WorldWideScience

Sample records for adjusted skew information

  1. Metric adjusted skew information

    DEFF Research Database (Denmark)

    Hansen, Frank

    2008-01-01

    establish a connection between the geometrical formulation of quantum statistics as proposed by Chentsov and Morozova and measures of quantum information as introduced by Wigner and Yanase and extended in this article. We show that the set of normalized Morozova-Chentsov functions describing the possible...... quantum statistics is a Bauer simplex and determine its extreme points. We determine a particularly simple skew information, the "¿-skew information," parametrized by a ¿ ¿ (0, 1], and show that the convex cone this family generates coincides with the set of all metric adjusted skew informations.......We extend the concept of Wigner-Yanase-Dyson skew information to something we call "metric adjusted skew information" (of a state with respect to a conserved observable). This "skew information" is intended to be a non-negative quantity bounded by the variance (of an observable in a state...

  2. Metric-adjusted skew information

    DEFF Research Database (Denmark)

    Liang, Cai; Hansen, Frank

    2010-01-01

    We give a truly elementary proof of the convexity of metric-adjusted skew information following an idea of Effros. We extend earlier results of weak forms of superadditivity to general metric-adjusted skew information. Recently, Luo and Zhang introduced the notion of semi-quantum states on a bipa......We give a truly elementary proof of the convexity of metric-adjusted skew information following an idea of Effros. We extend earlier results of weak forms of superadditivity to general metric-adjusted skew information. Recently, Luo and Zhang introduced the notion of semi-quantum states...

  3. An uncertainty relation in terms of generalized metric adjusted skew information and correlation measure

    Science.gov (United States)

    Fan, Ya-Jing; Cao, Huai-Xin; Meng, Hui-Xian; Chen, Liang

    2016-12-01

    The uncertainty principle in quantum mechanics is a fundamental relation with different forms, including Heisenberg's uncertainty relation and Schrödinger's uncertainty relation. In this paper, we prove a Schrödinger-type uncertainty relation in terms of generalized metric adjusted skew information and correlation measure by using operator monotone functions, which reads, U_ρ ^{(g,f)}(A)U_ρ ^{(g,f)}(B)≥ f(0)^2l/k| Corr_ρ ^{s(g,f)}(A,B)| ^2 for some operator monotone functions f and g, all n-dimensional observables A, B and a non-singular density matrix ρ . As applications, we derive some new uncertainty relations for Wigner-Yanase skew information and Wigner-Yanase-Dyson skew information.

  4. An uncertainty relation in terms of generalized metric adjusted skew information and correlation measure

    Science.gov (United States)

    Fan, Ya-Jing; Cao, Huai-Xin; Meng, Hui-Xian; Chen, Liang

    2016-09-01

    The uncertainty principle in quantum mechanics is a fundamental relation with different forms, including Heisenberg's uncertainty relation and Schrödinger's uncertainty relation. In this paper, we prove a Schrödinger-type uncertainty relation in terms of generalized metric adjusted skew information and correlation measure by using operator monotone functions, which reads, U_ρ ^{(g,f)}(A)U_ρ ^{(g,f)}(B)≥ f(0)^2l/k| {Corr}_ρ ^{s(g,f)}(A,B)| ^2 for some operator monotone functions f and g, all n-dimensional observables A, B and a non-singular density matrix ρ . As applications, we derive some new uncertainty relations for Wigner-Yanase skew information and Wigner-Yanase-Dyson skew information.

  5. Inequalities for quantum skew information

    DEFF Research Database (Denmark)

    Audenaert, Koenraad; Cai, Liang; Hansen, Frank

    2008-01-01

    We study quantum information inequalities and show that the basic inequality between the quantum variance and the metric adjusted skew information generates all the multi-operator matrix inequalities or Robertson type determinant inequalities studied by a number of authors. We introduce an order...... relation on the set of functions representing quantum Fisher information that renders the set into a lattice with an involution. This order structure generates new inequalities for the metric adjusted skew informations. In particular, the Wigner-Yanase skew information is the maximal skew information...... with respect to this order structure in the set of Wigner-Yanase-Dyson skew informations....

  6. Quantum Fisher and skew information for Unruh accelerated Dirac qubit

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Subhashish; Alok, Ashutosh Kumar [Indian Institute of Technology Jodhpur, Jodhpur (India); Omkar, S. [Indian Institute of Science Education and Research, Thiruvananthapuram (India)

    2016-08-15

    We develop a Bloch vector representation of the Unruh channel for a Dirac field mode. This is used to provide a unified, analytical treatment of quantum Fisher and skew information for a qubit subjected to the Unruh channel, both in its pure form as well as in the presence of experimentally relevant external noise channels. The time evolution of Fisher and skew information is studied along with the impact of external environment parameters such as temperature and squeezing. The external noises are modelled by both purely dephasing phase damping and the squeezed generalised amplitude damping channels. An interesting interplay between the external reservoir temperature and squeezing on the Fisher and skew information is observed, in particular, for the action of the squeezed generalised amplitude damping channel. It is seen that for some regimes, squeezing can enhance the quantum information against the deteriorating influence of the ambient environment. Similar features are also observed for the analogous study of skew information, highlighting a similar origin of the Fisher and skew information. (orig.)

  7. Uncertainty relations based on skew information with quantum memory

    Science.gov (United States)

    Ma, ZhiHao; Chen, ZhiHua; Fei, Shao-Ming

    2017-01-01

    We present a new uncertainty relation by defining a measure of uncertainty based on skew information. For bipartite systems, we establish uncertainty relations with the existence of a quantum memory. A general relation between quantum correlations and tight bounds of uncertainty has been presented.

  8. Quantifying Correlations via the Wigner-Yanase-Dyson Skew Information

    Science.gov (United States)

    Fan, Yajing; Cao, Huaixin

    2016-09-01

    In this paper, based on a discussion about the Wigner-Yanase-Dyson (WYD) skew information, the measure F a, α ( ρ a b ) for correlations in terms of the WYD skew information is introduced and discussed. The following conclusions are obtained. For a classical-quantum state ρ a b , F a, α ( ρ a b )=0 if and only if ρ a b is a product state; F a, α ( ρ a b ) is locally unitary invariant and convex on the set of states with the fixed marginal ρ a ; F a, α ( ρ a b ) decreases under local random unitary operation on H b ; For a quantum-classical state ρ a b , F a, α ( ρ a b ) decreases under local operation on H b ; Lastly, F a, α ( ρ a b ) is computed for the pure states and the Bell-diagonal states, respectively.

  9. Wigner-Yanase skew information as tests for quantum entanglement

    CERN Document Server

    Chen, Z

    2004-01-01

    A Bell-type inequality is proposed in terms of Wigner-Yanase skew information, which is quadratic and involves only one local spin observable at each site. This inequality presents a hierarchic classification of all states of multipartite quantum systems from separable to fully entangled states, which is more powerful than the one presented by quadratic Bell inequalities from 2-entangled to fully entangled states. In particular, it is proved that the inequality provides an exact test to distinguish entangled from nonentangled pure states of two qubits. Our inequality sheds considerable new light on relationships between quantum entanglement and information theory.

  10. Evolution of cooperation and skew under imperfect information.

    Science.gov (United States)

    Akçay, Erol; Meirowitz, Adam; Ramsay, Kristopher W; Levin, Simon A

    2012-09-11

    The evolution of cooperation in nature and human societies depends crucially on how the benefits from cooperation are divided and whether individuals have complete information about their payoffs. We tackle these questions by adopting a methodology from economics called mechanism design. Focusing on reproductive skew as a case study, we show that full cooperation may not be achievable due to private information over individuals' outside options, regardless of the details of the specific biological or social interaction. Further, we consider how the structure of the interaction can evolve to promote the maximum amount of cooperation in the face of the informational constraints. Our results point to a distinct avenue for investigating how cooperation can evolve when the division of benefits is flexible and individuals have private information.

  11. Skew-symmetric distributions and Fisher information : The double sin of the skew-normal

    NARCIS (Netherlands)

    Hallin, M.; Ley, C.

    2014-01-01

    Hallin and Ley [Bernoulli 18 (2012) 747–763] investigate and fully characterize the Fisher singularity phenomenon in univariate and multivariate families of skew-symmetric distributions. This paper proposes a refined analysis of the (univariate) problem, showing that singularity can be more or less

  12. Conserving Capital by Adjusting Deltas for Gamma in the Presence of Skewness

    Directory of Open Access Journals (Sweden)

    Dilip B. Madan

    2010-12-01

    Full Text Available An argument for adjusting Black Scholes implied call deltas downwards for a gamma exposure in a left skewed market is presented. It is shown that when the objective for the hedge is the conservation of capital ignoring the gamma for the delta position is expensive. The gamma adjustment factor in the static case is just a function of the risk neutral distribution. In the dynamic case one may precompute at the date of trade initiation a matrix of delta levels as a function of the underlying for the life of the trade and subsequently one just has to look up the matrix for the hedge. Also constructed are matrices for the capital reserve, the pro¯t, leverage and rate of return remaining in the trade as a function of the spot at a future date in the life of the trade. The concepts of pro¯t, capital, leverage and return are as described in Carr, Madan and Vicente Alvarez (2010. The dynamic computations constitute an application of the theory of nonlinear expectations as described in Cohen and Elliott (2010.

  13. Shannon Entropy and Mutual Information for Multivariate Skew-Elliptical Distributions

    KAUST Repository

    Arellano-Valle, Reinaldo B.

    2012-02-27

    The entropy and mutual information index are important concepts developed by Shannon in the context of information theory. They have been widely studied in the case of the multivariate normal distribution. We first extend these tools to the full symmetric class of multivariate elliptical distributions and then to the more flexible families of multivariate skew-elliptical distributions. We study in detail the cases of the multivariate skew-normal and skew-t distributions. We implement our findings to the application of the optimal design of an ozone monitoring station network in Santiago de Chile. © 2012 Board of the Foundation of the Scandinavian Journal of Statistics.

  14. Skew information in the XY model with staggered Dzyaloshinskii-Moriya interaction

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Liang, E-mail: lqiu@cumt.edu.cn [School of Physics, China University of Mining and Technology, Xuzhou, Jiangsu 221116 (China); Quan, Dongxiao [State Key Laboratory of Integrated Services Networks, Xidian University, Xi' an, Shaanxi 710071 (China); Pan, Fei; Liu, Zhi [School of Physics, China University of Mining and Technology, Xuzhou, Jiangsu 221116 (China)

    2017-06-01

    We study the performance of the lower bound of skew information in the vicinity of transition point for the anisotropic spin-1/2 XY chain with staggered Dzyaloshinskii-Moriya interaction by use of quantum renormalization-group method. For a fixed value of the Dzyaloshinskii-Moriya interaction, there are two saturated values for the lower bound of skew information corresponding to the spin-fluid and Néel phases, respectively. The scaling exponent of the lower bound of skew information closely relates to the correlation length of the model and the Dzyaloshinskii-Moriya interaction shifts the factorization point. Our results show that the lower bound of skew information can be a good candidate to detect the critical point of XY spin chain with staggered Dzyaloshinskii-Moriya interaction.

  15. Criticality, factorization and Wigner-Yanase skew information in quantum spin chains

    Science.gov (United States)

    Cheng, W. W.; Li, J. X.; Shan, C. J.; Gong, L. Y.; Zhao, S. M.

    2015-07-01

    We apply the Wigner-Yanase skew information approach to analyze criticality and factorization phenomenon in the one-dimensional anisotropy model with uniform coupling interaction and periodic-two one. Based on the exact solutions of the ground states, the Wigner-Yanase skew information between two nearest-neighbor lattices is obtained. For the uniform case, the first-order derivative of the Wigner-Yanase skew information is non-analytically around the critical point. The scaling behavior and the universality are verified numerically. In particular, such skew information can also detect the factorization transition in this model. For the periodic-two case, it is found that there exist more than one phase-transition point in some parameter region due to the competition between periodicity and anisotropy. Furthermore, two kinds of phase transitions, i.e., the Ising and anisotropy transitions, driven by external field and the anisotropy parameter , are investigated carefully by the skew information. Our results state that quantum phase transition driven by the anisotropy parameter can belong to the same universality class as the one driven by external field.

  16. An approximate quantum Cram\\'{e}r--Rao bound based on skew information

    CERN Document Server

    Luati, Alessandra

    2011-01-01

    A closed-form expression for Wigner-Yanase skew information in mixed-state quantum systems is derived. It is shown that limit values of the mixing coefficients exist such that Wigner-Yanase information is equal to Helstrom information. The latter constitutes an upper bound for the classical expected Fisher information, hence the inverse Wigner-Yanase information provides an approximate lower bound to the variance of an unbiased estimator of the parameter of interest. The advantage of approximating Helstrom's sharp bound lies in the fact that Wigner-Yanase information is straightforward to compute, while it is often very difficult to obtain a feasible expression for Helstrom information. In fact, the latter requires the solution of an implicit second order matrix differential equation, while the former requires just scalar differentiation.

  17. Analyzing Fish Condition Factor Index Through Skew-Gaussian Information Theory Quantifiers

    Science.gov (United States)

    Contreras-Reyes, Javier E.

    2016-06-01

    Biological-fishery indicators have been widely studied. As such the condition factor (CF) index, which interprets the fatness level of a certain species based on length and weight, has been investigated, too. However, CF has been studied without considering its temporal features and distribution. In this paper, we analyze the CF time series via skew-gaussian distributions that consider the asymmetry produced by extreme events. This index is characterized by a threshold autoregressive model and corresponds to a stationary process depending on the shape parameter of the skew-gaussian distribution. Then we use the Jensen-Shannon (JS) distance to compare CF by length classes. This distance has mathematical advantages over other divergences such as Kullback-Leibler and Jeffrey’s, and the triangular inequality property. Our results are applied to a biological catalogue of anchovy (Engraulis ringens) from the northern coast of Chile, for the period 1990-2010 that consider monthly CF time series by length classes and sex. We find that for high values of shape parameter, JS distance tends to be more sensible to detect discrepancies than Jeffrey’s divergence. In addition, the body condition of male anchovies with higher lengths coincides with the ending of the moderate-strong El Niño event 91-92 and for both males and females, the smaller lengths coincide with the beginning of the strong El Niño event 97-98.

  18. Quantum skew divergence

    Energy Technology Data Exchange (ETDEWEB)

    Audenaert, Koenraad M. R., E-mail: koenraad.audenaert@rhul.ac.uk [Department of Mathematics, Royal Holloway University of London, Egham TW20 0EX, United Kingdom and Department of Physics and Astronomy, University of Ghent, S9, Krijgslaan 281, B-9000 Ghent (Belgium)

    2014-11-15

    In this paper, we study the quantum generalisation of the skew divergence, which is a dissimilarity measure between distributions introduced by Lee in the context of natural language processing. We provide an in-depth study of the quantum skew divergence, including its relation to other state distinguishability measures. Finally, we present a number of important applications: new continuity inequalities for the quantum Jensen-Shannon divergence and the Holevo information, and a new and short proof of Bravyi's Small Incremental Mixing conjecture.

  19. Extension of EMA to address regional skew and low outliers

    Science.gov (United States)

    Griffis, V.W.; Stedinger, J.R.; Cohn, T.A.; Bizier, P.; DeBarry, P.

    2003-01-01

    The recently developed expected moments algorithm [EMA] (Cohn et al. 1997) does as well as MLEs at estimating LP3 flood quantiles using systematic and historical information. Needed extensions include use of a regional skewness estimator and its precision to be consistent with Bulletin 17B and to make use of such hydrologic information. Another issue addressed by Bulletin 17B is the treatment of low outliers. A Monte Carlo study illustrates the performance of an extended EMA estimator compared to estimators that employ the complete data set with and without use of regional skew, conditional probability adjustment from Bulletin 17B, and an estimator that uses probability plot regression to compute substitute values for low outliers. Estimators that use a regional skew all do better than estimators that fail to use an informative regional skewness estimator. For LP3 data, the low outlier rejection procedure results in no loss of overall accuracy, and the differences between the MSEs of the estimators that used an informative regional skew were generally negligible in the skew range of real interest.

  20. Evaluation of an adjustable epidemiologic information system.

    Directory of Open Access Journals (Sweden)

    Jiunn-Shyan Julian Wu

    Full Text Available BACKGROUND: In order to facilitate public health response and to achieve early control of infectious disease epidemics, an adjustable epidemiologic information system (AEIS was established in the Taiwan public health network in February 2006. METHODOLOGY/PRINCIPAL FINDINGS: The performance of AEIS for the period 2006 through 2008 was evaluated based on a number of response times (RT and the public health impact. After implementation of the system, the apparent overall shortened RT was mainly due to the shortening of personnel response time (PRT and the time needed to draft a new questionnaire that incurred as personnel-system interface (PSI; PRT dropped from a fluctuating range of 9.8 ∼28.8 days in the first four months to <10 days in the following months and remained low till 2008 (0.88±1.52 days. The PSIs for newly emerged infectious diseases were 2.6 and 3.4 person-hours for H5N1 in 2007 and chikungunya in 2008, respectively, a much improvement from 1142.5 person-hours for SARS in 2003. The duration of each rubella epidemic cluster was evaluated as public health impact and showed a shortening trend (p = 0.019 that concurred with the shortening of PRT from 64.8±47.3 to 25.2±38.2 hours per cluster (p<0.0001. CONCLUSIONS/SIGNIFICANCE: The first evaluation of the novel instrument AEIS that had been used to assist Taiwan's multi-level government for infectious diseases control demonstrated that it was well integrated into the existing public health infrastructure. It provided flexible tools and computer algorithms with friendly interface for timely data collection, integration, and analysis; as a result, it shortened RTs, filled in gaps of personnel lacking sufficient experiences, created a more efficient flow of response, and identified asymptomatic/mild cases early to minimize further spreading. With further development, AEIS is anticipated to be useful in the application of other acute public health events needing immediate

  1. The Structure of Adjustment Costs in Information Technology Investment

    OpenAIRE

    Hyunbae Chun; Sung-Bae Mun

    2005-01-01

    We examine the pattern of information technology (IT) capital adjustment using data from U.S. industries. Using the gap between actual and desired IT capital stocks, we estimate the shape of the adjustment cost function in IT investment. Both ordinary least squares and nonparametric regression estimates support irreversibility in IT investment.

  2. Cross-Informant Evaluations of Preschoolers' Adjustment in Different Cultures

    Science.gov (United States)

    Israelashvili, Moshe

    2017-01-01

    An accurate and agreed upon evaluation of preschoolers' behavior is crucial for young children's positive development. This study explores possible cultural differences in cross-informants' evaluations. The premise is that informants who are from different cultures tend to give different evaluations of preschoolers' adjustment and/or that the…

  3. Skewness preference across countries

    Directory of Open Access Journals (Sweden)

    Adam Zaremba

    2015-07-01

    Full Text Available Prospect theory implies that assets with positively skewed returns should be traded at premium to assets with negative skewness. We hypothesize that in the integrated financial markets this concept should also hold for the entire country equity portfolios. This article examines the linkages between the country-level expected returns and past skewness. We evidence a robust negative relationship between skewness and future returns. The phenomenon is most significant within large, liquid, developed, and open stock markets. Additional sorts on skewness can improve performance of both cross-country value and momentum strategies. The study is based on the sorting and cross-sectional tests conducted within a sample of 78 country equity markets for years 1999-2014.

  4. Skew-closed categories

    CERN Document Server

    Street, Ross

    2012-01-01

    Spurred by the new examples found by Kornel Szlach\\'anyi of a form of lax monoidal category, the author felt the time ripe to publish a reworking of Eilenberg-Kelly's original paper on closed categories appropriate to the laxer context. The new examples are connected with bialgebroids. With Stephen Lack, we have also used the concept to give an alternative definition of quantum category and quantum groupoid. Szlach\\'anyi has called the lax notion {\\em skew monoidal}. This paper defines {\\em skew closed category}, proves Yoneda lemmas for categories enriched over such, and looks at closed cocompletion.

  5. Information bias in health research: definition, pitfalls, and adjustment methods.

    Science.gov (United States)

    Althubaiti, Alaa

    2016-01-01

    As with other fields, medical sciences are subject to different sources of bias. While understanding sources of bias is a key element for drawing valid conclusions, bias in health research continues to be a very sensitive issue that can affect the focus and outcome of investigations. Information bias, otherwise known as misclassification, is one of the most common sources of bias that affects the validity of health research. It originates from the approach that is utilized to obtain or confirm study measurements. This paper seeks to raise awareness of information bias in observational and experimental research study designs as well as to enrich discussions concerning bias problems. Specifying the types of bias can be essential to limit its effects and, the use of adjustment methods might serve to improve clinical evaluation and health care practice.

  6. Mixtures of skewed Kalman filters

    KAUST Repository

    Kim, Hyoungmoon

    2014-01-01

    Normal state-space models are prevalent, but to increase the applicability of the Kalman filter, we propose mixtures of skewed, and extended skewed, Kalman filters. To do so, the closed skew-normal distribution is extended to a scale mixture class of closed skew-normal distributions. Some basic properties are derived and a class of closed skew. t distributions is obtained. Our suggested family of distributions is skewed and has heavy tails too, so it is appropriate for robust analysis. Our proposed special sequential Monte Carlo methods use a random mixture of the closed skew-normal distributions to approximate a target distribution. Hence it is possible to handle skewed and heavy tailed data simultaneously. These methods are illustrated with numerical experiments. © 2013 Elsevier Inc.

  7. Skewed Binary Search Trees

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Moruz, Gabriel

    2006-01-01

    It is well-known that to minimize the number of comparisons a binary search tree should be perfectly balanced. Previous work has shown that a dominating factor over the running time for a search is the number of cache faults performed, and that an appropriate memory layout of a binary search tree...... can reduce the number of cache faults by several hundred percent. Motivated by the fact that during a search branching to the left or right at a node does not necessarily have the same cost, e.g. because of branch prediction schemes, we in this paper study the class of skewed binary search trees....... For all nodes in a skewed binary search tree the ratio between the size of the left subtree and the size of the tree is a fixed constant (a ratio of 1/2 gives perfect balanced trees). In this paper we present an experimental study of various memory layouts of static skewed binary search trees, where each...

  8. ADJUSTMENT OF LEVELING NETWORK BY INFORMATION SPREAD ESTIMATION

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In practical parameter estimation,we have always chosen eitherLeast Squares Estimation(LSE) or Robust Estimation.Since the distribution of observations is unknown,to select a correct estimation method is very difficult.It is well known that if observations include gross errors,the result of LSE will be badly containinated.On the other hand,if observations do not include any gross errors,the result of robust estimation is not as good as that of LSE.To solve this problem,Wang (1999) developed an estimation method called Information Spread Estimation (ISE) based on the information spread principle.The ISE is a very good method for estimating one parameter which is very robust.However, most of instances in surveying data processing are multi-parameters' estimation,owing to the inherent restrictions of ISE,it can not be applied to the surveying data processing directly.To apply the good method to the field of surveying data processing widely,the author has done the research deeply.This paper applies ISE successfully to the adjustment of leveling network by using the specialties of leveling.

  9. 77 FR 13328 - Federal Acquisition Regulation; Information Collection; Davis Bacon Act-Price Adjustment (Actual...

    Science.gov (United States)

    2012-03-06

    ... Regulation; Information Collection; Davis Bacon Act--Price Adjustment (Actual Method) AGENCY: Department of... previously approved information collection requirement concerning the Davis-Bacon Act price adjustment... comments identified by Information Collection 9000- 0154, Davis Bacon Act--Price Adjustment (Actual...

  10. On Skew Triangular Matrix Rings

    Institute of Scientific and Technical Information of China (English)

    Wang Wei-liang; Wang Yao; Ren Yan-li

    2016-01-01

    Letαbe a nonzero endomorphism of a ring R, n be a positive integer and Tn(R,α) be the skew triangular matrix ring. We show that some properties related to nilpotent elements of R are inherited by Tn(R,α). Meanwhile, we determine the strongly prime radical, generalized prime radical and Behrens radical of the ring R[x;α]/(xn), where R[x;α] is the skew polynomial ring.

  11. Dimensions of attractors in pinched skew products

    OpenAIRE

    Gröger, M.; Jäger, T.

    2011-01-01

    We study dimensions of strange non-chaotic attractors and their associated physical measures in so-called pinched skew products, introduced by Grebogi and his coworkers in 1984. Our main results are that the Hausdorff dimension, the pointwise dimension and the information dimension are all equal to one, although the box-counting dimension is known to be two. The assertion concerning the pointwise dimension is deduced from the stronger result that the physical measure is rectifiable. Our findi...

  12. Multivariate extended skew-t distributions and related families

    KAUST Repository

    Arellano-Valle, Reinaldo B.

    2010-12-01

    A class of multivariate extended skew-t (EST) distributions is introduced and studied in detail, along with closely related families such as the subclass of extended skew-normal distributions. Besides mathematical tractability and modeling flexibility in terms of both skewness and heavier tails than the normal distribution, the most relevant properties of the EST distribution include closure under conditioning and ability to model lighter tails as well. The first part of the present paper examines probabilistic properties of the EST distribution, such as various stochastic representations, marginal and conditional distributions, linear transformations, moments and in particular Mardia’s measures of multivariate skewness and kurtosis. The second part of the paper studies statistical properties of the EST distribution, such as likelihood inference, behavior of the profile log-likelihood, the score vector and the Fisher information matrix. Especially, unlike the extended skew-normal distribution, the Fisher information matrix of the univariate EST distribution is shown to be non-singular when the skewness is set to zero. Finally, a numerical application of the conditional EST distribution is presented in the context of confidential data perturbation.

  13. Optimal Backward Perturbation Analysis for the Block Skew Circulant Linear Systems with Skew Circulant Blocks

    Directory of Open Access Journals (Sweden)

    Zhaolin Jiang

    2014-01-01

    Full Text Available We first give the block style spectral decomposition of arbitrary block skew circulant matrix with skew circulant blocks. Secondly, we obtain the singular value of block skew circulant matrix with skew circulant blocks as well. Finally, based on the block style spectral decomposition, we deal with the optimal backward perturbation analysis for the block skew circulant linear system with skew circulant blocks.

  14. Skew quantum Murnaghan-Nakayama rule

    CERN Document Server

    Konvalinka, Matjaz

    2011-01-01

    In this paper, we extend recent results of Assaf and McNamara on skew Pieri rule and skew Murnaghan-Nakayama rule to a more general identity, which gives an elegant expansion of the product of a skew Schur function with a quantum power sum function in terms of skew Schur functions. We give two proofs, one completely bijective in the spirit of Assaf-McNamara's original proof, and one via Lam-Lauve-Sotille's skew Littlewood-Richardson rule. We end with some conjectures for skew rules for Hall-Littlewood polynomials.

  15. Method of airborne SAR image match integrating multi-information for block adjustment

    Science.gov (United States)

    Yang, S. C.; Huang, G. M.; Zhao, Z.; Lu, L. J.

    2015-06-01

    For the automation of SAR image Block Adjustment, this paper proposed a method of SAR image matching integrating multiinformation. It takes full advantage of SAR image geometric information, feature information, gray-related information and external auxiliary terrain information for SAR image matching. And then Image Tie Points (ITPs) of Block Adjustment can be achieved automatically. The main parts of extracting ITPs automatically include: First, SAR images were rectified geometrically based on the geometric information and external auxiliary terrain information (existed DEM) before match. Second, ground grid points with a certain interval can be get in the block area and approximate ITPs were acquired based on external auxiliary terrain information. Then match reference point was extracted for homologous image blocks with Harris feature detection operator and ITPs were obtained with pyramid matching based on gray-related information. At last, ITPs were transferred from rectified images to original SAR images and used in block adjustment. In the experiment, X band airborne SAR images acquired by Chinese airborne SAR system - CASMSAR system were used to make up the block. The result had showed that the method is effective for block adjustment of SAR data.

  16. Dimensions of Attractors in Pinched Skew Products

    Science.gov (United States)

    Gröger, M.; Jäger, T.

    2013-05-01

    We study dimensions of strange non-chaotic attractors and their associated physical measures in so-called pinched skew products, introduced by Grebogi and his coworkers in 1984. Our main results are that the Hausdorff dimension, the pointwise dimension and the information dimension are all equal to one, although the box-counting dimension is known to be two. The assertion concerning the pointwise dimension is deduced from the stronger result that the physical measure is rectifiable. Our findings confirm a conjecture by Ding, Grebogi and Ott from 1989.

  17. Dimensions of attractors in pinched skew products

    CERN Document Server

    Gröger, M

    2011-01-01

    We study dimensions of strange non-chaotic attractors and their associated physical measures in so-called pinched skew products, introduced by Grebogi and his coworkers in 1984. Our main results are that the Hausdorff dimension, the pointwise dimension and the information dimension are all equal to one, although the box-counting dimension is known to be two. The assertion concerning the pointwise dimension is deduced from the stronger result that the physical measure is rectifiable. Our findings confirm a conjecture by Ding, Grebogi and Ott from 1989.

  18. Skew Pairs of Idempotents in Transformation Semigroups

    Institute of Scientific and Technical Information of China (English)

    T. S. BLYTH; M. H. ALMEIDA SANTOS

    2006-01-01

    An ordered pair (e, f) of idempotents of a regular semigroup is called a skew pair if ef is not idempotent whereas fe is idempotent. We have shown previously that there are four distinct types of skew pairs of idempotents. Here we investigate the ubiquity of such skew pairs in full transformation semigroups.

  19. A Pieri rule for skew shapes

    CERN Document Server

    Assaf, Sami; Lam, Thomas

    2009-01-01

    The Pieri rule expresses the product of a Schur function and a single row Schur function in terms of Schur functions. We extend the classical Pieri rule by expressing the product of a skew Schur function and a single row Schur function in terms of skew Schur functions. Like the classical rule, our rule involves simple additions of boxes to the original skew shape.

  20. The skewness of computer science

    CERN Document Server

    Franceschet, Massimo

    2009-01-01

    Computer science is a relatively young discipline combining science, engineering, and mathematics. The main flavors of computer science research involve the theoretical development of conceptual models for the different aspects of computing and the more applicative building of software artifacts and assessment of their properties. In the computer science publication culture, conferences are an important vehicle to quickly move ideas, and journals often publish deeper versions of papers already presented at conferences. These peculiarities of the discipline make computer science an original research field within the sciences, and, therefore, the assessment of classical bibliometric laws is particularly important for this field. In this paper, we study the skewness of the distribution of citations to journals and conference papers published in computer science venues. We find that the skewness in the distribution of mean citedness of different journals combines with the asymmetry in citedness of articles in eac...

  1. THE INFLUENCE OF STUDENTS’ PERCEPTION ON SOCIAL INFORMATION SERVICES AND INDEPENDENCE TO SELF ADJUSTMENT

    Directory of Open Access Journals (Sweden)

    Abdul Kholiq

    2017-02-01

    Full Text Available Abstract   The phenomenon that occurs is the seventh grade students of SMP N 22 Semarang has an average adaptability 70%, while the services of social information has been provided by the teacher of guidance and counseling regularly. In addition there is a significant difference in the level of student independence. The purpose of this study is to determine and analyze the influence of students' perception on social information services and independence to self adjustment seventh grade students of SMP N 22 Semarang. This research is an ex post facto with quantitative approach. The study population numbered 240 students sample taken by purposive sampling technique. Collecting data using psychological scale were tested for its validity and reliability. The data analysis used is simple and multiple linear regression. The results are (1 Perceptions of students on social information services influences self adjustment, (2 Independence influences self adjustment, and (3 Perceptions of students on social information services and independence influences self adjustment. Based on these results it can be predicted that the higher level of students' perceptions on the service of social information and independence, the adaptability of students will be increased. Therefore, it is suggested that teachers of guidance and counseling should provide services that fit the needs of students so that students have a better perception on social information services and also they should foster students' independence.

  2. Optimal Weak Lensing Skewness Measurements

    CERN Document Server

    Zhang, T J; Zhang, P; Dubinski, J; Zhang, Tong-Jie; Pen, Ue-Li; Zhang, Pengjie; Dubinski, John

    2003-01-01

    Weak lensing measurements are entering a precision era to statistically map the distribution of matter in the universe. The most common measurement has been of the variance of the projected surface density of matter, which corresponds to the induced correlation in alignments of background galaxies. This measurement of the fluctuations is insensitive to the total mass content, like using waves on the ocean to measure its depths. But when the depth is shallow as happens near a beach, waves become skewed. Similarly, a measurement of skewness in the projected matter distribution directly measures the total matter content of the universe. While skewness has already been convincingly detected, its constraint on cosmology is still weak. We address optimal analyses for the CFHT Legacy Survey in the presence of noise. We show that a compensated Gaussian filter with a width of 2.5 arc minutes optimizes the cosmological constraint, yielding $\\Delta \\Omega_m/\\Omega_m\\sim 10%$. This is significantly better than other filt...

  3. Multivariate-adjusted pharmacoepidemiologic analyses of confidential information pooled from multiple health care utilization databases.

    Science.gov (United States)

    Rassen, Jeremy A; Avorn, Jerry; Schneeweiss, Sebastian

    2010-08-01

    Mandated post-marketing drug safety studies require vast databases pooled from multiple administrative data sources which can contain private and proprietary information. We sought to create a method to conduct pooled analyses while keeping information private and allowing for full confounder adjustment. We propose a method based on propensity score (PS) techniques. A set of propensity scores are computed in each data-contributing center and a PS-adjusted analysis is then carried out on a pooled basis. The method is demonstrated in a study of the potentially negative effects of concurrent initiation of clopidogrel and proton pump inhibitors (PPIs) in four cohorts of patients assembled from North American claims data sources. Clinical outcomes were myocardial infarction (MI) hospitalization and hospitalization for revascularization procedure. Success of the method was indicated by equivalent performance of our PS-based method and traditional confounder adjustment. We also implemented and evaluated high-dimensional propensity scores and meta-analytic techniques. On both a pooled and individual cohort basis, we saw substantially similar point estimates and confidence intervals for studies adjusted by covariates and from privacy-maintaining propensity scores. The pooled, adjusted OR for MI hospitalization was 1.20 (95% confidence interval 1.03, 1.41) with individual variable adjustment and 1.16 (1.00, 1.36) with PS adjustment. The revascularization OR estimates differed by analysis and pooling yielded substantially similar results. We observed little difference in point estimates when we employed standard techniques or the proposed privacy-maintaining pooling method. We would recommend the technique in instances where multi-center studies require both privacy and multivariate adjustment. 2010 John Wiley & Sons, Ltd.

  4. Drug-Induced Nephrotoxicity and Dose Adjustment Recommendations: Agreement Among Four Drug Information Sources.

    Science.gov (United States)

    Bicalho, Millena Drumond; Soares, Danielly Botelho; Botoni, Fernando Antonio; Reis, Adriano Max Moreira; Martins, Maria Auxiliadora Parreiras

    2015-09-09

    : Hospitalized patients require the use of a variety of drugs, many of which individually or in combination have the potential to cause kidney damage. The use of potentially nephrotoxic drugs is often unavoidable, and the need for dose adjustment should be evaluated. This study is aimed at assessing concordance in information on drug-induced nephrotoxicity and dose adjustment recommendations by comparing four drug information sources (DRUGDEX(®), UpToDate(®), Medscape(®) and the Brazilian Therapeutic Formulary) using the formulary of a Brazilian public hospital. A total of 218 drugs were investigated. The global Fleiss' kappa coefficient was 0.265 for nephrotoxicity (p sources. Anti-infectives and anti-hypertensives were the main drugs cited as nephrotoxic by the different sources. There were no clear definitions for qualitative data or quantitative values for dose adjustments among the four information sources. There was no advice for dosing for a large number of the drugs in the international databases. The National Therapeutic Formulary offered imprecise dose adjustment recommendations for many nephrotoxic drugs. Discrepancies among information sources may have a clinical impact on patient care and contribute to drug-related morbidity and mortality.

  5. Drug-Induced Nephrotoxicity and Dose Adjustment Recommendations: Agreement Among Four Drug Information Sources

    Directory of Open Access Journals (Sweden)

    Millena Drumond Bicalho

    2015-09-01

    Full Text Available : Hospitalized patients require the use of a variety of drugs, many of which individually or in combination have the potential to cause kidney damage. The use of potentially nephrotoxic drugs is often unavoidable, and the need for dose adjustment should be evaluated. This study is aimed at assessing concordance in information on drug-induced nephrotoxicity and dose adjustment recommendations by comparing four drug information sources (DRUGDEX®, UpToDate®, Medscape® and the Brazilian Therapeutic Formulary using the formulary of a Brazilian public hospital. A total of 218 drugs were investigated. The global Fleiss’ kappa coefficient was 0.265 for nephrotoxicity (p < 0.001; CI 95%, 0.211–0.319 and 0.346 for recommendations (p < 0.001; CI 95%, 0.292–0.401, indicating fair concordance among the sources. Anti-infectives and anti-hypertensives were the main drugs cited as nephrotoxic by the different sources. There were no clear definitions for qualitative data or quantitative values for dose adjustments among the four information sources. There was no advice for dosing for a large number of the drugs in the international databases. The National Therapeutic Formulary offered imprecise dose adjustment recommendations for many nephrotoxic drugs. Discrepancies among information sources may have a clinical impact on patient care and contribute to drug-related morbidity and mortality.

  6. Drug-Induced Nephrotoxicity and Dose Adjustment Recommendations: Agreement Among Four Drug Information Sources

    Science.gov (United States)

    Bicalho, Millena Drumond; Soares, Danielly Botelho; Botoni, Fernando Antonio; Reis, Adriano Max Moreira; Martins, Maria Auxiliadora Parreiras

    2015-01-01

    Hospitalized patients require the use of a variety of drugs, many of which individually or in combination have the potential to cause kidney damage. The use of potentially nephrotoxic drugs is often unavoidable, and the need for dose adjustment should be evaluated. This study is aimed at assessing concordance in information on drug-induced nephrotoxicity and dose adjustment recommendations by comparing four drug information sources (DRUGDEX®, UpToDate®, Medscape® and the Brazilian Therapeutic Formulary) using the formulary of a Brazilian public hospital. A total of 218 drugs were investigated. The global Fleiss’ kappa coefficient was 0.265 for nephrotoxicity (p < 0.001; CI 95%, 0.211–0.319) and 0.346 for recommendations (p < 0.001; CI 95%, 0.292–0.401), indicating fair concordance among the sources. Anti-infectives and anti-hypertensives were the main drugs cited as nephrotoxic by the different sources. There were no clear definitions for qualitative data or quantitative values for dose adjustments among the four information sources. There was no advice for dosing for a large number of the drugs in the international databases. The National Therapeutic Formulary offered imprecise dose adjustment recommendations for many nephrotoxic drugs. Discrepancies among information sources may have a clinical impact on patient care and contribute to drug-related morbidity and mortality. PMID:26371029

  7. Children's Representations of Family Relationships, Peer Information Processing, and School Adjustment

    Science.gov (United States)

    Bascoe, Sonnette M.; Davies, Patrick T.; Sturge-Apple, Melissa L.; Cummings, E. Mark

    2009-01-01

    This study examined children's peer information processing as an explanatory mechanism underlying the association between their insecure representations of interparental and parent-child relationships and school adjustment in a sample of 210 first graders. Consistent with emotional security theory (P. T. Davies & E. M. Cummings, 1994), results…

  8. A proof for Rhiel's range estimator of the coefficient of variation for skewed distributions.

    Science.gov (United States)

    Rhiel, G Steven

    2007-02-01

    In this research study is proof that the coefficient of variation (CV(high-low)) calculated from the highest and lowest values in a set of data is applicable to specific skewed distributions with varying means and standard deviations. Earlier Rhiel provided values for d(n), the standardized mean range, and a(n), an adjustment for bias in the range estimator of micro. These values are used in estimating the coefficient of variation from the range for skewed distributions. The d(n) and an values were specified for specific skewed distributions with a fixed mean and standard deviation. In this proof it is shown that the d(n) and an values are applicable for the specific skewed distributions when the mean and standard deviation can take on differing values. This will give the researcher confidence in using this statistic for skewed distributions regardless of the mean and standard deviation.

  9. Dose adjustment guidelines for medications in patients with renal impairment: how consistent are drug information sources?

    Science.gov (United States)

    Khanal, A; Castelino, R L; Peterson, G M; Jose, M D

    2014-01-01

    It is known that patients with renal disease are often administered inappropriate dosages of drugs. A lack of quantitative data in the available drug information sources and inconsistency in dosing information may augment the problem of dosing error. To determine the concordance among five drug information sources regarding the dosing recommendations provided for drugs considered problematic in patients with renal impairment and to determine the consistency among the sources regarding the definition of renal impairment and categorisation of chronic kidney disease. Five standard drug information sources were reviewed for 61 drugs recommended to be used with caution in renal impairment. Information on recommendations for dosage adjustment in renal impairment was extracted and analysed. Further, the definition and classification of renal impairment were recorded. The recommendation for each drug was coded into six different categories and the intersource reliability was calculated. Only slight agreement was observed among the sources (Fleiss Kappa: 0.3). Qualitative data were not well defined, and there was a lack of consistency in quantitative values. Some drugs marked as contraindicated in one source were not mentioned as such in others. Also, drugs considered as not requiring dosage adjustment in one source had explicit recommendations in other sources. The definition and classification of renal impairment differed among the five information sources. There should be an evidence-based approach to drug dosage adjustment in order to bring uniformity to the recommendations. Regular updating of the content of the drug information sources is also important. © 2013 The Authors; Internal Medicine Journal © 2013 Royal Australasian College of Physicians.

  10. The standard error of the Pearson skew

    Directory of Open Access Journals (Sweden)

    Bradley Harding

    2015-02-01

    Full Text Available The Pearson skew is a measure of asymmetry of a distribution, based on the difference between the mean and the median of a distribution. Here we show how to calculate the Pearson skew, estimate its standard error and the confidence interval. The derivation is based on a population following a normal distribution. Simulations explored the validity of this expression when the normality assumption is met in comparison to when the normality assumption is not met. The standard error of the Pearson skew revealed very robust in case of non-normal populations, compared to the Fisher Skew as presented in Harding, Tremblay and Cousineau (2014.

  11. Skew-Flavored Dark Matter

    CERN Document Server

    Agrawal, Prateek; Fortes, Elaine C F S; Kilic, Can

    2015-01-01

    We explore a novel flavor structure in the interactions of dark matter with the Standard Model. We consider theories in which both the dark matter candidate, and the particles that mediate its interactions with the Standard Model fields, carry flavor quantum numbers. The interactions are skewed in flavor space, so that a dark matter particle does not directly couple to the Standard Model matter fields of the same flavor, but only to the other two flavors. This framework respects Minimal Flavor Violation, and is therefore naturally consistent with flavor constraints. We study the phenomenology of a benchmark model in which dark matter couples to right-handed charged leptons. In large regions of parameter space the dark matter can emerge as a thermal relic, while remaining consistent with the constraints from direct and indirect detection. The collider signatures of this scenario include events with multiple leptons and missing energy. These events exhibit a characteristic flavor pattern that may allow this cla...

  12. Rhesus monkeys (Macaca mulatta) adaptively adjust information seeking in response to information accumulated.

    Science.gov (United States)

    Tu, Hsiao-Wei; Pani, Alex A; Hampton, Robert R

    2015-11-01

    Metacognition consists of monitoring and control processes. Monitoring has been inferred when nonhumans use a "decline test" response to selectively escape difficult test trials. Cognitive control has been inferred from selective information-seeking behavior by nonhumans ignorant of needed knowledge. Here we describe a computerized paradigm that extends previous work and assesses dynamic interactions between monitoring and control. Monkeys classified images as containing birds, fish, flowers, or people. To-be-classified images were initially masked, and monkeys were trained to gradually reveal the images by touching a "reveal button." Monkeys could choose to classify images at any time or to reveal more of the images. Thus, they had the opportunity to assess when enough of an image had been revealed to support accurate classification. In Experiment 1, monkeys made more reveal responses before classifying when smaller amounts of the image were revealed by each button touch. In Experiment 2, to-be-classified images were shrunk and covered by 1 critical blocker among other blockers that did not provide information when removed. Monkeys made more reveal responses as the critical blocker was removed later in the trial. In Experiment 3, monkeys were presented with previously classified images with either more or fewer blockers obscuring the image than was the case when they chose to classify that image previously. Monkeys made more reveal responses when information was insufficient than when it was excessive. These results indicate that monkeys dynamically monitor evolving decision processes and adaptively collect information as necessary to maintain accuracy.

  13. Portfolio optimization with skewness and kurtosis

    Science.gov (United States)

    Lam, Weng Hoe; Jaaman, Saiful Hafizah Hj.; Isa, Zaidi

    2013-04-01

    Mean and variance of return distributions are two important parameters of the mean-variance model in portfolio optimization. However, the mean-variance model will become inadequate if the returns of assets are not normally distributed. Therefore, higher moments such as skewness and kurtosis cannot be ignored. Risk averse investors prefer portfolios with high skewness and low kurtosis so that the probability of getting negative rates of return will be reduced. The objective of this study is to compare the portfolio compositions as well as performances between the mean-variance model and mean-variance-skewness-kurtosis model by using the polynomial goal programming approach. The results show that the incorporation of skewness and kurtosis will change the optimal portfolio compositions. The mean-variance-skewness-kurtosis model outperforms the mean-variance model because the mean-variance-skewness-kurtosis model takes skewness and kurtosis into consideration. Therefore, the mean-variance-skewness-kurtosis model is more appropriate for the investors of Malaysia in portfolio optimization.

  14. Skewed factor models using selection mechanisms

    KAUST Repository

    Kim, Hyoung-Moon

    2015-12-21

    Traditional factor models explicitly or implicitly assume that the factors follow a multivariate normal distribution; that is, only moments up to order two are involved. However, it may happen in real data problems that the first two moments cannot explain the factors. Based on this motivation, here we devise three new skewed factor models, the skew-normal, the skew-tt, and the generalized skew-normal factor models depending on a selection mechanism on the factors. The ECME algorithms are adopted to estimate related parameters for statistical inference. Monte Carlo simulations validate our new models and we demonstrate the need for skewed factor models using the classic open/closed book exam scores dataset.

  15. RGB-D SLAM Based on Extended Bundle Adjustment with 2D and 3D Information

    Directory of Open Access Journals (Sweden)

    Kaichang Di

    2016-08-01

    Full Text Available In the study of SLAM problem using an RGB-D camera, depth information and visual information as two types of primary measurement data are rarely tightly coupled during refinement of camera pose estimation. In this paper, a new method of RGB-D camera SLAM is proposed based on extended bundle adjustment with integrated 2D and 3D information on the basis of a new projection model. First, the geometric relationship between the image plane coordinates and the depth values is constructed through RGB-D camera calibration. Then, 2D and 3D feature points are automatically extracted and matched between consecutive frames to build a continuous image network. Finally, extended bundle adjustment based on the new projection model, which takes both image and depth measurements into consideration, is applied to the image network for high-precision pose estimation. Field experiments show that the proposed method has a notably better performance than the traditional method, and the experimental results demonstrate the effectiveness of the proposed method in improving localization accuracy.

  16. RGB-D SLAM Based on Extended Bundle Adjustment with 2D and 3D Information.

    Science.gov (United States)

    Di, Kaichang; Zhao, Qiang; Wan, Wenhui; Wang, Yexin; Gao, Yunjun

    2016-08-13

    In the study of SLAM problem using an RGB-D camera, depth information and visual information as two types of primary measurement data are rarely tightly coupled during refinement of camera pose estimation. In this paper, a new method of RGB-D camera SLAM is proposed based on extended bundle adjustment with integrated 2D and 3D information on the basis of a new projection model. First, the geometric relationship between the image plane coordinates and the depth values is constructed through RGB-D camera calibration. Then, 2D and 3D feature points are automatically extracted and matched between consecutive frames to build a continuous image network. Finally, extended bundle adjustment based on the new projection model, which takes both image and depth measurements into consideration, is applied to the image network for high-precision pose estimation. Field experiments show that the proposed method has a notably better performance than the traditional method, and the experimental results demonstrate the effectiveness of the proposed method in improving localization accuracy.

  17. Adjusting for population heterogeneity: a framework for characterizing statistical information and developing efficient test statistics.

    Science.gov (United States)

    Rabinowitz, Daniel

    2003-05-01

    The focus of this work is the TDT-type and family-based test statistics used for adjusting for potential confounding due to population heterogeneity or misspecified allele frequencies. A variety of heuristics have been used to motivate and derive these statistics, and the statistics have been developed for a variety of analytic goals. There appears to be no general theoretical framework, however, that may be used to evaluate competing approaches. Furthermore, there is no framework to guide the development of efficient TDT-type and family-based methods for analytic goals for which methods have not yet been proposed. The purpose of this paper is to present a theoretical framework that serves both to identify the information which is available to methods that are immune to confounding due to population heterogeneity or misspecified allele frequencies, and to inform the construction of efficient unbiased tests in novel settings. The development relies on the existence of a characterization of the null hypothesis in terms of a completely specified conditional distribution of transmitted genotypes. An important observation is that, with such a characterization, when the conditioning event is unobserved or incomplete, there is statistical information that cannot be exploited by any exact conditional test. The main technical result of this work is an approach to computing test statistics for local alternatives that exploit all of the available statistical information. Copyright 2003 Wiley-Liss, Inc.

  18. GPDs at non-zero skewness in ADS/QCD model

    Science.gov (United States)

    Rinaldi, Matteo

    2017-08-01

    We study Generalized Parton Distribution functions (GPDs) usually measured in hard exclusive processes and encoding information on the three dimensional partonic structure of hadrons and their spin decomposition, for non-zero skewness within the AdS/QCD formalism. To this aim the canonical scheme to calculate GPDs at zero skewness has been properly generalized. Furthermore, we show that the latter quantities, in this non-forward regime, are sensitive to non-trivial details of the hadronic light front wave function, such as a kind of parton correlations usually not accessible in studies of form factors and GPDs at zero skewness.

  19. Right Skewed Distribution of Activity Times in PERT

    Directory of Open Access Journals (Sweden)

    N.Ravi Shankar,

    2011-04-01

    Full Text Available A usual supposition in project management is that the distribution for most activities in a project network is right skewed. The prime objective of this paper is to find new path float in Program Evaluation and Review Technique (PERT for right skewed distribution of activity times in a project network. The new path float concept will bring useful planning information to the decision managers and the planners in the project construction. Our new path float in PERT are compared with normal, lognormal approximations with two parameters and also with beta approximations with three parameters. The comparison reveals that beta approximations with three parameters performs better than normal and lognormal approximations suggested.

  20. An Evaluation of the Adjusted DeLone and McLean Model of Information Systems Success; the case of financial information system in Ferdowsi University of Mashhad

    OpenAIRE

    Mohammad Lagzian; Shamsoddin Nazemi; Fatemeh Dadmand

    2012-01-01

    Assessing the success of information systems within organizations has been identified as one of the most critical subjects of information system management in both public and private organizations. It is therefore important to measure the success of information systems from the user's perspective. The purpose of the current study was to evaluate the degree of information system success by the adjusted DeLone and McLean’s model in the field financial information system (FIS) in an Iranian Univ...

  1. Modification of QUICK scheme by skew points

    Energy Technology Data Exchange (ETDEWEB)

    Mirzaei, M.; Mohammadi, R.; Malekzadeh, M. [K.N. Toosi Univ. of Technology, Aerospace Engineering Dept., Tehran (Iran, Islamic Republic of)]. E-mail: Mirzaei@kntu.ac.ir

    2005-07-01

    This paper presents a new method for convective flux approximation based on inclusions of skew points. The scheme uses the truncated terms of QUICK scheme and with the aid of an equation extracted from momentum equations, the skew points will appear in the convective flux formula. The results show that the presented scheme has better accuracy than the other schemes. Diffusion fluxes are approximated using power law scheme and for evaluation of the performance of the presented method several test cases were carried out and the results are compared with the results of other numerical works and experimental data. (author)

  2. A Statistical Model of Skewed Associativity

    OpenAIRE

    Michaud, Pierre

    2002-01-01

    This paper presents a statistical model of set-associativity, victim caching and skewed-associativity, with an emphasis on skewed-associativity. We show that set-associativity is not efficient when the working-set size is close to the cache size. We refer to this as the unit working-set problem. We show that victim-caching is not a practical solution to the unit working-se- t problem either, although victim caching emulates full associativity for working-sets much larger than the victim buffe...

  3. Skew chicane based betatron eigenmode exchange module

    Science.gov (United States)

    Douglas, David

    2010-12-28

    A skewed chicane eigenmode exchange module (SCEEM) that combines in a single beamline segment the separate functionalities of a skew quad eigenmode exchange module and a magnetic chicane. This module allows the exchange of independent betatron eigenmodes, alters electron beam orbit geometry, and provides longitudinal parameter control with dispersion management in a single beamline segment with stable betatron behavior. It thus reduces the spatial requirements for multiple beam dynamic functions, reduces required component counts and thus reduces costs, and allows the use of more compact accelerator configurations than prior art design methods.

  4. Anticipatory Postural Adjustments associated with reaching movements are programmed according to the availability of visual information.

    Science.gov (United States)

    Esposti, Roberto; Bruttini, Carlo; Bolzoni, Francesco; Cavallari, Paolo

    2017-02-17

    During goal-directed arm movements, the eyes, head, and arm are coordinated to look at and reach the target. We examined whether the expectancy of visual information about the target modifies Anticipatory Postural Adjustments (APAs). Ten standing subjects had to (1) move the eyes, head and arm, so as to reach, with both gaze and index-finger, a target of known position placed outside their visual field (Gaze-Reach); (2) look at the target while reaching it (Reach in Full Vision); (3) keep the gaze away until having touched it (Reach then Gaze) and (4) just Gaze without Reach the target. We recorded eye, head, right arm, and acromion kinematics, EMGs from upper- and lower-limb muscles, and forces exerted on the ground. In Gaze-Reach, two coordination strategies were found: when gaze preceded arm muscle recruitment (Gaze-first) and when the opposite occurred (Reach-first). APAs in acromion kinematics, leg muscles, and ground forces started significantly earlier in Gaze-first vs. Reach-first (mean time advance: 44.3 ± 8.9 ms), as it was in Reach in Full Vision vs. Reach then Gaze (39.5 ± 7.9 ms). The Gaze-first to Reach-first time-shift was similar to that between Reach in Full Vision and Reach then Gaze (p = 0.58). Moreover, Gaze without Reach data witnessed that the head-induced postural actions did not affect the APA onset in Gaze-first and Reach-first. In conclusion, in Gaze-first, the central control of posture considers visual information while planning the movement, like in Reach in Full Vision; while Reach-first is more similar to Reach then Gaze, where vision is not required.

  5. Adjusting the information service strategies according to users’ requirements—A survey of the library users’ information requirements in the four library systems of Zhejiang province

    Institute of Scientific and Technical Information of China (English)

    XU; Puying

    2009-01-01

    Based on a survey of the circumstances of the information requirements in social science from more than 3,800 library users in 48 libraries of the four major library systems in Zhejiang Province,this paper analyzes the present main characteristics of the users’requirements to the social science document information and puts forward some proposals for adjusting the document information service strategies for the library and information institutions.

  6. Investors’ Risk Preference Characteristics and Conditional Skewness

    Directory of Open Access Journals (Sweden)

    Fenghua Wen

    2014-01-01

    Full Text Available Perspective on behavioral finance, we take a new look at the characteristics of investors’ risk preference, building the D-GARCH-M model, DR-GARCH-M model, and GARCHC-M model to investigate their changes with states of gain and loss and values of return together with other time-varying characteristics of investors’ risk preference. Based on a full description of risk preference characteristic, we develop a GARCHCS-M model to study its effect on the return skewness. The top ten market value stock composite indexes from Global Stock Exchange in 2012 are adopted to make the empirical analysis. The results show that investors are risk aversion when they gain and risk seeking when they lose, which effectively explains the inconsistent risk-return relationship. Moreover, the degree of risk aversion rises with the increasing gain and that of risk seeking improves with the increasing losses. Meanwhile, we find that investors’ inherent risk preference in most countries displays risk seeking, and their current risk preference is influenced by last period’s risk preference and disturbances. At last, investors’ risk preferences affect the conditional skewness; specifically, their risk aversion makes return skewness reduce, while risk seeking makes the skewness increase.

