71 research outputs found
Control via electron count of the competition between magnetism and superconductivity in cobalt and nickel doped NaFeAs
Using a combination of neutron, muon and synchrotron techniques we show how
the magnetic state in NaFeAs can be tuned into superconductivity by replacing
Fe by either Co or Ni. Electron count is the dominant factor, since Ni-doping
has double the effect of Co-doping for the same doping level. We follow the
structural, magnetic and superconducting properties as a function of doping to
show how the superconducting state evolves, concluding that the addition of 0.1
electrons per Fe atom is sufficient to traverse the superconducting domain, and
that magnetic order coexists with superconductivity at doping levels less than
0.025 electrons per Fe atom.Comment: 4 pages, 6 figure
The effect of deletion of the orphan G – protein coupled receptor (GPCR) gene MrgE on pain-like behaviours in mice
<p>Abstract</p> <p>Background</p> <p>The orphan GPCR <it>MrgE </it>is one of an extended family of GPCRs that are expressed in dorsal root ganglia (DRG). Based on these expression patterns it has been suggested that GPCRs like <it>MrgE </it>may play a role in nociception however, to date, no direct supporting evidence has emerged. We generated mutant mice lacking <it>MrgE </it>and examined the effects of deletion of this gene in three pain behavioural models. The effect of <it>MrgE </it>gene deletion on expression of <it>Mrgs </it>and genes involved in sensory neurone function was also investigated.</p> <p>Results</p> <p>The absence of <it>MrgE </it>had no effect on the development of pain responses to a noxious chemical stimulus or an acute thermal stimulus. However, in contrast, the development but not the maintenance of neuropathic pain was affected by deletion of <it>MrgE</it>. The expression of <it>Mrg </it>genes was not significantly affected in the <it>MrgE </it>knockout (KO) mice with the sole exception of <it>MrgF</it>. In addition, the expression of 77 of 84 genes involved in sensory neuron development and function was also unaffected by deletion of <it>MrgE</it>. Of the 7 genes affected by <it>MrgE </it>deletion, 4 have previously been implicated in nociception.</p> <p>Conclusion</p> <p>The data suggests that <it>MrgE </it>may play a role in selective pain behavioural responses in mice.</p
Differential Expression of Immune Response Genes in Steller Sea Lions (\u3ci\u3eEumetopias jubatus\u3c/i\u3e): An Indicator of Ecosystem Health?
Characterization of the polygenic and polymorphic features of the Steller sea lion major histocompatibility complex (MHC) provides an ideal window for evaluating immunologic vigor of the population and identifying emergence of new genotypes that reflect ecosystem pressures. MHC genotyping can be used to measure the potential immunologic vigor of a population. However, since ecosystem-induced changes to MHC genotype can be slow to emerge, measurement of differential expression of these genes can potentially provide real-time evidence of immunologic perturbations. MHC DRB genes were cloned and sequenced using peripheral blood mononuclear leukocytes derived from 10 Steller sea lions from southeast Alaska, Prince William Sound, and the Aleutian Islands. Nine unique DRB gene sequences were represented in each of ten animals. MHC DRB gene expression was measured in a subset of six sea lions. Although DRB in genomic DNA was identical in all individuals, relative levels of expressed DRB mRNA was highly variable. Selective suppression of MHC DRB genes could be indicative of geographically disparate environmental pressures, thereby serving as an immediate and sensitive indicator of population and ecosystem health
Aortic dissection: visualisation of aortic blood flow and quantification of wall shear stress using time-resolved, 3D phase-contrast MRI
Identification of genomic groups in the genus Stenotrophomonas using gyrB RFLP analysis
Stenotrophomonas maltophilia isolates have been recovered from various clinical samples, including the respiratory tract of cystic fibrosis (CF) patients, but this organism is also widespread in nature. Previously it has been shown that there is a considerable genomic diversity within S. maltophilia . The aims of our study were to determine the taxonomic resolution of restriction fragment length polymorphism (RFLP) analysis of the polymerase chain reaction-amplified gyrB gene for the genus Stenotrophomonas . Subsequently, we wanted to use this technique to screen a set of S. maltophilia isolates (with emphasis on a specific subset, isolates recovered from CF patients), to assess the genomic diversity within this group. In this study we investigated 191 Stenotrophomonas sp. isolates (including 40 isolates recovered from CF patients) by means of gyrB RFLP. The taxonomic resolution of gyrB RFLP, and hence its potential as an identification tool, was confirmed by comparison with results from published and novel DNA–DNA hybridisation experiments. Our data also indicate that the majority of CF isolates grouped in two clusters. This may indicate that isolates from specific genomic groups have an increased potential for colonisation of the respiratory tract of CF patients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72378/1/S0928-8244_03_00307-9.pd
Mother-offspring recognition via contact calls in cattle, Bos taurus.
