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11.
This paper examines key factors used in protecting the migratory North Atlantic right whale within the context of a marine protected area (MPA) system, using the Grand Manan Whale Conservation Area, in New Brunswick Canada, as a case study example. Designated as a conservation area in 1993, before the Oceans Act came into effect, the Grand Manan conservation area currently does not form part of the Canadian network of MPAs. Given the possibility that MPA designation may occur, the paper examines factors that should be considered in meeting International Union for Conservation of Nature (IUCN) MPA design criteria and IUCN evaluation model requirements. An MPA evaluation framework based on an IUCN evaluation model (Hockings et al., 2000 [1]) is designed to assess the effectiveness of an MPA in protecting a migratory right whale. Case study results indicate that current management and research activities for the Grand Manan conservation area address most governance, biophysical and socio-economic issues under an IUCN evaluation framework. On a site basis, it is recommended that the Grand Manan conservation area be designated as a component of the Canadian network of MPAs and that regulations be developed and implemented under the Species at Risk Act to clearly define activities considered damaging or destructive to right whale critical habitat. Recommendations also suggest the preparation of a combined site management-action plan for the Grand Manan conservation area indicating how activities specified in North Atlantic Right Whale Recovery Strategy will be implemented locally. On a regional and international basis, recommendations call for an internationally coordinated and integrated approach to right whale protection within the context of a network of designated critical habitat areas. Recommended activities include: continued Canadian participation in cross-border research and actions to mitigate threats to the right whales over their migratory range; development of a regional right whale management and monitoring strategy; and designation of additional critical habitats in national/international waters. It is further recommended that the evaluation framework developed by this paper be used as a model in assessing the conservation and management effectiveness of MPAs protecting other migratory marine species.  相似文献   
12.
Cepheid parallaxes and the Hubble constant   总被引:1,自引:0,他引:1  
Revised Hipparcos parallaxes for classical Cepheids are analysed together with 10 Hubble Space Telescope ( HST )-based parallaxes. In a reddening-free V , I relation we find that the coefficient of log  P is the same within the uncertainties in our Galaxy as in the Large Magellanic Cloud (LMC), contrary to some previous suggestions. Cepheids in the inner region of NGC 4258 with near solar metallicities confirm this result. We obtain a zero-point for the reddening-free relation and apply it to the Cepheids in galaxies used by Sandage et al. to calibrate the absolute magnitudes of Type Ia supernova (SNIa) and to derive the Hubble constant. We revise their result for H 0 from 62 to 70 ± 5 km s−1 Mpc−1. The Freedman et al. value is revised from 72 to 76 ± 8 km s−1 Mpc−1. These results are insensitive to Cepheid metallicity corrections. The Cepheids in the inner region of NGC 4258 yield a modulus of 29.22 ± 0.03 (int.) compared with a maser-based modulus of 29.29 ± 0.15. Distance moduli for the LMC, uncorrected for any metallicity effects, are 18.52 ± 0.03 from a reddening-free relation in V , I ; 18.47 ± 0.03 from a period–luminosity relation at K ; 18.45 ± 0.04 from a period–luminosity–colour relation in J , K . Adopting a metallicity correction in V , I from Macri et al. leads to a true LMC modulus of 18.39 ± 0.05.  相似文献   
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Published data for large-amplitude asymptotic giant branch variables in the Large Magellanic Cloud (LMC) are re-analysed to establish the constants for an infrared ( K ) period–luminosity relation of the form   M K =ρ[log  P − 2.38]+δ  . A slope of  ρ=−3.51 ± 0.20  and a zero-point of  δ=−7.15 ± 0.06  are found for oxygen-rich Miras (if a distance modulus of 18.39 ± 0.05 is used for the LMC). Assuming this slope is applicable to Galactic Miras we discuss the zero-point for these stars using the revised Hipparcos parallaxes together with published very long baseline interferometry (VLBI) parallaxes for OH masers and Miras in globular clusters. These result in a mean zero-point of  δ=−7.25 ± 0.07  for O-rich Galactic Miras. The zero-point for Miras in the Galactic bulge is not significantly different from this value.
Carbon-rich stars are also discussed and provide results that are consistent with the above numbers, but with higher uncertainties. Within the uncertainties there is no evidence for a significant difference between the period–luminosity relation zero-points for systems with different metallicity.  相似文献   
15.
