835 resultados para Plato - Criticism and interpretation
Resumo:
Monitoring of Phaeocystis since 1948 during the Continuous Plankton Recorder survey indicates that over the last 5.5 decades the distribution of its colonies in the North Atlantic Ocean was not restricted to neritic waters: occurrence was also recorded in the open Atlantic regions sampled, most frequently in the spring. Apparently, environmental conditions in open ocean waters, also those far oVshore, are suitable for complete lifecycle development of colonies (the only stage recorded in the survey). In the North Sea the frequency of occurrence was also highest in spring. Its southeastern part was the Phaeocystis abundance hotspot of the whole area covered by the survey. Frequency was especially high before the 1960s and after the 1980s, i.e., in the periods when anthropogenic nutrient enrichment was relatively low. Changes in eutrophication have obviously not been a major cause of long-term Phaeocystis variation in the southeastern North Sea, where total phytoplankton biomass was related signiWcantly to river discharge. Evidence is presented for the suggestion that Phaeocystis abundance in the southern North Sea is to a large extent determined by the amount of Atlantic Ocean water Xushed in through the Dover Strait. Since Phaeocystis plays a key role in element Xuxes relevant to climate the results presented here have implications for biogeochemical models of cycling of carbon and sulphur. Sea-to-air exchange of CO2 and dimethyl sulphide (DMS) has been calculated on the basis of measurements during single-year cruises. The considerable annual variation in phytoplankton and in its Phaeocystis component reported here does not warrant extrapolation of such figures.
Resumo:
The contribution of electron-phonon scattering and grain boundary scattering to the mid-IR (lambda = 3.392 mum) properties of An has been assessed by examining both bulk, single crystal samples-Au(1 1 1) and Au(1 1 0)-and thin film, polycrystalline An samples at 300 K and 100 K by means of surface plasmon polariton excitation. The investigation constitutes a stringent test for the in-vacuo Otto-configuration prism coupler used to perform the measurements, illustrating its strengths and limitations. Analysis of the optical response is guided by a physically based interpretation of the Drude model. Relative to the reference case of single crystal Au at 100 K (epsilon = - 568 + i17.5), raising the temperature to 300 K causes increased electron-phonon scattering that accounts for a reduction of similar to40 nm in the electron mean free path. Comparison of a polycrystalline sample to the reference case determines a mean free path due to grain boundary scattering of similar to 17 nm, corresponding to about half the mean grain size as determined from atomic force microscopy and indicating a high reflectance coefficient for the An grain boundaries. An analysis combining consideration of grain boundary scattering and the inclusion of a small percentage of voids in the polycrystalline film by means of an effective medium model indicates a value for the grain boundary reflection coefficient in the range 0.55-0.71. (C) 2005 Elsevier B.V. All rights reserved.
Resumo:
This article is a response to an article by Ray Mackay (1996) which constitutes an attack on stylistic analysis in general, and the writings of the above authors and Ron Carter in particular. Mackay's article (in Language and Communication) accuses stylistics of 'scientificness' and claims that its attempt to provide objective analyses of literary texts is futile.1 We suggest that Mackay has misrepresented what stylisticians have said about objectivity, and that his understanding of objectivity, science and the nature of text-interpretative argument is seriously flawed.
Resumo:
Scanning tunnelling microscope (STM) tip-induced light emission from Au and Ag has been studied. Thin film samples similar to100nm thick were prepared by thermal evaporation at 0.5nm/s onto a room-temperature glass substrate to produce grains of 20-50nm in lateral dimension at the surface. Light emission from the samples in the STM was quasi-simultaneously recorded with the topography, at 1.8V tip bias and 3-40nA current, alternating pixel by pixel at the same bias. Typically, a surface scan range of 150 nm x 150 nm was surveyed. Au, W and PtIr tips were used.
Resumo:
While the incorporation of mathematical and engineering methods has greatly advanced in other areas of the life sciences, they have been under-utilized in the field of animal welfare. Exceptions are beginning to emerge and share a common motivation to quantify 'hidden' aspects in the structure of the behaviour of an individual, or group of animals. Such analyses have the potential to quantify behavioural markers of pain and stress and quantify abnormal behaviour objectively. This review seeks to explore the scope of such analytical methods as behavioural indicators of welfare. We outline four classes of analyses that can be used to quantify aspects of behavioural organization. The underlying principles, possible applications and limitations are described for: fractal analysis, temporal methods, social network analysis, and agent-based modelling and simulation. We hope to encourage further application of analyses of behavioural organization by highlighting potential applications in the assessment of animal welfare, and increasing awareness of the scope for the development of new mathematical methods in this area.