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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.
Methods are presented for the determination of uranium, or uranium and neptunium, in plutonium metal and plutonium alloys. Anion exchange or a combination of anion exchange - solvent extraction is used to concentrate the elements for x-ray fluorescence analysis, depending upon the impurities present and the elements to be determined. The precision for determining between 3 and 250 μg of uranium or neptunium ranges “between 30 and 2%.
Hill (Twin Research and Human Genetics, Vol. 21, 2018, 84–88) presented a critique of our recently published paper in Cell Reports entitled ‘Large-Scale Cognitive GWAS Meta-Analysis Reveals Tissue-Specific Neural Expression and Potential Nootropic Drug Targets’ (Lam et al., Cell Reports, Vol. 21, 2017, 2597–2613). Specifically, Hill offered several interrelated comments suggesting potential problems with our use of a new analytic method called Multi-Trait Analysis of GWAS (MTAG) (Turley et al., Nature Genetics, Vol. 50, 2018, 229–237). In this brief article, we respond to each of these concerns. Using empirical data, we conclude that our MTAG results do not suffer from ‘inflation in the FDR [false discovery rate]’, as suggested by Hill (Twin Research and Human Genetics, Vol. 21, 2018, 84–88), and are not ‘more relevant to the genetic contributions to education than they are to the genetic contributions to intelligence’.
Prior research has documented shared heritable contributions to non-suicidal self-injury (NSSI) and suicidal ideation (SI) as well as NSSI and suicide attempt (SA). In addition, trauma exposure has been implicated in risk for NSSI and suicide. Genetically informative studies are needed to determine common sources of liability to all three self-injurious thoughts and behaviors, and to clarify the nature of their associations with traumatic experiences.
Multivariate biometric modeling was conducted using data from 9526 twins [59% female, mean age = 31.7 years (range 24–42)] from two cohorts of the Australian Twin Registry, some of whom also participated in the Childhood Trauma Study and the Nicotine Addiction Genetics Project.
The prevalences of high-risk trauma exposure (HRT), NSSI, SI, and SA were 24.4, 5.6, 27.1, and 4.6%, respectively. All phenotypes were moderately to highly correlated. Genetic influences on self-injurious thoughts and behaviors and HRT were significant and highly correlated among men [rG = 0.59, 95% confidence interval (CI) (0.37–0.81)] and women [rG = 0.56 (0.49–0.63)]. Unique environmental influences were modestly correlated in women [rE = 0.23 (0.01–0.45)], suggesting that high-risk trauma may confer some direct risk for self-injurious thoughts and behaviors among females.
Individuals engaging in NSSI are at increased risk for suicide, and common heritable factors contribute to these associations. Preventing trauma exposure may help to mitigate risk for self-harm and suicide, either directly or indirectly via reductions in liability to psychopathology more broadly. In addition, targeting pre-existing vulnerability factors could significantly reduce risk for life-threatening behaviors among those who have experienced trauma.
To assess antimicrobial prescriber knowledge, attitudes, and practices (KAP) regarding antimicrobial stewardship (AS) and associated barriers to optimal prescribing.
A convenience sample of 2,900 US antimicrobial prescribers at 5 acute-care hospitals within a hospital network.
The following characteristics were assessed with an anonymous, online survey in February 2015: attitudes and practices related to antimicrobial resistance, AS programs, and institutional AS resources; antimicrobial prescribing and AS knowledge; and practices and confidence related to antimicrobial prescribing.
In total, 402 respondents completed the survey. Knowledge gaps were identified through case-based questions. Some respondents sometimes selected overly broad therapy for the susceptibilities given (29%) and some “usually” or “always” preferred using the most broad-spectrum empiric antimicrobials possible (32%). Nearly all (99%) reported reviewing antimicrobial appropriateness at 48–72 hours, but only 55% reported “always” doing so. Furthermore, 45% of respondents felt that they had not received adequate training regarding antimicrobial prescribing. Some respondents lacked confidence selecting empiric therapy using antibiograms (30%), interpreting susceptibility results (24%), de-escalating therapy (18%), and determining duration of therapy (31%). Postprescription review and feedback (PPRF) was the most commonly cited AS intervention (79%) with potential to improve patient care.
Barriers to appropriate antimicrobial selection and de-escalation of antimicrobial therapy were identified among front-line prescribers in acute-care hospitals. Prescribers desired more AS-related education and identified PPRF as the most helpful AS intervention to improve patient care. Educational interventions should be preceded by and tailored to local assessment of educational needs.
