The exponentiated generalized inverse Gaussian distribution

The modeling and analysis of lifetime data is an important aspect of statistical work in a wide variety of scientific and technological fields. Good (1953) introduced a probability distribution which is commonly used in the analysis of lifetime data. For the first time, based on this distribution, we propose the so-called exponentiated generalized inverse Gaussian distribution, which extends the exponentiated standard gamma distribution (Nadarajah and Kotz, 2006). Various structural properties of the new distribution are derived, including expansions for its moments, moment generating function, moments of the order statistics, and so forth. We discuss maximum likelihood estimation of the model parameters. The usefulness of the new model is illustrated by means of a real data set. (c) 2010 Elsevier B.V. All rights reserved.

The influence of ARIMA-GARCH parameters in feed forward neural networks prediction

The objective of this article is to find out the influence of the parameters of the ARIMA-GARCH models in the prediction of artificial neural networks (ANN) of the feed forward type, trained with the Levenberg-Marquardt algorithm, through Monte Carlo simulations. The paper presents a study of the relationship between ANN performance and ARIMA-GARCH model parameters, i.e. the fact that depending on the stationarity and other parameters of the time series, the ANN structure should be selected differently. Neural networks have been widely used to predict time series and their capacity for dealing with non-linearities is a normally outstanding advantage. However, the values of the parameters of the models of generalized autoregressive conditional heteroscedasticity have an influence on ANN prediction performance. The combination of the values of the GARCH parameters with the ARIMA autoregressive terms also implies in ANN performance variation. Combining the parameters of the ARIMA-GARCH models and changing the ANN`s topologies, we used the Theil inequality coefficient to measure the prediction of the feed forward ANN.

Bayesian Analysis for the Generalized Lognormal Distribution Applied to Failure Time Analysis

There are several versions of the lognormal distribution in the statistical literature, one is based in the exponential transformation of generalized normal distribution (GN). This paper presents the Bayesian analysis for the generalized lognormal distribution (logGN) considering independent non-informative Jeffreys distributions for the parameters as well as the procedure for implementing the Gibbs sampler to obtain the posterior distributions of parameters. The results are used to analyze failure time models with right-censored and uncensored data. The proposed method is illustrated using actual failure time data of computers.

Local power of some tests in exponential family nonlinear models

In this paper we obtain asymptotic expansions up to order n(-1/2) for the nonnull distribution functions of the likelihood ratio, Wald, score and gradient test statistics in exponential family nonlinear models (Cordeiro and Paula, 1989), under a sequence of Pitman alternatives. The asymptotic distributions of all four statistics are obtained for testing a subset of regression parameters and for testing the dispersion parameter, thus generalising the results given in Cordeiro et al. (1994) and Ferrari et al. (1997). We also present Monte Carlo simulations in order to compare the finite-sample performance of these tests. (C) 2010 Elsevier B.V. All rights reserved.

The mitochondrial transcription factor A functions in mitochondrial base excision repair

Mitochondrial transcription factor A (TFAM) is an essential component of mitochondrial nucleoids TFAM plays an important role in mitochondrial transcription and replication TFAM has been previously reported to inhibit nucleotide excision repair (NER) in vitro but NER has not yet been detected in mitochondria, whereas base excision repair (BER) has been comprehensively characterized in these organelles The BER proteins are associated with the inner membrane in mitochondria and thus with the mitochondrial nucleoid, where TFAM is also situated However, a function for TFAM in BER has not yet been investigated This study examines the role of TFAM in BER In vitro studies with purified recombinant TFAM indicate that it preferentially binds to DNA containing 8-oxoguanines, but not to abasic sites, uracils, or a gap in the sequence TFAM inhibited the in vitro incision activity of 8-oxoguanine DNA glycosylase (OGG1), uracil-DNA glycosylase (UDG), apurinic endonuclease 1 (APE1), and nucleotide incorporation by DNA polymerase gamma (pol gamma) On the other hand, a DNA binding-defective TFAM mutant, L58A, showed less inhibition of BER in vitro Characterization of TFAM knockdown (KD) cells revealed that these lysates had higher 8oxoG incision activity without changes in alpha OGG1 protein levels TFAM KD cells had mild resistance to menadione and increased damage accumulation in the mtDNA when compared to the control cells In addition, we found that the tumor suppressor p53, which has been shown to interact with and alter the DNA binding activity of TFAM, alleviates TFAM-Induced inhibition of BER proteins Together, the results suggest that TFAM modulates BER in mitochondria by virtue of its DNA binding activity and protein interactions Published by Elsevier B V

