TY - GEN A1 - Reich, Sebastian T1 - On an existence and uniqueness theory for nonlinear differential-algebraic equations N2 - An existence and uniqueness theory is developed for general nonlinear and nonautonomous differential-algebraic equations (DAEs) by exploiting their underlying differential-geometric structure. A DAE is called regular if there is a unique nonautonomous vector field such that the solutions of the DAE and the solutions of the vector field are in one-to-one correspondence. Sufficient conditions for regularity of a DAE are derived in terms of constrained manifolds. Based on this differential-geometric characterization, existence and uniqueness results are stated for regular DAEs. Furthermore, our not ons are compared with techniques frequently used in the literature such as index and solvability. The results are illustrated in detail by means of a simple circuit example. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 158 Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-46706 ER - TY - GEN A1 - Muschol, Waldemar A1 - Püschel, Gerhard Paul A1 - Hülsmann, Martina A1 - Jungermann, Kurt T1 - Eicosanoid-mediated increase in glucose and lactate output as well as decrease and redistribution of flow by complement-activated rat serum in perfused rat liver N2 - Rat serum, in which the complement sytem had been activated by incubation with zymosan, increased the glucose and lactate output, and reduced and redistributed the flow in isolated perfused rat liver clearly more than the control serum. Heat inactivation of the rat serum prior to zymosan incubation abolished this difference. Metabolic and hemodynamic alterations caused by the activated serum were dose dependent. They were almost completely inhibited by the cyclooxygenase inhibitor indomethacin and by the thromboxane antagonist 4-[2-(4-chlorobenzenesulfonamide)-ethyl]-benzene-acetica cid (BM 13505), but clearly less efficiently by the 5’-lipoxygenase inhibitor nordihydroguaiaretic acid and the leukotriene antagonist N-{3-[3-(4-acetyl-3-hydroxy-2-propyl-phenoxy)-propoxy]-4-chlorine-6-methyl-phenyl}-1H-tetrazole-5-carboxamide sodium salt (CGP 35949 B). Control serum and to a much larger extent complement-activated serum, caused an overflow of thromboxane B₂ and prostaglandin F₂α into the hepatic vein. It is concluded that the activated complement system of rat serum can influence liver metabolism and hemodynamics via release from nonparenchymal liver cells of thromboxane and prostaglandins, the latter of which can in turn act on the parenchymal cells. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - pape 116 Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-45892 ER - TY - GEN A1 - Dittmann-Kohli, Freya A1 - Lachmann, Margie E. A1 - Kliegl, Reinhold A1 - Baltes, Paul B. T1 - Effects of cognitive training and testing on intellectual efficacy beliefs in elderly adults N2 - Elderly adults (N = 116; average age = 73 years) were randomly assigned to one of four treatment groups varying in the amount of training and testing on fluid intelligence tests. They were compared before and after treatment on self-efficacy and utility beliefs for intelligence tests and everyday competence. Although both ability training and extended retest practice resulted in significant gains in objective test performance (Baltes, Kliegl, & Dittmann-Kohli, 1988), only ability training resulted in positive changes in self-efficacy. However, these changes were restricted to testrelated self-efficacy. Training had no impact on perceived utility or on everyday self-efficacy beliefs. Implications of the results are discussed with regard to interventions to increase intellectual self-efficacy in elderly persons. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 157 Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-40351 ER - TY - GEN A1 - Thompson, Laura A. A1 - Kliegl, Reinhold T1 - Adult age effects of plausibility on memory : the role of time constraints during encoding N2 - We investigated the role of training-induced knowledge Schemas and encoding time on adult age differences in recall. High-plausible (schema coherent) words were recalled better than lowplausible (schema discrepant) words in both age groups. This difference was larger for old-adults than for young adults for presentation times ranging from 3 s to 11 s per word. After equating participants in overall recall (i.e., at 50% correct) by dynamic adjustment of presentation time, old adults again showed a stronger plausibility effect than young adults when recall was above criterion. In a second experiment with self-paced encoding, old adults used more time than young adults only for low-plausible pairs, yet they still remembered fewer of them. In a third experiment, both age groups preferred to imagine high- rather than low-plausible words, but this effect was more pronounced in old adults. The results indicate that, compared with young adults, old adults find it particularly difficult to form elaborative mental images of schema-discrepant information under a wide variety of time constraints during encoding. Results are discussed in relation to explanations based on age-related mental slowing. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 156 Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-40347 ER - TY - GEN A1 - Krahé, Barbara T1 - Police officers' definitions of rape : a prototype study N2 - The study investigates police officers' definitions of different rape situations. On the basis of the concept of 'cognitive prototypes' a methodology is developed which elicits consensual feature lists describing six rape situations: the typical, i.e. most common rape, the credible, dubious, and false rape complaints as weil as the rape experiences that are particularly hard vs. relatively easy for the victim to cope with. Qualitative analysis of the data allows the identification of the characteristic features defining the prototype of each rape situation, as weil as comparisons between the situations in terms of their common and distinctive features. It is shown that police officers, while sharing some of the widely held stereotypes about rape, generally perceive rape as a serious crime with long-term negative consequences for the victim. The quantitative analysis of prototype similarity between the six situations corroborates this conclusion by demonstrating a high similarity between the prototypes of the typical and the credible rape situation: In addition, subjects' general attitude towards rape victims is measured to compare the prototypes provided by respondents holding a positive vs. negative attitude towards rape victims. Findings for the two groups, however, reveal more similarities than differences in their descriptions of rape prototypes. The paper concludes with a discussion of the feasibility of the prototype approach presented in this study as a strategy for investigating implicit or common-sense theories of rape. