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We describe 14 yr of public data from the Parkes Pulsar Timing Array (PPTA), an ongoing project that is producing precise measurements of pulse times of arrival from 26 millisecond pulsars using the 64-m Parkes radio telescope with a cadence of approximately 3 weeks in three observing bands. A comprehensive description of the pulsar observing systems employed at the telescope since 2004 is provided, including the calibration methodology and an analysis of the stability of system components. We attempt to provide full accounting of the reduction from the raw measured Stokes parameters to pulse times of arrival to aid third parties in reproducing our results. This conversion is encapsulated in a processing pipeline designed to track provenance. Our data products include pulse times of arrival for each of the pulsars along with an initial set of pulsar parameters and noise models. The calibrated pulse profiles and timing template profiles are also available. These data represent almost 21 000 h of recorded data spanning over 14 yr. After accounting for processes that induce time-correlated noise, 22 of the pulsars have weighted root-mean-square timing residuals of
in at least one radio band. The data should allow end users to quickly undertake their own gravitational wave analyses, for example, without having to understand the intricacies of pulsar polarisation calibration or attain a mastery of radio frequency interference mitigation as is required when analysing raw data files.
Oxidative stress is implicated in the aetiology of schizophrenia, and the antioxidant defence system (AODS) may be protective in this illness. We examined the major antioxidant glutathione (GSH) in prefrontal brain and its correlates with clinical and demographic variables in schizophrenia.
GSH levels were measured in the dorsolateral prefrontal region of 28 patients with chronic schizophrenia using a magnetic resonance spectroscopy sequence specifically adapted for GSH. We examined correlations of GSH levels with age, age at onset of illness, duration of illness, and clinical symptoms.
We found a negative correlation between GSH levels and age at onset (r = −0.46, p = 0.015), and a trend-level positive relationship between GSH and duration of illness (r = 0.34, p = 0.076).
Our findings are consistent with a possible compensatory upregulation of the AODS with longer duration of illness and suggest that the AODS may play a role in schizophrenia.
Apolipoprotein E (APOE) E4 is the main genetic risk factor for Alzheimer’s disease (AD). Due to the consistent association, there is interest as to whether E4 influences the risk of other neurodegenerative diseases. Further, there is a constant search for other genetic biomarkers contributing to these phenotypes, such as microtubule-associated protein tau (MAPT) haplotypes. Here, participants from the Ontario Neurodegenerative Disease Research Initiative were genotyped to investigate whether the APOE E4 allele or MAPT H1 haplotype are associated with five neurodegenerative diseases: (1) AD and mild cognitive impairment (MCI), (2) amyotrophic lateral sclerosis, (3) frontotemporal dementia (FTD), (4) Parkinson’s disease, and (5) vascular cognitive impairment.
Genotypes were defined for their respective APOE allele and MAPT haplotype calls for each participant, and logistic regression analyses were performed to identify the associations with the presentations of neurodegenerative diseases.
Our work confirmed the association of the E4 allele with a dose-dependent increased presentation of AD, and an association between the E4 allele alone and MCI; however, the other four diseases were not associated with E4. Further, the APOE E2 allele was associated with decreased presentation of both AD and MCI. No associations were identified between MAPT haplotype and the neurodegenerative disease cohorts; but following subtyping of the FTD cohort, the H1 haplotype was significantly associated with progressive supranuclear palsy.
This is the first study to concurrently analyze the association of APOE isoforms and MAPT haplotypes with five neurodegenerative diseases using consistent enrollment criteria and broad phenotypic analysis.
Laser–solid interactions are highly suited as a potential source of high energy X-rays for nondestructive imaging. A bright, energetic X-ray pulse can be driven from a small source, making it ideal for high resolution X-ray radiography. By limiting the lateral dimensions of the target we are able to confine the region over which X-rays are produced, enabling imaging with enhanced resolution and contrast. Using constrained targets we demonstrate experimentally a
X-ray source, improving the image quality compared to unconstrained foil targets. Modelling demonstrates that a larger sheath field envelope around the perimeter of the constrained targets increases the proportion of electron current that recirculates through the target, driving a brighter source of X-rays.
Magnetic skyrmions are particle-like, topologically protected magnetization entities that are promising candidates for information carriers in racetrack-memory schemes. The transport of skyrmions in a shift-register-like fashion is crucial for their embodiment in practical devices. Recently, we demonstrated experimentally that chiral skyrmions in Cu2OSeO3 can be effectively manipulated by a magnetic field gradient, leading to a collective rotation of the skyrmion lattice with well-defined dynamics in a radial field gradient. Here, we employ a skyrmion particle model to numerically study the effects of resultant shear forces on the structure of the skyrmion lattice. We demonstrate that anisotropic peak broadening in experimentally observed diffraction patterns can be attributed to extended linear regions in the magnetic field profile. We show that topological (5-7) defects emerge to protect the six-fold symmetry of the lattice under the application of local shear forces, further enhancing the stability of proposed magnetic field driven devices.
