Showing papers by "University of Bonn published in 1987"
1,525 citations
TL;DR: In this article, the authors analyzed the structure of credit market equilibrium under imperfect information and compared credit rationing and Collateralization as alternative means to cope with problems of adverse selection and moral hazard.
563 citations
456 citations
TL;DR: In this paper, the effects of chronic illness on marital relationships and the spouses' emotional and physical health were examined in chronic pain patients, their spouses, and a control sample of spouses of diabetic patients.
230 citations
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TL;DR: In this paper, it is argued that stability does not fully capture the logic of forward induction and that a large part of non-cooperative game theory may have to be modified in an essential way if one accepts stable equilibrium as the solution concept.
Abstract: This paper is an attempt to throw some light on the issues of whether requiring an equilibrium to be stable (in the sense of Kohlberg and Mertens) is necessary for self-enforcingness and what the implications of such a requirement are. In the first part it is discussed which role “mistakes” play in the stability concept and it is argued that stability does not fully capture the logic of forward induction. The second half is devoted to specific examples that show the power of stability and that indicate that a large part of noncooperative game theory may have to be modified in an essential way if one accepts stable equilibrium as the solution concept.
225 citations
223 citations
219 citations
TL;DR: It is demonstrated that the activity of the amidase is modulated by basic peptides in vitro and help to explain how Pep 5 and nisin may cause lysis of treated cells.
Abstract: Pep 5 and nisin are cationic peptide antibiotics which in addition to their membrane-disruptive action induce autolysis in staphylococci. To investigate the mechanism of lysis induction, the influence of the peptides on the activity of the N-acetylmuramoyl-L-alanine amidase of Staphylococcus simulans 22 was studied. In experiments with isolated cell walls at low ionic strength, the amidase activity was stimulated by the addition of Pep 5 and nisin, as well as by polylysine, streptomycin, and mono- and divalent cations. The concentrations necessary for activation depended on the nature of the cation and ranged from 5 microM for poly-L-lysine (n = 17) to 150 mM for Na+ at a cell wall concentration of 100 micrograms of cell walls per ml. No effect was observed if the cell walls were devoid of polyanionic constituents. Kinetic data suggested that the amidase bound to the teichoic and teichuronic acids of the cell wall and was thereby inhibited. Cationic molecules reversed this inhibition, most likely by displacing the enzyme from the polyanions. If the concentrations of the larger peptides were high in relation to cell wall concentration, the activation turned into inhibition, presumably by interfering with the access of the enzyme to its substrate. These experiments demonstrate that the activity of the amidase is modulated by basic peptides in vitro and help to explain how Pep 5 and nisin may cause lysis of treated cells.
192 citations
TL;DR: The peptide antibiotic nisin is shown to disrupt valinomycin-induced potassium diffusion potentials imposed on intact cells of Staphylococcus cohnii 22 suggesting that nisin has to be regarded as a membrane-depolarizing agent which acts in a voltage-dependent fashion.
Abstract: The peptide antibiotic nisin is shown to disrupt valinomycin-induced potassium diffusion potentials imposed on intact cells of Staphylococcus cohnii 22. Membrane depolarization occurred rapidly at high diffusion potentials while at low potentials nisin-induced depolarization was slower suggesting that nisin requires a membrane potential for activity. This assumption was proven in experiments with planar lipid bilayers (black lipid membranes). Macroscopic conductivity measurements indicated a voltage-dependent action of nisin. The potential must have a trans-negative orientation with respect to the addition of nisin (added to the cis-side) and a sufficient magnitude (ca. -100 mV). With intact cells the threshold potential was lower (-50 to -80 mV at pH 7.5 and below -50 mV at pH 5.5). Single channel recordings resolved transient multistate pores, strongly resembling those introduced by melittin into artificial bilayers. The pores had diameters in the range of 0.2–1 nm, and lifetimes of few to several hundred milliseconds. The results indicate that nisin has to be regarded as a membrane-depolarizing agent which acts in a voltage-dependent fashion.
183 citations
TL;DR: While only EEG provided specific diagnostic information, the focus definition was consistently good on PET images, poor on CT scans, and generally good but less consistent on MRI.
Abstract: Ten patients suffering from drug-resistant complex partial seizures, with EEG abnormalities in the temporal region, were studied by means of non-invasive electrophysiological techniques (video-monitored, 16-channel, prolonged surface and sphenoidal EEG) as well as by imaging techniques (CT, MRI, SPECT and PET). Analysis of interictal and ictal EEG indicated the localization of epileptic activity in one side in eight cases. CT demonstrated focal abnormalities in three, SPECT in five unequivocally (in another four questionably, with the same lateralization as indicated by PET), MRI in eight, and PET in all cases. While only EEG provided specific diagnostic information, the focus definition was consistently good on PET images, poor on CT scans, and generally good but less consistent on MRI.
