In this project I evaluated the effect of social dominance on reconciliation and forgiveness. Based on studies of nonhuman primates, it was hypothesized that humans would be more likely to accept and reciprocate conciliatory gestures when made by more socially dominant people. It was also hypothesized that the moderating effect of relative dominance on a victim?s decision to forgive would not be as strong as relative dominance?s effect on a victim?s decision to reconcile. This hypothesis was based on the expectation that reconciliation is most essential for gaining access to transgressor-controlled resources. However, conciliatory gestures by less dominant transgressors more effectively elicited forgiveness and reconciliation, as these gestures were evidently more successful at making victims feel safe. Also, relative dominance did not have a greater effect on victims? conciliatory behaviors than on forgiveness.

The effects of unemployment on the genesis of civil conflict are examined as both a social and economic factor, with particular emphasis on civil conflict in ethnically heterogeneous nations. A logit statistical analysis of a data set indicates that increased unemployment rates do contribute to the onset of civil conflict.

Light is one of the environmental signals that regulate axillary shoot development. However, little is known about molecular and physiological mechanisms regulating the development of the axillary shoot in response to light signals. Molecular events associated with the enhanced apical dominance of phytochrome B mutant sorghum (Sorghum bicolor) were analyzed to reveal processes mediating axillary shoot development in response to light. The enhanced apical dominance of phyB-1 mutant sorghum is due to inhibition of bud outgrowth and is accompanied by upregulation of the dormancy-associated gene (SbDRM1) in the buds. Increased expression of the Teosinte Branched1 (SbTB1) gene (encoding a putative transcription factor that represses bud outgrowth) suggests that the inhibition of bud outgrowth in phyB-1 sorghum is due to the absence of active phyB to repress SbTB1. The results were confirmed by growing wild type seedlings at high plant density or with supplemental farred (FR) light that induces enhanced apical dominance. However, the SbTB1 gene is not involved in the inhibition of bud outgrowth induced by defoliation in wild type seedlings. The results indicate variations in molecular mechanisms among different signals inhibiting branching. Increased expression of SbMAX2 (which encodes an F-box protein that represses bud outgrowth) in buds repressed by light and defoliation suggests common mechanisms at the downstream end of pathways inhibiting branching. The expression levels of several cell cycle-related genes including SbPCNA, SbHis4, SbCycD2, SbCycB and SbCDKB were down-regulated in the repressed buds of FRtreated and defoliated seedlings indicating the suspension of cell division in those buds. However, these cell cycle-related genes were continuously expressed in the repressed buds of phyB-1, suggesting that inhibition of bud outgrowth in phyB-1 is not associated with down-regulation of cell cycle-related gene expression. The down-regulation of cell cycle-related genes in the buds of FR-treated wild type seedlings indicates that other sensors, in addition to phyB, regulate bud outgrowth in response to FR enrichment. The approaches used and results achieved will provide direction for future research on this important topic.

Protein oligomerization provides a way for cells to modulate function in vivo. In this study, self-assembling protein fragments from ParC, DnaX, and proteins of unknown function were used to generate phenotypes in a dominant negative manner. These fragments were expressed as Thioredoxin (TRX) fusions under the control of the inducible araBAD promoter. Fragments chosen contain only the oligomerization domain of the protein, lacking the regions necessary for catalytic function. Fragments of ParC, a subunit of Topoisomerase (Topo) IV, generated fragment-specific phenotypes. Regions that expressed both the oligomerization domain and CTD of ParC (ParC206-752 and ParC332-752) yielded filamentous cells with several different nucleoid segregation phenotypes. Another ParC fragment containing only the oligomerization domain of ParC (ranging from 333-485) yields a recA-dependent septation defect in a subset of the population. This phenotype suggests that Topo IV may be inhibiting chromosome dimer resolution. The overexpression of DnaX247-455, a fragment containing regions of both the tau and gamma subunits of the DNA Polymerase III holoenzyme, led to a severe plating defect. Upon further investigation, this fragment caused filamentation, a nucleoid defect, and induction of sulA, similar to the effects seen with the dnaX temperature-sensitive alleles. The overexpression of the various y-protein fragments yielded a variety of mediaspecific plating defects on over 50% of the proteins tested. The overexpression of the protein fragments yielded effects that were not seen by other overexpression or deletion experiments, even under similar growth conditions. The results presented here show that the overexpression of self-assembling fragments yield a variety of dominant negative phenotypes. Reducing the activity of protein complexes allows for new aspects of the physiological process to be investigated.