OBJECTIVES/SPECIFIC AIMS: The aim of this study was to assess the ultra-dose Na18F dPET protocol feasibility for skeleton imaging in a canine model with reduced radiation dose and preserved quantitative characteristics. We hypothesized that administering an ultra-low Na18F dose would provide suitable image quality while reducing subject’s exposure to radiation. METHODS/STUDY POPULATION: In total, 13 adult male beagles [weight (kg) mean±SD; 14.3±2.2] were scanned. The dogs were administered 3 different Na18F doses: 3 (standard dose/SD), 1 (low dose/LD), and 0.05 (ultra-low dose/ULD) mCi. Imaging started ≃45 minutes post injection for ≃ 33 minute total acquisition time. Covering the whole body, 11 bed positions, acquiring 120 (3 mCi) and 180 (1, 0.05 mCi) seconds per bed position. All imaging was performed on a digital photon counting system (Philips Vereos, pre-commercial release). PET list mode data were reconstructed using Time-of-flight with 4, 2, and 1 mm3 voxel volumes. Point spread function, and Gaussian filtering were applied. Two experienced blinded readers evaluated image sets overall quality, tissue characterization, and quality of background in the whole body skeleton. Three-dimensional (3D) regions of interest (ROI) were traced over the distal femur, first lumbar vertebra, and a portion of the liver, recording standard uptake values (SUVmax and SUVmean). RESULTS/ANTICIPATED RESULTS: All the scans and reconstructions were successfully completed in all subjects. Decreasing Na18F dose from the standard dose (3 mCi) to the ultra-low dose/ULDO (0.05 mCi), demonstrated acceptable image quality and quantification. Ultra-low dose Na18F SUVmean values for the 3D ROIs reported (mean±SD) 2.6±0.7, 2.5±1.1, 9±1.6, and 0.6±0.3 from the right and left distal femur, first lumbar vertebra, and a portion of the liver, respectively. When compared the SD with the LD and ULD, dPET demonstrated acceptable image quality and definition for qualitative overall assessment. This was also found for the overall quantitative ROI assessment of the healthy canine skeletons. DISCUSSION/SIGNIFICANCE OF IMPACT: Ultra-low dose Na18F at a level of 50 μCi for a 14 kg canine appears to be diagnostically feasible and a robust option to reduce (60-fold) radiotracer doses in a translational animal model using a dPET system. Furthermore, it allows us to move preclinical nuclear medicine imaging forward with substantial reduced exposure levels while preserving image quality. Both visual and quantitative results indicate that the standard-dose bone Na18F dPET can be decreased with a satisfactory diagnostic image quality. Ultra-low Na18F dose is indeed important for younger populations, control patients, and nononcological diseases/conditions. Favorable pharmacokinetics of Na18F (such as high bone uptake, minimal binding to serum proteins, rapid single-pass extraction, and fast clearance from the soft tissues) in addition to the technological capabilities of dPET/CT demonstrated feasibility enabling dose reduction strategies. Ultra-low dose has diagnostic reproducibility and lower radiation burden compared with higher fixed dose techniques in current available guidelines [Society of Nuclear Medicine and Molecular Imaging; SNMMI (5–10 mCi)]. Na18F dPET/CT provides higher sensitivity and diagnostic accuracy, which enables high-quality images with lower tracer activity in this translational animal model. Future research will apply the same methodology to other anatomical targets as well as to the use of different tracers. Preclinical nuclear medicine imaging using ultra-low tracer doses, demonstrated the potential to obtain reasonable quality images and diminishing radiation surveillance in accordance with as low as reasonably achievable tracer levels.
Integration of the III–V material systems on Si is an enabling technology for achieving high efficiency heterojunction Si-based photovoltaic devices. Gallium phosphide (GaP) offers numerous potential electrical, optical, and material advantages over amorphous silicon (a-Si) for the realization of several heterojunction solar cell designs. In this paper, details are given for the growth, fabrication, and characterization of different n-GaP/n-Si heterojunction solar cells to explore the effect of GaP as a carrier-selective contact. The cell performance is promising with high Si bulk lifetime (∼2.2 ms at the injection level of 1015 cm−3) and an open-circuit voltage of 618 mV and an efficiency of 13.1% in this new solar cell design. In addition to GaP as an electron-selective contact, MoOx was successfully implemented as a hole-selective contact in the n-GaP/n-Si heterojunction solar cell, increasing efficiency to 14.1% by improving the short wavelength response. The Si bulk lifetime is maintained during growth of GaP on Si by two different approaches and their effects on GaP/Si solar cell performance are also presented.
