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61.
A. P. Jacob T. R. Bedding J. G. Robertson M. Scholz 《Monthly notices of the Royal Astronomical Society》2000,312(4):733-746
We discuss the wavelength dependence of angular diameters of M giants from an observational perspective. Observers cannot directly measure an optical-depth radius for a star, despite this being a common theoretical definition. Instead, they can use an interferometer to measure the square of the fringe visibility. We present new plots of the wavelength-dependent centre-to-limb variation (CLV) of intensity of the stellar disc as well as visibility for Mira and non-Mira M giant models. We use the terms 'CLV spectra' and 'visibility spectra' for these plots. We discuss a model-predicted extreme limb-darkening effect (also called the narrow-bright-core effect) in very strong TiO bands which can lead to a misinterpretation of the size of a star in these bands. We find no evidence as yet that this effect occurs in real stars. Our CLV spectra can explain the similarity in visibilities of R Dor (M8IIIe) that have been observed recently, despite the use of two different passbands. We compare several observations with models, and find that the models generally underestimate the observed variation in visibility with wavelength. We present CLV and visibility spectra for a model that is applicable to the M supergiant α Ori. 相似文献
62.
W. E. Carter D. S. Robertson T. E. Pyle J. Diamante 《Geophysical Journal International》1986,87(1):3-13
Summary. Under project IRIS (International Radio Interferometric Surveying) geodesists are using Very Long Baseline Interferometry (VLBI) to monitor polar motion to 1-2 ms of arc and UT1 to 0.05-0.10 ms, and to develop a global geodynamic network to detect and study centimetre level displacements of reference points associated with large-scale phenomena such as tectonic plate motion and glacial rebound. Differential positioning techniques using the signals broadcast by the satellites of the Global Positioning System (GPS) are being used to study finer scale phenomena, such as localized subsidence, and economically to relate these specialized surveys to the geodynamic network. Including tide gauge stations in this system will make it possible to detect motions of specific gauges and correct or delete the measurements from those gauges when computing changes in sea-level. The National Oceanic and Atmospheric Administration (NOAA) has selected several tide gauges on the east and west coasts of the United States, and initial epoch GPS surveys to tie the gauges to VLBI observations have already begun. Other countries participating in project IRIS are planning similar activities. In addition to providing a globally based land reference datum for the tide gauge measurements, the IRIS polar motion and UT1 time series may contribute directly to monitoring and interpreting global sea level changes. Changes in the volume and distribution of ice masses result in long-term motions of the axis of rotation, and sea-level changes affect the length of day (lod). The IRIS time series will certainly have the resolution required to detect the expected polar motion and changes in lod, and a properly designed global VLBI/GPS network should allow the ice/sea-level effects to be separated from crustal dynamics effects. 相似文献
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While political ideology is a consistent predictor of public environmental views in the United States, religious affiliation may also be an important correlate of environmental attitudes, especially in regions with a majority denomination. Using data from a 2014 survey in five communities across Utah, Idaho, and Wyoming (n = 906) experiencing renewable energy development, we investigate the influence of religious affiliation on environmental beliefs, views about climate change, and support for renewable energy. We are particularly interested in the influence of Mormonism, an understudied area of research. We find Mormonism, Protestantism, and Catholicism all significantly and negatively related to general pro-environment beliefs. However, this relationship doesn’t hold as consistently for views about global warming or renewable energy development. We also find income, gender, length of residence, and political orientation to be important predictors of environmental attitudes, and that general environmental beliefs are only weakly related to views about renewable energy. 相似文献
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A. H. F. Robertson O. Parlak N. Yıldırım P. Dumitrica K. Taslı 《International Journal of Earth Sciences》2016,105(1):167-201
Evidence of rifting and continental break-up to form the S Neotethys is found within the volcanic-sedimentary Koçali Complex. This is a folded, thrust-imbricated succession that includes lavas, volcaniclastic sediments, pelagic carbonates, radiolarites and manganiferous deposits. Interbedded ribbon cherts contain radiolarians of Late Triassic to Late Jurassic age. The lower part of the succession of Mid?-Late Triassic age (Tarasa Formation) is dominated by enriched mid-ocean ridge basalt (E-MORB). The overlying Late Triassic to Mid-Jurassic interval (Konak Formation) is characterised by intercalations of ocean island basalt and E-MORB. Taking account of structural position, the basalts erupted within the outer part of a continent–ocean transition zone. Continental break-up probably occurred during the Late Triassic (Carnian–Norian). Early to Mid-Jurassic lavas and volcaniclastic sediments record volcanism probably after continental break-up. In addition, the Karadut Complex is a broken formation that is located at a relatively low structural position just above the Arabian foreland. Pelagic carbonates, redeposited carbonates and radiolarites predominate. Radiolarians are dated as Early to Mid-Jurassic and Late Cretaceous in age. The pelagic carbonates include planktic foraminifera of Late Cretaceous age. The Karadut Complex resulted from the accumulation of calcareous gravity flows, pelagic carbonate and radiolarites in a relatively proximal, base-of-slope setting. After continental break-up, MORB and ophiolitic rocks formed within the S Neotethys further north. Tectonic emplacement onto the Arabian platform took place by earliest Maastrichtian time. Regional interpretation is facilitated by comparisons with examples of Triassic rifting and continental break-up in the eastern Mediterranean region and elsewhere. 相似文献
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68.
Based on quarterly sampling (n = 260) over four years (1985–1989) from California's San Pedro Shelf, the Pearson-Rosenberg Model (PRM) or organic enrichment was tested for the Orange County ocean outfall. The null hypothesis was that test species, abundance, and biomass curves (SAB) from the shelf closely resemble those from the model. Principal areas of agreement between test curves and model curves include increased abundance and biomass approaching an ocean outfall. Major departures from the PRM include: (1) no sharp decline in SAB curves to azoic conditions, (2) displacement of SAB curves away from the outfall, and (3) opportunistic species did not exclude or eliminate rare species. Moreover, the role of local dominant species (bivalve—Parvilucina tenuisculpta, ostracod—Euphilomedes carcharodonta polychaetous annelid—Capitella capitata) can greatly influence SAB curves within the model. Bioenhancement should not necessarily be viewed as a diagnostic feature of a polluted site. Since the PRM was originally developed for semi-enclosed, low energy depositional habitats with long residence times (fjords, sea lochs), open ocean, high energy, erosional habitats (coast and shelf) may not be the most appropriate sites to apply this model. Uncritical application of the PRM to the Orange County ocean outfall may lead to unnecessary and costly decisions. 相似文献
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The past 50 years in the Gulf of Maine and Georges Bank is marked by a growing divide between fishermen, scientists, and managers. This paper tracks the scientific, regulatory, social and political evolution of fisheries management in the Northwest Atlantic, culminating in a distrustful and adversarial climate, a convergence of diverse policy needs, and the emergence of a multi-stakeholder cooperative research program—the Northeast Consortium. The institutional structure and activities of the Northeast Consortium are presented and we conclude with a discussion of the role of cooperative research in building mutual understanding and respect, trust and scientific legitimacy. 相似文献