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Disease surveillance in wildlife populations presents a logistical challenge, yet is critical in gaining a deeper understanding of the presence and impact of wildlife pathogens. Erinaceus coronavirus (EriCoV), a clade C Betacoronavirus, was first described in Western European hedgehogs (Erinaceus europaeus) in Germany. Here, our objective was to determine whether EriCoV is present, and if it is associated with disease, in Great Britain (GB). An EriCoV-specific BRYT-Green® real-time reverse transcription PCR assay was used to test 351 samples of faeces or distal large intestinal tract contents collected from casualty or dead hedgehogs from a wide area across GB. Viral RNA was detected in 10.8% (38) samples; however, the virus was not detected in any of the 61 samples tested from Scotland. The full genome sequence of the British EriCoV strain was determined using next generation sequencing; it shared 94% identity with a German EriCoV sequence. Multivariate statistical models using hedgehog case history data, faecal specimen descriptions and post-mortem examination findings found no significant associations indicative of disease associated with EriCoV in hedgehogs. These findings indicate that the Western European hedgehog is a reservoir host of EriCoV in the absence of apparent disease.
Andean Cenozoic shortening within the Malargüe fold–thrust belt of west-central Argentina has been dominated by basement faults largely influenced by pre-existing Mesozoic rift structures of the Neuquén basin system. The basement contractional structures, however, diverge from many classic inversion geometries in that they formed large hanging-wall anticlines with steeply dipping frontal forelimbs and structural relief in the order of several kilometres. During Cenozoic E–W shortening, the reactivated basement faults propagated into cover strata, feeding slip to shallow thrust systems that were later carried in piggyback fashion above newly formed basement structures, yielding complex thick- and thin-skinned structural relationships. In the adjacent foreland, Cenozoic clastic strata recorded the broad kinematic evolution of the fold–thrust belt. We present a set of structural cross-sections supported by regional surface maps and industry seismic and well data, along with new stratigraphic information for associated Neogene synorogenic foreland basin fill. Collectively, these results provide important constraints on the temporal and geometric linkages between the deeper basement faults (including both reactivated and newly formed structures) and shallow thin-skinned thrust systems, which, in turn, offer insights for the understanding of hydrocarbon systems in the actively explored Neuquén region of the Andean orogenic belt.
Intrauterine growth restriction (IUGR) and subsequent neonatal catch-up growth are implicated in the programming of increased appetite, adiposity and cardiometabolic diseases. Guinea pigs provide an alternate small animal model to rodents to investigate mechanisms underlying prenatal programming, being relatively precocial at birth, with smaller litter sizes and undergoing neonatal catch-up growth after IUGR. The current study, therefore, investigated postnatal consequences of spontaneous IUGR due to varying litter size in this species. Size at birth, neonatal, juvenile (post-weaning, 30–60 days) and adolescent (60–90 days) growth, juvenile and adolescent food intake, and body composition of young adults (120 days) were measured in 158 male and female guinea pigs from litter sizes of one to five pups. Compared with singleton pups, birth weight of pups from litters of five was reduced by 38%. Other birth size measures were reduced to lesser degrees with head dimensions being relatively conserved. Pups from larger litters had faster fractional neonatal growth and faster absolute and fractional juvenile growth rates (P<0.005 for all). Relationships of post-weaning growth, feed intakes and adult body composition with size at birth and neonatal growth rate were sex specific, with neonatal growth rates strongly and positively correlated with adiposity in males only. In conclusion, spontaneous IUGR due to large litter sizes in the guinea pig causes many of the programmed sequelae of IUGR reported in other species, including human. This may therefore be a useful model to investigate the mechanisms underpinning perinatal programming of hyperphagia, obesity and longer-term metabolic consequences.
