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161.
Measurements of the equation of state of deuterium at the fluid insulator-metal transition 总被引:1,自引:0,他引:1
GW Collins Da Silva LB P Celliers DM Gold ME Foord RJ Wallace A Ng SV Weber KS Budil R Cauble 《Science (New York, N.Y.)》1998,281(5380):1178-1181
A high-intensity laser was used to shock-compress liquid deuterium to pressures from 22 to 340 gigapascals. In this regime deuterium is predicted to transform from an insulating molecular fluid to an atomic metallic fluid. Shock densities and pressures, determined by radiography, revealed an increase in compressibility near 100 gigapascals indicative of such a transition. Velocity interferometry measurements, obtained by reflecting a laser probe directly off the shock front in flight, demonstrated that deuterium shocked above 55 gigapascals has an electrical conductivity characteristic of a liquid metal and independently confirmed the radiography. 相似文献
162.
S C Baird J Carman R P Dinsmore R L Walker J K Collins 《Journal of veterinary diagnostic investigation》1999,11(5):432-435
A polymerase chain reaction (PCR) test was compared with culture for the detection and diagnosis of bovine Mycoplasma intramammary infection. The PCR test was applied to 24-hour Mycoplasma enrichment cultures of milk from cows with suspected mastitis and from bulk tank milk. In comparison to culture, the sensitivity and specificity of the PCR method were 96.2% and 99.1% for individual cow milk and 100% and 99.8% for the bulk tank milk, respectively. However, in discrepant cases where PCR was positive and culture was negative, the PCR test was correct; subsequent PCR tests and culturing of the individual cow's milk yielded positive results. The PCR test simultaneously detected and differentiated among 11 bovine Mycoplasma species. 相似文献
163.
D. E. Walling A. L. Collins H. M. Sichingabula G. J. L. Leeks 《Land Degradation \u0026amp; Development》2001,12(5):387-415
In many developing countries, the management of sediment‐related environmental problems is severely hampered by a lack of information on sediment mobilization and delivery in river basins. The sediment budget concept represents a valuable framework for assembling such information, which can, in turn, be used to assist with the design and implementation of soil erosion and sediment control policies. However, the information necessary to construct a catchment sediment budget is difficult to assemble. Against this background, an integrated approach to establishing a catchment suspended sediment budget, involving a river monitoring station, the use of 137Cs measurements to estimate soil erosion and deposition and floodplain accumulation rates within the catchment, and sediment source fingerprinting, has been developed and tested in the 63 km2 catchment of the upper Kaleya River in southern Zambia. The approach developed not only provides detailed information on individual components of the suspended sediment delivery system, but also permits the establishment of the overall catchment sediment budget. A sediment budget for the upper Kaleya catchment is presented and both its key features and its wider implications for catchment management are discussed. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
164.
165.
Effect of repeated exposure to AQUI‐S® on the viability and growth of Neoparamoeba perurans
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There have been recent efforts amongst immunologists to develop approaches for following individual fish during challenges with viral and bacterial pathogens. This study contributes to assessing the feasibility of using such approaches to study amoebic gill disease (AGD). Neoparamoeba perurans, agent of AGD, has been responsible for widespread economic and fish loss in salmonid aquaculture. With the emergence of AGD in Europe, research into infection dynamics and host response has increased. This study investigated the effect of repeat exposure to anaesthesia, a necessary requirement when following disease progression in individual fish, on N. perurans. In vitro cultures of N. perurans were exposed every 4 days over a 28‐day period to AQUI‐S® (isoeugenol), a popular anaesthetic choice for AGD challenges, at a concentration and duration required to sedate post‐smolt salmonids. Population growth was measured by sequential counts of amoeba over the period, while viability of non‐attached amoeba in the culture was assessed with a vital stain. AQUI‐S® was found to be a suitable choice for in vivo ectoparasitic challenges with N. perurans during which repetitive anaesthesia is required for analysis of disease progression. 相似文献
166.
Derek M. Anderson Margaret J. MacPherson Stephanie A. Collins Paul F. MacIsaac 《Journal Of Applied Aquaculture》2018,30(2):187-195
Rainbow trout (initial body weight 2.5 ± 0.3 g; 30 fish/tank; 4 tanks/treatment) were offered either the control diet or one of four test diets. The test diets contained brown seed coat canola (BSC; Brassica napus), yellow seed coat canola (YSC; Brassica rapa), Brassica carinata (Ethiopian mustard; EM), or Camelina sativa (CAM), which were added to their respective diets at a 15% dietary inclusion level. Final weight of fish fed the control (101.0 g) was higher than that of fish fed BSC (80.7 g) and CAM (85.3 g) (P < 0.05). Fish fed the control also gained more weight (98.4g) than fish fed BSC (78.2 g) and CAM (83.0 g) (P < 0.05). Fish fed YSC and EM at a 15% dietary inclusion level had a final body weight and gain that was more similar to the control than fish fed BSC and CAM. Considering the fact that there was no significant difference among treatments for SGR and FCR for the entirety of the trial, all four oilseeds have potential for use in rainbow trout feeds. 相似文献
167.
