Flood volcanism in the northern high latitudes of Mercury revealed by MESSENGER     

Head JW  Chapman CR  Strom RG  Fassett CI  Denevi BW  Blewett DT  Ernst CM  Watters TR  Solomon SC  Murchie SL  Prockter LM  Chabot NL  Gillis-Davis JJ  Whitten JL  Goudge TA  Baker DM  Hurwitz DM  Ostrach LR  Xiao Z  Merline WJ  Kerber L  Dickson JL  Oberst J  Byrne PK  Klimczak C  Nittler LR 《Science (New York, N.Y.)》2011,333(6051):1853-1856

MESSENGER observations from Mercury orbit reveal that a large contiguous expanse of smooth plains covers much of Mercury's high northern latitudes and occupies more than 6% of the planet's surface area. These plains are smooth, embay other landforms, are distinct in color, show several flow features, and partially or completely bury impact craters, the sizes of which indicate plains thicknesses of more than 1 kilometer and multiple phases of emplacement. These characteristics, as well as associated features, interpreted to have formed by thermal erosion, indicate emplacement in a flood-basalt style, consistent with x-ray spectrometric data indicating surface compositions intermediate between those of basalts and komatiites. The plains formed after the Caloris impact basin, confirming that volcanism was a globally extensive process in Mercury's post-heavy bombardment era.  相似文献   

Molecular Characterization of Atlas 66-Derived Wheat Near-lsogenic Lines Contrasting in Aluminum （Al） Tolerance   总被引：1，自引：0，他引：1  

GUO Pei-guo BAI Gui-hua LI Rong-hua Brett Carver Michael Baum 《中国农业科学(英文版)》2007,6(5):522-528

Aluminum （Al） toxicity is the major limiting factor for wheat growth in acidic soils. Genetic improvement of Al tolerance is one of the most cost-effective solutions to improve wheat productivity. The objective of this study was to characterize near isogenic lines （NILs） contrasting in Al tolerance derived from Atlas 66 in the backgrounds of Al-sensitive cultivars Chisholm and Century using amplified fragment length polymorphism （AFLP） and simple sequence repeat （SSR）. A total of 200 AFLP and 88 SSR primer pairs were screened and 12 markers （11 AFLPs and one SSR） were associated with Al-tolerance in NILs of at least one recurrent parental background. Among them, nine were linked to A1 tolerance in the Chisholm-derived NILs, seven were associated with Al-tolerance in the Century-derived NILs, and three AFLPs derived from the primer combinations of pAG/mGCAG, pCAG/mAGC and pGTG/mGCG, and one SSR, Xwmc331 on chromosome 4D, associated with A1 tolerance in NILs of both recurrent parental backgrounds. Those common markers across two backgrounds may be the major marker loci associated with Al-tolerance in Atlas 66 and could be useful for marker-assisted breeding to improve Al tolerance in wheat. In addition, evaluation of Al tolerance among different genotypes using hematoxylin stain and relative root growth revealed that Atlas 66 was more tolerant to Al stress than the NILs, therefore suggested that the Al-tolerant NILs might not carry all Al-tolerance loci from Arias 66 and inheritance of Al tolerance in Arias 66 is more likely multigenic.  相似文献   

Gosses bluff impact structure, australia     

Milton DJ  Glikson AY  Manwaring EA  Moss FJ  Sedmik EC  Son JV  Barlow BC  Brett R  Young GA 《Science (New York, N.Y.)》1972,175(4027):1199-1207

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Endosomal proteolysis of the Ebola virus glycoprotein is necessary for infection     

Chandran K  Sullivan NJ  Felbor U  Whelan SP  Cunningham JM 《Science (New York, N.Y.)》2005,308(5728):1643-1645

Ebola virus (EboV) causes rapidly fatal hemorrhagic fever in humans and there is currently no effective treatment. We found that the infection of African green monkey kidney (Vero) cells by vesicular stomatitis viruses bearing the EboV glycoprotein (GP) requires the activity of endosomal cysteine proteases. Using selective protease inhibitors and protease-deficient cell lines, we identified an essential role for cathepsin B (CatB) and an accessory role for cathepsin L (CatL) in EboV GP-dependent entry. Biochemical studies demonstrate that CatB and CatL mediate entry by carrying out proteolysis of the EboV GP subunit GP1 and support a multistep mechanism that explains the relative contributions of these enzymes to infection. CatB and CatB/CatL inhibitors diminish the multiplication of infectious EboV-Zaire in cultured cells and may merit investigation as anti-EboV drugs.  相似文献   

Land-Grant Universities and Extension into the 21st Century: Renegotiating or Abandoning a Social Contract. By George R. McDowell     

Nancy Grudens-Schuck  Brett A. Kramer 《Agriculture and Human Values》2003,20(2):205-209

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A QTL for early heading in wheat cultivar Suwon 92     

Xiangyang?Xu  Guihua?BaiEmail author  Brett?F.?Carver  Gregory?E.?Shaner 《Euphytica》2005,146(3):233-237

