Microorganisms in the accreted ice of Lake Vostok, Antarctica     

Karl DM  Bird DF  Björkman K  Houlihan T  Shackelford R  Tupas L 《Science (New York, N.Y.)》1999,286(5447):2144-2147

Analysis of a portion of Vostok ice core number 5G, which is thought to contain frozen water derived from Lake Vostok, Antarctica (a body of liquid water located beneath about 4 kilometers of glacial ice), revealed between 2 x 10(2) and 3 x 10(2) bacterial cells per milliliter and low concentrations of potential growth nutrients. Lipopolysaccharide (a Gram-negative bacterial cell biomarker) was also detected at concentrations consistent with the cell enumeration data, which suggests a predominance of Gram-negative bacteria. At least a portion of the microbial assemblage was viable, as determined by the respiration of carbon-14-labeled acetate and glucose substrates during incubations at 3 degrees C and 1 atmosphere. These accreted ice data suggest that Lake Vostok may contain viable microorganisms.  相似文献   

Outburst of Jupiter's synchrotron radiation after the impact of comet Shoemaker-Levy 9     

de Pater I  Heiles C  Wong M  Maddalena RJ  Bird MK  Funke O  Neidhoefer J  Price RM  Kesteven M  Calabretta M  Klein MJ  Gulkis S  Bolton SJ  Foster RS  Sukumar S  Strom RG  LePoole RS  Spoelstra T  Robison M  Hunstead RW  Campbell-Wilson D  Ye T  Dulk G  Leblanc Y  Lecacheux A 《Science (New York, N.Y.)》1995,268(5219):1879-1883

Jupiter's nonthermal microwave emission, as measured by a global network of 11 radio telescopes, increased dramatically during the Shoemaker-Levy 9 impacts. The increase was wavelength-dependent, varying from approximately 10 percent at 70 to 90 centimeters to approximately 45 percent at 6 and 36 centimeters. The radio spectrum hardened (flattened toward shorter wavelengths) considerably during the week of impacts and continued to harden afterward. After the week of cometary impacts, the flux density began to subside at all wavelengths and was still declining 3 months later. Very Large Array and Australia Telescope images of the brightness distribution showed the enhancement to be localized in longitude and concentrated near the magnetic equator. The evidence therefore suggests that the increase in flux density was caused by a change in the resident particle population, for example, through an energization or spatial redistribution of the emitting particles.  相似文献   

The joint action of nitrogen and nematicides onPratylenchus penetrans and potato yield     

M. L. Vitosh  J. W. Noling  G. W. Bird  R. W. Chase 《American Journal of Potato Research》1980,57(3):101-111

The joint action of nitrogen fertilizer and nematicides onPratylenchus penetrons and yield was investigated using three potato varieties (Superior, Onaway and Russet Burbank), three rates of nitrogen (84, 168 and 336 kg/ha), five edaphic pesticides (disulfoton, aldicarb, 1,3-D + MIC, carbofuran and thiofanox), and an insecticide spray to minimize the role of foliar feeding insects In 1977, disulfoton, aldicarb, and disulfoton plus 1,3-D + MIC significantly increased the yield of Superior at all nitrogen rates. The yield increases ranged from 37–56% for Superior, 15–35% for Onaway and 13–27% for Russet Burbank. Nitrogen had no detectable influence on yield. Population densities ofP. penetrans were significantly reduced by disulfoton plus 1,3-D + MIC and by aldicarb. Superior was most susceptible toP. penetrans, Onaway intermediate, and Russet Burbank moderately tolerant. Neither the potato variety or nitrogen significantly influenced the population densities ofP. penetrans In 1978 aldicarb, 1,3-D + MIC and thiofanox significantly increased yields of Superior at all nitrogen rates. Nitrogen also significantly increased yields, but only where aldicarb and 1,3-D + MIC were applied. Total yield was increased 12–14% and 17–23% by 1,3-D + MIC and aldicarb at 168 and 336 kg N/ha, respectively. Aldicarb, 1,3-D + MIC, and thiofanox appeared to increase tuber set, while nitrogen increased tuber size. Although all of the nematicides provided some control ofP. penetrans, aldicarb had the highest degree of efficacy and gave excellent season-long control  相似文献   

The design of porous material sensors to measure the matric potential of water in soil     

W. R. Whalley  C. W. Watts  M. A. Hilhorst  N. R. A. Bird  J. Balendonck  & D. J. Longstaff 《European Journal of Soil Science》2001,52(3):511-519

