Bayesian estimation for non zero inflated modified power series distribution under linex and generalized entropy loss functions

Abstract

In this paper, we derive Bayesian estimators of the parameters of modified power series distributions inflated at any of a support point under linex and general entropy loss function. We assume that the prior information can be summarized by a uniform, Beta, two-sided power, Gamma or generalized Pareto distributions. The obtained results are demonstrated on the generalized Poisson and the generalized negative binomial distribution inflated at a given point.     

Probabilistic graph-coloring in bipartite and split graphs

We revisit in this paper the stochastic model for minimum graph-coloring introduced in (Murat and Paschos in Discrete Appl. Math. 154:564–586, 2006), and study the underlying combinatorial optimization problem (called probabilistic coloring) in bipartite and split graphs. We show that the obvious 2-coloring of any connected bipartite graph achieves standard-approximation ratio 2, that when vertex-probabilities are constant probabilistic coloring is polynomial and, finally, we propose a polynomial algorithm achieving standard-approximation ratio 8/7. We also handle the case of split graphs. We show that probabilistic coloring is NP-hard, even under identical vertex-probabilities, that it is approximable by a polynomial time standard-approximation schema but existence of a fully a polynomial time standard-approximation schema is impossible, even for identical vertex-probabilities, unless P=NP. We finally study differential-approximation of probabilistic coloring in both bipartite and split graphs. Part of this research has been performed while the second author was with the LAMSADE on a research position funded by the CNRS.     

The association between triglyceride high density lipoprotein cholesterol ratio and benign prostate hyperplasia in non-diabetic patients:a cross-sectional study

Objectives: To assess the association between triglyceride (TG)/high density lipoprotein (HDL) ratio and benign prostate hyperplasia/lower urinary tract symptoms (BPH/LUTS).

Methods: Four hundred patients who were admitted to the Urology Clinic between January and December 2014 with complaints of BPH/LUTS were enrolled in this cross-sectional study. Patients were divided into two groups according to their International Prostate Symptom Score and prostate volume (PV). They were compared in terms of age, body mass index (BMI), PV, PSA, post micturional residual volume, uroflowmetry Q max value, fasting blood sugar, TG and high density lipoprotein-cholesterol (HDL-C) level and TG/HDL ratio.

Results: Although univariate analyses reveal that age, BMI, waist circumference (WC), FBS, TG, HDL-C level, and TG/HDL ratio were correlated with PV, only age [1.125 OR (1.088–1.164), p?=?.00001], BMI [1.119 OR (1.040–1.204), p?=?.003], TG [(1.043 OR (1.016–1.071), p?=?.002], HDL-C [(0.923 OR (0.860–0.990), p?=?.025], and TG/HDL ratio [(1.224 OR (1.130–1.315), p?=?.014] were statistically significant in multivariate analysis. The calculated area under the curve (AUC) for PV of 30?ml, 40?ml, and 50?ml was 0.668 (0.608–0.727), 0.617 (0.561–0.673), and 0.592 (0.530–0.654), respectively.

Conclusions: Our results indicate that the TG/HDL ratio correlates with enhancement in PV. Further studies are warranted to better evaluate this relationship.     

Self-reported mental health problems and post-traumatic growth among children in Pakistan care homes

ABSTRACT

Children in care experience multiple risk factors, particularly in low-income countries such as Pakistan. The aim was to establish rates of mental health problems and their relationship with posttraumatic growth, as reported by 132 children aged 9–19 years, living in three care homes in Pakistan. Children reported high rates of posttraumatic stress (70.45%) and common mental health symptoms (43.94%) within the clinical range, but also high levels of posttraumatic growth. These findings highlight the high levels of mental health needs among children in residential care, as well as the importance of understanding factors that promote their posttraumatic growth and resilience.     

Metabolomics: opening another window into aging

Metabolomics is based on the simultaneous analysis of multiple low-molecular-weight metabolites from a given sample. As such, metabolomics seeks the most up-to-date information about the state of interaction between an organism and its environment. The ability to use metabolomics approaches for classification and mechanistic studies may influence and augment our ability to study and address the aging process scientifically and clinically.     

Why do Emerging Market Firms Engage in Voluntary Environmental Management Practices? A Strategic Choice Perspective

In this paper, we investigate firms’ decisions to engage in voluntary environmental management (VEM) practices within an emerging market context. Drawing on the strategic choice and the resource‐based view perspectives, we report results from a survey of VEM practices – a specific form of self‐governance – drawing on a sample of 519 Turkish firms from various industries to identify important strategic antecedents of firms’ decisions to engage in such practices. We find that as firms become more customer focused, more inclined to pursue a differentiation strategy and subject to a higher level of strategy‐oriented stakeholder focus, they tend to implement higher levels of VEM practices, with important implications for research, policy and practice for both emerging and developed markets.     

