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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.
According to contemporary observers, George Ruggle's Ignoramus, first staged at Cambridge in March 1614, enjoyed an immense success, or notoriety, both at the university and at “Whitehall while it sent shockwaves through the Inns of Court and infuriated Sir Edward Coke, Lord Chief Justice of the King's Bench. The comedy was apparently conceived as an attack upon Francis Brackyn, Recorder of Cambridge and constant adversary of the university, but because of its brilliant and merciless satire of legal jargon, the play achieved a universality which aided James I and the civilian lawyers in their jurisdictional struggles against Coke and the common law bench.
Across the southeastern United States, pyridine carboxylic acid herbicides are widely used for broadleaf weed control in permanent grass pastures. This family of herbicides has proved very successful for controlling most broadleaf weeds commonly present in southeastern pastures and hayfields. In the southern United States, producers have expressed concern when overseeding legume species into warm-season perennial sods following application of commonly used pyridine carboxylic acid herbicides, as legumes are generally highly sensitive to this herbicide family. Field experiments were established to evaluate two herbicide treatment programs (residual vs nonresidual) on crimson clover overseeded into bermudagrass sod. The residual herbicide program included aminopyralid plus 2,4-D (0.09 + 0.7 kg ae ha–1), and the nonresidual program included triclopyr plus fluroxypyr (0.63 + 0.21 kg ae ha–1) plus 2,4-D (1.12 kg ae ha–1). Herbicide programs were applied at two key timings: in spring (May) and early summer (June). Spring applications were also evaluated when used in single vs repeated annual application. Our results did not indicate soil residual herbicide issues for crimson clover planted in the fall following spring or early-summer application of aminopyralid + 2,4-D at either location. Additionally, there were no cumulative negative impacts on crimson clover following 2 yr of spring herbicide application. Crimson clover cover, however, strongly decreased as grass and weed cover increased––an event that may be related to greater interspecific competition at higher levels of grass and weed cover. Soil fertility, weather, and competition from resident annual grasses and weeds strongly influenced productivity, suggesting that changes in pasture dynamics had a greater influence on clover productivity than did herbicide treatment or timing of application.
The discovery of the first electromagnetic counterpart to a gravitational wave signal has generated follow-up observations by over 50 facilities world-wide, ushering in the new era of multi-messenger astronomy. In this paper, we present follow-up observations of the gravitational wave event GW170817 and its electromagnetic counterpart SSS17a/DLT17ck (IAU label AT2017gfo) by 14 Australian telescopes and partner observatories as part of Australian-based and Australian-led research programs. We report early- to late-time multi-wavelength observations, including optical imaging and spectroscopy, mid-infrared imaging, radio imaging, and searches for fast radio bursts. Our optical spectra reveal that the transient source emission cooled from approximately 6 400 K to 2 100 K over a 7-d period and produced no significant optical emission lines. The spectral profiles, cooling rate, and photometric light curves are consistent with the expected outburst and subsequent processes of a binary neutron star merger. Star formation in the host galaxy probably ceased at least a Gyr ago, although there is evidence for a galaxy merger. Binary pulsars with short (100 Myr) decay times are therefore unlikely progenitors, but pulsars like PSR B1534+12 with its 2.7 Gyr coalescence time could produce such a merger. The displacement (~2.2 kpc) of the binary star system from the centre of the main galaxy is not unusual for stars in the host galaxy or stars originating in the merging galaxy, and therefore any constraints on the kick velocity imparted to the progenitor are poor.
The SkyMapper Transient survey (SMT) is exploring variability in the southern sky by performing (a) a rolling search to discover and study supernovæ, and (b) a Target of Opportunity programme that uses the robotic SkyMapper Telescope at Siding Spring Observatory. The supernova survey is obtaining a non-targeted sample of Type Ia supernovæ (SNe Ia) at low redshifts, z < 0.1, and studying other interesting transients found with the search strategy. We have a Target of Opportunity programme with an automatic response mechanism to search for optical counterparts to gravitational-wave and fast radio-burst events; it benefits from SkyMapper’s large field of view of 5.7 sq. deg. and a rapid data reduction pipeline.
We present first results of the SMT survey. The SMT pipeline can process and obtain potential candidates within 12 hours of observation. It disentangles real transients from processing artefacts using a machine-learning algorithm. To date, SMT has discovered over 60 spectroscopically confirmed supernovæ, several peculiar objects, and over 40 SNe Ia including one (SNIa 2016hhd) which was found within the first few days of explosion. We have also participated in searches for optical counterparts of gravitational waves, fast radio bursts and other transients, and have published observations of the optical counterpart of the gravitational-wave event GW170817. We also participate in coordinated observations with the Deeper Wider Faster programme, and the Kepler K2 cosmology project.
