Amplification of vertically propagating SH waves by multiple layers of Gibson soils

Using the Haskell–Thomson transfer matrix approach, an analytical solution is obtained for SH wave amplification by multiple layers of Gibson soils (i.e. viscoelastic layers with linearly varying shear moduli). Amplification spectra for typical soil and basement rock properties are calculated. A comparison of the Gibson soil response with that obtained for homogeneous soil models shows generally stronger amplifications associated with the Gibson soil.     

The relationship between abundances of meiofauna and their suspected microbial food (diatoms and bacteria)

Samples were taken bi-weekly for one year at a sand site and a mud site in the North Inlet Estuary, Georgetown, South Carolina, for meiofauna, their suspected microbial food (bacteria and diatoms), and associated physical factors. Linear regression techniques were used to correlate food abundance and physical factors with the density of meiofaunal taxa. At both sites diatoms positively correlated with meiofauna taxa, but bacteria did not. Physical factors were not correlated with meiofaunal or microbial abundances at the sand site. Whereas, at the mud site meiofauna and diatom abundances were positively correlated with the depth of the redox layer and inversely correlated with temperature. Peaks of meiofaunal abundance did not follow peaks of food abundance. Analysis of copepods at the species level indicated that taxa response was due to the response of the dominant species. Even though some correlations existed, this study suggests that copepod species and meiofauna at the gross taxonomic level do not respond to changes in potential food abundance. Physical factors apparently influence both meiofauna and diatoms in the same fashion. However, bacterial abundance was not positively correlated with any of the factors studied.     

The color temperature of a sunspot penumbra

The new Multi-Diode Array and the recently modified Universal Birefringent Filter were used at the Vacuum Tower Telescope at the Sacramento Peak National Observatory to measure the continuum color temperature of a sunspot penumbra between 428.4 and 667.6 nm. The results show that the color temperatures within the penumbral structures closely follow a measure of the wavelength average of the brightness temperature. These observations suggest that, if the dark penumbral filaments overlie a normal quiet photosphere, they are opaque to the radiation from below.Operated by the Association of Universities for Research in Astronomy, Inc., under contract AST 78-17292 with the National Science Foundation.     

Error analyses of resonant orbits for geodesy

An error analysis of resonant orbits for geodesy indicates that attempts to use resonance to recover high order geopotential coefficients may be seriously hampered by errors in the geopotential. This effect, plus the very high correlations (up to .99) of the resonant coefficients with each other and the orbital period in single satellite solutions, makesindividual resonant orbits of limited value for geodesy. Multiple-satellite, single-plane solutions are only a slight improvement over the single satellite case. Accurate determination of high order coefficients from low altitude resonant satellites requires multiple orbit planes and small drift-periods to reduce correlations and effects of errors of non-resonant geopotential terms. Also, the effects of gravity model errors on low-altitude resonant satellites make the use of tracking arcs exceeding two to three weeks of doubtful validity. Because high-altitude resonant orbits are less affected by non-resonant terms in the geopotential, much longer tracking arcs can be used for them.     

TREND SURFACE ANALYSIS OF GLACIALLY BURIED PLEISTOCENE ORGANIC DEPOSITS IN CENTRAL MICHIGAN*

Trend surfaces were determined and compared for the bedrock surface, two characteristics of the present topography, and 42 water well log reports of glacially buried carbonaceous horizons within drift from an area in central Michigan. Data almost certainly indicate that the glacially buried Pleistocene organic deposits represent two or more pre-Woodfordian paleosurfaces. Trend surface analysis of buried organic horizons may be useful for recognizing paleosurfaces and separating drift sheets in other areas with limited subsurface data.     

Associations between elevated atmospheric temperature and human mortality: a critical review of the literature

The effects of the anomalously warm European summer of 2003 highlighted the importance of understanding the relationship between elevated atmospheric temperature and human mortality. This review is an extension of the brief evidence examining this relationship provided in the IPCC’s Assessment Reports. A comprehensive and critical review of the literature is presented, which highlights avenues for further research, and the respective merits and limitations of the methods used to analyse the relationships. In contrast to previous reviews that concentrate on the epidemiological evidence, this review acknowledges the inter-disciplinary nature of the topic and examines the evidence presented in epidemiological, environmental health, and climatological journals. As such, present temperature–mortality relationships are reviewed, followed by a discussion of how these are likely to change under climate change scenarios. The importance of uncertainty, and methods to include it in future work, are also considered.