A Two-Phase Exact Algorithm for MAX-SAT and Weighted MAX-SAT Problems

We describe a two-phase algorithm for MAX-SAT and weighted MAX-SAT problems. In the first phase, we use the GSAT heuristic to find a good solution to the problem. In the second phase, we use an enumeration procedure based on the Davis-Putnam-Loveland algorithm, to find a provably optimal solution. The first heuristic stage improves the performance of the algorithm by obtaining an upper bound on the minimum number of unsatisfied clauses that can be used in pruning branches of the search tree.We compare our algorithm with an integer programming branch-and-cut algorithm. Our implementation of the two-phase algorithm is faster than the integer programming approach on many problems. However, the integer programming approach is more effective than the two-phase algorithm on some classes of problems, including MAX-2-SAT problems.     

The age of exploration and exploitation: Younger-looking leaders endorsed for change and older-looking leaders endorsed for stability

The current contribution extends theorizing on leadership and the exploration–exploitation dilemma using an evolutionary perspective. A theoretical connection is made between the exploration–exploitation dilemma and age-biased leadership preferences for exploratory change versus stable exploitation. For the majority of human evolution our species was semi- or entirely nomadic and the trade-off between exploration versus exploitation had substantial physical- and experience-based requirements which align with leadership opportunities as moderated by age. Thus, given the consistency and importance of correctly assigning leadership for the exploration–exploitation dilemma, human evolution has likely selected for age-biased leadership endorsement. Across three experiments we find that younger-looking leaders are endorsed for times of exploratory change and older-looking leaders for stable exploitation. Further, our results indicated that older leaders are endorsed for leading conservative exploitation of nonrenewable resources and younger leaders for exploration of renewable alternatives (i.e., green leadership). The results introduce an age-biased leadership endorsement hypothesis.     

Analysing partial ranks by using smoothed paired comparison methods: an investigation of value orientation in Europe

Summary. This paper introduces the paired comparison model as a suitable approach for the analysis of partially ranked data. For example, the Inglehart index, collected in international social surveys to examine shifts in post-materialistic values, generates such data on a set of attitude items. However, current analysis methods have failed to account for the complex shifts in individual item values, or to incorporate subject covariates. The paired comparison model is thus developed to allow for covariate subject effects at the individual level, and a reparameterization allows the inclusion of smooth non-linear effects of continuous covariates. The Inglehart index collected in the 1993 International Social Science Programme survey is analysed, and complex non-linear changes of item values with age, level of education and religion are identified. The model proposed provides a powerful tool for social scientists.     

Horticultural Decline in the Vale of Evesham,U.K., 1950–1980

There has been little geographical research on the spatial decline of particular agricultural enterprises. This paper traces the regression of horticulture in the Vale of Evesham since 1950 and shows how spatially the decline has been from the periphery inwards, leaving a distinct ‘core’ of production to the east of Evesham. Reasons for the demise of horticulture, both internal and external to the Vale, are outlined and it is demonstrated how the present plight of this part of the Avon Valley is the result of a complex interplay of economic, social, institutional and physical factors.     

THE SOCIOLOGY OF THE FLUORIDATION CONTROVERSY

Previous studies have explained opposition to fluoridation in terms of misinformation, alienation, or confusion. These studies have several shortcomings stemming from an uncritical attitude toward scientific knowledge. Recent perspectives in the sociology of scientific knowledge provide the basis for developing a wider understanding of the fluoridation issue, including analysis of scientific disagreements, the promotion of fluoridation, and experiences in other countries. Contrary to the usual view, public opposition to fluoridation does not necessarily signify a failure of education or democracy.     

Singapore's Malay-Muslim minority: Social identification in a post-‘9/11’ world

Fundamental within Singapore's modernisation push ‘From Third World to First’ was the long-term strategy of establishing a Singapore identity based on multiracialism, multilingualism, multiculturalism and multireligiousity (the ‘4Ms’). But while wholesale landscape changes have largely removed earlier associations between ethnicity and residence, government promotion of a shared Singapore identity has been frustrated by the lagging educational and socio-economic achievements of Singapore's Malay minority. Prior to the events of ‘9/11’ government concern had centred on the growing popularity of private Islamic schools, or madrasahs, which in the government's view could affect educational standards in the city-state. However, following the destruction of the World Trade Center government attention was quickly shifted to the promotion of ‘racial harmony’ and Singaporeans were urged to ‘get to know your neighbours’ in a tacit admission that 40 years of ‘racial’ assimilation had yet to produce ethnically integrated, cross-cultural community spirit. Subsequent events, particularly the arrest of local Jemaah Islamiyah operatives and the destruction in Iraq, have impacted most strongly upon Singapore's Malay-Muslim community and posed challenges to its identity within a multicultural society.     

Framing and Strategy: Explaining Differential Longevity in the Woman's Christian Temperance Union and the Anti-Saloon League

This study examines the sources of strength and mobilizing impetus in the Anti-Saloon League (ASL) and the Woman's Christian Temperance Union (WCTU) in the early twentieth century. Both the ASL and the WCTU played essential roles in the establishment of national prohibition. The quick demise of the ASL after the repeal of the Eighteenth Amendment in 1933 and the endurance of the WCTU cannot be explained only by the structural conditions that confronted the two movements, as suggested by the resource mobilization approach. Using Snow and Benford's "collective action frame" concept, it is argued that a consideration of meanings constructed by the movements'leaders and their translation into strategic action provides a better account of the temporal viability of the WCTU and ASL. The critical distinction between the WCTU and ASL was in how they framed the "alcohol question." Both the relative success of the WCTU and the failure of the ASL were contingent upon their ability to adapt their rhetoric and corresponding strategies to rapid shifts in the cultural and economic climate of the late twenties and early thirties.