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1

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

ERIC Educational Resources Information Center

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

Ritter, Nicola L.

2010-01-01

2

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

ERIC Educational Resources Information Center

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

Kistner, Emily O.; Muller, Keith E.

2004-01-01

3

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

ERIC Educational Resources Information Center

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

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

2006-01-01

4

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

ERIC Educational Resources Information Center

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

Yang, Yanyun; Green, Samuel B.

2011-01-01

5

Coefficient Alpha Bootstrap Confidence Interval under Nonnormality  

ERIC Educational Resources Information Center

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

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

2012-01-01

6

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

ERIC Educational Resources Information Center

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

Rae, Gordon

2006-01-01

7

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

SciTech Connect

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

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

2009-12-31

8

A Comparison of Tests for Equality of Two or More Independent Alpha Coefficients  

ERIC Educational Resources Information Center

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…

Kim, Seonghoon; Feldt, Leonard S.

2008-01-01

9

A Reliability Generalization Study of Coefficient Alpha for the Life Orientation Test  

Microsoft Academic Search

Dispositional optimism is a widely studied construct in social science and medicine associated with a variety of important psychological and physiological outcomes. Our purpose in this study was to examine coefficient alpha for a popular optimism measure: The Life Orientation Test (LOT; Scheier & Carver, 1985). We utilized a meta-analytic procedure known as reliability generalization to provide an aggregate estimate

Matt Vassar; Greg Bradley

2010-01-01

10

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

NASA Astrophysics Data System (ADS)

Part of the energy of the Lower Hybrid (LH) waves may be absorbed by the ? particles via the so-called perpendicular landau damping mechanism, which depends on various parameters of fusion reactors and the LH waves. In this article, we calculate the absorption coefficient ?? of LH waves due to ? particles. Results show that, the ?? increases with the parallel refraction index n? while deceases with increasing the frequency of LH waves ?LH over a wide range. Higher background plasma temperature and toroidal magnetic field will increase the absorption, and there is a peak value of ?? when ne?8×1019m-3 for ITER-like scenario. The thermal corrections to the cold plasma dispersion relation will change the damping rate to a certain extent under some specific conditions. We have also evaluated the fraction of LH power absorbed by the alpha particles, ? ? 0.47% and 4.1% for an LH frequency of 5 GHz and 3.7 GHz respectively for ITER-like scenario. This work gives the effective reference for the choice of parameters of future fusion reactors.

Wang, Jianbing; Zhang, Xianmei; Yu, Limin; Zhao, Xiang

2014-02-01

11

MEASUREMENT OF THE COEFFICIENT OF FRICTION BETWEEN URANIUM AND STEEL AT HIGH ALPHA-URANIUM TEMPERATURES  

Microsoft Academic Search

Results of the tests to determine coefficient of friction data between ; uranium at 1050 to 1200 nif- F and steel dies are presented. For the ; temperature range considered, the values for the coefficient of friction as ; calculated by the Amonton equation are relatively independent of temperature. ; The friction coefficient values were highest for the 450 BHN

E. S. Hodge; R. J. Carlson; E. G. Bodine; E. G. Jr. Smith

1963-01-01

12

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

NASA Technical Reports Server (NTRS)

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

Guiot, R.; Wunnenberg, H.

1980-01-01

13

ELECTRONIC SUPPLEMENTARY MATERIAL Table S1. Internal reliability (Cronbach's ) for the Big Five and Tsimane-specific Big Two personality factors (Adapted from Table 1, Gurven et  

E-print Network

) Cronbach's Extraversion (7) 0.77 Neuroticism (7) 0.37 Agreeableness (8) 0.65 Conscientiousness (8) 0) Extraversion Neuroticism Agreeableness Conscientious- ness Openness Pro-sociality Extraversion not shown) Agreeableness Conscientiousness Extraversion Neuroticism Openness Parameter B P B P B P B P B P

Gurven, Michael

14

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

E-print Network

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

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

2008-05-23

15

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

E-print Network

A new analysis of the precise experimental astrophysical $S$ factors for the direct capture $^3He(\\alpha,\\gamma)^7{\\rm {Be}}$ reaction [B.S. Nara Singh et al., Phys.Rev.Lett. {\\bf 93} (2004) 262503; D. Bemmerer et al., Phys.Rev.Lett. {\\bf 97} (2006) 122502; F.Confortola et al., Phys.Rev.C {\\bf 75} (2007) 065803 and T.A.D.Brown et al., Phys.Rev. C {\\bf 76} (2007) 055801] populating to the ground and first excited states of $^7{\\rm Be}$ is carried out based on the modified two - body potential approach in which the direct astrophysical $S$ factor, $S_{34}(E)$, is expressed in terms of the asymptotic normalization constants for $^3{\\rm {He}}+\\alpha\\to ^7{\\rm {Be}}$ and two additional conditions are involved to verify the peripheral character of the reaction under consideration. The Woods--Saxon potential form is used for the bound ($\\alpha+^3{\\rm {He}}$)- state and the $^3{\\rm {He}}\\alpha$- scattering wave functions. New estimates are obtained for the $^{\\glqq}$indirectly measured\\grqq values of the asymptotic n...

Igamov, S B; Yarmukhamedov, R

2009-01-01

16

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

E-print Network

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

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

2009-05-13

17

Coefficient scaling.  

PubMed

We prove a remarkably simple but powerful recursion relation for the coefficients of iterated polynomials. We also prove that the recursion relation holds for the coefficients of certain functions of the iterated polynomial. Using the recursion relations, we obtain a closed-form expression for the average number of closed-loop self-avoiding walks per site on a family of fractal lattices. We describe numerical results, which exhibit log-periodic oscillations, and find good agreement between these results and the theory developed here, which predicts the existence of the log-periodic oscillations and their amplitudes. Finally, we discuss insights gained into the mathematical origins of critical phenomena. PMID:11969435

Paul, G

1999-05-01

18

Alpha Particle  

NASA Astrophysics Data System (ADS)

Term that is sometimes used to describe a helium nucleus, a positively charged particle that consists of two protons and two neutrons, bound together. Alpha particles, which were discovered by Ernest Rutherford (1871-1937) in 1898, are emitted by atomic nuclei that are undergoing alpha radioactivity. During this process, an unstable heavy nucleus spontaneously emits an alpha particle and transmut...

Murdin, P.

2000-11-01

19

Factor Scores, Structure Coefficients, and Communality Coefficients  

ERIC Educational Resources Information Center

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

Goodwyn, Fara

2012-01-01

20

Prediction of coefficients of thermal expansion for unidirectional composites  

NASA Technical Reports Server (NTRS)

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

Bowles, David E.; Tompkins, Stephen S.

1989-01-01

21

Alpha Thalassemia  

MedlinePLUS

... an apparently normal individual has a child with hemoglobin H disease or alpha thalassemia minor. It can ... pregnancy that their child will be born with hemoglobin H disease in which three of the four ...

22

Scale setting for alphas beyond leading order  

Microsoft Academic Search

We present a general procedure for incorporating higher-order information into the scale-setting prescription of Brodsky, Lepage and Mackenzie. In particular, we show how to apply this prescription when the leading coefficient or coefficients in a series in the strong coupling alphas are anomalously small and the original prescription can give an unphysical scale. We give a general method for computing

K. Hornbostel; G. P. Lepage; C. Morningstar

2003-01-01

23

Alpha-1 Antitrypsin Deficiency  

MedlinePLUS

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

24

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

ERIC Educational Resources Information Center

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

Revelle, William; Zinbarg, Richard E.

2009-01-01

25

Sample Size Requirements for Comparing Two Alpha Coefficients.  

ERIC Educational Resources Information Center

Derived general formulas to determine the sample size requirements for hypothesis testing with desired power and interval estimation with desired precision. Illustrated the approach with the example of a screening test for adolescent attention deficit disorder. (SLD)

Bonnett, Douglas G.

2003-01-01

26

Alpha-1 Panniculitis  

MedlinePLUS

... medical conditions, panniculitis can have many underlying causes. Alpha-1 Antitrypsin Deficiency (Alpha-1) is one of those causes. There ... the rarest of the well-known complications of Alpha-1 Antitrypsin Deficiency. In those with Alpha-1 (called Alphas), the ...

27

Liver and Alpha-1  

MedlinePLUS

... CSL Behring Grifols The mission of the Alpha-1 Foundation is to provide the leadership and resources ... information, visit: www.alpha-1foundation.org. The Alpha-1 Association is the leading national patient membership organization ...

28

Alpha-1 Antitrypsin Deficiency  

MedlinePLUS

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

29

Special Space Curves Characterized by det({\\alpha}^{(3)}, {\\alpha}^{(4)},{\\alpha}^{(5)})=0  

E-print Network

In this study, by using the facts that det({\\alpha}^{(1)}, {\\alpha}^{(2)}, {\\alpha}^{(3)}) = 0 characterizes plane curve, and det({\\alpha}^{(2)}, {\\alpha}^{(3)}, {\\alpha}^{(4)}) = 0 does a curve of constant slope, we give the special space curves that are characterized by det({\\alpha}^{(3)}, {\\alpha}^{(4)}, {\\alpha}^{(5)}) = 0, in different approaches. We find that the space curve is Salkowski if and only if det({\\alpha}^{(3)}, {\\alpha}^{(4)}, {\\alpha}^{(5)}) = 0. The approach we used in this paper is useful in understanding the role of the curves that are characterized by det({\\alpha}^{(3)}, {\\alpha}^{(4)}, {\\alpha}^{(5)})=0 in differential geometry.

Yayali, Yusuf

2012-01-01

30

Dynamic Ly alpha jets  

E-print Network

The solar chromosphere and transition region are highly structured and complex regimes. A recent breakthrough has been the identification of dynamic fibrils observed in H alpha as caused by field-aligned magnetoacoustic shocks. We seek to find whether such dynamic fibrils are also observed in Ly alpha. We used a brief sequence of four high-resolution Ly alpha images of the solar limb taken by the Very high Angular resolution ULtraviolet Telescope (VAULT), which displays many extending and retracting Ly alpha jets. We measured their top trajectories and fitted parabolas to the 30 best-defined ones. Most jet tops move supersonically. Half of them decelerate, sometimes superballistically, the others accelerate. This bifurcation may arise from incomplete sampling of recurrent jets. The similarities between dynamic Ly alpha jets and H alpha fibrils suggest that the magnetoacoustic shocks causing dynamic H alpha fibrils also affect dynamic Ly alpha jets.

J. Koza; R. J. Rutten; A. Vourlidas

2008-07-30

31

GROSS ALPHA RADIUM REGULATION  

EPA Science Inventory

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

32

The Alpha Centauri System.  

ERIC Educational Resources Information Center

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)

Soderblom, David R.

1987-01-01

33

Alpha, Dimension-Free, and Model-Based Internal Consistency Reliability  

ERIC Educational Resources Information Center

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 proposed to…

Bentler, Peter M.

2009-01-01

34

Semiparametric Estimation of Index Coefficients  

Microsoft Academic Search

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

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

1989-01-01

35

Interpreting EEG alpha activity.  

PubMed

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. PMID:23701947

Bazanova, O M; Vernon, D

2014-07-01

36

Absorption Coefficient Measurrement of Monochromatized Synchrotron Radiation at 0.65 - 1.3 A Interval for Some Biological Objects.  

National Technical Information Service (NTIS)

The results of the measurement of absorption coefficients for some biological objects such as pea (Pisum sativum), wheat (Triticum aestivum), tobacco (Nicotiana tabacum- alpha ) seeds, as well as the distilled water are presented. The measurement has been...

T. M. Avakian, I. P. Karabekov, M. A. Martirossian

1977-01-01

37

Approximate formulation of redistribution in the Ly-alpha, Ly-beta, H-alpha system  

NASA Technical Reports Server (NTRS)

Simple approximate formulas are given for the coupled redistribution of Ly-alpha, Ly-beta, and H-alpha, by using well-defined approximations to an essentially exact formulation. These formulas incorporate all the essential physics including Raman scattering, lower state radiative decay, and correlated terms representing emission during a collision which must be retained in order that the emission coefficients are properly behaved in the line wings. Approximate expressions for the appropriate line broadening parameters are collected. Finally, practical expressions for the source functions are given. These are formulated through newly introduced nonimpact redistribution functions, which are shown to be reasonably approximated by existing (ordinary and generalized) redistribution functions.

Cooper, J.; Ballagh, R. J.; Hubeny, I.

1989-01-01

38

Imaging alpha particle detector  

DOEpatents

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.

Anderson, D.F.

1980-10-29

39

Event counting alpha detector  

DOEpatents

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

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

1996-01-01

40

Imaging alpha particle detector  

DOEpatents

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

Anderson, David F. (Los Alamos, NM)

1985-01-01

41

Event counting alpha detector  

DOEpatents

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

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

1996-08-27

42

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

SciTech Connect

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

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

2011-09-15

43

Development of a Psychopathology Rating Scale for Children With Mental Retardation  

Microsoft Academic Search

A total of 583 children and adolescents with mental retardation were rated on a new psychometric instrument designed to screen for dual diagnosis (psychopathology in individuals with mental retardation). Two psychiatrists and two clinical psychologists judged the items to have face validity as expressions of psychopathology in children and adolescents with mental retardation. Cronbach’s alpha coefficient was .91 for the

Steven Reiss; Denise Valenti-Hein

1994-01-01

44

Conversion coefficients for superheavy elements  

E-print Network

In this paper we report on internal conversion coefficients for Z = 111 to Z = 126 superheavy elements obtained from relativistic Dirac-Fock (DF) calculations. The effect of the atomic vacancy created during the conversion process has been taken into account using the so called "Frozen Orbital" approximation. The selection of this atomic model is supported by our recent comparison of experimental and theoretical conversion coefficients across a wide range of nuclei. The atomic masses, valence shell electron configurations, and theoretical atomic binding energies required for the calculations were adopted from a critical evaluation of the published data. The new conversion coefficient data tables presented here cover all atomic shells, transition energies from 1 keV up to 6000 keV, and multipole orders of 1 to 5. A similar approach was used in our previous calculations [1] for Z = 5 - 110.

T. Kibédi; M. B. Trzhaskovskaya; M. Gupta; A. E. Stuchbery

2011-03-03

45

Conversion coefficients for superheavy elements  

E-print Network

In this paper we report on internal conversion coefficients for Z = 111 to Z = 126 superheavy elements obtained from relativistic Dirac-Fock (DF) calculations. The effect of the atomic vacancy created during the conversion process has been taken into account using the so called "Frozen Orbital" approximation. The selection of this atomic model is supported by our recent comparison of experimental and theoretical conversion coefficients across a wide range of nuclei. The atomic masses, valence shell electron configurations, and theoretical atomic binding energies required for the calculations were adopted from a critical evaluation of the published data. The new conversion coefficient data tables presented here cover all atomic shells, transition energies from 1 keV up to 6000 keV, and multipole orders of 1 to 5. A similar approach was used in our previous calculations [1] for Z = 5 - 110.

Kibédi, T; Gupta, M; Stuchbery, A E

2011-01-01

46

Method for determining damping coefficients  

NASA Astrophysics Data System (ADS)

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

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

1995-05-01

47

Seebeck coefficient of one electron  

NASA Astrophysics Data System (ADS)

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

Durrani, Zahid A. K.

2014-03-01

48

Coaching the alpha male.  

PubMed

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. PMID:15146736

Ludeman, Kate; Erlandson, Eddie

2004-05-01

49

Alpha Particle Diagnostic  

SciTech Connect

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

Fisher, Ray, K.

2009-05-13

50

Dependence of the elastic strain coefficient of copper on the pre-treatment  

NASA Technical Reports Server (NTRS)

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.

Kuntze, Wilhelm

1950-01-01

51

Measurement of Impact Ionization Coefficients in Gallium Nitride  

NASA Astrophysics Data System (ADS)

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

Ozbek, Ayse Merve

52

NOMENCLATURE CD fuselage drag coefficient  

E-print Network

coefficient F vector of overall forces and moments l fuselage half-length Nb number of blades R rotor radius vi induced velocity advance ratio blade azimuth rotor rotational speed Subscripts/superscripts c coaxial helicopter with a stiff main rotor system and a tail-mounted propulsor are investigated using

Alonso, Juan J.

53

Geometrical content of Leslie coefficients  

NASA Astrophysics Data System (ADS)

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

Simões, M.; da Silva, J. L. Correia

2011-05-01

54

Coefficient of Meteor Plasma Radiation  

Microsoft Academic Search

We present a historical review of the problem of obtaining the meteor plasma radiation coefficient. Meteor spectrophotometry endures to fail in determining spectral line profiles, because an existing spectrograph has to give a monochrome image of the meteors instead of a spectral line. Therefore, it is rather difficult to take the self-absorption magnitude as affecting the decrease of radiation intensity

V. A. Smirnov

2000-01-01

55

Effective Viscosity Coefficient of Nanosuspensions  

NASA Astrophysics Data System (ADS)

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.

Rudyak, V. Ya.; Belkin, A. A.; Egorov, V. V.

2008-12-01

56

Conversion coefficients for superheavy elements  

Microsoft Academic Search

In this paper we report on internal conversion coefficients for Z = 111 to Z = 126 superheavy elements obtained from relativistic Dirac-Fock (DF) calculations. The effect of the atomic vacancy created during the conversion process has been taken into account using the so called \\

T. Kibédi; M. B. Trzhaskovskaya; M. Gupta; A. E. Stuchbery

2011-01-01

57

Logistic Regression with Random Coefficients.  

ERIC Educational Resources Information Center

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

Longford, Nicholas T.

58

Identities for generalized hypergeometric coefficients  

SciTech Connect

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

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

1991-01-01

59

EEG alpha power and intelligence  

Microsoft Academic Search

The hypothesis was tested whether alpha power in different subbands (lower-1, lower-2, and upper alpha) is selectively related to intelligence. For 74 subjects, the EEG was recorded during a resting session. Two different intelligence tests (LGT-3 and IST-70) were performed. We found a strong positive correlation between intelligence and alpha power. Large differences between the two intelligence tests and alpha

M. Doppelmayr; W. Klimesch; W. Stadler; D. Pöllhuber; C. Heine

2002-01-01

60

Learning about Alpha-1 Antitrypsin Deficiency (AATD)  

MedlinePLUS

... terms used on this page Learning About Alpha-1 Antitrypsin Deficiency (AATD) What is alpha-1 antitrypsin ... for Alpha-1 Anttrypsin Deficiency What is alpha-1 antitrypsin defciency? Alpha-1 antitrypsin deficiency (AATD) is ...

61

Neural Network Prediction of New Aircraft Design Coefficients  

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

62

Solar flare alpha particles  

NASA Technical Reports Server (NTRS)

Interplanetary disturbances frequently change the instantaneous values of the low energy solar flare alpha-to-proton flux ratios. The fluxes of alpha particles were integrated over the duration of seven large solar events occurring between May 28, 1967, and November 6, 1969, in order to investigate the total alpha particles fluxes observed at 1 AU resulting from the flares. The spectra of the event integrated alphas are always softer than the spectra of the event integrated protons. As a consequence, the event-integrated alpha-to-proton ratios decrease slightly with increasing energy per nucleon. The He-4/H-1 ratios averaged over the seven events are found to vary as 0.026 (E/nucl) sup -0.2 in the range 1 to 10 MeV/nucleon. The value of the ratio at 1 MeV/nucleon is less than the helium-to-hydrogen abundance determined from spectroscopic studies of prominences and the chromosphere, and is less than the average solar wind helium-to-hydrogen abundance.

Lanzerotti, L. J.

1973-01-01

63

High temperature Seebeck coefficient metrology  

SciTech Connect

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

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

2010-12-15

64

Portable vapor diffusion coefficient meter  

DOEpatents

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

Ho, Clifford K. (Albuquerque, NM)

2007-06-12

65

Alpha-Particle Gas-Pressure Sensor  

NASA Technical Reports Server (NTRS)

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

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

1996-01-01

66

{sup 14}C({alpha},{gamma}) reaction rate  

SciTech Connect

The {sup 14}C({alpha},{gamma}) reaction rate at temperatures below 0.3 GK depends on the properties of two near threshold resonances in {sup 18}O, the 1{sup -} at 6.198 MeV and the 3{sup -} at 6.404 MeV. The {alpha}+{sup 14}C asymptotic normalization coefficients for these resonances were determined using the {alpha}-transfer reactions {sup 14}C({sup 7}Li, t) and {sup 14}C({sup 6}Li, d) at sub-Coulomb energies. The {sup 14}C({alpha},{gamma}) reaction rate at low temperatures has been evaluated. Implications of the new reaction rate on the evolution of accreting helium white dwarfs and on the nucleosynthesis of low mass stars during the asymptotic giant branch phase are discussed.

Johnson, E. D.; Rogachev, G. V.; Mitchell, J.; Miller, L.; Kemper, K. W. [Department of Physics, Florida State University, Florida 32306 (United States)

2009-10-15

67

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

NASA Astrophysics Data System (ADS)

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

Dasgupta-Schubert, N.; Reyes, M. A.

2007-11-01

68

AlphaGalileo  

NSDL National Science Digital Library

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

69

Semiconductor polycrystalline alpha detectors  

NASA Astrophysics Data System (ADS)

In order to check possible novel neutron detectors based on composite semiconductor detectors containing nuclides with large cross sections for neutron, we tested their response to alpha particles. In the present paper we describe results obtained with composite samples made of hexagonal Boron Nitride particles bound with Polystyrene or Nylon-6. The samples were tested under 5.5 MeV alpha particle radiation emitted from 241Am source and 4.8MeV alpha particle of 226Ra source. Some of the responses of these composite detectors to thermal neutrons were already reported and here we shall show some newer results obtained with thermal neutrons, from a low intensity 241Am - 9Be and also from a medium intensity 252Cf source, which were thermalized using 10 cm thick paraffin. The Alpha detection experiments show that all the tested samples, regardless of the binder, show a well-defined peak around the 270 energy channel. There was very little polarization of the alpha radiation, since the amplitude of the alpha peak is reduced after ~ 2min from start of the irradiation, from 100% to 95% and it stayed stable at this level for another 10 minutes. The alpha spectrum detected from a PbI II single crystal is also shown for comparison. The neutron spectrum obtained by the composite BN samples showed an apparent peak around the 150 energy channel. The Signal to noise ratio for neutron detection from radionuclide shown here is about 2 only, whereas recent results to be published later, obtained with our composite BN detectors from a neutron beam of about 10 7 sec -1cm -2 is ~2 5. The 1.4 and 1.7 MeV alpha peaks resulting from the nuclear reaction of thermal neutrons with 10B of the boron nitride detector are not buried in the noise range. The capacitance noise requires small contact areas, therefore for large area detectors it is necessary to produce an electronic read-out device which can add up a multitude of small (less than 10sq.mm) pixilated contacts.

Schieber, M.; Roth, M.; Zuck, A.; Marom, G.; Khakhan, O.; Alfassi, Z. B.

2006-08-01

70

The Apollo Alpha Spectrometer.  

NASA Technical Reports Server (NTRS)

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

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

1973-01-01

71

On the Validity of the Geiger-Nuttall Alpha-Decay Law and its Microscopic Basis  

E-print Network

The Geiger-Nuttall (GN) law relates the partial $\\alpha$-decay half-life with the energy of the escaping $\\alpha$ particle and contains for every isotopic chain two experimentally determined coefficients. The expression is supported by several phenomenological approaches, however its coefficients lack a fully microscopic basis. In this paper we will show that: 1) the empirical coefficients that appear in the GN law have a deep physical meaning and 2) the GN law is successful within the restricted experimental data sets available so far, but is not valid in general. We will show that, when the dependence of logarithm values of the $\\alpha$ formation probability on the neutron number is not linear or constant, the GN law is broken. For the $\\alpha$ decay of neutron-deficient nucleus $^{186}$Po, the difference between the experimental half-life and that predicted by the GN Law is as large as one order of magnitude.

Qi, C; Huyse, M; Liotta, R J; Van Duppen, P; Wyss, R

2014-01-01

72

On the Validity of the Geiger-Nuttall Alpha-Decay Law and its Microscopic Basis  

E-print Network

The Geiger-Nuttall (GN) law relates the partial $\\alpha$-decay half-life with the energy of the escaping $\\alpha$ particle and contains for every isotopic chain two experimentally determined coefficients. The expression is supported by several phenomenological approaches, however its coefficients lack a fully microscopic basis. In this paper we will show that: 1) the empirical coefficients that appear in the GN law have a deep physical meaning and 2) the GN law is successful within the restricted experimental data sets available so far, but is not valid in general. We will show that, when the dependence of logarithm values of the $\\alpha$ formation probability on the neutron number is not linear or constant, the GN law is broken. For the $\\alpha$ decay of neutron-deficient nucleus $^{186}$Po, the difference between the experimental half-life and that predicted by the GN Law is as large as one order of magnitude.

C. Qi; A. N. Andreyev; M. Huyse; R. J. Liotta; P. Van Duppen; R. Wyss

2014-05-22

73

Dissociative recombination coefficients for H3(+), HCO(+), N2H(+), and CH5(+) at low temperature - Interstellar implications  

NASA Astrophysics Data System (ADS)

The results obtained from a recent laboratory study of the dissociative recombination coefficients, alpha, at 95 and 300 K for the important interstellar ions H3(+), HCO(+), N2H(+) and CH5(+). The most important result of the study is that alpha-H3(+) is much smaller than previous studies had indicated, so small that it was only possible to obtain an upper limit value at both temperatures. However, the values of alpha-HCO(+), alpha-N2H(+) and alpha-CH5(+) have been determined at both temperatures, and they are in accordance with expectations based on previous laboratory data. The smaller alpha-H3(+) implies a larger fractional ionization of dense interstellar clouds than previous estimates had indicated. Some possible consequences of a higher ionization density to the physics and chemistry of dense clouds are mentioned.

Smith, D.; Adams, N. G.

1984-09-01

74

[alpha]-Oxocarboxylic Acids  

ERIC Educational Resources Information Center

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

Kerber, Robert C.; Fernando, Marian S.

2010-01-01

75

Alpha Hydroxy Acids  

MedlinePLUS

... skin or mucous membrane, such as the lips, bear a statement that conveys the following information: Sunburn Alert: This product contains an alpha hydroxy acid (AHA) that may increase your skin's sensitivity to the sun and particularly the possibility of sunburn. Use a ...

76

The Production Coefficients of Feeds  

E-print Network

.. deduct 0.14. The following is an example of the method of calculating the fat value of a roughage : JOHNSON GRASS HAY, 100 POUNDS. Digestible protein ............. 3.3 XO.235= 0.78 Digestible fat ................. O.YX0.474= 0... of the Johnson grass hay added *to a ration already sufficient to maintain the animal should produce 8.21 pounds fat. The fat value is the productive value for fattening, when the feed is used for fat and for no other purpose. THE PRODUCTION COEFFICIENT...

Fraps, G. S. (George Stronach)

1916-01-01

77

The ultraviolet spectra of Alpha Aquilae and Alpha Canis Minoris  

Microsoft Academic Search

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

D. C. Morton; G. Bruzual A; R. L. Kurucz; H. Spinrad

1977-01-01

78

Osmotic coefficients of electrolyte solutions.  

PubMed

In this paper, the osmotic coefficient, phi, of electrolyte solutions is considered. According to the Gibbs-Duhem equation, the calculation of phi follows from that of the mean activity coefficient, gamma, based on a pseudolattice approach recently proposed. For any given electrolyte, the whole range of concentrations providing gamma

Moggia, Elsa

2008-01-31

79

Virial coefficients of model alkanes  

NASA Astrophysics Data System (ADS)

We report the results from Mayer-sampling Monte Carlo calculations of the virial coefficients of the united-atom TraPPE-UA model of normal alkanes. For alkane chain lengths from n =2 to 20 (where n is the number of carbon atoms), results are given for the virial coefficients B2, B3, and B4; results for B5 are given for chains up to length n =12; and results for B6 are given for chains of length n =2, 3, and 4. In all cases, values are given for temperatures ranging from 200 K to 2000 K in 20-50 K increments. The values are used to calculate the equation of state for butane and the pressure-density behavior is compared to experimental data at 350 and 550 K. Critical points are calculated for all systems and compared to simulation data previously taken for the same molecular model, and to experiment. The comparison with temperature is very good (within 1.5% for all chain lengths up to n =12), while the critical density is underestimated by about 5%-15% and the critical pressure is given within about 10%. The convergence behavior of the virial equation of state as applied across the n-alkane series is well characterized by corresponding states, meaning that the accuracy at a given density relative to the critical density does not deteriorate with increasing chain length.

Schultz, Andrew J.; Kofke, David A.

2010-09-01

80

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

SciTech Connect

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

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

2009-11-15

81

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

SciTech Connect

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

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

1985-01-01

82

M-Bonomial Coefficients and Their Identities  

ERIC Educational Resources Information Center

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

Asiru, Muniru A.

2010-01-01

83

Third Order Elastic Coefficients of Rocks  

Microsoft Academic Search

We present a methodology to determine third order elastic (TOE) coefficients of rock from velocity measurements at different hydrostatic stress level. TOE coefficients help us to obtain a quantitative measure of the variation of velocity with stress. It is one of the most general ways to parameterize the stress sensitivity of rocks. We usually determine the isotropic TOE coefficients from

K. Bandyopadhyay

2006-01-01

84

Soccer Ball Lift Coefficients via Trajectory Analysis  

ERIC Educational Resources Information Center

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

Goff, John Eric; Carre, Matt J.

2010-01-01

85

Radiation Pressure in Lyman-alpha Forest Clouds  

E-print Network

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

Michael Fisher

2007-05-01

86

Alpha models and boundary-layer turbulence  

NASA Astrophysics Data System (ADS)

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.

Cheskidov, Alexey

87

Inference of the aerosol Angstrom coefficient from SAGE short-wavelength data. [Stratospheric Aerosol and Gas Experiment  

NASA Technical Reports Server (NTRS)

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.

Lenoble, J.; Pruvost, P.

1983-01-01

88

Radon emanation coefficients for phosphogypsum.  

PubMed

Phosphogypsum is a by-product of the phosphate fertilizer industry which is stockpiled in large quantities world-wide. Phosphogypsum consists mainly of dihydrate gypsum (CaSO42H2O) but also contains elevated concentrations of 226Ra and other inorganic species which originate from the processing of phosphate rock. 222Rn gas is the first decay product of 226Ra and has been identified as one of the major environmental concerns associated with phosphogypsum. This study was conducted to determine effects of particle size, weathering, and moisture content on the 222Rn emanation coefficient (epsilon) for phosphogypsum. Average epsilon for air-dry, unfractionated phosphogypsums derived from Togo, Florida, or Idaho rock was approximately 12%. Average epsilon for fine fraction phosphogypsum (< 20 microns diameter) was greater than for unfractionated phosphogypsum by a factor of 4.6, 1.4, and 4.4 for samples derived from Idaho rock, Togo rock, and Florida rock, respectively. Phosphogypsum samples subjected to an artificial weathering procedure lost 40% mass, with no change in epsilon. Increasing water content was found to first slightly decrease, then to increase epsilon compared to air-dry samples; epsilon for 100% saturated phosphogypsum was 1.9-fold greater than in air-dry phosphogypsum. Particle size sorting could account for variability of 222Rn exhalation at repositories. Very high moisture contents could slightly increase 222Rn emanation, but exhalation would likely be reduced due to slow diffusion through porosity of saturated phosphogypsum. PMID:7558842

Rutherford, P M; Dudas, M J; Arocena, J M

1995-10-01

89

Index-free heat kernel coefficients  

NASA Astrophysics Data System (ADS)

Using index-free notation, we present the diagonal values 0264-9381/15/8/014/img1 of the first five heat kernel coefficients 0264-9381/15/8/014/img2 associated with a general Laplace-type operator on a compact Riemannian space without boundary. The fifth coefficient 0264-9381/15/8/014/img3 appears here for the first time. For the special case of a flat space, but with a gauge connection, the sixth coefficient is given too. Also provided are the leading terms for any coefficient, both in ascending and descending powers of the Yang-Mills and Riemann curvatures, to the same order as required for the fourth coefficient. These results are obtained by directly solving the relevant recursion relations, working in the Fock-Schwinger gauge and Riemann normal coordinates. Our procedure is thus non-covariant, but we show that for any coefficient the `gauged', respectively `curved', version is found from the corresponding `non-gauged', respectively `flat', coefficient by making some simple covariant substitutions. These substitutions being understood, the coefficients retain their `flat' form and size. In this sense the fifth and sixth coefficient have only 26 and 75 terms, respectively, allowing us to write them down. Using index-free notation also clarifies the general structure of the heat kernel coefficients. In particular, in flat space we find that from the fifth coefficient onward, certain scalars are absent. This may be relevant for the anomalies of quantum field theories in ten or more dimensions.

van de Ven, Anton E. M.

1998-08-01

90

Alpha-mannosidosis  

PubMed Central

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

Malm, Dag; Nilssen, Øivind

2008-01-01

91

An alpha scintillation spectrometer  

E-print Network

. Uranium 1'hick Uranium sources were tested to determine if any differences would exist between the oulse height distribution oi' thick Uranium and Thorium sources. Sources were prepared by placing small pieces of Uranium nitrate, UO2 (NO3)2 6H20, on a... phosphor covered light-piper. The ten different energy alpha particles that were emitted from the Uranium were blended into a continuous distribution, there being no apparent difference between this and the thick Thorium distribution. The same was true...

