The relationships of character strengths with coping, work-related stress, and job satisfaction

Personality traits have often been highlighted to relate to how people cope with stressful events. The present paper focuses on character strengths as positive personality traits and examines two basic assumptions that were derived from a core characteristic of character strengths (i.e., to determine how individuals deal with adversities): (1) character strengths correlate with coping and (2) buffer the effects of work-related stress on job satisfaction. Two different samples (i.e., a mixed sample representing various occupations [N = 214] and a nurses sample [N = 175]) filled in measures for character strengths, coping, work-related stress, and job satisfaction. As expected, intellectual, emotional, and interpersonal strengths were related to coping. Interpersonal strengths played a greater role for coping among nurses, as interactions with others are an essential part of their workday. Furthermore, intellectual strengths partially mediated the negative effect of work-related stress on job satisfaction. These findings open a new field for research on the role of personality in coping with work-related stress. Character strengths are trainable personal characteristics, and therefore valuable resources to improve coping with work-related stress and to decrease the negative effects of stress. Further research is needed to investigate this assumed causality.

Theory for the change of bond character in divalent-metal clusters

To determine the size dependence of the bonding in divalent-metal clusters we use a many-electron Hamiltonian describing the interplay between van der Waals (vdW) and covalent interactions. Using a saddle-point slave-boson method and taking into account the size-dependent screening of charge fluctuations, we obtain for Hg_n a sharp transition from vdW to covalent bonding for increasing n. We show also, by solving the model Hamiltonian exactly, that for divalent metals vdW and covalent bonding coexist already in the dimers.

Photoperiod-dependent plasticity of circadian pacemaker center in the brain of the Madeira cockroach Rhyparobia maderae

To various degrees, insects in nature adapt to and live with two fundamental environmental rhythms around them: (1) the daily rhythm of light and dark, and (2) the yearly seasonal rhythm of the changing photoperiod (length of light per day). It is hypothesized that two biological clocks evolved in organisms on earth which allow them to harmonize successfully with the two environmental rhythms: (1) the circadian clock, which orchestrates circadian rhythms in physiology and behavior, and (2) the photoperiodic clock, which allows for physiological adaptations to changes in photoperiod during the course of the year (insect photoperiodism). The circadian rhythm is endogenous and continues in constant conditions, while photoperiodism requires specific light inputs of a minimal duration. Output pathways from both clocks control neurosecretory cells which regulate growth and reproduction. This dissertation focuses on the question whether different photoperiods change the network and physiology of the circadian clock of an originally equatorial cockroach species. It is assumed that photoperiod-dependent plasticity of the cockroach circadian clock allows for adaptations in physiology and behavior without the need for a separate photoperiodic clock circuit. The Madeira cockroach Rhyparobia maderae is a well established circadian clock model system. Lesion and transplantation studies identified the accessory medulla (aMe), a small neuropil with about 250 neurons, as the cockroach circadian pacemaker. Among them, the pigment-dispersing factor immunoreactive (PDF-ir) neurons anterior to the aMe (aPDFMes) play a key role as inputs to and outputs of the circadian clock system. The aim of my doctoral thesis was to examine whether and how different photoperiods modify the circadian clock system. With immunocytochemical studies, three-dimensional (3D) reconstruction, standardization and Ca2+-imaging technique, my studies revealed that raising cockroaches in different photoperiods changed the neuronal network of the circadian clock (Wei and Stengl, 2011). In addition, different photoperiods affected the physiology of single, isolated circadian pacemaker neurons. This thesis provides new evidence for the involvement of the circadian clock in insect photoperiodism. The data suggest that the circadian pacemaker system of the Madeira cockroach has the plasticity and potential to allow for physiological adaptations to different photoperiods. Therefore, it may express also properties of a photoperiodic clock.

Meshing highly regular structures: The case of super carbon nanotubes of arbitrary order

Mesh generation is an important step inmany numerical methods.We present the “HierarchicalGraphMeshing” (HGM)method as a novel approach to mesh generation, based on algebraic graph theory.The HGM method can be used to systematically construct configurations exhibiting multiple hierarchies and complex symmetry characteristics. The hierarchical description of structures provided by the HGM method can be exploited to increase the efficiency of multiscale and multigrid methods. In this paper, the HGMmethod is employed for the systematic construction of super carbon nanotubes of arbitrary order, which present a pertinent example of structurally and geometrically complex, yet highly regular, structures. The HGMalgorithm is computationally efficient and exhibits good scaling characteristics. In particular, it scales linearly for super carbon nanotube structures and is working much faster than geometry-based methods employing neighborhood search algorithms. Its modular character makes it conducive to automatization. For the generation of a mesh, the information about the geometry of the structure in a given configuration is added in a way that relates geometric symmetries to structural symmetries. The intrinsically hierarchic description of the resulting mesh greatly reduces the effort of determining mesh hierarchies for multigrid and multiscale applications and helps to exploit symmetry-related methods in the mechanical analysis of complex structures.