement with the best potentials available and with experiment. The potentials are then used in a new computer program to determine the semi-classical phase shifts and the transport cross sections, and from these the gaseous ion transport coefficients are determined. In addition, new experimental values are reported for the mobilities of (4)He(+) in (4)He at 298.7 K, as a function of E/N, where careful consideration is given to minimizing various sources of uncertainty. Comparison with previously measured values establishes that only one set of previous data is reliable. Finally, the experimental and theoretical ion transport coefficients are shown to be in very good to excellent agreement, once corrections are applied to account for quantum-mechanical effects.
Conditional Reliability Coefficients for Test Scores.
Nicewander, W Alan
2017-04-06
The most widely used, general index of measurement precision for psychological and educational test scores is the reliability coefficient-a ratio of true variance for a test score to the true-plus-error variance of the score. In item response theory (IRT) models for test scores, the information function is the central, conditional index of measurement precision. In this inquiry, conditional reliability coefficients for a variety of score types are derived as simple transformations of information functions. It is shown, for example, that the conditional reliability coefficient for an ordinary, number-correct score, X, is equal to, ρ(X,X'|θ)=I(X,θ)/[I(X,θ)+1] Where: θ is a latent variable measured by an observed test score, X; p(X, X'|θ) is the conditional reliability of X at a fixed value of θ; and I(X, θ) is the score information function. This is a surprisingly simple relationship between the 2, basic indices of measurement precision from IRT and classical test theory (CTT). This relationship holds for item scores as well as test scores based on sums of item scores-and it holds for dichotomous as well as polytomous items, or a mix of both item types. Also, conditional reliabilities are derived for computerized adaptive test scores, and for θ-estimates used as alternatives to number correct scores. These conditional reliabilities are all related to information in a manner similar-or-identical to the 1 given above for the number-correct (NC) score. (PsycINFO Database Record
Elastic-Stiffness Coefficients of Titanium Diboride
Ledbetter, Hassel; Tanaka, Takaho
2009-01-01
Using resonance ultrasound spectroscopy, we measured the monocrystal elastic-stiffness coefficients, the Voigt Cij, of TiB2. With hexagonal symmetry, TiB2 exhibits five independent Cij: C11, C33, C44, C12, C13. Using Voigt-Reuss-Hill averaging, we converted these monocrystal values to quasiisotropic (polycrystal) elastic stiffnesses. Briefly, we comment on effects of voids. From the Cij, we calculated the Debye characteristic temperature, the Grüneisen parameter, and various sound velocities. Our study resolves the enormous differences between two previous reports of TiB2’s Cij. PMID:27504232
Onsager coefficients for systems with periodic potentials
NASA Astrophysics Data System (ADS)
Rosas, Alexandre; Van den Broeck, Christian; Lindenberg, Katja
2016-11-01
We carry out the thermodynamic analysis of a Markovian stochastic engine, driven by a spatially and temporally periodic modulation in a d -dimensional space. We derive the analytic expressions for the Onsager coefficients characterizing the linear response regime for the isothermal transfer of one type of work (a driver) to another (a load), mediated by a stochastic time-periodic machine. As an illustration, we obtain the explicit results for a Markovian kangaroo process coupling two orthogonal directions and find extremely good agreement with numerical simulations. In addition, we obtain and discuss expressions for the entropy production, power, and efficiency for the kangaroo process.
Fresnel coefficients in materials with magnetic monopoles.
Costa-Quintana, J; López-Aguilar, F
2011-02-14
Recent experiments have found entities in crystals whose behavior is equivalent to magnetic monopoles. In this paper, we explain some optical properties based on the reformulated "Maxwell" equations in material media in which there are equivalent magnetic charges. We calculate the coefficients of reflection and transmission of an electromagnetic wave in a plane interface between the vacuum and a medium with magnetic charges. These results can give a more extended vision of the properties of the materials with magnetic monopoles, since the phase and the amplitudes of the reflected and transmitted waves, differ with and without these magnetic entities.
Surface area coefficients for airship envelopes
NASA Technical Reports Server (NTRS)
Diehl, W S
1922-01-01
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.
Random Matrices and Lyapunov Coefficients Regularity
NASA Astrophysics Data System (ADS)
Gallavotti, Giovanni
2017-02-01
Analyticity and other properties of the largest or smallest Lyapunov exponent of a product of real matrices with a "cone property" are studied as functions of the matrices entries, as long as they vary without destroying the cone property. The result is applied to stability directions, Lyapunov coefficients and Lyapunov exponents of a class of products of random matrices and to dynamical systems. The results are not new and the method is the main point of this work: it is is based on the classical theory of the Mayer series in Statistical Mechanics of rarefied gases.
Effective distribution coefficient in magnetic Czochralski growth
NASA Astrophysics Data System (ADS)
Hurle, D. T. J.; Series, R. W.
1985-10-01
The analysis by Burton, Prim and Slichter (1953) of the dependence of the effective distribution coefficient (keff) on the growth and crystal rotation rates in Czochralski growth is extended to include the effect of an imposed steady axial magnetic field. The theory is based on the analysis of the hydromagnetic flow at a rotating disk due to Kakutani (1962). It is shown that keff approaches unity as the field increases. The likely effects of this on the growth of silicon and gallium arsenide are discussed.
Experimental rotordynamic coefficient results for honeycomb seals
NASA Technical Reports Server (NTRS)
Elrod, David A.; Childs, Dara W.
1988-01-01
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.
Peltier coefficient measurement in a thermoelectric module
NASA Astrophysics Data System (ADS)
Garrido, Javier; Casanovas, Alejandro; María Chimeno, José
2013-09-01
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.
Gauge Invariance of Thermal Transport Coefficients
NASA Astrophysics Data System (ADS)
Ercole, Loris; Marcolongo, Aris; Umari, Paolo; Baroni, Stefano
2016-10-01
Thermal transport coefficients are independent of the specific microscopic expression for the energy density and current from which they can be derived through the Green-Kubo formula. We discuss this independence in terms of a kind of gauge invariance resulting from energy conservation and extensivity, and demonstrate it numerically for a Lennard-Jones fluid, where different forms of the microscopic energy density lead to different time correlation functions for the heat flux, all of them, however, resulting in the same value for the thermal conductivity.
High-Resolution {alpha} and Electron Spectroscopy of {sup 249}{sub 98}Cf
Ahmad, I.; Greene, J. P.; Kondev, F. G.; Zhu, S.
2015-04-13
alpha-particle spectra of Cf-249 have been measured with a double-focusing magnetic spectrometer and with passivated implanted planar silicon (PIPS) detectors. The conversion-electron spectra of Cf-249 have been measured with a cooled Si(Li) detector and with a room-temperature PIPS detector. Precise energies of a groups in the decay of Cf-249 have been measured with respect to the known energy of Cf-250. In addition, alpha-electron, alpha-gamma, and gamma-gamma coincidence measurements were also performed to determine the spin-parity of the previously known 643.64-keV level. From electron intensities, conversion coefficients of transitions in the daughter Cm-245 have been determined. The measured L-3 conversion coefficients of the 333.4- and 388.2-keV transitions are found to be in agreement with the theoretical conversion coefficients for pure E1 multipolarity. On the other hand, the K, L-1 + L-2, M, and N conversion coefficients are approximately twice the theoretical values for pure E1 transitions. These measurements indicate anomalous E1 conversion coefficients for the 333.4- and 388.2-keV transitions, as has been pointed out in earlier measurements. The measured conversion coefficient of the 255.5-keV transition gives an M1 multipolarity for this transition which establishes a spin-parity of 7/2(-) and the 7/2(-)[743] single-particle assignment to the 643.64-keV level.
alpha-Tocopheryl phosphate – an active lipid mediator?
Technology Transfer Automated Retrieval System (TEKTRAN)
The vitamin E (alpha-tocopherol, alphaT) derivative, alpha-tocopheryl phosphate (alphaTP), is detectable in small amounts in plasma, tissues, and cultured cells. Studies done in vitro and in vivo suggest that alphaT can become phosphorylated and alphaTP dephosphorylated, suggesting the existence of ...
Is Hb A2 elevated in adults with sickle-alpha-thalassemia (beta(S)/beta(S); -alpha/-alpha)?
Ballas, S K; Gay, R N; Chehab, F F
1997-09-01
Thirteen patients with sickle cell anemia (SS) were found to have two alpha gene deletions with a presumptive genotype of beta(S)/beta(S); -alpha/-alpha. Hematological data showed that this group of patients had elevated Hb A2 level. In order to determine whether the elevation of Hb A2 is typical of SS with a two alpha gene deletion or is due to undiagnosed S-beta(O)-thalassemia with a two alpha gene deletion we looked for the presence or absence of beta(O)-thalassemia by molecular techniques. The latter included reverse dot-blot hybridization to rule out a beta-thalassemia mutation, digestion with CvnI endonuclease followed by Southern blotting and hybridization with a beta genomic probe, and, in selected patients, determination of the synthetic alpha/beta ratio. One of the 13 patients had S-beta(O)-thalassemia with a G-->A mutation at IVS-II-1 indicating that her genotype was beta(S)/beta(O) thalassemia; -alpha/-alpha. The remaining 12 patients were homozygous for the sickle gene, had relatively elevated Hb levels, increased Hb A2 values, and Hb F levels similar to those in patients with SS and four or three alpha genes. At the clinical level, the 12 patients with SS and a two alpha gene deletion had increased prevalence of avascular necrosis, retinopathy, and splenomegaly, but decreased prevalence of leg ulcers and cerebrovascular accidents. Together, the data indicate that SS with a two alpha gene deletion (beta(S)/beta(S); -alpha/-alpha) is a unique subset of patients with SS characterised by distinct hematological and clinical features.
An analytical model for calculating internal dose conversion coefficients for non-human biota.
Amato, Ernesto; Italiano, Antonio
2014-05-01
To assess the radiation burden of non-human living organisms, dose coefficients are available in the literature, precalculated by assuming an ellipsoidal shape of each organism. A previously developed analytical method was applied for the determination of absorbed fractions inside ellipsoidal volumes from alpha, beta, and gamma radiations to the calculation of dose conversion coefficients (DCCs) for 15 reference organisms, animals and plants, either terrestrial, amphibian, or aquatic, and six radionuclides ((14)C, (90)Sr, (60)Co, (137)Cs, (238)U, and (241)Am). The results were compared with the reference values reported in Publication 108 of the International Commission on Radiological Protection, in which a different calculation approach for DCCs was employed. The results demonstrate that the present analytical method, originally intended for applications in internal dosimetry of nuclear medicine therapy, gives consistent results for all the beta-, beta-gamma-, and alpha-emitting radionuclides tested in a wide range of organism masses, between 8 mg and 1.3 kg. The applicability of the method proposed can take advantage from its ease of implementation in an ordinary electronic spreadsheet, allowing to calculate, for virtually all possible radionuclide emission spectra, the DCCs for ellipsoidal models of non-human living organisms in the environment.
SDSS-II: Determination of shape and color parameter coefficients for SALT-II fit model
Dojcsak, L.; Marriner, J.; /Fermilab
2010-08-01
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.
The convergence coefficient across political systems.
Gallego, Maria; Schofield, Norman
2013-01-01
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.
Estimating biokinetic coefficients in the PACT™ system.
Shen, Zhiyao; Arbuckle, Wm Brian
2016-02-01
When powdered activated carbon (PAC) is continuously added to the aeration tank of an activated sludge reactor, the modification is called a PACT™ process (for powdered activated carbon treatment). The PAC provides many benefits, but complicates the determination of biological phenomena. Determination of bio-oxidation kinetics in a PACT system is a key to fully understanding enhanced biological mechanisms resulting from PAC addition. A model is developed to account for the main mechanisms involved in the PACT system -- adsorption, air stripping and bio-oxidation. The model enables the investigation of biokinetic information, including possible synergistic effects. Six parallel reactors were used to treat a synthetic waste; three activated sludge and three PACT. The PACT reactors provided significantly reduced effluent TOC (total organic carbon). Biokinetic coefficients were obtained from steady-state data using averaged reactor data and by using all data (22 points for each reactor). As expected, the PACT reactors resulted in a substantial reduction in the effluent concentration of non-biodegradable total organic carbon. The Monod equation's half-saturation coefficient (Ks) was reduced significantly in the PACT reactors, resulting in higher growth rates at lower concentrations. The maximum specific substrate utilization (qm) rate was also reduced about 25% using the averaged data and remained unchanged using all the data. The substrate utilization values are affected by errors in biomass determination and more research is needed to accurately determine biomass.
Hood entry coefficients of compound exhaust hoods.
Figueroa, Crescente E
2011-12-01
A traditional method for assessing the flow rate in ventilation systems is based on multiple readings of velocity or velocity pressure (VP) (usually 10 or 20 points) taken in ductwork sections located away from fittings (> seven × diameters of straight duct). This study seeks to eliminate the need for a multiple-point evaluation and replace it with a simplified method that requires only a single measurement of hood static pressure (SP(h)) taken at a more accessible location (< three × diameters of straight duct from the hood entry). The SP(h) method is widely used for the assessment of flow rate in simple hoods. However, industrial applications quite often use compound hoods that are regularly of the slot/plenum type. For these hoods, a "compound coefficient of entry" has not been published, which makes the use of the hood static pressure method unfeasible. This study proposes a model for the computation of a "compound coefficient of entry" and validates the use of this model to assess flow rate in two systems of well-defined geometry (multi-slotted/plenum and single-slotted/tapered or "fish-tail" types). When using a conservative value of the slot loss factor (1.78), the proposed model yielded an estimate of the volumetric flow rate within 10% of that provided by a more comprehensive method of assessment. The simplicity of the hood static pressure method makes it very desirable, even in the upper range of experimental error found in this study.
On Learning Cluster Coefficient of Private Networks
Wang, Yue; Wu, Xintao; Zhu, Jun; Xiang, Yang
2013-01-01
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 εi, 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
Coefficient adaptive triangulation for strongly anisotropic problems
D`Azevedo, E.F.; Romine, C.H.; Donato, J.M.
1996-01-01
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.
Full wave-field reflection coefficient inversion.
Dettmer, Jan; Dosso, Stan E; Holland, Charles W
2007-12-01
This paper develops a Bayesian inversion for recovering multilayer geoacoustic (velocity, density, attenuation) profiles from a full wave-field (spherical-wave) seabed reflection response. The reflection data originate from acoustic time series windowed for a single bottom interaction, which are processed to yield reflection coefficient data as a function of frequency and angle. Replica data for inversion are computed using a wave number-integration model to calculate the full complex acoustic pressure field, which is processed to produce a commensurate seabed response function. To address the high computational cost of calculating short range acoustic fields, the inversion algorithms are parallelized and frequency averaging is replaced by range averaging in the forward model. The posterior probability density is interpreted in terms of optimal parameter estimates, marginal distributions, and credibility intervals. Inversion results for the full wave-field seabed response are compared to those obtained using plane-wave reflection coefficients. A realistic synthetic study indicates that the plane-wave assumption can fail, producing erroneous results with misleading uncertainty bounds, whereas excellent results are obtained with the full-wave reflection inversion.
The Convergence Coefficient across Political Systems
Schofield, Norman
2013-01-01
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
On Varying-coefficient Independence Screening for High-dimensional Varying-coefficient Models.
Song, Rui; Yi, Feng; Zou, Hui
2014-01-01
Varying coefficient models have been widely used in longitudinal data analysis, nonlinear time series, survival analysis, and so on. They are natural non-parametric extensions of the classical linear models in many contexts, keeping good interpretability and allowing us to explore the dynamic nature of the model. Recently, penalized estimators have been used for fitting varying-coefficient models for high-dimensional data. In this paper, we propose a new computationally attractive algorithm called IVIS for fitting varying-coefficient models in ultra-high dimensions. The algorithm first fits a gSCAD penalized varying-coefficient model using a subset of covariates selected by a new varying-coefficient independence screening (VIS) technique. The sure screening property is established for VIS. The proposed algorithm then iterates between a greedy conditional VIS step and a gSCAD penalized fitting step. Simulation and a real data analysis demonstrate that IVIS has very competitive performance for moderate sample size and high dimension.
On Varying-coefficient Independence Screening for High-dimensional Varying-coefficient Models
Song, Rui; Yi, Feng; Zou, Hui
2014-01-01
Varying coefficient models have been widely used in longitudinal data analysis, nonlinear time series, survival analysis, and so on. They are natural non-parametric extensions of the classical linear models in many contexts, keeping good interpretability and allowing us to explore the dynamic nature of the model. Recently, penalized estimators have been used for fitting varying-coefficient models for high-dimensional data. In this paper, we propose a new computationally attractive algorithm called IVIS for fitting varying-coefficient models in ultra-high dimensions. The algorithm first fits a gSCAD penalized varying-coefficient model using a subset of covariates selected by a new varying-coefficient independence screening (VIS) technique. The sure screening property is established for VIS. The proposed algorithm then iterates between a greedy conditional VIS step and a gSCAD penalized fitting step. Simulation and a real data analysis demonstrate that IVIS has very competitive performance for moderate sample size and high dimension. PMID:25484548
NASA Astrophysics Data System (ADS)
Wang, Lihong; Jacques, Steven L.
1995-05-01
A simple and quick approach is used to measure the reduced scattering coefficient ( mu s `) of a semi-infinite turbid medium having a much smaller absorption coefficient than mu s`. A laser beam with an oblique angle of incidence to the medium causes the center of the diffuse reflectance that is several transport mean-free paths away from the incident point to shift away from the point of incidence by an amount Delta x. This amount is used to compute mu s` by mu s` = sin( alpha i)/(n Delta x), where n is the refractive index of the turbid medium divided by that of the incident medium and alpha i is the angle of incidence measured from the surface normal. For a turbid medium having an absorption coefficient comparable with mu s `, a revision to the above formula is made. This method is tested theoretically by Monte Carlo simulations and experimentally by a video reflectometer.
ERIC Educational Resources Information Center
Fife, Dustin A.; Mendoza, Jorge L.; Terry, Robert
2012-01-01
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…
Sun, Z T; Henson, C A
1991-02-01
Extracts of germinated barley (Hordeum vulgare L.) seeds of 41 different genotypes were analyzed for their activities of alpha-amylase, beta-amylase, alpha-glucosidase, and debranching enzyme and for their abilities to hydrolyze boiled soluble starch, nonboiled soluble starch, and starch granules extracted from barley seeds with water. Linear correlation analysis, used to quantitate the interactions between the seven parameters, revealed that boiled soluble starch was not a good substrate for predicting activities of enzymes functioning in in vivo starch hydrolysis as the extracts' abilities to hydrolyze boiled soluble starch was not correlated with their abilities to hydrolyze native starch granules. Activities of alpha-amylase and alpha-glucosidase were positively and significantly correlated with the seed extracts' abilities to hydrolyze all three starches. beta-Amylase was only significantly correlated with hydrolysis of boiled soluble starch. No significant correlations existed between debranching enzyme activity and hydrolysis of any of the three starches. Interactions between the four enzymes as they functioned together to hydrolyze the three types of starch were evaluated by path coefficient analysis. alpha-Amylase contributed to hydrolyses of all three starches primarily by its direct effect (noninteractive component). This direct contribution increased as the substrate progressed from the completely artificial boiled soluble starch, to the most physiologically significant substrate, native starch granules. alpha-Glucosidase contributed to the hydrolysis of boiled soluble starch primarily by its direct effect (noninteractive) yet contributed to starch granule hydrolysis primarily via its interaction with alpha-amylase (indirect effect). The contribution of beta-amylase to hydrolysis of boiled soluble starch was direct and it did not contribute significantly to hydrolysis of native starch granules.
