Refine
Has Fulltext
- yes (77) (remove)
Year of publication
- 1994 (77) (remove)
Document Type
- Postprint (46)
- Article (17)
- Monograph/Edited Volume (8)
- Preprint (6)
Language
- German (52)
- English (23)
- Multiple languages (1)
- Slovak (1)
Keywords
- Anatomy (1)
- Animal (1)
- Biochemical analysis (1)
- Confluence (1)
- Experimental study (1)
- Exploration (1)
- Glucagon (1)
- Hepatic artery (1)
- Hepatocyte (rat) (1)
- Inflammation (1)
Institute
- Department Erziehungswissenschaft (21)
- Extern (17)
- Institut für Physik und Astronomie (8)
- Wirtschaftswissenschaften (8)
- Department Psychologie (6)
- Interdisziplinäres Zentrum für Dynamik komplexer Systeme (6)
- Institut für Ernährungswissenschaft (4)
- Institut für Germanistik (4)
- Institut für Mathematik (4)
- Institut für Umweltwissenschaften und Geographie (4)
Taking the visit of Erich Honecker to China as an example, the author analyses the bilateral GDR-Chinese relations in the 1980s. Based on extensive original research, the objectives as well as disappointed hopes are presented. The author reveals that not Honecker played the "Chinese Card", but he himself became part of Chinese politics. At the same time, the contradictory reaction to that visit in Moscow are documented when, with the election of Gorbachev, first signs of a change in Soviet policy toward China were indicated. Jahresabo: 40,00 € (ermäßigt: 25,00 €)
There has never been a theory of transition from really existing Socialism to a democratic and market-oriented system. Different theoretical approaches are taken into consideration by the author. Experiences of other transitional processes are practicable on Eastern Europe in a limited way. The missing of socio-structural differentiation, the socio-cultural consequences of the really existing Socialism and the international conditions did not promote the transition. It seems that the transition in Eastern Europe is obviously not a change from one political system to another one, but for the time being an open process.
A paradigm for the determination of time-accuracy functions (TAFs) for individual participants is introduced for two pairs of tasks differing in cognitive complexity, that is, word scanning vs cued recognition and figural scanning vs figural reasoning. TAFs can be used to test dissociations of cognitive processes beyond scale-related ambiguities of ordinal interactions. The approach is applied to examine the cognitive-aging hypothesis that a single slowing factor can account for interactions between adult age and cognitive task complexity. Twenty young and 20 old adults participated in 17 sessions. Presentation times required for 75, 87.5, and 100% accuracies were determined for each task with a variant of the psychophysical method of limits. Accuracy was fit by negatively accelerated functions of presentation time. State-trace analyses showed that different slowing factors are required for high- and low-complexity tasks. Relations to speed-accuracy and performance-resource functions are discussed.
Throughfall measurements were made under primary terra firme rainforest in the Rio Pichis valley, in the Upper Amazon Basin of Peru. Based on 214 precipitation events over nearly 18 months, throughfall was estimated to be 83.1±8.8% of gross precipitation. Regression analysis of all events revealed that gross precipitation is the only significant explanatory variable; the use of one-burst events does not significantly improve the regression relationship. Gross precipitation is, however, a poor predictor of throughfall for small rainfall events. The two forest structure parameters, canopy capacity, S, and free throughfall coefficient, p, were determined to be 1.3±0.2 mm and 0.32±0.18 mm. Rainfall intensity was found to influence these parameters. New methods which attempt to minimize the influence of meteorologic variables are used to estimate the potential values of these canopy parameters.
A Hamiltonian system in potential form (formula in the original abstract) subject to smooth constraints on q can be viewed as a Hamiltonian system on a manifold, but numerical computations must be performed in Rn. In this paper methods which reduce "Hamiltonian differential algebraic equations" to ODEs in Euclidean space are examined. The authors study the construction of canonical parameterizations or local charts as well as methods based on the construction of ODE systems in the space in which the constraint manifold is embedded which preserve the constraint manifold as an invariant manifold. In each case, a Hamiltonian system of ordinary differential equations is produced. The stability of the constraint invariants and the behavior of the original Hamiltonian along solutions are investigated both numerically and analytically.
