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101.
102.
Norm M. Good Michelle Paterson Cris Brack Kerrie Mengersen 《Journal of Agricultural, Biological & Environmental Statistics》2001,6(2):258-267
As a signatory to the Kyoto Protocol, Australia is obliged to stabilize greenhouse gas emissions at 8% above 1990 levels by 2008–2012. To demonstrate achievement of this goal, Australia requires national annual estimates of changes in vegetation biomass as greenhouse gas emissions from land use change. These emission estimates are, however, uncertain due largely to the scarcity of existing allometric equations for calculating biomass. The large investment of time and funding required for harvesting, particularly using traditional techniques such as double regression and ratio sampling, also precludes the generation of new equations. Alternative techniques for rapid, cost-effective, and reliable estimation of biomass therefore require investigation. This study, conducted in central Queensland, compared estimates of component biomass that were generated for seven trees of the woodland species Eucalyptus populnea (poplar box) using ratio sampling and variable probability sampling techniques, namely randomized branch sampling (RBS) and RBS with importance sampling (IS). Application of randomized branch sampling consistently underestimated the biomass of leaf and small branches (<1 cm in diameter) and produced weak prediction equations. In contrast, results suggest that RBS with IS is particularly useful in predicting woody (trunk and branches >1 cm in diameter) biomass, and prediction equations agreed with existing equations for this species. However, this method tended to overestimate individual tree woody biomass. The study concluded that RBS with IS was a viable alternative to current methods. 相似文献
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Milk samples from 22 nursing mothers in the metropolitan area of Perth, Western Australia, have shown the presence of DDT, DDE, dieldrin, and HCB in amounts consistent with similar surveys in other countries. Although mean values tend to be slightly lower than expected, their wide range, 0.002-0.025 ppm for DDT, suggests that a much larger sample should be examined to obtain a more accurate mean. This view is supported by values obtained in another survey of the same area. 相似文献
105.
Margaret Abat Michael J. McLaughlin Samuel P. Stacey Jason K. Kirby 《Journal of plant nutrition》2013,36(10):1590-1604
We assessed the response of the tomato variety “Tiny Tom” to the application of copper (Cu) and zinc (Zn) fertilizers in three tropical peat soils of Sarawak: mixed swamp forest, Alan forest and Padang Alan forest. Limed soils were used because peat soils in their natural condition are unsuitable to sustain healthy growth of most crops. Yield responses were correlated with added Cu and Zn using Mitscherlich model. Adequate levels of applied Cu and Zn were calculated as those which resulted in 90% of the maximum obtainable shoot dry weight. Application of Cu and Zn significantly (P ≤ 0.05) increased the shoot dry weight and the shoot Cu and Zn concentrations of tomato. Application of the equivalent of 8.3 kg Cu and 5.2 kg Zn per ha was required to achieve 90% of the maximum shoot dry weight. In tomato shoots, the critical concentration for Cu was 18 mg/kg and for Zn, 92 mg/kg. The corresponding concentrations for diethylenetriaminepentaaceticacid (DTPA) extractable Cu and Zn in the soils were 2.3 mg Cu kg ?1 and 3.6 mg Zn kg ?1 . However, the addition of Cu fertilizer also increased Zn uptake by tomato plant, probably by displacing native Zn that was weakly sorbed to the soil solid phase. 相似文献
106.
The effects of exposure of susceptible alpacas to alpacas persistently infected with bovine viral diarrhea virus 总被引:1,自引:0,他引:1
Byers SR Evermann JF Bradway DS Grimm AL Ridpath JF Parish SM Tibary A Barrington GM 《The Canadian veterinary journal. La revue veterinaire canadienne》2011,52(3):263-271
Reports of bovine viral diarrhea virus (BVDV) infections in alpacas have been increasing in recent years but much is still unknown about the mechanisms of disease in this species. This report characterizes the transmission of BVDV from persistently infected (PI) alpacas to BVDV naïve alpacas, documents shedding patterns, and characterizes the disease effects in both PI and transiently infected alpacas. Two PI alpacas shed BVDV Type 1b virus in most body fluids, and commonly available diagnostic tests verified their status. Bovine viral diarrhea virus Type 1b transient infections produced only mild signs of disease in BVDV naïve alpacas. Viremia was detected in whole blood, but viral shedding during the acute phase was not detected and antibody appeared to be protective upon re-exposure to the virus. 相似文献
107.
The effect of GTPase activating protein upon ras is inhibited by mitogenically responsive lipids 总被引:28,自引:0,他引:28
Bacterially synthesized c-Ha-ras protein (Ras) was incubated with guanosine triphosphatase (GTPase) activating (GA) protein in the presence of various phospholipids. The stimulation of Ras GTPase activity by GA protein was inhibited in some cases. Among the lipids most active in blocking GA protein activity were lipids that show altered metabolism during mitogenic stimulation. These included phosphatidic acid (containing arachidonic acid), phosphatidylinositol phosphates, and arachidonic acid. Other lipids, including phosphatidic acid with long, saturated side chains, diacylglycerols, and many other common phospholipids, were unable to alter GA protein activity. The interaction of lipids with GA protein might be important in the regulation of Ras activity during mitogenic stimulation. 相似文献
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Spatial distribution maps depicting the concentrations of antimony, lead, tin, copper and zinc, and the presence of land-use
units were generated for Mühlburg, a district of the City of Karlsruhe, Germany. The influence of the spatial land-use structure
on the distributions of the element concentrations is statistically evaluated and discussed. The variography for Mühlburg
shows an average range of 200-400 m for the spatial correlations of Sb, Pb, Sn and Zn. The variograms of Pb and Zn are characterised
by hole effects at 300 m distances, i.e. the result of repeated stronger spatial correlations for certain distances between
the sample sites. Most probably, this is an effect of the typical urban structure of streets, buildings, green spaces, and
industry. Kriging method was used for the interpolation of Sb, Pb, Sn and Zn concentrations. Only Cu does not show a spatial
correlation. In this case, the interpolation was carried out with a smoothed triangulation routine. Pollution plumes of point
sources such as lead works, a bell foundry and a coal-fired thermal power station superimpose the more diffuse pollution from
traffic, household heating processes, waste material disposal, etc. The trace element concentrations in soils of housing areas
increase with the age of the developed area. Industrial areas show the highest level of pollution, followed by housing areas
developed before 1920, traffic areas, allotments, housing areas developed between 1920 and 1980, parks and sports areas, cemetery
and housing areas developed after 1980.
It is demonstrated that spatial distribution maps of element concentrations indicate potential emission sources of harmful
substances, even if the emission itself or the direct surrounding soil have not been analysed. The analytical tools presented
enable town planners to discern areas of higher soil pollution. Detailed investigations can be focussed on these areas to
evaluate the possibilities of soil usage and transfer. These methods enable one to manage urban soil in an adequate manner.
For these reasons, the methods demonstrated support an urban environmental impact assessment and are a part of a sustainable
urban soil management. 相似文献