Determining Modes for Continuous Data Assimilation in 2D Turbulence

We study the number of determining modes necessary for continuous data assimilation in the two-dimensional incompressible Navier–Stokes equations. Our focus is on how the spatial structure of the body forcing affects the rate of continuous data assimilation and the number of determining modes. We treat this problem analytically by proving a convergence result depending on the H ^–1 norm of f and computationally by considering a family of forcing functions with identical Grashof numbers that are supported on different annuli in Fourier space. The rate of continuous data assimilation and the number of determining modes is shown to depend strongly on the length scales present in the forcing.     

Total surface areas of Group IVA organometallic compounds: Predictors of toxicity to algae and bacteria

There is a high correlation between molecular surface area (TSA) of triorganotin and triorganolead compounds and their toxicity towards a bacterium (Escherichia coli) and an alga (Selenastrum capricornutum). Parallel attempts to correlate other Group IVA organometals incorporating silicon or germanium were unsuccessful. It was further demonstrated, however, that a high correlation was obtainable between certain series of compounds with the same organic substituent but different metal centers involving all Group IVA elements. In both instances, the inability to obtain a quantitative structure-activity relationship (QSAR) for all systems studied appears to be a function of the solubility of the compounds. While organotin TSA values have been found to correlate well with their toxicities toward various organisms, this study clearly suggests that this type of QSAR can be readily extended to include other organometal systems, provided that there is no solubility problem and the toxicity is a function of the hydrophobicity of the organometal compounds.     

Unified Interactive Multiple Objective Programming: An Open Architecture For Accommodating New Procedures

It has previously been shown that nine of the most prominent procedures of interactive multiple objective programming can be considered as special cases of a common procedure called the unified algorithm. In this paper, we show how four additional procedures can be similarly included in the unified approach. Also, the paper presents a procedure-switching matrix that depicts the possibilities for switching from one procedure to another, one iteration to the next, in the unified algorithm if so directed by a user.     

SENSITIZATION OF PHOTOREACTIONS IN EIMHJELLEN'S RHODOPSEUDOMONAS BY A PIGMENT ABSORBING AT 830 mμ*

Abstract— The excitation spectrum for bacteriochlorophyll b fluorescence, the action spectrum for cytochrome-553 oxidation, and the action spectrum for P-985 bleaching are compared to the absorption (1-T) spectrum of a Rhodopseudomonas sp. NHTC 133 extract over the range 770 to 930 mμ. These spectra show that a minor pigment P-830 is more effective in sensitizing cytochrome oxidation and P-985 bleaching than in exciting fluorescence of Bchl b. These results are consistent with the proposal that P-830 is a form of Bchl b in special relation to the reaction center pigment P-985.     

DISCREPANCIES IN THE MEASUREMENT OF SPECTRAL SOURCES

Abstract— Comparison of spectroradiometric and meter measurements of a series of ultraviolet radiation sources indicates that a wide divergence between readings can occur. We found that with a xenon are filtered as a solar simulator producing UV-A (320–400 nm) and UV-B (290–320 nm) radiation, the meter can either over-or underestimate the emission of the source when different cutoff filters are used. The most severe discrepancy appears with the UV-B meter reading, although the UV-A reading can also be problematic. Meters should be calibrated against the specific sources they will be used to measure.     

BIOCHEMICAL FACTORS AFFECTING THE QUANTUM EFFICIENCY OF HYDROGEN PRODUCTION BY MEMBRANES OF GREEN PHOTOSYNTHETIC BACTERIA*

Abstract— Photohydrogen production, 200-700 μmol H₂ h^?1 (mg bacteriochlorophyll a)^?1 has been obtained in a system containing unit membrane vesicles (Complex I) from the green photosynthetic bacterium Chiorobium limicola f. thiosulfatophilum, ascorbate, N,N,N′,N′-tetramethyl-p-phenylene-diamine, dithioerythritol, an oxygen scavenging mixture, either methyl viologen (MV) or clostridial ferredoxin (CPS Fd) as electron carrier, and either CPS hydrogenase or platinum asbestos as catalyst. All components are necessary for maximum activity, and spinach Fd cannot be substituted for CPS Fd. Higher rates of photohydrogen production are obtained using MV or CPS Fd with hydrogenase than with MV and Pt asbestos. The highest quantum efficiencies (7–10% at 0.2–0.9 mW absorbed light and over 20% at lower light) were obtained with CPS Fd, hydrogenase and non-saturating 812 nm light. With saturating white light, however, rates of photohydrogen production varied relatively little among the various combinations of electron carrier and catalyst tested. The reaction rate is unaffected by 0.03% Triton X-100, and is insensitive to treatment with antimycin a or m-chloro-carbonyl cyanide phenylhydrazone. This indicates that neither electron flow through an endogenous cyclic chain, nor maintenance of a proton gradient are involved in this process.