Yates, Ralph Aaron

2012-06-07

92

Finite Range Effects in (alpha, 2alpha) Reactions  

SciTech Connect

Finite range calculations for the (alpha, 2alpha) reactions are performed for the first time to remove huge inconsistencies obtained earlier in conventional zero range analyses. Vagaries of the energy dependent experimental observations up to 200 MeV are understood using the well-established nuclear radii and distorting optical potentials. The results are found to be sensitive to the short distance behavior of the alpha-alpha interaction, indicating the utility of the knockout reactions as a probe of the knockout vertex at short distances. Our approach paves the way to include finite range effects in atomic and molecular physics as also in neutron multiplication calculations.

Jain, Arun K.; Joshi, Bhushan N. [Nuclear Physics Division, Bhabha Atomic Research Center, Mumbai-400 085 (India)

2009-09-25

93

Substitutional and Interstitial Diffusion in alpha2-Ti3Al(O)  

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

94

Background canceling surface alpha detector  

DOEpatents

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

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

1996-01-01

95

Background canceling surface alpha detector  

DOEpatents

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

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

1996-06-11

96

Nuclear Alpha-Particle Condensates  

E-print Network

The $\\alpha$-particle condensate in nuclei is a novel state described by a product state of $\\alpha$'s, all with their c.o.m. in the lowest 0S orbit. We demonstrate that a typical $\\alpha$-particle condensate is the Hoyle state ($E_{x}=7.65$ MeV, $0^+_2$ state in $^{12}$C), which plays a crucial role for the synthesis of $^{12}$C in the universe. The influence of antisymmentrization in the Hoyle state on the bosonic character of the $\\alpha$ particle is discussed in detail. It is shown to be weak. The bosonic aspects in the Hoyle state, therefore, are predominant. It is conjectured that $\\alpha$-particle condensate states also exist in heavier $n\\alpha$ nuclei, like $^{16}$O, $^{20}$Ne, etc. For instance the $0^+_6$ state of $^{16}$O at $E_{x}=15.1$ MeV is identified from a theoretical analysis as being a strong candidate of a $4\\alpha$ condensate. The calculated small width (34 keV) of $0^+_6$, consistent with data, lends credit to the existence of heavier Hoyle-analogue states. In non-self-conjugated nuclei such as $^{11}$B and $^{13}$C, we discuss candidates for the product states of clusters, composed of $\\alpha$'s, triton's, and neutrons etc. The relationship of $\\alpha$-particle condensation in finite nuclei to quartetting in symmetric nuclear matter is investigated with the help of an in-medium modified four-nucleon equation. A nonlinear order parameter equation for quartet condensation is derived and solved for $\\alpha$ particle condensation in infinite nuclear matter. The strong qualitative difference with the pairing case is pointed out.

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

2011-03-21

97

Alpha particle confinement in tokamaks  

SciTech Connect

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

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

1988-11-01

98

ISS Update: Alpha Magnetic Spectrometer  

NASA Video Gallery

NASA Public Affairs Officer Kelly Humphries interviews Trent Martin, Johnson Space Center project manager for the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station. Questions...

99

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

ERIC Educational Resources Information Center

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

Green, Samuel B.; Yang, Yanyun

2009-01-01

100

Musical Genre Classification VIA Generalized Gaussian and Alpha-Stable Modeling  

Microsoft Academic Search

This paper describes a novel methodology for automatic musical genre classification based on a feature extraction\\/statistical similarity measurement approach. First, we perform a 1-D wavelet decomposition of the music signal and we model the resulting subband coefficients using the generalized Gaussian density (GGD) and the alpha-stable distribution. Subsequently, the GGD and alpha-stable distribution parameters are estimated during the feature extraction

C. Tzagkarakis; A. Mouchtaris; P. Tsakalides

2006-01-01

101

The escape of Lyman-alpha radiation from a multiphase interstellar medium  

Microsoft Academic Search

The Eddington approximation is used to model the transfer of radiation within a multiphase scattering medium. An estimate is thereby derived for the fraction of H Ly-alpha photons that escape from a galaxy with a two-phase interstellar medium in which dusty gas clouds lie embedded within an intercloud medium of negligible absorption and scattering coefficients. Under suitable conditions, Ly-alpha photons

David A. Neufeld

1991-01-01

102

Errors in Lattice Extractions of alpha_s Due to Use of Unphysical Pion Masses  

E-print Network

We investigate the errors due to the use of unphysical values of light quark masses in lattice extractions of $\\alpha_s$. A functional form for the pion mass dependence of the quarkonium mass splittings ($\\Delta m$) is given as an expansion in $m_\\pi/(4\\pi f_\\pi)$ and $m_\\pi r_B$, where $r_B$ is the quarkonium Bohr radius. We find that, to lowest order,$\\Delta m\\simeq A+B m_\\pi^2$, where the scale of $B$ is given by $f_\\pi^2 r_B^3$. To order $m_\\pi^4$ there are four unknown coefficients, however, utilizing multipole and operator product expansions, symmetry arguments eliminate one of the four unknowns. Using the central values for the lattice spacings which were extracted using two different, unphysical values for the pion mass, we find that the errors introduced by extrapolating to the physical regime are comparable to the errors quoted due to other sources. Extrapolation to physical values of the pion mass {\\it increases} the value of $\\alpha_s(M_Z)$, bringing its value closer to the high energy extractions.

Benjamin Grinstein; I. Z. Rothstein

1996-05-09

103

Relationship between direct and converse flexoelectric coefficients  

NASA Astrophysics Data System (ADS)

Flexoelectric effect, as a universal electromechanical coupling, has drawn lots of interests in dielectric materials. However, due to the restrictions of present measurement techniques, only part of coefficients has been experimentally examined. In this study, we derived the coordinate-dependent Gibbs free energy density function in the inhomogeneous spatial field to investigate the relationship between the direct and converse flexoelectric coefficients. In crystalline mediums and systems, the direct and converse flexoelectric coefficients are proved to equivalent according to the Maxwell relation. These results will broaden the application of the Maxwell relation into non-linear spatial field, and provide the guideline for experimental measurement and prediction of flexoelectric coefficients.

Shu, Longlong; Li, Fei; Huang, Wenbin; Wei, Xiaoyong; Yao, Xi; Jiang, Xiaoning

2014-10-01

104

Alpha-1-antitrypsin deficiency.  

PubMed

Alpha-1-antitrypsin deficiency (AATD) is a rare genetic disorder associated with the development of liver and lung disease. AAT is a 52-kD glycoprotein, produced mainly by hepatocytes and secreted into the blood. Agglomeration of the AAT-protein in hepatocytes can result in liver disease. Exposure to smoke is the major risk factor for the development of lung disease characterised as early chronic obstructive lung disease (COPD). Diagnosis is based on the analysis of the AAT genotype and phenotype. The measurement of the AAT serum level is useful as screening test. Liver biopsy is not necessary to establish the diagnosis. Therapy for AAT-related liver disease is supportive, a specific therapy is not available. AATD is a rare condition (1:5000-10000) and, as a consequence, data and information on diagnosis and treatment are not easily accessible. This chapter provides a comprehensive overview on AATD, covering basic biology, diagnostic and therapeutic approaches. PMID:20955965

Bals, Robert

2010-10-01

105

Alpha glucosidase inhibitors.  

PubMed

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

Kalra, Sanjay

2014-04-01

106

Live! From 2-Alpha  

NSDL National Science Digital Library

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

107

Generation of K{sub {alpha}} radiation by high-efficiency laser targets  

SciTech Connect

The intensity of K{sub {alpha}} radiation emanating from transversely limited thin laser targets with a periodic relief superposed onto its front side was calculated. The relief parameters and the geometrical target dimensions were optimised with the help of an analytic model. The optimal target was shown to possess a nearly 100% absorption coefficient for laser radiation and a high (up to 10{sup -3}) coefficient of laser radiation conversion to the X-ray K{sub {alpha}} radiation. (interaction of laser radiation with matter. laser plasma)

Andreev, A A; Platonov, Konstantin Yu [Federal State Unitary Enterprise All-Russian Scientific Center 'S.I.Vavilov State Optical Institute' (FSUE GOI), St.Petersburg (Russian Federation)

2011-06-30

108

The thermal expansion coefficient and Gruneisen parameter of InP crystal at low temperatures  

Microsoft Academic Search

The thermal expansion of the lattice constant of InP crystal has been measured in the range 4.2-300 K by the Bond method and the results are shown graphically. The thermal expansion coefficient alpha calculated from the experimental results is negative between 15 and 80 K and positive below 15 K. The corresponding Gruneisen parameter gamma closely follows the behaviour of

K. Haruna; H. Maeta; K. Ohashi; T. Koike

1987-01-01

109

Gross alpha analytical modifications that improve wastewater treatment compliance  

SciTech Connect

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

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

2007-07-01

110

Gas phase hydrogen permeation in alpha titanium and carbon steels  

NASA Technical Reports Server (NTRS)

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

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

1980-01-01

111

EEG Alpha Power and Intelligence.  

ERIC Educational Resources Information Center

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

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

2002-01-01

112

ORNL ALPHA MIS programmer's manual  

SciTech Connect

This manual is a reference tool for programmers who are responsible for the software maintenance of the ALPHA system user interface program, also called simply ALPHA. This ALPHA user program is a part of the overall ALPHA Management Information System (MIS), which is a general-purpose MIS. The ALPHA user interface program provides the ALPHA MIS with a user-friendly, interactive interface between the general user and the System 1022 (trademark of Software House) data base. Through this facility the general user is able to choose a data base, select records from the data base, sort those records, and display in a variety of ways useful information contained in those records. User friendliness is supported by an extensive HELP facility. This manual documents all source code necessary for the successful compilation of the ALPHA user program (version 3-A). Also included is documentation covering the external files and common blocks necessary for the successful compilation of this program as well as the system reference file, which drives the program after it is compiled. Data base external files and tables that may be accessed by the ALPHA user program are documented elsewhere.

Haese, R.L.; Smith, S.E.; Lovin, J.K.; Grubb, J.W.

1984-08-01

113

Friction Coefficient for Quarks in Supergravity Duals  

E-print Network

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

E. Antonyan

2006-11-22

114

APPENDIX C Partition Coefficients For Cadmium  

E-print Network

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

115

Thermal Expansion and Diffusion Coefficients of Carbon  

E-print Network

Thermal Expansion and Diffusion Coefficients of Carbon Nanotube-Polymer Composites Chenyu Wei* NASA for polymer-nanotube interface are used to investigate the thermal expansion and diffusion characteristics to increase the glass transition temperature Tg, and thermal expansion and diffusion coefficients

Wei, Chenyu

116

A pattern fit coefficient for water application  

Microsoft Academic Search

A new coefficient, the pattern fit coefficient for water application, Pa, is introduced. It expresses the differences between an applied and any predetermined water pattern. The efficiency of many irrigation systems and methods are evaluated by comparing them to a uniform pattern. In several cases, however, strip patterns are more efficient and, therefore, preferred (e.g. small row crops, early growing

Victor Alchanatis; Ilan Amir

1990-01-01

117

Optimization of Transform Coefficients via Genetic Algorithm  

E-print Network

Optimization of Transform Coefficients via Genetic Algorithm Steven Becke CS 470 ­Project Write.................................................................................................................... 22 #12;1 Optimization of Transform Coefficients via Genetic Algorithm Steven Becke Abstract discovered in recent years for image compression is Wavelet Transforms. Wavelet transforms can dramatically

Mock, Kenrick

118

The assembly and organization of the alpha 5 and alpha 7 helices from the pore-forming domain of Bacillus thuringiensis delta-endotoxin. Relevance to a functional model.  

PubMed

The pore-forming domain of Bacillus thuringiensis insecticidal CryIIIA delta-endotoxin contains two helices, alpha 5 and alpha 7, that are highly conserved within all different Cry delta-endotoxins. To gain information on the mode of action of delta-endotoxins, we have used a spectrofluorimetric approach and characterized the structure, the organization state, and the ability to self-assemble and to co-assemble within lipid membranes of alpha 5 and alpha 7. Circular dichroism (CD) spectroscopy revealed that alpha 7 adopts a predominantly alpha-helical structure in methanol, similar to what has been found for alpha 5, and consistent with its structure in the intact molecule. The hydrophobic moment of alpha 7 is higher than that calculated for alpha 5; however, alpha 7 has a lesser ability to permeate phospholipids as compared to alpha 5. Binding experiments with 7-nitrobenz-2-oxa-1,3-diazole-4-yl (NBD)-labeled peptide demonstrated that alpha 7 binds to phospholipid vesicles with a partition coefficient in the order of 10(4) M-1 similar to alpha 5, but with reduced kinetics and in a noncooperative manner, as opposed to the fast kinetics and cooperativity found with alpha 5. Resonance energy transfer measurements between fluorescently labeled pairs of donor (NBD)/acceptor (rhodamine) peptides revealed that, in their membrane-bound state, alpha 5 self-associates but alpha 7 does not, and that alpha 5 coassembles with alpha 7 but not with an unrelated membrane bound alpha-helical peptide. Furthermore, resonance energy transfer experiments, using alpha 5 segments, specifically labeled in either the N- or C-terminal sides, suggest a parallel organization of alpha 5 monomers within the membranes. Taken together the results are consistent with an umbrella model suggested for the pore forming activity of delta-endotoxin (Li, J., Caroll, J., and Ellar, D. J. (1991) Nature 353, 815-821), where alpha 5 has transmembrane localization and may be part of the pore lining segment(s) while alpha 7 may serve as a binding sensor that initiates the binding of the pore domain to the membrane. PMID:7852320

Gazit, E; Shai, Y

1995-02-10

119

SAR image denoising based on alpha-stable distribution and Bayesian wavelet shrinkage  

NASA Astrophysics Data System (ADS)

In this paper, an algorithm for synthetic aperture radar (SAR) image denoising in the wavelet domain is presented. The alpha-stable distribution is applied to model the wavelet coefficients of the logarithmically transformed SAR images and the Gaussian mixture model to represent the Speckle. The method of regression-type is used to estimate the four parameters of the alpha-stable distribution and EM algorithm to estimate the variance of the noise respectively. Since the alpha-stable distribution do not always have a closed-form formula, Zolotarev's (M) parameterization is exploited to obtain the probability density function (PDF) of the alpha-stable distribution. Consequently, a maximum a posteriori (MAP) estimator is designed based on the alpha-stable prior to restore the SAR image. The experimental results, including simulated SAR image and SIR-C/X-band SAR image, indicate that the proposed algorithm has capability both in Speckle suppression and details preservation.

Xu, Xin; Zhao, Yin; Zhou, Wanbin; Peng, Yijin

2009-10-01

120

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

PubMed

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

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

2014-03-01

121

An agreement coefficient for image comparison  

USGS Publications Warehouse

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

Ji, L.; Gallo, K.

2006-01-01

122

How Is Alpha-1 Antitrypsin Deficiency Diagnosed?  

MedlinePLUS

... from the NHLBI on Twitter. How Is Alpha-1 Antitrypsin Deficiency Diagnosed? Alpha-1 antitrypsin (AAT) deficiency usually is diagnosed after you ... how severe it is. Rate This Content: Alpha-1 Antitrypsin Deficiency Clinical Trials Clinical trials are research ...

123

What Is Alpha-1 Antitrypsin Deficiency?  

MedlinePLUS

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

124

Genetics Home Reference: Alpha-1 antitrypsin deficiency  

MedlinePLUS

... Research studies OMIM Genetic disorder catalog Conditions > Alpha-1 antitrypsin deficiency On this page: Description Genetic changes ... Glossary definitions Reviewed January 2013 What is alpha-1 antitrypsin deficiency? Alpha-1 antitrypsin deficiency is an ...

125

[Alpha-1-antitrypsin deficiency].  

PubMed

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

Bouchecareilh, Marion

2014-10-01

126

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

PubMed Central

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

Cheng, En; Ozsoyoglu, Z. Meral

2014-01-01

127

Modeling satellite drag coefficients with response surfaces  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

128

Mass spectral identification of the metabolites of alpha,alpha-dimethyl-4-(alpha,alpha,beta,beta-tetrafluorophenethyl)-benzylamine (MK-251), a novel antiarrhythmic agent, in various species.  

PubMed

The identification of a number of metabolites of the novel antiarrhythmic agent, alpha,alpha-dimethyl-4-(alpha,alpha,beta,beta-tetrafluorophenethyl)benzylamine (MK-251), is presented. The compound is extensively metabolized by dog, monkey, baboon and man. Similar metabolic profiles were obtained for all species. Isolation and purification were accomplished by solvent extraction and chromatographic (column, gas and thin-layer) procedures. Gas chromatography, derivatization, infrared, nuclear magnetic resonance and particularly combined gas chromatography low and high resolution mass spectrometry techniques were employed to characterize the metabolites. The major urinary and plasma metabolites were identified as 2-[4-(alpha,alpha,beta,beta-tetrafluorophenethyl)phenyl]-2-propanol and its glucuronide conjugate. Other metabolites characterized were: the N-glucuronide of MK-251; 2-[4-(alpha,alpha,beta,beta-tetrafluorophenethyl)phenyl]propene; 2-nitro-2-[4-)alpha,alpha,beta,beta-tetrafluorophenethyl)phenyl]propane; alpha,alpha-dimethyl-4(alpha,alpha,beta,beta-tetrafluorophenethyl)benzyl methyl ether; and 4-(alpha,alpha,beta,beta-tetrafluorophenethyl)acetophenone. The 0-methyl ether metabolite represents the first instance of in vivo alkylation of a tertiary alcohol. Tentative identification was made for the N-hydroxy analog of MK-251 and for the glycol analog of 2-[4-(alpha,alpha,beta,beta-tetrafluorophenethyl)phenyl]-2-propanol. The observed pharmacological response appears to result mainly from MK-251 and not from the four metabolites. PMID:826289

Zacchei, A G; Rhodes, R E; Christy, M E

1976-12-01

129

Alpha-particle spectrometer experiment  

NASA Technical Reports Server (NTRS)

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

Gorenstein, P.; Bjorkholm, P.

1972-01-01

130

Dependence of dispersion coefficients on atomic environment  

NASA Astrophysics Data System (ADS)

Addition of a dispersion-energy correction to density-functional theory significantly improves potential-energy curves for dispersion-bound complexes. The exchange-hole dipole moment (XDM) model allows non-empirical calculation of atomic and molecular dispersion coefficients using only occupied orbitals and polarizabilities. In this work, the XDM model is applied to examine the dependence of dispersion coefficients on changes in atomic environment, such as charge, oxidation state, and hybridization. The variations in dispersion coefficients, and resulting energy contributions, are assessed for selected chemical examples.

Johnson, Erin R.

2011-12-01

131

Diffuse reflection coefficient of a stratified sea.  

PubMed

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

Haltrin, V I

1999-02-20

132

Generalized Coefficients for Hopf Cyclic Cohomology  

NASA Astrophysics Data System (ADS)

A category of coefficients for Hopf cyclic cohomology is defined. It is shown that this category has two proper subcategories of which the smallest one is the known category of stable anti Yetter-Drinfeld modules. The middle subcategory is comprised of those coefficients which satisfy a generalized SAYD condition depending on both the Hopf algebra and the (co)algebra in question. Some examples are introduced to show that these three categories are different. It is shown that all components of Hopf cyclic cohomology work well with the new coefficients we have defined.

Hassanzadeh, Mohammad; Kucerovsky, Dan; Rangipour, Bahram

2014-09-01

133

On the emission coefficient of uranium plasmas.  

NASA Technical Reports Server (NTRS)

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

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

1973-01-01

134

Probability density of the empirical wavelet coefficients of a noisy chaos  

NASA Astrophysics Data System (ADS)

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

Garcin, Matthieu; Guégan, Dominique

2014-05-01

135

MITOSIS RECURSION FOR COEFFICIENTS OF SCHUBERT POLYNOMIALS  

E-print Network

MITOSIS RECURSION FOR COEFFICIENTS OF SCHUBERT POLYNOMIALS EZRA MILLER Abstract.Mitosis is a rule introduced in [KM02a] for manipulating subsets proof of these properties of mitosis. 1. Introduction It has been

Miller, Ezra N.

136

Determination of diffusion coefficient for unsaturated soils  

E-print Network

. The laboratory procedure followed involves measuring the soil suction along the length of the sample and at different times using thermocouple psychrometers. The evaluation of the evaporation coefficient (he) has been made an integral part of the procedure...

Sood, Eeshani

2005-08-29

137

Creating materials with a desired refraction coefficient  

E-print Network

A method is given for creating material with a desired refraction coefficient. The method consists of embedding into a material with known refraction coefficient many small particles of size $a$. The number of particles per unit volume around any point is prescribed, the distance between neighboring particles is $O(a^{\\frac{2-\\kappa}{3}})$ as $a\\to 0$, $0<\\kappa<1$ is a fixed parameter. The total number of the embedded particle is $O(a^{\\kappa-2})$. The physical properties of the particles are described by the boundary impedance $\\zeta_m$ of the $m-th$ particle, $\\zeta_m=O(a^{-\\kappa})$ as $a\\to 0$. The refraction coefficient is the coefficient $n^2(x)$ in the wave equation $[\

A. G. Ramm

2009-09-02

138

Synthesis and herbicidal activity of novel alpha,alpha,alpha-trifluoro-m-tolyl pyridazinone derivatives.  

PubMed

A series of novel alpha,alpha,alpha-trifluoro-m-tolyl pyridazinone derivatives was synthesised. Herbicidal activities of the two intermediate compounds and 15 pyridazinone derivatives were evaluated through barnyardgrass and rape cup tests and Spirodela polyrrhiza (L.) Schleiden tests. Selected compounds were also evaluated under greenhouse conditions. Bleaching activities were observed at 10 microg ml(-1) and some compounds exhibited herbicidal activities at a rate of 300 g ha(-1). The relationship between crystal structures and herbicidal activities is discussed through a comparison of two compounds (5a and 5f). PMID:16602079

Xu, Han; Zou, Xiao-Mao; Zhu, You-Quan; Liu, Bin; Tao, Han-Lin; Hu, Xu-Hong; Song, Hai-Bin; Hu, Fang-Zhong; Wang, Yong; Yang, Hua-Zheng

2006-06-01

139

Diffusion coefficients for fast reactor hexagonal assemblies  

SciTech Connect

A consistent model for the calculation of fast reactor assembly diffusion coefficients is presented. Allowance is made for the treatment of both sodiumfilled and sodium-voided lattices, with the same approximation applied, which is essential for the study of the sodium-voiding effect. The hexagonal steel tube is also taken into account. The formalism is implemented in the ASDIC (Assembly Diffusion Coefficients) program. Numerical results and comparisons with results of other models are given.

Benoist, P.; Duracz, T.

1984-05-01

140

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

Microsoft Academic Search

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

Alexia Briassouli; Panagiotis Tsakalides; Athanasios Stouraitis

2005-01-01

141

Self-consistent modeling of the flow behavior of wrought alpha\\/beta titanium alloys under isothermal and nonisothermal hot-working conditions  

Microsoft Academic Search

A self-consistent model was applied to predict the plastic flow behavior during hot working of alpha\\/beta titanium alloys\\u000a with wrought (equiaxed alpha) microstructures as a function of the flow behavior and volume fractions of the individual phases.\\u000a For this purpose, constitutive relations that incorporated composition-dependent strength coefficients were determined for\\u000a the alpha and beta phases. With these constitutive relations and

S. L. Semiatin; F. Montheillet; G. Shen; J. J. Jonas

2002-01-01

142

Binding of actin to lens alpha crystallins  

NASA Technical Reports Server (NTRS)

Actin has been coupled to a cyanogen bromide-activated Sepharose 4B column, then tested for binding to alpha, beta, and gamma crystallin preparations from the bovine lens. Alpha, but not beta or gamma, crystallins bound to the actin affinity column in a time dependent and saturable manner. Subfractionation of the alpha crystallin preparation into the alpha-A and alpha-B species, followed by incubation with the affinity column, demonstrated that both species bound approximately the same. Together, these studies demonstrate a specific and saturable binding of lens alpha-A and alpha-B with actin.

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

1992-01-01

143

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

ERIC Educational Resources Information Center

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

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

2012-01-01

144

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

E-print Network

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

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

2014-05-23

145

Alpha-muon sticking and chaos in muon-catalysed "in flight" d-t fusion  

E-print Network

We discuss the alpha-muon sticking coefficient in the muon-catalysed ``in flight" d-t fusion in the framework of the Constrained Molecular Dynamics model. Especially the influence of muonic chaotic dynamics on the sticking coefficient is brought into focus. The chaotic motion of the muon affects not only the fusion cross section but also the $\\mu-\\alpha$ sticking coefficient. Chaotic systems lead to larger enhancements with respect to regular systems because of the reduction of the tunneling region. Moreover they give smaller sticking probabilities than those of regular events. By utilizing a characteristic of the chaotic dynamics one can avoid losing the muon in the $\\mu$CF cycle. We propose the application of the so-called ``microwave ionization of a Rydberg atom" to the present case which could lead to the enhancement of the reactivation process by using X-rays.

Sachie Kimura; Aldo Bonasera

2006-05-24

146

Understanding correlation coefficients in treaty verification  

SciTech Connect

When a pair of images are compared on a point-by-point basis, the linear-correlation coefficient is usually used as a measure of similarity or dissimilarity. This paper evaluates the theoretical underpinnings and limitation of the linear-correlation coefficient, as well as other related statistics, particularly for cases where inherent white noise is present. As a result of the limitations in linear-correlation, an additional step has been derived -- local-sum clustering -- in order to improve recognition of small dissimilarities in a pair images. Results show that three-stage procedure, consisting of first establishing congruence of the two images, than using the linear-correlation coefficient as a test of true negatives, and finally qualifying a true positive by using the cluster (local-sum) method. These algorithmic stages would be especially useful in arms control treaty verification.

DeVolpi, A.

1991-11-01

147

Diffusion coefficients in leaflets of bilayer membranes  

E-print Network

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

Kazuhiko Seki; Saurabh Mogre; Shigeyuki Komura

2014-02-05

148

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

SciTech Connect

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

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

2007-10-02

149

Converting gravity bins to spherical harmonic coefficients  

NASA Technical Reports Server (NTRS)

The gravity bin technique as originally formulated recovers the local gravity field from the bin parameters by finite differencing. The spherical harmonic coefficients of the gravity field are then computed by an orthogonal transformation of the local gravity field. The result differs from that of the traditional method. This paper discusses the difference and proposes a new algorithm to convert the bin parameters to spherical harmonic coefficients. It is shown that the new method produces the same gravity field as the traditional method and maintains the high computational efficiency of the basic gravity bin technique.

Wu, J. T.; Bertiger, W. I.; Wu, S. C.

1990-01-01

150

Fractal diffusion coefficient from dynamical zeta functions  

E-print Network

Dynamical zeta functions provide a powerful method to analyze low dimensional dynamical systems when the underlying symbolic dynamics is under control. On the other hand even simple one dimensional maps can show an intricate structure of the grammar rules that may lead to a non smooth dependence of global observable on parameters changes. A paradigmatic example is the fractal diffusion coefficient arising in a simple piecewise linear one dimensional map of the real line. Using the Baladi-Ruelle generalization of the Milnor-Thurnston kneading determinant we provide the exact dynamical zeta function for such a map and compute the diffusion coefficient from its smallest zero.

G. Cristadoro

2005-09-28

151

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

PubMed

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

He, Yong; Cheng, Weimin; Cai, Hesheng

2005-04-11

152

Cyclic voltammetric study of alpha-methyldopa at carbon paste electrode.  

PubMed

The cyclic voltammetric behaviour of alpha-methyldopa at a silicon oil carbon paste electrode has been reported. This allowed the development of a quantitative method to determine alpha-methyldopa in LiCl, KCl, NaCl, HCl, H2SO4 and CH3COOH as supporting electrolytes. For qualitative characteristics, alpha-methyldopa showed an ECC mechanism in terms of electron transfer reaction (placing it in DPI zone) at carbon paste electrode. The values of transfer coefficients alpha and beta were determined. The larger DeltaEp values were obtained due to the use of unmodified carbon paste electrode (CPE) has decreased the rate of electron transfer at the surface of the test electrode. The first order rate constant values (ko) were within 0.10-7.78 +/- 0.1x10(-3) s(-1). Adsorption of analyte was also determined at CPE using repeated scan method. PMID:16431377

Ali, S Azhar; Sami, M A

2005-01-01

153

Alpha Centauri at a Crossroads  

NASA Astrophysics Data System (ADS)

Nearby Alpha Centauri (G2V+K1V) contains the two best characterized solar-like dwarf stars, which also have the best studied X-ray activity cycles, extending back to the 1970's. Objective is to continue tracking the evolving multi-decadal high-energy narrative of Alpha Cen with semiannual HRC-I pointings in Cycles 16-18, as the system reaches a coronal crossroads: solar twin A rising toward cycle maximum, K-type companion B sinking into a minimum. HST/STIS UV spectra will support and leverage the X-ray measurements by probing subcoronal dynamics, with connection to the corona through the FUV Fe XII forbidden line. Only Chandra can resolve the AB X-ray sources as the Alpha Cen orbit also reaches a crossroads in 2016.

Ayres, Thomas

2014-09-01

154

Space Station alpha joint bearing  

NASA Technical Reports Server (NTRS)

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

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

1987-01-01

155

Bremsstrahlung in {alpha} Decay Reexamined  

SciTech Connect

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

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

2007-07-13

156

Bremsstrahlung in alpha decay reexamined.  

PubMed

A high-statistics measurement of bremsstrahlung emitted in the alpha decay of (210)Po has been performed, which allows us to follow the photon spectra up to energies of approximately 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. PMID:17678219

Boie, H; Scheit, H; Jentschura, U D; Köck, F; Lauer, M; Milstein, A I; Terekhov, I S; Schwalm, D

2007-07-13

157

Measurements of dissociative recombination coefficients of H3(+), HCO(+), N2H(+), and CH5(+) at 95 and 300 K using the FALP apparatus  

NASA Astrophysics Data System (ADS)

Flowing afterglow/Langmuir probe technique has been used to determine dissociative recombination coefficients alpha(t) at 95 and 300 K for the important interstellar ions H3(+), D3(+), N2HD(+), HCO(+), DCO(+), and CH5(+). Contrary to previous stationary afterglow (SA) studies, alpha(t) for h3(+) was found to be immeasurably small at both temperatures, a result which is consistent with recent theoretical predictions. At 300 K, alpha(t) for HCO(+) is 1.1(-7) cu cm/s and alpha(t) for N2H(+) is 1.7(-7) cu cm/s; both were larger by a factor of three at 95 K. Alpha(t) for CH5(+) is 1.1(-6) cu cm/s at 300 K and 1.5(-6) cu cm/s at 95 K. The alpha(t) data for HCO(+) are compared with previous SA data and the alpha(t) data for N2H(+) and CH5(+) are discussed in relation to recombination coefficients derived from merged beam cross section data.

Adams, N. G.; Smith, D.; Alge, E.

1984-08-01

158

Problems on Divisibility of Binomial Coefficients  

ERIC Educational Resources Information Center

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

Osler, Thomas J.; Smoak, James

2004-01-01

159

Determination of Longitudinal Dispersion Coefficient and Net  

E-print Network

Determination of Longitudinal Dispersion Coefficient and Net Advection in the Tidal Hudson River in the tidal Hudson River to examine longitudinal dispersion and net advection. SF6 was injected into the Hudson River near Newburgh, NY, and surveyed for 13 days using a new, fully automated, high-resolution SF

Ho, David

160

Variational principles for relativistic transport coefficients  

Microsoft Academic Search

Variational expressions for the transport coefficients of a one-component, relativistic gas are derived from the linearized relativistic Boltzmann equation for both quantum and classical gases. These expressions depend on functions chi of the energy of the particles comprising the gas in such a way that (1) if chi differs from a solution of the linearized Boltzmann equation by epsilon, then

J. L. Anderson

1975-01-01

161

Net emission coefficient of air thermal plasmas  

Microsoft Academic Search

We have calculated the net emission coefficient of air plasmas at atmospheric pressure in the temperature range between 300 and 40 000 K, in the assumption of local thermodynamic equilibrium and isothermal plasmas. This calculation takes into account the radiation due to the atomic continuum, the molecular continuum, the molecular bands (several systems for O2, N2, NO and N2+) and

Y Naghizadeh-Kashani; Y Cressault; A Gleizes

2002-01-01

162

Mel Frequency Cepstral Coefficients for Music Modeling  

Microsoft Academic Search

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

Beth Logan

2000-01-01

163

Coefficient Omega Bootstrap Confidence Intervals: Nonnormal Distributions  

ERIC Educational Resources Information Center

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

Padilla, Miguel A.; Divers, Jasmin

2013-01-01

164

EXAMINATION OF SCALE-DEPENDENT DISPERSION COEFFICIENTS  

EPA Science Inventory

Many hydrologists have observed that dispersion coefficients, when measured in the field, turn out to be scale-dependent. Recently, Guven, et al., (1983) presented a study which contains a basis for understanding the phenomenon of scale-dependent dispersion within a deterministic...