We report laboratory experiments and modeling calculations investigating the effect of a hydrocarbon coating on ammonia ice spectral signatures. Observational evidence and thermochemical models indicate an abundance of ammonia ice clouds in Jupiter's atmosphere. However, spectrally identifiable ammonia ice clouds are found covering less than 1% of Jupiter's atmosphere, notably in areas of strong vertical transport, indicating a short lifetime for the signature of ammonia absorption on condensed ammonia particles [Baines, K.H., Carlson, R.W., Kamp, L.W., 2002. Icarus 159, 74-94]. Current literature has suggested coating of ammonia ice particles by a hydrocarbon haze as a possible explanation for this paradox. The work presented here supports the inference of a coating effect that can alter or suppress ammonia absorption features. In the experiments, thin films of ammonia ices are deposited in a cryogenic apparatus, coated with hydrocarbons, and characterized by reflection-absorption infrared spectroscopy. We have observed the effects on the ammonia ice absorption features near 3 and 9 μm with coverage by thin layers of hydrocarbons. Modeling calculations of these multilayer thin films assist in the interpretation of the experimental results and reveal the important role of optical interference in altering the aforementioned ammonia spectral features. Mie and T-matrix scattering calculations demonstrate analogous effects for ammonia ice particles and investigate the relative effects of ammonia ice particle size, shape, and coating layer thickness on the ice particle spectral signatures.  相似文献   
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17.
The west watershed of Mirror Lake in the White Mountains of New Hampshire contains several terraces that are at different altitudes and have different geologic compositions. The lowest terrace (FSE) has 5 m of sand overlying 9 m of till. The two next successively higher terraces (FS2 and FS1) consist entirely of sand and have maximum thicknesses of about 7 m. A fourth, and highest, terrace (FS3) lies in the north‐west watershed directly adjacent to the west watershed. This highest terrace has 2 m of sand overlying 8 m of till. All terraces overlie fractured crystalline bedrock. Numerical models of hypothetical settings simulating ground‐water flow in a mountainside indicated that the presence of a terrace can cause local ground‐water flow cells to develop, and that the flow patterns differ based on the geologic composition of the terrace. For example, more ground water moves from the bedrock to the glacial deposits beneath terraces consisting completely of sand than beneath terraces that have sand underlain by till. Field data from Mirror Lake watersheds corroborate the numerical experiments. The geology of the terraces also affects how the stream draining the west watershed interacts with ground water. The stream turns part way down the mountainside and passes between the two sand terraces, essentially transecting the movement of ground water down the valley side. Transects of water‐table wells were installed across the stream's riparian zone above, between, and below the sand terraces. Head data from these wells indicated that the stream gains ground water on both sides above and below the sand terraces. However, where it flows between the sand terraces the stream gains ground water on its uphill side and loses water on its downhill side. Biogeochemical processes in the riparian zone of the flow‐through reach have resulted in anoxic ground water beneath the lower sand terrace. Results of this study indicate that it is useful to understand patterns of ground‐water flow in order to fully understand the flow and chemical characteristics of both ground water and surface water in mountainous terrain. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
18.
Geographic information systems (GIS) have become essential tools in the public health domain, especially when it comes to monitoring and surveillance of disease. The purpose of this article is to describe and explore the benefits of using GIS to improve public health emergency response during a global pandemic and, in particular, how to effectively optimize the allocation of public health resources in a rural setting using a data-driven approach that considers the multifactorial demand for new COVID-19 testing sites. Herein, the authors present their interprofessional project as an example of such efforts to inform applications for practice. The team developed a GIS-based multicriteria decision analysis model for use by decision-makers and public health experts in similar future planning and response scenarios. Focus is placed on rural characteristics (e.g., accessibility), vulnerable populations, and daily changing conditions (e.g., COVID-19 daily case fluctuations) that create additional challenges for public health agencies and policymakers.  相似文献   
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20.
Sediments from Rapid Lake document glacial and vegetation history in the Temple Lake valley of the Wind River Range, Wyoming over the past 11,000 to 12,000 yr. Radiocarbon age determinations on basal detrital organic matter from Rapid Lake (11,770 ± 710 yr B.P.) and Temple Lake (11,400 ± 630 yr B.P.) bracket the age of the Temple Lake moraine, suggesting that the moraine formed in the late Pleistocene. This terminal Pleistocene readvance may be represented at lower elevations by the expansion of forest into intermontane basins 12,000 to 10,000 yr B.P. Vegetation in the Wind River Range responded to changing environmental conditions at the end of the Pleistocene. Following deglaciation, alpine tundra in the Temple Lake valley was replaced by a Pinus albicaulis parkland by about 11,300 14C yr B.P. Picea and Abies, established by 10,600 14C yr B.P., grew with Pinus albicaulis in a mixed conifer forest at and up to 100 m above Rapid Lake for most of the Holocene. Middle Holocene summer temperatures were about 1.5°C warmer than today. By about 5400 14C yr B.P. Pinus albicaulis and Abies became less prominent at upper treeline because of decreased winter snowpack and higher maximum summer temperatures. The position of the modern treeline was established by 3000 14 C yr B.P. when Picea retreated downslope in response to Neoglacial cooling.  相似文献   
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