Proportions,sums and ratios

Data that are proportions arise frequently in all areas of the sciences and engineering. In this paper, the exact distributions of R=X+Y and W=X/(X+Y) and the corresponding moment properties are derived when X and Y are proportions and arise from the most flexible bivariate beta distribution known to date. The associated estimation procedures are developed. Finally, an application is illustrated to compositional data of lavas from Skye.     

E. Digby Baltzell: Moral Rhetoric and Research Methodology

The ways in which values are assimilated to social research differ according to the theoretical frame of reference informing the research. An example from the writings of E. Digby Baltzell illustrates how a moral commitment shaped his assumptions about the nature of the social matrix and his research strategies. A Western moral rhetoric fares well if the researcher chooses a methodologically individualist framework. The framework assists a moral rhetoric by providing it with concrete rather than abstract social actors and with a basis for explanation in terms of motive rather than situational forces. Along the way moral statements can appear in the form of empirical generalizations and historical laws. Should sociologists deem ethically neutral social research desirable, this study suggests that concentration on scientific method, without exploring the value bases for selecting a frame of reference, is not a promising approach. A value analysis, especially around Weber's "value relevance," may function propaedeuticly.     

Environmental hazard and migration intentions in a coastal area in Ghana: a case of sea flooding

Recently, there has been significant debate about whether ‘environmental migration’ can constitute a form of adaptation to environmental change, as opposed to forced or flight migration. The Foresight Report on Migration and Environmental Change (2011) suggested environmental factors are one driver of migration, as well as political, social, economic and demographic drivers, and that—under the right conditions—migration can be a form of adaptation to changing climatic conditions. However, this is dependent on migrants having adequate social and financial capital to undertake beneficial types of migration; it further argues that environmental change may result in ‘trapped populations’ whereby people who lack the necessary resources to re-establish livelihoods elsewhere may be left exposed to increasingly severe environmental shocks and stresses in situ. Research on the climate-migration nexus in West Africa has largely focused on out-migration from the semi-arid Sahel with more limited evidence about how sea flooding interacts with migration flows. This paper attempts to help fill this knowledge gap. Using data from a representative survey of households across three coastal communities in Ghana’s Volta River Delta, this paper concludes that exposure to sea flooding may not be a primary cause of out-migration as other community, economic and political factors influence migration intentions and decisions. Thus, it is important for planned adaptation interventions to be strengthened in situ to enable households, particularly farming households, sustain their livelihoods.     

A discrete model for the segmentation of chains and strings

A statistical model is presented that can be used to represent a discrete breakage process. It considers a fixed length chain or string made up of n +1 pieces joined together. The chain is stressed at each connection or link andrupture occurs at some of the links. Models are developed to answer the question, “what is the expected proportion of chain segments of a given size?” The model is modified to handle those experiments where only thetotal weight of a given size segment is known. Expressions are obtained for the expected value and variance of the number of segments of a given size. The model is used to predict the expected number of segments which results when a fixed length DNA molecule chain is subjected to carcinogenic agents and is applied to industrial examples.     

WebStress: a web interface to explore a multidatabase bibliographic corpus on occupational stress

A bibliographic study on a multidisciplinary subject, such as occupational stress, requires a multidatabase query facility. Given this, we searched eight databases belonging to different fields (medicine, psychology, etc.) and from different countries. Thus, more than 26000 references on occupational stress were gathered. A bibliographic corpus of this sort is unusable because of the heterogeneous format of the records and the number of duplicate entries. Considering the limitations of commercial programs, we have developed a system, called WebStress, for reformatting the data and removing duplicates. The huge number of references and the research needs of updating and searching have necessitated the addition of several other functions to WebStress. Therefore WebStress comprises a web interface that makes it possible to search the corpus with advanced features (using clustering, a specialized thesaurus on stress and Boolean queries). In addition to the usual bibliographic queries on a specific database such as Medline, WebStress provides bibliometric analysis of the corpus, which might contribute to a detailed analysis on occupational stress in order to highlight the networks of researchers and to find the main topics studied in this area. WebStress is not yet available to researchers in general. It is being further developed, and also permission needs to be obtained from the eight commercial bibliographic databases that it consults.     

Elementany Survey Analysis. Prentice-Hall Methods of Social Science Series. James A. Davis. Englewood Cliffs,N. J: Prentice-Hall, 195 Pages, $3.95. Paperbound

This paper advocates clearer conceptual and operational distinctions in doctoral education based on the professional functions that graduates of doctoral programs are expected to perform. Starting from the premise of educating for professional leadership, it is argued that unless doctoral education for advanced practice is distinguished programmatically from education for knowledge production through research, the quality of the educational product in either function may be seriously compromised. A number of content areas whose inclusion in the curriculum could justify educating for practice functions at the doctoral level are outlined.     

Quota fulfilment and errors in stratification

It is desired to draw a random sample containing specified numbers of individuals from each stratum of a population. First a random sample of size N is chosen from the whole populations and the stratum of each individual ascertained; then any shortfall is made up by selecting individuals with known stratum affiliation. Optimal values of N are sought allowing for cost structure and also the possibility of error in ascertaining the strata to which individuals in the first sample belong.