The COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) project is a large international collaborative effort to analyze individual-level phenotype data from twins in multiple cohorts from different environments. The main objective is to study factors that modify genetic and environmental variation of height, body mass index (BMI, kg/m2) and size at birth, and additionally to address other research questions such as long-term consequences of birth size. The project started in 2013 and is open to all twin projects in the world having height and weight measures on twins with information on zygosity. Thus far, 54 twin projects from 24 countries have provided individual-level data. The CODATwins database includes 489,981 twin individuals (228,635 complete twin pairs). Since many twin cohorts have collected longitudinal data, there is a total of 1,049,785 height and weight observations. For many cohorts, we also have information on birth weight and length, own smoking behavior and own or parental education. We found that the heritability estimates of height and BMI systematically changed from infancy to old age. Remarkably, only minor differences in the heritability estimates were found across cultural–geographic regions, measurement time and birth cohort for height and BMI. In addition to genetic epidemiological studies, we looked at associations of height and BMI with education, birth weight and smoking status. Within-family analyses examined differences within same-sex and opposite-sex dizygotic twins in birth size and later development. The CODATwins project demonstrates the feasibility and value of international collaboration to address gene-by-exposure interactions that require large sample sizes and address the effects of different exposures across time, geographical regions and socioeconomic status.

Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotypes is important for genetic twin modeling and for inferences made from twin studies in general. We analyzed whether there were differences in individual, maternal and paternal education between MZ and DZ twins in a large pooled dataset. Information was gathered on individual education for 218,362 adult twins from 27 twin cohorts (53% females; 39% MZ twins), and on maternal and paternal education for 147,315 and 143,056 twins respectively, from 28 twin cohorts (52% females; 38% MZ twins). Together, we had information on individual or parental education from 42 twin cohorts representing 19 countries. The original education classifications were transformed to education years and analyzed using linear regression models. Overall, MZ males had 0.26 (95% CI [0.21, 0.31]) years and MZ females 0.17 (95% CI [0.12, 0.21]) years longer education than DZ twins. The zygosity difference became smaller in more recent birth cohorts for both males and females. Parental education was somewhat longer for fathers of DZ twins in cohorts born in 1990–1999 (0.16 years, 95% CI [0.08, 0.25]) and 2000 or later (0.11 years, 95% CI [0.00, 0.22]), compared with fathers of MZ twins. The results show that the years of both individual and parental education are largely similar in MZ and DZ twins. We suggest that the socio-economic differences between MZ and DZ twins are so small that inferences based upon genetic modeling of twin data are not affected.

We analyzed birth order differences in means and variances of height and body mass index (BMI) in monozygotic (MZ) and dizygotic (DZ) twins from infancy to old age. The data were derived from the international CODATwins database. The total number of height and BMI measures from 0.5 to 79.5 years of age was 397,466. As expected, first-born twins had greater birth weight than second-born twins. With respect to height, first-born twins were slightly taller than second-born twins in childhood. After adjusting the results for birth weight, the birth order differences decreased and were no longer statistically significant. First-born twins had greater BMI than the second-born twins over childhood and adolescence. After adjusting the results for birth weight, birth order was still associated with BMI until 12 years of age. No interaction effect between birth order and zygosity was found. Only limited evidence was found that birth order influenced variances of height or BMI. The results were similar among boys and girls and also in MZ and DZ twins. Overall, the differences in height and BMI between first- and second-born twins were modest even in early childhood, while adjustment for birth weight reduced the birth order differences but did not remove them for BMI.