165

Transpiration coefficients for three Great Basin shrubs  

Microsoft Academic Search

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

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

2001-01-01

166

Canonical Definition of Wigner Coefficients in Un  

Microsoft Academic Search

Two general results applicable to the problem of a canonical definition of the Wigner coefficient in Un are demonstrated: (1) the existence of a canonical imbedding of Un × Un into Un2 and (2) a general factorization lemma for operators defined in the boson calculus. Using these results, a resolution of the multiplicity problem for U3 is demonstrated, in which

L. C. Biedenharn; A. Giovannini; J. D. Louck

1967-01-01

167

Research on the dynamic coefficient of logistics  

Microsoft Academic Search

Based on the thoughts of analogy and with reference to the natural phenomena of the water, air and electronic currents, the paper analyses the socio- economic phenomenon—logistics. It first analyses the influential factors of the formation of logistics and then respectively establishes the dynamic coefficients and the dynamic equations of business and military logistics, trying to reveal the law of

Jin Xiuman; Jin Feng

2011-01-01

168

The effect of thermal cycling to 1100 C on the alpha /Mo/ phase in directionally solidified gamma/gamma-prime-alpha alloys  

NASA Technical Reports Server (NTRS)

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.

Harf, F. H.

1981-01-01

169

Pyroelectric coefficient manipulation in doped TGS crystals  

NASA Astrophysics Data System (ADS)

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

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

2006-10-01

170

Alpha-nucleus potential for alpha-decay and sub-barrier fusion  

E-print Network

The set of parameters for alpha-nucleus potential is derived by using the data for both the alpha-decay half-lives and the fusion cross-sections around the barrier for reactions alpha+40Ca, alpha+59Co, alpha+208Pb. The alpha-decay half-lives are obtained in the framework of a cluster model using the WKB approximation. The evaluated alpha-decay half-lives and the fusion cross-sections agreed well with the data. Fusion reactions between alpha-particle and heavy nuclei can be used for both the formation of very heavy nuclei and spectroscopic studies of the formed compound nuclei.

V. Yu. Denisov; H. Ikezoe

2005-10-27

171

Measuring correlations between non-stationary series with DCCA coefficient  

NASA Astrophysics Data System (ADS)

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

Kristoufek, Ladislav

2014-05-01

172

Crosslinking of alpha 2-antiplasmin to fibrin.  

PubMed

Human alpha 2-antiplasmin (alpha 2AP) is the primary inhibitor of plasmin-mediated fibrinolysis and is an efficient substrate of activated factor XIII (FXIIIa). Among 452 amino acid residues in alpha 2AP, Gln2 is believed to be the sole FXIIIa-reactive site that participates in crosslinking alpha 2AP to fibrin. We studied the effect of mutating Gln2 on the ability of FXIIIa to catalyze crosslinking of alpha 2AP to fibrin. By FXIIIa catalysis, [14C]methylamine was incorporated into a Q2A-alpha 2AP mutant in which Gln2 (Q) was replaced by Ala (A), thereby indicating that wildtype alpha 2AP has more than one FXIIIa-reactive site. To identify the FXIIIa-reactive sites in alpha 2AP, wildtype alpha 2AP and Q2A-alpha 2AP were labeled with 5-(biotinamido)pentylamine by FXIIIa. Each labeled alpha 2AP was digested with trypsin and applied to an avidin affinity column to capture labeled peptides. Edman sequencing and mass analysis of each labeled peptide showed that out of 35 Gln residues in wildtype alpha 2AP, four were labeled with the following order of efficiency: Gln2 > Gln21 > Gln419 > Gln447. Q2A-alpha 2AP was also labeled at the three minor sites, Gln21 > Gln419 > Gln447. Q2A-alpha 2AP became crosslinked to fibirin(ogen) by FXIIIa catalysis at approximately one-tenth the rate of wt-alpha 2AP. These results demonstrate that alpha 2AP has one primary (Gln2) and three minor substrate sites for FXIIIa and that the three minor sites identified in this study can also participate in crosslink formation between alpha 2AP and fibrin, but at a much lower efficiency than the Gln2 site. PMID:11460490

Lee, K N; Lee, C S; Tae, W C; Jackson, K W; Christiansen, V J; McKee, P A

2001-01-01

173

Confined Nonthermal Alpha Distribution and Transport Measurements in D-T Plasmas on Tftr  

NASA Astrophysics Data System (ADS)

A high sensitivity diagnostic system has been developed to provide the first observation of confined nonthermal alpha particles produced in a reactor-grade deuterium-tritium (D-T) fusion plasma. These absolutely calibrated measurements of the energy distribution and spatial profiles have allowed testing of fast alpha slowing -down models and determination of fast alpha cross-field transport. The new alpha-CHERS diagnostic is a charge exchange recombination spectroscopy (CHERS) system specifically designed to observe the Doppler-shifted n = 4-3 transition of He^{+1} near lambda_{o } = 468.6 nm. The intensity of the fast alpha spectral feature is less than 1% of the bremsstrahlung continuum background, and its measurement requires greater than 100 times more light throughput than previous CHERS diagnostics. The required sensitivity is achieved with high throughput optics and high-quantum-efficiency, high -dynamic-range low-noise detectors. Analysis techniques are developed to allow extraction of the photon-noise-limited alpha signal from the continuum background and impurity emissions. These results demonstrate the small signal extraction methods required for active beam spectroscopy measurements of ion temperature, impurity density, plasma rotation, and current density in large, high-density plasmas in future reactors such as ITER. Spatial, temporal and energy-resolved measurements of the alpha distribution for E_{alpha }<=q 0.7 MeV have been obtained in D -T plasmas on the Tokamak Fusion Test Reactor (TFTR). During a sawtooth-free discharge, the measured alpha energy spectrum is in good agreement with that predicted on the basis of neoclassical transport. Time-resolved measurements during the alpha thermalization period after alpha source turn -off show decay of the distribution function to lower energies consistent with the classical slowing-down time of about 0.5 sec. Radial profiles are best characterized by a slowing -down alpha distribution subject to neoclassical plus a small anomalous cross-field diffusion with an effective anomalous diffusion coefficient in the range D _{alpha,a} = 0.00 -0.03 m^2/s, well below the previous upper limit of 0.1 m^2/s determined from fast ion measurements. In addition, sawtooth redistribution of core alphas is observed.

McKee, George Raymond, Jr.

174

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

NASA Technical Reports Server (NTRS)

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

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

1996-01-01

175

Temperature dependence of electron and hole ionization coefficients in InP  

SciTech Connect

In this work the authors investigate the temperature dependence of the electron and hole ionization coefficients in <100> Indium Phosphide, in a wide range, from 50 K to room temperature. They use InP/InGaAs p{sup +}n junctions to accurately measure the dependence of the breakdown voltage on the temperature. From the data measured during the fabrication processing, the authors evaluate the doping profiles and the depths of the various layers. Then they compute the electric field in the high field region. In order to take into account the dependence of the ionization coefficients on both the electric field and the temperature, the authors use a reported physical model. By adjusting the only fitting parameter, they obtain the complete expressions for {alpha}(E,T) and {beta}(E,T), that herewith they report, and that are in good agreement with other published data.

Zappa, F.; Lovati, P.; Lacaita, A. [Politecnico di Milano (Italy). Dept. di Elettronica e Informazione

1996-12-31

176

What Causes Alpha-1 Antitrypsin Deficiency?  

MedlinePLUS

... from the NHLBI on Twitter. What Causes Alpha-1 Antitrypsin Deficiency? Alpha-1 antitrypsin (AAT) deficiency is an inherited disease. "Inherited" ... have AAT deficiency inherit two faulty AAT genes, one from each parent. These genes tell cells in ...

177

How Is Alpha-1 Antitrypsin Deficiency Treated?  

MedlinePLUS

... from the NHLBI on Twitter. How Is Alpha-1 Antitrypsin Deficiency Treated? Alpha-1 antitrypsin (AAT) deficiency has no cure, but its ... of these treatments are the same as the ones used for a lung disease called COPD (chronic ...

178

Rotational dissipation and the Miesowicz coefficients  

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

179

Differences between charged-current coefficient functions  

NASA Astrophysics Data System (ADS)

Second- and third-order results are presented for the structure functions of charged-current deep-inelastic scattering in the framework of massless perturbative QCD. We write down the two-loop differences between the corresponding crossing-even and -odd coefficient functions, including those for the longitudinal structure function not covered in the literature so far. At three loops we compute the lowest five moments of these differences for all three structure functions and provide approximate expressions in Bjorken- x space. Also calculated is the related third-order coefficient-function correction to the Gottfried sum rule. We confirm the conjectured suppression of these quantities if the number of colours is large. Finally we derive the second- and third-order QCD contributions to the Paschos-Wolfenstein ratio used for the determination of the weak mixing angle from neutrino-nucleon deep-inelastic scattering. These contributions are found to be small.

Moch, S.; Rogal, M.; Vogt, A.

2008-02-01

180

Random matrices and Lyapunov coefficients regularity  

E-print Network

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 of dynamical systems. The method is based on the classical theory of the Mayer series in Statistical Mechanics of rarefied gases.

Giovanni Gallavotti

2013-11-20

181

Association of actin with alpha crystallins  

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

182

AlphaSort: A RISC Machine Sort  

Microsoft Academic Search

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

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

1994-01-01

183

Alpha-like calculations with MCNP  

SciTech Connect

Alpha (time-absorption eigenvalue) calculations are not an explicit calculational option in MCNP. Nevertheless, it is possible to perform alpha calculations with MCNP. Such calculations are presently either very inefficient or require special coding or cross section library modifications. However, alpha-like calculations can easily be performed with MCNP using the KCODE option with neutron energy- or time-cutoffs. These approximate alpha-like calculations are described and tested.

Parsons, D.K.

1997-11-01

184

The ultraviolet spectra of Alpha Aquilae and Alpha Canis Minoris  

NASA Technical Reports Server (NTRS)

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.

Morton, D. C.; Bruzual A., G.; Kurucz, R. L.; Spinrad, H.

1977-01-01

185

Roughness coefficients for stream channels in Arizona  

USGS Publications Warehouse

       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.

Aldridge, B. N.; Garrett, J. M.

1973-01-01

186

Edge Diffraction Coefficients around Critical Rays  

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

187

MULTIVARIATE VARYING COEFFICIENT MODEL FOR FUNCTIONAL RESPONSES  

PubMed Central

Motivated by recent work studying massive imaging data in the neuroimaging literature, we propose multivariate varying coefficient models (MVCM) for modeling the relation between multiple functional responses and a set of covariates. We develop several statistical inference procedures for MVCM and systematically study their theoretical properties. We first establish the weak convergence of the local linear estimate of coefficient functions, as well as its asymptotic bias and variance, and then we derive asymptotic bias and mean integrated squared error of smoothed individual functions and their uniform convergence rate. We establish the uniform convergence rate of the estimated covariance function of the individual functions and its associated eigenvalue and eigenfunctions. We propose a global test for linear hypotheses of varying coefficient functions, and derive its asymptotic distribution under the null hypothesis. We also propose a simultaneous confidence band for each individual effect curve. We conduct Monte Carlo simulation to examine the finite-sample performance of the proposed procedures. We apply MVCM to investigate the development of white matter diffusivities along the genu tract of the corpus callosum in a clinical study of neurodevelopment. PMID:12926711

Zhu, Hongtu; Li, Runze; Kong, Linglong

2012-01-01

188

MULTIVARIATE VARYING COEFFICIENT MODEL FOR FUNCTIONAL RESPONSES  

PubMed Central

Motivated by recent work studying massive imaging data in the neuroimaging literature, we propose multivariate varying coefficient models (MVCM) for modeling the relation between multiple functional responses and a set of covariates. We develop several statistical inference procedures for MVCM and systematically study their theoretical properties. We first establish the weak convergence of the local linear estimate of coefficient functions, as well as its asymptotic bias and variance, and then we derive asymptotic bias and mean integrated squared error of smoothed individual functions and their uniform convergence rate. We establish the uniform convergence rate of the estimated covariance function of the individual functions and its associated eigenvalue and eigenfunctions. We propose a global test for linear hypotheses of varying coefficient functions, and derive its asymptotic distribution under the null hypothesis. We also propose a simultaneous confidence band for each individual effect curve. We conduct Monte Carlo simulation to examine the finite-sample performance of the proposed procedures. We apply MVCM to investigate the development of white matter diffusivities along the genu tract of the corpus callosum in a clinical study of neurodevelopment. PMID:23645942

Zhu, Hongtu; Li, Runze; Kong, Linglong

2012-01-01

189

Understanding correlation coefficients in treaty verification. Revised  

SciTech Connect

When a pair of images is compared on a point-by-point basis, the linear-correlation coefficient is usually used as a measure of similarity or dissimilarity. This report evaluates the theoretical underpinnings and limitations of the linear-correlation coefficient, as well as other related statistics, particularly for cases where inherent white noise is present. As a result of the limitations in linear-correlation, an additional step has been derived -- local-sum clustering -- in order to improve recognition of small dissimilarities in a pair of otherwise identical images. Results show an optimal three-stage procedure: first, establish congruence of the two images; second, use the linear-correlation coefficient as a test of true negatives; and, third, qualify a true positive by using the cluster (local-sum) method. These three algorithmic stages would be especially useful in application to arms control treaty verification, particularly for comparison of unique identifiers (tags or seals). This is illustrated by comparing scanning-electron microscope topographical images for an intrinsic-surface tag.

DeVolpi, A.

1993-02-01

190

Diffusion coefficients in gravel under unsaturated conditions  

SciTech Connect

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.

Conca, J.L.; Wright, J. (Pacific Northwest Lab., Richland, WA (USA))

1990-05-01

191

`Paradoxical' alpha synchronization in a memory task  

Microsoft Academic Search

The results of a specially designed memory search paradigm which maximizes episodic short-term memory (STM) and minimizes semantic long-term memory (LTM) demands show that the upper alpha band synchronizes selectively in those conditions and time intervals where episodic STM demands are maximal. This finding of a selective alpha synchronization occurring only in the upper alpha band and during highest task

W. Klimesch; M. Doppelmayr; J. Schwaiger; P. Auinger; Th. Winkler

1999-01-01

192

Effectiveness of Alpha Biofeedback Therapy: Negative Results.  

ERIC Educational Resources Information Center

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

Watson, Charles G.; Herder, Joseph

1980-01-01

193

Atypical Alpha Asymmetry in Adults with ADHD  

ERIC Educational Resources Information Center

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

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

2009-01-01

194

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

E-print Network

A new numerical method has been developed for calculation of density second virial coefficients, B(T), from sonic velocity measurements in gases at low pressures. Unlike existing methods, this procedure requires no model assumption as to the form...

Mossaad, Ehab

2012-06-07

195

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

E-print Network

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

Smith, E; Papp, Z

2012-01-01

196

Alpha-plutonium's Grüneisen parameter.  

PubMed

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

Ledbetter, Hassel; Lawson, Andrew; Migliori, Albert

2010-04-28

197

On the equilibrium between monomeric alpha-lactalbumin and the chaperoning complex of alpha-crystallin.  

PubMed

In chaperoning dithiothreitol-denatured alpha-lactabumin, alpha-crystallin forms a chaperoning complex. In order to study the kinetics of such chaperoning it needs to be established whether the formation of the chaperoning complex is a reversible or irreversible process. The chaperoning reaction was studied by dynamic light scattering as a function of concentration and weight ratio of alpha-lactalbumin/alpha-crystallin. HPLC and subsequent SDS-PAGE gel electrophoresis experiments established that the chaperoning complex formed contains both alpha-crystallin and alpha-lactalbumin. Upon rechromatographing the chaperoning complex, the presence of monomeric alpha-lactalbumin has been demonstrated in addition to the chaperoning complex itself. This and equilibrium dialysis experiments demonstrated conclusively the existence of an equilibrium between monomeric partially denatured alpha-lactalbumin and the chaperoning complex made of alpha-lactalbumin and alpha-crystallin. PMID:11162470

Neal, R; Zigler, J S; Bettelheim, F A

2001-01-12

198

Alpha voltaic batteries and methods thereof  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

199

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

SciTech Connect

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

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

2013-03-10

200

Surfaces with adaptive radar reflection coefficients  

NASA Astrophysics Data System (ADS)

Conventional (passive) radar-absorbing materials (RAM) have been in use now for over half a century, but it is only with recent advances in conducting polymer composite materials that large-area surfaces having controllable reflection coefficients at radar frequencies have become practicable. Techniques for utilizing these new materials in re-configurable electromagnetic, or `smart', surfaces are reviewed, with due emphasis given to the problem of system integration. The discussion is complemented by modelled and measured performance data on several smart surface configurations.

Chambers, Barry

1997-10-01

201

Transmission eigenvalues for operators with constant coefficients  

E-print Network

In this paper we study the interior transmission problem and transmission eigenvalues for multiplicative perturbations of linear partial differential operator of order $\\ge 2$ with constant real coefficients. Under suitable growth conditions on the symbol of the operator and the perturbation, we show the discreteness of the set of transmission eigenvalues and derive sufficient conditions on the existence of transmission eigenvalues. We apply these techniques to the case of the biharmonic operator and the Dirac system. In the hypoelliptic case we present a connection to scattering theory.

Michael Hitrik; Katsiaryna Krupchyk; Petri Ola; Lassi Päivärinta

2010-04-28

202

Flash ADC data processing with correlation coefficients  

E-print Network

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

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

2013-12-05

203

Numerical diffraction coefficients for surface waves  

NASA Astrophysics Data System (ADS)

The numerical uniform theory of diffraction is extended to include surface waves. A method for extracting surface wave diffraction coefficients from moment method data is given and Prony's method is applied to the problem of determining surface wave propagation constants. The method is validated through comparison with the exact solution of the problem of surface wave diffraction by a truncated dielectric slab recessed in a conducting surface. Examples are given for scattering from dielectric slabs and frequency-selective surfaces and for radiation from a conformal microstrip antenna with a truncated substrate. The accuracy obtained is demonstrated by comparison with moment method calculations.

Hurst, M. P.

1993-04-01

204

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

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

205

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

SciTech Connect

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

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

2010-08-01

206

Activated neutrophils secrete stored alpha 1-antitrypsin.  

PubMed

Neutrophil elastase (NE), a potent serine protease, is stored in primary granules of neutrophils and released following neutrophil activation. Alpha-1-antitrypsin (alpha 1-AT), the major inhibitor of NE, is synthesized by mature neutrophils. In the context of the maintenance of tissue homeostasis, we hypothesized that neutrophils may be able to store alpha 1-AT, thus having it available for release concordantly with NE. Immunofluorescence and quantitative flow-cytometric studies of neutrophils and monocytes labeled with fluorescein-conjugated alpha 1-AT-antibody demonstrated larger amounts of cytoplasmic alpha 1-AT in neutrophils than in monocytes. [35S]methionine-labeling and anti-alpha 1-AT immunoprecipitation analysis showed that although both neutrophils and monocytes synthesize alpha 1-AT, the proportion of newly synthesized intracellular alpha 1-AT was much higher in neutrophils than in monocytes. Flow-cytometric analysis showed that in the presence of surface stimulation with cytochalasin B followed by formyl-methionyleucylphenylalanine (fMLP), mean intracellular alpha 1-AT was decreased in stimulated neutrophils compared with that in resting cells, suggesting that the stored alpha 1-AT was rapidly released following surface triggering. Evaluation of surface-stimulated neutrophils by [35S]methionine labeling and anti-alpha 1-AT immunoprecipitation demonstrated increased secretion of alpha 1-AT compared with that of resting neutrophils, with some of the secreted alpha 1-AT capable of forming complexes with NE. Thus, neutrophils respond to surface stimulation not only by secreting NE but also by secreting its inhibitor, alpha 1-AT, suggesting that these cells have an inherent mechanism for damping the local effects of NE, their most powerful proteolytic enzyme. PMID:8970377

Pääkkö, P; Kirby, M; du Bois, R M; Gillissen, A; Ferrans, V J; Crystal, R G

1996-12-01

207

A Wavelet Space-Scale Decomposition Analysis of Structures and Evolution of QSO LY alpha Absorption Lines  

Microsoft Academic Search

We used the discrete wavelet transform to perform a space-scale decomposition (SSD) of the Lyman alpha forest. The SSD method of identifying and measuring structure in the spatial distribution of objects is demonstrated on simulated samples. The position and strength (richness) of the identified clusters can be described by the corresponding mother function coefficients (MFC) of the wavelet transform. Using

Jesus Pando; Li-Zhi Fang

1996-01-01

208

Coefficient adaptive triangulation for strongly anisotropic problems  

SciTech Connect

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

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

1996-01-01

209

The Convergence Coefficient across Political Systems  

PubMed Central

Formal work on the electoral model often suggests that parties or candidates should locate themselves at the electoral mean. Recent research has found no evidence of such convergence. In order to explain nonconvergence, the stochastic electoral model is extended by including estimates of electoral valence. We introduce the notion of a convergence coefficient, c. It has been shown that high values of c imply that there is a significant centrifugal tendency acting on parties. We used electoral surveys to construct a stochastic valence model of the the elections in various countries. We find that the convergence coefficient varies across elections in a country, across countries with similar regimes, and across political regimes. In some countries, the centripetal tendency leads parties to converge to the electoral mean. In others the centrifugal tendency dominates and some parties locate far from the electoral mean. In particular, for countries with proportional electoral systems, namely, Israel, Turkey, and Poland, the centrifugal tendency is very high. In the majoritarian polities of the United States and Great Britain, the centrifugal tendency is very low. In anocracies, the autocrat imposes limitations on how far from the origin the opposition parties can move. PMID:24385886

Schofield, Norman

2013-01-01

210

Astrophysical S Factors from Asymptotic Normalization Coefficients  

NASA Astrophysics Data System (ADS)

Peripheral transfer reactions can be used to determine asymptotic normalization coefficients (ANC). These coefficients, which provide the normalization of the tail of the overlap function, determine S factors for direct capture reactions at astro-physical energies. A variety of proton transfer reactions have been used to measure ANC's. As tests of the technique, ANC's for 10B ? 9Be + p and 17F ? 16O + p have been measured and their values were used to predict the S factors for 9Be(p,?)10B and 16O(p,?)17F. In both cases the predictions are in excellent agreement with measured S factors. Following the same technique, the 10B(7Be,8B)9Be and 14N(7Be,8B)13C reactions have been used to measure the ANC appropriate for determining 7Be(p,?)8B. The results from the two transfer reactions provide an indirect determination of S17(0). Recent measurements have been completed on the 14N(11C,12N)13C reaction which will allow us to define the astrophysical S factor for the 11C(p,?)12N reaction.

Tribble, R. E.; Azhari, A.; Bem, P.; Burjan, V.; Carstoiu, F.; Cejpek, J.; Clark, H. L.; Gagliardi, C. A.; Kroha, V.; Lui, Y.-W.; Mukhamedzhanov, A. M.; Novak, J.; Piskor, S.; Sattarov, A.; Simeckova, E.; Tang, X.; Trache, L.; Vincour, J.

2002-01-01

211

Subtomogram alignment by adaptive Fourier coefficient thresholding  

PubMed Central

In the past few years, three-dimensional (3D) subtomogram alignment has become an important tool in cryo-electron tomography (CET). This technique allows one to resolve higher resolution structures of targets that can not be reconstructed by single-particle methods. Based on previous approaches, we present a new dissimilarity measure between subtomograms: Thresholded Constrained Cross-Correlation (TCCC). TCCC improves alignment results for low Signal-to-Noise Ratio (SNR) images (SNR < 0.1). This allows one to analyze macromolecules in thicker samples like whole cells or lower the defocus in thinner samples to push the first zero of the Contrast Transfer Function (CTF). TCCC uses statistics of the noise to automatically select only a small percentage of the Fourier coefficients to compute the cross-correlation. The thresholding has two main advantages: first, it reduces the influence of the noise; second, it avoids the missing wedge normalization problem since we consider the same amount of coefficients for all possible pairs of subtomograms. We present results in synthetic and real data and we compare them with existing methods under different SNR and missing wedge conditions. We have made our source code freely available for the community. PMID:20621702

Comolli, Luis; Moussavi, Farshid; Downing, Kenneth H.; Horowitz, Mark

2014-01-01

212

Fast computation of local correlation coefficients  

NASA Astrophysics Data System (ADS)

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

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

2008-08-01

213

On Learning Cluster Coefficient of Private Networks  

PubMed Central

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

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

2013-01-01

214

Rotordynamic coefficients for stepped labyrinth gas seals  

NASA Technical Reports Server (NTRS)

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

Scharrer, Joseph K.

1989-01-01

215

Hierarchical coefficient of a multifractal based network  

NASA Astrophysics Data System (ADS)

The hierarchical property for a general class of networks stands for a power-law relation between clustering coefficient, CC and connectivity k: CC?k?. This relation is empirically verified in several biologic and social networks, as well as in random and deterministic network models, in special for hierarchical networks. In this work we show that the hierarchical property is also present in a Lucena network. To create a Lucena network we use the dual of a multifractal lattice ML, the vertices are the sites of the ML and links are established between neighbouring lattices, therefore this network is space filling and planar. Besides a Lucena network shows a scale-free distribution of connectivity. We deduce a relation for the maximal local clustering coefficient CCimax of a vertex i in a planar graph. This condition expresses that the number of links among neighbour, N?, of a vertex i is equal to its connectivity ki, that means: N?=ki. The Lucena network fulfils the condition N??ki independent of ki and the anisotropy of ML. In addition, CCmax implies the threshold ?=1 for the hierarchical property for any scale-free planar network.

Moreira, Darlan A.; Lucena, Liacir dos Santos; Corso, Gilberto

2014-02-01

216

Characterization of alpha-phase soft proton-exchanged LiNbO3 optical waveguides.  

PubMed

Waveguides in LiNbO3 are realized by a soft proton exchange (SPE) process with use of a melt of stearic acid highly diluted by lithium stearate. No phase transitions are formed when alpha-phase waveguides are obtained by SPE. The alpha-phase presents the same crystalline structure as that of pure LiNbO3 crystal, and it maintains the excellent nonlinear and electro-optical properties of the bulk material. The kinetics of the SPE method is studied by the use of secondary-ion mass spectrometry and prism-coupling techniques. The hydrogen effective diffusion coefficient as well as the self-diffusion coefficients of H+ and Li+ ions are determined as a function of the proton-exchange temperature for X-cut LiNbO3. PMID:11336221

Korkishko, Y N; Fedorov, V A; Baranov, E A; Proyaeva, M V; Morozova, T V; Caccavale, F; Segato, F; Sada, C; Kostritskii, S M

2001-05-01

217

Pure E2 transitions: A test for BRICC Internal Conversion Coefficients  

SciTech Connect

The most widely used theoretical internal conversion coefficient (ICC) tables are of Hager and Seltzer (HS), Rosel et al. and BRICC (Band et al. tables using BRICC interpolation code). A rigorous comparison of experimental ICCs with various theoretical tabulations is possible only when a large data on experimental ICCs is available at one place. For this reason, a compilation of all the available experimental ICCs, {alpha}{sub T}, {alpha}{sub K}, {alpha}{sub L} of E2 transitions for a number of elements in the range of 24{<=}Z{<=}94 is presented. Listing of experimental data includes 595 datasets corresponding to 505 E2 transitions in 165 nuclei across the nuclear chart. Data with less than 10% experimental uncertainty have been selected for comparison with the theoretical values of Hager and Seltzer, Rosel et al. and BRICC. The relative percentage deviation (%{delta}) have been calculated for each of the above theories and the average (%{delta}) are estimated. The Band et al. tables, using the BRICC interpolation code are seen to give theoretical ICCs closest to experimental values.

Gerl, J. [Gesellschaft fur Schwerionenforschung, GSI, 64291 Darmstadt (Germany); Sai, K. Vijay; Sainath, M.; Gowrishankar, R.; Venkataramaniah, K. [Department of Physics, Sri Sathya Sai University, Prasanthinilayam 515134, AP (India)

2009-01-28

218

The Lyman-alpha/H-alpha ratio in solar flares and quasars  

NASA Technical Reports Server (NTRS)

Constant temperature and density solar flare models are constructed with temperature and hydrogen density values that reflect reasonable nonlinear averages of those parameters in the depth dependent solar flare chromosphere models of Lites and Cook (1979). Acceptable values of the intensity ratios L-alpha/H-alpha and H-beta/H-alpha correspond to temperatures from about 9000 to 13,000 K, and hydrogen densities from 10 to the 11th to 10 to the 15th cu cm. The H-alpha and Ly-alpha source functions are thermalized at depths consistent with those inferred from independent studies, although the observed Ly-alpha/H-alpha ratio does not necessarily imply an electron temperature appropriate to the Planck function ratio. It is also shown that the value of Ly-alpha/H-alpha depends on the temperature, hydrogen density, and the optical depth of the emitting chromospheric layer.

Canfield, R. C.; Puetter, R. C.; Ricchiazzi, P. J.

1981-01-01

219

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

220

The solar Ly-alpha line profile  

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

221

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

NASA Astrophysics Data System (ADS)

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

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

1993-05-01

222

Analysis of Raman scattered Ly-alpha emissions from the atmosphere of Uranus  

NASA Technical Reports Server (NTRS)

A line at 1280 A, due to Raman scattering of solar Lyman alpha (Ly-alpha) in the atmosphere of Uranus, has been detected by the Voyager Ultraviolet Spectrometer. The measured intensity of 40 + or - 20 R implies that 200 R to 500 R of the measured 1500 R Ly-alpha intensity at the subsolar point is due to Rayleigh scattering of the solar line. The presence of Rayleigh and Raman scattering at 1216 A suggests that the Uranian atmosphere is largely devoid of absorbing hydrocarbons above the 0.5 mbar level. The most natural explanation of this depletion is very weak vertical mixing equivalent to an eddy coefficient on the order of 200 sq cm/sec between 0.5 mbar and 100 mbar.

Yelle, R. V.; Doose, L. R.; Tomasko, M. G.; Strobel, D. F.

1987-01-01

223

Targeted alpha therapy for cancer  

NASA Astrophysics Data System (ADS)

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

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

2004-08-01

224

High gas flow alpha detector  

DOEpatents

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

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

1996-05-07

225

Partition Coefficients at High Pressure and Temperature  

NASA Astrophysics Data System (ADS)

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

Righter, K.; Drake, M. J.

2003-12-01

226

Diffusion Coefficient of Electrons in Real Space  

NASA Astrophysics Data System (ADS)

A Monte-Carlo simulation of electron motion is carried out by a new method to obtain the exact values of swarm parameters. The elastic and total collision cross sections assumed here are proportional to various powers of the electron energy, and the mass ratio of an electron to a gas atom is taken as 10-2. Computation shows that the well-known expression for the diffusion doefficient Dv does not always give the exact values of the lateral diffusion coefficient DT. The differences between the values of Dv and DT are significant when the power value of the collision cross-section is large or the mass ratio is large. The disagreement is thought to be caused by the difference in the procedures for obtaining Dv and DT because of the difference in their definitions.

Ikuta, Nobuaki; Itoh, Hidenori; Toyota, Kazushige

1983-01-01

227

Calculation of combined diffusion coefficients in SF6-Cu mixtures  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

228

Hypoxia and HIF-1alpha in osteoarthritis.  

PubMed

We have previously shown that functional inactivation of hypoxia-inducible factor-1alpha (HIF-1alpha) in growth-plate chondrocytes will dramatically inhibit anaerobic energy generation and matrix synthesis. Using immunohistochemistry, we have now analyzed the spatial distribution of HIF-1alpha and its target genes in normal cartilage and in cartilage from knee joints with osteoarthritis. We detected HIF-1alpha and its target genes in both types of cartilage. In cartilage from joints with osteoarthritis, the number of HIF-1alpha-, Glut-1-, and PGK-1-stained chondrocytes increased with the severity of osteoarthritis. Activated matrix synthesis and strongly decreased oxygen levels are hallmarks of osteoarthritic cartilage. Thus, we assume that chondrocytes are depending on the adaptive functions of HIF-1alpha in order to maintain ATP levels and thereby matrix synthesis during the course of osteoarthritis. PMID:15611874

Pfander, David; Cramer, Thorsten; Swoboda, Bernd

2005-02-01

229

Alpha scattering applications in astrophysics  

NASA Astrophysics Data System (ADS)

This work concentrates oil the applications of elastic scattering data for determining the 26Mg(?,?)26Mg and 13C(?,?)13C reactions. These were done using two experimental setups specifically designed for alpha-scattering here at Notre Dame, one using the FN Tandem accelerator and the large 45? Notre Dame FN scattering chamber, and the other with the KN Van De Graaff accelerator and 16? Ortec chamber. The purpose was to gain information on the related reactions 26Mg(?, n)29Si and 13C(?,n) 16O, which are inconclusively known. The first reaction is of interest, in testing Type II Supernovae models against experimental evidence from dust grains found in meteorites, and the second is a likely neutron source for the main branch of the s-process nucleosynthesis in stars. I will describe setup, astrophysical motivation, and the method of extracting relevant level parameters from the elastic scattering reactions using multi-channel R-matrix theory, and show that more information is needed on these reactions by demonstrating that the parameters from past data do not fully explain the experimental results presented here. I intend to show that alpha scattering is a valuable tool to approach astrophysically interesting reactions which are difficult to measure directly.

Detwiler, Rebecca Sue

2001-07-01

230

Alpha-1 antitrypsin augmentation therapy.  

PubMed

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. PMID:23527997

Wewers, Mark D; Crystal, Ronald G

2013-03-01

231

COMPARISON OF TELEPHOTOMETER MEASUREMENTS OF EXTINCTION COEFFICIENTS WITH SCATTERING AND ABSORPTION COEFFICIENTS  

EPA Science Inventory

During the summer of 1979, coefficients for light extinction in the atmosphere were calculated from measurements made with a telephotometer placed 251 m from a black target in Research Triangle Park, North Carolina. The results are well correlated (r = 0.92 to 0.96) with integrat...