While our fascination with understanding the past is sufficient to warrant an increased focus on synthesis, solutions to important problems facing modern society require understandings based on data that only archaeology can provide. Yet, even as we use public monies to collect ever-greater amounts of data, modes of research that can stimulate emergent understandings of human behavior have lagged behind. Consequently, a substantial amount of archaeological inference remains at the level of the individual project. We can more effectively leverage these data and advance our understandings of the past in ways that contribute to solutions to contemporary problems if we adapt the model pioneered by the National Center for Ecological Analysis and Synthesis to foster synthetic collaborative research in archaeology. We propose the creation of the Coalition for Archaeological Synthesis coordinated through a U.S.-based National Center for Archaeological Synthesis. The coalition will be composed of established public and private organizations that provide essential scholarly, cultural heritage, computational, educational, and public engagement infrastructure. The center would seek and administer funding to support collaborative analysis and synthesis projects executed through coalition partners. This innovative structure will enable the discipline to address key challenges facing society through evidentially based, collaborative synthetic research.
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.
Measurements made by an underwater glider deployed near the Ross Ice Shelf were used to identify the presence of Ice Shelf Water (ISW), which is defined as seawater with its potential temperature lower than its surface freezing point temperature. Properties logged by the glider included in situ temperature, electrical conductivity, pressure, GPS location at surfacings and time. For most of the first 30 recorded dives of its deployment, evidence suggests the glider was prevented from surfacing due to being under the ice shelf. For dives under the ice shelf, farthest from the ice shelf front, ISW layers of varying thicknesses and depth locations were observed; between 2 m thick (centred at 231 m depth) to >93 m thick (centred at >360 m). For dives under the ice shelf, close to the ice shelf front, either no ISW was observed or ISW layers were centred at shallower depths (116–127 m). Thicker ISW layers (e.g. up to 250 m thickness centred at 421 m) were observed for some glider dives in open water in front of the Ross Ice Shelf. No in situ supercooling (water colder than the pressure-dependent freezing point temperature) was observed.
The effects of environmental factors such as water stress, elevated CO2, or temperature on carbon assimilation and allocation in plants have been studied extensively (Gifford and Evans, 1981; Loomis, Rabbinge, and Ng, 1979; Neales and Incoll, 1968). However, the interactions of these processes are not well understood and cannot be predicted with any degree of confidence. Continuous and simultaneous measurements of photosynthesis, transport, and sink activity have never been made during the short- and long-term responses of live, intact plants to step changes in environmental factors. Thus, direct environmental effects and adaptive responses of plants are generally not distinguished. This results in part from limitation in experimental techniques and protocol used in past studies and the lack of experimental validation of hypotheses and models (eg, Goeschl et al, 1976; Magnuson et al, 1979; Smith et al, 1970) dealing with these problems. This paper describes in detail the components of an integrated technique for studying carbon assimilation, transportation and allocation in intact live plants under any set of environmental conditions, using continuously produced 11CO2.
We present a survey of carbon beam yields from 20 simple carbon compounds using a caesium sputter source and the McMaster University tandem accelerator. The carbon yield was measured as a 35MeV 12C4+ beam. We found that the beam intensities could be related to a grouping of the carbides according to the chemical bonding of the compounds. The usefulness of the compounds for accelerator 14C dating was further related to their preparation chemistries. Strontium carbide was the equal of graphite in negative carbon ion beam production and aluminum carbide was found to be a good candidate for further tests because of its good sputter yield and preparation chemistry. Charcoal was also tested with varying amounts of silver added as a heat conduction aid.
A Tandem Van de Graaff accelerator has been modified for use in the direct measurement of natural abundances of 10Be and 14C. A description of the system is given and some 10Be results on oceanographic samples are discussed.
(Solar Phys.) When the Culgoora radioheliograph started operating at both 80 MHz (the initial frequency) and 160 MHz (from May 1972) it became possible for the first time to make simultaneous observations of the fundamental and second harmonic sources in type II bursts. Three such bursts, each having harmonically related split-bands, have been observed so far. The new 80 and 160 MHz heliograph observations are illustrated in Figure 1. Since all three events had split-band structure the results are presented separately for the lower- (l) and upper- (u) frequency components and differences between the source positions in the two components will be highlighted. For the burst of 1973 May 19, which was observed at large zenith angles, calculated corrections for ionospheric refraction – approximately 1′ to 2′ for the 80 MHz sources – have been applied; the remaining two events are presented as observed since the refraction effects are thought to be small.
