Major compositional units of the moon: lunar prospector thermal and fast neutrons   总被引：2，自引：0，他引：2  

WC Feldman  BL Barraclough  S Maurice  RC Elphic  DJ Lawrence  DR Thomsen  AB Binder 《Science (New York, N.Y.)》1998,281(5382):1489-1493

Global maps of thermal and fast neutron fluxes from the moon suggest three end-member compositional units. A high thermal and low fast neutron flux unit correlates with the lunar highlands and is consistent with feldspathic rocks. The South Pole-Aitken basin and a strip that surrounds the nearside maria have intermediate thermal and fast neutron flux levels, consistent with more mafic rocks. There appears to be a smooth transition between the most mafic and feldspathic compositions, which correspond to low and high surface altitudes, respectively. The maria show low thermal and high fast neutron fluxes, consistent with basaltic rocks.  相似文献   

Platinum catalysts for the high-yield oxidation of methane to a methanol derivative   总被引：1，自引：0，他引：1  

RA Periana  DJ Taube  S Gamble  H Taube  T Satoh  H Fujii 《Science (New York, N.Y.)》1998,280(5363):560-564

Platinum catalysts are reported for the direct, low-temperature, oxidative conversion of methane to a methanol derivative at greater than 70 percent one-pass yield based on methane. The catalysts are platinum complexes derived from the bidiazine ligand family that are stable, active, and selective for the oxidation of a carbon-hydrogen bond of methane to produce methyl esters. Mechanistic studies show that platinum(II) is the most active oxidation state of platinum for reaction with methane, and are consistent with reaction proceeding through carbon-hydrogen bond activation of methane to generate a platinum-methyl intermediate that is oxidized to generate the methyl ester product.  相似文献   

Lunar Fe and Ti abundances: comparison of lunar prospector and clementine data   总被引：3，自引：0，他引：3  

RC Elphic  DJ Lawrence  WC Feldman  BL Barraclough  S Maurice  AB Binder  PG Lucey 《Science (New York, N.Y.)》1998,281(5382):1493-1496

The Lunar Prospector neutron spectrometer data correlate well with iron and titanium abundances obtained through analysis of Clementine spectral reflectance data. With the iron and titanium dependence removed, the neutron spectrometer data also reveal regions with enhanced amounts of gadolinium and samarium, incompatible rare earth elements that are enriched in the final phases of magma crystallization. These regions are found mainly around the ramparts of the Imbrium impact basin but not around the other basins, including the much larger and deeper South Pole-Aitken basin. This result confirms the compositional uniqueness of the surface and interior of the Imbrium region.  相似文献   

Erysipelas in malleefowl     

DJ BLYDE  R WOODS 《Australian veterinary journal》1999,77(7):434-435

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AGE AND DIET EFFECTS ON RELATIVE RENAL ECHOGENICITY IN GERIATRIC BITCHES     

Julie A.  Churchill  Daniel A.  Feeney  Thomas F.  Fletcher  Carl A.  Osborne  David J.  Polzin 《Veterinary radiology & ultrasound》1999,40(6):642-647

Under controlled, but varied dietary conditions 35 geriatric, uninephrectomized, spayed Beagle bitches (dogs) observed for 4 years, renal cortical and renal medullary echogenicity was measured relative to hepatic and splenic echogenicity. Regardless of the diet fed, 60-75% of these aged dogs had renal cortical echogenicity less than that of either the liver or spleen across time; 25-35% of these dogs had renal cortical echogenicity equal to that of the liver, but less than that of the spleen across time. Less than 3% of these dogs had renal cortical echogenicity greater than that of the liver, but less than that of the spleen. Only 1 (one) of these dogs had renal cortical echogenicity equal to that of the spleen and that occurred at only one of the 14 chronologic assessments. Therefore, in either mature or aged dogs imaged with 4.0 to 5.0 MHz equipment, the renal cortical echogenicity should be considered normal if it is less than or equal to that of the liver and less than that of the spleen. In 29 dogs imaged with the 4.0/5.0 MHz equipment and 6 dogs imaged with 7.5 MHz equipment, there was no significant diet or individual dog effect. The 7.5 MHz (6 dog) group had significantly higher average cortical echogenicity scores than the 4.0/5.0 MHz (29 dog) group. However, the occurrence of renal cortical echogenicity greater than liver echogenicity was seen in only 5 of 83 samples (approximately 6.0%) made on 6 dogs imaged with 7.5 MHz equipment and only 1 of 375 samples (approximately 0.27%) made on 29 dogs with 4.0/5.0 MHz equipment. With the exception of one occurrence, all dogs had renal medullary echogenicity less than that of the liver or spleen regardless of imaging equipment frequency. The renal medulla was always hypoechoic compared to the cortex.  相似文献   

