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2012

Wayne State University

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Articles 1 - 30 of 132

Full-Text Articles in Physical Sciences and Mathematics

Selection Of Mixed Sampling Plan With Qss-1(N; CN, CT) Plan As Attribute Plan Indexed Through Mapd And Lql, R. Sampath Kumar, M. Indra, R. Radhakrishnan Nov 2012

Selection Of Mixed Sampling Plan With Qss-1(N; CN, CT) Plan As Attribute Plan Indexed Through Mapd And Lql, R. Sampath Kumar, M. Indra, R. Radhakrishnan

Journal of Modern Applied Statistical Methods

A procedure for the construction and selection of the mixed sampling plan using MAPD as a quality standard with the QSS-1 (n; cN, cT) plan as an attribute plan is presented. The plans indexed through MAPD and LQL are constructed and compared for efficiency. Tables are provided for selection of an appropriate sampling plan.

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Regression Split By Levels Of The Dependent Variable, Stan Lipovetsky Nov 2012

Regression Split By Levels Of The Dependent Variable, Stan Lipovetsky

Journal of Modern Applied Statistical Methods

Multiple regression coefficients split by the levels of the dependent variable are examined. The decomposition of the coefficients can be defined by points on the ordinal scale or by levels in the numerical response using the Gifi system of binary variables. This approach permits consideration of specific values of the coefficients at each layer of the response variable. Numerical results illustrate how to identify levels of interpretable regression coefficients.

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Class(Es) Of Factor-Type Estimator(S) In Presence Of Measurement Error, Diwakar Shukla, Sharad Pathak, Narendra Singh Thakur Nov 2012

Class(Es) Of Factor-Type Estimator(S) In Presence Of Measurement Error, Diwakar Shukla, Sharad Pathak, Narendra Singh Thakur

Journal of Modern Applied Statistical Methods

When data is collected via sample survey it is assumed whatever is reported by a respondent is correct. However, given the issues of prestige bias, personal respect and honor, respondents’ self-reported data often produces over- or under- estimated values as opposed to true values regarding the variables under question. This causes measurement error to be present in sample values. This article considers the factortype estimator as an estimation tool and examines its performance under a measurement error model. Expressions of optimization are derived and theoretical results are supported by numerical examples.

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A Graphical Examination Of Variable Deletion Within The Mewma Statistic, Jay R. Schaffer, Shawn Vandenhul Nov 2012

A Graphical Examination Of Variable Deletion Within The Mewma Statistic, Jay R. Schaffer, Shawn Vandenhul

Journal of Modern Applied Statistical Methods

A general procedure for identifying the variable(s) that contribute(s) to the signal of the multivariate extension of the exponentially weighted moving average (MEWMA) chart is presented. The procedure systematically removes one or two variables from the MEWMA statistic calculations. Percentages are calculated for correctly identifying various shifts.

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Examining Multiple Comparison Procedures According To Error Rate, Power Type And False Discovery Rate, Guven Ozkaya, Ilker Ercan Nov 2012

Examining Multiple Comparison Procedures According To Error Rate, Power Type And False Discovery Rate, Guven Ozkaya, Ilker Ercan

Journal of Modern Applied Statistical Methods

Examining pairwise differences between means is a common practice of applied researchers, and the selection of an appropriate multiple comparison procedure (MCP) is important for analyzing pairwise comparisons. This study examines the performance of MCPs under the assumption of homogeneity of variances for various numbers of groups with equal and unequal sample sizes via a simulation study. MCPs are compared according to type I error rate, power type and false discovery rate (FDR). Results show that the LSD and Duncan procedures have high error rates and Scheffe’s procedure has low power; no remarkable differences between the other procedures considered were …

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Modified Edf Goodness Of Fit Tests For Logistic Distribution Under Srs And Rss, S. A. Al-Subh, M. T. Alodat, Kamaruzaman Ibrahim, Abdul Aziz Jemain Nov 2012

Modified Edf Goodness Of Fit Tests For Logistic Distribution Under Srs And Rss, S. A. Al-Subh, M. T. Alodat, Kamaruzaman Ibrahim, Abdul Aziz Jemain

Journal of Modern Applied Statistical Methods

Modified forms of goodness of fit tests are presented for the logistic distribution using statistics based on the empirical distribution function (EDF). A method to improve the power of the modified EDF goodness of fit tests is introduced based on Ranked Set sampling (RSS). Data are collected via the Ranked Set Sampling (RSS) technique (McIntyre, 1952). Critical values for the logistic distribution with unknown parameters are provided and the powers of the tests are given for a number of alternative distributions. A simulation study is presented to illustrate the power of the new method.