Across the globe, the implementation of quality improvement science and collaborative learning has positively affected the care and outcomes for children born with CHD. These efforts have advanced the collective expertise and performance of inter-professional healthcare teams. In this review, we highlight selected quality improvement initiatives and strategies impacting the field of cardiovascular care and describe implications for future practice and research. The continued leveraging of technology, commitment to data transparency, focus on team-based practice, and recognition of cultural norms and preferences ensure the success of sustainable models of global collaboration.
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 Yellow Sea region is of high global importance for waterbird populations, but recent systematic bird count data enabling identification of the most important sites are relatively sparse for some areas. Surveys of waterbirds at three sites on the coast of southern Jiangsu Province, China, in 2014 and 2015 produced peak counts of international importance for 24 species, including seven globally threatened and six Near Threatened species. The area is of particular global importance for the ‘Critically Endangered’ Spoon-billed Sandpiper Calidris pygmaea (peak count across all three study sites: 62 in spring  and 225 in autumn  and ‘Endangered’ Spotted Greenshank Tringa guttifer (peak count across all three study sites: 210 in spring  and 1,110 in autumn ). The southern Jiangsu coast is therefore currently the most important migratory stopover area in the world, in both spring and autumn, for both species. Several serious and acute threats to waterbirds were recorded at these study sites. Paramount is the threat of large-scale land claim which would completely destroy intertidal mudflats of critical importance to waterbirds. Degradation of intertidal mudflat habitats through the spread of invasive Spartina, and mortality of waterbirds by entrapment in nets or deliberate poisoning are also real and present serious threats here. Collisions with, and displacement by, wind turbines and other structures, and industrial chemical pollution may represent additional potential threats. We recommend the rapid establishment of effective protected areas for waterbirds in the study area, maintaining large areas of open intertidal mudflat, and the urgent removal of all serious threats currently faced by waterbirds here.
This paper presents the first major data release and survey description for the ANU WiFeS SuperNovA Programme. ANU WiFeS SuperNovA Programme is an ongoing supernova spectroscopy campaign utilising the Wide Field Spectrograph on the Australian National University 2.3-m telescope. The first and primary data release of this programme (AWSNAP-DR1) releases 357 spectra of 175 unique objects collected over 82 equivalent full nights of observing from 2012 July to 2015 August. These spectra have been made publicly available via the WISEREP supernova spectroscopy repository.
We analyse the ANU WiFeS SuperNovA Programme sample of Type Ia supernova spectra, including measurements of narrow sodium absorption features afforded by the high spectral resolution of the Wide Field Spectrograph instrument. In some cases, we were able to use the integral-field nature of the Wide Field Spectrograph instrument to measure the rotation velocity of the SN host galaxy near the SN location in order to obtain precision sodium absorption velocities. We also present an extensive time series of SN 2012dn, including a near-nebular spectrum which both confirms its ‘super-Chandrasekhar’ status and enables measurement of the sub-solar host metallicity at the SN site.
We present two isotopic (δ18O and δ13C) sequences of a twin-stalagmite from Zhuliuping Cave, southwestern China, with 230Th dates from 14.6 to 4.6 ka. The stalagmite δ18O record characterizes orbital- to decadal-scale variability of Asian summer monsoon (ASM) intensity, with the Holocene optimum period (HOP) between 9.8 and 6.8 ka BP which is reinforced by its co-varying δ13C data. The large multi-decadal scale amplitude of the cave δ18O indicates its high sensitivity to climate change. Four centennial-scale weak ASM events during the early Holocene are centered at 11.2, 10.8, 9.1 and 8.2 ka. They can be correlated to cold periods in the northern high latitudes, possibly resulting from rapid dynamics of atmospheric circulation associated with North Atlantic cooling. The 8.2 ka event has an amplitude more than two-thirds that of the Younger Dryas (YD), and is significantly stronger than other cave records in the Asia monsoon region, likely indicating a more severe dry climate condition at the cave site. At the end of the YD event, the δ13C record lags the δ18O record by 300–500 yr, suggesting a multi-centennial slow response of vegetation and soil processes to monsoon enhancement.
