River Networks for Instant Procedural Planets

Realistic terrain models are required in many applications, especially in computer games. Commonly, procedural models are applied to generate the corresponding models and let users experience a wide variety of new environments. Existing algorithms generate landscapes immediately with view‐dependent resolution and without preprocessing. Unfortunately, landscapes generated by such algorithms lack river networks and therefore appear unnatural. Algorithms that integrate realistic river networks are computationally expensive and cannot be used to generate a locally adaptive high resolution landscape during a fly‐through. In this paper, we propose a novel algorithm to generate realistic river networks. Our procedural algorithm creates complete planets and landscapes with realistic river networks within seconds. It starts with a coarse base geometry of a planet without further preprocessing and user intervention. By exploiting current graphics hardware, the proposed algorithm is able to generate adaptively refined landscape geometry during fly‐throughs.     

Explaining employees' health care costs: A prospective examination of stressful job demands, personal control, and physiological reactivity.

The authors tested the ability of stressful demands and personal control in the workplace to predict employees' subsequent health care costs in a sample of 105 full-time nurses. Both subjective and objective measures of workload demands interacted with personal control perceptions in predicting the cumulative health care costs over the ensuing 5-year period. Tonic elevations in salivary cortisol, moreover, mediated the effects of demands and control on health care costs. Neither the job demands variables nor physiological reactivity measures, however, explained subsequent mental health. The results support findings from the epidemiological literature that demonstrate an important role for employees' control in explaining occupational inequalities in coronary heart disease and mortality. The authors argue that the results also encourage control-enhancing job design interventions by suggesting that their outcomes can benefit both organizations and their members. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Organization and occupation influences in the attraction–selection–attrition process.

This study tested predictions from B. Schneider's (1987) attraction–selection–attrition (ASA) model across 5 organizations (n?=?681). Organization membership and occupational attributes interacted with individuals' turnover intentions to predict several personality variables. Relationships among organization membership, occupation type, and personality were partially mediated by perceived structure. The 3-way interaction analyses indicated that occupation type may compensate for the effects of organizational characteristics in making particular traits more suitable for a given organization. The overall pattern of findings supports the more general ASA predictions, but the findings also suggest a need to develop a more refined conceptualization of the trait homogenization process. The authors also discuss what trait homogenization processes may imply about interpreting findings in organizational behavior research in general and better understanding organizational diversity, culture, and organizations' capabilities in responding to change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Positive affectivity and negative outcomes: the role of tenure and job satisfaction

In this study, the authors proposed and tested a 3-way interaction among positive affectivity (PA), job satisfaction, and tenure in predicting negative employee outcomes. Specifically, the authors predicted that the relationship between job satisfaction and negative outcomes would be stronger for high PAs and that this relationship would be more pronounced for longer tenured employees. Results support this 3-way interaction in predicting job search behavior, physical health complaints, and counterproductive employee behavior. In particular, the relationship between job satisfaction and negative outcomes was most strongly negative for high-PA individuals with longer tenure. The authors discuss the implications of these results and some directions for future research.     

Einsatz, Optimierung und Transportlogistik von Pumpsprengstoffen im Tunnel- und Kraftwerksbau — Beispiel Nassfeld

Through the optimization of the process chain supply and on-site production of emulsion explosives, tunnel construction is possible without the storage and the transport of explosives in large quantities. The coordinated interaction of humans and technology, which is described in this article on the basis of the construction site Nassfeld — building of pump-fed power stations, ensures the safe and efficient execution of the blasting work. Explosive quantities in the order of 170 tons per month, which are inconceivably to be handled with cartridged products, can be produced and pumped on-site.     

Barrier properties of poly(lactic acid)/cloisite 30B composites and their relation between oxygen permeability and relative humidity

Poly(lactic acid) based nanocomposite films were prepared by melt compounding and subsequent flat film extrusion. After characterizing the nanocomposites with the help of transmission electron microscopy and wide angle X‐ray diffraction to estimate the nanoclay distribution in the matrix material, the oxygen and water vapor permeability of untreated and annealed nanocomposite films were analyzed. A reduction to 34% of both permeability values could be realized by the addition of 6 wt % Cloisite 30B and subsequent annealing to realize maximum crystallinity. Experimental permeability as a function of nanoclay concentration was successfully described by the Tortuous Path Model. In addition, the correlation between oxygen permeability and relative humidity was analyzed for pure PLA and PLA based nanocomposite films. For both untreated films oxygen permeability decreased almost linearly between 0% and 96% RH to approximately 70% of the respective value for the dry sample. Annealed PLA films, on the other hand, showed a similar behavior up to 70% RH but an increase in oxygen permeation for higher moisture content. This is explained by the observed reduction in crystallinity generating more free volume, bringing the system closer to the amorphous case where permeability is generally higher. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44424.     

Chronic demands and responsivity to challenge

Certain kinds of arousal in response to challenge situations reflect conditioning that makes one adaptive to task demands. A growing literature implicates chronic stress as a factor degenerating this conditioning. This study investigated the relation between objective occupational demands to which workers were classified for at least 2 years and various indicators of adaptive responsivity to challenge situations. There were consistently significant and negative relations between the occupational exposures and cardiovascular and skin temperature responsivity to the acute challenges administered in the laboratory, the corresponding speed of recovery to baseline after removal of the challenge stimulus, and peripheral catecholamine changes during a work shift.     

Role of social support in the experience of stress at work.

It has been hypothesized that the positive relation between stress and strain responses is stronger for individuals who have low levels of social support than for those who have high levels of support. This hypothesis that social support buffers the negative effects of stress has been tested extensively in a variety of settings, with highly conflicting results. Some theorists have recently proposed that the moderating effect of social support is itself buffered by other variables such as sex or social class. The present study examined the role of social support in the experience of work stress with a sample large enough to provide statistically powerful tests of models of social support that specify 2- and 3-way interactions. Data were obtained from 326 employees (mean age 32.5 yrs). No support for higher order interactive models was found. In addition, no evidence emerged demonstrating any buffering effect for social support. Arguments are advanced for a parsimonious model in which social support has a modest direct effect of lowering experienced strain. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Monomer cast polyamide 6 composites and their treatment with high‐energy electrons

At first, the impact of selected spherically structured nanofillers made of different polar materials (carbon, silicon carbide, surface‐modified silica, 2 wt % each) on mechanical properties of monomer cast polyamide 6 (MCPA6) was examined. Only the low‐polar carbon‐based nanofiller showed an average particle size below 100 nm in the liquid phase before polymerization was initiated. With regard to neat MCPA6, mechanical properties of the composite loaded with the carbon nanoparticles like tensile strength, Young's modulus, and heat distortion temperature could be improved by 6.4%, 13.5%, and 27.5%, respectively. The efficiency of carbon as filler material for MCPA6 was also shown for carbon short‐cut fibers. A fiber content of 15% improved tensile strength from 78 to 93 MPa (19%) and Young's modulus could be doubled from 2660 MPa to nearly 5300 MPa. Regardless of the improved mechanical properties, the composites showed reduced degrees of crystallinity. Therefore, electron beam irradiation was applied to crosslink the polymer chains as an alternative to improve material properties. Crosslinking was supported by the application of a curing agent (CA). Two strategies for crosslinking experiments were tested: (1) Irradiation of CA‐containing neat MCPA6 to find the most effective dose and subsequent treatment of the composites under this special condition; (2) Optimization of the properties by irradiation of the composites itself at graduated dose values. The second way was more convenient and showed, with regard to the composites without CA, improvements of tensile strength and Young's modulus of 6% each. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011