A simple method to visualize results in nonlinear regression models

A simple graphical approach to presenting results from nonlinear regression models is described. In the face of multiple covariates, ‘partial mean’ plots may be unattractive. The approach here is portable to a variety of settings and can be tailored to the specific application at hand. A simple four variable nonparametric regression example is provided to illustrate the technique. ► Visualizing estimates from nonlinear models is difficult. ► Propose simple graphical technique to visualize estimates. ► Method had a wide array of application domains. ► Method does not require fixing covariates at a given value

Differencing techniques in semi-parametric panel data varying coefficient models with fixed effects: a Monte Carlo study.

Recently, some new techniques have been proposed for the estimation of semi-parametric fixed effects varying coefficient panel data models. These new techniques fall within the class of the so-called differencing estimators. In particular, we consider first-differences and within local linear regression estimators. Analyzing their asymptotic properties it turns out that, keeping the same order of magnitude for the bias term, these estimators exhibit different asymptotic bounds for the variance. In both cases, the consequences are suboptimal non-parametric rates of convergence. In order to solve this problem, by exploiting the additive structure of this model, a one-step backfitting algorithm is proposed. Under fairly general conditions, it turns out that the resulting estimators show optimal rates of convergence and exhibit the oracle efficiency property. Since both estimators are asymptotically equivalent, it is of interest to analyze their behavior in small sample sizes. In a fully parametric context, it is well-known that, under strict exogeneity assumptions the performance of both first-differences and within estimators is going to depend on the stochastic structure of the idiosyncratic random errors. However, in the non-parametric setting, apart from the previous issues other factors such as dimensionality or sample size are of great interest. In particular, we would be interested in learning about their relative average mean square error under different scenarios. The simulation results basically confirm the theoretical findings for both local linear regression and one-step backfitting estimators. However, we have found out that within estimators are rather sensitive to the size of number of time observations

Identification and Typing of Human Enterovirus: A Genomic Barcode Approach

Identification and typing of human enterovirus (HEVs) are important to pathogen detection and therapy. Previous phylogeny-based typing methods are mainly based on multiple sequence alignments of specific genes in the HEVs, but the results are not stable with respect to different choices of genes. Here we report a novel method for identification and typing of HEVs based on information derived from their whole genomes. Specifically, we calculate the k-mer based barcode image for each genome, HEV or other human viruses, for a fixed k, 1<k<7, where a genome barcode is defined in terms of the k-mer frequency distribution across the whole genome for all combinations of k-mers. A phylogenetic tree is constructed using a barcode-based distance and a neighbor-joining method among a set of 443 representative non-HEV human viruses and 395 HEV sequences. The tree shows a clear separation of the HEV viruses from all the non-HEV viruses with 100% accuracy and a separation of the HEVs into four distinct clads with 93.4% consistency with a multiple sequence alignment-based phylogeny. Our detailed analyses of the HEVs having different typing results by the two methods indicate that our results are in better agreement with known information about the HEVs

Foreign direct investment and economic integration

In this paper, we explore the role of foreign direct investment (FDI) on the competitiveness of emerging economies and economic integration. We structure the paper as follows. Following this Introduction (Section I), in Section II, we assess briefly and critically extant theories of FDI and the MNE. In Section III, we critically assess competitiveness and catching-up theory and policy and the role of FDI in this context. Section IV sets off from limitations of extant scholarship identified in the previous section to develop a novel framework for competitiveness and catching-up and discuss the role of FDI, clusters and government policy in its context. Section V discusses ways through which emerging economies can effect economic integration through enhanced competitiveness and accelerated catching-up, by leveraging strategies informed from recent developments on scholarship in International Business (IB) strategy. Section VI summarizes and concludes

Determinants of MNE Subsidiaries Decision to Set up Own R&D Laboratories: The Choice of Region

We test for the determinants of Multinational Enterprise (MNE) headquarters decisions to augment the innovative capabilities of the MNE group by granting mandates to their subsidiaries to set-up own R&D labs in UK regions, using a unique primary data set.Our findings suggest that the best predictor for a subsidiary receiving a mandate, is the strength of its `productive opportunity (the interaction between internal competencies and external environment). We employ a measure that augments the external environment to include regional agglomeration characteristics.Our findings highlight the importance of subsidiary, industry and locational characteristics, as well asMNE strategy to leverage subsidiary skills in determining the location of R&D activity in the global economy and in enhancing MNE innovative potential