Asher, O; Jensen, B S; Lupu-Meiri, M; Oron, Y; Fuchs, S
1998-04-17
The mongoose AChR alpha-subunit has been cloned and shown to be highly homologous to other AChR alpha-subunits, with only six differences in amino acid residues at positions that are conserved in animal species that bind alpha-bungarotoxin (alpha-BTX). Four of these six substitutions cluster in the ligand binding site, and one of them, Asn-187, forms a consensus N-glycosylation site. The mongoose glycosylated alpha-subunit has a higher apparent molecular mass than that of the rat glycosylated alpha-subunit, probably resulting from the additional glycosylation at Asn-187 of the mongoose subunit. The in vitro translated mongoose alpha-subunit, in a glycosylated or non-glycosylated form, does not bind alpha-BTX, indicating that lack of alpha-BTX binding can be achieved also in the absence of glycosylation.
Shepperson, N. B.
1984-01-01
Alpha 1 but not alpha 2-adrenoceptors mediate contractions of the cat nictitating membrane. The contractions of this tissue evoked by alpha 1-adrenoceptor agonists, but not those evoked by angiotensin II, are potentiated by pre-dosing with alpha 2-adrenoceptor agonists. This potentiation is reversed by the alpha 2-adrenoceptor antagonist, WY 26392. Pressor responses evoked by alpha 1-adrenoceptor agonists or angiotensin II were not affected by alpha 2-adrenoceptor agonists. Contractions of the nictitating membrane evoked by noradrenaline were reduced by pretreatment with WY 26392. These results suggest that in some tissues the role of alpha 2-adrenoceptors may be to modulate responses to alpha 1-adrenoceptors, rather than to evoke a discrete response themselves. PMID:6148985
Lymphatic transport of alpha-, gamma- and delta-tocotrienols and alpha-tocopherol in rats.
Ikeda, I; Imasato, Y; Sasaki, E; Sugano, M
1996-01-01
Lymphatic transport of alpha-, gamma- and delta-tocotrienols and alpha-tocopherol was measured in thoracic duct-cannulated rats. Animals were administered 3 ml of a test emulsion containing 200 mg sodium taurocholate, 50 mg fatty acid free-albumin, 200 mg fat and 100 mg of a mixture of tocotrienols and alpha-tocopherol (Exp. 1) or 10 mg of purified alpha-, gamma- or delta-tocotrienol or alpha-tocopherol (Exp. 2) through a gastric tube. Quantitative lymphatic recovery of oleic acid given as triolein was obtained in these experimental conditions. The 24-hours recovery of tocotrienols and alpha-tocopherol were 10-20% of the administered dose in Exp. 1. The recovery of alpha-tocotrienol was about 2-times higher than that of alpha-tocopherol, while that of gamma- and delta-tocotrienols was intermediate between these two alpha-forms. In Exp. 2, where these compounds were administered individually, the 24 hours recovery ranged from 22 to 37% of the administered dose. Again, the recovery of alpha-tocotrienol was significantly higher than that of the other tocotrienols and alpha-tocopherol, while that of gamma- and delta-tocotrienols and alpha-tocopherol was comparable. Thus, the results show the preferential absorption of alpha-tocotrienol compared to gamma- and delta-tocotrienols and alpha-tocopherol.
Mikheev, N.B.; Kamenskaya, A.N.; Auerman, L.N.; Kulyukhin, S.A.; Rumer, I.A.; Novichenko, V.L.
1987-11-01
The method of separation of californium, einsteinium, fermium, and certain lanthanides, based on the use of ammonium ..cap alpha..-hydroxyisobutyrate as the eluent, has been improved. The use of a 0.10-0.14 M solution of this reagent and columns (9 x 0.5 cm) filled with the resin Aminex SB with particle size 20-25 ..mu.., permitted the production of about 0.5 ..mu..g of einsteinium-253 from irradiated californium-252 with coefficient of purification of einsteinium from californium in two cycles of adsorption and elution of approx. 10/sup 10/. The coefficient of separation of californium and einsteinium is equal to 1.6 and that of einsteinium and fermium 1.9. The behavior of certain lanthanides in the separation of californium, einsteinium, and fermium using a 0.010 M solution of ammonium ..cap alpha..-hydroxyisobutyrate is discussed.
The Seebeck coefficient of monocrystalline α-SiC and polycrystalline β-SiC measured at 300-533 K
NASA Astrophysics Data System (ADS)
Abu-Ageel, N.; Aslam, M.; Ager, R.; Rimai, L.
2000-01-01
The temperature dependence of the Seebeck coefficient of polycrystalline icons/Journals/Common/beta" ALT="beta" ALIGN="TOP"/> -SiC films deposited on quartz substrates by laser ablation and of commercially available icons/Journals/Common/alpha" ALT="alpha" ALIGN="TOP"/> -SiC wafers is reported in a temperature range of 300-533 K for the first time. The Seebeck emf of icons/Journals/Common/alpha" ALT="alpha" ALIGN="TOP"/> -SiC substrates and icons/Journals/Common/beta" ALT="beta" ALIGN="TOP"/> -SiC samples ranges between -9 µV °C-1 and -108 µV °C-1 which is higher than that of commercial Pt thermocouples.
A new coefficient of concordance with applications to biosignal analysis
NASA Astrophysics Data System (ADS)
Xu, Weichao; Chen, Zhaoguo; Liu, Wenqing
2015-12-01
In this paper we propose a novel concordance coefficients called Order Statistics Concordance Coefficients based on order statistics and Pearson's Product Moment Correlation Coefficient. For comparison, we also construct other three similar index based on Average Pearson's Product Moment Correlation Coefficient, Kendall's Concordance Coefficients, Average Kendall's tau. We propose Multivariate Normal Model to estimate the correlation coefficient, Linear Model and Nonlinear Model to model the linear and nonlinear association between multichannel signals, And we also apply the concordance coefficients to biosignal analysis developed a new organizational index for quantifying organization of AF. Statistical evidences suggest that (a) Order Statistics Concordance Coefficients have better robust than other three index; (b) capable of distinguishing fibrillatory rhythms from nonfibrillatory rhythms, such as Atiral flutter; (c) can reflect the effectiveness of adenosine, a drug commonly used during electrophysiological procedures; and (d) perform better than other three concordance coefficients.
Targeted alpha therapy for cancer
NASA Astrophysics Data System (ADS)
Allen, Barry J.; Raja, Chand; Rizvi, Syed; Li, Yong; Tsui, Wendy; Zhang, David; Song, Emma; Qu, Chang Fa; Kearsley, John; Graham, Peter; Thompson, John
2004-08-01
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
Schindler, C; Grossmann, M; Dobrev, D; Francke, K; Ravens, U; Kirch, W
2003-03-01
Assessment of drug-induced venodilation by the dorsal hand vein compliance method requires stable constriction of the vein. This study was designed to investigate intra- and intersubject reproducibility of the venous preconstriction technique in response to phenylephrine and prostaglandin F2 alpha and to determine the influence of basal vein size. Twelve healthy male nonsmokers participated in a prospective cross-over study. Inter- and intrasubject variability was tested in response to phenylephrine and PGF2 alpha on different study days in the same hand vein. The dose of the respective constrictor causing approximately 80% constriction of the vein (ED80) was determined and infused for another 100 minutes. Actual vein size was measured every 5 minutes. Coefficient of variation and regression analyses were performed to analyze influence of vessel size on ED80 of the respective constrictor. Adjusted constriction levels were stable and well reproducible in all subjects. The intersubject coefficient of variation of ED80 ranged from 0.9% to 6.7% for phenylephrine and from 0.9% to 6.9% for PGF2 alpha. Whereas responses to phenylephrine were independent of basal vein diameter, there was a positive correlation between ED80 of PGF2 alpha and basal vein size. Thus, the hand vein compliance method is a suitable method to study dilatory responses in phenylephrine- or PGF2 alpha-constricted veins with considerable interindividual but small intraindividual variability. However, in such studies, phenylephrine appears to be a more reliable tool than PGF2 alpha.
Apparent diffusion coefficient normalization of normal liver
Zhu, Jie; Zhang, Jie; Gao, Jia-Yin; Li, Jin-Ning; Yang, Da-Wei; Chen, Min; Zhou, Cheng; Yang, Zheng-Han
2017-01-01
Abstract Apparent diffusion coefficient (ADC) measurement in diffusion-weighted imaging (DWI) has been reported to be a helpful biomarker for detection and characterization of lesion. In view of the importance of ADC measurement reproducibility, the aim of this study was to probe the variability of the healthy hepatic ADC values measured at 3 MR scanners from different vendors and with different field strengths, and to investigate the reproducibility of normalized ADC (nADC) value with the spleen as the reference organ. Thirty enrolled healthy volunteers received DWI with GE 1.5T, Siemens 1.5T, and Philips 3.0T magnetic resonance (MR) systems on liver and spleen (session 1) and were imaged again after 10 to 14 days using only GE 1.5T MR and Philips 3.0T MR systems (session 2). Interscan agreement and reproducibility of ADC measurements of liver and the calculated nADC values (ADCliver/ADCspleen) were statistically evaluated between 2 sessions. In session 1, ADC and nADC values of liver were evaluated for the scanner-related variability by 2-way analysis of variance and intraclass correlation coefficients (ICCs). Coefficients of variation (CVs) of ADCs and nADCs of liver were calculated for both 1.5 and 3.0-T MR system. Interscan agreement and reproducibility of ADC measurements of liver and related nADCs between 2 sessions were found to be satisfactory with ICC values of 0.773 to 0.905. In session 1, the liver nADCs obtained from different scanners were consistent (P = 0.112) without any significant difference in multiple comparison (P = 0.117 to >0.99) by using 2-way analysis of variance with post-hoc analysis of Bonferroni method, although the liver ADCs varied significantly (P < 0.001). nADCs measured by 3 scanners were in good interscanner agreements with ICCs of 0.685 to 0.776. The mean CV of nADCs of both 1.5T MR scanners (9.6%) was similar to that of 3.0T MR scanner (8.9%). ADCs measured at 3 MR scanners with different field strengths and vendors
Radon diffusion coefficients in soils of varying moisture content
NASA Astrophysics Data System (ADS)
Papachristodoulou, C.; Ioannides, K.; Pavlides, S.
2009-04-01
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.
Experimental investigation of the iodine partition coefficient
Kelly, J.L.; Babad, C.J.; Mulder, R.U.
1985-11-01
Short-term values of the iodine partition coefficient (IPC) were evaluated experimentally by an air/water system over the following ranges of conditions: temperature = 25 to 70/sup 0/C, pH = 5 to 9, and iodine concentration = 10/sup -9/ to 10/sup -2/ kg iodine/m/sup 3/ H/sub 2/O. The experimental IPC values are relatively independent of temperature over the indicated range, but show a significant dependence on pH and iodine concentration. In basic solutions the short-term values are several orders of magnitude less than the true equilibrium values; in acid solutions, the differences are much less. These results are useful for predicting the disposition of iodine shortly (i.e., 1 to 10 h) after iodine has been released into an air/water environment.
Transport Coefficients in weakly compressible turbulence
NASA Technical Reports Server (NTRS)
Rubinstein, Robert; Erlebacher, Gordon
1996-01-01
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.
Coefficient of restitution for a superelastic collision
NASA Astrophysics Data System (ADS)
Cross, Rod
2017-03-01
A simple experiment is described where the tip of a metal ruler is used to strike a 50 g mass. Since the ruler is very flexible, the impact duration is much longer than usual, giving the impression that the ruler simply pushes the mass forward at low speed over a long distance. The tip of the ruler remains in contact with the mass throughout the impact. However, the impact is best described as a long duration collision with a coefficient of restitution (COR) greater than zero, despite the fact that the relative speed during and at the end of the collision is zero. If the mass rests on a table and if the ruler strikes the table before striking the mass, then the ruler bends and stores elastic energy. The result is a superelastic collision where the COR is greater than unity.
Transport coefficients for dense metal plasmas
NASA Astrophysics Data System (ADS)
Kuhlbrodt, Sandra; Redmer, Ronald
2000-11-01
Thermoelectric transport coefficients of metal plasmas are calculated within the linear response theory applied previously to determine the electrical conductivity of Al and Cu plasmas [R. Redmer, Phys. Rev. E 59, 1073 (1999)]. We consider temperatures of 1-3 eV and densities of 0.001-1 g/cm3 as relevant in rapid wire evaporation experiments. The plasma composition is calculated considering higher ionization stages of atoms up to 5+, and solving the respective system of coupled mass action laws. Interactions between charged particles are treated on T matrix level. Results for the electrical conductivity of various metal plasmas are in reasonable agreement with experimental data. Thermal conductivity and thermopower are also given. In addition, we compare with experimental data for temperatures up to 25 eV and liquidlike densities.
Clustering stocks using partial correlation coefficients
NASA Astrophysics Data System (ADS)
Jung, Sean S.; Chang, Woojin
2016-11-01
A partial correlation analysis is performed on the Korean stock market (KOSPI). The difference between Pearson correlation and the partial correlation is analyzed and it is found that when conditioned on the market return, Pearson correlation coefficients are generally greater than those of the partial correlation, which implies that the market return tends to drive up the correlation between stock returns. A clustering analysis is then performed to study the market structure given by the partial correlation analysis and the members of the clusters are compared with the Global Industry Classification Standard (GICS). The initial hypothesis is that the firms in the same GICS sector are clustered together since they are in a similar business and environment. However, the result is inconsistent with the hypothesis and most clusters are a mix of multiple sectors suggesting that the traditional approach of using sectors to determine the proximity between stocks may not be sufficient enough to diversify a portfolio.
Effective Electrocardiogram Steganography Based on Coefficient Alignment.
Yang, Ching-Yu; Wang, Wen-Fong
2016-03-01
This study presents two types of data hiding methods based on coefficient alignment for electrocardiogram (ECG) signals, namely, lossy and reversible ECG steganographys. The lossy method is divided into high-quality and high-capacity ECG steganography, both of which are capable of hiding confidential patient data in ECG signals. The reversible data hiding method can not only hide secret messages but also completely restore the original ECG signal after bit extraction. Simulations confirmed that the perceived quality generated by the lossy ECG steganography methods was good, while hiding capacity was acceptable. In addition, these methods have a certain degree of robustness, which is rare in conventional ECG stegangraphy schemes. Moreover, the proposed reversible ECG steganography method can not only successfully extract hidden messages but also completely recover the original ECG data.
Manning's roughness coefficient for Illinois streams
Soong, David T.; Prater, Crystal D.; Halfar, Teresa M.; Wobig, Loren A.
2012-01-01
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 http://il.water.usgs.gov/proj/nvalues/.
Optical absorption coefficients of pure water
NASA Astrophysics Data System (ADS)
Lu, Zheng; Zhao, Xianzhen; Fry, Edward S.
2002-10-01
The integrating cavity absorption meter(ICAM), which is independent of scattering effect, is used to measure the absolute values of small optical absorption coefficients of liquid. A modified ICAM is being used to measure the absorption of water in the wavelength range 300 to 700 nm. The ultrapure water produced by a two-stages water purification system reaches Type I quality. This is equal to or better than ASTM,CAP and NCCLS water quality standards. To avoid the fact that dissolved oxygen absorbs ultraviolet light due to the photochemical effect, the water sample is delivered through a nitrogen sealed system which will prevent the sample from contacting with oxygen. A compassion of our absorption spectrum with other existing data is given.
Upper bounds for flexoelectric coefficients in ferroelectrics
NASA Astrophysics Data System (ADS)
Yudin, P. V.; Ahluwalia, R.; Tagantsev, A. K.
2014-02-01
Flexoelectric effect is the response of electric polarization to the mechanical strain gradient. At the nano-scale, where large strain gradients are expected, the flexoelectric effect becomes appreciable and may substitute piezoelectric effect in centrosymmetric materials. These features make flexoelectricity of growing interest during the last decade. At the same time, the available theoretical and experimental results are rather contradictory. In particular, experimentally measured flexoelectric coefficients in some ferroelectric materials largely exceed theoretically predicted values. Here, we determine the upper limits for the magnitude of the static bulk contribution to the flexoelectric effect in ferroelectrics, the contribution which was customarily considered as the dominating one. The magnitude of the upper bounds obtained suggests that the anomalously high flexoelectric coupling documented for perovskite ceramics can hardly be attributed to a manifestation of the static bulk effect.
Transport coefficients in superfluid neutron stars
Tolos, Laura; Manuel, Cristina; Sarkar, Sreemoyee; Tarrus, Jaume
2016-01-22
We study the shear and bulk viscosity coefficients as well as the thermal conductivity as arising from the collisions among phonons in superfluid neutron stars. We use effective field theory techniques to extract the allowed phonon collisional processes, written as a function of the equation of state and the gap of the system. The shear viscosity due to phonon scattering is compared to calculations of that coming from electron collisions. We also comment on the possible consequences for r-mode damping in superfluid neutron stars. Moreover, we find that phonon collisions give the leading contribution to the bulk viscosities in the core of the neutron stars. We finally obtain a temperature-independent thermal conductivity from phonon collisions and compare it with the electron-muon thermal conductivity in superfluid neutron stars.
Selective sorting of alpha-granule proteins.
Italiano, J E; Battinelli, E M
2009-07-01
One of the main functions of blood platelets is to secrete a variety of substances that can modify a developing thrombus, regulate the growth of the vasculature, promote wound repair, and contribute to cell-adhesive events. A majority of this vast array of secreted proteins are stored in alpha-granules. Until recently, it was assumed that platelets contained one homogeneous population of alpha-granules that undergo complete de-granulation during platelet activation. This review focuses on the mechanisms of alpha-granule biogenesis and secretion, with a particular emphasis on recent findings that clearly demonstrate that platelets contain distinct subpopulations of alpha-granules that undergo differential release during activation. We consider the implications of this new paradigm of platelet secretion, discuss mechanisms of alpha-granule biogenesis, and review the molecular basis of transport and delivery of alpha-granules to assembling platelets.
Partitioning coefficients between olivine and silicate melts
NASA Astrophysics Data System (ADS)
Bédard, J. H.
2005-08-01
Variation of Nernst partition coefficients ( D) between olivine and silicate melts cannot be neglected when modeling partial melting and fractional crystallization. Published natural and experimental olivine/liquidD data were examined for covariation with pressure, temperature, olivine forsterite content, and melt SiO 2, H 2O, MgO and MgO/MgO + FeO total. Values of olivine/liquidD generally increase with decreasing temperature and melt MgO content, and with increasing melt SiO 2 content, but generally show poor correlations with other variables. Multi-element olivine/liquidD profiles calculated from regressions of D REE-Sc-Y vs. melt MgO content are compared to results of the Lattice Strain Model to link melt MgO and: D0 (the strain compensated partition coefficient), EM3+ (Young's Modulus), and r0 (the size of the M site). Ln D0 varies linearly with Ln MgO in the melt; EM3+ varies linearly with melt MgO, with a dog-leg at ca. 1.5% MgO; and r0 remains constant at 0.807 Å. These equations are then used to calculate olivine/liquidD for these elements using the Lattice Strain Model. These empirical parameterizations of olivine/liquidD variations yield results comparable to experimental or natural partitioning data, and can easily be integrated into existing trace element modeling algorithms. The olivine/liquidD data suggest that basaltic melts in equilibrium with pure olivine may acquire small negative Ta-Hf-Zr-Ti anomalies, but that negative Nb anomalies are unlikely to develop. Misfits between results of the Lattice Strain Model and most light rare earth and large ion lithophile partitioning data suggest that kinetic effects may limit the lower value of D for extremely incompatible elements in natural situations characterized by high cooling/crystallization rates.
Partition coefficients of organic contaminants with carbohydrates.
