Brain amino acid abnormalities in liver disease--a postmortem study

In a postmortem exploratory study, we examined whether specific amino acid abnormalities associated with liver diseases in vivo may also be detected in human brain samples obtained at clinical autopsies. The branched-chain amino acids (BCAA: valine, leucine, isoleucine) were decreased in the group of patients with liver diseases compared with the control group, whereas the aromatic amino acids (AAA: phenylalanine, tyrosine) were increased. However, the ranges overlapped significantly and were not statistically different. The molar ratio BCAA/AAA was determined to be 1.92 in the collection of patients with liver diseases compared with 2.27 in the control group. In patients with liver disease, ornithine concentrations in the brain appeared significantly decreased whereas glutamine was significantly increased. No significant difference was found in the brain concentrations of proline. Amino acid analysis may contribute to the understanding of pathophysiological mechanisms of liver disease, which are discussed, and may supplement the postmortem diagnosis.     

Sense and sensitivity in pooled analysis of political data

Abstract. In recent years, pooled time–series cross–section data analysis has been advocated as a method for overcoming the 'small N, many variables' problem in comparative political economy in order to derive valid inferences from statistical comparisons of nation states. Moreover, the approach seemed promising in handling both comparisons among different countries and developments over time. However, due to the complex structure of pooled data sets, this approach cannot simply be regarded as a convenient way of increasing the number of cases and getting more significant results. This paper exemplifies the fallacies of pooled data sets by reanalyzing a study done by Paul Boreham and Hugh Compston on the effect of labour participation in policy formation on unemployment. Reanalysis of their data set controlling for the panel structure of the data by using 'panel corrected standard errors' and a more detailed analysis of the bivariate relationships show that the causal effect is less clear–cut than suggested and becomes considerably weaker during the 1980s. These dynamics are simply averaged out by pooled analysis. This leads to the conclusion that the currently most popular approach to pooled time–series cross–section analysis in comparative political economy — the constant–coefficients model — neither solves the small–N problem nor draws attention to dynamics over time. Thus, the article concludes that a sensitive interpretation of the findings obtained by advanced statistical methodology in comparative political economy is still dependent on small–N comparative analysis.     

Corrigendum - Sense and sensitivity in pooled analysis of political data

European Journal of Political Research -     

Developmental trends in television coviewing of parent-child dyads

In this study, long-term trends in joint parent-child television viewing are taken as prototype for developmental changes of the parent-child relationship during adolescence. To describe and compare trends of television coviewing in different configurations of family members, trajectories of daily television viewing, tmeasured with Nielsen-type people meters over a time period of three years, were analyzed using time series methods. The findings show the transferability of hypotheses about general developments in relations between the generations on coviewing behavior of adolescents aged 14–16 with their parents to predict differential declines in the four parent-child dyads.Received Ph.D. from Free University of Berlin in 1976. Research interests include the role of the media in child development and family relations.Received Ph.D. from Free University of Berlin in 1984. Research interests include time series analysis, television behavior, and personality.Received M.S. from Technical University of Berlin, in 1987. Research interests include role of television in political socialization.     

The Moore thesis: what's left after 1989?

This article reconsiders the work of Barrington Moore and his critics on the historical emergence of democracy in the light of post-communist democratization. What are we to make of a region which violates Moore's dictum – “No bourgeoisie, no democracy”? Using the tools of comparative historical analysis, it makes sense of how democracy emerged in the region by developing a theory which both explains why this was possible and what social actors were essential to this outcome. With attention to patterns of social development in the region, the politics of elite alliance in the final phase of communism, the strength of civil society at extrication, and the role of the international system, it explains differences in regime outcomes across the region.     

When and where do elections matter? A global test of the democratization by elections hypothesis, 1900–2010

Successive multiparty elections in sub-Saharan Africa are associated with incremental democratization. Yet tests in other regions are less than encouraging. Non-significant findings on Latin America and post-communist Eurasia, as well as conceptual criticism regarding the theory’s application in the contemporary Middle East, suggest that this may be a case of African exceptionalism. This article moves these debates forward by posing a comprehensive, global set of tests on the democratizing effect of elections. We seek to establish the scope conditions of the argument geographically, temporally, and substantively. Although we find a correlation between reiterated multiparty elections and improvements in the liberal-democratic components of electoral regimes globally since 1900, the relationship is only substantial in the period since the onset of the third wave of democracy. Experiences with iterated multiparty elections have substantive importance for democratization in sub-Saharan Africa, the post-communist region, Latin America and the Caribbean, and Asia. For the Middle East and North Africa, the relationship is weaker and less robust. Finally, the results suggest that reiterated sequences of multiparty elections are associated with improvements to liberal and deliberative components of democracy more so than egalitarian components.     

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The potential of artificial aging for modelling of natural aging processes of ballpoint ink

Artificial aging has been used to reproduce natural aging processes in an accelerated pace. Questioned documents were exposed to light or high temperature in a well-defined manner in order to simulate an increased age. This may be used to study the aging processes or to date documents by reproducing their aging curve. Ink was studied especially because it is deposited on the paper when a document, such as a contract, is produced. Once on the paper, aging processes start through degradation of dyes, solvents drying and resins polymerisation. Modelling of dye's and solvent's aging was attempted. These processes, however, follow complex pathways, influenced by many factors which can be classified as three major groups: ink composition, paper type and storage conditions. The influence of these factors is such that different aging states can be obtained for an identical point in time. Storage conditions in particular are difficult to simulate, as they are dependent on environmental conditions (e.g. intensity and dose of light, temperature, air flow, humidity) and cannot be controlled in the natural aging of questioned documents. The problem therefore lies more in the variety of different conditions a questioned document might be exposed to during its natural aging, rather than in the simulation of such conditions in the laboratory. Nevertheless, a precise modelling of natural aging curves based on artificial aging curves is obtained when performed on the same paper and ink. A standard model for aging processes of ink on paper is therefore presented that is based on a fit of aging curves to a power law of solvent concentrations as a function of time. A mathematical transformation of artificial aging curves into modelled natural aging curves results in excellent overlap with data from real natural aging processes.