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Background: This paper summarizes the results of a group effort to bring together the worldwide available data on patients who are either homozygotes or compound heterozygotes for mutations in MAT1A. MAT1A encodes the subunit that forms two methionine adenosyltransferase isoenzymes, tetrameric MAT I and dimeric MAT III, that catalyze the conversion of methionine and ATP to S-adenosylmethionine (AdoMet). Subnormal MAT I/III activity leads to hypermethioninemia. Individuals, with hypermethioninemia due to one of the MAT1A mutations that in heterozygotes cause relatively mild and clinically benign hypermethioninemia are currently often being flagged in screening programs measuring methionine elevation to identify newborns with defective cystathionine β-synthase activity. Homozygotes or compound heterozygotes for MAT1A mutations are less frequent. Some but not all, such individuals have manifested demyelination or other CNS abnormalities. Purpose of the study: The goals of the present effort have been to determine the frequency of such abnormalities, to find how best to predict whether they will occur, and to evaluate the outcomes of the variety of treatment regimens that have been used. Data have been gathered for 64 patients, of whom 32 have some evidence of CNS abnormalities (based mainly on MRI findings), and 32 do not have such evidence. Results and Discussion: The results show that mean plasma methionine concentrations provide the best indication of the group into which a given patient will fall: those with means of 800 μM or higher usually have evidence of CNS abnormalities, whereas those with lower means usually do not. Data are reported for individual patients for MAT1A genotypes, plasma methionine, total homocysteine (tHcy), and AdoMet concentrations, liver function studies, results of 15 pregnancies, and the outcomes of dietary methionine restriction and/or AdoMet supplementation. Possible pathophysiological mechanisms that might contribute to CNS damage are discussed, and tentative suggestions are put forth as to optimal management. © 2015 Chien et al.

The authors examine antecedents of consumer innovativeness in a cross-national context. They propose a framework that distinguishes individual difference variables and national cultural variables. Two types of individual difference variables are considered: personal values and consumer-context-specific dispositions. The authors develop hypotheses pertaining to the main effects of the variables and their interactions and test them on data collected from 3283 consumers in 11 countries of the European Union. The empirical results are broadly supportive of the hypotheses. The cross-national data used in this study provide a strong test of the generalizability of the findings.

The authors propose a general model that includes the effects of discrete and continuous heterogeneity as well as self-stated and derived attribute importance in hybrid conjoint studies. Rather than use the self-stated importances as prior information, as has been done in several previous approaches, the authors consider them data and therefore include them in the formulation of the likelihood, which helps investigate the relationship of self-stated and derived importances at the individual level. The authors formulate several special cases of the model and estimate them using the Gibbs sampler. The authors reanalyze Srinivasan and Park's (1997) data and show that the current model predicts real choices better than competing models do. The posterior credible intervals of the predictions of models with the different heterogeneity specifications overlap, so there is no clear superior specification of heterogeneity. However, when different sources of data are used-that is, full profile evaluations, self-stated importances, or both-clear differences arise in the accuracy of predictions. Moreover, the authors find that including the self-stated importances in the likelihood leads to much better predictions than does considering them prior information.

With increasing competition in the global marketplace, international segmentation has become an ever more important issue in developing, positioning, and selling products across national borders. The authors propose a methodology to identify cross-national market segments, based on means-end chain theory. The methodology offers the potential for integrating product development and communication strategies by linking product characteristics to consumer benefits and values. For that purpose, a model is developed that identifies relations between the consumer and the product at the segment level, which increases the actionability and responsiveness of the segments. The model accounts for different response tendencies, across and within countries, that commonly hamper identification of cross-national segments. A Monte Carlo study shows that the model performs well in recovering the parameters across a wide range of conditions, The segmentation model is applied to consumer data on yogurt collected in 11 countries of the European Union. Four international segments are identified and found to be related to consumer sociodemographics, consumption patterns, media consumption, and personality, The authors show that the model has high predictive validity and outperforms the standard clustering approaches traditionally employed in international segmentation.

The authors examine antecedents of consumer innovativeness in a cross-national context. They propose a framework that distinguishes individual difference variables and national cultural variables. Two types of individual difference variables are considered: personal values and consumer-context-specific dispositions. The authors develop hypotheses pertaining to the main effects of the variables and their interactions and test them on data collected from 3283 consumers in 11 countries of the European Union. The empirical results are broadly supportive of the hypotheses. The cross-national data used in this study provide a strong test of the generalizability of the findings.

Means-end chain theory links products to consumers by postulating hierarchical relations between attributes of the product, consequences of product use and values of consumers. It has served as an important conceptual framework for studies in marketing. The authors investigate the association pattern technique (APT) as a supplement to laddering, the most popular, qualitative measurement methodology in means-end chains research. APT is a structured method for measuring means-end chains, suitable for large-scale surveys. It can be used in personal as well as quantitative mail interviews. APT separately measures the attribute-consequence, and the consequence-value links. The independence of attribute-consequence, and consequence-value links is crucial to the validity of APT. Using loglinear models, we investigate this assumption for empirical data on four different products. Consistent support for independence is found. In addition, we use loglinear models to test the convergent validity of APT and laddering with respect to the content and structure of the means-end chains network that they reveal. The results show that the content of the APT and laddering networks differs. This result is explained from the different task formats. Most importantly, the hypothesis that the structure of APT and laddering networks is the same could not be rejected. (C) 1998 Elsevier Science B.V.

This paper investigates asymmetric effects of monetary policy over the business cycle. A two-state Markov Switching Model is employed to model both recessions and expansions. For the United States and Germany, strong evidence is found that monetary policy is more effective in a recession than during a boom. Also some evidence is found for asymmetry in the United Kingdom and Belgium. In the Netherlands, monetary policy is not very effective in either regime.

This paper introduces a general, formal treatment of dynamic constraints, i.e., constraints on the state changes that are allowed in a given state space. Such dynamic constraints can be seen as representations of "real world" constraints in a managerial context. The notions of transition, reversible and irreversible transition, and transition relation will be introduced. The link with Kripke models (for modal logics) is also made explicit. Several (subtle) examples of dynamic constraints will be given. Some important classes of dynamic constraints in a database context will be identified, e.g. various forms of cumulativity, non-decreasing values, constraints on initial and final values, life cycles, changing life cycles, and transition and constant dependencies. Several properties of these dependencies will be treated. For instance, it turns out that functional dependencies can be considered as "degenerated" transition dependencies. Also, the distinction between primary keys and alternate keys is reexamined, from a dynamic point of view.