Hung, Hsu-Wen; Lin, Tsair-Fuh; Chiou, Cary T
2010-07-15
In view of the current lack of reliable partition coefficients for organic compounds with carbohydrates (K(ch)), carefully measured values with cellulose and starch, the two major forms of carbohydrates, are provided for a wide range of compounds: short-chain chlorinated hydrocarbons, halogenated benzenes, alkyl benzenes, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, and organochlorine pesticides. To ensure the accuracy of the K(ch) data, solute concentrations in both water and carbohydrate phases are measured by direct solvent extraction of the samples. For a given compound, the observed partition coefficient with cellulose (K(cl)) is virtually the same as that with starch (K(st)). This finding expedites the evaluation of organic contamination with different forms of carbohydrates. The presently determined K(ch) values of 13 PAHs are substantially lower (by 3-66 times) than the literature data; the latter are suspect as they were obtained with (i) presumably impure carbohydrate samples or (ii) indirectly measured equilibrium solute concentrations in carbohydrate and water phases. Although the K(ch) values are generally considerably lower than the respective K(ow) (octanol-water) or K(lipid) (lipid-water), accurate K(ch) data are duly required to accurately estimate the contamination of carbohydrates by organic compounds because of the abundance of carbohydrates over lipids in crops and plants. To overcome the current lack of reliable K(ch) data for organic compounds, a close correlation of log K(ch) with log K(ow) has been established for predicting the unavailable K(ch) data for low-polarity compounds.
Apparent diffusion coefficient of normal adrenal glands*
Teixeira, Sara Reis; Elias, Paula Condé Lamparelli; Leite, Andrea Farias de Melo; de Oliveira, Tatiane Mendes Gonçalves; Muglia, Valdair Francisco; Elias Junior, Jorge
2016-01-01
Objective To assess the feasibility and reliability of apparent diffusion coefficient (ADC) measurements of normal adrenal glands. Materials and methods This was a retrospective study involving 32 healthy subjects, divided into two groups: prepubertal (PreP, n = 12), aged from 2 months to 12.5 years (4 males; 8 females); and postpubertal (PostP, n = 20), aged from 11.9 to 61 years (5 males; 15 females). Diffusion-weighted magnetic resonance imaging (DW-MRI) sequences were acquired at a 1.5 T scanner using b values of 0, 20, 500, and 1000 s/mm2. Two radiologists evaluated the images. ADC values were measured pixel-by-pixel on DW-MRI scans, and automatic co-registration with the ADC map was obtained. Results Mean ADC values for the right adrenal glands were 1.44 × 10-3 mm2/s for the PreP group and 1.23 × 10-3 mm2/s for the PostP group, whereas they were 1.58 × 10-3 mm2/s and 1.32 × 10-3 mm2/s, respectively, for the left glands. ADC values were higher in the PreP group than in the PostP group (p < 0.05). Agreement between readers was almost perfect (intraclass correlation coefficient, 0.84-0.94; p < 0.05). Conclusion Our results demonstrate the feasibility and reliability of performing DW-MRI measurements of normal adrenal glands. They could also support the feasibility of ADC measurements of small structures. PMID:28057963
Alpha-1 antitrypsin augmentation therapy.
Wewers, Mark D; Crystal, Ronald G
2013-03-01
The therapy of alpha-1 antitrypsin deficiency (AATD) is an example of a medical triumph over a common hereditary disease. Based on the understanding of the pathogens of the disease as a deficiency in liver production of alpha-1 antitrypsin (AAT) resulting from inherited genetic variation in both parental AAT genes, the knowledge that A1AT functions primarily to inhibit neutrophil elastase (NE), and the observation that NE instilled into the lung of experimental animals resulted in emphysema, the concept evolved that the pulmonary manifestations of the disease could be halted by intermittent intravenous infusions of AAT purified from pooled human plasma. Following preliminary clinical studies in the academic community, and then pharmaceutical company development of large scale purification of human AAT, the FDA approved the use of weekly AAT augmentation therapy for AATD following a clinical trial which demonstrated that weekly infusions would raise to normal plasma and lung epithelial fluid levels of AAT in AAT-deficient individuals. The therapy is now used worldwide to treat AATD, the only pulmonary genetic disease with effective therapy for all affected individuals.
The origin and age of the Alpha-Mendeleev and Lomonosov ridges in the Amerasia Basin
NASA Astrophysics Data System (ADS)
Verzhbitskii, E. V.; Lobkovskii, L. I.; Byakov, A. F.; Kononov, M. V.
2013-02-01
The results of the bathymetry simulation indicate the emplacement of the Mesozoic Arctic plume into the lithosphere of the Alpha-Mendeleev and Lomonosov ridges. The study also presents a model of the thermal subsidence to the asthenosphere. The calculated coefficients are compared with those obtained for the Greenland-Iceland and Iceland-Faeroe ridges, which were formed in response to hotspot activity. It was shown that the coefficients of the thermal subsidence in the central part of the Alpha-Mendeleev and Lomonosov Ridges are similar to those calculated for the Greenland-Iceland and Iceland-Faeroe ridges. This indicates the thermal regime of the subsidence of the Alpha-Mendeleev and Lomonosov ridges since the Early Miocene and the increased influence of the Arctic plume on the ridge genesis. The ridges are interpreted to have formed over a broad geological timeframe, from the late Cretaceous to the Cenozoic. A geothermal method, which is highly informative in terms of the age of the lithosphere, provides better constraints on the timing of ridge formation. The age estimates for the Alpha-Mendeleev (97-79 Ma) and Lomonosov ridges (69-57 Ma) derived from the geothermal data allowed us to draw a convincing conclusion about the genesis of these ridges.
Partnership of PGC-1alpha and HNF4alpha in the regulation of lipoprotein metabolism.
Rhee, James; Ge, Hongfei; Yang, Wenli; Fan, Melina; Handschin, Christoph; Cooper, Marcus; Lin, Jiandie; Li, Cai; Spiegelman, Bruce M
2006-05-26
Peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) is a transcriptional coactivator involved in several aspects of energy metabolism. It is induced or activated under different stimuli in a highly tissue-specific manner and subsequently partners with certain transcription factors in those tissues to execute various biological programs. In the fasted liver, PGC-1alpha is induced and interacts with hepatocyte nuclear factor 4alpha (HNF4alpha) and other transcription factors to activate gluconeogenesis and increase hepatic glucose output. Given the broad spectrum of liver genes responsive to HNF4alpha, we sought to determine those that were specifically targeted by the combination of PGC-1alpha and HNF4alpha. Coexpression of these two molecules in murine stem cells reveals a high induction of mRNA for apolipoproteins A-IV and C-II. Forced expression of PGC-1alpha in mouse and human hepatoma cells increases the mRNA of a subset of apolipoproteins implicated in very low density lipoprotein and triglyceride metabolism, including apolipoproteins A-IV, C-II, and C-III. Coactivation of the apoC-III/A-IV promoter region by PGC-1alpha occurs through a highly conserved HNF4alpha response element, the loss of which completely abolishes activation by PGC-1alpha and HNF4alpha. Adenoviral infusion of PGC-1alpha into live mice increases hepatic expression of apolipoproteins A-IV, C-II, and C-III and increases serum and very low density lipoprotein triglyceride levels. Conversely, knock down of PGC-1alpha in vivo causes a decrease in both apolipoprotein expression and serum triglyceride levels. These data point to a crucial role for the PGC-1alpha/HNF4alpha partnership in hepatic lipoprotein metabolism.
Beta/alpha continuous air monitor
Becker, Gregory K.; Martz, Dowell E.
1989-01-01
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.
Beta/alpha continuous air monitor
Becker, G.K.; Martz, D.E.
1988-06-27
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.
ERIC Educational Resources Information Center
Halsall, H. B.; Wermeling, J. R.
1982-01-01
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…
Adler, Jeremy; Parmryd, Ingela
2010-08-01
The Pearson correlation coefficient (PCC) and the Mander's overlap coefficient (MOC) are used to quantify the degree of colocalization between fluorophores. The MOC was introduced to overcome perceived problems with the PCC. The two coefficients are mathematically similar, differing in the use of either the absolute intensities (MOC) or of the deviation from the mean (PCC). A range of correlated datasets, which extend to the limits of the PCC, only evoked a limited response from the MOC. The PCC is unaffected by changes to the offset while the MOC increases when the offset is positive. Both coefficients are independent of gain. The MOC is a confusing hybrid measurement, that combines correlation with a heavily weighted form of co-occurrence, favors high intensity combinations, downplays combinations in which either or both intensities are low and ignores blank pixels. The PCC only measures correlation. A surprising finding was that the addition of a second uncorrelated population can substantially increase the measured correlation, demonstrating the importance of excluding background pixels. Overall, since the MOC is unresponsive to substantial changes in the data and is hard to interpret, it is neither an alternative to nor a useful substitute for the PCC. The MOC is not suitable for making measurements of colocalization either by correlation or co-occurrence.
Gene transfer mediated by alpha2-macroglobulin.
Schneider, H; Huse, K; Birkenmeier, G; Otto, A; Scholz, G H
1996-01-01
alpha2-Macroglobulin covalently linked to poly(L)-lysine can be used as a vehicle for receptor-mediated gene transfer. This modified alpha2-macroglobulin maintains its ability to bind to the alpha2-macroglobulin receptor, and was shown to introduce a luciferase reporter gene plasmid into HepG2 human hepatoma cells in vitro. The alpha2-macroglobulin receptor is a very large and multifunctional cell surface receptor, whose rapid and efficient internalization rate makes it attractive for gene therapy, e.g. for hepatic gene targeting via injection into the portal vein. PMID:8871570
Prospects for alpha particle studies on TFTR
Zweben, S.J.
1987-05-01
TFTR is expected to produce approximately 5 MW of alpha heating during the D/T Q approx. = 1 phase of operation in 1990. At that point the collective confinement properties and the heating effects of alpha particles become accessible for study for the first time. This paper outlines the potential performance of TFTR with respect to alpha particle production, the diagnostics which will be available for alpha particle measurements, and the physics issues which can be studied both before and during D/T operation.
The Attenuation of Correlation Coefficients: A Statistical Literacy Issue
ERIC Educational Resources Information Center
Trafimow, David
2016-01-01
Much of the science reported in the media depends on correlation coefficients. But the size of correlation coefficients depends, in part, on the reliability with which the correlated variables are measured. Understanding this is a statistical literacy issue.
EEG, alpha waves and coherence
NASA Astrophysics Data System (ADS)
Ascolani, Gianluca
This thesis addresses some theoretical issues generated by the results of recent analysis of EEG time series proving the brain dynamics are driven by abrupt changes making them depart from the ordinary Poisson condition. These changes are renewal, unpredictable and non-ergodic. We refer to them as crucial events. How is it possible that this form of randomness be compatible with the generation of waves, for instance alpha waves, whose observation seems to suggest the opposite view the brain is characterized by surprisingly extended coherence? To shed light into this apparently irretrievable contradiction we propose a model based on a generalized form of Langevin equation under the influence of a periodic stimulus. We assume that there exist two different forms of time, a subjective form compatible with Poisson statistical physical and an objective form that is accessible to experimental observation. The transition from the former to the latter form is determined by the brain dynamics interpreted as emerging from the cooperative interaction among many units that, in the absence of cooperation would generate Poisson fluctuations. We call natural time the brain internal time and we make the assumption that in the natural time representation the time evolution of the EEG variable y(t) is determined by a Langevin equation perturbed by a periodic process that in this time representation is hardly distinguishable from an erratic process. We show that the representation of this random process in the experimental time scale is characterized by a surprisingly extended coherence. We show that this model generates a sequence of damped oscillations with a time behavior that is remarkably similar to that derived from the analysis of real EEG's. The main result of this research work is that the existence of crucial events is not incompatible with the alpha wave coherence. In addition to this important result, we find another result that may help our group, or any other research
Probability density of the empirical wavelet coefficients of a noisy chaos
NASA Astrophysics Data System (ADS)
Garcin, Matthieu; Guégan, Dominique
2014-05-01
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.
Tessier, Peter M; Sandler, Stanley I; Lenhoff, Abraham M
2004-05-01
The importance of weak protein interactions, such as protein self-association, is widely recognized in a variety of biological and technological processes. Although protein self-association has been studied extensively, much less attention has been devoted to weak protein cross-association, mainly due to the difficulties in measuring weak interactions between different proteins in solution. Here a framework is presented for quantifying the osmotic second virial cross coefficient directly using a modified form of self-interaction chromatography called cross-interaction chromatography. A theoretical relationship is developed between the virial cross coefficient and the chromatographic retention using statistical mechanics. Measurements of bovine serum albumin (BSA)/lysozyme cross-association using cross-interaction chromatography agree well with the few osmometry measurements available in the literature. Lysozyme/alpha-chymotrypsinogen interactions were also measured over a wide range of solution conditions, and some counterintuitive trends were observed that may provide new insight into the molecular origins of weak protein interactions. The virial cross coefficients presented in this work may also provide insight into separation processes that are influenced by protein cross-interactions, such as crystallization, precipitation, and ultrafiltration.
Lee, Young-Su; Lee, Myoung-Hee; Lee, Hee-Seob; Lee, Seung-Jae; Kim, Young-Wan; Zhang, Ran; Withers, Stephen G; Kim, Kwan Soo; Lee, Sung-Joon; Park, Kwan-Hwa
2008-07-09
Here, we describe the enzymatic synthesis of novel inhibitors using acarviosine-glucose as a donor and 3-alpha-D-glucopyranosylpropen (alphaGP) as an acceptor. Maltogenic amylase from Thermus sp. (ThMA) catalyzed the transglycosylation of the acarviosine moiety to alphaGP. The two major reaction products were isolated using chromatographies. Structural analyses revealed that acarviosine was transferred to either C-7 or C-9 of the alphaGP, which correspond to C-4 and C-6 of glucose. Both inhibited rat intestine alpha-glucosidase competitively but displayed a mixed-type inhibition mode against human pancreatic alpha-amylase. The alpha-acarviosinyl-(1-->7)-3-alpha-D-glucopyranosylpropen showed weaker inhibition potency than acarbose against both alpha-glycosidases. In contrast, the alpha-acarviosinyl-(1-->9)-3-alpha-D-glucopyranosylpropen exhibited a 3.0-fold improved inhibition potency against rat intestine alpha-glucosidase with 0.3-fold inhibition potency against human pancreatic alpha-amylase relative to acarbose. In conclusion, alpha-acarviosinyl-(1-->9)-3-alpha-D-glucopyranosylpropen is a novel alpha-glucosidase-selective inhibitor with 10-fold enhanced selectivity toward alpha-glucosidase over alpha-amylase relative to acarbose, and it could be applied as a potent hypoglycemic agent.
Phonon anharmonicity and Gruneisen parameters of alpha-plutonium
NASA Astrophysics Data System (ADS)
Filanovich, A. N.; Povzner, A. A.
2015-12-01
A self-consistent thermodynamic model of alpha-phase of plutonium is constructed. The calculations of thermal and elastic properties of α-Pu, carried out within this model, demonstrate that anomalously strong temperature dependence of the bulk modulus and unusually high value of the coefficient of thermal expansion of α-Pu are caused by its strong lattice anharmonicity. The isothermal and isobaric Gruneisen parameters of α-Pu and δ-Pu Pu0.96Ga0.04 are calculated. It is shown that wide spread of the values of Gruneisen parameter of α-Pu, obtained previously from different experimental data, is explained by the dependence of Gruneisen parameter of α-Pu on temperature.
Mathematical model of an air-filled alpha stirling refrigerator
NASA Astrophysics Data System (ADS)
McFarlane, Patrick; Semperlotti, Fabio; Sen, Mihir
2013-10-01
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.
Review of analysis methods for rotating systems with periodic coefficients
NASA Technical Reports Server (NTRS)
Dugundji, J.; Wendell, J. H.
1981-01-01
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.
46 CFR 42.20-25 - Correction for block coefficient.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 46 Shipping 2 2010-10-01 2010-10-01 false Correction for block coefficient. 42.20-25 Section 42.20-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Freeboards § 42.20-25 Correction for block coefficient. If the block coefficient...
46 CFR 42.20-25 - Correction for block coefficient.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 46 Shipping 2 2011-10-01 2011-10-01 false Correction for block coefficient. 42.20-25 Section 42.20-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Freeboards § 42.20-25 Correction for block coefficient. If the block coefficient...
Detection Performance of the Circular Correlation Coefficient Receiver,
of the squared modulus of the circular serial correlation coefficient is found when no signal is present, allowing computation of the detection...threshold. For small data records, as is typical in radar applications, the performance of the correlation coefficient detector is compared to a standard... Correlation Coefficient , Autoregressive, CFAR, Autocorrelation Estimation, Radar Receiver, and Digital Signal Processing.
46 CFR 42.20-25 - Correction for block coefficient.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 46 Shipping 2 2014-10-01 2014-10-01 false Correction for block coefficient. 42.20-25 Section 42.20-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Freeboards § 42.20-25 Correction for block coefficient. If the block coefficient...
46 CFR 42.20-25 - Correction for block coefficient.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 46 Shipping 2 2013-10-01 2013-10-01 false Correction for block coefficient. 42.20-25 Section 42.20-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Freeboards § 42.20-25 Correction for block coefficient. If the block coefficient...
46 CFR 42.20-25 - Correction for block coefficient.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 46 Shipping 2 2012-10-01 2012-10-01 false Correction for block coefficient. 42.20-25 Section 42.20-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Freeboards § 42.20-25 Correction for block coefficient. If the block coefficient...
On some properties of SU(3) fusion coefficients
NASA Astrophysics Data System (ADS)
Coquereaux, Robert; Zuber, Jean-Bernard
2016-11-01
Three aspects of the SU(3) fusion coefficients are revisited: the generating polynomials of fusion coefficients are written explicitly; some curious identities generalizing the classical Freudenthal-de Vries formula are derived; and the properties of the fusion coefficients under conjugation of one of the factors, previously analyzed in the classical case, are extended to the affine algebra su ˆ (3) at finite level.
On Estimation and Hypothesis Testing Problems for Correlation Coefficients
ERIC Educational Resources Information Center
Kraemer, Helena Chmura
1975-01-01
A selection of statistical problems commonly encountered in psychological or psychiatric research concerning correlation coefficients are re-evaluated in the light of recently developed simplifications in the forms of the distribution theory of the intraclass correlation coefficient, of the product-moment correlation coefficient, and the Spearman…
An Investigation of the Sampling Distribution of the Congruence Coefficient.
ERIC Educational Resources Information Center
Broadbooks, Wendy J.; Elmore, Patricia B.
This study developed and investigated an empirical sampling distribution of the congruence coefficient. The effects of sample size, number of variables, and population value of the congruence coefficient on the sampling distribution of the congruence coefficient were examined. Sample data were generated on the basis of the common factor model and…
40 CFR 721.10300 - Benzeneacetic acid, .alpha.-chloro-.alpha.-phenyl-, ethyl ester.
Code of Federal Regulations, 2014 CFR
2014-07-01
...-.alpha.-phenyl-, ethyl ester. 721.10300 Section 721.10300 Protection of Environment ENVIRONMENTAL....-phenyl-, ethyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as benzeneacetic acid, .alpha.-chloro-.alpha.-phenyl-, ethyl ester (PMN...
40 CFR 721.10300 - Benzeneacetic acid, .alpha.-chloro-.alpha.-phenyl-, ethyl ester.
Code of Federal Regulations, 2012 CFR
2012-07-01
...-.alpha.-phenyl-, ethyl ester. 721.10300 Section 721.10300 Protection of Environment ENVIRONMENTAL....-phenyl-, ethyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as benzeneacetic acid, .alpha.-chloro-.alpha.-phenyl-, ethyl ester (PMN...