A balanced cross-section spanning the Eastern Cordillera and Subandean Zone of southern Peru (13–15°S) constrains ~130 km (38%) of Cenozoic orogen-normal SW–NE Andean deformation accommodated by thick- and thin-skinned retro–arc fold–thrust belt shortening that overprinted pre-Andean Triassic normal faults. Zircon and apatite (U–Th)/He ages demonstrate continuous Oligocene to Miocene cooling of the Permo-Triassic Coasa pluton in the Eastern Cordillera. Zircon (U–Th)/He ages (~34–18 Ma) are reset and define a steep age versus elevation relationship. Apatite (U–Th)/He results reveal reset ages that define two spatially separated groups with ages of ~30–26 Ma and ~17–11 Ma. Detrital zircon U–Pb geochronologic results from Cretaceous–Cenozoic siliciclastic rocks from the Altiplano/Eastern Cordillera record Andean fold–thrust belt and magmatic-arc sediment sources. Correlative Subandean Zone rocks preserve a cratonic sediment contribution, with minor Andean sediment appearing in some Cenozoic rocks. We propose that earliest Andean deformation and structural compartmentalization of the Eastern Cordillera was linked to selective inversion of inherited Permo-Triassic basement-involved normal faults that guided subsequent thick- and thin-skinned deformation. Provenance variations between the hinterland and foreland depocentres reveal competing eastern and western sediment sources, reflecting an axial zone in the Eastern Cordillera that coincided with the inherited Triassic graben and impeded sediment source mixing. Our zircon and apatite (U–Th)/He ages are consistent with published constraints along strike and support pulses of Eocene to late Miocene exhumation that were likely driven by normal fault reactivation and protracted Eastern Cordillera deformation.
The first observations by a worldwide network of advanced interferometric gravitational wave detectors offer a unique opportunity for the astronomical community. At design sensitivity, these facilities will be able to detect coalescing binary neutron stars to distances approaching 400 Mpc, and neutron star–black hole systems to 1 Gpc. Both of these sources are associated with gamma-ray bursts which are known to emit across the entire electromagnetic spectrum. Gravitational wave detections provide the opportunity for ‘multi-messenger’ observations, combining gravitational wave with electromagnetic, cosmic ray, or neutrino observations. This review provides an overview of how Australian astronomical facilities and collaborations with the gravitational wave community can contribute to this new era of discovery, via contemporaneous follow-up observations from the radio to the optical and high energy. We discuss some of the frontier discoveries that will be made possible when this new window to the Universe is opened.
Identifying childhood predictors of binge eating and understanding risk mechanisms could help improve prevention and detection efforts. The aim of this study was to examine whether features of attention-deficit/hyperactivity disorder (ADHD), as well as childhood eating disturbances, predicted binge eating later in adolescence.
We studied specific risk factors for the development of binge eating during mid-adolescence among 7120 males and females from the Avon Longitudinal Study of Parents and Children (ALSPAC), a cohort study of children in the UK, using data from multiple informants to develop structural equation models. Repeated assessment of eating disturbances during childhood (mid-childhood overeating, late-childhood overeating and early-adolescent strong desire for food), as well as teacher- and parent-reported hyperactivity/inattention during mid- and late childhood, were considered as possible predictors of mid-adolescent binge eating.
Prevalence of binge eating during mid-adolescence in our sample was 11.6%. The final model of predictors of binge eating during mid-adolescence included direct effects of late-childhood overeating [standardized estimate 0.145, 95% confidence interval (CI) 0.038–0.259, p = 0.009] and early-adolescent strong desire for food (standardized estimate 0.088, 95% CI −0.002 to 0.169, p = 0.05). Hyperactivity/inattention during late childhood indirectly predicted binge eating during mid-adolescence (standardized estimate 0.085, 95% CI 0.007–0.128, p = 0.03) via late-childhood overeating and early-adolescent strong desire for food.
Our findings indicate that early ADHD symptoms, in addition to an overeating phenotype, contribute to risk for adolescent binge eating. These findings lend support to the potential role of hyperactivity/inattention in the development of overeating and binge eating.
Turbulent particle transport is investigated with a quasilinear theory that is motivated by the boron impurity transport experiments in the Alcator C-Mod. Eigenvalue problems for sets of reduced fluid equations for multi-component plasmas are solved for the self-consistent fluctuating field vectors composed of the electric potential φ, the main ion density δni, the impurity density δnz and the ion temperature fluctuation δTi. For Alcator C-Mod parameters, we investigate two drift wave models: (1) the density-gradient-driven impurity drift wave and (2) the ion-temperature-gradient-driven ion temperature gradient (ITG) mode. Analytic and numerical results for particle transport coefficients are derived and compared with the transport data and the neoclassical theory. We explore the ability of the model to explain impurity density profiles in three confinement regimes: H-mode, I-mode and internal transport barrier (ITB) regime in C-Mod. Related experiments reported on the Large Helical Device are briefly discussed.