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 SkyMapper 1.3 m telescope at Siding Spring Observatory has now begun regular operations. Alongside the Southern Sky Survey, a comprehensive digital survey of the entire southern sky, SkyMapper will carry out a search for supernovae and other transients. The search strategy, covering a total footprint area of ~2 000 deg2 with a cadence of ⩽5 d, is optimised for discovery and follow-up of low-redshift type Ia supernovae to constrain cosmic expansion and peculiar velocities. We describe the search operations and infrastructure, including a parallelised software pipeline to discover variable objects in difference imaging; simulations of the performance of the survey over its lifetime; public access to discovered transients; and some first results from the Science Verification data.
During March-May 1976, a combination of laser and radar ranging systems was used to study the motion of both the fast ice and the pack ice near Narwhal and Cross Islands, two barrier islands located 16 and 21 km offshore in the vicinity of Prudhoe Bay, Alaska. Laser measurements of targets on the fast ice near Narwhal Island indicate small net displacements of approximately 1 m over the period of study (71 d) with short-term displacements of up to 40 cm occurring over 3 d periods. The main motion was outward normal to the coast and was believed to be the result of thermal expansion of the ice. The radar records of fast-ice sites farther offshore show a systematic increase in the standard deviation of the displacements as measured parallel to the coast, reaching a value of ±6.6 m at 31 km. The farthest fast-ice sites show short-term displacements of up to 12 m. There are also trends in the records that are believed to be the result of the general warming of the fast ice with time.
Radar targets located on the pack ice showed large short-term displacements (up to 2.7 km) but negligible net ice drift along the coast. There was no significant correlation between the movement of the pack and the local wind, suggesting that coastal ice prediction models can only succeed if handled as part of a regional model which incorporates stress transfer through the pack. The apparent fast-ice-pack-ice boundary in the study area was located in 30-35 m of water.
Cortisol is the primary output of the hypothalamic–pituitary–adrenal (HPA) axis and is central to the biological stress response, with wide-ranging effects on psychiatric health. Despite well-studied biological pathways of glucocorticoid function, little attention has been paid to the role of genetic variation. Conventional salivary, urinary and serum measures are strongly influenced by diurnal variation and transient reactivity. Recently developed technology can be used to measure cortisol accumulation over several months in hair, thus indexing chronic HPA function.
In a socio-economically diverse sample of 1070 twins/multiples (ages 7.80–19.47 years) from the Texas Twin Project, we estimated effects of sex, age and socio-economic status (SES) on hair concentrations of cortisol and its inactive metabolite, cortisone, along with their interactions with genetic and environmental factors. This is the first genetic study of hair neuroendocrine concentrations and the largest twin study of neuroendocrine concentrations in any tissue type.
Glucocorticoid concentrations increased with age for females, but not males. Genetic factors accounted for approximately half of the variation in cortisol and cortisone. Shared environmental effects dissipated over adolescence. Higher SES was related to shallower increases in cortisol with age. SES was unrelated to cortisone, and did not significantly moderate genetic effects on either cortisol or cortisone.
Genetic factors account for sizable proportions of glucocorticoid variation across the entire age range examined, whereas shared environmental influences are modest, and only apparent at earlier ages. Chronic glucocorticoid output appears to be more consistently related to biological sex, age and genotype than to experiential factors that cluster within nuclear families.
The Dark Energy Survey is undertaking an observational programme imaging 1/4 of the southern hemisphere sky with unprecedented photometric accuracy. In the process of observing millions of faint stars and galaxies to constrain the parameters of the dark energy equation of state, the Dark Energy Survey will obtain pre-discovery images of the regions surrounding an estimated 100 gamma-ray bursts over 5 yr. Once gamma-ray bursts are detected by, e.g., the Swift satellite, the DES data will be extremely useful for follow-up observations by the transient astronomy community. We describe a recently-commissioned suite of software that listens continuously for automated notices of gamma-ray burst activity, collates information from archival DES data, and disseminates relevant data products back to the community in near-real-time. Of particular importance are the opportunities that non-public DES data provide for relative photometry of the optical counterparts of gamma-ray bursts, as well as for identifying key characteristics (e.g., photometric redshifts) of potential gamma-ray burst host galaxies. We provide the functional details of the DESAlert software, and its data products, and we show sample results from the application of DESAlert to numerous previously detected gamma-ray bursts, including the possible identification of several heretofore unknown gamma-ray burst hosts.
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 present results from an end-to-end simulation pipeline of interferometric observations of cosmic microwave background polarization. We use both maximum-likelihood and Gibbs sampling techniques to estimate the power spectrum. In addition, we use Gibbs sampling for image reconstruction from interferometric visibilities. The results indicate the level to which various systematic errors (e.g., pointing errors, gain errors, beam shape errors, cross polarization) must be controlled in order to successfully detect and characterize primordial B modes and achieve other scientific goals. In addition, we show that Gibbs sampling is an effective method of image reconstruction for interferometric data in other astrophysical contexts.
