Carnegie Institution of Washington publication.

no. 143 (1911)

Carnegie Institution of Washington publication.

no. 198 (1914)

Carnegie Institution of Washington publication.

no. 135 (1910)

Carnegie Institution of Washington publication.

no. 224 (1916)

Carnegie Institution of Washington publication.

no. 273 (1921)

Carnegie Institution of Washington publication.

no. 140 (1911)

Loss of social behaviors by Myxococcus xanthus during evolution in an unstructured habitat

Social behaviors are often targets of natural selection among higher organisms, but quantifying the effects of such selection is difficult. We have used the bacterium Myxococcus xanthus as a model system for studying the evolution of social interactions. Changes in the social behaviors of 12 M. xanthus populations were quantified after 1,000 generations of evolution in a liquid habitat, in which interactions among individuals were continually hindered by shaking and low cell densities. Derived lineages were compared with their ancestors with respect to maximum growth rate, motility rates on hard and soft agar, fruiting body formation ability, and sporulation frequency during starvation. Improved performance in the liquid selective regime among evolved lines was usually associated with significant reductions in all of the major social behaviors of M. xanthus. Maintenance of functional social behaviors is apparently detrimental to fitness under asocial growth conditions.

Genetic control of social organization in an ant

A central issue in evolutionary biology is the extent to which complex social organization is under genetic control. We have found that a single genomic element marked by the protein-encoding gene Gp-9 is responsible for the existence of two distinct forms of social organization in the fire ant Solenopsis invicta. This genetic factor influences the reproductive phenotypes and behavioral strategies of queens and determines whether workers tolerate a single fertile queen or multiple queens per colony. Furthermore, this factor affects worker tolerance of queens with alternate genotypes, thus explaining the dramatic differences in Gp-9 allele frequencies observed between the two social forms in the wild. These findings reveal how a single genetic factor can have major effects on complex social behavior and influence the nature of social organization.

Influence of social problems on management in general practice: multipractice questionnaire survey

Objectives: To find how often social problems influence clinical management in general practice, how management is changed, and how the characteristics of patients, doctors, and the doctor-patient relationship influence this management.

The Affective Dimensions of Social Controversy

Social controversy is a sustained, mediated debate between at least two oppositional parties which is more than just a difference of opinion; rather it is a persistent conflict over the political and cultural implications that dominant forms of communicative reasoning, practices, and norms have for a public. Simply put, during social controversies the norms guiding public life can be negotiated, reaffirmed, negated, and/or transformed. This can lead to progressive political, cultural, and/or social change in some instances, while establishing or reifying conservative and even oppressive norms, practices, and laws in others. Building upon Olson and Goodnight's (1994) theoretical and methodological framework of social controversy, this dissertation argues that scholars should analyze the role affect plays in this type of conflict as a means to address the regulation of public conduct as well as public discourse. The rhetorical and argumentative significance of the affective dimensions of social controversy have been conceptualized and analyzed via an examination of emotion-based claims and affective states that have become salient, discernable and/or apprehendable during specific public disagreements. Such a conceptualization demonstrates that critical insights regarding the norms that guide public conduct, the role risk and vulnerability play in the regulation of individuals' public behavior, and the relationship between affect and citizenship can be gained by focusing on a controversy's affective dimensions. To highlight the importance of the study of affect in social controversy as well as better understand the larger critical significance affect theory has for rhetorical and argumentation studies, this dissertation has analyzed the affective dimensions of three conflicts. They are: the Abu Ghraib prisoner abuse social controversy, the International Freedom Center social controversy, and the controversy over the 2004 French ban on conspicuous religious attire in public schools. The findings from this dissertation that have specific and general implications for future work in the field of controversy as well as rhetoric and argumentation, respectively.