40 CFR 721.10300 - Benzeneacetic acid, .alpha.-chloro-.alpha.-phenyl-, ethyl ester.
Code of Federal Regulations, 2013 CFR
2013-07-01
...-.alpha.-phenyl-, ethyl ester. 721.10300 Section 721.10300 Protection of Environment ENVIRONMENTAL....-phenyl-, ethyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as benzeneacetic acid, .alpha.-chloro-.alpha.-phenyl-, ethyl ester (PMN...
Resting-State Alpha in Autism Spectrum Disorder and Alpha Associations with Thalamic Volume
ERIC Educational Resources Information Center
Edgar, J. Christopher; Heiken, Kory; Chen, Yu-Han; Herrington, John D.; Chow, Vivian; Liu, Song; Bloy, Luke; Huang, Mingxiong; Pandey, Juhi; Cannon, Katelyn M.; Qasmieh, Saba; Levy, Susan E.; Schultz, Robert T.; Roberts, Timothy P. L.
2015-01-01
Alpha circuits (8-12 Hz), necessary for basic and complex brain processes, are abnormal in autism spectrum disorder (ASD). The present study obtained estimates of resting-state (RS) alpha activity in children with ASD and examined associations between alpha activity, age, and clinical symptoms. Given that the thalamus modulates cortical RS alpha…
Gopal-Srivastava, R; Piatigorsky, J
1993-11-01
The murine alpha B-crystallin gene (a member of the small heat shock protein family) is expressed constitutively at high levels in the lens and at lower levels in many other tissues, including skeletal muscle. We have previously used the herpes simplex virus thymidine kinase promoter fused to the human growth hormone gene to identify an alpha B-crystallin enhancer at positions -427 to -259 that has high activity in muscle and low activity in lens cell lines. In the study reported here, we performed DNase I footprinting, transfection, mutagenesis, and electrophoretic mobility shift experiments using the murine C2C12 muscle and alpha TN4-1 lens cell lines and the rabbit N/N1003A lens cell line to identify sequences responsible for activity of this enhancer. Enhancer activity in both the muscle and lens cells was dependent on novel elements called alpha BE-1 (-407 to -397), alpha BE-2 (-360 to -327), and alpha BE-3 (-317 to -306). These elements were also weakly occupied by nuclear proteins in L929 cells, which appear to express the alpha B-crystallin gene at a very low level (detectable only by the polymerase chain reaction). A fourth element containing a consensus muscle regulatory factor-binding site called MRF (-300 to -288) was occupied and used only by the C2C12 muscle cells. Cotransfection in NIH 3T3 cells and antibody-gel shift experiments using C2C12 nuclear extracts indicated that MyoD, myogen, or a similar member of this family can activate the alpha B-crystallin enhancer by interaction with the MRF site. Taken together, we conclude that the alpha BE-1, alpha BE-2, and alpha BE-3 elements are shared by both lens and muscle cells, but the MRF element is used only in muscle cells, providing the first example of a muscle-specific control element in a crystallin gene.
Li, Xiaoqi; Jiang, Huabei
2013-02-21
We present a study through extensive simulation that considers the impact of inhomogeneous optical scattering coefficient distribution on recovery of optical absorption coefficient maps using tomographic photoacoustic data collected from media mimicking breast tissue. We found that while the impact of scattering heterogeneities/targets is modest on photoacoustic recovery of optical absorption coefficients, the impact of scattering contrast caused by adipose tissue, a layer of normal tissue along the boundary of the breast, is dramatic on reconstruction of optical absorption coefficients using photoacoustic data-up to 25.8% relative error in recovering the absorption coefficient is estimated in such cases. To overcome this problem, we propose a new method to enhance photoacoustic recovery of the optical absorption coefficient in heterogeneous media by considering inhomogeneous scattering coefficient distribution provided by diffuse optical tomography (DOT). Results from extensive simulations show that photoacoustic recovery of absorption coefficient maps can be improved considerably with a priori scattering information from DOT.
Sedimentation coefficient distributions of large particles.
Schuck, Peter
2016-07-21
The spatial and temporal evolution of concentration boundaries in sedimentation velocity analytical ultracentrifugation reports on the size distribution of particles with high hydrodynamic resolution. For large particles such as large protein complexes, fibrils, viral particles, or nanoparticles, sedimentation conditions usually allow migration from diffusion to be neglected relative to sedimentation. In this case, the shape of the sedimentation boundaries of polydisperse mixtures relates directly to the underlying size-distributions. Integral and derivative methods for calculating sedimentation coefficient distributions g*(s) of large particles from experimental boundary profiles have been developed previously, and are recapitulated here in a common theoretical framework. This leads to a previously unrecognized relationship between g*(s) and the time-derivative of concentration profiles. Of closed analytical form, it is analogous to the well-known Bridgman relationship for the radial derivative. It provides a quantitative description of the effect of substituting the time-derivative by scan differences with finite time intervals, which appears as a skewed box average of the true distribution. This helps to theoretically clarify the differences between results from time-derivative method and the approach of directly fitting the integral definition of g*(s) to the entirety of experimental boundary data.
Second virial coefficients of asymmetric top molecules.
Wormer, Paul E S
2005-05-08
A short self-contained derivation is given for the second virial coefficient B2(T) of a gas consisting of identical interacting asymmetric rigid rotors. The resulting expression is correct through variant Planck's over h2. First, the canonical partition function is derived by means of an variant Planck's over h expansion of exp[-H/(k(B)T)] due to Friedmann [Adv. Chem. Phys. 4, 225 (1962)]. The present work applies angular momentum operators and known facts from angular momentum theory. It is considerably more accessible than Friedmann's exposition, which is not based on angular momentum operators, but instead on explicit derivatives with respect to Euler angles. The partition function obtained from the variant Planck's over h expansion is applied to the derivation of an expression for B2(T) that is identical in appearance to the expression for symmetric rotors of T Pack [J. Chem. Phys. 78, 7217 (1983)]. The final equation in this work is valid for rigid rotors of any symmetry.
Zernike coefficients: are they really enough?
NASA Astrophysics Data System (ADS)
Progler, Christopher J.; Wong, Alfred K. K.
2000-07-01
Zernike aberration coefficients are routinely used in simulation exercises for lithographic printing and the discovery of Zernike values is considered strategic for many lithographic process engineers. Thanks to progress in actinic interferometry and resist based evaluation techniques, reliable estimates of Zernike component magnitudes are possible in many cases. It is expected that wavelength reductions from 248 nm and 193 nm to 157 nm along with continued use of aspheric elements in high NA designs will lead to an increase in the component of wavefront aberration that is not adequately characterized by a 36 term Zernike polynomial. Wavefront errors not well characterized by a conventional Zernike fit are variously termed mid- spatial frequency errors, lack of fit, residuals, flare, scatter etc. This paper explores the importance, characterization and analysis of these residual errors and attempts to clarify the boundaries between the various classes of wavefront error. We find that an accurate assessment an model of lens performance requires the inclusion of both residual wavefront errors and flare effects in addition to the customary 36 term Zernike expansion.
Transport coefficients of soft repulsive particle fluids
NASA Astrophysics Data System (ADS)
Heyes, D. M.; Brańka, A. C.
2008-03-01
Molecular dynamics computer simulation has been used to compute the self-diffusion coefficient, D, and shear viscosity, ηs, of soft-sphere fluids, in which the particles interact through the soft-sphere pair potential, phi(r) = epsilon(σ/r)n, where n measures the steepness or stiffness of the potential, epsilon and σ 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 (n\\to \\infty ) limit down to n = 4 over a range of densities. An ideal glass transition value was estimated from the limit where D and \\eta_{\\mathrm {s}}^{-1}\\to 0 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. n\\to \\infty ). 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.
Xen clusters in the alpha cages of zeolite KA
NASA Astrophysics Data System (ADS)
Jameson, Cynthia J.; Jameson, A. Keith; Gerald, Rex E., II; Lim, Hyung-Mi
1995-11-01
We have observed the individual signals of the Xen clusters (n=1-5) trapped in the alpha cages of zeolite KA. The 129Xe NMR chemical shift of each cluster in zeolite KA is larger than that of the corresponding Xen cluster in zeolite NaA. The temperature dependence of the chemical shifts of the clusters vary systematically with cluster size as they do in NaA, but the change of the temperature coefficients with n is somewhat more pronounced for Xen in the cages of KA than in NaA. The Xen chemical shifts and their variation with temperature are reproduced by the grand canonical Monte Carlo (GCMC) simulations. GCMC simulations of the distribution of the Xe atoms among the alpha cages in KA provide the fractions of cages containing n Xe atoms which agree reasonably well with the observed equilibrium distributions. The characteristics of Xe distribution and chemical shifts in KA are compared with that in NaA.
Stamateris, B.; Olivera-Fuentes, C.
1996-12-31
A new procedure is proposed for the calculation and correlation of cohesion parameters in cubic equations of state of the Van der Waals type. In this method, the derivative (rather than the function itself) is computed subject to the Maxwell (equal area) and Clapeyron equations. Strong experimental evidence indicates that properly formulated a functions must generate negative values at high temperatures. A theoretical analysis demonstrates the correct, hard-body limiting behavior of the cohesion function at infinite temperatures. From this, the simplest possible form of the cohesion function follows as a two-constant expression that can be considered an extension of a functional form previously proposed by Martin. The proposed function`s performance is comparable to more complex expressions previously presented in the literature, predicting vapor pressures of polar and nonpolar fluids with relative deviations (i) of {+-} 1%. 14 refs., 2 figs., 1 tab.
ERIC Educational Resources Information Center
Weng, Li-Jen
2004-01-01
A total of 1,247 college students participated in this study on the effect of scale format on the reliability of Likert-type rating scales. The number of response categories ranged from 3 to 9. Anchor labels on the scales were provided for each response option or for the end points only. The results indicated that the scales with few response…
NASA Astrophysics Data System (ADS)
Hollands, K. G. T.; Wright, J. L.
1983-01-01
This paper presents an efficient algorithm for solving the set of nonlinear equations governing the total heat transfer across an arbitrary number of parallel flat plate solar collector covers, each of which can be partly transparent to longwave thermal radiation. The governing equations are sufficiently general to permit each cover to have asymmetric radiative properties and to account for absorption of solar energy on the individual covers. This theory is shown to be in good agreement with the approximate equations of Whillier (provided certain interpretations are placed on his quantities) and with experiments using a plastic inner cover and bounding plates of various emissivities. Using this theory, it is demonstrated that if the absorber plate has a selective surface, an inner cover transparent to long wave radiation is to be preferred over one which is opaque.
Chi, Seung-Wook; Kim, Do-Hyoung; Olivera, Baldomero M.; McIntosh, J. Michael; Han, Kyou-Hoon . E-mail: khhan600@kribb.re.kr
2006-06-23
{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.
Remote Associates Test and Alpha Brain Waves
ERIC Educational Resources Information Center
Haarmann, Henk J.; George, Timothy; Smaliy, Alexei; Dien, Joseph
2012-01-01
Previous studies found that performance on the remote associates test (RAT) improves after a period of incubation and that increased alpha brain waves over the right posterior brain predict the emergence of RAT insight solutions. We report an experiment that tested whether increased alpha brain waves during incubation improve RAT performance.…
Alpha particle spectrometry using superconducting microcalorimeters
NASA Astrophysics Data System (ADS)
Horansky, Robert; Ullom, Joel; Beall, James; Hilton, Gene; Stiehl, Gregory; Irwin, Kent; Plionis, Alexander; Lamont, Stephen; Rudy, Clifford; Rabin, Michael
2009-03-01
Alpha spectrometry is the preferred technique for analyzing trace samples of radioactive material because the alpha particle flux can be significantly higher than the gamma-ray flux from nuclear materials of interest. Traditionally, alpha spectrometry is performed with Si detectors whose resolution is at best 8 keV FWHM. Here, we describe the design and operation of a microcalorimeter alpha detector with an energy resolution of 1.06 keV FWHM at 5 MeV. We demonstrate the ability of the microcalorimeter to clearly resolve the alpha particles from Pu-239 and Pu-240, whose ratio differentiates reactor-grade Pu from weapons-grade. We also show the first direct observation of the decay of Po-209 to the ground state of Pb-205 which has traditionally been obscured by a much stronger alpha line 2 keV away. Finally, the 1.06 keV resolution observed for alpha particles is far worse than the 0.12 keV resolution predicted from thermal fluctuations and measurement of gamma-rays. The cause of the resolution degradation may be ion damage in the tin. Hence, alpha particle microcalorimeters may provide a novel tool for studying ion damage and lattice displacement energies in bulk materials.
21 CFR 882.1610 - Alpha monitor.
Code of Federal Regulations, 2014 CFR
2014-04-01
... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Alpha monitor. 882.1610 Section 882.1610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1610 Alpha monitor. (a) Identification. An...
21 CFR 882.1610 - Alpha monitor.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Alpha monitor. 882.1610 Section 882.1610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1610 Alpha monitor. (a) Identification. An...
21 CFR 882.1610 - Alpha monitor.
Code of Federal Regulations, 2012 CFR
2012-04-01
... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Alpha monitor. 882.1610 Section 882.1610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1610 Alpha monitor. (a) Identification. An...
21 CFR 882.1610 - Alpha monitor.
Code of Federal Regulations, 2013 CFR
2013-04-01
... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Alpha monitor. 882.1610 Section 882.1610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1610 Alpha monitor. (a) Identification. An...
21 CFR 882.1610 - Alpha monitor.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Alpha monitor. 882.1610 Section 882.1610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1610 Alpha monitor. (a) Identification. An...
Monitoring pipes for residual alpha contamination
MacArthur, D.; Rawool-Sullivan, M.; Dockray, T.
1996-09-01
The sensitivity and application of traditional alpha monitors is limited by the short range of alpha particles in air and in solid materials. Detecting small amounts of alpha-emitting contamination inside pipes presents particular problems. The alpha particle cannot penetrate the walls of the pipe. Associated gamma-ray detection and active neutron interrogation is often used to detect large amounts of radioactive material in pipes, but these methods are of limited use for detecting small amounts of contamination. Insertion of a traditional alpha probes works well in large diameter straight pipes, but is increasingly difficult as the pipe network becomes smaller in diameter and more complex. Monitors based on long-range alpha detection (LRAD) detect ionization of the ambient air rather than the alpha particles themselves. A small fan draws the ions into an externally mounted ion detector. Thus, the air in the pipe serves as both the detector gas and the mechanism for transporting the alpha-induced ions to a detection grid outside the pipe. All of the ions created by all of the contamination in the pipe can be measured in a single detector. Since ambient air serves as the probe, crushed or twisted sections of pipe can be monitored almost as effectively as straight sections. The pipe monitoring system described in the paper was tested both at LANL and BNFL`s Sellafield reprocessing facility in the UK. In this paper, we report on the first field tests of the pipe monitoring system.
27 CFR 21.95 - Alpha terpineol.
Code of Federal Regulations, 2012 CFR
2012-04-01
... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Alpha terpineol. 21.95 Section 21.95 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... Alpha terpineol. (a) Boiling point at 752mm 218.8-219.4 °C. (b) Density at 15° 0.9386. (c)...
27 CFR 21.95 - Alpha terpineol.
Code of Federal Regulations, 2014 CFR
2014-04-01
... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Alpha terpineol. 21.95 Section 21.95 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... Alpha terpineol. (a) Boiling point at 752mm 218.8-219.4 °C. (b) Density at 15° 0.9386. (c)...
27 CFR 21.95 - Alpha terpineol.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Alpha terpineol. 21.95 Section 21.95 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... Alpha terpineol. (a) Boiling point at 752mm 218.8-219.4 °C. (b) Density at 15° 0.9386. (c)...
27 CFR 21.95 - Alpha terpineol.
Code of Federal Regulations, 2013 CFR
2013-04-01
... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Alpha terpineol. 21.95 Section 21.95 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... Alpha terpineol. (a) Boiling point at 752mm 218.8-219.4 °C. (b) Density at 15° 0.9386. (c)...
Elementary Processes Underlying Alpha Channeling in Tokamaks
NM.J. Fisch
2012-06-15
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
Atypical Alpha Asymmetry in Adults with ADHD
ERIC Educational Resources Information Center
Hale, T. Sigi; Smalley, Susan L.; Hanada, Grant; Macion, James; McCracken, James T.; McGough, James J.; Loo, Sandra K.
2009-01-01
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…
On the use of beta coefficients in meta-analysis.
Peterson, Robert A; Brown, Steven P
2005-01-01
This research reports an investigation of the use of standardized regression (beta) coefficients in meta-analyses that use correlation coefficients as the effect-size metric. The investigation consisted of analyzing more than 1,700 corresponding beta coefficients and correlation coefficients harvested from published studies. Results indicate that, under certain conditions, using knowledge of corresponding beta coefficients to input missing correlations (effect sizes) generally produces relatively accurate and precise population effect-size estimates. Potential benefits from applying this knowledge include smaller sampling errors because of increased numbers of effect sizes and smaller non-sampling errors because of the inclusion of a broader array of research designs.
Local Structure and Vibrational Properties of alpha-Pu, alpha-U, and the alpha-U Charge Density Wave
Nelson, E J; Allen, P G; Blobaum, K M; Wall, M A; Booth, C H
2004-08-10
The local atomic environment and vibrational properties of atoms in monoclinic pure {alpha}-plutonium as well as orthorhombic pure {alpha}-uranium and its low-temperature charge-density-wave (CDW) modulation are examined by extended x-ray absorption fine structure spectroscopy (EXAFS). Pu L{sub III}-edge and U L{sub III}-edge EXAFS data measured at low temperatures verify the crystal structures of {alpha}-U and {alpha}-Pu samples previously determined by x-ray diffraction and neutron scattering. Debye-Waller factors from temperature-dependent EXAFS measurements are fit with a correlated Debye model. The observed Pu-Pu bond correlated Debye temperature of {theta}{sub cD}({alpha}-Pu) = 162 {+-} 5 K for the pure {alpha}-Pu phase agrees with our previous measurement of the correlated Debye temperature of the gallium-containing {alpha}'-Pu phase in a mixed phase 1.9 at% Ga-doped {alpha}'-Pu/{delta}-Pu alloy. The temperature dependence of the U-U nearest neighbor Debye-Waller factor exhibits a sharp discontinuity in slope near T{sub CDW} = 43 K, the transition temperature at which the charge-density wave (CDW) in {alpha}-U condenses from a soft phonon mode along the (100) direction. Our measurement of the CDW using EXAFS is the first observation of the structure of the CDW in polycrystalline {alpha}-U. The different temperature dependence of the Debye-Waller factor for T < T{sub CDW} can be modeled by the change in bond length distributions resulting from condensation of the charge density wave. For T > T{sub CDW}, the observed correlated Debye temperature of {theta}{sub cD}({alpha}-U) = 199 {+-} 3 K is in good agreement with other measurements of the Debye temperature for polycrystalline {alpha}-U. CDW structural models fit to the {alpha}-U EXAFS data support a squared CDW at the lowest temperatures, with a displacement amplitude of {var_epsilon} = 0.05 {+-} 0.02 {angstrom}.