  7. Objective Bayesian Analysis of Skew- t Distributions

    KAUST Repository

    BRANCO, MARCIA D'ELIA

    2012-02-27

    We study the Jeffreys prior and its properties for the shape parameter of univariate skew-t distributions with linear and nonlinear Student\\'s t skewing functions. In both cases, we show that the resulting priors for the shape parameter are symmetric around zero and proper. Moreover, we propose a Student\\'s t approximation of the Jeffreys prior that makes an objective Bayesian analysis easy to perform. We carry out a Monte Carlo simulation study that demonstrates an overall better behaviour of the maximum a posteriori estimator compared with the maximum likelihood estimator. We also compare the frequentist coverage of the credible intervals based on the Jeffreys prior and its approximation and show that they are similar. We further discuss location-scale models under scale mixtures of skew-normal distributions and show some conditions for the existence of the posterior distribution and its moments. Finally, we present three numerical examples to illustrate the implications of our results on inference for skew-t distributions. © 2012 Board of the Foundation of the Scandinavian Journal of Statistics.

  8. Prospective prediction of college adjustment using self- and informant-rated personality traits.

    Science.gov (United States)

    Kurtz, John E; Puher, Meredith A; Cross, Nicole A

    2012-01-01

    Studies that relate normal personality traits to students' adjustment to college have relied heavily on self-rating methods, concurrent designs, and academic performance indicators as criteria. We conducted a prospective study of high school seniors with a follow-up assessment made near the end of their freshman year of college. Self-ratings of personality traits and college adjustment were obtained from 90 students using the revised NEO personality inventory (NEO PI-R; Costa & McCrae, 1992) and the student adaptation to college questionnaire (SACQ; Baker & Siryk, 1989 ). Ratings of personality were also obtained from parents (n = 66) and same-sex peers from the college setting (n = 78) using the NEO five-factor inventory (NEO-FFI; Costa & McCrae, 1992 ). SACQ academic adjustment was correlated with conscientiousness ratings by all three sources and with openness ratings by parents and peers. SACQ Social Adjustment was correlated with self-ratings of neuroticism and peer ratings of extraversion. SACQ personal-emotional adjustment was correlated with self-ratings and parent ratings of neuroticism. Ratings by parents and peers showed significant incremental validity over self-ratings in the prediction of certain trait-adjustment relationships.

  9. Skew Pieri Rules for Hall-Littlewood Functions

    CERN Document Server

    Konvalinka, Matjaz

    2012-01-01

    We produce skew Pieri Rules for Hall--Littlewood functions in the spirit of Assaf and McNamara. The first two were conjectured by the first author. The key ingredients in the proofs are a q-binomial identity for skew partitions and a Hopf algebraic identity that expands products of skew elements in terms of the coproduct and the antipode.

  10. Categorification of skew-symmetrizable cluster algebras

    CERN Document Server

    Demonet, Laurent

    2009-01-01

    We propose a new framework for categorifying skew-symmetrizable cluster algebras. Starting from an exact stably 2-Calabi-Yau category C endowed with the action of a finite group G, we construct a G-equivariant mutation on the set of maximal rigid G-invariant objects of C. Using an appropriate cluster character, we can then attach to these data an explicit skew-symmetrizable cluster algebra. As an application we prove the linear independence of the cluster monomials in this setting. Finally, we illustrate our construction with examples associated with partial flag varieties and unipotent subgroups of Kac-Moody groups, generalizing to the non simply-laced case several results of Gei\\ss-Leclerc-Schr\\"oer.

  11. Topological Conjugacy Between Skew Tent Maps

    Science.gov (United States)

    Shi, Yong-Guo; Wang, Zhihua

    This paper investigates the conjugacy of any two skew tent maps. An explicit formula is given for the conjugacy. It is proved that the conjugacy is singular, Hölder continuous and not differentiable as well as its inverse. We calculate the arc-length of the conjugacy curve and the area under the conjugacy curve. We construct a sequence of functions to approximate the conjugacy, and give an estimation for the error of the approximation.

  12. Linear algebra for skew-polynomial matrices

    OpenAIRE

    Abramov, Sergei; Bronstein, Manuel

    2002-01-01

    We describe an algorithm for transforming skew-polynomial matrices over an Ore domain in row-reduced form, and show that this algorithm can be used to perform the standard calculations of linear algebra on such matrices (ranks, kernels, linear dependences, inhomogeneous solving). The main application of our algorithm is to desingularize recurrences and to compute the rational solutions of a large class of linear functional systems. It also turns out to be efficient when applied to ordinary co...

  13. Maximal Subgroups of Skew Linear Groups

    Institute of Scientific and Technical Information of China (English)

    M. Mahdavi-Hezavehi

    2002-01-01

    Let D be an infinite division algebra of finite dimension over its centre Z(D) = F, and n a positive integer. The structure of maximal subgroups of skew linear groups are investigated. In particular, assume N is a normal subgroup of GLn(D) and M is a maximal subgroup of N containing Z(N). It is shown that if M/Z(N) is finite, then N is central.

  14. 3D skewing and de-skewing scheme for conflict-free access to rays in volume rendering

    Energy Technology Data Exchange (ETDEWEB)

    Cohen-or, D.; Kaufman, A. [Tel-Aviv Univ., Ramat Aviv (Israel)

    1995-05-01

    We extend a 2D linear skewed memory organization to 3D and introduce the associated de-skewing scheme designed to provide conflict-free access to projection rays of voxels for use in a volume rendering architecture. This is an application of a 3D linear skewing scheme which supports real-time axonometric projection from 26 primary orientations. 17 refs.

  15. The past, present and future of reproductive skew theory and experiments.

    Science.gov (United States)

    Nonacs, Peter; Hager, Reinmar

    2011-05-01

    A major evolutionary question is how reproductive sharing arises in cooperatively breeding species despite the inherent reproductive conflicts in social groups. Reproductive skew theory offers one potential solution: each group member gains or is allotted inclusive fitness equal to or exceeding their expectation from reproducing on their own. Unfortunately, a multitude of skew models with conflicting predictions has led to confusion in both testing and evaluating skew theory. The confusion arises partly because one set of models (the 'transactional' type) answer the ultimate evolutionary question of what ranges of reproductive skew can yield fitness-enhancing solutions for all group members. The second set of models ('compromise') give an evolutionarily proximate, game-theoretic evolutionarily stable state (ESS) solution that determines reproductive shares based on relative competitive abilities. However, several predictions arising from compromise models require a linear payoff to increased competition and do not hold with non-linear payoffs. Given that for most species it may be very difficult or impossible to determine the true relationship between effort devoted to competition and reproductive share gained, compromise models are much less predictive than previously appreciated. Almost all skew models make one quantitative prediction (e.g. realized skew must fall within ranges predicted by transactional models), and two qualitative predictions (e.g. variation in relatedness or competitive ability across groups affects skew). A thorough review of the data finds that these three predictions are relatively rarely supported. As a general rule, therefore, the evolution of cooperative breeding appears not to be dependent on the ability of group members to monitor relatedness or competitive ability in order to adjust their behaviour dynamically to gain reproductive share. Although reproductive skew theory fails to predict within-group dynamics consistently, it does

  16. An Evaluation of the Adjusted DeLone and McLean Model of Information Systems Success; the case of financial information system in Ferdowsi University of Mashhad

    Directory of Open Access Journals (Sweden)

    Mohammad Lagzian

    2012-07-01

    Full Text Available Assessing the success of information systems within organizations has been identified as one of the most critical subjects of information system management in both public and private organizations. It is therefore important to measure the success of information systems from the user's perspective. The purpose of the current study was to evaluate the degree of information system success by the adjusted DeLone and McLean’s model in the field financial information system (FIS in an Iranian University. The relationships among the dimensions in an extended systems success measurement framework were tested. Data were collected by questionnaire from end-users of a financial information system at Ferdowsi University of Mashhad. The adjusted DeLone and McLean model was contained five variables (system quality, information quality, system use, user satisfaction, and individual impact. The results revealed that system quality was significant predictor of system use, user satisfaction and individual impact. Information quality was also a significant predictor of user satisfaction and individual impact, but not of system use. System use and user satisfaction were positively related to individual impact. The influence of user satisfaction on system use was insignificant

  17. 76 FR 74700 - Revision of Patent Term Adjustment Provisions Relating to Information Disclosure Statements

    Science.gov (United States)

    2011-12-01

    ... definition ``a communication that was issued by a patent office in a counterpart foreign or international..., Courts, Freedom of information, Inventions and patents, Reporting and recordkeeping requirements,...

  18. The underpricing of Brazilian IPOs and the adjustment to public and private information

    Directory of Open Access Journals (Sweden)

    Ricardo R.G. Avelino

    2013-03-01

    Full Text Available This paper examines the underwriters' treatment of information throughout the IPO pricing process based on a sample of Brazilian companies that went public between 2004 and 2011. There is evidence that the offer price partially incorporates the information contained into the Bovespa index during the book-building period, reacting symmetrically to upward and downward movements. The first-day return, as a result, is predictable on the basis of this information. Positive private information disclosed during the book-building period is also partially incorporated into the offer price. Issues priced above the midpoint of the initial price range are associated with higher initial returns.

  19. Coherence for Skew-Monoidal Categories

    Directory of Open Access Journals (Sweden)

    Tarmo Uustalu

    2014-06-01

    Full Text Available I motivate a variation (due to K. Szlachányi of monoidal categories called skew-monoidal categories where the unital and associativity laws are not required to be isomorphisms, only natural transformations. Coherence has to be formulated differently than in the well-known monoidal case. In my (to my knowledge new version, it becomes a statement of uniqueness of normalizing rewrites. I present a proof of this coherence theorem and also formalize it fully in the dependently typed programming language Agda.

  20. Influence of Information Related to Child Physical Abuse on Professional Ratings of Adjustment and Prognosis.

    Science.gov (United States)

    DeRoma, Virginia M.; And Others

    1997-01-01

    This study examined the influence of access to information of a history of physical maltreatment on evaluative responses of 40 social services and clinical psychology professionals. Findings verified the influence of such information on professional judgments and point to a possible pattern of erroneous judgments. (Author/PB)

  1. SKEWNESS OF RETURN DISTRIBUTION AND COEFFICIENT OF RISK PREMIUM

    Institute of Scientific and Technical Information of China (English)

    Fenghua WEN; Xiaoguang YANG

    2009-01-01

    The skewness of the return distribution is one of the important features of the security price. In this paper, the authors try to explore the relationship between the skewness and the coefficient of risk premium. The coefficient of the risk premium is estimated by a GARCH-M model, and the robust measurement of skewness is calculated by Groeneveld-Meeden method. The empirical evidences for the composite indexes from 33 securities markets in the world indicate that the risk compensation requirement in the market where the return distribution is positively skewed is virtually zero, and the risk compensation requirement is positive in a significant level in the market where the return distribution is negative skewed. Moreover, the skewness is negatively correlated with the coefficient of the risk premium.

  2. Bayesian modeling growth curves for quail assuming skewness in errors

    Directory of Open Access Journals (Sweden)

    Robson Marcelo Rossi

    2014-06-01

    Full Text Available Bayesian modeling growth curves for quail assuming skewness in errors - To assume normal distributions in the data analysis is common in different areas of the knowledge. However we can make use of the other distributions that are capable to model the skewness parameter in the situations that is needed to model data with tails heavier than the normal. This article intend to present alternatives to the assumption of the normality in the errors, adding asymmetric distributions. A Bayesian approach is proposed to fit nonlinear models when the errors are not normal, thus, the distributions t, skew-normal and skew-t are adopted. The methodology is intended to apply to different growth curves to the quail body weights. It was found that the Gompertz model assuming skew-normal errors and skew-t errors, respectively for male and female, were the best fitted to the data.

  3. Skewed norms under peer pressure: Formation and collapse

    OpenAIRE

    Michaeli, Moti; Spiro, Daniel

    2014-01-01

    This paper shows that peer pressure may lead to dynamic convergence to a norm that is skewed with respect to preferences in society, yet is endogenously upheld by the population. Moreover, a skewed norm will often be more sustainable than a representative norm. This may explain the skewness of various social and religious norms. By furthermore interpreting a norm as a political regime, we show that biased regimes can be sustained even without the existence of a powerful group with coherent in...

  4. Coefficient of variation calculated from the range for skewed distributions.

    Science.gov (United States)

    Rhiel, G Steven

    2006-02-01

    In this research a coefficient of variation (CVS(high.low)) is developed that is calculated from the highest and lowest values in a set of data for samples from skewed distributions. A correction factor is determined such that CVS(high-low) is a dose estimate of the population coefficient of variation when sampling from three skewed chi-squared distributions and three skewed empirical distributions. The empirical distributions are from "real-world" data sets in psychology and education.

  5. 77 FR 70832 - Comment Request for Information Collection for Trade Adjustment Assistance (TAA) Reserve Funding...

    Science.gov (United States)

    2012-11-27

    ... Labor, 200 Constitution Avenue NW., Washington, DC 20210. Telephone number: 202-693-3236 (this is not a toll-free number). Individuals with hearing or speech impairments may access the telephone number above via TTY by calling the toll-free Federal Information Relay Service at 1-877-889-5627 (TTY/TDD)....

  6. Skew Detection for Binary Document Images Using Mathematical Morphyology

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The input document images with skew can be a serious problem in the optical character recognition system. A method is proposed for skew detection in binary document images using mathematic morphology. The basic process of our approach consists of three steps: Firstly, a dilation operation is applied to the binary image; Secondly, the dilated image is thinned; Finally, the skew angle is detected using the Hough transform. The proposed approach with high precision can detect skew with large angle (-90°-90°). The experimental result shows this method is applicable and efficient.

  7. Robust skew estimation using straight lines in document images

    Science.gov (United States)

    Koo, Hyung Il; Cho, Nam Ik

    2016-05-01

    A skew-estimation method using straight lines in document images is presented. Unlike conventional approaches exploiting the properties of text, we formulate the skew-estimation problem as an estimation task using straight lines in images and focus on robust and accurate line detection. To be precise, we adopt a block-based edge detector followed by a progressive line detector to take clues from a variety of sources such as text lines, boundaries of figures/tables, vertical/horizontal separators, and boundaries of textblocks. Extensive experiments on the datasets of skewed images and competition results reveal that the proposed method works robustly and yields accurate skew-estimation results.

  8. ON SKEW-NORMAL MODEL FOR ECONOMICALLY ACTIVE POPULATION

    Directory of Open Access Journals (Sweden)

    OLOSUNDE AKINLOLU A

    2011-04-01

    Full Text Available The literature related to skew-symmetric distribution have grown rapidly in recent years but at the moment no publication on its applications concerning the description of economically active data with this type of probability models. In this paper, we provided an extension to this skew-normal distribution, which is also part of the family of skewed class of normal but with additional shape parameters δ. Some properties of this distribution are presented and finally, we considered fitting it to economically active population data. The model exhibited a better behaviour when compared to normal and skew normal distributions.

  9. Skew t distribution and its moments

    Institute of Scientific and Technical Information of China (English)

    Saralees NADARAJAH; Arjun K.GUPTA

    2006-01-01

    A random variable X is said to have the skew- t distribution if its pdf is f (x) = 2g (x) G (λx), where g (·) and G(·), respectively, denote the pdf and the cdf of the Student's t distribution with degrees of freedom ν. The moments of this distribution appear not to have been studied in detail. In this paper, we derive general expressions for the nth moment of X by considering the cases ν odd and ν even separately. These expressions turn out to involve sums of the Gauss hypergeometric function. We also provide closed form expressions for the moments of X for the particular cases ν = 2, …, 10.

  10. Mutation classes of skew-symmetrizable 3x3 matrices

    CERN Document Server

    Seven, Ahmet

    2010-01-01

    In this paper, we determine representatives for the mutation classes of skew-symmetrizable 3x3 matrices and associated graphs using a natural minimality condition, generalizing and strengthening results of Beineke-Brustle-Hille and Felikson-Shapiro-Tumarkin. Furthermore, we obtain a new numerical invariant for the mutation operation on skew-symmetrizable matrices of arbitrary size.

  11. Skew Littlewood-Richardson rules from Hopf algebras

    CERN Document Server

    Lam, Thomas; Sottile, Frank

    2009-01-01

    We use Hopf algebras to prove a version of the Littlewood-Richardson formula for skew Schur functions, which implies a conjecture of Assaf and McNamara. We also establish a similar skew Littlewood-Richardson formula for Schur P- and Q-functions.

  12. Multivariate skew- t approach to the design of accumulation risk scenarios for the flooding hazard

    Science.gov (United States)

    Ghizzoni, Tatiana; Roth, Giorgio; Rudari, Roberto

    2010-10-01

    The multivariate version of the skew- t distribution provides a powerful analytical description of the joint behavior of multivariate processes. It enjoys valuable properties: from the aptitude to model skewed as well as leptokurtic datasets to the availability of moments and likelihood analytical expressions. Moreover, it offers a wide range of extremal dependence strength, allowing for upper and lower tail dependence. The idea underneath this work is to employ the multivariate skew- t distribution to provide an estimation of the joint probability of flood events in a multi-site multi-basin approach. This constitutes the basis for the design and evaluation of flood hazard scenarios for large areas in terms of their intensity, extension and frequency, i.e. those information required by civil protection agencies to put in action mitigation strategies and by insurance companies to price the flooding risk and to evaluate portfolios. Performances of the skew- t distribution and the corresponding t copula function, introduced to represent the state of the art for multivariate simulations, are discussed with reference to the Tanaro Basin, North-western Italy. To enhance the characteristics of the correlation structure, three nested and non-nested gauging stations are selected with contributing areas from 1500 to 8000 km 2. A dataset of 76 trivariate flood events is extracted from a mean daily discharges database available for the time period from January 1995 to December 2003. Applications include the generation of multivariate skew- t and t copula samples and models' comparison through the principle of minimum cross-entropy, here revised for the application to multivariate samples. Copula and skew- t based scenario return period estimations are provided for the November 1994 flood event, i.e. the worst on record in the 1801-2001 period. Results are encouraging: the skew- t distribution seems able to describe the joint behavior, being close to the observations. Marginal

  13. On the Construction of Skew Quasi-Cyclic Codes

    CERN Document Server

    Abualrub, Taher; Aydin, Nuh; Siap, Irfan

    2008-01-01

    In this paper we study a special type of quasi-cyclic (QC) codes called skew QC codes. This set of codes is constructed using a non-commutative ring called the skew polynomial rings $F[x;\\theta ]$. After a brief description of the skew polynomial ring $F[x;\\theta ]$ it is shown that skew QC codes are left submodules of the ring $R_{s}^{l}=(F[x;\\theta ]/(x^{s}-1))^{l}.$ The notions of generator and parity-check polynomials are given. We also introduce the notion of similar polynomials in the ring $F[x;\\theta ]$ and show that parity-check polynomials for skew QC codes are unique up to similarity. Our search results lead to the construction of several new codes with Hamming distances exceeding the Hamming distances of the previously best known linear codes with comparable parameters.

  14. How Small Is Big: Sample Size and Skewness.

    Science.gov (United States)

    Piovesana, Adina; Senior, Graeme

    2016-09-21

    Sample sizes of 50 have been cited as sufficient to obtain stable means and standard deviations in normative test data. The influence of skewness on this minimum number, however, has not been evaluated. Normative test data with varying levels of skewness were compiled for 12 measures from 7 tests collected as part of ongoing normative studies in Brisbane, Australia. Means and standard deviations were computed from sample sizes of 10 to 100 drawn with replacement from larger samples of 272 to 973 cases. The minimum sample size was determined by the number at which both mean and standard deviation estimates remained within the 90% confidence intervals surrounding the population estimates. Sample sizes of greater than 85 were found to generate stable means and standard deviations regardless of the level of skewness, with smaller samples required in skewed distributions. A formula was derived to compute recommended sample size at differing levels of skewness.

  15. Characteristic functions of scale mixtures of multivariate skew-normal distributions

    KAUST Repository

    Kim, Hyoung-Moon

    2011-08-01

    We obtain the characteristic function of scale mixtures of skew-normal distributions both in the univariate and multivariate cases. The derivation uses the simple stochastic relationship between skew-normal distributions and scale mixtures of skew-normal distributions. In particular, we describe the characteristic function of skew-normal, skew-t, and other related distributions. © 2011 Elsevier Inc.

  16. Real quartic surfaces containing 16 skew lines

    Directory of Open Access Journals (Sweden)

    Isidro Nieto

    2004-01-01

    Full Text Available It is well known that there is an open three-dimensional subvariety Ms of the Grassmannian of lines in ℙ3 which parametrizes smooth irreducible complex surfaces of degree 4 which are Heisenberg invariant, and each quartic contains 32 lines but only 16 skew lines, being determined by its configuration of lines, are called a double 16. We consider here the problem of visualizing in a computer the real Heisenberg invariant quartic surface and the real double 16. We construct a family of points l∈Ms parametrized by a two-dimensional semialgebraic variety such that under a change of coordinates of l into its Plüecker, coordinates transform into the real coordinates for a line L in ℙ3, which is then used to construct a program in Maple 7. The program allows us to draw the quartic surface and the set of transversal lines to L. Additionally, we include a table of a group of examples. For each test example we specify a parameter, the viewing angle of the image, compilation time, and other visual properties of the real surface and its real double 16. We include at the end of the paper an example showing the surface containing the double 16.

  17. Nilradicals of skew Hurwitz series of rings

    Directory of Open Access Journals (Sweden)

    Morteza Ahmadi

    2015-05-01

    Full Text Available ‎For a ring endomorphism α of a ring R, ‎Krempa called α a rigid endomorphism if aα(a=0 implies a = 0 for a in R. ‎A ring R is called rigid if there exists a rigid endomorphism of R. ‎In this paper‎, ‎we extend the α-rigid property of a ring R to the upper nilradical N_r(R of R. ‎For an endomorphism α and the upper nilradical N_r(R of a ring R, ‎we introduce the condition (*: ‎N_r(R is a α-ideal of R and aα(a in N_r(R implies a in N_r(R for a in R. ‎We study characterizations of a ring R with an endomorphism α satisfying the condition (*, ‎and we investigate their related properties‎. ‎The connections between the upper nilradical of R and the upper nilradical of the skew Hurwitz series ring (HR,α of R are also investigated‎.

  18. Executive functions, social information processing, and social adjustment in young children born with very low birth weight.

    Science.gov (United States)

    Wolfe, Kelly R; Vannatta, Kathryn; Nelin, Mary Ann; Yeates, Keith Owen

    2015-01-01

    Children born with very low birth weight (VLBW) are at risk for neurocognitive and behavioral sequelae. Although VLBW infants are at higher risk for deficits in executive functions (EFs) and social functioning during school-age years, few studies have investigated those sequelae or their association in young children born VLBW. We examined the associations between EFs and social functioning in preterm, VLBW children age 4-6 years (n = 20) and matched, term-born, normal birth weight controls admitted to the neonatal intensive care unit (NICU) after birth (n = 18). The groups did not differ significantly on measures of EFs, social information processing, or parent-reported social adjustment. The VLBW group had lower IQs than controls, though both group means were in the average range. Within the VLBW group, medical predictors of better EFs included older gestational age at birth and no history of bronchopulmonary dysplasia. Across groups, EFs and social information processing were positively correlated. Deficits in EFs and social functioning may emerge after the preschool years in VLBW children, or improved care of children born VLBW may be reducing the cognitive and psychosocial sequelae observed in earlier cohorts. Among children born VLBW, early EFs may be directly related to social information processing.

  19. Seismic response of skewed RC box-girder bridges

    Institute of Scientific and Technical Information of China (English)

    Ahmed Abdel-Mohti; Gokhan Pekcan

    2008-01-01

    It is critical to ensure the functionality of highway bridges after earthquakes to provide access to important facilities.Since the 1971 San Fernando earthquake,there has been a better understanding of the seismic performance of bridges.Nonetheless,there are no detailed guidelines addressing the performance of skewed highway bridges.Several parameters affect the response of skewed highway bridges under both service and seismic loads which makes their behavior complex.Therefore,there is a need for more research to study the effect of skew angle and other related factors on the performance of highway bridges.This paper examines the seismic performance of a three-span continuous concrete box girder bridge with skew angles from 0 to 60 degrees,analytically.Finite element (FE) and simplified beam-stick (BS) models of the bridge were developed using SAP2000.Different types of analysis were considered on both models such as:nonlinear static pushover,and linear and nonlinear time history analyses.A comparison was conducted between FE and BS,different skew angles,abutment support conditions,and time history and pushover analysis.It is shown that the BS model has the capability to capture the coupling due to skew and the significant modes for moderate skew angles.Boundary conditions and pushover load profile are determined to have a major effect on pushover analysis.Pushover analysis may be used to predict the maximum deformation and hinge formation adequately.

  20. Utility functions predict variance and skewness risk preferences in monkeys.

    Science.gov (United States)

    Genest, Wilfried; Stauffer, William R; Schultz, Wolfram

    2016-07-26

    Utility is the fundamental variable thought to underlie economic choices. In particular, utility functions are believed to reflect preferences toward risk, a key decision variable in many real-life situations. To assess the validity of utility representations, it is therefore important to examine risk preferences. In turn, this approach requires formal definitions of risk. A standard approach is to focus on the variance of reward distributions (variance-risk). In this study, we also examined a form of risk related to the skewness of reward distributions (skewness-risk). Thus, we tested the extent to which empirically derived utility functions predicted preferences for variance-risk and skewness-risk in macaques. The expected utilities calculated for various symmetrical and skewed gambles served to define formally the direction of stochastic dominance between gambles. In direct choices, the animals' preferences followed both second-order (variance) and third-order (skewness) stochastic dominance. Specifically, for gambles with different variance but identical expected values (EVs), the monkeys preferred high-variance gambles at low EVs and low-variance gambles at high EVs; in gambles with different skewness but identical EVs and variances, the animals preferred positively over symmetrical and negatively skewed gambles in a strongly transitive fashion. Thus, the utility functions predicted the animals' preferences for variance-risk and skewness-risk. Using these well-defined forms of risk, this study shows that monkeys' choices conform to the internal reward valuations suggested by their utility functions. This result implies a representation of utility in monkeys that accounts for both variance-risk and skewness-risk preferences.

  1. On the bilinear structure associated to the skew Bezoutian

    CERN Document Server

    Jouve, Florent

    2010-01-01

    Let (p,q) be a couple of reciprocal (resp. q is reciprocal and p is skew-reciprocal) coprime polynomials of degree d over a field with characteristic not 2.To such a couple we can associate a non-singular antisymmetric (resp. symmetric) matrix of size d, which we call the skew Bezoutian. In this paper we study some properties of the corresponding symplectic (resp. quadratic) space. Using the skew Bezoutian we construct explicit isometries of bilinear spaces with given invariants (such as the characteristic polynomial or Jordan form and, in the quadratic case, the spinor norm).

  2. Differences of Skew Schur Functions of Staircases with Transposed Foundations

    CERN Document Server

    Morin, Matthew

    2010-01-01

    We consider the skew diagram $\\Delta_n$, which is the $180^\\circ$ rotation of the staircase diagram $\\delta_n = (n,n-1,n-2,...,2,1)$. We create a staircase with bad foundation by augmenting $\\Delta_n$ with another skew diagram, which we call the \\textit{foundation}. We consider pairs of staircases with bad foundation whose foundations are transposes of one another. Among these pairs, we show that the difference of the corresponding skew Schur functions is Schur-positive in the case when one of the foundations consists of either a one or two row diagram, or a hook diagram.

  3. Delivering Left-Skewed Portfolio Payoff Distributions in the Presence of Transaction Costs

    Directory of Open Access Journals (Sweden)

    Jacek B Krawczyk

    2015-08-01

    Full Text Available For pension-savers, a low payoff is a financial disaster. Such investors will most likely prefer left-skewed payoff distributions over right-skewed payoff distributions. We explore how such distributions can be delivered. Cautious-relaxed utility measures are cautious in ensuring that payoffs don’t fall much below a reference value, but relaxed about exceeding it. We find that the payoff distribution delivered by a cautious-relaxed utility measure has appealing features which payoff distributions delivered by traditional utility functions don’t. In particular, cautious-relaxed distributions can have the mass concentrated on the left, hence be left-skewed. However, cautious-relaxed strategies prescribe frequent portfolio adjustments which may be expensive if transaction costs are charged. In contrast, more traditional strategies can be time-invariant. Thus we investigate the impact of transaction costs on the appeal of cautious-relaxed strategies. We find that relatively high transaction fees are required for the cautious-relaxed strategy to lose its appeal. This paper contributes to the literature which compares utility measures by the payoff distributions they produce and finds that a cautious-relaxed utility measure will deliver payoffs that many investors will prefer.

  4. Patterns of paternity skew among polyandrous social insects

    DEFF Research Database (Denmark)

    Jaffé, Rodolfo; Garcia-Gonzalez, Francisco; den Boer, Susanne;

    2012-01-01

    Monogamy results in high genetic relatedness among offspring and thus it is generally assumed to be favored by kin selection. Female multiple mating (polyandry) has nevertheless evolved several times in the social Hymenoptera (ants, bees, and wasps), and a substantial amount of work has been...... conducted to understand its costs and benefits. Relatedness and inclusive fitness benefits are, however, not only influenced by queen mating frequency but also by paternity skew, which is a quantitative measure of paternity biases among the offspring of polyandrous females. We performed a large......-scale phylogenetic analysis of paternity skew across polyandrous social Hymenoptera. We found a general and significant negative association between paternity frequency and paternity skew. High paternity skew, which increases relatedness among colony members and thus maximizes inclusive fitness gains, characterized...

  5. Systems of Differential Equations with Skew-Symmetric, Orthogonal Matrices

    Science.gov (United States)

    Glaister, P.

    2008-01-01

    The solution of a system of linear, inhomogeneous differential equations is discussed. The particular class considered is where the coefficient matrix is skew-symmetric and orthogonal, and where the forcing terms are sinusoidal. More general matrices are also considered.

  6. Although Relatively Few, "Doctor Shoppers" Skew Opioid Prescribing

    Science.gov (United States)

    ... Opioid Prescribing Although Relatively Few, “Doctor Shoppers” Skew Opioid Prescribing Email Facebook Twitter May 27, 2014 One ... patterns and alert both physicians and pharmacies. Extreme Opioid Purchasers Figure 1. Prescriber Utilization Distinguishes Likely “Doctor ...

  7. Systems of Differential Equations with Skew-Symmetric, Orthogonal Matrices

    Science.gov (United States)

    Glaister, P.

    2008-01-01

    The solution of a system of linear, inhomogeneous differential equations is discussed. The particular class considered is where the coefficient matrix is skew-symmetric and orthogonal, and where the forcing terms are sinusoidal. More general matrices are also considered.

  8. Sickle Cell Trait in Blacks Can Skew Diabetes Test Results

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_163463.html Sickle Cell Trait in Blacks Can Skew Diabetes Test Results ... less accurate in black people who have the sickle cell anemia trait, a new study says. The test ...

  9. PRINCIPLE OF SKEW QUADRUPOLE MODULATION TO MEASURE BETATRON COUPLING.

    Energy Technology Data Exchange (ETDEWEB)

    LUO.Y.PILAT,F.ROSER,T.ET AL.

    2004-07-05

    The measurement of the residual betatron coupling via skew quadrupole modulation is a new diagnostics technique that has been developed and tested at the Relativistic Heavy Ion Collider (RHIC) as a very promising method for the linear decoupling on the ramp. By modulating the strengths of different skew quadrupole families the two eigentunes are precisely measured with the phase lock loop system. The projections of the residual coupling coefficient onto the skew quadrupole coupling modulation directions are determined. The residual linear coupling could be corrected according to the measurement. An analytical solution for skew quadrupole modulation based on Hamiltonian perturbation approximation is given, and simulation code using smooth accelerator model is also developed. Some issues concerning the practical applications of this technique are discussed.

  10. Maximal supports and Schur-positivity among connected skew shapes

    CERN Document Server

    McNamara, Peter R W

    2011-01-01

    The Schur-positivity order on skew shapes is defined by B \\leq A if the difference s_A - s_B is Schur-positive. It is an open problem to determine those connected skew shapes that are maximal with respect to this ordering. A strong sufficient condition for the Schur-positivity of s_A - s_B is that the support of B is contained in that of A, where the support of B is defined to be the set of partitions lambda for which s_lambda appears in the Schur expansion of s_B. We show that to determine the maximal connected skew shapes in the Schur-positivity order and this support containment order, it suffices to consider a special class of ribbon shapes. We explicitly determine the support for these ribbon shapes, thereby determining the maximal connected skew shapes in the support containment order.

  11. The affective impact of financial skewness on neural activity and choice.

    Science.gov (United States)

    Wu, Charlene C; Bossaerts, Peter; Knutson, Brian

    2011-02-15

    Few finance theories consider the influence of "skewness" (or large and asymmetric but unlikely outcomes) on financial choice. We investigated the impact of skewed gambles on subjects' neural activity, self-reported affective responses, and subsequent preferences using functional magnetic resonance imaging (FMRI). Neurally, skewed gambles elicited more anterior insula activation than symmetric gambles equated for expected value and variance, and positively skewed gambles also specifically elicited more nucleus accumbens (NAcc) activation than negatively skewed gambles. Affectively, positively skewed gambles elicited more positive arousal and negatively skewed gambles elicited more negative arousal than symmetric gambles equated for expected value and variance. Subjects also preferred positively skewed gambles more, but negatively skewed gambles less than symmetric gambles of equal expected value. Individual differences in both NAcc activity and positive arousal predicted preferences for positively skewed gambles. These findings support an anticipatory affect account in which statistical properties of gambles--including skewness--can influence neural activity, affective responses, and ultimately, choice.

  12. Skewed X inactivation in Lesch-Nyhan disease carrier females.

    Science.gov (United States)

    Torres, Rosa J; Puig, Juan G

    2017-09-14

    X chromosome inactivation (XCI) ratios of normal females can range from a highly skewed ratio of 0:100 to a 50:50 ratio. In several X-linked disorders, female carriers present skewed X inactivation. Hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency is an X-linked disorder. Males are affected and present with the complete Lesch-Nyhan disease (LND) or with a partial phenotype (Lesch-Nyhan variant, LNV). Female carriers are usually asymptomatic. The aim of the present study was to analyze the XCI pattern of HPRT-deficiency carrier females. As a group, 75% of HPRT-deficiency carrier females presented skewed XCI. Moreover, skewed XCI is significantly more frequent in LND carriers (83%) than in LNV (0-50%, depending on the phenotype severity). The ratios of the preferentially inactivated allele of carrier females were significantly higher than the ratios of the preferentially inactivated allele of noncarrier females (89.4±15, n=52 vs 65.2±12, n=52; P<0.0001). For carrier diagnosis, the presence of skewed XCI presents a sensitivity of 75% with a specificity of 85%. In LND families, the presence of skewed XCI is more sensitive for carrier diagnosis than in LNV families; however, we believe that this test is not accurate for carrier diagnostic purposes.Journal of Human Genetics advance online publication, 14 September 2017; doi:10.1038/jhg.2017.88.

  13. Statistics on cannabis users skew perceptions of cannabis use

    Directory of Open Access Journals (Sweden)

    Rachel Melissa Burns

    2013-11-01

    Full Text Available Collecting information about the prevalence of cannabis use is necessary but not sufficient for understanding the size, dynamics, and outcomes associated with cannabis markets. This paper uses two data sets describing cannabis consumption in the United States and Europe to highlight 1 differences in inferences about sub-populations based on the measure used to quantify cannabis-related activity; 2 how different measures of cannabis-related activity can be used to more accurately describe trends in cannabis usage over time; and 3 the correlation between frequency of use in the past month and average grams consumed per day. Key findings: Focusing on days of use instead of prevalence shows substantially greater increases in U.S. cannabis use in recent years; however, the recent increase is mostly among adults, not youth. Relatively more rapid growth in use days also occurred among the college-educated and Hispanic. Further, data from a survey conducted in several European countries show a strong positive correlation between frequency of use and quantity consumed per day of use, suggesting consumption is even more skewed toward the minority of heavy users than is suggested by days-of-use calculations.

  14. Remaining useful life prediction for an adaptive skew-Wiener process model

    Science.gov (United States)

    Huang, Zeyi; Xu, Zhengguo; Ke, Xiaojie; Wang, Wenhai; Sun, Youxian

    2017-03-01

    Predicting the remaining useful life for operational devices plays a critical role in prognostics and health management. As the models based on the stochastic processes are widely used for characterizing the degradation trajectory, an adaptive skew-Wiener model, which is much more flexible than traditional stochastic process models, is proposed to model the degradation drift of industrial devices. To make full use of the prior knowledge and the historical information, an on-line filtering algorithm is proposed for state estimation, a two-stage algorithm is adopted to estimate unknown parameters as well. For remaining useful life prediction, a novel result is presented with an explicit form based on the closed skew normal distribution. Finally, sufficient Monte Carlo simulations and an application for ball bearings in rotating electrical machines are used to validate our approach.

  15. Coil Creep and Skew-Quadrupole Field Components in the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Annala, G.; Harding, D.J.; Syphers, M.J.; /Fermilab

    2011-07-11

    During the start-up of Run II of the Tevatron Collider program, several issues surfaced which were not present, or not seen as detrimental, during Run I. These included the repeated deterioration of the closed orbit requiring orbit smoothing every two weeks or so, the inability to correct the closed orbit to desired positions due to various correctors running at maximum limits, regions of systematically strong vertical dipole corrections, and the identification of very strong coupling between the two transverse degrees-of-freedom. It became apparent that many of the problems being experienced operationally were connected to a deterioration of the main dipole magnet alignment, and remedial actions were undertaken. However, the alignment alone was not enough to explain the corrector strengths required to handle transverse coupling. With one exception, strong coupling had generally not been an issue in the Tevatron during Run I. Based on experience with the Main Ring, the Tevatron was designed with a very strong skew quadrupole circuit to compensate any quadrupole alignment and skew quadrupole field errors that might present themselves. The circuit was composed of 48 correctors placed evenly throughout the arcs, 8 per sector, evenly placed in every other cell. Other smaller circuits were installed but not initially needed or commissioned. These smaller circuits were composed of individual skew quadrupole correctors on either side of the long straight sections. These circuits were tuned by first bringing the horizontal and vertical tunes near each other. The skew quadrupoles were then adjusted to minimize tune split, usually to less than 0.003. Initially, the main skew quad circuit (designated T:SQ) could accomplish this global decoupling with only 4% of its possible current, and the smaller circuits were not required at all. The start-up of Run Ib was complicated by what was later discovered to be a rolled triplet quadrupole magnet in one of the Interaction Regions

  16. Asymptotic Distribution of Coefficients of Skewness and Kurtosis

    Directory of Open Access Journals (Sweden)

    Narges Abbasi

    2009-01-01

    Full Text Available Problem statement: In literature, a classic method which has been used to recognize the distribution so far is the measurement of its skewedness and kurtosis. However, there remains a question: how would these measurements work for skewed normal distribution when the size of the sample is large? Approach: This research aimed to determine the asymptotic distribution of skewedness and kurtosis measures in skewed normal distribution. In conducting this research, two groups of inferential findings will help. First, skewed normal distribution which has already been studied by a lot of researchers and we apply its characteristics. Second, there is the U-statistics theory which guides us to the determining of asymptotic distribution measures for skewedness and kurtosis. The combination of these two will solve the problem of this study. Results: Asymptotic distribution of measures for skewdness and kurtosis falls in the normal families. With the size of large samples, the values of expectation of these measures are also determined. By letting zero for skewedness parameter, asymptotic distribution for normal distribution can also be obtained. Conclusion: The findings of this study show new characteristics for skew normal distribution and this results in a new way for skew normal distribution recognition.

  17. On river-floodplain interaction and hydrograph skewness

    Science.gov (United States)

    Fleischmann, Ayan S.; Paiva, Rodrigo C. D.; Collischonn, Walter; Sorribas, Mino V.; Pontes, Paulo R. M.

    2016-10-01

    Understanding hydrological processes occurring within a basin by looking at its outlet hydrograph can improve and foster comprehension of ungauged regions. In this context, we present an extensive examination of the roles that floodplains play on driving hydrograph shapes. Observations of many river hydrographs with large floodplain influence are carried out and indicate that a negative skewness of the hydrographs is present among many of them. Through a series of numerical experiments and analytical reasoning, we show how the relationship between flood wave celerity and discharge in such systems is responsible for determining the hydrograph shapes. The more water inundates the floodplains upstream of the observed point, the more negatively skewed is the observed hydrograph. A case study is performed in the Amazon River Basin, where major rivers with large floodplain attenuation (e.g., Purus, Madeira, and Juruá) are identified with higher negative skewness in the respective hydrographs. Finally, different wetland types could be distinguished by using this feature, e.g., wetlands maintained by endogenous processes, from wetlands governed by overbank flow (along river floodplains). A metric of hydrograph skewness was developed to quantify this effect, based on the time derivative of discharge. Together with the skewness concept, it may be used in other studies concerning the relevance of floodplain attenuation in large, ungauged rivers, where remote sensing data (e.g., satellite altimetry) can be very useful.

  18. 76 FR 72242 - Proposed Information Collection (Survey of Post-Deployment Adjustment Among OEF and OIF Veterans...

    Science.gov (United States)

    2011-11-22

    ... Form 10-21089 will be used to access health conditions, occupational, family and social adjustment and...: November 17, 2011. By direction of the Secretary. Denise McLamb, Program Analyst, Enterprise...

  19. Isomorphic Operators and Functional Equations for the Skew-Circulant Algebra

    Directory of Open Access Journals (Sweden)

    Zhaolin Jiang

    2014-01-01

    Full Text Available The skew-circulant matrix has been used in solving ordinary differential equations. We prove that the set of skew-circulants with complex entries has an idempotent basis. On that basis, a skew-cyclic group of automorphisms and functional equations on the skew-circulant algebra is introduced. And different operators on linear vector space that are isomorphic to the algebra of n×n complex skew-circulant matrices are displayed in this paper.

  20. ADJUSTMENT FACTORS AND ADJUSTMENT STRUCTURE

    Institute of Scientific and Technical Information of China (English)

    Tao Benzao

    2003-01-01

    In this paper, adjustment factors J and R put forward by professor Zhou Jiangwen are introduced and the nature of the adjustment factors and their role in evaluating adjustment structure is discussed and proved.

  1. Skew Schur Functions of Sums of Fat Staircases

    CERN Document Server

    Morin, Matthew

    2010-01-01

    We define a fat staircase to be a Ferrers diagram corresponding to a partition of the form $(n^{\\alpha_n}, {n-1}^{\\alpha_{n-1}},..., 1^{\\alpha_1})$, where $\\alpha = (\\alpha_1,...,\\alpha_n)$ is a composition, or the $180^\\circ$ rotation of such a diagram. If a diagram's skew Schur function is a linear combination of Schur functions of fat staircases, we call the diagram a sum of fat staircases. We prove a Schur-positivity result that is obtained each time we augment a sum of fat staircases with a skew diagram. We also determine conditions on which diagrams can be sums of fat staircases, including necessary and sufficient conditions in the special case when the diagram is a fat staircase skew a single row or column.

  2. Adjunctions between Boolean spaces and skew Boolean algebras

    CERN Document Server

    Kudryavtseva, Ganna

    2011-01-01

    We apply the representation theory of left-handed skew Boolean algebras by sections of their dual \\'{e}tale spaces, given in \\cite{K}, to construct a series of dual adjunctions between the categories of locally compact Boolean spaces and left-handed skew Boolean algebras by means of extensions of certain enriched $\\Hom$-set functors induced by objects sitting in two categories. The constructed adjunctions are "deformations" of Stone duality obtained by the replacement in the latter of the category of Boolean algebras by the category of left-handed skew Boolean algebras. The constructions provide natural settings for the $\\omega$-functor constructed in \\cite{LS} and its left adjoint functor.

  3. Speckles generated by skewed, short-coherence light beams

    CERN Document Server

    Brogioli, D; Croccolo, F; Ziano, R; Mantegazza, F

    2011-01-01

    When a coherent laser beam impinges on a random sample (e.g. a colloidal suspension), the scattered light exhibits characteristic speckles. If the temporal coherence of the light source is too short, then the speckles disappear, along with the possibility of performing homodyne or heterodyne scattering detection or photon correlation spectroscopy. Here we investigate the scattering of a so-called "skewed coherence beam", i.e., a short-coherence beam modified such that the field is coherent within slabs that are skewed with respect to the wave fronts. We show that such a beam generates speckles and can be used for heterodyne scattering detection, despite its short temporal coherence. When applied to quite turbid samples, the technique has the remarkable advantage of suppressing the multiple scattering contribution of the scattering signal. The phenomenon presented here represents a very effective method for measuring the coherence skewness of either a continuous wave or a pulsed beam. Another field of applicat...

  4. Performance Analyses of IDEAL Algorithm on Highly Skewed Grid System

    Directory of Open Access Journals (Sweden)

    Dongliang Sun

    2014-03-01

    Full Text Available IDEAL is an efficient segregated algorithm for the fluid flow and heat transfer problems. This algorithm has now been extended to the 3D nonorthogonal curvilinear coordinates. Highly skewed grids in the nonorthogonal curvilinear coordinates can decrease the convergence rate and deteriorate the calculating stability. In this study, the feasibility of the IDEAL algorithm on highly skewed grid system is analyzed by investigating the lid-driven flow in the inclined cavity. It can be concluded that the IDEAL algorithm is more robust and more efficient than the traditional SIMPLER algorithm, especially for the highly skewed and fine grid system. For example, at θ = 5° and grid number = 70 × 70 × 70, the convergence rate of the IDEAL algorithm is 6.3 times faster than that of the SIMPLER algorithm, and the IDEAL algorithm can converge almost at any time step multiple.

  5. Uniqueness: skews bit occurrence frequencies in randomly generated fingerprint libraries.

    Science.gov (United States)

    Chen, Nelson G

    2016-08-01

    Requiring that randomly generated chemical fingerprint libraries have unique fingerprints such that no two fingerprints are identical causes a systematic skew in bit occurrence frequencies, the proportion at which specified bits are set. Observed frequencies (O) at which each bit is set within the resulting libraries systematically differ from frequencies at which bits are set at fingerprint generation (E). Observed frequencies systematically skew toward 0.5, with the effect being more pronounced as library size approaches the compound space, which is the total number of unique possible fingerprints given the number of bit positions each fingerprint contains. The effect is quantified for varying library sizes as a fraction of the overall compound space, and for changes in the specified frequency E. The cause and implications for this systematic skew are subsequently discussed. When generating random libraries of chemical fingerprints, the imposition of a uniqueness requirement should either be avoided or taken into account.

  6. Determining collective barrier operation skew in a parallel computer

    Energy Technology Data Exchange (ETDEWEB)

    Faraj, Daniel A.

    2015-11-24

    Determining collective barrier operation skew in a parallel computer that includes a number of compute nodes organized into an operational group includes: for each of the nodes until each node has been selected as a delayed node: selecting one of the nodes as a delayed node; entering, by each node other than the delayed node, a collective barrier operation; entering, after a delay by the delayed node, the collective barrier operation; receiving an exit signal from a root of the collective barrier operation; and measuring, for the delayed node, a barrier completion time. The barrier operation skew is calculated by: identifying, from the compute nodes' barrier completion times, a maximum barrier completion time and a minimum barrier completion time and calculating the barrier operation skew as the difference of the maximum and the minimum barrier completion time.

  7. Convexity Adjustments

    DEFF Research Database (Denmark)

    M. Gaspar, Raquel; Murgoci, Agatha

    2010-01-01

    of particular importance to practitioners: yield convexity adjustments, forward versus futures convexity adjustments, timing and quanto convexity adjustments. We claim that the appropriate way to look into any of these adjustments is as a side effect of a measure change, as proposed by Pelsser (2003...

  8. Effect of Phase Response Curve Skew on Synchronization with and without Conduction Delays

    Directory of Open Access Journals (Sweden)

    Carmen eCanavier

    2013-12-01

    Full Text Available A central problem in cortical processing including sensory binding and attentional gating is how neurons can synchronize their responses with zero or near-zero time lag. For a spontaneously firing neuron, an input from another neuron can delay or advance the next spike by different amounts depending upon the timing of the input relative to the previous spike. This information constitutes the phase response curve (PRC. We present a simple graphical method for determining the effect of PRC shape on synchronization tendencies and illustrate it using type 1 PRCs, which consist entirely of advances (delays in response to excitation (inhibition. We obtained the following generic solutions for type 1 PRCs, which include the pulse coupled leaky integrate and fire model. For pairs with mutual excitation, exact synchrony can be stable for strong coupling because of the stabilizing effect of the causal limit region of the PRC in which an input triggers a spike immediately upon arrival. However, synchrony is unstable for short delays, because delayed inputs arrive during a refractory period and cannot trigger an immediate spike. Right skew destabilizes antiphase and enables modes with time lags that grow as the conduction delay is increased. Therefore, right skew favors near-synchrony at short conduction delays and a gradual transition between synchrony and antiphase for pairs coupled by mutual excitation. For pairs with mutual inhibition, zero time lag synchrony is stable for conduction delays ranging from zero to a substantial fraction of the period for pairs. However, for right skew there is a preferred antiphase mode at short delays. In contrast to mutual excitation, left skew destabilizes antiphase for mutual inhibition so that synchrony dominates at short delays as well. These pairwise synchronization tendencies constrain the synchronization properties of neurons embedded in larger networks.

  9. Market skewness risk and the cross section of stock returns

    DEFF Research Database (Denmark)

    Chang, B.Y.; Christoffersen, Peter; Jacobs, K.

    2013-01-01

    The cross section of stock returns has substantial exposure to risk captured by higher moments of market returns. We estimate these moments from daily Standard & Poor's 500 index option data. The resulting time series of factors are genuinely conditional and forward-looking. Stocks with high...... exposure to innovations in implied market skewness exhibit low returns on average. The results are robust to various permutations of the empirical setup. The market skewness risk premium is statistically and economically significant and cannot be explained by other common risk factors such as the market...... excess return or the size, book-to-market, momentum, and market volatility factors, or by firm characteristics....

  10. Strong skew commutativity preserving maps on von Neumann algebras

    CERN Document Server

    Qi, Xiaofei

    2012-01-01

    Let ${\\mathcal M}$ be a von Neumann algebra without central summands of type $I_1$. Assume that $\\Phi:{\\mathcal M}\\rightarrow {\\mathcal M}$ is a surjective map. It is shown that $\\Phi$ is strong skew commutativity preserving (that is, satisfies $\\Phi(A)\\Phi(B)-\\Phi(B)\\Phi(A)^*=AB-BA^*$ for all $A,B\\in{\\mathcal M}$) if and only if there exists some self-adjoint element $Z$ in the center of ${\\mathcal M}$ with $Z^2=I$ such that $\\Phi(A)=ZA$ for all $A\\in{\\mathcal M}$. The strong skew commutativity preserving maps on prime involution rings and prime involution algebras are also characterized.

  11. Mixtures of Common Skew-t Factor Analyzers

    OpenAIRE

    Murray, Paula M.; McNicholas, Paul D.; Browne, Ryan P.

    2013-01-01

    A mixture of common skew-t factor analyzers model is introduced for model-based clustering of high-dimensional data. By assuming common component factor loadings, this model allows clustering to be performed in the presence of a large number of mixture components or when the number of dimensions is too large to be well-modelled by the mixtures of factor analyzers model or a variant thereof. Furthermore, assuming that the component densities follow a skew-t distribution allows robust clusterin...

  12. Parameterizing unconditional skewness in models for financial time series

    DEFF Research Database (Denmark)

    He, Changli; Silvennoinen, Annastiina; Teräsvirta, Timo

    In this paper we consider the third-moment structure of a class of time series models. It is often argued that the marginal distribution of financial time series such as returns is skewed. Therefore it is of importance to know what properties a model should possess if it is to accommodate...... unconditional skewness. We consider modelling the unconditional mean and variance using models that respond nonlinearly or asymmetrically to shocks. We investigate the implications of these models on the third-moment structure of the marginal distribution as well as conditions under which the unconditional...

  13. Skew-orthogonal polynomials, differential systems and random matrix theory

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Saugata [Abdus Salam ICTP, Strada Costiera 11, 34100, Trieste (Italy)

    2007-01-26

    We study skew-orthogonal polynomials with respect to the weight function exp [ - 2V(x)], with V(x) = {sigma}{sup 2d}{sub K=1}(u{sub K}/K)x{sup K}, u{sub 2d} > 0, d > 0. A finite subsequence of such skew-orthogonal polynomials arising in the study of orthogonal and symplectic ensembles of random matrices satisfies a system of differential-difference-deformation equation. The vectors formed by such subsequence have the rank equal to the degree of the potential in the quaternion sense. These solutions satisfy certain compatibility condition and hence admit a simultaneous fundamental system of solutions.

  14. Skew category algebras associated with partially defined dynamical systems

    DEFF Research Database (Denmark)

    Lundström, Patrik; Öinert, Per Johan

    2012-01-01

    We introduce partially defined dynamical systems defined on a topological space. To each such system we associate a functor s from a category G to Topop and show that it defines what we call a skew category algebra A ⋊σ G. We study the connection between topological freeness of s and, on the one...

  15. An Identity with Skew Derivations on Lie Ideals

    Institute of Scientific and Technical Information of China (English)

    Wang Zheng-ping; Rehman Ur Nadeem; Huang Shu-liang

    2016-01-01

    Let R be a 2-torsion free prime ring and L a noncommutative Lie ideal of R. Suppose that (d,σ) is a skew derivation of R such that xsd(x)xt = 0 for all x∈L, where s, t are fixed non-negative integers. Then d=0.

  16. Modelling psychiatric measures using Skew-Normal distributions

    Science.gov (United States)

    Counsell, N.; Cortina-Borja, M.; Lehtonen, A.; Stein, A.

    2011-01-01

    Data from psychiatric research frequently exhibit departures from Normality. Methods which utilise the data optimally to model the distribution directly are available. We highlight the issue of modelling skewness, resulting from screening instruments where the majority of respondents are healthy individuals and few participants have a value reflecting particular disorders. PMID:21036551

  17. Conglomerate investment, skewness, and the CEO long shot bias

    NARCIS (Netherlands)

    Schneider, C.A.R.; Spalt, Oliver

    2016-01-01

    Do behavioral biases of executives matter for corporate investment decisions? Using segment-level capital allocation in multi-segment firms ("conglomerates") as a laboratory, we show that capital expenditure is increasing in the expected skewness of segment returns. Conglomerates invest more in high

  18. Asymmetric skew Bessel processes and their applications to finance

    NARCIS (Netherlands)

    Decamps, M.; Goovaerts, M.J.; Schoutens, W.

    2006-01-01

    In this paper, we extend the Harrison and Shepp's construction of the skew Brownian motion (1981) and we obtain a diffusion similar to the two-dimensional Bessel process with speed and scale densities discontinuous at one point. Natural generalizations to multi-dimensional and fractional order

  19. Conglomerate investment, skewness, and the CEO long shot bias

    NARCIS (Netherlands)

    Schneider, C.A.R.; Spalt, Oliver

    2016-01-01

    Do behavioral biases of executives matter for corporate investment decisions? Using segment-level capital allocation in multi-segment firms ("conglomerates") as a laboratory, we show that capital expenditure is increasing in the expected skewness of segment returns. Conglomerates invest more in

  20. Large deflection analysis of skew plates under uniformly distributed ...

    African Journals Online (AJOL)

    user

    load-deflection plane to show the effect of skew angle, aspect ratio and boundary condition. ... by edge 1, 2, 3 and 4 on the plate boundaries in Figures 1(a)-1(d). ... one-dimensional coordinate functions along normalized coordinate are shown ...

