UNDERSTANDING AND SOLVING AMERICAN URBAN PROBLEMS: GEOGRAPHICAL CONTRIBUTIONS?

The genesis of most urban problems can only be understood in the context of the capitalist global economy in which the geography of development is necessarily countered by a geography of underdevelopment, at all spatial scales. Realization of this fundamental point implies that urban problems can never be solved within a capitalist context, only spatially rearranged. Geographers concerned with inequalities are therefore faced with a dilemma: either they work to redistribute welfare and illfare in the world or they work for the unmasking and replacement of capitalism.     

Instantaneous photochemical rates in the global stratosphere

Starting with the average actual distribution of ozone (Dütsch [15]) and temperature in the stratosphere, we have calculated the solar intensity as a function of wavelength and the instantaneous rates (molecules cm^–3 sec^–1) for each Chapman reaction and for each of several reactions of the oxides of nitrogen. The calculation is similar to that ofBrewer andWilson [5]. These reaction rates were calculated independently in each volume element in spherical polar coordinates defined by R=1 km from zero to 50, =5° latitude, and ø=15° longitude (thus including day and night conditions). Calculations were made for two times: summer-winter (January 15) and spring-fall (March 22). As input data we take observed solar intensities (Ackerman [1]) and observed, critically evaluated. constants for elementary chemical and photochemical reactions; no adjustable parameters are employed. (These are not photochemical equilibrium calculations.) According to the Chapman model, the instantaneous, integrated, world-wide rate of formation of ozone from sunlight is about five times faster than the rate of ozone destruction, and locally (lower tropical stratosphere) the rate of ozone formation exceeds the rate of destruction by a factors as great as 1000. The global rates of increase of ozone are more than 50 times faster thanBrewer andWilson's [5] estimate of the average annual transfer rate of ozone to the troposphere. The rate constants of the Chapman reactions are believed to be well-enough known that it is highly improbable that these discrepancies are, due to erroneous rate constants. It is concluded that something else besides neutral oxygen species is very important in stratospheric ozone photochemistry. The inclusion of a uniform concentration of the oxides of nitrogen (NO_x as, NO and NO₂) averaging 6.6×10^–9 mole fraction gives a balance between global ozone formation and destruction rates. The inclusion of a uniform mole fraction of NO_x at 28×10^–9 also gives a global balance. These calculations support the hypethesis (Crutzen [10],Johnston [24]) that the oxides of nitrogen are the most important factor in the global, natural ozone balance. Several authors have recently evaluated the natural source strength of NO_x in the stratosphere; the projected fleets of supersonic transports would constitute an artificial source of NO_x about equal to the natural value, thus promising more or less to double an active natural stratospheric ingredient.     

Electrical conductivity of molten FeNiSC core mix

The electrical conductivity of liquid (Fe₉₀Ni₁₀)₃S₂ saturated with 2.6 weight percent carbon averages 2.7·10⁵ mho/m at 1000°C and zero pressure. This may imply a slightly lower electrical conductivity for the earth's core than that obtained by extrapolating the properties of pure liquid iron and solid iron alloys to core pressures and temperatures. Although a sulphur-rich core would have a smaller proportion of sulphur, the effect of lowering the sulphur content of the FeNiSC liquid to about 15 weight percent would be unlikely to increase the conductivity above 5·10⁵ mho/m.     

Die Windverhältnisse am Bodensee

Summary Within the programme sponsored by the Deutsche Forschungsgemeinschaft (Bad Godesberg) in which different branches of scientific disciplines cooperated in order to investigate Lake Constance in Southern Germany, meteorology was mainly dealing with the wind situation round the Lake.Investigations by the Aerological Observatory of Friedrichshafen which was destroyed during the last war, yielded fundamental contributions to the problem of air currents on the Lake and in the outer regions of the Alps in its vicinity. With regard to the various problems in the common achievements of the Lake Constance Project of the Deutsche Forschungsgemeinschaft it proved necessary to extend the investigations across the whole region of the Lake in order to elaborate the synoptic situations of the daily and annual periodical wind systems.The vertical structure of the air currents could not be inferred but by an indirect manner, whilst its confirmation by direct aerological means is going to be studied in an additional research programme. The results of the comprehensive observational material of several years will be published in a final report by the Deutsche Forschungsgemeinschaft.Here some special results of the wind observations are presented.     

Les végétaux (Macrofossiles) du crétacé moyen de l'Europe occidentale et du Sahara. Végétations et paléoclimats

Cette note expose un ensemble de synthèses régionales sur les thèmes suivants: les macrofossiles de l'Angleterre; les bois de l'Albien du Boulonnais; les végétaux de Normandie du Crétacé moyen; les milieux forestiers littoraux du Cénomanien inférieur de l'Anjou et des Charentes; les macroflores du Crétacé moyen continental de l'Espagne; les gisements de l'Italie et du Sahara.L'esquisse d'une évolution possible de quelques végétations de ces contrées est proposée, ainsi que les arguments paléoclimatiques que l'on peut en déduire.This paper presents a regional synthesis concerning mid-Cretaceous plant megafossils from England, Normandy, Northern and Western France, Spain, Italy, and the Sahara. A possible evolution pattern is offered for these floras during mid-Cretaceous time; some climatic arguments are presented.     

Objective comparison of mass fragmentograms by principal components analysis: method and results

The multivariate statistical method of Principal Components Analysis is used to classify gas chromatographic-mass spectrometric data. The specific examples comprise sterane and triterpane regions of GC-MS analyses of branched/cyclic fractions. The statistical model provides an objective analogue to visual comparison and classification of mass fragmentograms. Sources of experimental error influencing the statistical results include insufficient sample size, short integration times, and peak skewing. The method successfully groups samples of oils, oil sand, and polluted beach sand according to geographic origin: beach sand groups with type of crude spilled; laboratory biodegraded and untreated Nigerian crudes group together. Applications of three-mode Principal Components Analysis can range from study of geologic processes acting on organic compounds to classification of unknown pollutants.