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1.
Ludwig John A. Eager Robert W. Bastin Gary N. Chewings Vanessa H. Liedloff Adam C. 《Landscape Ecology》2002,17(2):157-171
The cover, number, size, shape, spatial arrangement and orientation of vegetation patches are attributes that have been used
to indicate how well landscapes function to retain, not ‘leak’, vital system resources such as rainwater and soil. We derived
and tested a directional leakiness index (DLI) for this resource retention function. We used simulated landscape maps where
resource flows over map surfaces were directional and where landscape patch attributes were known. Although DLI was most strongly
related to patch cover, it also logically related to patch number, size, shape, arrangement and orientation. If the direction
of resource flow is multi-directional, a variant of DLI, the multi-directional leakiness index (MDLI) can be used. The utility
of DLI and MDLI was demonstrated by applying these indices to three Australian savanna landscapes differing in their remotely
sensed vegetation patch attributes. These leakiness indices clearly positioned these three landscapes along a function-dysfunction
continuum, where dysfunctional landscapes are leaky (poorly retain resources).
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
2.
Dominant sources of dietary carbon and nitrogen for shrimp reared in extensive rice-shrimp ponds 总被引:1,自引:0,他引:1
Michele A Burford Nigel P Preston Truong Hoang Minh Tran Thi Tuyet Hoa Stuart E Bunn & Vanessa M Fry 《Aquaculture Research》2004,35(2):194-203
Stable isotope analysis was used to determine the sources of dietary nitrogen (N) and carbon (C) for shrimp during the rearing phase in extensive rice‐shrimp ponds in My Xuyen and Gia Rai districts, Vietnam. Farm‐made feed was added as a food source in shrimp ponds in My Xuyen district, and based on stable isotope analyses, was generally a poor dietary source. The commercial formulated feed used in Gia Rai also appeared to contribute little directly to the nutritional needs of the shrimp. In contrast, the natural biota in all ponds appeared to contribute substantially. In particular, biota from beam trawls and benthic organic matter were the most likely sources of nutrition in My Xuyen ponds, while benthic organic matter was the main source in Gia Rai ponds. δ15N ratios in the natural biota in My Xuyen farms decreased over the growing season, suggesting increased N fixation in the case of the benthic organic matter reaching values as low as 1‰. This suggests N‐limitation in the ponds and that natural biota become increasingly dependent on N fixed by algae and/or other microorganisms. There is the potential to promote the growth of the plankton and hence, the other natural biota, by the judicious addition of fertilizer. 相似文献
3.
4.
Differentiation between dogs with thrombosis and normal dogs using the overall hemostasis potential assay 下载免费PDF全文
Anna L. Dengate BVSc BMedSc Marie‐Christine Morel‐Kopp PhD Julia A. Beatty PhD BVetMed BSc Vanessa Barrs BVSc MVetClinStud Jody A. Braddock BVSc MVetClinStud Richard K. Churcher BVSc Bethany J. Wilson BVSc PhD Christopher M. Ward BMedSc MBChB PhD 《Journal of Veterinary Emergency and Critical Care》2016,26(3):446-452
5.
Ticehurst K Zaki S Maddern K Lingard A Barrs V Malik R 《Journal of Feline Medicine and Surgery》2007,9(6):521-525
A 14-year-old neutered male domestic shorthaired cat was presented to the University Veterinary Centre Sydney for evaluation and treatment of dental disease. This cat developed an unusual bradyarrhythmia under anaesthesia. The possible causes and treatment of the dysrythmia are discussed. 相似文献
6.