Many methods have been proposed for the stabilization of higher index differential-algebraic equations (DAEs). Such methods often involve constraint differentiation and problem stabilization, thus obtaining a stabilized index reduction. A popular method is Baumgarte stabilization, but the choice of parameters to make it robust is unclear in practice. Here we explain why the Baumgarte method may run into trouble. We then show how to improve it. We further develop a unifying theory for stabilization methods which includes many of the various techniques proposed in the literature. Our approach is to (i) consider stabilization of ODEs with invariants, (ii) discretize the stabilizing term in a simple way, generally different from the ODE discretization, and (iii) use orthogonal projections whenever possible. The best methods thus obtained are related to methods of coordinate projection. We discuss them and make concrete algorithmic suggestions.
Many methods have been proposed for the simulation of constrained mechanical systems. The most obvious of these have mild instabilities and drift problems. Consequently, stabilization techniques have been proposed A popular stabilization method is Baumgarte's technique, but the choice of parameters to make it robust has been unclear in practice. Some of the simulation methods that have been proposed and used in computations are reviewed here, from a stability point of view. This involves concepts of differential-algebraic equation (DAE) and ordinary differential equation (ODE) invariants. An explanation of the difficulties that may be encountered using Baumgarte's method is given, and a discussion of why a further quest for better parameter values for this method will always remain frustrating is presented. It is then shown how Baumgarte's method can be improved. An efficient stabilization technique is proposed, which may employ explicit ODE solvers in case of nonstiff or highly oscillatory problems and which relates to coordinate projection methods. Examples of a two-link planar robotic arm and a squeezing mechanism illustrate the effectiveness of this new stabilization method.
Underlying the importance of revenue the author discusses the future of the international order from the perspective of political economy. The international system will not be a capitalist one. Political conflicts will not be removed by nonviolent market regulations. Weakness of labour force and a dominant role of revenue will further more result in political interventions by nation states. The struggle for revenue to maintain comparative advantages in high-tech-development strengthens state intervention in order to protect domestic market. The failure of the "development state" in the third world and the rising of fundamentalistic tendencies supported by a market-oriented middle class will increase conflicts in those regions.
Solubilization by polysoaps
(1994)
The aqueous solubilization power of several series of micellar homopolymers and copolymers (polysoaps) is investigated. Using five insoluble or poorly water-soluble dyes, comparisons of the capacities are made with respect ot the influence of structural variables such as the polymer backbone, the polymer geometry, the comonomer content, and the charge of the hydrophilic group. Some guidelines for polysoap structures suited for efficient solubilization are established. Noteworthy is that the solubilization capacities of the polysoaps are neither linked to the ability to reduce the surface tension of water, nor to the polarity of the solubilization sites deduced from spectroscopic probes.
Nasledujúci príspevok poslal časopisu Viera a život vedecký pracovník katolíckej teologickej fakulty na Regensburskej univerzite (Nemecko) pán Stefan Gatzhammer, M. A., Líc. iur. can. Podkladom pre článok bola rozpracovaná vedecká štúdia, preto aj nemecká pôvodina príspevku mala bohaté a dôkladné poznámky. S láskavým súhlasom autora sme pre potreby našich čitateľov poznámky zjednodušili. Pôvodný nemecký titul článku znie: „Die Ausweisung der Jesuiten aus Portugal 1759/60. Der Brasilienmissionar P. Josef Keyling SJ aus Schemnitz." Príspevok do slovenčiny preložila Zuzana Vaňová.
Sinnkrise des Wissens
(1994)
Dieser Aufsatz berichtet über die Ergebnisse einer umfassenden empirischen Untersuchung zur Schulsituation griechischer Kinder und Jugendlicher, die aus der BRD in ihre Heimat zurückgewandert sind. An Stichproben aus Grundschulen und Sekundarstufen wird überprüft, welche Probleme in den Schulleistungen und im psychosozialen Befinden bei Rückkehrern im Vergleich zu Einheimischen auftreten. Die Informationen über jeden Schüler enthalten mehrere Perspektiven: Lehrerurteil, Einschätzung durch die Mitschüler, Selbstkonzept sowie Schulleistungsindikatoren. Es zeigt sich, daß die Rückkehrerkinder schulisch im Rückstand liegen sowie eine Reihe psychosozialer Belastungen aufweisen, die je nach Remigrationszeitpunkt, Geschlecht etc. unterschiedlich ausgeprägt sind. Unproblematisch verläuft die Rückkehr in die Heimat und die schulische Integration nur, wenn sie vor dem 8. Lebensjahr erfolgt.
