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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.
We present an indentation-scope that interfaces with confocal microscopy, enabling direct observation of the three-dimensional (3D) microstructural response of coatings on substrates. Using this method, we compared microns-thick polymer coatings on glass with and without silica nanoparticle filler. Bulk force data confirmed the >30% modulus difference, while microstructural data further revealed slip at the glass-coating interface. Filled coatings slipped more and about two times faster, as reflected in 3D displacement and von Mises strain fields. Overall, these data indicate that silica-doping of coatings can dramatically alter adhesion. Moreover, this method compliments existing theoretical and modeling approaches for studying indentation in layered systems.
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.
The Square Kilometre Array will be an amazing instrument for pulsar astronomy. While the full SKA will be sensitive enough to detect all pulsars in the Galaxy visible from Earth, already with SKA1, pulsar searches will discover enough pulsars to increase the currently known population by a factor of four, no doubt including a range of amazing unknown sources. Real time processing is needed to deal with the 60 PB of pulsar search data collected per day, using a signal processing pipeline required to perform more than 10 POps. Here we present the suggested design of the pulsar search engine for the SKA and discuss challenges and solutions to the pulsar search venture.
The unique phenotypic and genetic aspects of obsessive-compulsive (OCD) and attention-deficit/hyperactivity disorder (ADHD) among individuals with Tourette syndrome (TS) are not well characterized. Here, we examine symptom patterns and heritability of OCD and ADHD in TS families.
OCD and ADHD symptom patterns were examined in TS patients and their family members (N = 3494) using exploratory factor analyses (EFA) for OCD and ADHD symptoms separately, followed by latent class analyses (LCA) of the resulting OCD and ADHD factor sum scores jointly; heritability and clinical relevance of the resulting factors and classes were assessed.
EFA yielded a 2-factor model for ADHD and an 8-factor model for OCD. Both ADHD factors (inattentive and hyperactive/impulsive symptoms) were genetically related to TS, ADHD, and OCD. The doubts, contamination, need for sameness, and superstitions factors were genetically related to OCD, but not ADHD or TS; symmetry/exactness and fear-of-harm were associated with TS and OCD while hoarding was associated with ADHD and OCD. In contrast, aggressive urges were genetically associated with TS, OCD, and ADHD. LCA revealed a three-class solution: few OCD/ADHD symptoms (LC1), OCD & ADHD symptoms (LC2), and symmetry/exactness, hoarding, and ADHD symptoms (LC3). LC2 had the highest psychiatric comorbidity rates (⩾50% for all disorders).
Symmetry/exactness, aggressive urges, fear-of-harm, and hoarding show complex genetic relationships with TS, OCD, and ADHD, and, rather than being specific subtypes of OCD, transcend traditional diagnostic boundaries, perhaps representing an underlying vulnerability (e.g. failure of top-down cognitive control) common to all three disorders.
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.
The photochemistry of CO and its isotoplogues affects the structure and evolution of many astronomical environments, including interstellar clouds, circumstellar disks around newly formed stars, and the envelopes surrounding highly evolved stars. When in the presence of a strong ultraviolet field, the primary destruction mechanism for interstellar and circumstellar CO is photodissociation, which is entirely governed by discrete line absorption into predissociating levels in the wavelength range 91.2 to 111.8 nm. Because the CO spectrum consists primarily of resolved line features, self-shielding effects in high-column density environments can lead to strong isotopic fractionation signatures in both CO and elemental oxygen and carbon; for example, CO self-shielding in the solar nebula has been invoked to explain the unusual oxygen isotope ratios observed in the earliest solar system condensates, viz. calcium-aluminum inclusions (CAIs) in primitive meteorites.
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 present analysis aimed to investigate the changes in the reported portion sizes (PS) of foods and beverages commonly consumed by Irish adults (18–64 years) from the North South Ireland Food Consumption Survey (NSIFCS) (1997–2001) and the National Adult Nutrition Survey (NANS) (2008–10). Food PS, which are defined as the weight of food (g) consumed per eating occasion, were calculated for comparable foods and beverages in two nationally representative cross-sectional Irish food consumption surveys and were published in NSIFCS and NANS. Repeated measure mixed model analysis compared reported food PS at the total population level as well as subdivided by sex, age, BMI and social class. A total of thirteen commonly consumed foods were examined. The analysis demonstrated that PS significantly increased for five foods (‘white sliced bread’, ‘brown/wholemeal breads’, ‘all meat, cooked’, ‘poultry, roasted’ and ‘milk’), significantly decreased for three (‘potatoes’, ‘chips/wedges’ and ‘ham, sliced’) and did not significantly change for five foods (‘processed potato products’, ‘bacon/ham’, ‘cheese’, ‘yogurt’ and ‘butter/spreads’) between the NSIFCS and the NANS. The present study demonstrates that there was considerable variation in the trends in reported food PS over this period.