Incoming Engineering Students' Self-Assessment of Their Mathematical Background
ERIC Educational Resources Information Center
Guner, Necdet
2013-01-01
The aim of this study was to develop a tool to measure levels of mathematical knowledge gained in high school, as perceived by incoming engineering students. The study included 657 engineering students in the 2011-2012 academic year. Factor analysis was used to obtain a scale consisting of 47 items (Cronbach Alpha coefficient, 0.975). The…
Psychometric Analysis of Role Conflict and Ambiguity Scales in Academia
ERIC Educational Resources Information Center
Khan, Anwar; Yusoff, Rosman Bin Md.; Khan, Muhammad Muddassar; Yasir, Muhammad; Khan, Faisal
2014-01-01
A comprehensive Psychometric Analysis of Rizzo et al.'s (1970) Role Conflict & Ambiguity (RCA) scales were performed after its distribution among 600 academic staff working in six universities of Pakistan. The reliability analysis includes calculation of Cronbach Alpha Coefficients and Inter-Items statistics, whereas validity was determined by…
ERIC Educational Resources Information Center
Hua, Jing; Gu, Guixiong; Meng, Wei; Wu, Zhuochun
2013-01-01
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…
The Score Reliability of Draw-a-Person Intellectual Ability Test (DAP: IQ) for Rural Malawi Students
ERIC Educational Resources Information Center
Khasu, Denis S.; Williams, Thomas O., Jr.
2016-01-01
In this brief article, the reliability of scores for the Draw-A-Person Intellectual Ability Test for Children, Adolescents, and Adults (DAP: IQ; Reynolds & Hickman, 2004) was examined through several analyses with a sample of 147 children from rural Malawi, Africa using a Chichewa translation of instructions. Cronbach alpha coefficients for…
Linear Models for Item Scores: Reliability, Covariance Structure, and Psychometric Inference.
ERIC Educational Resources Information Center
Woodruff, David
Two analyses of variance (ANOVA) models for item scores are compared. The first is an items by subject random effect ANOVA. The second is a mixed effects ANOVA with items fixed and subjects random. Comparisons regarding reliability, Cronbach's alpha coefficient, psychometric inference, and inter-item covariance structure are made between the…
ERIC Educational Resources Information Center
Iji, Clement Onwu; Abah, Joshua Abah; Anyor, Joseph Wuave
2017-01-01
This study focused on the impact of cloud services on students' attitude towards mathematics education in public universities in Benue State, Nigeria. Ex-post facto research design was adopted for the study. The instrument for the study is the researcher-developed Cloud Service Impact Questionnaire--CSIQ (Cronbach Alpha Coefficient = 0.92). The…
Development of Social Media Addiction Test (SMAT17)
ERIC Educational Resources Information Center
Esgi, Necmi
2016-01-01
The aim of this study was to develop a test for assessing individuals' social media addiction; and conducting a reliability and validity study of this scale. Sample for this study was composed of 285 college students between the ages of 18 and 25. Reliability coefficients Cronbach's alpha value was 0.94 and Spearman Brown value was 0.91 for our…
ERIC Educational Resources Information Center
Kesan, Cenk; Ozkalkan, Zuhal; Iric, Hamdullah; Kaya, Deniz
2012-01-01
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…
A generalized concordance correlation coefficient for continuous and categorical data.
King, T S; Chinchilli, V M
2001-07-30
This paper discusses a generalized version of the concordance correlation coefficient for agreement data. The concordance correlation coefficient evaluates the accuracy and precision between two measures, and is based on the expected value of the squared function of distance. We have generalized this coefficient by applying alternative functions of distance to produce more robust versions of the concordance correlation coefficient. In this paper we extend the application of this class of estimators to categorical data as well, and demonstrate similarities to the kappa and weighted kappa statistics. We also introduce a stratified concordance correlation coefficient which adjusts for explanatory factors, and an extended concordance correlation coefficient which measures agreement among more than two responses. With these extensions, the generalized concordance correlation coefficient provides a unifying approach to assessing agreement among two or more measures that are either continuous or categorical in scale.
Catalytic Mechanism of Human Alpha-galactosidase
Guce, A.; Clark, N; Salgado, E; Ivanen, D; Kulinskaya, A; Brumer, H; Garman, S
2010-01-01
The enzyme {alpha}-galactosidase ({alpha}-GAL, also known as {alpha}-GAL A; E.C. 3.2.1.22) is responsible for the breakdown of {alpha}-galactosides in the lysosome. Defects in human {alpha}-GAL lead to the development of Fabry disease, a lysosomal storage disorder characterized by the buildup of {alpha}-galactosylated substrates in the tissues. {alpha}-GAL is an active target of clinical research: there are currently two treatment options for Fabry disease, recombinant enzyme replacement therapy (approved in the United States in 2003) and pharmacological chaperone therapy (currently in clinical trials). Previously, we have reported the structure of human {alpha}-GAL, which revealed the overall structure of the enzyme and established the locations of hundreds of mutations that lead to the development of Fabry disease. Here, we describe the catalytic mechanism of the enzyme derived from x-ray crystal structures of each of the four stages of the double displacement reaction mechanism. Use of a difluoro-{alpha}-galactopyranoside allowed trapping of a covalent intermediate. The ensemble of structures reveals distortion of the ligand into a {sup 1}S{sub 3} skew (or twist) boat conformation in the middle of the reaction cycle. The high resolution structures of each step in the catalytic cycle will allow for improved drug design efforts on {alpha}-GAL and other glycoside hydrolase family 27 enzymes by developing ligands that specifically target different states of the catalytic cycle. Additionally, the structures revealed a second ligand-binding site suitable for targeting by novel pharmacological chaperones.
Distribution Coefficients of Impurities in Metals
NASA Astrophysics Data System (ADS)
Pearce, J. V.
2014-04-01
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.
Danzer, Karin M; Krebs, Simon K; Wolff, Michael; Birk, Gerald; Hengerer, Bastian
2009-10-01
Lewy bodies, alpha-synuclein (alpha-syn) immunopositive intracellular deposits, are the pathological hallmark of Parkinson's disease (PD). Interestingly, Lewybody-like structures have been identified in fetal tissue grafts about one decade after transplantation into the striatum of PD patients. One possible explanation for the accelerated deposition of alpha-syn in the graft is that the aggregation of alpha-syn from the host tissue to the graft is spread by a prion disease-like mechanism. We discuss here an in vitro model which might recapitulate some aspects of disease propagation in PD. We found here that in vitro-generated alpha-syn oligomers induce transmembrane seeding of alpha-syn aggregation in a dose- and time-dependent manner. This effect was observed in primary neuronal cultures as well as in neuronal cell lines. The seeding oligomers were characterized by a distinctive lithium dodecyl sulfate-stable oligomer pattern and could be generated in a dynamic process out of pore-forming oligomers. We propose that alpha-syn oligomers form as a dynamic mixture of oligomer types with different properties and that alpha-syn oligomers can be converted into different types depending on the brain milieu conditions. Our data indicate that extracellular alpha-syn oligomers can induce intracellular alpha-syn aggregation, therefore we hypothesize that a similar mechanism might lead to alpha-syn pathology propagation.
Folate receptor {alpha} regulates cell proliferation in mouse gonadotroph {alpha}T3-1 cells
Yao, Congjun; Evans, Chheng-Orn; Stevens, Victoria L.; Owens, Timothy R.; Oyesiku, Nelson M.
2009-11-01
We have previously found that the mRNA and protein levels of the folate receptor alpha (FR{alpha}) are uniquely over-expressed in clinically human nonfunctional (NF) pituitary adenomas, but the mechanistic role of FR{alpha} has not fully been determined. We investigated the effect of FR{alpha} over-expression in the mouse gonadotroph {alpha}T3-1 cell line as a model for NF pituitary adenomas. We found that the expression and function of FR{alpha} were strongly up-regulated, by Western blotting and folic acid binding assay. Furthermore, we found a higher cell growth rate, an enhanced percentage of cells in S-phase by BrdU assay, and a higher PCNA staining. These observations indicate that over-expression of FR{alpha} promotes cell proliferation. These effects were abrogated in the same {alpha}T3-1 cells when transfected with a mutant FR{alpha} cDNA that confers a dominant-negative phenotype by inhibiting folic acid binding. Finally, by real-time quantitative PCR, we found that mRNA expression of NOTCH3 was up-regulated in FR{alpha} over-expressing cells. In summary, our data suggests that FR{alpha} regulates pituitary tumor cell proliferation and mechanistically may involve the NOTCH pathway. Potentially, this finding could be exploited to develop new, innovative molecular targeted treatment for human NF pituitary adenomas.
Calcium: Alpha-Synuclein Interactions in Alpha-Synucleinopathies
Rcom-H'cheo-Gauthier, Alexandre N.; Osborne, Samantha L.; Meedeniya, Adrian C. B.; Pountney, Dean L.
2016-01-01
Aggregation of the pre-synaptic protein, α-synuclein (α-syn), is the key etiological factor in Parkinson's disease (PD) and other alpha-synucleinopathies, such as multiple system atrophy (MSA) and Dementia with Lewy bodies (DLB). Various triggers for pathological α-syn aggregation have been elucidated, including post-translational modifications, oxidative stress, and binding of metal ions, such as calcium. Raised neuronal calcium levels in PD may occur due to mitochondrial dysfunction and/or may relate to calcium channel dysregulation or the reduced expression of the neuronal calcium buffering protein, calbindin-D28k. Recent results on human tissue and a mouse oxidative stress model show that neuronal calbindin-D28k expression excludes α-syn inclusion bodies. Previously, cell culture model studies have shown that transient increases of intracellular free Ca(II), such as by opening of the voltage-gated plasma calcium channels, could induce cytoplasmic aggregates of α-syn. Raised intracellular free calcium and oxidative stress also act cooperatively to promote α-syn aggregation. The association between raised neuronal calcium, α-syn aggregation, oxidative stress, and neurotoxicity is reviewed in the context of neurodegenerative α-syn disease and potential mechanism-based therapies. PMID:28066161
Lochter, Andre; Navre, Marc; Werb, Zena; Bissell, Mina J
1998-06-29
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.
G alpha 12 and G alpha 13 subunits define a fourth class of G protein alpha subunits.
Strathmann, M P; Simon, M I
1991-01-01
Heterotrimeric guanine nucleotide-binding regulatory proteins (G proteins) are central to the signaling processes of multicellular organisms. We have explored the diversity of the G protein subunits in mammals and found evidence for a large family of genes that encode the alpha subunits. Amino acid sequence comparisons show that the different alpha subunits fall into at least three classes. These classes have been conserved in animals separated by considerable evolutionary distances; they are present in mammals, Drosophila, and nematodes. We have now obtained cDNA clones encoding two murine alpha subunits, G alpha 12 and G alpha 13, that define a fourth class. The translation products are predicted to have molecular masses of 44 kDa and to be insensitive to ADP-ribosylation by pertussis toxin. They share 67% amino acid sequence identity with each other and less than 45% identity with other alpha subunits. Their transcripts can be detected in every tissue examined, although the relative levels of the G alpha 13 message appear somewhat variable. Images PMID:1905812
NASA Technical Reports Server (NTRS)
Whittenberger, J. D.; Krishnan, R. V.
1984-01-01
The results of a study to determine the recovery rates and work-hardening coefficients for creep from constant cross-head speed compressive tests are presented. Stressing and straining rates are computed from measured time-load curves obtained from compression testing between 1200 and 1400 K of several B2 crystal structure Fe-39.8 Al intermetallic materials and the directionally solidified eutectic alloy gamma/gamma prime alpha. These quantities are then fitted to the universal form of the Bailey-Orowan equation for creep. The recovery rates were found to be functions of nominal strain rate, stress, and temperature, while the hardening coefficients were dependent only on temperature. While the work-hardening coefficient for gamma/gamma prime - alpha was about 0.05 of the elastic modulus, the work-hardening coefficients for Fe-39.8 at. pct Al were less than 0.002 of the modulus.
Mapping High-Velocity H-alpha and Lyman-alpha Emission from Supernova 1987A
NASA Technical Reports Server (NTRS)
France, Kevin; McCray, Richard; Fransson, Claes; Larsson, Josefin; Frank, Kari A.; Burrows, David N.; Challis, Peter; Kirshner, Robert P.; Chevalier, Roger A.; Garnavich, Peter; Heng, Kevin; Lawrence, Stephen S.; Lundqvist, Peter; Smith, Nathan; Sonneborn, George
2015-01-01
We present new Hubble Space Telescope images of high-velocity H-alpha and Lyman-alpha emission in the outer debris of SN 1987A. The H-alpha images are dominated by emission from hydrogen atoms crossing the reverse shock. For the first time we observe emission from the reverse shock surface well above and below the equatorial ring, suggesting a bipolar or conical structure perpendicular to the ring plane. Using the H-alpha imaging, we measure the mass flux of hydrogen atoms crossing the reverse shock front, in the velocity intervals (-7,500 < V(sub obs) < -2,800 km/s) and (1,000 < V(sub obs) < 7,500 km/s), ?M(sub H) = 1.2 × 10(exp -3) M/ y. We also present the first Lyman-alpha imaging of the whole remnant and new Chandra X-ray observations. Comparing the spatial distribution of the Lyman-alpha and X-ray emission, we observe that the majority of the high-velocity Lyman-alpha emission originates interior to the equatorial ring. The observed Lyman-alpha/H-alpha photon ratio, R(L-alpha/H-alpha) approx. = 17, is significantly higher than the theoretically predicted ratio of approx. = 5 for neutral atoms crossing the reverse shock front. We attribute this excess to Lyman-alpha emission produced by X-ray heating of the outer debris. The spatial orientation of the Lyman-alpha and X-ray emission suggests that X-ray heating of the outer debris is the dominant Lyman-alpha production mechanism in SN 1987A at this phase in its evolution.
de Andrade, Carina A F; de Andrade, Glaucia M F; De Paula, Patricia M; De Luca, Laurival A; Menani, José V
2009-04-01
Moxonidine (alpha2-adrenoceptor/imidazoline receptor agonist) injected into the lateral ventricle induces diuresis, natriuresis and renal vasodilation. Moxonidine-induced diuresis and natriuresis depend on central imidazoline receptors, while central alpha1-adrenoceptors are involved in renal vasodilation. However, the involvement of central alpha1-adrenoceptors on diuresis and natriuresis to central moxonidine was not investigated yet. In the present study, the effects of moxonidine, alpha-methylnoradrenaline (alpha2-adrenoceptor agonist) or phenylephrine (alpha1-adrenoceptor agonist) alone or combined with previous injections of prazosin (alpha1-adrenoceptor antagonist), yohimbine or RX 821002 (alpha2-adrenoceptor antagonists) intracerebroventricularly (i.c.v.) on urinary sodium, potassium and volume were investigated. Male Holtzman rats (n = 5-18/group) with stainless steel cannula implanted into the lateral ventricle and submitted to gastric water load (10% of body weight) were used. Injections of moxonidine (20 nmol) or alpha-methylnoradrenaline (80 nmol) i.c.v. induced natriuresis (196 +/- 25 and 171 +/- 30, respectively, vs. vehicle: 101 +/- 9 microEq/2 h) and diuresis (9.0 +/- 0.4 and 12.3 +/- 1.6, respectively, vs. vehicle: 5.2 +/- 0.5 ml/2 h). Pre-treatment with prazosin (320 nmol) i.c.v. abolished the natriuresis (23 +/- 4 and 76 +/- 11 microEq/2 h, respectively) and diuresis (5 +/- 1 and 7.6 +/- 0.8 ml/2 h, respectively) produced by i.c.v. moxonidine or alpha-methylnoradrenaline. RX 821002 (320 nmol) i.c.v. abolished the natriuretic effect of alpha-methylnoradrenaline, however, yohimbine (320 nmol) did not change renal responses to moxonidine. Phenylephrine (80 nmol) i.c.v. induced natriuresis and kaliuresis that were blocked by prazosin. Therefore, the present data suggest that moxonidine and alpha-methylnoradrenaline acting on central imidazoline receptors and alpha2-adrenoceptors, respectively, activate central alpha1-adrenergic mechanisms to
[Contents and its change during storage of alpha-solanine and alpha-chaconine in potatoes].
Shindo, Tetsuya; Ushiyama, Hirofumi; Kan, Kimiko; Yasuda, Kazuo; Saito, Kazuo
2004-10-01
Contents of alpha-solanine and alpha-chaconine in native species of potato (May Queen, Danshaku and Waseshiro), and in species (Jagakids Red '90 (Red) and Jagakids Purple '90 (Purple)) on the market, and their change during storage at room temparature were investigated. alpha-Solanine and alpha-chaconine were extracted from potatoes with methanol, cleaned up by using a Sep-Pak Plus C18 cartridge, and then subjected to HPLC. The recoveries of alpha-solanine and alpha-chaconine from potatoes were both more than 96%, and the quantitation limits were both 2 microg/g. alpha-Solanine and alpha-chaconine were detected in periderm in all samples at the levels of 260-320 microg/g in May Queen,190-240 microg/g in Danshaku, 43-63 microg/g in Waseshiro, 140-200 microg/g in Red and 84-130 microg/g in Purple, respectively. alpha-Solanine and alpha-chaconine were detected in the cortex in all samples of May Queen and Danshaku at the levels of 2.7-12 microg/g and 5.8-31 microg/g, respectively. Contents of alpha-solanine and alpha-chaconine in the cortex of May Queen and Danshaku were less than 10% of those in the periderm. When potatoes were stored for 90 days at room temparature in a dark place, no marked change in the contents of alpha-solanine and alpha-chaconine was observed in any of the potato samples.
Local structure and vibrational properties of alpha-Pu, alpha-Uand the alpha-U charge density wave
Nelson, E.J.; Allen, P.G.; Blobaum, K.J.M.; Wall, W.A.; Booth, C.H.
2004-08-10
The local atomic environment and vibrational properties of atoms in monoclinic pure {alpha}-plutonium as well as orthorhombic pure a-uranium and its low-temperature charge-density-wave (CDW) modulation are examined by extended x-ray absorption fine structure spectroscopy (EXAFS). Pu L{sub III}-edge and U L{sub III}-edge EXAFS data measured at low temperatures verify the crystal structures of {alpha}-U and {alpha}-Pu samples previously determined by x-ray diffraction and neutron scattering. Debye-Waller factors from temperature-dependent EXAFS measurements are fit with a correlated Debye model. The observed Pu-Pu bond correlated Debye temperature of {theta}{sub cD}({alpha}-Pu) = 162 {+-} 5 K for the pure {alpha}-Pu phase agrees with our previous measurement of the correlated Debye temperature of the gallium-containing {alpha}{prime}-Pu phase in a mixed phase 1.9 at% Ga-doped {alpha}{prime}-Pu/{delta}-Pu alloy. The temperature dependence of the U-U nearest neighbor Debye-Waller factor exhibits a sharp discontinuity in slope near T{sub CDW} = 43 K, the transition temperature at which the charge-density wave (CDW) in {alpha}-U condenses from a soft phonon mode along the (100) direction. Our measurement of the CDW using EXAFS is the first observation of the structure of the CDW in polycrystalline {alpha}-U. The different temperature dependence of the Debye-Waller factor for T < T{sub CDW} can be modeled by the change in bond length distributions resulting from condensation of the charge density wave. For T > T{sub CDW}, the observed correlated Debye temperature of {theta}{sub cD}({alpha}-U) = 199 {+-} 3 K is in good agreement with other measurements of the Debye temperature for polycrystalline {alpha}-U. CDW structural models fit to the {alpha}-U EXAFS data support a squared CDW at the lowest temperatures, with a displacement amplitude of {var_epsilon} = 0.05 {+-} 0.02 {angstrom}.
A new alpha chain hemoglobin variant: Hb Al-Hammadi Riyadh [alpha75(EF4)Asp-->Val (alpha2)].
Burnichon, Nelly; Lacan, Philippe; Becchi, Michel; Zanella-Cleon, Isabelle; Aubry, Martine; Mowafy, Mohammed; Couprie, Nicole; Francina, Alain
2006-01-01
A new hemoglobin (Hb) variant in the heterozygous state, Hb Al-Hammadi Riyadh [codon 75 (GAC-->GTC); alpha75(EF4)Asp-->Val (alpha2)] corresponding to an A-->T transversion on the second exon of the alpha2-globin gene, is described. The variant was characterized by DNA sequencing and mass spectrometry (MS). The variant was found during a routine Hb analysis for anemia in a 16-month-old boy who lived in Riyadh, Kingdom of Saudi Arabia.
