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The German Twin Family Panel (TwinLife) is a German longitudinal study of monozygotic and dizygotic same-sex twin pairs and their families that was designed to investigate the development of social inequalities over the life course. The study covers an observation period from approximately 2014 to 2023. The target population of the sample are reared-together twins of four different age cohorts that were born in 2009/2010 (cohort 1), in 2003/2004 (cohort 2), in 1997/1998 (cohort 3) and between 1990 and 1993 (cohort 4). In the first wave, the study included data on 4097 twin families. Families were recruited in all parts of Germany so that the sample comprises the whole range of the educational, occupational and income structure. As of 2019, two face-to-face, at-home interviews and two telephone interviews have been conducted. Data from the first home and telephone interviews are already available free of charge as a scientific use-file from the GESIS data archive. This report aims to provide an overview of the study sample and design as well as constructs that are unique in TwinLife in comparison with previous twin studies — such as an assessment of cognitive abilities or information based on the children’s medical records and report cards. In addition, major findings based on the data already released are displayed, and future directions of the study are presented and discussed.
Leaf-cutting ants are dominant herbivores in Neotropical rain forests, and their colony densities increase in disturbed habitats such as forest edges. However, while it is well-established that leaf-cutting ants profit from changes to the food-plant community, the phylogenetic dimension of this ant–plant interaction remains poorly understood in fragmented forests. We studied diet composition of Atta cephalotes in the edge and interior of Atlantic forest in north-east Brazil (8°30′S, 35°50′W). We applied phylogenetic signal analysis to investigate the diet across plant lineages and performed phylogenetic generalized linear models to analyse the diet in both habitats. We found a phylogenetic signal in diet and in leaf mechanical resistance, which means that A. cephalotes selects closely related food plants with less resistant leaves. Most preferred species belong to Malpighiales, Rubiaceae and Melastomataceae. We also found that irrespective of phylogeny, ants select food plants with less resistant leaves, both in edge and interior. However, ants choose more abundant plants only in edges. High abundance of optimal diet facilitates foraging in forest edges and explains why colony densities increase in disturbed habitats. Finally, by favouring or disfavouring specific clades, leaf-cutting ants contribute to changes in the phylogenetic structure of tropical rain forests, e.g. phylogenetic impoverishment.
Miniaturization has been defined as the evolution of extremely small adult size in a lineage. It does not simply imply the decrease of the body size but also involves structural modifications to maintain functional efficiency at a strongly reduced size. Miniaturization has been proposed as a key factor in the origin of several major tetrapod clades. Current hypotheses propose that the living amphibians (lissamphibians) originated within a clade of Paleozoic dwarfed dissorophoid temnospondyls. Morphological traits shared by these small dissorophoids have been interpreted as resulting from constraints imposed by the extreme size reduction, but these statements were based only on qualitative observations. Herein, we assess quantitatively morphological changes in the skull previously associated with miniaturization in the lissamphibian stem lineage by comparing evolutionary and ontogenetic allometries in dissorophoids. Our results show that these features are not comparable to the morphological consequences of extreme size reduction as documented in extant miniature amphibians, but instead they resemble immature conditions of larger temnospondyls. We conclude that the truncation of the ancestral ontogeny, and not constraints related to miniaturization, might have been the factor that played a major role in the morphological evolution of small dissorophoids. Based on our results, we discuss the putative role of miniaturization in the origin of lissamphibians within Dissorophoidea.
HR 6902 was the first target of a systematic study by Griffin (1986, JApA, 7, 195) of binaries showing composite spectra. It is also a well-studied member of the ζ Aur class. ζ Aur systems are long-period eclipsing binaries that are comprised of an evolved giant primary and a hot dwarf companion. Although those component stars have very different effective temperatures they have similar luminosities in the blue and near-UV regions, and hence display a composite spectrum at those wavelengths. In principle the ζ Aur systems are excellent tests of evolutionary and structural stellar models. In recent years the somewhat fragmentary eclipse photometry of HR 6902 has been out-classed by the high-precision continuous monitoring by the space mission CoRoT. HR 6902 was selected as a primary target of its seismology field, because the possible detection of solar-like pulsations in a giant component of a double-lined eclipsing binary could help to calibrate the scaling relation of giant pulsators. Our poster reported the results of a new analysis based on the CoRoT observations and follow-up spectroscopy with HARPS at the ESO 3.6-m telescope at La Silla.
The unprecedented accuracy of the CoRoT photometry enabled us to:
improve drastically the accuracy of the binary orbit and stellar parameters (by a factor ~10 for the radii)
extend the test of validity/calibration of the scaling relations to high stellar mass and radius, and put constraints on the evolutionary state (particularly since this binary is certainly free from tidal effects).
