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131.
Xia LIANG Jizheng HE Fusuo ZHANG Qirong SHEN Jinshui WU Iain M. YOUNG Anthony G. O'DONNELL Ligang WANG Enli WANG Julian HILL Deli CHEN 《农业科学与工程前沿(英文版)》2020,7(3):347-355
Soil is the foundation for sustainable food production and environmental protection. Created by unsustainable land management practices and a range of social, economic and environmental drivers, soil degradation and pollution have been an ongoing threat to international food security and environmental quality. Soil degradation and pollution assessments are, however, often focused on the soil itself with little scope to devise new soil management approaches that match food production systems and/or environmental protection. This study draws lessons from an Australia-China Joint Research Center Program, Healthy Soils for Sustainable Food Production and Environmental Quality: a research platform that has brought together multi-disciplinary approaches from world-renowned universities and research organizations in Australia and China. To this end, a framework is presented for future soil management in a new way that combines excellence in research, industry and policymakers in a partnership that will ensure not only the right focus of the research but also that high-quality outputs will be transferable to industry and end-users. 相似文献
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Nematode (Caenorhabditis elegans) movement in sand as affected by particle size, moisture and the presence of bacteria (Escherichia coli) 总被引:1,自引:0,他引:1
The movement of bacterial-feeding nematodes (Caenorhabditis elegans) through sand was investigated using a range of sand sizes, equilibrated at a range of matric potentials, in the presence or absence of an attractant source ( Escherichia coli) at the distal end of a column . In the presence of E. coli there was significantly greater movement of the nematode population towards the E. coli population, and the extent of the movement depended on the matric potential of the sand. Over time, an increasing proportion of the C. elegans population responded to the presence of the E. coli . The processes controlling these effects are discussed with respect to taxis and kinesis mechanisms of the nematode population, and with regard to the diffusive characteristics of the physical structure of the sand. 相似文献
135.
L Hesselink SS Orlov A Liu A Akella D Lande RR Neurgaonkar 《Science (New York, N.Y.)》1998,282(5391):1089-1094
Optically gated recording and nonvolatile readout in a digital volume holographic data storage system that uses a pair of mutually incoherent light sources during recording and only one for readout were demonstrated recently. This approach used stoichiometric lithium niobate, which after post-growth processing gave rise to an at least two orders of magnitude improvement in sensitivity over the best materials reported previously. It is also shown that by adding certain dopants (iron and manganese) to near-stoichiometric lithium niobate, the dark storage time and gating efficiency can be increased compared with previous work. The underlying physical mechanisms of gated recording and the effectiveness of the gating process responsible for this manifold improved performance are discussed, and bipolarons and small polarons are identified as the responsible photorefractive species. 相似文献
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JACK R. SNYDER DVM PhD Diplomate ACVS JOHN R. PASCOE BVSc PhD Diplomate ACVS HARVEY J. OLANDER DVM PhD Diplomate ACVP DAVE M. HINDS ROBERT YOUNG DVM WALTER S. TYLER DVM PhD 《Veterinary surgery : VS》1990,19(6):446-455
Ten horses were euthanatized before, during, or after surgery to correct severe volvulus of the large colon. At surgery, the colonic serosa changed from blue-gray, blue or purple toward a more normal pink in seven horses after the volvulus was corrected. The mucosa consistently remained black or dark red. Results of postmortem colonic microangiography revealed perfusion of the serosa and the circular and longitudinal muscle layers, but mucosal perfusion was limited by thrombosis in the muscularis mucosae and submucosa. There was evidence of thrombosis of the mesenteric colic vessels in six horses. Damage to the colonic vascular system, especially thromboembolism in the submucosa, may be an important limitation to colonic viability after surgical correction of volvulus of the large colon. 相似文献
138.
C.S. CELLY W.N. McDONELL S.S. YOUNG & W.D. BLACK 《Journal of veterinary pharmacology and therapeutics》1997,20(6):464-471
In the present study, the hypoxaemic potential of four α2 agonists possessing different selectivity for α2 adrenoceptors and of a saline placebo was studied in five clinically healthy sheep using a randomized Latin square design and equipotent sedative doses. Baseline values for heart rate (HR), mean arterial pressure (MAP), arterial oxygen (PaO2) and carbon dioxide (PaCO2) tensions, respiration rate and maximum change in pleural pressure (ΔPpl) were obtained, followed by the intravenous administration of either: xylazine (150 μg/kg); romifidine (50 μg/kg); detomidine (30 μg/kg); medetomidine (10 μg/kg) or placebo. Subsequent recordings were made up to 60 min after drug administration. No significant (P 0.05) alterations in any variable occurred with placebo. All the α2 agonists significantly (P 0.05) decreased PaO2 levels without a significant (P 0.05) change in PaCO2. The lowest PaO2 values were 29–42 mm Hg (3.9–5.5 kPa) with no significant difference between drugs. Respiratory rate and ΔPpl increased significantly within 2 min of drug administration; the duration of this effect varied with the α2 agonist, lasting longest with romifidine. As compared to the saline treated group, a significant increase in MAP was observed up to 10 min after administration of romifidine and detomidine, however, a significant decrease was seen at 10 and 45 min after xylazine and medetomidine, respectively. The α2 agonists studied induced a similar change in PaO2 at peak effect, despite their reported variable selectivity for α2 vs. α1 adrenoceptors. 相似文献
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To study the transport of plaice (Pleuronectes platessa L.) eggs and larvae in the eastern Irish Sea, we constructed a 3D‐baroclinic physical model and coupled it to a particle‐tracking scheme that allowed aspects of larval behaviour to be simulated. Starting positions for eggs were based upon data from a series of ichthyoplankton surveys and final positions were compared with results of settled plaice distributions from two beam trawl surveys conducted on beaches around the eastern Irish Sea. If simulated larval behaviour was limited to passive drift or horizontal swimming, the particles diffused away from the spawning areas but failed to reach nursery grounds in significant numbers (85–90% remaining offshore). In contrast, switching on circatidal vertical swimming significantly increased the numbers of larvae reaching the coast (only 23–30% remained offshore). Particles tended to accumulate in bays and estuaries and this pattern compared well with the distribution of settled plaice from the field surveys. Studies in the southern North Sea (where spawning and nursery grounds are widely separated) have also demonstrated the importance of selective tidal stream transport for successful recruitment of settling plaice to nursery grounds. Although our understanding of the ontogeny of this behaviour is still poor, the model results presented suggest that this aspect of behaviour is a key factor influencing plaice settlement success. 相似文献