Atomic layer deposition (ALD) has been used to coat SBA-15 and functionalized SBA-15 with various metal oxides. Use of SBA-15 coated with 4-10 ALD cycles of titania, alumina, niobia, or zirconia in the acid-catalyzed dehydration of fructose to 5-hydroxymethylfurfural (HMF) resulted in 24-57% conversion, with 0-22% selectivity, at 130 °C with 2 wt % fructose in 4:1 THF:H2O. Propylsulfonic acid functionalized SBA-15 (SBA-15-PrSO3H) had a 25% conversion and 48% selectivity for HMF under the same conditions. SBA-15-PrSO3H was also coated with 2 ALD cycles of titania followed by 8 ALD cycles silica. The deactivation rate constant for SBA-15-PrSO3H was 2.7 x 10-2 h-1 for the dehydration of fructose to HMF in a flow reactor at 130 °C with a feed of 2 wt % fructose in 4:1 THF:H2O. In comparison, the deactivation rate constant for the ALD coated SBA-15-PrSO3H-ALD was 7.9 x 10-3 h-1.
238Pu-substituted zirconolite (CaPuTi 2O7 ) was stored near ambient temnerature for 231 days, equivalent to an aipha decay dose of 3.1×1025 α/m3 or 3×105 years of storage time for SYNROC ceramic nuclear waste. Periodic indentation testing showed that hardness was decreased by alpha decay-induced conversion to the metamict state, while fracture toughness and resistance to cracking were increased, apparently as a consequence of the formation of a heterogeneous microstructure. These results imply improved stability of this nuclear waste phase as a result of self-irradiation damage.
Transmission electron microscopy (TEM) was used to investigate the interfacial microstructures and phases involved in the nucleation and growth of the oriented diamond on Ni substrates by a multi-step growth process. A molten surface layer is formed during the process, which appears to be critical for both promotion of the diamond nucleation and suppression of graphite formation. Cross-section TEM analysis revealed that a polycrystalline nickel carbide interfacial structure exists between the diamond particles and the single crystal Ni substrate. X-ray diffraction analysis (XRD) identified the carbide phase as Ni4C. It is suggested that the Ni4C is formed in the molten layer and stabilizes sp3C precursor for diamond nucleation.
(100) and (111) oriented diamond films were grown on similarly oriented single crystal Ni substrates using a multi-step seeding and growth process. In-situ reflection monitoring revealed large surface reflectivity changes upon heating of the seeded substrate in H2. The reflectivity change was attributed to the surface melting and dissolution of the seeding particles. The presence of atomic hydrogen lowered the eutectic melting point of the Ni-C compound from 1325°C to about 1100°C. It appeared that the molten Ni-C-H surface layer suppressed graphite formation, which is normally observed in diamond growth on Ni, and promoted diamond nucleation. The oriented diamond films were also obtained using non-diamond carbon seeding. Based on experimental observation, a proposed model is described to explain the nucleation mechanism from the molten Ni-C-H surface layer.
Patterning on the 10 Å size scale has been achieved with a UHV-STM for Si(100)-2×1:H surfaces. Hydrogen passivation serves as a monolayer resist which the STM locally desorbs, exposing clean Si(100)-2×1 for selective chemistry. Two mechanisms have been identified for hydrogen removal by STM electrons: in the field emission regime direct electron stimulated desorption of hydrogen occurs whereas, in the lower energy tunneling regime, hydrogen desorption results from vibrational excitation of the Si-H bond at high tunneling currents. Furthermore, we find that atomic hydrogen is liberated in contrast to molecular hydrogen evolved during thermal desorption. Selective oxidation and nitridation of the STM-patterned areas has been achieved.
SiC has attracted great interest for high power microwave applications because of its superior intrinsic properties compared to Si and GaAs. Steady demonstrations of increasingly higher power handling capability have been achieved in recent years. However, SiC MESFETs still suffer from significant drain current degradation under RF operation or long-term DC stress. This degradation can be recovered after long periods of relaxation or immediately by illumination under UV light, which is indicative of a trapping effect. The origin of this effect has been attributed to either electron trapping at the device surface between the gate and drain or trapping at the epi-substrate interface due to the presence of electrically active contaminants in the bulk. Newly available “high purity” (non-vanadium compensated) bulk 4H semi-insulating SiC substrates were used in an effort to limit the effect of V-related deep level trapping at the substrate/epilayer interface. To investigate the effect of V on SiC MESFET performance, we compare similar devices fabricated on V compensated, and “high-purity” 4H-SiC substrates without intentional V doping. Presence or absence of V is confirmed by secondary ion mass spectrometry (SIMS) analysis. Pulsed I-V measurements as well as current- and capacitance-based deep level transient spectroscopy (DLTS) measurements were performed to assess trapping activation energy and density. An assessment of device performance and stability for each substrate type is made using RF load-pull measurements and device long-term DC bias stressing at temperature.
Over an order of magnitude reduction in dark current was observed for gas-source molecular beam epitaxially (GSMBE) grown, lattice-matched n- and p-type InGaAs/InP quantum-well infrared photodetectors (QWIPs). Peak spectral response at 8.93 and 4.55 μm for n- and p-type QWIPs, respectively, open the possibility of dual-band monolithic integration under identical GSMBE growth conditions.