Natural rain forest fires in Eastern Borneo during the Pleistocene and Holocene

We thank B. Zentgraf for his basic and constructive ideas and his field support, R. Andi Abdoerrachman for logistic and technical support and E. Shimokawa, Kagoshima University, for providing a charcoal sample from Kutai National Park. We thank P. Becker-Heidmann, Isotope Dating Laboratory, University of Hamburg, for his immediate ¹⁴C-dating by Liquid Scintillation Counting, and Chr. Goedicke, Rathgen Research Laboratory, Staatliche Museen Preussischer Kulturbesitz Berlin, for immediate TL dating. M. A. Gill, C.S.I.R.O. Canberra, has critically reviewed this paper. This research was sponsored by the Volkswagen Foundation.     

Nicht reproduzierbar: Versuchsergebnisse zur synergistischen Wirkung von Xeno?strogenen

Ohne Zusammenfassung     

Conflict,justice, and inequality: Why perceptions of leader–member exchange differentiation hurt performance in teams

To better understand why leader–member exchange (LMX) differentiation in teams may be detrimental to individual and team performance, we propose that team members' perception of LMX differentiation (PLMXD) is more important than statistical measures of LMX differentiation. Specifically, we hypothesize a multilevel model in which relationship conflict and procedural justice (climate) mediate the relationships of individual and collective PLMXDs with individual and team performance, respectively. Using a sample of 235 individuals in 53 teams, we found that individual PLMXD was negatively related to individual performance through relationship conflict perceptions, controlling for LMX. At the team level, collective PLMXD was negatively related to team performance through procedural justice climate and relationship conflict, controlling for a statistical measure of LMXD. Theoretical implications and directions for future research are explored.     

Understanding organizational embeddedness and career success: Who and what you know

Integrating job embeddedness theory with the sponsored and contest mobility perspectives, we developed and tested a model linking organizational embeddedness with two indicators of career success within the organization (promotion and career satisfaction), via the mediating roles of employees' organizational sponsorship network and job-related human capital development. Data from 188 employees and their supervisors over a 1-year period showed that, after controlling for employees' initial levels of career satisfaction and job performance, only job-related human capital development transmitted the positive effects of organizational embeddedness on promotion and career satisfaction. Supplemental analyses revealed that organizational sponsorship network's positive effects on promotion and career satisfaction were transmitted indirectly, via job-related human capital development. Our findings illustrate the importance of integrating sponsored and contest mobility perspectives and contribute to research on organizational embeddedness by extending its outcomes to include career success within the organization and specifying the process through which organizational embeddedness is related to career success within the organization.     

Analysis of radon origin by backward atmospheric transport modelling

This work shows how ambient radon concentrations measured at Cabauw station in central Netherlands are influenced by transport from different regions under typical transport conditions occurring during April and November, 2007 by means of atmospheric Lagrangian particle dispersion modelling in a receptor-oriented approach. Four specific regions have been isolated to assess their contribution to the modelled radon ambient concentrations at Cabauw, and two different radon flux assumptions. Westerly flows coming from the ocean are poor in radon and do not increase radon air concentrations unless there is some fetch over the British Isles. Continental transport, mainly from eastern and southern Europe, significantly increases radon background concentrations, reaching increments of 3 Bq m^?3. A constant 0.66 atoms cm^?2 s^?1 radon flux over land and zero over water bodies is a good approximation for the source term in order to study regional contributions and modulation of the radon background.     

Störungen der Entwicklung und Funktion des männlichen Reproduktionssystems

Various recently published studies indicate increases in disorders of development and function of the male reproductive system during the last decades. This refers to reports on a decline in sperm count and increased incidences of testicular cancer, cryptorchidism and hypospadias. While the results of studies on the increase in (geographically varying) incidences of testicular cancer are unequivocal, data on changes in rates of cryptorchidism and hypospadias are rather limited. Meanwhile, numerous retrospective studies on changes in sperm concentrations in the ejaculate of normal men have been published. However, at present it is not possible to draw generally valid conclusions since results from some countries or geographic regions indicate a significant decline while in others either no changes or even slight increases have been reported. According to the so-called “Estrogen hypothesis”, the common cause of these disorders shall be an increased prenatal exposure to estrogens. Concerning exogenous estrogens, synthetic estrogens, phyto and mycoestrogens, and chemicals with estrogenic activity could play a role. A search in the available literature has revealed that at present more than 100 chemical compounds from different classes are known to possess estrogenic activity. This, however, is not the only way in which chemicals may be endocrinically active. Ubiquitously distributed compounds from the classes of polychlorinated dibenzodioxins/furans and biphenyls exhibit an antiestrogenic potential, while chemicals like p,p′-DDE, Linuron and Vinclozolin being competitive androgen receptor antagonists may act as antiandrogens. Concerning the very limited current knowledge, the estrogen hypothesis at present only represents an interesting basis for discussion. Most questions that would have to be answered in order to accept, reject or modify tis hypothesis are either completely open or only partially understood. Thus, there is an urgent need to initiate research efforts to clarify the toxicological significance for ecosystems and humans of chemicals with endocrine activity.     

Evaluation of land use and water quality in an agricultural watershed in the USA indicates multiple sources of bacterial impairment

Pathogens are the number one cause of impairments of assessed rivers and streams in the USA and pose a significant human health hazard. The Dry Run Creek Watershed in Northeast Iowa has been designated as impaired by the State of Iowa because of high levels of Escherichia coli bacteria. To investigate the nature of this impairment, land use and stream bank assessments were coupled with comprehensive water quality monitoring. Physical, chemical, and biological parameters were measured at 13 different sites in the watershed, including pH, temperature, conductivity, dissolved oxygen, turbidity, total Kjeldahl nitrogen, ammonia-N, nitrate?+?nitrite-N, total phosphorus, and E. coli. In addition, benthic macroinvertebrate communities were analyzed at seven sites, and optical brightener tests were performed late in the season. Results identified segments of the watershed that were more prominent contributors of E. coli, and correlations were observed between levels of E. coli and several chemical parameters, including ammonia-N, total Kjeldahl nitrogen, and total phosphorus. Interestingly, distinct sites emerged as more prominent contributors of these elements during rain vs. non-rain events, suggesting different types of sources. Both the amount of rainfall and the time elapsed between the rain event and the sampling influenced E. coli levels during wet weather conditions. Nitrate?+?nitrite-N displayed a unique response to rain events compared with the other parameters, suggesting a different delivery route. Analyses of benthic macroinvertebrate communities were consistent with pollution trends. Collectively, these data suggest distinct agriculturally related E. coli contributions, as well as specific areas and practices for water quality improvement strategies. This study can serve as a resource for evaluating agricultural watersheds that are impaired for bacteria.