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151.
Florida manatees (Trichechus manatus latirostris) inhabit coastal regions because they feed on the aquatic vegetation that grows in shallow waters, which are the same areas where human activities are greatest. Noise produced from anthropogenic and natural sources has the potential to affect these animals by eliciting responses ranging from mild behavioral changes to extreme aversion. Sound levels were calculated from recordings made throughout behavioral observation periods. An information theoretic approach was used to investigate the relationship between behavior patterns and sound level. Results indicated that elevated sound levels affect manatee activity and are a function of behavioral state. The proportion of time manatees spent feeding and milling changed in response to sound level. When ambient sound levels were highest, more time was spent in the directed, goal‐oriented behavior of feeding, whereas less time was spent engaged in undirected behavior such as milling. This work illustrates how shifts in activity of individual manatees may be useful parameters for identifying impacts of noise on manatees and might inform population level effects. 相似文献
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154.
R. Andersen M. Poulin D. Borcard R. Laiho J. Laine H. Vasander E.‐T. Tuittila 《植被学杂志》2011,22(5):878-890
Question: What are the relative influences of environment and space in structuring the plant composition in a peatland complex? Location: Lakkasuo, southern boreal zone, Finland. Method: We used principal coordinates of neighbour matrices (PCNM) to model spatial structures in the plant composition of a peatland complex comprising ombrotrophic and minerotrophic, open and forested areas. We used redundancy analyses (RDA) and variation partitioning to assess the relative influences of chemical variables (peat and water characteristics), physical variables (hydrology, soil properties, shade), as well as broad‐scale (>350 m) and medium‐scale (100–350 m) spatial structures on vegetation assemblages. Results: We identified five different significant spatial patterns circumscribing (1) the minerotrophic–ombrotrophic gradient; (2) dry ombrotrophic and wet minerotrophic areas; (3) open and shaded areas; (4) dry open/shaded and wet patches within the ombrotrophic areas; and (5) dry open patches and dry forested patches. With spatial structures and environmental variables, we were able to model 30% of the variability in plant composition in the peatland complex, 13% of which was attributable to spatial structures alone. Conclusions: We demonstrated that in the peatland complex, the spatial dependence processes were more important at the broadest scale, and found that patterns at a medium scale might reflect finer‐scale patterns that were not investigated here. Spatial autocorrelation in vegetation composition in the peatland complex appeared to be driven by Sphagnum species. Our results emphasize that spatial modelling should be routinely implemented in studies looking at species composition, since they significantly increase the explained proportion of variance. 相似文献
155.
Questions: How does plant diversity (species richness, species abundance and rate of change) evolve in early succession on bare peat? Does succession converge towards one equilibrium stage or end up in several stages? Is there a regular pattern in succession velocity? Location: A mire in the calcareous Jura Mountains of northwest Switzerland. Method: Twenty‐one 1‐m2 permanent plots on bare peat were used to monitor temporal stages over a 21‐year period (1988 to 2008) in a Swiss mire where a slide occurred in 1987. Species diversity and life forms were analysed based on Shannon's equitability index and cover. We used classification and metric ordination techniques to investigate patterns of successional rates and trends. The high temporal resolution of the survey allowed the pattern of succession velocity to be analysed. Results: Species richness increased continuously over the 21 years of succession. The highest cover throughout the study period was the life form sedge. Time trajectories of the 21 plots revealed three alternative pathways towards intermediate equilibrium stages in the first years, still not converging in the later stages. Changes in succession velocity reached a first maximum about 6 years after the slide had occurred and a second maximum 12 years later. 相似文献
156.
Tae-Joon Park Ji-Sun Kim Sung-Sub Choi Yongae Kim 《Biotechnology and Bioprocess Engineering》2011,16(3):477-481
The amyloid precursor protein (APP) is an integral transmembrane protein which has been suggested to play a central role in the pathogenesis of Alzheimer’s disease. Despite the enormous amount of research conducted on amyloid protein, the precise mechanism of its toxic effect is not yet fully understood. To better understand the mechanism and function of amyloid protein, it is critical to elucidate the three-dimensional structure of the single transmembrane spanning region of human APP (hAPP-TM). Unfortunately, it is difficult to prepare the peptide sample because hAPP-TM is a membrane-bound protein that transverses the lipid bilayer of the cell membrane. Generally, the preparation of a transmembrane peptide is very difficult and time-consuming. In fact, high yield production of transmembrane peptides has been limited by experimental difficulties related to insufficient yields and the low solubility of such peptides. In this study, we describe experimental processes developed to optimize the expression, purification, and NMR measurement conditions for hAPP-TM transmembrane peptide. 相似文献
157.
Myung-Pyo Jung Hea-Son Bang Myung-Hyun Kim Kee-Kyung Kang Deog-Bae Lee 《Journal of Asia》2011,14(3):289-292
This study was conducted to monitor the abundance and distribution of the ussur brown katydid, Paratlanticus ussuriensis in South Korea, and to gather basic information about potential outbreak areas of this species. P. ussuriensis samples were collected from April to July in 2009 and 2010 using the transect method at the city or gun level. P. ussuriensis were identified in 86 cities or guns, and eight guns were determined to be potential risk areas of P. ussuriensis outbreaks. The current distribution of P. ussuriensis is well matched with the distribution of broadleaf trees. Their distribution and population density are expected to increase due to the expanding distribution of Quercus spp., the major food source of P. ussuriensis. 相似文献
158.
The genus Cryptaphis Hille Ris Lambers 1947 is described for the first time in Korea with new records of two species, Cryptaphis geranicola (Shinji 1935) and Cryptaphis menthae Takahashi 1961. Cryptaphis geranicola was collected from Geranium thunbergii (Lamiaceae) and C. menthae was collected from Isodon inflexus (Lamiaceae). Important characteristics are re-described, illustrated, and measured in apterous and alate viviparous females. 相似文献
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