A trend toward greater body size in dizygotic (DZ) than in monozygotic (MZ) twins has been suggested by some but not all studies, and this difference may also vary by age. We analyzed zygosity differences in mean values and variances of height and body mass index (BMI) among male and female twins from infancy to old age. Data were derived from an international database of 54 twin cohorts participating in the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins), and included 842,951 height and BMI measurements from twins aged 1 to 102 years. The results showed that DZ twins were consistently taller than MZ twins, with differences of up to 2.0 cm in childhood and adolescence and up to 0.9 cm in adulthood. Similarly, a greater mean BMI of up to 0.3 kg/m2 in childhood and adolescence and up to 0.2 kg/m2 in adulthood was observed in DZ twins, although the pattern was less consistent. DZ twins presented up to 1.7% greater height and 1.9% greater BMI than MZ twins; these percentage differences were largest in middle and late childhood and decreased with age in both sexes. The variance of height was similar in MZ and DZ twins at most ages. In contrast, the variance of BMI was significantly higher in DZ than in MZ twins, particularly in childhood. In conclusion, DZ twins were generally taller and had greater BMI than MZ twins, but the differences decreased with age in both sexes.

For over 100 years, the genetics of human anthropometric traits has attracted scientific interest. In particular, height and body mass index (BMI, calculated as kg/m2) have been under intensive genetic research. However, it is still largely unknown whether and how heritability estimates vary between human populations. Opportunities to address this question have increased recently because of the establishment of many new twin cohorts and the increasing accumulation of data in established twin cohorts. We started a new research project to analyze systematically (1) the variation of heritability estimates of height, BMI and their trajectories over the life course between birth cohorts, ethnicities and countries, and (2) to study the effects of birth-related factors, education and smoking on these anthropometric traits and whether these effects vary between twin cohorts. We identified 67 twin projects, including both monozygotic (MZ) and dizygotic (DZ) twins, using various sources. We asked for individual level data on height and weight including repeated measurements, birth related traits, background variables, education and smoking. By the end of 2014, 48 projects participated. Together, we have 893,458 height and weight measures (52% females) from 434,723 twin individuals, including 201,192 complete twin pairs (40% monozygotic, 40% same-sex dizygotic and 20% opposite-sex dizygotic) representing 22 countries. This project demonstrates that large-scale international twin studies are feasible and can promote the use of existing data for novel research purposes.

The thermal conductivities of epoxy composites of mixtures of graphite and graphene in varying ratios were measured. Thermal characterization results showed unexpectedly high conductivities at a certain ratio filler ratio. This phenomenon was exhibited by samples with three different overall filler concentrations (graphene + graphite) of 7, 14, and 35 wt%. The highest thermal conductivity of 42.4 ± 4.8 W/m K (nearly 250 times the thermal conductivity of pristine epoxy) was seen for a sample with 30 wt% graphite and 5 wt% graphene when characterized using the dual-mode heat flow meter technique. This significant improvement in thermal conductivity can be attributed to the lowering of overall thermal interface resistance due to small amounts of nanofillers (graphene) improving the thermal contact between the primary microfillers (graphite). The synergistic effect of this hybrid filler system is lost at higher loadings of the graphene relative to graphite. Graphite and graphene mixed in the ratio of 6:1 yielded the highest thermal conductivities at three different filler loadings.

During the six weeks before the 2012 elections, we conducted a contest for the 54 students enrolled in an upper-division political science course on campaigns and elections. We modified and improved on a similar contest conducted by the first-named author (Abramson 2010) during the 2008 election campaign. Using contract prices posted by Intrade.com, an electronic gaming market in Dublin, we asked students to choose among 10 political outcomes. The contest was designed to help students learn about campaign strategies, understand how electoral rules affect political outcomes, and encourage them to talk about the campaign. We discuss ways we improved on Abramson’s 2008 contest and show that student participation increased substantially.

During the six weeks before the 2008 elections, I conducted a contest for the 72 students enrolled in my upper-division course Campaigns and Elections. Using contract prices posted by Intrade.com, an electronic gaming market based in Dublin, I asked students to choose among 10 political outcomes. The “contracts” earned by each choice were determined by the Intrade “bid” prices as of September 24, 2008, the day the contest began. The contest helped teach students about campaign strategies, the way electoral rules affect electoral outcomes, provided a reference point to discuss the campaign, and was designed to stimulate interest in the election.