NASA Technical Reports Server (NTRS)
Calloway, R. L.; White, N. H.
1979-01-01
Experimental values of shock shapes (alpha = 0 degrees and 10 degrees) and static aerodynamic coefficients (alpha = -4 degrees to 12 degrees) for sharp and spherically blunted cones having cone half-angles of 30, 45, 60, and 70 degrees and nose bluntness ratios of 0, 0.25, and 0.50 are presented. Shock shapes were also measured at 0 degree angle of attack by using a flat-faced cylinder (90 degree cone) and a hemispherically blunted cylinder (sphere). All tests were conducted in helium (gamma = 5/3) at a free-stream Mach number of 20.3 and a unit free-stream Reynolds number of 22,400,000 per meter. Comparisons between measured values and predicted values were made by using several numerical and simple engineering methods.
Correlation analysis on alpha attenuation and nasal skin temperature
NASA Astrophysics Data System (ADS)
Nozawa, Akio; Tacano, Munecazu
2009-01-01
Some serious accidents caused by declines in arousal level, such as traffic accidents and mechanical control mistakes, have become issues of social concern. The physiological index obtained by human body measurement is expected to offer a leading tool for evaluating arousal level as an objective indicator. In this study, declines in temporal arousal levels were evaluated by nasal skin temperature. As arousal level declines, sympathetic nervous activity is decreased and blood flow in peripheral vessels is increased. Since peripheral vessels exist just under the skin on the fingers and nose, the psychophysiological state can be judged from the displacement of skin temperature caused by changing blood flow volume. Declining arousal level is expected to be observable as a temperature rise in peripheral parts of the body. The objective of this experiment was to obtain assessment criteria for judging declines in arousal level by nasal skin temperature using the alpha attenuation coefficient (AAC) of electroencephalography (EEG) as a reference benchmark. Furthermore, a psychophysical index of sleepiness was also measured using a visual analogue scale (VAS). Correlations between nasal skin temperature index and EEG index were analyzed. AAC and maximum displacement of nasal skin temperature displayed a clear negative correlation, with a correlation coefficient of -0.55.
Lockhart, Shawn R; Wu, Wei; Radke, Joshua B; Zhao, Rui; Soll, David R
2005-04-01
The majority of Candida albicans strains in nature are a/alpha and must undergo homozygosis to a/a or alpha/alpha to mate. Here we have used a mouse model for systemic infection to test the hypothesis that a/alpha strains predominate in nature because they have a competitive advantage over a/a and alpha/alpha offspring in colonizing hosts. Single-strain injection experiments revealed that a/alpha strains were far more virulent than either their a/a or alpha/alpha offspring. When equal numbers of parent a/alpha and offspring a/a or alpha/alpha cells were co-injected, a/alpha always exhibited a competitive advantage at the time of extreme host morbidity or death. When equal numbers of an engineered a/a/alpha2 strain and its isogenic a/a parent strain were co-injected, the a/a/alpha2 strain exhibited a competitive advantage at the time of host morbidity or death, suggesting that the genotype of the mating-type (MTL) locus, not associated genes on chromosome 5, provides a competitive advantage. We therefore propose that heterozygosity at the MTL locus not only represses white-opaque switching and genes involved in the mating process, but also affects virulence, providing a competitive advantage to the a/alpha genotype that conserves the mating system of C. albicans in nature.
Wu, L; Gaskins, C; Zhou, K; Firtel, R A; Devreotes, P N
1994-01-01
GTP-binding protein (G protein)-mediated signal transduction pathways play essential roles during the aggregation and differentiation process of Dictyostelium. In addition to the five known G protein alpha-subunit genes, we recently identified three novel alpha-subunit genes, G alpha 6, G alpha 7, and G alpha 8, using the polymerase chain reaction technique. We present here a more complete analysis of G alpha 7 and G alpha 8. The cDNAs of these two genes were cloned, and their complete nucleotide sequences were determined. Sequence analyses indicate that G alpha 8 possesses some unusual features. It lacks the "TCATDT" motif, a sequence of amino acids highly conserved among G alpha subunits, and has an additional 50 amino acids at its C-terminus consisting of long stretches of asparagine. Moreover, G alpha 8 is unusually resistant to protease digestion, which may indicate a slow GTP hydrolysis rate. The possible functions of these alpha-subunits were assessed by generating mutants lacking G alpha 7 or G alpha 8 by gene targeting through homologous recombination and by overexpressing G alpha 7 or G alpha 8 protein. Overexpression of G alpha 7 resulted in abnormal morphogenesis starting at the slug stage, whereas analysis of the other strains failed to reveal any obvious growth or developmental defects under either normal or stressful conditions. The implications of these results are discussed. Images PMID:7949425
Lucid dreaming and alpha activity: a preliminary report.
Ogilvie, R D; Hunt, H T; Tyson, P D; Lucescu, M L; Jeakins, D B
1982-12-01
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.
Lyman alpha emission in starburst galaxies
NASA Astrophysics Data System (ADS)
Kunth, Daniel
1999-07-01
We propose to perform a deep study of Ly-alpha emission and destruction in 3 star-forming galaxies. These objects have been already observed with the GHRS and exhibit a variety of situations, with Ly-alpha showing P Cyg profiles, secondary emissions or even a deep damped absorption line with no emission. They also span a range of intrinsic properties: IZW18 is a gas-rich, metal deficient dust free dwarf galaxy, Haro 2 has a simple morphology while IRAS 08339+6517 is a luminous IRAS starburst galaxy with more dust and complex Ly- alpha profile. The use of STIS will allow for the first time to study the geometrical/kinematical configuration of the ionized and neutral gas across the galaxies nuclear regions and pin point the effects of porosity and the kinematical structure of the ISM, that may play the key roles {in addition to dust} in the detectability of the line. This study will have important impact for cosmology since Ly-alpha emitters are nowaday found at high-re dshift. We strongly emphasize that since Ly-alpha is primarely a diagnostic of the ISM, a full understanding of how the ISM and Ly-alpha are related is a necessary step before we can hope to correlate Ly-alpha to the cosmic star-formation rate. Our results will be interpreted against the model of superbubble evolution developed with G. Tenorio Tagle.
Lyman Alpha Spicule Observatory (LASO)
NASA Astrophysics Data System (ADS)
Chamberlin, P. C.; Allred, J. C.; Airapetian, V.; Gong, Q.; Mcintosh, S. W.; De Pontieu, B.; Fontenla, J. M.
2011-12-01
The Lyman Alpha Spicule Observatory (LASO) sounding rocket will observe small-scale 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 66mÅ (33mÅ pixels) across a broad 20Å spectral window. This spectral window contains three strong chromospheric and transition region emissions and is centered on the strong Hydrogen Lyman-α emission at 1216Å. 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.
Lyman Alpha Spicule Observatory (LASO)
NASA Astrophysics Data System (ADS)
Chamberlin, Phillip C.; Allred, J.; Airapetian, V.; Gong, Q.; Fontenla, J.; McIntosh, S.; de Pontieu, B.
2011-05-01
The Lyman Alpha Spicule Observatory (LASO) sounding rocket will observe small-scale eruptive events called "Rapid Blue-shifted Events” (RBEs), the on-disk equivalent of Type-II spicules, and extend observations that explore their role in the solar coronal heating problem. 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 66mÅ (33mÅ pixels) across a broad 20Å spectral window. This spectral window contains three strong chromospheric and transition region emissions and is centered on the strong Hydrogen Lyman-α emission at 1216Å. 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.
Lyman Alpha Spicule Observatory (LASO)
NASA Technical Reports Server (NTRS)
Chamberlin, Phillip C.
2011-01-01
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.
Diabetes and Alpha Lipoic Acid
Golbidi, Saeid; Badran, Mohammad; Laher, Ismail
2011-01-01
Diabetes mellitus is a multi-faceted metabolic disorder where there is increased oxidative stress that contributes to the pathogenesis of this debilitating disease. This has prompted several investigations into the use of antioxidants as a complementary therapeutic approach. Alpha lipoic acid, a naturally occurring dithiol compound which plays an essential role in mitochondrial bioenergetic reactions, has gained considerable attention as an antioxidant for use in managing diabetic complications. Lipoic acid quenches reactive oxygen species, chelates metal ions, and reduces the oxidized forms of other antioxidants such as vitamin C, vitamin E, and glutathione. It also boosts antioxidant defense system through Nrf-2-mediated antioxidant gene expression and by modulation of peroxisome proliferator activated receptors-regulated genes. ALA inhibits nuclear factor kappa B and activates AMPK in skeletal muscles, which in turn have a plethora of metabolic consequences. These diverse actions suggest that lipoic acid acts by multiple mechanisms, many of which have only been uncovered recently. In this review we briefly summarize the known biochemical properties of lipoic acid and then discussed the oxidative mechanisms implicated in diabetic complications and the mechanisms by which lipoic acid may ameliorate these reactions. The findings of some of the clinical trials in which lipoic acid administration has been tested in diabetic patients during the last 10 years are summarized. It appears that the clearest benefit of lipoic acid supplementation is in patients with diabetic neuropathy. PMID:22125537
Targeted alpha therapy: part I.
Elgqvist, Jorgen
2011-07-01
The possibility of pinpointing biological targets, and thereby potentially targeting and eradicating small tumors or even single cancer cells, is a tantalizing concept that has been discussed since the magic-bullet concept was first presented by Paul Erlich in the beginning of the 20th century in connection with his work on tissue staining for histological examinations and the work by Kohler and Milstein on antibody production published in 1975. This concept now seems feasible through the use of highly specific targeting constructs, chemical labeling of radioactive substances to these targeting constructs that results in high specific activities, radioimmunocomplexes with good stability even after injection, and the use of radionuclides emitting alpha( α)-particles having exceedingly high ionizing density and, therefore, a high probability of killing cells along its track in tissue. The short range of the emitted α-particles makes them even more interesting by minimizing unwanted irradiation of normal tissue surrounding the targeted cancer cells of interest, assuming high specificity of the targeting construct and good stability of the chemical bonds between the targeting construct and the α-particle emitter. Targeted Alpha Therapy (TAT), in which an α-particle emitting radionuclide is specifically directed to the biological target, is gaining more attention as new targets, targeting constructs, chemical labeling techniques, and α-particle emitters are, respectively, identified, constructed, developed, and made available. Results and improvements are now being published at an increasing rate and the number of conceivable applications is expanding, especially in the field of cancer treatment. Therefore, it is of utmost importance to provide an overview of the overall progress in the research field of TAT on a regular basis. However, problems such as limited or delayed diffusion of the α-radioimmunocomplex and inhomogeneous activity distributions in the
Scalable encryption using alpha rooting
NASA Astrophysics Data System (ADS)
Wharton, Eric J.; Panetta, Karen A.; Agaian, Sos S.
2008-04-01
Full and partial encryption methods are important for subscription based content providers, such as internet and cable TV pay channels. Providers need to be able to protect their products while at the same time being able to provide demonstrations to attract new customers without giving away the full value of the content. If an algorithm were introduced which could provide any level of full or partial encryption in a fast and cost effective manner, the applications to real-time commercial implementation would be numerous. In this paper, we present a novel application of alpha rooting, using it to achieve fast and straightforward scalable encryption with a single algorithm. We further present use of the measure of enhancement, the Logarithmic AME, to select optimal parameters for the partial encryption. When parameters are selected using the measure, the output image achieves a balance between protecting the important data in the image while still containing a good overall representation of the image. We will show results for this encryption method on a number of images, using histograms to evaluate the effectiveness of the encryption.
NASA Astrophysics Data System (ADS)
Gilmore, Mark; Hsu, Scott
2015-11-01
The goal of the Plasma Liner eXperiment PLX-alpha at Los Alamos National Laboratory is to establish the viability of creating a spherically imploding plasma liner for MIF and HED applications, using a spherical array of supersonic plasma jets launched by innovative contoured-gap coaxial plasma guns. PLX- α experiments will focus in particular on establishing the ram pressure and uniformity scalings of partial and fully spherical plasma liners. In order to characterize these parameters experimentally, a suite of diagnostics is planned, including multi-camera fast imaging, a 16-channel visible interferometer (upgraded from 8 channels) with reconfigurable, fiber-coupled front end, and visible and VUV high-resolution and survey spectroscopy. Tomographic reconstruction and data fusion techniques will be used in conjunction with interferometry, imaging, and synthetic diagnostics from modeling to characterize liner uniformity in 3D. Diagnostic and data analysis design, implementation, and status will be presented. Supported by the Advanced Research Projects Agency - Energy - U.S. Department of Energy.
Shankar, Manoharan; Priyadharshini, Ramachandran; Gunasekaran, Paramasamy
2009-08-01
An image analysis-based method for high throughput screening of an alpha-amylase mutant library using chromogenic assays was developed. Assays were performed in microplates and high resolution images of the assay plates were read using the Virtual Microplate Reader (VMR) script to quantify the concentration of the chromogen. This method is fast and sensitive in quantifying 0.025-0.3 mg starch/ml as well as 0.05-0.75 mg glucose/ml. It was also an effective screening method for improved alpha-amylase activity with a coefficient of variance of 18%.
SUMOylation of ROR{alpha} potentiates transcriptional activation function
Hwang, Eun Ju; Lee, Ji Min; Jeong, Jiyeong; Park, Joo Hyeon; Yang, Young; Lim, Jong-Seok; Kim, Jung Hwa; Baek, Sung Hee; Kim, Keun Il
2009-01-16
SUMOylation regulates a variety of cellular processes, including control of transcriptional activities of nuclear receptors. Here, we present SUMOylation of orphan nuclear receptor, ROR{alpha} by both SUMO-1 and SUMO-2. SUMOylation of ROR{alpha} occurred on the 240th lysine residue at the hinge region of human protein. PIAS family members, PIASx{alpha}, PIAS3, and PIASy, increased SUMOylation of ROR{alpha}, whereas SENP2 specifically removed SUMO from ROR{alpha}. SUMOylation-defective mutant form of ROR{alpha} exhibited decreased transcriptional activity on ROR{alpha}-responsive promoters indicating that SUMOylation may positively regulate transcriptional function of ROR{alpha}.
Fu, Y.; Cao, Y.; Hertzberg, K.M.; Grieninger, G.
1995-11-01
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.
Smit, Christine M; Wright, Margaret J; Hansell, Narelle K; Geffen, Gina M; Martin, Nicholas G
2006-08-01
To further clarify the mode of genetic transmission on individual alpha frequency (IAF) and alpha power, the extent to which individual differences in these alpha indices are influenced by genetic factors were examined in a large sample of adolescent twins (237 MZ, 282 DZ pairs; aged 16). EEG was measured at rest (eyes closed) from the right occipital site, and a second EEG recording for 50 twin pairs obtained approximately 3 months after the initial collection, enabled an estimation of measurement error. Analyses confirmed a strong genetic influence on both IAF (h(2)=0.81) and alpha power (h(2)=0.82), and there was little support for non-additive genetic (dominance) variance. A small but significant negative correlation (-0.18) was found between IAF and alpha power, but genetic influences on IAF and alpha power were largely independent. All non-genetic variance was due to unreliability, with no significant variance attributed to unique environmental factors. Relationships between the alpha and IQ indices were also explored but were generally either non-significant or very low. The findings confirm the high heritability for both IAF and alpha power, they further suggest that the mode of genetic transmission is due to additive genetic factors, that genetic influences on the underlying neural mechanisms of alpha frequency and power are largely specific, and that individual differences in alpha activity are influenced little by developmental plasticity and individual experiences.
Collagen alpha5 and alpha2(IV) chain coexpression: analysis of skin biopsies of Alport patients.
Patey-Mariaud de Serre, N; Garfa, M; Bessiéres, B; Noël, L H; Knebelmann, B
2007-08-01
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.
Variable displacement alpha-type Stirling engine
NASA Astrophysics Data System (ADS)
Homutescu, V. M.; Bălănescu, D. T.; Panaite, C. E.; Atanasiu, M. V.
2016-08-01
The basic design and construction of an alpha-type Stirling engine with on load variable displacement is presented. The variable displacement is obtained through a planar quadrilateral linkage with one on load movable ground link. The physico-mathematical model used for analyzing the variable displacement alpha-type Stirling engine behavior is an isothermal model that takes into account the real movement of the pistons. Performances and power adjustment capabilities of such alpha-type Stirling engine are calculated and analyzed. An exemplification through the use of the numerical simulation was performed in this regard.
Palacios, Francisco; Vicario, Javier; Maliszewska, Agnieszka; Aparicio, Domitila
2007-03-30
An efficient synthesis of alpha,beta-unsaturated imines derived from alpha-aminophosphonates is achieved through aza-Wittig reaction of P-trimethyl phosphazenes with beta,gamma-unsaturated alpha-ketophosphonates. Selective 1,2-reduction of such 1-azadienes affords beta,gamma-unsaturated alpha-aminophosphonates, phosphorylated analogs of vinylglycines, which are hydrogenated to yield saturated alpha-aminophosphonate derivatives.
Calculation and application of combined diffusion coefficients in thermal plasmas
NASA Astrophysics Data System (ADS)
Murphy, Anthony B.
2014-03-01
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.
Piezo-optic coefficients of CaWO4 crystals
NASA Astrophysics Data System (ADS)
Mytsyk, B. G.; Kost', Ya. P.; Demyanyshyn, N. M.; Andrushchak, A. S.; Solskii, I. M.
2015-01-01
All components of the piezo-optic coefficient matrix of calcium tungstate crystals, belonging to the 4/ m symmetry class, are determined. The reliability of the piezo-optic effect measurements in CaWO4 crystals is achieved by determining each piezo-optic coefficient from several experimental geometries and is also based on the correlation of the absolute piezo-electric coefficients and the path-difference coefficients. The rotation-shear diagonal coefficients π44 and π66 and three principal piezo-optic coefficients π11, π13, and π31 are refined by the polarization-optical method. It is confirmed that both the interferometric and polarization-optical methods should be used to study the piezo-optic effect with high accuracy. The results show that calcium tungstate is a promising material for acousto-optical and photoelastic modulation.
Low-reflection-coefficient liquid interfaces for system characterization.
Hall, T J; Madsen, E L; Dong, F; Medina, I R; Frank, G R
2001-07-01
The use of liquid brominated hydrocarbons to form a planar reflecting interface with water is described. Gravity-based planar reflecting surfaces with known reflection coefficients can be used in system characterization for quantitative ultrasonics, and a set of surfaces with a range of reflection coefficients allows calibration of the output power and receiver gain of ultrasonic imaging systems. The substances reported here are immiscible in water and form interfaces with water, resulting in a broad range of acoustic reflection coefficients. Reflection coefficients were measured at temperatures from 18-24 degrees C for "pure" substances and for mixtures of two brominated hydrocarbons. Results show that reflection coefficients are weakly dependent on temperature and that, at a specific temperature, a significant range of arbitrarily small reflection coefficients is available, in the case of the mixtures, by the appropriate choice of weight-percents of the two brominated hydrocarbons.
