California's population geography: lessons for a fourth grade class

Purpose of this paper is to present a model for teaching fourth grade children some aspects of the population geography of California from a nontextual approach. The objective is to interest and instruct children in the mobility of the people, and on the reasons why so many families have moved to California from other states. Students should be alerted not only to internal migration problems, but to the excess of births over deaths. Materials necessary for the lessons are transparencies, overhead projector, marking pencils, chalk and chalkboard. After showing the students that California population has approximately doubled every 20 years, the students should be encouraged to find reasons explaining why people have moved to the state, should be able to categorize those reasons under the terms industrial/manufacturing, agricultural, urban or recreational, should learn how to plot population distribution on a California regional outline map, and should attempt to explain why certain parts of California are more popular than others. The teaching model described in this paper may be replicated with modfications for any grade level and area of study.     

Regular precessions of a gyrostatic satellite in a circular orbit

In the present paper, the regular precessions about the mass center are studied, for a Volterra-type gyrostatic satellite in a circular orbit under a Newtonian force field. All the possible regular precessions are determined.     

TheF N method for solving radiative-transfer problems in plane geometry

TheF _N method of solving problems in radiative transfer for plane-parallel media with anisotropic scattering is established. The method utilizes properties of the exact solution and leads to final equations that are particularly concise and easy to use.     

A new model for X-ray emission from NGC 4151

We present an analysis of the reported spectral features of NGC 4151 in X-rays. It is shown that the origin of X-rays from the source is inconsistent with a single production mechanism. We suggest a new two-component model in which soft X-rays arise from the black-body emission of a tiny hot nucleus withT2×10⁷ K and the hard X-ray photons are generated in an extended region by inverse Compton scattering of electrons with the infrared photons.     

A generalized approach to the evaluation of reflection effects in close binary systems

A convenient integral formulation (-integrals) proves useful in describing reflection effects where there is an axisymmetric illumination, and the form of the emergent intensity distribution of the reflected component can be approximated by a cosine series. The formulation is applied to close binary systems where theoretical curves for the reflected light variation are considered. The treatment proceeds to the fifth power in the fractional dimensions — i.e. including combination of the leading terms of reflection with physical distortion of the components — and is therefore consistent with the usual first order theory of photometric proximity effects in close binary systems.     

A trough cross-stratified glaucarenite: a Cambrian tidal inlet accumulation

The upper part of the Riley Formation, Cambrian of central Texas, is primarily composed of a sequence of thoroughly trough cross-stratified deposits. The dominant lithologies range from fossiliferous glaucarenite to highly glauconitic bio-sparrudite. These cross-stratified deposits accumulated within a tidal inlet and associated lagoonal tributary and distributary channels. Tidal inlet-fill strata are underlain by shallow, open marine oosparites and biomicrites and are overlain by parallel bedded glaucarenites which accumulated as part of a barrier island complex. The parallel bedded deposits exhibit large scale, gently inclined strata, ripple cross-stratification, and a minor amount of vertical burrows. Some glaucarenite units within the tidal inlet-fill have local concentrations of skeletal material, primarily trilobite carapaces. These concentrations are most abundant in the bottoms of troughs. Cementation by bladed to fibrous spar between the carapaces has resulted in the nodular appearance of these skeletal accumulations. Calcite clasts, with relict evaporite textures, occur within the carbonate nodules and surrounding glaucarenite. These clasts were eroded from the shallow subsurface of the barrier island as the tidal inlet migrated. The presence of the former evaporite clasts attest to an arid climate at the time of their formation.     

The evolution of massive close binaries

The results of evolutionary computations for massive binary systems (initial masses of the primary 10M ) with mass ratios between 0.3 and 0.8 are summarized and compared with observations in order to verify how far one can go with the conservative assumption of mass exchange. It is found that conservative mass exchange leads to acceptable first-order models of W-R and massive X-ray binaries. However, the comparison between this theory and observation reveals that for the observed systems (W-R and X-ray binaries) a preference exists for low intial mass ratios; moreover, the X-ray luminosities of the theoretical models are systematically too low, though this may be due to the adopted wind model. In addition, the influences of several parameters (distance between the components, chemical composition, primary mass, mass ratio and atmosphere) are examined. These parameters influence the remnant mass and any further evolution only marginally. Attention is also given to the effect on the system parameters of a supernova explosion of the remnant of the mass-losing component. For a large range of systems a disruption probability smaller than 25% is found.     