Heading date is an important trait that determines wheat adaptation to environments. A recombinant inbred line (RIL) population derived from CI 13227 × Suwon 92 was employed to tag the quantitative trait locus (QTL) for early heading in Suwon 92. This population was phenotyped for heading date in 1994, 1995, and 1997, and analyzed with AFLP and SSR markers. Two AFLP markers (XGCTG.CGCT118 and XGCTG.CGCT60) closely associated with heading date were identified. Across years, XGCTG.CGCT118 and XGCTG.CGCT60 explained 40.4% and 32.2% of the total phenotypic variances, respectively. Interval analysis revealed a major QTL for heading date, designated QHd.pser-2DS, between AFLP marker XGCTG.CGCT118 and SSR marker Xgwm261. Based on the linkage map, QHd.pser-2DS was about 41.2 cM proximal to the distal end of chromosome 2DS, and explained 40.5% of the phenotypic variance across three years. The identified markers associated with the early heading QTL have the potential to be used in wheat breeding programs.  相似文献   

Effects of dietary astaxanthin source and light manipulation on the skin colour of Australian snapper Pagrus auratus (Bloch & Schneider, 1801)     

Mark A Booth  Rebecca J Warner-Smith  Geoff L Allan  & Brett D Glencross 《Aquaculture Research》2004,35(5):458-464

Two experiments were conducted with Australian snapper Pagrus auratus (Bloch and Schneider, 1801). The first was aimed at determining the dietary level of astaxanthin that improved skin redness (CIE a^*values) of farm‐reared snapper. Farmed snapper (ca. 600 g) fed a commercial diet without carotenoids were moved to indoor tanks and fed the same diet supplemented with 0, 36 or 72 mg astaxanthin kg^?1 (unesterified form as Carophyll Pink?) for nine weeks. Skin redness (CIE a^* values) continued to decrease over time in fish fed the diet without astaxanthin. Snapper fed the diet containing 72 mg astaxanthin kg^?1 were significantly more red than fish fed the diet with 36 mg astaxanthin kg^?1 three weeks after feeding, but skin redness was similar in both groups of fish after 6 and 9 weeks. The second experiment was designed to investigate the interactive effects of dietary astaxanthin source (unesterified form as Carophyll Pink? or esterified form as NatuRose?; 60 mg astaxanthin kg^?1) and degree of shading (0%, 50% and 95% shading from incident radiation) on skin colour (CIE L^*a^*b^*) and skin and fillet astaxanthin content of farmed snapper (ca. 800 g) held in 1 m³ floating cages. After 116 days, there were no significant interactions between dietary treatment and degree of shading for L^*, a^* or b^* skin colour values or the concentration of astaxanthin in the skin. Negligible amounts of astaxanthin were recovered from fillet samples. The addition of shade covers significantly increased skin lightness (L^*), possibly by reducing the effect of melanism in the skin, but there was no difference between the lightness of fish held under either 50% or 95% shade cover (P>0.05).  相似文献   

Breeding performance of Malaysian mahseer, Tor tambroides and T. douronensis broodfish in captivity     

Brett Ingram  Stephen Sungan  David Tinggi  Sih Yang Sim  & Sena S De Silva 《Aquaculture Research》2007,38(8):809-818

Tor tambroides and T. douronensis are highly valued freshwater cyprinids. Owing to their cultural and economic importance, and concerns over their conservation status, a captive artificial propagation programme was established in Sarawak, Malaysia, to produce seedstock for conservation and aquaculture purposes. This paper describes work that followed the initial breakthrough in artificial propagation of captive, pond‐reared broodfish of the two Tor species, primarily on the overall breeding performance of broodfish over a 3‐year period. Breeding performance generally increased through the study period, indicating an overall improvement in husbandry and breeding techniques since commencing breeding trials. Spawning was induced in most months of the year. Seasonal patterns in spawning performance were not clear, but nevertheless the influence of monsoonal climate patterns was evident as higher breeding performance indicators were observed during the northeast monsoon. Some individual broodfish were injected and stripped up to 11 times during the study, and there were as little as 30 days between successful strippings. Considerable variability was observed in each of the breeding performance indicators with successive hypophysation, although in T. tambroides, there were signs of an increase in some of these indicators with successive hypophysation attempts. Multiple injection of Ovaprim, and repeated stripping of eggs, does not appear to reduce breeding performance, at least for T. tambroides.  相似文献   

Comparison of Phosphorus Use Efficiency Among Various Winter Wheat Accessions Grown in Acid and Calcareous Soils     

Chad J. Penn  Patrick R. Bell  Brett Carver  D. Brian Arnall  Arthur Klatt 《Journal of plant nutrition》2015,38(14):2279-2293

The objective was to differentiate and estimate phosphorus (P)-uptake and P-utilization efficiency among several winter wheat accessions. Twenty-two accessions were characterized for their ability to uptake and utilize P in two low P soils (acid and calcareous). Plants were grown for 28 days in two different sized pots and analyzed for biomass and total P concentration. Total P uptake and biomass was greater in the large pot and calcareous soil. However, there were no significant correlations between the small and large pot for biomass, P uptake, and P concentration, indicating that rooting conditions were different for the two pots, which allowed differentiation between P-utilization and P-uptake efficiency. Possession of ALTM1 gene for malate excretion did not appear to be related to P-uptake efficiency. Several accessions were found to be either P-uptake or P-utilization efficient in both soils. Phosphorus use efficiency mechanisms may contribute to acid soil tolerance.  相似文献   

Survey of vets employed in industry     

Sheridan L  Whelan K 《The Veterinary record》2011,168(20):543-544

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