Osmotic second virial cross coefficients for star and linear polystyrenes
Striolo, Alberto; Prausnitz, John M. [Chemical Engineering Department, University of California, Berkeley, Berkeley, California 94720
2000-08-15
Experimental osmotic second virial cross coefficients are reported for linear and 8-arm star polystyrenes in three solvents: toluene, cyclohexane, and methylcyclohexane. The osmotic second virial cross coefficient for 8-arm star and linear polystyrene is always positive and within the osmotic second virial coefficients measured for the single polymers. The positive cross coefficient indicates net repulsion between the two different polymers in dilute solution. The extent of repulsion is greatest in toluene and least in cyclohexane. To relate the macroscopic second virial coefficient to microscopic interactions, the potential of mean force between linear and 6-arm star polymers was computed by molecular simulation. The interaction between nonbonded polymer segments is given by a square-well potential. Well width was set equal to one half of the segment diameter. Different solvent conditions were investigated by using different well depths. Potentials of mean force were then used to compute the osmotic second virial cross coefficients. (c) 2000 American Institute of Physics.
ANALYTIC FORMS OF THE PERPENDICULAR DIFFUSION COEFFICIENT IN NRMHD TURBULENCE
Shalchi, A.
2015-02-01
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.
Personal dose-equivalent conversion coefficients for 1252 radionuclides.
Otto, Thomas
2016-01-01
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.
Yarmukhamedov, R.; Baye, D.
2011-08-15
Explicit relations between the effective-range expansion and the nuclear vertex constant or asymptotic normalization coefficient (ANC) for the virtual decay B{yields}A+a are derived for an arbitrary orbital momentum together with the corresponding location condition for the (A+a) bound-state energy. They are valid both for the charged case and for the neutral case. Combining these relations with the standard effective-range function up to order six makes it possible to reduce to two the number of free effective-range parameters if an ANC value is known from experiment. Values for the scattering length, effective range, and form parameter are determined in this way for the {sup 16}O+p, {alpha}+t, and {alpha}+{sup 3}He collisions in partial waves where a bound state exists by using available ANCs deduced from experiments. The resulting effective-range expansions for these collisions are valid up to energies larger than 5 MeV.
PAC91 - PROPERTIES AND COEFFICIENTS 1991
NASA Technical Reports Server (NTRS)
Mcbride, B. J.
1994-01-01
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
Aerosol Angstrom Absorption Coefficient Comparisons during MILAGRO.
NASA Astrophysics Data System (ADS)
Marley, N. A.; Marchany-Rivera, A.; Kelley, K. L.; Mangu, A.; Gaffney, J. S.
2007-12-01
aerosol Angstrom absorption exponents by linear regression over the entire UV-visible spectral range. These results are compared to results obtained from the absorbance measurements obtained in the field. The differences in calculated Angstrom absorption exponents between the field and laboratory measurements are attributed partly to the differences in time resolution of the sample collection resulting in heavier particle pileup on the filter surface of the 12-hour samples. Some differences in calculated results can also be attributed to the presence of narrow band absorbers below 400 nm that do not fall in the wavelengths covered by the 7 wavelengths of the aethalometer. 1. Marley, N.A., J.S. Gaffney, J.C. Baird, C.A. Blazer, P.J. Drayton, and J.E. Frederick, "The determination of scattering and absorption coefficients of size-fractionated aerosols for radiative transfer calculations." Aerosol Sci. Technol., 34, 535-549, (2001). This work was conducted as part of the Department of Energy's Atmospheric Science Program as part of the Megacity Aerosol Experiment - Mexico City during MILAGRO. This research was supported by the Office of Science (BER), U.S. Department of Energy Grant No. DE-FG02-07ER64329. We also wish to thank Mexican Scientists and students for their assistance from the Instituto Mexicano de Petroleo (IMP) and CENICA.
Spatial Correlation Coefficient Images for Ultrasonic Detection (Preprint)
2006-07-01
for image formation and detection based on the similarity of adjacent signals. Signal similarity is quantified in terms of the correlation coefficient calculated...between A-scans digitized at adjacent measurement positions. Correlation coefficient images are introduced for visualizing the similarity...beam field with the defect. Correlation coefficient and C-scan images are shown to demonstrate flat-bottom-hole detection in a stainless steel annular
Lock Culvert Valve Loss Coefficients. Hydraulic Laboratory Investigation.
1981-09-01
expansion on valve loss coefficients.,_ DO FORM M4 EDITION OF INOV 6S IS OBSOLETE Unclassified SECURITY CLASSIFICATION OF THIS PAGE (tan Data Entered) Ot...v 1 /2g where K = valve loss coefficient v AE = energy loss of the valve, ft V = average velocity in the culvert upstream from the valve, fps g...22g , to the head loss the total energy loss at the valve section, AE , was determined. The valve loss coefficient was then computed using Equation I
DCFPAK: Dose coefficient data file package for Sandia National Laboratory
Eckerman, K.F.; Leggett, R.W.
1996-07-31
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.
Scanning measurement of Seebeck coefficient of a heated sample
Snyder, G. Jeffrey; Iwanaga, Shiho
2016-04-19
A novel scanning Seebeck coefficient measurement technique is disclosed utilizing a cold scanning thermocouple probe tip on heated bulk and thin film samples. The system measures variations in the Seebeck coefficient within the samples. The apparatus may be used for two dimensional mapping of the Seebeck coefficient on the bulk and thin film samples. This technique can be utilized for detection of defective regions, as well as phase separations in the sub-mm range of various thermoelectric materials.
Distribution coefficients of rare earth ions in cubic zirconium dioxide
NASA Astrophysics Data System (ADS)
Romer, H.; Luther, K.-D.; Assmus, W.
1994-08-01
Cubic zirconium dioxide crystals are grown with the skull melting technique. The effective distribution coefficients for Nd(exp 3+), Sm(exp 3+) and Er(sup 3+) as dopants are determined experimentally as a function of the crystal growth velocity. With the Burton-Prim-Slichter theory, the equilibrium distribution coefficients can be calculated. The distribution coefficients of all other trivalent rare earth ions can be estimated by applying the correlation towards the ionic radii.
Oxygen binding by alpha(Fe2+)2beta(Ni2+)2 hemoglobin crystals.
Bruno, S.; Bettati, S.; Manfredini, M.; Mozzarelli, A.; Bolognesi, M.; Deriu, D.; Rosano, C.; Tsuneshige, A.; Yonetani, T.; Henry, E. R.
2000-01-01
Oxygen binding by hemoglobin fixed in the T state either by crystallization or by encapsulation in silica gels is apparently noncooperative. However, cooperativity might be masked by different oxygen affinities of alpha and beta subunits. Metal hybrid hemoglobins, where the noniron metal does not bind oxygen, provide the opportunity to determine the oxygen affinities of alpha and beta hemes separately. Previous studies have characterized the oxygen binding by alpha(Ni2+)2beta(Fe2+)2 crystals. Here, we have determined the three-dimensional (3D) structure and oxygen binding of alpha(Fe2+)2beta(Ni2+)2 crystals grown from polyethylene glycol solutions. Polarized absorption spectra were recorded at different oxygen pressures with light polarized parallel either to the b or c crystal axis by single crystal microspectrophotometry. The oxygen pressures at 50% saturation (p50s) are 95 +/- 3 and 87 +/- 4 Torr along the b and c crystal axes, respectively, and the corresponding Hill coefficients are 0.96 +/- 0.06 and 0.90 +/- 0.03. Analysis of the binding curves, taking into account the different projections of the alpha hemes along the optical directions, indicates that the oxygen affinity of alpha1 hemes is 1.3-fold lower than alpha2 hemes. Inspection of the 3D structure suggests that this inequivalence may arise from packing interactions of the Hb tetramer within the monoclinic crystal lattice. A similar inequivalence was found for the beta subunits of alpha(Ni2+)2beta(Fe2+)2 crystals. The average oxygen affinity of the alpha subunits (p50 = 91 Torr) is about 1.2-fold higher than the beta subunits (p50 = 110 Torr). In the absence of cooperativity, this heterogeneity yields an oxygen binding curve of Hb A with a Hill coefficient of 0.999. Since the binding curves of Hb A crystals exhibit a Hill coefficient very close to unity, these findings indicate that oxygen binding by T-state hemoglobin is noncooperative, in keeping with the Monod, Wyman, and Changeux model. PMID
Oxygen binding by alpha(Fe2+)2beta(Ni2+)2 hemoglobin crystals.
Bruno, S; Bettati, S; Manfredini, M; Mozzarelli, A; Bolognesi, M; Deriu, D; Rosano, C; Tsuneshige, A; Yonetani, T; Henry, E R
2000-04-01
Oxygen binding by hemoglobin fixed in the T state either by crystallization or by encapsulation in silica gels is apparently noncooperative. However, cooperativity might be masked by different oxygen affinities of alpha and beta subunits. Metal hybrid hemoglobins, where the noniron metal does not bind oxygen, provide the opportunity to determine the oxygen affinities of alpha and beta hemes separately. Previous studies have characterized the oxygen binding by alpha(Ni2+)2beta(Fe2+)2 crystals. Here, we have determined the three-dimensional (3D) structure and oxygen binding of alpha(Fe2+)2beta(Ni2+)2 crystals grown from polyethylene glycol solutions. Polarized absorption spectra were recorded at different oxygen pressures with light polarized parallel either to the b or c crystal axis by single crystal microspectrophotometry. The oxygen pressures at 50% saturation (p50s) are 95 +/- 3 and 87 +/- 4 Torr along the b and c crystal axes, respectively, and the corresponding Hill coefficients are 0.96 +/- 0.06 and 0.90 +/- 0.03. Analysis of the binding curves, taking into account the different projections of the alpha hemes along the optical directions, indicates that the oxygen affinity of alpha1 hemes is 1.3-fold lower than alpha2 hemes. Inspection of the 3D structure suggests that this inequivalence may arise from packing interactions of the Hb tetramer within the monoclinic crystal lattice. A similar inequivalence was found for the beta subunits of alpha(Ni2+)2beta(Fe2+)2 crystals. The average oxygen affinity of the alpha subunits (p50 = 91 Torr) is about 1.2-fold higher than the beta subunits (p50 = 110 Torr). In the absence of cooperativity, this heterogeneity yields an oxygen binding curve of Hb A with a Hill coefficient of 0.999. Since the binding curves of Hb A crystals exhibit a Hill coefficient very close to unity, these findings indicate that oxygen binding by T-state hemoglobin is noncooperative, in keeping with the Monod, Wyman, and Changeux model.
Discharge coefficients of impingement and film cooling holes
NASA Astrophysics Data System (ADS)
Chu, T.; Brown, A.; Garret, S.
1985-03-01
In this article measurements of fluid flow through impingement and film cooling holes for typical turbine blade cooling systems are presented. The purpose of the measurements was to determine hole discharge coefficients over a range of Reynolds numbers from 5,000 to 30,000 and to observe in this range the dependence of discharge coefficient on Reynolds number. The effect of hole geometry, that is, sharp edged inlet or corner radius inlet, on discharge coefficients is also measured. Correlations relating discharge coefficients to Reynolds number, corner radius to hole diameter ratio, and blowing parameter are suggested.
Coefficients of convergent multiple Walsh-Paley series
Plotnikov, Mikhail G
2012-09-30
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.
Diffusion coefficient of three-dimensional Yukawa liquids
Dzhumagulova, K. N.; Ramazanov, T. S.; Masheeva, R. U.
2013-11-15
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.
Friction coefficient estimation using an unscented Kalman filter
NASA Astrophysics Data System (ADS)
Zhao, Yunshi; Liang, Bo; Iwnicki, Simon
2014-05-01
The friction coefficient between a railway wheel and rail surface is a crucial factor in maintaining high acceleration and braking performance of railway vehicles; therefore, monitoring this friction coefficient is important. Due to the difficulty in directly measuring the friction coefficient, the creep force or creepage, indirect methods using state observers are used more frequently. This paper presents an approach using an unscented kalman filter to estimate the creep force and creepage and the friction coefficient from traction motor behaviours. A scaled roller rig is designed and a series of experiments is carried out to evaluate the estimator performance.
Estimating varying coefficients for partial differential equation models.
Zhang, Xinyu; Cao, Jiguo; Carroll, Raymond J
2017-01-11
Partial differential equations (PDEs) are used to model complex dynamical systems in multiple dimensions, and their parameters often have important scientific interpretations. In some applications, PDE parameters are not constant but can change depending on the values of covariates, a feature that we call varying coefficients. We propose a parameter cascading method to estimate varying coefficients in PDE models from noisy data. Our estimates of the varying coefficients are shown to be consistent and asymptotically normally distributed. The performance of our method is evaluated by a simulation study and by an empirical study estimating three varying coefficients in a PDE model arising from LIDAR data.
Sedimentation of multicomponent viruses: evaluation of sedimentation coefficient ratios.
Larcom, L L; Barnett, O W
1978-01-01
Ratios of the sedimentation coefficients for alfalfa mosaic virus components are shown to be independent of the virus concentration and the density of the solvent. Different numbers of components are observed in solvents of different density. This implies that in sedimentation velocity experiments an estimate of the number of components of a multicomponent virus should involve centrifugation in solvents of different density. For some viruses, estimates of the sedimentation coefficients of individual components can be obtained from the coefficient ratios observed in unfractionated solutions and the sedimentation coefficient of the most easily purified component.
Kinetic theory of the interdiffusion coefficient in dense plasmas
Boercker, D.B.
1986-08-01
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.
Effect of kinetic boundary condition on the thermal transpiration coefficient
NASA Astrophysics Data System (ADS)
Sugimoto, Hiroshi; Amakawa, Kenjiro
2014-12-01
The effect of kinetic boundary condition on the free molecular thermal transpiration coefficient γ 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 γ depends much on the velocity dependency of the accommodation coefficient. The experimental result, γ < 0.5, can be reproduced if the grazing molecules reflect diffusely. This makes a sharp contrast with the previous works that γ =0.5 for the velocity independent accommodation coefficient.
Methods of Calculation of a Friction Coefficient: Application to Nanotubes
NASA Astrophysics Data System (ADS)
Servantie, J.; Gaspard, P.
2003-10-01
In this Letter we develop theoretical and numerical methods to calculate the dynamic friction coefficient. The theoretical method is based on an adiabatic approximation which allows us to express the dynamic friction coefficient in terms of the time integral of the autocorrelation function of the force between both sliding objects. The motion of the objects and the autocorrelation function can be numerically calculated by molecular-dynamics simulations. We have successfully applied these methods to the evaluation of the dynamic friction coefficient of the relative motion of two concentric carbon nanotubes. The dynamic friction coefficient is shown to increase with the temperature.
Liu, Cong; Kolarik, Barbara; Gunnarsen, Lars; Zhang, Yinping
2015-10-20
Polychlorinated biphenyls (PCBs) have been found to be persistent in the environment and possibly harmful. Many buildings are characterized with high PCB concentrations. Knowledge about partitioning between primary sources and building materials is critical for exposure assessment and practical remediation of PCB contamination. This study develops a C-depth method to determine diffusion coefficient (D) and partition coefficient (K), two key parameters governing the partitioning process. For concrete, a primary material studied here, relative standard deviations of results among five data sets are 5%-22% for K and 42-66% for D. Compared with existing methods, C-depth method overcomes the inability to obtain unique estimation for nonlinear regression and does not require assumed correlations for D and K among congeners. Comparison with a more sophisticated two-term approach implies significant uncertainty for D, and smaller uncertainty for K. However, considering uncertainties associated with sampling and chemical analysis, and impact of environmental factors, the results are acceptable for engineering applications. This was supported by good agreement between model prediction and measurement. Sensitivity analysis indicated that effective diffusion distance, contacting time of materials with primary sources, and depth of measured concentrations are critical for determining D, and PCB concentration in primary sources is critical for K.
Analytical aerodynamic model of a high alpha research vehicle wind-tunnel model
NASA Technical Reports Server (NTRS)
Cao, Jichang; Garrett, Frederick, Jr.; Hoffman, Eric; Stalford, Harold
1990-01-01
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.
Photoluminescence detection of alpha particle using DAM-ADC nuclear detector
NASA Astrophysics Data System (ADS)
Abdalla, Ayman M.; Harraz, Farid A.; Ali, Atif M.; Al-Sayari, S. A.; Al-Hajry, A.
2016-09-01
The photoluminescence (PL) and UV-vis spectral analysis of DAM-ADC (diallyl maleate: DAM, polyallyl diglycol carbonate: ADC) nuclear detector are demonstrated for the first time. The DAM-ADC surfaces were exposed to thin 241Am disk source that emits alpha particles with activity 333 kBq. It is found that the track density of the irradiated samples remarkably influences the PL characteristics of the DAM-ADC detector. The spectral peak heights and the integrated intensities under the peaks exhibit linear correlations with correlation coefficient R2=0.9636 and 0.9806, respectively for different alpha particle fluences ranging from 8.16-40.82×107 particles/cm2. Additionally, a correlation coefficient R2=0.9734 was achieved for the UV-vis spectral analysis. The linear fitting functions, along with the corresponding fitting parameters were evaluated in each case. Both the PL and the UV-vis data of the irradiated DAM-ADC samples showed considerable spectral differences, and hence they would be used to offer sensitive approaches for alpha particle detection.
Iida, T; Nishida, S; Chang, F C; Niwa, T; Goto, J; Nambara, T
1993-04-01
Syntheses by a new procedure of the known 3 alpha,6 alpha,7 beta- and 3 alpha,6 beta,7 beta-trihydroxy-5 alpha-cholanoic acids, and of the once-reported analog 3 alpha,6 alpha,7 beta,12 alpha-, as well as the new 3 alpha,6 beta,7 beta,12 alpha-tetrahydroxy-5 alpha-cholanoic acids, are described. Key intermediates of the syntheses are the 6-oxo-7 beta-ols of the respective 5 alpha-cholanoic acids (and their methyl esters) prepared by allomerization at C-5 of appropriate 6-bromo-7-oxo derivatives of the corresponding 5 beta-acids. Successful reduction of the 6,7-ketols to the desired products depended on the proper choice of reagents, either Zn(BH4)2 or Li/NH3/MeOH.
Alpha-1 Antitrypsin Deficiency (Inherited Emphysema)
... lung disease, • Physical exam, • Breathing tests and X-rays and • Oxygen levels. Two special blood tests determine the diagnosis of Alpha-1 Antitrypsin Deficiency. The first test measures the ...
Nuclear diagnostic for fast alpha particles
Grisham, L.R.; Post, D.E. Jr.; Dawson, J.M.
1983-11-23
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.
Thorium isotopic analysis by alpha spectrometry.
Gingell, T
2001-01-01
The technique of alpha spectrometry is used to detect alpha particles and to determine their energy. In this way the technique is able to provide simultaneously quantitative information (i.e. the activity) and qualitative information (the identity) on any radionuclide that emits an alpha particle. The longer-lived naturally occurring isotopes of thorium are all alpha emitters so the technique can be used to quantify them directly and this is extremely important if radiation doses due to intakes of these isotopes into the body are to be accurately assessed. The principle of the technique is discussed, its advantages and disadvantages, and the instrumentation that is commonly used today. The need for radiochemical separation is discussed and illustrated by reference to analysis procedures in current use for thorium isotopic analysis. Practical issues such as detection limits, quality control procedures. sample throughput and cost will be covered.
Radioimmunotherapy with alpha-particle emitting radionuclides.
Zalutsky, M R; Pozzi, O R
2004-12-01
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.
Radioimmunotherapy with alpha-emitting nuclides.
McDevitt, M R; Sgouros, G; Finn, R D; Humm, J L; Jurcic, J G; Larson, S M; Scheinberg, D A
1998-09-01
This review discusses the application of alpha particle-emitting radionuclides in targeted radioimmunotherapy. It will outline the production and chemistry of astatine-211, bismuth-212, lead-212, actinium-225, bismuth-213, fermium-255, radium-223 and terbium-149, which at present are the most promising alpha-emitting isotopes available for human clinical use. The selective cytotoxicity offered by alpha particle-emitting radioimmunoconstructs is due to the high linear energy transfer and short particle path length of these radionuclides. Based upon the pharmacokinetics of alpha particle-emitting radioimmunoconstructs, both stochastic and conventional dosimetric methodology is discussed, as is the preclinical and initial clinical use of these radionuclides conjugated to monoclonal antibodies for the treatment of human neoplasia.