  1. Parameterizing unconditional skewness in models for financial time series

    DEFF Research Database (Denmark)

    He, Changli; Silvennoinen, Annastiina; Teräsvirta, Timo

    In this paper we consider the third-moment structure of a class of time series models. It is often argued that the marginal distribution of financial time series such as returns is skewed. Therefore it is of importance to know what properties a model should possess if it is to accommodate...

  2. Generating monthly rainfall amount using multivariate skew-t copula

    Science.gov (United States)

    Radi, Noor Fadhilah Ahmad; Zakaria, Roslinazairimah; Zanariah Satari, Siti

    2017-09-01

    This study aims to generate rainfall data in cases where the data is not available or not enough for a certain area of study. In general, the rainfall data is rightly skewed, so the multivariate skew-t copula is used as it able to model rainfall amount and capture the spatial dependence in the data. To illustrate the methodology, three rainfall stations in Kelantan are used. Firstly, the observed data is transformed to uniform unit. The Spearman’s correlation coefficient is calculated between the three stations. It is found that the correlations between the stations are significance at α = 0.05. The next step involved generating the synthetic rainfall data using the multivariate skew-t copula. The data is then transformed to uniform unit and the correlation coefficient is calculated for the generated data. Finally, the correlation coefficient of the observed and the generated data are compared. The Kolmogorov-Smirnov goodness of fit test is used to assess the fit between theoretical and empirical copula and supported by graphical representation. The results show that there is no significant difference between empirical and theoretical copula at 5% significance level. Thus, the multivariate skew-t copula is suitable to generate synthetic rainfall data that can mimic the observed rainfall data. It can also be used to present different rainfall scenarios by changing the value of the parameters in the model.

  3. On Optimal Backward Perturbation Analysis for the Linear System with Skew Circulant Coefficient Matrix

    Science.gov (United States)

    Jiang, Zhaolin; Shen, Nuo; Zhou, Jianwei

    2013-01-01

    We first give the style spectral decomposition of a special skew circulant matrix C and then get the style decomposition of arbitrary skew circulant matrix by making use of the Kronecker products between the elements of first row in skew circulant and the special skew circulant C. Besides that, we obtain the singular value of skew circulant matrix as well. Finally, we deal with the optimal backward perturbation analysis for the linear system with skew circulant coefficient matrix on the base of its style spectral decomposition. PMID:24369488

  4. Root waving and skewing - unexpectedly in micro-g

    Directory of Open Access Journals (Sweden)

    Roux Stanley J

    2012-12-01

    Full Text Available Abstract Gravity has major effects on both the form and overall length of root growth. Numerous papers have documented these effects (over 300 publications in the last 5 years, the most well-studied being gravitropism, which is a growth re-orientation directed by gravity toward the earth’s center. Less studied effects of gravity are undulations due to the regular periodic change in the direction root tips grow, called waving, and the slanted angle of growth roots exhibit when they are growing along a nearly-vertical surface, called skewing. Although diverse studies have led to the conclusion that a gravity stimulus is needed for plant roots to show waving and skewing, the novel results just published by Paul et al. (2012 reveal that this conclusion is not correct. In studies carried out in microgravity on the International Space Station, the authors used a new imaging system to collect digital photographs of plants every six hours during 15 days of spaceflight. The imaging system allowed them to observe how roots grew when their orientation was directed not by gravity but by overhead LED lights, which roots grew away from because they are negatively phototropic. Surprisingly, the authors observed both skewing and waving in spaceflight plants, thus demonstrating that both growth phenomena were gravity independent. Touch responses and differential auxin transport would be common features of root waving and skewing at 1-g and micro-g, and the novel results of Paul et al. will focus the attention of cell and molecular biologists more on these features as they try to decipher the signaling pathways that regulate root skewing and waving.

  5. Prototyping and Characterization of an Adjustable Skew Angle Single Gimbal Control Moment Gyroscope

    Science.gov (United States)

    2015-03-01

    off switch for safe installation and removal of the battery pack and connectors for standard banana plugs. The battery and block are shown in Figure 22... shell (SSH) connection over the campus Wi-Fi network. A copy of the Python code was resident on both the laptop and the BBB. The local laptop Python code...rotated to show the switch mounting location on the right, the separated conduits for the positive and negative battery leads, the banana connector

  6. An 8-bit 100-MS/s digital-to-skew converter embedded switch with a 200-ps range for time-interleaved sampling

    Institute of Scientific and Technical Information of China (English)

    Zhu Xiaoshi; Chen Chixiao; Xu Jialiang; Ye Fan; Ren Junyan

    2013-01-01

    A sampling switch with an embedded digital-to-skew converter (DSC) is presented.The proposed switch eliminates time-interleaved ADCs' skews by adjusting the boosted voltage.A similar bridged capacitors' charge sharing structure is used to minimize the area.The circuit is fabricated in a 0.18μm CMOS process and achieves sub-1 ps resolution and 200 ps timing range at a rate of 100 MS/s.The power consumption is 430 μW at maximum.The measurement result also includes a 2-channel 14-bit 100 MS/s time-interleaved ADCs (TI-ADCs) with the proposed DSC switch's demonstration.This scheme is widely applicable for the clock skew and aperture error calibration demanded in TI-ADCs and SHA-less ADCs.

  7. Heteroscedastic nonlinear regression models based on scale mixtures of skew-normal distributions.

    Science.gov (United States)

    Lachos, Victor H; Bandyopadhyay, Dipankar; Garay, Aldo M

    2011-08-01

    An extension of some standard likelihood based procedures to heteroscedastic nonlinear regression models under scale mixtures of skew-normal (SMSN) distributions is developed. We derive a simple EM-type algorithm for iteratively computing maximum likelihood (ML) estimates and the observed information matrix is derived analytically. Simulation studies demonstrate the robustness of this flexible class against outlying and influential observations, as well as nice asymptotic properties of the proposed EM-type ML estimates. Finally, the methodology is illustrated using an ultrasonic calibration data.

  8. Present-day zonal wind influences projected Indian Ocean Dipole skewness

    Science.gov (United States)

    Ng, Benjamin; Cai, Wenju

    2016-11-01

    A prominent feature of the Indian Ocean Dipole (IOD) is its positive skewness, where positive phases tend to be stronger in amplitude than the negative phase. Positive IOD events are associated with devastating floods over parts of East Africa and India, while Australia and Indonesia experience dry conditions. Under greenhouse warming, climate models project a weakening of the positive IOD skewness, but their simulation of present-day skewness is too weak. Here we show that this bias and the projected skewness change are related to the simulation of the climatological zonal wind in the central equatorial Indian Ocean. In particular, models with overly weak present-day westerlies, which is a common model bias, generate overly weak present-day skewness and a smaller projected reduction in skewness. Improving the ability of models in simulating stronger westerly winds may lead to stronger present-day simulated skewness and a larger skewness reduction in a warmer climate.

  9. Joint IQ Skew and Chromatic Dispersion Estimation for Coherent Optical Communication Receivers

    DEFF Research Database (Denmark)

    Medeiros Diniz, Júlio César; Porto da Silva, Edson; Piels, Molly

    2016-01-01

    A low-complexity scanning method for joint estimation of receiver IQ skew and chromatic dispersion is proposed. This method shows less than 1 ps skew error for a 1200-km 32-GBd DP-16QAM optical transmission experiment.......A low-complexity scanning method for joint estimation of receiver IQ skew and chromatic dispersion is proposed. This method shows less than 1 ps skew error for a 1200-km 32-GBd DP-16QAM optical transmission experiment....

  10. Technological Inefficiency and the Skewness of the Error Component in Stochastic Frontier Analysis

    NARCIS (Netherlands)

    M.A. Carree (Martin)

    2002-01-01

    textabstractThis paper concentrates on negatively skewed one-sided distributions as an explanation of the occurence of positive (negative) skewness in the case of stochastic production (cost) frontier analysis. It takes as example the binomial distribution that can have negative or positive skew and

  11. Dimension theoretical study on skew product maps with coupled-expanding property

    Directory of Open Access Journals (Sweden)

    Jinhyon Kim

    2014-03-01

    Full Text Available We discuss on some families of skew product maps on a square. For a kind of skew product maps with coupled-expanding property, we estimate Hausdorff dimension of its attractor. And we prove that there exists an ergodic measure with full Hausdorff dimension for this kind of skew product maps.

  12. Regularized multivariate regression models with skew-t error distributions

    KAUST Repository

    Chen, Lianfu

    2014-06-01

    We consider regularization of the parameters in multivariate linear regression models with the errors having a multivariate skew-t distribution. An iterative penalized likelihood procedure is proposed for constructing sparse estimators of both the regression coefficient and inverse scale matrices simultaneously. The sparsity is introduced through penalizing the negative log-likelihood by adding L1-penalties on the entries of the two matrices. Taking advantage of the hierarchical representation of skew-t distributions, and using the expectation conditional maximization (ECM) algorithm, we reduce the problem to penalized normal likelihood and develop a procedure to minimize the ensuing objective function. Using a simulation study the performance of the method is assessed, and the methodology is illustrated using a real data set with a 24-dimensional response vector. © 2014 Elsevier B.V.

  13. Universal relation between skewness and kurtosis in complex dynamics.

    Science.gov (United States)

    Cristelli, Matthieu; Zaccaria, Andrea; Pietronero, Luciano

    2012-06-01

    We identify an important correlation between skewness and kurtosis for a broad class of complex dynamic systems and present a specific analysis of earthquake and financial time series. Two regimes of non-Gaussianity can be identified: a parabolic one, which is common in various fields of physics, and a power law one, with exponent 4/3, which at the moment appears to be specific of earthquakes and financial markets. For this property we propose a model and an interpretation in terms of very rare events dominating the statistics independently on the nature of the events considered. The predicted scaling relation between skewness and kurtosis matches very well the experimental pattern of the second regime. Regarding price fluctuations, this situation characterizes a universal stylized fact.

  14. Neural Network Approach to Railway Stand Lateral SKEW Control

    Directory of Open Access Journals (Sweden)

    Peter Mark Benes

    2014-02-01

    Full Text Available The paper presents a study of an adaptive approach to lateral skew co ntrol for an experimental railway stand. The preliminary experiments with the real ex perimental railway stand and simulations with its 3-D mechanical model, indicates difficulties of model-based control of the device. Thus, use of neural networks for identification and c ontrol of lateral skew shall be investigated. This paper focuses on real-data based modelling of the railway stand by various neural network models, i.e; linear neural unit and quadratic neur al unit architectures. Furthermore, training methods of these neural architecture s as such, real-time-recurrent- learning and a variation of back-propagation-through-time are exam ined, accompanied by a discussion of the produced experimental results

  15. Estimating incremental costs with skew: a cautionary note.

    Science.gov (United States)

    Polgreen, Linnea A; Brooks, John M

    2012-09-01

    Cost data in healthcare are often skewed across patients. Thus, researchers have used either a log transformation of the dependent variable or generalized linear models with log links. However, frequently these non-linear approaches produce non-linear incremental effects: the incremental effects differ at different levels of the covariates, and this can cause dramatic effects on predicted cost. The aim of this study was to demonstrate that when modelling skewed data, log link functions or log transformations are not necessary and have unintended effects. We simulated cost data using a linear model with a 'treatment', a covariate and a specified number of observations with excessive cost (skewed data). We also used actual data from a pain-relief intervention among hip-replacement patients. We then estimated cost models using various functional approaches suggested to handle skew and calculated the incremental cost of treatment at various levels of the covariate(s). All of these methods provide unbiased estimates of the incremental effect of treatment on costs at the mean level of the covariate. However, in some log-based models the implied incremental treatment cost doubled between extreme low and high values of the covariate in a manner inconsistent with the underlying linear model. Although specification checks are always needed, the potential for misleading incremental estimates resulting from log-based specifications is often ignored. In this era of cost containment and comparisons of treatment effectiveness it is vital that researchers and policymakers understand the limitation of the inferences that can be made using log-based models for patients whose characteristics differ from the sample mean.

  16. MEASURING LOCAL GRADIENT AND SKEW QUADRUPOLE ERRORS IN RHIC IRS.

    Energy Technology Data Exchange (ETDEWEB)

    CARDONA,J.; PEGGS,S.; PILAT,R.; PTITSYN,V.

    2004-07-05

    The measurement of local linear errors at RHIC interaction regions using an ''action and phase'' analysis of difference orbits has already been presented. This paper evaluates the accuracy of this technique using difference orbits that were taken when known gradient errors and skew quadrupole errors were intentionally introduced. It also presents action and phase analysis of simulated orbits when controlled errors are intentionally placed in a RHIC simulation model.

  17. Incorporating Skew into RMS Surface Roughness Probability Distribution

    Science.gov (United States)

    Stahl, Mark T.; Stahl, H. Philip.

    2013-01-01

    The standard treatment of RMS surface roughness data is the application of a Gaussian probability distribution. This handling of surface roughness ignores the skew present in the surface and overestimates the most probable RMS of the surface, the mode. Using experimental data we confirm the Gaussian distribution overestimates the mode and application of an asymmetric distribution provides a better fit. Implementing the proposed asymmetric distribution into the optical manufacturing process would reduce the polishing time required to meet surface roughness specifications.

  18. Conformal string operators and evolution of skewed parton distributions

    CERN Document Server

    Kivel, N A

    1999-01-01

    We have investigated skewed parton distributions in coordinate space. We found that their evolution can be described in a simple manner in terms of non-local, conformal operators introduced by Balitsky and Braun. The resulting formula is given by a Neumann series expansion. Its structure resembles, for all values of the asymmetry parameter, the well-known solution of the ERBL equation in the momentum space. Performing Fourier transformation we have reproduced known results for evolution of momentum-space distributions.

  19. The skew product Markov chain%Markov-双链

    Institute of Scientific and Technical Information of China (English)

    张王月; 张金洪; 邹健

    2001-01-01

    就随机环境下的 Markov-链,介绍了 Markov-双链的构造,并证明了以已给 P(θ )为转移概率的 Markov-双链的存在性 .当环境空间和状态空间均可数时,希望通过对 Markov-双链的研究,进而实现对随机环境下的 Markov-链的研究 .%The process of the construction of the skew product Markov Chain on the basic of the Markov Chain in random environments is introduced and the existence of the skew product Markov Chain is proven, taking the given P(θ ) as the transition probability. The Markov Chain in random environments by studying the skew product Markov chain , can be studied when the environment space and the state space are countable.

  20. Tide and skew surge independence: New insights for flood risk

    Science.gov (United States)

    Williams, Joanne; Horsburgh, Kevin J.; Williams, Jane A.; Proctor, Robert N. F.

    2016-06-01

    Storm surges are a significant hazard to coastal communities around the world, putting lives at risk and costing billions of dollars in damage. Understanding how storm surges and high tides interact is crucial for estimating extreme water levels so that we can protect coastal communities. We demonstrate that in a tidal regime the best measure of a storm surge is the skew surge, the difference between the observed and predicted high water within a tidal cycle. Based on tide gauge records spanning decades from the UK, U.S., Netherlands, and Ireland we show that the magnitude of high water exerts no influence on the size of the most extreme skew surges. This is the first systematic proof that any storm surge can occur on any tide, which is essential for understanding worst-case scenarios. The lack of surge generation dependency on water depth emphasizes the dominant natural variability of weather systems in an observation-based analysis. Weak seasonal relationships between skew surges and high waters were identified at a minority of locations where long-period changes to the tidal cycle interact with the storm season. Our results allow advances to be made in methods for estimating the joint probabilities of storm surges and tides.

  1. Central limit theorem behavior in the skew tent map

    Energy Technology Data Exchange (ETDEWEB)

    Mackey, Michael C. [Departments of Physiology, Physics and Mathematics and Centre for Nonlinear Dynamics, McGill University, 3655 Promenade Sir William Osler, Montreal, Que., Canada H3G 1Y6 (Canada)], E-mail: michael.mackey@mcgill.ca; Tyran-Kaminska, Marta [Institute of Mathematics, University of Silesia, ul. Bankowa 14, 40-007 Katowice (Poland)], E-mail: mtyran@us.edu.pl

    2008-11-15

    In this paper we study and establish central limit theorem behavior in the skew (generalized) tent map transformation T: Y {yields}Y originally considered by Billings and Bollt [Billings L, Bollt EM. Probability density functions of some skew tent maps. Chaos, Solitons and Fractals 2001; 12: 365-376] and Ito et al. [Ito S, Tanaka S, Nakada H. On unimodal linear transformations and chaos. II. Tokyo J Math 1979; 2: 241-59]. When the measure {nu} is invariant under T, the transfer operator P{sub T}:L{sup 1}({nu}){yields}L{sup 1}({nu}) governing the evolution of densities f under the action of the skew tent map, as well as the unique stationary density, are given explicitly for specific transformation parameters. Then, using this development, we solve the Poisson equation f=P{sub T}f+{phi} for two specific integrable observables {phi} and explicitly calculate the variance {sigma}({phi}){sup 2}={integral}{sub Y}{phi}{sup 2}(y){nu}(dy)

  2. Kurtosis, skewness, and non-Gaussian cosmological density perturbations

    Science.gov (United States)

    Luo, Xiaochun; Schramm, David N.

    1993-01-01

    Cosmological topological defects as well as some nonstandard inflation models can give rise to non-Gaussian density perturbations. Skewness and kurtosis are the third and fourth moments that measure the deviation of a distribution from a Gaussian. Measurement of these moments for the cosmological density field and for the microwave background temperature anisotropy can provide a test of the Gaussian nature of the primordial fluctuation spectrum. In the case of the density field, the importance of measuring the kurtosis is stressed since it will be preserved through the weakly nonlinear gravitational evolution epoch. Current constraints on skewness and kurtosis of primeval perturbations are obtained from the observed density contrast on small scales and from recent COBE observations of temperature anisotropies on large scales. It is also shown how, in principle, future microwave anisotropy experiments might be able to reveal the initial skewness and kurtosis. It is shown that present data argue that if the initial spectrum is adiabatic, then it is probably Gaussian, but non-Gaussian isocurvature fluctuations are still allowed, and these are what topological defects provide.

  3. Decisions at the brink: Locomotor experience affects infants’ use of social information on an adjustable drop-off

    Directory of Open Access Journals (Sweden)

    Lana B. Karasik

    2016-06-01

    Full Text Available How do infants decide what to do at the brink of a precipice? Infants could use two sources of information to guide their actions: perceptual information generated by their own exploratory activity and social information offered by their caregivers. The current study investigated the role of locomotor experience in using social information—both encouragement and discouragement—for descending drop-offs. Mothers of 30 infants (experienced 12-month-old crawlers, novice 12-month-old walkers, and experienced 18-month-old walkers encouraged and discouraged descent on a gradation of drop-offs (safe steps and risky cliffs. Novice walkers descended more frequently than experienced crawlers and walkers and fell while attempting to walk over impossibly high cliffs. All infants showed evidence of integrating perceptual and social information, but locomotor experience affected infants’ use of social messages, especially on risky drop-offs. Experienced crawlers and walkers selectively deferred to social information when perceptual information is ambiguous. In contrast, novice walkers took mothers’ advice inconsistently and only at extreme drop-offs.

  4. Decisions at the Brink: Locomotor Experience Affects Infants’ Use of Social Information on an Adjustable Drop-off

    Science.gov (United States)

    Karasik, Lana B.; Tamis-LeMonda, Catherine S.; Adolph, Karen E.

    2016-01-01

    How do infants decide what to do at the brink of a precipice? Infants could use two sources of information to guide their actions: perceptual information generated by their own exploratory activity and social information offered by their caregivers. The current study investigated the role of locomotor experience in using social information—both encouragement and discouragement—for descending drop-offs. Mothers of 30 infants (experienced 12-month-old crawlers, novice 12-month-old walkers, and experienced 18-month-old walkers) encouraged and discouraged descent on a gradation of drop-offs (safe “steps” and risky “cliffs”). Novice walkers descended more frequently than experienced crawlers and walkers and fell while attempting to walk over impossibly high cliffs. All infants showed evidence of integrating perceptual and social information, but locomotor experience affected infants’ use of social messages, especially on risky drop-offs. Experienced crawlers and walkers selectively deferred to social information when perceptual information is ambiguous. In contrast, novice walkers took mothers’ advice inconsistently and only at extreme drop-offs. PMID:27375507

  5. Cluster adjusted regression for displaced subject data (CARDS): Marginal inference under potentially informative temporal cluster size profiles.

    Science.gov (United States)

    Bible, Joe; Beck, James D; Datta, Somnath

    2016-06-01

    Ignorance of the mechanisms responsible for the availability of information presents an unusual problem for analysts. It is often the case that the availability of information is dependent on the outcome. In the analysis of cluster data we say that a condition for informative cluster size (ICS) exists when the inference drawn from analysis of hypothetical balanced data varies from that of inference drawn on observed data. Much work has been done in order to address the analysis of clustered data with informative cluster size; examples include Inverse Probability Weighting (IPW), Cluster Weighted Generalized Estimating Equations (CWGEE), and Doubly Weighted Generalized Estimating Equations (DWGEE). When cluster size changes with time, i.e., the data set possess temporally varying cluster sizes (TVCS), these methods may produce biased inference for the underlying marginal distribution of interest. We propose a new marginalization that may be appropriate for addressing clustered longitudinal data with TVCS. The principal motivation for our present work is to analyze the periodontal data collected by Beck et al. (1997, Journal of Periodontal Research 6, 497-505). Longitudinal periodontal data often exhibits both ICS and TVCS as the number of teeth possessed by participants at the onset of study is not constant and teeth as well as individuals may be displaced throughout the study.

  6. Risk-adjusted capitation based on the Diagnostic Cost Group Model: an empirical evaluation with health survey information

    NARCIS (Netherlands)

    L.M. Lamers (Leida)

    1999-01-01

    textabstractOBJECTIVE: To evaluate the predictive accuracy of the Diagnostic Cost Group (DCG) model using health survey information. DATA SOURCES/STUDY SETTING: Longitudinal data collected for a sample of members of a Dutch sickness fund. In the Netherlands the sickness

  7. The affective impact of financial skewness on neural activity and choice.

    Directory of Open Access Journals (Sweden)

    Charlene C Wu

    Full Text Available Few finance theories consider the influence of "skewness" (or large and asymmetric but unlikely outcomes on financial choice. We investigated the impact of skewed gambles on subjects' neural activity, self-reported affective responses, and subsequent preferences using functional magnetic resonance imaging (FMRI. Neurally, skewed gambles elicited more anterior insula activation than symmetric gambles equated for expected value and variance, and positively skewed gambles also specifically elicited more nucleus accumbens (NAcc activation than negatively skewed gambles. Affectively, positively skewed gambles elicited more positive arousal and negatively skewed gambles elicited more negative arousal than symmetric gambles equated for expected value and variance. Subjects also preferred positively skewed gambles more, but negatively skewed gambles less than symmetric gambles of equal expected value. Individual differences in both NAcc activity and positive arousal predicted preferences for positively skewed gambles. These findings support an anticipatory affect account in which statistical properties of gambles--including skewness--can influence neural activity, affective responses, and ultimately, choice.

  8. Chiropractic Adjustment

    Science.gov (United States)

    ... syndrome) A certain type of stroke (vertebral artery dissection) after neck manipulation Don't seek chiropractic adjustment ... Chiropractic treatment. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2015. Shekelle P, et al. Spinal ...

  9. A Dixmier-Moeglin equivalence for skew Laurent polynomial rings

    OpenAIRE

    Parks, James William Alexander

    2009-01-01

    The work of Dixmier in 1977 and Moeglin in 1980 show us that for a prime ideal $P$ in the universal enveloping algebra of a complex finite-dimensional Lie algebra the properties of being primitive, rational and locally closed in the Zariski topology are all equivalent. This equivalence is referred to as the Dixmier-Moeglin equivalence. In this thesis we will study skew Laurent polynomial rings of the form ${mathbb{C}}[x_1,ldots,x_d][z,z^{-1};sigma]$ where $sigma$ is a ${mathbb{C}}$-algebra au...

  10. Noetherianity of some degree two twisted skew-commutative algebras

    OpenAIRE

    Nagpal, Rohit; Sam, Steven V; Snowden, Andrew

    2016-01-01

    A major open problem in the theory of twisted commutative algebras (tca's) is proving noetherianity of finitely generated tca's. For bounded tca's this is easy, in the unbounded case, noetherianity is only known for Sym(Sym^2(C^\\infty)) and Sym(\\wedge^2(C^\\infty)). In this paper, we establish noetherianity for the skew-commutative versions of these two algebras, namely \\wedge(Sym^2(C^\\infty)) and \\wedge(\\wedge^2(C^\\infty)). The result depends on work of Serganova on the representation theory ...

  11. Light transmission for polymer fibers using skew and meridional rays

    Science.gov (United States)

    Tekelioglu, Murat

    This dissertation is concerned with the development of a light transmission model for polymer optical fibers having application in hybrid solar lighting (HSL) systems. Conceptually, the HSL system consists of a solar collector/receiver that focuses concentrated visible solar light onto a polymer optical fiber (up to 10-m-long) that transports the solar light to an interior space. For this study, the polymer optical fiber is a large-core (0.2-40 mm diameter) plastic optical fiber (POF) comprised of various lengths of straight and bent sections. Although there has been extensive research on the transmission of monochromatic light through optical fibers for the communications industry, there are relatively few publications for visible light transmission through POFs. These publications were critically reviewed in this research. It is shown that the light transmission can be described with either skew or meridional rays. For each ray type, the HSL system light transmission was determined as a function of fiber geometrical properties (core and cladding radii, bend radius, bend angle, and fiber length) and optical properties (core and clad refractive indices, absorption and scattering coefficients, core-clad rms roughness height, and core-clad interface defects loss coefficient). To do this, first, models were developed for separate straight and bent sections for multiple skew and meridional rays. Second, the straight and bent models were combined into a FORTRAN simulation program for an arbitrary fiber with a combination of arbitrary straight and bent sections. The input condition of the rays (arrangement of rays, incident angle, and intensity profile) is user-defined. Third, the simulation results were experimentally validated using two different POFs, twelve configurations of straight and bent fiber subsystems, and two ray types. These experimental comparisons show that the transmission model using meridional rays is slightly better than that with the skew rays. But

  12. Forecasting stock market volatility: Do realized skewness and kurtosis help?

    Science.gov (United States)

    Mei, Dexiang; Liu, Jing; Ma, Feng; Chen, Wang

    2017-09-01

    In this study, we investigate the predictability of the realized skewness (RSK) and realized kurtosis (RKU) to stock market volatility, that has not been addressed in the existing studies. Out-of-sample results show that RSK, which can significantly improve forecast accuracy in mid- and long-term, is more powerful than RKU in forecasting volatility. Whereas these variables are useless in short-term forecasting. Furthermore, we employ the realized kernel (RK) for the robustness analysis and the conclusions are consistent with the RV measures. Our results are of great importance for portfolio allocation and financial risk management.

  13. Detecting a Multi-Homed Device Using Clock Skew

    Science.gov (United States)

    2016-09-01

    private network and the other to the open Internet, this provides a possible access vector that bypasses the network’s firewall [4]. This threat...the threat of a multi-homed host serving as an access vector to a network is to be mitigated by the ability to detect the presence of such a host...cannot be exactly measured or known. The clock skew is a random variable α that is assumed to be Gaussian with a density function f( ). A confidence

  14. Helping Head Start Parents Promote Their Children's Kindergarten Adjustment: The Research-Based Developmentally Informed Parent Program.

    Science.gov (United States)

    Bierman, Karen L; Welsh, Janet A; Heinrichs, Brenda S; Nix, Robert L; Mathis, Erin T

    2015-01-01

    Head Start enhances school readiness during preschool, but effects diminish after children transition into kindergarten. Designed to promote sustained gains, the Research-based Developmentally Informed (REDI) Parent program (REDI-P) provided home visits before and after the kindergarten transition, giving parents evidence-based learning games, interactive stories, and guided pretend play to use with their children. To evaluate impact, two hundred 4-year-old children in Head Start REDI classrooms were randomly assigned to REDI-P or a comparison condition (mail-home math games). Beyond the effects of the classroom program, REDI-P promoted significant improvements in child literacy skills, academic performance, self-directed learning, and social competence, demonstrating the utility of the approach in promoting gains in cognitive and social-emotional skills evident after the transition into kindergarten.

  15. The role of flexible goal adjustment in the effect of informal caregiving on depressive symptoms: Evidence of a large population-based longitudinal study in Germany from 2002 to 2011.

    Science.gov (United States)

    Hajek, André; König, Hans-Helmut

    2017-02-01

    To determine the role of flexible goal adjustment in the impact of informal caregiving on depressive symptoms, using a longitudinal approach. Data were gathered from the German Ageing Survey. This is a population-based longitudinal study among community-dwelling individuals aged 40 and above in Germany. Data were derived from the second (2002), third (2008) and fourth (2011) wave, drawing on 10,994 observations. Flexible goal adjustment was assessed using a scale by Brandstädter and Renner. Informal caregiving was measured by asking the individuals whether they provide informal care. Depressive symptoms were quantified by using the Center for Epidemiological Studies Depression scale. Adjusting for several potential confounders, fixed effects regressions showed that the onset of informal caregiving markedly increased depressive symptoms. Furthermore, regressions revealed that this effect was significantly moderated by flexible goal adjustment. Our results highlight the importance of informal caregiving for depressive symptoms. Furthermore, the importance of flexible goal adjustment in the relation between informal caregiving and depressive symptoms should be emphasized. Efforts to increase flexible goal adjustment might be beneficial in reducing depressive symptoms among informal caregivers.

  16. Shape and distribution of Jones and Faddy's skew t random variable

    Directory of Open Access Journals (Sweden)

    Saipornchai, N.

    2005-09-01

    Full Text Available The purpose of this research is to find another way to generate Jones and Faddy's skew t random variable and to construct quantile table, coefficient of skewness, coefficient of kurtosis and coefficient of variation tables of Jones and Faddy's skew t distribution. Graphs of its probability density function and graphs of its distribution function are also presented. The results of this study show that Jones and Faddy's skew t random variable can be generated from a beta random variable on (-1,1. The coefficients of skewness and kurtosis of the distribution depend on parameters a and b. The coefficient of variation of Jones and Faddy's skew t distribution can be calculated.

  17. Skew cyclic codes over F_q+uF_q+vF_q+uvF_q

    Directory of Open Access Journals (Sweden)

    Ting Yao

    2015-09-01

    Full Text Available In this paper, we study skew cyclic codes over the ring $R=F_q+uF_q+vF_q+uvF_q$, where $u^{2}=u,v^{2}=v,uv=vu$, $q=p^{m}$ and $p$ is an odd prime. We investigate the structural properties of skew cyclic codes over $R$ through a decomposition theorem. Furthermore, we give a formula for the number of skew cyclic codes of length $n$ over $R.$

  18. Multivariate log-skew-elliptical distributions with applications to precipitation data

    KAUST Repository

    Marchenko, Yulia V.

    2009-07-13

    We introduce a family of multivariate log-skew-elliptical distributions, extending the list of multivariate distributions with positive support. We investigate their probabilistic properties such as stochastic representations, marginal and conditional distributions, and existence of moments, as well as inferential properties. We demonstrate, for example, that as for the log-t distribution, the positive moments of the log-skew-t distribution do not exist. Our emphasis is on two special cases, the log-skew-normal and log-skew-t distributions, which we use to analyze US national (univariate) and regional (multivariate) monthly precipitation data. © 2009 John Wiley & Sons, Ltd.

  19. Binomial Markov-Switching Multifractal model with Skewed t innovations and applications to Chinese SSEC Index

    Science.gov (United States)

    Liu, Yufang; Zhang, Weiguo; Fu, Junhui

    2016-11-01

    This paper presents the Binomial Markov-switching Multifractal (BMSM) model of asset returns with Skewed t innovations (BMSM-Skewed t for short), which considers the fat tails, skewness and multifractality in asset returns simultaneously. The parameters of BMSM-Skewed t model can be estimated by Maximum Likelihood (ML) methods, and volatility forecasting can be accomplished via Bayesian updating. In order to evaluate the performance of BMSM-Skewed t model, BMSM model with Normal innovations (BMSM-N), BMSM model with Student-t innovations (BMSM-t) and GARCH(1,1) models (GARCH-N, GARCH-t and GARCH-Skewed t) are chosen for comparison. Through empirical studies on Shanghai Stock Exchange Composite Index (SSEC), we find that for sample estimation, BMSM models outperform the GARCH(1,1) models through BIC and AIC rules, and BMSM-Skewed t performs the best among all the models due to its fat tails, skewness and multifractality. In addition, BMSM-Skewed t model dominates other models at most forecasting horizons for out-of-sample volatility forecasts in terms of MSE, MAE and SPA test.

  20. Techniques to estimate generalized skew coefficients of annual peak streamflow for natural basins in Texas

    Science.gov (United States)

    Judd, Linda J.; Asquith, William H.; Slade, Raymond M.

    1996-01-01

    This report presents two techniques to estimate generalized skew coefficients used for log-Pearson Type III peak-streamflow frequency analysis of natural basins in Texas. A natural basin has less than 10 percent impervious cover, and less than 10 percent of its drainage area is controlled by reservoirs. The estimation of generalized skew coefficients is based on annual peak and historical peak streamflow for all U.S. Geological Survey streamflow-gaging stations having at least 20 years of annual peak-streamflow record from natural basins in Texas. Station skew coefficients calculated for each of 255 Texas stations were used to estimate generalized skew coefficients for Texas.

  1. Salary adjustments

    CERN Multimedia

    HR Department

    2008-01-01

    In accordance with decisions taken by the Finance Committee and Council in December 2007, salaries are adjusted with effect from 1 January 2008. Scale of basic salaries and scale of stipends paid to fellows (Annex R A 5 and R A 6 respectively): increased by 0.71% with effect from 1 January 2008. As a result of the stability of the Geneva consumer price index, the following elements do not increase: a)\tFamily Allowance, Child Allowance and Infant Allowance (Annex R A 3); b)\tReimbursement of education fees: maximum amounts of reimbursement (Annex R A 4.01) for the academic year 2007/2008. Related adjustments will be applied, wherever applicable, to Paid Associates and Students. As in the past, the actual percentage increase of each salary position may vary, due to the application of a constant step value and rounding effects. Human Resources Department Tel. 73566

  2. Salary adjustments

    CERN Multimedia

    HR Department

    2008-01-01

    In accordance with decisions taken by the Finance Committee and Council in December 2007, salaries are adjusted with effect from 1 January 2008. Scale of basic salaries and scale of stipends paid to fellows (Annex R A 5 and R A 6 respectively): increased by 0.71% with effect from 1 January 2008. As a result of the stability of the Geneva consumer price index, following elements do not increase: a) Family Allowance, Child Allowance and Infant Allowance (Annex R A 3). b) Reimbursement of education fees: maximum amounts of reimbursement (Annex R A 4.01) for the academic year 2007/2008. Related adjustments will be implemented, wherever applicable, to Paid Associates and Students. As in the past, the actual percentage increase of each salary position may vary, due to the application of a constant step value and the rounding effects. Human Resources Department Tel. 73566

  3. Skewed birth sex ratio and premature mortality in elephants.

    Science.gov (United States)

    Saragusty, Joseph; Hermes, Robert; Göritz, Frank; Schmitt, Dennis L; Hildebrandt, Thomas B

    2009-10-01

    Sex allocation theories predict equal offspring number of both sexes unless differential investment is required or some competition exists. Left undisturbed, elephants reproduce well and in approximately even numbers in the wild. We report an excess of males are born and substantial juvenile mortality occurs, perinatally, in captivity. Studbook data on captive births (CB, n=487) and premature deaths (PD, 6 months with maternal insufficient milk production, natural hazards and accidents being the main causes. European Asian and Myanmar elephants PD was biased towards males (0.71, P=0.024 and 0.56, P<0.001, respectively). The skewed birth sex ratio and high juvenile mortality hinder efforts to help captive populations become self-sustaining. Efforts should be invested to identify the mechanism behind these trends and seek solutions for them.

  4. On skew tau-functions in higher spin theory

    CERN Document Server

    Melnikov, D; Morozov, A

    2016-01-01

    Recent studies of higher spin theory in three dimensions concentrate on Wilson loops in Chern-Simons theory, which in the classical limit reduce to peculiar corner matrix elements between the highest and lowest weight states in a given representation of SL(N). Despite these "skew" tau-functions can seem very different from conventional ones, which are the matrix elements between the two highest weight states, they also satisfy the Toda recursion between different fundamental representations. Moreover, in the most popular examples they possess simple representations in terms of matrix models and Schur functions. We provide a brief introduction to this new interesting field, which, after quantization, can serve as an additional bridge between knot and integrability theories.

  5. Patterns of paternity skew among polyandrous social insects

    DEFF Research Database (Denmark)

    Jaffé, Rodolfo; Garcia-Gonzalez, Francisco; den Boer, Susanne

    2012-01-01

    Monogamy results in high genetic relatedness among offspring and thus it is generally assumed to be favored by kin selection. Female multiple mating (polyandry) has nevertheless evolved several times in the social Hymenoptera (ants, bees, and wasps), and a substantial amount of work has been...... conducted to understand its costs and benefits. Relatedness and inclusive fitness benefits are, however, not only influenced by queen mating frequency but also by paternity skew, which is a quantitative measure of paternity biases among the offspring of polyandrous females. We performed a large...... the potential for postcopulatory sexual selection to influence patterns of paternity in social insects, and suggest that sexual selection may have played a key, yet overlooked role in social evolution....

  6. Skewed gas flow technology offers antidote to opacity derates

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, M. [ATCO Power AB (Canada). Battle River Generating Station

    2001-06-01

    Deratings due to opacity problems at the Battle River Generating Station in Alberta, Canada led ATCO Power to evaluate and install skewed gas flow technology (SGFT) in one-half of the Unit 5 twin-casing electrostatic precipitator during the August 2000 outage. Preliminary operating results show that the modified casing produces opacity readings at the outlet 40% lower than those seen at the outlet of the unmodified casing. The dust loading tests indicate a 27.5% improvement in collector efficiency. This article includes a technical review and evaluation of Battle River's SGFT installation, as well as the rationale used to provide the initial economic justification. 3 figs., 1 tab., 1 photo.

  7. Soft bounds on diffusion produce skewed distributions and Gompertz growth

    Science.gov (United States)

    Mandrà, Salvatore; Lagomarsino, Marco Cosentino; Gherardi, Marco

    2014-09-01

    Constraints can affect dramatically the behavior of diffusion processes. Recently, we analyzed a natural and a technological system and reported that they perform diffusion-like discrete steps displaying a peculiar constraint, whereby the increments of the diffusing variable are subject to configuration-dependent bounds. This work explores theoretically some of the revealing landmarks of such phenomenology, termed "soft bound." At long times, the system reaches a steady state irreversibly (i.e., violating detailed balance), characterized by a skewed "shoulder" in the density distribution, and by a net local probability flux, which has entropic origin. The largest point in the support of the distribution follows a saturating dynamics, expressed by the Gompertz law, in line with empirical observations. Finally, we propose a generic allometric scaling for the origin of soft bounds. These findings shed light on the impact on a system of such "scaling" constraint and on its possible generating mechanisms.

  8. Julia Sets of Skew Products for Class MAp

    Institute of Scientific and Technical Information of China (English)

    王升

    2004-01-01

    Let fj ∈ M (j = 1, 2, …, m; m≥ 1) and (~f) be the skew product associated with the generator system {f1, f2, …, fm}. Then F (~f) is completely invariant under (~f); J((~f) is completely invariant under (~f); J (~f) is perfect; J (~f) has interior points if and only if F (~f) = φ; if fj ∈ MAp (p ≥ 5), j =1, 2, …, m, then the set of the repelling fixed points of (~f) of all orders are dense in J (~f).

  9. Skew-orthogonal polynomials and random matrix theory

    CERN Document Server

    Ghosh, Saugata

    2009-01-01

    Orthogonal polynomials satisfy a three-term recursion relation irrespective of the weight function with respect to which they are defined. This gives a simple formula for the kernel function, known in the literature as the Christoffel-Darboux sum. The availability of asymptotic results of orthogonal polynomials and the simple structure of the Christoffel-Darboux sum make the study of unitary ensembles of random matrices relatively straightforward. In this book, the author develops the theory of skew-orthogonal polynomials and obtains recursion relations which, unlike orthogonal polynomials, depend on weight functions. After deriving reduced expressions, called the generalized Christoffel-Darboux formulas (GCD), he obtains universal correlation functions and non-universal level densities for a wide class of random matrix ensembles using the GCD. The author also shows that once questions about higher order effects are considered (questions that are relevant in different branches of physics and mathematics) the ...

  10. Simple skew category algebras associated with minimal partially defined dynamical systems

    DEFF Research Database (Denmark)

    Nystedt, Patrik; Öinert, Per Johan

    2013-01-01

    In this article, we continue our study of category dynamical systems, that is functors s from a category G to Topop, and their corresponding skew category algebras. Suppose that the spaces s(e), for e∈ob(G), are compact Hausdorff. We show that if (i) the skew category algebra is simple, then (ii) G...

  11. Experimental study of the turbulent boundary layer in acceleration-skewed oscillatory flow

    NARCIS (Netherlands)

    A, van der D.A.; O'Donoghue, T.; Davies, A.G.; Ribberink, J.S.

    2011-01-01

    Experiments have been conducted in a large oscillatory flow tunnel to investigate the effects of acceleration skewness on oscillatory boundary layer flow over fixed beds. As well as enabling experimental investigation of the effects of acceleration skewness, the new experiments add substantially to

  12. The asymptotic distributions of the statistics of the skew elliptical variables

    Institute of Scientific and Technical Information of China (English)

    FANG Biqi

    2005-01-01

    In this paper, the asymptotic properties of the quadratic forms and the T statistic of the skew elliptical variables are studied. Consistent estimators of some parameters are obtained. The robustness of the significance level of the one-sided t test within the family of the skew normal family is investigated.

  13. Likelihood Inference of Nonlinear Models Based on a Class of Flexible Skewed Distributions

    Directory of Open Access Journals (Sweden)

    Xuedong Chen

    2014-01-01

    Full Text Available This paper deals with the issue of the likelihood inference for nonlinear models with a flexible skew-t-normal (FSTN distribution, which is proposed within a general framework of flexible skew-symmetric (FSS distributions by combining with skew-t-normal (STN distribution. In comparison with the common skewed distributions such as skew normal (SN, and skew-t (ST as well as scale mixtures of skew normal (SMSN, the FSTN distribution can accommodate more flexibility and robustness in the presence of skewed, heavy-tailed, especially multimodal outcomes. However, for this distribution, a usual approach of maximum likelihood estimates based on EM algorithm becomes unavailable and an alternative way is to return to the original Newton-Raphson type method. In order to improve the estimation as well as the way for confidence estimation and hypothesis test for the parameters of interest, a modified Newton-Raphson iterative algorithm is presented in this paper, based on profile likelihood for nonlinear regression models with FSTN distribution, and, then, the confidence interval and hypothesis test are also developed. Furthermore, a real example and simulation are conducted to demonstrate the usefulness and the superiority of our approach.

  14. Torque ripple minimization in a doubly salient permanent magnet motors by skewing the rotor teeth

    Science.gov (United States)

    Sheth, N. K.; Sekharbabu, A. R. C.; Rajagopal, K. R.

    2006-09-01

    This paper presents the effects of skewing the rotor teeth on the performance of an 8/6 doubly salient permanent magnet motor using a simple method, which utilizes the results obtained from the 2-D FE analysis. The optimum skewing angle is obtained as 12-15° for the least ripple torque without much reduction in the back-emf.

  15. Assessment of seismic performance of skew reinforced concrete box girder bridges

    Science.gov (United States)

    Abdel-Mohti, Ahmed; Pekcan, Gokhan

    2013-12-01

    The seismic vulnerability of highway bridges remains an important problem and has received increased attention as a consequence of unprecedented damage observed during several major earthquakes. A significant number of research studies have examined the performance of skew bridges under service and seismic loads. The results of these studies are particularly sensitive to modeling assumptions in view of the interacting parameters. In the present study, three-dimensional improved beam-stick models of two-span highway bridges with skew angles varying from 0° to 60° are developed to investigate the seismic response characteristics of skew box girder bridges. The relative accuracy of beam-stick models is verified against counterpart finite element models. The effect of various parameters and conditions on the overall seismic response was examined such as skew angle, ground motion intensity, soil condition, abutment support conditions, bridge aspect ratio, and foundation-base conditions. The study shows that the improved beam-stick models can be used to conduct accurate nonlinear time history analysis of skew bridges. Skew angle and interacting parameters were found to have significant effect on the behavior of skewed highway bridges. Furthermore, the performance of shear keys may have a predominant effect on the overall seismic response of the skew bridges.

  16. Does Realized Skewness Predict the Cross-Section of Equity Returns?

    DEFF Research Database (Denmark)

    Amaya, Diego; Christoffersen, Peter; Jacobs, Kris

    2015-01-01

    We use intraday data to compute weekly realized moments for equity returns and study their time-series and cross-sectional properties. Buying stocks in the lowest realized skewness decile and selling stocks in the highest realized skewness decile generates an average return of 19 basis points the...

  17. Neoclassical versus Frontier Production Models ? Testing for the Skewness of Regression Residuals

    DEFF Research Database (Denmark)

    Kuosmanen, T; Fosgerau, Mogens

    2009-01-01

    The empirical literature on production and cost functions is divided into two strands. The neoclassical approach concentrates on model parameters, while the frontier approach decomposes the disturbance term to a symmetric noise term and a positively skewed inefficiency term. We propose a theoreti......The empirical literature on production and cost functions is divided into two strands. The neoclassical approach concentrates on model parameters, while the frontier approach decomposes the disturbance term to a symmetric noise term and a positively skewed inefficiency term. We propose...... a theoretical justification for the skewness of the inefficiency term, arguing that this skewness is the key testable hypothesis of the frontier approach. We propose to test the regression residuals for skewness in order to distinguish the two competing approaches. Our test builds directly upon the asymmetry...

  18. Simultaneous Optimization of Skew and Control Step Assignments in RT-Datapath Synthesis

    Science.gov (United States)

    Obata, Takayuki; Kaneko, Mineo

    As well as the schedule affects system performance, the control skew, i.e., the arrival time difference of control signals between registers, can be utilized for improving the system performance, enhancing robustness against delay variations, etc. The simultaneous optimization of the control step assignment and the control skew assignment is more powerful technique in improving performance. In this paper, firstly, we prove that, even if the execution sequence of operations which are assigned to the same resource is fixed, the simultaneous optimization problem under a fixed clock period is NP-hard. Secondly, we propose a heuristic algorithm for the simultaneous control step and skew optimization under given clock period, and we show how much the simultaneous optimization improves system performance. This paper is the first one that uses the intentional skew to shorten control steps under a specified clock period. The proposed algorithm has the potential to play a central role in various scenarios of skew-aware high level synthesis.

  19. Adjustable reed for weaving net-shaped tailored fabrics

    Science.gov (United States)

    Farley, Gary L. (Inventor)

    1995-01-01

    An apparatus and method for forming woven fabrics through the use of an adjustable reed. The adjustable reed has multiple groups of reed wires that guide the warp yarns. The groups of reed wires move on reed rails parallel to the warp direction. In addition, rail expanders permit the space between the reed wires to be modified and telescoping rods attached to the rail sliders can be turned to permit the reed wires to be skewed to alter the fill yarn angle. These adjustments to the reed permit simultaneous variation of fill yarn angles and fabric widths and allow these variations to be made during fabrication, without the need to halt production.

  20. The Relationship Between Skewed X Chromosome Inactivation and the Prognosis of Graves' and Hashimoto's Diseases

    Science.gov (United States)

    Ishido, Naoko; Inoue, Naoya; Watanabe, Mikio; Hidaka, Yoh

    2015-01-01

    Background: Autoimmune thyroid diseases (AITDs) predominantly develop in females. One of two X chromosomes is randomly inactivated by methylation in each female cell, but it has been reported that skewed X chromosome inactivation (XCI) may be associated with the development of autoimmune diseases. To clarify the significance of skewed XCI in the prognosis and development of AITD, we investigated the proportion of skewed XCI in female patients with AITD. Methods: We analyzed the degree of XCI skewing in 120 female patients with AITD (77 patients with Graves' disease [GD] and 43 patients with Hashimoto's disease [HD]) and 49 female controls in DNA from peripheral blood mononuclear cells (PBMC). We performed XCI analysis by digesting inactive DNA with a methylation-sensitive restriction enzyme (HpaII) followed by a polymerase chain reaction (PCR) assay for the polymorphic CAG repeat of the androgen receptor gene and electrophoresis of the PCR products. Results: The proportion of skewed XCI (≥65% skewing) was not significantly different between AITD patients and control subjects but was higher in patients with intractable GD (66.7%) than those with GD in remission (25.0%, p=0.0033) and control subjects (32.6%, p=0.0038). When the cutoff value for XCI skewing was relaxed, the proportion of skewed XCI (≥60% skewing) was higher in patients with severe HD (76.5%) than in those with mild HD (41.2%, p=0.0342). Conclusions: Skewed XCI is related to the prognosis of AITD, particularly the intractability of GD. PMID:25338305

  1. Skewness of cloud droplet spectrum and an improved estimation for its relative dispersion

    Science.gov (United States)

    Liu, Yu; Lu, Chunsong; Li, Weiliang

    2017-02-01

    The relative dispersion of the cloud droplet spectrum is a very important parameter in describing and modeling cloud microphysical processes. Based on the definition of skewness as well as theoretical and data analyses, a linear fitting relationship ( α = 2.91 ɛ-0.59) between skewness ( α) and relative dispersion ( ɛ) is established and a new method is developed to estimate the relative dispersion of the cloud droplet spectrum. The new method does not depend on any assumption of a particular distribution for the cloud droplet spectrum and has broader applicability than the previous methods. Comparisons of the three methods for the relative dispersion with the observed data supported the following conclusions. (1) The skewness of the cloud droplet spectrum is asymmetrically distributed. An assumption of zero skewness in quantifying the relative dispersion inevitably results in relatively large deviations from the observations. Errors of the estimated relative dispersion due to the omission of the skewness term are not solely related to the skewness, but rather to the product of the skewness and relative dispersion. (2) The use of the assumption that the cloud droplet spectrum takes a gamma distribution is similar to the assumption that the skewness is twice the relative dispersion. This leads to a better accuracy in estimating the relative dispersion than that with zero skewness assumption. (3) Comparisons with observations show that the new method is more accurate than the one under gamma distribution assumption and is the best among all the three methods. (4) It is believed that finding a better correlation between the skewness and the relative dispersion would further reduce the deviations for the estimated relative dispersion.

  2. Weighted triangulation adjustment

    Science.gov (United States)

    Anderson, Walter L.

    1969-01-01

    The variation of coordinates method is employed to perform a weighted least squares adjustment of horizontal survey networks. Geodetic coordinates are required for each fixed and adjustable station. A preliminary inverse geodetic position computation is made for each observed line. Weights associated with each observed equation for direction, azimuth, and distance are applied in the formation of the normal equations in-the least squares adjustment. The number of normal equations that may be solved is twice the number of new stations and less than 150. When the normal equations are solved, shifts are produced at adjustable stations. Previously computed correction factors are applied to the shifts and a most probable geodetic position is found for each adjustable station. Pinal azimuths and distances are computed. These may be written onto magnetic tape for subsequent computation of state plane or grid coordinates. Input consists of punch cards containing project identification, program options, and position and observation information. Results listed include preliminary and final positions, residuals, observation equations, solution of the normal equations showing magnitudes of shifts, and a plot of each adjusted and fixed station. During processing, data sets containing irrecoverable errors are rejected and the type of error is listed. The computer resumes processing of additional data sets.. Other conditions cause warning-errors to be issued, and processing continues with the current data set.

  3. Weighted triangulation adjustment

    Science.gov (United States)

    Anderson, Walter L.

    1969-01-01

    The variation of coordinates method is employed to perform a weighted least squares adjustment of horizontal survey networks. Geodetic coordinates are required for each fixed and adjustable station. A preliminary inverse geodetic position computation is made for each observed line. Weights associated with each observed equation for direction, azimuth, and distance are applied in the formation of the normal equations in-the least squares adjustment. The number of normal equations that may be solved is twice the number of new stations and less than 150. When the normal equations are solved, shifts are produced at adjustable stations. Previously computed correction factors are applied to the shifts and a most probable geodetic position is found for each adjustable station. Pinal azimuths and distances are computed. These may be written onto magnetic tape for subsequent computation of state plane or grid coordinates. Input consists of punch cards containing project identification, program options, and position and observation information. Results listed include preliminary and final positions, residuals, observation equations, solution of the normal equations showing magnitudes of shifts, and a plot of each adjusted and fixed station. During processing, data sets containing irrecoverable errors are rejected and the type of error is listed. The computer resumes processing of additional data sets.. Other conditions cause warning-errors to be issued, and processing continues with the current data set.

  4. Forecasting with Option-Implied Information

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Jacobs, Kris; Chang, Bo Young

    2013-01-01

    This chapter surveys the methods available for extracting information from option prices that can be used in forecasting. We consider option-implied volatilities, skewness, kurtosis, and densities. More generally, we discuss how any forecasting object that is a twice differentiable function...... of the future realization of the underlying risky asset price can utilize option-implied information in a well-defined manner. Going beyond the univariate option-implied density, we also consider results on option-implied covariance, correlation and beta forecasting, as well as the use of option......-implied information in cross-sectional forecasting of equity returns. We discuss how option-implied information can be adjusted for risk premia to remove biases in forecasting regressions....

  5. Audit of Provisions and Value Adjustments – a Very Important Objective for the Assessment of Information Comprised in the Financial Statements

    Directory of Open Access Journals (Sweden)

    Cristina IOVU

    2017-04-01

    Full Text Available Any type of entity must show in its financial statements information regarding its significant estimations concerning the future periods and other important sources of uncertainty at the date at which the financial statements are drafted, which presents an increased risk of generating an adjustment of the accounting value of the assets and debts in the future fiscal year. This information must include the nature of the estimations and their accounting value at the date of the balance sheet. The auditing of the financial statements in which accounting estimations are presented frame a high risk of significant distortion. Because of this, the auditor must obtain sufficient audit evidence which would certify if these estimations are reasonable, respectively if the data on which the estimations are based upon are accurate, complete and relevant, and the procedures and methods used for the development of the estimations are adequate for the balance sheet structures to which they apply. The development of provisions, as a manner to reflect uncertainties within the accounting system, contributes to the accurate representation of the company’s financial position. Such uncertainties are acknowledged through the presentation of their nature and value, but also through the exercising of prudence for the development of the financial statements. Prudence implies the identification of those accounting estimations, associated to the given uncertainties conditions, which would not over-evaluate the assets and the incomes, and the debts and expenses would not be under-evaluated. Exercising prudence should not allow, for instance, the accumulation of excessive provisions, the deliberate under-evaluation of assets and incomes, nor the deliberate over-evaluation of debts or expenses. This requirement is imperative, due to the fact that investors substantiate their economic decisions starting from the analysis of the financial statements, as accurate image of the

  6. Skew redundant MEMS IMU calibration using a Kalman filter

    Science.gov (United States)

    Jafari, M.; Sahebjameyan, M.; Moshiri, B.; Najafabadi, T. A.

