On estimating finite mixtures of multivariate regression and simultaneous equation models     

Kamel Jedidi  Venkatram Ramaswamy  Wayne S. DeSarbo  Michel Wedel 《Structural equation modeling》2013,20(3):266-289

We propose a maximum likelihood framework for estimating finite mixtures of multivariate regression and simultaneous equation models with multiple endogenous variables. The proposed “semi‐parametric” approach posits that the sample of endogenous observations arises from a finite mixture of components (or latent‐classes) of unknown proportions with multiple structural relations implied by the specified model for each latent‐class. We devise an Expectation‐Maximization algorithm in a maximum likelihood framework to simultaneously estimate the class proportions, the class‐specific structural parameters, and posterior probabilities of membership of each observation into each latent‐class. The appropriate number of classes can be chosen using various information‐theoretic heuristics. A data set entailing cross‐sectional observations for a diverse sample of businesses is used to illustrate the proposed approach.  相似文献   

Organizational climate and its influence on brokers’ knowledge transfer activities: A structural equation modeling     

Hajer Hammami  Nabil Amara  Réjean Landry 《International Journal of Information Management》2013

The purpose of this paper is to gain a better understanding of the processes involved in transferring knowledge into action. Obviously an interesting subject of research, it is worthwhile delving into the role played by knowledge brokers in bridging the gap between research and practice. This paper investigates the relationship between organizational climate and brokers’ knowledge transfer activities. The structural equation model was tested, using survey data from 301 respondents who primarily carry out their professional activities in health services, such as knowledge brokers. The results suggest two major findings: first, that the organizational climate as a multidimensional concept has a direct positive impact on the brokers’ knowledge transfer activities; secondly, that the organizational climate, characterized by the autonomy granted to brokers and a cooperative climate play an indirect role in affecting the knowledge transfer activities through the mediation of the organizational support provided to brokers.  相似文献   

Real versus spurious correlation     

Mohan Delampady 《Resonance》2013,18(12):1058-1059

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Analysis of protein posttranslational modifications by mass spectrometry: With special reference to haemoglobin     

Murali Woodi  Amit Kumar Mondal  Balaram Padmanabhan  Krishnaswamy Patnam Rajagopalan 《Indian journal of clinical biochemistry : IJCB》2009,24(1):23-29

Mass spectrometry provides a convenient platform for the study of different protein post translational modifications from clinical specimen. Analysis of different post translational modifications of hemoglobin like glycation and glutathionylation can provide useful information on the disease progression and the possible outcome of therapies. In the present study, we have addressed post translational modifications of hemoglobin like glutathionylation and glycation in relation to diabetes and chronic renal failure. We found that both alpha and beta chains of human hemoglobin are glycated irrespective of the extent of glycemia as evidenced by a mass increment of 162 Da. The phenomenon of glutathionylation was observed with only the beta globin chain of hemoglobin probably due to the presence of an accessible cysteine residue indicated by a mass increment of 305 Da. Also, the extent of gltuathionylation observed in the CRF patients could correlate with the severity of the oxidative stress owing to renal replacement therapies like dialysis and transplantation.  相似文献   

The Association Between Small Dense Low Density Lipoprotein and Coronary Artery Disease in North Indian Patients     

Pravin K. Goel  Fauzia Ashfaq  Roopali Khanna  V. Ramesh  Chandra Mohan Pandey 《Indian journal of clinical biochemistry : IJCB》2017,32(2):186-192

