Lowering of the complexity of quantum chemistry methods by choice of representation

The complexity of the standard hierarchy of quantum chemistry methods is not invariant to the choice of representation. This work explores how the scaling of common quantum chemistry methods can be reduced using real-space, momentum-space, and time-dependent intermediate representations without introducing approximations. We find the scalings of exact Gaussian basis Hartree--Fock theory, second-order M{\o}ller-Plesset perturbation theory, and coupled cluster theory (specifically, linearized coupled cluster doubles and the distinguishable cluster approximation with doubles) to be $\mathcal{O}(N^3)$, $\mathcal{O}(N^3)$, and $\mathcal{O}(N^5)$ respectively, where $N$ denotes system size. These scalings are not asymptotic and hold over all ranges of $N$

Gaussian and plane-wave mixed density fitting for periodic systems

We introduce a mixed density fitting scheme that uses both a Gaussian and a plane-wave fitting basis to accurately evaluate electron repulsion integrals in crystalline systems. We use this scheme to enable efficient all-electron Gaussian based periodic density functional and Hartree-Fock calculations

A recursively formulated first-order semianalytic artificial satellite theory based on the generalized method of averaging. Volume 2: The explicit development of the first-order averaged equations of motion and for the nonspherical gravitational and nonresonant third-body perturbations

For abstract, see N78-28147

Auscultation and Oscillometry Result in Different Blood Pressure Readings When Using Visual Display on an iOS Operated Device

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Microclimate and activity of the lizard Angolosaurus skoogi on a dune slipface

The lizard Angolosaurus skoogi inhabits the surface and subsurface environments of sand dunes of the northern Namib Desert. We have related posture, locomotion, and other aspects of surface activity to the microclimate prevailing above and below the surface. Globe temperature was the best microclimatic correlate of surface activity. From our analysis, we concluded that surface thermoregulatory behaviour of A. skoogi is facultative, and aimed at maintaining a body temperature compatible with foraging and other obligatory surface activities

Ocean Chlorophyll Studies from a U-2 Aircraft Platform

Chlorophyll gradient maps of large ocean areas were generated from U-2 ocean color scanner data obtained over test sites in the Pacific and Atlantic Oceans. The delineation of oceanic features using the upward radiant intensity relies on an analysis method which presupposes that radiation backscattered from the atmosphere and ocean surface can be properly modeled using a measurement made at 778 nm. An estimation of the chlorophyll concentration was performed by properly ratioing radiances measured at 472 nm and 548 nm after removing the atmospheric effects. The correlation between the remotely sensed data and in-situ surface chlorophyll measurements was validated in two sets of data. The results show that the correlation between the in-situ measured chlorophyll and the derived quantity is a negative exponential function and the correlation coefficient was calculated to be -0.965

Laser-modified one- and two-photon absorption:Expanding the scope of optical nonlinearity

It is shown that conventional one-photon and two-photon absorption processes can be made subject to nonlinear optical control, in each case significantly modifying the efficiency of absorption, through the effect of a secondary, off-resonant stimulus laser beam. The mechanistic origin of these laser-modified absorption processes, in which the stimulus beam emerges unchanged, is traced to higher-order terms in standard perturbation treatments. These normally insignificant terms become unusually prominent when the secondary optical stimulus is moderately intense. Employing a quantum formulation, the effects of the stimulus beam on one-photon and two-photon absorption are analyzed, and calculations are performed to determine the degree of absorption enhancement, and the form of spectral manifestation, under various laser intensities. The implications of differences in selection rules are also considered and exemplified, leading to the identification of dark states that can be populated as a result of laser-modified absorption. Attention is also drawn to the possibility of quantum nondemolition measurements, based on such a form of optical nonlinearity

Paper Session I-C - Seeds II: More Tomatoes from Space

NASA Life Sciences Outreach, in collaboration with several other organizations, is getting ready to release space exposed seeds to teachers and students. This project, called Space Exposed Experiment Developed for Students II (SEEDS II) was designed to provide teachers and students with seeds and information so that they can conduct biological research relating to the effects of the space and undersea environments