    2015-10-01

    In this paper, a novel calibration procedure for skew redundant inertial measurement units (SRIMUs) based on micro-electro mechanical systems (MEMS) is proposed. A general model of the SRIMU measurements is derived which contains the effects of bias, scale factor error and misalignments. For more accuracy, the effect of lever arms of the accelerometers to the center of the table are modeled and compensated in the calibration procedure. Two separate Kalman filters (KFs) are proposed to perform the estimation of error parameters for gyroscopes and accelerometers. The predictive error minimization (PEM) stochastic modeling method is used to simultaneously model the effect of bias instability and random walk noise on the calibration Kalman filters to diminish the biased estimations. The proposed procedure is simulated numerically and has expected experimental results. The calibration maneuvers are applied using a two-axis angle turntable in a way that the persistency of excitation (PE) condition for parameter estimation is met. For this purpose, a trapezoidal calibration profile is utilized to excite different deterministic error parameters of the accelerometers and a pulse profile is used for the gyroscopes. Furthermore, to evaluate the performance of the proposed KF calibration method, a conventional least squares (LS) calibration procedure is derived for the SRIMUs and the simulation and experimental results compare the functionality of the two proposed methods with each other.

  7. On Splitting Rings for Azumaya Skew Polynomial Rings

    Institute of Scientific and Technical Information of China (English)

    George Szeto; Lianyong Xue

    2001-01-01

    Let B be a ring with 1, p an automorphism of B of order n for some integer n, and B[x; p] the skew polynomial ring in x over B such that 1, x,x2,... ,xn-1 are independent over B and xn ∈ U(Bp), where Bp is the set of elements in B fixed under p and U(Bρ) is the set of all units in Bρ. Let -ρ be the inner automorphism of B[x; p] induced by x. Assume n is a unit in B. It is shown that, for a -ρ-Galois extension B[x; p] over (B[x; ρ])-ρ (resp., a DeMeyer-Kanzaki Galois extention B over Bp), B[x; ρ] is Azumaya if and only if (B[x; ρ])-ρ (resp.,B) is Azumaya, and some splitting rings of B[x; ρ], (B[x; ρ])-ρ and B coincide.

  8. On Approximating Frequency Moments of Data Streams with Skewed Projections

    CERN Document Server

    Li, Ping

    2008-01-01

    We propose skewed stable random projections for approximating the pth frequency moments of dynamic data streams (01) improves previous methods based on (symmetric) stable random projections. Our proposed method is applicable to data streams that are (a) insertion only (the cash-register model); or (b) always non-negative (the strict Turnstile model), or (c) eventually non-negative at check points. This is only a minor restriction for practical applications. Our method works particularly well when p = 1+/- \\Delta and \\Delta is small, which is a practically important scenario. For example, \\Delta may be the decay rate or interest rate, which are usually small. Of course, when \\Delta = 0, one can compute the 1th frequent moment (i.e., the sum) essentially error-free using a simple couter. Our method may be viewed as a ``genearlized counter'' in that it can count the total value in the future, taking in account of the effect of decaying or interest accruement. In a summary, our contributions are two-fold. (A) Thi...

  9. Identification of Intellectual Disability Genes in Female Patients with a Skewed X-Inactivation Pattern.

    Science.gov (United States)

    Fieremans, Nathalie; Van Esch, Hilde; Holvoet, Maureen; Van Goethem, Gert; Devriendt, Koenraad; Rosello, Monica; Mayo, Sonia; Martinez, Francisco; Jhangiani, Shalini; Muzny, Donna M; Gibbs, Richard A; Lupski, James R; Vermeesch, Joris R; Marynen, Peter; Froyen, Guy

    2016-08-01

    Intellectual disability (ID) is a heterogeneous disorder with an unknown molecular etiology in many cases. Previously, X-linked ID (XLID) studies focused on males because of the hemizygous state of their X chromosome. Carrier females are generally unaffected because of the presence of a second normal allele, or inactivation of the mutant X chromosome in most of their cells (skewing). However, in female ID patients, we hypothesized that the presence of skewing of X-inactivation would be an indicator for an X chromosomal ID cause. We analyzed the X-inactivation patterns of 288 females with ID, and found that 22 (7.6%) had extreme skewing (>90%), which is significantly higher than observed in the general population (3.6%; P = 0.029). Whole-exome sequencing of 19 females with extreme skewing revealed causal variants in six females in the XLID genes DDX3X, NHS, WDR45, MECP2, and SMC1A. Interestingly, variants in genes escaping X-inactivation presumably cause both XLID and skewing of X-inactivation in three of these patients. Moreover, variants likely accounting for skewing only were detected in MED12, HDAC8, and TAF9B. All tested candidate causative variants were de novo events. Hence, extreme skewing is a good indicator for the presence of X-linked variants in female patients.

  10. COMPUTATIONAL AND EXPERIMENTAL STUDY ON TIP LEAKAGE VORTEX OF CIRCUMFERENTIAL SKEWED BLADES

    Institute of Scientific and Technical Information of China (English)

    LI Yang; OUYANG Hua; DU Zhaohui

    2007-01-01

    In the steady operation condition, the experiments and the numerical simulations are used to investigate the tip leakage flow fields in three low pressure axial flow fans with three kinds of circumferential skewed rotors, including the radial rotor, the forward-skewed rotor and the backward-skewed rotor. The three-dimensional viscous flow fields of the fans are computed. In the experiments, the two-dimensional plane particle image velocimetry (PIV) system is used to measure the flow fields in the tip region of three different pitchwise positions of each fan. The results show that the computational results agree well with the experimental data in the flow field of the tip region of each fan. The tip leakage vortex core segments based on method of the eigenmode analysis can display clearly some characteristics of the tip leakage vortex, such as the origination position of tip leakage vortex, the development of vortex strength, and so on. Compared with the radial rotor, the other two skewed rotors can increase the stability of the tip leakage vortex and the increment in the forward-skewed rotor is more than that in the backward-skewed one. Among the tip leakage vortices of the three rotors, the velocity of the vortex in the forward-skewed rotor is the highest in the circumferential direction and the lowest in the axial direction.

  11. Social and genetic structure of paper wasp cofoundress associations: tests of reproductive skew models.

    Science.gov (United States)

    Field, J; Solís, C R; Queller, D C; Strassmann, J E

    1998-06-01

    Recent models postulate that the members of a social group assess their ecological and social environments and agree a "social contract" of reproductive partitioning (skew). We tested social contracts theory by using DNA microsatellites to measure skew in 24 cofoundress associations of paper wasps, Polistes bellicosus. In contrast to theoretical predictions, there was little variation in cofoundress relatedness, and relatedness either did not predict skew or was negatively correlated with it; the dominant/subordinate size ratio, assumed to reflect relative fighting ability, did not predict skew; and high skew was associated with decreased aggression by the rank 2 subordinate toward the dominant. High skew was associated with increased group size. A difficulty with measuring skew in real systems is the frequent changes in group composition that commonly occur in social animals. In P. bellicosus, 61% of egg layers and an unknown number of non-egg layers were absent by the time nests were collected. The social contracts models provide an attractive general framework linking genetics, ecology, and behavior, but there have been few direct tests of their predictions. We question assumptions underlying the models and suggest directions for future research.

  12. Genetic variation in nuclear and mitochondrial markers supports a large sex difference in lifetime reproductive skew in a lekking species

    NARCIS (Netherlands)

    Verkuil, Yvonne I.; Juillet, Cedric; Lank, David B.; Widemo, Fredrik; Piersma, Theunis

    2014-01-01

    Sex differences in skews of vertebrate lifetime reproductive success are difficult to measure directly. Evolutionary histories of differential skew should be detectable in the genome. For example, male-biased skew should reduce variation in the biparentally inherited genome relative to the maternall

  13. Inferences in Linear Mixed Models with Skew-normal Random Eff ects

    Institute of Scientific and Technical Information of China (English)

    Ren Dao YE; Tong Hui WANG

    2015-01-01

    For the linear mixed model with skew-normal random eff ects, this paper gives the density function, moment generating function and independence conditions. The noncentral skew chi-square distribution is defined and its density function is shown. The necessary and suffi cient conditions under which a quadratic form is distributed as noncentral skew chi-square distribution are obtained. Also, a version of Cochran’s theorem is given, which modifies the result of Wang et al. (2009) and is used to set up exact tests for fixed eff ects and variance components of the proposed model. For illustration, our main results are applied to a real data problem.

  14. Analysis of domain wall dynamics based on skewness of magnetic Barkhausen noise for applied stress determination

    Science.gov (United States)

    Ding, Song; Tian, GuiYun; Dobmann, Gerd; Wang, Ping

    2017-01-01

    Skewness of Magnetic Barkhausen Noise (MBN) signal is used as a new feature for applied stress determination. After experimental studies, skewness presents its ability for measuring applied tensile stress compared with conventional feature, meanwhile, a non-linear behavior of this new feature and an independence of the excitation conditions under compressive stress are found and discussed. Effective damping during domain wall motion influencing the asymmetric shape of the MBN statistical distribution function is discussed under compressive and tensile stress variation. Domain wall (DW) energy and distance between pinning edges of the DW are considered altering the characteristic relaxation time, which is the reason for the non-linear phenomenon of skewness.

  15. FEM-based Analysis of a Hybrid Synchronous Generator with Skewed Stator Slots

    Directory of Open Access Journals (Sweden)

    MUNTEANU, A.

    2011-11-01

    Full Text Available The paper presents a simulation study of a hybrid synchronous generator (dual excitation system - permanent magnets and electromagnets with skewed stator slots. The main goal is to establish if the skewing of the slots brings a significant improvement of the air-gap flux density and of the induced stator voltage. The skewness angle is the parameter in discussion. The study is based on finite element method analysis. Due to the particular geometry of the stator slots, a multilayer approach is employed.

  16. Genetic architecture of skewed X inactivation in the laboratory mouse.

    Directory of Open Access Journals (Sweden)

    John D Calaway

    Full Text Available X chromosome inactivation (XCI is the mammalian mechanism of dosage compensation that balances X-linked gene expression between the sexes. Early during female development, each cell of the embryo proper independently inactivates one of its two parental X-chromosomes. In mice, the choice of which X chromosome is inactivated is affected by the genotype of a cis-acting locus, the X-chromosome controlling element (Xce. Xce has been localized to a 1.9 Mb interval within the X-inactivation center (Xic, yet its molecular identity and mechanism of action remain unknown. We combined genotype and sequence data for mouse stocks with detailed phenotyping of ten inbred strains and with the development of a statistical model that incorporates phenotyping data from multiple sources to disentangle sources of XCI phenotypic variance in natural female populations on X inactivation. We have reduced the Xce candidate 10-fold to a 176 kb region located approximately 500 kb proximal to Xist. We propose that structural variation in this interval explains the presence of multiple functional Xce alleles in the genus Mus. We have identified a new allele, Xce(e present in Mus musculus and a possible sixth functional allele in Mus spicilegus. We have also confirmed a parent-of-origin effect on X inactivation choice and provide evidence that maternal inheritance magnifies the skewing associated with strong Xce alleles. Based on the phylogenetic analysis of 155 laboratory strains and wild mice we conclude that Xce(a is either a derived allele that arose concurrently with the domestication of fancy mice but prior the derivation of most classical inbred strains or a rare allele in the wild. Furthermore, we have found that despite the presence of multiple haplotypes in the wild Mus musculus domesticus has only one functional Xce allele, Xce(b. Lastly, we conclude that each mouse taxa examined has a different functional Xce allele.

  17. Generalized peak skew coefficients for Oklahoma, 1961-1990 base period.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital-map data set consists of a grid of generalized skew coefficients of logarithms of annual maximum streamflow for Oklahoma streams less than or equal to...

  18. The Carnot Cycle and Area-Specific Work Equivalence on a Skew T-logp Diagram

    National Research Council Canada - National Science Library

    Alex DeCaria

    2008-01-01

      Attempts to calculate the area to specific work equivalence on a skew T-logp diagram for a Carnot cycle can lead to large errors if the pressures of the nodes of the cycle are estimated from the diagram...

  19. The Process of price formation and the skewness of asset returns

    CERN Document Server

    Reimann, S

    2006-01-01

    Distributions of assets returns exhibit a slight skewness. In this note we show that our model of endogenous price formation \\cite{Reimann2006} creates an asymmetric return distribution if the price dynamics are a process in which consecutive trading periods are dependent from each other in the sense that opening prices equal closing prices of the former trading period. The corresponding parameter $\\alpha$ is estimated from daily prices from 01/01/1999 - 12/31/2004 for 9 large indices. For the S&P 500, the skewness distribution of all its constituting assets is also calculated. The skewness distribution due to our model is compared with the distribution of the empirical skewness values of the ingle assets.

  20. On nomenclature for, and the relative merits of, two formulations of skew distributions

    KAUST Repository

    Azzalini, Adelchi

    2015-12-21

    We examine some skew distributions used extensively within the model-based clustering literature in recent years, paying special attention to claims that have been made about their relative efficacy. Theoretical arguments are provided as well as real data examples.

  1. Asymptotic performance of the quadratic discriminant function to skewed training samples.

    Science.gov (United States)

    Adebanji, Atinuke; Asamoah-Boaheng, Michael; Osei-Tutu, Olivia

    2016-01-01

    This study investigates the asymptotic performance of the quadratic discriminant function (QDF) under skewed training samples. The main objective of this study is to evaluate the performance of the QDF under skewed distribution considering different sample size ratios, varying the group centroid separators and the number of variables. Three populations [Formula: see text] with increasing group centroid separator function were considered. A multivariate normal distributed data was simulated with MatLab R2009a. There was an increase in the average error rates of the sample size ratios 1:2:2 and 1:2:3 as the total sample size increased asymptotically in the skewed distribution when the centroid separator increased from 1 to 3. The QDF under the skewed distribution performed better for the sample size ratio 1:1:1 as compared to the other sampling ratios and under centroid separator [Formula: see text].

  2. CONCEPTS OF DICHOTOMY FOR SKEW-EVOLUTION SEMIFLOWS IN BANACH SPACES

    Directory of Open Access Journals (Sweden)

    Mihail Megan

    2011-01-01

    Full Text Available In this paper we investigate some dichotomy concepts for skew-evolution semiflows in Banachspaces.Our main objective is to estab-lish relations between these concepts.We motivate our approach byillustrative examples.

  3. INTERNAL FLOW MECHANISM AND EXPERIMENTAL RESEARCH OF LOW PRESSURE AXIAL FAN WITH FORWARD-SKEWED BLADES

    Institute of Scientific and Technical Information of China (English)

    LI Yang; LIU Jie; OUYANG Hua; DU Zhao-Hui

    2008-01-01

    This article presents the flow mechanism analysis and experimental study of a forward-skewed impeller and a radial impeller in low pressure axial fan. The forward-skewed blade was obtained by the optimization design of the radial blade and CFD technique. Measurement of the two blades was carried out in aerodynamic and aeroacoustic performance. Compared to the radial blade, the forward-skewed blade has demonstrated the improvements in efficiency, total pressure ratio, Stable Operating Range (SOR) and less aerodynamic noise. Detailed flow measurement and computation were performed for outlet flow field for investigating the responsible flow mechanisms. The results show the forward-skewed blade can cause a spanwise redistribution of flow toward the blade mid-span and reduce tip loading. This results in reduced significantly total pressure loss near hub and shroud endwall region, despite the slight increase of total pressure loss at mid-span.

  4. 3D Rigid-Plastic Finite Element Analysis for Skew Rolling Process of the Stepped Part

    Institute of Scientific and Technical Information of China (English)

    Gang FANG; Pan ZENG

    2003-01-01

    Based on rigid-plastic finite element method, a skew rolling process of stepped part is simulated. Considering nodesaving and effective remeshing, the tetrahedron solid elements are used to discrete workpiece. The workpiece material adopts rigid-plastic m

  5. Widely Linear Blind Adaptive Equalization for Transmitter IQ-Imbalance/Skew Compensation in Multicarrier Systems

    DEFF Research Database (Denmark)

    Porto da Silva, Edson; Zibar, Darko

    2016-01-01

    Simple analytical widely linear complex-valued models for IQ-imbalance and IQ-skew effects in multicarrier transmitters are presented. To compensate for such effects, a 4×4 MIMO widely linear adaptive equalizer is proposed and experimentally validated.......Simple analytical widely linear complex-valued models for IQ-imbalance and IQ-skew effects in multicarrier transmitters are presented. To compensate for such effects, a 4×4 MIMO widely linear adaptive equalizer is proposed and experimentally validated....

  6. Normalization of High Dimensional Genomics Data Where the Distribution of the Altered Variables Is Skewed

    Science.gov (United States)

    Landfors, Mattias; Philip, Philge; Rydén, Patrik; Stenberg, Per

    2011-01-01

    Genome-wide analysis of gene expression or protein binding patterns using different array or sequencing based technologies is now routinely performed to compare different populations, such as treatment and reference groups. It is often necessary to normalize the data obtained to remove technical variation introduced in the course of conducting experimental work, but standard normalization techniques are not capable of eliminating technical bias in cases where the distribution of the truly altered variables is skewed, i.e. when a large fraction of the variables are either positively or negatively affected by the treatment. However, several experiments are likely to generate such skewed distributions, including ChIP-chip experiments for the study of chromatin, gene expression experiments for the study of apoptosis, and SNP-studies of copy number variation in normal and tumour tissues. A preliminary study using spike-in array data established that the capacity of an experiment to identify altered variables and generate unbiased estimates of the fold change decreases as the fraction of altered variables and the skewness increases. We propose the following work-flow for analyzing high-dimensional experiments with regions of altered variables: (1) Pre-process raw data using one of the standard normalization techniques. (2) Investigate if the distribution of the altered variables is skewed. (3) If the distribution is not believed to be skewed, no additional normalization is needed. Otherwise, re-normalize the data using a novel HMM-assisted normalization procedure. (4) Perform downstream analysis. Here, ChIP-chip data and simulated data were used to evaluate the performance of the work-flow. It was found that skewed distributions can be detected by using the novel DSE-test (Detection of Skewed Experiments). Furthermore, applying the HMM-assisted normalization to experiments where the distribution of the truly altered variables is skewed results in considerably higher

  7. Normalization of high dimensional genomics data where the distribution of the altered variables is skewed.

    Directory of Open Access Journals (Sweden)

    Mattias Landfors

    Full Text Available Genome-wide analysis of gene expression or protein binding patterns using different array or sequencing based technologies is now routinely performed to compare different populations, such as treatment and reference groups. It is often necessary to normalize the data obtained to remove technical variation introduced in the course of conducting experimental work, but standard normalization techniques are not capable of eliminating technical bias in cases where the distribution of the truly altered variables is skewed, i.e. when a large fraction of the variables are either positively or negatively affected by the treatment. However, several experiments are likely to generate such skewed distributions, including ChIP-chip experiments for the study of chromatin, gene expression experiments for the study of apoptosis, and SNP-studies of copy number variation in normal and tumour tissues. A preliminary study using spike-in array data established that the capacity of an experiment to identify altered variables and generate unbiased estimates of the fold change decreases as the fraction of altered variables and the skewness increases. We propose the following work-flow for analyzing high-dimensional experiments with regions of altered variables: (1 Pre-process raw data using one of the standard normalization techniques. (2 Investigate if the distribution of the altered variables is skewed. (3 If the distribution is not believed to be skewed, no additional normalization is needed. Otherwise, re-normalize the data using a novel HMM-assisted normalization procedure. (4 Perform downstream analysis. Here, ChIP-chip data and simulated data were used to evaluate the performance of the work-flow. It was found that skewed distributions can be detected by using the novel DSE-test (Detection of Skewed Experiments. Furthermore, applying the HMM-assisted normalization to experiments where the distribution of the truly altered variables is skewed results in

  8. Optimization Design and Experimental Study of Low-Pressure Axial Fan with Forward-Skewed Blades

    OpenAIRE

    2007-01-01

    This paper presents an experimental study of the optimization of blade skew in low pressure axial fan. Using back propagation (BP) neural network and genetic algorithm (GA), the optimization was performed for a radial blade. An optimized blade is obtained through blade forward skew. Measurement of the two blades was carried out in aerodynamic and aeroacoustic performance. Compared to the radial blade, the optimized blade demonstrated improvements in efficiency, total pres...

  9. Adjustment computations spatial data analysis

    CERN Document Server

    Ghilani, Charles D

    2011-01-01

    the complete guide to adjusting for measurement error-expanded and updated no measurement is ever exact. Adjustment Computations updates a classic, definitive text on surveying with the latest methodologies and tools for analyzing and adjusting errors with a focus on least squares adjustments, the most rigorous methodology available and the one on which accuracy standards for surveys are based. This extensively updated Fifth Edition shares new information on advances in modern software and GNSS-acquired data. Expanded sections offer a greater amount of computable problems and their worked solu

  10. Opposite GC skews at the 5' and 3' ends of genes in unicellular fungi

    Directory of Open Access Journals (Sweden)

    McLean Malcolm A

    2011-12-01

    Full Text Available Abstract Background GC-skews have previously been linked to transcription in some eukaryotes. They have been associated with transcription start sites, with the coding strand G-biased in mammals and C-biased in fungi and invertebrates. Results We show a consistent and highly significant pattern of GC-skew within genes of almost all unicellular fungi. The pattern of GC-skew is asymmetrical: the coding strand of genes is typically C-biased at the 5' ends but G-biased at the 3' ends, with intermediate skews at the middle of genes. Thus, the initiation, elongation, and termination phases of transcription are associated with different skews. This pattern influences the encoded proteins by generating differential usage of amino acids at the 5' and 3' ends of genes. These biases also affect fourfold-degenerate positions and extend into promoters and 3' UTRs, indicating that skews cannot be accounted by selection for protein function or translation. Conclusions We propose two explanations, the mutational pressure hypothesis, and the adaptive hypothesis. The mutational pressure hypothesis is that different co-factors bind to RNA pol II at different phases of transcription, producing different mutational regimes. The adaptive hypothesis is that cytidine triphosphate deficiency may lead to C-avoidance at the 3' ends of transcripts to control the flow of RNA pol II molecules and reduce their frequency of collisions.

  11. Mapping of quantitative trait loci using the skew-normal distribution

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In standard interval mapping (IM) of quantitative trait loci (QTL), the QTL effect is described by a normal mixture model. When this assumption of normality is violated, the most commonly adopted strategy is to use the previous model after data transformation. However, an appropriate transformation may not exist or may be difficult to find. Also this approach can raise interpretation issues. An interesting alternative is to consider a skew-normal mixture model in standard IM, and the resulting method is here denoted as skew-normal IM. This flexible model that includes the usual symmetric normal distribution as a special case is important, allowing continuous variation from normality to non-normality. In this paper we briefly introduce the main peculiarities of the skew-normal distribution. The maximum likelihood estimates of parameters of the skew-normal distribution are obtained by the expectation-maximization (EM) algorithm. The proposed model is illustrated with real data from an intercross experiment that shows a significant departure from the normality assumption. The performance of the skew-normal IM is assessed via stochastic simulation. The results indicate that the skew-normal IM has higher power for QTL detection and better precision of QTL location as compared to standard IM and nonparametric IM.

  12. Bayesian linear regression with skew-symmetric error distributions with applications to survival analysis

    KAUST Repository

    Rubio, Francisco J.

    2016-02-09

    We study Bayesian linear regression models with skew-symmetric scale mixtures of normal error distributions. These kinds of models can be used to capture departures from the usual assumption of normality of the errors in terms of heavy tails and asymmetry. We propose a general noninformative prior structure for these regression models and show that the corresponding posterior distribution is proper under mild conditions. We extend these propriety results to cases where the response variables are censored. The latter scenario is of interest in the context of accelerated failure time models, which are relevant in survival analysis. We present a simulation study that demonstrates good frequentist properties of the posterior credible intervals associated with the proposed priors. This study also sheds some light on the trade-off between increased model flexibility and the risk of over-fitting. We illustrate the performance of the proposed models with real data. Although we focus on models with univariate response variables, we also present some extensions to the multivariate case in the Supporting Information.

  13. Polyandry and paternity skew in natural and experimental populations of Drosophila serrata.

    Science.gov (United States)

    Frentiu, Francesca D; Chenoweth, Stephen F

    2008-03-01

    Many species engage in polyandry, resulting in the potential for sexual selection to continue post-copulation through sperm competition and/or cryptic female choice. The relative importance of pre- vs. post-copulatory processes remains unknown for most species despite this information being fundamental for understanding the evolutionary consequences of sexual selection. The Australian fruit fly Drosophila serrata has become a prominent model system for studying precopulatory sexual selection, such as mating preferences and their influence on the evolution of sexually selected traits. Here, we investigated polyandry and the potential for post-copulatory sexual selection in this species using indirect paternity analysis. We genotyped 21 wild-caught and 19 laboratory-reared mothers and their offspring (a total of 787 flies) at six microsatellite loci and found extensive polyandry, with all broods surveyed having at least two sires. Female remating rates were higher than in other Drosophila surveyed to date and no significant differences were found between laboratory and field populations. Additionally, we found evidence for biased sperm usage in several broods of D. serrata. Paternity skew occurred more frequently in broods from the field population than the laboratory one, suggesting differences between the two environments in the level of post-copulatory sexual selection. Our data suggest that D. serrata represents a promising system for studying the interaction between pre- and post-copulatory sexual selection in driving the evolution of sexually selected phenotypes.

  14. Quantitative Method for the Optimal Subtraction of Continuum Emission from Narrow-band Images : Skewness Transition Analysis

    CERN Document Server

    Hong, Sungryong; Dickinson, Mark

    2013-01-01

    We present an objective method to remove the stellar continuum emission from narrow-band images to derive emission-line images. The method is based on the skewness of the pixel histogram of the residual images. Specifically, we exploit a transition in the skewness of the signal in the continuum-subtracted image, which appears when the image changes from being under-subtracted to over-subtracted. Tests on one-dimensional artificial images demonstrate that the transition identifies the optimal scaling factor {\\mu} to be used on the broad-band image IB in order to produce the optimal line-emission image IE, i.e., IE =IN - {\\mu} IB, with IN the original (un-subtracted) narrow-band image. The advantage of this method is that it uses all information-bearing pixels in the final image, and not just a sub-set of those pixels (the latter being common in many traditional approaches to stellar continuum removal from narrow-band images). We apply our method to actual images, both from ground-based and space facilities, in...

  15. Post-error behavioral adjustments are facilitated by activation and suppression of task-relevant and task-irrelevant information processing

    NARCIS (Netherlands)

    King, J.A.; Korb, F.M.; Cramon, D.Y. von; Ullsperger, M.

    2010-01-01

    Error monitoring by the posterior medial frontal cortex (pMFC) has been linked to post-error behavioral adaptation effects and cognitive control dynamics in lateral prefrontal cortex (LPFC). It remains unknown, however, whether control adjustments following errors produce post-error behavioral adjus

  16. Quantitative analysis of mutation and selection pressures on base composition skews in bacterial chromosomes

    Directory of Open Access Journals (Sweden)

    Chen Carton W

    2007-08-01

    Full Text Available Abstract Background Most bacterial chromosomes exhibit asymmetry of base composition with respect to leading vs. lagging strands (GC and AT skews. These skews reflect mainly those in protein coding sequences, which are driven by asymmetric mutation pressures during replication and transcription (notably asymmetric cytosine deamination plus subsequent selection for preferred structures, signals, amino acid or codons. The transcription-associated effects but not the replication-associated effects contribute to the overall skews through the uneven distribution of the coding sequences on the leading and lagging strands. Results Analysis of 185 representative bacterial chromosomes showed diverse and characteristic patterns of skews among different clades. The base composition skews in the coding sequences were used to derive quantitatively the effect of replication-driven mutation plus subsequent selection ('replication-associated pressure', RAP, and the effect of transcription-driven mutation plus subsequent selection at translation level ('transcription-associate pressure', TAP. While different clades exhibit distinct patterns of RAP and TAP, RAP is absent or nearly absent in some bacteria, but TAP is present in all. The selection pressure at the translation level is evident in all bacteria based on the analysis of the skews at the three codon positions. Contribution of asymmetric cytosine deamination was found to be weak to TAP in most phyla, and strong to RAP in all the Proteobacteria but weak in most of the Firmicutes. This possibly reflects the differences in their chromosomal replication machineries. A strong negative correlation between TAP and G+C content and between TAP and chromosomal size were also revealed. Conclusion The study reveals the diverse mutation and selection forces associated with replication and transcription in various groups of bacteria that shape the distinct patterns of base composition skews in the chromosomes during

  17. Static performance investigation of a skewed-throat multiaxis thrust-vectoring nozzle concept

    Science.gov (United States)

    Wing, David J.

    1994-01-01

    The static performance of a jet exhaust nozzle which achieves multiaxis thrust vectoring by physically skewing the geometric throat has been characterized in the static test facility of the 16-Foot Transonic Tunnel at NASA Langley Research Center. The nozzle has an asymmetric internal geometry defined by four surfaces: a convergent-divergent upper surface with its ridge perpendicular to the nozzle centerline, a convergent-divergent lower surface with its ridge skewed relative to the nozzle centerline, an outwardly deflected sidewall, and a straight sidewall. The primary goal of the concept is to provide efficient yaw thrust vectoring by forcing the sonic plane (nozzle throat) to form at a yaw angle defined by the skewed ridge of the lower surface contour. A secondary goal is to provide multiaxis thrust vectoring by combining the skewed-throat yaw-vectoring concept with upper and lower pitch flap deflections. The geometric parameters varied in this investigation included lower surface ridge skew angle, nozzle expansion ratio (divergence angle), aspect ratio, pitch flap deflection angle, and sidewall deflection angle. Nozzle pressure ratio was varied from 2 to a high of 11.5 for some configurations. The results of the investigation indicate that efficient, substantial multiaxis thrust vectoring was achieved by the skewed-throat nozzle concept. However, certain control surface deflections destabilized the internal flow field, which resulted in substantial shifts in the position and orientation of the sonic plane and had an adverse effect on thrust-vectoring and weight flow characteristics. By increasing the expansion ratio, the location of the sonic plane was stabilized. The asymmetric design resulted in interdependent pitch and yaw thrust vectoring as well as nonzero thrust-vector angles with undeflected control surfaces. By skewing the ridges of both the upper and lower surface contours, the interdependency between pitch and yaw thrust vectoring may be eliminated

  18. Characteristic function-based semiparametric inference for skew-symmetric models

    KAUST Repository

    Potgieter, Cornelis J.

    2012-12-26

    Skew-symmetric models offer a very flexible class of distributions for modelling data. These distributions can also be viewed as selection models for the symmetric component of the specified skew-symmetric distribution. The estimation of the location and scale parameters corresponding to the symmetric component is considered here, with the symmetric component known. Emphasis is placed on using the empirical characteristic function to estimate these parameters. This is made possible by an invariance property of the skew-symmetric family of distributions, namely that even transformations of random variables that are skew-symmetric have a distribution only depending on the symmetric density. A distance metric between the real components of the empirical and true characteristic functions is minimized to obtain the estimators. The method is semiparametric, in that the symmetric component is specified, but the skewing function is assumed unknown. Furthermore, the methodology is extended to hypothesis testing. Two tests for a hypothesis of specific parameter values are considered, as well as a test for the hypothesis that the symmetric component has a specific parametric form. A resampling algorithm is described for practical implementation of these tests. The outcomes of various numerical experiments are presented. © 2012 Board of the Foundation of the Scandinavian Journal of Statistics.

  19. Handling Data Skew in MapReduce Cluster by Using Partition Tuning

    Directory of Open Access Journals (Sweden)

    Yufei Gao

    2017-01-01

    Full Text Available The healthcare industry has generated large amounts of data, and analyzing these has emerged as an important problem in recent years. The MapReduce programming model has been successfully used for big data analytics. However, data skew invariably occurs in big data analytics and seriously affects efficiency. To overcome the data skew problem in MapReduce, we have in the past proposed a data processing algorithm called Partition Tuning-based Skew Handling (PTSH. In comparison with the one-stage partitioning strategy used in the traditional MapReduce model, PTSH uses a two-stage strategy and the partition tuning method to disperse key-value pairs in virtual partitions and recombines each partition in case of data skew. The robustness and efficiency of the proposed algorithm were tested on a wide variety of simulated datasets and real healthcare datasets. The results showed that PTSH algorithm can handle data skew in MapReduce efficiently and improve the performance of MapReduce jobs in comparison with the native Hadoop, Closer, and locality-aware and fairness-aware key partitioning (LEEN. We also found that the time needed for rule extraction can be reduced significantly by adopting the PTSH algorithm, since it is more suitable for association rule mining (ARM on healthcare data.

  20. Handling Data Skew in MapReduce Cluster by Using Partition Tuning

    Science.gov (United States)

    Zhou, Yanjie; Zhou, Bing; Shi, Lei

    2017-01-01

    The healthcare industry has generated large amounts of data, and analyzing these has emerged as an important problem in recent years. The MapReduce programming model has been successfully used for big data analytics. However, data skew invariably occurs in big data analytics and seriously affects efficiency. To overcome the data skew problem in MapReduce, we have in the past proposed a data processing algorithm called Partition Tuning-based Skew Handling (PTSH). In comparison with the one-stage partitioning strategy used in the traditional MapReduce model, PTSH uses a two-stage strategy and the partition tuning method to disperse key-value pairs in virtual partitions and recombines each partition in case of data skew. The robustness and efficiency of the proposed algorithm were tested on a wide variety of simulated datasets and real healthcare datasets. The results showed that PTSH algorithm can handle data skew in MapReduce efficiently and improve the performance of MapReduce jobs in comparison with the native Hadoop, Closer, and locality-aware and fairness-aware key partitioning (LEEN). We also found that the time needed for rule extraction can be reduced significantly by adopting the PTSH algorithm, since it is more suitable for association rule mining (ARM) on healthcare data.

  1. New Multivariate Skew t Distributions Generated from Skew Pearson Ⅷ Distributions%从偏态Pearson Ⅶ分布生成的新的多元偏态t分布

    Institute of Scientific and Technical Information of China (English)

    温阳俊; 朱道元

    2009-01-01

    一般而言,偏态的椭球等高分布是一类分布族,有相当一部分的分布都是积分形式,且此类积分不易求出,而偏态的正态、偏态的正态尺度混合、偏态的PⅦ型、偏态的PⅡ型的分布却有着很好的结构,偏态t分布属于偏态PⅦ型分布,因此,本文在偏态PⅦ型分布的基础上着重研究新的偏态t分布,给出它的背景、定义、两种随机表示及其等价性.%In general, there are a large number of skew elliptically contoured distributions with hard calculated integral forms, while skew normal, skew normal scale mixtures, skew Pearson type Ⅷ and skew Pearson type Ⅱ distributions possess good structures. Skew t distributions belong to skew Pearson type Ⅷ distributions, therefore, this paper proposes new multivariate skew t distributions based on multivariate skew Pearson type Ⅷ distributions. Backgrounds and definitions are given, two stochastic representations and their equivalence are derived.

  2. Occupation and Local Times for Skew Brownian Motion with Applications to Dispersion Across an Interface

    CERN Document Server

    Appuhamillage, Thilanka; Thomann, Enrique; Waymire, Edward; Wood, Brian

    2010-01-01

    Advective skew dispersion is a natural Markov process defined by a diffusion with drift across an interface of jump discontinuity in a piecewise constant diffusion coefficient. In the absence of drift, this process may be represented as a function of $\\alpha$-skew Brownian motion for a uniquely determined value of $\\alpha=\\alpha^*$; see Ramirez et al. (2006). In the present paper, the analysis is extended to the case of nonzero drift. A determination of the (joint) distributions of key functionals of standard skew Brownian motion together with some associated probabilistic semigroup and local time theory is given for these purposes. An application to the dispersion of a solute concentration across an interface is provided that explains certain symmetries and asymmetries in recently reported laboratory experiments conducted at Lawrence-Livermore Berkeley Labs by Berkowitz et al. (2009).

  3. PS-Modules over Ore Extensions and Skew Generalized Power Series Rings

    Directory of Open Access Journals (Sweden)

    Refaat M. Salem

    2015-01-01

    Full Text Available A right R-module MR is called a PS-module if its socle, SocMR, is projective. We investigate PS-modules over Ore extension and skew generalized power series extension. Let R be an associative ring with identity, MR a unitary right R-module, O=Rx;α,δ Ore extension, MxO a right O-module, S,≤ a strictly ordered additive monoid, ω:S→EndR a monoid homomorphism, A=RS,≤,ω the skew generalized power series ring, and BA=MS,≤RS,≤, ω the skew generalized power series module. Then, under some certain conditions, we prove the following: (1 If MR is a right PS-module, then MxO is a right PS-module. (2 If MR is a right PS-module, then BA is a right PS-module.

  4. A Cable-Passive Damper System for Sway and Skew Motion Control of a Crane Spreader

    Directory of Open Access Journals (Sweden)

    La Duc Viet

    2015-01-01

    Full Text Available While the crane control problem is often approached by applying a certain active control command to some parts of the crane, this paper proposes a cable-passive damper system to reduce the vibration of a four-cable suspended crane spreader. The residual sway and skew motions of a crane spreader always produce the angle deflections between the crane cables and the crane spreader. The idea in this paper is to convert those deflections into energy dissipated by the viscous dampers, which connect the cables and the spreader. The proposed damper system is effective in reducing spreader sway and skew motions. Moreover, the optimal damping coefficient can be found analytically by minimizing the time integral of system energy. The numerical simulations show that the proposed passive system can assist the input shaping control of the trolley motion in reducing both sway and skew responses.

  5. Skewed Normal Distribution Of Return Assets In Call European Option Pricing

    Directory of Open Access Journals (Sweden)

    Evy Sulistianingsih

    2011-12-01

    Full Text Available Option is one of security derivates. In financial market, option is a contract that gives a right (notthe obligation for its owner to buy or sell a particular asset for a certain price at a certain time.Option can give a guarantee for a risk that can be faced in a market.This paper studies about theuse of Skewed Normal Distribution (SN in call europeanoption pricing. The SN provides aflexible framework that captures the skewness of log return. We obtain aclosed form solution forthe european call option pricing when log return follow the SN. Then, we will compare optionprices that is obtained by the SN and the Black-Scholes model with the option prices of market. Keywords: skewed normaldistribution, log return, options.

  6. Temporal Skewness of Electromagnetic Pulsed Waves Propagating Through Random Media with Embedded Irregularity Slab

    Institute of Scientific and Technical Information of China (English)

    许正文; 吴健; 霍文平; 吴振森

    2003-01-01

    Electromagnetic pulsed waves can be distorted in the propagation through random media, and their energy dis tributions change along the leading and trailing edge of the waveform, which can be presented by the temporal skewness. The skewness presents asymmetry and is treated by the third-order temporal moment, in which an analytic solution for the two-frequency mutual coherence function is obtained recently. Then, transionospheric pulses are discussed in details. Both theoretical analysis and numerical computation indicate that the contri butions from scattering and dispersion of irregularities dominate over those of background, so the latter can be neglected in most cases. Also, the temporal skewness of a transionospheric pulse is negative and energy is shifted to the leading edge.

  7. Evolution of Quantitative Traits under a Migration-Selection Balance: When Does Skew Matter?

    Science.gov (United States)

    Débarre, Florence; Yeaman, Sam; Guillaume, Frédéric

    2015-10-01

    Quantitative-genetic models of differentiation under migration-selection balance often rely on the assumption of normally distributed genotypic and phenotypic values. When a population is subdivided into demes with selection toward different local optima, migration between demes may result in asymmetric, or skewed, local distributions. Using a simplified two-habitat model, we derive formulas without a priori assuming a Gaussian distribution of genotypic values, and we find expressions that naturally incorporate higher moments, such as skew. These formulas yield predictions of the expected divergence under migration-selection balance that are more accurate than models assuming Gaussian distributions, which illustrates the importance of incorporating these higher moments to assess the response to selection in heterogeneous environments. We further show with simulations that traits with loci of large effect display the largest skew in their distribution at migration-selection balance.

  8. Effect of skewing the rotor teeth on the performance of doubly salient permanent magnet motors

    Science.gov (United States)

    Sheth, N. K.; Sekharbabu, A. R. C.; Rajagopal, K. R.

    2006-04-01

    This paper presents the effects of skewing the rotor teeth on the performance characteristics such as flux linkage, back emf, phase inductance, and reluctance torque of an 8/6 doubly salient permanent magnet motor using a simple method, which utilizes the results obtained from the two-dimensional finite element analysis. The optimum skewing angle is obtained as 12°-15° for the least ripple torque without much reduction in the back emf. Skewing the rotor teeth of an 8/6 doubly salient permanent magnet motor by 12°-15° will reduce the total harmonic distortion of the back emf profile to 29.69% from the original value of 44.69%. The reduction in the amplitude of the back emf in this case will be 18.79% only.

  9. Enhanced responsivity with skew ray excitation of reflection- and transmission-type refractometric sensors.

    Science.gov (United States)

    Chen, George Y; Codemard, Christophe A; Lewis, Richard J; Jankowski, Lukasz; Chan, Jaclyn S; Gorman, Philip M; Zervas, Michalis N

    2014-07-01

    The responsivity of optical fibers to refractive index can be enhanced using high-order skew rays compared with using meridional rays. Skew rays can have a much higher number of reflections with increased interaction length along the core-cladding interface, which gives rise to stronger interactions with the external medium. Reflection/transmission-type refractometric sensors based on twin-coupled-core and multimode fibers showed one/two orders of magnitude increase in responsivity with skew ray excitation. The responsivity and sensitivity for the two types are ~2000%/RIU, ~1400%/RIU, and 4.9×10⁻⁵  RIU, 7.0×10⁻⁵  RIU, respectively.

  10. The Curious Anomaly of Skewed Judgment Distributions and Systematic Error in the Wisdom of Crowds

    DEFF Research Database (Denmark)

    Nash, Ulrik William

    2014-01-01

    Judgment distributions are often skewed and we know little about why. This paper explains the phenomenon of skewed judgment distributions by introducing the augmented quincunx (AQ) model of sequential and probabilistic cue categorization by neurons of judges. In the process of developing inferences...... be inferred from how skewed their judgment distributions are, and in what direction they tilt. This implies not just that judgment distributions are shaped by cues, but that judgment distributions are cues themselves for the wisdom of crowds. The AQ model also predicts that judgment variance correlates......, and implications are discussed with reference to three central ideas on collective intelligence, these being Galton's conjecture on the distribution of judgments, Muth's rational expectations hypothesis, and Page's diversity prediction theorem....

  11. Effect of PCC Joint Skew on Reflective Cracking in HMA Overlays

    CERN Document Server

    Ghauch, By Ziad G

    2011-01-01

    Reflective cracking is a relatively premature distress that occurs in HMA materials overlaying cracked and jointed underlying pavements. The high concentration of stresses and strains in the vicinity of the discontinuity of the old pavement causes the cracks to reflect into the newly placed HMA overlay. While it is a common practice to use skewed transverse joints in rigid pavements to improve the latter's performance, the impact of such a practice on the cracking of a potential HMA overlay has not been examined so far. In this context, this study investigates the effect of using skewed transverse joints in rigid pavements on reflective cracking development in the HMA overlay. Advanced three-dimensional Finite Element models including viscoelastic material properties for the HMA overlay, 3D beam modeling of dowel bars, non-uniform tire-pavement contact stresses, friction interfaces, and infinite boundary elements were constructed for both normal and skewed transverse joints using ABAQUS v-6.11. The potential ...

  12. Skew-Laplace and Cell-Size Distribution in Microbial Axenic Cultures: Statistical Assessment and Biological Interpretation

    Directory of Open Access Journals (Sweden)

    Olga Julià

    2010-01-01

    Full Text Available We report a skew-Laplace statistical analysis of both flow cytometry scatters and cell size from microbial strains primarily grown in batch cultures, others in chemostat cultures and bacterial aquatic populations. Cytometry scatters best fit the skew-Laplace distribution while cell size as assessed by an electronic particle analyzer exhibited a moderate fitting. Unlike the cultures, the aquatic bacterial communities clearly do not fit to a skew-Laplace distribution. Due to its versatile nature, the skew-Laplace distribution approach offers an easy, efficient, and powerful tool for distribution of frequency analysis in tandem with the flow cytometric cell sorting.

  13. Measurement of the Width and Skewness of Elliptic Flow Fluctuations in PbPb Collisions at 5.02~TeV with CMS

    CERN Document Server

    Castle, James Robert

    2017-01-01

    Flow harmonic fluctuations are studied for PbPb collisions at $\\sqrt{s_{NN}} = 5.02~\\mathrm{TeV}$ using the CMS detector at the LHC. Flow harmonic probability distributions $p\\left(v_2\\right)$ are obtained by unfolding smearing effects from observed azimuthal anisotropy distributions using particles of $0.3 < p_{\\mathrm{T}} < 3.0~\\mathrm{GeV}/c$ and $\\lvert \\eta \\rvert < 1.0$. Cumulant flow harmonics are determined from the moments of $p\\left(v_2\\right)$ and used to estimate the standardized elliptic flow skewness. Hydrodynamic models predict this skewness to be negative with respect to the reaction plane. A statistically significant negative skewness is observed for all centrality bins as evidenced by a splitting between $v_2\\left\\{4\\right\\}$, $v_2\\left\\{6\\right\\}$, and $v_2\\left\\{8\\right\\}$ cumulants. Elliptic power law distribution fits are made to $p\\left(v_2\\right)$ distributions to infer information on the nature of initial-state eccentricity distributions and found to provide a more accurate d...

  14. Elevated mortality among birds in Chernobyl as judged from skewed age and sex ratios.

    Science.gov (United States)

    Møller, Anders Pape; Bonisoli-Alquati, Andrea; Rudolfsen, Geir; Mousseau, Timothy A

    2012-01-01

    Radiation has negative effects on survival of animals including humans, although the generality of this claim is poorly documented under low-dose field conditions. Because females may suffer disproportionately from the effects of radiation on survival due to differences in sex roles during reproduction, radiation-induced mortality may result in male-skewed adult sex ratios. We estimated the effects of low-dose radiation on adult survival rates in birds by determining age ratios of adults captured in mist nets during the breeding season in relation to background radiation levels around Chernobyl and in nearby uncontaminated control areas. Age ratios were skewed towards yearlings, especially in the most contaminated areas, implying that adult survival rates were reduced in contaminated areas, and that populations in such areas could only be maintained through immigration from nearby uncontaminated areas. Differential mortality in females resulted in a strongly male-skewed sex ratio in the most contaminated areas. In addition, males sang disproportionately commonly in the most contaminated areas where the sex ratio was male skewed presumably because males had difficulty finding and acquiring mates when females were rare. The results were not caused by permanent emigration by females from the most contaminated areas because none of the recaptured birds had changed breeding site, and the proportion of individuals with morphological abnormalities did not differ significantly between the sexes for areas with normal and higher levels of contamination. These findings are consistent with the hypothesis that the adult survival rate of female birds is particularly susceptible to the effects of low-dose radiation, resulting in male skewed sex ratios at high levels of radiation. Such skewed age ratios towards yearlings in contaminated areas are consistent with the hypothesis that an area exceeding 30,000 km(2) in Chernobyl's surroundings constitutes an ecological trap that

  15. Elevated mortality among birds in Chernobyl as judged from skewed age and sex ratios.

    Directory of Open Access Journals (Sweden)

    Anders Pape Møller

    Full Text Available BACKGROUND: Radiation has negative effects on survival of animals including humans, although the generality of this claim is poorly documented under low-dose field conditions. Because females may suffer disproportionately from the effects of radiation on survival due to differences in sex roles during reproduction, radiation-induced mortality may result in male-skewed adult sex ratios. METHODOLOGY/PRINCIPAL FINDING: We estimated the effects of low-dose radiation on adult survival rates in birds by determining age ratios of adults captured in mist nets during the breeding season in relation to background radiation levels around Chernobyl and in nearby uncontaminated control areas. Age ratios were skewed towards yearlings, especially in the most contaminated areas, implying that adult survival rates were reduced in contaminated areas, and that populations in such areas could only be maintained through immigration from nearby uncontaminated areas. Differential mortality in females resulted in a strongly male-skewed sex ratio in the most contaminated areas. In addition, males sang disproportionately commonly in the most contaminated areas where the sex ratio was male skewed presumably because males had difficulty finding and acquiring mates when females were rare. The results were not caused by permanent emigration by females from the most contaminated areas because none of the recaptured birds had changed breeding site, and the proportion of individuals with morphological abnormalities did not differ significantly between the sexes for areas with normal and higher levels of contamination. CONCLUSIONS/SIGNIFICANCE: These findings are consistent with the hypothesis that the adult survival rate of female birds is particularly susceptible to the effects of low-dose radiation, resulting in male skewed sex ratios at high levels of radiation. Such skewed age ratios towards yearlings in contaminated areas are consistent with the hypothesis that an area

  16. Mean-Variance-Skewness-Entropy Measures: A Multi-Objective Approach for Portfolio Selection

    Directory of Open Access Journals (Sweden)

    Yeliz Mert Kantar

    2011-01-01

    Full Text Available In this study, we present a multi-objective approach based on a mean-variance-skewness-entropy portfolio selection model (MVSEM. In this approach, an entropy measure is added to the mean-variance-skewness model (MVSM to generate a well‑diversified portfolio. Through a variety of empirical data sets, we evaluate the performance of the MVSEM in terms of several portfolio performance measures. The obtained results show that the MVSEM performs well out-of sample relative to traditional portfolio selection models.

  17. Fuzzy cross-entropy, mean, variance, skewness models for portfolio selection

    Directory of Open Access Journals (Sweden)

    Rupak Bhattacharyya

    2014-01-01

    Full Text Available In this paper, fuzzy stock portfolio selection models that maximize mean and skewness as well as minimize portfolio variance and cross-entropy are proposed. Because returns are typically asymmetric, in addition to typical mean and variance considerations, third order moment skewness is also considered in generating a larger payoff. Cross-entropy is used to quantify the level of discrimination in a return for a given satisfactory return value. As returns are uncertain, stock returns are considered triangular fuzzy numbers. Stock price data from the Bombay Stock Exchange are used to illustrate the effectiveness of the proposed model. The solutions are done by genetic algorithms.

  18. Discrete Spectral Transformations of Skew Orthogonal Polynomials and Associated Discrete Integrable Systems

    Directory of Open Access Journals (Sweden)

    Hiroshi Miki

    2012-02-01

    Full Text Available Discrete spectral transformations of skew orthogonal polynomials are presented. From these spectral transformations, it is shown that the corresponding discrete integrable systems are derived both in 1+1 dimension and in 2+1 dimension. Especially in the (2+1-dimensional case, the corresponding system can be extended to 2×2 matrix form. The factorization theorem of the Christoffel kernel for skew orthogonal polynomials in random matrix theory is presented as a by-product of these transformations.

  19. The Use of the Skew T, Log P Diagram in Analysis and Forecasting. Revision

    Science.gov (United States)

    1990-03-01

    65 O 006 6063 10 1i 0 i 6 110 I1 FA*RtNEPIT TEMPCRATUX( SCALE Figure 3. Isatherms an the Skew-T Chert. in parts of water vapor per 1000 parts of dry...2 no 1000200 .p 47, 46 46 so III U $3 04 UT so s7 U 0s s .o es so t5 10050 Figure 7. Ttcdmm Socoles an Owe Skew-T Churt. * 2-7 0* ~ ~ ~ ~~~V orj or

  20. Correction for Rhiel's theory for the range estimator of the coefficient of variation for skewed distributions.

    Science.gov (United States)

    Rhiel, G Steven

    2010-02-01

    In 2007, Rhiel presented a technique to estimate the coefficient of variation from the range when sampling from skewed distributions. To provide an unbiased estimate, a correction factor (a(n)) for the mean was included. Numerical correction factors for a number of skewed distributions were provided. In a follow-up paper, he provided a proof he claimed showed the correction factor was independent of the mean and standard deviation, making the factors useful as these parameters vary; however, that proof did not establish independence. Herein is a proof which establishes the independence.

  1. Large-scale genomic 2D visualization reveals extensive CG-AT skew correlation in bird genomes

    Directory of Open Access Journals (Sweden)

    Deng Xuemei

    2007-11-01

    Full Text Available Abstract Background Bird genomes have very different compositional structure compared with other warm-blooded animals. The variation in the base skew rules in the vertebrate genomes remains puzzling, but it must relate somehow to large-scale genome evolution. Current research is inclined to relate base skew with mutations and their fixation. Here we wish to explore base skew correlations in bird genomes, to develop methods for displaying and quantifying such correlations at different scales, and to discuss possible explanations for the peculiarities of the bird genomes in skew correlation. Results We have developed a method called Base Skew Double Triangle (BSDT for exhibiting the genome-scale change of AT/CG skew as a two-dimensional square picture, showing base skews at many scales simultaneously in a single image. By this method we found that most chicken chromosomes have high AT/CG skew correlation (symmetry in 2D picture, except for some microchromosomes. No other organisms studied (18 species show such high skew correlations. This visualized high correlation was validated by three kinds of quantitative calculations with overlapping and non-overlapping windows, all indicating that chicken and birds in general have a special genome structure. Similar features were also found in some of the mammal genomes, but clearly much weaker than in chickens. We presume that the skew correlation feature evolved near the time that birds separated from other vertebrate lineages. When we eliminated the repeat sequences from the genomes, the AT and CG skews correlation increased for some mammal genomes, but were still clearly lower than in chickens. Conclusion Our results suggest that BSDT is an expressive visualization method for AT and CG skew and enabled the discovery of the very high skew correlation in bird genomes; this peculiarity is worth further study. Computational analysis indicated that this correlation might be a compositional characteristic

  2. 75 FR 59681 - Trade Adjustment Assistance for Farmers

    Science.gov (United States)

    2010-09-28

    ... Foreign Agricultural Service Trade Adjustment Assistance for Farmers AGENCY: Foreign Agricultural Service... Farmers Program Review Committee, comprised of representatives from USDA's Office of the Chief Economist... adjustment assistance in FY 2011. FOR FURTHER INFORMATION CONTACT: Trade Adjustment Assistance for...

  3. Genotype and phenotype in Klinefelter syndrome - impact of androgen receptor polymorphism and skewed X inactivation

    DEFF Research Database (Denmark)

    Bojesen, A; Hertz, J M; Gravholt, C H

    2011-01-01

    The phenotypic variation of Klinefelter syndrome (KS) is wide and may by caused by various genetic and epigenetic effects. Skewed inactivation of the supra-numerical X chromosome and polymorphism in the androgen receptor (AR) have been suggested as plausible causes. We wanted to describe X...

  4. The curious anomaly of skewed judgment distributions and systematic error in the wisdom of crowds.

    Directory of Open Access Journals (Sweden)

    Ulrik W Nash

    Full Text Available Judgment distributions are often skewed and we know little about why. This paper explains the phenomenon of skewed judgment distributions by introducing the augmented quincunx (AQ model of sequential and probabilistic cue categorization by neurons of judges. In the process of developing inferences about true values, when neurons categorize cues better than chance, and when the particular true value is extreme compared to what is typical and anchored upon, then populations of judges form skewed judgment distributions with high probability. Moreover, the collective error made by these people can be inferred from how skewed their judgment distributions are, and in what direction they tilt. This implies not just that judgment distributions are shaped by cues, but that judgment distributions are cues themselves for the wisdom of crowds. The AQ model also predicts that judgment variance correlates positively with collective error, thereby challenging what is commonly believed about how diversity and collective intelligence relate. Data from 3053 judgment surveys about US macroeconomic variables obtained from the Federal Reserve Bank of Philadelphia and the Wall Street Journal provide strong support, and implications are discussed with reference to three central ideas on collective intelligence, these being Galton's conjecture on the distribution of judgments, Muth's rational expectations hypothesis, and Page's diversity prediction theorem.