Two deterministic processes leading to roughening interfaces are considered. It is shown that the dynamics of linear perturbations of turbulent regimes in coupled map lattices is governed by a discrete version of the Kardar-Parisi-Zhang equation. The asymptotic scaling behavior of the perturbation field is investigated in the case of large lattices. Secondly, the dynamics of an order-disorder interface is modelled with a simple two-dimensional coupled map lattice, possesing a turbulent and a laminar state. It is demonstrated, that in some range of parameters the spreading of the turbulent state is accompanied by kinetic roughening of the interface.
In the modern industrialized countries every year several hundred thousands of people die due to the sudden cardiac death. The individual risk for this sudden cardiac death cannot be defined precisely by common available, non-invasive diagnostic tools like Holter-monitoring, highly amplified ECG and traditional linear analysis of heart rate variability (HRV). Therefore, we apply some rather unconventional methods of nonlinear dynamics to analyse the HRV. Especially, some complexity measures that are basing on symbolic dynamics as well as a new measure, the renormalized entropy, detect some abnormalities in the HRV of several patients who have been classified in the low risk group by traditional methods. A combination of these complexity measures with the parameters in the frequency domain seems to be a promising way to get a more precise definition of the individual risk. These findings have to be validated by a representative number of patients.
Contenuto: 1. Persone e situazioni: pietre angolari nella moderna psicologiadella personalità 2. La questione della costanza nella personalità: sessant'anni dicontroversia 3. In difesa dei tratti: nuove (e rinnovate) prospettive 4. II «moderno interazionismo»: una cornice alternativa alla ricercasulla personalità 5. Realizzare il programma interazionista: tre aree esemplaridi ricerca 6. Migliorare la misurazione della personalità: la via nomoteticaallo studio della costanza 7. La psicologia della personalità riguarda gli individui: la riscoperta dell'eredità idiografica 8. II ruolo della situazione nella ricerca sulla personalità 9. Psicologia della personalità negli anni Novanta: uno sguardo d'insieme
The site of confluence of the artery and the portal vein in the liver still appears to be controversial. Anatomical studies suggested a presinusoidal or an intrasinusoidal confluence in the first, second or even final third of the sinusoids. The objective of this investigation was to study the problem with functional biochemical techniques. Rat livers were perfused through the hepatic artery and simultaneously either in the orthograde direction from the portal vein to the hepatic vein or in the retrograde direction from the hepatic vein to the portal vein. Arterial how was linearly dependent on arterial pressure between 70 cm H2O and 120 cm H2O at a constant portal or hepatovenous pressure of 18 cm H2O. An arterial pressure of 100 cm H2O was required for the maintenance of a homogeneous orthograde perfusion of the whole parenchyma and of a physiologic ratio of arterial to portal how of about 1:3. Glucagon was infused either through the artery or the portal vein and hepatic vein, respectively, to a submaximally effective ''calculated'' sinusoidal concentration after mixing of 0.1 nmol/L. During orthograde perfusions, arterial and portal glucagon caused the same increases in glucose output. Yet during retrograde perfusions, hepatovenous glucagon elicited metabolic alterations equal to those in orthograde perfusions, whereas arterial glucagon effected changes strongly reduced to between 10% and 50%. Arterially infused trypan blue was distributed homogeneously in the parenchyma during orthograde perfusions, whereas it reached clearly smaller areas of parenchyma during retrograde perfusions. Finally, arterially applied acridine orange was taken up by all periportal hepatocytes in the proximal half of the acinus during orthograde perfusions but only by a much smaller portion of periportal cells in the proximal third of the acinus during retrograde perfusions. These findings suggest that in rat liver, the hepatic artery and the portal vein mix before and within the first third of the sinusoids, rather than in the middle or even last third.
A detailed theoretical investigation of the reflection of an atomic de Broglie wave at an evanescent wave mirror is presented. The classical and the semiclassical descriptions of the reflection process are reviewed, and a full wave-mechanical approach based on the analytical soution of the corresponding Schrödinger equation is presented. The phase shift at reflection is calculated exactly and interpreted in terms of instantaneous reflection of the atom at an effective mirror. Besides the semiclassical regime of reflection describable by the WKB method, a pure quantum regime of reflection is identified in the limit where the incident de Broglie wavelength is large compared to the evanescent wave decay length.
