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The article focuses on comprehensive description of the underlying factorial structure of Helsinki, Finland, social ecology. The original twenty-variable matrix was modified by elimination of three variables to reduce redundancy and by the addition of twenty-five variables to add relevant detail. The resulting variables were intercorrelated, factored, and rotated to produce a forty-two-variable, six factor orthogonal factor matrix. This matrix is the basis for the testing of several hypotheses and for a summary interpretation of Helsinki ecological structure. The methodological Hypothesis 1 to be tested is that ecological factors are invariant under addition of variables. Four substantive hypotheses, set forth in the original statement of the research design and refined by insights gained from the analysis the twenty-variable factor matrix, may be specified. Methodologically, the author concluded that the general invariance of ecological factors under substitution, addition, and subtraction of variables is established by the Helsinki data. The author found that Helsinki's social ecology is well described by a factor model which identifies six fundamental dimensions in the differentiation of the city's residential areas.

A halophilic bacterium was isolated from bottom sediment from the Dead Sea. The organism possessed the properties of the halobacteria, but differed from the known species in two important respects, 1) the cells were disc-shaped and often cupped when grown under optimum conditions, 2) the optimum requirements for sodium chloride was in the range 1.7-2.5 molar which is about half of that generally reported for the halobacteria. The organism was assigned to the genus Halobacterium and described as Halobacterium volcanii spec.nov. The optimum sodium chloride concentration for growth was close to that found in the Dead Sea. The tolerance for magnesium chloride was very high; the organism grew well in media containing magnesium chloride in the concentrations found in the Dead Sea. Halobacterium volcanii is therefore remarkably well fitted for life in the Dead Sea. [ABSTRACT FROM AUTHOR]

A description is given of efforts to develop an integrated control program for successful pest management of date palms in Israel. Work has been concentrated on biological control of the key pest P. blanchardi, and on alternative control operations for the remaining pests. The fact that date fruit is concentrated in bunches was used successfully to enable efficient control of fruit pests with only little interference with the biological control of P. blanchardi. The integrated control program has resulted in a drastic decline of the P. blanchardi population and in successful and easy control of the other pests. [ABSTRACT FROM AUTHOR]

Epidemics of Sphaerotheca fuliginea on squash in growth chambers developed somewhat better under dry than under humid conditions. The reason appeared to be the differing effects of humidity on the various stages of disease development: dryness favored processes of colonization, sporulation and dispersal, while high humidity favored infection and conidial survival. However, all these processes will occur under conditions of humidity far from their respective optima, thus enabling the development of S. fuliginea under widely dissimilar conditions. Information is presented on the effects of temperature on colonization and sporulation. [ABSTRACT FROM AUTHOR]

The effect of improving the environment may be greater inequities in our society. Current environmental programs maintain this inequity, proposed environmental programs may make things worse, and even if we do improve the environment, contentment may decrease. A political coalition of environmental and equity enthusiasts may provide a viable way out of these dilemmas. [ABSTRACT FROM AUTHOR]

Differences in the distribution of population within and across metropolitan areas are seen as a product of the development of the metropolis during different transportation epochs. Age cohorts of census tracts in Cleveland, Ohio, may be split into three groups of development patterns based on the time of their early development: (1) before the development of the automobile, (2) during the early period of the auto's diffusion to the population, and (3) during the period of the mass diffusion of the auto. Patterns of population concentration and congestion across metropolitan areas are heavily selective of places with large population growth before the development of the streetcar and the automobile. More recent population growth has had little effect on population congestion but has led to a deconcentrated metropolis. [ABSTRACT FROM AUTHOR]

Theoretical propositions from human ecology are used to develop a model that explains the centralization or decentralization of various types of families, such as married couples with children, in the Cleveland, Ohio, Metropolitan Area. The model shows how proximity to the Central Business District affects neighborhoods in terms of three characteristics: Age or period of development, both internal and external housing Space, and Site features such as industrial and recreational activity. These structural characteristics are seen, in turn, as the causes of the location of families in relationship to the center of Cleveland. Of the three characteristics, Space generally plays the most important and Site the least important role in determining the location of types of families. However, the location of most types of families is affected by a variety of interrelation- ships among neighborhood characteristics. [ABSTRACT FROM AUTHOR]

Studies in factorial ecology have typically used the principal factor procedure coupled with varimax rotation. Since it can be shown that the results one obtains vary according to the factor and rotation models he employs, and since there is no one "best" way of obtaining initial and derived factor solutions, it is proposed that future research in the area adopt an approach involving the simultaneous use of several different computing algorithms for obtaining initial solutions and both orthogonal and oblique rotation procedures to avoid the possibility that the results one obtains are not method-dependent. Ideally, the factor models employed should differ maximally with respect to the principles upon which they are based. If one finds a given factor regardless of the method he uses, only then can he assert with any confidence that it is not an artifact of his method. Factorial ecologists are often interested in computing "factor scores", but "true" factor scores are not uniquely computable; they can only be estimated. Since the proposed research strategy involves using either a component or an image model, in which the corresponding scores are exact and uniquely computable, the factor score problem is, in a sense, solved. Next it is suggested that, by using orthogonal solutions, factorial ecologists may be overlooking a very important piece of information-the correlation between the factors. There is some reason to believe that this varies from city to city, and may account for the fact that some factors which emerge in studies of Western cities are sometimes not found in cities elsewhere. Some comments are also made on the value of using census tract data, and on the availability of computer programs for different initial and derived factor solutions. [ABSTRACT FROM AUTHOR]

The article focuses on the use of models in the study of demography. Demography has made some progress in developing and applying models. This discipline has been greatly influenced by demand for prediction of future population and by efforts of its experts to satisfy that demand. Population prediction is a perpetual motion, a trisection. Except when the trends are smooth it is likely to fail. But the attempt to predict has inspired many of the demographic models that one now possesses. Such models permit experiments out of which one obtains causal knowledge; they explain data; they focus research by identifying theoretical and practical issues; they systematize comparative study across space and time; they reveal formal analogies between problems that on their surface are quite different; they even help assemble data. There may be circumstances in which the conditional prediction is more helpful than the concrete prediction of what will really happen. The main technical difficulty here arises from effects associated with the proposed change--for example, the effect that the elimination of heart disease would itself have on death rates from other causes.

Focuses on the possible ecological results of continuing development of the world economy in Latin America. Position in nature of man from the beginning of the agricultural revolution to the 19th century; Contribution of rapid population increase to the economic development in the poor countries; Effect of the rapid growth of population on the industrialization.