  5. Influence of Slope and Slenderness Ratio on the Non-Column Volume in Skew Rolling

    Institute of Scientific and Technical Information of China (English)

    Yongqiang KANG; Zhenghuan HU; Jinping LIU; Cuiping YANG; Huiping DU

    2003-01-01

    A definition of non-column volume ratio (NCVR) is brought forward by the authors. It is influenced greatly by the slendernessratio of the cylindrical billet and the slope of the wedge on the tool of skew rolling. Using the numerical simulation, the lawof

  6. Finite Element Studies on Free Vibration of Laminated Composite Cylindrical Skew Panels

    Directory of Open Access Journals (Sweden)

    Srinivasa Chikkol Venkateshappa

    2014-01-01

    Full Text Available This paper presents the finite element studies made on free vibration of isotropic and laminated composite cylindrical skew panels. A finite element analysis is performed using CQUAD4 and CQUAD8 elements of MSC/NASTRAN software. The effects of the panel angle, skew angle, aspect ratio, and length-to-thickness-ratio on fundamental natural frequency of vibration of isotropic cylindrical skew panels are studied. The effects of additional parameters such as fiber orientation angle, numbers of layers (keeping total thickness constant, and laminate stacking sequence on the fundamental frequency of vibration of antisymmetric composite laminates have also been studied. During validation and convergence study, it is found that the CQUAD8 element yields more accurate results than the CQUAD4 element. Hence the CQUAD8 element has been employed for the remaining part of the investigation. The fundamental frequency is found to increase with the panel angle and skew angle. The variation of the fundamental frequency with the number of layers is not appreciable when the number of layers is greater than about 6. It is also seen that the boundary conditions have significant influence on the fundamental frequency.

  7. Development of a Skewed Pipe Shear Connector for Precast Concrete Structures.

    Science.gov (United States)

    Kim, Sang-Hyo; Choi, Jae-Gu; Park, Sejun; Lee, Hyunmin; Heo, And Won-Ho

    2017-05-13

    Joint connection methods, such as shear key and loop bar, improve the structural performance of precast concrete structures; consequently, there is usually decreased workability or constructional efficiency. This paper proposes a high-efficiency skewed pipe shear connector. To resist shear and pull-out forces, the proposed connectors are placed diagonally between precast concrete segments and a cast-in-place concrete joint part on a girder. Design variables (such as the pipe diameter, length, and insertion angle) have been examined to investigate the connection performance of the proposed connector. The results of our testing indicate that the skewed pipe shear connectors have 50% higher ductility and a 15% higher ratio of maximum load to yield strength as compared to the corresponding parameters of the loop bar. Finite element analysis was used for validation. The resulting validation indicates that, compared to the loop bar, the skewed pipe shear connector has a higher ultimate shear and pull-out resistance. These results indicate that the skewed pipe shear connector demonstrates more idealized behavior than the loop bar in precast concrete structures.

  8. Robust Runtime Optimization and Skew-Resistant Execution of Analytical SPARQL Queries on Pig

    NARCIS (Netherlands)

    Kotoulas, S; Urbani, J.; Boncz, P.A.; Mika, P.

    2012-01-01

    We describe a system that incrementally translates SPARQL queries to Pig Latin and executes them on a Hadoop cluster. This system is designed to work eciently on complex queries with many self-joins over huge datasets, avoiding job failures even in the case of joins with unexpected high-value skew.

  9. Consistent paternity skew through ontogeny in Peron's tree frog (Litoria peronii.

    Directory of Open Access Journals (Sweden)

    Craig D H Sherman

    Full Text Available BACKGROUND: A large number of studies in postcopulatory sexual selection use paternity success as a proxy for fertilization success. However, selective mortality during embryonic development can lead to skews in paternity in situations of polyandry and sperm competition. Thus, when assessment of paternity fails to incorporate mortality skews during early ontogeny, this may interfere with correct interpretation of results and subsequent evolutionary inference. In a previous series of in vitro sperm competition experiments with amphibians (Litoria peronii, we showed skewed paternity patterns towards males more genetically similar to the female. METHODOLOGY/PRINCIPAL FINDINGS: Here we use in vitro fertilizations and sperm competition trials to test if this pattern of paternity of fully developed tadpoles reflects patterns of paternity at fertilization and if paternity skews changes during embryonic development. We show that there is no selective mortality through ontogeny and that patterns of paternity of hatched tadpoles reflects success of competing males in sperm competition at fertilization. CONCLUSIONS/SIGNIFICANCE: While this study shows that previous inferences of fertilization success from paternity data are valid for this species, rigorous testing of these assumptions is required to ensure that differential embryonic mortality does not confound estimations of true fertilization success.

  10. Influence of pressure gradient on streamwise skewness factor in turbulent boundary layer

    Science.gov (United States)

    Dróżdż, Artur

    2014-08-01

    The paper shows an effect of favourable and adverse pressure gradients on turbulent boundary layer. The skewness factor of streamwise velocity component was chosen as a measure of the pressure gradient impact. It appears that skewness factor is an indicator of convection velocity of coherent structures, which is not always equal to the average flow velocity. The analysis has been performed based upon velocity profiles measured with hot-wire technique in turbulent boundary layer with pressure gradient corresponding to turbomachinery conditions. The results show that the skewness factor decreases in the flow region subjected to FPG and increases in the APG conditions. The changes of convection velocity and skewness factor are caused by influence of large-scale motion through the mechanism called amplitude modulation. The large-scale motion is less active in FPG and more active in APG, therefore in FPG the production of vortices is random (there are no high and low speed regions), while in the APG the large-scale motion drives the production of vortices. Namely, the vortices appear only in the high-speed regions, therefore have convection velocity higher than local mean velocity. The convection velocity affects directly the turbulent sweep and ejection events. The more flow is dominated by large-scale motion the higher values takes both the convection velocity of small-scale structures and sweep events induced by them.

  11. Large-scale age-dependent skewed sex ratio in a sexually dimorphic avian scavenger.

    Directory of Open Access Journals (Sweden)

    Sergio A Lambertucci

    Full Text Available Age-dependent skewed sex ratios have been observed in bird populations, with adult males generally outnumbering females. This trend is mainly driven by higher female mortality, sometimes associated with anthropogenic factors. Despite the large amount of work on bird sex ratios, research examining the spatial stability of adult sex ratios is extremely scarce. The Andean condor (Vultur gryphus is the only bird of prey with strong sexual dimorphism favouring males (males are 30% heavier than females. By examining data from most of its South-American range, we show that while the juvenile sex ratio is balanced, or even female-skewed, the sex ratio becomes increasing male-skewed with age, with adult males outnumbering females by >20%, and, in some cases by four times more. This result is consistent across regions and independent of the nature of field data. Reasons for this are unknown but it can be hypothesized that the progressive disappearance of females may be associated with mortality caused by anthropogenic factors. This idea is supported by the asymmetric habitat use by the two sexes, with females scavenging in more humanized areas. Whatever the cause, male-skewed adult sex ratios imply that populations of this endangered scavenger face higher risks of extinction than previously believed.

  12. Large-scale age-dependent skewed sex ratio in a sexually dimorphic avian scavenger.

    Science.gov (United States)

    Lambertucci, Sergio A; Carrete, Martina; Donázar, José Antonio; Hiraldo, Fernando

    2012-01-01

    Age-dependent skewed sex ratios have been observed in bird populations, with adult males generally outnumbering females. This trend is mainly driven by higher female mortality, sometimes associated with anthropogenic factors. Despite the large amount of work on bird sex ratios, research examining the spatial stability of adult sex ratios is extremely scarce. The Andean condor (Vultur gryphus) is the only bird of prey with strong sexual dimorphism favouring males (males are 30% heavier than females). By examining data from most of its South-American range, we show that while the juvenile sex ratio is balanced, or even female-skewed, the sex ratio becomes increasing male-skewed with age, with adult males outnumbering females by >20%, and, in some cases by four times more. This result is consistent across regions and independent of the nature of field data. Reasons for this are unknown but it can be hypothesized that the progressive disappearance of females may be associated with mortality caused by anthropogenic factors. This idea is supported by the asymmetric habitat use by the two sexes, with females scavenging in more humanized areas. Whatever the cause, male-skewed adult sex ratios imply that populations of this endangered scavenger face higher risks of extinction than previously believed.

  13. Skewness and Kurtosis as Applied to a Portfolio in the Korean Stock Market

    Science.gov (United States)

    Ahn, Tae-Sung

    2009-04-01

    A well diversified portfolio is critical to prudent investment in a stock market. To lessen risk in a volatile market, portfolios should minimize dispersion. This paper analyzes skewness and kurtosis of businesses listed on Korean stock markets, e.g., KOSPI and KOSDAQ. It looks at distribution using the Gauss function, and examines how mean and variance can be applied in building a portfolio.

  14. Parentage, reproductive skew and queen turnover in a multiple-queen ant analysed with microsatellites.

    Science.gov (United States)

    Bourke, A F; Green, H A; Bruford, M W

    1997-02-22

    We investigated the fine genetic structure of colonies of the ant, Leptothorax acervorum, to examine how queens share parentage (skew) in a social insect with multiple queens (polygyny). Overall, 494 individuals from eight polygynous field colonies were typed at up to seven microsatellite loci each. The first main finding was that surprisingly many sexual progeny (60% of young queens and 49% of young males) were not the offspring of the extant queens within their colonies. This implies that a high turnover (brief reproductive lifespan) of queens within colonies could be an important feature of polygyny. The second main result was that in most colonies relatedness among sexual progeny fell significantly below that expected among full siblings, proving that these progeny were produced by more than one singly-mated queen, but that skew in two colonies where the data permitted its calculation was moderate to high. However, relative to a German population, the study population is characterized by low queen-queen relatedness and low skew in female production, which is in line with the predictions of skew theory.

  15. Generalized Christoffel-Darboux formula for skew-orthogonal polynomials and random matrix theory

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Saugata [Abdus Salam ICTP, Strada Costiera 11, 34100, Trieste (Italy)

    2006-07-14

    We obtain a generalized Christoffel-Darboux (GCD) formula for skew-orthogonal polynomials. Using this, we present an alternative derivation of the level density and two-point function for Gaussian orthogonal ensembles and Gaussian symplectic ensembles of random matrices.

  16. Subordinate wasps are more aggressive in colonies with low reproductive skew

    DEFF Research Database (Denmark)

    Fanelli, D.; Boomsma, Jacobus Jan; Turillazzi, S.

    2008-01-01

    The small societies of primitively eusocial wasps have provided interesting testing grounds for reproductive skew theory because all individuals have similar reproductive potential, which is unusual in social insects but common in vertebrate societies. Aggression is a key parameter in testing the...

  17. Dirac structures and boundary control systems associated with skew-symmetric differential operators

    NARCIS (Netherlands)

    Le Gorrec, Y.; Zwart, H.J.; Maschke, B.

    2005-01-01

    Associated with a skew-symmetric linear operator on the spatial domain $[a,b]$ we define a Dirac structure which includes the port variables on the boundary of this spatial domain. This Dirac structure is a subspace of a Hilbert space. Naturally, associated with this Dirac structure is an infinite-d

  18. Dirac structures and boundary control systems associated with skew-symmetric differential operators

    NARCIS (Netherlands)

    Le Gorrec, Y.; Zwart, H.J.; Maschke, B.

    2004-01-01

    Associated with a skew-symmetric linear operator on the spatial domain $[a,b]$ we define a Dirac structure which includes the port variables on the boundary of this spatial domain. This Dirac structure is a subspace of a Hilbert space. Naturally, associated to this Dirac structure is infinite dimen

  19. EXPERIMENTAL RESEARCH ON AERODYNAMIC PERFORMANCE AND EXIT FLOW FIELD OF LOW PRESSURE AXIAL FLOW FAN WITH CIRCUMFERENTIAL SKEWED BLADES

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this article, the low pressure axial flow fan with circumferential skewed rotor blade, including the radial blade, the forward-skewed blade and the backward-skewed blade, was studied with experimental methods. The aerodynamic performance of the rotors was measured. At the design condition at outlet of the rotors, detailed flow measurements were performed with a five-hole probe and a Hot-Wire Anemometer (HWA). The results show that compared to the radial rotor, the forward-skewed rotor demonstrates a wider Stable Operating Range (SOR), is able to reduce the total pressure loss in the hub region and make main loading of blade accumulating in the mid-span region. There is a wider wake in the upper mid-span region of the forward-skewed rotor. Compared to the radial rotor, in the backward-skewed rotor there is higher total pressure loss near the hub and shroud regions and lower loss in the mid-span region. In addition, the velocity deficit in the wake is lower at mid-span of the backward-skewed rotor than the forward-skewed rotor.

  20. Modelling non-normal data : The relationship between the skew-normal factor model and the quadratic factor model

    NARCIS (Netherlands)

    Smits, Iris A.M.; Timmerman, Marieke E.; Stegeman, Alwin

    Maximum likelihood estimation of the linear factor model for continuous items assumes normally distributed item scores. We consider deviations from normality by means of a skew-normally distributed factor model or a quadratic factor model. We show that the item distributions under a skew-normal

  1. A novel technique for estimation of skew in binary text document images based on linear regression analysis

    Indian Academy of Sciences (India)

    P Shivakumara; G Hemantha Kumar; D S Guru; P Nagabhushan

    2005-02-01

    When a document is scanned either mechanically or manually for digitization, it often suffers from some degree of skew or tilt. Skew-angle detection plays an important role in the field of document analysis systems and OCR in achieving the expected accuracy. In this paper, we consider skew estimation of Roman script. The method uses the boundary growing approach to extract the lowermost and uppermost coordinates of pixels of characters of text lines present in the document, which can be subjected to linear regression analysis (LRA) to determine the skew angle of a skewed document. Further, the proposed technique works fine for scaled text binary documents also. The technique works based on the assumption that the space between the text lines is greater than the space between the words and characters. Finally, in order to evaluate the performance of the proposed methodology we compare the experimental results with those of well-known existing methods.

  2. Annual Adjustment Factors

    Data.gov (United States)

    Department of Housing and Urban Development — The Department of Housing and Urban Development establishes the rent adjustment factors - called Annual Adjustment Factors (AAFs) - on the basis of Consumer Price...

  3. Bed slope effects on turbulent wave boundary layers: 2. Comparison with skewness, asymmetry, and other effects

    DEFF Research Database (Denmark)

    Fuhrman, David R.; Fredsøe, Jørgen; Sumer, B. Mutlu

    2009-01-01

    contributions believed to play a prominent role in cross-shore boundary layer and sediment transport processes: (1) converging-diverging effects from bed slope, (2) wave skewness, (3) wave asymmetry, and (4) waves combined with superposed negative currents (intended to loosely represent, for example, return...... currents or undertow). The effects from each of the four components are isolated and quantified using a standard set of bed shear stress quantities, allowing their easy comparison. For conditions representing large shallow-water waves on steep slopes, the results suggest that converging-diverging effects...... from beach slope may make a significant onshore bed load contribution. Generally, however, the results suggest wave skewness (in addition to conventional steady streaming) as the most important onshore contribution outside the surf zone. Streaming induced within the wave boundary layer is also...

  4. Muon Tracking Studies in a Skew Parametric Resonance Ionization Cooling Channel

    Energy Technology Data Exchange (ETDEWEB)

    Sy, Amy [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Afanaciev, Andre [George Washington Univ., Washington, DC (United States); Derbenev, Yaroslav S. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Johnson, Rolland [Muons, Inc., Batavia, IL (United States); Morozov, Vasiliy [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2015-09-01

    Skew Parametric-resonance Ionization Cooling (SPIC) is an extension of the Parametric-resonance Ionization Cooling (PIC) framework that has previously been explored as the final 6D cooling stage of a high-luminosity muon collider. The addition of skew quadrupoles to the PIC magnetic focusing channel induces coupled dynamic behavior of the beam that is radially periodic. The periodicity of the radial motion allows for the avoidance of unwanted resonances in the horizontal and vertical transverse planes, while still providing periodic locations at which ionization cooling components can be implemented. A first practical implementation of the magnetic field components required in the SPIC channel is modeled in MADX. Dynamic features of the coupled correlated optics with and without induced parametric resonance are presented and discussed.

  5. Multi-objective mean-variance-skewness model for generation portfolio allocation in electricity markets

    Energy Technology Data Exchange (ETDEWEB)

    Pindoriya, N.M.; Singh, S.N. [Department of Electrical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Singh, S.K. [Indian Institute of Management Lucknow, Lucknow 226013 (India)

    2010-10-15

    This paper proposes an approach for generation portfolio allocation based on mean-variance-skewness (MVS) model which is an extension of the classical mean-variance (MV) portfolio theory, to deal with assets whose return distribution is non-normal. The MVS model allocates portfolios optimally by considering the maximization of both the expected return and skewness of portfolio return while simultaneously minimizing the risk. Since, it is competing and conflicting non-smooth multi-objective optimization problem, this paper employed a multi-objective particle swarm optimization (MOPSO) based meta-heuristic technique to provide Pareto-optimal solution in a single simulation run. Using a case study of the PJM electricity market, the performance of the MVS portfolio theory based method and the classical MV method is compared. It has been found that the MVS portfolio theory based method can provide significantly better portfolios in the situation where non-normally distributed assets exist for trading. (author)

  6. Research on the optimal structure configuration of dither RLG used in skewed redundant INS

    Science.gov (United States)

    Gao, Chunfeng; Wang, Qi; Wei, Guo; Long, Xingwu

    2016-05-01

    The actual combat effectiveness of weapon equipment is restricted by the performance of Inertial Navigation System (INS), especially in high reliability required situations such as fighter, satellite and submarine. Through the use of skewed sensor geometries, redundant technique has been applied to reduce the cost and improve the reliability of the INS. In this paper, the structure configuration and the inertial sensor characteristics of Skewed Redundant Strapdown Inertial Navigation System (SRSINS) using dithered Ring Laser Gyroscope (RLG) are analyzed. For the dither coupling effects of the dither gyro, the system measurement errors can be amplified either the individual gyro dither frequency is near one another or the structure of the SRSINS is unreasonable. Based on the characteristics of RLG, the research on coupled vibration of dithered RLG in SRSINS is carried out. On the principle of optimal navigation performance, optimal reliability and optimal cost-effectiveness, the comprehensive evaluation scheme of the inertial sensor configuration of SRINS is given.

  7. Semiparametric Bayesian inference on skew-normal joint modeling of multivariate longitudinal and survival data.

    Science.gov (United States)

    Tang, An-Min; Tang, Nian-Sheng

    2015-02-28

    We propose a semiparametric multivariate skew-normal joint model for multivariate longitudinal and multivariate survival data. One main feature of the posited model is that we relax the commonly used normality assumption for random effects and within-subject error by using a centered Dirichlet process prior to specify the random effects distribution and using a multivariate skew-normal distribution to specify the within-subject error distribution and model trajectory functions of longitudinal responses semiparametrically. A Bayesian approach is proposed to simultaneously obtain Bayesian estimates of unknown parameters, random effects and nonparametric functions by combining the Gibbs sampler and the Metropolis-Hastings algorithm. Particularly, a Bayesian local influence approach is developed to assess the effect of minor perturbations to within-subject measurement error and random effects. Several simulation studies and an example are presented to illustrate the proposed methodologies.

  8. Optimization Design and Experimental Study of Low-Pressure Axial Fan with Forward-Skewed Blades

    Directory of Open Access Journals (Sweden)

    Li Yang

    2007-01-01

    Full Text Available This paper presents an experimental study of the optimization of blade skew in low pressure axial fan. Using back propagation (BP neural network and genetic algorithm (GA, the optimization was performed for a radial blade. An optimized blade is obtained through blade forward skew. Measurement of the two blades was carried out in aerodynamic and aeroacoustic performance. Compared to the radial blade, the optimized blade demonstrated improvements in efficiency, total pressure ratio, stable operating range, and aerodynamic noise. Detailed flow measurement was performed in outlet flow field for investigating the responsible flow mechanisms. The optimized blade can cause a spanwise redistribution of flow toward the blade midspan and reduce tip loading. This results in reduced significantly total pressure loss near hub and shroud endwall region, despite the slight increase of total pressure loss at midspan. In addition, the measured spectrums show that the broadband noise of the impeller is dominant.

  9. Skew ray tracing in a step-index optical fiber using Geometric Algebra

    CERN Document Server

    Ang, Angeleene; McNamara, Daniel J

    2015-01-01

    We used Geometric Algebra to compute the paths of skew rays in a cylindrical, step-index multimode optical fiber. To do this, we used the vector addition form for the law of propagation, the exponential of an imaginary vector form for the law of refraction, and the juxtaposed vector product form for the law of reflection. In particular, the exponential forms of the vector rotations enables us to take advantage of the addition or subtraction of exponential arguments of two rotated vectors in the derivation of the ray tracing invariants in cylindrical and spherical coordinates. We showed that the light rays inside the optical fiber trace a polygonal helical path characterized by three invariants that relate successive reflections inside the fiber: the ray path distance, the difference in axial distances, and the difference in the azimuthal angles. We also rederived the known generalized formula for the numerical aperture for skew rays, which simplifies to the standard form for meridional rays.

  10. SKEWNESS IN STOCK RETURNS: EVIDENCE FROM THE BUCHAREST STOCK EXCHANGE DURING 2000 – 2011

    Directory of Open Access Journals (Sweden)

    IULIAN PANAIT

    2012-05-01

    Full Text Available Our paper investigates the symmetry in stock returns of the 30 most liquid companies traded on Bucharest Stock Exchange during 2000 – 2011 and also the most representative 5 market indices. Our daily data shows that skewness estimates are slightly negative for most indices and individual stocks, but only a few present values significantly different from the characteristics of a normal distribution. We compare our results with skewness estimates for 21 major and emerging stock market indices around the world and find that such results are similar to other low capitalization and trading volume markets. For all the Romanian and international assets studied, the Studentized-Range (St-R and Jarque-Bera (J-B tests reject the hypothesis of normal distribution of daily returns.

  11. Measuring skewness of red blood cell deformability distribution by laser ektacytometry

    Energy Technology Data Exchange (ETDEWEB)

    Nikitin, S Yu; Priezzhev, A V; Lugovtsov, A E [International Laser Center, M. V. Lomonosov Moscow State University, Moscow (Russian Federation); Ustinov, V D [M. V. Lomonosov Moscow State University, Faculty of Computational Mathematics and Cybernetics, Moscow (Russian Federation)

    2014-08-31

    An algorithm is proposed for measuring the parameters of red blood cell deformability distribution based on laser diffractometry of red blood cells in shear flow (ektacytometry). The algorithm is tested on specially prepared samples of rat blood. In these experiments we succeeded in measuring the mean deformability, deformability variance and skewness of red blood cell deformability distribution with errors of 10%, 15% and 35%, respectively. (laser biophotonics)

  12. On the skew-bounded minimum-buffer routing tree problem

    OpenAIRE

    Albrecht, C.; Kahng, A B; Liu, B.; Mandoiu, Ion I.; Zelikovsky, A Z

    2003-01-01

    Bounding the load capacitance at gate outputs is a standard element in today's electrical correctness methodologies for high-speed digital very large scale integration design. Bounds on load caps improve coupling-noise immunity, reduce degradation of signal transition edges, and reduce delay uncertainty due to coupling noise (Kahng et al. 1998). For clock and test distribution, an additional design requirement is bounding the buffer skew, i.e., the difference between the maximum and the minim...

  13. Expanding the mission plan for large scale telescope systems via skew path optical conditioners

    Science.gov (United States)

    Savastinuk, John; Palmer, Troy A.; Alexay, Christopher

    2017-05-01

    We describe a case study in which a telescope system, originally designed for a large format, visible camera, needed MWIR imaging capabilities while maintaining its original setup. The dedicated telescope system was adapted to share its existing optics with a new imaging module via a skew path concept. The challenges of non-rotationally symmetric design are explored along with an explanation of the methodology used to analyze and address the unique configuration.

  14. Enhanced Skewed Load and Broadside Power Reduction in Transition Fault Testing

    Directory of Open Access Journals (Sweden)

    Mrs. A.Jyothi

    2014-10-01

    Full Text Available This Paper Proposes the T-algorithm technique to optimize the testing Skewed Load and Broadside architecture. And the architecture used to the compare the test pattern results. In this architecture, T-algorithm used to optimize the testing architecture. This architecture compare the test pattern output for the required any type of combinational architecture. The optimization process mainly focused by gate optimization for secure architecture. The proposed system to use the T-algorithm, to optimize the testing clocking level for the required test patterns. This technique to replace the flip flop and the mux arrangement. To reduce the flip flops in Skewed Load architecture. And to develop the accuracy for testing architecture. The proposed system consists of the secure testing architecture and includes the XOR-gate architecture. So the modification process applied by the Broadside and over all Skewed Load architecture. The proposed technique to check the scanning results for the testing process. The testing architecture mainly used to the error attack for the scanning process and the scanning process work with any type of testing architecture. The scanning process to be secure using the T-algorithm for the Skewed Load architecture. And to develop the testing process for the fault identification process. The diagnosis technique to detect error for the scanning process in any type combinational architecture. The T-algorithm used to reduce the circuit complexity for the testing architecture and the testing architecture used to reduce the delay level. And the future process, this technique used to reduce the gate level for the sticky comparator architecture and to modify the clocking function for the testing process. This technique to develop the accuracy level for the testing process compare to the present methodology.

  15. Dimension and measure of baker-like skew-products of $\\beta$-transformations

    CERN Document Server

    Färm, David

    2010-01-01

    We consider a generalisation of the baker's transformation, consisting of a skew-product of contractions and a $\\beta$-transformation. The Hausdorff dimension and Lebesgue measure of the attractor is calculated for a set of parameters with positive measure. The proofs use a new transverality lemma similar to Solomyak's [Solomyak, 1995]. This transversality, which is applicable to the considered class of maps holds for a larger set of parameters than Solomyak's transversality.

  16. Slow shocks and conduction fronts from Petschek reconnection of skewed magnetic fields: two-fluid effects

    CERN Document Server

    Longcope, D W

    2010-01-01

    In models of fast magnetic reconnection, flux transfer occurs within a small portion of a current sheet triggering stored magnetic energy to be thermalized by shocks. When the initial current sheet separates magnetic fields which are not perfectly anti-parallel, i.e. they are skewed, magnetic energy is first converted to bulk kinetic energy and then thermalized in slow magnetosonic shocks. We show that the latter resemble parallel shocks or hydrodynamic shocks for all skew angles except those very near the anti-parallel limit. As for parallel shocks, the structures of reconnection-driven slow shocks are best studied using two-fluid equations in which ions and electrons have independent temperature. Time-dependent solutions of these equations can be used to predict and understand the shocks from reconnection of skewed magnetic fields. The results differ from those found using a single-fluid model such as magnetohydrodynamics. In the two-fluid model electrons are heated indirectly and thus carry a heat flux alw...

  17. A Bayesian estimate of the concordance correlation coefficient with skewed data.

    Science.gov (United States)

    Feng, Dai; Baumgartner, Richard; Svetnik, Vladimir

    2015-01-01

    Concordance correlation coefficient (CCC) is one of the most popular scaled indices used to evaluate agreement. Most commonly, it is used under the assumption that data is normally distributed. This assumption, however, does not apply to skewed data sets. While methods for the estimation of the CCC of skewed data sets have been introduced and studied, the Bayesian approach and its comparison with the previous methods has been lacking. In this study, we propose a Bayesian method for the estimation of the CCC of skewed data sets and compare it with the best method previously investigated. The proposed method has certain advantages. It tends to outperform the best method studied before when the variation of the data is mainly from the random subject effect instead of error. Furthermore, it allows for greater flexibility in application by enabling incorporation of missing data, confounding covariates, and replications, which was not considered previously. The superiority of this new approach is demonstrated using simulation as well as real-life biomarker data sets used in an electroencephalography clinical study. The implementation of the Bayesian method is accessible through the Comprehensive R Archive Network.

  18. Free vibration of composite skewed cylindrical shell panel by finite element method

    Science.gov (United States)

    Haldar, Salil

    2008-03-01

    In this paper a composite triangular shallow shell element has been used for free vibration analysis of laminated composite skewed cylindrical shell panels. In the present element first-order shear deformation theory has been incorporated by taking transverse displacement and bending rotations as independent field variables. The interpolation function used to approximate transverse displacement is one order higher than for bending rotations. This has made the element free from locking in shear. Two types of mass lumping schemes have been recommended. In one of the mass lumping scheme the effect of rotary inertia has been incorporated in the element formulations. Free vibration of skewed composite cylindrical shell panels having different thickness to radius ratios ( h/R=0.01-0.2), length to radius ratios ( L/R), number of layers and fiber orientation angles have been analyzed following the shallow shell method. The results for few examples obtained in the present analysis have compared with the published results. Some new results of composite skewed cylindrical shell panels have been presented which are expected to be useful to future research in this direction.

  19. Aberration compensation in a Skew parametric-resonance ionization cooling channel

    Energy Technology Data Exchange (ETDEWEB)

    Sy, Amy V. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Derbenev, Yaroslav S. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Morozov, Vasiliy [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Afanasev, Andrei [George Washington Univ., Washington, DC (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Bao, Y. [Univ. of California, Riverside, CA (United States); Johnson, Rolland P. [Muons Inc., Batavia, IL (United States)

    2017-05-01

    Skew Parametric-resonance Ionization Cooling (Skew PIC) represents a novel method for focusing of highly divergent particle beams, as in the final 6D cooling stage of a high-luminosity muon collider. In the muon collider concept, the resultant equilibrium transverse emittances from cooling with Skew PIC are an order of magnitude smaller than in conventional ionization cooling. The concept makes use of coupling of the transverse dynamic behavior, and the linear dynamics are well-behaved with good agreement between analytic solutions and simulation results. Compared to the uncoupled system, coupling of the transverse dynamic behavior purports to reduce the number of multipoles required for aberration compensation while also avoiding unwanted resonances. Aberration compensation is more complicated in the coupled case, especially in the high-luminosity muon collider application where equilibrium angular spreads in the cooling channel are on the order of 200 mrad. We present recent progress on aberration compensation for control of highly divergent muon beams in the coupled correlated optics channel, and a simple cooling model to test the transverse acceptance of the channel.

  20. Buffeting response of long-span cable-supported bridges under skew winds. Part 1: theory

    Science.gov (United States)

    Zhu, L. D.; Xu, Y. L.

    2005-03-01

    A finite-element-based framework for buffeting analysis of long-span cable-supported bridges under skew winds is developed in the frequency domain utilizing the linear quasi-steady theory and the strip theory of aerodynamics in conjunction with the pseudo excitation method. A set of universal expressions for six components of buffeting forces is first derived in association with oblique cross-sections of bridge components, in which the buffeting forces are formed with respect to the wind coordinate system and then converted to those with respect to the structural coordinate system. Skew mean wind and three orthogonal components of velocity fluctuations can thus be easily handled without any further decomposition. The coherence between velocity fluctuations of wind turbulence at any two arbitrary spatial points is considered in the global wind coordinate system rather than in the global structural coordinate system. Aeroelastic stiffness and damping matrices due to self-excited forces are then taken into consideration in terms of the 18 flutter derivatives with respect to the oblique cross-sections. The pseudo-excitation method is finally employed to solve efficiently the fully coupled 3D buffeting problem of long-span cable-supported bridges under skew winds with the effects of multi-modes and spatial modes, inter-mode coupling and aerodynamic coupling, and the interaction among major bridge components being naturally included.

  1. TVD differencing on three-dimensional unstructured meshes with monotonicity-preserving correction of mesh skewness

    Science.gov (United States)

    Denner, Fabian; van Wachem, Berend G. M.

    2015-10-01

    Total variation diminishing (TVD) schemes are a widely applied group of monotonicity-preserving advection differencing schemes for partial differential equations in numerical heat transfer and computational fluid dynamics. These schemes are typically designed for one-dimensional problems or multidimensional problems on structured equidistant quadrilateral meshes. Practical applications, however, often involve complex geometries that cannot be represented by Cartesian meshes and, therefore, necessitate the application of unstructured meshes, which require a more sophisticated discretisation to account for their additional topological complexity. In principle, TVD schemes are applicable to unstructured meshes, however, not all the data required for TVD differencing is readily available on unstructured meshes, and the solution suffers from considerable numerical diffusion as a result of mesh skewness. In this article we analyse TVD differencing on unstructured three-dimensional meshes, focusing on the non-linearity of TVD differencing and the extrapolation of the virtual upwind node. Furthermore, we propose a novel monotonicity-preserving correction method for TVD schemes that significantly reduces numerical diffusion caused by mesh skewness. The presented numerical experiments demonstrate the importance of accounting for the non-linearity introduced by TVD differencing and of imposing carefully chosen limits on the extrapolated virtual upwind node, as well as the efficacy of the proposed method to correct mesh skewness.

  2. Estimation of flood discharges at selected annual exceedance probabilities for unregulated, rural streams in Vermont, with a section on Vermont regional skew regression

    Science.gov (United States)

    Olson, Scott A.; with a section by Veilleux, Andrea G.

    2014-01-01

    This report provides estimates of flood discharges at selected annual exceedance probabilities (AEPs) for streamgages in and adjacent to Vermont and equations for estimating flood discharges at AEPs of 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent (recurrence intervals of 2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-years, respectively) for ungaged, unregulated, rural streams in Vermont. The equations were developed using generalized least-squares regression. Flood-frequency and drainage-basin characteristics from 145 streamgages were used in developing the equations. The drainage-basin characteristics used as explanatory variables in the regression equations include drainage area, percentage of wetland area, and the basin-wide mean of the average annual precipitation. The average standard errors of prediction for estimating the flood discharges at the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent AEP with these equations are 34.9, 36.0, 38.7, 42.4, 44.9, 47.3, 50.7, and 55.1 percent, respectively. Flood discharges at selected AEPs for streamgages were computed by using the Expected Moments Algorithm. To improve estimates of the flood discharges for given exceedance probabilities at streamgages in Vermont, a new generalized skew coefficient was developed. The new generalized skew for the region is a constant, 0.44. The mean square error of the generalized skew coefficient is 0.078. This report describes a technique for using results from the regression equations to adjust an AEP discharge computed from a streamgage record. This report also describes a technique for using a drainage-area adjustment to estimate flood discharge at a selected AEP for an ungaged site upstream or downstream from a streamgage. The final regression equations and the flood-discharge frequency data used in this study will be available in StreamStats. StreamStats is a World Wide Web application providing automated regression-equation solutions for user-selected sites on streams.

  3. Analysis of skewed GPS position estimates: Effects of coupling local topography and atmospheric conditions

    Science.gov (United States)

    Materna, K.; Herring, T.

    2013-12-01

    Error in modeling atmospheric delay is one of the limiting factors in the accuracy of GPS position determination. In regions with uneven topography, atmospheric delay phenomena can be especially complicated. Current delay models used in analyzing daily GPS data from the Plate Boundary Observatory (PBO) are successful in achieving millimeter-level accuracy at most locations; however, at a subset of stations, the time-series for position estimates contain an unusually large number of outliers. In many cases these outliers are oriented in the same direction. The stations which exhibit asymmetric outliers occur in various places across the PBO network, but they are especially numerous in California's Mammoth Lakes region, which served as a case study for this presentation. The phenomenon was analyzed by removing secular trends and variations with periods longer than 75 days from the signal using a median filter. We subsequently calculated the skewness of the station position residuals in north, east and up directions. In the cases examined, typical position outliers are 5-15 mm. In extreme cases, skewed position residuals, not related to snow on antennas, can be as large as 20 mm. We examine the causes of the skewness through site-by-site comparisons with topographic data and numerical weather models. Analysis suggests that the direction of the skewness is generally parallel to the local topographic gradient at a scale of several kilometers, and that outlier data points occur when certain atmospheric conditions are met. The results suggest that a coupling between the atmosphere and local topography is responsible for the phenomenon of skewed residuals. In this presentation, we examine the characteristics of the sites that we have analyzed in detail. From these analyses, we postulate possible parameterizations of the atmospheric and topographic effects that could be incorporated into geodetic analysis programs, thus allowing the inhomogeneous atmospheric delays to be

  4. Sex choice in plants: facultative adjustment of the sex ratio in the perennial herb Begonia gracilis.

    Science.gov (United States)

    López, S; Domínguez, C A

    2003-11-01

    Sex allocation theory predicts that reproducing individuals will increase their fitness by facultatively adjusting their relative investment towards the rarer sex in response to population shifts in operational sex ratio (OSR). The evolution of facultative manipulation of sex ratio depends on the ability of the parents to track the conditions favouring skewed sex allocation and on the mechanism controlling sex allocation. In animals, which have well-developed sensorial mechanisms, facultative adjustment of sex ratios has been demonstrated on many occasions. In this paper, we show that plants have mechanisms that allow them to evaluate the population OSR. We simulated three different conditions of population OSR by manipulating the amount of pollen received by the female flowers of a monoecious herb, and examined the effect of this treatment on the allocation to male vs. female flowers. A shortage of pollen on the stigmas resulted in a more male-skewed sex allocation, whereas plants that experienced a relatively pollen rich environment tended to produce a more female-skewed sex allocation pattern. Our results for Begonia gracilis demonstrate that the individuals of this species are able to respond to the levels of pollination intensity experienced by their female flowers and adjust their patterns of sex allocation in accordance to the expectations of sex allocation theory.

  5. The role of the SST-thermocline relationship in Indian Ocean Dipole skewness and its response to global warming.

    Science.gov (United States)

    Ng, Benjamin; Cai, Wenju; Walsh, Kevin

    2014-08-12

    A positive Indian Ocean Dipole (IOD) tends to have stronger cold sea surface temperature anomalies (SSTAs) over the eastern Indian Ocean with greater impacts than warm SSTAs that occur during its negative phase. Two feedbacks have been suggested as the cause of positive IOD skewness, a positive Bjerknes feedback and a negative SST-cloud-radiation (SCR) feedback, but their relative importance is debated. Using inter-model statistics, we show that the most important process for IOD skewness is an asymmetry in the thermocline feedback, whereby SSTAs respond to thermocline depth anomalies more strongly during the positive phase than negative phase. This asymmetric thermocline feedback drives IOD skewness despite positive IODs receiving greater damping from the SCR feedback. In response to global warming, although the thermocline feedback strengthens, its asymmetry between positive and negative IODs weakens. This behaviour change explains the reduction in IOD skewness that many models display under global warming.

  6. Detection of skewed X-chromosome inactivation in Fragile X syndrome and X chromosome aneuploidy using quantitative melt analysis.

    Science.gov (United States)

    Godler, David E; Inaba, Yoshimi; Schwartz, Charles E; Bui, Quang M; Shi, Elva Z; Li, Xin; Herlihy, Amy S; Skinner, Cindy; Hagerman, Randi J; Francis, David; Amor, David J; Metcalfe, Sylvia A; Hopper, John L; Slater, Howard R

    2015-07-01

    Methylation of the fragile X mental retardation 1 (FMR1) exon 1/intron 1 boundary positioned fragile X related epigenetic element 2 (FREE2), reveals skewed X-chromosome inactivation (XCI) in fragile X syndrome full mutation (FM: CGG > 200) females. XCI skewing has been also linked to abnormal X-linked gene expression with the broader clinical impact for sex chromosome aneuploidies (SCAs). In this study, 10 FREE2 CpG sites were targeted using methylation specific quantitative melt analysis (MS-QMA), including 3 sites that could not be analysed with previously used EpiTYPER system. The method was applied for detection of skewed XCI in FM females and in different types of SCA. We tested venous blood and saliva DNA collected from 107 controls (CGG chromosome test; (ii) locus-specific XCI skewing towards the hypomethylated state in FM females; and (iii) skewed XCI towards the hypermethylated state in SCA with 3 or more X chromosomes, and in 5% of the 47,XXY individuals. MS-QMA output also showed significant correlation with the EpiTYPER reference method in FM males and females (P < 0.0001) and SCAs (P < 0.05). In conclusion, we demonstrate use of MS-QMA to quantify skewed XCI in two applications with diagnostic utility.

  7. ADJUSTABLE CHIP HOLDER

    DEFF Research Database (Denmark)

    2009-01-01

    An adjustable microchip holder for holding a microchip is provided having a plurality of displaceable interconnection pads for connecting the connection holes of a microchip with one or more external devices or equipment. The adjustable microchip holder can fit different sizes of microchips with ...

  8. Benchmarking Judgmentally Adjusted Forecasts

    NARCIS (Netherlands)

    Ph.H.B.F. Franses (Philip Hans); L.P. de Bruijn (Bert)

    2017-01-01

    textabstractMany publicly available macroeconomic forecasts are judgmentally adjusted model-based forecasts. In practice, usually only a single final forecast is available, and not the underlying econometric model, nor are the size and reason for adjustment known. Hence, the relative weights given

  9. Benchmarking judgmentally adjusted forecasts

    NARCIS (Netherlands)

    Ph.H.B.F. Franses (Philip Hans); L.P. de Bruijn (Bert)

    2015-01-01

    markdownabstractMany publicly available macroeconomic forecasts are judgmentally-adjusted model-based forecasts. In practice usually only a single final forecast is available, and not the underlying econometric model, nor are the size and reason for adjustment known. Hence, the relative weights

  10. Benchmarking judgmentally adjusted forecasts

    NARCIS (Netherlands)

    Ph.H.B.F. Franses (Philip Hans); L.P. de Bruijn (Bert)

    2015-01-01

    markdownabstractMany publicly available macroeconomic forecasts are judgmentally-adjusted model-based forecasts. In practice usually only a single final forecast is available, and not the underlying econometric model, nor are the size and reason for adjustment known. Hence, the relative weights give

  11. Self-alignment of full skewed RSINS:observability analysis and full-observable Kalman filter

    Institute of Scientific and Technical Information of China (English)

    Lailiang Song; Chunxi Zhang; Jiazhen Lu

    2014-01-01

    Traditional orthogonal strapdown inertial navigation sys-tem (SINS) cannot achieve satisfactory self-alignment accuracy in the stationary base: taking more than 5 minutes and al the iner-tial sensors biases cannot get ful observability except the up-axis accelerometer. However, the ful skewed redundant SINS (RSINS) can not only enhance the reliability of the system, but also improve the accuracy of the system, such as the initial alignment. Firstly, the observability of the system state includes attitude errors and al the inertial sensors biases are analyzed with the global perspective method: any three gyroscopes and three accelerometers can be assembled into an independent subordinate SINS (sub-SINS);the system state can be uniquely confirmed by the coupling connec-tions of al the sub-SINSs;the attitude errors and random constant biases of al the inertial sensors are observable. However, the ran-dom noises of the inertial sensors are not taken into account in the above analyzing process. Secondly, the ful-observable Kalman filter which can be applied to the actual RSINS containing random noises is established; the system state includes the position, ve-locity, attitude errors of al the sub-SINSs and the random constant biases of the redundant inertial sensors. At last, the initial self-alignment process of a typical four-redundancy ful skewed RSINS is simulated: the horizontal attitudes (pitch, rol ) errors and yaw error can be exactly evaluated within 80 s and 100 s respectively, while the random constant biases of gyroscopes and accelero-meters can be precisely evaluated within 120 s. For the ful skewed RSINS, the self-alignment accuracy is greatly improved, mean-while the self-alignment time is widely shortened.

  12. Overcoming the effects of differential skewness of test items in scale construction

    Directory of Open Access Journals (Sweden)

    Johann M. Schepers

    2004-10-01

    Full Text Available The principal objective of the study was to develop a procedure for overcoming the effects of differential skewness of test items in scale construction. It was shown that the degree of skewness of test items places an upper limit on the correlations between the items, regardless of the contents of the items. If the items are ordered in terms of skewness the resulting inter correlation matrix forms a simplex or a pseudo simplex. Factoring such a matrix results in a multiplicity of factors, most of which are artifacts. A procedure for overcoming this problem was demonstrated with items from the Locus of Control Inventory (Schepers, 1995. The analysis was based on a sample of 1662 first year university students. Opsomming Die hoofdoel van die studie was om ’n prosedure te ontwikkel om die gevolge van differensiële skeefheid van toetsitems, in skaalkonstruksie, teen te werk. Daar is getoon dat die graad van skeefheid van toetsitems ’n boonste grens plaas op die korrelasies tussen die items ongeag die inhoud daarvan. Indien die items gerangskik word volgens graad van skeefheid, sal die interkorrelasiematriks van die items ’n simpleks of pseudosimpleks vorm. Indien so ’n matriks aan faktorontleding onderwerp word, lei dit tot ’n veelheid van faktore waarvan die meerderheid artefakte is. ’n Prosedure om hierdie probleem te bowe te kom, is gedemonstreer met behulp van die items van die Lokus van Beheer-vraelys (Schepers, 1995. Die ontledings is op ’n steekproef van 1662 eerstejaaruniversiteitstudente gebaseer.

  13. ON ANTI-SKEW QR CODE RECOGNITION AND ITS APPLICATION%QR码抗倾斜识别方法的研究与应用

    Institute of Scientific and Technical Information of China (English)

    付裕; 黄雅萍; 刘晓强; 宋晖; 李柏岩

    2011-01-01

    快速反应码QR(Quick Response Code)是一种信息隐藏量大且读取方便的二维标记码.由于摄像头和QR标记之间的位置关系会导致捕获生成的图像产生倾斜畸变,极大地影响识读准确率.在QR识别流程中增加倾斜矫正处理,采用空间投影校正算法实现抗倾斜的QR码识别,并将其应用到档案系统防伪识别应用,提高了QR码的识别率,取得很好的应用效果.%QR code is one kind of two-dimensional tag codes which can hide a large amount of information and is easy to read. Since the images generated from camera capturing usually have some skew distortion due to position relationship between the camera and the QR code, the precision ratio of recognition and reading is significantly impacted. In this paper we add slant correction processing to the QR recognition flow, use space projection rectification algorithm to implement anti-skew QR code recognition, and apply it in forgery prevention and recognition of archives system, so that the recognition rate of QR code is improved, and preferable application effect has been achieved.

  14. Skew-t fits to mortality data--can a Gaussian-related distribution replace the Gompertz-Makeham as the basis for mortality studies?

    Science.gov (United States)

    Clark, Jeremy S C; Kaczmarczyk, Mariusz; Mongiało, Zbigniew; Ignaczak, Paweł; Czajkowski, Andrzej A; Klęsk, Przemysław; Ciechanowicz, Andrzej

    2013-08-01

    Gompertz-related distributions have dominated mortality studies for 187 years. However, nonrelated distributions also fit well to mortality data. These compete with the Gompertz and Gompertz-Makeham data when applied to data with varying extents of truncation, with no consensus as to preference. In contrast, Gaussian-related distributions are rarely applied, despite the fact that Lexis in 1879 suggested that the normal distribution itself fits well to the right of the mode. Study aims were therefore to compare skew-t fits to Human Mortality Database data, with Gompertz-nested distributions, by implementing maximum likelihood estimation functions (mle2, R package bbmle; coding given). Results showed skew-t fits obtained lower Bayesian information criterion values than Gompertz-nested distributions, applied to low-mortality country data, including 1711 and 1810 cohorts. As Gaussian-related distributions have now been found to have almost universal application to error theory, one conclusion could be that a Gaussian-related distribution might replace Gompertz-related distributions as the basis for mortality studies.

  15. Testing gravity on large scales. The skewness of the galaxy distribution at z~1

    CERN Document Server

    Marinoni, C; Cappi, A; Le Fèvre, O; Mazure, A; Meneux, B; Pollo, A; Iovino, A; McCracken, H J; Scaramella, R; De la Torre, S; Virey, J M; Bottini, D; Garilli, B; Le Brun, V; MacCagni, D; Picat, J P; Scodeggio, M; Tresse, L; Vettolani, G; Zanichelli, A; Adami, C; Arnouts, S; Bardelli, S; Bolzonella, M; Charlot, S; Ciliegi, P; Contini, T; Foucaud, S; Franzetti, P; Gavignaud, I; Ilbert, O; Lamareille, F; Marano, B; Mathez, G; Merighi, R; Paltani, S; Pellò, R; Pozzetti, L; Radovich, M; Vergani, D; Zamorani, G; Zucca, E; Abbas, U; Bondi, M; Bongiorno, A; Brinchmann, J; Buzzi, A; Cucciati, O; de Ravel, L; Gregorini, L; Mellier, Y; Merluzzi, P; Pérez-Montero, E; Taxil, P; Temporin, S; Walcher, C J

    2008-01-01

    We study the evolution of the low-order moments of the galaxy overdensity distribution over the redshift interval 0.7skewness evolve over this redshift interval in a way that is remarkably consistent with predictions of first- and second-order perturbation theory. This finding confirms the standard gravitational instability paradigm over nearly 9 Gyrs of cosmic time and demonstrates the importance of accounting for the non-linear component of galaxy biasing to avoid disagreement between theory and observations.

  16. Identification of aeroelastic forces on twin bridge cables from full-scale measurements in skew winds

    DEFF Research Database (Denmark)

    Acampora, Antonio; Macdonald, J.H.G.; Georgakis, Christos T.;

    2012-01-01

    Despite much research in recent years, large amplitude vibrations of inclined bridge cables continue to be of concern. Various mechanisms for the excitation have been suggested, including rain-wind excitation, dry inclined cable galloping, high reduced-velocity vortex shedding and excitation from...... of this paper is to identify the aeroelastic forces for in-plane and out-of-plane vibrations of bridge cables in dry conditions as in [2], but now for skewed winds. To achieve this, an output-only system identification employing the Eigenvalue Realisation Algorithm (ERA) [3] has been applied to selected...

  17. Rings of skew polynomials and Gel'fand-Kirillov conjecture for quantum groups

    OpenAIRE

    Iohara, Kenji; Malikov, Feodor

    1993-01-01

    We introduce and study action of quantum groups on skew polynomial rings and related rings of quotients. This leads to a ``q-deformation'' of the Gel'fand-Kirillov conjecture which we partially prove. We propose a construction of automorphisms of certain non-commutaive rings of quotients coming from complex powers of quantum group generators; this is applied to explicit calculation of singular vectors in Verma modules over $U_{q}(\\gtsl_{n+1})$. We finally give a definition of a $q-$connection...

  18. Option-Based Estimation of the Price of Co-Skewness and Co-Kurtosis Risk

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Fournier, Mathieu; Fournier, Mathieu;

    -neutral second moments, and the price of co-kurtosis risk corresponds to the spread between the physical and the risk-neutral third moments. The option-based estimates of the prices of risk lead to reasonable values of the associated risk premia. An out-of-sample analysis of factor models with co-skewness and co......-kurtosis risk indicates that the new estimates of the price of risk improve the models performance. Models with higher-order market moments also robustly outperform standard competitors such as the CAPM and the Fama-French model....

  19. Option-Based Estimation of the Price of Co-Skewness and Co-Kurtosis Risk

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Fournier, Mathieu; Jacobs, Kris;

    -neutral second moments, and the price of co-kurtosis risk corresponds to the spread between the physical and the risk-neutral third moments. The option-based estimates of the prices of risk lead to reasonable values of the associated risk premia. An out-of-sample analysis of factor models with co-skewness and co......-kurtosis risk indicates that the new estimates of the price of risk improve the models' performance. Models with higher-order market moments also robustly outperform standard competitors such as the CAPM and the Fama-French model....

  20. Widely Linear Equalization for IQ Imbalance and Skew Compensation in Optical Coherent Receivers

    DEFF Research Database (Denmark)

    Porto da Silva, Edson; Zibar, Darko

    2016-01-01

    In this paper, an alternative approach to design linear equalization algorithms for optical coherent receivers is introduced. Using widely linear complex analysis, a general analytical model it is shown, where In-phase/quadrature (IQ) imbalances and IQ skew at the coherent receiver front......, it is shown that, by applying the widely linear complex analysis, one can derive a complex-valued adaptive equalizer structure which is able to compensate for linear IQ-mixing effects at the receiver front-end. By extensive numerical simulations, the performance versus complexity of the proposed equalizer...

  1. Testing Homogeneity of Mixture of Skew-normal Distributions Via Markov Chain Monte Carlo Simulation

    Directory of Open Access Journals (Sweden)

    Rahman Farnoosh Morteza Ebrahimi

    2015-05-01

    Full Text Available The main purpose of this study is to intoduce an optimal penalty function for testing homogeneity of finite mixture of skew-normal distribution based on Markov Chain Monte Carlo (MCMC simulation. In the present study the penalty function is considered as a parametric function in term of parameter of mixture models and a Baysian approach is employed to estimating the parameters of model. In order to examine the efficiency of the present study in comparison with the previous approaches, some simulation studies are presented.

  2. Skewed X-chromosome inactivation in female carriers of dyskeratosis congenita

    Energy Technology Data Exchange (ETDEWEB)

    Devriendt, K.; Matthijs, G.; Legius, E. [Univ. Hospital Gasthuisberg, Leuven (Belgium)] [and others

    1997-03-01

    In this study, we report on a family with X-linked dyskeratosis congenita (DC). Linkage analysis with markers in the factor VIII gene at Xq28 yielded a LOD score of 2 at a recombination of 0. Clinical manifestations of DC, such as skin lesions following the Blaschko lines, were present in two obligate carrier females. Highly skewed X inactivation was observed in white blood cells, cultured skin fibroblasts, and buccal mucosa from female carriers of DC in this family. This suggests a critical role for the DC gene in bone marrow-cell and fibroblast-cell proliferation. 23 refs., 4 figs., 1 tab.

  3. Stability of a cantilevered skew inhomogeneous plate in supersonic gas flow

    Science.gov (United States)

    Isaulova, T. N.; Lavit, I. M.

    2011-07-01

    This paper considers the vibrations of a skew inhomogeneous plate in gas flow. The plate is clamped in a certain section of one of its sides. Interaction of the flow with the plate is described using piston theory. The problem solution is based on the Hamilton's variational principle and finite element method. The calculation results are compared with known data of theoretical studies and experiments. For the inhomogeneous plate, similarity parameters were established for the problem, which, in practically important cases, appears to be self-similar for one of the similarity parameters. This allows one to reduce the solution of this problem to the solution of an algebraic eigenvalue problem.

  4. Measuring skew in average surface roughness as a function of surface preparation

    Science.gov (United States)

    Stahl, Mark T.

    2015-08-01

    Characterizing surface roughness is important for predicting optical performance. Better measurement of surface roughness reduces polishing time, saves money and allows the science requirements to be better defined. This study characterized statistics of average surface roughness as a function of polishing time. Average surface roughness was measured at 81 locations using a Zygo® white light interferometer at regular intervals during the polishing process. Each data set was fit to a normal and Largest Extreme Value (LEV) distribution; then tested for goodness of fit. We show that the skew in the average data changes as a function of polishing time.

  5. Does Realized Skewness Predict the Cross-Section of Equity Returns?

    DEFF Research Database (Denmark)

    Amaya, Diego; Christoffersen, Peter; Jacobs, Kris

    -statistic of 3.65. Our results on realized skewness are robust across a wide variety of implementations, sample periods, portfolio weightings, and firm characteristics, and are not captured by the Fama-French and Carhart factors. We find some evidence that the relationship between realized kurtosis and next week......’'s stock returns is positive, but the evidence is not always robust and statistically significant. We do not find a strong relationship between realized volatility and next week’'s stock returns....

  6. Extrinsic spin Hall effect induced by resonant skew scattering in graphene.

    Science.gov (United States)

    Ferreira, Aires; Rappoport, Tatiana G; Cazalilla, Miguel A; Castro Neto, A H

    2014-02-14

    We show that the extrinsic spin Hall effect can be engineered in monolayer graphene by decoration with small doses of adatoms, molecules, or nanoparticles originating local spin-orbit perturbations. The analysis of the single impurity scattering problem shows that intrinsic and Rashba spin-orbit local couplings enhance the spin Hall effect via skew scattering of charge carriers in the resonant regime. The solution of the transport equations for a random ensemble of spin-orbit impurities reveals that giant spin Hall currents are within the reach of the current state of the art in device fabrication. The spin Hall effect is robust with respect to thermal fluctuations and disorder averaging.

