A Stochastic Model for Population and Well-Being Dynamics

This article presents a stochastic dynamic model to study the demographic evolution per sexes and the corresponding well-being of a general human population. The main model variables are population per sexes and well-being. The considered well-being variable is the Gender-Related Development Index (GDI), a United Nations index. The model's objectives are to improve future well-being and to reach a stable population in a country. The application case consists of adapting, validating, and using the model for Spain in the 2000–2006 period. Some instance strategies have been tested in different scenarios for the 2006–2015 period to meet these objectives by calculating the reliability of the results. The optimal strategy is “government invests more in education and maintains the present health investment tendency.”     

The treatment of the spin coupling in the bonding of NO to the Ni-doped MgO (100) surface

The results are reported of density functional theory (DFT) and explicitly correlated wave-function (CASSCF and CASPT2) calculations on the bonding of NO with the Ni-doped MgO(100) surface. The surface is represented by means of a cluster of ions embedded in point charges. A comparison is made between unrestricted (spin polarized) and spin restricted approaches. While the geometry of the surface complex is described in quite an accurate way by a spin unrestricted DFT approach, e.g., using the B3LYP functional, the spin distribution does not correspond to that of the real physical situation. In fact, the spin polarized DFT treatment shows three unpaired electrons, two with spin up and one with spin down, while EPR experiments show clearly the existence of a single spin localized on an Ni 3d shell. A spin restricted B3LYP treatment, on the other hand, gives a correct spin distribution and geometry but fails in reproducing the adsorption energy. Other exchange-correlation functionals behave in a similar or even worse way. The CASPT2 results, by contrast, are in substantial agreement with the experiment, showing the importance of treating on the same footing the spin and electron correlation as well as the multi-configuration character of the wavefunction.     

The Science of Art

Global heat balances with biomass production for aerobic and anaerobic biodigestion of organic matter are proposed. These balances nicely illustrate the thermodynamic differences between these two kinds of biodigestion, and illustrate, in a simple way, a landfills potential for recycling energy originally contained in waste.     

THE ROLE OF HEMOGLOBIN IN THE PHOTOTAXIS OF THE NEMATODE Mermis nigrescens

Abstract A dense zone of crystalline hemoglobin in the head has been presumed to be involved in the photosensitivity of Mermis. With the aim of identifying its role, we have studied the wavelength dependence of the phototaxis. Measuring phototaxic efficiency at constant photon fluence rate (intensity), we find that the spectral response curve is approximately fiat from 350–540 nm and falls to an insignificant level by 580 nm. This is unlike the absorptance (fraction absorbed) spectrum of the hemoglobin pigmentation. Also, fluence-rate/response curves at 420 and 500 nm occur at the same fluence rates even though these wavelengths correspond to a maximum and a minimum of hemoglobin absorption. These results prove that the hemoglobin cannot be functioning as the visual pigment in phototaxis but, for reasons discussed, they neither confirm nor rule out a role as a shadowing pigment. The results are consistent with a shadowing role in the presence of contrast enhancement by the nervous system.
A steep fluence-rate dependence suggests that contrast enhancement does occur in Mermis phototaxis. The 420 or 500 nm fluence rate for half-maximal response is 6 times 10 photons s^-1 cm^-2 (about equivalent in effectiveness to pre-dawn twilight). The wide range of sensitivity, 350–560 nm, has interesting implications as to the nature of the visual pigment.
†NATO reaearch collaborator a n leave from the Department of Biophysics. Laboratorium voor Algemene Natuurkunde, Rijksuniversiteit Groningen, Westersin-gel 34. 9718 CM Groningen, The Netherlands.     

INTRACELLULAR LOCALIZATION OF A CHALCOGENAPYRYLIUM DYE PROBED BY SPECTROSCOPY AND SITES OF PHOTODAMAGE

Site(s) of intracellular localization of a photosensitizing chalcogenapyrylium dye were assessed using murine leukemia cells in culture. While the dye exhibited substantial dark toxicity, additional damage was elicited by irradiation. The fluorescence emission spectrum of intracellular dye suggests an initial moderately hydrophobic site of localization (dielectric constant approx. 20). This might represent a membrane interface. But longer incubations led to alterations in both fluorescence emission and absorbance spectra, indicative of both dye migration to a more hydrophilic cellular site and dye biotransformations. Dye-induced cytotoxicity, in either light or dark, was associated with mitochondrial, rather than membrane damage.     

INTRAMOLECULAR FLUORESCENCE QUENCHING IN COVALENT ACRYLAMIDE-INDOLE ADDUCTS

Abstract— Indole derivatives have been prepared which have a covalently linked quencher, acrylamide. One of these adducts, N-acrylyltryptamine, has a flexible linkage and the other, N-acrylyl-1,2,3,4-tetrahydropyridoindole, has a rigid bridge between indole and the quencher. The intensity decays of these adducts were obtained using multi-frequency phase and modulation fluorometry. The fluorescence of these adducts appears to be dynamically quenched; dominant lifetimes of 64 ps and 31 ps are found for the flexible and rigid adducts. This indicates that very rapid intramolecular quenching occurs, even when the quencher and fluorophore cannot collide. Quenching in the rigid molecule probably involves electron transfer through two sigma bonds. Anisotropy decay data were also collected and rotational correlation times of 62 ps and 163 ps are reported for the flexibile and rigid adducts, respectively.     

A Survey of Aluminum Speciation in the Forest-Well Drainage Water from the Rhode River Watershed

In the Chesapeake Bay Region, acidic atmospheric deposition has deleterious effects on watershed and freshwater ecosystems. One of the associated effects is the disappearance of fish from the streams.     

An asymptotic analysis of two algorithms for certain Hadamard finite-part integrals

Two algorithms for the approximate evaluation of certain Hadamardfinite-part integrals, which date back to Grünwald (1867),have been analysed. It is shown that the quadrature sums areclosely related to the finite-part integrals of the Bernsteinpolynomials. The stability of the algorithms is considered andtwo numerical examples are given.     

Uniqueness Theorems for the Inverse Problem of Acoustic Scattering

Uniqueness theorems are obtained for the problem of determiningthe shape of a sound-soft or sound-hard obstacle from a knowledgeof (1) the far-field pattern at a fixed value of the wave numberand a finite number of distinct incident fields, or (2) thetotal scattering cross section for an interval of wave numbersand the incident field propagating in an arbitrary direction.