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We define a measure for the accuracy of tomographic reconstruction in atom probe tomography, named here the spatial error index. We demonstrate that this index can be used to compare rigorously the spatial accuracy of various different approaches to the calculation of tomographic reconstruction. This is useful, for example, to evaluate the performance of alternate tomographic reconstruction approaches, and ensures that the comparisons are independent of individual data quality or other instrumental parameters. We then introduce a new “adaptive reconstruction” formalism that uses a progression of reconstruction parameters based on a per-atom correction from the cube root of the inverse of the voltage, along with linear correction factors linked to the evaporation sequence. We apply the measure for spatial accuracy to this new reconstruction protocol.
Current approaches to reconstruction in atom probe tomography produce results that exhibit substantial distortions throughout the analysis depth. This is largely because of the need to apply a multitude of assumptions when estimating the evolution of the tip shape, and other pseudo-empirical reconstruction factors, which vary both across the face of the tip and throughout the analysis depth. We introduce a new crystallography-mediated reconstruction to improve the spatial accuracy and dramatically reduce these in-depth variations. To achieve this, we developed a barycentric transform to directly relate atomic positions in detector space to real space. This is mediated by novel crystallographic analysis techniques, including: (1) calculating the orientation of a crystal directly from the field evaporation map, (2) tracking pole locations throughout the evaporation sequence, and (3) accounting for the evolving tip radius in a manner that removes the dependence on the geometric field factor. By improving the in-depth spatial accuracy of the atom probe reconstruction, a greater accuracy of the atomic neighborhood relationships is available. This is critical in modern materials science and engineering, where an understanding of the solid solution architecture, precipitate dispersions, and descriptions of the interfaces between phases or grains are key inputs to microstructure–property relationships.
It is known that if rats learn that a cue reliably precedes eating, its presentation can cause them to initiate a feeding bout when they are apparently sated (Weingarten, 1983, 1985). However, it is currently unclear precisely how such conditioned cues affect appetite. For example, does this type of conditioning elicit food specific appetites or do individuals merely experience a general increase in feeding motivation (Mela & Rogers, 1998)? To address this issue, the present experiment investigated the hypothesis that exposure to a cue (conditioned stimulus: CS) previously paired with a specific food biases diet selection in favour of that food when an individual is given a choice. The objective of the experiment was to enhance our understanding of the behavioural control of feeding, and hence our ability to predict diet selection and food intake.
The experimental subjects were 12 male Lister-hooded rats (initial body-weight 233; SD=20g). Throughout the experiment the subjects were maintained on a 1lh:13h light:dark cycle with lights on at 0700h, and had ad libitum access to a standard laboratory diet during the light phase.
A 36C1 peak has been found at about 37 ka BP in the Guliya ice core, drilled from the Qinghai-Tibetan Plateau. This peak is indicative of enhanced cosmogenic isotope production in the atmosphere, rather than a change in accumulation rate. Comparison with the records of 10Be and 36C1 in ice cores from Antarctica and Greenland indicates that peaks of the cosmogenic isotopes are global, and that they can be used as time markers for dating ice cores. Interestingly, the 37 ka BP global event coincided with a cold period.
Methanesulfonate was investigated as a potential contributor to the sulfur budget, based on analysis of a firn core from Collins Ice Cap, King George Island, Antarctica (62°10′ S, 58°50′ W). The anion was found to be present at a mean concentration of 0.17 μeq L−1, with a maximum of 0.73 μeq L−1. Dating based on the δ18O profile suggests that the principal peaks of methanesulfonate are associated with snow deposited in summer and autumn. A careful examination of MSA, SO42− and nssSO42− profiles indicates that two of the three peaks in the MSA profile may result mainly from migration and relocation of MSA. The mechanism responsible for this might be similar to that for deep cores from other Antarctic glaciers, supporting the migration hypothesis proposed by prior researchers and extending it to near-temperate ice. Due to the post-depositional modification, the main part of the MSA profile of the firn is no longer indicative of the seasonal pattern of MSA in the atmosphere, and the basis for calculation of the MSA/nssSO42− ratio should be changed. The MSA/nssS042 ratio obtained by a new computation is 0.22, 10% higher than that ignoring the effect of MSA migration.