Arnold S. Parco Mavir C. Avellaneda Anna H. Hale Jeffrey W. Hoy Collins A. Kimbeng Michael J. Pontif Kenneth A. Gravois Niranjan Baisakh 《Plant Breeding》2014,133(5):654-659
Brown rust, caused by the fungus Puccinia melanocephala, poses an increasing threat to sugarcane industries worldwide. Recently, markers R12H16 and 9020‐F4 were developed for a major resistance gene Bru1 that contributes to a significant proportion of brown rust resistance in multiple sugarcane industries. Marker‐assisted screening of Louisiana sugarcane germplasm showed a low frequency (4.3%, five out of 117 clones) of Bru1 among sugarcane cultivars and elite breeding clones. Likewise, among progeny of crosses involving wild/exotic germplasm, only 14 of 208 clones (6.7%) tested Bru1 positive. However, Bru1 frequency was higher (28.7%, 52 of 181 clones) in wild/exotic germplasm, which indicated that diverse genetic resources are available for Bru1 introgression. Commercial Bru1‐positive cultivar, ‘L 01‐299', was resistant to brown rust. However, Bru1‐positive cultivar, ‘L 10‐146’, was susceptible while Bru1‐negative cultivars, such as ‘L 99‐233’, showed resistance to brown rust. Bru1‐negative clones with brown rust resistance offer an opportunity to identify alternate sources of resistance, which can be pyramided with Bru1 for effective and durable resistance in sugarcane against the changing pathogen. 相似文献
168.
Jeremy M. Schefers James E. Collins Sagar M. Goyal Trevor R. Ames 《The Canadian veterinary journal. La revue veterinaire canadienne》2009,50(10):1075-1079
Detection, genetic characterization, and control of bovine viral diarrhea virus (BVDV) disease in a large commercial dairy herd is reported. Precolostral BVDV serum antibody was detected in 5.3% (12/226) of newborn calves before the test and removal of persistently infected (PI) animals and in 0.4% (2/450) of newborn calves after the removal of PI heifers. 相似文献
169.
Proliferative enteropathy (PE) is an enteric disease of pigs that results in diarrhoea, reduced growth rate, reduced feed conversion efficiency and sometimes death. A survey of 13 pig veterinary practitioners in Australia was conducted to determine: (1) PE control strategies (antibiotics and vaccination), (2) how the efficacies of these strategies are evaluated and (3) how reliance on antibiotics could be reduced by increasing vaccine adoption. Antibiotics were routinely prescribed in the diets of weaner, grower and finisher pigs by 9/13, 10/13 and 8/13 veterinarians, respectively, if vaccination was not implemented. Water-soluble antibiotics were prescribed less frequently than in-feed antibiotics. Efficacy of control strategies was assessed most often through reduced clinical signs (diarrhoea, 'tail-ender' pigs, death) and reduced lesion incidence at abattoir postmortem inspection. Twelve practitioners had recommended PE vaccination to their clients in the previous 6 months. Barriers to continued vaccine implementation included perceived lack of efficacy for pigs housed in bedded systems, high cost relative to medication and difficulties in vaccinating pigs post-weaning. 相似文献
170.
Sreedhar Alwala Collins A. Kimbeng John C. Veremis Kenneth A. Gravois 《Euphytica》2009,167(1):127-142
The cultivated sugarcane (Saccharum spp. hybrids, 2n = 100–130) is one crop for which interspecific hybridization involving wild germplasm has provided a major breakthrough in
its improvement. Few clones were used in the initial hybridization event leading to a narrow genetic base for continued cultivar
development. Molecular breeding would facilitate the identification and introgression of novel alleles/genes from the wild
germplasm into cultivated sugarcane. We report the identification of molecular markers associated with sugar-related traits
using an F1 population derived from a cross between S. officinarum ‘Louisiana Striped’ × S. spontaneum ‘SES 147B’, the two major progenitor species of cultivated sugarcane. Genetic linkage maps of the S. officinarum and S. spontaneum parents were produced using the AFLP, SRAP and TRAP molecular marker techniques. The mapping population was evaluated for
sugar-related traits namely, Brix (B) and pol (P) at the early (E) and late (L) plant growing season in the plant cane (04)
and first ratoon (05) crops (04EB, 04LB, 04LP, 05EB and 05EP). For S. officinarum, combined across all the traits, a total of 30 putative QTLs was observed with LOD scores ranging from 2.51 to 7.48. The
phenotypic variation (adj. R2) explained by all QTLs per trait ranged from 22.1% (04LP) to 48.4% (04EB). For S. spontaneum, a total of 11 putative QTLs was observed with LOD scores ranging from 2.62 to 4.70 and adj. R2 ranging from 9.3% (04LP) to 43.0% (04LB). Nine digenic interactions (iQTL) were observed in S. officinarum whereas only three were observed in S. spontaneum. About half of the QTLs contributed by both progenitor species were associated with effects on the trait that was contrary
to expectations based on the phenotype of the parent contributing the allele. Quantitative trait loci and their associated
effects were consistent across crop-years and growing seasons with very few QTLs being unique to the early season. When the
data were reanalyzed using the non-parametric discriminant analysis (DA) approach, significant marker-trait associations were
detected for markers that were either identical to or in the vicinity of markers previously identified using the traditional
QTL approach. Discriminant analysis also pointed to previously unidentified markers some of which remained unlinked on the
map. These preliminary results suggest that DA could be used as a complementary approach to traditional QTL analysis in a
crop like sugarcane for which saturated linkage maps are unavailable or difficult to obtain. 相似文献