  7. A Simulation-Based Study on Bayesian Estimators for the Skew Brownian Motion

    Directory of Open Access Journals (Sweden)

    Manuel Barahona

    2016-06-01

    Full Text Available In analyzing a temporal data set from a continuous variable, diffusion processes can be suitable under certain conditions, depending on the distribution of increments. We are interested in processes where a semi-permeable barrier splits the state space, producing a skewed diffusion that can have different rates on each side. In this work, the asymptotic behavior of some Bayesian inferences for this class of processes is discussed and validated through simulations. As an application, we model the location of South American sea lions (Otaria flavescens on the coast of Calbuco, southern Chile, which can be used to understand how the foraging behavior of apex predators varies temporally and spatially.

  8. Information

    CERN Document Server

    Ritchie, L David

    1991-01-01

    This volume thoroughly covers the sub-field of information, and is one of the first in a series which synthesizes the research literature on major concepts in the field of communication. Each concise volume includes a research definition (concept explication) and presents a state-of-the-art analysis of theory and empirical findings related to the concept. After defining the word `information', the author contrasts non-linear and reflexive ideas about human communication with linear perspectives. Information is equated with uncertainty. The result presents a pattern for the process of conceptua

  9. Family Adjustment to Aphasia

    Science.gov (United States)

    ... Public / Speech, Language and Swallowing / Disorders and Diseases Family Adjustment to Aphasia Richard S. was a senior manager ... It also presents a great challenge to the family. There may be tension among family members and ...

  10. 75 FR 59683 - Trade Adjustment Assistance for Farmers

    Science.gov (United States)

    2010-09-28

    ... Foreign Agricultural Service Trade Adjustment Assistance for Farmers AGENCY: Foreign Agricultural Service... for Farmers Program Review Committee, comprised of representatives from USDA's Office of the Chief... assistance in FY 2011. FOR FURTHER INFORMATION, CONTACT: Trade Adjustment Assistance for Farmers...

  11. Remotely Adjustable Hydraulic Pump

    Science.gov (United States)

    Kouns, H. H.; Gardner, L. D.

    1987-01-01

    Outlet pressure adjusted to match varying loads. Electrohydraulic servo has positioned sleeve in leftmost position, adjusting outlet pressure to maximum value. Sleeve in equilibrium position, with control land covering control port. For lowest pressure setting, sleeve shifted toward right by increased pressure on sleeve shoulder from servovalve. Pump used in aircraft and robots, where hydraulic actuators repeatedly turned on and off, changing pump load frequently and over wide range.

  12. Robust bivariate error detection in skewed data with application to historical radiosonde winds

    KAUST Repository

    Sun, Ying

    2017-01-18

    The global historical radiosonde archives date back to the 1920s and contain the only directly observed measurements of temperature, wind, and moisture in the upper atmosphere, but they contain many random errors. Most of the focus on cleaning these large datasets has been on temperatures, but winds are important inputs to climate models and in studies of wind climatology. The bivariate distribution of the wind vector does not have elliptical contours but is skewed and heavy-tailed, so we develop two methods for outlier detection based on the bivariate skew-t (BST) distribution, using either distance-based or contour-based approaches to flag observations as potential outliers. We develop a framework to robustly estimate the parameters of the BST and then show how the tuning parameter to get these estimates is chosen. In simulation, we compare our methods with one based on a bivariate normal distribution and a nonparametric approach based on the bagplot. We then apply all four methods to the winds observed for over 35,000 radiosonde launches at a single station and demonstrate differences in the number of observations flagged across eight pressure levels and through time. In this pilot study, the method based on the BST contours performs very well.

  13. Stroh formalism in analysis of skew-symmetric and symmetric weight functions for interfacial cracks

    CERN Document Server

    Morini, Lorenzo; Movchan, Alexander; Movchan, Natalia

    2012-01-01

    The focus of the article is on analysis of skew-symmetric weight matrix functions for interfacial cracks in two dimensional anisotropic solids. It is shown that the Stroh formalism proves to be an efficient approach to this challenging task. Conventionally, the weight functions, both symmetric and skew-symmetric, can be identified as a non-trivial singular solutions of the homogeneous boundary value problem for a solid with a crack. For a semi-infinite crack, the problem can be reduced to solving a matrix Wiener-Hopf functional equation. Instead, the Stroh matrix representation of displacements and tractions, combined with a Riemann-Hilbert formulation, is used to obtain an algebraic eigenvalue problem, that is solved in a closed form. The proposed general method is applied to the case of a quasi-static semi-infinite crack propagation between two dissimilar orthotropic media: explicit expressions for the weight matrix functions are evaluated and then used in the computation of complex stress intensity factor ...

  14. Hematopoietic lineage skewing and intestinal epithelia degeneration in aged mice with telomerase RNA component deletion.

    Science.gov (United States)

    Chen, Jichun; Bryant, Mark A; Dent, James J; Sun, Yu; Desierto, Marie J; Young, Neal S

    2015-12-01

    A deletion of a telomerase RNA component (Terc(-/-)) in C57BL/6 (B6) mice resulted in hematopoietic lineage skewing with increased neutrophils and CD11b(+) myeloid cells and decreased red blood cells and CD45R(+) B lymphocytes when animals reach ages older than 12 months. There was no decline in bone marrow (BM) c-Kit(+)Sca-1(+)Lin(-) (KSL) cells in old Terc(-/-) mice, and the lineage skewing phenomenon was not transferred when BM cells from old Terc(-/-) donors were transplanted into young B6 recipients. Necropsy and histological examinations found minimal to no change in the lung, spleen and liver but detected severe epithelia degeneration, ulceration and infection in small and large intestines, leading to enteritis, typhlitis and colitis in old Terc(-/-) mice. In a mouse model of dextran-sulfate-sodium-induced typhlitis and colitis, development of intestinal pathology was associated with increases in neutrophils and CD11b(+) myeloid cells and a decrease in CD45R(+) B cells, similar to those observed in old Terc(-/-) mice. Treatment of 11-13 month old Terc(-/-) mice with antibiotic trimethoprim-sulfa water reduced neutrophils and myeloid cells and increased B lymphocytes in the blood, indicating that mitigation of intestinal infection and inflammation could alleviate hematological abnormalities in old Terc(-/-) animals.

  15. Maximum Parsimony and the Skewness Test: A Simulation Study of the Limits of Applicability

    Science.gov (United States)

    Määttä, Jussi; Roos, Teemu

    2016-01-01

    The maximum parsimony (MP) method for inferring phylogenies is widely used, but little is known about its limitations in non-asymptotic situations. This study employs large-scale computations with simulated phylogenetic data to estimate the probability that MP succeeds in finding the true phylogeny for up to twelve taxa and 256 characters. The set of candidate phylogenies are taken to be unrooted binary trees; for each simulated data set, the tree lengths of all (2n − 5)!! candidates are computed to evaluate quantities related to the performance of MP, such as the probability of finding the true phylogeny, the probability that the tree with the shortest length is unique, the probability that the true phylogeny has the shortest tree length, and the expected inverse of the number of trees sharing the shortest length. The tree length distributions are also used to evaluate and extend the skewness test of Hillis for distinguishing between random and phylogenetic data. The results indicate, for example, that the critical point after which MP achieves a success probability of at least 0.9 is roughly around 128 characters. The skewness test is found to perform well on simulated data and the study extends its scope to up to twelve taxa. PMID:27035667

  16. Velocity derivative skewness in isotropic turbulence and its measurement with hot wires

    Energy Technology Data Exchange (ETDEWEB)

    Burattini, Paolo [Universite Libre de Bruxelles, Physique Statistique et des Plasmas, Brussels (Belgium); University of Newcastle, Discipline of Mechanical Engineering, Newcastle, NSW (Australia); Lavoie, Philippe [Imperial College London, Department of Aeronautics, London (United Kingdom); Antonia, Robert A. [University of Newcastle, Discipline of Mechanical Engineering, Newcastle, NSW (Australia)

    2008-09-15

    We investigate the effect of the hot wire resolution on the measurement of the velocity derivative skewness in homogeneous isotropic turbulence. Single- and cross-wire configurations (with different lengths and separations of the wires, and temporal sampling resolution) are considered. Predictions of the attenuation on the basis of a model for the energy spectrum are compared to experimental and numerical data in grid and box turbulence, respectively. It is shown that the model-based correction is accurate for the single wire but not for the cross-wire. In the latter case, the effect of the separation between the wires is opposite to that found in the experiments and simulations. Moreover, the attenuation predicted by the numerical data is in good agreement with that observed in the experiment. For both probe configurations, the sampling resolution has a sizeable attenuation effect, but, for the X-probe, the impact of the separation between the wires is more important. In both cases, the length of the wires has only a minor effect, in the non-dimensional range of wire length investigated. Finally, the present experimental data support the conclusion that the skewness is constant with the Reynolds number, in agreement with Kolmogorov's 41 theory. (orig.)

  17. Skew Young diagram method in spectral decomposition of integrable lattice models

    CERN Document Server

    Kirillov, A N; Nakanishi, T; Kirillov, Anatol N.; Kuniba, Atsuo; Nakanishi, Tomoki

    1997-01-01

    The spectral decomposition of the path space of the vertex model associated to the vector representation of the quantized affine algebra $U_q(\\widehat{sl}_n)$ is studied. We give a one-to-one correspondence between the spin configurations and the semi-standard tableaux of skew Young diagrams. As a result we obtain a formula of the characters for the degeneracy of the spectrum in terms of skew Schur functions. We conjecture that our result describes the $sl_n$-module contents of the Yangian $Y(sl_n)$-module structures of the level 1 integrable modules of the affine Lie algebra $\\widehat{sl}_n$. An analogous result is obtained also for a vertex model associated to the quantized twisted affine algebra $U_q(A^{(2)}_{2n})$, where $Y(B_n)$ characters appear for the degeneracy of the spectrum. The relation to the spectrum of the Haldane-Shastry and the Polychronakos models are also discussed.

  18. Experimental and modeling study of the flow over a skewed bump

    Science.gov (United States)

    Ching, David S.; Elkins, Christopher J.; Eaton, John K.

    2016-11-01

    Three-dimensional separated flows can be very sensitive to geometry and inlet conditions, such that a small change in the geometry or the upstream boundary layer could cause the flow structure to change drastically. This study examines the geometric sensitivity of a skewed bump with axis ratio 4/3 by changing the angle of the bump with respect to the flow. The three-dimensional, three-component mean velocity field was acquired using Magnetic Resonance Velocimetry (MRV) for several bump angles. The flow is dominated by large coherent vortices in the wake. For a symmetric case, two counter-rotating vortices exist in the wake, but when the bump is skewed relative to the oncoming flow one vortex structure is much stronger and overwhelms the other vortex. A comparison to RANS simulations found that the RANS simulations predict the velocity fields with reasonable accuracy within the separation bubble, but are very inaccurate downstream of reattachment. Using a time-resolved MRV sequence, the shedding frequency of the wake was determined for two bump angles. Hot-wire anemometry confirmed the shedding frequencies found from the MRV data and observed that the shedding frequency is sensitive to the bump angle at low bump angles, but is insensitive at high bump angles. Funding provided by the Office of Naval Research.

  19. Theoretical And Experimental Analysis Of Aluminium Bars Rolling Process In Three-High Skew Rolling Mill

    Directory of Open Access Journals (Sweden)

    Stefanik A.

    2015-06-01

    Full Text Available Technology of round bars rolling on a three-high skew rolling mills allows rolling of standard materials such as steel and aluminum, as well as new materials, especially hard deformable materials. The paper presents the results of theoretical and experimental rolling process of aluminum bars with a diameter of 20 mm. As the stock round bars with a diameter of 25 mm made of aluminum grade 1050A and aluminum alloy grade 2017A were used. The rolling process of aluminum bars has been carried out in a single pass. The numerical analysis was carried out by using computer program Forge2011®. On the basis of theoretical research it has been determined the state of deformation, stress and temperature distribution during rolling of aluminum bars. In addition, the results of theoretical research allowed to determine the schema of the metal plastic flow in the roll gap. Verification of the theoretical research was carried out during the rolling of aluminum bars on the RSP 40/14 laboratory three-high skew rolling mill. From the finished bars were taken the samples to set the shape and compared with the results of theoretical research. Finished aluminum round bars were characterized by low ovality and good surface quality.

  20. Skew Scattering from Correlated Systems: Impurities and Collective Excitations in the Spin Hall Effect

    Science.gov (United States)

    Ziman, Timothy; Gu, Bo; Maekawa, Sadamichi

    2017-01-01

    The spin Hall effect is affected by the Coulomb interaction as well as spin-spin correlations in metals. Here we examine the enhancement in the effect caused by resonant skew scattering induced by electron correlations. For single-impurity scattering, local Coulomb correlations may significantly change the observed spin Hall angle. There may be additional effects because of the special atomic environment close to a surface — extra degeneracies compared to the bulk, enhanced correlations that move the relative d- or f-levels, and interference effects coming from the lower local dimension. Our results may explain the very large spin Hall angle observed in CuBi alloys. We discuss the impact on the spin Hall effect from cooperative effects, firstly in an itinerant ferromagnet where there is an anomaly near the Curie temperature originating from high-order spin fluctuations. The second case considered is a metallic spin glass, where exchange via slowly fluctuating magnetic moments may lead to the precession of an injected spin current. This decreases the net spin-charge conversion from skew scattering at temperatures below a value three or four times the freezing temperature.

  1. Different male versus female breeding periodicity helps mitigate offspring sex ratio skews in sea turtles

    Directory of Open Access Journals (Sweden)

    Graeme Clive Hays

    2014-09-01

    Full Text Available The implications of climate change for global biodiversity may be profound with those species with little capacity for adaptation being thought to be particularly vulnerable to warming. A classic case of groups for concern are those animals exhibiting temperature-dependent sex-determination (TSD, such as sea turtles, where climate warming may produce single sex populations and hence extinction. We show that, globally, female biased hatchling sex ratios dominate sea turtle populations (exceeding 3:1 in >50% records, which, at-a-glance, reiterates concerns for extinction. However, we also demonstrate that more frequent breeding by males, empirically shown by satellite tracking 23 individuals and supported by a generalized bio-energetic life history model, generates more balanced operational sex ratios (OSRs. Hence, concerns of increasingly skewed hatchling sex ratios and reduced population viability are less acute than previously thought for sea turtles. In fact, in some scenarios skewed hatchling sex ratios in groups with TSD may be adaptive to ensure optimum OSRs.

  2. Buffeting response of long-span cable-supported bridges under skew winds. Part 2: case study

    Science.gov (United States)

    Xu, Y. L.; Zhu, L. D.

    2005-03-01

    The finite-element-based framework for buffeting analysis of long-span cable-supported bridges under skew winds has been presented in Part 1 of this paper. The framework is now applied to the Tsing Ma Suspension Bridge in Hong Kong as a case study. The wind velocities and bridge responses measured by the Wind and Structural Health Monitoring System (WASHMS) of the bridge during Typhoon Sam in 1999 are first analyzed to find the skew wind characteristics surrounding the bridge, the modal damping ratios and acceleration responses of the bridge. The buffeting responses of the bridge under skew winds during Typhoon Sam are then computed using the wind characteristics and modal damping ratios measured from the field and the aerodynamic coefficients and flutter derivatives of the bridge deck and tower measured from the wind tunnel under skew winds. The computed acceleration responses of the bridge deck and cable are finally compared with the responses measured from the field. The comparison is found to be satisfactory in general and the case study forms a good practical demonstration for the verification of the proposed method for buffeting analysis of long-span cable-supported bridges under skew winds.

  3. Skewed X inactivation and survival: a 13-year follow-up study of elderly twins and singletons

    DEFF Research Database (Denmark)

    Mengel-From, Jonas; Thinggaard, Mikael; Christiansen, Lene;

    2012-01-01

    . In populations of women past 55-60 years of age, an increased degree of skewing (DS) is found. Here the association between age-related skewing and mortality is analyzed in a 13-year follow-up study of 500 women from three cohorts (73-100 years of age at intake). Women with low DS had significantly higher...... mortality than the majority of women who had a more skewed DS (hazard ratio: 1.30; 95% CI: 1.04-1.64). The association between X inactivation and mortality was replicated in dizygotic twin pairs for which the co-twin with the lowest DS also had a statistically significant tendency to die first in the twin...

  4. GENERALIZED PRECONDITIONED HERMITIAN AND SKEW-HERMITIAN SPLITTING METHODS FOR NON-HERMITIAN POSITIVE-DEFINITE LINEAR SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    Junfeng Yin; Quanyu Dou

    2012-01-01

    In this paper,a generalized preconditioned Hermitian and skew-Hermitian splitting (GPHSS) iteration method for a non-Hermitian positive-definite matrix is studied,which covers standard Hermitian and skew-Hermitian splitting (HSS) iteration and also many existing variants.Theoretical analysis gives an upper bound for the spectral radius of the iteration matrix.From practical point of view,we have analyzed and implemented inexact generalized preconditioned Hermitian and skew-Hermitian splitting (IGPHSS) iteration,which employs Krylov subspace methods as its inner processes.Numerical experiments from three-dimensional convection-diffusion equation show that the GPHSS and IGPHSS iterations are efficient and competitive with standard HSS iteration and AHSS iteration.

  5. Modelling non-normal data: The relationship between the skew-normal factor model and the quadratic factor model.

    Science.gov (United States)

    Smits, Iris A M; Timmerman, Marieke E; Stegeman, Alwin

    2016-05-01

    Maximum likelihood estimation of the linear factor model for continuous items assumes normally distributed item scores. We consider deviations from normality by means of a skew-normally distributed factor model or a quadratic factor model. We show that the item distributions under a skew-normal factor are equivalent to those under a quadratic model up to third-order moments. The reverse only holds if the quadratic loadings are equal to each other and within certain bounds. We illustrate that observed data which follow any skew-normal factor model can be so well approximated with the quadratic factor model that the models are empirically indistinguishable, and that the reverse does not hold in general. The choice between the two models to account for deviations of normality is illustrated by an empirical example from clinical psychology. © 2015 The British Psychological Society.

  6. Development of a contour map showing generalized skew coefficients of annual peak discharges of rural, unregulated streams in New York, excluding Long Island

    Science.gov (United States)

    Lumia, Richard; Baevsky, Yvonne H.

    2000-01-01

    Flood-frequency relations that are developed by fitting the logarithms of annual peak discharges to a Pearson Type-III distribution are sensitive to skew coefficients. Estimates of population skew for a site are improved when computed from the weighted average of (1) the sample (station) skew, and (2) an unbiased, generalized skew estimate. A weighting technique based on the number of years of record at each of 226 sites was used to develop a contour map of unbiased, generalized skew coefficients for New York. An attempt was made to group (regionalize) the station skew coefficients into five hydrologically similar areas of New York, but the statewide version proved to be as accurate as the regionalized version and therefore was adopted as the final generalized skew-coefficient map for New York. An error analysis showed the statewide contour map to have lower MSE?s (mean square errors) than those computed from (1) the five regional skewcoefficient contour maps, (2) a previously used (1982) nationwide skew coefficient map, and (3) the weighted mean of skew coefficients for sites within each of five hydrologically uniform, but distinct areas of New York.

  7. 75 FR 4098 - Utility Allowance Adjustments

    Science.gov (United States)

    2010-01-26

    ... URBAN DEVELOPMENT Utility Allowance Adjustments AGENCY: Office of the Chief Information Officer, HUD... are required to advise the Secretary of the need for and request of a new utility allowance for... whether the information will have practical utility; (2) Evaluate the accuracy of the agency's estimate...

  8. Uniform and strict persistence in monotone skew-product semiflows with applications to non-autonomous Nicholson systems

    Science.gov (United States)

    Obaya, Rafael; Sanz, Ana M.

    2016-10-01

    We determine sufficient conditions for uniform and strict persistence in the case of skew-product semiflows generated by solutions of non-autonomous families of cooperative systems of ODEs or delay FDEs in terms of the principal spectrums of some associated linear skew-product semiflows which admit a continuous separation. Our conditions are also necessary in the linear case. We apply our results to a noncooperative almost periodic Nicholson system with a patch structure, whose persistence turns out to be equivalent to the persistence of the linearized system along the null solution.

  9. Adjustment to Cancer: Anxiety and Distress (PDQ®)—Health Professional Version

    Science.gov (United States)

    Expert-reviewed information summary about the difficult emotional responses many cancer patients experience. This summary focuses on normal adjustment issues, psychosocial distress, and adjustment disorders.

  10. Auto Adjusting Astronomical Telescope

    Directory of Open Access Journals (Sweden)

    Rohit R. Ghalsasi

    2014-04-01

    Full Text Available Astronomical telescope is powerful and basic tool for star or celestial observation. Here we proposed integrated system using Raspberry Pi for auto adjusting astronomical telescope. This integrated circuit helps to control stellar monitoring, stellar targeting, and tracking functions of telescope. Astro compass gives the direction of the celestial objects.

  11. Psychological Adjustment and Homosexuality.

    Science.gov (United States)

    Gonsiorek, John C.

    In this paper, the diverse literature bearing on the topic of homosexuality and psychological adjustment is critically reviewed and synthesized. The first chapter discusses the most crucial methodological issue in this area, the problem of sampling. The kinds of samples used to date are critically examined, and some suggestions for improved…

  12. Nonlinear free flexural vibrations of functionally graded rectangular and skew plates under thermal environments

    CERN Document Server

    Sundararajan, N; Ganapathi, M; 10.1016/j.finel.2005.06.001

    2011-01-01

    The nonlinear formulation developed based on von Karman's assumptions is employed to study the free vibration characteristics of functionally graded material (FGM) plates subjected to thermal environment. Temperature field is assumed to be a uniform distribution over the plate surface and varied in the thickness direction. The material is assumed to be temperature dependent and graded in the thickness direction according to the power-law distribution in terms of volume fractions of the constituents. The effective material properties are estimated from the volume fractions and the material properties of the constituents using Mori-Tanaka homogenization method. The nonlinear governing equations obtained using Lagrange's equations of motion are solved using finite element procedure coupled with the direct iteration technique. The variation of nonlinear frequency ratio with amplitude is highlighted considering various parameters such as gradient index, temperature, thickness and aspect ratios, and skew angle. For...

  13. Dynamics of a Skew Tent Map in the Nonlinear Frobenius-Perron Equation

    Science.gov (United States)

    Katsuragi, Daisuke

    Return maps of the mean field in globally coupled map lattices (GCML) with a large system size were compared with those at the limit in a large system size. We adopted a nonlinear Frobenius-Perron equation (NFPE) for the limit in the large system size, and used a skew tent map as a chaotic map to simplify calculations in the NFPE. The return maps of the mean field for direct numerical calculations in the GCML usually fluctuate from those for numerical calculations in the NFPE. However, at some coupling strengths, there are totally different return maps between the GCML and the NFPE. We show that this strongly depends on the initial conditions at some coupling strengths.

  14. Cylindrical vortex wake model: skewed cylinder, application to yawed or tilted rotors

    DEFF Research Database (Denmark)

    Branlard, Emmanuel Simon Pierre; Gaunaa, Mac

    2016-01-01

    in Blade Element Momentum method codes for yawed conditions. Here, all the components of the full vortex system are analyzed in view of extending Blade Element Momentum models. The main assumptions of the current study are a constant uniform circulation, an infinite number of blades, an un-expanding wake......A vortex system consisting of a bound vortex disk, a root vortex and a vortex cylinder is presented and applied for skewed wake situations. Both the longitudinal and tangential components of vorticity of the cylinder are considered. A subset of this system leads to a model, which is commonly used...... shape and a finite tip-speed ratio. The investigation remains within the context of inviscid potential flow theory. The model is derived for horizontal-axis rotors in general, but results are presented for wind-turbine applications. For each vortex element, the velocity components in all directions...

  15. Gluten-containing grains skew gluten assessment in oats due to sample grind non-homogeneity.

    Science.gov (United States)

    Fritz, Ronald D; Chen, Yumin; Contreras, Veronica

    2017-02-01

    Oats are easily contaminated with gluten-rich kernels of wheat, rye and barley. These contaminants are like gluten 'pills', shown here to skew gluten analysis results. Using R-Biopharm R5 ELISA, we quantified gluten in gluten-free oatmeal servings from an in-market survey. For samples with a 5-20ppm reading on a first test, replicate analyses provided results ranging 160ppm. This suggests sample grinding may inadequately disperse gluten to allow a single accurate gluten assessment. To ascertain this, and characterize the distribution of 0.25-g gluten test results for kernel contaminated oats, twelve 50g samples of pure oats, each spiked with a wheat kernel, showed that 0.25g test results followed log-normal-like distributions. With this, we estimate probabilities of mis-assessment for a 'single measure/sample' relative to the gluten content.

  16. A cylindrical shell with an axial crack under skew-symmetric loading.

    Science.gov (United States)

    Yuceoglu, U.; Erdogan, F.

    1973-01-01

    The skew-symmetric problem for a cylindrical shell containing an axial crack is considered. It is assumed that the material has a special orthotropy - namely, that the shear modulus may be evaluated from the measured Young's moduli and Poisson ratios and is not an independent material constant. The problem is solved within the confines of an eighth-order linearized shallow shell theory. As numerical examples, the torsion of an isotropic cylinder and that of a specially orthotropic cylinder (titanium) are considered. The membrane and bending components of the stress intensity factor are calculated and are given as functions of a dimensionless shell parameter. In the torsion problem for the axially cracked cylinder the bending effects appear to be much more significant than that found for the circumferentially cracked cylindrical shell. Also, as the shell parameter increases, unlike the results found in the pressurized shell, the bending stresses around crack ends do not change sign.

  17. Homoclinic snaking in plane Couette flow: bending, skewing, and finite-size effects

    CERN Document Server

    Gibson, John F

    2015-01-01

    Invariant solutions of shear flows have recently been extended from spatially periodic solutions in minimal flow units to spatially localized solutions on extended domains. One set of spanwise-localized solutions of plane Couette flow exhibits homoclinic snaking, a process by which steady-state solutions grow additional structure smoothly at their fronts when continued parametrically. Homoclinic snaking is well understood mathematically in the context of the one-dimensional Swift-Hohenberg equation. Consequently, the snaking solutions of plane Couette flow form a promising connection between the largely phenomenological study of laminar-turbulent patterns in viscous shear flows and the mathematically well-developed field of pattern-formation theory. In this paper we present a numerical study of the snaking solutions, generalizing beyond the fixed streamwise wavelength of previous studies. We find a number of new solution features, including bending, skewing, and finite-size effects. We show that the finite-si...

  18. Kerr Effect from Diffractive Skew Scattering in Chiral px±i py Superconductors

    Science.gov (United States)

    König, Elio J.; Levchenko, Alex

    2017-01-01

    We calculate the temperature dependent anomalous ac Hall conductance σH(Ω ,T ) for a two-dimensional chiral p -wave superconductor. This quantity determines the polar Kerr effect, as it was observed in Sr2RuO4 [J. Xia et al., Phys. Rev. Lett. 97, 167002 (2006)]. We concentrate on a single band model with an arbitrary isotropic dispersion relation subjected to rare, weak impurities treated in the Born approximation. As we explicitly show by detailed computation, previously omitted contributions to the extrinsic part of an anomalous Hall response, physically originating from diffractive skew scattering on quantum impurity complexes, appear to the leading order in the impurity concentration. By direct comparison with published results from the literature we demonstrate the relevance of our findings for the interpretation of the Kerr effect measurements in superconductors.

  19. Separation of variables in anisotropic models and non-skew-symmetric elliptic r-matrix

    Science.gov (United States)

    Skrypnyk, Taras

    2017-05-01

    We solve a problem of separation of variables for the classical integrable hamiltonian systems possessing Lax matrices satisfying linear Poisson brackets with the non-skew-symmetric, non-dynamical elliptic so(3)⊗ so(3)-valued classical r-matrix. Using the corresponding Lax matrices, we present a general form of the "separating functions" B( u) and A( u) that generate the coordinates and the momenta of separation for the associated models. We consider several examples and perform the separation of variables for the classical anisotropic Euler's top, Steklov-Lyapunov model of the motion of anisotropic rigid body in the liquid, two-spin generalized Gaudin model and "spin" generalization of Steklov-Lyapunov model.

  20. INTRINSIC FEATURES OF TURBULENT FLOW IN STRONGLY 3-D SKEW BLADE PASSAGE OF A FRANCIS TURBINE

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-xiang; WANG Wen-quan; GUO Yakun

    2007-01-01

    The turbulent flow, with the Reynolds number of 5.9 105, in the strongly 3-D skew blade passage of a true Francis hydro turbine was simulated by the Large Eddy Simulation (LES) approach to investigate the spatial and temporal distributions of the fully developed turbulence in the passage with strongly 3-D complex geometry. The simulations show that the strong three-dimensionality of the passage has a great amplification effect on the turbulence in the passage, and the distributions of the turbulence are diversely nonuniform, for instance, the rise of turbulent kinetic energy in the lower 1/3 region of the passage is more than 45%, whereas its rise in the upper 1/3 region is less than 1%. With the LES approach, the details of the flow structures at the near-wall surfaces of the blades could be obtained. Several turbulent spots were captured.

  1. Mixing of orthogonal and skew-orthogonal polynomials and its relation to Wilson RMT

    CERN Document Server

    Kieburg, Mario

    2012-01-01

    The unitary Wilson random matrix theory is an interpolation between the chiral Gaussian unitary ensemble and the Gaussian unitary ensemble. This new way of interpolation is also reflected in the orthogonal polynomials corresponding to such a random matrix ensemble. Although the chiral Gaussian unitary ensemble as well as the Gaussian unitary ensemble are associated to the Dyson index $\\beta=2$ the intermediate ensembles exhibit a mixing of orthogonal polynomials and skew-orthogonal polynomials. We consider the Hermitian as well as the non-Hermitian Wilson random matrix and derive the corresponding polynomials, their recursion relations, Christoffel-Darboux-like formulas, Rodrigues formulas and representations as random matrix averages in a unifying way. With help of these results we derive the unquenched $k$-point correlation function of the Hermitian and then non-Hermitian Wilson random matrix in terms of two flavour partition functions only. This representation is due to a Pfaffian factorization drastically...

  2. Skewed Marriage Markets and Sex Ratios of Finnish People in their Twenties

    Directory of Open Access Journals (Sweden)

    Lassi Lainiala

    2014-03-01

    Full Text Available This article studies variation in regional sex ratios in Finland and outlines potential implications of the skewed sex ratios for family formation patterns. Difficulties in finding a suitable partner are typically mentioned as one of the most important reasons for remaining childless, and we explore if this reason is apparent structurally at the regional macro level. We found significant variation in sex ratios in age-groups 18–30 at the regional and sub-regional levels. Of the whole 20–29-year old population in Finland, almost 50 percent live in sub-region areas with a male surplus. As expected, a higher proportion of men compared to women appears to increase fertility of women in younger age groups. Contrary to expectations, high male-female ratios were not related to higher proportion of women living with a partner

  3. On Calculating the Hougaard Measure of Skewness in a Nonlinear Regression Model with Two Parameters

    Directory of Open Access Journals (Sweden)

    S. A. EL-Shehawy

    2009-01-01

    Full Text Available Problem statement: This study presented an alternative computational algorithm for determining the values of the Hougaard measure of skewness as a nonlinearity measure in a Nonlinear Regression model (NLR-model with two parameters. Approach: These values indicated a degree of a nonlinear behavior in the estimator of the parameter in a NLR-model. Results: We applied the suggested algorithm on an example of a NLR-model in which there is a conditionally linear parameter. The algorithm is mainly based on many earlier studies in measures of nonlinearity. The algorithm was suited for implementation using computer algebra systems such as MAPLE, MATLAB and MATHEMATICA. Conclusion/Recommendations: The results with the corresponding output the same considering example will be compared with the results in some earlier studies.

  4. Skew-orthogonal Laguerre polynomials for chiral real asymmetric random matrices

    Energy Technology Data Exchange (ETDEWEB)

    Akemann, G; Phillips, M J [Department of Mathematical Sciences and BURSt Research Centre, Brunel University West London, Uxbridge UB8 3PH (United Kingdom); Kieburg, M, E-mail: gernot.akemann@brunel.ac.u [Fakultaet fuer Physik, Universitaet Duisburg-Essen, 47048 Duisburg (Germany)

    2010-09-17

    We apply the method of skew-orthogonal polynomials (SOP) in the complex plane to asymmetric random matrices with real elements, belonging to two different classes. Explicit integral representations valid for arbitrary weight functions are derived for the SOP and for their Cauchy transforms, given as the expectation values of traces and determinants or their inverses, respectively. Our proof uses the fact that the joint probability distribution function for all combinations of real eigenvalues and complex conjugate eigenvalue pairs can be written as a product. Examples for the SOP are given in terms of Laguerre polynomials for the chiral ensemble (also called the non-Hermitian real Wishart-Laguerre ensemble), both without and with the insertion of characteristic polynomials. Such characteristic polynomials play the role of mass terms in applications to complex Dirac spectra in field theory. In addition, for the elliptic real Ginibre ensemble, we recover the SOP of Forrester and Nagao in terms of Hermite polynomials.

  5. Separation of variables in anisotropic models and non-skew-symmetric elliptic r-matrix

    Science.gov (United States)

    Skrypnyk, Taras

    2016-11-01

    We solve a problem of separation of variables for the classical integrable hamiltonian systems possessing Lax matrices satisfying linear Poisson brackets with the non-skew-symmetric, non-dynamical elliptic so(3)⊗ so(3) -valued classical r-matrix. Using the corresponding Lax matrices, we present a general form of the "separating functions" B(u) and A(u) that generate the coordinates and the momenta of separation for the associated models. We consider several examples and perform the separation of variables for the classical anisotropic Euler's top, Steklov-Lyapunov model of the motion of anisotropic rigid body in the liquid, two-spin generalized Gaudin model and "spin" generalization of Steklov-Lyapunov model.

  6. A novel generalized normal distribution for human longevity and other negatively skewed data.

    Science.gov (United States)

    Robertson, Henry T; Allison, David B

    2012-01-01

    Negatively skewed data arise occasionally in statistical practice; perhaps the most familiar example is the distribution of human longevity. Although other generalizations of the normal distribution exist, we demonstrate a new alternative that apparently fits human longevity data better. We propose an alternative approach of a normal distribution whose scale parameter is conditioned on attained age. This approach is consistent with previous findings that longevity conditioned on survival to the modal age behaves like a normal distribution. We derive such a distribution and demonstrate its accuracy in modeling human longevity data from life tables. The new distribution is characterized by 1. An intuitively straightforward genesis; 2. Closed forms for the pdf, cdf, mode, quantile, and hazard functions; and 3. Accessibility to non-statisticians, based on its close relationship to the normal distribution.

  7. Skew-orthogonal Laguerre polynomials for chiral real asymmetric random matrices

    CERN Document Server

    Akemann, G; Phillips, M J

    2010-01-01

    We apply the method of skew-orthogonal polynomials (SOP) in the complex plane to asymmetric random matrices with real elements, belonging to two different classes. Explicit integral representations valid for arbitrary weight functions are derived for the SOP and for their Cauchy transforms, given as expectation values of traces and determinants or their inverses, respectively. Our proof uses the fact that the joint probability distribution function for all combinations of real eigenvalues and complex conjugate eigenvalue pairs can be written as a product. Examples for the SOP are given in terms of Laguerre polynomials for the chiral ensemble (also called the non-Hermitian real Wishart-Laguerre ensemble), both without and with the insertion of characteristic polynomials. Such characteristic polynomials play the role of mass terms in applications to complex Dirac spectra in field theory. In addition, for the elliptic real Ginibre ensemble we recover the SOP of Forrester and Nagao in terms of Hermite polynomials...

  8. A q-Analogue of the Centralizer Construction and Skew Representations of the Quantum Affine Algebra

    Directory of Open Access Journals (Sweden)

    Mark J. Hopkins

    2006-12-01

    Full Text Available We prove an analogue of the Sylvester theorem for the generator matrices of the quantum affine algebra ${ m U}_q(widehat{mathfrak{gl}}_n$. We then use it to give an explicit realization of the skew representations of the quantum affine algebra. This allows one to identify them in a simple way by calculating their highest weight, Drinfeld polynomials and the Gelfand-Tsetlin character (or $q$-character. We also apply the quantum Sylvester theorem to construct a$q$-analogue of the Olshanski algebra as a projective limit of certaincentralizers in ${ m U}_q(mathfrak{gl}_n$ and show that this limit algebra contains the $q$-Yangian as a subalgebra.

  9. Prediction of the moments in advection-diffusion lattice Boltzmann method. I. Truncation dispersion, skewness, and kurtosis

    Science.gov (United States)

    Ginzburg, Irina

    2017-01-01

    The effect of the heterogeneity in the soil structure or the nonuniformity of the velocity field on the modeled resident time distribution (RTD) and breakthrough curves is quantified by their moments. While the first moment provides the effective velocity, the second moment is related to the longitudinal dispersion coefficient (kT) in the developed Taylor regime; the third and fourth moments are characterized by their normalized values skewness (Sk) and kurtosis (Ku), respectively. The purpose of this investigation is to examine the role of the truncation corrections of the numerical scheme in kT, Sk, and Ku because of their interference with the second moment, in the form of the numerical dispersion, and in the higher-order moments, by their definition. Our symbolic procedure is based on the recently proposed extended method of moments (EMM). Originally, the EMM restores any-order physical moments of the RTD or averaged distributions assuming that the solute concentration obeys the advection-diffusion equation in multidimensional steady-state velocity field, in streamwise-periodic heterogeneous structure. In our work, the EMM is generalized to the fourth-order-accurate apparent mass-conservation equation in two- and three-dimensional duct flows. The method looks for the solution of the transport equation as the product of a long harmonic wave and a spatially periodic oscillating component; the moments of the given numerical scheme are derived from a chain of the steady-state fourth-order equations at a single cell. This mathematical technique is exemplified for the truncation terms of the two-relaxation-time lattice Boltzmann scheme, using plug and parabolic flow in straight channel and cylindrical capillary with the d2Q9 and d3Q15 discrete velocity sets as simple but illustrative examples. The derived symbolic dependencies can be readily extended for advection by another, Newtonian or non-Newtonian, flow profile in any-shape open-tabular conduits. It is

  10. A missing model in reproductive skew theory: the bordered tug-of-war.

    Science.gov (United States)

    Reeve, Hudson Kern; Shen, Sheng-Feng

    2006-05-30

    Models of reproductive skew can be classified into two groups: transactional models, in which group members yield shares of reproduction to each other in return for cooperation, and tug-of-war models, in which group members invest group resources in a tug-of-war over their respective reproductive shares. We synthesize these two models to yield a "bordered tug-of-war" model in which the internal tug-of-war is limited ("bordered") by the requirement that group members must achieve a certain amount of reproduction lest they pursue a noncooperative option leading to group breakup. Previous attempts to synthesize these two models did not allow for the fact that the tug-of-war will affect group output, which in turn feeds back on the reproductive payments required by group members to remain cooperative. The bordered tug-of-war model, which does not assume complete reproductive control by any individual and allows for conflict within groups, predicts that the degree of within-group selfishness will increase as the noncooperative options become less attractive, e.g., as ecological constraints on solitary breeding increase. When the noncooperative option involves fighting for the group resource (e.g., territory) and leaving if the fight is lost, the subordinate's overall share of reproduction is predicted to be independent of its relatedness to the dominant and to increase the greater its probability of winning the fight, the less the value of the territory, and the greater its personal payoff for leaving. The unique predictions of the bordered tug-of-war model may fit skew data from a number of species, including meerkats, lions, and wood mice.

  11. Th1-skewed tissue responses to a mycolyl glycolipid in mycobacteria-infected rhesus macaques

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Daisuke; Miyamoto, Ayumi; Hattori, Yuki; Komori, Takaya [Laboratory of Cell Regulation, Institute for Virus Research, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507 (Japan); Nakamura, Takashi [Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12 Nishi 6, Kita-ku, Sapporo, Hokkaido 060-0812 (Japan); Igarashi, Tatsuhiko, E-mail: tigarash@virus.kyoto-u.ac.jp [Laboratory of Primate Model, Institute for Virus Research, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507 (Japan); Harashima, Hideyoshi, E-mail: harasima@pharm.hokudai.ac.jp [Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12 Nishi 6, Kita-ku, Sapporo, Hokkaido 060-0812 (Japan); Sugita, Masahiko, E-mail: msugita@virus.kyoto-u.ac.jp [Laboratory of Cell Regulation, Institute for Virus Research, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507 (Japan)

    2013-11-08

    Highlights: •Glucose monomycolate (GMM) is a marker glycolipid for active tuberculosis. •Tissue responses to GMM involved up-regulation of Th1-attracting chemokines. •Th1-skewed local responses were mounted at the GMM-injected tissue. -- Abstract: Trehalose 6,6′-dimycolate (TDM) is a major glycolipid of the cell wall of mycobacteria with remarkable adjuvant functions. To avoid detection by the host innate immune system, invading mycobacteria down-regulate the expression of TDM by utilizing host-derived glucose as a competitive substrate for their mycolyltransferases; however, this enzymatic reaction results in the concomitant biosynthesis of glucose monomycolate (GMM) which is recognized by the acquired immune system. GMM-specific, CD1-restricted T cell responses have been detected in the peripheral blood of infected human subjects and monkeys as well as in secondary lymphoid organs of small animals, such as guinea pigs and human CD1-transgenic mice. Nevertheless, it remains to be determined how tissues respond at the site where GMM is produced. Here we found that rhesus macaques vaccinated with Mycobacterium bovis bacillus Calmette–Guerin mounted a chemokine response in GMM-challenged skin that was favorable for recruiting T helper (Th)1 T cells. Indeed, the expression of interferon-γ, but not Th2 or Th17 cytokines, was prominent in the GMM-injected tissue. The GMM-elicited tissue response was also associated with the expression of monocyte/macrophage-attracting CC chemokines, such as CCL2, CCL4 and CCL8. Furthermore, the skin response to GMM involved the up-regulated expression of granulysin and perforin. Given that GMM is produced primarily by pathogenic mycobacteria proliferating within the host, the Th1-skewed tissue response to GMM may function efficiently at the site of infection.

  12. Information

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    There are unstructured abstracts (no more than 256 words) and structured abstracts (no more than 480). The specific requirements for structured abstracts are as follows:An informative, structured abstracts of no more than 4-80 words should accompany each manuscript. Abstracts for original contributions should be structured into the following sections. AIM (no more than 20 words): Only the purpose should be included. Please write the aim as the form of "To investigate/ study/..."; MATERIALS AND METHODS (no more than 140 words); RESULTS (no more than 294 words): You should present P values where appropnate and must provide relevant data to illustrate how they were obtained, e.g. 6.92 ± 3.86 vs 3.61 ± 1.67, P< 0.001; CONCLUSION (no more than 26 words).

  13. 75 FR 59685 - Trade Adjustment Assistance for Farmers

    Science.gov (United States)

    2010-09-28

    ... Foreign Agricultural Service Trade Adjustment Assistance for Farmers AGENCY: Foreign Agricultural Service... analyzed by USDA's Economic Research Service and reviewed by the Trade Adjustment Assistance for Farmers... assistance in FY 2011. FOR FURTHER INFORMATION CONTACT: Trade Adjustment Assistance for Farmers Program...

  14. Fiscal adjustment in Brazil

    Directory of Open Access Journals (Sweden)

    Fabiana Rocha

    2003-03-01

    Full Text Available Two questions are addressed in this paper. The first one is the determination of periods of fiscal consolidation and fiscal stimulus. The second one is the importance of the composition of fiscal adjustments for their success, defined as a declining debt to GDP ratio. We, characterize 1994 and 1999 as points of fiscal consolidation. The 1994 consolidation can not be considered successful since after that period the debt to GDP ratio has grown continuously. The adjustment can be characterized as a type 2 adjustment (Alesina and Perotti (1997 in the sense that cuts were made mainly in public investment, while government wages and transfers remained almost unchanged. This type of adjustment usually has a low likelihood of being a success.Duas questões são tratadas neste artigo. A primeira é a determinação dos períodos de consolidação fiscal e estímulo fiscal. A segunda questão é a importância da composição dos ajustamentos fiscais para o seu sucesso, definido como um declínio na razo dívida/PIB. Nós, caracterizamos 1994 e 1999 como pontos de consolidação fiscal. A consolidação de 1994 não pode ser considerada um sucesso pois nos anos seguintes a razão dívida/PIB cresceu continuamente. O ajustamento pode ser considerado como um ajustamento do tipo 2 (Alesina and Perotti, 1997 no sentido de que foram feitos cortes principalmente no investimento público, enquanto os salários e transferências permaneceram praticamente inalterados. Este tipo de ajustamento geralmente tem uma baixa probabilidade de sucesso.

  15. Development of the applicability of simplified Henry's method for skewed multicell box-girder bridges under traffic loading conditions

    Institute of Scientific and Technical Information of China (English)

    Iman MOHSENI; A.R.Khalim RASHID

    2012-01-01

    Concrete precast multicell box-girder (MCB) bridges combine aesthetics with torsional stiffness perfectly.Previous analytical studies indicate that currently available specifications are unable to consider the effect of the twisting moment (torsional moment) on bridge actions.In straight bridges the effect of torsion is negligible and the transverse reinforced design is governed by other requirements.However,in the case of skewed bridges the effect of the twisting moment should be considered.Therefore,an in-depth study was performed on 90 concrete MCB bridges with skew angles ranging from 0° to 60°.For each girder the bridge actions were determined under the American Association of State Highway and Transportation Officials (AASHTO) live load conditions.The analytical results show that torsional stiffness and live load positions greatly affected the bridges' responses.In addition,based on a statistical analysis of the obtained results,several skew correction factors are proposed to improve the precision of the simplified Henry's method,which is widely used by bridge engineers to predict bridge actions.The relationship between the bending moment and secondary moments was also investigated and it was concluded that all secondary actions increase with an increase in skewness.

  16. The role of semantics, pre-emption and skew in linguistic distributions: the case of the un-construction.

    Directory of Open Access Journals (Sweden)

    Paul eIbbotson

    2013-12-01

    Full Text Available We use the Google Ngram database, a corpus of 5,195,769 digitized books containing ~4% of all books ever published, to test three ideas that are hypothesized to account for linguistic generalizations: verbal semantics, pre-emption and skew. Using 828,813 tokens of un-forms as a test case for these mechanisms, we found verbal semantics was a good predictor of the frequency of un-forms in the English language over the past 200 years – both in terms of how the frequency changed over time and their rank frequency. We did not find strong evidence for the direct competition of un-forms and their top pre-emptors, however the skew of the un-construction competitors was inversely correlated with the acceptability of the un-form. We suggest a cognitive explanation for this, namely, that the more the set of relevant pre-emptors is skewed then the more easily it is retrieved from memory. This suggests that it is not just the frequency of pre-emptive forms that must be taken into account when trying to explain usage patterns but their skew as well.

  17. On the Empirical Importance of the Conditional Skewness Assumption in Modelling the Relationship between Risk and Return

    Science.gov (United States)

    Pipień, M.

    2008-09-01

    We present the results of an application of Bayesian inference in testing the relation between risk and return on the financial instruments. On the basis of the Intertemporal Capital Asset Pricing Model, proposed by Merton we built a general sampling distribution suitable in analysing this relationship. The most important feature of our assumptions is that the skewness of the conditional distribution of returns is used as an alternative source of relation between risk and return. This general specification relates to Skewed Generalized Autoregressive Conditionally Heteroscedastic-in-Mean model. In order to make conditional distribution of financial returns skewed we considered the unified approach based on the inverse probability integral transformation. In particular, we applied hidden truncation mechanism, inverse scale factors, order statistics concept, Beta and Bernstein distribution transformations and also a constructive method. Based on the daily excess returns on the Warsaw Stock Exchange Index we checked the empirical importance of the conditional skewness assumption on the relation between risk and return on the Warsaw Stock Market. We present posterior probabilities of all competing specifications as well as the posterior analysis of the positive sign of the tested relationship.

  18. A Note on the Skew Energy of Digraphs%有向图反能量的一个注记

    Institute of Scientific and Technical Information of China (English)

    崔淑玉; 田贵贤

    2013-01-01

    有向图的反能量是指有向图的反邻接矩阵的能量.本文利用有向图的运算构造出了几类有向图,它们中的每一个都满足有向图的反能量等于其底图的能量.部分回答了Adiga等人在文[The skew energy of a digraph,Linear Algebra Appl.,2010,432:1825 1835]中提出的一个公开问题.%The skew energy (&)s (D) of a digraph D is defined as the energy of its skewadjacency matrix.In this paper,employing many operations of digraphs,we construct several classes of digraphs,each one of which satisfies its skew energy is the same as the energy of its underlying graph.This work partly answers a problem proposed by Adiga et al.[The skew energy of a digraph,Linear Algebra Appl.,2010,432:1825-1835].

  19. Social Justice and South African University Student Enrolment Data by "Race", 1998-2012: From "Skewed Revolution" to "Stalled Revolution"

    Science.gov (United States)

    Cooper, David

    2015-01-01

    The paper looks closely at student enrolment trends through a case study of South African "race" enrolment data, including some hypotheses about how student social class has influenced these trends. First, data on 1988-1998 enrolments showing a "skewed revolution" in student africanisation are summarised. Then, using 2000-2012…

  20. Contribution of Co-Skewness and Co-Kurtosis of the Higher Moment CAPM for Finding the Technical Efficiency

    Directory of Open Access Journals (Sweden)

    Md. Zobaer Hasan

    2014-01-01

    Full Text Available The objective of this paper is to present the technical efficiency of individual companies and their respective groups of Bangladesh stock market (i.e., Dhaka Stock Exchange, DSE by using two risk factors (co-skewness and co-kurtosis as the additional input variables in the Stochastic Frontier Analysis (SFA. The co-skewness and co-kurtosis are derived from the Higher Moment Capital Asset Pricing Model (H-CAPM. To investigate the contribution of these two factors, two types of technical efficiency are derived: (1 technical efficiency with considering co-skewness and co-kurtosis (WSK and (2 technical efficiency without considering co-skewness and co-kurtosis (WOSK. By comparing these two types of technical efficiency, it is noticed that the technical efficiency of WSK is higher than the technical efficiency of WOSK for the individual companies and their respective groups. As per available literature in the context Bangladesh stock market, no study has been conducted thus far to measure technical efficiency of companies and their respective groups by using the risk factors which are derived from the H-CAPM. In this research, the link between H-CAPM and SFA is established for measuring technical efficiency and it is believed that the findings of this study may be applied to other emerging stock markets.

  1. Bayesian WLS/GLS regression for regional skewness analysis for regions with large crest stage gage networks

    Science.gov (United States)

    Veilleux, Andrea G.; Stedinger, Jery R.; Eash, David A.

    2012-01-01

    This paper summarizes methodological advances in regional log-space skewness analyses that support flood-frequency analysis with the log Pearson Type III (LP3) distribution. A Bayesian Weighted Least Squares/Generalized Least Squares (B-WLS/B-GLS) methodology that relates observed skewness coefficient estimators to basin characteristics in conjunction with diagnostic statistics represents an extension of the previously developed B-GLS methodology. B-WLS/B-GLS has been shown to be effective in two California studies. B-WLS/B-GLS uses B-WLS to generate stable estimators of model parameters and B-GLS to estimate the precision of those B-WLS regression parameters, as well as the precision of the model. The study described here employs this methodology to develop a regional skewness model for the State of Iowa. To provide cost effective peak-flow data for smaller drainage basins in Iowa, the U.S. Geological Survey operates a large network of crest stage gages (CSGs) that only record flow values above an identified recording threshold (thus producing a censored data record). CSGs are different from continuous-record gages, which record almost all flow values and have been used in previous B-GLS and B-WLS/B-GLS regional skewness studies. The complexity of analyzing a large CSG network is addressed by using the B-WLS/B-GLS framework along with the Expected Moments Algorithm (EMA). Because EMA allows for the censoring of low outliers, as well as the use of estimated interval discharges for missing, censored, and historic data, it complicates the calculations of effective record length (and effective concurrent record length) used to describe the precision of sample estimators because the peak discharges are no longer solely represented by single values. Thus new record length calculations were developed. The regional skewness analysis for the State of Iowa illustrates the value of the new B-WLS/BGLS methodology with these new extensions.

  2. Chemical Thermodynamics and Information Theory with Applications

    CERN Document Server

    Graham, Daniel J

    2011-01-01

    Thermodynamics and information touch theory every facet of chemistry. However, the physical chemistry curriculum digested by students worldwide is still heavily skewed toward heat/work principles established more than a century ago. Rectifying this situation, Chemical Thermodynamics and Information Theory with Applications explores applications drawn from the intersection of thermodynamics and information theory--two mature and far-reaching fields. In an approach that intertwines information science and chemistry, this book covers: The informational aspects of thermodynamic state equations The

  3. NPIP: A skew line needle configuration optimization system for HDR brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Siauw, Timmy; Cunha, Adam; Berenson, Dmitry; Atamtuerk, Alper; Hsu, I-Chow; Goldberg, Ken; Pouliot, Jean [Department of Civil and Environmental Engineering, University of California, Berkeley, 760 Davis Hall, Berkeley, California 94720-1710 (United States); Department of Radiation Oncology, University of California, San Francisco, Comprehensive Cancer Center, 1600 Divisadero Street, Suite H1031, San Francisco, California 94143-1708 (United States); Department of Electrical Engineering and Computer Science, University of California, Berkeley, 4th Floor Sutardja Dai Hall, Berkeley, California 94720-1764 (United States); Department of Industrial Engineering and Operations, University of California, Berkeley, 4141 Etcheverry Hall, Berkeley, California 94720-1777 (United States); Department of Radiation Oncology, University of California, San Francisco, Comprehensive Cancer Center, 1600 Divisadero Street, Suite H1031, San Francisco, California 94143-1708 (United States); Department of Industrial Engineering and Operations Research and Department of Electrical Engineering and Computer Science, University of California, Berkeley, 4141 Etcheverry Hall, Berkeley, California 94720-1777 (United States); Department of Radiation Oncology, University of California, San Francisco, Comprehensive Cancer Center, 1600 Divisadero Street, Suite H1031, San Francisco, California 94143-1708 (United States)

    2012-07-15

    Purpose: In this study, the authors introduce skew line needle configurations for high dose rate (HDR) brachytherapy and needle planning by integer program (NPIP), a computational method for generating these configurations. NPIP generates needle configurations that are specific to the anatomy of the patient, avoid critical structures near the penile bulb and other healthy structures, and avoid needle collisions inside the body. Methods: NPIP consisted of three major components: a method for generating a set of candidate needles, a needle selection component that chose a candidate needle subset to be inserted, and a dose planner for verifying that the final needle configuration could meet dose objectives. NPIP was used to compute needle configurations for prostate cancer data sets from patients previously treated at our clinic. NPIP took two user-parameters: a number of candidate needles, and needle coverage radius, {delta}. The candidate needle set consisted of 5000 needles, and a range of {delta} values was used to compute different needle configurations for each patient. Dose plans were computed for each needle configuration. The number of needles generated and dosimetry were analyzed and compared to the physician implant. Results: NPIP computed at least one needle configuration for every patient that met dose objectives, avoided healthy structures and needle collisions, and used as many or fewer needles than standard practice. These needle configurations corresponded to a narrow range of {delta} values, which could be used as default values if this system is used in practice. The average end-to-end runtime for this implementation of NPIP was 286 s, but there was a wide variation from case to case. Conclusions: The authors have shown that NPIP can automatically generate skew line needle configurations with the aforementioned properties, and that given the correct input parameters, NPIP can generate needle configurations which meet dose objectives and use as many

  4. Skew scattering dominated anomalous Hall effect in Cox(MgO)100-x granular thin films

    KAUST Repository

    Zhang, Qiang

    2017-07-31

    We investigated the mechanism(s) of the anomalous Hall effect (AHE) in magnetic granular materials by fabricating 100-nm-thick thin films of Cox(MgO)100-x with a Co volume fraction of 34≤x≤100 using co-sputtering at room temperature. We measured the temperature dependence of longitudinal resistivity (ρxx) and anomalous Hall resistivity (ρAHE) from 5 K to 300 K in all samples. We found that when x decreases from 100 to 34, the values of ρxx and ρAHE respectively increased by about four and three orders in magnitude. By linearly fitting the data, obtained at 5 K, of anomalous Hall coefficient (Rs) and of ρxx to log(Rs)~γlog(ρxx), we found that our results perfectly fell on a straight line with a slope of γ= 0.97±0.02. This fitting value of γ in Rsρxxγ clearly suggests that skew scattering dominated the AHE in this granular system. To explore the effect of the scattering on the AHE, we performed the same measurements on annealed samples. We found that although both ρxx and ρAHE significantly reduced after annealing, the correlation between them was almost the same, which was confirmed by the fitted value, γ=0.99±0.03. These data strongly suggest that the AHE originates from the skew scattering in Co-MgO granular thin films no matter how strong the scatterings of electrons by the interfaces and defects is. This observation may be of importance to the development of spintronic devices based on MgO.