Radio continuum surveys are equally sensitive to all pulsars, not affected by dispersion measure smearing, scattering or orbital modulation of spin periods, and therefore allow us to search for extreme pulsars, such as sub-millisecond pulsars, pulsar-black hole systems and pulsars in the Galactic Centre. As we move towards the Square Kilometre Array (SKA) era, searching for pulsars in continuum images will complement conventional pulsar searches, and make it possible to find extreme objects.
Coastal ecosystems are particularly vulnerable to alien invasions. Regular, standardized, targeted monitoring of coastal areas helps to detect the arrival of non-native species early, identify sites most vulnerable to invasion, and assess potential for further spread. This study quantified the spread and changes in distribution of non-native oyster, Crassostrea gigas, populations around the coast of Ireland. In total 37 sites were surveyed, in areas which either currently or previously harboured cultivated C. gigas, for the presence and abundance of ‘wild’ C. gigas. Wild populations were identified at 20 sites and at four additional sites C. gigas was observed as recently discarded from aquaculture activity. Five of the invaded sites were identified as being highly suitable for a population expansion based on their current population status. Importantly, we also identified individuals of C. gigas and native European oysters, Ostrea edulis, co-occurring within the same shore at five sites. This is the first record to our knowledge of such co-occurrence within Europe. This evidence of co-existing oyster species raises concerns regarding the potential impact of C. gigas on recovering O. edulis populations. In Ireland, however, C. gigas does not typically spread extensively from introduction points, and although self-containing populations exist, they are currently sustained at a much lower density than those observed in other regions such as the Wadden Sea or French Atlantic coasts. We suggest, therefore, that to protect native oyster populations, C. gigas should be eradicated where co-occurring with O. edulis and recommend continuous monitoring of invaded sites.
During 2016 February, CSIRO Astronomy and Space Science and the Max-Planck-Institute for Radio Astronomy installed, commissioned, and carried out science observations with a phased array feed receiver system on the 64-m diameter Parkes radio telescope. Here, we demonstrate that the phased array feed can be used for pulsar observations and we highlight some unique capabilities. We demonstrate that the pulse profiles obtained using the phased array feed can be calibrated and that multiple pulsars can be simultaneously observed. Significantly, we find that an intrinsic polarisation leakage of −31 dB can be achieved with a phased array feed beam offset from the centre of the field of view. We discuss the possibilities for using a phased array feed for future pulsar observations and for searching for fast radio bursts with the Parkes and Effelsberg telescopes.
Correlative microscopy approaches offer synergistic solutions to many research problems. One such combination, that has been studied in limited detail, is the use of atom probe tomography (APT) and transmission Kikuchi diffraction (TKD) on the same tip specimen. By combining these two powerful microscopy techniques, the microstructure of important engineering alloys can be studied in greater detail. For the first time, the accuracy of crystallographic measurements made using APT will be independently verified using TKD. Experimental data from two atom probe tips, one a nanocrystalline Al–0.5Ag alloy specimen collected on a straight flight-path atom probe and the other a high purity Mo specimen collected on a reflectron-fitted instrument, will be compared. We find that the average minimum misorientation angle, calculated from calibrated atom probe reconstructions with two different pole combinations, deviate 0.7° and 1.4°, respectively, from the TKD results. The type of atom probe and experimental conditions appear to have some impact on this accuracy and the reconstruction and measurement procedures are likely to contribute further to degradation in angular resolution. The challenges and implications of this correlative approach will also be discussed.
Ice cores recently drilled to bedrock on the col of Huascarán (9°06′ S, 77°36′ W, 6047 m a.s.l.) offer the potential for a long, annually resolved climate record from tropical South America. This paper presents the record from 1950 to 1993 preserved in microparticle and nitrate concentrations and oxygen-isotopic ratios. Average monthly temperatures from a satellite-linked automatic weather station installed on nearby Hualcán in 1991 are presented. Annual temperatures from local high-altitude meteorological stations, along with the annual Huascarán isotopic record, show a warming trend over the last two decades. The marked preservation of the climate record in oxygen-isotopic ratios on Huascarán is absent at lower-elevation sites, which have been affected by the recent warming. This paper demonstrates the establishment of a time-scale for the Huascarán core, the preservation of the climatic signal with depth and the linkage of the ice-core “proxy-climate” parameters with measured climatic variations.