The Nihewan Basin is a key region for studying the Palaeolithic archaeology of East Asia. However, because of the lack of suitable dating methods and representative lithic technologies in this region, the ‘Middle Palaeolithic’ sites in this basin have been designated based mainly on stratigraphic correlation, which may be unreliable. In this study, three Palaeolithic sites, Motianling, Queergou and Banjingzi, which have been assigned previously to the ‘Middle Palaeolithic’, are dated based on luminescence dating of K-feldspar grains. Our results show that the cultural layers at Motianling, Queergou and Banjingzi have ages of 315 ± 13, 268 ± 13 and 86 ± 4 ka (corresponding to Marine Isotope Stages 9, 8 and 5), respectively, suggesting that Motianling and Queergou should be assigned to the Lower Palaeolithic, while the age of Banjingzi is consistent with a Middle Palaeolithic attribution. Our results suggest that reassessing the age of ‘Middle Palaeolithic’ sites in the Nihewan Basin, and elsewhere in North China, is crucial for understanding the presence or absence of the Middle Palaeolithic phase in China. Our dating results also indicate that the Sanggan River developed sometime between about 270 and 86 ka ago.
Identification of individuals within pairs of monozygotic (MZ) twins remains unresolved using common forensic DNA typing technology. For some criminal cases involving MZ twins as suspects, the twins had to be released due to inability to identify which of the pair was the perpetrator. In this study, we performed a genome-wide scan on whole blood-derived DNA from four pairs of healthy phenotypically concordant MZ twins using the methylated DNA immunoprecipitation sequencing technology to identify candidate DNA methylation markers with capacity to distinguish MZ twins within a pair. We identified 38 differential methylation regions showing within-pair methylation differences in all four MZ pairs. These are all located in CpG islands, 17 of which are promoter-associated, 17 are intergenic islands, and four are intragenic islands. Genes associated with these markers are related with cell proliferation, differentiation, and growth and development, including zinc finger proteins, PRRX2, RBBP9, or are involved in G-protein signaling, such as the regulator of G-protein signaling 16. Further validation studies on additional MZ twins are now required to evaluate the broader utility of these 38 markers for forensic use.
Phase-change materials (PCMs) are promising candidates for novel data-storage and memory applications. They encode digital information by exploiting the optical and electronic contrast between amorphous and crystalline states. Rapid and reversible switching between the two states can be induced by voltage or laser pulses. Here, we review how density-functional theory (DFT) is advancing our understanding of PCMs. We describe key DFT insights into structural, electronic, and bonding properties of PCMs and into technologically relevant processes such as fast crystallization and relaxation of the amorphous state. We also comment on the leading role played by predictive DFT simulations in new potential applications of PCMs, including topological properties, switching between different topological states, and magnetic properties of doped PCMs. Such DFT-based approaches are also projected to be powerful in guiding advances in other materials-science fields.
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 NASA Kepler satellite has provided unprecedented high duty-cycle, high-precision light curves for a large number of stars by continuously monitoring a field of view in Cygnus-Lyra region, leading to great progress in both discovering exoplanets and characterizing planet-hosting stars by means of asteroseismic methods. The asteroseismic survey allows the investigation of stars covering the whole H-R diagram. However, the low precision of effective temperatures and surface gravities in the KIC catalogue and the lack of information on chemical composition, metallicity and rotation rate prevent asteroseismic modeling, requiring spectroscopic observations for thousands of asteroseismic targets in the Kepler field in a homogeneous way.
At the 2012 General Assembly of the International Astronomical Union (IAU), the Office of Astronomy for Development announced a number of exciting new partnerships to assist with the IAU's decadal strategic plan (2010--2020). These landmark decisions included establishing a new coordinating centre that aims at using astronomy as a tool for development in East Asia. The agreement covers two important functions. One is known as a Regional Node, which entails the coordination of astronomy-for-development activities in countries within the general geographical region of East Asia. The other is known as a Language Expertise Centre which deals with all aspects relating to (mainly) the Chinese language and culture. The impact of the latter may obviously spread well beyond the geographical region to other parts of the world. Here we provide an update of the achievements and aims of the East Asian Office of Astronomy for Development.
Time is an essential element of fundamental astronomy. In recent years there have been many time-related issues, in scientific and technological aspects as well as in conventions and definitions. At the Commission 31 (Time) business meeting at the XXIX General Assembly, recent progress and many topics, including Pulsar Time Scales WG and Future UTC WG activities, were reviewed and discussed. In this report, we will review the progress of these topics in the past three years. There are many remarkable topics, such as Time scales, Atomic clock development, Time transfer, Future UTC and future redefinition of the second. Among them, scientific highlights are the progress of pulsar time scales and the optical frequency standards. On the other hand, as the social convention, change in the definition of UTC and the second is important.
To date, most antibodies from combinatorial libraries have been selected purely on the basis of binding. However, new methods now allow selection on the basis of function in animal cells. These selected agonist antibodies have given new insights into the important problem of signal transduction. Remarkably, when some antibodies bind to a given receptor they induce a cell fate that is different than that induced by the natural agonist to the same receptor. The fact that receptors can be functionally pleiotropic may yield new insights into the important problem of signal transduction.