  5. Adjustment Criterion and Algorithm in Adjustment Model with Uncertain

    Directory of Open Access Journals (Sweden)

    SONG Yingchun

    2015-02-01

    Full Text Available Uncertainty often exists in the process of obtaining measurement data, which affects the reliability of parameter estimation. This paper establishes a new adjustment model in which uncertainty is incorporated into the function model as a parameter. A new adjustment criterion and its iterative algorithm are given based on uncertainty propagation law in the residual error, in which the maximum possible uncertainty is minimized. This paper also analyzes, with examples, the different adjustment criteria and features of optimal solutions about the least-squares adjustment, the uncertainty adjustment and total least-squares adjustment. Existing error theory is extended with new observational data processing method about uncertainty.

  6. Sustainable urban regime adjustments

    DEFF Research Database (Denmark)

    Quitzau, Maj-Britt; Jensen, Jens Stissing; Elle, Morten

    2013-01-01

    The endogenous agency that urban governments increasingly portray by making conscious and planned efforts to adjust the regimes they operate within is currently not well captured in transition studies. There is a need to acknowledge the ambiguity of regime enactment at the urban scale. This directs...... attention to the transformative implications of conscious strategic maneuvering by incumbent regime actors, when confronting regime structurations. This article provides insight to processes of regime enactment performed by local governments by applying a flow-oriented perspective on regime dynamics...

  7. Adjustable Reeds For Weaving

    Science.gov (United States)

    Farley, Gary L.

    1994-01-01

    Local characteristics of fabrics varied to suit special applications. Adjustable reed machinery proposed for use in weaving fabrics in various net shapes, widths, yarn spacings, and yarn angles. Locations of edges of fabric and configuration of warp and filling yarns varied along fabric to obtain specified properties. In machinery, reed wires mounted in groups on sliders, mounted on lengthwise rails in reed frame. Mechanisms incorporated to move sliders lengthwise, parallel to warp yarns, by sliding them along rails; move sliders crosswise by translating reed frame rails perpendicular to warp yarns; and crosswise by spreading reed rails within group. Profile of reed wires in group on each slider changed.

  8. Jordan Adjusted Human Development

    OpenAIRE

    Ababsa, Myriam

    2014-01-01

    Jordan Human Development Index (HDI) and Adjusted Human Development Index (IHDI) In 1990, the United Nations Development Programme designed a Human Development Index composed of life expectancy at birth, level of education and gross domestic product (GDP) per capita. In 2011, the UNDP ranked Jordan 95th out of 187 countries with a human development index of 0.698, up from 0.591 in 1990, making it the leading medium-range country for human development (fig. VIII.1). In 2010, the inequality adj...

  9. Adjusting to the Emergent

    DEFF Research Database (Denmark)

    Revsbæk, Line

    of ‘adjusting to the emergent’. Newcomer innovation is portrayed as carrying a variety of possible significations, such as unintentional innovation effects of newcomer’s proactive self-socializing behavior; an inspirational basis for designing innovation-generating employee induction; ‘resonant instances...... in standardized induction programs where newcomers are cast in roles as insecure novices needing to be “taught the ropes” of the organizational culture. Linked with this, it is suggested that the prevailing dichotomy of ‘newcomer assimilation’ versus ‘organizational accommodation’ is replaced with a notion...

  10. Continuously adjustable Pulfrich spectacles

    Science.gov (United States)

    Jacobs, Ken; Karpf, Ron

    2011-03-01

    A number of Pulfrich 3-D movies and TV shows have been produced, but the standard implementation has inherent drawbacks. The movie and TV industries have correctly concluded that the standard Pulfrich 3-D implementation is not a useful 3-D technique. Continuously Adjustable Pulfrich Spectacles (CAPS) is a new implementation of the Pulfrich effect that allows any scene containing movement in a standard 2-D movie, which are most scenes, to be optionally viewed in 3-D using inexpensive viewing specs. Recent scientific results in the fields of human perception, optoelectronics, video compression and video format conversion are translated into a new implementation of Pulfrich 3- D. CAPS uses these results to continuously adjust to the movie so that the viewing spectacles always conform to the optical density that optimizes the Pulfrich stereoscopic illusion. CAPS instantly provides 3-D immersion to any moving scene in any 2-D movie. Without the glasses, the movie will appear as a normal 2-D image. CAPS work on any viewing device, and with any distribution medium. CAPS is appropriate for viewing Internet streamed movies in 3-D.

  11. Allele-Skewed DNA Modification in the Brain: Relevance to a Schizophrenia GWAS.

    Science.gov (United States)

    Gagliano, Sarah A; Ptak, Carolyn; Mak, Denise Y F; Shamsi, Mehrdad; Oh, Gabriel; Knight, Joanne; Boutros, Paul C; Petronis, Arturas

    2016-05-05

    Numerous recent studies have suggested that phenotypic effects of DNA sequence variants can be mediated or modulated by their epigenetic marks, such as allele-skewed DNA modification (ASM). Using Affymetrix SNP microarrays, we performed a comprehensive search of ASM effects in human post-mortem brain and sperm samples (total n = 256) from individuals with major psychosis and control individuals. Depending on the phenotypic category of the brain samples, 1.4%-7.5% of interrogated SNPs exhibited ASM effects. Next, we investigated ASM in the context of genetic studies of schizophrenia and detected that brain ASM SNPs were significantly overrepresented among sub-threshold SNPs from a schizophrenia genome-wide association study (GWAS). Brain ASM SNPs showed a much stronger enrichment in a schizophrenia GWAS than in 17 large GWASs of non-psychiatric diseases and traits, arguing that ASM effects are at least partially tissue specific. Studies of germline and control brain ASM SNPs supported a causal association between ASM and schizophrenia. Finally, significantly higher proportions of ASM SNPs than of non-ASM SNPs were detected at loci exhibiting epigenetic signatures of enhancers and promoters, and they were overrepresented within transcription factor binding regions and DNase I hypersensitive sites. All of these findings collectively indicate that ASM SNPs should be prioritized in follow-up GWASs.

  12. Effect of ellipse orientation on the thermoelastic behaviour of skew laminated composite plate with elliptical cutout

    Indian Academy of Sciences (India)

    M S R Niranjan Kumar; M M M Sarcar; V Bala Krishna Murthy; K M Rao

    2009-02-01

    An effort is made to study the thermoelastic behaviour of a cross-ply laminated composite skew plate with elliptical cutout subjected to pressure and non-linearly varying temperature loading in the present analysis. Orientation of the elliptical cut out is varied from 0° to 180° with respect to horizontal at an interval of 30° in the anti clockwise direction is considered for the present analysis. A three-dimensional heat conduction analysis in fibre reinforced composite laminates has been simulated by finite element method to get realistic temperature in the laminate under different thermal boundary conditions. A finite element method, which works on the basis of three-dimensional theory of elasticity, is employed to evaluate the stresses and deformations. The effect of orientation due to pressure loading on the stresses and transverse deflection is observed to be insignificant. The magnitudes of the in-plane normal stresses, x and y, for temperature loading are greatly affected by ellipse orientation and are observed to be minimum at the ellipse orientation of 0° and 90°, respectively. The in-plane and inter-laminar shear stresses are observed to be minimum at the ellipse orientation of 90°.

  13. Connection with Totally Skew-Symmetric Torsion on Riemannian Almost Product Manifolds

    CERN Document Server

    Mekerov, Dimitar

    2010-01-01

    On Riemannian almost product manifolds (M,P,g) with trP=0 we consider a linear connection nabla' preserving the almost product structure P and the metric g and having a totally skew-symmetric torsion tensor. We prove that if (M,P,g) admits such a connection then (M,P,g) belongs to the basic class W3 from the classification in [M.Staikova, K.Gribachev. Canonical connections and their conformal invariants on Riemannian P-manifolds, Serdica Math. J. 18 (1992), 150-161]. We consider the case when the curvature tensor of nabla' on (M,P,g) in W3 has the same properties like the ones of the curvature tensor of the Levi-Civita connection nabla on (M,P,g) with nabla(P)=0. We construct a 4-parametric family of 4-dimensional Riemannian manifolds of the class W3 by a Lie group and consider the connection nabla' on an arbitrary manifold of this family.

  14. A Timing Estimation Method Based-on Skewness Analysis in Vehicular Wireless Networks

    Directory of Open Access Journals (Sweden)

    Xuerong Cui

    2015-11-01

    Full Text Available Vehicle positioning technology has drawn more and more attention in vehicular wireless networks to reduce transportation time and traffic accidents. Nowadays, global navigation satellite systems (GNSS are widely used in land vehicle positioning, but most of them are lack precision and reliability in situations where their signals are blocked. Positioning systems base-on short range wireless communication are another effective way that can be used in vehicle positioning or vehicle ranging. IEEE 802.11p is a new real-time short range wireless communication standard for vehicles, so a new method is proposed to estimate the time delay or ranges between vehicles based on the IEEE 802.11p standard which includes three main steps: cross-correlation between the received signal and the short preamble, summing up the correlated results in groups, and finding the maximum peak using a dynamic threshold based on the skewness analysis. With the range between each vehicle or road-side infrastructure, the position of neighboring vehicles can be estimated correctly. Simulation results were presented in the International Telecommunications Union (ITU vehicular multipath channel, which show that the proposed method provides better precision than some well-known timing estimation techniques, especially in low signal to noise ratio (SNR environments.

  15. Viruses-to-mobile genetic elements skew in the deep Atlantis II brine pool sediments

    KAUST Repository

    Adel, Mustafa

    2016-09-06

    The central rift of the Red Sea has 25 brine pools with different physical and geochemical characteristics. Atlantis II (ATIID), Discovery Deeps (DD) and Chain Deep (CD) are characterized by high salinity, temperature and metal content. Several studies reported microbial communities in these brine pools, but few studies addressed the brine pool sediments. Therefore, sediment cores were collected from ATIID, DD, CD brine pools and an adjacent brine-influenced site. Sixteen different lithologic sediment sections were subjected to shotgun DNA pyrosequencing to generate 1.47 billion base pairs (1.47 × 109 bp). We generated sediment-specific reads and attempted to annotate all reads. We report the phylogenetic and biochemical uniqueness of the deepest ATIID sulfur-rich brine pool sediments. In contrary to all other sediment sections, bacteria dominate the deepest ATIID sulfur-rich brine pool sediments. This decrease in virus-to-bacteria ratio in selected sections and depth coincided with an overrepresentation of mobile genetic elements. Skewing in the composition of viruses-to-mobile genetic elements may uniquely contribute to the distinct microbial consortium in sediments in proximity to hydrothermally active vents of the Red Sea and possibly in their surroundings, through differential horizontal gene transfer.

  16. Discovery of Red-Skewed K_alpha iron line in Cyg X-2 with Suzaku

    CERN Document Server

    Shaposhnikov, Nikolai; Laurent, Philippe

    2009-01-01

    We report on the Suzaku observation of neutron star low-mass X-ray binary Cygnus X-2 which reveals a presence of the iron K_alpha emission line. The line profile shows a significant red wing. This discovery increases the number of neutron star sources where red-skewed iron lines were observed and strongly suggests that this phenomenon is common not only in black holes but also in other types of accreting compact objects. We examine the line profile in terms of models which attribute its production to the relativistic effects due to reflection of X-ray radiation from a cold accretion disk and also as a result of the line formation in the extended wind/outflow configuration. Both models are able to adequately represent the observed line profile. We consider the results of line modeling in the context of subsecond variability. While we were unable to conclusively disqualify one of the models, we find that the wind paradigm has several advantages over the relativistic disk reflection model.

  17. Inhibition of RORγT Skews TCRα Gene Rearrangement and Limits T Cell Repertoire Diversity

    Directory of Open Access Journals (Sweden)

    Yanxia Guo

    2016-12-01

    Full Text Available Recent studies have elucidated the molecular mechanism of RORγT transcriptional regulation of Th17 differentiation and function. RORγT was initially identified as a transcription factor required for thymopoiesis by maintaining survival of CD4+CD8+ (DP thymocytes. While RORγ antagonists are currently being developed to treat autoimmunity, it remains unclear how RORγT inhibition may impact thymocyte development. In this study, we show that in addition to regulating DP thymocytes survival, RORγT also controls genes that regulate thymocyte migration, proliferation, and T cell receptor (TCRα selection. Strikingly, pharmacological inhibition of RORγ skews TCRα gene rearrangement, limits T cell repertoire diversity, and inhibits development of autoimmune encephalomyelitis. Thus, targeting RORγT not only inhibits Th17 cell development and function but also fundamentally alters thymic-emigrant recognition of self and foreign antigens. The analysis of RORγ inhibitors has allowed us to gain a broader perspective of the diverse function of RORγT and its impact on T cell biology.

  18. A unique dermal dendritic cell subset that skews the immune response toward Th2.

    Directory of Open Access Journals (Sweden)

    Ryuichi Murakami

    Full Text Available Dendritic cell (DC subsets in the skin and draining lymph nodes (LNs are likely to elicit distinct immune response types. In skin and skin-draining LNs, a dermal DC subset expressing macrophage galactose-type C-type lectin 2 (MGL2/CD301b was found distinct from migratory Langerhans cells (LCs or CD103(+ dermal DCs (dDCs. Lower expression levels of Th1-promoting and/or cross-presentation-related molecules were suggested by the transcriptome analysis and verified by the quantitative real-time PCR analysis in MGL2(+ dDCs than in CD103(+ dDCs. Transfer of MGL2(+ dDCs but not CD103(+ dDCs from FITC-sensitized mice induced a Th2-type immune response in vivo in a model of contact hypersensitivity. Targeting MGL2(+ dDCs with a rat monoclonal antibody against MGL2 efficiently induced a humoral immune response with Th2-type properties, as determined by the antibody subclass. We propose that the properties of MGL2(+ dDCs, are complementary to those of CD103(+ dDCs and skew the immune response toward a Th2-type response.

  19. Robustness of S1 statistic with Hodges-Lehmann for skewed distributions

    Science.gov (United States)

    Ahad, Nor Aishah; Yahaya, Sharipah Soaad Syed; Yin, Lee Ping

    2016-10-01

    Analysis of variance (ANOVA) is a common use parametric method to test the differences in means for more than two groups when the populations are normally distributed. ANOVA is highly inefficient under the influence of non- normal and heteroscedastic settings. When the assumptions are violated, researchers are looking for alternative such as Kruskal-Wallis under nonparametric or robust method. This study focused on flexible method, S1 statistic for comparing groups using median as the location estimator. S1 statistic was modified by substituting the median with Hodges-Lehmann and the default scale estimator with the variance of Hodges-Lehmann and MADn to produce two different test statistics for comparing groups. Bootstrap method was used for testing the hypotheses since the sampling distributions of these modified S1 statistics are unknown. The performance of the proposed statistic in terms of Type I error was measured and compared against the original S1 statistic, ANOVA and Kruskal-Wallis. The propose procedures show improvement compared to the original statistic especially under extremely skewed distribution.

  20. The First Trimester Gravid Serum Regulates Procalcitonin Expression in Human Macrophages Skewing Their Phenotype In Vitro

    Directory of Open Access Journals (Sweden)

    Damiano Rami

    2014-01-01

    Full Text Available Procalcitonin (PCT is one of the best diagnostic and prognostic markers in clinical practice, widely used to evaluate the evolution of bacterial infections. Although it is mainly produced by thyroid, during sepsis almost all the peripheral tissues are involved in PCT production. Parenchymal cells have been suggested as the main source of PCT expression; however the contribution of macrophages is not clear yet. In response to environmental cues, tissue macrophages acquire distinct functional phenotypes, ranging from proinflammatory (M1 to anti-inflammatory (M2 phenotype. Macrophages at the fetal-maternal interface show immunosuppressive M2-like activities required for the maintenance of immunological homeostasis during pregnancy. This study aims to clarify the ability to synthesise PCT of fully differentiated (M0, polarized (M1/M2 macrophages and those cultured either in the presence of first trimester gravid serum (GS or pregnancy hormones. We found out that M1 macrophages upregulate PCT expression following LPS stimulation compared to M0 and M2. The GS downregulates PCT expression in macrophages, skewing them towards an M2-like phenotype. This effect seems only partially mediated by the hormonal milieu. Our findings strengthen the key role of macrophages in counteracting inflammatory stimuli during pregnancy, suggesting PCT as a possible new marker of M1-like macrophages.

  1. The first trimester gravid serum regulates procalcitonin expression in human macrophages skewing their phenotype in vitro.

    Science.gov (United States)

    Rami, Damiano; La Bianca, Martina; Agostinis, Chiara; Zauli, Giorgio; Radillo, Oriano; Bulla, Roberta

    2014-01-01

    Procalcitonin (PCT) is one of the best diagnostic and prognostic markers in clinical practice, widely used to evaluate the evolution of bacterial infections. Although it is mainly produced by thyroid, during sepsis almost all the peripheral tissues are involved in PCT production. Parenchymal cells have been suggested as the main source of PCT expression; however the contribution of macrophages is not clear yet. In response to environmental cues, tissue macrophages acquire distinct functional phenotypes, ranging from proinflammatory (M1) to anti-inflammatory (M2) phenotype. Macrophages at the fetal-maternal interface show immunosuppressive M2-like activities required for the maintenance of immunological homeostasis during pregnancy. This study aims to clarify the ability to synthesise PCT of fully differentiated (M0), polarized (M1/M2) macrophages and those cultured either in the presence of first trimester gravid serum (GS) or pregnancy hormones. We found out that M1 macrophages upregulate PCT expression following LPS stimulation compared to M0 and M2. The GS downregulates PCT expression in macrophages, skewing them towards an M2-like phenotype. This effect seems only partially mediated by the hormonal milieu. Our findings strengthen the key role of macrophages in counteracting inflammatory stimuli during pregnancy, suggesting PCT as a possible new marker of M1-like macrophages.

  2. Improvement of Moderately Loaded Transonic Axial Compressor Performance Using Low Porosity Bend Skewed Casing Treatment

    Directory of Open Access Journals (Sweden)

    Dilipkumar Bhanudasji Alone

    2014-01-01

    Full Text Available This paper presents experimental results of a single stage transonic axial flow compressor coupled with low porosity bend skewed casing treatment. The casing treatment has a plenum chamber above the bend slots. The depth of the plenum chamber is varied to understand its impact on the performance of compressor stage. The performance of the compressor stage is evaluated for casing treatment and plenum chamber configurations at two axial locations of 20% and 40%. Experimental results reveal that the stall margin of the compressor stage increases with increase in the plenum chamber volume. Hot-wire measurements show significant reduction in the turbulence intensity with increase in the plenum chamber volume compared to that with the solid casing at the stall condition. At higher operating speeds of 80% and at 20% axial coverage, the stall margin of the compressor increases by 20% with half and full plenum depth. The improvement in the peak stage efficiency observed is 4.6% with half plenum configuration and 3.34% with the full plenum configuration. The maximum improvement in the stall margin of 29.16% is obtained at 50% operating speed with full plenum configurations at 40% axial coverage.

  3. The male handicap: male-biased mortality explains skewed sex ratios in brown trout embryos

    Science.gov (United States)

    Labbé, L.

    2016-01-01

    Juvenile sex ratios are often assumed to be equal for many species with genetic sex determination, but this has rarely been tested in fish embryos due to their small size and absence of sex-specific markers. We artificially crossed three populations of brown trout and used a recently developed genetic marker for sexing the offspring of both pure and hybrid crosses. Sex ratios (SR = proportion of males) varied widely one month after hatching ranging from 0.15 to 0.90 (mean = 0.39 ± 0.03). Families with high survival tended to produce balanced or male-biased sex ratios, but SR was significantly female-biased when survival was low, suggesting that males sustain higher mortality during development. No difference in SR was found between pure and hybrid families, but the existence of sire × dam interactions suggests that genetic incompatibility may play a role in determining sex ratios. Our findings have implications for animal breeding and conservation because skewed sex ratios will tend to reduce effective population size and bias selection estimates. PMID:27928001

  4. Effect of Slot Combination and Skewed Slot on Electromagnetic Vibration of Capacitor Motor under Load

    Science.gov (United States)

    Hirotsuka, Isao; Tsuboi, Kazuo

    The capacitor motor (CRM) is widely used to drive industrial equipments and electric home appliances. Recently, the reduction in the vibration and noise of the CRM has become increasingly important from the standpoint of environmental improvement. However, the electromagnetic vibration of the CRM under load has not been analyzed sufficiently. Therefore, we have studied the electromagnetic vibration of CRM for the purpose of reducing it. In a previous paper, the relationships for a backward magnetic field, the equivalent circuit current, and the vibration of the CRM were clarified. The present paper theoretically and experimentally discusses the effect of the slot combination and skewed slot on the electromagnetic vibration of CRM under load. The primary conclusions are as follows: (1) In the case of 4-pole and 6-pole CRMs, the dominant electromagnetic vibration of CRMs was theoretically attributed to three types of electromagnetic force waves. Two types of electromagnetic force waves are generated: one wave is generated by the interaction of two forward magnetic fluxes, such as those of a three-phase squirrel-cage induction motor, and the other wave is generated under the influence of a backward magnetic flux. (2) The characteristics of dominant electromagnetic vibration depending on load and running capacitor were classified theoretically and experimentally into three types based on the characteristics of the electromagnetic force wave and equivalent circuit current. (3) The influences of magnetic saturation in dominant electromagnetic vibration were verified experimentally and their causes were clarified theoretically in relation to electromagnetic force waves.

  5. Bacterial clearance reverses a skewed T-cell repertoire induced by Salmonella infection.

    Science.gov (United States)

    Leyva-Rangel, Jessica P; de Los Angeles Hernández-Cueto, Maria; Galan-Enriquez, Carlos-Samuel; López-Medina, Marcela; Ortiz-Navarrete, Vianney

    2015-09-01

    Salmonella typhimurium invades the spleen, liver, and peripheral lymph nodes and has recently been detected in the bone marrow and thymus, resulting in a reduced thymic size and a decline in the total number of thymic cells. A specific deletion of the double-positive cell subset has been characterized, yet the export of mature T cells to the periphery remains normal. We analyzed Salmonella pathogenesis regarding thymic structure and the T-cell maturation process. We demonstrate that, despite alterations in the thymic structure, T-cell development is maintained during Salmonella infection, allowing the selection of single-positive T-cell clones expressing particular T-cell receptor beta chains (TCR-Vβ). Moreover, the treatment of infected mice with an antibiotic restored the normal thymic architecture and thymocyte subset distribution. Additionally, the frequency of TCR-Vβ usage after treatment was comparable to that in non-infected mice. However, bacteria were still recovered from the thymus after 1 month of treatment. Our data reveal that a skewed T-cell developmental process is present in the Salmonella-infected thymus that alters the TCR-Vβ usage frequency. Likewise, the post-treatment persistence of Salmonella reveals a novel function of the thymus as a potential reservoir for this infectious agent.

  6. Viruses-to-mobile genetic elements skew in the deep Atlantis II brine pool sediments.

    Science.gov (United States)

    Adel, Mustafa; Elbehery, Ali H A; Aziz, Sherry K; Aziz, Ramy K; Grossart, Hans-Peter; Siam, Rania

    2016-09-06

    The central rift of the Red Sea has 25 brine pools with different physical and geochemical characteristics. Atlantis II (ATIID), Discovery Deeps (DD) and Chain Deep (CD) are characterized by high salinity, temperature and metal content. Several studies reported microbial communities in these brine pools, but few studies addressed the brine pool sediments. Therefore, sediment cores were collected from ATIID, DD, CD brine pools and an adjacent brine-influenced site. Sixteen different lithologic sediment sections were subjected to shotgun DNA pyrosequencing to generate 1.47 billion base pairs (1.47 × 10(9) bp). We generated sediment-specific reads and attempted to annotate all reads. We report the phylogenetic and biochemical uniqueness of the deepest ATIID sulfur-rich brine pool sediments. In contrary to all other sediment sections, bacteria dominate the deepest ATIID sulfur-rich brine pool sediments. This decrease in virus-to-bacteria ratio in selected sections and depth coincided with an overrepresentation of mobile genetic elements. Skewing in the composition of viruses-to-mobile genetic elements may uniquely contribute to the distinct microbial consortium in sediments in proximity to hydrothermally active vents of the Red Sea and possibly in their surroundings, through differential horizontal gene transfer.

  7. Numerical Analysis of the High Skew Propeller of an Underwater Vehicle

    Institute of Scientific and Technical Information of China (English)

    Hassan Ghasseni; Parviz Ghadimi

    2011-01-01

    A numerical analysis based on the boundary element method (BEM) was presented for the hydrodynamic performance of a high skew propeller (HSP) which is employed by an underwater vehicle (UV).Since UVs operate at two different working conditions (surface and submerged conditions),the design of such a propeller is a cumbersome task.This is primarily due to the fact that the resistance forces as well as the vessel efficiency under these conditions are significantly different.Therefore,some factors are necessary for the design of the optimum propeller to utilize the power at the mentioned conditions.The design objectives of the optimum propeller are to obtain the highest possible thrust,minimum torque,and efficiency.In the current study,a 5-bladed HSP was chosen for running the UV.This propeller operated at the stem of the UV hull where the inflow velocity to the propeller was non-uniform.Some parameters of the propeller were predicted based on the UV geometrical hull and operating conditions.The computed results include the pressure distribution and the hydrodynamic characteristics of the HSP in open water conditions,and comparison of these results with those of the experimental data indicates good agreement.The propeller efficiency for both submerged and surface conditions was found to be 67% and 64%,respectively,which compared to conventional propellers is a significantly higher efficiency.

  8. Few Skewed Disks Found in First Closure-Phase Survey of Herbig Ae/Be stars

    CERN Document Server

    Monnier, J D; Millan-Gabet, R; Traub, W; Schloerb, F P; Pedretti, E; Benisty, M; Carleton, N P; Haguenauer, P; Kern, P; Labeye, P; Lacasse, M G; Malbet, F; Perraut, K; Pearlman, M; Zhao, M

    2006-01-01

    Using the 3-telescope IOTA interferometer on Mt. Hopkins, we report results from the first near-infrared (lambda=1.65 mu) closure-phase survey of Young Stellar Objects (YSOs). These closure phases allow us to unambiguously detect departures from centrosymmetry (i.e., skew) in the emission pattern from YSO disks on the scale of ~4 milliarcseconds, expected from generic ``flared disk'' models. Six of fourteen targets showed small, yet statistically-significant, non-zero closure phases, with largest values from the young binary system MWC 361-A and the (pre-main sequence?) Be star HD 45677. Our observations are quite sensitive to the vertical structure of the inner disk and we confront the predictions of the ``puffed-up inner wall'' models of Dullemond, Dominik, and Natta (DDN). Our data support disks models with curved inner rims because the expected emission appear symmetrically-distributed around the star over a wide range of inclination angles. In contrast, our results are incompatible with the models posses...

  9. Viruses-to-mobile genetic elements skew in the deep Atlantis II brine pool sediments

    Science.gov (United States)

    Adel, Mustafa; Elbehery, Ali H. A.; Aziz, Sherry K.; Aziz, Ramy K.; Grossart, Hans-Peter; Siam, Rania

    2016-09-01

    The central rift of the Red Sea has 25 brine pools with different physical and geochemical characteristics. Atlantis II (ATIID), Discovery Deeps (DD) and Chain Deep (CD) are characterized by high salinity, temperature and metal content. Several studies reported microbial communities in these brine pools, but few studies addressed the brine pool sediments. Therefore, sediment cores were collected from ATIID, DD, CD brine pools and an adjacent brine-influenced site. Sixteen different lithologic sediment sections were subjected to shotgun DNA pyrosequencing to generate 1.47 billion base pairs (1.47 × 109 bp). We generated sediment-specific reads and attempted to annotate all reads. We report the phylogenetic and biochemical uniqueness of the deepest ATIID sulfur-rich brine pool sediments. In contrary to all other sediment sections, bacteria dominate the deepest ATIID sulfur-rich brine pool sediments. This decrease in virus-to-bacteria ratio in selected sections and depth coincided with an overrepresentation of mobile genetic elements. Skewing in the composition of viruses-to-mobile genetic elements may uniquely contribute to the distinct microbial consortium in sediments in proximity to hydrothermally active vents of the Red Sea and possibly in their surroundings, through differential horizontal gene transfer.

  10. Adjusting to the Emergent

    DEFF Research Database (Denmark)

    Revsbæk, Line

    In her doctoral thesis Line Revsbaek explores newcomer innovation related to organizational entry processes in a changing organization. She introduces process philosophy and complexity theory to research on organizational socialization and newcomer innovation. The study challenges assumptions...... in standardized induction programs where newcomers are cast in roles as insecure novices needing to be “taught the ropes” of the organizational culture. Linked with this, it is suggested that the prevailing dichotomy of ‘newcomer assimilation’ versus ‘organizational accommodation’ is replaced with a notion...... of ‘adjusting to the emergent’. Newcomer innovation is portrayed as carrying a variety of possible significations, such as unintentional innovation effects of newcomer’s proactive self-socializing behavior; an inspirational basis for designing innovation-generating employee induction; ‘resonant instances...

  11. Distributions of the largest singular values of skew-symmetric random matrices and their applications to paired comparisons

    CERN Document Server

    Kuriki, Satoshi

    2010-01-01

    Let $A$ be a real skew-symmetric Gaussian random matrix whose upper triangular elements are independently distributed according to the standard normal distribution. We provide the distribution of the largest singular value $\\sigma_1$ of $A$. Moreover, by acknowledging the fact that the largest singular value can be regarded as the maximum of a Gaussian field, we deduce the distribution of the standardized largest singular value $\\sigma_1/\\sqrt{\\mathrm{tr}(A'A)/2}$. These distributional results are utilized in Scheff\\'{e}'s paired comparisons model. We propose tests for the hypothesis of subtractivity based on the largest singular value of the skew-symmetric residual matrix. Professional baseball league data are analyzed as an illustrative example.

  12. Derivative matrices of a skew ray for spherical boundary surfaces and their applications in system analysis and design.

    Science.gov (United States)

    Lin, Psang Dain

    2014-05-10

    In a previous paper [Appl. Opt.52, 4151 (2013)], we presented the first- and second-order derivatives of a ray for a flat boundary surface to design prisms. In this paper, that scheme is extended to determine the Jacobian and Hessian matrices of a skew ray as it is reflected/refracted at a spherical boundary surface. The validity of the proposed approach as an analysis and design tool is demonstrated using an axis-symmetrical system for illustration purpose. It is found that these two matrices can provide the search direction used by existing gradient-based schemes to minimize the merit function during the optimization stage of the optical system design process. It is also possible to make the optical system designs more automatic, if the image defects can be extracted from the Jacobian and Hessian matrices of a skew ray.

  13. Effects of within-colony competition on body size asymmetries and reproductive skew in a social spider

    DEFF Research Database (Denmark)

    Grinsted, Lena; Bilde, Trine

    2013-01-01

    theoretical models suggest that reproductive skew is a result of contest competition within colonies, leading to size hierarchies where only the largest females become reproducers. We investigated the effect of competition on within-group body size variation over six months in S. dumicola, by manipulating......Reproductive partitioning is a key component of social organization in groups of cooperative organisms. In colonies of permanently social spiders of the genus Stegodyphus less than half of the females reproduce, while all females, including nonreproducers, perform suicidal allo-maternal care. Some...... food level and colony size. We found no evidence that competition leads to increased size asymmetry within colonies, suggesting that contest competition may not be the proximate explanation for reproductive skew. Within-colony body size variation was high already in the juvenile stage, and did...

  14. Development and Validation of a New Blade Element Momentum Skewed-Wake Model within AeroDyn: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Ning, S. A.; Hayman, G.; Damiani, R.; Jonkman, J.

    2014-12-01

    Blade element momentum methods, though conceptually simple, are highly useful for analyzing wind turbines aerodynamics and are widely used in many design and analysis applications. A new version of AeroDyn is being developed to take advantage of new robust solution methodologies, conform to a new modularization framework for National Renewable Energy Laboratory's FAST, utilize advanced skewed-wake analysis methods, fix limitations with previous implementations, and to enable modeling of highly flexible and nonstraight blades. This paper reviews blade element momentum theory and several of the options available for analyzing skewed inflow. AeroDyn implementation details are described for the benefit of users and developers. These new options are compared to solutions from the previous version of AeroDyn and to experimental data. Finally, recommendations are given on how one might select from the various available solution approaches.

  15. Adolescent Mothers' Adjustment to Parenting.

    Science.gov (United States)

    Samuels, Valerie Jarvis; And Others

    1994-01-01

    Examined adolescent mothers' adjustment to parenting, self-esteem, social support, and perceptions of baby. Subjects (n=52) responded to questionnaires at two time periods approximately six months apart. Mothers with higher self-esteem at Time 1 had better adjustment at Time 2. Adjustment was predicted by Time 2 variables; contact with baby's…

  16. Adolescent Mothers' Adjustment to Parenting.

    Science.gov (United States)

    Samuels, Valerie Jarvis; And Others

    1994-01-01

    Examined adolescent mothers' adjustment to parenting, self-esteem, social support, and perceptions of baby. Subjects (n=52) responded to questionnaires at two time periods approximately six months apart. Mothers with higher self-esteem at Time 1 had better adjustment at Time 2. Adjustment was predicted by Time 2 variables; contact with baby's…

  17. Using rank-order geostatistics for spatial interpolation of highly skewed data in a heavy-metal contaminated site.

    Science.gov (United States)

    Juang, K W; Lee, D Y; Ellsworth, T R

    2001-01-01

    The spatial distribution of a pollutant in contaminated soils is usually highly skewed. As a result, the sample variogram often differs considerably from its regional counterpart and the geostatistical interpolation is hindered. In this study, rank-order geostatistics with standardized rank transformation was used for the spatial interpolation of pollutants with a highly skewed distribution in contaminated soils when commonly used nonlinear methods, such as logarithmic and normal-scored transformations, are not suitable. A real data set of soil Cd concentrations with great variation and high skewness in a contaminated site of Taiwan was used for illustration. The spatial dependence of ranks transformed from Cd concentrations was identified and kriging estimation was readily performed in the standardized-rank space. The estimated standardized rank was back-transformed into the concentration space using the middle point model within a standardized-rank interval of the empirical distribution function (EDF). The spatial distribution of Cd concentrations was then obtained. The probability of Cd concentration being higher than a given cutoff value also can be estimated by using the estimated distribution of standardized ranks. The contour maps of Cd concentrations and the probabilities of Cd concentrations being higher than the cutoff value can be simultaneously used for delineation of hazardous areas of contaminated soils.

  18. Effects of within-colony competition on body size asymmetries and reproductive skew in a social spider.

    Science.gov (United States)

    Grinsted, L; Bilde, T

    2013-03-01

    Reproductive partitioning is a key component of social organization in groups of cooperative organisms. In colonies of permanently social spiders of the genus Stegodyphus less than half of the females reproduce, while all females, including nonreproducers, perform suicidal allo-maternal care. Some theoretical models suggest that reproductive skew is a result of contest competition within colonies, leading to size hierarchies where only the largest females become reproducers. We investigated the effect of competition on within-group body size variation over six months in S. dumicola, by manipulating food level and colony size. We found no evidence that competition leads to increased size asymmetry within colonies, suggesting that contest competition may not be the proximate explanation for reproductive skew. Within-colony body size variation was high already in the juvenile stage, and did not increase over the course of the experiment, suggesting that body size variation is shaped at an early stage. This might facilitate task specialization within colonies and ensure colony-level reproductive output by early allocation of reproductive roles. We suggest that reproductive skew in social spiders may be an adaptation to sociality selected through inclusive fitness benefits of allo-maternal care as well as colony-level benefits maximizing colony survival and production.

  19. The power of multiple battery factor analysis in coping with the effects of differential skewness of variables

    Directory of Open Access Journals (Sweden)

    Johann M. Schepers

    2004-10-01

    Full Text Available The principal objective of the study was to determine the power of Multiple Battery Factor Analysis (MBFA in coping with the effects of differential skewness of the variables used. Generally speaking, joint analyses result in factors of skewness. To examine the problem the General Scholastic Aptitude Test (GSAT and Senior Ability Tests (SAT were jointly applied to a sample of 1 598 first-year university students, and subjected to both a Principal Factor Analysis (PFA and a MBFA. Three factors were obtained in both instances. The PFA yielded factors of skewness and the MBFA factors of content. The implications of the findings are discussed. Opsomming Die hoofdoelwit van die studie was om die krag van Veelvuldigebattery-faktorontleding (VBFO te bepaal ten einde die gevolge van differensiële skeefheid van veranderlikes te bowe te kom. In die algemeen lei gesamentlike faktorontledings van batterye toetse tot faktore van skeefheid. Om die probleem te ondersoek, is die Algemene Skolastiese Aanlegtoets (ASAT en die Senior Aanlegtoetse (SAT gesamentlik op ’n steekproef van 1 598 eerstejaaruniversiteitstudente toegepas en aan sowel ’n Hooffaktorontleding (HFO as ’n VBFO onderwerp. Drie faktore is in albei gevalle verkry. Die HFO het faktore van skeefheid opgelewer en die VBFO faktore van inhoud. Die implikasies van die bevindinge word bespreek.

  20. De novo MECP2 duplications in two females with intellectual disability and unfavorable complete skewed X-inactivation.

    Science.gov (United States)

    Fieremans, Nathalie; Bauters, Marijke; Belet, Stefanie; Verbeeck, Jelle; Jansen, Anna C; Seneca, Sara; Roelens, Filip; De Baere, Elfride; Marynen, Peter; Froyen, Guy

    2014-11-01

    Xq28 microduplications of MECP2 are a prominent cause of a severe syndromic form of intellectual disability (ID) in males. Females are usually unaffected through near to complete X-inactivation of the aberrant X chromosome (skewing). In rare cases, affected females have been described due to random X-inactivation. Here, we report on two female patients carrying de novo MECP2 microduplications on their fully active X chromosomes. Both patients present with ID and additional clinical features. Mono-allelic expression confirmed complete skewing of X-inactivation. Consequently, significantly enhanced MECP2 mRNA levels were observed. We hypothesize that the cause for the complete skewing is due to a more harmful mutation on the other X chromosome, thereby forcing the MECP2 duplication to become active. However, we could not unequivocally identify such a second mutation by array-CGH or exome sequencing. Our data underline that, like in males, increased MECP2 dosage in females can contribute to ID too, which should be taken into account in diagnostics.

  1. The Design and Implementation of a Novel Skew Scenario Model in Mobile Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    N. Vetrivelan

    2010-01-01

    Full Text Available Problem statement: In this research, it had been presented a novel Skew Scenario Model that has been developed and implemented for mobile ad hoc networks. There exist several mobility patterns that try to capture the behavior of the mobile devices under different circumstances, whereas in our work, the direction movement of the nodes is significantly specified horizontally, vertically and diagonally in the simulation area. Approach: Our novel Skew Scenario Model and the impact of mobility on MANET protocols had been compared and analyzed. The performance of DSDV and DSR under SSM in terms of packet delivery fraction, routing load and latency for varying source and destination traffic from 10, 20, 30, 40 and 50 under 100 nodes environment had been analyzed. Apart from this, our SSM with the existing waypoint model in 100 nodes environment had been compared. A suitable algorithm for SSM has also been developed. Results: Our simulation result showed that the functioning of our SSM had greatly influenced the performance of routing protocols in MANET environment. Simulation experiments confirm that for DSR under SSM, the PDF is highest between 93.56-99.43%, routing load is lowest between 1.005-1.068 and Latency is very less between 0.0163-0.049 sec, in the case of DSDV under SSM, the PDF is 63.22-79.104%, routing load is 1.20-1.58 and latency is 0.018-0.050 sec. The result revealed the fact that the reactive routing protocol DSR outperforms much more than the Proactive routing protocol DSDV. Our Novel Model has performed well when we compared it with existing waypoint mobility model while setting many source-destination connections. In DSR under SSM and waypoint model, PDF is between 93.56-99.43% in SSM and in waypoint 94.20-98.88%. Routing load in SSM is 1.0056-1.068, waypoint 1.01-1.06 seconds. Latency is between 0.026-0.063 in SSM and in waypoint 0.026-0.1235 sec. Conclusion: This study revealed the fact that the DSR discovers new routes faster

  2. Re-identification of home addresses from spatial locations anonymized by Gaussian skew

    Directory of Open Access Journals (Sweden)

    Cassa Christopher A

    2008-08-01

    Full Text Available Abstract Background Knowledge of the geographical locations of individuals is fundamental to the practice of spatial epidemiology. One approach to preserving the privacy of individual-level addresses in a data set is to de-identify the data using a non-deterministic blurring algorithm that shifts the geocoded values. We investigate a vulnerability in this approach which enables an adversary to re-identify individuals using multiple anonymized versions of the original data set. If several such versions are available, each can be used to incrementally refine estimates of the original geocoded location. Results We produce multiple anonymized data sets using a single set of addresses and then progressively average the anonymized results related to each address, characterizing the steep decline in distance from the re-identified point to the original location, (and the reduction in privacy. With ten anonymized copies of an original data set, we find a substantial decrease in average distance from 0.7 km to 0.2 km between the estimated, re-identified address and the original address. With fifty anonymized copies of an original data set, we find a decrease in average distance from 0.7 km to 0.1 km. Conclusion We demonstrate that multiple versions of the same data, each anonymized by non-deterministic Gaussian skew, can be used to ascertain original geographic locations. We explore solutions to this problem that include infrastructure to support the safe disclosure of anonymized medical data to prevent inference or re-identification of original address data, and the use of a Markov-process based algorithm to mitigate this risk.

  3. COMPENDEX Profile Adjustment Manual.

    Science.gov (United States)

    Standera, Oldrich

    If an information system is to survive, the users must be satisfied that it meets their needs promptly and consistently. It is essential to react quickly to any undesired result such as an extemely high or low output, too low a relevance or recall, or both. The search editor should feel responsbile not only for the profile setup but also for its…

  4. A Third Moment Adjusted Test Statistic for Small Sample Factor Analysis.

    Science.gov (United States)

    Lin, Johnny; Bentler, Peter M

    2012-01-01

    Goodness of fit testing in factor analysis is based on the assumption that the test statistic is asymptotically chi-square; but this property may not hold in small samples even when the factors and errors are normally distributed in the population. Robust methods such as Browne's asymptotically distribution-free method and Satorra Bentler's mean scaling statistic were developed under the presumption of non-normality in the factors and errors. This paper finds new application to the case where factors and errors are normally distributed in the population but the skewness of the obtained test statistic is still high due to sampling error in the observed indicators. An extension of Satorra Bentler's statistic is proposed that not only scales the mean but also adjusts the degrees of freedom based on the skewness of the obtained test statistic in order to improve its robustness under small samples. A simple simulation study shows that this third moment adjusted statistic asymptotically performs on par with previously proposed methods, and at a very small sample size offers superior Type I error rates under a properly specified model. Data from Mardia, Kent and Bibby's study of students tested for their ability in five content areas that were either open or closed book were used to illustrate the real-world performance of this statistic.

  5. Convexity Adjustments for ATS Models

    DEFF Research Database (Denmark)

    Murgoci, Agatha; Gaspar, Raquel M.

    Practitioners are used to value a broad class of exotic interest rate derivatives simply by preforming for what is known as convexity adjustments (or convexity corrections). We start by exploiting the relations between various interest rate models and their connections to measure changes. As a re......Practitioners are used to value a broad class of exotic interest rate derivatives simply by preforming for what is known as convexity adjustments (or convexity corrections). We start by exploiting the relations between various interest rate models and their connections to measure changes....... As a result we classify convexity adjustments into forward adjustments and swaps adjustments. We, then, focus on affine term structure (ATS) models and, in this context, conjecture convexity adjustments should be related of affine functionals. In the case of forward adjustments, we show how to obtain exact...... formulas. Concretely for LIBOR in arrears (LIA) contracts, we derive the system of Riccatti ODE-s one needs to compute to obtain the exact adjustment. Based upon the ideas of Schrager and Pelsser (2006) we are also able to derive general swap adjustments useful, in particular, when dealing with constant...

  6. 基于MRS Copula-GJR-Skewed-t模型的股指期货套期保值研究%Hedging of stock index futures based on Markov regime-switching Copula-GJR-Skewed-t model

    Institute of Scientific and Technical Information of China (English)

    谢赤; 余聪; 罗长青; 王纲金

    2013-01-01

    构建了一个基于马尔可夫状态转换Copula函数的GJR-Skew-t模型,用以估计4个亚洲证券市场中股指期货与指数现货之间的最小方差套期保值比率.实证研究表明:动态套期保值模型的风险规避效果明显优于静态模型;根据套期保值组合方差降低百分比,该模型套期保值效果比其它动态策略有显著提升;除日本市场外,基于马尔可夫状态转换Copula函数的套期保值模型可以获得比传统模型更高的收益,这意味着该策略模型有助于降低套期保值成本.%This paper constructs a GJR-Skew-t model based on Copula functions with Markov regime switching to estimate the minimum variance hedging ratio between the returns of stock index futures and spots in four Asian markets. The empirical results show that the risk mitigation degree of the dynamic hedging models is higher than that of the static models. Based on the analysis of the variance reduction of hedging portfolio, the dynamic models are more effective than other models. Moreover, the proposed Markov regime-switching Copula-GJR-Skewed-t model can gain higher revenues than the traditional models except for the Japanese market, which means that our model contributes to reduce the cost of hedging.

  7. 75 FR 45092 - Trade Adjustment Assistance for Farmers

    Science.gov (United States)

    2010-08-02

    ... Foreign Agricultural Service Trade Adjustment Assistance for Farmers AGENCY: Foreign Agricultural Service.... FOR FURTHER INFORMATION CONTACT: Trade Adjustment Assistance for Farmers Program Staff, FAS, USDA by... TAA for Farmers' Web site: http://www.fas.usda.gov/itp/taa . Dated: July 21, 2010. John D....

  8. 75 FR 48931 - Trade Adjustment Assistance for Farmers

    Science.gov (United States)

    2010-08-12

    ... Foreign Agricultural Service Trade Adjustment Assistance for Farmers AGENCY: Foreign Agricultural Service... FURTHER INFORMATION CONTACT: Trade Adjustment Assistance for Farmers Program Staff, FAS, USDA by phone... Farmers' Web site: www.fas.usda.gov/itp/taa . Dated: July 30, 2010. John D. Brewer, Administrator,...

  9. 75 FR 49458 - Trade Adjustment Assistance for Farmers

    Science.gov (United States)

    2010-08-13

    ... Foreign Agricultural Service Trade Adjustment Assistance for Farmers AGENCY: Foreign Agricultural Service.... FOR FURTHER INFORMATION CONTACT: Trade Adjustment Assistance for Farmers Program Staff, FAS, USDA by... TAA for Farmers' Web site: http://www.fas.usda.gov/itp/taa . Dated: August 3, 2010. Suzanne...

  10. 75 FR 43140 - Trade Adjustment Assistance for Farmers

    Science.gov (United States)

    2010-07-23

    ... Foreign Agricultural Service Trade Adjustment Assistance for Farmers AGENCY: Foreign Agricultural Service... assistance and cash benefits. FOR FURTHER INFORMATION CONTACT: Trade Adjustment Assistance for Farmers Staff... ; or visit the TAA for Farmers' Web site: http://www.fas.usda.gov/itp/taa . Dated: July 14, 2010....

  11. Intertrial priming of pop-out search influences the shift, skew, and dispersion of response time distributions.

    Science.gov (United States)

    Burnham, Bryan R; Cilento, James J; Hanley, Bridget

    2015-08-01

    Priming of pop-out (PoP), or intertrial priming, is the finding that responding to a singleton target is faster when a target's defining feature (e.g., color) and nontarget features are repeated between trials than when the target and nontarget features switch between trials. Facilitated responding may reflect priming's influence on selection, that is,  implicitly encoded features speed the selection of a matching target. In contrast, PoP effects may also reflect intertrial priming's influence on postselection processes, where episodic retrieval of a previous target is facilitated when its features match the current target. Lamy, Yashar, and Ruderman Attention, Perception, & Psychophysics, 73, 2160-2167 (2011) proposed a hybrid, dual-stage model that assumes intertrial priming influences both selection and postselection retrieval. To provide support for intertrial priming influencing more than one cognitive process, we examined priming's influence on the shift, skew, and dispersion of RT distributions in PoP tasks by fitting the exponential-Gaussian function to the RTs. Three experiments demonstrated that PoP effects at the level of mean RT were associated with changes in both the shift and skew of the underlying RT distributions. Importantly, Experiments 2 and 3 showed that manipulations intended to influence selection or postselection processes produced corresponding changes in the contributions of the distribution shift and skew to the PoP effects on mean RT. The results suggest more than one process is influenced by intertrial priming in visual search tasks, but readers should be cautious about relating specific processes to specific exponential-Gaussian parameters.

  12. Mood Adjustment via Mass Communication.

    Science.gov (United States)

    Knobloch, Silvia

    2003-01-01

    Proposes and experimentally tests mood adjustment approach, complementing mood management theory. Discusses how results regarding self-exposure across time show that patterns of popular music listening among a group of undergraduate students differ with initial mood and anticipation, lending support to mood adjustment hypotheses. Describes how…

  13. Spousal Adjustment to Myocardial Infarction.

    Science.gov (United States)

    Ziglar, Elisa J.

    This paper reviews the literature on the stresses and coping strategies of spouses of patients with myocardial infarction (MI). It attempts to identify specific problem areas of adjustment for the spouse and to explore the effects of spousal adjustment on patient recovery. Chapter one provides an overview of the importance in examining the…

  14. A complete generalized adjustment criterion

    NARCIS (Netherlands)

    Perković, Emilija; Textor, Johannes; Kalisch, Markus; Maathuis, Marloes H.

    2015-01-01

    Covariate adjustment is a widely used approach to estimate total causal effects from observational data. Several graphical criteria have been developed in recent years to identify valid covariates for adjustment from graphical causal models. These criteria can handle multiple causes, latent confound

  15. Bayes linear covariance matrix adjustment

    CERN Document Server

    Wilkinson, Darren J

    1995-01-01

    In this thesis, a Bayes linear methodology for the adjustment of covariance matrices is presented and discussed. A geometric framework for quantifying uncertainties about covariance matrices is set up, and an inner-product for spaces of random matrices is motivated and constructed. The inner-product on this space captures aspects of our beliefs about the relationship between covariance matrices of interest to us, providing a structure rich enough for us to adjust beliefs about unknown matrices in the light of data such as sample covariance matrices, exploiting second-order exchangeability and related specifications to obtain representations allowing analysis. Adjustment is associated with orthogonal projection, and illustrated with examples of adjustments for some common problems. The problem of adjusting the covariance matrices underlying exchangeable random vectors is tackled and discussed. Learning about the covariance matrices associated with multivariate time series dynamic linear models is shown to be a...

  16. Parental Divorce and Children's Adjustment.

    Science.gov (United States)

    Lansford, Jennifer E

    2009-03-01

    This article reviews the research literature on links between parental divorce and children's short-term and long-term adjustment. First, I consider evidence regarding how divorce relates to children's externalizing behaviors, internalizing problems, academic achievement, and social relationships. Second, I examine timing of the divorce, demographic characteristics, children's adjustment prior to the divorce, and stigmatization as moderators of the links between divorce and children's adjustment. Third, I examine income, interparental conflict, parenting, and parents well-being as mediators of relations between divorce and children's adjustment. Fourth, I note the caveats and limitations of the research literature. Finally, I consider notable policies related to grounds for divorce, child support, and child custody in light of how they might affect children s adjustment to their parents divorce.

  17. A Chaos-based Image Encryption Scheme Using 3D Skew Tent Map and Coupled Map Lattice

    Directory of Open Access Journals (Sweden)

    Ruisong Ye

    2012-02-01

    Full Text Available This paper proposes a chaos-based image encryption scheme where one 3D skew tent map with three control parameters is utilized to generate chaotic orbits applied to scramble the pixel positions while one coupled map lattice is employed to yield random gray value sequences to change the gray values so as to enhance the security. Experimental results have been carried out with detailed analysis to demonstrate that the proposed image encryption scheme possesses large key space to resist brute-force attack and possesses good statistical properties to frustrate statistical analysis attacks. Experiments are also performed to illustrate the robustness against malicious attacks like cropping, noising, JPEG compression.

  18. Wave steering effects in anisotropic composite structures: Direct calculation of the energy skew angle through a finite element scheme.

    Science.gov (United States)

    Chronopoulos, D

    2017-01-01

    A systematic expression quantifying the wave energy skewing phenomenon as a function of the mechanical characteristics of a non-isotropic structure is derived in this study. A structure of arbitrary anisotropy, layering and geometric complexity is modelled through Finite Elements (FEs) coupled to a periodic structure wave scheme. A generic approach for efficiently computing the angular sensitivity of the wave slowness for each wave type, direction and frequency is presented. The approach does not involve any finite differentiation scheme and is therefore computationally efficient and not prone to the associated numerical errors.

  19. Mapping Causes and Implications of India’s Skewed Sex Ratio and Poverty problem using Fuzzy & Neutrosophic Relational Maps

    Directory of Open Access Journals (Sweden)

    Gaurav

    2016-08-01

    Full Text Available Numerous studies by different researchers have confirmed that skewed sex ratio is a critical social problem in India. This enduring problem of gender imbalance is the collective result of factors like sex selective abortion, gender discrimination, son preference for the preservation of tribe, emergence of new technologies in medical field and many more factors. Another severe problem to be addressed in India is poverty. Many factors contribute to the perpetuation of poverty such as illiteracy, bad governance, under employment and various other reasons. Despite of India's accelerated growth rate, poverty in India is still prevalent.

  20. Pre-operative perfusion skewness and kurtosis are potential predictors of progression-free survival after partial resection of newly diagnosed glioblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Paik, Wo Yul [Dept. of Radiology, Dankook University Hospital, Cheonan (Korea, Republic of); Kim, Ho Sung; Choi, Choong Gon; Kim, Sang Joon [Dept. of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of)

    2016-02-15

    To determine whether pre-operative perfusion skewness and kurtosis derived from normalized cerebral blood volume (nCBV) histograms are associated with progression-free survival (PFS) of patients after partial resection of newly diagnosed glioblastoma. A total of 135 glioblastoma patients who had undergone partial resection of tumor (resection of < 50% of pre-operative tumor volume or surgical biopsy) confirmed with immediate postsurgical MRI and examined with both conventional MRI and dynamic susceptibility contrast (DSC) perfusion MRI before the surgery were retrospectively reviewed in this study. They had been followed up post-surgical chemoradiotherapy for tumor progression. Using histogram analyses of nCBV derived from pre-operative DSC perfusion MRI, patients were sub-classified into the following four groups: positive skewness and leptokurtosis (group 1); positive skewness and platykurtosis (group 2); negative skewness and leptokurtosis (group 3); negative skewness and platykurtosis (group 4). Kaplan-Meier analysis and multivariable Cox proportional hazards regression analysis were performed to determine whether clinical and imaging covariates were associated with PFS or overall survival (OS) of these patients. According to the Kaplan-Meier method, median PFS of group 1, 2, 3, and 4 was 62, 51, 39, and 41 weeks, respectively, with median OS of 82, 77, 77, and 72 weeks, respectively. In multivariable analyses with Cox proportional hazards regression, pre-operative skewness/kurtosis pattern (hazard ratio: 2.98 to 4.64; p < 0.001), Karnofsky performance scale score (hazard ratio: 1.04; p = 0.003), and post-operative tumor volume (hazard ratio: 1.04; p = 0.02) were independently associated with PFS but not with OS. Higher skewness and kurtosis of nCBV histogram before surgery were associated with longer PFS in patients with newly diagnosed glioblastoma after partial tumor resection.