232

Hepatotoxicity of alpha-methyldopa in pregnancy.  

PubMed

Alpha-methyldopa is one of the most widely prescribed antihypertensive agents used during pregnancy. Despite its known potential hepatotoxicity, there have been only a few reports describing hepatotoxicity with the use of this drug during pregnancy. We report here a new case of acute hepatitis in a pregnant woman related to the use of alpha-methyldopa, and briefly review the literature on alpha-methyldopa-induced hepatotoxicity in pregnancy. PMID:20831537

Slim, R; Ben Salem, C; Hmouda, H; Bouraoui, K

2010-06-01

233

alpha-Configuration of Fibrous Proteins  

Microsoft Academic Search

IT is now generally accepted that the polypeptide chain configuration in the group of fibrous proteins designated k-m-e-f by Astbury1, which give the characteristic alpha X-ray diagram, is closely related to the alpha-helix described by Pauling, Corey and Branson2. In its simplest form, however, the alpha-helix does not account for the simultaneous appearance of the 5.2 and 1.5 Å. meridional

R. D. B. Fraser; T. P. Macrae

1961-01-01

234

Beta/alpha continuous air monitor  

DOEpatents

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

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

1988-06-27

235

Alpha-spectrin immunoanalog in Acanthamoeba cells  

Microsoft Academic Search

A monospecific, affinity purified antibody was prepared against chicken erythrocyte alpha-spectrin. The antibody cross-reacted with only one high molecular weight polypeptide (235 kDa) from whole Acanthamoeba cells. The localization of alpha-spectrin-related antigen in Acanthamoeba cells was examined using immunofluorescence and postembedding cytochemical techniques. Three patterns of distribution of alpha-spectrin immunoanalog were distinguished: as submembraneous layer, cytoplasmic aggregates and uniform dispersion

K. Kwiatkowska; A. Sobota

1990-01-01

236

PARTIAL-ENERGY WEIGHTED INTERPOLATION OF LINEAR PREDICTION COEFFICIENTS  

E-print Network

PARTIAL-ENERGY WEIGHTED INTERPOLATION OF LINEAR PREDICTION COEFFICIENTS Tamanna Islam and Peter. Interpolation is done by converting the LP coefficients in one of the follow- ing representations: line spectral

Kabal, Peter

237

Limited Dependent Variable Correlated Random Coefficient Panel Data Models  

E-print Network

for the average slopes of a linear CRC model with a general nonparametric correlation between regressors and random coefficients. I construct a sqrt(n) consistent estimator for the average slopes via varying coefficient regression. The identification of binary...

Liang, Zhongwen

2012-10-19

238

The effective magnetoelectric coefficients of polycrystalline multiferroic composites  

E-print Network

The effective magnetoelectric coefficients of polycrystalline multiferroic composites Shashidhar to calculate the macroscopic magne- toelectric (ME) coefficients of polycrystalline multiferroic composites of multiferroic composites previously reported is partly due to the orientation distribution of particles that has

Li, Jiangyu

239

Measurement and quantification of aggregate thermal coefficient of expansion  

E-print Network

(Verbeck & Haas). . . . 9 Table 2. Thermal Coefficients of different aggregates, Mitchell. . 13 Table 3. Thermal Coefficients of neat cement and mortar, Mitchell. . . . 13 Table 4. Coefficients of thermal expansion of some rock types(Vencanin). . . . . . 15...Aicients of neat cement and mortar, (Mitchell). Specimen Neat Cement Mortar Mixes Thermal Coeff. of expansion, microstrain per deg Fahr Range of values 6 9 - 12 4 4 2 - 7. 0 Concretes 2 3 - 5. 8 I'enecnnnr The coefficient of thermal expansion (CTE...

Chande, Gautam U

2012-06-07

240

Modification of the formulas for third-order aberration coefficients.  

PubMed

New parameters for calculation of third-order aberration coefficients (Seidel aberration coefficients) are introduced. The formulas for Seidel aberration coefficients are linear in these new variables. With these new variables it is possible to calculate the shape and the refractive index of the glass of the individual lenses of the optical system, which was not possible before. PMID:12216880

Miks, Antonín

2002-09-01

241

A new airmass independent formulation for the Linke turbidity coefficient.  

E-print Network

A new airmass independent formulation for the Linke turbidity coefficient. Pierre Ineichen CUEPE@asrc.cestm.albany.edu Abstract We propose a new formulation for the Linke turbidity coefficient with the objective of removing turbidity coefficient. Introduction In a cloudless atmosphere, solar radiation is diffused by the permanent

Perez, Richard R.

242

Does the photon-diffusion coefficient depend on absorption?  

E-print Network

Does the photon-diffusion coefficient depend on absorption? T. Durduran and A. G. Yodh Department the controversy over the precise form of the photon diffusion coefficient and suggest that it is largely diffusion coefficient gives better agreement with theory than the traditionally accepted photon diffusion

Boas, David

243

The effective pyroelectric and thermal expansion coefficients of ferroelectric ceramics  

E-print Network

The effective pyroelectric and thermal expansion coefficients of ferroelectric ceramics JiangYu Li a micromechanical analysis on the effective pyroelectric and thermal expansion coefficients of ferro- electric an estimate on the effective pyroelectric and thermal expansion coefficients of fer- roelectric ceramics

Li, Jiangyu

244

STATE OF CALIFORNIA SOLAR HEAT GAIN COEFFICIENT WORKSHEET: RESIDENTIAL  

E-print Network

STATE OF CALIFORNIA SOLAR HEAT GAIN COEFFICIENT WORKSHEET: RESIDENTIAL CEC-WS-3R (Revised 08/09) CALIFORNIA ENERGY COMMISSION Solar Heat Gain Coefficient Worksheet WS-3R Residential (Page 1 of 2) Site may be used on line 3 of the Solar Heat Gain Coefficient (SHGC) Worksheet (WS-3R) to calculate

245

Review of analysis methods for rotating systems with periodic coefficients  

NASA Technical Reports Server (NTRS)

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

Dugundji, J.; Wendell, J. H.

1981-01-01

246

Measurement of friction coefficients with the atomic force microscope  

E-print Network

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

Attard, Phil

247

Mathematical model of an air-filled alpha stirling refrigerator  

NASA Astrophysics Data System (ADS)

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

McFarlane, Patrick; Semperlotti, Fabio; Sen, Mihir

2013-10-01

248

Attenuation of Lyman-alpha emission by dust in damped Lyman-alpha systems  

Microsoft Academic Search

Relations between the Ly-alpha surface brightness, star formation rate, and abundance of dust in damped Ly-alpha absorption systems are derived. For the dust-to-gas ratio in the damped Ly-alpha systems, the typical value inferred from the reddening of background quasars is adopted. The results of several recent searches from Ly-alpha emission are used to set limits on and estimate the star

Stephane Charlot; S. M. Fall

1991-01-01

249

Preparation of 9-alpha,11-xi-tritiated 17-alpha-ethynylestradiol, mestranol, estradiol-alpha-17-beta, and norethindrone.  

PubMed

The preparation of 9alpha, 11xi-tritiated 17alpha-ethinyl estradiol, mestranol, estradiol-17beta, and norethindrone are described. Estrone-3-methyl ether was employed as starting material, and ethinylation with lithium acetylide-ethylene diamine resulted in 95% mestranol. Demethylation of mestranol with boron tribromide at 0 degrees resulted in 92% 17alpha-ethinyl estradiol. Dimethylsulfoxide was the choice of reagent for the condensation reaction which was complete at room temperature in about 4 hours. The usually less than 3% of unreacted 17-oxo product was removed by Girard separation. Demethylation of methyl ether with boran tribromide in methylene chloride resulted in an excellent yield of 17alpha-ethinyl estradiol-9alpha, 11xi-tritium. 3-methoxyestra-1,3,5-trien-17-one-9alpha, 11xi-tritium was reduced with sodium bis(2-methoxyethoxy) aluminum hydride to the 17beta-hydroxy compound and subsequent demethylation resulted in estradiol-9alpha, 11xi-tritium. The general method of Ringold et al was employed for the preparation of 17beta-hydroxy-17alpha-ethinylestr-4-en-3-one. Improvements for small scale radiosynthesis are also presented. PMID:5126820

Rao, P N

1971-08-01

250

Genetic variation of individual alpha frequency (IAF) and alpha power in a large adolescent twin sample  

Microsoft Academic Search

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

Christine M. Smit; Margaret J. Wright; Narelle K. Hansell; Gina M. Geffen; Nicholas G. Martin

2006-01-01

251

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

Microsoft Academic Search

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

Jie Zhang; Qi Gao

2012-01-01

252

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

ERIC Educational Resources Information Center

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

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

2012-01-01

253

Farmers' Attitudes and Skills of Farm Business Management in Jordan  

ERIC Educational Resources Information Center

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

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

2006-01-01

254

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

Microsoft Academic Search

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

Ülkü Eser Ünaldi; Merve Görkem Bilgi

255

The anisotropic scattering coefficient of sea ice  

NASA Astrophysics Data System (ADS)

transfer in sea ice is subject to anisotropic, multiple scattering. The impact of anisotropy on the light field under sea ice was found to be substantial and has been quantified. In this study, a large data set of irradiance and radiance measurements under sea ice has been acquired with a Remotely Operated Vehicle (ROV) in the central Arctic. Measurements are interpreted in the context of numerical radiative transfer calculations, laboratory experiments, and microstructure analysis. The ratio of synchronous measurements of transmitted irradiance to radiance shows a clear deviation from an isotropic under-ice light field. We find that the angular radiance distribution under sea ice is more downward directed than expected for an isotropic light field. This effect can be attributed to the anisotropic scattering coefficient within sea ice. Assuming an isotropic radiance distribution under sea ice leads to significant errors in light-field modeling and the interpretation of radiation measurements. Quantification of the light field geometry is crucial for correct conversion of radiance data acquired by Autonomous Underwater Vehicles (AUVs) and ROVs.

Katlein, Christian; Nicolaus, Marcel; Petrich, Chris

2014-02-01

256

Cross-talk between integrins {alpha}1{beta}1 and {alpha}2{beta}1 in renal epithelial cells  

SciTech Connect

The collagen-binding integrins {alpha}1{beta}1 and {alpha}2{beta}1 have profoundly different functions, yet they are often co-expressed in epithelial cells. When both integrins are expressed in the same cell, it has been suggested that {alpha}1{beta}1 negatively regulates integrin {alpha}2{beta}1-dependent functions. In this study we utilized murine ureteric bud (UB) epithelial cells, which express no functionally detectable levels of endogenous integrins {alpha}1{beta}1 and {alpha}2{beta}1, to determine the mechanism whereby this regulation occurs. We demonstrate that UB cells expressing integrin {alpha}2{beta}1, but not {alpha}1{beta}1 adhere, migrate and proliferate on collagen I as well as form cellular cords in 3D collagen I gels. Substitution of the transmembrane domain of the integrin {alpha}2 subunit with that of {alpha}1 results in decreased cell adhesion, migration and cord formation. In contrast, substitution of the integrin {alpha}2 cytoplasmic tail with that of {alpha}1, decreases cell migration and cord formation, but increases proliferation. When integrin {alpha}1 and {alpha}2 subunits are co-expressed in UB cells, the {alpha}1 subunit negatively regulates integrin {alpha}2{beta}1-dependent cord formation, adhesion and migration and this inhibition requires expression of both {alpha}1 and {alpha}2 tails. Thus, we provide evidence that the transmembrane and cytoplasmic domains of the {alpha}2 integrin subunit, as well as the {alpha}1 integrin subunit, regulate integrin {alpha}2{beta}1 cell function.

Abair, Tristin D. [Department of Medicine, Division of Nephrology, Vanderbilt University, Nashville, TN 37232 (United States); Department of Cancer Biology, Vanderbilt University, Nashville, TN 37232 (United States); Sundaramoorthy, Munirathinam; Chen, Dong [Department of Medicine, Division of Nephrology, Vanderbilt University, Nashville, TN 37232 (United States); Heino, Jyrki [Department of Biochemistry and Food Chemistry, University of Turku, Turku (Finland); Ivaska, Johanna [VTT Technical Research Centre of Finland, Medical Biotechnology, Turku (Finland); Hudson, Billy G. [Department of Medicine, Division of Nephrology, Vanderbilt University, Nashville, TN 37232 (United States); Department of Biochemistry, Vanderbilt University, Nashville, TN 37232 (United States); Sanders, Charles R. [Department of Biochemistry, Vanderbilt University, Nashville, TN 37232 (United States); Pozzi, Ambra [Department of Medicine, Veterans Affairs Hospital, Nashville, TN 37232 (United States); Department of Medicine, Division of Nephrology, Vanderbilt University, Nashville, TN 37232 (United States); Department of Cancer Biology, Vanderbilt University, Nashville, TN 37232 (United States); Zent, Roy [Department of Medicine, Veterans Affairs Hospital, Nashville, TN 37232 (United States); Department of Medicine, Division of Nephrology, Vanderbilt University, Nashville, TN 37232 (United States); Department of Cancer Biology, Vanderbilt University, Nashville, TN 37232 (United States); Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232 (United States)], E-mail: roy.zent@vanderbilt.edu

2008-11-15

257

Longitudinal and transverse dispersion coefficients in braided rivers.  

PubMed

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

Gu, Li; Jiao, Zinan; Hua, Zulin

2014-01-01

258

Elementary Processes Underlying Alpha Channeling in Tokamaks  

SciTech Connect

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

NM.J. Fisch

2012-06-15

259

Occipital Alpha Training in Mentally Retarded Adolescents.  

ERIC Educational Resources Information Center

Retarded Ss receiving occipital alpha feedback significantly decreased their alpha density in reference to the random feedback (control) group. Results are discussed in terms of potential implications for visual attention, training techniques for mentally retarded adolescents, and other biofeedback applications. (Author)

Thorson, Gary; Lipscomb, Thomas

1982-01-01

260

Psychiatric Symptoms in Alpha-Mannosidosis  

ERIC Educational Resources Information Center

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

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

2005-01-01

261

Lyman alpha Radiation in External Galaxies.  

National Technical Information Service (NTIS)

The Ly alpha line of atomic hydrogen is often a luminous component of the radiation emitted by distant galaxies. Except for those galaxies which have a substantial central source of non-stellar ionizing radiation, most of the Ly alpha radiation emitted by...

D. A. Neufeld, C. F. Mckee

1990-01-01

262

Quasiclassical description of bremsstrahlung in alpha decay  

E-print Network

We revisit the theory of bremsstrahlung in $\\alpha$ decay with a special emphasis on the case of $^{210}$Po, with the aim of finding a unified quasiclassical description that incorporates both the radiation during the tunneling through the Coulomb wall and the finite energy $E_\\gamma$ of the radiated photon up to $E_\\gamma\\sim Q_\\alpha/\\sqrt{\\eta}$, where $Q_\\alpha$ is the $\\alpha$-decay $Q$-value and $\\eta$ is the Sommerfeld parameter. The corrections with respect to previous quasiclassical investigations are found to be substantial, and excellent agreement with a full quantum mechanical treatment is achieved. Furthermore, we find that a dipole-quadrupole interference significantly changes the $\\alpha$-$\\gamma$ angular correlation. Thus, the assumption of a dipole pattern in the analysis of experimental data, obtained with the typically restricted restricted solid angles covered by detectors, is not adequate.

Jentschura, U D; Terekhov, I S; Boie, H; Scheit, H; Schwalm, D

2006-01-01

263

Alpha 1 antitrypsin phenotypes and alcoholic pancreatitis.  

PubMed Central

Altered frequencies of alpha 1 antitrypsin phenotypes have been reported in patients with chronic pancreatitis, suggesting a possible genetic basis for individual susceptibility to this disease. Alpha 1 antitrypsin phenotypes, with particular regard to alcoholic pancreatitis, were studied. Patients with alcoholic pancreatitis were compared with alcoholic control subjects with no history of pancreatic disease. Serum alpha 1 antitrypsin concentrations were raised in pancreatitis patients sampled within one month of an acute attack of pancreatitis, but otherwise values were similar to those of control subjects. There were no significant differences in alpha 1 antitrypsin phenotypes between alcoholics with pancreatitis and alcoholic control subjects. This study of alpha 1 antitrypsin phenotypes provides no evidence of an inherited susceptibility to alcoholic pancreatitis. PMID:1885078

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

1991-01-01

264

ORNL ALPHA MIS data base manual  

SciTech Connect

ALPHA is a general-purpose Management Information System (MIS) sponsored and developed by the Finance and Materials Division of the Oak Ridge National Laboratory (ORNL). It allows users to access any System 1022 data base on ORNL's DECsystem-10 computer to obtain information for use in the process of management. As its name implies, ALPHA is the foundation of most of the business information systems sponsored by the Finance and Materials Division. The purpose of this manual is to aid the experienced ALPHA user in setting up a data base and the associated tables and files to use fully the capabilities of the ALPHA System in solving the routine and the more complex MIS problems. This manual is one of a series of reports documenting the ALPHA System. When completed, these manuals will provide complete systems documentation on ORNL's most versatile and useful MIS.

Grubb, J.W.; Lovin, J.K.; Haese, R.L.

1984-01-01

265

The analysis of predictability of alpha-decay half-life formulae and the alpha partial half-lives of some exotic nuclei  

E-print Network

The predictabilities of the three alpha-decay half-life formulae, the Royer GLDM, the Viola-Seaborg and the Sobiczewski-Parkhomenko formulae, have been evaluated by developing a method based on the ansatz of standard experimental benchmarking. The coefficients of each formula were re-derived using the reliable data of the alpha-standards nuclei. The modified formulae that resulted were used to evaluate the accuracies of the formulae towards the prediction of half-lives of a set of nuclides with well-studied alpha- spectroscopic data as well as a set of exotic alpha-emitters. Further, a simple linear optimization of the modified formulae allowed adjustments for the insufficient statistics of the primary data set without changing the modified formulae. While the three modified formulae showed equivalent results for all the medium heavy nuclei except the odd-odd, the modified GLDM showed relatively the best figures of merit for the odd-odd and superheavy nuclides.

N. Dasgupta-Schubert; M. A. Reyes; V. A. Tamez

2009-10-05

266

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

PubMed

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

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

2002-01-21

267

Determination of alpha_s from the QCD static energy: an update  

E-print Network

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

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

2014-07-31

268

Mean activity coefficient of electrolyte solutions.  

PubMed

In this paper, we deal with the mean activity coefficient, gamma, of electrolyte solutions. The case gamma < or = 1 is investigated. As is generally recognized, the most accepted models (specific ion interaction/Pitzer theory) have the disadvantage of the dependence on semiempirical parameters. These are not directly accessible from experimental measurements, but can only be estimated by means of best-fitting numerical techniques from experimental data. In the general context of research devoted to the achievement of some reduction of complexity, we propose a model of electrolyte solution that allows us to calculate gamma without using fitting parameters where the (upper) concentration exists at which the electrolyte solution exhibits gamma = 1 (molality scale). In the remaining cases, we show that a unique parameter is required, that is, the concentration that should ideally give gamma = 1 for the electrolyte. Compared to other models that do not require adjustable parameters, the present one is generally applicable over a wider range of concentrations; moreover, it does not impose any restriction on the ion-size variations. Our model follows a pseudolattice approach, starting from the primitive idea of a disordered lattice of solute ions within a continuous solvent at extremely dilute solutions and coming to a disordered lattice of local arrangements of both solute ions and solvent dipoles at higher concentrations. Compared to other theories based on lattice models, this work stresses the role of statistical deviations from any time-averaged (lattice) configuration. All formulas in this paper are applied for 1:1, 2:2, 1:2, and 2:1 aqueous electrolytes at 25 degrees C. PMID:17388469

Moggia, Elsa; Bianco, Bruno

2007-03-29

269

Distribution Coefficients of Impurities in Metals  

NASA Astrophysics Data System (ADS)

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

Pearce, J. V.

2014-04-01

270

?-cluster asymptotic normalization coefficients for nuclear astrophysics  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

271

Catalytic Mechanism of Human Alpha-galactosidase  

SciTech Connect

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.

Guce, A.; Clark, N; Salgado, E; Ivanen, D; Kulinskaya, A; Brumer, H; Garman, S

2010-01-01

272

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

PubMed

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

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

2004-12-01

273

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

SciTech Connect

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

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

2009-11-01

274

Deficiency of serum "pregnancy-associated" alpha 2-glycoprotein alpha 2-PAG): association with disease.  

PubMed Central

The serum concentrations of "pregnancy-associated" alpha 2-glycoprotein (alpha 2-PAG) were measured in 129 healthy women and 141 healthy men to establish a normal range, using a sensitive enzyme linked immunosorbent assay. In the normal population 2.8% of men and 5.4% of women had low serum alpha 2-PAG concentrations. Low concentrations occur, however, much more commonly in patients, particularly male patients, with certain diseases, including dermatitis herpetiformis (three of 12 or 25%) and urticaria (two of five or 40%). One female patient with absolute deficiency was also identified. In view of the recently confirmed association of alpha 2-PAG with IgA and the fact that alpha 2-PAG seems to have immunosuppressive properties, it seems likely that deficiency of alpha 2-PAG could result in the subject becoming sensitised to various dietary antigens. Interestingly, none of the 24 patients with IgA deficiency showed concomitant deficiency of alpha 2-PAG. PMID:3950041

Horne, C H; Gerrie, L M; Armstrong, S S; Brunt, P W; Mowat, N A; Sinclair, T S

1986-01-01

275

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

NASA Technical Reports Server (NTRS)

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

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

1979-01-01

276

Variation in quadrupole couplings of alpha deuterons in ubiquitin suggests the presence of C(alpha)-H(alpha)...O=C hydrogen bonds.  

PubMed

Nuclear quadrupolar couplings are sensitive probes of hydrogen bonding. Experimental quadrupolar coupling constants of alpha deuterons (D(alpha) QCC) are reported for the residues of human ubiquitin that do not experience large-amplitude internal dynamics on the pico- to nanosecond time scale. Two different methods for D(alpha) QCC estimation are employed: (i) direct estimation of D(alpha) QCC values from R(1) and R(2) (2)H D(alpha) rates using the dynamics parameters (S(C(alpha)-H(alpha))(2)) derived from 1 micros molecular dynamics simulations as well as from (13)C(alpha) relaxation measurements and (ii) indirect measurements via scalar relaxation of the second kind that affects (13)C(alpha) relaxation rates in (13)C(alpha)-D(alpha) spin systems. A relatively large variability of D(alpha) QCC values is produced by both methods. The average value of 170.6 +/- 3 kHz is derived from the combined data set, with D(alpha) QCC values ranging from 159.2 to 177.2 kHz. The set of lowest quadrupolar couplings in all data sets corresponds to the residues that are likely to form weak C(alpha)-H(alpha)...O=C hydrogen bonds as predicted from the analysis of short H(alpha)...O distances in three-dimensional structures of ubiquitin. These D(alpha) nuclei show up to 10 kHz reduction in their QCC values, which is in agreement with earlier solid-state NMR measurements in alpha deuterons of glycine. A statistically significant correlation is observed between the QCC values of alpha-deuterons and the inverse cube of C(alpha)-H(alpha)...O=C distances in ubiquitin. PMID:20476744

Sheppard, Devon; Li, Da-Wei; Godoy-Ruiz, Raquel; Brüschweiler, Rafael; Tugarinov, Vitali

2010-06-01

277

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

MedlinePLUS

... Behring Talecris Biotherapeutics The mission of the Alpha-1 Foundation is to provide the leadership and resources ... information, visit: www.alpha-1foundation.org. The Alpha-1 Association is the leading national patient membership organization ...

278

Applying alpha-channeling to mirror machines  

SciTech Connect

The {alpha}-channeling effect entails the use of radio-frequency waves to expel and cool high-energetic {alpha} particles born in a fusion reactor; the device reactivity can then be increased even further by redirecting the extracted energy to fuel ions. Originally proposed for tokamaks, this technique has also been shown to benefit open-ended fusion devices. Here, the fundamental theory and practical aspects of {alpha} channeling in mirror machines are reviewed, including the influence of magnetic field inhomogeneity and the effect of a finite wave region on the {alpha}-channeling mechanism. For practical implementation of the {alpha}-channeling effect in mirror geometry, suitable contained weakly damped modes are identified. In addition, the parameter space of candidate waves for implementing the {alpha}-channeling effect can be significantly extended through the introduction of a suitable minority ion species that has the catalytic effect of moderating the transfer of power from the {alpha}-channeling wave to the fuel ions.

Zhmoginov, A. I.; Fisch, N. J. [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544 (United States)

2012-05-15

279

Lyman alpha radiation in external galaxies  

NASA Technical Reports Server (NTRS)

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

Neufeld, David A.; Mckee, Christopher F.

1990-01-01

280

Diabetes and Alpha Lipoic Acid  

PubMed Central

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

Golbidi, Saeid; Badran, Mohammad; Laher, Ismail

2011-01-01

281

Calculation and application of combined diffusion coefficients in thermal plasmas  

NASA Astrophysics Data System (ADS)

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

Murphy, Anthony B.

2014-03-01

282

Prevalence of alpha-thalassemias in northern Thailand.  

PubMed

The population of northern Thailand has one of the highest frequencies of alpha-thalassemia in the world. However, the available distributional data are controversial. In addition to deletional types of alpha-thalassemia Hb, type Constant Spring should also be taken into consideration in alpha-thalassemia population studies, because it causes clinical alpha-thalassemia in the homozygous state or when present with both alpha-globin genes deleted in trans. We have examined a sample of 215 healthy subjects from four rural districts of Chiang Mai province. Out of these, 77 exhibited anomalies of the alpha-globin genes (alpha alpha/-alpha 3.7 in 36; -alpha 3.7/-alpha 3.7 in 3; -SEA in 30; alpha alpha/alpha CS alpha in 5; alpha alpha alpha anti 3.7 in 3). Therefore, no fewer than 2% of the children in northern Thailand are expected to be born with HbH disease or thalassemic hydrops fetalis. The considerable public health problem of hemoglobinopaties and the increasing acceptance of family planning necessitates facilities for the pre- and postnatal diagnosis of these disorders at the DNA level. PMID:8707307

Lemmens-Zygulska, M; Eigel, A; Helbig, B; Sanguansermsri, T; Horst, J; Flatz, G

1996-09-01

283

DCFPAK: Dose coefficient data file package for Sandia National Laboratory  

SciTech Connect

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

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

1996-07-31

284

Essence of the coefficient of effective uplift area  

Microsoft Academic Search

Conclusions 1.It is necessary to distinguish the coefficient of effective area of action of the seeping watera2and coefficient of spatial work of the permeable foundationa2,f. The physical significance of these coefficients is different:The coefficienta2(2) is a unique geometric characteristic of the flow region of the rock mass and figures into the formulas for determining the SFs (3)–(5);The coefficienta2,fdetermines the proportion

V. V. Tetel'min; V. A. Ulyashinskii

1989-01-01

285

On the Connection Coefficients of the Chebyshev-Boubaker Polynomials  

PubMed Central

The Chebyshev-Boubaker polynomials are the orthogonal polynomials whose coefficient arrays are defined by ordinary Riordan arrays. Examples include the Chebyshev polynomials of the second kind and the Boubaker polynomials. We study the connection coefficients of this class of orthogonal polynomials, indicating how Riordan array techniques can lead to closed-form expressions for these connection coefficients as well as recurrence relations that define them. PMID:23990760

2013-01-01

286

Estimation of hydrodynamic coefficients for an AUV using nonlinear observers  

Microsoft Academic Search

Hydrodynamic coefficients strongly affect the dynamic performance of an autonomous underwater vehicle. Although these coefficients are generally obtained experimentally such as through the planar-motion-mechanism (PMM) test, the measured values are not completely reliable because of experimental difficulties and errors involved. Another approach by which these coefficients can be obtained is the observer method, in which a model-based estimation algorithm predicts

Joonyoung Kim; Kihun Kim; Hang S. Choi; Woojae Seong; Kyu-Yeul Lee

2002-01-01

287

Tetroon Drag Coefficients from Experimental Free-Flight Data  

Microsoft Academic Search

Drag coefficients were determined for a 152-cm (60-inch) tetrahedral Mylar plastic balloon in free flight as functions of Reynolds numbers ranging from 104 to 3.3×105. Vertical relative air speeds ranged from 9 to 270 cm sec1. Most drag coefficients derived from the 186 tests lay between 0.7 and 0.8. The average drag coefficient was 0.73 for point-first motion and 0.72

Walter H. Hoecker

1973-01-01

288

Microscopic formula for transport coefficients of causal hydrodynamics  

NASA Astrophysics Data System (ADS)

The Green-Kubo-Nakano formula should be modified in relativistic hydrodynamics because of the problem of acausality and the breaking of sum rules. In this Rapid Communication, we propose a formula to calculate the transport coefficients of causal hydrodynamics based on the projection operator method. As concrete examples, we derive the expressions for the diffusion coefficient, the shear viscosity coefficient, and corresponding relaxation times.

Koide, T.

2007-06-01

289

Microscopic formula for transport coefficients of causal hydrodynamics.  

PubMed

The Green-Kubo-Nakano formula should be modified in relativistic hydrodynamics because of the problem of acausality and the breaking of sum rules. In this Rapid Communication, we propose a formula to calculate the transport coefficients of causal hydrodynamics based on the projection operator method. As concrete examples, we derive the expressions for the diffusion coefficient, the shear viscosity coefficient, and corresponding relaxation times. PMID:17677204

Koide, T

2007-06-01

290

Tunable Seebeck Coefficient in Monolayer Graphene Under Periodic Potentials  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

291

Kubo Formulae for Second-Order Hydrodynamic Coefficients  

E-print Network

At second order in gradients, conformal relativistic hydrodynamics depends on the viscosity eta and on five additional "second-order" hydrodynamical coefficients tauPi, kappa, lambda1, lambda2, and lambda3. We derive Kubo relations for these coefficients, relating them to equilibrium, fully retarded 3-point correlation functions of the stress tensor. We show that the coefficient lambda3 can be evaluated directly by Euclidean means and does not in general vanish.

Guy D. Moore; Kiyoumars A. Sohrabi

2010-07-29

292

Far Ultraviolet Absolute Flux of alpha Virginis  

E-print Network

We present the far ultraviolet spectrum of alpha Virginis taken with EURD spectrograph on-board MINISAT-01. The spectral range covered is from ~900 to 1080 A with 5 A spectral resolution. We have fitted Kurucz models to IUE spectra of alpha Vir and compared the extension of the model to our wavelengths with EURD data. This comparison shows that EURD fluxes are consistent with the prediction of the model within 20-30%, depending on the reddening assumed. EURD fluxes are consistent with Voyager observations but are ~60% higher than most previous rocket observations of alpha Vir.

Carmen Morales; Joaquin Trapero; Jose F. Gomez; Alvaro Gimenez; Veronica Orozco; Stuart Bowyer; Jerry Edelstein; Eric Korpela; Michael Lampton; Jeff Cobb

1999-08-31

293

Alpha particle confinement in tandem mirrors  

SciTech Connect

Mechanisms leading to loss of alpha particles from non-axisymmetric tandem mirrors are considered. Stochastic diffusion due to bounce-drift resonances, which can cause rapid radial losses of high-energy alpha particles, can be suppressed by imposing a 20% rise in axisymmetric fields before the quadrupole transition sections. Alpha particles should then be well-confined until thermal energies when they enter the resonant plateau require. A fast code for computation of drift behavior in reactors is described. Sample calculations are presented for resonant particles in a proposed coil set for the Tandem Mirror Next Step.

Devoto, R.S.; Ohnishi, M.; Kerns, J.; Woo, J.T.

1980-10-10

294

GLC756 decreases TNF-alpha via an alpha2 and beta2 adrenoceptor related mechanism.  