Detecting Major Genes Controlling Robustness of Chicken Body Weight Using Double Generalized Linear Models

Detecting both the majors genes that control the phenotypic mean and those controlling phenotypic variance has been raised in quantitative trait loci analysis. In order to mapping both kinds of genes, we applied the idea of the classic Haley-Knott regression to double generalized linear models. We performed both kinds of quantitative trait loci detection for a Red Jungle Fowl x White Leghorn F2 intercross using double generalized linear models. It is shown that double generalized linear model is a proper and efficient approach for localizing variance-controlling genes. We compared two models with or without fixed sex effect and prefer including the sex effect in order to reduce the residual variances. We found that different genes might take effect on the body weight at different time as the chicken grows.

The functions of intermediaries in Swedish SMEs internationalization to the Nigerian market

Over the years so many academic literatures has revealed that increased number of firms have seen internationalization as a means to gain and sustain competitive advantage and even increase economic of scale, and this has led many western companies to emerging markets. In this paper we discovered that among the pool of Swedish firms, only the MNEs have seen Nigerian market attractive to internationalize to, but just a few of the Swedish SMEs has expanded to the Nigerian market. This research was conducted by doing a qualitative study with the use of phenomenological research approach, during our investigation on the functions of intermediaries in Swedish SMEs internationalization to Nigeria market.Furthermore, we were able to understand the importance and functions of the different marketing intermediaries’ in Swedish SMEs internationalization to Nigeria market. These intermediaries equip the Swedish firms with the required objective knowledge of the Nigerian market, updating them with recent development of the opportunities and threats involved in the Nigerian marketing environment, and linking these Swedish firms to the required government departments, distributors, agent/broker, customers, middle men etc, thereby impacting them with the experiential knowledge. Moreover, it is important for firms to have objective or pre-market knowledge of a particular market before entering that market, but this knowledge is regarded as non-helpful knowledge to firms. But the experiential knowledge is acquired over time in the market, which is regarded as the helpful knowledge. It is evident that the intermediaries equip these firms with both objective and experiential knowledge.Although the opportunities in some emerging markets are very attractive, but the threats in these markets are other factors firms also put into consideration before internationalizing to these markets. This is why thorough market research has to be done so that firms can create effective marketing strategies when they want to expand their marketing activities to emerging markets. Despite the risk and uncertainties involved in doing business in foreign countries, still yet companies selling global products do not have any choice than to internationalize their marketing operations.

The functions of Japanese Sound Symbolic Words in Different Types of Texts and Their Translation

Though sound symbolic words (onomatopoeia and mimetic words, or giongo and gitaigo in Japanese) exist in other languages, it would not be so easy to compare them to those in Japanese. This is because unlike in Japanese, in many other languages (here we see English and Spanish) sound symbolic words do not have distinctive forms that separate them immediately from the rest of categories of words. In Japanese, a sound symbolic word has a radical (that is based on the elaborated Japanese sound symbolic system), and often a suffix that shows subtle nuance. Together they give the word a distinctive form that differentiates it from other categories of words, though its grammatical functions could vary, especially in the case of mimetic words (gitaigo). Without such an obvious feature, in other languages, it would not be always easy to separate sound symbolic words from the rest. These expressions are extremely common and used in almost all types of text in Japanese, but their elaborated sound symbolic system and possibly their various grammatical functions are making giongo and gitaigo one of the most difficult challenges for the foreign students and translators. Studying the translation of these expressions into other languages might give some indication related to the comparison of Japanese sound symbolic words and those in other languages. Though sound symbolic words are present in many types of texts in Japanese, their functions in traditional forms of text (letters only) and manga (Japanese comics)are different and they should be treated separately. For example, in traditional types of text such as novels, the vast majority of the sound symbolic words used are mimetic words (gitaigo) and most of them are used as adverbs, whereas in manga, the majority of the sound symbolic words used (excluding those appear within the speech bubbles) are onomatopoeias (giongo) and often used on their own (i.e. not as a part of a sentence). Naturally, the techniques used to translate these expressions in the above two types of documents differ greatly. The presentation will focus on i) grammatical functions of Japanese sound symbolic words in traditional types of texts (novels/poems) and in manga works, and ii) whether their features and functions are maintained (i.e. whether they are translated as sound symbolic words) when translated into other languages (English and Spanish). The latter point should be related to a comparison of sound symbolic words in Japanese and other languages, which will be also discussed.

