Matching middle and top managers: Do gender and tenure similarities between middle and top managers affect organizational performance?

This paper studies whether demographic similarities between middle and top managers with different tasks (strategy formation and strategy implementation) impacts organizational performance. By drawing on relational demography theory, we investigate the effect of similarity in gender, organizational tenure, and in both these demographics on the overall costs of Dutch municipalities. The main findings of this paper show that the similarity effects are interrelated: when middle and top managers diverge on only one demographic, performance is increased. Also, when leaders are similar on both demographics, performance is impaired. We conclude by discussing the implications for the literature on middle management, relational demography, and strategy formation and implementation.

Plant Resistance in Some Modern Soybean Varieties May Favor Population Growth and Modify the Stylet Penetration of Bemisia tabaci (Hemiptera: Aleyrodidae)

Complaints of severe damage by whiteflies in soybean fields containing genetically engineered (GE) varieties led us to investigate the role of transgenic soybean varieties expressing resistance to some insects (Cry1Ac Bt toxin) and to herbicide (glyphosate) on the population growth and feeding behavior of Bemisia tabaci (Gennadius) MEAM1 (Hemiptera: Aleyrodidae). In the laboratory, the whiteflies reared on the GE Bt soybeans had a net reproductive rate (R0) 100% higher and intrinsic rate of population increase (rm) 15% higher than those reared on non-GE soybeans. The increased demographic performance was associated with a higher lifetime fecundity. In electrical penetration graphs, the whiteflies reared on the GE soybeans had fewer probes and spent 50% less time before reaching the phloem phase from the beginning of the first successful probe, indicating a higher risk of transmission of whitefly-borne viruses. Data from Neotropical fields showed a higher population density of B. tabaci on two soybean varieties expressing glyphosate resistance and Cry1Ac Bt toxin. These results indicate that some GE soybean varieties expressing insect and herbicide resistances can be more susceptible to whiteflies than non-GE ones or those only expressing herbicide resistance. Most likely, these differences are related to varietal features that increase host-plant susceptibility to whiteflies. Appropriate pest management may be needed to deal with whiteflies in soybean fields, especially in warm regions, and breeders may want to consider the issue when developing new soybean varieties.

Weighing the Evidence for the Abundant-Center Hypothesis

The abundant-center hypothesis posits that species density should be highest in the center of the geographic range or climatic niche of a species, based on the idea that the center of either will be the area with the highest demographic performance (e.g., greater fecundity, survival, or carrying capacity). While intuitive, current support for the hypothesis is quite mixed. Here, we discuss the current state of the abundant-center hypothesis, highlighting the relatively low level of support for the relationship. We then discuss the potential reasons for this lack of empirical support, emphasizing the inherent ecological complexity which may prevent the observation of the abundant-center in natural systems. This includes the role of non-equilibrial population dynamics, species interactions, landscape structure, and dispersal processes, as well as variable data quality and inconsistent methodology. The incorporation of this complexity into studies of the distribution of species densities in geographic or niche space may underlie the limited empirical support for the abundant-center hypothesis. We end by discussing potentially fruitful research avenues. Most notably, we highlight the need for theoretical development and controlled experimental testing of the abundant-center hypothesis.

Profile of Self-Reported Physical Tasks and Physical Training in Brazilian Special Operations Units: A Web-Based Cross-Sectional Study

There is limited research examining the physical tasks that Brazilian special policemen groups can perform in the line of duty. The aims of this study were to (a) identify the occupational tasks of specialist police personnel serving in the Rapid Response Group (GRR) and Tactical Operations Command (COT), and to profile the frequency, difficulty, and importance of these tasks, and (b) to explore the current physical training these special operations police units (SOPUs) officers undertake to maintain their operational fitness. Univariate analysis for numerical variables (mean and standard deviation (SD)), as well as the absolute and relative frequencies for categorical variables were performed. Two Brazilian SOPUs performed a questionnaire with demographic, performance, and physical training sections. A total of 78 respondents (24 of the GRR and 54 of the COT) completed the survey. “Standing and/or sitting with complete equipment for long periods in different climatic conditions”, and “lifting/pushing/pulling heavier objects” were the most frequent and difficult occupational tasks of both SOPUs, respectively. “Shooting a long weapon” and “breaking a door” were the most important for GRR and COT, respectively. All officers undertook regular physical training (~9 h/week), in an unstructured manner, without supervision, and planning of physical training is carried out autonomously (COT) or a mixture of autonomously and directed (GRR), with the main objectives of developing aerobic endurance and muscle strength. It is important that SOPUs teams train their members’ physical capabilities to perform the tasks identified in this study, as well as follow a structured, supervised, and planned physical training program.