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151.
Old-growth forests can accumulate carbon in soils 总被引:4,自引:0,他引:4
Old-growth forests have traditionally been considered negligible as carbon sinks because carbon uptake has been thought to be balanced by respiration. We show that the top 20-centimeter soil layer in preserved old-growth forests in southern China accumulated atmospheric carbon at an unexpectedly high average rate of 0.61 megagrams of carbon hectare-1 year-1 from 1979 to 2003. This study suggests that the carbon cycle processes in the belowground system of these forests are changing in response to the changing environment. The result directly challenges the prevailing belief in ecosystem ecology regarding carbon budget in old-growth forests and supports the establishment of a new, nonequilibrium conceptual framework to study soil carbon dynamics. 相似文献
152.
众所周知,我国是一个农业大国,随着我国市场经济体制的不断发展与完善,科学技术的不断发展创新,我国人民的生活水平也有较大幅度的提高,农业作为我国的第一产业,在我国的经济发展和社会发展中发挥着十分重要、不可替代的作用,如何将农业发展与科学技术进行有机的结合,实现我国农业的现代化发展,受到了国家和政府前所未有的关注,而农业机械化作为我国农业是否能够实现现代化发展的重要依据,如何更好的、更快的推进我国农业机械化发展的进程,成为我国农业现代化发展过程中不容忽视的关键环节。 相似文献
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以重庆市石柱县黄连中药材种植基地黄连叶片炭疽病病样为试材,通过病原菌分离、致病性测定、形态学特征结合ITS、GADPH、CHS-1和ACT基因序列分析的方法对引起该病的病原进行鉴定,采用菌丝生长速率法测定了5种杀菌剂对病原菌的室内抑菌效果.结果表明:引起重庆市石柱县黄连中药材种植基地黄连叶片炭疽病病原为博宁炭疽菌(Co... 相似文献
155.
以万科上海假日风景,深圳东海岸、17英里、万科城及南昌万科四季花城为考察对象,重点分析了上述住区项目环境设计和建设情况,并提出了住区园林设计和建设的建议。 相似文献
156.
H3PW12O40Ti(OH)4 hydrogel was prepared by the sol-gel method, and then H3PW12O40TiO2/bentonite was prepared through the intercalation of H3PW12O40Ti(OH)4 into interlayer space. The characterization of XRD, SEM and EDS showed that H3PW12O40TiO2 species were successfully immobilized on bentonite, and the layer strucure of bentonite was changed. The discrete anatase TiO2 existed on the bentonite. H3PW12O40TiO2/bentonite was a composite material with the different particle size and th loose structure. The photocatalytic degradation of methyl orange showed that the photocatalytic activity of catalyst had been better by doping H3PW12O40, and the H3PW12O40/TiO2/bentonite had a wide applicable range of pH value. Moreover, H3PW12O40TiO2/bentonite had a good catalytic stability. Based on the results of characterization analysis and catalytic performance, the schematic procedure for the action mechanism of H3PW12O40TiO2/Bentonite in photocatalysis was presented. 相似文献
157.
Bon-Sang Koo Hae-Rim Lee Eun-Ok Jeon Hye-Sun Jang Moo-Sung Han In-Pil Mo 《Journal of veterinary science (Suw?n-si, Korea)》2013,14(2):231-233
A molecular study of intestinal samples from 21 broiler flocks with a history of enteritis revealed that 23.8% and 14.3% were positive for chicken astrovirus (CAstV) and avian rotavirus (ARV), respectively. CAstV and group A ARV were simultaneously detected in only one broiler flock. Birds in this group developed the significant intestinal lesions characterized by frothy contents, paleness, and thin intestinal walls. In this report we present an unusual case of runting stunting syndrome (RSS) with a history of high mortality and growth retardation in broiler chickens. We also make the first identification of CAstV and group A ARV in broiler chickens in Korea. 相似文献
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Sophy A. Jesty Seung Woo Jung Jonathan M. Cordeiro Teresa M. Gunn José M. Di Diego Shari Hemsley Bruce G. Kornreich Giles Hooker Charles Antzelevitch N. Sydney Moïse 《Journal of Veterinary Cardiology》2013,15(1):5-14
ObjectiveTo further characterize arrhythmic mechanisms in German shepherd dogs (GSDs) affected with inherited ventricular arrhythmias by evaluating intracellular calcium cycling and expression of calcium handling genes.AnimalsTwenty five GSDs, 9 backcross dogs, and 6 normal mongrel dogs (controls) were studied. The GSDs and backcross dogs were from a research colony of inherited ventricular arrhythmias. The control research dogs were purchased.MethodsAction potentials (APs) and pseudo-electrocardiograms (ECG) were recorded from left ventricular (LV) wedge preparations of GSDs and normal dogs. Midmyocardial (Mid) LV cells from GSDs and normal mongrels were isolated by enzymatic digestion. Cells were either field stimulated or voltage clamped and calcium transients were measured by confocal microscopy using the indicator Fluo-3AM. Expression of calcium handling genes was measured by quantitative RT-PCR.ResultsMean calcium transient decay (tau) was not different between affected GSDs and control dogs, but striking cell-to-cell variability for tau was observed within affected GSDs and between affected GSDs and controls (P < 0.0001 each); within-dog variability accounted for 75% of total variability. Calcium sparks and afterdepolarizations occurred in GSD but not control cells. ATP2A2/SERCA2a expression was significantly reduced (P = 0.0063) in affected GSDs and inversely correlated (P = 0.0006) with severity of ventricular arrhythmias.ConclusionsGerman shepherd dogs with inherited ventricular arrhythmias have electrophysiologic abnormalities in calcium cycling associated with reduced ATP2A2/SERCA2a expression. These animals provide a unique opportunity to study calcium remodeling at the genetic and molecular level in familial ventricular arrhythmias. 相似文献