Pathogenesis of coronary artery disease (CAD) is multi-factorial and several conventional risk factors have been ascribed; LDL-C being one of the important risk factor. However Indian population studies with established CAD often show LDL levels within normal range in patients with proven CAD. We hypothesized that Small dense low density lipoprotein (sdLDL) being more atherogenic might correlate more strongly to the occurrence and severity of CAD. The aim of the study was to evaluate the association between serum small dense LDL level and angiographically documented coronary artery disease. This is a cross sectional case control study in which sdLDL were measured in 126 patients with CAD and in 64 patients without CAD. Total cholesterol, HDL Cholesterol, LDL cholesterol and triglycerides were measured by standard methods along with other traditional risk factors. Direct quantitative measurement of sdLDL was done by enzymatic analysis. Mean sdLDL level was higher in patients with coronary stenosis than patients without coronary stenosis (16.3 ± 6.8 vs. 10.1 ± 5.7 mg/dL respectively, (p < 0.001). There was significant correlation between mean sdLDL and severity of CAD as assessed by syntax score with mean sdLDL level in low, intermediate and high syntax score being 15.0 ± 5.8, 20.1 ± 6.7 and 22.7 ± 7.3 mg/dL respectively (p value <0.001). A cut off value of 10.02 mg/dL was associated with presence of CAD (95 % CI 0.82–0.93, p < 0.001) using ROC curve. In conclusion Indian patients with established CAD have higher sdLDL levels compared to individuals without CAD despite having comparable LDL levels.  相似文献   

Managing the protection of innovations in knowledge-intensive business services     

Nabil Amara  Réjean Landry  Namatié Traoré 《Research Policy》2008,37(9):1530-1547

How do knowledge-intensive business services (KIBS) protect their inventions from imitation by rival firms when choosing among various protection mechanisms? Data from the 2003 Statistics Canada Innovation Survey on services are used to investigate this issue by looking into complementarities, substitution and independence among eight protection mechanisms. A Multivariate Probit (MVP) model is estimated to take into account the fact that KIBS simultaneously consider many alternative intellectual property (IP) protection methods when they attempt to protect their innovations. Results show that patents, registration of design patterns, trademarks, secrecy and lead-time advantages over competitors constitute legal and informal methods that are used jointly. These complementarities suggest that IP protection mechanisms that are interdependent and reinforce each other to protect innovations from imitation by rival firms constitute a pattern on which firms rely to protect their innovations from imitation. A second pattern is based on the fact that KIBS rely on patents and complexity of designs as substitutes, and tend to use registration of design patterns and complexity of designs as substitutes in protecting their innovations from imitation. A third emerging pattern concerns protection mechanisms that are independent from each other and exhibit no synergy, and do not reinforce each other to protect innovations from imitation by other firms.  相似文献   

The impact of transaction costs on the institutional structuration of collaborative academic research     

Rjean Landry  Nabil Amara 《Research Policy》1998,27(9):901-913

This paper addresses a crucial question: Which factors explain the choices of institutional structures made by university researchers? The main findings of the study point to the central importance of publication assets, coordination costs, additional funding, and membership in the disciplines of engineering, natural sciences and health sciences as factors affecting the choices of institutional structures university researchers make when they become involved in collaborative research projects. On the other hand, the number of years researchers have been involved in collaborative research, the capture of additional publications linked to involvement in collaborative research, the importance of administrative burdens and the time required to coordinate collaborative research were demonstrated to be unimportant in explaining these choices.  相似文献   

Effect of short term vitamin E supplementation on lipid peroxidation in acute myocardial infarction     

A. P. Jain  A. Mohan  O. P. Gupta  U. N. Jajoo  S. P. Kalantri  L. M. Srivastava 《Indian journal of clinical biochemistry : IJCB》1998,13(2):119-122

In view of sufficient body of evidence to substantiate the role of free radical mediated oxidative injury in myocardial infarction (M.I.), the utility of exogenous supplementation with antioxidant substance, vitamin E was studied. Forty patients of acute myocardial infarction were divided into two equal groups, one who received vitamin E and the other who did not. Plasma MDA levels showed a reduction in patients of M.I. who received vitamin E as well as in those who did not, however, the decrease was significantly more in the vitamin E treated subgroup.  相似文献   

阅读疗法——高校图书馆信息服务新拓展   总被引：3，自引：0，他引：3  

杨丽兵  孟默涵 《现代情报》2010,30(3):109-112

从阅读疗法的概念入手,分析了高校图书馆开展阅读疗法的可行性,给出了高校图书馆开展阅读疗法的具体步骤,并强调了高校图书馆开展阅读疗法应注意的事项。  相似文献   

Bayesian statistics     

Mohan Delampady  T. Krishnan 《Resonance》2002,7(4):27-38

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