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On Some Negative Integer Moments Of Quasi-Negative-Binomial Distribution, Anwar Hassan, Sheikh Bilal Nov 2012

On Some Negative Integer Moments Of Quasi-Negative-Binomial Distribution, Anwar Hassan, Sheikh Bilal

Journal of Modern Applied Statistical Methods

Negative integer moments of the quasi-negative-binomial distribution (QNBD) are investigated. This distribution includes recurrence relations which are helpful in the solution of many applied statistical problems, particularly in life testing and survey sampling, where ratio estimators are useful. Results study show the negative-binomial distribution when the parameter θ2 is zero and also indicate the mean of the QNBD model when its parameters are changed.

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Single Sampling Plans For Variables Indexed By Aql And Aoql With Measurement Error, R. Sankle, J.R. Singh Nov 2012

Single Sampling Plans For Variables Indexed By Aql And Aoql With Measurement Error, R. Sankle, J.R. Singh

Journal of Modern Applied Statistical Methods

Single sampling plans are investigated for variables indexed by acceptable quality level (AQL) and average outgoing quality limit (AOQL) under measurement error. Procedures and tables are provided for selection of single sampling plans for variables for given AQL and AOQL when rejected lots are 100% inspected for replacement of a nonconforming unit. For a particular sampling plan in operation for an observed measurement, a method for determining true operating characteristic (OC) functions and average outgoing quality (AOQ) is described for various error sizes.

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Small-To-Medium Enterprises And Economic Growth: A Comparative Study Of Clustering Techniques, Karim K. Mardaneh Nov 2012

Small-To-Medium Enterprises And Economic Growth: A Comparative Study Of Clustering Techniques, Karim K. Mardaneh

Journal of Modern Applied Statistical Methods

Small-to-medium enterprises (SMEs) in regional (non-metropolitan) areas are considered when economic planning may require large data sets and sophisticated clustering techniques. The economic growth of regional areas was investigated using four clustering algorithms. Empirical analysis demonstrated that the modified global k-means algorithm outperformed other algorithms.

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Exact Logistic Regression For A Matched Pairs Case-Control Design With Polytomous Exposure Variables, Shyam S. Ganguly Nov 2012

Exact Logistic Regression For A Matched Pairs Case-Control Design With Polytomous Exposure Variables, Shyam S. Ganguly

Journal of Modern Applied Statistical Methods

Logistic regression methods are useful in estimating odds ratios under matched pairs case-control designs when the exposure variable of interest is binary or polytomous in nature. Analysis is typically performed using large sample approximation techniques. When conducting the analysis with polytomous exposure variable, situations where the numbers of discordant pairs in the resulting cells are small or the data structure is sparse can be encountered. In such situations, the asymptotic method of analysis is questionable, thus an exact method of analysis may be more suitable. A method is presented that performs exact inference in the case of pair-wise matched case-control …

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Graphical Modeling For High Dimensional Data, Munni Begum, Jay Bagga, C. Ann Blakey Nov 2012

Graphical Modeling For High Dimensional Data, Munni Begum, Jay Bagga, C. Ann Blakey

Journal of Modern Applied Statistical Methods

With advances in science and information technologies, many scientific fields are able to meet the challenges of managing and analyzing high-dimensional data. A so-called large p small n problem arises when the number of experimental units, n, is equal to or smaller than the number of features, p. A methodology based on probability and graph theory, termed graphical models, is applied to study the structure and inference of such high-dimensional data.

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Extreme Value Charts And Analysis Of Means (Anom) Based On The Log Logistic Distribution, B. Srinivasa Rao, J. Pratapa Reddy, G. Sarath Babu Nov 2012

Extreme Value Charts And Analysis Of Means (Anom) Based On The Log Logistic Distribution, B. Srinivasa Rao, J. Pratapa Reddy, G. Sarath Babu

Journal of Modern Applied Statistical Methods

A probability model of a quality characteristic is assumed to follow a log logistic distribution. This article proposes variable control charts, termed extreme value charts, based on the extreme values of each subgroup. The control chart constants depend on the probability model of the extreme order statistics and the size of each subgroup. The analysis of means (ANOM) technique for a skewed population is applied with respect to log logistic distribution. Results are illustrated using examples based on real data.

