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“山水林田湖草沙生命共同体”系统保护与修复是我国生态文明建设的重要内容。明确生命共同体的耦合机制,是科学地进行生态保护和修复工作的关键。针对当前生命共同体耦合机制不清、理论和方法不健全的问题,从耦合的视角出发,在小流域尺度上单一生态系统内部生态要素的耦合、流域尺度上不同生态系统之间的耦合、区域尺度上人与自然的耦合三个方面进行整合,在此基础上探讨了多尺度山水林田湖草沙耦合理论,提出了一般性的山水林田湖草沙耦合理论框架。梳理并比较了当前主要的生态系统模型、景观模型、统计学模型以及复合生态系统的多模型耦合方法,综合提出了一个适用于"山水林田湖草沙生命共同体"耦合研究方法。对进一步完善山水林田湖草沙一体化保护修复提出了建议,包括:一是构建多源信息数据库,推进定量化耦合机制研究;二是开展全生命周期监测与评估,探索适应性治理路径;三是强化多元主体参与,完善协同保护机制。 相似文献
154.
PCR-based assays of mendelian polymorphisms from anonymous single-copy nuclear DNA: techniques and applications for population genetics 总被引:5,自引:0,他引:5
This paper outlines a PCR-based approach for population genetics that
offers several advantages over conventional Southern blotting methods for
revealing restriction-fragment-length polymorphisms (RFLPs) in nuclear DNA.
Primers are constructed from clones isolated from a nuclear DNA library,
and these primers subsequently are employed in in vitro syntheses of
homologous regions. Amplified products are then screened directly for RFLPs
by using gel-staining procedures. Population applications for this
PCR-based approach, including potential strengths and weaknesses, are
exemplified by two RFLP data sets generated to estimate (a) male-mediated
gene flow in the green turtle (Chelonia mydas) and (b) geographic
population genetic structure in the American oyster (Crassostrea
virginica). Restriction assays of amplified products from 14 or 15
independent primer pairs in each species revealed polymorphisms at several
loci that proved highly informative in the population genetic analyses. In
general, the Mendelian polymorphisms produced by this PCR-based approach
will provide useful genetic markers for population studies, particularly in
situations where simpler and less expensive allozyme methods have failed,
for whatever reason, to provide adequate information.
相似文献
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158.
Donald SA McLeod 《The Clinical biochemist. Reviews / Australian Association of Clinical Biochemists》2010,31(1):9-19
This paper provides an overview on the biology, monitoring and management of differentiated thyroid cancer (DTC), with particular attention to issues of relevance to clinical chemistry. The incidence of DTC appears to be increasing and management strategies are evolving as we learn more about its natural history and response to therapy. Clinical chemistry techniques play a central role in these protocols. Technical limitations inherent in current monitoring tools can hamper follow-up, although progress is being made. The molecular basis of DTC is being delineated with the potential to develop new strategies for diagnosis, monitoring and management of this condition. 相似文献
159.
Several fundamental questions remain enigmatic concerning human olfactory
sensitivity, including (i) whether detection threshold differences exist
between the two sides of the nose (and, if so, whether such differences are
influenced by handedness) and (ii) whether bilateral (i.e. binasal)
stimulation leads to lower thresholds than unilateral stimulation (and, if
so, whether the degree of facilitation is inversely related to general
olfactory ability). In this study, and well-validated single staircase
procedure was used to establish bilateral and unilateral detection
thresholds for the cranial nerve I stimulant phenyl ethyl alcohol in 130
right- and 33 left-handed subjects. No differences in sensitivity between
the left and right sides of the nose were observed in either group.
Bilateral thresholds were lower, on average, than unilateral thresholds
when the latter were categorized in terms of left and right nares. However,
the bilateral thresholds did not differ significantly from those of the
side of the nose with the lower threshold. Overall smell ability, as
measured by the University of Pennsylvania Smell Identification Test, did
not interact with any of the test measures. These data imply that (i) the
left and right sides of the nose do not systematically differ in detection
threshold sensitivity for either dextrals or sinistrals and (ii) if central
integration of left:right olfactory threshold sensitivity occurs, its
effects do not exceed the function of the better side of the nose.
相似文献
160.
Ophioglossum yongrenense Ching ex Z. R. He et W. M. Chu, sp. nov.Species nova aspectu inter O. kawamuram Tagawa et O. parvum Nishida et Kurita Japonicae, differt a priore frondibus pro parte laminis sterilibus praeditis (in illa frondibus omnino laminis sterilibus non praeditis), a posteriore frondibus pro parte laminis sterilibus non praeditis (in O. parvo Nishida et Kurita frondibus omino laminis sterilibus praeditis).…… 相似文献