Some applications of graph theory to clustering

This paper attempts to review and expand upon the relationship between graph theory and the clustering of a set of objects. Several graphtheoretic criteria are proposed for use within a general clustering paradigm as a means of developing procedures in between the extremes of complete-link and single-link hierarchical partitioning; these same ideas are then extended to include the more general problem of constructing subsets of objects with overlap. Finally, a number of related topics are surveyed within the general context of reinterpreting and justifying methods of clustering either through standard concepts in graph theory or their simple extensions.     

Fluctuating emotions: relating emotional variability and job satisfaction

This study focuses on the relation between emotional variability and job satisfaction and examines emotional exhaustion as a potential explanation for why variability may result in lower satisfaction. In addition, this study examines organizational identification as a potential moderator of the relation between emotional exhaustion and job satisfaction. A total of 244 nonacademic staff in two universities in Ecuador responded to the surveys. The results demonstrated that emotional exhaustion mediated the relation between emotional variability and job satisfaction and that organizational identification weakened the negative relation between emotional exhaustion and job satisfaction. This research is among the first to investigate emotional variability in organizations and examine the role of organizational identification in buffering the negative effect of emotional variability.     

Happiness and life satisfaction in Rwanda

This study investigated predictors of happiness and life satisfaction in Rwanda. Data from the World Values Survey and gathered from 3 030 Rwandese (age ranging 16 to 90 years, mean age = 34.2, SD = 12.7; females = 50.5%) were pooled for the analysis. For the comparison, international World Values Survey data were utilised. A fixed effects multilevel regression model was used to predict happiness and life satisfaction from gender, health, socio-economic, and some subjective measures. Males had greater self-rated happiness and life satisfaction scores than females. State of health and sense of freedom of choice predicted both happiness and life satisfaction. Valuing of friends, weekly religious attendance, and national pride positively predicted happiness, whereas household’s financial satisfaction, full-time employment, high-income group, being a student, and sense of trust predicted life satisfaction. This study suggests that health status, household’s financial satisfaction and emancipative values could maximise subjective well-being in Rwanda.     

Interaction of Recruiter and Applicant Gender in Resume Evaluation: A Field Study

In the present study, we examined the effect of recruiter and applicant gender on recruiters' evaluations of applicants' qualifications as reported on actual applicant resumes. Forty recruiters evaluated applicant resumes that were randomly allocated to them. In total, 388 recruiter evaluations of applicant resumes comprised the sample. Results indicate that recruiter and applicant gender interacted to predict recruiters' perceptions of applicants' qualifications. Male recruiters' perceptions of applicants' work experiences did not differ depending on applicant gender. However, female recruiters perceived male applicants' resumes to report more work experiences than resumes of female applicants. Furthermore, male recruiters perceived female applicants as having more extracurricular interests than male applicants. Female recruiters rated both male and female applicants as having about the same amount of extracurricular activity information on their resumes. Gender role theory provides a possible explanation for the study's findings.     

So what do you think of the organization? A contextual priming explanation for recruitment Web site characteristics as antecedents of job seekers’ organizational image perceptions

Although job seekers’ organizational image perceptions can influence attraction to recruiting organizations, little is known about how these perceptions are formed or modified. To address this research gap, the authors drew from research in social cognition theory and demonstrated that recruitment Web site characteristics influenced the development and modification of organizational image perceptions via a priming mechanism. Results of two studies showed that having technologically advanced Web site features and depicting racially diverse organizational members served as contextual primers and influenced participants’ organizational image perceptions. Results also revealed that participants’ familiarity with recruiting organizations moderated the effects of these Web site characteristics on several dimensions of organizational image such that effects were weaker for more familiar organizations. These findings suggest that organizations can manage job seekers’ organizational image perceptions through strategic recruitment Web site design; however, such attempts may be tempered by job seekers’ familiarity with the organization.     