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Weighted Cook-Johnson Copula And Their Characterizations: Application To Probably Modeling Of The Hot Spring Eruptions, Hakim Bekrizadeh, Gholam Ali Parham, Mohamd Reza Zadkarmi Nov 2012

Weighted Cook-Johnson Copula And Their Characterizations: Application To Probably Modeling Of The Hot Spring Eruptions, Hakim Bekrizadeh, Gholam Ali Parham, Mohamd Reza Zadkarmi

Journal of Modern Applied Statistical Methods

Copulas have emerged as a practical method for multivariate modeling. A limited amount of work has been conducted regarding the application of copula-based modeling in context analysis. This study generalizes the Cook-Johnson copula under the appropriate weighted function and provides examples and the properties of the generalized Cook-Johnson copula. Results show that the generalized Cook-Johnson copula is suitable for probable modeling of hot spring eruption.

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Examining Growth With Statistical Shape Analysis And Comparison Of Growth Models, Deniz Sigirli, Ilker Ercan Nov 2012

Examining Growth With Statistical Shape Analysis And Comparison Of Growth Models, Deniz Sigirli, Ilker Ercan

Journal of Modern Applied Statistical Methods

Growth curves have been widely used in the fields of biology, zoology and medicine for assessing some measurable trait of an organism, such as height, weight, area or volume. In statistical shape analysis, a size measure is obtained using the geometrical information of an object as opposed to linear measurements. The performances of commonly used non-linear growth curves are compared by using centroid size as a size measure in a simulation study. An example is provided on the relationship between centroid size of the cerebellum and disease duration in multiple sclerosis patients.

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Posterior Estimates Of Poisson Distribution Using R Software, Raja Sultan, S.P. Ahmad Nov 2012

Posterior Estimates Of Poisson Distribution Using R Software, Raja Sultan, S.P. Ahmad

Journal of Modern Applied Statistical Methods

The Bayesian estimation of unknown parameter of the Poisson distribution is examined under different priors. The posterior distributions for the unknown parameter of the Poisson distribution are derived using the following priors: uniform, Jeffrey’s, Gamma distribution, Gamma-Chi-square distribution, Gammaexponential distribution and Chi-square-exponential distribution. Numerical and graphical illustrations of the posterior densities of the parameters of interest were conducted using R Software.

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Ferrieri's Index Of Openness Applied To Remittances To Developing Countries, Gaetano Ferrieri Nov 2012

Ferrieri's Index Of Openness Applied To Remittances To Developing Countries, Gaetano Ferrieri

Journal of Modern Applied Statistical Methods

A new methodology to measure international openness and globalization is described. This allows capacity to be effectively combined with size in a number of socio-economic areas, such as trade, migration and foreign investment. The method is applied to remittances to developing countries.

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Multivariate Generalized Poisson Distribution For Interference On Selected Non-Communicable Diseases In Lagos State, Nigeria, Adewara Johnson Ademola, Mbata Ugochuckwu Ahamefula Nov 2012

Multivariate Generalized Poisson Distribution For Interference On Selected Non-Communicable Diseases In Lagos State, Nigeria, Adewara Johnson Ademola, Mbata Ugochuckwu Ahamefula

Journal of Modern Applied Statistical Methods

Multivariate Generalized Poisson Distribution (MGPD) models are applied to make inferences regarding non-communicable diseases, diabetes, hypertension, stroke and ulcer in Lagos State, Nigeria. The generalized Poisson distribution is employed due to its usefulness in modeling count data in the presence of either over- or under- dispersion. Results show that the correlation between ulcer and stroke is not significant. Other pairwise comparisons of diseases are significant, thus implying that a patient who suffers from diabetes or stroke has a high propensity to also be hypertensive.