Genetics Home Reference: 5-alpha reductase deficiency
... About half of these individuals adopt a male gender role in adolescence or early adulthood. Related Information ... 1730-5. Citation on PubMed Cohen-Kettenis PT. Gender change in 46,XY persons with 5alpha-reductase- ...
Alpha Coincidence Spectroscopy studied with GEANT4
Dion, Michael P.; Miller, Brian W.; Tatishvili, Gocha; Warren, Glen A.
2013-11-02
Abstract The high-energy side of peaks in alpha spectra, e.g. 241Am, as measured with a silicon detector has structure caused mainly by alpha-conversion electron and to some extent alphagamma coincidences. We compare GEANT4 simulation results to 241Am alpha spectroscopy measurements with a passivated implanted planar silicon detector. A large discrepancy between the measurements and simulations suggest that the GEANT4 photon evaporation database for 237Np (daughter of 241Am decay) does not accurately describe the conversion electron spectrum and therefore was found to have large discrepancies with experimental measurements. We describe how to improve the agreement between GEANT4 and alpha spectroscopy for actinides of interest by including experimental measurements of conversion electron spectroscopy into the photon evaporation database.
Frontal alpha asymmetry and sexually motivated states.
Prause, Nicole; Staley, Cameron; Roberts, Verena
2014-03-01
Anterior alpha asymmetry of electroencephalographic (EEG) signals has been suggested to index state approach (or avoidance) motivation. This model has not yet been extended to high approach-motivation sexual stimuli, which may represent an important model of reward system function. Sixty-five participants viewed a neutral and a sexually motivating film while their EEG was recorded, and reported their sexual feelings after each film. Greater alpha power in the left hemisphere during sexually motivated states was evident. A positive relationship between self-reported mental sexual arousal and alpha asymmetry was identified, where coherence between these indicators was higher in women. Notably, coherence was stronger when mental versus physical sexual arousal was rated. Alpha asymmetry appears to offer a new method for further examining this novel coherence pattern across men and women.
Nature of the pygmy dipole resonance in 140Ce studied in (alpha, alpha' gamma) experiments.
Savran, D; Babilon, M; van den Berg, A M; Harakeh, M N; Hasper, J; Matic, A; Wörtche, H J; Zilges, A
2006-10-27
A concentration of electric-dipole excitations below the particle threshold, which is frequently denoted as the pygmy dipole resonance, has been studied in the semimagic nucleus 140Ce in (alpha, alpha' gamma) experiments at E alpha = 136 MeV. The technique of alpha-gamma coincidence experiments allows the separation of E1 excitations from states of other multipolarities in the same energy region and provides an excellent energy resolution to allow a detailed analysis for each state. The experimental results show that the PDR splits into two parts with different nuclear structure: one part which is excited in (alpha, alpha' gamma) as well as (gamma, gamma') experiments and one part which is excited only in (gamma, gamma').
Alpha-emitters for medical therapy workshop
Feinendegen, L.E.; McClure, J.J.
1996-12-31
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.
Measurement of the angle alpha at BABAR
Perez, A.; /Orsay, LAL
2009-06-25
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.
[Studies on determination of alpha-amylase with p-nitrophenyl-alpha-D-maltotetraoside].
Kruse-Jarres, J D; Schott, F J; Klein, B; Rastetter, N; Wallenfels, K
1982-11-01
Nitrophenylmaltodextrins are alpha-amylase substrates which allow a continuous determination with a zero order kinetics over a period of at least 10 min, without deviations from linearity. Only one auxiliary enzyme is necessary. Practicability and clinical evidence of alpha-amylase determinations by means of p-nitrophenyl-alpha-D-maltotetraoside are demonstrated. The interserial precision of 0.84% cannot conceal an only moderate correlation with previous methods. This fact, however, does not negate the advantages.
NASA Astrophysics Data System (ADS)
Gao, Yi-Tian; Tian, Bo
The variable-coefficient nonlinear evolution equations, although realistically modeling various mechanical and physical situations, often cause some well-known powerful methods not to work efficiently. In this paper, we extend the power of the generalized hyperbolic-function method, which is based on the computerized symbolic computation, to a variable-coefficient modified Kadomtsov-Petviashvili (KP) equation and a generalized variable-coefficient KP equation. New exact analytic solutions thus come out.
Alpha-particles for targeted therapy.
Sgouros, George
2008-09-01
Alpha-particles are helium nuclei that deposit DNA damaging energy along their track that is 100 to 1000 times greater than that of conventionally used beta-particle emitting radionuclides for targeted therapy; the damage caused by alpha-particles is predominately double-stranded DNA breaks severe enough so as to be almost completely irreparable. This means that a small number of tracks through a cell nucleus can sterilize a cell and that, because the damage is largely irreparable, alpha-particle radiation is not susceptible to resistance as seen with external radiotherapy (e.g., in hypoxic tissue). The ability of a single track to influence biological outcome and the stochastic nature of alpha-particle decay require statistical or microdosimetric techniques to properly reflect likely biological outcome when the biologically relevant target is small or when a low number of radionuclide decays have occurred. In therapeutic implementations, microdosimetry is typically not required and the average absorbed dose over a target volume is typically calculated. Animal and cell culture studies have shown that, per unit absorbed dose, the acute biological effects of alpha-particles are 3 to 7 times greater than the damage caused by external beam or beta-particle radiation. Over the past ten to 15 years, alpha-particle emitting radionuclides have been investigated as a possible new class of radionuclides for targeted therapy. Results from the small number of clinical trials reported to date have shown efficacy without significant toxicity.
Is ALPHA the Odometer of the Universe?
NASA Astrophysics Data System (ADS)
Goradia, Shantilal
2007-10-01
The answer seems to be affirmative. ALPHA may be an odometer with sixty decimal points, the last digit moving up one integer every Planck time, displaying the information of the age of the universe. We can only measure it to the ninth decimal point. ALPHA is greater than or equal to the reciprocal of the natural logarithm of the age of the universe in Planck times, sixty orders of magnitude. Eddington spent good portion of his life trying to come up with a value of ALPHA based on multiplicity. Gamow had the insight about the four nucleotides of genetic tape. His deeper 1967 insight was a link between ALPHA and cosmology. Evolution mandates variation of ALPHA. In terms of the entropy equation on Boltzmann's tomb, ALPHA seems to be the Maxwell's demon, decreasing the entropy of invisible compartments within which electromagnetic interactions take place. Nature potentially knows only the Planck units. I will discuss the implications for the second law of thermodynamics drafted in physics/0210040 v3.
Binary-YORP Coefficients for Known Asteroid Shapes
NASA Astrophysics Data System (ADS)
McMahon, Jay W.; Scheeres, D. J.
2012-10-01
The binary YORP (bYORP) effect has been hypothesized to be a significant factor in the evolution of near-Earth binary asteroid systems (Cuk and Burns, Icarus, v.176, pp.418-431, 2005; McMahon and Scheeres, CMDA, v.106, pp.261-300, 2010). However, understanding of the coefficient values for realistic asteroid shapes is lacking due to the small number of shape models available for the generally smaller secondary asteroids. Until now, we have only calculated the coefficients based on the shape of 1999 KW4 Beta, although various studies by other authors have computed coefficients for artificially generated asteroids based on Gaussian Spheres and some shape models without self-shadowing (Steinberg and Sari, The Astronomical Journal, v.141, pp.55-64, 2011). We also scaled the 1999 KW4 Beta coefficients to other binary systems with no knowledge of the other systems' secondary shapes in order to make evolutionary predictions (McMahon and Scheeres, Icarus Vol. 209, pp 494-509, 2010). In this study, we compute the bYORP coefficient for a range of asteroid shapes, using these as a stand-in for actual secondaries. This allows us to circumvent the lack of information on binary asteroid secondaries and to develop a richer database of realistic coefficients. While this approach may miss some key features of binary secondaries, at the least it provides some statistics on the expected variability of the bYORP coefficient. We analyze all available asteroid shape models on the PDS-SBN, including radar-based shape models and models estimated from past spacecraft missions. The coefficients are computed with an updated algorithm that includes the effects of self-shadowing. We also present the coefficients for perturbed versions of the available shape models, which give effective error bars to the computed coefficients due to inexact shape models. Finally, we discuss the dynamical implications of the derived bYORP coefficients on binary asteroid evolution.
Liu, Ruijiang; Wang, Peng; Tao, Yuting; Liu, Yifan; Shen, Xiangqian
2016-02-01
The alpha-Fe2O3 nanotubes with diameters of 400-700 nm have been prepared via the sol-gel assisted electrospinning and subsequent one-step heat treatment with ferric nitrate, ethanol and poly(vinyl pyrrolidone) as starting regents. The resultant alpha-Fe2O3 nanotubes were characterized by XRD, SEM, TEM, and VSM techniques. The hollow structure is mainly influenced by the water content in the gel precursor and the heating rate, and the hollow formation mechanism of alpha-Fe2O9 nanotubes is discussed. Adsorption of BSA onto the as-prepared alpha-Fe2O3 nanotubes exhibits a good capacity of 56.5 mg/g with the initial BSA concentration of 1.0 mg/mL, which demonstrates their feasibility in delivery of biomacromolecules. Subsequently, the adsorption characteristics of DNA onto the alpha-Fe2O3 nanotubes were investigated, and the adsorbance of DNA can achieve a maximum value of 4.19 microg/g when the initial DNA concentration is 50 microg/mL. The adsorption process of DNA onto alpha-Fe2O3 nanotubes can be described well by the pseudo-first-order kinetic model at room temperature according to the correlation coefficient R2 = 0.9978.
Methods for the synthesis and polymerization of .alpha.,.alpha.'-dihalo-p-xylenes
Ferraris, John P.; Neef, Charles J.
2002-07-30
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.
Contribution from 3 alpha-Condensed States to the Triple-Alpha Reaction
Kato, Kiyoshi; Kurokawa, Chie; Arai, Koji
2010-06-01
The alpha-condensed state in nuclear systems has been proposed by Tohsaki et al. and has given rise to interesting discussions. The Hoyle state of {sup 12}C has been studied as the most typical example of such an alpha-condensed state. A new resonant 0{sub 3}{sup +} state (E{sub r} = 1.66 MeV, GAMMA = 1.48 MeV) is predicted as an excited alpha-condensed state in addition to the second 0{sup +} state of the Hoyle state by calculations of the 3 alpha orthogonality condition model (3 alpha OCM) using the complex scaling method. Based on this result, the breakup strengths of the inversion reaction for sequential ({sup 8}Be+alpha->{sup 12}C+gamma) and direct (alpha+alpha+alpha->{sup 12}C+gamma) processes are calculated. It is discussed that a large reaction strength calculated recently by Ogata et al. in non-resonant energies is considered as a contribution from the excited 0{sub 3}{sup +} state.
Baer, R; Boehm, T; Yssel, H; Spits, H; Rabbitts, T H
1988-01-01
We have examined DNA rearrangements within a 120 kb cloned region of the human T cell receptor J delta-C delta/J alpha-C alpha locus. Three types of pattern emerge from an analysis of T cell lines and clones. Firstly, cells with two rearrangements within J delta-C delta; secondly, cells with one rearrangement within J delta-C delta and one or more J alpha rearrangements, and finally, cells with rearrangements within J alpha and consequential deletion of the delta locus. Further analysis by cloning of rearrangements within the J alpha locus show that, in addition to V alpha-J alpha joins, J alpha-J alpha aberrant recombinations occur and rearrangement data indicate that such events are frequent. A model is presented to account for such recombinations. Images PMID:2971534
Höcker, Jan; Weber, Bernd; Tonner, Peter H; Scholz, Jens; Brand, Philipp-Alexander; Ohnesorge, Henning; Bein, Berthold
2008-03-17
alpha(2)-adrenoceptor agonists like clonidine or dexmedetomidine increase the sedative and analgesic actions of opioids. Furthermore opioids like meperidine show potent anti-shivering effects like alpha(2)-adrenoceptor agonists. The underlying molecular mechanisms of these effects are still poorly defined. The authors therefore studied the ability of four different opioids (meperidine, remifentanil, sufentanil and tramadol) to interact with different alpha(2)-adrenoceptor subtypes in mice lacking individual alpha(2A)-, alpha(2B)- or alpha(2C)-adrenoceptors (alpha(2)-adrenoceptor knock out (alpha(2)-AR KO) mice)). The interaction of opioids with alpha(2)-adrenoceptors was investigated by quantitative receptor autoradiography in brain slices of alpha(2A)-, alpha(2B)- or alpha(2C)-adrenoceptor deficient mice. Displacement of the radiolabelled alpha(2)-adrenoceptor agonist [(125)I]-paraiodoclonidine ([(125)I]-PIC) from alpha(2)-adrenoceptors in different brain regions by increasing opioid concentrations was measured, and binding affinity of the analysed opioids to alpha(2)-adrenoceptor subtypes in different brain regions was quantified. Meperidine, remifentanil and tramadol but not sufentanil provoked dose dependent displacement of specifically bound [(125)I]-PIC from all alpha(2)-adrenoceptor subtypes in cortex, cerebellum, medulla oblongata, thalamus, hippocampus and pons. Required concentrations of meperidine and remifentanil for [(125)I]-PIC displacement from alpha(2B)- and alpha(2C)-adrenoceptors were lower than from alpha(2A)-adrenoceptors, indicating higher binding affinity for alpha(2B)- and alpha(2C)-adrenoceptors. In contrast, [(125)I]-PIC displacement by tramadol indicated higher binding affinity to alpha(2A)-adrenoceptors than to alpha(2B)- and alpha(2C)-adrenoceptors. Our results indicate that meperidine, remifentanil and tramadol interact with alpha(2)-adrenoceptors in mouse brain showing different affinity for alpha(2A)-, alpha(2B)- and alpha(2C
Crop Coefficients of Some Selected Crops of Andhra Pradesh
NASA Astrophysics Data System (ADS)
Reddy, K. Chandrasekhar; Arunajyothy, S.; Mallikarjuna, P.
2015-06-01
Precise information on crop coefficients for estimating crop evapotranspiration (ETc) for regional scale irrigation planning is a major impediment in many regions. Crop coefficients suggested based on lysimeter data by earlier investigators have to be locally calibrated to account for the differences in the crop canopy under given climatic conditions. In the present study crop coefficients were derived based on reference crop evapotranspiration (ET0) estimated from Penman-Monteith equation and lysimeter measured ETc for groundnut, paddy, tobacco, sugarcane and castor crops at Tirupati, Nellore, Rajahmundry, Anakapalli and Rajendranagar centers of Andhra Pradesh respectively. Crop coefficients derived were compared with those recommended by FAO-56. The mean crop coefficients at different stages of growth were significantly different from those of FAO-56 curve though a similar trend was observed. A third order polynomial crop coefficient model has therefore been developed as a function of time (days after sowing the crop) for deriving suitable crop coefficients. The crop coefficient models suggested may be adopted to estimate crop evapotranspiration in the study area with reasonable degree of accuracy.
Coefficient of distribution of some organophosphorous pesticides in rat tissue.
Garcia-Repetto, R; Martinez, D; Repetto, M
1995-06-01
Coefficient of distribution in tissue is proposed as an indicator of the affinity of xenobiotics for different tissues and their tendency to accumulate. The present study shows the distribution of some organophosphorous pesticides in rat tissues. Using the coefficient of distribution we established the preference of these insecticides for the various tissues. Each pesticide had a specific pattern of affinity for different tissues.
Factor Scores, Structure and Communality Coefficients: A Primer
ERIC Educational Resources Information Center
Odum, Mary
2011-01-01
(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;…
Micro- and macroscale coefficients of friction of cementitious materials
Lomboy, Gilson; Sundararajan, Sriram; Wang, Kejin
2013-12-15
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.
Testing the Difference of Correlated Agreement Coefficients for Statistical Significance
ERIC Educational Resources Information Center
Gwet, Kilem L.
2016-01-01
This article addresses the problem of testing the difference between two correlated agreement coefficients for statistical significance. A number of authors have proposed methods for testing the difference between two correlated kappa coefficients, which require either the use of resampling methods or the use of advanced statistical modeling…
Analysis of a heat transfer device for measuring film coefficients
NASA Technical Reports Server (NTRS)
Medrow, R. A.; Johnson, R. L.; Loomis, W. R.; Wedeven, L. D.
1975-01-01
A heat transfer device consisting of a heated rotating cylinder in a bath was analyzed for its effectiveness to determine heat transfer coefficient of fluids. A time dependent analysis shows that the performance is insensitive to the value of heat transfer coefficient with the given rig configuration.
Visualising the Roots of Quadratic Equations with Complex Coefficients
ERIC Educational Resources Information Center
Bardell, Nicholas S.
2014-01-01
This paper is a natural extension of the root visualisation techniques first presented by Bardell (2012) for quadratic equations with real coefficients. Consideration is now given to the familiar quadratic equation "y = ax[superscript 2] + bx + c" in which the coefficients "a," "b," "c" are generally…
Temperature dependence of the diffusion coefficient of nanoparticles
NASA Astrophysics Data System (ADS)
Rudyak, V. Ya.; Dubtsov, S. N.; Baklanov, A. M.
2008-06-01
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.
Biases and Standard Errors of Standardized Regression Coefficients
ERIC Educational Resources Information Center
Yuan, Ke-Hai; Chan, Wai
2011-01-01
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…
Graphical Solution of the Monic Quadratic Equation with Complex Coefficients
ERIC Educational Resources Information Center
Laine, A. D.
2015-01-01
There are many geometrical approaches to the solution of the quadratic equation with real coefficients. In this article it is shown that the monic quadratic equation with complex coefficients can also be solved graphically, by the intersection of two hyperbolas; one hyperbola being derived from the real part of the quadratic equation and one from…
A program to compute aquifer-response coefficients
Maddock, Thomas
1974-01-01
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.
Thermosphere Density Variability, Drag Coefficients, and Precision Satellite Orbits
2013-07-29
complex satellites. 1 Introduction Atmospheric density and drag coefficient modeling have long been among the greatest uncertainties in the...limitation of existing theories for satellite drag coefficients. In addition, the research will examine whether modern computational fluids...2005) gives an introduction to the neutral atmosphere and the time varying effects on the thermospheric and exospheric density. These time varying
ESTIMATING DISSOLVED ORGANIC CARBON PARTITION COEFFICIENTS FOR NONIONIC ORGANIC CHEMICALS
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...
REE and Strontium Partition Coefficients for Nakhla Pyroxenes
NASA Technical Reports Server (NTRS)
Oe, K.; McKay, G.; Le, L.
2001-01-01
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..
Determination of storage coefficients during pumping and recovery.
Ashjari, Javad
2013-01-01
An aquifer test is used mostly to determine the storage coefficient and transmissivity. Although residual drawdown data are widely used in estimating the transmissivity of aquifers, the estimation of storage coefficients with recovery data is controversial. Some researchers have proposed methods to estimate storage coefficients with recovery data by assuming equality of storage coefficients for the recovery and pumping periods (S = S'). The aim of this study is to determine storage coefficients without such an assumption, that is, S≠S'. The method is a modified version of Banton-Bangoy's method without considering drawdown data due to pumping. Drawdown is plotted vs. the logarithmic ratio (t'/t) or time since pumping stopped to the duration of pumping and the ratio of storage coefficient during recovery to the storage coefficient from the pumping period (S'/S). The method is verified with one case study and two synthetic examples. Thus, it is possible to determine storage coefficient of pumping period accurately without any data from pumping period by recovery data.