An understanding of the effects of salinity and sodicity on soil carbon (C) stocks and fluxes is critical in environmental
management, as the areal extents of salinity and sodicity are predicted to increase. The effects of salinity and sodicity
on the soil microbial biomass (SMB) and soil respiration were assessed over 12weeks under controlled conditions by subjecting
disturbed soil samples from a vegetated soil profile to leaching with one of six salt solutions; a combination of low-salinity
(0.5dSm−1), mid-salinity (10dSm−1), or high-salinity (30dSm−1), with either low-sodicity (sodium adsorption ratio, SAR, 1), or high-sodicity (SAR 30) to give six treatments: control (low-salinity
low-sodicity); low-salinity high-sodicity; mid-salinity low-sodicity; mid-salinity high-sodicity; high-salinity low-sodicity;
and high-salinity high-sodicity. Soil respiration rate was highest (56–80mg CO2-C kg−1 soil) in the low-salinity treatments and lowest (1–5mg CO2-C kg−1 soil) in the mid-salinity treatments, while the SMB was highest in the high-salinity treatments (459–565mg kg−1 soil) and lowest in the low-salinity treatments (158–172mg kg−1 soil). This was attributed to increased substrate availability with high salt concentrations through either increased dispersion
of soil aggregates or dissolution or hydrolysis of soil organic matter, which may offset some of the stresses placed on the
microbial population from high salt concentrations. The apparent disparity in trends in respiration and the SMB may be due
to an induced shift in the microbial population, from one dominated by more active microorganisms to one dominated by less
active microorganisms. 相似文献
7.
Phytomedicines are becoming more popular all over the world. Denture stomatitis (DS) presents as an inflammatory reaction in denture-bearing patients, under maxillary prosthesis with Candida albicans being the principal etiological agent. Many different methods of treatment for DS have been observed. The effects of the main medicinal plants claimed to be useful as antifungal agents in the treatment of DS are reviewed. Herbal remedies that have shown potential promise are mentioned, although much research is still required. 相似文献
8.
A dentigerous cyst was diagnosed in the right rostral maxilla of a 6-month-old Siamese cat affecting the maxillary right canine tooth. The deciduous maxillary right canine tooth was extracted and the dentigerous cyst wall was curetted. The permanent tooth was not removed, however it was mobile following the surgical procedure. Examination 6-months following surgery indicated appropriate development of the tooth with no mobility or periodontal pocket formation. The maxillary right canine tooth had an abnormal shape but was functional with an acceptable appearance. 相似文献
9.
工能基因组学:T-DNA介导的基因诱捕和植物基因鉴定(英文) 总被引:2,自引:0,他引:2
拟南芥菜、水稻、蕃茄、土豆、玉米、小麦和大豆的全基因组测序为植物细胞和发育生 物学研究提供了许多有用的信息。基因组学的中心任务是利用这些信息去探索蛋白质的功能 和鉴定与发育有关的重要基因。尽管依赖于毁坏基因和产生可识别的突变表型的经典遗传学 方法仍然是极为成功的基因鉴定方法,借助于报告基因结构,随机插入植物基因组的T-DNA 介导的基因诱捕正发展成为植物细胞和发育生物学研究的极强有力的技术。本文描述了基因 诱捕、启动子诱捕和增强子诱捕在植物生物学中的应用,并且希望这些基因鉴定方法有助于 植物分子生物学家和生物技术工作者的研究。 相似文献
10.
Pastur Guillermo Martínez Peri Pablo Luis Fernández María Cecilia Staffieri Gabriela Lencinas Mará Vanessa 《Journal of Forest Research》2002,7(3):165-174
Human commercial activities must be compatible with sustainable management to achieve species conservation in the natural
environment. After harvesting, diversity and abundance of understory species differ substantially from the pre-harvest situation.
Have knowledge of the changes that logging produces in all components of the system allows us to develop management alternatives
with reduced impacts. The objective of this work was to evaluate changes in density, biomass and diversity of understory species
along a forest shelterwood cut system management cycle in aNothofagus pumilio forest. Six forest management situations (postharvesting stands and different phases of forest development) were sampled
in a pureN. pumilio forest of Tierra del Fuego (Argentina) of middle-high site class (fromclass I toIII). Species number, density and biomass were modified substantially after a shelterwood cut. These were being greatest after
cutting and falling substantially when the forest canopy closes during theinitial growth phase, returning to values similar to this virgin forest when themature phase was reached. The impact of the forest management on understory species diversity is analyzed and discussed. The silvicultural
practices applied toN. pumilio forest in Tierra del Fuego permit the introduction of alien flora to the system, and produce great changes during the forest
management cycle.
To Celina Matteri, Itatí Ferraro, and Rosa Kofalt for their aid in taxonomical identification. To Juan Manuel Cellini, Ricardo
Vukasovic and Gregorio Martínez Pastur for their participation in the field work; and to the sawmillLos Castores, Universidad Nacional de la Patagonia Austral, Centro Austral de Investigaciones Científicas and Instituto Nacional de Tecnología
Agropecuaria for the institutional and financial support. 相似文献