Landscape epidemiology and landscape genetics combine advances in molecular techniques, spatial analyses and epidemiological models to generate a more real-world understanding of infectious disease dynamics and provide powerful new tools for the study of RNA viruses. Using dog rabies as a model we have identified how key questions regarding viral spread and persistence can be addressed using a combination of these techniques. In contrast to wildlife rabies, investigations into the landscape epidemiology of domestic dog rabies requires more detailed assessment of the role of humans in disease spread, including the incorporation of anthropogenic landscape features, human movements and socio-cultural factors into spatial models. In particular, identifying and quantifying the influence of anthropogenic features on pathogen spread and measuring the permeability of dispersal barriers are important considerations for planning control strategies, and may differ according to cultural, social and geographical variation across countries or continents. Challenges for dog rabies research include the development of metapopulation models and transmission networks using genetic information to uncover potential source/sink dynamics and identify the main routes of viral dissemination. Information generated from a landscape genetics approach will facilitate spatially strategic control programmes that accommodate for heterogeneities in the landscape and therefore utilise resources in the most cost-effective way. This can include the efficient placement of vaccine barriers, surveillance points and adaptive management for large-scale control programmes.
Phylogenetic analyses suggest lyssaviruses, including Rabies virus, originated from bats. However, the role of bats in the maintenance, transmission and evolution of lyssaviruses is poorly understood. A number of genetically diverse lyssaviruses are present in Africa, including Lagos bat virus (LBV). A high seroprevalence of antibodies against LBV was detected in Eidolon helvum bats. Longitudinal seroprevalence and age-specific seroprevalence data were analysed and capture–mark–recapture (CMR) analysis used to follow 98 bats over 18 months. These data demonstrate endemic infection, with evidence of horizontal transmission, and force of infection was estimated for differing age categories. The CMR analysis found survival probabilities of seronegative and seropositive bats were not significantly different. The lack of increased mortality in seropositive animals suggests infection is not causing disease after extended incubation. These key findings point towards acute transmission of bat lyssaviruses in adapted bat hosts that occurs at a far higher rate than the occurrence of disease.
Atom probe analyses of rapidly solidified, boron-doped Ni-24 at. % Al subjected to various heat treatments have shown boron segregation to a wide range of linear and planar defects. These include dislocations, superlattice intrinsic stacking faults, antiphase boundaries, twin boundaries, low-angle boundaries (dislocation cell walls), and high-angle grain boundaries. Boron coverage of these features was found to vary along a particular linear or planar defect and from boundary to boundary.
In alloys containing 0.24% boron, atom-probe field-ion microscopy (APFIM) revealed the presence of boron clusters in Ni-25 at. % Al and Ni-26 Al but not in Ni-24 Al. The observed boron clusters generally consisted of two to three boron atoms with a maximum size of 10 atoms. Quench rates that ranged from rapid solidification to furnace cooling had little effect on the clustering. The occurrence of the clustering coincides with a higher rate of boron strengthening as measured by an increase in the yield stress per atomic percent boron, and it also coincides with a reduced amount of boron segregation to grain boundaries. The levels of nickel and boron were highly variable on grain boundaries in rapidly solidified material and therefore no consistent indication of nickel enrichment at the grain boundaries associated with boron segregation was found. This result suggests that cosegregation of nickel with boron may not be necessary for the ductilization of Ni3Al by boron, since the rapidly solidified material is also ductilized by boron and exhibits segregation of only boron to the grain boundaries.
The objective of this study is to develop a metal-matrix composite based on the intermetallic alloy Ni3Al reinforced with Al2O3 fibers, with improved high-temperature strength and lower density compared to the matrix material. This paper summarizes results of initial fabrication and mechanical tests on specimens produced using IC-15 [Ni-24% Al-0.24% B (at.%)] and IC-218 [Ni-16.5% Al-8% Cr-0.4% Zr-0.1% B (at.%)], with 20 vol. % Al2O3 fibers. Fabrication methods include both hot-pressing and hot-extrusion. Mechanical tests include four-point bending and tensile tests. The integrity of the fiber-matrix interface was studied and correlated with mechanical properties. Tensile ductilities of approximately 10% at room temperature were achieved for Ni3Al/Al2O3 composites with controlled material processing and interfacial structure. Fabrication of composites by hot-extrusion produced better tensile properties at room temperature, but superplastic behavior (i.e., low strengths, high ductilities) at 1000°C.
This paper summarizes our recent study of NiAI+Fe+B alloy ribbons containing 4 to 20% Fe and doped with 300 wt ppm B. Alloy ribbons were successfully fabricated by rapid solidification via melt spinning. The alloys with 8% Fe and 34% Al-equivalent [=Al%+(Fe%)/2] showed the best bend ductility at room temperature. The ribbons exhibited a reversible martensite (body-centered orthorombic structure) to B2 transformation as evidenced by DSC, X-ray and TEM studies. The shape-memory effect, as characterized by measuring the recovery of bend angles with temperature, is sensitive to alloy composition, with the best recovery observed in SMA-15 (B-doped Ni-27% Al-14% Fe). Annealing at 600°C causes aging embrittlement; in particular, in alloys containing 12% Fe.