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 074 Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-33922 ER - TY - GEN A1 - Krahé, Barbara T1 - Social psychological issues in the study of rape N2 - The chapter presents a social psychological approach to the study of rape and sexual assault. Two issues are at the core of this approach: identifying the critical variables that affect attributions of responsibility to victims of rape. and exploring people's subjective definitions of rape, which may differ markedly from legal definitions. Following a review of the American evidence, a series of studies conductcd in two European countries is presented to address these issues. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 073 Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-33903 ER - TY - GEN A1 - Schiefele, Ulrich T1 - Interest, learning, and motivation N2 - Recent research related to the concept of interest is reviewed. It is argued that current constructs of motivation fail to include crucial aspects of the meaning of interest emphasized by classical American and German educational theorists. In contrast with many contemporary concepts (e.g., intrinsic learning orientation), interest is defined as a content-specific motivational characteristic composed of intrinsic feeling-related and value-related valences. Results from a number of studies are presented that indicate the importance of interest for the depth of text comprehension, the use of learning strategies, and the quality of the emotional experience while learning. The implications of these results and possible directions for future research are discussed. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 053 Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-33536 ER - TY - GEN A1 - Anton, Peter A1 - Laschewsky, André T1 - Polysoaps via alternating olefin/SO2 copolymers N2 - Contents: Introduction Results and discussion - Monomers studied - Monomer properties - Polymerization, copolymer composition and general properties - Polymer properties in aqueous solution Conclusion Experimental part - Materials - Copolymerization with S02 (typical procedure) - Methods T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 088 Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17216 ER - TY - GEN A1 - Bubeck, Christoph A1 - Laschewsky, André A1 - Lupo, Donald A1 - Neher, Dieter A1 - Ottenbreit, Petra A1 - Paulus, Wolfgang A1 - Prass, Werner A1 - Ringsdorf, Helmut A1 - Wegner, Gerhard T1 - Amphiphilic dyes for nonlinear optics: Dependence of second harmonic generation on functional group substitution T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 082 Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17201 ER - TY - GEN A1 - Embs, Frank A1 - Funhoff, Dirk A1 - Laschewsky, André A1 - Licht, Ulrike A1 - Ohst, Holger A1 - Prass, Werner A1 - Ringsdorf, Helmut A1 - Wegner, Gerhard A1 - Wehrmann, Rolf T1 - Preformed polymers for Langmuir-Blodgett films- molecular concepts N2 - The use of preformed polymers for the preparation of Langmuir-Blodgett (LB) multilayers is reviewed. Principles for polymer self-organization are outlined and the appropriate molecular designs are discussed. Recent developments in the different classes of polymers for LB multilayers are presented, and their outstanding properties highlighted. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 081 KW - Amphiphilic Polymers KW - Rod-like Polymers KW - LCPs KW - Stability of LB Films Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17196 ER - TY - GEN A1 - Laschewsky, André T1 - Oligoethyleneoxide spacer groups in polymerizable surfactants N2 - Cationic and zwitterionic polymerizable surfactants bearing tri- and tetraethyleneglycol spacer groups between the polymerizable moiety and the surfactant structure were prepared and polymerized. Monomers and polymers were investigated with respect to their aggregation behavior in aqueous systems and compared to analogous monomers and polymers lacking spacer groups. In the case of the monomeric surfactants, the spacer groups depress both the Kraffttemperature and the critical micelle concentration. the area occupied per molecule at the air-water interface is substantially enlarged by the spacers, whereas the depression of surface tension is nearly constant. Although the monomers with and without spacers are true surfactants, all the polymers are water-insoluble, but form monomolecular layers at the air-water interface. In analogy to the monomer behavior, the incorporation of the spacer groups increases the area occupied per repeat unit at the air-water interface substantially, but hardly affects the surface activity. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 059 KW - Polymerizable surfactant KW - polysoap KW - sulfobetain KW - spacer KW - micelle KW - monolayer Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17221 ER - TY - GEN A1 - Püschel, Gerhard Paul A1 - Oppermann, Martin A1 - Neuschäfer-Rube, Frank A1 - Götze, Otto A1 - Jungermann, Kurt T1 - Differential effects of human anaphylatoxin C3a on glucose output and flow in rat liver during orthograde and retrograde perfusion : the periportal scavenger cell hypothesis N2 - 1) During orthograde perfusion of rat liver human anaphylatoxin C3a caused an increase in glucose and lactate output and reduction of flow. These effects could be enhanced nearly twofold by co-infusion of the carboxypeptidase inhibitor MERGETPA, which reduced inactivation of C3a to C3adesArg. 2) During retrograde perfusion C3a caused a two- to threefold larger increase in glucose and lactate output and reduction of flow than in orthograde perfusions. These actions tended to be slightly enhanced by MERGETPA. 3) The elimination of C3a plus C3adesArg immunoreactivity during a single liver passage was around 67%, irrespective of the perfusion direction and the presence of the carboxypeptidase inhibitor MERGETPA; however, less C3adesArg and more intact C3a appeared in the perfusate in the presence of MERGETPA in orthograde and retrogade perfusions It is concluded that rat liver inactivated human anaphylatoxin C3a by conversion to C3adesArg and moreover eliminated it by an additional process. The inactivation to C3adesArg seemed to be located predominantly in the proximal periportal region of the liver sinusoid, since C3a was less effective in orthograde perfusions, when C3a first passed the proximal periportal region before reaching the predominant mass of parenchyma as its site of action, than in retrograde perfusions, when it first passed the perivenous area. These data may be evidence for a periportal scavenger mechanism, by which the liver protects itself from systemically released mediators of inflammation that interfere with the local regulation of liver metabolism and hemodynamics. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 040 Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-16747 ER -