The quality and utility of the records of oxygen-isotopic abundances, dust concentrations and anionic concentrations preserved in the ice at Siple Station (75°55′ S, 84° 15′ W) are assessed from four shallow (20 m) cores. The combination of high accumulation (0.56 m a−1 w.e.) and low mean annual temperature (—24°C) preserves the prominent seasonal variations in δ18Ο which are very spatially coherent. Sulfate concentrations vary seasonally and, in conjunction with δ18Ο, will allow accurate dating of deeper cores from Siple Station. The concentrations of insoluble dust are the lowest measured in Antarctica, making Siple Station an excellent location to examine large increases in atmospheric tubidity.
The seasonal variations and annual fluxes of the anions are examined for the last two decades (AD 1966–85) with regard to probable sources. An unusually high sulfate flux in 1976 may reflect the February 1975 eruption of Mount Ngauruhoe, New Zealand. No annual signal in nitrate concentration is confirmed and no unusually high nitrate fluxes support the suggestion of nitrate production by large solar flares. However, nitrate flux is higher for the latter half of the 1970s and early 1980s, possibly reflecting the recent loss of stratospheric ozone.
Finally, comparison of the δ18O record with available surface-temperature data (AD 1957–85) reveals that multi-year trends along the western coast of the Antarctic Peninsula are recorded at Siple. More importantly, comparison with areally weighted temperature reconstructions suggests that the δ18Ο record may reflect larger-scale, persistent trends in the high southern latitudes. The strong spatial coherence of the preserved records, the potential for accurate dating, and possible relevance to larger-scale processes make Siple Station an excellent site for paleoenvironmental reconstruction from ice cores.
A truthful snapshot of horse welfare conditions is a prerequisite for predicting the impact of any actions intended to improve the quality of life of horses. This can be achieved when welfare information, gathered by different assessors in diverse geographical areas, is valid, comparable and collected in a harmonized way. This paper aims to present the first outcomes of the Animal Welfare Indicators (AWIN) approach: the results of on-farm assessment and a reliable and harmonized data collection system. A total of 355 sport and leisure horses, stabled in 40 facilities in Italy and in Germany, were evaluated by three trained assessors using the AWIN welfare assessment protocol for horses. The AWINHorse app was used to collect, store and send data to a common server. Identified welfare issues were obesity, unsatisfactory box dimensions, long periods of confinement and lack of social interaction. The digitalized data collection was feasible in an on-farm environment, and our results suggest that this approach could prove useful in identifying the most relevant welfare issues of horses in Europe or worldwide.
Background: Ataluren is the first drug to treat the underlying cause of nmDMD. Methods: Phase 2 and 3 studies of ataluren in nmDMD were reviewed, with efficacy and safety/tolerability findings summarized. Results: Ataluren nmDMD trials include: a Phase 2a proof-of-concept study (N=38); a Phase 2b randomized controlled trial (RCT) (N=174); an ongoing US-based open-label safety extension study (N=108); an ongoing non-US-based open-label safety/efficacy extension study (N=94); and a Phase 3 RCT, ACT DMD (N=228), whose primary endpoint was change in six-minute walk distance (6MWD) over 48 weeks. The proof-of-concept study demonstrated increased dystrophin production in post-treatment muscle biopsies from ataluren-treated patients with nmDMD. The Phase 2b results demonstrated an ataluren treatment effect in 6MWD, timed function tests, and other measures of physical functioning, The Phase 3 ACT DMD results demonstrated an ataluren treatment effect in patients with nmDMD in both primary and secondary endpoints, particularly in those with a baseline 6MWD of 300-400m. Ataluren was consistently well-tolerated in all three trials, as well as in the ongoing extension studies. Trial findings will be presented in detail. Conclusions: The totality of the results demonstrates that ataluren enables nonsense mutation readthrough in the dystrophin mRNA, producing functional dystrophin and slowing disease progression.
