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.

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.

We review the present state of the understanding and application of high temperature superconductor materials ranging from attempts to clarify pairing mechanisms on the energy scale of a few milli-electron-volts to their use to embody terra-kwh continental wide deployment within the electricity enterprise. Examples include the use of density functional theory to study the relative roles of spin-fluctuation and/or lattice vibration induced Cooper pairing to modelling the incorporation of long distance HTSC transmission cables within the same natural gas pipeline rights-of-way infrastructure now emerging worldwide.

Natural tree canopy gaps allow sunlight to penetrate to the forest floor, a major environmental component and resource for many tropical rain-forest species. We compare here how butterflies use sunny areas created by the natural gaps in canopies in comparison with adjacent closed-canopy areas. We chose butterflies as our focal organisms as they are taxonomically tractable and mobile, yet habitat sensitive. Previous studies have shown that butterfly diversity in tropical forests responds to varying degrees of canopy openness. Here we assess butterfly behavioural responses to gaps and equivalent sized closed-canopy patches. Butterfly occupancy time and behaviour were simultaneously observed 61 times in gaps and 61 times in equivalent sized closed-canopy patches across four sites in a tropical rain forest in northern Borneo. Out of the 20 most frequently recorded species, 12 were more frequently recorded or spent more time in gaps, four occurred more frequently in closed-canopy areas, and four showed no significant differences. Overall agonistic, basking, patrolling and resting were more common in gaps compared with the closed canopy. Many butterfly species have complex behavioural requirements for both gaps and closed canopies, with some species using these different areas for different behaviours. Each butterfly species had particular habitat requirements, and needed both canopy gaps and closed canopy areas for ecological and behavioural reasons, emphasizing the need for natural light heterogeneity within these systems.

Despite the prevalence of HIV-associated episodic memory impairment and its adverse functional impact, there are no empirically validated cognitive rehabilitation strategies for HIV-infected persons. The present study examined the self-generation approach, which is theorized to enhance new learning by elaborating and deepening encoding. Participants included 54 HIV-infected and 46 seronegative individuals, who learned paired word associates in both self-generated and didactic encoding experimental conditions. Results revealed main effects of HIV serostatus and encoding condition, but no interaction. Planned comparisons showed that both groups recalled significantly more words learned in the self-generation condition, and that HIV+ individuals recalled fewer words overall compared to their seronegative counterparts at delayed recall. Importantly, HIV+ participants with clinical memory impairment evidenced similar benefits of self-generation compared to unimpaired HIV+ subjects. Self-generation strategies may improve verbal recall in individuals with HIV infection and may, therefore, be an appropriate and potentially effective cognitive rehabilitation tool in this population. (JINS, 2012, 18, 128–133)

Methyl depletion and subsequent moisture uptake have been found to be the primary plasma damages leading to dielectric loss in porous organosilicate (OSG) low-k dielectrics. A vacuum vapor silylation process was developed for dielectric recovery of plasma damaged OSG low-k dielectrics. The methyl or phenyl containing silylation agents were used to convert the hydrophilic -OH groups to hydrophobic groups. Compared with Trimethylchlorosilane (TMCS) and Phenyltrimethoxysilane (PTMOS), Dimethyldichlorosilane (DMDCS) was found to be more effective in recovering surface carbon concentration and surface hydrophobicity. But the carbon recovery effect was limited to the surface region.

Alternatively, UV radiation with thermal activation was applied for dielectric recovery of plasma damaged OSG low-k dielectrics. The combined UV/thermal process was found to be efficient in reducing −OH, physisorbed water, and C=O bonds. The dielectric constant was recovered within 5% of the pristine sample and the leakage current was also much reduced. Aging test in air showed that no moisture retake was observed, indicating the repaired film was stable.

During an O2 plasma ashing process, carbon depletion and subsequent moisture uptake caused increase of keff and the leakage current in an organosilicate (OSG) low-k dielectric. For dielectric restoration, additional CH4 plasma treatment on the O2 plasma ashed OSG low-k dielectric was investigated using angle resolved x-ray photoelectron spectroscopy (ARXPS), XPS depth profiling, x-ray reflectivity (XRR), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and contact angle goniometer. After CH4 plasma treatment on the O2 plasma ashed OSG, the surface carbon concentration and surface hydrophobicity were partially recovered. A dense surface layer containing C=C bonds was found to have formed on the top of the damaged OSG. The C-V hysteresis and the leakage current were reduced as a result of the CH4 plasma treatment. XPS depth profiling revealed that the recovery effect was limited to the surface region.

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.