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181.
Meeting lateness is pervasive and potentially highly consequential for individuals, groups, and organizations. In Study 1, we first examined base rates of lateness to meetings in an employee sample and found that meeting lateness is negatively related to both meeting satisfaction and effectiveness. We then conducted 2 lab studies to better understand the nature of this negative relationship between meeting lateness and meeting outcomes. In Study 2, we manipulated meeting lateness using a confederate and showed that participants' anticipated meeting satisfaction and effectiveness were significantly lower when meetings started late. In Study 3, participants holding actual group meetings were randomly and blindly assigned to either a 10 min late, 5 min late, or a control condition (n = 16 groups in each condition). We found significant differences concerning participants' perceived meeting satisfaction and meeting effectiveness, as well as objective group performance outcomes (number, quality, and feasibility of ideas produced in the meeting). We also identified differences in negative socioemotional group interaction behaviors depending on meeting lateness. In concert, our findings establish meeting lateness as an important organizational phenomenon and provide important conceptual and empirical implications for meeting research and practice. 相似文献
182.
Winfried Schröder Cordula Englert Roland Pesch Harald G. Zechmeister Lotti Thöni Ivan Suchara Blanka Maňkovská Zvonka Jeran Harry Harmens Krystyna Grodzinska Renate Alber 《Environmental Sciences Europe》2008,20(2):120-132
Goal and Scope
Several studies show that the concentration of metals in mosses depends not only on metal deposition but also on factors such as moss species, canopy drip, precipitation, altitude, distance to the sea and the analytical technique used. However, contrasting results have been reported and the interpretation of the spatial variability of the metal accumulation in mosses remains difficult. In the presented study existing monitoring data from the European Heavy Metals in Mosses Surveys together with surface data on precipitation, elevation and land use are statistically analysed to assess factors other than emissions that have an influence on the metal accumulation in the mosses.Main Features
Inference statistics and Spearman correlation analysis were applied to examine the association of the metal accumulation and the distance of the monitoring sites to the sea as well as the altitude. Whether or not significant differences of the metal loads in the mosses exist at national borders was examined with help of the U-test after Mann and Whitney. In order to identify and rank the factors that are assumed to have an influence on the metal uptake of the mosses Classification and Regression Trees (CART) were applied.Results
No clear tendency could be derived from the results of the inference statistical calculations and the correlation analyses with regard to the distance of the monitoring site to the sea and the altitude. According to the results of the CART-analyses mainly the moss species, potential emission sources around the monitoring sites, canopy drip and precipitation have an effect on the metal bioaccumulation. Assuming that each participating country followed strictly the manual for sampling and sample preparation the results of the inference statistical calculations furthermore suggest that in most cases different techniques for digestion and analysis bias the measurements significantly.Discussion
For the first time a national monitoring data base consisting of measurement data and metadata as well as surface information on precipitation, land use and elevation was applied to examine influence factors on the metal bioaccumulation in mosses. The respective results mirror existing knowledge from other national studies to a large extend, although further analyses are necessary to affirm the findings. These analyses should include data from other national monitoring programmes and should additionally be carried out with other decision tree algorithms than CART.Conclusions
The local variability in the metal concentration in mosses can be uncovered in terms of predictors or underlying hidden causes by using CART. Ideally, such an approach should be applied across the whole of Europe. This will only be feasible if all participating countries provide additional information about site characteristics as currently is done in for example the German moss surveys.Recommendations
The UNECE Metals in Mosses Survey experimental protocol should be improved in order to reduce the observed influences, to enhance standardisation, and to strengthen the quality control. This implies the integration of sampling site describing metadata into the assessment. Furthermore, basis research is needed to test the hypothesis concerning moss species-specific accumulation of depositions.Perspectives
Provided that the presented results hold true in further analyses correction factors should be applied on the moss data in order to get the depicted spatial patterns and temporal trends of metal bioaccumulation unbiased. Such factors should be calculated for natural landscape units or ecoregions that are homogeneous with regard to climate, vegetation and altitude. 相似文献183.
Experiments were carried out in order to obtain information on the uptake characteristics of metals in the algal and fungal components of lichens. The uptake of 115Cd, 65Zn, 64Cu, 140La, 187W and 76As in the alga Scenedesmus pannonicus, subsp. Berlin and the fungus Aureobasidium pullulans was determined at pH 7 and 5 respectively, in 4 h experiments varying with respect to temperature and Ca2+ solution concentrations. Furthermore, the effects of pre-rinsing the cell suspensions on metal uptake were investigated.Pre-rinsing resulted in decreased uptake of W and As by algae and in increased uptake of all elements measured by fungi, which may be attributed to combined effects of starvation and changing densities.For algae, the uptake rates of As, W, Zn and Cd were markedly increased at the highest temperature employed. For Cu and La hardly any effects of temperature were observed, indicating the absence of metabolically controlled uptake. For fungi, but for As no relation of uptake with temperature could be determined.The presence of Ca2+ ions in the solution applied hardly affected the uptake of As but resulted in increased uptake of W by both the algae and the fungi. The effects of Ca2+ on the uptake of Cu and La were relatively small, probably due to specific binding sites in the cell walls for Cu and to the supercalcium status of the La-ion.The presence of Ca2+ caused decreased uptake of Cd2+ and Zn2+ by algae, but hardly affected the uptake of Zn2+ by fungi.The results indicate component-specific uptake and accumulation behaviour in intact lichens. 相似文献
184.
Otto Lüderitz Chris Galanos Volker Lehmann Hubert Mayer Ernst Th. Rietschel Jürgen Weckesser 《Die Naturwissenschaften》1978,65(11):578-585
The endotoxic principle of lipopolysaccharides (LPS) is localized in their lipid A component. Biological effects of LPS on, for instance, body temperature, blood pressure, and blood picture, are also induced by free lipid A. In contrast to the great variability of the 0-specific chains, the chemical structure of lipid A is much more constant. It is common for Salmonella and similar for other genera of the Enterobacteriaceae. Recently, a number of lipid A's have been recognized that exhibited distinct structural features compared with Enterobacteriaceae. These lipid A's were found to be also distinct with regard to some of their biological properties. 相似文献
185.
C. Sch?fers T. Frische H.-C. Stolzenberg A. Weyers S. Zok und Th. Knacker 《Umweltwissenschaften und Schadstoff-Forschung》2008,20(3):229-233
Ohne Zusammenfassung Hintergrundinformation Umweltbundesamt (2007). Abschlussbericht des Forschungsprojektes „Charakterisierung endokrin vermittelter Wirkungen in Fischen: Relevante Parameter für die Entwicklung einer neuen OECD-Testmethode und in der Anwendung in der gesetzlichen Umweltrisikobewertung“ im Auftrag des Umweltbundesamtes (F?rderkennzeichen 206 67 470). Online erh?ltlich unter 相似文献
186.
187.
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189.
F. L. Boschke E. Lamla W. Jost H. Elsässer H. Haffner W. Funke R. Tschesche S. Hünig Th. Wieland O. Prokop P. Läuger G. Pfleiderer E. Macher G. Drews G. Siebert H. W. Raudonat H. Autrum H. Sioli B. Frenzel K. Esser D. H. Welte H. -U. Schmincke K. Strobach M. Schidlowski 《Die Naturwissenschaften》1970,57(8):400-404
190.