PubMed

GLC756, a polyvalent anti-glaucoma drug showed in an endotoxin-induced-uveitis model (EIU) in rats a significant tumor necrosis factor-alpha (TNF-alpha) decrease in serum, indicating an additional anti-inflammatory potential of this compound. The receptors on which GLC756 binds (D1, D2, D4, alpha-1, alpha-2, 5-HT1A, 5-HT2C, 5-HT1D, 5-HT2 A, beta-1, and beta-2) were suggested to play a role. In order to identify a receptor type mediating the TNF-alpha lowering response, GLC756 was combined with various counteracting compounds (CP). For EIU, 8-week-old Lewis rats were intravenously injected at 160 microg lipopolysaccharide (LPS) from Salmonella typhimurium. Before EIU-induction animals received either one of the CP's or GLC756 alone, or GLC756 in combination with one of the CP's. TNF-alpha was determined in serum 2h post EIU-induction. Treatment with CP's alone indicated that agonistic effects on beta-2 adrenoceptors and antagonistic effects on alpha-2, 5-HT1A and 5-HT1D receptors resulted in statistically significant decreased TNF-alpha levels in comparison to the LPS-control group. In combination with GLC756, the counteracting CP's domitor (alpha-2 adrenoceptor agonist) and ICI 118551 (beta-2 adrenoceptor antagonist) inhibited completely the TNF-alpha decreasing effect of GLC756. Counteracting the 5-HT1A receptor with the 5-HT1A agonist 8-OH-DPAT could not prevent the TNF-alpha decreasing effect of GLC756. In conclusion, the antagonistic effect on alpha-2 adrenoceptors and the agonistic effect on beta-2 adrenoceptors were identified as mechanism for the TNF-alpha decreasing effect of GLC756. PMID:16938291

Laengle, Ulrich W; Trendelenburg, Anne U; Markstein, Rudolf; Nogues, Vicente; Provencher-Bollinger, Anne; Roman, Danielle

2006-11-01

295

GAS KINEMATICS IN Ly{alpha} NEBULAE  

SciTech Connect

Exploring the origin of Ly{alpha} nebulae ('blobs') at high redshift requires measurements of their gas kinematics that are impossible with only the resonant, optically thick Ly{alpha} line. To define gas motions relative to the systemic velocity of the blob, the Ly{alpha} line must be compared with an optically thin line like H{alpha} {lambda}6563, which is not much altered by radiative transfer effects and is more concentrated about the galaxies embedded in the nebula's core. We obtain optical and near-IR (NIR) spectra of the two brightest Ly{alpha} blobs (CDFS-LAB01 and CDFS-LAB02) from the Yang et al. sample using the Magellan/Magellan Echellette Spectrograph optical and Very Large Telescope/SINFONI NIR spectrographs. Both the Ly{alpha} and H{alpha} lines confirm that these blobs lie at the survey redshift, z {approx} 2.3. Within each blob, we detect several H{alpha} sources, which roughly correspond to galaxies seen in Hubble Space Telescope rest-frame UV images. The H{alpha} detections show that these galaxies have large internal velocity dispersions ({sigma}{sub v} = 130-190 km s{sup -1}) and that, in the one system (LAB01), where we can reliably extract profiles for two H{alpha} sources, their velocity difference is {Delta}v {approx} 440 km s{sup -1}. The presence of multiple galaxies within the blobs, and those galaxies' large velocity dispersions and large relative motion, is consistent with our previous finding that Ly{alpha} blobs inhabit massive dark matter halos that will evolve into those typical of present-day rich clusters and that the embedded galaxies may eventually become brightest cluster galaxies. To determine whether the gas near the embedded galaxies is predominantly infalling or outflowing, we compare the Ly{alpha} and H{alpha} line centers, finding that Ly{alpha} is not offset ({Delta}v{sub Ly{alpha}} = +0 km s{sup -1}) in LAB01 and redshifted by only +230 km s{sup -1} in LAB02. These offsets are small compared to those of Lyman break galaxies, which average +450 km s{sup -1} and extend to about +700 km s{sup -1}. In LAB02, we detect C II {lambda}1334 and Si II {lambda}1526 absorption lines, whose blueward shifts of {approx}200 km s{sup -1} are consistent with the small outflow implied by the redward shift of Ly{alpha}. We test and rule out the simplest infall models and those outflow models with super/hyperwinds, which require large outflow velocities. Because of the unknown geometry of the gas distribution and the possibility of multiple sources of Ly{alpha} emission embedded in the blobs, a larger sample and more sophisticated models are required to test more complex or a wider range of infall and outflow scenarios.

Yang Yujin; Jahnke, Knud [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, Heidelberg (Germany); Zabludoff, Ann; Eisenstein, Daniel; Dave, Romeel [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Shectman, Stephen A.; Kelson, Daniel D., E-mail: yyang@mpia.de [Observatories of the Carnegie Institution of Washington, Pasadena, CA 91101 (United States)

2011-07-10

296

Linear Thermal Expansion Coefficients of Higher Manganese Silicide Compounds  

NASA Astrophysics Data System (ADS)

The linear thermal expansion coefficients ?L of the higher manganese silicide compounds are calculated using a combined approach involving Density-Functional Theory calculations, an empirical relation and experimental data. Since it has been reported that the linear thermal expansion coefficient and the cohesive energy are inversely proportional to each other, we calculated by DFT methods the cohesive energies of a set of selected disilicide compounds and using the corresponding experimental data for ?L we determined the coefficient of proportionality. From the empirical relation so obtained, the linear thermal expansion coefficients of the HMS in the ‘a’ and ‘c’ directions were calculated.

Allam, Ali; Boulet, Pascal; Record, Marie-Christine

297

Do thermal diffusion and Dufour coefficients satisfy Onsager's reciprocity relation?  

PubMed

It is commonly admitted that in liquids the thermal diffusion and Dufour coefficients DT and DF satisfy Onsager's reciprocity. From their relation to the cross-coefficients of the phenomenological equations, we are led to the conclusion that this is not the case in general. As illustrative and physically relevant examples, we discuss micellar solutions and colloidal suspensions, where DT arises from chemical reactions or viscous effects but is not related to the Dufour coefficient DF. The situation is less clear for binary molecular mixtures; available experimental and simulation data do not settle the question whether DT and DF are reciprocal coefficients. PMID:25341414

Würger, Alois

2014-10-01

298

Diffusion coefficient of three-dimensional Yukawa liquids  

SciTech Connect

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

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

2013-11-15

299

Nuclear diagnostic for fast alpha particles  

DOEpatents

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

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

1983-11-23

300

Alpha high-power chemical laser program  

NASA Astrophysics Data System (ADS)

Alpha is a megawatt-class hydrogen fluoride, continuous wave, space based chemical laser brassboard which demonstrates and validates technology for space-based applications. It consists of a cylindrical gain generator that exhausts radially outward through circumferential nozzles forming an annular lasing media and an annular ring resonator, which extracts the laser energy. Technical innovations first demonstrated on Alpha include: (1) use of extruded aluminum components, (2) diamond turned, annular optics made of molybdenum, (3) uncooled silicon mirrors, (4) light weight optical benches, and (5) active alignment. Alpha first lased in 1989, and has repeatably demonstrated megawatt-class power and excellent beam quality. Using Alpha, TRW has demonstrated the use of low weight uncooled mirrors in very high power lasers to reduce system jitter. They have performed flawlessly and beam jitter levels were significantly reduced.

Ackerman, Richard A.; Callahan, David; Cordi, Anthony J.; Lurie, Henry; Thomson, Matthew

1995-03-01

301

Genetics Home Reference: Alpha-mannosidosis  

MedlinePLUS

... of sugar molecules (oligosaccharides) attached to certain proteins (glycoproteins). In particular, alpha-mannosidase helps break down oligosaccharides ... cataract ; cell ; deficiency ; depression ; disability ; enzyme ; fetus ; gene ; glycoproteins ; ... hepatosplenomegaly ; hydrocephalus ; inherited ; mannose ; molecule ; motor ; ...

302

International Space Station (ISS) Alpha Concept  

NASA Technical Reports Server (NTRS)

Artist's concept of the final configuration of the International Space Station (ISS) Alpha. The ISS is a multidisciplinary laboratory, technology test bed, and observatory that will provide an unprecedented undertaking in scientific, technological, and international experimentation.

1994-01-01

303

Radioimmunotherapy with alpha-particle emitting radionuclides.  

PubMed

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

Zalutsky, M R; Pozzi, O R

2004-12-01

304

Radioimmunotherapy with alpha-emitting nuclides.  

PubMed

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. PMID:9724387

McDevitt, M R; Sgouros, G; Finn, R D; Humm, J L; Jurcic, J G; Larson, S M; Scheinberg, D A

1998-09-01

305

Influence of fast alpha diffusion and thermal alpha buildup on tokamak reactor performance  

SciTech Connect

The effect of fast alpha diffusion and thermal alpha accumulation on the confinement capability of a candidate Engineering Test Reactor (ETR) plasma (Tokamak Ignition/Burn Experimental Reactor (TIBER-II)) in achieving ignition and steady-state driven operation has been assessed using both global and 1-1/2-D transport models. Estimates are made of the threshold for radial diffusion of fast alphas and thermal alpha buildup. It is shown that a relatively low level of radial transport, when combined with large gradients in the fast alpha density, leads to a significant radial flow with a deleterious effect on plasma performance. Similarly, modest levels of thermal alpha concentration significantly influence the ignition and steady-state burn capability. 23 refs., 9 figs., 4 tabs.

Uckan, N.A.; Tolliver, J.S.; Houlberg, W.A.; Attenberger, S.E.

1987-11-01

306

Deconvolution of Alpha Spectra From Hot Particles  

Microsoft Academic Search

A computer code known as AASIFIT is developed to unfold complex alpha spectra. Peak shapes used in the fitting are obtained\\u000a from the simulations. In addition to activities of the nuclides present in the sample, the code can provide source characterization.\\u000a AASIFIT is applied for a nuclear bomb particle collected in Thule, Greenland. It is shown that direct alpha spectrometry

Roy Pöllänen; Tero Karhunen; Teemu Siiskonen; Harri Toivonen; Andreas Pelikan

307

Alpha-emitters for medical therapy workshop  

SciTech Connect

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

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

1996-12-31

308

alpha-Picoline from Rumex obtusifolius L  

Microsoft Academic Search

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

S. Wilkinson

1958-01-01

309

The Lyman alpha emission of starburst galaxies  

Microsoft Academic Search

Nearby starburst galaxies have consistently shown anomalous Ly-alpha\\/H-beta ratios. It has been suggested that dust, associated with resonant scattering, quenches the Ly-alpha line by a large factor. However, the observed amount of dust can barely account for the large depletion factors. It is proposed here that a much more important effect is the age of the burst. Normal (i.e., case

David Valls-Gabaud

1993-01-01

310

Pyrolysis: incineration of simulated combustible alpha wastes  

Microsoft Academic Search

Design, fabrication, and installation of a unit to demonstrate pyrolysis-;\\u000a incineration of simulated alpha wastes are described. The main reactor in the ;\\u000a unit is a cylinder 7 ft long, lined with refractory in the lower 5¹\\/ ;\\u000a ft to give an effective inside diameter of about 11 in. Four experimental runs, ;\\u000a using simulated alpha wastes, were completed. Average

L. K. Mudge; G. F. Schiefelbein; R. G. Sullivan; R. A. Walter

1975-01-01

311

Transport of Radioactive Material by Alpha Recoil  

SciTech Connect

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

Icenhour, A.S.

2005-05-19

312

Structures of G [alpha [superscript i1  

SciTech Connect

Heterotrimeric G proteins are molecular switches that regulate numerous signaling pathways involved in cellular physiology. This characteristic is achieved by the adoption of two principal states: an inactive, GDP bound state and an active, GTP bound state. Under basal conditions, G proteins exist in the inactive, GDP bound state; thus, nucleotide exchange is crucial to the onset of signaling. Despite our understanding of G protein signaling pathways, the mechanism of nucleotide exchange remains elusive. We employed phage display technology to identify nucleotide state-dependent G{alpha} binding peptides. Herein, we report a GDP-selective G{alpha} binding peptide, KB-752, that enhances spontaneous nucleotide exchange of G{alpha}{sub i} subunits. Structural determination of the G{alpha}{sub i1}/peptide complex reveals unique changes in the G{alpha} switch regions predicted to enhance nucleotide exchange by creating a GDP dissociation route. Our results cast light onto a potential mechanism by which G{alpha} subunits adopt a conformation suitable for nucleotide exchange.

Johnston, Christopher A.; Willard, Francis S.; Jezyk, Mark R.; Fredericks, Zoey; Bodor, Erik T.; Jones, Miller B.; Blaesius, Rainer; Watts, Val J.; Harden, T. Kendall; Sondek, John; Ramer, J. Kevin; Siderovski, David P. (Karo Bio); (UNC); (Purdue)

2010-07-19

313

Liquid-scintillation alpha-detection techniques  

SciTech Connect

Accurate, quantitative determinations of alpha-emitting nuclides by conventional plate-counting methods are difficult because of sample self-absorption problems in counting and because of non-reproducible losses in conventional sample separation methods. Liquid scintillation alpha spectrometry offers an attractive with no sample self-absorption or geometry problems and with 100% counting efficiency. Sample preparation may include extraction of the alpha emitter of interest by a specific organic-phase-soluble compound directly into the liquid scintillation counting medium. Detection electronics use energy and pulse-shape discrimination to yield alpha spectra without beta and gamma background interference. Specific procedures have been developed for gross alpha, uranium, plutonium, thorium, and polonium assay. Possibilities for a large number of other applications exist. Accuracy and reproducibility are typically in the 1% range. Backgrounds on the order of 0.01 cpm are readily achievable. The paper will present an overview of liquid scintillation alpha counting techniques and some of the results achieved for specific applications.

McKlveen, J.W.; McDowell, W.J.

1983-01-01

314

The mode of chaperoning of dithiothreitol-denatured alpha-lactalbumin by alpha-crystallin.  

PubMed

Molecular chaperones prevent the aggregation of partially folded or misfolded forms of protein. alpha-crystallin performs such a function in the ocular lens. To gain insight into the mechanism of the anti-aggregation activity of alpha-crystallin, we performed dynamic light scattering (DLS) measurements investigating its interaction with partially denatured alpha-lactalbumin over a 24 hr period. Analyses were conducted as a function of the concentration of alpha-lactalbumin as well as the bovine alpha-crystallin/alpha-lactalbumin ratio. Additional studies of the systems were performed by HPLC and SDS gel electrophoresis. The particle distribution patterns derived from the DLS data indicated that the chaperoned complex (lactalbumin plus crystallin) is a loose fluffy globular entity. After the complex becomes saturated with lactalbumin, it appears to release the partially denatured lactalbumin which may aggregate into high molecular weight moieties. These eventually may precipitate out of solution. On longer standing, 24hr and over, the chaperoned complex as well as the lactalbumin aggregates become more compact. The chaperoned complex (alpha-crystallin plus alpha-lactalbumin) is in dynamic equilibrium both with the monomeric and the aggregated alpha-lactalbumin population. PMID:10425180

Bettelheim, F A; Ansari, R; Cheng, Q F; Zigler, J S

1999-08-01

315

G-rich oligonucleotides inhibit HIF-1alpha and HIF-2alpha and block tumor growth.  

PubMed

Hypoxia-inducible factor-1 (HIF-1) plays crucial roles in tumor promotion by upregulating its target genes, which are involved in energy metabolism, angiogenesis, cell survival, invasion, metastasis, and drug resistance. The HIF-1alpha subunit, which is regulated by O2-dependent hydroxylation, ubiquitination, and degradation, has been identified as an important molecular target for cancer therapy. We have rationally designed G-rich oligodeoxynucleotides (ODNs) as inhibitors of HIF-1alpha for human cancer therapy. The lead compounds, JG243 and JG244, which form an intramolecular parallel G-quartet structure, selectively target HIF-1alpha and decreased levels of both HIF-1alpha and HIF-2alpha (IC50 < 2 micromol/l) and also inhibited the expression of HIF-1-regulated proteins [vascular endothelial growth factor (VEGF), Bcl-2, and Bcl-XL], but did not disrupt the expression of p300, Stat3, or p53. JG-ODNs induced proteasomal degradation of HIF-1alpha and HIF-2alpha that was dependent on the hydroxylase activity of prolyl-4-hydroxylase-2. JG243 and JG244 dramatically suppressed the growth of prostate, breast, and pancreatic tumor xenografts. Western blots from tumor tissues showed that JG-ODNs significantly decreased HIF-1alpha and HIF-2alpha levels and blocked the expression of VEGF. The JG-ODNs are novel anticancer agents that suppress tumor growth by inhibiting HIF-1. PMID:19755960

Guan, Yongli; Reddy, Kavitha Ramasamy; Zhu, Qiqing; Li, Yifei; Lee, KangAe; Weerasinghe, Priya; Prchal, Josef; Semenza, Gregg L; Jing, Naijie

2010-01-01

316

Extracting electron backscattering coefficients from backscattered electron micrographs  

SciTech Connect

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

Zupanic, F., E-mail: franc.zupanic@uni-mb.si

2010-12-15

317

A FORMULA FOR THE ELECTRON CLOUD MAP COEFFICIENT  

Microsoft Academic Search

The bunch-to-bunch evolution of the electron cloud den- sity can be modeled using a cubic map. The map approach has been proved reliable for RHIC (1) and LHC (2). The coefficients that parameterize the map may be obtained by fitting from time consuming numerical simulations. In this communication we derive a simple approximate formula for the linear coefficient in the

T. Demma; S. Petracca

318

GAMMA RAY ABSORPTION COEFFICIENTS FOR ELEMENTS AND MIXTURES  

Microsoft Academic Search

Mass gamma ray total and energy absorption coefficients are tabulated as ; a function of energy from 0.2 to 10 Mev for various elements, mixtures, and ; compounds. The data presented here are based on the latest published results of ; Dr. G. White Grodstein, National Bureau of Standards. Polynomial expressions are ; given for approximation of absorption coefficients for

Capo

1961-01-01

319

PP spherical-wave reflection coefficients for viscoelastic media  

E-print Network

PP spherical-wave reflection coefficients for viscoelastic media Vlastislav Cerven´y 1) , Ivan at a plane interface between two homoge- neous viscoelastic media are studied. Mostly, the plane-wave reflection coefficients have been used in such studies in the past. For viscoelastic media, however

Cerveny, Vlastislav

320

A Simple Geometric Approach to Approximating the Gini Coefficient  

ERIC Educational Resources Information Center

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

Kasper, Hirschel; Golden, John

2008-01-01

321

Biases and Standard Errors of Standardized Regression Coefficients  

ERIC Educational Resources Information Center

The paper obtains consistent standard errors (SE) and biases of order O(1/n) for the sample standardized regression coefficients with both random and given predictors. Analytical results indicate that the formulas for SEs given in popular text books are consistent only when the population value of the regression coefficient is zero. The sample…

Yuan, Ke-Hai; Chan, Wai

2011-01-01

322

Relative Sensitivity Coefficients of Elements in Spark Source Mass Spectrometry.  

National Technical Information Service (NTIS)

The relative sensitivity coefficient of an element in spark source mass spectrometry is defined and the coefficients of several elements in the matrices of Al, Fe, Ti and Cu are determined. The results are as follows (Fe:1): Mg 12.1, Si 2.0, P 3.6, Ti 1.6...

J. Kai, M. Miki

1966-01-01

323

APPENDIX E Partition Coefficients For Chromium(VI)  

E-print Network

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

324

In-situ determination of thermal coefficients for electrical machines  

Microsoft Academic Search

A method for determining the thermal coefficients in electrical machines based upon a new linear lumped parameter model and accurate measurement of temperature and loss densities within the machine is presented. The thermal network is reduced to a system of simultaneous equations. The equivalent thermal coefficients are determined by solving the equations using a singular value decomposition (SVD) method. Results

A. Bousbaine; M. McCormick; W. F. Low

1995-01-01

325

Field measurements of drag coefficients for model large woody debris  

E-print Network

Field measurements of drag coefficients for model large woody debris Bretagne Hygelunda , Michael Science B.V. All rights reserved. Keywords: Large woody debris; Drag coefficients; Flow resistance; Stress; received in revised form 22 September 2001; accepted 18 October 2002 Abstract Woody debris in rivers can

Manga, Michael

326

Coefficient of external friction in the pressing of metal powders  

Microsoft Academic Search

Experimental data on the external friction in the pressing of copper and iron powders have been processed graphicoanalytically, using Deryagin's binomial law, and the mechanical and adhesional components of the coefficients of friction in the pressing of these powders have been determined. A rise in pressing pressure decreases the static coefficient of friction by reducing its adhesional component.

N. A. Chainikov

1979-01-01

327

Resistance coefficient identification of ballistic with random wind  

Microsoft Academic Search

For the aerodynamic parameters identification of projectile and rocket under the influence of random wind, based on the control system sensitivity theory, the formation of the sensitivity and related mathematical models according to realistic systems are formulated. Sensitivity principle of the control system theory is applied to the identification of resistance coefficient. Analyzing missile system parameters, aerodynamic coefficients are identified

Xin Wang; Yuxin Wang; Jun Yao

2011-01-01

328

Estimating the ballistic coefficient of a re-entry vehicle  

Microsoft Academic Search

Theoretical bounds for estimating the ballistic coefficient of a ballistic object during the re-entry phase have been addressed. One essential characteristic of the vehicle trajectory is its deceleration when it reaches dense atmospheric layers. The intensity of the phenomenon is pro- portional to a scalar, called the ballistic coefficient. This leads to an highly nonlinear time-varying dynamic. To understand the

P. Dodin; P. Minvielle; J. P. Le Cadre

2007-01-01

329

A new correlation coefficient for bivariate time-series data  

NASA Astrophysics Data System (ADS)

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

Erdem, Orhan; Ceyhan, Elvan; Varli, Yusuf

2014-11-01

330

Direct Extraction of One-loop Integral Coefficients  

SciTech Connect

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

Forde, Darren

2007-04-16

331

Self-diffusion coefficient study of liquid lithium  

NASA Astrophysics Data System (ADS)

Little liquid lithium experimental self-diffusion coefficient were reported in the literature because of higher risk of radiation measurement method of diffusion coefficient. In the paper, the EAM potential is applied to calculate self-diffusion coefficient of liquid lithium with emphasis on a wide range of temperature, pressure, magnetic field, and gravity acceleration. The results show that the liquid lithium self-diffusion coefficient increases with temperature increasing and decreases with pressure increasing. Calculated self-diffusion coefficient is in good agreement with Murday's experiment results in atmosphere. We get the Arrhenius equation according to the simulation results. The increasing of pressure enlarges the liquid lithium activation energy and lowers the movement of atom in liquid lithium.

Wang, Z. H.; Ni, M. J.

2012-02-01

332

Self-diffusion coefficient study of liquid lithium  

NASA Astrophysics Data System (ADS)

Little liquid lithium experimental self-diffusion coefficient were reported in the literature because of higher risk of radiation measurement method of diffusion coefficient. In the paper, the EAM potential is applied to calculate self-diffusion coefficient of liquid lithium with emphasis on a wide rage of temperature, pressure, magnetic field, and gravity acceleration. The results show that the liquid lithium self-diffusion coefficient increases with temperature increasing and decreases with pressure increasing. Calculated self-diffusion coefficient is in good agreement with Murday's experiment results in atmosphere. We get the Arrhenius equation according to the simulation results. The increasing of pressure enlarges the liquid lithium activation energy and lowers the movement of atom in liquid lithium.

Wang, Z. H.; Ni, M. J.

2011-08-01

333

Destabilization of low mode number Alfven modes in a tokamak by energetic or alpha particles  

SciTech Connect

With the inclusion of finite Larmor radius effects in the shear Alfven eigenmode equation, the continuous Alfven spectrum, which has been extensively discussed in ideal magnetohydrodynamics, is removed. Neutrally stable, discrete radial eigenmodes appear in the absence of sources of free energy and dissipation. Alpha (or energetic) particle toroidal drifts destabilize these modes, provided the particles are faster than the Alfven speed. Although the electron Landu resonance contributes to damping, a stability study of the parametric variation of the energy and the density scale length of the energetic particles shows that modes with low radial mode numbers remain unstable in most cases. Since the alpha particles are concentrated in the center of the plasma, this drift-type instability suggests anomalous helium ash diffusion. Indeed, it is shown that stochasticity of alpha orbits due to the overlapping of radially neighboring Alfven resonances is induced at low amplitudes, e/sub i//sup approx./phi/T/sub i/ greater than or equal to 0.05, implying a diffusion coefficient D/sub r//sup ..cap alpha../ greater than or equal to 4.4 x 10/sup 3/cm/sup 2//s.

Tsang, K. T.; Sigmar, D. J.; Whitson, J. C.

1980-12-01

334

Validity and reliability of the Persian version of the oral health impact profile (OHIP)-14  

PubMed Central

Background: The need for assessment of oral health related quality of life has been increased over the last decades. The aim of this study was to develop a Persian version of the Oral Health Impact Profile (OHIP)-14 and to evaluate its reliability and validity for its use in Persian-speaking communities. Methods: The original version of the OHIP-14 was translated into the Persian language using the back-translation technique. To establish the reliability of the translated instrument, internal consistency and test-retest reliability trials were performed on 20 subjects (at 4-week intervals); Cronbach’s alpha was used. One hundred sixty adults over 50 years of age who attended Health Care Centers in Sari and Babol were recruited to fill out the questionnaires and received a clinical examination by a single dentist. The socio-demographic and oral health information was also collected. Results: The test-retest reliability was excellent (Cronbach’s alpha = 0.095). In the main study, Cronbach’s reliability coefficient for all 14 questions in each dimension was more than 70%. The individuals in need of dental treatment showed significantly higher OHIP scores than the individuals not requiring treatment. The individuals with hopeless teeth, negative self-perceived oral had significantly higher OHIP scores. Conclusion: The Persian version of the OHIP-14 is a comprehensive and accurate instrument with acceptable reliability and validity for measuring oral health–related quality of life. PMID:24551438

Motallebnejad, Mina; Hadian, Hoora; Mehdizadeh, Shervin; Hajiahmadi, Mahmoud

2011-01-01

335

How Can Alpha-1 Antitrypsin Deficiency Be Prevented?  

MedlinePLUS

... page from the NHLBI on Twitter. How Can Alpha-1 Antitrypsin Deficiency Be Prevented? You can't prevent alpha-1 ... lungs. (For more information, go to "How Is Alpha-1 Antitrypsin Deficiency Treated?" ) Rate This Content: Alpha-1 Antitrypsin Deficiency ...

336

Na IX-X & Mg X-XI recombination rate coefficients (Nahar+, 2006)  

NASA Astrophysics Data System (ADS)

Detailed study on the inverse processes of photoionization and electron-ion recombination for NaIX+h{nu}<->NaX+e, NaX+h{nu}<->NaXI+e, MgX+h{nu}<->Mg{nu}+e, and MgXI+h{nu}<->MgXII+e is reported. The unified method for the total electron-ion recombination is used for the self-consistent results of total and level-specific recombination rate coefficients {alpha}R and {alpha}R(i) (subsuming both radiative recombination [RR] and dielectronic recombination [DR]), total recombination cross sections {sigma}RC, and total and partial level-specific photoionzation cross sections {sigma}PI and {sigma}PI(g). The total recombination spectrum of cross sections and recombination rates versus photoelectron energy are presented for experimental applications. The unified method employs close-coupling approximation in the relativistic Breit-Pauli R-matrix (BPRM) method. The coupled channel wave function expansions for Li-like NaIX and MgX consist of 17 core levels with excitations up to 3d orbital and for He-like NaX and MgXI consist of 16 core levels of excitations up to 4f orbital, respectively. The results are presented for all fine-structure levels of the ions up to n<=10, which correspond to 98 levels with 1/2<=J<=17/2 for Li-like NaIX and MgX, 182 and 185 levels with 0<=J<=10 for He-like NaX and MgXI, respectively. The level specific photoionization cross sections {sigma}PI(nSLJ) and recombination rates {alpha}R(T; nSLJ) are obtained for the first time for these ions. The single-valued total {alpha}R(T) is presented over an extended temperature range for astrophysical and laboratory plasma applications. The total unified R(T) for all ions agrees very well with the available published RR and DR rates. Total recombination rates for H-like NaXI and MgXII are also presented for completeness. The results are expected to be accurate within 10%15% from considerations of important atomic effects such as radiation damping, channel couplings, and interference of DR and RR. The comprehensive data sets are applicable for ionization balance and recombination-cascade models for UV and X-ray lines. (4 data files).

Nahar, S. N.

2007-06-01

337

Cancer radioimmunotherapy with alpha-emitting nuclides.  

PubMed

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

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

2005-05-01

338

Determination of partition coefficients from surface acoustic wave vapor sensor responses and correlation with gas-liquid chromatographic partition coefficients  

SciTech Connect

Surface acoustic wave (SAW) devices coated with a thin film of a stationary phase sense chemical vapors in the gas phase by detecting the mass of the vapor that distributes into the stationary phase. This distribution can be described by the partition coefficient. An equation is presented that allows partition coefficients to be calculated from SAW vapor sensor frequency shifts. The experimental responses of fluoropolyol-coated 158-MHz dual delay line SAW vapor sensors are converted to partition coefficients by this method, and these results are compared with partition coefficients determined by gas-liquid chromatography. These two methods rank the vapors in the same order of increasing sorption, but individual partition coefficient values are not always in precise agreement. The influence of temperature and gas-phase vapor concentration on vapor sorption is also examined.

Grate, J.W.; Snow, A.; Ballantine, D.S. Jr.; Wohltjen, H.; Abraham, M.H.; McGill, R.A.; Sasson, P.

1988-05-01

339

Binding properties of alpha-1 adrenergic receptors in rat cerebral cortex: similarity to smooth muscle  

SciTech Connect

The characteristics of alpha-1 adrenergic receptors in rat cerebral cortex were examined using the radioiodinated alpha-1 adrenergic receptor antagonist ((/sup 125/I)BE). (/sup 125/I)BE labeled a single class of high-affinity binding sites in a particulate fraction of rat cerebral cortex with mass action kinetics and a KD of 57 pM. The binding of (/sup 125/I)BE was inhibited by various alpha adrenergic receptor antagonists, partial agonists and full agonists. The potency of these compounds in competing for the (/sup 125/I)BE binding sites suggested that (/sup 125/I)BE was labeling alpha-1 adrenergic receptors in rat cerebral cortex. In the absence of a physiological concentration of NaCl in the assay medium there was a small (20%) decrease in the density of (/sup 125/I)BE binding sites with no effect on the KD value. The absence of NaCl also caused a 4-fold increase in the potency of norepinephrine in competing for (/sup 125/I)BE binding sites. All drugs competed for (/sup 125/I) BE binding sites with Hill coefficients greater than 0.86, except for oxymetazoline which had a Hill coefficient of 0.77. Scatchard analysis of specific (/sup 125/I)BE binding in the presence of various competing drugs showed that the inhibition by both agonists and antagonists was purely competitive, but the inhibition by oxymetazoline was complex. Treatment of the particulate fraction of rat cerebral cortex with 0.2 to 200 nM phenoxybenzamine for 10 min caused a dose-dependent decrease in the density of (/sup 125/I) BE binding sites which could be mostly blocked by the presence of norepinephrine during the phenoxybenzamine exposure.

Minneman, K.P.

1983-12-01

340

Bayesian semiparametric model with spatially-temporally varying coefficients selection  

PubMed Central

In spatio-temporal analysis, the effect of a covariate on the outcome usually varies across areas and time. The spatial configuration of the areas may potentially depend on not only the structured random intercept but also spatially varying coefficients of covariates. In addition, the normality assumption of the distribution of spatially varying coefficients could lead to potential biases of estimations. In this article, we propose a Bayesian semiparametric space-time model where the spatially-temporally varying coefficient is decomposed as fixed, spatially varying and temporally varying coefficients. The spatially varying coefficients of space-time covariates are modeled nonparametrically by using the area-specific Dirichlet process prior with weights transformed via a generalized transformation. Temporally varying coefficients of covariates are modeled through the dynamic model. Uncertainty of inclusion of the spatially-temporally varying coefficients is also taken into account by variable selection procedure through determining the probabilities of different effects for each covariate. The proposed semiparametric approach shows the improvement compared to the Bayesian spatial-temporal models with normality assumption on spatial random effects and the Bayesian model with the Dirichlet process prior on the random intercept. A simulation example is presented to evaluate the performance of the proposed approach with the competing models. An application to low birth weight data in South Carolina is used for an illustration. PMID:23526312

Cai, Bo; Lawson, Andrew B.; Hossain, Md. Monir; Choi, Jungsoon; Kirby, Russell S.; Liu, Jihong

2013-01-01

341

Human alpha-N-acetylgalactosaminidase (alpha-NAGA) deficiency: no association with neuroaxonal dystrophy?  

PubMed

Two new individuals with alpha-NAGA deficiency are presented. The index patient, 3 years old, has congenital cataract, slight motor retardation and secondary demyelinisation. Screening of his sibs revealed an alpha-NAGA deficiency in his 7-year-old healthy brother who had no clinical or neurological symptoms. Both sibs are homozygous for the E325K mutation, the same genotype that was found in the most severe form of alpha-NAGA deficiency presenting as infantile neuroaxonal dystrophy. Thus, at the age of 7 years the same genotype of alpha-NAGA may present as a 'non-disease' (present healthy case) and can be associated with the vegetative state (the first two patients described with alpha-NAGA deficiency). The clinical heterogeneity among the 11 known individuals with alpha-NAGA deficiency is extreme, with a 'non-disease' (two cases) and infantile neuroaxonal dystrophy (two cases) at the opposite sides of the clinical spectrum. The broad spectrum is completed by a very heterogeneous group of patients with various degrees of epilepsy/behavioural difficulties/psychomotor retardation (four patients) and a mild phenotype in adults without overt neurological manifestations who have angiokeratoma and clear vacuolisation in various cell types (three cases). These observations are difficult to reconcile with a straightforward genotype-phenotype correlation and suggest that factors or genes other than alpha-NAGA contribute to the clinical heterogeneity of the 11 patients with alpha-NAGA deficiency. PMID:11313741

Bakker, H D; de Sonnaville, M L; Vreken, P; Abeling, N G; Groener, J E; Keulemans, J L; van Diggelen, O P

2001-02-01

342

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

E-print Network

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

Suhara, Tadahiro

2014-01-01

343

Planck radiation law and Einstein coefficients reexamined in Kaniadakis ? statistics.  

PubMed

Blackbody radiation is reconsidered using the counterpart of the Bose-Einstein distribution in the ? statistics arising from the Kaniadakis entropy. The generalized Planck radiation law is presented and compared to the usual law, to which it reduces in the limiting case ??0. Effective Einstein's coefficients of emission and absorption are defined in terms of the Kaniadakis parameter ?. It is shown that the Kaniadakis statistics keeps unchanged the first Einstein coefficient A while the second coefficient B admits a generalized form within the present theoretical framework. PMID:25019747

Ourabah, Kamel; Tribeche, Mouloud

2014-06-01

344

On the Li Coefficients for the Hecke L-functions  

NASA Astrophysics Data System (ADS)

In this paper, we compute and verify the positivity of the Li coefficients for the Hecke L-functions using an arithmetic formula established in Omar and Mazhouda, J. Number Theory 125(1), 50-58 (2007) and J. Number Theory 130(4), 1098-1108 (2010) and the Serre trace formula. Additional results are presented, including new formulas for the Li coefficients and a formulation of a criterion for the partial Riemann hypothesis. Basing on the numerical computations made below, we conjecture that these coefficients are increasing in n.