The present study examined neuropsychological (NP) functioning and associated medical, neurological, brain magnetic resonance imaging (MRI), and psychiatric findings in 389 nondemented males infected with Human Immunodeficiency Virus-Type 1 (HIV-1), and in 111 uninfected controls. Using a comprehensive NP test battery, we found increased rates of impairment at each successive stage of HIV infection. HIV-related NP impairment was generally mild, especially in the medically asymptomatic stage of infection, and most often affected attention, speed of information processing, and learning efficiency; this pattern is consistent with earliest involvement of subcortical or frontostriatal brain systems. NP impairment could not be explained on the bases of mood disturbance, recreational drug or alcohol use, or constitutional symptoms; by contrast, impairment in HIV-infected subjects was related to central brain atrophy on MRI, as well as to evidence of cellular immune activation and neurological abnormalities linked to the central nervous system. (JINS, 1995, 1, 231–251.)

Ivor Crewe, Bo Särlvik and James Alt (‘Partisan Dealignment in Britain 1964–1974’, this Journal, VII (1977), 129–90) have made a major contribution to our understanding of partisan change in Britain. Whereas the declining share of the Conservative and Labour party vote can be documented through electoral statistics, Crewe and his colleagues focused on individual-level change in attitudes toward the parties, and thus provided valuable insights that help explain the dealignment that has occurred. One of their major findings was that the strength of party loyalties has declined among the British electorate. Building a measure of mean partisan strength that captures the distribution of ‘very strong’ identifiers, ‘fairly strong’ identifiers, ‘not very strong’ identifiers, and non-identifiers, they show a continuous decline in the strength of partisan loyalties between 1964 and October 1974. In 1964 the partisan strength of the electorate was 2·19; by October 1974 it had fallen to 1·90 (pp. 162–4). This overall decline is quite substantial, given that their measure of mean partisan strength ranges from 0·0 to 3·0.

The strong relationship between social class and partisan choice is one of the most extensively documented facts of British political life; but that relationship declined markedly during the 1960s, as Butler and Stokes have shown. Their lucid documentation of the declining class–party nexus is among the major findings of the second edition of their book, and, as class-based partisanship is particularly low among the young, many might conclude that the relationship between class and party will continue to decline in future. It would, however, be premature to reach this conclusion.

Surveys sponsored by the Commission of the European Communities are employed to study value change in West Germany, Britain, the Netherlands, France, Belgium and Italy between 1970–71 and 1990 and in Denmark and Ireland between 1973 and 1990. During these years generational replacement had a major impact on value trends in all eight societies. In Germany, Britain, the Netherlands and Denmark generational replacement contributed to the growth of Postmaterialism, and in France, Italy and Ireland replacement was the major force creating the trend towards Postmaterialism. Even in Belgium, where there was only a slight move towards Postmaterialism, replacement may have prevented a movement towards Materialism. For the European public as a whole, replacement contributed to the growth of Postmaterialism. However, the impact of replacement is likely to be smaller in the coming two decades because relatively low birth rates during the late 1970s and the 1980s will contribute to lower rates of generational replacement.

Converse's ‘Of Time and Partisan Stability’ presents one of the most elegant theories in political science. Analysing the surveys collected in Almond and Verba's five-nation study, Converse explains the micro-level processes that can contribute to partisan stability among mass electorates. If, as Campbell, Converse, Miller and Stokes argue, partisan loyalties contribute to electoral stability, Converse's theory has important implications, not only for electoral behaviour, but for democratic political stability as well.

The Israeli election for Prime Minister in 1999 featured five candidates. Three, including a major, centrally located candidate, Yitzhak Mordechai, withdrew from competition during the two days before the voting. Mordechai withdrew in large measure in reaction to the strategic decisions of voters, that is, some voters who favored him deserted his candidacy as his poll standings declined. We use surveys conducted during the 1999 campaign to estimate models of strategic voting behavior based on the multicandidate calculus of voting. We find that strategic voting in the Israeli, majority-with-runoff electoral system closely resembled the level and nature of strategic voting found in the more nearly pure plurality systems for which the statistical models were originally developed. The result is support for the reasoning Mordechai provided for his decision, illustrating the interlocking nature of strategic decisions between candidates and voters.