Dieter Wagner untersucht die Art und Weise, in der die Personalfunktion in der Unternehmensleitung vertreten ist. Diskutiert werden sowohl die Dezentralisation der Personalarbeit als non plus ultra des modernen Personalmanagements als auch die Bedeutung des strategischen Personalmanagements. Auf der Grundlage umfangreicher Untersuchungen über Arbeitsdirektoren bzw. Personalvorstände in mitbestimmten Unternehmungen werden die wichtigsten Handlungsgrundlagen und die Zusammenarbeit der Beteiligten an der Betriebs- und Unternehmensverfassung kritisch dargestellt. Darüber hinaus entwickelt der Autor konzeptionelle Perspektiven eines Human Resources Management durch die Unternehmensführung. Dieter Wagner spricht nicht nur personalpolitische Empfehlungen aus, sondern knüpft zugleich die Verbindung zu aktuellen Entwicklungstendenzen einer dezentralen Personalorganisation und zum internationalen Personalmanagement. „Personalfunktion in der Unternehmensleitung" richtet sich an Studenten und Wissenschaftler der Betriebswirtschaftslehre, insbesondere mit den Schwerpunkten Personalwesen, Organisation und Unternehmensführung. Für Führungskräfte aller Branchen und besonders für Personalvorstände und Personalleiter ist dieses Buch ein wertvolles Nachschlagewerk.
We have used techniques of nonlinear dynamics to compare a special model for the reversals of the Earth's magnetic field with the observational data. Although this model is rather simple, there is no essential difference to the data by means of well-known characteristics, such as correlation function and probability distribution. Applying methods of symbolic dynamics we have found that the considered model is not able to describe the dynamical properties of the observed process. These significant differences are expressed by algorithmic complexity and Renyi information.
We have studied bifurcation phenomena for the incompressable Navier-Stokes equations in two space dimensions with periodic boundary conditions. Fourier representations of velocity and pressure have been used to transform the original partial differential equations into systems of ordinary differential equations (ODE), to which then numerical methods for the qualitative analysis of systems of ODE have been applied, supplemented by the simulative calculation of solutions for selected initial conditions. Invariant sets, notably steady states, have been traced for varying Reynolds number or strength of the imposed forcing, respectively. A complete bifurcation sequence leading to chaos is described in detail, including the calculation of the Lyapunov exponents that characterize the resulting chaotic branch in the bifurcation diagram.
In this paper, we show that symplectic partitioned Runge-Kutta methods conserve momentum maps corresponding to linear symmetry groups acting on the phase space of Hamiltonian differential equations by extended point transformation. We also generalize this result to constrained systems and show how this conservation property relates to the symplectic integration of Lie-Poisson systems on certain submanifolds of the general matrix group GL(n).
Rat hepatocytes have previously been reported to possess prostaglandin E₂ receptors of the EP₃-type (EP₃-receptors) that inhibit glucagonstimulated glycogenolysis by decreasing cAMP. Here, the isolation of a functional EP₃ϐ receptor cDNA clone from a rat hepatocyte cDNA library is reported. This clone can be translated into a 362-amino-acid protein, that displays over 95% homology to the EP₃ϐ receptor from mouse mastocytoma. The amino- and carboxy-terminal region of the protein are least conserved. Transiently transfected HEK 293 cells expressed a single binding site for PGE₂ with an apparent Kd of 15 nM. PGE₂ > PGF₂α > PGD₂ competed for [³H]PGE₂ binding sites as did the EP₃ receptor agonists M&B 28767 = sulprostone > misoprostol but not the EP₁ receptor antagonist SC 19220. In stably transfected CHO cells M&B 28767 > sulprostone = PGE₂ > misoprostol > PGF₂α inhibited the forskolin-elicited cAMP formation. Thus, the characteristics of the EP₃ϐ receptor of rat hepatocytes closely resemble those of the EP₃ϐ receptor of mouse mastocytoma.