Omar, Sami; Ouni, Raouf; Mazhouda, Kamel

2014-06-01

345

Frictional coefficients of structural materials in AC superconducting coils  

NASA Astrophysics Data System (ADS)

Dyneema ® and glass fiber reinforced plastics (DGFRPs) expand when they are cooled down to cryogenic temperature. Therefore, they may have applications as structural materials in superconducting magnets to increase stability against abrupt motion of superconductors in the magnets. To obtain the mechanical properties of DGFRPs, we measured coefficients of friction on surfaces of DGFRPs under various experimental conditions at three temperatures, four different forces, and two types of DGFRPs. In all of the experimental conditions, the measured coefficients of friction were quite low. The range of measured coefficients was 0.07-0.14.

Sekine, N.; Takao, T.; Shoji, T.; Toyama, H.; Kashiwazaki, K.; Sugasawa, N.; Nakamura, K.; Kashima, T.; Yamanaka, A.; Takeo, M.; Sato, S.

2001-05-01

346

Combined diffusion coefficients for a mixture of three ionized gases  

NASA Astrophysics Data System (ADS)

The combined diffusion coefficient method has been demonstrated to greatly simplify the treatment of diffusion in the modelling of thermal plasmas in gas mixtures without loss of accuracy. In this paper, an extension of this method to allow treatment of diffusion of a three-gas mixture has been achieved, provided that the gases are homonuclear and do not react with each other, and satisfy local chemical equilibrium. Formulas for the combined diffusion coefficients are presented, and combined diffusion coefficients for different mixtures of helium, argon and carbon at temperatures up to 30?000 K and at atmosphere pressure are calculated as an example.

Zhang, X. N.; Murphy, A. B.; Li, H. P.; Xia, W. D.

2014-12-01

347

Maxwell boundary condition and velocity dependent accommodation coefficient  

SciTech Connect

A modification of Maxwell's boundary condition for the Boltzmann equation is developed that allows to incorporate velocity dependent accommodation coefficients into the microscopic description. As a first example, it is suggested to consider the wall-particle interaction as a thermally activated process with three parameters. A simplified averaging procedure leads to jump and slip boundary conditions for hydrodynamics. Coefficients for velocity slip, temperature jump, and thermal transpiration flow are identified and compared with those resulting from the original Maxwell model and the Cercignani-Lampis model. An extension of the model leads to temperature dependent slip and jump coefficients.

Struchtrup, Henning, E-mail: struchtr@uvic.ca [Department of Mechanical Engineering, University of Victoria, Victoria, British Columbia V8W 2Y2 (Canada)] [Department of Mechanical Engineering, University of Victoria, Victoria, British Columbia V8W 2Y2 (Canada)

2013-11-15

348

Alpha-particle sensitive test SRAMs  

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

349

On the Dynamical Foundations of Alpha Disks  

E-print Network

The dynamical foundations of $\\alpha$ disk models are described. At the heart of the viscous formalism of accretion disk models are correlations in the fluctuating components of the disk velocity, magnetic field, and gravitational potential. We relate these correlations to the large scale mean flow dynamics used in phenomenological viscous disk models. MHD turbulence readily lends itself to the $\\alpha$ formalsim, but transport by self-gravity does not. Nonlocal transport is an intrinsic property of turbulent self-gravitating disks, which in general cannot be captured by an $\\alpha$ model. Local energy dissipation and $\\alpha$-like behavior can be re-established if the pattern speeds associated with the amplitudes of an azimuthal Fourier decomposition of the turbulence are everywhere close to the local rotation frequency. In this situation, global wave transport must be absent. Shearing box simulations, which employ boundary conditions forcing local behavior, are probably not an adequate tool for modeling the behavior of self-gravitating disks. As a matter of principle, it is possible that disks which hover near the edge of gravitational stability may behave in accord with a local $\\alpha$ model, but global simulations performed to date suggest matters are not this simple.

S. A. Balbus; J. C. B. Papaloizou

1999-03-02

350

Feasibility of an alpha particle gas densimeter for stack sampling applications  

E-print Network

LISTING APPENDIX C TABULATED RESULTS 58 60 72 VI TA 84 Vi LIST OF TABLES TABLE P age I Typical Flue Gas Compositions II Model Flue Gas Compositions 35 Coeff icients for Alpha particle Stopping Power Functions 59 Computed and Experimental... is obtained using a Type S Pitot. Tube, described in EPA Method 2 , using, 2 V = K 2g AP Ps (4) where, K = pitot tube flow coefficient g = gravitational constant AP = pressure drop data from pitot tube p = stack gas density. s Stack gas density...

Johnson, Randall Mark

2012-06-07

351

Benchmarking the External Surrogate Ratio Method using the (alpha,alpha' f) reaction at STARS  

SciTech Connect

We measured the ratio of the fission probabilities of {sup 234}U* relative to {sup 236}U* formed via an ({alpha},{alpha}{prime}) direct reactions using the STARS array at the 88-inch cyclotron at the Lawrence Berkeley National Laboratory. This ratio has a shape similar to the ratio of neutron capture probabilities from {sup 233}U(n; f) and {sup 235}U(n; f), indicating the alpha reactions likely formed a compound nucleus. This result indicates that the ratios of fission exit channel probabilities for two actinide nuclei populated via ({alpha}, {alpha}{prime}) can be used to determine an unknown fission cross section relative to a known one. The validity of the External Surrogate Ratio Method (ESRM) is tested and the results support the conclusions of Burke et al. [1].

Lesher, S R; Bernstein, L A; Ai, H; Beausang, C W; Bleuel, D; Burke, J T; Clark, R M; Fallon, P; Gibelin, J; Lee, I Y; Lyles, B F; Macchiavelli, A O; McMahan, M A; Moody, K J; Norman, E B; Phair, L; Rodriguez-Vieitez, E; Wiedeking, M

2008-01-09

352

Thermodynamics of concentrated electrolyte mixtures. 9. Activity coefficients in aqueous NaBr-CaBr/sub 2/ mixtures at 25 /sup 0/C  

SciTech Connect

The activity coefficients of NaBr and CaBr/sub 2/ in NaBr-CaBr/sub 2/ aqueous mixtures have been measured at 25/sup 0/C over the ranges of ionic strengths 0.1 to 7.5 m. The measurements were made with a dual electrometer amplifier using Na and Ca ion selective electrodes against a Br ion selective electrode. The data were fitted to Harned's equation of the form log ..gamma../sub i/ = log ..gamma../sub i//sup 0/ - ..cap alpha../sub AB/y/sub B/ - ..beta../sub AB/y/sub B//sup 2/ to compute the trace activity coefficients and were also analyzed by using the Pitzer formation. Deviations from the Pitzer formalism were observed for the experimental activity coefficients in this mixture.

Usha, A.V.; Raju, K.; Atkinson, G.

1987-08-27

353

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

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

354

Nuclear diagnostic for fast alpha particles  

DOEpatents

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

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

1986-01-01

355

Pegylated Interferon Alpha-Associated Optic Neuropathy  

PubMed Central

A 52-year-old man with chronic hepatitis C presented with painless, bilateral, simultaneous non-arteritic anterior ischemic optic neuropathy (NAION) and peripheral neuropathy. Symptoms began 19 weeks after starting peginterferon alpha-2a. The peripheral neuropathy and vision of the right eye improved, but the vision of the left eye worsened after stopping interferon. We identified 23 additional cases of NAION during interferon alpha therapy. At least 12 of these patients suffered bilateral NAION. Patients lost vision 1–40 weeks after initiating therapy. Of 21 eyes that had documented initial and follow-up acuities, 8 improved, 1 worsened, and the rest remained stable. One patient had a painful peripheral neuropathy. Treatment with interferon alpha may result in NAION. Discontinuation of therapy deserves consideration after weighing individual risks and benefits. PMID:20351572

Berg, Kathleen T.; Nelson, Bruce; Harrison, Andrew R.; McLoon, Linda K.; Lee, Michael S.

2013-01-01

356

Chromospheric Lyman Alpha SpectroPolarimeter: CLASP  

NASA Astrophysics Data System (ADS)

The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a VUV spectropolarimeter optimized for measuring the linear polarization of the Lyman-alpha line (121.6 nm). The Lyman-alpha line is predicted to show linear polarization caused by atomic scattering in the chromosphere and modified by the magnetic field through the Hanle effect. The Hanle effect is sensitive to weaker magnetic fields than Zeeman effect, and is not canceled by opposing fields, making it sensitive to tangled or unresolved magnetic field structures. These factors make the Hanle effect a valuable tool for probing the magnetic field in the chromosphere above the quiet sun. To meet this goal, CLASP is designed to measure linear polarization with 0.1% polarization sensitivity at 0.01 nm spectral resolution and 10" spatial resolution. CLASP is scheduled to be launched in 2015.

Kobayashi, Ken; Kano, R.; Trujillo Bueno, J.; Winebarger, A. R.; Cirtain, J. W.; Bando, T.; De Pontieu, B.; Ishikawa, R.; Katsukawa, Y.; Kubo, M.; Narukage, N.; Sakao, T.; Tsuneta, S.; Auchère, F.; Asensio Ramos, A.; Belluzzi, L.; Carlsson, M.; Casini, R.; Hara, H.; Ichimoto, K.; Manso Sainz, R.; Shimizu, T.; Stepan, J.; Suematsu, Y.; Holloway, T.

2013-07-01

357

The Lyman alpha emission of starburst galaxies  

NASA Technical Reports Server (NTRS)

Nearby starburst galaxies have consistently shown anomalous Ly-alpha/H-beta ratios. It has been suggested that dust, associated with resonant scattering, quenches the Ly-alpha line by a large factor. However, the observed amount of dust can barely account for the large depletion factors. It is proposed here that a much more important effect is the age of the burst. Normal (i.e., case B recombination) ratios are observed if the galaxy is currently undergoing the burst, while anomalous ratios appear when the galaxy is observed in the post-burst phase. Underlying stellar populations in the UV spectra should therefore be older in the latter case. This scenario explains the presence of Ly-alpha in absorption. Implications for deep surveys are also discussed.

Valls-Gabaud, David

1993-01-01

358

AlphaCor artificial cornea: clinical outcome  

PubMed Central

Purpose The purpose of this study was to describe the long-term results of AlphaCor implantations, and to evaluate the main complications and risk factors. Methods Retrospective analysis of preoperative and follow-up data from 15 AlphaCor implantations. Analysis of outcomes, trends, and associations was performed and compared with data from published clinical trials and a literature review. Results The survival rate of the device at 1, 2, and 3 years was 87%, 58%, and 42%, respectively. Postoperative visual acuity ranged from hand movement to 0.8. The most significant complications were stromal melt (nine cases), optic deposition (three eyes), and retroprosthetic membrane formation (three eyes). The most common device-unrelated complication was trauma (three patients). All complications were managed without loss of the eye. Conclusion AlphaCor provides a treatment option for patients with corneal blindness in which a donor tissue graft would not succeed. PMID:21681219

Jiraskova, N; Rozsival, P; Burova, M; Kalfertova, M

2011-01-01

359

Asymptotic normalization coefficients, spectroscopic factors, and direct radiative capture rates  

E-print Network

We compare the use of asymptotic normalization coefficients (ANC's) and spectroscopic factors determined from peripheral transfer reactions for determining the overall normalization of peripheral direct radiative capture reaction processes. We...

Mukhamedzhanov, AM; Gagliardi, Carl A.; Tribble, Robert E.

2001-01-01

360

Extended capillary wave theory and the ellipsometric coefficient  

NASA Astrophysics Data System (ADS)

The extended capillary wave theory (ECW) proposed by Robledo et al. and formulated in terms of the unknown direct correlation function C of the two-phase system with a planar interface between liquid and its vapor, is applied to our simulation data on the full inhomogeneous two-point correlation function H from which C is also obtained. The required projection, C¯(q), is shown and discussed. The coefficient of q4, the apparent bending coefficient, was inequivocally negative, in agreement with the view that the true bending coefficient may be absent in one-component interfaces. The ellipsometric coefficient diverged and its calculation still required an ultraviolet cutoff. It is thus demonstrated that ECW is but the first step and further terms, some discovered earlier, as well as mode-mode coupling, are required. These are discussed.

Stecki, J.

1998-09-01

361

A simple estimator for the distribution of random coefficients  

E-print Network

We propose a simple mixtures estimator for recovering the joint distribution of parameter heterogeneity in economic models, such as the random coefficients logit. The estimator is based on linear regression subject to ...

Ryan, Stephen

362

Defining the coupling coefficient for electrodynamic transducers Shuo Chenga)  

E-print Network

convert energy between the electrical and mechanical energy domains using interactions of magnetic fields Interdisciplinary Microsystems Group, Department of Electrical and Computer Engineering, University of Florida, 213 September 2013) This paper provides a simple, practical definition of the coupling coefficient

Allen, Jont

363

Depolarization coefficients of light in multiply scattering media  

NASA Astrophysics Data System (ADS)

The depolarization coefficients are calculated for multiply scattered linearly and circularly polarized light. For a number of media (aqueous suspension of polystyrene particles, water droplets in air), the calculations are carried out both numerically, with solving the vector radiative transfer equation and analytically, within the polarization mode approximation. In the latter case the depolarization coefficients are expressed explicitly in terms of the scattering and absorption coefficients, and the scattering matrix elements of the medium. The range of applicability of the polarization mode approximation is established. For most practically important cases, this method is shown to provide a satisfactory degree of accuracy. We also find the fundamental values of the depolarization coefficients for a Rayleigh medium.

Gorodnichev, E. E.; Kuzovlev, A. I.; Rogozkin, D. B.

2014-10-01

364

Temperature and Strain Coefficient of Velocity for Langasite SAW Devices.  

National Technical Information Service (NTIS)

Surface Acoustic Wave sensors on Langasite substrates are being investigated for aerospace applications. Characterization of the Langasite material properties must be performed before sensors can be installed in research vehicles. The coefficients of velo...

G. M. Atkinson, W. C. Wilson

2013-01-01

365

On the friction coefficient of straight-chain aggregates  

E-print Network

A methodology to calculate the friction coefficient of an aggregate in the continuum regime is proposed. The friction coefficient and the monomer shielding factors, aggregate-average or individual, are related to the molecule-aggregate collision rate that is obtained from the molecular diffusion equation with an absorbing boundary condition on the aggregate surface. Calculated friction coefficients of straight chains are in very good agreement with previous results, suggesting that the friction coefficients may be accurately calculated from the product of the collision rate and an average momentum transfer,the latter being independent of aggregate morphology. Langevin-dynamics simulations show that the diffusive motion of straight-chain aggregates may be described either by a monomer-dependent or an aggregate-average random force, if the shielding factors are appropriately chosen.

Lorenzo Isella; Yannis Drossinos

2010-07-16

366

APPORTIONING LIGHT EXTINCTION COEFFICIENTS TO CHEMICAL SPECIES IN ATMOSPHERIC AEROSOL  

EPA Science Inventory

A 1978 Denver aerosol data set has been analyzed by a variety of methods for determining light scattering and extinction coefficients per unit mass concentration for specific chemical species in fine particles (...

367

Hanford Contaminant Distribution Coefficient Database and Users Guide.  

National Technical Information Service (NTIS)

The purpose of this work is to compile and thoroughly document all useful distribution coefficient data determined for Hanford sediment and related materials into one database. This report provides the background information to access the database and pro...

K. J. Cantrell, R. J. Serne, G. V. Last

2002-01-01

368

Transfer having a coupling coefficient higher than its active material  

NASA Technical Reports Server (NTRS)

A coupling coefficient is a measure of the effectiveness with which a shape-changing material (or a device employing such a material) converts the energy in an imposed signal to useful mechanical energy. Device coupling coefficients are properties of the device and, although related to the material coupling coefficients, are generally different from them. This invention describes a class of devices wherein the apparent coupling coefficient can, in principle, approach 1.0, corresponding to perfect electromechanical energy conversion. The key feature of this class of devices is the use of destabilizing mechanical pre-loads to counter inherent stiffness. The approach is illustrated for piezoelectric and thermoelectrically actuated devices. The invention provides a way to simultaneously increase both displacement and force, distinguishing it from alternatives such as motion amplification, and allows transducer designers to achieve substantial performance gains for actuator and sensor devices.

Lesieutre, George A. (Inventor); Davis, Christopher L. (Inventor)

2001-01-01

369

Scale And Frequency Dependence Of Reflection And Transmission Coefficients  

E-print Network

Well-logs show that heterogeneities occur at many different spatial scales. In this paper, we want to characterize how waves are affected by these heterogeneities, and we study how reflection and transmission coefficients ...

Imhof, Matthias G.

1998-01-01

370

COS FUV01 Detector Calibration Coefficients Date: August 8, 2002  

E-print Network

Table of Contents 1. Overview of FUV Detector Telemetry Calibrations....................................................1 2. FUV01 Telemetry Calibration Coefficients TELEMETRY CALIBRATIONS Telemetry values for the COS FUV Detector subsystem are converted from digital values

Colorado at Boulder, University of

371

The solubility and diffusion coefficient of helium in uranium dioxide  

NASA Astrophysics Data System (ADS)

The solubility and diffusion coefficient of helium in the single-crystal UO 2 samples were determined by a Knudsen-effusion mass-spectrometric method. The measured helium solubilities were found to lie within the scatter of the available data, but to be much lower than those for the polycrystalline samples. The diffusion analysis was conducted based on a hypothetical equivalent sphere model and the simple Fick's law. The helium diffusion coefficient was determined by using the pre-exponential factor and activation energy as the fitting parameters for the measured and calculated fractional releases of helium. The optimized diffusion coefficients were in good agreement with those obtained by a nuclear reaction method reported in the past. It was also found that the pre-exponential factors of the determined diffusion coefficients were much lower than those analyzed in terms of a simple interstitial diffusion mechanism.

Nakajima, Kunihisa; Serizawa, Hiroyuki; Shirasu, Noriko; Haga, Yoshinori; Arai, Yasuo

2011-12-01

372

Characterization of carbon fibers: coefficient of thermal expansion and microstructure  

E-print Network

and develop optimal processing procedures as well as computational simulations to predict properties and allowables for fiber-reinforced composites. The mismatch between the coefficient of thermal expansion of the fiber and the matrix has a profound impact...

Kulkarni, Raghav Shrikant

2006-04-12

373

Transport Coefficients for Holographic Hydrodynamics at Finite Energy Scale  

E-print Network

We investigate the relations between black hole thermodynamics and holographic transport coefficients in this paper. The formulae for DC conductivity and diffusion coefficient are verified for electrically single-charged black holes. We examine the correctness of the proposed expressions by taking charged dilatonic and single-charged STU black holes as two concrete examples, and compute the flows of conductivity and diffusion coefficient by solving the linear order perturbation equations. We then check the consistence by evaluating the Brown-York tensor at a finite radial position. Finally, we find that the retarded Green functions for the shear modes can be expressed easily in terms of black hole thermodynamic quantities and transport coefficients.

Xian-Hui Ge; Hong-Qiang Leng; Li Qing Fang; Guo-Hong Yang

2014-08-19

374

Transport Coefficients for Holographic Hydrodynamics at Finite Energy Scale  

E-print Network

We investigate the relations between black hole thermodynamics and holographic transport coefficients in this paper. The formulae for DC conductivity and diffusion coefficient are verified for electrically single-charged black holes. We examine the correctness of the proposed expressions by taking charged dilatonic and single-charged STU black holes as two concrete examples, and compute the flows of conductivity and diffusion coefficient by solving the linear order perturbation equations. We then check the consistence by evaluating the Brown-York tensor at a finite radial position. Finally, we find that the retarded Green functions for the shear modes can be expressed easily in terms of black hole thermodynamic quantities and transport coefficients.

Ge, Xian-Hui; Fang, Li Qing; Yang, Guo-Hong

2014-01-01

375

A Method for Approximating the Bivariate Normal Correlation Coefficient.  

ERIC Educational Resources Information Center

Improvements of the Gaussian quadrature in conjunction with the Newton-Raphson iteration technique (TM 000 789) are discussed as effective methods of calculating the bivariate normal correlation coefficient. (CK)

Kirk, David B.

376

NON-NEGATIVE CD-COEFFICIENTS OF GORENSTEIN* NATHAN READING  

E-print Network

NON-NEGATIVE CD-COEFFICIENTS OF GORENSTEIN* POSETS NATHAN READING Abstract. We give a convolution-index, Charney-Davis Conjecture, Eulerian poset, flag f-vector, Gorenstein. 1 #12;2 NATHAN READING Theorem 2

Reading, Nathan

377

Determination of optical absorption coefficient with focusing photoacoustic imaging.  

PubMed

Absorption coefficient of biological tissue is an important factor for photothermal therapy and photoacoustic imaging. However, its determination remains a challenge. In this paper, we propose a method using focusing photoacoustic imaging technique to quantify the target optical absorption coefficient. It utilizes the ratio of the amplitude of the peak signal from the top boundary of the target to that from the bottom boundary based on wavelet transform. This method is self-calibrating. Factors, such as absolute optical fluence, ultrasound parameters, and Gru?neisen parameter, can be canceled by dividing the amplitudes of the two peaks. To demonstrate this method, we quantified the optical absorption coefficient of a target with various concentrations of an absorbing dye. This method is particularly useful to provide accurate absorption coefficient for predicting the outcomes of photothermal interaction for cancer treatment with absorption enhancement. PMID:22734746

Li, Zhifang; Li, Hui; Zeng, Zhiping; Xie, Wenming; Chen, Wei R

2012-06-01

378

Correlation equation for the marine drag coefficient and wave steepness  

NASA Astrophysics Data System (ADS)

This work questions, starting from dimensional considerations, the generality of the belief that the marine drag coefficient levels off with increasing wind speed. Dimensional analysis shows that the drag coefficient scales with the wave steepness as opposed to a wave-age scaling. A correlation equation is employed here that uses wave steepness scaling at low aspect ratios (inverse wave steepnesses) and a constant drag coefficient at high aspect ratios. Invoked in support of the correlation are measurements sourced from the literature and at the FINO1 platform in the North Sea. The correlation equation is then applied to measurements recorded from buoys during the passage of hurricanes Rita, Katrina (2005) and Ike (2008). Results show that the correlation equation anticipates the expected levelling off in deeper water, but a drag coefficient more consistent with a Charnock type relation is also possible in more shallower water. Some suggestions are made for proceeding with a higher-order analysis than that conducted here.

Foreman, Richard J.; Emeis, Stefan

2012-09-01

379

Abundance coefficients, a new method for measuring microorganism relative abundance  

USGS Publications Warehouse

A new method of measuring the relative abundance of microorganisms by using a set of interrelated coefficients, termed 'abundance coefficients' or 'AC', is proposed. These coefficients provide a means of recording abundance for geometric density categories, and each density measurement represents an approximation of the Poisson parameter ??t. The AC is the natural logarithm of a 'characteristic value,' which is a particular number for each geometric density category. The 'characteristic values' are based upon a probabilistic error statement derived from the Poisson formula, and they present evidence for separation of the geometric category boundaries by e = 2.71828. The proposed AC provide a means for recording species abundance in a manner suitable for arithmetic manipulation, for population structure studies, and for the determination of practical limits for defining the presence or absence of a species. Further, these coefficients provide for both intrasample and intersample abundance comparisons. ?? 1977 Plenum Publishing Corporation.

Forester, R.M.

1977-01-01

380

Human eosinophils can express the cytokines tumor necrosis factor-alpha and macrophage inflammatory protein-1 alpha.  

PubMed Central

By in situ hybridization, 44-100% of the blood eosinophils from five patients with hypereosinophilia and four normal subjects exhibited intense hybridization signals for TNF-alpha mRNA. TNF-alpha protein was detectable by immunohistochemistry in blood eosinophils of hypereosinophilic subjects, and purified blood eosinophils from three atopic donors exhibited cycloheximide-inhibitable spontaneous release of TNF-alpha in vitro. Many blood eosinophils (39-91%) from hypereosinophilic donors exhibited intense labeling for macrophage inflammatory protein-1 alpha (MIP-1 alpha) mRNA, whereas eosinophils of normal donors demonstrated only weak or undetectable hybridization signals for MIP-1 alpha mRNA. Most tissue eosinophils infiltrating nasal polyps were strongly positive for both TNF-alpha and MIP-1 alpha mRNA. By Northern blot analysis, highly enriched blood eosinophils from a patient with the idiopathic hypereosinophilic syndrome exhibited differential expression of TNF-alpha and MIP-1 alpha mRNA. These findings indicate that human eosinophils represent a potential source of TNF-alpha and MIP-1 alpha, that levels of expression of mRNA for both cytokines are high in the blood eosinophils of hypereosinophilic donors and in eosinophils infiltrating nasal polyps, that the eosinophils of normal subjects express higher levels of TNF-alpha than MIP-1 alpha mRNA, and that eosinophils purified from the blood of atopic donors can release TNF-alpha in vitro. Images PMID:8514874

Costa, J J; Matossian, K; Resnick, M B; Beil, W J; Wong, D T; Gordon, J R; Dvorak, A M; Weller, P F; Galli, S J

1993-01-01

381

Deep H alpha images of interacting galaxies  

NASA Technical Reports Server (NTRS)

Gravitational interactions between galaxies are believed to increase star formation activity dramatically, and most of the brightest starburst galaxies show clear signs of recent interactions. However, it is still not known how interaction triggers star formation, nor are there models to relate the type or strength of interaction to the location or amount of star formation. We report on a series of deep H alpha images of interacting and post-interaction galaxies which we took with the purpose of finding the young stars and ionized gas in these objects. We were motivated in part by the hope that by studying the very recently formed stars we could see how the interaction process had affected the star formation. We observed the galaxies through 50 A-wide filters, one on the redshifted H alpha line and one off, and a standard R filter. Depending on the galaxy and conditions, images in the B, V, and I filters were also obtained. The images were recorded with a 4x7 ft. or 17 ft. diameter CCD at the 1-meter telescope of the Wise Observatory in Mitzpe Ramon. The H alpha and continuum images are used, together with observations at other wavelengths, to put together as complete a picture as possible of star formation and interactions in each galaxy. The complete observation set is not yet available for all the galaxies but certain results are already clear. There do not seem to be any correlations between H 1 and H alpha structures. In some H 1 plume galaxies H alpha extensions were seen on the other side of the galaxy from the H 1; in others extensive H alpha filaments have been found but not H 1. The preliminary results agree with the simplest model that interaction-induced star formation will be concentrated in the system center, since that is where the mass ends up.

Beck, S. C.; Kovo, O.

1993-01-01

382

Determination of the scattering coefficient, the reduced scattering coefficient, and the anisotropy factor of tissue with differential interference contrast microscopy  

NASA Astrophysics Data System (ADS)

We report an approach for determination of the scattering coefficient, the reduced scattering coefficient, and the anisotropy factor from the quantitative phase map measured by differential interference contrast microscopy based on the scatteringphase theorem. The approach is first validated by showing the excellent agreement between the retrieved optical properties of polystyrene spheres and Intralipid-20% suspension and their known values. The scattering properties of unstained pathological prostate cancer slides and fresh cancerous and normal colon tissue samples are then investigated. A clear trend with cancer in the reduced scattering coefficient and the anisotropy factor is shown. The potential of the approach for tissue diagnosis is discussed at the end.

DeAngelo, Bianca; Arzumanov, Grant; Shanley, Patrick; Xu, Zhang; Xu, M.

2012-03-01

383

Third-order aberration coefficients of a thick lens.  

PubMed

In this paper, formulas are described for the calculation of the third-order aberration (Seidel) coefficients for a thick lens in air. The explicit analytic dependence of individual aberration coefficients on a lens thickness is presented. Such formulas make it possible to analyze an influence of the lens thickness on lens aberration properties and the replacement of a thick lens optical system by a thin lens model. PMID:23207297

Mikš, Antonin; Novák, Ji?í

2012-11-20

384

Measurement unit invariant coefficients in multiplicative-logarithmic functions  

Microsoft Academic Search

It has been demonstrated that the coefficients of the non-multiplicative terms of a multiplicative-logarithmic function are dependent on the units used. In addition, Dickey-Fuller tests on the multiplicative terms are unit sensitive. It is demonstrated that a simple transformation circumvents these problems. It is still true that individual coefficients of logarithmic variables in such functions are meaningless and that the

David I. Stern

1995-01-01

385

The third virial coefficient for nonpolar gases and their mixtures  

NASA Astrophysics Data System (ADS)

For a model quasi-spherical pair potential and for the modified nonadditive three-particle potential of Midzuno and Kihara (1956), the additive and nonadditive components of the third virial coefficient have been determined using numerical methods. The computations have been carried out for the normalized temperature range 0.45-12 and the nonsphericity parameter range 0-0.4. Expressions are presented for calculating the 'mixed' third virial coefficients.

Zykov, N. A.; Sevastianov, R. M.; Cherniavskaia, R. A.

1983-03-01

386

Continuously Tunable Microwave Photonic Notch Filter With a Complex Coefficient  

Microsoft Academic Search

This paper presents a continuously tunable microwave photonic notch filter with a complex coefficient. The complex coefficient is generated using a radio-frequency (RF) phase shifter that consists of a dual-parallel Mach-Zehnder modulator (DPMZM) and a tunable optical bandpass filter (TBPF). By simply controlling the bias voltage of the DPMZM, the frequency response of the filter can be continuously tuned over

Wei Li; Ning Hua Zhu; Li Xian Wang

2011-01-01

387

Coefficient quantization effects in block state variable digital filters  

E-print Network

COEFFICIENT QUANTIZATION EFFECTS IN BLOCK STATE VARIABLE DIGITAL FILTERS A Thesis by KAB JOO LEE Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requirements for the degree of MASTER.... Griss old (IMember) , lu M Donald I&. Fricsen (Member) Nasser Ivehtarnavaz' (Member) . J. 'KV. Howze (Head of Department) August I~JcJI 111 ABSTRACT Coefficient Quantization Effects in Block State Variable Digital Filters. (August 1991) Kab...

Lee, Kab Joo

2012-06-07

388

Radius Constants for Analytic Functions with Fixed Second Coefficient  

PubMed Central

Let f(z) = z + ?n=2?anzn be analytic in the unit disk with the second coefficient a2 satisfying |a2 | = 2b, 0 ? b ? 1. Sharp radius of Janowski starlikeness is obtained for functions f whose nth coefficient satisfies |an | ? cn + d??(c, d ? 0) or |an | ? c/n??(c > 0??and??n ? 3). Other radius constants are also obtained for these functions, and connections with earlier results are made. PMID:25101327

Nargesi, Mahnaz M.; Ali, Rosihan M.; Ravichandran, V.

2014-01-01

389

Transport Coefficients of Quark Gluon Plasma for Pure Gauge Models  

NASA Astrophysics Data System (ADS)

The transport coefficients of quark gluon plasma are calculated on a lattice 16 3 × 8, with the pure gauge models. Matsubara Green's functions of energy momentum tensors have very large fluctuations and about a few million MC sweeps are needed to reduce the errors reasonably small in the case of the standard action. They are much suppressed if Iwasaki's improved action is employed. Preliminary results show that the transport coefficients roughly depend on the coupling constant as a-3( g).

Nakamura, A.; Sakai, S.; Amemiya, K.

1997-02-01

390

Damping coefficients for near-fault ground motion response spectra  

Microsoft Academic Search

Damping coefficients are frequently used in earthquake engineering as a simple way to adjust the pseudo-acceleration or displacement response spectra associated with a viscous damping ratio of 5% to the higher values of viscous damping needed for design of structures equipped with base isolation and\\/or supplemental energy dissipation devices. In this study, damping coefficients for the single-degree-of-freedom system subjected to

Derek T. Hubbard; George P. Mavroeidis

2011-01-01

391

Trends in band-gap pressure coefficients in chalcopyrite semiconductors  

Microsoft Academic Search

We present the results of a first-principles calculation of the direct band-gap pressure coefficient ag for a series of Ga and In semiconductor compounds with both the chalcopyrite (e.g., CuGaSe2 and CuInSe2) and the zinc-blende structures (e.g., GaAs and InAs). We found good agreement between the calculated and experimental pressure coefficients. We found that ag in chalcopyrites are dramatically reduced

Su-Huai Wei; Alex Zunger; In-Hwan Choi; Peter Y. Yu

1998-01-01

392

A note on Hansen's coefficients in satellite theory  

NASA Technical Reports Server (NTRS)

General formulas for Hansen's coefficients in satellite theory are derived along with expressions for the eccentricity functions G and H. Recurrence relations for the eccentricity functions and their derivatives are obtained which are valid for all values of the parameter p. It is noted that the recurrence relations obtained by Challe and Laclaverie (1969) as well as by Balmino (1973) do not satisfy certain parity conditions and therefore involve coefficients outside the range of usage.

Giacaglia, G. E. O.