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The Disk-Wind-Jet Connection In The Black Hole H 1743-322, J. M. Miller, J. Raymond, A. C. Fabian, C. S. Reynolds, A. L. King, T. R. Kallman, E. M. Cackett, M. Van Der Klis, D. T. H. Steeghs Nov 2012

The Disk-Wind-Jet Connection In The Black Hole H 1743-322, J. M. Miller, J. Raymond, A. C. Fabian, C. S. Reynolds, A. L. King, T. R. Kallman, E. M. Cackett, M. Van Der Klis, D. T. H. Steeghs

Physics and Astronomy Faculty Research Publications

X-ray disk winds are detected in spectrally soft, disk-dominated phases of stellar-mass black hole outbursts. In contrast, compact, steady, relativistic jets are detected in spectrally hard states that are dominated by non-thermal X-ray emission. Although these distinctive outflows appear to be almost mutually exclusive, it is possible that a disk wind persists in hard states but cannot be detected via X-ray absorption lines owing to very high ionization. Here, we present an analysis of a deep, 60 ks Chandra/HETGS observation of the black hole candidate H 1743-322 in the low/hard state. The spectrum shows no evidence of a disk wind, …

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Comparing Two Independent Groups Via A Quantile Generalization Of The Wilcoxon-Mann-Whitney Test, Rand R. Wilcox Nov 2012

Comparing Two Independent Groups Via A Quantile Generalization Of The Wilcoxon-Mann-Whitney Test, Rand R. Wilcox

Journal of Modern Applied Statistical Methods

The Wilcoxon-Mann-Whitney test, as well as modern improvements, are based in part on an estimate of p = P(D < 0), where D = X−Y and X and Y are independent random variables; a common goal is to test H0: p = 0.5. This corresponds to testing H0: ξ0.5, where ξ0.5 is the 0.5 quantile of the distribution of D. If the distributions associated with X and Y do not differ, then D has a symmetric distribution about zero. In particular, ξq + ξ1-q = 0 for any q ≤ 0.5, where ξq is the qth quantile. Methods aimed at testing H0: p = 0.5 are generalized by …

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Testing The Population Coefficient Of Variation, Shipra Banik, B. M. Golam Kibria, Dinesh Sharma Nov 2012

Testing The Population Coefficient Of Variation, Shipra Banik, B. M. Golam Kibria, Dinesh Sharma

Journal of Modern Applied Statistical Methods

The coefficient of variation (CV), which is used in many scientific areas, measures the variability of a population relative to its mean and standard deviation. Several methods exist for testing the population CV. This article compares a proposed bootstrap method to existing methods. A simulation study was conducted under both symmetric and skewed distributions to compare the performance of test statistics with respect to empirical size and power. Results indicate that some of the proposed methods are useful and can be recommended to practitioners.

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On Some Properties And Estimation Of Size-Biased Polya-Eggenberger Distribution, Anwar Hassan, Sheikh Bilal, Imtiyaz Ahmad Shah Nov 2012

On Some Properties And Estimation Of Size-Biased Polya-Eggenberger Distribution, Anwar Hassan, Sheikh Bilal, Imtiyaz Ahmad Shah

Journal of Modern Applied Statistical Methods

A size-biased version of Polya-Eggenberger distribution is introduced explicitly and by a mixture model. The proposed distribution is unimodal with positive integer moments. The recurrence relation between moments (about the origin) of the proposed distribution is established and its relationship with other distributions is discussed. Different estimation techniques are proposed to estimate the parameters of the distribution.

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An Extension Of Cochran-Orcutt Procedure For Generalized Linear Regression Models With Periodically Correlated Errors, Abdullah A. Smadi, Nour H. Abu-Afouna Nov 2012

An Extension Of Cochran-Orcutt Procedure For Generalized Linear Regression Models With Periodically Correlated Errors, Abdullah A. Smadi, Nour H. Abu-Afouna

Journal of Modern Applied Statistical Methods

An important assumption of ordinary regression models is independence among errors. This research considers the case of periodically correlated errors following the periodic AR model of order 1 (PAR(1)). The remedial measure for correlated errors in regression known as the Cochran-Orcutt procedure is generalized to the case of periodically correlated errors. The motivation for making such generalizations is that the response data may inhibit some seasonality, which may not be captured by the traditional AR(1) autoregressive model. The proposed procedure is described and the bias and MSE of the resulting intercept and slope parameter estimates of the simple LR model …

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Bayesian Estimation Of Erlang Distribution Under Different Generalized Truncated Distributions As Priors, Adil H. Khan, T.R. Jan Nov 2012

Bayesian Estimation Of Erlang Distribution Under Different Generalized Truncated Distributions As Priors, Adil H. Khan, T.R. Jan

Journal of Modern Applied Statistical Methods

Various generalized truncated distributions are considered as independent informative priors for estimating shape and scale parameters of the Erlang distribution. In addition, various special cases are also discussed.