Inhalt: 1. CHARAKTER DER ANLAGE 2. AUFGABENSTELLUNG 3. ZIEL DER ARBEIT 4. ANTIKE QUELLEN 5. FORSCHUNGSGESCHICHTE 6. VERMESSUNG DER ANLAGE (Blatt 1) 7. BESTANDSAUFNAHME (Blatt 2) 8. GRABUNGSARBEITEN 8.1 Die Plana - schichtenweises Abtragen (Blätter 2, 3, 4) 8.2 Anlegen von Schnitten (Blätter 5, 6, 7) 8.3 Zeichnen der Profile (Blätter 8, 9, 10) 8.4 Beschreibung 9. ARCHITEKTURELEMENTE 9.1. Architrave (Blatt 11) 9.2. Säulenfragmente (Blatt 12) 9.3. Hohlkehlen, Steine mit dem Uräusschlangenmotiv und andere Architekturelemente (Blätter 11, 13, 14, 15) 9.4. Fundamentsteine ( Blatt 16) 10. SKULPTUREN (Blätter 17, 18, 19) 11. KLEINFUNDE (Blatt 20) 12. SONSTIGE FUNDE (Blätter 21, 22, 23) 13. KERAMIK 13.1. Vereinfachte Keramikbearbeitung (Blätter 24, 25) 13.2. Verfeinerte Methode der Keramikbearbeitung (Blatt 26) 13.3. Vollständige Keramikgefäße 14. FOTOARBEITEN 15. REKONSTRUKTION
Lernstrategien im Studium : Ergebnisse zur Faktorenstruktur und Reliabilität eines neuen Fragebogens
(1994)
Der vorliegende Beitrag berichtet über die Entwicklung eines Inventars zur Erfassung von Lernstrategien im Studium (LIST). Das Verfahren gliedert sich in drei Teilbereiche: (1) «Kognitive Strategien», (2) «Metakognitive Strategien» und (3) «Ressourcenbezogene Strategien». Jeder Teilbereich wird durch mehrere Einzelskalen abgebildet. Der Fragebogen wurde nach verschiedenen Pilotuntersuchungen an einer Stichprobe von 310 Studenten verschiedener Studiengänge eingesetzt. Die Ergebnisse zeigen eine gut interpretierbare Faktorenstruktur sowie zufriedenstellende Reliabilitätsindizes. Das Verfahren ist in erster Linie zur Anwendung bei Studenten vorgesehen, kann aber auch bei anderen erwachsenen Lernergruppen eingesetzt werden.
Lernstrategien
(1994)
Learning strategies
(1994)
Although without providing a systematical comparison, it has become clear that the sects or party-factions of Japan’s New Left movement are by no means merely copies of their counterparts in the West. On the other hand their conduct may not be judged as to be a unique Japanese phenomenon. What they embody is, on the whole, a complex symbiosis of universal and particularly Japanese features, which can be observed in the fields of social behavior, organizational structure, and group dynamics. The particularity of the New Left factions is mostly revealed through the higher intensity of specific features rather than through pecularities found only in Japan.
Die vorliegende Arbeit gibt einen Überblick zu Theorien der intrinsischen Lernmotivation (ILM) und berichtet von einer Metaanalyse empirischer Befunde zum Zusammenhang von ILM und Lernen anhand von vier Gruppen von Lernindikatoren: Noten, Leistungstests, spezifische Lernkriterien (z.B. Behalten eines spezifischen Textes) und Verwendung von Lernstrategien. Die Ergebnisse zeigen, daß ILM niedrige aber konsistent positive Korrelationen mit Noten und Tests aufweist, und daß ILM vor allem tiefergehende bzw. konzeptuelle Formen des Lernens begünstigt. Die Ausprägung extrinsischer Lernmotivation (ELM) erwies sich als schwacher und meist nicht signifikanter Prädiktor der Lernleistung. Wenn überhaupt, so scheint ELM oberflächliche Formen des Lernens zu fördern.
This study investigated the relation between interest in four different subject areas (mathematics, biology, English, history) and the quality of experience in class. The strength of interest as a predictor of experience was contrasted with that of achievement motivation and scholastic ability. A total of208 highly able freshmen and sophomores completed interest ratings, an achievement motivation questionnaire, and the Preliminary Scholastic Aptitude Test (PSAT). These assessments were followed by one week of experience sampling. In addition, grades were available for the subject areas involved. The results showed that interest was a significant predictor of the experience of potency, intrinsic motivation, self-esteem, and perception of skill. Controlling for ability and achievement motivation did not decrease the strength of these relations. Achievement motivation and ability proved to be considerably weaker predictors of the quality of experience than was interest. In addition, interest contributed significantly to the prediction of grades in mathematics, biology, and history, but not English. The main results and some limitations of the study are discussed, and suggestions for future research are made.
