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Studies of blood parasite infection in nestling birds rarely find a high prevalence of infection. This is likely due to a combination of short nestling periods (limiting the age at which nestlings can be sampled) and long parasite prepatent periods before gametocytes can be detected in peripheral blood. Here we examine rates of blood parasite infection in nestlings from three Columbid species in the UK. We use this system to address two key hypotheses in the epidemiology of avian haemoparasites: first, that nestlings in open nests have a higher prevalence of infection; and second, that nestlings sampled at 14 days old have a higher apparent infection rate than those sampled at 7 days old. Open-nesting individuals had a 54% infection rate compared with 25% for box-nesters, probably due to an increased exposure of open-nesting species to dipteran vectors. Nestlings sampled at 14 days had a 68% infection rate compared with 32% in nestlings sampled at 7 days, suggesting that rates of infection in the nest are high. Further work should examine nestlings post-fledging to identify rates of successful parasite infection (as opposed to abortive development within a dead-end host) as well as impacts on host post-fledging survival and behaviour.
Post-fledging survival plays a vital role in the dynamics of bird populations and yet is the least-studied avian life-stage. Habitat requirements post-fledging may have important implications for behaviour and survival, especially for declining populations in landscapes that have undergone wide-scale anthropogenic modification, resulting in an altered distribution and composition of habitats. The European Turtle Dove is a widespread but rapidly declining species both within the UK and across Europe. Reduced seed food availability is thought to influence breeding success of this species, but it is not known whether post-fledging survival may also be influenced by seed availability. Here, we use leg-ring radio-tag attachments to monitor post-fledging survival and movements in 15 Turtle Dove nestlings from eight nests monitored during 2014 as part of a wider autecological study. Fledglings remained in close proximity to their nest for three weeks post-tagging, spending more than half their time in the immediate vicinity (within ∼20 m) of the nest. 95% of foraging trips during this period were within 329 m of the nest and fledglings selected seed-rich habitat (semi-natural grassland, low-intensity grazing, fallow and quarries). Fledglings that were heavier and in better body condition at seven days old were more likely to survive for 30 days post-fledging, and the proportion of available seed-rich habitat was a strong predictor of nestling weight and condition at seven days old. Whilst our sample size is modest, this study highlights the crucial role of food availability in juvenile survival, both while adults are feeding nestlings, and to recently fledged young, and the potential for agri-environment schemes providing foraging and nesting habitats in close proximity to provide important benefits.
Epidemiological studies have established an association between obesity, insulin resistance, type 2 diabetes and a number of cancer types. Research has focused predominantly on altered endocrine factors, growth factors and signalling pathways, with little known in man about the immune involvement in the relevant pathophysiological processes. Moreover, in an era of exciting new breakthroughs in cancer immunotherapy, there is also a need to study the safety and efficacy of immunotherapeutics in the complex setting of inflammatory-driven obesity-associated cancer. This review addresses key immune cell subsets underpinning obesity-associated inflammation and describes how such immune compartments might be targeted to prevent and treat obesity-associated cancer. We propose that the modulation, metabolism, migration and abundance of pro- and anti-inflammatory cells and tumour-specific T cells might be therapeutically altered to both restore immune balance, alleviating pathological inflammation, and to improve anti-tumour immune responses in obesity-associated cancer.
Studies incorporating the ecology of clinical and sub-clinical disease in wild populations of conservation concern are rare. Here we examine sub-clinical infection by Trichomonas gallinae in a declining population of free-living European Turtle Doves and suggest caseous lesions cause mortality in adults and nestlings through subsequent starvation and/or suffocation. We found a 100% infection rate by T. gallinae in adult and nestling Turtle Doves (n = 25) and observed clinical signs in three adults and four nestlings (28%). Adults with clinical signs displayed no differences in any skeletal measures of size but had a mean 3·7% reduction in wing length, with no overlap compared to those without clinical signs. We also identified T. gallinae as the suggested cause of mortality in one Red-legged Partridge although disease presentation was different. A minimum of four strains of T. gallinae, characterized at the ITS/5·8S/ITS2 ribosomal region, were isolated from Turtle Doves. However, all birds with clinical signs (Turtle Doves and the Red-legged Partridge) carried a single strain of T. gallinae, suggesting that parasite spill over between Columbidae and Galliformes is a possibility that should be further investigated. Overall, we highlight the importance of monitoring populations for sub-clinical infection rather than just clinical disease.