Amplification of Echoviruses genomic regions by different RT-PCR protocols - a comparative study

In the present report, the results of a comparative study in the detection of all Echoviruses reference strains as well as of 38 clinical isolates are presented. Using RT-PCR with already published primer pairs (UG(52)-UC53, 292-222, 012-011 and EUG2a, 2b, 2c-EUC2) from the 5’UTR, the VP1 region as well as a long genomic fragment including the VP1 3’ end, the entire coding sequence of 2A, 2B, and the 5’ moiety of the 2C-coding region amplification was effective with all reference and clinical Echovirus isolates with primer pair UG52-UC53 while with 292-222 and 012-011 were amplified 27/28 reference Echovirus strains and all clinical isolates. As far as EUG2a,2b,2c-EUC2 is concerned, the RT-PCR gave a positive result for 26/28 reference Echovirus strains and 34/38 clinical isolates. The sequence analysis of a large part of the 5’UTR has revealed that there is no correlation between 5’UTR identity and the currently recognized human enterovirus species. It has been suggested that part of VP1 coding sequence would correlate well with serotype since a number of important neutralization epitopes, as well as receptor recognition sequences, lie within the VP1 coding sequence. Therefore, UG52-UC53 and 292-222 primer pairs seem to be the most appropriate for Echovirus detection and, moreover, UG52-UC53 is useful for the classification of enteroviruses into genetic clusters (sub-groups) while 292-222 for the identification of enteroviruses by amplicon sequencing. (C) 2004 Elsevier Ltd. All rights reserved

The epidemiology of sheep pox in Greece from 1987 to 2007

The authors review the epidemiology of sheep pox outbreaks in Greece between 1987 and 2007. It is believed that sheep pox is introduced into Greece principally from neighbouring countries to the east, and is associated with the movements of infected sheep flocks close to the border and contacts between humans and animals. Disease foci have appeared in several central and north-eastern areas of the country. Between 1982 and 1986, Greece remained free of sheep pox but, in 1987, the disease appeared on the island of Lesvos and, in 1988, outbreaks were seen in the prefecture of Evros. In 1994, a further outbreak occurred in Evros. Over the next four years, more outbreaks occurred in Evros and Thessaloniki (1995); Larissa, Xanthi, Rhodopi, Kavala, Magnissia, Evros and the island of Lesvos (1996); Kavala, Magnissia, Halkidiki, Evros and Rhodopi (1997). In 1998, there were fewer cases of sheep pox, with outbreaks only in the prefecture of Evros. Two years later, a further outbreak was reported in Evros (2000), while the most recent outbreak occurred on the island of Lesvos in January 2007

Amplification of Echoviruses genomic regions by different RT-PCR protocols - a comparative study

In the present report, the results of a comparative study in the detection of all Echoviruses reference strains as well as of 38 clinical isolates are presented. Using RT-PCR with already published primer pairs (UG(52)-UC53, 292-222, 012-011 and EUG2a, 2b, 2c-EUC2) from the 5'UTR, the VP1 region as well as a long genomic fragment including the VP1 3' end, the entire coding sequence of 2A, 2B, and the 5' moiety of the 2C-coding region amplification was effective with all reference and clinical Echovirus isolates with primer pair UG52-UC53 while with 292-222 and 012-011 were amplified 27/28 reference Echovirus strains and all clinical isolates. As far as EUG2a,2b,2c-EUC2 is concerned, the RT-PCR gave a positive result for 26/28 reference Echovirus strains and 34/38 clinical isolates. The sequence analysis of a large part of the 5'UTR has revealed that there is no correlation between 5'UTR identity and the currently recognized human enterovirus species. It has been suggested that part of VP1 coding sequence would correlate well with serotype since a number of important neutralization epitopes, as well as receptor recognition sequences, lie within the VP1 coding sequence. Therefore, UG52-UC53 and 292-222 primer pairs seem to be the most appropriate for Echovirus detection and, moreover, UG52-UC53 is useful for the classification of enteroviruses into genetic clusters (sub-groups) while 292-222 for the identification of enteroviruses by amplicon sequencing. (C) 2004 Elsevier Ltd. All rights reserved