1976-01-01

393

The temperature variation of hydrogen diffusion coefficients in metal alloys  

NASA Technical Reports Server (NTRS)

Hydrogen diffusion coefficients were measured as a function of temperature for a few metal alloys using an electrochemical evolution technique. Results from these measurements are compared to those obtained by the time-lag method. In all cases, diffusion coefficients obtained by the electrochemical method are larger than those by the time-lag method by an order of magnitude or more. These differences are attributed mainly to hydrogen trapping.

Danford, M. D.

1990-01-01

394

Lunar surface outgassing and alpha particle measurements  

SciTech Connect

The Lunar Prospector Alpha Particle Spectrometer (LP APS) searched for lunar surface gas release events and mapped their distribution by detecting alpha particle?; produced by the decay of gaseous radon-222 (5.5 MeV, 3.8 day half-life), solid polonium-2 18 (6.0 MeV, 3 minute half-life), and solid polonium-210 (5.3 MeV, 138 day half-life, but held up in production by the 21 year half-life of lead-210). These three nuclides are radioactive daughters from the decay of uranium-238.

Lawson, S. L. (Stefanie L.); Feldman, W. C. (William C.); Lawrence, David J. (David Jeffery),; Moore, K. R. (Kurt R.); Elphic, R. C. (Richard C.); Maurice, S. (Sylvestre); Belian, Richard D.; Binder, Alan B.

2002-01-01

395

Parallel Genetic Algorithm for Alpha Spectra Fitting  

NASA Astrophysics Data System (ADS)

We present a performance study of alpha-particle spectra fitting using parallel Genetic Algorithm (GA). The method uses a two-step approach. In the first step we run parallel GA to find an initial solution for the second step, in which we use Levenberg-Marquardt (LM) method for a precise final fit. GA is a high resources-demanding method, so we use a Beowulf cluster for parallel simulation. The relationship between simulation time (and parallel efficiency) and processors number is studied using several alpha spectra, with the aim of obtaining a method to estimate the optimal processors number that must be used in a simulation.

García-Orellana, Carlos J.; Rubio-Montero, Pilar; González-Velasco, Horacio

2005-01-01

396

Bremsstrahlung in alpha-Decay Reexamined  

E-print Network

A high-statistics measurement of bremsstrahlung emitted in the alpha decay of 210Po has been performed, which allows to follow the photon spectra up to energies of ~ 500 keV. The measured differential emission probability is in good agreement with our theoretical results obtained within the quasi classical 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.

H. Boie; H. Scheit; U. D. Jentschura; F. Köck; M. Lauer; A. I. Milstein; I. S. Terekhov; D. Schwalm

2007-06-14

397

Bremsstrahlung in alpha-Decay Revisited  

E-print Network

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

Boie, H; Jentschura, U D; Köck, F; Lauer, M; Milstein, A I; Terekhov, I S; Schwalm, D

2007-01-01

398

Fan-less long range alpha detector  

DOEpatents

A fan-less long range alpha detector is disclosed which operates by using an electrical field between a signal plane and the surface or substance to be monitored for air ions created by collisions with alpha radiation. Without a fan, the detector can operate without the possibility of spreading dust and potential contamination into the atmosphere. A guard plane between the signal plane and the electrically conductive enclosure and maintained at the same voltage as the signal plane, reduces leakage currents. The detector can easily monitor soil, or other solid or liquid surfaces. 2 figures.

MacArthur, D.W.; Bounds, J.A.

1994-05-10

399

Lyman-alpha Absorption from Heliosheath Neutrals  

Microsoft Academic Search

We assess what information HST observations of stellar Ly-alpha lines can\\u000aprovide on the heliosheath, the region of the heliosphere between the\\u000atermination shock and heliopause. To search for evidence of heliosheath\\u000aabsorption, we conduct a systematic inspection of stellar Ly-alpha lines\\u000areconstructed after correcting for ISM absorption (and\\u000aheliospheric\\/astrospheric absorption, if present). Most of the stellar lines\\u000aare well

Brian E. Wood; Vladislav V. Izmodenov; Jeffrey L. Linsky; Yury G. Malama

2006-01-01

400

Intense Ly-alpha emission from Uranus  

NASA Technical Reports Server (NTRS)

The existence of intense atomic hydrogen Ly-alpha emission from Uranus is demonstrated here by utilizing the monochromatic imaging capabilities of the International Ultraviolet Explorer (IUE) spectrograph. Observations show increased emission in the vicinity of Uranus superimposed on the geocoronal/interplanetary background. If resonant scattering of solar Ly-alpha is the source of the 1.6 + or - 0.4 kR disk averaged brightness, then very high column densities of atomic H above the absorbing methane are required. Precipitation of trapped charged particles, i.e., aurora, could explain the emissions. This would imply a planetary magnetic field.

Durrance, S. T.; Moos, H. W.

1982-01-01

401

Advanced simulation code for alpha spectrometry  

E-print Network

A Monte Carlo code, known as AASI, is developed for simulating energy spectra in alpha spectrometry. The code documented here is a comprehensive package where all the major processes affecting the spectrum are included. A unique feature of the code is its ability to take into account coincidences between the particles emitted from the source. Simulations and measurements highlight the importance of coincidences in high-resolution alpha spectrometry. To show the validity of the simulated results, comparisons with measurements and other simulation codes are presented.

T. Siiskonen; R. Pollanen

2005-05-04

402

Galphaq binds to p110alpha/p85alpha phosphoinositide 3-kinase and displaces Ras.  

PubMed

Several studies have reported that activation of G(q)-coupled receptors inhibits PI3K (phosphoinositide 3-kinase) signalling. In the present study, we used purified proteins to demonstrate that Galpha(q) directly inhibits p110alpha/p85alpha PI3K in a GTP-dependent manner. Activated Galpha(q) binds to the p110alpha/p85alpha PI3K with an apparent affinity that is seven times stronger than that for Galpha(q).GDP as measured by fluorescence spectroscopy. In contrast, Galpha(q) did not bind to the p110gamma PI3K. Fluorescence spectroscopy experiments also showed that Galpha(q) competes with Ras, a PI3K activator, for binding to p110alpha/p85alpha. Interestingly, co-precipitation studies using deletion mutants showed that Galpha(q) binds to the p85-binding domain of p110alpha and not to the Ras-binding domain. Expression of constitutively active Galpha(q)Q209L in cells inhibited Ras activation of the PI3K/Akt pathway but had no effect on Ras/Raf/MEK [MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase] signalling. These results suggest that activation of G(q)-coupled receptors leads to increased binding of Galpha(q).GTP to some isoforms of PI3K, which might explain why these receptors inhibit this signalling pathway in certain cell types. PMID:16268778

Ballou, Lisa M; Chattopadhyay, Mohar; Li, Yan; Scarlata, Suzanne; Lin, Richard Z

2006-03-15

403

Genomic organization of the bovine alpha-S1 casein gene.  

PubMed Central

We report the sequence of the complete bovine alpha-s1 casein gene eludicating for the first time the genomic organization of an alpha-s type casein gene. Extending over 17508 bp the gene is split into 19 exons, ranging in size from 24 bp to 385 bp. Except for the translational stop codon not a single coding triplet of the alpha-s1 reading frame is disrupted by any of the splice junctions, which all confirm to known splice consensus sequences. Nine out of 16 coding exons begin with a 'GAX' codon, specific for glutamate. Splicing of this codon from exon 10 to the preceding exon creates a major phosphorylation site. An intron-exon-intron stretch of 154 bp comprising exons 10 and 13 is found precisely duplicated. Associated with the gene, copies of 8 atriodactyla retroposons are found, 6 of which are interspersed into the sequences of the three longest introns. We discuss the possibility that three functional parts of the gene have been recruited and evolutionary conserved at a time before gene diversification gave rise to the separate evolution of alpha- and beta-type casein-genes. PMID:1658736

Koczan, D; Hobom, G; Seyfert, H M

1991-01-01

404

Phlebotomus papatasi and Leishmania major parasites express alpha-amylase and alpha-glucosidase.  

PubMed

Alpha-amylase and alpha-glucosidase activities were found in homogenates of young, unfed male and female Phlebotomus papatasi and in gut and salivary gland preparations. A significant increase in both enzyme activities in females and of alpha-amylase in males was recorded for flies that had fed overnight on a plant (Capparis spinosa). After plant feeding, alpha-amylase activity was relatively lower in female salivary glands and higher in guts, while in the males the activity in the salivary glands had increased. Alpha-glucosidase activity increased in guts of both sexes and in the salivary glands of the females. In addition, alpha-amylase activity was found in preparations of Leishmania major and L. infantum promastigotes, but not in those of L. donovani or L. tropica. Alpha-glucosidase activity was present in promastigote preparations of L. major, L. infantum, L. donovani, L. braziliensis, Crithidia fasciculata and Herpetomonas muscarum. It was lacking in similar preparations of L. tropica, Sauroleishmania agamae or Leptomonas seymouri. The growth rate of L. major promastigotes in medium supplemented with starch or with glucose was similar and it was significantly higher than in glucose poor medium. In this study, we demonstrate that P. papatasi and L. major possess the enzymes for hydrolyzing starch grains that are included in the plant tissue-diet of the sand flies. PMID:11164750

Jacobson, R L; Schlein, Y

2001-01-15

405

Alanine Aminotransferase Elevation during Peginterferon Alpha-2a or Alpha-2b plus Ribavirin Treatment  

PubMed Central

Alanine aminotransferase (ALT) elevation was occassionally observed during the treatment with combination peginterferon alpha plus ribavirin. Two forms of peginterferon are currently available as a standard of care with or without direct-acting antivirals against hepatitis C virus (HCV). Until the appearance of interferon-sparing regimen, peginterferon alpha plus ribavirin will play a central role in the eradication of HCV. In the present study, we compared ALT elevations in response to peginterferon alpha-2a plus ribavirin or peginterferon alpha-2b plus ribavirin in HCV genotype-1-infected patients. There were no significant differences in ALT elevations between treatments with the two peginterferons, but in a comparison of the proportions of patients with transient ALT elevation from baseline between the two groups, transient ALT elevation was observed more in sustained virological response (SVR) patients treated with peginterferon alpha-2a than with peginterferon alpha-2b. However, no patients discontinued treatment due to ALT elevation. Patients with transient ALT elevation from baseline during the treatment had less favorable IL28B rs8099917 genotype in the peginterferon alpha-2b group. Patients achieving SVR tended to have lower ALT levels, although some had persistent ALT elevation during treatment. In conclusion, clinicians should pay attention to possible ALT elevation during the treatment of chronic hepatitis C patients. PMID:23801888

Nakamura, Masato; Kanda, Tatsuo; Miyamura, Tatsuo; Wu, Shuang; Nakamoto, Shingo; Yokosuka, Osamu

2013-01-01

406

Far-Infrared and Millimeter Continuum Studies of K Giants: Alpha Boo and Alpha Tau  

E-print Network

We have imaged two normal, non-coronal, infrared-bright K giants, Alpha Tau and Alpha Boo, in the 1.4-mm and 2.8-mm continuum using the Berkeley Illinois Maryland Association millimeter array. These stars have been used as important absolute calibrators for several infrared infrared satellites. Our goals are: (1) to establish whether these stars radiate as simple photospheres or possess long-wavelength chromospheres; and (2) to make a connection between millimeter wave and far-infrared absolute flux calibrations. To accomplish these goals we also present Infrared Space Observatory Long Wavelength Spectrometer measurements of both these K giants. The far-infrared and millimeter continuum radiation is produced in the vicinity of the temperature minimum in Alpha Tau and Alpha Boo. We find that current photospheric models predict fluxes in reasonable agreement with those observed for wavelengths which sample the upper photosphere, namely <=125 microns in Alpha Tau and Alpha Boo. We clearly detect chromospheric radiation from both stars by 2.8mm (by 1.4mm in the case of Alpha Boo). Only additional observations can determine precisely where beyond 125 microns the purely radiative models fail. Until then, purely radiative models for these stars can only be used with confidence for calibration purposes below 125 microns.

Martin Cohen; Duane F. Carbon; William J. Welch; Tanya Lim; Bernhard Schulz; A. D. McMurry; James R. Forster; David Goorvitch; .

2005-02-24

407

Preparation of (R) and (S) alpha methyldopa from a chiral hydantoin containing the alpha phenylethyl group.  

PubMed

Chiral hydantoin (S)-1 was prepared in good yield from phenyl isocyanate and N-[(S)-alpha-phenylethyl]glycinate, (S)-3. Enolate (S)-1-Li was methylated in high yield and good diastereoselectivity. In contrast, a second alkylation reaction of methylated enolate (S)-4-Li proceeded with essentially no diastereoselectivity. Nevertheless, dialkylated hydantoins, (S,S)-7 and (S,R)-7, could be readily separated by flash chromatography and subsequent hydrolysis of either derivative afforded the desired (S)-L-alpha-methyldopa or (R)-D-alpha-methyldopa in good yield. PMID:11835557

León-Romo, José Luis; Virues, Claudia I; Aviña, Judit; Regla, Ignacio; Juaristi, Eusebio

2002-01-01

408

Extraction of alpha_s from the energy evolution of jet fragmentation functions at low z  

E-print Network

A novel method to extract the QCD coupling alpha_s from the energy evolution of the moments of the parton-to-hadron fragmentation functions at low fractional hadron momentum z, is presented. The evolution of the moments (multiplicity, peak, width, skewness) of the charged-hadron distribution in jets is computed at NMLLA+NLO* accuracy and compared to the experimental deep-inelastic e-p data. Values of the strong coupling constant at the Z pole are obtained, alpha_s(m_Z) = 0.119 +/- 0.010, in excellent numerical agreement with the current world average determined using other methods at the same level of accuracy.

d'Enterria, David

2014-01-01

409

The alpha-form of the hydroxides of bivalent metals  

NASA Technical Reports Server (NTRS)

X-ray analyses were made of the hydroxides of the bivalent metals. The freshly pptd. hydroxide is usually in the alpha-form, which on standing is converted to another form or other forms. The alpha and c grating dimensions of the alpha-form and the C6-type of Co, Zn, C, Co-Zn and Ni-Zn hydroxides are tabulated. Ni hydroxide does not exhibit an alpha-form. The alpha-Co(OH)2, the blue form, is stabilized by sugar or by the higher alcohols: these compounds do not stabilize alpha-Zn(OH)2.

Feitknecht, W.

1984-01-01

410

Synthesis of 16 alpha-/sub 3/H androgen and estrogen substrates for 16 alpha-hydroxylase  

SciTech Connect

The synthesis of 16 alpha-/sup 3/H androgens and estrogens is described. 1-(/sup 3/H)-Acetic acid in the presence of zinc dust reacts with 16 alpha-bromo-17-ketosteroids to produce 16 alpha-/sup 3/H-17-ketosteroids. This chemical reaction was used to prepare 16 alpha-/sup 3/H-dehydroepiandrosterone (I) and 16 alpha-/sub 4/H-estrone acetate (XI) from 16 alpha-bromo-dehydroepiandrosterone (X) and from 16 alpha-bromo-estrone acetate (XII), respectively. Using appropriate microbiological techniques, it was possible to convert these radiolabelled substrates into 16 alpha-/sup 3/H-androstenedione (II) and 16 alpha-/sup 3/H-estradiol-17 beta (VII). 16 alpha-/sup 3/H-Estrone (VI) was obtained by the chemical hydrolysis of 16 alpha-/sup 3/H-estrone acetate. The label distribution as determined by microbiological 16 alpha-hydroxylations indicated a specific labelling of 77% for androgens and 65% for estrogens in the 16 alpha position. These substrates can be used for measuring the 16 alpha hydroxylase activity, an important step in the biosynthesis of estriol (VIII) and estetrol (IX).

Cantineau, R.; Kremers, P.; De Graeve, J.; Cornelis, A.; Laszlo, P.; Gielen, J.E.; Lambotte, R.

1981-02-01

411

The interaction between menstrual cycle, Tumour Necrosis Factor alpha receptors and sex hormones in healthy non-obese women - results from an observational study.  

PubMed

There is growing evidence that TNF-alpha and its two receptors play an important role in hormonal regulation, metabolism, inflammation and cancer. The biological effects of TNF-alpha are mediated by two receptors, p55 and p75. The aim of this study was to analyze serum concentrations of p55 and p75 and hormonal status in healthy women during the normal menstrual cycle. Eight women aged 20-22 with regular menstrual cycles were scheduled for examination on 3(rd) , 8(th) , 14(th) and 25(th) day of their menstrual cycle. We only observed a positive correlation of p75 subunit with prolactin level (correlation coefficient 0.417; p=0.0116) and negative correlation with insulin level (correlation coefficient -0.35; p=0.032) and HOMAIR insulin resistance index correlation coefficient 0.39; p=0.0185). Furthermore, a negative correlation of p55/p75 ratio with prolactin (correlation coefficient -0.42; p=0.0101) and a positive correlations of p55/p75 ratio with insulin level (correlation coefficient 0.43; p=0.008) and HOMAIR insulin resistance factor correlation coefficient 0.45; p=0.0065) were found. PMID:25292131

Rzymski, Pawe?; Wilczak, Maciej; Malinger, Anna; W?oszczak-Szubzda, Anna; Jarosz, Miros?aw Jerzy; Opala, Tomasz

2014-09-01

412

Alpha track density using a semiconductor detector  

E-print Network

in the film corresponding to the damage produced in the dielectric by alpha particle passage and etching enhancement. A xenon flash lamp was used as the blue light source (467nm) for a CN densitometer, and a cadmium sulfide (CdS) photoconductive semiconductor...

Hamilton, Ian Scott

2012-06-07

413

Alpha 97: Basic Education and Institutional Environments.  

ERIC Educational Resources Information Center

This document was published by Alpha, a research program specializing in alternative, experimental approaches to adult basic education. It is an attempt to widen the field and examine the relationship between the micro and macro levels, between the diversity of different practices and the major policy orientations that foster or limit this…

Hautecoeur, Jean-Paul, Ed.

414

Synthesis of stabilized alpha-helical peptides.  

PubMed

Stabilized alpha-helical (SAH) peptides are valuable laboratory tools to explore important protein-protein interactions. Whereas most peptides lose their secondary structure when isolated from the host protein, stapled peptides incorporate an all-hydrocarbon "staple" that reinforces their natural alpha-helical structure. Thus, stapled peptides retain their functional ability to bind their native protein targets and serve multiple experimental uses. First, they are useful for structural studies such as NMR or crystal structures that map and better define binding sites. Second, they can be used to identify small molecules that specifically target that interaction site. Third, stapled peptides can be used to test the importance of specific amino acid residues or posttranslational modifications to the binding. Fourth, they can serve as structurally competent bait to identify novel binding partners to specific alpha-helical motifs. In addition to markedly improved alpha-helicity, stapled peptides also display resistance to protease cleavage and enhanced cell permeability. Most importantly, they are useful for intracellular experiments that explore the functional consequences of blocking particular protein interactions. Because of their remarkable stability, stapled peptides can be applied to whole-animal, in vivo studies. Here we describe a protocol for the synthesis of a peptide that incorporates an all-hydrocarbon "staple" employing a ring-closing olefin metathesis reaction. With proper optimization, stapled peptides can be a fundamental, accurate laboratory tool in the modern chemical biologist's armory. PMID:25030922

Bernal, Federico; Katz, Samuel G

2014-01-01

415

H LY Alpha Emission From Neptune  

Microsoft Academic Search

Two attempts have been made to date with IUE to detect th: H Ly-alpha emission from Neptune, using US2 shifts in 1983 and US1 shift in August 1986. Using the same observing technique which detected the aurora and electroglow on Uranus at an average brightness (over 4 year's time) of 1400 Rayleighs no emission has been detected from Neptune with

John T. Clarke

1987-01-01

416

Lyman Alpha Galaxies and Galaxy Formation Scenarios  

Microsoft Academic Search

The Large Area Lyman Alpha survey has successfully identified the population of young Lyalpha emitting galaxies predicted over 35 years ago. High equivalent widths of Lyalpha in these sources suggest that they are a very young (age < 10^7 years), metal poor, population of stars, making them very interesting objects for understanding galaxy formation. With two nights of Magellan+IMACS time,

James Rhoads; Sangeeta Malhotra

2005-01-01

417

Radioluminescence yield of alpha particles in air  

NASA Astrophysics Data System (ADS)

Alpha particles can be detected by measuring the radioluminescence light which they induce when absorbed in air. The light is emitted in the near ultraviolet region by nitrogen molecules excited by secondary electrons. The accurate knowledge of the radioluminescence yield is of utmost importance for novel radiation detection applications utilizing this secondary effect. Here, the radioluminescence yield of an alpha particle is investigated as a function of energy loss in air for the first time. Also, the total radioluminescence yield of the particle is measured with a carefully calibrated ^{239}Pu emitter used in the experiments. The obtained results consistently indicate that alpha particles generate 19±3 photons per one MeV of energy released in air at normal pressure (temperature 22°C, relative humidity 43%) and the dependence is found to be linear in the studied energy range from 0.3 MeV to 5.1 MeV. The determined radioluminescence yield is higher than previously reported for alpha particles and similar to the radioluminescence yield of electrons at comparable energies. This strengthens the evidence that the luminescence induced by charged particles is mostly proportional to the energy loss in the media and not very sensitive to the type of primary particle.

Sand, J.; Ihantola, S.; Peräjärvi, K.; Toivonen, H.; Toivonen, J.

2014-05-01

418

Are Damped Lyman alpha Systems Rotating Disks ?  

E-print Network

We report on high spectral resolution observations of five damped Lyman alpha systems whose line velocity profiles and abundances are analyzed. By combining these data with information from the literature, we study the kinematics of the low and high ionization phases of damped systems and discuss the possibility that part of the motions is due to rotation.

Cedric Ledoux; Patrick Petitjean; Jacqueline Bergeron

1998-01-26

419

The Ups and Downs of Alpha Centauri  

NASA Astrophysics Data System (ADS)

The nearby Alpha Centauri triple system has two solar-type stars in a relatively close orbit (20 au separation), and a dim red dwarf companion -- Proxima -- about 10,000 au away, on the Sun-ward side of the group. The heaviest star -- Alpha Cen A -- is a close twin of the Sun. Its slightly less massive companion -- Alpha Cen B -- is a K-type dwarf, and is the closest star thought to host an exoplanet (Earth-sized, but in a much tighter orbit). The close pair has been scrutinized for more than a decade in X-rays by XMM and Chandra, on a semiannual basis since 2003 and 2005, respectively. However, in recent years only Chandra has been able to cleanly separate the pair, which are approaching closest separation on the sky (only a few arcseconds) in their 80-year orbit. For the past 3 years, the HST STIS spectrograph has joined the crowd, also capturing FUV snapshots of the pair every six months. The Alpha Cen stars provide an important complement to long-term studies of the Sun at high energies. The K-star has displayed a clear 8-year cycle in recent years, while the G-star remains mired in a Maunder-like minimum.

Ayres, Thomas R.

2013-07-01

420

Transformer Recharging with Alpha Channeling in Tokamaks  

SciTech Connect

Transformer recharging with lower hybrid waves in tokamaks can give low average auxiliary power if the resistivity is kept high enough during the radio frequency (rf) recharging stage. At the same time, operation in the hot ion mode via alpha channeling increases the effective fusion reactivity. This paper will address the extent to which these two large cost saving steps are compatible. __________________________________________________

N.J. Fisch

2009-12-21

421

EEG alpha power and creative ideation.  

PubMed

Neuroscientific studies revealed first insights into neural mechanisms underlying creativity, but existing findings are highly variegated and often inconsistent. Despite the disappointing picture on the neuroscience of creativity drawn in recent reviews, there appears to be robust evidence that EEG alpha power is particularly sensitive to various creativity-related demands involved in creative ideation. Alpha power varies as a function of creativity-related task demands and the originality of ideas, is positively related to an individuals' creativity level, and has been observed to increase as a result of creativity interventions. Alpha increases during creative ideation could reflect more internally oriented attention that is characterized by the absence of external bottom-up stimulation and, thus, a form of top-down activity. Moreover, they could indicate the involvement of specific memory processes such as the efficient (re-)combination of unrelated semantic information. We conclude that increased alpha power during creative ideation is among the most consistent findings in neuroscientific research on creativity and discuss possible future directions to better understand the manifold brain mechanisms involved in creativity. PMID:23246442

Fink, Andreas; Benedek, Mathias

2014-07-01

422

Prediction of {alpha}-decay half-lives and Q{sub {alpha}} values of superheavy nuclei by a global potential for {alpha} + nucleus systems  

SciTech Connect

An approach we have proposed recently for calculation of Q{sub {alpha}} energy and decay half-life T{sub 1/2}{sup {alpha}} on the {alpha} decay of radioactive heavy ions is applied to the evaluation of these two important parameters for the nuclei in the superheavy region Z = 112-118 for which experimental data are not available. It is shown that the {alpha} + nucleus potential represented by an exactly solvable potential used in the calculation could be expressed in terms of proton (Z) and neutron (N) numbers of the {alpha} emitter so that varieties of {alpha}-emitting nuclei differing in their Z and N values could be addressed for their decay properties without the help of any adjustable parameter and the results of Q{sub {alpha}} and T{sub 1/2}{sup {alpha}} for a nucleus are estimated without any prior knowledge of any one of these quantities. This procedure to obtain the values of Q{sub {alpha}} and T{sub 1/2}{sup {alpha}} works well to reproduce the known experimental results for superheavy nuclei and hence, the procedure is expected to provide proper information about these parameters in experiments on {alpha} decay of new nuclei in the superheavy region.

Sahu, Basudeb [Department of Physics, North Orissa University, Baripada-757003 (India)

2011-09-15

423

Involvement of the clock gene Rev-erb alpha in the regulation of glucagon secretion in pancreatic alpha-cells.  

PubMed

Disruption of pancreatic clock genes impairs pancreatic beta-cell function, leading to the onset of diabetes. Despite the importance of pancreatic alpha-cells in the regulation of glucose homeostasis and in diabetes pathophysiology, nothing is known about the role of clock genes in these cells. Here, we identify the clock gene Rev-erb alpha as a new intracellular regulator of glucagon secretion. Rev-erb alpha down-regulation by siRNA (60-70% inhibition) in alphaTC1-9 cells inhibited low-glucose induced glucagon secretion (p<0.05) and led to a decrease in key genes of the exocytotic machinery. The Rev-erb alpha agonist GSK4112 increased glucagon secretion (1.6 fold) and intracellular calcium signals in alphaTC1-9 cells and mouse primary alpha-cells, whereas the Rev-erb alpha antagonist SR8278 produced the opposite effect. At 0.5 mM glucose, alphaTC1-9 cells exhibited intrinsic circadian Rev-erb alpha expression oscillations that were inhibited by 11 mM glucose. In mouse primary alpha-cells, glucose induced similar effects (p<0.001). High glucose inhibited key genes controlled by AMPK such as Nampt, Sirt1 and PGC-1 alpha in alphaTC1-9 cells (p<0.05). AMPK activation by metformin completely reversed the inhibitory effect of glucose on Nampt-Sirt1-PGC-1 alpha and Rev-erb alpha. Nampt inhibition decreased Sirt1, PGC-1 alpha and Rev-erb alpha mRNA expression (p<0.01) and glucagon release (p<0.05). These findings identify Rev-erb alpha as a new intracellular regulator of glucagon secretion via AMPK/Nampt/Sirt1 pathway. PMID:23936124

Vieira, Elaine; Marroquí, Laura; Figueroa, Ana Lucia C; Merino, Beatriz; Fernandez-Ruiz, Rebeca; Nadal, Angel; Burris, Thomas P; Gomis, Ramon; Quesada, Ivan

2013-01-01

424

Elevated expression of alphaA- and alphaB-crystallins in streptozotocin-induced diabetic rat.  

PubMed

alpha-Crystallin, a predominant protein of the ocular lens, is composed of two subunits, alphaA and alphaB. Of these, alphaB-crystallin has been shown to present widely in non-lenticular tissues while alphaA-crystallin is largely lens-specific. Although, expression of alphaB-crystallin is elevated under various stress and pathological conditions, yet its physiological significance remained unknown. Some studies suggest that the expression of alphaB-crystallin gene is related to oxidative stress. Persistent hyperglycemia during uncontrolled diabetes is known to cause oxidative stress, which has been implicated in various secondary complications of diabetes. Hence, expression of alphaA- and alphaB-crystallins in various tissues of streptozotocin (STZ)-induced diabetic Wistar-NIN rats was investigated by RT-PCR and immunoblotting. While expression of alphaB-crystallin was noted in the wide range of tissues examined in the study, alphaA-crystallin expression was detected only in lens and retina. Interestingly, alphaB-crystallin expression was elevated in lens, heart, muscle, and brain, but decreased in adipose tissue of diabetic rats compared to control rats. alphaA-Crystallin expression was increased in retina of diabetic rat. Increased oxidative stress appears to be a major stimulus for the enhanced expression of alphaA- and alphaB-crystallins in the tissues of diabetic rats and elevated expression of alpha-crystallin may have a protective role against metabolic stress. Interestingly, feeding of curcumin, a dietary antioxidant, to diabetic rats attenuated the enhanced expression of alphaB-crystallin. The results indicate that elevated expression of alpha-crystallins in some tissues may have implications in pathophysiology of diabetic complications. PMID:16309625

Kumar, P Anil; Haseeb, Abdul; Suryanarayana, P; Ehtesham, Nasreen Z; Reddy, G Bhanuprakash

2005-12-15

425

Involvement of the Clock Gene Rev-erb alpha in the Regulation of Glucagon Secretion in Pancreatic Alpha-Cells  

PubMed Central

Disruption of pancreatic clock genes impairs pancreatic beta-cell function, leading to the onset of diabetes. Despite the importance of pancreatic alpha-cells in the regulation of glucose homeostasis and in diabetes pathophysiology, nothing is known about the role of clock genes in these cells. Here, we identify the clock gene Rev-erb alpha as a new intracellular regulator of glucagon secretion. Rev-erb alpha down-regulation by siRNA (60–70% inhibition) in alphaTC1-9 cells inhibited low-glucose induced glucagon secretion (p<0.05) and led to a decrease in key genes of the exocytotic machinery. The Rev-erb alpha agonist GSK4112 increased glucagon secretion (1.6 fold) and intracellular calcium signals in alphaTC1-9 cells and mouse primary alpha-cells, whereas the Rev-erb alpha antagonist SR8278 produced the opposite effect. At 0.5 mM glucose, alphaTC1-9 cells exhibited intrinsic circadian Rev-erb alpha expression oscillations that were inhibited by 11 mM glucose. In mouse primary alpha-cells, glucose induced similar effects (p<0.001). High glucose inhibited key genes controlled by AMPK such as Nampt, Sirt1 and PGC-1 alpha in alphaTC1-9 cells (p<0.05). AMPK activation by metformin completely reversed the inhibitory effect of glucose on Nampt-Sirt1-PGC-1 alpha and Rev-erb alpha. Nampt inhibition decreased Sirt1, PGC-1 alpha and Rev-erb alpha mRNA expression (p<0.01) and glucagon release (p<0.05). These findings identify Rev-erb alpha as a new intracellular regulator of glucagon secretion via AMPK/Nampt/Sirt1 pathway. PMID:23936124

Vieira, Elaine; Marroqui, Laura; Figueroa, Ana Lucia C.; Merino, Beatriz; Fernandez-Ruiz, Rebeca; Nadal, Angel; Burris, Thomas P.; Gomis, Ramon; Quesada, Ivan

2013-01-01

426

Surrogate ratio method in the actinide region using the ({alpha},{alpha}{sup '}f) reaction  

SciTech Connect

In the Surrogate Method, the measured decay probability of a compound nucleus formed via a direct reaction is used to extract the cross section for a reaction with a different entrance channel that proceeds through the same compound nucleus. An extension of the Surrogate Method, the Surrogate Ratio Method (SRM), uses a ratio of measured decay probabilities to infer an unknown cross section relative to a known one. To test the SRM we compare the direct-reaction-induced fission probability ratio of {sup 234}U({alpha},{alpha}{sup '}f) to {sup 236}U({alpha},{alpha}{sup '}f) with the ratio of cross sections of {sup 233}U(n,f) to {sup 235}U(n,f). These ratios were found to be in agreement over an equivalent neutron energy range of 0.4-18 MeV.

Lesher, S. R. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Department of Physics, University of Richmond, Richmond, Virginia 23173 (United States); Burke, J. T.; Bernstein, L. A.; Dietrich, F. S.; Escher, J. E.; Moody, K. J.; Scielzo, N. D. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Ai, H. [Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520 (United States); Beausang, C. W. [Department of Physics, University of Richmond, Richmond, Virginia 23173 (United States); Bleuel, D. L.; Wiedeking, M. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Clark, R. M.; Fallon, P.; Gibelin, J.; Lee, I. Y.; Macchiavelli, A. O.; McMahan, M. A.; Phair, L.; Rodriguez-Vieitez, E. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Goldblum, B. L. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Department of Nuclear Engineering, University of California, Berkeley, California 94720 (United States)] (and others)

2009-04-15

427

Identifying Bearing Rotordynamic Coefficients using an Extended Kalman Filter  

NASA Technical Reports Server (NTRS)

An Extended Kalman Filter is developed to estimate the linearized direct and indirect stiffness and damping force coefficients for bearings in rotor-dynamic applications from noisy measurements of the shaft displacement in response to imbalance and impact excitation. The bearing properties are modeled as stochastic random variables using a Gauss-Markov model. Noise terms are introduced into the system model to account for all of the estimation error, including modeling errors and uncertainties and the propagation of measurement errors into the parameter estimates. The system model contains two user-defined parameters that can be tuned to improve the filter s performance; these parameters correspond to the covariance of the system and measurement noise variables. The filter is also strongly influenced by the initial values of the states and the error covariance matrix. The filter is demonstrated using numerically simulated data for a rotor-bearing system with two identical bearings, which reduces the number of unknown linear dynamic coefficients to eight. The filter estimates for the direct damping coefficients and all four stiffness coefficients correlated well with actual values, whereas the estimates for the cross-coupled damping coefficients were the least accurate.