In recent years the use of porous material sensors for matric potential, which were originally intended for soil drier than ?100 kPa, has been extended to wet soils. In these wetter soils, unpredictable behaviour of the sensors has been reported. We have studied the design of porous material sensors of matric potential in soil and propose a hypothesis to explain this unpredictability, and suggest recommendations for a design of sensor which will behave more reliably. The development of an experimental porous material sensor of matric potential based on this design is described. It operates between 0 and ?60 kPa, and both the drying and wetting moisture characteristics were measured. In this sensor the porous material was a ceramic and its water content was measured with a dielectric water content sensor. We tested a simple closed‐form hysteresis model to convert the measured water content of the porous material into matric potential under laboratory conditions. This was shown to give better results than using a calibration based on the drying moisture characteristic curve, where the predicted matric potentials were too small. The use of the experimental sensors in the field environment is described. Both types of sensor were installed using the same procedure. As far as we are aware the experimental sensor described in this paper is the first porous material sensor of matric potential that can be installed in the same way as a conventional tensiometer. Both conventional tensiometers and the experimental porous material sensors gave similar estimates of matric potential.  相似文献   

Impact of Microwaves and Water On Acoustical Signatures of Yard And Kitchen Refuse Compost     

M. Quintanilla Tornel  G. Bird  S. Gage 《Compost science & utilization》2013,21(3):140-144

Acoustical technologies have been used to evaluate characteristics of ecosystems, including soil, demographics and organism behavior. In our research, the acoustics of four states of yard and kitchen refuse compost were analyzed. These included: compost with and without water, and microwaved compost with and without water. The acoustics generated by the microwaved and non-microwaved composts were recorded in a sound chamber. Water was then added to the control and microwaved samples. Subsequently, the acoustics were recorded again. Sonograms were produced for each of the four treatments and the data analyzed in relation to sound Power Spectral Density (PSD). With the addition of water, the nonmicrowaved compost became acoustically active. The PSD was more than five times greater (p < 0.0001, ANOVA repeated measures) than the microwaved compost with and without water and the non-microwaved compost without water. Most of the PSD for all four treatments was in the lower kHz frequency levels (1-4). KHz frequency level one contained the majority of the sound. Compost plus water, had significantly more PSD at kHz level 1 than the sum of kHz levels 2-11. Most of the remaining PSD was found in the lower kHz frequencies. It is concluded that: 1) compost can be considered as a place where organisms are often dormant, and 2) compost can be activated with water used as a pulsing agent.  相似文献   

Rift Valley fever virus(Bunyaviridae: Phlebovirus): an update on pathogenesis, molecular epidemiology, vectors, diagnostics and prevention     

Pepin M  Bouloy M  Bird BH  Kemp A  Paweska J 《Veterinary research》2010,41(6):61-Dec;41(6):61

Rift Valley fever(RVF) virus is an arbovirus in the Bunyaviridae family that, from phylogenetic analysis, appears to have first emerged in the mid-19th century and was only identified at the beginning of the 1930's in the Rift Valley region of Kenya. Despite being an arbovirus with a relatively simple but temporally and geographically stable genome, this zoonotic virus has already demonstrated a real capacity for emerging in new territories, as exemplified by the outbreaks in Egypt (1977), Western Africa (1988) and the Arabian Peninsula (2000), or for re-emerging after long periods of silence as observed very recently in Kenya and South Africa. The presence of competent vectors in countries previously free of RVF, the high viral titres in viraemic animals and the global changes in climate, travel and trade all contribute to make this virus a threat that must not be neglected as the consequences of RVF are dramatic, both for human and animal health. In this review, we present the latest advances in RVF virus research. In spite of this renewed interest, aspects of the epidemiology of RVF virus are still not fully understood and safe, effective vaccines are still not freely available for protecting humans and livestock against the dramatic consequences of this virus.  相似文献   

Linkage mapping an indoxacarb resistance locus in Helicoverpa armigera (Lepidoptera: Noctuidae) by genotype‐by‐sequencing     

Yizhou Chen  Lisa Bird  Lauren Woolley  Tom Walsh  Karl Gordon  Grant Herron 《Pest management science》2020,76(2):617-627

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Tree windbreaks and shelter benefits to pasture in temperate grazing systems     

P. R. Bird 《Agroforestry Systems》1998,42(2):211-211

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The fine structure of cysts of Frenkelia (the M-organism)     

W A Tadros  R G Bird  D S Ellis 《Folia parasitologica》1972,19(3):203-209

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Serology of Campylobacter fetus fetus strains from four outbreaks of ovine abortion     

Bird MM  Stephens DJ  Wall EP  de Lisle GW 《New Zealand veterinary journal》1984,32(1-2):14-17

As a result of a Ministry of Agriculture & Fisheries survey on ovine abortions, 76 isolates of Campylobacterfetus fetus were obtained. These isolates were from four farms in the southern Hawkes Bay, with an abortion incidence of 2.8% to 9.1%. Antisera to eight different strains of C. fetus fetus were made in rabbits. Strains were then examined using whole cell tube agglutination tests and sensitised Staphylococcal Protein A slide agglutination tests. Heat labile antigens were examined by absorbing antisera with heat-treated bacteria. Two broad serogroups were found, but within-group variation was demonstrated by cross-absorbing antisera. The isolates from one farm were all of a single broad serogroup. Both serogroups were found on the remaining three farms. Evidence for the presence of two major serogroups was also obtained by immobilisation tests and antigen analysis by gel diffusion.  相似文献