Between 1999 and 2001, a 724 m long ice core was drilled on Akademii Nauk, the largest glacier on Severnaya Zemlya, Russian Arctic. The drilling site is located near the summit. The core is characterized by high melt-layer content. The melt layers are caused by melting and even by rain during the summer. We present high-resolution data of density, electrical conductivity (dielectrical profiling), stable water isotopes and melt-layer content for the upper 136m (120 m w.e.) of the ice core. The dating by isotopic cycles and electrical conductivity peak identification suggests that this core section covers approximately the past 275 years. Singularities of volcanogenic and anthropogenic origin provide well-defined additional time markers. Long-term temperatures inferred from 12 year running mean averages of δ18O reach their lowest level in the entire record around 1790. Thereafter the δ18O values indicate a continuously increasing mean temperature on the Akademii Nauk ice cap until 1935, interrupted only by minor cooling episodes. The 20th century is found to be the warmest period in this record.
There is some evidence for disk-halo connections in M31, i.e.: (1) The central area seems inclined w.r.t. the main disk. (2) In several regions in the southern half the magnetic field has a significant component perpendicular to the disk. However, (3) any general emission from a thick disk at λ75 cm is ~100x weaker than that from our Galaxy. The uniform disk field seems to inhibit cosmic-ray diffusion perpendicular to the plane, and/or the field at high z is exceptionally weak.
The German twin family study ‘TwinLife’ was designed to enhance our understanding of the development of social inequalities over the life course. The interdisciplinary project investigates mechanisms of social inequalities across the lifespan by taking into account psychological as well as social mechanisms, and their genetic origin as well as the interaction and covariation between these factors. Main characteristics of the study are: (1) a multidimensional perspective on social inequalities, (2) the assessment of developmental trajectories in childhood, adolescence, and young adulthood in a longitudinal design by using (3) a combination of a multi-cohort cross-sequential and an extended twin family design, while (4) capturing a large variation of behavioral and environmental factors in a representative sample of about 4,000 German twin families. In the present article, we first introduce the theoretical and empirical background of the TwinLife study, and second, describe the design, content, and implementation of TwinLife. Since the data will be made available as scientific use file, we also illustrate research possibilities provided by this project to the scientific community.
In recent years in California, smog aerosols have been observed in metropolitan and rural areas. We wondered what the relative contribution is from sources such as fossil fuel combustion (eg, cars, factories) and emissions from trees and other plants. Pollution produced by fossil fuel combustion can be distinguished from biological sources using radioactive carbon. Carbon in fossil organic materials is radioactively dead whereas carbon in living plants contains 14C. Smog particles were collected on clean glass or quartz fiber paper and analyzed in a small volume CO2 proportional counter for 14C content. Results are given for sampling locations at UCLA, El Monte, Riverside, and Lake Tahoe showing the relative contributions of fossil and modern carbon sources ranging from 0 to 74% and 26 to 100% respectively.
Because of the unique observational challenges -extreme crowding and extinction- any existing large-scale near-infrared (NIR) imaging data on the Galactic Center (GC) are limited by either one, or a combination, of the following: saturation, lack of sensitivity, too low angular resolution, or lack of multi-wavelength coverage. To overcome this situation, we are currently carrying out a sensitive, 0.2” resolution JHK imaging survey of the Galactic Centre with HAWK-I/VLT. Thanks to holographic imaging, we achieve a similar resolution than with HST/WFC, but can cover also the long NIR, beyond 2 micrometers, which is essential to deal with extinction. Our survey is supported by an ESO Large Programme and will provide photometrically accurate (few percent uncertainty for H < 18 stars), high-angular resolution, NIR data for an area of several 1000 pc2, a more than ten-fold increase compared to the current state of affairs. Here we present an overview and first results.
Absorbing material compressed in a number of thin shells is effectively less opaque for X-rays than smoothly distributed gas. The calculated X-ray emission-line profiles are red-shifted if the emission arises from the starward side of the shells.
We discuss the connection between wind overloading and discrete absorption components in P-Cygni line profiles from O-type stars. Overloading can create horizontal plateaus in the radial wind speed that cause the extra absorption in the line profile. The upstream propagation speed of these velocity plateaus is analyzed. The second part of the paper deals with X-ray emission from O-type stars. X-ray line profiles observed with Chandra and XMM-Newton are often symmetric, contrary to what is expected for lines from a homogeneous wind. We discuss the influence on line symmetry of photon escape channels in a strongly clumped wind.