On 1975 August 22 an outburst above the west limb of the Sun was observed with the Culgoora radioheliograph at 43, 80 and 160 MHz. The first stages of the event included intense type III/V bursts followed by a type II burst with multiple, fundamental and harmonic bands and herringbone structure. While the type II burst was still in progress a moving type IV burst appeared. It was eventually observed out to a distance of more than 3 R⊙. This was the first moving type IV burst observed with the two-dimensional radioheliograph operating at three frequencies; as such it provides valuable constraints on models of moving type IV sources.
Crannell et al. (1978) have reported an observed correlation between the time profiles and flux densities of impulsive hard X-ray and microwave solar bursts. We report here on a significant correlation between the flux density of extended bursts of hard X-rays and micowaves. These extended events follow after impulsive bursts and last much longer (see e.g. Fig. 1, Frost and Dennis 1971). However, as extended bursts only occur during very large flares the number of cases available for study is small. The significance of our observations follows from the suggestion of Wild et al. (1963) that the extended bursts are evidence for a second-phase acceleration process in the corona. We show that the observed characteristics of these extended microwave bursts (viz. a rather flat spectrum below a turnover frequency which is independent of intensity) can be explained by gyro-synchrotron radiation from the same population of energetic (E ≈ 100 keV) electrons as those emitting (thin-target) X-ray bremsstrahlung. A detailed source model is discussed in a companion paper (Nelson and Stewart 1979 — Paper B).
We present an overview of the survey for radio emission from active stars that has been in progress for the last six years using the observatories at Fleurs, Molonglo, Parkes and Tidbinbilla. The role of complementary optical observations at the Anglo-Australian Observatory, Mount Burnett, Mount Stromlo and Siding Spring Observatories and Mount Tamborine are also outlined. We describe the different types of star that have been included in our survey and discuss some of the problems in making the radio observations.
Although only three antennas of the Australia Telescope Compact Array are currently operational, we have made use of the technique of bandwidth synthesis to make an image of the radio galaxy 2152 – 69. The three baselines were used to observe the source at three different frequencies, effectively resulting in nine baselines, which have been used to produce an image with a surprisingly high dynamic range, and with a slightly higher resolution than any existing image.
The production of such a worthwhile result, despite being made with a small subset of the capabilities of the Australia Telescope, bodes well for the future operation of the instrument.
In a previous paper of this issue (Stewart and Nelson 1979 — Paper A) we showed that for extended bursts a good correlation exists between the observed 100 keV X-ray slux density and the 3.75 or 9.4 GHz microwave flux density. We also showed that the microwave spectrum of these bursts was much flatter (S ∝ f1.0 on the average) than the optically thick (self-absorbed) spectrum observed for impulsive microwave bursts (Crannell et al. 1978; Dulk et al. 1978). Furthermore, the microwave turnover frequency was > 10 GHz in eight of the nine events studied and <20 GHz in four of these cases. The remaining event, which was severely occulted by the solar limb, had a turnover frequency of ∽ 1 GHz.
The single G8V active chromosphere star HD36705 (AB Dor) was observed at 8.4 GHz with the Parkes 64 m telescope during three observing sessions involving a total of 21 days in the interval 1985 December to 1986 February. Subsequent photometric observations were made of the star with the 0.25 m and 0.45 m telescopes of the Monash Observatory in 1986 March-April. Two strong radio flares, each lasting three days, were detected; they yielded peak radio powers of P8.4≈4×109 W Hz-1, comparable with the microwave power emitted by the RS CVn binaries. Significant circular polarization of 13% left-hand was measured on only one of the six active days. The 8.4 GHz flux density showed smooth variation over an interval of several hours, consistent with the flare source being partly occulted by the stellar disk as the star rotated. When all the radio data was phase-binned using the known rotation period of 0.514 day we found two radio maxima corresponding to radio sources at stellar longitudes ~180° apart. The subsequent photometric data showed intensity variations that were consistent with the starspots at the same approximate longitudes. We thus interpret our radio curve as showing the presence of comparatively small (<0.5 D*) radio sources in the corona above the star spots. The upper limit to source diameter gives a peak brightness temperature ≥2×l010 K, which can be achieved by gyro-synchrotron emission only if the source is optically thick and the electrons, with average energy ~ 2 MeV, have a hard energy spectrum. The observed radiation can be due only to very high harmonics of the gyro-frequency, leading to an estimate for the magnetic field strength of ~30G.
Recently a programme of observing 21 cm-λ solar radio bursts with high angular resolution has been commenced at the Fleurs Radio Field Station of the School of Electrical Engineering, University of Sydney. In some preliminary measurements fringes from two 2-element E-W interferometers, spaced at roughly 3800 and 1900 wavelengths, have been recorded simultaneously.