Observation of GaN-based islands surrounded by V-defects in the barrier layer of green LED is reported for InGaN MQWs deposited under no hydrogen or at growth temperatures of less than 800°C. Nanoscale mechanical properties of the areas enclosed and outside of the ring defects does not show any appreciable variation as measured by UFM. Chemical etching of the MQW structure in addition to cross-sectional TEM analysis ruled out the possibility of growth of inversion domains of N-polar GaN in a Ga-polar GaN matrix.
Development of devices storing and delivering high-energy power such as supercapacitors is necessary to assist intermittent sources of energy. Most of the commercial systems are carbon-based, but due to their high surface charge, oxides offer a valuable alternative for high-rate energy storage. Among them, layered transition metal oxides with mixed valence properties present both good electronic and ionic conductivities suitable for application to electrochemical applications intermediate between capacitors and batteries. This work focuses on lamellar oxide bronzes based on cobalt MxCoO2 and vanadium MxV2O5 (M = H, Li, Na or K). A low temperature synthesis leads to high specific area particles (above 100 m2/g). Hydrated and anhydrous NaxCoO2 are promising cathode materials for aqueous supercapacitors, with a high capacity of more than 100 mAh/g obtained under 20 mV/s for the hydrated NaxCoO2. The MxV2O5 bronzes appear to be good candidates for organic supercapacitors, especially the LixV2O5 bronze, which shows a high stable capacity above 100 mAh/g (at 20 mV/s ie a charging time of 125 s).
EMU is a wide-field radio continuum survey planned for the new Australian Square Kilometre Array Pathfinder (ASKAP) telescope. The primary goal of EMU is to make a deep (rms ∼ 10 μJy/beam) radio continuum survey of the entire Southern sky at 1.3 GHz, extending as far North as +30° declination, with a resolution of 10 arcsec. EMU is expected to detect and catalogue about 70 million galaxies, including typical star-forming galaxies up to z ∼ 1, powerful starbursts to even greater redshifts, and active galactic nuclei to the edge of the visible Universe. It will undoubtedly discover new classes of object. This paper defines the science goals and parameters of the survey, and describes the development of techniques necessary to maximise the science return from EMU.
The chemistry of the aqueous environment inside any breached waste packages is critical to the release of radionuclides from the waste packages for high-level waste disposal. A corrosion test cell that simulates some aspects of the internal geometry of the waste packages has been designed to investigate changes in the in-package solution chemistry. A series of tests was conducted to evaluate solution chemistry variations as a function of applied potential and temperature using a specimen of Type 316L stainless steel with a predrilled hole as a simulated pit. A micro-syringe was used to extract solutions from inside and outside the pit. The solutions were analyzed for cation concentrations using capillary electrophoresis, and the pH was measured using a micro-electrode. Preliminary measurements showed substantially high cation concentrations inside the pit due to anodic dissolution of Type 316L stainless steel. The solution pH became considerably acidic, reaching a value of 2.6. These results suggest that interactions of waste package internal structural components with incoming water may have significant influence on the evolution of water chemistry and the subsequent corrosion of waste forms such as spent nuclear fuel.
We investigate the ion beam damage of clean Au (001) single crystals prepared under standard surface science techniques using sputter - anneal cycles. Under initial ion milling conditions using 4 keV Xe ions a significant amount of Xe was implanted into the bulk of the crystal. After a short period of time a Xe super structure developed which yielded 12 Å moire fringes under bright field imaging conditions. With a short anneal the implanted Xe concentration was reduced to the detection limit of Parallel Electron Energy Loss Spectroscopy (PEELS). With extended annealing, the bulk point defect concentration slowly decayed, independent of the surface reconstruction.
Transmission electron microscopy (TEM) was used to characterize the microstructure in GaN films deposited by two different methods. An 11 μm thick film was deposited directly on a sapphire substrate by HVPE; an 8 μm thick film was deposited on a 15 nm buffer layer of AIN on sapphire by MOVPE. The dislocation densities in the top layer of the HVPE and MOVPE ilms were ∼109 cm-2 and ∼5 x 109 cm-2 respectively. In the HVPE film this was almost exclusively threading dislocations (TDs), ∼70% of which had edge character. In addition to the TDs, the MOVPE sample also contained an appreciable number of dislocations lying in the basal plane. The microstructure of each film was dominated by a subgrain structure of slightly misoriented cells. In the MOVPE specimen, approximately 90% of the TDs were associated with subgrain walls, whereas only approximately 75% of the dislocations in the HVPE specimen were associated with walls. Both the HVPE and MOVPE samples experienced 40% coarsening of the cells through the thickness of the film. The subgrains of the MOVPE sample were 75% smaller than those in the HVPE sample (350 and 1300 nm, respectively). The average dislocation spacing in the walls was 50% smaller in the MOVPE sample than in the HVPE sample (82 and 180 nm, respectively).
