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Moriarty-Schieven GH Powers JA Butner HM Wannier PG Keene J 《The Astrophysical journal》2000,533(2):L143-L145
L1551NE is a very young (class 0 or I) low-mass protostar located close to the well-studied L1551 IRS 5. Here we present evidence, from 1.3 mm continuum interferometric observations at approximately 1&arcsec; resolution, for a binary companion to L1551NE. The companion, whose 1.3 mm flux density is approximately 13 that of the primary component, is located 1&farcs;43 ( approximately 230 AU at 160 pc) to the southeast. The millimeter-wave emission from the primary component may have been just barely resolved, with a deconvolved size of approximately 0&farcm;82x0&farcm;70 ( approximately 131x112 AU). The companion emission was unresolved (<100 AU). The pair is embedded within a flattened circumbinary envelope of size approximately 5&farcm;4x2&farcm;3 ( approximately 860x370 AU). The masses of the three components (i.e., from the circumstellar material of the primary star and its companion and the envelope) are approximately 0.044, 0.014, and 0.023 M middle dot in circle, respectively. 相似文献
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Santos RG Martins AS Farias Jda N Horta PA Pinheiro HT Torezani E Baptistotte C Seminoff JA Balazs GH Work TM 《Marine pollution bulletin》2011,62(6):1297-1302
To show the influence of coastal habitat degradation on the availability of food for green turtles (Chelonia mydas), we assessed the dietary preferences and macroalgae community at a feeding area in a highly urbanized region. The area showed low species richness and was classified as degraded. We examined stomach contents of 15 dead stranded turtles (CCL = 44.0 cm (SD 6.7 cm)). The diet was composed primarily of green algae Ulva spp. (83.6%). In contrast, the macroalgae community was dominated by the green alga Caulerpa mexicana. We found a selection for red algae, seagrass and Ulva spp., and avoidance for C. mexicana and brown alga Dictyopteris delicatula. The low diversity of available food items, possibly a result of environmental degradation, likely contributed to the low dietary diversity. The nutritional implications of this restricted diet are unclear. 相似文献
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An integrated fuzzy simulation-assessment method (FSAM) was developed for assessing environmental risks from petroleum hydrocarbon contamination in ground water. In the FSAM, techniques of fuzzy simulation and fuzzy risk assessment were coupled into a general framework to reflect a variety of system uncertainties. A petroleum-contaminated site located in western Canada was selected as a study case for demonstrating applicability of the proposed method. The risk assessment results demonstrated that system uncertainties would significantly impact expressions of risk-level outputs. A relatively deterministic expression of the risks would have clearer representations of the study problem but may miss valuable uncertain information; conversely, an assessment under vaguer system conditions would help reveal potential consequences of adverse effects but would suffer from a higher degree of fuzziness in presenting the modeling outputs. Based on the risk assessment results, a decision analysis procedure was used to calculate a general risk index (GRI) to help identify proper responsive actions. The proposed method was useful for evaluating risks within a system containing multiple factors with complicated uncertainties and interactions and providing support for identifying proper site management strategies. 相似文献
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