167 citations
TL;DR: In this paper, the impact of public sector transfer payments on tax evasion behavior was investigated, and the influence of these variables on both the propensity to evade taxes and the extent of taxes evaded were investigated.
TL;DR: In this paper, the frequencies of a series of rotational transitions between 0.3 and 6 THz for several stable and readily obtainable gases (CO, HCl, and HF) were measured to an accuracy better than one part in 107.
TL;DR: Using [Cp(Me)5Rh(bipy)C1]C1 (1) as redox catalyst for the continous NADH regeneration, it was possible to perform an electrochemically driven enzymatic reduction of pyruvate to D-lactate catalyzed by D-LDH at a rate of 5 turnovers per hour as discussed by the authors.
TL;DR: In this article, storm-associated changes in the neutral gas composition may extend well beyond the region of auroral heating and these changes cannot be interpreted as a temperature effect, and it is concluded that negative ionospheric storms at middle latitudes are well explained by the observed composition changes and that the numerical modeling of thermospheric storm effects in this region requires further study.
TL;DR: It appears that acute muscle injury occurring upon onset of voluntary running is a usual event in the adaptation of muscles to altered use.
Abstract: Soleus, extensor digitorum longus and tibialis anterior muscles of mice voluntarily running in wheels for periods of 5 to 120 days were studied in spaced serial and serial cross-sections. Shortly after the onset of running and during the next 2 weeks, degeneration, necrosis, phagocytosis and regeneration of muscle fibers, satellite cell proliferation and cellular infiltration were found in soleus muscles of mice from all strains investigated (CBA/J, NMRI, C57b, NIH, SWS and Balb/c). Tibialis anterior but not extensor digitorum longus muscles were also damaged. Predominantly high-oxidative fibers were affected (both slow-oxidative and fast oxidative glycolytic in soleus, fast-oxidative glycolytic in tibialis anterior). Denervated soleus muscles that had been passively stretched during running were not damaged. Evidence was found that, during the early period of running, split fibers form by myogenesis within (regeneration) or outside (satellite cell proliferation) necrotic muscle fiber segments. Split fibers persisted in solei of long-term (2 to 3 months) exercised CBA/J but not NMRI mice. In 6 out of 20 solei of CBA/J runners exercised for 2 months or longer, fiber-type grouping was observed in the areas where extensive damage usually occurred in the early periods. The results show that different muscles are damaged and repaired to varying degrees and that marked interstrain and inter-individual differences are present. It appears that acute muscle injury occurring upon onset of voluntary running is a usual event in the adaptation of muscles to altered use.
TL;DR: The phospholipase C activity towards phosph atidylcholine and phosphatidylglycerol and acid sphingomyelinase activity copurified during the entire purification procedure, indicating that acid spongyelinase has phospholIPase CActivity towards these lipids.
TL;DR: Reduced clearance of trazodone among elderly men may indicate a need for dosage reduction during chronic therapy, and choice of dosage during chronic treatment should be based on ideal rather than total body weight.
Abstract: Single 25 mg intravenous and 50 mg oral doses of trazodone were given to 43 healthy subjects, divided into young men and women (aged 18 to 40 years) and elderly men and women (aged 60 to 76 years). Among men, trazodone volume of distribution (Varea) was increased in elderly vs. young subjects (1.15 vs. 0.89 L/kg; P less than 0.05), and clearance decreased (1.65 vs. 2.31 ml/min/kg; P less than 0.05), thereby increasing elimination half-life (t1/2) in elderly men (8.2 vs. 4.7 hours; P less than 0.001). Varea in women was also increased in the elderly (1.5 vs. 1.27 L/kg; P less than 0.02), causing increased t1/2 (7.6 vs. 5.9 hours; P less than 0.05), but clearance was unrelated to age. Absolute bioavailability of oral trazodone averaged 70% to 90% and was unrelated to age or sex. In 23 obese subjects (mean weight 112 kg) vs. 23 matched control subjects of normal weight (mean 65 kg), Varea was greatly increased (162 vs. 67 L; 1.43 vs. 1.04 L/kg; P less than 0.001) and was highly correlated with body weight (r = 0.91). Clearance was unchanged between groups (146 vs. 136 ml/min), but the increased Varea caused prolonged t1/2 in obese subjects (13.3 vs. 5.9 hours; P less than 0.001). Reduced clearance of trazodone among elderly men may indicate a need for dosage reduction during chronic therapy. In obese individuals, choice of dosage during chronic treatment should be based on ideal rather than total body weight.
TL;DR: In this paper, the almost explosive growth of narrow sodium layers at altitudes near 95 km was observed by ground-based LIDAR located at 69°N, 16°E. Starting from typical conditions at these altitudes, the density is observed to increase by large factors within a few minutes in a narrow layer, the half height of which is typically 1 km only.