Moment and IV Selection Approaches: A Comparative Simulation Study

We compare three moment selection approaches, followed by post-selection estimation strategies. The first is adaptive least absolute shrinkage and selection operator (ALASSO) of Zou (2006 Zou, H. (2006). The adaptive lasso and its oracle properties. Journal of the American Statistical Association 101:1418–1429.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]), recently extended by Liao (2013 Liao, Z. (2013). Adaptive GMM shrinkage estimation with consistent moment selection. Econometric Theory FirstView:1–48. [Google Scholar]) to possibly invalid moments in GMM. In this method, we select the valid instruments with ALASSO. The second method is based on the J test, as in Andrews and Lu (2001 Andrews, D. W. K., Lu, B. (2001). Consistent model and moment selection procedures for GMM estimation with application to dynamic panel data models. Journal of Econometrics 101(1):123–164.[Crossref], [Web of Science ®] , [Google Scholar]). The third one is using a Continuous Updating Objective (CUE) function. This last approach is based on Hong et al. (2003 Hong, H., Preston, B., Shum, M. (2003). Generalized empirical likelihood based model selection criteria for moment condition models. Econometric Theory 19(06):923–943. [Google Scholar]), who propose a penalized generalized empirical likelihood-based function to pick up valid moments. They use empirical likelihood, and exponential tilting in their simulations. However, the J-test-based approach of Andrews and Lu (2001 Andrews, D. W. K., Lu, B. (2001). Consistent model and moment selection procedures for GMM estimation with application to dynamic panel data models. Journal of Econometrics 101(1):123–164.[Crossref], [Web of Science ®] , [Google Scholar]) provides generally better moment selection results than the empirical likelihood and exponential tilting as can be seen in Hong et al. (2003 Hong, H., Preston, B., Shum, M. (2003). Generalized empirical likelihood based model selection criteria for moment condition models. Econometric Theory 19(06):923–943. [Google Scholar]). In this article, we examine penalized CUE as a third way of selecting valid moments.

Following a determination of valid moments, we run unpenalized generalized method of moments (GMM) and CUE and model averaging technique of Okui (2011 Okui, R. (2011). Instrumental variable estimation in the presence of many moment conditions. Journal of Econometrics 165(1):70–86.[Crossref], [Web of Science ®] , [Google Scholar]) to see which one has better postselection estimator performance for structural parameters. The simulations are aimed at the following questions: Which moment selection criterion can better select the valid ones and eliminate the invalid ones? Given the chosen instruments in the first stage, which strategy delivers the best finite sample performance?

We find that the ALASSO in the model selection stage, coupled with either unpenalized GMM or moment averaging of Okui delivers generally the smallest root mean square error (RMSE) for the second stage coefficient estimators.     

The welfaristic characterization of two-person revelation equilibria under imputational government

Given two players whose declarations about their private preferences are to be used in enforcing imputations, i.e. individually rational Pareto optima according to the declared preference profile, the Nash equilibria of the revelation game so defined always induce individually rational outcomes according to the true preferences, and for all such outcomes there is (and we construct) a Nash equilibrium declaration of preferences which induces precisely that outcome.We conjectured and proved the main result reported here in January, 1989, while M.R. Sertel was visiting at the Decision Sciences and Economics Departments, University of Pennsylvania, and was visited by S. Koray, who was kindly invited by the Wharton School. The hospitality of our hosts is gratefully acknowledged. Participants in the Game Theory course, DS901, in Spring 1989 at the Decision Sciences Department of the Wharton School are thanked hereby for being our first audience, and our special thanks go to Paul Kleindorfer, with whom M.R. Sertel shared the pleasure of giving this course, for his steady encouragement and his persuading us of the importance of our theorem from an experimental viewpoint. TÜBTAK and the Boaziçi University Research Fund. (The Scientific and Technical Research Council of Turkey) partially supported the preparation of this paper, and Bosfor Turizm kindly supported its presentation at the Annual Meeting of ASSET, Florence, Italy, October 1989. We hereby thank a thoughtful anonymous referee for comments which we believe to have led to improvements over an earlier (November 1989) version of this paper.     

Do Parent Units Benefit from Reverse Knowledge Transfer?

Emerging market multinationals resort to knowledge acquisitions from their overseas subsidiaries to springboard and realize their global ambitions. Drawing from the knowledge‐based view and social capital perspective, this study explores the effects of organizational collaboration and tacitness on multiple dimensions of reverse knowledge transfer (RKT). Data were collected through a survey, from senior and middle level managers of parent Indian multinationals, pertaining to RKT from their overseas subsidiaries. The hypotheses are analysed using partial least squares modelling. The results demonstrate positive effects between the extent and benefits of RKT. Collaboration was found to have a positive influence on both dimensions of RKT. Tacitness also has a positive impact on the benefits from RKT. The implications of the findings and the limitations of the study are discussed along with suggestions for future research.     

The disassembly line: balancing and modeling,by S.M. McGovern and S.M. Gupta

This note addresses a problem faced by an actual firm. The problem is to decide on the optimal level of product quality. In performing the economic analysis to determine product quality level, the firm considers revenue, production costs, and research and development costs. However, this note shows that ignoring inventory costs in the analysis will lead to suboptimal product quality levels. Also, including inventory costs in the analysis will lead to reduced production lot sizes. Numerical examples are used to illustrate the results of the model.