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It is often desirable to compare risky investments in the context of economic decision theory. Expected utility analyses are means by which stochastic alternatives can be ranked by re-weighting the probability mass using a decision-making agent’s utility function. By maximizing expected utility, an agent seeks to balance expected returns with the inherent risk in each investment alternative. This can be accomplished by ranking prospects based on the certainty equivalent associated with each alternative. In instances where only a small sample of observed data is available to estimate the underlying distributions of the risky options, reliable inferences are difficult to make. In this process of comparing alternatives, when estimating explicit probability forms or nonparametric densities, the variance of the estimate, in this case the certainty equivalent, is often ignored. Resampling methods allow for estimating dispersion for a statistic when no parametric assumptions are made about the underlying distribution. An objective of this dissertation is to utilize these methods to estimate confidence regions for the sample certainty equivalents of the alternatives over a subset of the parameter space of the utility function. A second goal of this research is to formalize a testing procedure when dealing with preference ranking with respect to utility. This is largely based on Meyer’s work (1977b) developing stochastic dominance with respect to a function and more specific testing procedures outlined by Eubank et. al. (1993). Within this objective, the asymptotic distribution of the test statistic associated with the hypothesis of preference of one risky outcome over another given a sub-set of the utility function parameter space is explored.

Much of the previous research on systematic variation in social judgements has focused on attractiveness judgements and factors that are related to inter-sexual competition (reviewed in Chapter 1). By contrast, there has been relatively little work on the extent to which factors that may be more closely related to intra-sexual competition, such as the outcomes of aggressive conflict with own-sex individuals and competition for resources, may have shaped perceptions of potential rivals. Correlational studies showed that indices of men’s (Chapter 2) and women’s (Chapter 4) own dominance were negatively correlated with the extent to which they perceived masculine own-sex individuals to be more dominant than feminine own-sex individuals. These findings suggest that those individuals who are likely to incur more substantial costs if they underestimate the dominance of potential rivals may find cues of others’ dominance (i.e., masculine characteristics) to be particularly salient. Further evidence for this proposal came from priming experiments in which men who were primed with scenarios in which they lost confrontations were more likely to ascribe high dominance, but not trustworthiness, to masculine men’s faces than were men who were primed with scenarios in which they won confrontations (Chapter 3). Further priming experiments suggested that priming women with cues to the sex ratio of the local population (Chapter 5) or priming women’s concerns about resources versus pathogens (Chapter 6) altered the salience of facial cues of others’ attractiveness and dominance. While previous research on systematic variation in social perception has tended to focus on attractiveness judgements and factors related to inter-sexual competition, the findings reported in this thesis highlight the potential importance of dominance perceptions and factors related to intra-sexual competition. Directions for future research, such as establishing whether dominance perceptions predict real world social outcomes, are then discussed (Chapter 7).

Sex-specific calls are used in male-male agonistic encounters and male-female courtship in many animal species. The ring-tailed lemur (Lemur catta) is a gregarious Malagasy strepsirhine with twenty-two distinct vocalizations for adults, including two male-specific vocalizations and an additional vocalization with male-specific functions: the howl, the squeal, and the purr. Proposed intra-sexual agonistic functions for these three vocalizations have never been empirically tested. This study’s purpose was to investigate the functions of howling, squealing, and purring in the ring-tailed lemur, and to assess the relationships between the rates of these vocalizations and male dominance. From March to July 2010, I collected 600 hours of total data and 480 hours of focal data on male ring-tailed lemurs aged three and older at Beza Mahafaly Special Reserve, Madagascar. I observed each male continuously for 30 minutes at a time and noted behaviours including all vocalizations and all agonism using one–zero sampling at 2.5-min intervals. I calculated male dominance rank and vocalization rates from these data. My results indicated that male dominance rank is correlated with male purring rate and with squealing rate, but not with howling rate. Male purring rate increased during intra-sexual agonism and was associated with aggression in agonistic encounters. Squealing rate increased during male-male agonism and indicated both aggression and submission in male-male encounters. Howling rate increased during inter-group encounters and a greater number of males participated in multi-male howling choruses when non-group members were present. Purring and squealing are agonistic vocalizations and used in male-male agonism in the ring-tailed lemur, while howling is used in inter-group encounters.

Sex-specific calls are used in male-male agonistic encounters and male-female courtship in many animal species. The ring-tailed lemur (Lemur catta) is a gregarious Malagasy strepsirhine with twenty-two distinct vocalizations for adults, including two male-specific vocalizations and an additional vocalization with male-specific functions: the howl, the squeal, and the purr. Proposed intra-sexual agonistic functions for these three vocalizations have never been empirically tested. This study’s purpose was to investigate the functions of howling, squealing, and purring in the ring-tailed lemur, and to assess the relationships between the rates of these vocalizations and male dominance. From March to July 2010, I collected 600 hours of total data and 480 hours of focal data on male ring-tailed lemurs aged three and older at Beza Mahafaly Special Reserve, Madagascar. I observed each male continuously for 30 minutes at a time and noted behaviours including all vocalizations and all agonism using one–zero sampling at 2.5-min intervals. I calculated male dominance rank and vocalization rates from these data. My results indicated that male dominance rank is correlated with male purring rate and with squealing rate, but not with howling rate. Male purring rate increased during intra-sexual agonism and was associated with aggression in agonistic encounters. Squealing rate increased during male-male agonism and indicated both aggression and submission in male-male encounters. Howling rate increased during inter-group encounters and a greater number of males participated in multi-male howling choruses when non-group members were present. Purring and squealing are agonistic vocalizations and used in male-male agonism in the ring-tailed lemur, while howling is used in inter-group encounters.

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