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A Proposed Ridge Parameter To Improve The Least Square Estimator, Ghadban Khalaf Nov 2012

A Proposed Ridge Parameter To Improve The Least Square Estimator, Ghadban Khalaf

Journal of Modern Applied Statistical Methods

Ridge regression, a form of biased linear estimation, is a more appropriate technique than ordinary least squares (OLS) estimation in the case of highly intercorrelated explanatory variables in the linear regression model Y = β + u. Two proposed ridge regression parameters from the mean square error (MSE) perspective are evaluated. A simulation study was conducted to demonstrate the performance of the proposed estimators compared to the OLS, HK and HKB estimators. Results show that the suggested estimators outperform the OLS and the other estimators regarding the ridge parameters in all situations examined.

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Intercalibration Studies Of 210Po And 210Pb In Dissolved And Particulate Seawater Samples, Thomas Church, Sylvain Rigaud, Mark Baskaran, Anupam Kumar, Jana Friedrich, Pere Masque, Viena Puigcorbé, Guebuem Kim, Olivier Radakovitch, Gi Hong, Hui Choi, Gillian Stewart Oct 2012

Intercalibration Studies Of 210Po And 210Pb In Dissolved And Particulate Seawater Samples, Thomas Church, Sylvain Rigaud, Mark Baskaran, Anupam Kumar, Jana Friedrich, Pere Masque, Viena Puigcorbé, Guebuem Kim, Olivier Radakovitch, Gi Hong, Hui Choi, Gillian Stewart

Environmental Science and Geology Faculty Research Publications

Documented is an intercalibration (IC) exercise for both 210Po and 210Pb in seawater aliquots distributed between up to eight international laboratories that followed individual protocols. Dissolved and particulate samples were provided by GEOTRACES during two IC cruises at baseline stations in the North Atlantic and North Pacific oceans. Included were surface and/or deep dissolved and particulate samples at each site, plus complete profiles analyzed by the laboratory of the lead author. An unspecified solid phase standard was also distributed with 210Po and 210Pb in secular equilibrium to confirm spike calibrations. The 210Po activities reported n …

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A Four-Year Xmm-Newton/Chandra Monitoring Campaign Of The Galactic Centre: Analysing The X-Ray Transients, N. Degenaar, R. Wijnands, E. M. Cackett, J. Homan, J. J. M. In 'T Zand, E. Kuulkers, T. J. Maccarone, M. Van Der Klis Sep 2012

A Four-Year Xmm-Newton/Chandra Monitoring Campaign Of The Galactic Centre: Analysing The X-Ray Transients, N. Degenaar, R. Wijnands, E. M. Cackett, J. Homan, J. J. M. In 'T Zand, E. Kuulkers, T. J. Maccarone, M. Van Der Klis

Physics and Astronomy Faculty Research Publications

We report on the results of a four-year long X-ray monitoring campaign of the central 1.2 square degrees of our Galaxy, performed with Chandra and XMM-Newton between 2005 and 2008. Our study focuses on the properties of transient X-ray sources that reach 2-10 keV luminosities of LX ≳ 1034 erg s-1 for an assumed distance of 8 kpc. There are 17 known X-ray transients within the field of view of our campaign, eight of which were detected in outburst during our observations: the transient neutron star low-mass X-ray binaries GRS 1741-2853, AX J1745.6-2901, SAX J1747.0-2853, KS 1741-293 …

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On The Role Of The Accretion Disk In Black Hole Disk-Jet Connections, J. M. Miller, G. G. Pooley, A. C. Fabian, M. A. Nowak, R. C. Reis, E. M. Cackett, K. Pottschmidt, J. Wilms Sep 2012

On The Role Of The Accretion Disk In Black Hole Disk-Jet Connections, J. M. Miller, G. G. Pooley, A. C. Fabian, M. A. Nowak, R. C. Reis, E. M. Cackett, K. Pottschmidt, J. Wilms