The Perth Astronomy Research Group (PARG), consisting of members from Curtin University of Technology, Perth Observatory and the University of Western Australia, is in the process of developing an automated supernova search system, using the 61-cm Lowell-Perth reflector, a CCD camera and an 80386-based computer for image analysis. Computer control of the telescope and dome, a liquid-nitrogen-cooled CCD camera, and modified VISTA image analysis software will be completed in late 1990, allowing initial semi-automatic searching of external galaxies, together with CCD photometry of flare stars and newly discovered supernovae. Full-scale automation will be introduced subsequently, in collaboration with the Berkeley group. This paper describes the project, and reports on its current status.
Both maternal 25-hydroxyvitamin D (25(OH)D) concentrations during pregnancy and
placental amino acid transporter gene expression have been associated with
development of the offspring in terms of body composition and bone structure.
Several amino acid transporter genes have vitamin D response elements in their
promoters suggesting the possible linkage of these two mechanisms. We aimed to
establish whether maternal 25(OH)D and vitamin D-binding protein (VDBP) levels
relate to expression of placental amino acid transporters. RNA was extracted
from 102 placental samples collected in the Southampton Women's Survey,
and gene expression was analysed using quantitative real-time PCR. Gene
expression data were normalised to the geometric mean of three housekeeping
genes, and related to maternal factors and childhood body composition. Maternal
serum 25(OH)D and VDBP levels were measured by radioimmunoassay. Maternal
25(OH)D and VDBP levels were positively associated with placental expression of
specific genes involved in amino acid transport. Maternal 25(OH)D and VDBP
concentrations were correlated with the expression of specific placental amino
acid transporters, and thus may be involved in the regulation of amino acid
transfer to the fetus. The positive correlation of VDBP levels and placental
transporter expression suggests that delivery of vitamin D to the placenta may
be important. This exploratory study identifies placental amino acid
transporters which may be altered in response to modifiable maternal factors and
provides a basis for further studies.
Various environmental factors have been associated with the timing of eruption of primary dentition, but the evidence to date comes from small studies with limited information on potential risk factors. We aimed to investigate associations between tooth emergence patterns and pre-conception, pregnancy and postnatal influences. Dentition patterns were recorded at ages 1 and 2 years in 2915 children born to women in the Southampton Women’s Survey from whom information had been collected on maternal factors before conception and during pregnancy. In mutually adjusted regression models we found that: children were more dentally advanced at ages 1 and 2 years if their mothers had smoked during pregnancy or they were longer at birth; mothers of children whose dental development was advanced at age 2 years tended to have poorer socioeconomic circumstances, and to have reported a slower walking speed pre-pregnancy; and children of mothers of Asian ethnicity had later tooth development than those of white mothers. The findings add to the evidence of environmental impacts on the timing of the eruption of primary dentition in indicating that maternal smoking during pregnancy, socio-economic status and physical activity (assessed by reported walking speed) may influence the child’s primary dentition. Early life factors, including size at birth are also associated with dentition patterns, as is maternal ethnicity.
We studied the temporal and spatial patterns of leptospirosis, its association with flooding and animal census data in Thailand. Flood data from 2010 to 2012 were extracted from spatial information taken from satellite images. The incidence rate ratio (IRR) was used to determine the relationship between spatio-temporal flooding patterns and the number of human leptospirosis cases. In addition, the area of flood coverage, duration of waterlogging, time lags between flood events, and a number of potential animal reservoirs were considered in a sub-analysis. There was no significant temporal trend of leptospirosis over the study period. Statistical analysis showed an inconsistent relationship between IRR and flooding across years and regions. Spatially, leptospirosis occurred repeatedly and predominantly in northeastern Thailand. Our findings suggest that flooding is less influential in leptospirosis transmission than previously assumed. High incidence of the disease in the northeastern region is explained by the fact that agriculture and animal farming are important economic activities in this area. The periodic rise and fall of reported leptospirosis cases over time might be explained by seasonal exposure from rice farming activities performed during the rainy season when flood events often occur. We conclude that leptospirosis remains an occupational disease in Thailand.