A survey by differential scanning calorimetry (DSC) and recovery during heating of indentations on a series of nickel-aluminum alloys showed that the Ni-36 at.% Al composition has the best potential for a recoverable shape memory effect at temperatures above 100°C. The phase transformations were studied by high temperature transmission electron microscopy (TEM) and by high temperature x-ray diffraction (HTXRD). Quenching from 1200°C resulted in a single phase, fully martensitic structure. The initial quenched-in martensites were found by both TEM and X-ray diffraction to consist of primarily a body centered tetragonal (bct) phase with some body centered orthorhombic (bco) phase present. On the first heating cycle, DSC showed an endothermic peak at 121°C and an exothermic peak at 289°C, and upon cooling a martensite exothermic peak at 115° C. Upon subsequent cycles the 289°C peak disappeared. High temperature X-ray diffraction, with a heating rate of 2°C/min, showed the expected transformation of bct phase to B2 between 100 and 200°C, however the bco phase remained intact. At 400 to 450°C the B2 phase transformed to Ni2Al and Ni5Al3. During TEM heating experiments a dislocation-free martensite transformed reversibly to B2 at temperatures less than 150°C. At higher temperatures (nearly 600°C) 1/3, 1/3, 1/3 reflections from an ω-like phase formed. Upon cooling, the 1/3, 1/3, 1/3 reflections disappeared and a more complicated martensite resulted. Boron additions suppressed intergranular fracture and, as expected, resulted in no ductility improvements. Boron additions and/or hot extrusion encouraged the formation of a superordered bct structure with 1/2, 1/2, 0 reflections.
Conventionally cast and hot-rolled Ni-Fe-AI-B alloys containing 4-20 at.% Fe, 23.9- 31.5 at.% Al, and 300 wppm B were investigated in this study. After oil quenching from 1300°C, all the alloys—except SMA-15 (27A1-14Fe)—have at least a two-phase microstructure, one phase of which is martensite with the characteristic plate morphology, and the other a globular second phase distributed throughout the microstructure. The amount of second phase generally increases with increasing Fe content. Alloys containing less than 14% Fe were found to be quite brittle at room temperature, indicating that a ductile second phase is at least partly responsible for the improved room-temperature ductility in the high-Fe alloys. The best tensile ductility (12%) was obtained in SMA-17 (23.9AI-20Fe) which was shown by X-ray diffraction to consist of 40% (mostly disordered) fcc [(Ni,Fe)3 (AI,Fe)] + 30% (partly ordered) bct martensite + 30% B2. Differential scanning calorimetry showed that the transformation temperatures for this alloy were MP = 65°C and AP = 95°C. Room-temperature tensile strains of 2-3% could be almost completely recovered in SMA-17 by heating for 3 min. at 600°C with the load removed. Upon subsequent cycling (i.e., strain-anneal cycling), the amount of strain recovery increased dramatically from 70% in the first cycle to nearly 100% after 4-5 cycles, indicating that cold work may help in improving the shape memory characteristics of this alloy. SMA-15 was found to have significantly higher transformation temperatures (Mp = 143°C and Ap = 170°C) than SMA-17; however, it is relatively brittle compared to SMA-17.
Binary NiAl suffers from a lack of strength and poor creep properties at and above 1000 K. Poor creep resistance in turn affects low cycle fatigue (LCF) lives at low strain ranges due to the additional interactions of creep damage. One approach for improving these properties involves microalloying with either Zr or N. As an integral part of a much larger alloying program the low cycle fatigue behavior of Zr and N doped nickel aluminides produced by extrusion of prealloyed powders has been investigated. Strain controlled LCF tests were performed in air at 1000 K. The influence of these microalloying additions on the fatigue life and cyclic stress response of polycrystalline NiAl are discussed.
A preliminary investigation was conducted for developing a thermomechanical procedure to refine the lamellar colony size of a fully lamellar structure and improve the balance of the mechanical properties of TiAl based alloys. The main experimental results are as follows: 1) The lamellar colony size in a fully lamellar structure can be reduced to 50 μm using a proper thermomechanical procedure. 2) The influence of colony size on the compressive yield stress of the fully lamellar structure is complex. In the large colony size region, the yield stress can be described by the Hall-Petch relation. In the small colony size region, the yield stress decreases as the colony size decreases. 3) The TiAl alloy, with a fine fully lamellar structure, has the best balance of tensile properties and fracture toughness.