Internetbasierte Vorbereitung auf eine station?re psychosomatisch-psychotherapeutische Behandlung

Background

Encouraged by promising results of online aftercare programs, this study adapted the concept of internet-based minimal interventions in order to use the time between referral and actual admission to inpatient treatment. The online intervention includes information about the hospital and the treatment and sections which aim to enhance motivation, provide support and allow contact.

Methods

A comprehensive cohort study was conducted with 379 participants in the randomized subcohort. Primary endpoint was the speed of change of the physical, mental and social impairment and of the psychological well-being in the first 2 weeks of inpatient treatment as well as the rates of reliable change 2 weeks after admission.

Results

Both the control and intervention group of the randomized subcohort showed statistically significant improvements in health status. No significant difference in the rate of change was found. The degree of achieved improvement in the physical impairment was equal to the expected intervention effect. A difference in the rates of change was found for the psychological well-being: the intervention group showed 19% more reliable improvements.

Conclusions

The study design and the contents of the intervention were accepted by the patients. The internet-based intervention can help to prepare for treatment and to shorten the settling-in period.     

The influence of expertise and of physical complexity on visual short-term memory consolidation

We investigated whether the expertise of a perceiver and the physical complexity of a stimulus influence consolidation of visual short-term memory (VSTM) in a S1-S2 (Stimulus 1-Stimulus 2) change detection task. Consolidation is assumed to make transient perceptual representations in VSTM more durable, and it is investigated by postexposure of a mask shortly after offset of the perceived stimulus (S1; 17 to 483?ms). We presented colours, Chinese characters, pseudocharacters, and novel symbols to novices (Germans) or experts of Chinese language (Chinese readers). Physical complexity was manipulated by the number of strokes. Unfamiliar material was remembered worse than familiar material (Experiments 1, 2, and 3). For novices the absolute VSTM performance was better for physically simple than for complex material, whereas for experts the complexity did not matter-Chinese readers memorized Chinese characters (Experiment 3). Articulatory suppression did not change these effects (Experiment 2). We always observed a strong effect of SOA, but this effect was influenced neither by physical complexity nor by expertise; only the length of the interstimulus interval between S1 and the mask was relevant. This was observed even with short stimulus onset asynchrony (SOA) of 100?ms (Experiment 2) and in comparing colours and characters (Experiment 5). However, masks impaired memory if they were presented at the locations of the to-be-memorized items, but not beside them-that is, interference was location-based (Experiment 6). We explain the effect of SOA by the assumption that it takes time to stop encoding of information presented at item locations with the offset of S1. The increasing resistance against interference by irrelevant material appears as consolidation of S1.     

Sample size planning with the cost constraint for testing superiority and equivalence of two independent groups

The allocation of sufficient participants into different experimental groups for various research purposes under given constraints is an important practical problem faced by researchers. We address the problem of sample size determination between two independent groups for unequal and/or unknown variances when both the power and the differential cost are taken into consideration. We apply the well‐known Welch approximate test to derive various sample size allocation ratios by minimizing the total cost or, equivalently, maximizing the statistical power. Two types of hypotheses including superiority/non‐inferiority and equivalence of two means are each considered in the process of sample size planning. A simulation study is carried out and the proposed method is validated in terms of Type I error rate and statistical power. As a result, the simulation study reveals that the proposed sample size formulas are very satisfactory under various variances and sample size allocation ratios. Finally, a flowchart, tables, and figures of several sample size allocations are presented for practical reference.     

Observed Leadership Potential of Personnel in a Team Setting: Big Five traits and proximal factors as predictors

The authors explored implications of Big Five traits and proximal factors for the observed leadership potential of personnel in newly formed teams. Big Five traits were designated as distal factors having indirect links to observed leadership potential via three proximal factors: individual perception of team cohesion, team‐oriented proactivity, and teamwork knowledge. Drawing from implicit personality theory, the authors introduced a team‐leader personality profile as a higher‐order construct for explaining covariation among extraversion, conscientiousness, and emotional stability. A structural analysis of data from 472 personnel supported hypothesized relationships. Specific findings included validation of a team‐leader personality profile and preliminary support for the measure of team‐oriented proactivity that was developed for this study. Implications of the various findings are discussed.