Antarctic and Southern Ocean science is vital to understanding natural variability, the processes that govern global change and the role of humans in the Earth and climate system. The potential for new knowledge to be gained from future Antarctic science is substantial. Therefore, the international Antarctic community came together to ‘scan the horizon’ to identify the highest priority scientific questions that researchers should aspire to answer in the next two decades and beyond. Wide consultation was a fundamental principle for the development of a collective, international view of the most important future directions in Antarctic science. From the many possibilities, the horizon scan identified 80 key scientific questions through structured debate, discussion, revision and voting. Questions were clustered into seven topics: i) Antarctic atmosphere and global connections, ii) Southern Ocean and sea ice in a warming world, iii) ice sheet and sea level, iv) the dynamic Earth, v) life on the precipice, vi) near-Earth space and beyond, and vii) human presence in Antarctica. Answering the questions identified by the horizon scan will require innovative experimental designs, novel applications of technology, invention of next-generation field and laboratory approaches, and expanded observing systems and networks. Unbiased, non-contaminating procedures will be required to retrieve the requisite air, biota, sediment, rock, ice and water samples. Sustained year-round access to Antarctica and the Southern Ocean will be essential to increase winter-time measurements. Improved models are needed that represent Antarctica and the Southern Ocean in the Earth System, and provide predictions at spatial and temporal resolutions useful for decision making. A co-ordinated portfolio of cross-disciplinary science, based on new models of international collaboration, will be essential as no scientist, programme or nation can realize these aspirations alone.
Amphibian populations have been declining worldwide, with multiple potential causes. At La Selva field station in north-eastern Costa Rica, previous work has shown that populations of many amphibians have decreased significantly since the 1970s, especially in primary forest. Starting in 1998, we investigated one of the most common frog species at La Selva, the poison-dart frog Oophaga pumilio (= Dendrobates pumilio). In a survey of 50 plots of 100 m2 in 1998, adult frogs were 4.6 times more abundant in secondary forest than in primary forest. Tadpoles were found only in secondary-forest plots. Almost all (89%) of the tadpoles were found in leaf axils of Dieffenbachia spp., which were much more abundant in secondary-forest than in primary-forest plots. The greater abundance of Dieffenbachia spp. in secondary forest was confirmed in a broad survey of ~11 km of trails within La Selva in 2002. When the same trails were resampled in 2012, Dieffenbachia spp. had been extirpated from 72% of the 50-m segments where plants were present in 2002; abundance was greatly reduced in the few trail segments where any Dieffenbachia spp. remained in 2012. The loss of Dieffenbachia spp., especially in secondary forest, removed the species most often used by O. pumilio for tadpole rearing. Based on counts of calling frogs in 2010, there was no difference in O. pumilio abundance in primary versus secondary forest, in striking contrast to multiple earlier surveys that found much greater frog abundance in secondary forest. We propose that the reason for the rapid decline in Dieffenbachia spp. is herbivory by the collared peccary (Pecari tajacu), which has increased in abundance at La Selva in recent years. A likely consequence is continued reduction in O. pumilio populations.
In January and February 2009, a series of water samples were collected from streams on Byers Peninsula. These samples were analysed for major elements and δ18O to determine the role of lithology and landscape position on stream geochemistry, and to understand better the hydrology (i.e. residence time of water) of these systems. Precipitation chemistry is enriched in Na+, as are the streams located close to the coast. Streams originating from inland locations have much higher percentages of Ca2+. In contrast, Mg2+ varied little, though streams that are in greater contact with volcanic-derived soils have slightly higher concentrations. Anion percentages varied greatly between streams with SO42- ranging from 5% to 45% of the anion composition. Dissolved Si concentrations as high as 141 μM were observed. All these data suggest that active chemical weathering is occurring in this region. A time series over 13 days at one stream showed little variation in major element geochemistry. The δ18O of precipitation samples collected over this same period varied by ∼10‰ while the majority of stream samples varied less than ∼1.5‰. These data indicate that the stream waters represent mixtures of precipitation events, melting snow and water from the subsurface that had gained solutes through chemical weathering.
In an outbreak of measles in North Wales centred on a secondary school in 1991, 74 cases occurred over a period of 51 days. Before the outbreak started, 27 % pupils did not have a history of measles or immunization and were considered susceptible. Active case rinding and identification and vaccination of susceptible contacts commenced after the fourth generation of cases and further reduced the pool of susceptible schoolchildren from 17%, at the onset of the vaccination campaign, to 8%. A fifth generation of cases did not occur. Delays in diagnosis (mean 2·8 days) and notification (mean 6·1 days) hampered control. There was no evidence of primary vaccine failure (observed vaccine efficacy 97%). Sixty-nine (93%) cases were considered preventable. Reasons for the apparent success of the intervention are discussed.
The quasi-linear concept of plateau formation along resonant diffusion surfaces is compared with the time evolution of the electron distribution function during a computer simulation experiment of whistler-mode waves in unstable plasmas. It is found that, as the wave intensities grow, plateau formation does indeed occur, with the distribution function becoming constant along diffusion surfaces at the time when wave intensities maximize. Following the formation of the plateaus, both the wave intensities and the slope of the distribution function along diffusion surfaces oscillate in a manner suggesting msh;mode coupling. Tbe slope of the distribution function along diffusion surfaces, which controls the linear wave growth rate, also gives good predictions of the sign of the actual wave growth rate during the experiment.