The rapid increase in the prevalence of dementia associated with ageing populations has stimulated interest in identifying modifiable lifestyle factors that could prevent cognitive impairment. One such potential preventive lifestyle factor is the Nordic diet that has been shown to reduce the risk of CVD; however, its effect on cognition has not been studied. The aim of the present study was to estimate the cross-sectional and longitudinal associations of the baseline Nordic diet with cognitive function at baseline and after a 4-year follow-up in a population-based random sample (n 1140 women and men, age 57–78 years) as secondary analyses of the Finnish Dose-Responses to Exercise Training study. The Nordic diet score was created based on reported dietary components in 4-d food records. Cognition was assessed by the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychological battery and the Mini-mental State Examination (MMSE). The baseline Nordic diet score had been positively associated with Verbal Fluency (β 0·08 (95 % CI 0·00, 0·16), P= 0·039) and Word List Learning (β 0·06 (95 % CI 0·01, 0·10), P= 0·022) at 4 years but not with the Consortium to Establish a Registry for Alzheimer's Disease total score (CERAD-TS) or MMSE at 4 years, after adjustment for baseline cognitive scores, demographic factors and health-related factors. After excluding individuals with impaired cognition at baseline, the baseline Nordic diet score had also been positively associated with the CERAD-TS (β 0·10 (95 % CI 0·00, 0·20), P= 0·042) and MMSE (β 0·03 (95 % CI 0·00, 0·06), P= 0·039) at 4 years. These associations disappeared after further adjustment for energy intake. In conclusion, the Nordic diet might have a positive association with cognition in individuals with normal cognition.
Considerable interest in understanding interfacial phenomena occurring across nanostructured solid oxide fuel cell (SOFC) membrane electrode assemblies has increased demand for in situ characterization techniques with higher resolution. We briefly outline recent advancements in atomic force microscopy (AFM) instrumentation and subsystems in realizing real time imaging at high temperatures and ambient pressures, and the use of these in situ, multi-stimuli probes in collecting local information related to physical and fundamental processes. Here we demonstrate direct probing of local surface potential gradients related to the ionic conductivity of yttria-stabilized zirconia (YSZ) within symmetric SOFCs under intermediate operating temperatures (500–600 °C) via variable temperature scanning surface potential microscopy (VT-SSPM). The conductivity values obtained at different temperatures are then used to estimate the activation energy. These locally collected conductivity and activation energy values are subsequently compared to macroscopic electrochemical impedance results and bulk literature values, thus supporting the validity of the approach.
Intakes of saturated fat (SF) and dietary fibre, body mass and physical activity are all associated with the incidence of type 2 diabetes mellitus. Their relative importance for the maintenance of normal glucose metabolism is not fully known. In a population-based sample of 1114 individuals, aged 58–78 years, dietary intakes were assessed by 4 d food records and cardiorespiratory fitness as maximal oxygen uptake. Insulin secretion, insulin sensitivity, the early-phase disposition index (DI30) and the total disposition index (DI120) were assessed based on an oral glucose tolerance test. Linear associations were modelled using linear regression. Combined effects were studied by introducing SF and fibre intakes, as well as cardiorespiratory fitness and waist circumference (WC) as dichotomised variables in general linear models. Intakes of dietary fibre and whole-grain bread were positively associated with insulin sensitivity, independent of physical fitness and WC. In women, dietary fibre intake was also positively associated with DI30. The negative association of high WC with DI30 was attenuated by a combination of low SF intake and high cardiorespiratory fitness. In conclusion, dietary fibre and a combination of low SF intake and high cardiorespiratory fitness may contribute to the maintenance of normal glucose metabolism, independent of WC.
In the solar neighborhood, where the typical relaxation timescale is larger than the cosmic age, at least 10% to 15% of Sun-like stars have planetary systems with Jupiter-mass planets. In contrast, dense star clusters, characterized by frequent close encounters, have been found to host very few planets. We carry out numerical simulations with different initial conditions to investigate the dynamical stability of planetary systems in star cluster environments.
Triple supermassive black holes (SMBH) can form during the hierarchical mergers of massive galaxies with an existing binary. Perturbations by a third black hole may accelerate the merging process of an inner binary, for example through the Kozai mechanism. We analyze the evolution of simulated hierarchical triple SMBHs in galactic centers, and find resonances in the evolution of the semi-major axis, the eccentricity and the inclination, for both the inner and the outer orbits of the triple system, which are not only Kozai like. Through resonant oscillations, SMBH can trigger a significant increase of the inner SMBH binary eccentricity shortening the merger timescale expected from gravitational wave (GW) emission. As hierarchical triple SMBHs may be frequent in massive galaxies, the influence of orbital resonances is of great importance to our understanding of black hole coalescence and gravitational wave detection. Although Kozai mechanism is believed to play an important role in this process, detailed studies on the pattern of these resonances is necessary.