Gaussian beam scattering by a spheroidal particle is studied in detail. A theoretical procedure is given to expand an incident Gaussian beam in terms of spheroidal vector wave functions within the generalized Lorenz-Mie theory framework. Exact analytic solutions are obtained for an arbitrarily oriented spheroid with nonconfocal dielectric coating. Normalized differential scattering cross sectio...

The pollen morphology of Pelargonium endlicherianum Fenzl. and Pelargonium quercetorum Agnew. from the family Geraniaceae was examined under light microscopy and scanning electron microscopy. Pollen morphologies are eurypalynous. The pollen grains were tricolporate, prolate-spheroidal and large. Aperture was ectoaperture, colpus was short, and the pores were oblate-spheroidal and large. The exi...

Estimation of the temperature dependence of natural feldspar weathering in two catchments at different elevations yields an apparent Arrhenius activation energy of 18.4 kcal/mol (77.0 kj/mol), much higher than most laboratory values. This finding supports recent suggestions that hydrolytic weathering of silicate minerals may consume carbonic acid and thereby remove atmospheric carbon dioxide mo...

The effect of watershed spatial scale on chemical weathering is inadequately known for subtropical environments. In order to determine the relationship between watershed scale and weathering chemistry, the Enoree River basin was sampled at seven different spatial scales ranging from second-order watersheds smaller than 2 km^2 to a sixth order watershed of 1840 km^2. The second-order watersheds ...

The weathering hypothesis suggests that early childbearing is an adaptive mechanism for disadvantaged young women, especially African Americans, who believe that their health status may decline as they move through adulthood. Implicitly, weathering assumes that these young women use contextual clues to formulate the likelihood of their own future adult health. We propose a simple yet, to date, ...

The composition of igneous rocks in the continental crust has changed throughout Earth's history. However, the impact of these compositional variations on chemical weathering, and by extension on seawater and atmosphere evolution, is largely unknown. We use the strontium isotope ratio in seawater [(87Sr/86Sr)seawater] as a proxy for chemical weathering, and we test the sensitivity of (87Sr/86Sr...

Several operative limitations are involved in the quantitative evaluation of damage processes. To plan an intervention, the assessment of the state of conservation appears incomplete without a realistic estimation. Stone and brick and above all sculptured surfaces and paintings need characterization, quantification, interpretation and rating of the weathering. In this field the use of non destr...

The long-term carbon cycle is vital for maintaining liquid water oceans on rocky planets due to the negative climate feedbacks involved in silicate weathering. Plate tectonics plays a crucial role in driving the long-term carbon cycle because it is responsible for CO2 degassing at ridges and arcs, the return of CO2 to the mantle through subduction, and supplying fresh, weatherable rock to the s...