First-principle, tight binding, and semi-empirical embedded atom calculations are used to investigate a tetragonal phase transformation in gold nanowires. As wire diameter is decreased, tight binding and modified embedded atom simulations predict a surface-stress-induced phase transformation from a face-centered-cubic (fcc) <100> nanowire into a body-centered-tetragonal (bct) nanowire. In bulk gold, all theoretical approaches predict a local energy minimum at the bct phase, but tight binding and first principle calculations predict elastic instability of the bulk bct phase. The predicted existence of the stable bct phase in the nanowires is thus attributed to constraint from surface stresses. The results demonstrate that surface stresses are theoretically capable of inducing phase transformation and subsequent phase stability in nanometer scale metallic wires under appropriate conditions.
In this paper, we wish to report our preliminary experimental results from the photoluminescence (PL) studies in a Mn-ion implanted silicon-rich oxide (SRO) thin film. At 4 K, a broad PL peak, centered at ~ 1.2 eV, was observed. It is blue-shifted from the Si substrate peak at ~ 1.1 eV. The temperature (T) dependence of PL was carried out at zero magnetic (B) field and B = 0.5 Tesla, respectively, and showed quantitatively different behaviors. At B = 0, the PL intensity increases very slowly at low temperatures and reaches a maximal value at ~ 40 K. It then decreases as T is further increased. At B = 0.5 Tesla, the peak temperature (Tpeak), whether the intensity is maximal, moves to ~ 80-100 K, and the decreasing rate beyond Tpeak is much smaller than that at B = 0. We speculate that these two different behaviors might reveal, possibly, a ferromagnetic ordering in Mn-ion doped silicon nanocrystals.
Ion implantation doping of Si through an SiO2 overlayer is of interest for fabrication of a range of devices on the pathway to development of a solid–state quantum computer (SSQC). The fabrication requirements of devices based on the Kane architecture typically involve implantation through a pre-existing thin device–quality thermal oxide at low fluences ∼1011 cm−2 and ion energies in the range 10 – 20 keV. Here we present results from a deep level transient spectroscopy studies of ion–implanted MOS capacitors in which interface–trap densities have been measured in as–grown and H–passivated thermal oxides and in ion implanted and rapid–thermally processed devices. For thin oxides of 5nm or less and low ion fluences we find that implantation does not significantly increase interface trap densities and somewhat surprisingly that it can even be beneficial when the interface trap density is abnormally high, (∼ 1 × 1011cm−2.eV−1) in the as-grown oxide.
The process of encapsulating antibodies in sol-gel was used for sensing various hormones, specifically cortisol, insulin, and C-peptide. A sol-gel optical biosensor for cortisol has been developed for monitoring of crew health on-orbit during space missions. Our studies involving silica sol-gel materials with competitive immunoassays demonstrated linear calibration for cortisol in the range of 2-60 μg/dL, which covers the physiological range of cortisol blood concentration for an adult (2-28 μg/dL). The method of standard additions was used to analyze human serum samples sent to us from a NASA laboratory. Our sol-gel immunosensor values were typically within 20% of the values obtained by NASA-JSC using traditional immuno-binding techniques, with some values having less than a 5% error. Initial results are presented for sensing the hormones insulin and C-peptide.
Studies show an inverse relationship between breakfast frequency and weight gain. This may reflect poor eating habits generally and associated low physical activity (PA) or direct impacts of breakfast on mechanisms leading to lethargy and reduced PA. The relationship between breakfast frequency and PA is inconclusive. We aimed to determine whether breakfast frequency is associated with PA levels in British adolescents independent of body composition and socio-economic status (SES). Habitual breakfast frequency (self-report questionnaire) was assessed in 877 adolescents (43 % male, age 14·5 (sd 0·5) years old). PA was measured over 5 d (accelerometry, average counts/min; cpm). Associations between daily PA and breakfast frequency were assessed using linear regression adjusted for body fat percentage and SES. Effect modification by sex and associations with PA during the morning (06.00–12.00 hours) were explored. For boys, there were no significant associations between breakfast frequency and PA. For girls, less frequent breakfast consumption was significantly associated with lower PA (cpm) during the morning (occasional v. frequent β − 6·1 (95 % CI − 11·1, − 1·1), P = 0·017) when adjusted for body fat percentage and SES. There were no associations between PA and breakfast consumption over the whole day; however, for girls, less frequent breakfast consumption may be associated with lower PA levels during the morning, suggesting that breakfast consumption should perhaps be taken into consideration when aiming to promote PA in adolescent girls.