Dowel pinning for feline metacarpal and metatarsal fractures.

The goal of this retrospective study was to describe dowel pinning, and to compare the results of osteosynthesis and external coaptation of metacarpal and metatarsal fractures in cats. Evaluation of the medical records of 351 cats yielded 63 cats treated with dowel pinning, 35 cats treated with external coaptation and 14 cats treated with both methods within the same limb. All of the cats had been re-evaluated at an average of 2.8 years (six months - 15 years) postoperatively. Dowel pinning was superior to external coaptation when all fractured bones of a limb could be pinned. When internal fixation of multiple fractures was not feasible in all fractured bones due to comminution or fragments that were too short to pin, the outcome was not significantly different from cases treated with external coaptation alone. Malunion was seen in 16% of fractured bones in cats treated with external coaptation and occurred secondary to implant bending in 3% of fractured bones treated with dowel pinning. The latter refers to one operated cat, which had four metacarpal fractures in the same limb. Radiographs taken at re-evaluation showed implant migration within the medullary canal in two cats, although neither showed any signs of non-union or lameness. Non-union was seen in one operated cat, in which the fracture (MC IV) could not be completely reduced with a K-wire. Osteomyelitis did not occur. Dowel pinning is an easy, inexpensive and effective technique for repair of metacarpal and metatarsal fractures in cats.     

Sulphur supply impairs spread of Verticillium dahliae in tomato

Vascular wilt caused by the soil-borne fungus Verticillium dahliae is a major yield and quality-limiting disease across a broad spectrum of crop plants worldwide. Sulphur-enhanced plant defence mechanisms provide an opportunity to effectively and environmentally safely constrain the wilt disease levels in planta. To evaluate the influence of sulphur nutrition on the protective potential of these mechanisms, two near-isogenic tomato genotypes differing in fungal susceptibility, were treated with low or supra-optimal sulphur supply. Microscopic analysis revealed a significant sulphur-induced decrease in the amount of infected vascular cells in both genotypes. However, plant shoot and severely pathogen-affected root growth did not display this distinct alleviating influence of sulphur nutrition. Rates of leaf photosynthesis were impeded by Verticillium dahliae infection in both genotypes especially under low sulphur nutrition. However, assimilate transport rates in the phloem sap were enhanced by fungal infection more in the resistant genotype and under high sulphur nutrition suggesting a stronger sink for assimilates in infected plant tissues possibly involved in sugar-induced defence. A SYBR Green-based absolute quantitative Real-Time assay using a species-specific primer was developed which sensitively reflected sulphur nutrition-dependent changes in fungal colonization patterns. High sulphur nutrition significantly reduced fungal spread in the stem in both tomato genotypes. Concentrations of selected sulphur-containing metabolites revealed an increase of the major anti-oxidative redox buffer glutathione under high sulphur nutrition in response to fungal colonization. Our study demonstrates the existence of sulphur nutrition-enhanced resistance of tomato against Verticillium dahliae mediated by sulphur-containing defence compounds.     

Estimating evapotranspiration in semi-arid rangelands: connecting reference to actual evapotranspiration and the role of soil evaporation

In a context of water scarcity, efforts to increase landscape production should focus on improving water productivity. This requires an appreciation of the various components of evapotranspiration (ET), including soil evaporation (E_s) because the latter reflects ‘unproductive’ water loss. Both complex and simple algorithms have been developed to determine ET. In data scarce areas, developing and testing parsimonious algorithms is useful. This study sought to improve a simple single layer ET model by incorporating an E_s component. Empirical methods were also explored to predict ET from vegetation indices (VIs), leaf area index (LAI) and reference evapotranspiration (ET₀). A large aperture scintillometer and an eddy covariance (EC) system were used to validate the proposed algorithm at three sites over Grasslands and Albany Thicket biomes in the Eastern Cape, South Africa. There was good agreement between the observed and predicted ET with RMSE of 0.30–0.58 mm d^?1 when average daily observed ET was 0.43–3.24 mm. The VIs had moderate correlations with the observed data due to the significant role played by E_s (65%–84%) across the sites and stomatal conductance at the Albany Thicket site. The simple algorithms developed would make determining ET easier in data scarce regions.     

Mechanical properties of 18 different AO bone plates and the clamp-rod internal fixation system tested on a gap model construct.

OBJECTIVE: To compare the stiffness and strength of AO bone plates (DCP, LC-DCP, VCP, RCP, and LP) and the Clamp-Rod Internal Fixation System (CRIF). Study design: In vitro. Sample size: 12 individual implants of 18 plate dimensions and four sizes of CRIF, each corresponding to 2.0, 2.4/2.7, 3.5, or 4.5 mm screw sizes. METHODS: Implant-constructs of each plate and CRIF were created using Canevasit rods as a bone substitute in an unstable gap fracture model. Six implant-constructs of each type were tested under single cycle four-point bending loading, and six were tested under single cycle torsional loading until permanent plastic deformation occurred. RESULTS: Torsional stiffness and yield load of the DCP were always significantly greater than the CRIF within the same group. Bending properties of the 2.0 DCP were not significantly different to the 2.0 CRIF. The 2.7 DCP had significantly higher bending values than the 2.7 CRIF. The bending stiffness of the 3.5 DCP and 4.5 DCP was significantly less than their CRIF counterparts. While the bending yield load of the 3.5 DCP was significantly greater than the 3.5 CRIF, the bending yield load of the 4.5 DCP was significantly less than the 4.5 CRIF. CONCLUSION: A weakness was found in the torsional resistance of the CRIF constructs compared to the DCP constructs. CLINICAL SIGNIFICANCE: Bone holding power and applied screw torque should be considered when using the CRIF system in clinical application.     

340,000-year centennial-scale marine record of Southern Hemisphere climatic oscillation

In order to investigate rapid climatic changes at mid-southern latitudes, we have developed centennial-scale paleoceanographic records from the southwest Pacific that enable detailed comparison with Antarctic ice core records. These records suggest close coupling of mid-southern latitudes with Antarctic climate during deglacial and interglacial periods. Glacial sections display higher variability than is seen in Antarctic ice cores, which implies climatic decoupling between mid- and high southern latitudes due to enhanced circum-Antarctic circulation. Structural and temporal similarity with the Greenland ice core record is evident in glacial sections and suggests a degree of interhemispheric synchroneity not predicted from bipolar ice core correlations.     

Venus Thermosphere: In situ Composition Measurements, the Temperature Profile, and the Homopause Altitude

The neutral mass spectrometer on board the Pioneer Venus multiprobe bus measured composition and structral parameters of the dayside Venus upper atmosphere on 9 December 1978. Carbon dioxide and helium number densities were 6 x 10(6) and 5 x 10(6) per cubic centimeter, respectively, at an altitude of 150 kilometers. The mixing ratios of both argon-36 and argon-40 were approximately 80 parts per million at an altitude of 135 kilometers. The exospheric temperature from 160 to 170 kilometers was 285 +/- 10 K. The helium homopause was found at an altitude of about 137 kilometers.