Miller, Brad A.; Howard, Samuel A.

2008-01-01

428

Identifying Bearing Rotodynamic Coefficients Using an Extended Kalman Filter  

NASA Technical Reports Server (NTRS)

An Extended Kalman Filter is developed to estimate the linearized direct and indirect stiffness and damping force coefficients for bearings in rotor dynamic applications from noisy measurements of the shaft displacement in response to imbalance and impact excitation. The bearing properties are modeled as stochastic random variables using a Gauss-Markov model. Noise terms are introduced into the system model to account for all of the estimation error, including modeling errors and uncertainties and the propagation of measurement errors into the parameter estimates. The system model contains two user-defined parameters that can be tuned to improve the filter's performance; these parameters correspond to the covariance of the system and measurement noise variables. The filter is also strongly influenced by the initial values of the states and the error covariance matrix. The filter is demonstrated using numerically simulated data for a rotor bearing system with two identical bearings, which reduces the number of unknown linear dynamic coefficients to eight. The filter estimates for the direct damping coefficients and all four stiffness coefficients correlated well with actual values, whereas the estimates for the cross-coupled damping coefficients were the least accurate.

Miller, Brad A.; Howard, Samuel A.

2008-01-01

429

Viscosity Coefficient Curve Fits for Ionized Gas Species Grant Palmer  

NASA Technical Reports Server (NTRS)

Viscosity coefficient curve fits for neutral gas species are available from many sources. Many do a good job of reproducing experimental and computational chemistry data. The curve fits are usually expressed as a function of temperature only. This is consistent with the governing equations used to derive an expression for the neutral species viscosity coefficient. Ionized species pose a more complicated problem. They are subject to electrostatic as well as intermolecular forces. The electrostatic forces are affected by a shielding phenomenon where electrons shield the electrostatic forces of positively charged ions beyond a certain distance. The viscosity coefficient for an ionized gas species is a function of both temperature and local electron number density. Currently available curve fits for ionized gas species, such as those presented by Gupta/Yos, are a function of temperature only. What they did was to assume an electron number density. The problem is that the electron number density they assumed was unrealistically high. The purpose of this paper is two-fold. First, the proper expression for determining the viscosity coefficient of an ionized species as a function of both temperature and electron number density will be presented. Then curve fit coefficients will be developed using the more realistic assumption of an equilibrium electron number density. The results will be compared against previous curve fits and against highly accurate computational chemistry data.

Palmer, Grant; Arnold, James O. (Technical Monitor)

2001-01-01

430

Model Selection for Cox Models with Time-Varying Coefficients  

PubMed Central

Summary Cox models with time-varying coefficients offer great flexibility in capturing the temporal dynamics of covariate effects on right censored failure times. Since not all covariate coefficients are time-varying, model selection for such models presents an additional challenge, which is to distinguish covariates with time-varying coefficient from those with time-independent coefficient. We propose an adaptive group lasso method that not only selects important variables but also selects between time-independent and time-varying specifications of their presence in the model. Each covariate effect is partitioned into a time-independent part and a time-varying part, the latter of which is characterized by a group of coefficients of basis splines without intercept. Model selection and estimation are carried out through a fast, iterative group shooting algorithm. Our approach is shown to have good properties in a simulation study that mimics realistic situations with up to 20 variables. A real example illustrates the utility of the method. PMID:22506825

Yan, Jun; Huang, Jian

2011-01-01

431

The Inertial Coefficients of an Airship in a Frictionless Fluid  

NASA Technical Reports Server (NTRS)

This report deals with the investigation of the apparent inertia of an airship hull. The exact solution of the aerodynamical problem has been studied for hulls of various shapes and special attention has been given to the case of an ellipsoidal hull. In order that the results for this last case may be readily adapted to other cases, they are expressed in terms of the area and perimeter of the largest cross section perpendicular to the direction motion by means of a formula involving a coefficient K which varies only slowly when the shape of the hull is changed, being 0.637 for a circular or elliptic disk, 0.5 for a sphere, and about 0.25 for a spheroid of fineness ratio 7. For rough purposes it is sufficient to employ the coefficients, originally found for ellipsoids, for hulls otherwise shaped. When more exact values of the inertia are needed, estimates may be based on a study of the way in which K varies with different characteristics and for such a study the new coefficient possesses some advantage over one which is defined with reference to the volume of fluid displaced. The case of rotation of an airship hull has been investigated also and a coefficient has been defined with the same advantages as the corresponding coefficient for rectilinear motion.

Bateman, H

1924-01-01

432

LIMB-DARKENING COEFFICIENTS FOR ECLIPSING WHITE DWARFS  

SciTech Connect

We present extensive calculations of linear and nonlinear limb-darkening coefficients as well as complete intensity profiles appropriate for modeling the light-curves of eclipsing white dwarfs. We compute limb-darkening coefficients in the Johnson-Kron-Cousins UBVRI photometric system as well as the Large Synoptic Survey Telescope (LSST) ugrizy system using the most up to date model atmospheres available. In all, we provide the coefficients for seven different limb-darkening laws. We describe the variations of these coefficients as a function of the atmospheric parameters, including the effects of convection at low effective temperatures. Finally, we discuss the importance of having readily available limb-darkening coefficients in the context of present and future photometric surveys like the LSST, Palomar Transient Factory, and the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS). The LSST, for example, may find {approx}10{sup 5} eclipsing white dwarfs. The limb-darkening calculations presented here will be an essential part of the detailed analysis of all of these systems.

Gianninas, A.; Strickland, B. D.; Kilic, Mukremin [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks St., Norman, OK 73019 (United States)] [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks St., Norman, OK 73019 (United States); Bergeron, P., E-mail: alexg@nhn.ou.edu, E-mail: benstrickland@ou.edu, E-mail: kilic@ou.edu, E-mail: bergeron@astro.umontreal.ca [Departement de Physique, Universite de Montreal, C.P. 6128, Succ. Centre-Ville, Montreal, Quebec H3C 3J7 (Canada)

2013-03-20

433

Running alpha(s) from Landau-gauge gluon and ghost correlations  

E-print Network

We estimate the running coupling constant of the strong interactions within the nonperturbative framework of lattice QCD in Landau gauge. Our calculation is based on the ghost-gluon vertex which in the particular case of Landau gauge allows for a definition of alpha(s) in a MOM scheme solely in terms of the gluon and ghost dressing functions. As a first step we investigate the zero and two-flavour case and report here on preliminary results.

A. Sternbeck; E. -M. Ilgenfritz; K. Maltman; M. Müller-Preussker; L. von Smekal; A. G. Williams

2007-10-16

434

Synthesis of some new steroidal [16alpha,17alpha-d]-isoxazolines.  

PubMed

Regioselective synthesis of novel steroidal anti-inflammatory ante drug analogues, viz., [16alpha,17alpha-d]-isoxazolines 1(a-h) and 2(a-h) prepared in a single step in good yield by the reaction of 16-dehydropregnenolone acetate (16-DPA) 1 or related 21-chloro-20-oxopregnane 2 with various aldoximes (a-h) in presence of chloramine-T in refluxing ethanol. PMID:15894032

Chowdhury, Pritish; Das, Archana Moni; Goswami, Papori

2005-07-01

435

Kinetics of chaperoning of dithiothreitol-denatured alpha-lactalbumin by alpha-crystallin.  

PubMed

Molecular chaperones prevent the aggregation of partially folded or misfolded forms of protein. alpha-Crystallin performs such a function in the ocular lens. Dynamic light scattering (DLS) measurements were performed to gain insight into the kinetics and mechanism of alpha-crystallin chaperoning. Experiments were conducted as a function of alpha-lactalbumin concentration as well as the alpha-crystallin/alpha-lactalbumin ratio over a 24 h period. In the particle distribution patterns the lactalbumin concentration was partitioned into three compartments: (a) monomeric free lactalbumin; (b) lactalbumin in the chaperoning complex; and (c) lactalbumin aggregates. DLS intensities were converted to molar concentrations by assuming a model of a spherical chaperoning complex. In the model, alpha-crystallin is the central core and alpha-lactalbumin molecules occupy a ring surrounding the core. The kinetics of chaperoning was studied by proposing a simple scheme with four rate constants. The reversible reaction of the formation of the chaperoning complex is characterized by rate constants k(1) and k(2). The rate constants k(3) and k(4) govern the irreversible aggregation of lactalbumin: the former from the free monomeric lactalbumin pool and the latter describing the aggregation of the denatured lactalbumin released from the chaperoning complex. The rate constants, k(3) and k(4) are four magnitudes larger than k(1) and k(2). The equilibrium constant of chaperoning complex formation lies in favor of the reactants. k(4) is somewhat faster than k(3) and it is three times faster than k(s) governing the self-aggregation of lactalbumin in the absence of alpha-crystallin. PMID:12063118

Bettelheim, Frederick A

2002-06-18

436

On the formation of active region prominences (H alpha filaments)  

NASA Technical Reports Server (NTRS)

Analysis of sequential H alpha images of active region prominence formation suggests that simple large-scale photospheric mass-motions may play a key role in the formation of these long, thin, H alpha filaments.

Rompolt, Bogdan; Bogdan, Thomas

1986-01-01

437

An assay for intermolecular exchange of alpha crystallin  

NASA Technical Reports Server (NTRS)

An affinity column of alpha crystallin linked to cyanogen bromide-activated Sepharose was developed to study the exchange of alpha subunits. Alpha crystallin bound to the Sepharose-alpha complex was dissociated with 8 mol/l urea, followed by quantitation using high-performance reverse-phase liquid chromatography. The time course of binding at 37 degrees C showed a hyperbolic binding pattern reaching equilibrium between 6-18 hr. Under these conditions, binding of beta and gamma crystallins to the same matrix was less than 10% of the alpha values, as was binding of alpha to glycine-coupled Sepharose. This assay was used to demonstrate changes in the subunit exchange of alpha crystallins present in high molecular weight versus lower molecular weight aggregates of the human lens. These results show that this binding procedure was a specific reproducible assay that might be used to study intermolecular interactions of the alpha crystallins.

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

1992-01-01

438

Study of alpha background in a dark matter detector  

E-print Network

Alpha background, specifically from radon and its progeny in the uranium and thorium chains, has been a major issue in dark matter detectors. This work focuses on alpha background presence in the DMTPC experiment by examining ...

Yegoryan, Hayk

2010-01-01

439

Who Is at Risk for Alpha-1 Antitrypsin Deficiency?  

MedlinePLUS

... on Twitter. Who Is at Risk for Alpha-1 Antitrypsin Deficiency? Alpha-1 antitrypsin (AAT) deficiency occurs in all ethnic groups. ... it doesn't mean that you'll develop one of the diseases related to the condition. Some ...

440

Antibody-mediated reduction of .alpha.-ketoamides  

DOEpatents

Monoclonal antibodies raised against a 4-nitrophenyl phosphonate hapten catalyze the stereospecific reduction of an .alpha.-ketoamide to the corresponding .alpha.-hydroxyamide in the presence of an appropriate reducing agent.

Schultz, Peter G. (Oakland, CA); Gallop, Mark A. (East Palo Alto, CA)

1998-01-01

441

Chromospheric Lyman-alpha Core Emission of Altair.  

National Technical Information Service (NTIS)

Following the first claim for the detection of the Lyman alpha emission from Altair, SWP IUE (Short Wavelength Prime International Ultraviolet Explorer) spectra had confirmed the existence of that chromospheric feature. To obtain the stellar Ly alpha core...

R. Freireferrero, S. Catalano, P. Goutebroze, E. Marilli

1990-01-01

442

Structural and electrochemical studies of alpha manganese dioxide ({alpha}-MnO{sub 2})  

SciTech Connect

The structural and electrochemical properties of alpha-MnO[sub 2], prepared by acid digestion of Mn[sub 2]O[sub 3], and its lithiated derivatives xLi[sub 2] O . MnO[sub 2] (where x is greater than or equal to zero and less than or equal to 0.25) have been investigated as insertion compounds in the search for new and viable cathode materials for rechargeable 3-V batteries. The alpha-MnO[sub 2] product fabricated by this technique contains water within the large (2x2) channels of the structure; the water can be removed from the alpha-MnO[sub 2] framework without degradation of the structure, and then at least partially replaced by Li[sub 2]O. The lithia-doped alpha-MnO[sub 2] electrodes, described generically as xLi[sub 2]O . Mno[sub 2], stabilize the structure and provide higher capacities on cycling than the parent material. The structures of these alpha- MnO[sub 2]-type electrode materials are described. and electrochemical data are presented for both liquid electrolyte and polymer electrolyte Li/alpha-MnO[sub 2] and Li/xLi[sub 2]O . MnO[sub 2] cells.

Johnson, C.S.; Dees, D.W.; Mansuetto, M.F.; Thackeray, M.M.; Vissers, D.R.; Argyriou, D.; Loong, C.-K. [Argonne National Lab., IL (United States); Christensen, L. [Minnesota Mining and Mfg. Co., St. Paul, MN (United States)

1996-08-01

443

Heat transfer coefficients of shell and coiled tube heat exchangers  

SciTech Connect

In the present study, the heat transfer coefficients of shell and helically coiled tube heat exchangers were investigated experimentally. Three heat exchangers with different coil pitches were selected as test section for both parallel-flow and counter-flow configurations. All the required parameters like inlet and outlet temperatures of tube-side and shell-side fluids, flow rate of fluids, etc. were measured using appropriate instruments. Totally, 75 test runs were performed from which the tube-side and shell-side heat transfer coefficients were calculated. Empirical correlations were proposed for shell-side and tube-side. The calculated heat transfer coefficients of tube-side were also compared to the existing correlations for other boundary conditions and a reasonable agreement was observed. (author)

Salimpour, M.R. [Department of Mechanical Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran)

2009-01-15

444

Calculations of accommodation coefficients for diatomic molecular gases.  

PubMed

A theoretical study of energy and momentum accommodation coefficients and reduced force coefficients for molecular gases exchanging energy with surfaces has been carried out. The theoretical model uses classical mechanics for describing translational and rotational motions while internal molecular vibrational modes are treated quantum mechanically. Calculations for diatomic molecular gases are compared with recent measurements using hypersonic beams of N2 incident on SiO2 layers deposited on Kapton substrates. The theory gives good qualitative predictions of the behavior of the various accommodation coefficients as functions of the available experimentally controllable parameters such as incident translational energy, incident beam angle, molecular and surface masses, and surface temperature. Quantitative comparisons with measurements for energy and normal momentum accommodation indicate that these experiments can be used to obtain basic physical information about the molecule-surface interaction such as the physisorption potential well depth and the extent of surface roughness. PMID:16605510

Ambaye, Hailemariam; Manson, J R

2006-03-01

445

[A new CBCT denoising method based on coefficient classification].  

PubMed

Denoising is an important issue for medical image processing. In this paper, a fast CBCT denoising method was proposed: CBCT images were transformed into wavelet domain with dyadic wavelet transform. According to the inter-scale relationship of wavelet coefficient magnitude sum in cone of influence (COI), wavelet coefficients were classified into two categories, then different types of coefficient were denoised by different wiener filtering based on direction window at all levels, and a new noise variation estimating method more suitable for CBCT images was proposed. Experimental results of a test image and a clinical CBCT image show that this algorithm is superior to the conventional method for wavelet shrinkage denoising. This algorithm can suppress noise in CBCT images effectively and keep up the important structure details for diagnosis, thus providing a new approach for real-time denoising clinical CBCT images. PMID:20649039

Sun, Qian; Yin, Yong; Lu, Jie; Peng, Yuhuat

2010-06-01

446

Townsend coefficients for electron scattering over dielectric surfaces  

NASA Technical Reports Server (NTRS)

A method for describing the probability of initiating flashover discharges across dielectric surfaces is presented in which a transport coefficient for electron multiplication similar to the Townsend coefficient used for gas discharges is defined. The coefficient is a function of the scaling parameter (charge released from the cathode)/(cathode-anode separation) and is also a measure of the growth of the sheath on the dielectric surface resulting from electron scattering. Results are discussed as to when the source of seed electrons does not necessarily depend upon field emission at the cathode-vacuum-dielectric triple point. For these conditions, there is a different functional dependence of flashover probability on voltage and geometry than when field emission provides the seed electrons. As a result, criteria previously used to predict flashover discharges may not apply.

Peck, Timothy L.; Kushner, Mark J.

1988-01-01

447

NASA Glenn Coefficients for Calculating Thermodynamic Properties of Individual Species  

NASA Technical Reports Server (NTRS)

This report documents the library of thermodynamic data used with the NASA Glenn computer program CEA (Chemical Equilibrium with Applications). This library, containing data for over 2000 solid, liquid, and gaseous chemical species for temperatures ranging from 200 to 20,000 K, is available for use with other computer codes as well. The data are expressed as least-squares coefficients to a seven-term functional form for C((sup o)(sub p)) (T) / R with integration constants for H (sup o) (T) / RT and S(sup o) (T) / R. The NASA Glenn computer program PAC (Properties and Coefficients) was used to calculate thermodynamic functions and to generate the least-squares coefficients. PAC input was taken from a variety of sources. A complete listing of the database is given along with a summary of thermodynamic properties at 0 and 298.15 K.

McBride, Bonnie J.; Zehe, Michael J.; Gordon, Sanford

2002-01-01

448

Heart Rate Variability Analysis Using Threshold of Wavelet Package Coefficients  

E-print Network

In this paper, a new efficient feature extraction method based on the adaptive threshold of wavelet package coefficients is presented. This paper especially deals with the assessment of autonomic nervous system using the background variation of the signal Heart Rate Variability HRV extracted from the wavelet package coefficients. The application of a wavelet package transform allows us to obtain a time-frequency representation of the signal, which provides better insight in the frequency distribution of the signal with time. A 6 level decomposition of HRV was achieved with db4 as mother wavelet, and the above two bands LF and HF were combined in 12 specialized frequencies sub-bands obtained in wavelet package transform. Features extracted from these coefficients can efficiently represent the characteristics of the original signal. ANOVA statistical test is used for the evaluation of proposed algorithm.

Kheder, G; Massoued, M Ben; Samet, M

2009-01-01

449

Single-particle tracking: the distribution of diffusion coefficients.  

PubMed Central

In single-particle tracking experiments, the diffusion coefficient D may be measured from the trajectory of an individual particle in the cell membrane. The statistical distribution of single-trajectory diffusion coefficients is examined by Monte Carlo calculations. The width of this distribution may be useful as a measure of the heterogeneity of the membrane and as a test of models of hindered diffusion in the membrane. For some models, the distribution of the short-range diffusion coefficient is much narrower than the observed distribution for proteins diffusing in cell membranes. To aid in the analysis of single-particle tracking measurements, the distribution of D is examined for various definitions of D and for various trajectory lengths. PMID:9083678

Saxton, M J

1997-01-01

450

Bounds on OPE Coefficients in 4D Conformal Field Theories  

E-print Network

We numerically study the crossing symmetry constraints in 4D CFTs, using previously introduced algorithms based on semidefinite programming. We study bounds on OPE coefficients of tensor operators as a function of their scaling dimension and extend previous studies of bounds on OPE coefficients of conserved vector currents to the product groups SO(N)xSO(M). We also analyze the bounds on the OPE coefficients of the conserved vector currents associated with the groups SO(N), SU(N) and SO(N)xSO(M) under the assumption that in the singlet channel no scalar operator has dimension less than four, namely that the CFT has no relevant deformations. This is motivated by applications in the context of composite Higgs models, where the strongly coupled sector is assumed to be a spontaneously broken CFT with a global symmetry.

Caracciolo, Francesco; von Harling, Benedict; Serone, Marco

2014-01-01

451

Broadband computation of the scattering coefficients of infinite arbitrary cylinders.  

PubMed

We employ a time-domain method to compute the near field on a contour enclosing infinitely long cylinders of arbitrary cross section and constitution. We therefore recover the cylindrical Hankel coefficients of the expansion of the field outside the circumscribed circle of the structure. The recovered coefficients enable the wideband analysis of complex systems, e.g., the determination of the radar cross section becomes straightforward. The prescription for constructing such a numerical tool is provided in great detail. The method is validated by computing the scattering coefficients for a homogeneous circular cylinder illuminated by a plane wave, a problem for which an analytical solution exists. Finally, some radiation properties of an optical antenna are examined by employing the proposed technique. PMID:23005567

Blanchard, Cédric; Guizal, Brahim; Felbacq, Didier

2012-07-01

452

Generic transport coefficients of a confined electrolyte solution  

E-print Network

Physical parameters characterising electrokinetic transport in a confined electrolyte solution are reconstructed from the generic transport coefficients obtained within the classical non-equilibrium statistical thermodynamic framework. The electro-osmotic flow, the diffusio-osmotic flow, the osmotic current, as well as the pressure-driven Poiseuille-type flow, the electric conduction, and the ion diffusion, are described by this set of transport coefficients. The reconstruction is demonstrated for an aqueous NaCl solution between two parallel charged surfaces with a nanoscale gap, by using the molecular dynamic (MD) simulations. A Green-Kubo approach is employed to evaluate the transport coefficients in the linear-response regime, and the fluxes induced by the pressure, electric, and chemical potential fields are compared with the results of non-equilibrium MD simulations. Anomalous reversal of diffusio-osmotic current, as well as that of electro-osmotic flow, at high surface charge density and high added-sal...

Yoshida, Hiroaki; Kinjo, Tomoyuki; Washizu, Hitoshi; Barrat, Jean-Louis

2014-01-01

453

Prediction of absorption coefficients by pulsed laser induced photoacoustic measurements.  

PubMed

In the current study, a pulsed laser induced photoacoustic spectroscopy setup was designed and developed, aiming its application in clinical diagnostics. The setup was optimized with carbon black samples in water and with various tryptophan concentrations at 281nm excitations. The sensitivity of the setup was estimated by determining minimum detectable concentration of tryptophan in water at the same excitation, and was found to be 0.035mM. The photoacoustic experiments were also performed with various tryptophan concentrations at 281nm excitation for predicting optical absorption coefficients in them and for comparing the outcomes with the spectrophotometrically-determined absorption coefficients for the same samples. Absorption coefficients for a few serum samples, obtained from some healthy female volunteers, were also determined through photoacoustic and spectrophotometric measurements at the same excitations, which showed good agreement between them, indicating its clinical implications. PMID:24632160

Priya, Mallika; Satish Rao, B S; Ray, Satadru; Mahato, K K

2014-06-01

454

Triplet extinction coefficients of some laser dyes. II  

SciTech Connect

We measured the triplet extinction coefficients over the laser action spectral region of DODC, DMC, Sulforhodamine B, Rhodamine 575, Coumarin 523, Coumarin 521, Coumarin 504, Coumarin 498, Coumarin 490, LD466, bis-MSB, and BBO. We employed the different lines from an argon and a krypton ion cw laser for excitation. McClure's method was again employed to measure the triplet extinction coefficients. We provide a simplified derivation of McClure's equation. The triplet extinction coefficient of Rhodamine 575 was also measured by using the depletion method and improving it by reconstructing for true triplet-triplet (T-T) absorption. The ET value obtained is in good agreement with the one obtained by McClure's method.

Pavlopoulos, T.G.; Golich, D.J.

1990-01-01

455

Coupling coefficients for tensor product representations of quantum SU(2)  

NASA Astrophysics Data System (ADS)

We study tensor products of infinite dimensional irreducible *-representations (not corepresentations) of the SU(2) quantum group. We obtain (generalized) eigenvectors of certain self-adjoint elements using spectral analysis of Jacobi operators associated to well-known q-hypergeometric orthogonal polynomials. We also compute coupling coefficients between different eigenvectors corresponding to the same eigenvalue. Since the continuous spectrum has multiplicity two, the corresponding coupling coefficients can be considered as 2 × 2-matrix-valued orthogonal functions. We compute explicitly the matrix elements of these functions. The coupling coefficients can be considered as q-analogs of Bessel functions. As a results we obtain several q-integral identities involving q-hypergeometric orthogonal polynomials and q-Bessel-type functions.

Groenevelt, Wolter

2014-10-01

456

Determination of stream reaeration coefficients by use of tracers  

USGS Publications Warehouse

Stream reaeration is the physical absorption of oxygen from the atmosphere by a flowing stream. This is the primary process by which a stream replenishes the oxygen consumed in the biodegradation of organic wastes. Prior to 1965, reaeration rate coefficients could be estimated only by indirect methods. In 1965, a direct method of measuring stream reaeration coefficients was developed in which a radioactive tracer gas was injected into a stream--the tracer gas being desorbed from the stream inversely to how oxygen would be absorbed. The technique has since been modified by substituting hydrocarbon gases for the radioactive tracer gas. The slug-injection and constant-rate injection methods of performing gas tracer desorption measurements are described. Emphasis is on the use of rhodamine WT dye as a relatively conservative tracer and propane as the nonconservative gas tracer, on planning field tests, methods of injection, sampling and analysis, and computational techniques to compute desorption and reaeration coefficients. (Author 's abstract)

Kilpatrick, F. A.; Rathbun, R. E.; Yotsukura, Nobuhiro; Parker, G. W.; DeLong, L. L.

1987-01-01

457

Negative normal restitution coefficient found in simulation of nanocluster collisions.  

PubMed

The oblique impacts of nanoclusters are studied theoretically and by means of molecular dynamics. In simulations we explore two models--Lennard-Jones clusters and particles with covalently bonded atoms. In contrast with the case of macroscopic bodies, the standard definition of the normal restitution coefficient yields for this coefficient negative values for oblique collisions of nanoclusters. We explain this effect and propose a proper definition of the restitution coefficient which is always positive. We develop a theory of an oblique impact based on a continuum model of particles. A surprisingly good agreement between the macroscopic theory and simulations leads to the conclusion that macroscopic concepts of elasticity, bulk viscosity, and surface tension remain valid for nanoparticles of a few hundred atoms. PMID:21231505

Saitoh, Kuniyasu; Bodrova, Anna; Hayakawa, Hisao; Brilliantov, Nikolai V

2010-12-01

458

Reliability of the ALPHA health-related fitness test battery in adolescents with Down syndrome.  

PubMed

The Assessing Levels of Physical Activity (ALPHA) health-related fitness test battery is a set of reliable, valid, and feasible tests to assess health-related physical fitness in children and in adolescents. The aim of this study was to examine the reliability of this battery in adolescents with Down syndrome (DS). The extended ALPHA health-related fitness test battery was performed twice within 1 month in 17 apparently healthy adolescents, aged 12-18 years, with DS who had an intelligence quotient ? 35. Intraclass correlation coefficient (ICC) was used to determinate test-retest reliability, and nonparametric Wilcoxon signed rank test was used to compare mean differences between measurements. With the exception of subscapular skinfold test, which obtained a moderate agreement (ICC = 0.64), all tests had a very high reliability: the 20-m shuttle-run test (ICC = 0.86), the right handgrip strength test (ICC = 0.86), the left handgrip strength test (ICC = 0.86), the standing broad jump test (ICC = 0.85), body mass index (ICC = 0.95), waist circumference (ICC = 0.98), triceps skinfold (ICC = 0.85), and the 4 × 10-m shuttle-run test (ICC = 0.92). There were no significant differences (all p > 0.05) in any of the tests. The ALPHA health-related fitness battery is reliable for measuring health-related components of fitness in adolescents with DS. PMID:23442277

Tejero-Gonzalez, Carlos M; Martinez-Gomez, David; Bayon-Serna, Jorge; Izquierdo-Gomez, Rocio; Castro-Piñero, Jose; Veiga, Oscar L

2013-11-01

459

Possible stimulation of nuclear alpha decay by superfluid helium.  

PubMed

It is suggested that superfluid helium (condensate of (4)He atoms) may stimulate nuclear alpha decay in a situation when an alpha emitter moves through superfluid helium with fine-tuned velocity, so that the backward-emitted alpha particle is at rest in the laboratory frame. It is shown that the probability of stimulated alpha decay in this case may be sizable enough to be detected. PMID:19792793

Barabanov, A L

2009-08-28

460

Prevalence of alphas1-casein genotypes in American dairy goats.  

PubMed

Widespread genotyping of US dairy goat breeds for casein variants has not been reported, even though the genetic data could be of use in selective breeding programs. For instance, variability in the content of protein and solids in goat milk is attributed to allelic differences in the goat alpha(s1)-casein gene. Concentrations of alpha(s1)-casein in goat milk are positively correlated with milk components and coagulation properties. The alleles A and B are designated as strong alleles, resulting in the greatest amount of alpha(s1)-casein in goat milk, whereas the E allele produces intermediate amounts and the weak allele F produces the least concentrations of alpha(s1)-casein in goat milk. Here we report on one of the first surveys of the distribution of alpha(s1)-casein genotypes in US dairy goats. The population surveyed, consisting of a total of 257 American dairy goats representing 7 main dairy breeds, contained a greater predominance of the weaker alleles, E and F, than the strong alleles, A and B. Allele distribution was related to breed, with Toggenburg, Alpine, Saanen, and Oberhasli containing the most E and F alleles and LaMancha, Nubian, and Nigerian Dwarf the fewest. Quantification of alpha(s1)-casein production by 2-dimensional gel electrophoresis demonstrated that F/F animals had the least amount of alpha(s1)-casein protein in their milk compared with all other genotypes. The results indicate that genetic improvement of dairy goats in the United States could be achieved if an alpha(s1)-casein breeding scheme were adopted. PMID:19648483

Maga, E A; Daftari, P; Kültz, D; Penedo, M C T

2009-11-01

461

Possible stimulation of nuclear alpha-decay by superfluid helium  

E-print Network

It is suggested that superfluid helium (condensate of 4-He atoms) may stimulate nuclear alpha-decay in a situation when an alpha-emitter moves through superfluid helium with fine-tuned velocity, so that the backward-emitted alpha-particle is at rest in the laboratory frame. It is shown that the probability of stimulated alpha-decay in this case may be sizable enough to be detected.

A. L. Barabanov

2009-02-26

462

The Capture of Electrons by Swiftly Moving Alpha-Particles  

Microsoft Academic Search

Relative velocities of an alpha particle and an electron which are favorable for the capture of the electron.-A stream of electrons from a thermionic source is superposed on a beam of alpha-particles from polonium. To determine the number of captures, the alpha-particle beam is subjected to a magnetic field and the number of deflected alpha-particles counted by the scintillation method.

Bergen Davis; A. H. Barnes

1929-01-01

463

A rapid approach to 11 alpha-hemisuccinylprogesterone synthesis.  

PubMed

The synthetic hapten 11 alpha-hemisuccinylprogesterone (11 alpha-hemisuccinyl-pregn-4-ene-3,20-dione), when linked to the appropriate macromolecular carrier, has been used successfully as a solid-phase antigen for progesterone detection in immunoassay. In this study the synthesis of 11 alpha-hemisuccinylprogesterone from 11 alpha-hydroxyprogesterone has been improved by using 4-dimethylaminopyridine (DMAP in refluxing dioxane, a highly nucleophilic polar solvent. PMID:3254631

Mitchell, M O

1988-01-01

464

The determination of transpiration efficiency coefficient for common bean  

NASA Astrophysics Data System (ADS)

A number of studies have been conducted to determine species specific transpiration efficiency coefficient. Although the value is available for some C3 legumes, no value has been determined for common beans within the semi-arid tropics. The coefficient is useful in modelling crop water use as it has been found to be conservative over a range of climates when differences in vapour pressure deficits are accounted for. The objective of the experiment was to determine the transpiration efficiency coefficient for common beans for use in modelling within the semi-arid region of South Africa. Common bean ( Phaseoulus vulgaris L.) was grown on a weighing lysimeter during the 2000/2001 and 2001/2002 seasons. Transpiration was measured on hourly basis using the weighing lysimeter and the data integrated over the growing season to determine the seasonal transpiration for the crop. At the same time hourly measurement of canopy vapour pressure deficit was made using wet and dry bulb resistance thermometers housed in mini-shelters at 200-400 mm height. Wet and dry bulb temperature data was also collected at the nearby standard automatic weather station and used to normalize the transpiration efficiency. Transpiration efficiency for the common bean was 1.33 and 1.93 g kg -1 which when normalized and root adjusted, gave a transpiration efficiency coefficient of 3.02 and 3.51 g kPa kg -1 for the 2000/2001 and 2001/2002 seasons respectively. A mean transpiration efficiency coefficient of 3.26 ± 0.25 g kPa kg -1 was adopted for the two seasons. This value is fairly consistent with those obtained for other C3 legumes species, confirming the conservativeness of the coefficient and therefore its usefulness as modelling parameter.

Ogindo, H. O.; Walker, S.

465

Application of distribution coefficients to radiological assessment models  

SciTech Connect

A field and laboratory investigation of the transport of fallout radionuclides in natural, organic rich ecosystems has been initiated. Mountain-top peat bogs in Pennsylvania, New York and Virginia were sampled by coring, dated by Pb-210 methods and measured for bomb-produced Sr-90, Pu-239, 240, and Cs-137; laboratory measurements of the distribution coefficients for Cs-137, Sr-85, Ru-106, Am-241, and Co-57