The problem of zygosity misclassification of twins has been paid little attention in Japan. By analyzing maternal reports collected using an internet questionnaire, the author found that around 30% of monozygotic twins were misclassified as dizygotic twins, mainly by obstetricians. On the other hand, the percentage of dizygotic twin pairs misclassified as monozygotic twins was lower. Misclassif...

This study investigated the factor structure and etiology of four self-report schizotypy questionnaires during young adulthood (age 18-27) in 98 monozygotic and 59 same-sex dizygotic twin pairs from the community. A single phenotypic factor was identified that was primarily associated with Perceptual Aberration, Magical Ideation, and the Rust Inventory of Schizotypal Cognitions scales, and less...

The aim of this study was to identify genetic covariants for fundamental measures of brain function (event-related potentials (ERPs): P300 latency and slow wave amplitude recorded in a working-memory task) and more complex cognitive measures (behavioral non-ERP measures: working-memory performance, information processing speed, IQ). Data were collected from 252 monozygotic and 297 dizygotic twi...

We studied the age-related differences in inspection time and multiple cognitive domains in a group of monozygotic (MZ) and dizygotic (DZ) twins aged 7 to 17 years. Data from 111 twin pairs and 19 singleton siblings were included. We found clear agerelated trends towards more efficient visual information processing in older participants. There were substantial correlations between inspection ti...

We report on several features in the energy spectrum from an ultralow-noise germanium detector operated deep underground. By implementing a new technique able to reject surface events, a number of cosmogenic peaks can be observed for the first time. We discuss an irreducible excess of bulklike events below 3 keV in ionization energy. These could be caused by unknown backgrounds, but also dark m...

Large-scale patterns of spatial variation in species geographic range size are central to many fundamental questions in macroecology and conservation biology. However, the global nature of these patterns has remained contentious, since previous studies have been geographically restricted and/or based on small taxonomic groups. Here, using a database on the breeding distributions of birds, we re...

I should like to share with you our experiences in studying identical twins discordant for schizophrenia, for I believe that these investigations have taught us a number of lessons about the problems inherent in research on schizophrenia. I also feel fairly confident that they have brought us closer to the long-hoped-for day when some answers to the schizophrenia conundrum will be forthcoming. ...

OBJECTIVES To estimate annual changes and trends in the population of informal carers and to investigate transitions to caregiving by age, gender, locus of care, and level of involvement. DESIGN Longitudinal analysis of data from the British household panel survey, 1991 to 1998, an annual prospective survey of a nationally representative sample of more than 5000 private households in England,...

This study analyses the formant dynamics of Mandarin and Shanghainese /ua/ in bilingual identical twins. The results show that despite the same organic structure and similar language environment, differences can be found in their formant dynamics. A comparison between the subjects’ dominant and non-dominant language shows that the twins are more similar in their dominant language. The data also...

It has long been common knowledge that certain twins resemble one another in a remarkable way. The fact that many more like sexed twins are born than the theoretical ratio 1: 2: 1 would demand constitutes evidence in favour of the belief that such twins are monozygotic, for the actual figures of twin births can be adequately explained on the assumption that about one half the pairs of like sexe...