  1. Child adjustment in high conflict families.

    Science.gov (United States)

    Smith, J; Berthelsen, D; O'Connor, I

    1997-03-01

    Children exposed to spousal violence are at risk for social-emotional problems. This research investigated a number of family and child factors which might influence the effects of witnessing spousal violence on young children. Fifty-four mothers who had at least one child in the age range of 3 to 6 years participated in the study. These women had left a violent relationship 12 to 24 months prior to their participation in the study and were not in a new relationship. Information was collected through a structured interview which included the administration of a standardized family violence measure (conflict tactics scale) and child adjustment profile (child behaviour checklist). Forty-two per cent of the children exhibited a level of behavioural problems which would warrant clinical intervention. The amount of violence that the children witnessed, the children's responses when the violence occurred and whether the child copied the violent partner's behaviour, were associated with the children's behavioural adjustment scores. Maternal parenting style was not found to have a significant effect on behavioural adjustment. The study provided important quantitative and qualitative data on the nature of parent-child relationships and children's adjustment in families where there is spousal violence.

  2. Managing psychosocial adjustment to aphasia.

    Science.gov (United States)

    Müller, D

    1999-01-01

    This article argues for incorporating psychosocial adjustment into treatment plans for people with aphasia. It proposes that rehabilitation is a social rather than a medical construct and that by adopting a broad range of intervention strategies, more effective approaches to reintegration can be adopted. Outcome measures relating to self-esteem are judged to be central to evaluating the efficacy of treatment. The role of social factors in managing psychosocial adjustment are considered alongside individual and family approaches to counseling. It is concluded that clinicians need to broaden their treatment program to include psychosocial adjustment in rehabilitation.

  3. Stock markets volatility spillovers during financial crises: A DCC-MGARCH with skewed-t density approach

    Directory of Open Access Journals (Sweden)

    Dahiru A. Bala

    2017-03-01

    Full Text Available This paper investigates stock returns volatility spillovers in emerging and developed markets (DMs using multivariate-GARCH (MGARCH models and their variants. In addition, we analyse the impacts of global financial crisis (2007–2009 on stock market volatility interactions and modify the BEKK-MGARCH-type models by including financial crisis dummies to assess their impact on volatilities and spillovers. Major findings reveal that correlations among emerging markets (EMs are lower compared with correlations among DMs and increase during financial crises. Furthermore, we detect evidence of volatility spillovers and observe that own-volatility spillovers are higher than cross-volatility spillovers for EMs suggesting that shocks have not been substantially transmitted among EMs compared to DMs. We also find significant asymmetric behaviour in DMs while weak evidence is detected for EMs. Finally, the DCC-with-skewed-t density model provided improved diagnostics compared to other models partly due to its taking into account fat tails and skewed features often present in financial returns.

  4. Text/Graphics Separation and Skew Correction of Text Regions of Business Card Images for Mobile Devices

    CERN Document Server

    Mollah, Ayatullah Faruk; Nasipuri, Mita

    2010-01-01

    Separation of the text regions from background texture and graphics is an important step of any optical character recognition system for the images containing both texts and graphics. In this paper, we have presented a novel text/graphics separation technique and a method for skew correction of text regions extracted from business card images captured with a cell-phone camera. At first, the background is eliminated at a coarse level based on intensity variance. This makes the foreground components distinct from each other. Then the non-text components are removed using various characteristic features of text and graphics. Finally, the text regions are skew corrected for further processing. Experimenting with business card images of various resolutions, we have found an optimum performance of 98.25% (recall) with 0.75 MP images, that takes 0.17 seconds processing time and 1.1 MB peak memory on a moderately powerful computer (DualCore 1.73 GHz Processor, 1 GB RAM, 1 MB L2 Cache). The developed technique is comp...

  5. Bulk asymptotics of skew-orthogonal polynomials for quartic double well potential and universality in the matrix model

    CERN Document Server

    Ghosh, Saugata

    2008-01-01

    We derive bulk asymptotics of skew-orthogonal polynomials (sop) $\\pi^{\\bt}_{m}$, $\\beta=1$, 4, defined w.r.t. the weight $\\exp(-2NV(x))$, $V (x)=gx^4/4+tx^2/2$, $g>0$ and $t 0$, such that $\\epsilon\\leq (m/N)\\leq \\lambda_{\\rm cr}-\\epsilon$, where $\\lambda_{\\rm cr}$ is the critical value which separates sop with two cuts from those with one cut. Simultaneously we derive asymptotics for the recursive coefficients of skew-orthogonal polynomials. The proof is based on obtaining a finite term recursion relation between sop and orthogonal polynomials (op) and using asymptotic results of op derived in \\cite{bleher}. Finally, we apply these asymptotic results of sop and their recursion coefficients in the generalized Christoffel-Darboux formula (GCD) \\cite{ghosh3} to obtain level densities and sine-kernels in the bulk of the spectrum for orthogonal and symplectic ensembles of random matrices.

  6. Performance-based seismic assessment of skewed bridges with and without considering soil-foundation interaction effects for various site classes

    Science.gov (United States)

    Ghotbi, Abdoul R.

    2014-09-01

    The seismic behavior of skewed bridges has not been well studied compared to straight bridges. Skewed bridges have shown extensive damage, especially due to deck rotation, shear keys failure, abutment unseating and column-bent drift. This research, therefore, aims to study the behavior of skewed and straight highway overpass bridges both with and without taking into account the effects of Soil-Structure Interaction (SSI) due to near-fault ground motions. Due to several sources of uncertainty associated with the ground motions, soil and structure, a probabilistic approach is needed. Thus, a probabilistic methodology similar to the one developed by the Pacific Earthquake Engineering Research Center (PEER) has been utilized to assess the probability of damage due to various levels of shaking using appropriate intensity measures with minimum dispersions. The probabilistic analyses were performed for various bridge configurations and site conditions, including sand ranging from loose to dense and clay ranging from soft to stiff, in order to evaluate the effects. The results proved a considerable susceptibility of skewed bridges to deck rotation and shear keys displacement. It was also found that SSI had a decreasing effect on the damage probability for various demands compared to the fixed-base model without including SSI. However, deck rotation for all types of the soil and also abutment unseating for very loose sand and soft clay showed an increase in damage probability compared to the fixed-base model. The damage probability for various demands has also been found to decrease with an increase of soil strength for both sandy and clayey sites. With respect to the variations in the skew angle, an increase in skew angle has had an increasing effect on the amplitude of the seismic response for various demands. Deck rotation has been very sensitive to the increase in the skew angle; therefore, as the skew angle increased, the deck rotation responded accordingly

  7. A Comparison Study on the Performances Of X , EWMA and CUSUM Control Charts for Skewed Distributions Using Weighted Standard Deviations Methods

    Directory of Open Access Journals (Sweden)

    Abdu. M. A. Atta

    2011-12-01

    Full Text Available In many statistical process control (SPC applications, the ease of use of control charts leads to ignoring the fact that the process population of the quality characteristic being measured may be highly skewed. However, in many situations, the normality assumption is usually violated. Among the recent heuristic charts for skewed distributions proposed in the literature are those based on the weighted standard deviation (WSD method. Thus, this paper compares the performances of certain WSD charts, such as WSD X , WSD Exponential weighted moving Average (WSDEWMA and WSD Cumulative Sum (WSD-CUSUM charts for skewed distributions. The skewed distributions being considered are weibull, gamma and lognormal. The false alarm and mean shift detection rates were computed so as to evaluate the performances of the WSD charts. The WSD X chart was found to have the lowest false alarm rate in cases of known and unknown parameters. Moreover, when parameters are known and unknown, the WSD-CUSUM provided the highest mean shift detection rates. The chart with the lowest false alarm and the highest mean shift detection rates for most level of skewness and sample size, n is assumed to be have a better performance.

  8. Adjustable Induction-Heating Coil

    Science.gov (United States)

    Ellis, Rod; Bartolotta, Paul

    1990-01-01

    Improved design for induction-heating work coil facilitates optimization of heating in different metal specimens. Three segments adjusted independently to obtain desired distribution of temperature. Reduces time needed to achieve required temperature profiles.

  9. Household Adjustments to Hurricane Katrina

    National Research Council Canada - National Science Library

    Meri Davlasheridze; Qin Fan

    2017-01-01

    This paper examines household adjustments to Hurricane Katrina by estimating the effects of Katrina-induced damages on changes in household demographics and income distributions in the Orleans Parish...

  10. Yuan Exchange Rate 'Properly Adjusted'

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

      The currency exchange rate was "properly adjusted" this year and takes into account effects on the country's neighbors and the world, Premier Wen Jiabao said at a regional meeting in Malaysia.……

  11. Time-adjusted variable resistor

    Science.gov (United States)

    Heyser, R. C.

    1972-01-01

    Timing mechanism was developed effecting extremely precisioned highly resistant fixed resistor. Switches shunt all or portion of resistor; effective resistance is varied over time interval by adjusting switch closure rate.

  12. 个人理论对刻板印象相关行为信息注意加工的调节作用%The Adjustment Role of Person Theory to Process Stereotype Related Behavioral Information

    Institute of Scientific and Technical Information of China (English)

    余秋梅; 张锋

    2014-01-01

    目的:考察个人理论对性别刻板印象相关信息注意加工的调节机制.方法:翻译修订Levy等人编制的内隐个人理论测验(Implicit Person Theory Measure)作为研究筛选实验被试的工具,通过自编问卷确定实验材料,通过反应时范式考察个人理论对性别刻板印象相关信息注意分配的调节作用.结果:在高认知负荷条件下,实体论者将更多的注意资源分配于对与其刻板印象一致性信息的加工,而动态论者将更多的注意资源分配于对与其刻板印象不一致性信息的加工;在低认知负荷条件下,实体论者与动态论者对不同类型行为信息的注意分配不存在差异.结论:实体论者与动态论者对基于性别刻板印象行为信息的加工机制不同.%Objective:To explore the moderating effect of person theory on the attention processing on gender stereotype information.Methods:Implicit Person Theory Measure was translated and revised,which was used to screen the parcipants.and a self-administered questionnaire was applied to determine the experimental material.Results:Under high cognitive load,entity theorists allocated more attention to consistent information than to inconsistent information,whereas incremental theorists allocated more attention to inconsistent information than to consistent information.There were no significant differences of attention allocation for either entity theorists or incremental theorists in the low load condition.Conclusion:Person theory may influence the attentional processing on the gender stereotype information under high cognitive load conditions.

  13. Polar Factorization and Generalized Inverse for Row (Column) Skew Symmetric Matrix%行(列)反对称矩阵的极分解及其广义逆

    Institute of Scientific and Technical Information of China (English)

    袁晖坪

    2013-01-01

    The author studied the polar factorization and generalized inverse of row (column) skew symmetric matrix, which leads to some new results. In addition, the formula of the polar factorization and generalized inverse of row (column) skew symmetric matrix were given, which makes calculation easier, and some perturbation bounds of polar factorization of row (column) skew symmetric matrix were also presented.%考虑行(列)反对称矩阵的极分解和广义逆,给出了行(列)反对称矩阵的极分解和广义逆计算公式,并对行(列)反对称矩阵的极分解作了扰动分析.结果表明,所给方法既减少了计算量与存储量,又保证了数值精度.

  14. DFT及多投影分析的织物纬斜检测方法研究%Fabric Skew Detection Method Based on DFT and Multi-projection Analysis

    Institute of Scientific and Technical Information of China (English)

    董燕; 朱永胜; 张晓慧

    2013-01-01

    For fabric image skew detection,the detection accuracy is vulnerable to light and fabric texture complexity.If process the image with a lot of redundant information directly,it needs a large amount of calculation,which is not suitable for real-time detection system.This paper proposed a novel method based on DFT and multi-projection analysis on the grounds of the DFT spectrum binarization and morphological filtering experiments.This method was used to remove the redundant information of DFT spectrum of the fabric image,rotate and projecte the spectrum in small step,then detected the skew angle of the fabric image based on the fact that a maximum of projection pixels appears in the center of the spectrum if the longitudinal centerline of the spectrum is vertical to the transverse axis.The experimental results show that this algorithm has high accuracy in detecting small amount of fabric skew and better adaptability of the fabric density.%研究织物图像纬斜准确检测的问题,检测精度易受光线及织物纹理复杂性的影响,如将存在着大量冗余信息的图像直接进行处理,计算量大,不适合用实时检测系统.在对织物的DFT谱进行二值化、形态学滤波等一系列实验的基础上,提出了一种基于DFT及多投影分析的纬斜量检测方法.方法将织物图像的DFT变换谱去除冗余信息,再以较小的步长进行旋转投影,根据频谱图的纵轴与横坐标垂直时在频谱图的中心位置会出现投影像素的最大值的原理,检测出织物图像的倾斜角度.实验结果证明该算法在对小角度的纬斜量检测时,具有较高的精度,且对织物的疏密度适应性较强.

  15. Estimating the mean and standard deviation of environmental data with below detection limit observations: Considering highly skewed data and model misspecification.

    Science.gov (United States)

    Shoari, Niloofar; Dubé, Jean-Sébastien; Chenouri, Shoja'eddin

    2015-11-01

    In environmental studies, concentration measurements frequently fall below detection limits of measuring instruments, resulting in left-censored data. Some studies employ parametric methods such as the maximum likelihood estimator (MLE), robust regression on order statistic (rROS), and gamma regression on order statistic (GROS), while others suggest a non-parametric approach, the Kaplan-Meier method (KM). Using examples of real data from a soil characterization study in Montreal, we highlight the need for additional investigations that aim at unifying the existing literature. A number of studies have examined this issue; however, those considering data skewness and model misspecification are rare. These aspects are investigated in this paper through simulations. Among other findings, results show that for low skewed data, the performance of different statistical methods is comparable, regardless of the censoring percentage and sample size. For highly skewed data, the performance of the MLE method under lognormal and Weibull distributions is questionable; particularly, when the sample size is small or censoring percentage is high. In such conditions, MLE under gamma distribution, rROS, GROS, and KM are less sensitive to skewness. Related to model misspecification, MLE based on lognormal and Weibull distributions provides poor estimates when the true distribution of data is misspecified. However, the methods of rROS, GROS, and MLE under gamma distribution are generally robust to model misspecifications regardless of skewness, sample size, and censoring percentage. Since the characteristics of environmental data (e.g., type of distribution and skewness) are unknown a priori, we suggest using MLE based on gamma distribution, rROS and GROS.

  16. Adjusting to Chronic Health Conditions.

    Science.gov (United States)

    Helgeson, Vicki S; Zajdel, Melissa

    2017-01-03

    Research on adjustment to chronic disease is critical in today's world, in which people are living longer lives, but lives are increasingly likely to be characterized by one or more chronic illnesses. Chronic illnesses may deteriorate, enter remission, or fluctuate, but their defining characteristic is that they persist. In this review, we first examine the effects of chronic disease on one's sense of self. Then we review categories of factors that influence how one adjusts to chronic illness, with particular emphasis on the impact of these factors on functional status and psychosocial adjustment. We begin with contextual factors, including demographic variables such as sex and race, as well as illness dimensions such as stigma and illness identity. We then examine a set of dispositional factors that influence chronic illness adjustment, organizing these into resilience and vulnerability factors. Resilience factors include cognitive adaptation indicators, personality variables, and benefit-finding. Vulnerability factors include a pessimistic attributional style, negative gender-related traits, and rumination. We then turn to social environmental variables, including both supportive and unsupportive interactions. Finally, we review chronic illness adjustment within the context of dyadic coping. We conclude by examining potential interactions among these classes of variables and outlining a set of directions for future research.

  17. 一般形式下斜正态随机向量的矩%Moments of the Skew Normal Random Vectors in the General Case

    Institute of Scientific and Technical Information of China (English)

    方碧琪

    2008-01-01

    In this paper,we derived the moments of the random vectors with the skew normal distributions and their quadratic forms in the general case.As an application,the measures of multivariate skewness and kurtosm are calculated.%本文给出一般形式下斜正态随机向量及其平方型的矩公式.作为应用,计算出了斜正态随机向量的多元偏度和峰度.

  18. MCCB warm adjustment testing concept

    Science.gov (United States)

    Erdei, Z.; Horgos, M.; Grib, A.; Preradović, D. M.; Rodic, V.

    2016-08-01

    This paper presents an experimental investigation in to operating of thermal protection device behavior from an MCCB (Molded Case Circuit Breaker). One of the main functions of the circuit breaker is to assure protection for the circuits where mounted in for possible overloads of the circuit. The tripping mechanism for the overload protection is based on a bimetal movement during a specific time frame. This movement needs to be controlled and as a solution to control this movement we choose the warm adjustment concept. This concept is meant to improve process capability control and final output. The warm adjustment device design will create a unique adjustment of the bimetal position for each individual breaker, determined when the testing current will flow thru a phase which needs to trip in a certain amount of time. This time is predetermined due to scientific calculation for all standard types of amperages and complies with the IEC 60497 standard requirements.

  19. Approximation of skewed interfaces with tensor-based model reduction procedures: Application to the reduced basis hierarchical model reduction approach

    Science.gov (United States)

    Ohlberger, Mario; Smetana, Kathrin

    2016-09-01

    In this article we introduce a procedure, which allows to recover the potentially very good approximation properties of tensor-based model reduction procedures for the solution of partial differential equations in the presence of interfaces or strong gradients in the solution which are skewed with respect to the coordinate axes. The two key ideas are the location of the interface either by solving a lower-dimensional partial differential equation or by using data functions and the subsequent removal of the interface of the solution by choosing the determined interface as the lifting function of the Dirichlet boundary conditions. We demonstrate in numerical experiments for linear elliptic equations and the reduced basis-hierarchical model reduction approach that the proposed procedure locates the interface well and yields a significantly improved convergence behavior even in the case when we only consider an approximation of the interface.

  20. An improved model of induction motors for diagnosis purposes - Slot skewing effect and air-gap eccentricity faults

    Energy Technology Data Exchange (ETDEWEB)

    Ghoggal, A.; Zouzou, S.E.; Sahraoui, M. [Laboratoire de genie electrique de Biskra, Departement d' electrotechnique, Universite Mohamed Khider, BP 145, Biskra (Algeria); Razik, H. [Groupe de Recherche en Electrotechnique et Electronique de Nancy, Universite Henri Poincare, Faculte des Sciences et Techniques, BP 239, F-54506 Vandoeuvre-les-Nancy (France); Khezzar, A. [Laboratoire d' Electrotechnique de Constantine, Universite Mentouri, Constantine (Algeria)

    2009-05-15

    This paper describes an improved method for the modeling of axial and radial eccentricities in induction motors (IM). The model is based on an extension of the modified winding function approach (MWFA) which allows for all harmonics of the magnetomotive force (MMF) to be taken into account. It is shown that a plane view of IM gets easily the motor inductances and reduces considerably the calculation process. The described technique includes accurately the slot skewing effect and leads to pure analytical expressions of the inductances in case of radial eccentricity. In order to model the static, dynamic or mixed axial eccentricity, three suitable alternatives are explained. Unlike the previous proposals, the discussed alternatives take into account all the harmonics of the inverse of air-gap function without any development in Fourier series. Simulation results as well as experimental verifications prove the usefulness and the effectiveness of the proposed model. (author)

  1. High-efficiency photon capturing in ultrathin silicon solar cells with double-sided skewed nanopyramid arrays

    Science.gov (United States)

    Zhang, Shuyuan; Liu, Min; Liu, Wen; Li, Zhaofeng; Liu, Yusheng; Wang, Xiaodong; Yang, Fuhua

    2017-10-01

    Light trapping is essential to improve the performance of thin film solar cells. In this paper, we performed a parametric optimization of double-sided skewed nanopyramid arrays that act as a light trapping scheme to increase light absorption in thin-film c-Si solar cells. Our theoretical optimization reveals that the short-circuit current density in a solar cell, employing only 1 μm silicon could reach as high as 38.57 mA cm‑2, which is 17% and 245% higher than that of the Yablonovitch limit and planar-film counterparts, respectively. Furthermore, we analyzed the underlying physics of the light absorption enhancement through electric field intensity profiles.

  2. Insight into the skew-scattering mechanism of the spin Hall effect: Potential scattering versus spin-orbit scattering

    Science.gov (United States)

    Herschbach, Christian; Fedorov, Dmitry V.; Mertig, Ingrid; Gradhand, Martin; Chadova, Kristina; Ebert, Hubert; Ködderitzsch, Diemo

    2013-11-01

    We present a detailed analysis of the skew-scattering contribution to the spin Hall conductivity using an extended version of the resonant scattering model of Fert and Levy [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.106.157208 106, 157208 (2011)]. For 5d impurities in a Cu host, the proposed phase shift model reproduces the corresponding first-principles calculations. Crucial for that agreement is the consideration of two scattering channels related to p and d impurity states since the discussed mechanism is governed by a subtle interplay between the spin-orbit and potential scattering in both angular-momentum channels. It is shown that the potential scattering strength plays a decisive role for the magnitude of the spin Hall conductivity.

  3. On the effect of intermittency of turbulence on the parabolic relation between skewness and kurtosis in magnetized plasmas

    CERN Document Server

    Guszejnov, Dávid; Zoletnik, Sándor; Lazányi, Nóra

    2014-01-01

    This paper is aimed to contribute to the scientific discussions that have been triggered by the experimental observation of a quadratic relation between the kurtosis and skewness of turbulent fluctuations present in fusion plasmas and other nonlinear physical systems. In this paper we offer a general statistical model which attributes the observed $K = aS^2 + b$ relation to the varying intermittency of the experimental signals. The model is a two random variable model constructed to catch the essential intermittent feature of the real signal. One of the variables is the amplitude of the underlying intermittent event (e.g. turbulent structure) while the other is connected to the intermittency level of the system. This simple model can attribute physical meaning to the $a$ and $b$ coefficients, as they characterize the spatio-temporal statistics of intermittent events. By constructing a particle-conserving Gaussian model for the underlying coherent structures the experimentally measured $a$ and $b$ coefficients...

  4. Tax Adjusted for Imported Equipment

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ Ministry of Finance, Central Administration of Customs, and State Administration of Taxation of P.R. of China jointly issued a "Notice on the Lists Related to the Interim Provisions on the Adjustment of Import Tax Policy on Major Technical Equipment" (the Notice) on April 13rd to adjust the list of equipment catalog and merchandise attached to the "Interim Provisions on the Import Tax Policy on Major Technical Equipment", as well as the preferential scope and extent of the import tax on a number of major technical equipment.

  5. It takes two to tango: reproductive skew and social correlates of male mating success in a lek-breeding bird.

    Science.gov (United States)

    Ryder, Thomas B; Parker, Patricia G; Blake, John G; Loiselle, Bette A

    2009-07-01

    Variance in reproductive success among individuals is a defining characteristic of many social vertebrates. Yet, our understanding of which male attributes contribute to reproductive success is still fragmentary in most cases. Male-male reproductive coalitions, where males jointly display to attract females, are of particular interest to evolutionary biologists because one male appears to forego reproduction to assist the social partner. By examining the relationship between social behaviour and reproductive success, we can elucidate the proximate function of coalitions in the context of mate choice. Here, we use data from a 4-year study of wire-tailed manakins (Pipra filicauda) to provide molecular estimates of reproductive skew and to test the hypothesis that male-male social interactions, in the context of coordinated displays, positively influence a male's reproductive success. More specifically, we quantify male-male social interactions using network metrics and predict that greater connectivity will result in higher relative reproductive success. Our data show that four out of six leks studied had significant reproductive skew, with success apportioned to very few individuals in each lek. Metrics of male social affiliations derived from our network analysis, especially male connectivity, measured as the number of males with whom the focal male has extended interactions, were strong predictors of the number of offspring sired. Thus, network connectivity is associated with male fitness in wire-tailed manakins. This pattern may be the result of shared cues used by both sexes to assess male quality, or the result of strict female choice for coordinated display behaviour.

  6. The effect of baryons on the variance and the skewness of the mass distribution in the Universe at small scales

    Science.gov (United States)

    Guillet, T.; Teyssier, R.; Colombi, S.

    2010-06-01

    We study the dissipative effects of baryon physics on cosmic statistics at small scales using a cosmological simulation of a (50Mpch-1)3 volume of universe. The MareNostrum simulation was performed using the adaptive mesh refinement (AMR) code RAMSES, and includes most of the physical ingredients which are part of the current theory of galaxy formation, such as metal-dependent cooling and UV heating, subgrid modelling of the interstellar medium, star formation and supernova feedback. We reran the same initial conditions for a dark matter only universe, as a reference point for baryon-free cosmic statistics. In this paper, we present the measured small-scale amplification of σ2 and S3 due to baryonic physics and their interpretation in the framework of the halo model. As shown in recent studies, the effect of baryons on the matter power spectrum can be accounted for at scales k physically motivated and depends on two parameters, the mass fraction f d of baryons in the disc and the ratio λd of the disc's characteristic scale to the halo's virial radius. We find this composite profile to reproduce both the small-scale variance and skewness boosts measured in the simulation up to k ~ 102hMpc-1 for physically meaningful values of the parameters f d and λd. Although simulations like the one presented here usually suffer from various problems when compared to observations, our modified halo model could be used as a fitting model to improve the determination of cosmological parameters from weak lensing convergence spectra and skewness measurements.

  7. Integrating Stratification and Information Approaches for Multiple Constrained CAT.

    Science.gov (United States)

    Leung, Chi-Keung; Chang, Hua-Hua; Hau, Kit-Tai

    It is widely believed that item selection methods using the maximum information approach (MI) can maintain high efficiency in trait estimation by repeatedly choosing high discriminating (alpha) items. However, the consequence is that they lead to extremely skewed item exposure distribution in which items with high alpha values becoming overly…

  8. Using Prediction Markets to Track Information Flows: Evidence from Google

    Science.gov (United States)

    Cowgill, Bo; Wolfers, Justin; Zitzewitz, Eric

    Since 2005, Google has conducted the largest corporate experiment with prediction markets we are aware of. In this paper, we illustrate how markets can be used to study how an organization processes information. We show that market participants are not typical of Google’s workforce, and that market participation and success is skewed towards Google’s engineering and quantitatively oriented employees.

  9. Adjustable chain trees for proteins

    DEFF Research Database (Denmark)

    Winter, Pawel; Fonseca, Rasmus

    2012-01-01

    A chain tree is a data structure for changing protein conformations. It enables very fast detection of clashes and free energy potential calculations. A modified version of chain trees that adjust themselves to the changing conformations of folding proteins is introduced. This results in much...

  10. An adjustable contracted CI method

    Institute of Scientific and Technical Information of China (English)

    王育彬; 甘正汀; 苏克和; 文振翼

    1999-01-01

    A new contracted CI scheme——adjustable contracted CI scheme——is presented and programed. The efficiency of this scheme is tested by some example calculations. The result shows that the application of the new scheme is flexible and the correlation energy loss is lower than that of the original externally contracted CI method.

  11. Adjustment or updating of models

    Indian Academy of Sciences (India)

    D J Ewins

    2000-06-01

    In this paper, first a review of the terminology used in the model adjustment or updating is presented. This is followed by an outline of the major updating algorithms cuurently available, together with a discussion of the advantages and disadvantages of each, and the current state-of-the-art of this important application and part of optimum design technology.

  12. Risk-Adjusted Control Charts for Health Care Monitoring

    Directory of Open Access Journals (Sweden)

    Willem Albers

    2011-01-01

    the distribution involved is negative binomial. However, in health care monitoring, (groups of patients will often belong to different risk categories. In the present paper, we will show how information about category membership can be used to adjust the basic negative binomial charts to the actual risk incurred. Attention is also devoted to comparing such conditional charts to their unconditional counterparts. The latter do take possible heterogeneity into account but refrain from risk-adjustment. Note that in the risk adjusted case several parameters are involved, which will all be typically unknown. Hence, the potentially considerable estimation effects of the new charts will be investigated as well.

  13. Cloud Fingerprinting: Using Clock Skews To Determine Co Location Of Virtual Machines

    Science.gov (United States)

    2016-09-01

    cloud: Exploring information leakage in third-party compute clouds,” in Proceedings of the 16th ACM Conference on Computer and Communications Security... ACM , 2009, pp. 199–212. [4] Amazon Virtual Private Cloud: User guide. (2016). Amazon Web Services. [On- line]. Available: http://docs.aws.amazon.com...traffic analysis techniques,” in Proceedings of the 2012 ACM Workshop on Cloud Computing Security Workshop. ACM , 2012, pp. 1–12. [6] A. Herzberg, H

  14. 77 FR 29982 - Federal Acquisition Regulation; Submission for OMB Review; Davis Bacon Act-Price Adjustment...

    Science.gov (United States)

    2012-05-21

    ... Regulation; Submission for OMB Review; Davis Bacon Act-Price Adjustment (Actual Method) AGENCY: Department of... previously approved information collection requirement concerning the Davis-Bacon Act price adjustment... Bacon Act-Price Adjustment (Actual Method), by any of the following methods: Regulations.gov :...

  15. 两跨连续斜交梁桥振动台试验研究%Shaking table tests for a two-span continuous skew girder bridge

    Institute of Scientific and Technical Information of China (English)

    许永吉; 卓卫东; 孙颖

    2016-01-01

    The dynamic characteristics and three-dimensional seismic response of a two-span continuous skew girder bridge were analyzed,using parameters,such as,skew angle,shear span ratio,reinforcement ratio and axial compression ratio and so on.Taking a skewed girder bridge of Fujian as an engineering example,a 1 ∶5 scale two-span continuous skewed girder bridge model was designed for shaking table tests.Adopting shaking table tests and FE numerical analysis, the seismic responses and damage characteristics of the skewed girder bridge were studied.Results of shaking table tests showed that the structure's acceleration response and displacement response are guite different under different types of ground motion and at the same site or different types of ground motion and at different sites;under the same skew angle. the smaller the axial compression ratio,the larger the acceleration and displacement responses;when the axial compression ratio is the same,the smaller the skew angle,the larger the acceleration and displacement responses;a reasonable choice of skew angle has a great influence on the dynamic performance of skew bridges in the design of skew bridges.%选取了斜交角、配箍率和轴压比等设计参数,对两跨连续斜交梁桥进行结构动力特性分析和单向地震动输入下结构的地震反应分析。以福建省高速公路某座斜交梁桥为工程背景,设计制作了一座1/5缩尺两跨连续混凝土斜交梁桥试验模型,结合振动台模型试验和数值模拟分析,研究斜交梁桥地震响应及震害特点。振动台模型试验结果表明:不同场地类别的地震动及同一场地类别但不同的地震动作用下,结构的加速度响应、位移响应差别较大;在相同斜交角时,轴压比越小,加速度和位移响应越大;当轴压比相同时,斜交角越小,加速度和位移响应越大。从试验可知,在斜交桥设计中,合理选择斜交角对桥梁动力性能有很大的影响。

  16. Adjustable wheelchair and method for adjusting said adjustable wheelchair, and wheelchair assembly

    NARCIS (Netherlands)

    Oosterhuis, D.S.

    2013-01-01

    The invention relates to an adjustable wheelchair comprising: -a carriage; -two rear wheels; -at least one front wheel; -at least one footrest; -a sub-frame; -a seat; and -a backrest; wherein the two rear wheels, the at least one front wheel and the at least one footrest are mounted to the carriage,

  17. Measuring the Radial Position of Defects within Optical Fibers Using Skew Rays

    Directory of Open Access Journals (Sweden)

    George Y. Chen

    2017-01-01

    Full Text Available Defects within optical fibers can cause premature failure in fiber-based systems and must be detected early to avoid performance degradation. Addressing this need can ensure that no defective optical fibers are being used by end users and improve processes to reduce the number of defects during manufacturing. The main challenge to date has been developing a technique that can measure defects along long lengths of fiber, within opaque packaging, and with position information. We demonstrate a simple and novel technique for detecting and radially resolving microscopic defects in packaged/buried fibers using an angle-resolved interrogator that analyzes the transmission of different ray groups. We have measured the accuracy to be as low as ±2 μm, which is sufficient for most fibers that have diameters in the order of ~100 μm.

  18. The assessment of social adjustment. A review of techniques.

    Science.gov (United States)

    Weissman, M M

    1975-03-01

    Interest in the community adjustment of psychiatric patients has led to the development of rating techniques for its evaluation. Selection of an appropriate scale for the task should include a review of its item content, anchor points, coverage, method of obtaining information, informant, psychometric properties, precision, cost, scoring, and instructional material. While no scale is without limitations, this report describes 15 currently available scales that meet many of the important criteria for assessing social adjustment and are sufficiently developed to be useful in evaluative research. This review also contains a list of pertinent references to the scales and guide to the literature on behavioral rating scales.

  19. Skewed Riskscapes and Environmental Injustice: A Case Study of Metropolitan St. Louis

    Science.gov (United States)

    Abel, Troy D.

    2008-08-01

    This article presents a case study of Toxics Release Inventory (TRI) air pollution exposure risks across metropolitan St. Louis. The first section critically reviews environmental justice research and related barriers to environmental risk management. Second, the paper offers a conventional analysis of the spatial patterns of TRI facilities and their surrounding census block group demographics for metropolitan St. Louis. Third, the article describes the use of an exposure risk characterization for 319 manufacturers and their air releases of more than 126 toxic pollutants. This information could lead to more practical resolutions of urban environmental injustices. The analysis of TRIs across metropolitan St. Louis shows that minority and low-income residents were disproportionately closer to industrial pollution sources at nonrandom significance levels. Spatial concentrations of minority residents averaged nearly 40% within one kilometer of St. Louis TRI sites compared to 25% elsewhere. However, one-fifth of the region’s air pollution exposure risk over a decade was spatially concentrated among only six facilities on the southwestern border of East St. Louis. This disproportionate concentration of some of the greatest pollution risk would never be considered in most conventional environmental justice analyses. Not all pollution exposure risk is average, and the worst risks deserve more attention from environmental managers assessing and mitigating environmental injustices.

  20. Structural adjustment and the urban informal sector in Nigeria.

    OpenAIRE

    Dawson J; Oyeyinka B

    1993-01-01

    Based on a survey conducted in Lagos and Zaria during 1992 which included 210 interviews in each city with entrepreneurs across seven branches: tailoring, leather-work, wood-work, construction, retailing, metal-work and transport.

  1. The Association between Body Image and Adjustment in Adolescents

    Directory of Open Access Journals (Sweden)

    Mohammadreza Tamannaeifar

    2012-09-01

    Full Text Available Background: Over the past decades a large amount of research has been done on body image of adolescents. The motivation for this new surge is based on its effect on their functions and behaviors. The aim of this study was to investigate relationship between body image and adjustment in both sexes. Materials and Methods: The subjects of the study included 400 male and female students of high school selected by cluster sampling. Information was gathered using Physical Self-Description Questionnaire and Bell Adjustment Inventory. Data were analyzed using Pearson correlation coefficient and stepwise regression analysis.Results: Results indicated that there was significant relationship between body image and adjustment in both sexes.Conclusion: In general, findings demonstrate that positive body image lead to high self worth and adjustive behaviors in both sexes.

  2. A New Automatic Method to Adjust Parameters for Object Recognition

    Directory of Open Access Journals (Sweden)

    Issam Qaffou

    2012-09-01

    Full Text Available To recognize an object in an image, the user must apply a combination of operators, where each operator has a set of parameters. These parameters must be “well” adjusted in order to reach good results. Usually, this adjustment is made manually by the user. In this paper we propose a new method to automate the process of parameter adjustment for an object recognition task. Our method is based on reinforcement learning, we use two types of agents: User Agent that gives the necessary information and Parameter Agent that adjusts the parameters of each operator. Due to the nature of reinforcement learning the results do not depend only on the system characteristics but also the user’s favorite choices.

  3. Skewed distribution of hypothyroidism in the coastal communities of Newfoundland, Canada.

    Science.gov (United States)

    Sarkar, Atanu; Knight, John C; Babichuk, Nicole A; Mulay, Shree

    2015-10-01

    Several studies published in the recent past have shown that rising levels of thyroid disrupting chemicals (TDCs) in the environment affect thyroid function in humans. These TDCs are the anthropogenic organic compounds that enter the human body mostly by ingestion and may trigger autoimmune thyroiditis, the most common cause of hypothyroidism. The studies also show the presence of high levels of TDCs in marine animals; therefore, consumption of contaminated seafood might trigger hypothyroidism. So far, there is no readily available population-based data, showing the regional distribution of hypothyroidism cases. We collected administrative data from the Newfoundland and Labrador Centre for Health Information on hospitalizations with hypothyroidism (from 1998 to 2012) in 41 coastal communities of Newfoundland and found that mean hypothyroidism rates of west and south coasts were significantly higher than in the east coast (1.8 and 1.9 times respectively). A one-way analysis of variance was used to test for regional differences in rates. A significant between-group difference in the rate of hypothyroidism was found (F2,38 = 8.309; p = 0.001). The St. Lawrence River, its estuary and the Gulf of St. Lawrence are heavily polluted with TDCs from industries, their effluents, and urbanization in the Great Lakes Watershed and along the river. Environment Canada has already identified this river along with the Great Lakes Watershed as one of the top TDCs polluted water sources in the country. The west and south coasts are in contact with the Gulf of St. Lawrence. Local marine products are a regular diet of the coastal communities of Newfoundland. Based on these available evidence, we hypothesize the role of TDCs in the rise of hypothyroidism on the western and southern coasts. However, further study will be needed to establish any association between abnormally high rates of hypothyroidism and exposure to TDCs.

  4. Discovery of the Red-Skewed K-alpha Iron Line in Cyg X-2 with Suzaku

    Science.gov (United States)

    Shaposhnikov, Nikolai; Titarchuk, Lev; Laurent, Philippe

    2008-01-01

    We report on the Suzaku observation of neutron star low-mass X-ray binary Cygnus X-2 which reveals strong iron K-alpha emission line. The line profile shows a prominent red wing extending down to 4 keV. This discovery increases the number of neutron star sources where red-skewed iron lines were observed and strongly suggests that this phenomenon is common not only in black holes but also in other types of compact objects. We examine the line profile by fitting it with the model which attributes its production to the relativistic effects due to disk reflection of X-ray radiation. We also apply an alternative model where the red wing is a result of down-scattering effect of the first order with respect to electron velocity in the wind outflow. Both models describe adequately the observed line profile. However, the X-ray variability in a state similar to that in the Suzaku observation which we establish by analysing RXTE observation favors the wind origin of the line formation.

  5. De novo interstitial direct duplication of Xq21.1q25 associated with skewed X-inactivation pattern.

    Science.gov (United States)

    Tachdjian, G; Aboura, A; Benkhalifa, M; Creveaux, I; Foix-Hélias, L; Gadisseux, J F; Boespflug-Tanguy, O; Mohammed, M; Labrune, P

    2004-12-15

    Genotype-phenotype correlation in women with an abnormal phenotype associated with a duplication of the long arm of the X chromosome remains unclear. We report on prenatal diagnosis and follow-up of a girl with an Xq duplication and dysmorphic features. The abnormal phenotype included growth retardation, hypotonia, and nystagmus. In order to improve the resolution of the cytogenetic analysis, we used both conventional and array-based comparative genomic hybridization to perform a global molecular cytogenetic analysis of the genome. These molecular cytogenetic analyses showed a direct duplication Xq21.1 --> q25 without other chromosomal abnormalities. This duplication was originating from the paternal X chromosome. Moreover, a skewed X-inactivation pattern was observed leading to a partial functional disomy of the chromosomal region Xq21.1q25. This report and review of the literature suggest that functional disomy for chromosome X could explain the abnormal phenotype. In prenatal diagnosis, this can have implication for patient management and genetic counseling.

  6. Delayed immune reconstitution after cord blood transplantation is characterized by impaired thymopoiesis and late memory T-cell skewing.

    Science.gov (United States)

    Komanduri, Krishna V; St John, Lisa S; de Lima, Marcos; McMannis, John; Rosinski, Steven; McNiece, Ian; Bryan, Susan G; Kaur, Indreshpal; Martin, Sean; Wieder, Eric D; Worth, Laura; Cooper, Laurence J N; Petropoulos, Demetrios; Molldrem, Jeffrey J; Champlin, Richard E; Shpall, Elizabeth J

    2007-12-15

    Advances in immune assessment, including the development of T-cell receptor excision circle (TREC) assays of thymopoiesis, cytokine-flow cytometry assays of T-cell function, and higher-order phenotyping of T-cell maturation subsets have improved our understanding of T-cell homeostasis. Limited data exist using these methods to characterize immune recovery in adult cord blood (CB) transplant recipients, in whom infection is a leading cause of mortality. We now report the results of a single-center prospective study of T-cell immune recovery after cord blood transplantation (CBT) in a predominantly adult population. Our primary findings include the following: (1) Prolonged T lymphopenia and compensatory expansion of B and natural killer (NK) cells was evident; (2) CB transplant recipients had impaired functional recovery, although we did observe posttransplantation de novo T-cell responses to cytomegalovirus (CMV) in a subset of patients; (3) Thymopoietic failure characterized post-CBT immune reconstitution, in marked contrast to results in other transplant recipients; and (4) Thymopoietic failure was associated with late memory T-cell skewing. Our data suggest that efforts to improve outcomes in adult CB transplant recipients should be aimed at optimizing T-cell immune recovery. Strategies that improve the engraftment of lymphoid precursors, protect the thymus during pretransplant conditioning, and/or augment the recovery of thymopoiesis may improve outcomes after CBT.

  7. HIV-Infected Spleens Present Altered Follicular Helper T Cell (Tfh Subsets and Skewed B Cell Maturation.

    Directory of Open Access Journals (Sweden)

    Lucie Colineau

    Full Text Available Follicular helper T (Tfh cells within secondary lymphoid organs control multiple steps of B cell maturation and antibody (Ab production. HIV-1 infection is associated with an altered B cell differentiation and Tfh isolated from lymph nodes of HIV-infected (HIV+ individuals provide inadequate B cell help in vitro. However, the mechanisms underlying this impairment of Tfh function are not fully defined. Using a unique collection of splenocytes, we compared the frequency, phenotype and transcriptome of Tfh subsets in spleens from HIV negative (HIV- and HIV+ subjects. We observed an increase of CXCR5+PD-1highCD57-Tfh and germinal center (GC CD57+ Tfh in HIV+ spleens. Both subsets showed a reduced mRNA expression of the transcription factor STAT-3, co-stimulatory, regulatory and signal transduction molecules as compared to HIV- spleens. Similarly, Foxp3 expressing follicular regulatory T (Tfr cells were increased, suggesting sustained GC reactions in chronically HIV+ spleens. As a consequence, GC B cell populations were expanded, however, complete maturation into memory B cells was reduced in HIV+ spleens where we evidenced a compromised production of B cell-activating cytokines such as IL-4 and IL-10. Collectively our data indicate that, although Tfh proliferation and GC reactions seem to be ongoing in HIV-infected spleens, Tfh "differentiation" and expression of costimulatory molecules is skewed with a profound effect on B cell maturation.

  8. Hydrodynamic Efficiency Improvement of the High Skew Propeller for the Underwater Vehicle Under Surface and Submerged Conditions

    Institute of Scientific and Technical Information of China (English)

    Hassan Ghassemi; Parviz Ghadimi

    2011-01-01

    An algorithm based on the Boundary Element Method (BEM) is presented for designing the High Skew Propeller (HSP)used in an Underwater Vehicle (UV).Since UVs operate under two different kinds of working conditions (i.e.surface and submerged conditions),the design of such a propeller is an unwieldy task.This is mainly due to the fact that the resistance forces as well as the vessel efficiency under these conditions are significantly different.Therefore,some factors are necessary for the design of the optimum propeller to utilize the power under the mentioned conditions.The design objectives of the optimum propeller are to obtain the highest possible thrust and efficiency with the minimum torque.For the current UV,the main dimensions of the propeller are predicted based on the given required thrust and the defined operating conditions.These dimensions (number of blades,pitch,diameter,expanded area ratio,thickness and camber) are determined through iterative procedure.Because the propeller operates at the stem of the UV where the inflow velocity to the propeller is non-uniform,a 5-blade HSP is preferred for running the UV.Finally,the propeller is designed based on the numerical calculations to acquire the improved hydrodynamic efficiency.

  9. Pharmacologic or Genetic Targeting of Glutamine Synthetase Skews Macrophages toward an M1-like Phenotype and Inhibits Tumor Metastasis

    Directory of Open Access Journals (Sweden)

    Erika M. Palmieri

    2017-08-01

    Full Text Available Glutamine-synthetase (GS, the glutamine-synthesizing enzyme from glutamate, controls important events, including the release of inflammatory mediators, mammalian target of rapamycin (mTOR activation, and autophagy. However, its role in macrophages remains elusive. We report that pharmacologic inhibition of GS skews M2-polarized macrophages toward the M1-like phenotype, characterized by reduced intracellular glutamine and increased succinate with enhanced glucose flux through glycolysis, which could be partly related to HIF1α activation. As a result of these metabolic changes and HIF1α accumulation, GS-inhibited macrophages display an increased capacity to induce T cell recruitment, reduced T cell suppressive potential, and an impaired ability to foster endothelial cell branching or cancer cell motility. Genetic deletion of macrophagic GS in tumor-bearing mice promotes tumor vessel pruning, vascular normalization, accumulation of cytotoxic T cells, and metastasis inhibition. These data identify GS activity as mediator of the proangiogenic, immunosuppressive, and pro-metastatic function of M2-like macrophages and highlight the possibility of targeting this enzyme in the treatment of cancer metastasis.

  10. Next generation sequencing reveals skewing of the T and B cell receptor repertoires in patients with Wiskott Aldrich syndrome

    Directory of Open Access Journals (Sweden)

    Amy E O'Connell

    2014-07-01

    Full Text Available The Wiskott Aldrich syndrome (WAS is due to mutations of the WAS gene encoding for the cytoskeletal WAS protein (WASp, leading to abnormal downstream signaling from the T cell and B cell antigen receptors (TCR, BCR. We hypothesized that the impaired signaling through the TCR and BCR in WAS would subsequently lead to aberrations in the immune repertoire of WAS patients. Using next generation sequencing, the T cell receptor beta (TRB and B cell immunoglobulin heavy chain (IGH repertoires of 8 patients with WAS and 6 controls were sequenced. Clonal expansions were identified within memory CD4+ cells, as well as in total, naïve and memory CD8+ cells from WAS patients. In the B cell compartment, WAS patient IGH repertoires were also clonally expanded and showed skewed usage of IGHV and IGHJ genes, and increased usage of IGHG constant genes, compared with controls. To our knowledge, this is the first study that demonstrates significant abnormalities of the immune repertoire in WAS patients using next generation sequencing.

  11. Next Generation Sequencing Reveals Skewing of the T and B Cell Receptor Repertoires in Patients with Wiskott–Aldrich Syndrome

    Science.gov (United States)

    O’Connell, Amy E.; Volpi, Stefano; Dobbs, Kerry; Fiorini, Claudia; Tsitsikov, Erdyni; de Boer, Helen; Barlan, Isil B.; Despotovic, Jenny M.; Espinosa-Rosales, Francisco J.; Hanson, I. Celine; Kanariou, Maria G.; Martínez-Beckerat, Roxana; Mayorga-Sirera, Alvaro; Mejia-Carvajal, Carmen; Radwan, Nesrine; Weiss, Aaron R.; Pai, Sung-Yun; Lee, Yu Nee; Notarangelo, Luigi D.

    2014-01-01

    The Wiskott–Aldrich syndrome (WAS) is due to mutations of the WAS gene encoding for the cytoskeletal WAS protein, leading to abnormal downstream signaling from the T cell and B cell antigen receptors (TCR and BCR). We hypothesized that the impaired signaling through the TCR and BCR in WAS would subsequently lead to aberrations in the immune repertoire of WAS patients. Using next generation sequencing (NGS), the T cell receptor β and B cell immunoglobulin heavy chain (IGH) repertoires of eight patients with WAS and six controls were sequenced. Clonal expansions were identified within memory CD4+ cells as well as in total, naïve and memory CD8+ cells from WAS patients. In the B cell compartment, WAS patient IGH repertoires were also clonally expanded and showed skewed usage of IGHV and IGHJ genes, and increased usage of IGHG constant genes, compared with controls. To our knowledge, this is the first study that demonstrates significant abnormalities of the immune repertoire in WAS patients using NGS. PMID:25101082

  12. Social Network Dynamics and Psychological Adjustment among University Students

    Directory of Open Access Journals (Sweden)

    Yasuyuki Fukukawa

    2013-04-01

    Full Text Available Abstract The present study investigated the social network structure in a university class and how it changed over time. In addition, student rankings of social status in the class based on different network centrality measures were compared, and associations between students’ social status and psychological adjustment were evaluated. One university seminar class in which ten juniors and ten seniors were enrolled was followed for six months. Although the class network consisted of some disconnected subgroups at baseline, it became a single group at followup. In addition to these structural changes, measures of network integration (density and transitivity also increased from baseline to follow-up. Comparisons of centrality measures indicated that the information centrality measure best captured the network infrastructure compared to the betweenness, closeness, and degree centrality measures. Furthermore, among the centrality measures, information centrality had the most stable positive association with psychological adjustment. Theoretical and practical implications of these peer network dynamics and adjustment issues are discussed.

  13. Conjugate Effect of Joule Heating and Unsteady MHD Natural Convection in a Differentially Heated Skewed Porous Cavity Saturated by Cu-water Nanofluid

    Directory of Open Access Journals (Sweden)

    Omid Ghaffarpasand

    2016-01-01

    Full Text Available Conjugate effect of Joule heating and Lorentz force in a differentially skewed porous lid-driven cavity saturated by Cu-water nanofluid have been examined numerically. A coordinate transformation is utilized to transform the physical domain to the computational domain in an orthogonal coordinate. The Darcy-Brinkman-Forchheimer model with Boussinesq approximation is adopted and the developed mathematical model is solved by finite volume method based on SIMPLE algorithm. The influence of porous medium permeability (Darcy number, Joule heating (Eckert number, nanoparticle volume fraction, as well as inclination angle of skewed cavity on fluid flow and heat transfer characteristics are studied. The entropy generation and Bejan number also evaluated to examine thermodynamic optimization of the MHD mixed convection in porous media. The results have been presented in terms of streamlines, average Nusselt number, entropy generation, and Bejan number for a wide range of key parameters.

  14. Authoritative Parenting and Adolescent Adjustment across Varied Ecological Niches.

    Science.gov (United States)

    Steinberg, Laurence; And Others

    This study examined whether the widely reported positive relation between "authoritative" parenting and adolescent adjustment is moderated by the ecological context in which adolescents live. A socioeconomically and ethnically diverse sample of approximately 10,000 high school students provided information about their parents' behavior…

  15. 75 FR 41434 - Trade Adjustment Assistance for Farmers

    Science.gov (United States)

    2010-07-16

    ... Foreign Agricultural Service Trade Adjustment Assistance for Farmers AGENCY: Foreign Agricultural Service... Crawfish Farmers Association and accepted for review by USDA on May 3, 2010. SUPPLEMENTARY INFORMATION: To... and reviewed by the TAA for Farmers Review Committee, comprised of representatives from USDA's...

  16. Social Class and Belonging: Implications for College Adjustment

    Science.gov (United States)

    Ostrove, Joan M.; Long, Susan M.

    2007-01-01

    This study addressed the extent to which social class position structures a sense of belonging at college, and the ways in which belonging informs adjustment to college. Among 322 liberal arts college students, social class background was significantly associated with a sense of belonging at college and was marginally related to academic…

  17. A price adjustment process in a model of monopolistic competition

    NARCIS (Netherlands)

    J. Tuinstra

    2004-01-01

    We consider a price adjustment process in a model of monopolistic competition. Firms have incomplete information about the demand structure. When they set a price they observe the amount they can sell at that price and they observe the slope of the true demand curve at that price. With this informat

  18. Tokens in the Tower: Perceptual Processes and Interaction Dynamics in Academic Settings with ‘Skewed', ‘Tilted' and ‘Balanced' Sex Ratios

    OpenAIRE

    Hewstone, Miles; Crisp, Richard J.; Contarello, Alberta; Voci, Alberto; Conway, Laura; Marletta, Giorgia; Willis, Hazel

    2006-01-01

    Abstract We tested Kanter?s (1977a, 1977b) theory concerning the effects of group proportions (sex ratios) on visibility, polarization and assimilation, using natural groups of women and men in academia. Study 1 compared male-skewed and male-tilted settings and found evidence of greater polarization by minority women than majority men. The only effect of group proportions occurred for perceived dispersion a...

  19. Measurement of the Skewness of Elliptic Flow Fluctuations in PbPb Collisions at $\\sqrt{s_{NN}} = 5.02~\\mathrm{TeV}$

    CERN Document Server

    CMS Collaboration

    2017-01-01

    Event-by-event flow harmonics are studied for PbPb collisions at $\\sqrt{s_{NN}} = 5.02~\\mathrm{TeV}$ using the CMS detector at the LHC. Flow harmonic probability distributions $p\\left(v_2\\right)$ are obtained using particles of $0.3 \\leq p_{T} \\leq 3.0~\\mathrm{GeV}/c$ and $\\left|\\eta\\right| \\leq 1.0$ and are unfolded to remove smearing effects from observed azimuthal particle distributions. Cumulant flow harmonics are determined from the moments of $p\\left(v_2\\right)$ and used to estimate the standardized elliptic flow skewness in $5\\%$ wide centrality bins up to $60\\%$. Hydrodynamic models predict that flow fluctuations will lead to a non-Gaussian component in the flow distributions with a negative skew with respect to the reaction plane. A significant negative skewness is observed for all centrality bins as evidenced by a splitting between $v_2\\left\\{4\\right\\}$ and $v_2\\left\\{6\\right\\}$ cumulants. In addition, elliptic power law distribution fits are made to the $p\\left(v_2\\right)$ distributions to infer in...

  20. INVESTIGATION OF DYNAMIC PARAMETRS OF SPLIT SKEWED BRIDGE SPANS IN CASE OF LOSS OF CONTACT BETWEEN END BEAM AND ITS SUPPORT

    Directory of Open Access Journals (Sweden)

    V.S.Safronov

    2015-02-01

    Full Text Available Statement of the problem. In order to get a valid estimate of risks of fracture during the mainten-ance of simply supported skew slab-and-girder reinforced concrete spans of highway bridges the influence of the supporting skew on the natural frequencies spectrum and the corresponding ei-genmodes in case of changing the design model due to loss of contact between beams and support.Results. Possible loss of contact between one of the marginal beams and its support near the sharp angle during the maintenance of transport facility depending on its type and geometrical parameters is substantiated. Modal and frequency spectrum analysis of spans in case of loss of contact between one of the marginal beams and its support is performed.Conclusions. The analysis revealed possible loss of contact between marginal beams and support, which increases as the skew angle grows and the width and length of the span reduce. A signifi-cant influence of support separation on eigenmodes and frequency spectrum of spans is revealed.