Abstract: The almost explosive growth of narrow sodium layers at altitudes near 95 km was observed by ground-based LIDAR located at 69°N, 16°E. Starting from typical conditions at these altitudes (sodium density approximately 1 to 2× 10³ cm−3) the density is observed to increase by large factors within a few minutes in a narrow layer, the half height of which is typically 1 km only. One of the more spectacular cases involved an increase by a factor 25 within 5 min and a layer width of 0.8 km (full width at half maximum). We propose that the sodium forming these sudden layers is released from upper atmospheric dust by energetic auroral particles. Prior to the auroral bombardment the dust particles were concentrated into a narrow layer by appropriate meteorological processes. Our observations thus imply that considerable amounts of sodium are stored on the surface of upper atmospheric dust.
TL;DR: In this article, the relationship between the inequality of income distributions and the social welfare they imply is investigated. But the authors focus on the trade-off between size and distribution of incomes.
TL;DR: In this article, the average strength and radial variation of the coronal magnetic field at solar minimum at solar distances from 3-10 solar radii were determined using the linearly polarized carrier signals of the Helios spacecraft.
Abstract: Coronal Faraday rotation of the linearly polarized carrier signals of the Helios spacecraft was recorded during the regularly occurring solar occultations over almost a complete solar cycle from 1975 to 1984 These measurements are used to determine the average strength and radial variation of the coronal magnetic field at solar minimum at solar distances from 3-10 solar radii, ie, the range over which the complex fields at the coronal base are transformed into the interplanetary spiral The mean coronal magnetic field in 1975-1976 was found to decrease with radial distance according to r exp-alpha, where alpha = 27 + or - 02 The mean field magnitude was 10 + or - 05 x 10 to the -5th tesla at a nominal solar distance of 5 solar radii Possibly higher magnetic field strengths were indicated at solar maximum, but a lack of data prevented a statistical determination of the mean coronal field during this epoch
01 Oct 1987
TL;DR: In this paper, it is shown how deadlocks and traps of a class of transition-nets can be calculated as S-invariants of marked graphs, where S is the length of the transition-net.
Abstract: It is shown how deadlocks and traps of a class of place/transition-nets can be calculated as S-invariants of marked graphs.
TL;DR: It is concluded that devices designed for EEG trend monitoring during anaesthesia should preferably depict a frequency measure, and allow for burst suppression recognition before spectral analysis.
Abstract: In 14 patients undergoing elective surgery the EEG was studied during anaesthesia with isoflurane and nitrous oxide (in oxygen) at 1.3 and 1.5 MAC. The distributions of spectral EEG indices of the baseline EEG, during the intra-operative and recovery periods were established and compared. Median frequency exhibited the most clear separation between the distributions during recovery and the intraoperative period. During anaesthesia, the median values were found to be lower than 5 Hz; when the patient was conscious, the EEG median frequency values were greater than 6 Hz. Time to recovery was 13.4±2.9 min and 30.0±8.5 min for the groups treated with 1.3 and 1.5 MAC, respectively. Burst suppression was observed during the loading period in all patients treated with 1.5 MAC and in five patients out of seven receiving 1.3 MAC. The average duration of the period of burst suppression was markedly greater in the group receiving 1.5 MAC than in the group receiving 1.3 MAC. It is concluded that devices designed for EEG trend monitoring during anaesthesia should preferably depict a frequency measure, and allow for burst suppression recognition before spectral analysis.
TL;DR: In this article, the UA5 Monte Carlo program, consisting of a non-diffractive event generator GENCL, a Diffractive Event Generator DIFFR and a tracking program, is described.
TL;DR: In this paper, the authors derived a contour integral representation for the four-point correlations of all primary operators in the conformally invariant two-dimensional SU(2) σ-model with Wess-Zumino term.
TL;DR: In this study, MZ twins proved to be less like one another than each person is to himself over time, however, this result might be because the EEG data were not optimal for the applied method of analysis, but the existence of true within-pair differences cannot be excluded.
TL;DR: This anatomical defect has now been demonstrated in vivo in four patients with Kallmann's syndrome by magnetic resonance imaging.
Abstract: Kallmann's syndrome is characterized by hypo-gonadotropic hypogonadism and anosmia. Postmortem studies have revealed either hypoplasia or aplasia of the rhinencephalon, respectively, in patients with hyposmia and anosmia. This anatomical defect has now been demonstrated in vivo in four patients with Kallmann's syndrome by magnetic resonance imaging.
TL;DR: Reduced uptake was observed in the left cerebral hemisphere contralateral to the cerebellar infarction with the most marked reduction in theleft premotor region, which might be explained by the functional depression of cerebello-ponto-thalamo-cerebral pathways.