2,070 research outputs found

    Technical innovation changes standard radiographic protocols in veterinary medicine: is it necessary to obtain two dorsoproximal-palmarodistal oblique views of the equine foot when using computerised radiography systems?

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    Since the 1950s, veterinary practitioners have included two separate dorsoproximal–palmarodistal oblique (DPr–PaDiO) radiographs as part of a standard series of the equine foot. One image is obtained to visualise the distal phalanx and the other to visualise the navicular bone. However, rapid development of computed radiography and digital radiography and their post-processing capabilities could mean that this practice is no longer required. The aim of this study was to determine differences in perceived image quality between DPr–PaDiO radiographs that were acquired with a computerised radiography system with exposures, centring and collimation recommended for the navicular bone versus images acquired for the distal phalanx but were subsequently manipulated post-acquisition to highlight the navicular bone. Thirty images were presented to four clinicians for quality assessment and graded using a 1–3 scale (1=textbook quality, 2=diagnostic quality, 3=non-diagnostic image). No significant difference in diagnostic quality was found between the original navicular bone images and the manipulated distal phalanx images. This finding suggests that a single DPr–PaDiO image of the distal phalanx is sufficient for an equine foot radiographic series, with appropriate post-processing and manipulation. This change in protocol will result in reduced radiographic study time and decreased patient/personnel radiation exposure

    Comparison of measured and EF5-r derived N₂O fluxes from a spring-fed river

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    There is considerable uncertainty in the estimates of indirect N₂O emissions as defined by the Intergovernmental Panel on Climate Change's (IPCC) methodology. Direct measurements of N₂O yields and fluxes in aquatic river environments are sparse and more data are required to determine the role that rivers play in the global N₂O budget. The objectives of this research were to measure the N₂O fluxes from a spring-fed river, relate these fluxes to the dissolved N₂O concentrations and NO₃–N loading of the river, and to try and define the indirect emission factor (EF5-r) for the river. Gas bubble ebullition was observed at the river source with bubbles containing 7.9 µL N₂O L⁻¹. River NO₃–N and dissolved N₂O concentrations ranged from 2.5 to 5.3 mg L⁻¹ and 0.4 to 1.9 µg N₂O-N L⁻¹ respectively with N₂O saturation reaching 404%. Floating headspace chambers were used to sample N₂O fluxes. N₂O–N fluxes were significantly related to dissolved N₂O–N concentrations (r² = 30.6) but not to NO₃–N concentrations. The N₂O–N fluxes ranged from 38-501 µg m⁻² h⁻¹, averaging 171 µg m⁻² h⁻¹ (± Std. Dev. 85) overall. The measured N₂O–N fluxes equated to an EF5-r of only 6.6% of that calculated using the IPCC methodology, and this itself was considered to be an over-estimate due to the degassing of antecedent dissolved N₂O present in the groundwater that fed the river

    Microarray karyotyping of commercial wine yeast strains reveals shared, as well as unique, genomic signatures