Content: Architecture of the liver acinus Functional zonation of the liver acinus Topological organization of metabollc regulation in the acinus Topological organization of defense and organ structure regulation in the acinus
In cultured rat hepatocytes the key gluconeogenic enzyme phosphoenolpyruvate carboxykinase (PCK) is known to be induced by glucagon via an elevation of cAMP. Prostaglandin E₂ has been shown to antagonize the glucagon-activated cAMP formation, glycogen phosphorylase activity and glucose output in hepatocytes. It was the purpose of the current investigation to study the potential of PGE₂ to inhibit the glucagon-induced expression of PCK on the level of mRNA and enzyme activity. PCK mRNA and enzyme activity were increased by 0.1 nM glucagon to a maximum after 2 h and 4 h, respectively. This increase was completely inhibited if 10 μM PGE2 was added concomitantly with glucagon. This inhibition by PGE₂ of glucagon-induced PCK activity was abolished by pertussis toxin treatment. When added at the maximum of PCK mRNA at 2 h, PGE₂ accelerated the decay of mRNA and reduced enzyme activity. This effect was not reversed by pertussis toxin treatment. Since in liver PGE₂ is derived from Kupffer cells, which play a key role in the local inflammatory response, the present data imply that during inflammation PGE₂ may reduce the hepatic gluconeogenic capacity via a Gᵢ-linked signal chain.
Earlier investigations at South Creek in northeastern Queensland established the importance of overland flow as a hydrologic pathway in this tropical rainforest environment. Since this pathway is ‘fast’, transmitting presumably ‘new’ water, its importance should be reflected in the stormflow chemistry of South Creek: the greater the volumentric contribution to the stormflow hydrograph, the more similarity between the chemical composition of streamwater and of overland flow is to be expected. Water samples were taken during two storm events in an ephemeral gully (gully A), an intermittent gully (gully B) and at the South Creek catchment outlet; additional spot checks were made in several poorly defined rills. The chemical composition of ‘old’ water was determined from 45 baseflow samples collected throughout February. The two events differed considerably in their magnitudes, intensities and antecedent moisture conditions. In both events, the stormflow chemistry in South Creek was characterized by a sharp decrease in Ca, Mg, Na, Si, Cl, EC, ANC, alkalinity and total inorganic carbon. pH remained nearly constant with discharge, whereas K increased sharply, as did sulfate in an ill-defined manner. In event 1, this South Creek stormflow pattern was closely matched by the pattern in gully A, implying a dominant contribution of ‘new’ water. This match was confirmed by the spot samples from rills. Gully B behaved like South Creek itself, but with a dampened ‘new’ water signal, indicating less overland flow generation in its subcatchment. In event 2, which occurred five days later, the initial ‘new’ water signal in gully A was rapidly overwhelmed by a different signal which is attributed to rapid drainage from a perched water table. This study shows that stormflow in this rainforest catchment consists predominantly of ‘new’ water which reaches the stream channel via ‘fast’ pathways. Where the ephemeral gullies delivering overland flow are incised deeply enough to intersect a perched water table, a delayed, ‘old’ water-like signal may be transmitted.
The prepaparation of amorphous, homogeneous blends of zwitterionic polymers and transition metal salts was investigated. Homogeneous miscibility was achieved in many cases up to equimolar amounts of salt, depending on the anion and cation chosen. Various analytical techniques point to a solid state solution of the inorganic ions in the polymer matrix.
Flight and expulsion are and will remain important international problems. The existence of refugees is a result of unsolved domestic tasks. Thus, effective solutions require comprehensive and long-term strategies. So far the efforts to reduce the causes of escape have not been sufficient. In the current refugee crises millions of people can survive only with the help of an efficient international system (for example the UNHCR) that guarantees humanitarian aid and protection. However, this system has turned out to be inadequate although the potential of preventive action is sufficient to reach a major progress in diminishing the refugee problem.