Game Audio in Audio Games : Towards a Theory on the Roles and Functions of Sound in Audio Games

For the past few decades, researchers have increased our understanding of how sound functions within various audio–visual media formats. With a different focus in mind, this study aims to identify the roles and functions of sound in relation to the game form Audio Games, in order to explore the potential of sound when acting as an autonomous narrative form. Because this is still a relatively unexplored research field, the main purpose of this study is to help establish a theoretical ground and stimulate further research within the field of audio games. By adopting an interdisciplinary approach to the topic, this research relies on theoretical studies, examinations of audio games and contact with the audio game community. In order to reveal the roles of sound, the gathered data is analyzed according to both a contextual and a functional perspective. The research shows that a distinction between the terms ‘function’ and ‘role’ is important when analyzing sound in digital games. The analysis therefore results in the identification of two analytical levels that help define the functions and roles of an entity within a social context, named the Functional and the Interfunctional levels. In addition to successfully identifying three main roles of sound within audio games—each describing the relationship between sound and the entities game system, player and virtual environment—many other issues are also addressed. Consequently, and in accordance with its purpose, this study provides a broad foundation for further research of sound in both audio games and video games.

Feasible estimation of generalized linear mixed models (GLMM) with weak dependency between groups

This paper presents a two-step pseudo likelihood estimation technique for generalized linear mixed models with the random effects being correlated between groups. The core idea is to deal with the intractable integrals in the likelihood function by multivariate Taylor's approximation. The accuracy of the estimation technique is assessed in a Monte-Carlo study. An application of it with a binary response variable is presented using a real data set on credit defaults from two Swedish banks. Thanks to the use of two-step estimation technique, the proposed algorithm outperforms conventional pseudo likelihood algorithms in terms of computational time.

Estimation of genetic variance for macro- and micro-environmental sensitivity using double hierarchical generalized linear models

Background: Genetic variation for environmental sensitivity indicates that animals are genetically different in their response to environmental factors. Environmental factors are either identifiable (e.g. temperature) and called macro-environmental or unknown and called micro-environmental. The objectives of this study were to develop a statistical method to estimate genetic parameters for macro- and micro-environmental sensitivities simultaneously, to investigate bias and precision of resulting estimates of genetic parameters and to develop and evaluate use of Akaike’s information criterion using h-likelihood to select the best fitting model. Methods: We assumed that genetic variation in macro- and micro-environmental sensitivities is expressed as genetic variance in the slope of a linear reaction norm and environmental variance, respectively. A reaction norm model to estimate genetic variance for macro-environmental sensitivity was combined with a structural model for residual variance to estimate genetic variance for micro-environmental sensitivity using a double hierarchical generalized linear model in ASReml. Akaike’s information criterion was constructed as model selection criterion using approximated h-likelihood. Populations of sires with large half-sib offspring groups were simulated to investigate bias and precision of estimated genetic parameters. Results: Designs with 100 sires, each with at least 100 offspring, are required to have standard deviations of estimated variances lower than 50% of the true value. When the number of offspring increased, standard deviations of estimates across replicates decreased substantially, especially for genetic variances of macro- and micro-environmental sensitivities. Standard deviations of estimated genetic correlations across replicates were quite large (between 0.1 and 0.4), especially when sires had few offspring. Practically, no bias was observed for estimates of any of the parameters. Using Akaike’s information criterion the true genetic model was selected as the best statistical model in at least 90% of 100 replicates when the number of offspring per sire was 100. Application of the model to lactation milk yield in dairy cattle showed that genetic variance for micro- and macro-environmental sensitivities existed. Conclusion: The algorithm and model selection criterion presented here can contribute to better understand genetic control of macro- and micro-environmental sensitivities. Designs or datasets should have at least 100 sires each with 100 offspring.