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    BACKGROUND: Genetic differences between yeast strains used in wine-making may account for some of the variation seen in their fermentation properties and may also produce differing sensory characteristics in the final wine product itself. To investigate this, we have determined genomic differences among several Saccharomyces cerevisiae wine strains by using a "microarray karyotyping" (also known as "array-CGH" or "aCGH") technique. RESULTS: We have studied four commonly used commercial wine yeast strains, assaying three independent isolates from each strain. All four wine strains showed common differences with respect to the laboratory S. cerevisiae strain S288C, some of which may be specific to commercial wine yeasts. We observed very little intra-strain variation; i.e., the genomic karyotypes of different commercial isolates of the same strain looked very similar, although an exception to this was seen among the Montrachet isolates. A moderate amount of inter-strain genomic variation between the four wine strains was observed, mostly in the form of depletions or amplifications of single genes; these differences allowed unique identification of each strain. Many of the inter-strain differences appear to be in transporter genes, especially hexose transporters (HXT genes), metal ion sensors/transporters (CUP1, ZRT1, ENA genes), members of the major facilitator superfamily, and in genes involved in drug response (PDR3, SNQ1, QDR1, RDS1, AYT1, YAR068W). We therefore used halo assays to investigate the response of these strains to three different fungicidal drugs (cycloheximide, clotrimazole, sulfomethuron methyl). Strains with fewer copies of the CUP1 loci showed hypersensitivity to sulfomethuron methyl. CONCLUSION: Microarray karyotyping is a useful tool for analyzing the genome structures of wine yeasts. Despite only small to moderate variations in gene copy numbers between different wine yeast strains and within different isolates of a given strain, there was enough variation to allow unique identification of strains; additionally, some of the variation correlated with drug sensitivity. The relatively small number of differences seen by microarray karyotyping between the strains suggests that the differences in fermentative and organoleptic properties ascribed to these different strains may arise from a small number of genetic changes, making it possible to test whether the observed differences do indeed confer different sensory properties in the finished wine

    Wind Structure in Winter Storms

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77570/1/AIAA-511-343.pd

    The Longhorn Array Database (LAD): An Open-Source, MIAME compliant implementation of the Stanford Microarray Database (SMD)

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    BACKGROUND: The power of microarray analysis can be realized only if data is systematically archived and linked to biological annotations as well as analysis algorithms. DESCRIPTION: The Longhorn Array Database (LAD) is a MIAME compliant microarray database that operates on PostgreSQL and Linux. It is a fully open source version of the Stanford Microarray Database (SMD), one of the largest microarray databases. LAD is available at CONCLUSIONS: Our development of LAD provides a simple, free, open, reliable and proven solution for storage and analysis of two-color microarray data

    Extension rates across the northern Shanxi Grabens, China, from Quaternary geology, seismicity and geodesy

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    Discrepancies between geological, seismic and geodetic rates of strain can indicate that rates of crustal deformation, and hence seismic hazard, are varying through time. Previous studies in the northern Shanxi Grabens, at the northeastern corner of the Ordos Plateau in northern China, have found extension rates of anywhere between 0 and 6 mm a−1 at an azimuth of between 95° and 180°. In this paper we determine extension rates across the northern Shanxi Grabens from offset geomorphological features and a variety of Quaternary dating techniques (including new IRSL and Ar-Ar ages), a Kostrov summation using a 700 yr catalogue of historical earthquakes, and recent campaign GPS measurements. We observe good agreement between Quaternary, seismic and geodetic rates of strain, and we find that the northern Shanxi Grabens are extending at around 1–2 mm a−1 at an azimuth of ≈151°. The azimuth of extension is particularly well constrained and can be reliably inferred from catalogues of small earthquakes. We do not find evidence for any substantial variations in extension rate through time, though there is a notable seismic moment rate deficit since 1750. This deficit could indicate complex fault interactions across large regions, aseismic accommodation of deformation, or that we are quite late in the earthquake cycle with the potential for larger earthquakes in the relatively near future

    Modification of classical electron transport due to collisions between electrons and fast ions

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    A Fokker-Planck model for the interaction of fast ions with the thermal electrons in a quasi-neutral plasma is developed. When the fast ion population has a net flux (i.e. the distribution of the fast ions is anisotropic in velocity space) the electron distribution function is significantly perturbed from Maxwellian by collisions with the fast ions, even if the fast ion density is orders of magnitude smaller than the electron density. The Fokker-Planck model is used to derive classical electron transport equations (a generalized Ohm's law and a heat flow equation) that include the effects of the electron-fast ion collisions. It is found that these collisions result in a current term in the transport equations which can be significant even when total current is zero. The new transport equations are analyzed in the context of a number of scenarios including α\alpha particle heating in ICF and MIF plasmas and ion beam heating of dense plasmas
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