Physics and Astronomy Faculty Research Publications

Models of jet production in black hole systems suggest that the properties of the accretion disk—such as its mass accretion rate, inner radius, and emergent magnetic field—should drive and modulate the production of relativistic jets. Stellar-mass black holes in the "low/hard" state are an excellent laboratory in which to study disk-jet connections, but few coordinated observations are made using spectrometers that can incisively probe the inner disk. We report on a series of 20 Suzaku observations of Cygnus X-1 made in the jet-producing low/hard state. Contemporaneous radio monitoring was done using the Arcminute MicroKelvin Array radio telescope. Two important and …

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A Comparison Of Broad Iron Emission Lines In Archival Data Of Neutron Star Low-Mass X-Ray Binaries, Edward M. Cackett, Jon M. Miller, Rubens C. Reis, Andrew C. Fabian, Didier Barret Aug 2012

A Comparison Of Broad Iron Emission Lines In Archival Data Of Neutron Star Low-Mass X-Ray Binaries, Edward M. Cackett, Jon M. Miller, Rubens C. Reis, Andrew C. Fabian, Didier Barret

Physics and Astronomy Faculty Research Publications

Relativistic X-ray disklines have been found in multiple neutron star low-mass X-ray binaries, in close analogy with black holes across the mass scale. These lines have tremendous diagnostic power and have been used to constrain stellar radii and magnetic fields, often finding values that are consistent with independent timing techniques. Here, we compare CCD-based data from Suzaku with Fe K line profiles from archival data taken with gas-based spectrometers. In general, we find good consistency between the gas-based line profiles from EXOSAT, BeppoSAX, and RXTE and the CCD data from Suzaku, demonstrating that the broad profiles seen are intrinsic to …

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Genetic Susceptibility To Type 2 Diabetes: A Global Meta-Analysis Studying The Genetic Differences In Tunisian Populations, Rym Berhouma, S. Kouidhi, M. Ammar, H. Abid, T. Baroudi, H. Ennafaa, A. Benammar-Elgaaied Aug 2012

Genetic Susceptibility To Type 2 Diabetes: A Global Meta-Analysis Studying The Genetic Differences In Tunisian Populations, Rym Berhouma, S. Kouidhi, M. Ammar, H. Abid, T. Baroudi, H. Ennafaa, A. Benammar-Elgaaied

Human Biology Open Access Pre-Prints

The present study is the first meta-analysis to evaluate type 2 diabetes (T2D) - associated polymorphisms in cohorts originated from several Tunisian regions. In fact, we evaluated the effect of seven polymorphisms in the following genes; PPARg ( Pro12Ala), TNFα (-308A/G), ENPP1(K121Q), TCF7L2(rs7903146 C/T), MTHFR( C677T), ACE(I/D), CAPN10(3R/2R) on T2D risk, through a meta-analysis combining data of previous studies performed on Tunisian populations originating from the north, centre or south of the country. R statistics version 2.12.1 software was used to estimate the heterogeneity between studies. Pooled ORs were computed by the fixed-effects method of Mantel-Haenszel if no heterogeneity between …

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On The Determination Of The Spin Of The Black Hole In Cyg X-1 From X-Ray Reflection Spectra, A. C. Fabian, D. R. Wilkins, J. M. Miller, R. C. Reis, C. S. Reynolds, E. M. Cackett, M. A. Nowak, G. G. Pooley, K. Pottschmidt, J. S. Sanders, R. R. Ross, J. Wilms Jul 2012

On The Determination Of The Spin Of The Black Hole In Cyg X-1 From X-Ray Reflection Spectra, A. C. Fabian, D. R. Wilkins, J. M. Miller, R. C. Reis, C. S. Reynolds, E. M. Cackett, M. A. Nowak, G. G. Pooley, K. Pottschmidt, J. S. Sanders, R. R. Ross, J. Wilms

Physics and Astronomy Faculty Research Publications

The spin of Cygnus X-1 is measured by fitting reflection models to Suzaku data covering the energy band 0.9-400 keV. The inner radius of the accretion disc is found to lie within 2 gravitational radii (rg=GM/c2), and a value of ? is obtained for the dimensionless black hole spin. This agrees with recent measurements using the continuum fitting method by Gou et al. and of the broad iron line by Duro et al. The disc inclination is measured at ?, which is consistent with the recent optical measurement of the binary system inclination by Orosz et …

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