Sex ratio changes in the long-term Windermere pike and perch sampling program   总被引：1，自引：1，他引：0  

C. G. M. Paxton  J. M. Fletcher  D. P. Hewitt  I. J. Winfield 《Ecology of Freshwater Fish》1999,8(2):78-84

Abstract– Analysis of the Windermere (England), Perca fluviatilis (1965–1997) and Esox lucius (1943-1997) fishery data indicates there have been substantial changes in sex ratios through time. In the case of perch, a 1976 perch disease outbreak substantially skewed the sex ratio in favor of females. It took over a decade for the fishery to recover to its pre-1976 state. In the case of pike, both catch and year-class data are female biased, but this bias has significantly weakened through time. This trend towards proportionately more males through time may reflect an effect of increasing spring temperatures or an evolutionary or phenotypic response to female-biased fishing pressure.  相似文献   

Larval pigmentation, survival and growth of Penaeus indicus fed the nematode Panagrellus redivivus enriched with astaxanthin and various lipids   总被引：1，自引：0，他引：1  

M. Kumlu  D.J. Fletcher  & C.M. Fisher 《Aquaculture Nutrition》1998,4(3):193-200

The highly unsaturated fatty acid (HUFA) content of the free-living nematode Panagrellus redivivus was successfully increased when three different lipid sources (cod-liver oil, marilla oil and capelin oil) from marine animals were used in the nematode culture medium. The lipid enrichment significantly increased the ω3 HUFA content, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), of the nematodes compared with lipid non-enriched nematodes. Penaeus indicus larvae fed the lipid-enriched nematodes had significantly ( P < 0.05) greater larval survival (69–77%) until metamorphosis than those fed non-enriched nematodes (54%).
This nematode species was also enriched with astaxanthin to determine the effects of this carotenoid on pigmentation, survival and growth during the larval development of P. indicus . The pigment, delivered via nematodes, significantly ( P < 0.05) improved larval coloration and survival (88%) compared with that of placebo-pigmented nematodes (78%). However, there was no strong evidence to show the benefit of either pigment and/or lipid enrichment on larval growth and development of P. indicus .
This study has shown that the nutritional value of the nematodes can be enhanced by the addition of fish oil into the culture medium. Supplementation of EPA and DHA, together with synthetic astaxanthin, allow the nematodes to be used as a sole diet for the larval culture of P. indicus .  相似文献   

Optimum use of available residue data in the estimation of dietary intake of pesticides     

DJ Hamilton  PT Holland  B Ohlin  WJ Murray  A Ambrus  GC de Baptista  J Kovacicova 《Pest management science》1999,55(2):220-221

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Bridging the divide: Social–ecological coherence in Marine Protected Area network design          下载免费PDF全文

Sian E. Rees  Simon J. Pittman  Nicola Foster  Olivia Langmead  Charly Griffiths  Steve Fletcher  David E. Johnson  Martin Attrill 《水产资源保护:海洋与淡水生态系统》2018,28(3):754-763

Development of a Pseudomonas syringae–Eutrema salsugineum pathosystem to investigate disease resistance in a stress tolerant extremophile model plant          下载免费PDF全文

J. Fletcher  M. J. Champigny  E. A. Weretilnyk  R. K. Cameron 《Plant pathology》2015,64(2):297-306

To improve the ability to understand how plants respond to multiple and/or concurrent stresses, disease resistance was investigated in Eutrema salsugineum, an extremophile model plant that is highly tolerant of abiotic stress. Compared to Arabidopsis (Col‐0), both Yukon and Shandong Eutrema accessions exhibit increased resistance to Pseudomonas syringae pv. tomato DC3000 (Pst) and pv. maculicola (Psm), with Shandong Eutrema exhibiting greater resistance to Pst than Yukon Eutrema. RT‐PCR of the EsPR1 (Pathogenesis‐related 1) defence marker gene confirmed RNA‐Seq data that healthy Shandong Eutrema constitutively expresses EsPR1. The data suggests that Shandong Eutrema exists in a highly primed state of defence preparedness, as it displays heightened resistance compared to defence‐primed natural accessions of Arabidopsis (Can‐0, Bur‐0). Pathogen‐triggered PR1 expression was delayed in Yukon Eutrema; however, these plants were resistant to Pst suggesting that Yukon Eutrema employs a PR1‐independent mechanism to resist Pst. This study demonstrates that Eutrema is an excellent model to investigate biotic stress tolerance. The Eutrema–P. syringae pathosystem will facilitate future studies to understand how this extremophile tolerates both abiotic and biotic stress, and will allow exploration of the interplay of these responses to inform efforts to improve stress tolerance in crops.  相似文献