Individual recognition in gregarious species is fundamental in order to avoid misdirected parental investment. In ungulates, two very different parental care strategies have been identified: ‘hider’ offspring usually lie concealed in vegetation whereas offspring of ‘follower’ species remain with their mothers while they forage. These two strategies have been suggested to impact on mother-offspring vocal recognition, with unidirectional recognition of the mother by offspring occurring in hiders and bidirectional recognition in followers. In domestic cattle, Bos taurus, a facultative hider species, vocal communication and recognition have not been studied in detail under free-ranging conditions, where cows and calves can graze freely and where hiding behaviour can occur. We hypothesized that, as a hider species, cattle under these circumstances would display unidirectional vocal recognition. To test this hypothesis, we conducted playback experiments using mother-offspring contact calls. We found that cows were more likely to respond, by moving their ears and/or looking, turning or walking towards the loudspeaker, to calls of their own calves than to calls from other calves. Similarly, calves responded more rapidly, and were more likely to move their ears and/or look, turn or walk towards the loudspeaker, and to call back and/or meet their mothers, in response to calls from their own mothers than to calls from other females. Contrary to our predictions, our results suggest that mother-offspring vocal individual recognition is bidirectional in cattle. Additionally, mothers of younger calves tended to respond more strongly to playbacks than mothers of older calves. Therefore, mother responses to calf vocalizations are at least partially influenced by calf age
Burkholderia anthina sp. nov. and Burkholderia pyrrocinia , two additional Burkholderia cepacia complex bacteria, may confound results of new molecular diagnostic tools
Nineteen Burkholderia cepacia -like isolates of human and environmental origin could not be assigned to one of the seven currently established genomovars using recently developed molecular diagnostic tools for B. cepacia complex bacteria. Various genotypic and phenotypic characteristics were examined. The results of this polyphasic study allowed classification of the 19 isolates as an eighth B. cepacia complex genomovar ( Burkholderia anthina sp. nov.) and to design tools for its identification in the diagnostic laboratory. In addition, new and published data for Burkholderia pyrrocinia indicated that this soil bacterium is also a member of the B. cepacia complex. This highlights another potential source for diagnostic problems with B. cepacia -like bacteria.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71564/1/j.1574-695X.2002.tb00584.x.pd
Derivation of High Spatial Resolution Albedo from UAV Digital Imagery:Application over the Greenland Ice Sheet
Measurements of albedo are a prerequisite for modeling surface melt across the Earth's cryosphere, yet available satellite products are limited in spatial and/or temporal resolution. Here, we present a practical methodology to obtain centimeter resolution albedo products with accuracies of ?5% using consumer-grade digital camera and unmanned aerial vehicle (UAV) technologies. Our method comprises a workflow for processing, correcting and calibrating raw digital images using a white reference target, and upward and downward shortwave radiation measurements from broadband silicon pyranometers. We demonstrate the method with a set of UAV sorties over the western, K-sector of the Greenland Ice Sheet. The resulting albedo product, UAV10A1, covers 280 km2, at a resolution of 20 cm per pixel and has a root-mean-square difference of 3.7% compared to MOD10A1 and 4.9% compared to ground-based broadband pyranometer measurements. By continuously measuring downward solar irradiance, the technique overcomes previous limitations due to variable illumination conditions during and between surveys over glaciated terrain. The current miniaturization of multispectral sensors and incorporation of upward facing radiation sensors on UAV packages means that this technique could become increasingly common in field studies and used for a wide range of applications. These include the mapping of debris, dust, cryoconite and bioalbedo, and directly constraining surface energy balance models.publishersversionPeer reviewe
Estimating the Worldwide Extent of Illegal Fishing
Illegal and unreported fishing contributes to overexploitation of fish stocks and is a hindrance to the recovery of fish populations and ecosystems. This study is the first to undertake a world-wide analysis of illegal and unreported fishing. Reviewing the situation in 54 countries and on the high seas, we estimate that lower and upper estimates of the total value of current illegal and unreported fishing losses worldwide are between 23.5 bn annually, representing between 11 and 26 million tonnes. Our data are of sufficient resolution to detect regional differences in the level and trend of illegal fishing over the last 20 years, and we can report a significant correlation between governance and the level of illegal fishing. Developing countries are most at risk from illegal fishing, with total estimated catches in West Africa being 40% higher than reported catches. Such levels of exploitation severely hamper the sustainable management of marine ecosystems. Although there have been some successes in reducing the level of illegal fishing in some areas, these developments are relatively recent and follow growing international focus on the problem. This paper provides the baseline against which successful action to curb illegal fishing can be judged
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