Cooling rates of seven hexahedrites

Cooling rates for seven hexahedrites, (Uwet, Coahuila, Walker County, Lombard, Quillagua, Hex River Mountains and Tocopilla) have been determined using a ternary diffusion controlled phase growth analysis developed by the authors. The model is applied to the exsolution and growth of plate phosphides in the kamacite phase of hexahedrites during cooling of the meteorite in its parent body. The effects of cooling rate, bulk composition, nucleation temperature and diffusion field length are considered. A unique cooling rate was determined by comparing the Ni content and width of several phosphides in a given hexahedrite to computer-generated curves of Ni content vs phosphide width. Six hexahedrites have cooling rates of approximately 2°C/10⁶yr. One hexahedrite, Coahuila, has a somewhat higher cooling rate of 10°C/10⁶ yr. These cooling rates fall within the range calculated by an independent method for octahedrites. The cooling rate analysis indicates that the hexahedrites, except for one possible exception, were formed in or close to the core of a parent body ~ 150 km in radius.     

Solution thermochemistry of humic substances—I. Acid-base equilibria of humic acid

The technique of titration calorimetry has been used to characterize the acidic functional groups of humic acid. Both the concentrations of acidic functional groups and the thermodynamic parameters (pK_a, ΔH_a, etc.) for ionization of these functional groups were determined. The calculated values confirm the generally accepted opinion that humic acid contains both carboxyl and phenolic hydroxyl groups. Furthermore, at least one-third of the phenolic hydroxyl groups are not ortho to carboxyl groups and thus cannot participate in chelation of metal ions via salicylate-like complexing sites. The nature of the remaining two-thirds of the phenolic hydroxyl groups is still unknown.     

Tectonics and sedimentation a century later

This paper is one of a series that commemorates the fiftieth anniversary of the founding of the Society of Economic Paleontologists and Mineralogists in 1926. At that time, thought about tectonics and sedimentation was dominated by the ruling hypothesis of continental accretion. Marginal geosynclines were thought to have been filled with sediments derived from borderlands of Precambrian rocks, and then welded tectonically to the continent. In the 1930s, the fundamental distinction noted by Bailey and Jones between graded graywacke- graptolitic slate suites and cross-bedded sandstone-shelly carbonate suites provided a prelude to Krynine's petrographic-tectonic sandstone clans. In the 1940s sedimentary petrography finally emerged from its heavy mineral era to broaden its vistas. Prior notions of evolutionary successions of sediment types linked to a supposed tectonic cycle (e.g. the European ophiolite-flysch-molasse sequence) became more explicit. Refinements of sandstone classifications by Folk, Pettijohn, Gilbert and others, coupled with Krynine's tectonic cycle and the stratigraphic syntheses of Krumbein, Sloss, Dapples, and others, led in the 1940s to the belief that tectonics is the ultimate sedimentary control.Meanwhile the geosyncline had been dissected by Stille and Kay (1936–1951). Ideas about sources of geosynclinal sediments and paleogeography were revised to include volcanic islands and tectonic lands raisedwithin geosynclines rather than borderlands of Precambrian rocks standing outside the geosynclines. In the 1950s and 1960s, sedimentologists exploited the turbidity current revolution and the combined paleocurrent-petrographic approach pioneered by Pettijohn to delineate in detail the paleography and provenances of orogenic belts. Provenance studies have recently reached a high level of sophistication thanks to the efforts of many workers (e.g. Blatt, Crook, Dickinson, Füchtbauer, McBride, Schwab, Suttner, etc.). This work has demonstrated clearly that the cratonic, volcanic and tectonic source land types proposed by Kay had all been important, but to varying degrees at different times and places. When plate tectonics arrived in the late 1960s, sedimentologists were all equipped to reinterpret their rocks using petrographic, paleocurrent and sedimentary structure analyses to help diagnose different types of plate boundaries and to aid in making palinspastic plate restorations. Thus the study of tectonics and sedimentation is alive and thriving a century later.