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The authors derive the expression of a model many-body one-point function, which appears in effective many body Hamiltonians, in the framework of a loop expansion by using the replica variable technique. They show the specific properties of the effective Lagrangian appearing in the integral expression of the propagator. They analyse the properties of the lowest-lower expansion terms in the conventional saddle-point approach and discuss other possible developments.

Fragmentation is expected to be an experimental signal which can give some information about the physical characteristics of finite excited systems. We try to investigate the question concerning the mechanism which governs the onset of the disassembly of such systems in connection with their internal dynamics. We restrict this study to the case where the systems are in thermodynamical equilibrium. We use the 2-dimensional Ising model as a generic model in order to calculate the multiplicities for the formation of strongly bound clusters inside the system and analyse their behaviour as a function of the temperature. The calculated observables show features which reflect the role played by the internal dynamics. The evolution of the shape of the cluster multiplicities with temperature obtained in the present study is qualitatively the same as the one which comes out through different nuclear phase space fragmentation models.

The statistical aspects of cluster distributions as a decisive factor in high energy nuclear fragmentation are studied on a finite lattice model. The qualitative behaviour of the mass spectra is understood in terms of a simple model in which finite space constraints play the main role. Both, the light and the heavy mass sector of the spectrum are derived analytically. In the low density regime the model includes those results of Fisher's condensation theory which are frequently applied to nuclear fragmentation.

Different choices of effective interactions and operators are related to each other and to definitions given in the literature. Perturbation expansions are given, and the degree of complexity in evaluating terms of a given order is exhibited. The application of Pade approximants to different choices of effective interactions and to effective operators is investigated numerically.

The relationships of client prognostic expectations and of level of Experiencing in psychotherapy with three variables of therapeutic change were explored in a correlational study that used 26 volunteer Ss who were in treatment with experienced therapists. A positive relationship was found between prognostic expectation and perceived improvement and a negative relationship between Experiencing and perceived improvement. The data also suggested positive relationships between Experiencing and cognitive change and attitude and cognitive change, while they provided no evidence for a relation between expectations and cognitive change.

We use measured isotopic yields of fragments produced in the reaction 40 Ar on 68 Zn at 27.6 MeV/nucleon in order to see whether these quantities may constitute a test which allows to gain some insight into the projectile fragmentation process. We compare the experimental distributions to those obtained with the multisequential decay model which we developed previously, the projectile break-up model proposed by Friedman and abrasion-ablation model calculations.

This work deals with the exact integration of a Fokker-Planck equation for the mass distribution in heavy ion collisions. The results are compared to those obtained in a previous calculation in which the distribution is approximated by its two lowest moments.

Pancreatic function tests were performed in 15 patients with advanced renal insufficiency. Pancreatic secretion was stimulated with CCK/PZ and secretin and 60 minutes later with bile given intraduodenally and CCK/PZ and secretin intravenously. The Wilcoxon-test showed that there were significantly higher lipase levels in serum and lower amylase amounts in duodenal juice compared to normal volunteers. No differences could be demonstratd for volume, maximal bicarbonate concentration, lipase and trypsin outputs. It could be shown by nonlinear discriminant analysis that pancreatic secretion might specifically be changed in patients with chronic renal failure. These patients can be definitely differentiated according to the secretion pattern from normal controls and patients with chronic pancreatitis, pancreatic carcinoma, chronic and acute duodenal ulcer.

This paper deals with the contribution to the reaction cross section coming from the break-up of an interacting complex of two fragments which is trapped in a pocket of the relative potential acting between the fragments. Calculations for the systems S on Co and S on Ge are done by using the semi-classical expression of tunneling through the barrier and the statistical break-up probability. The results are discussed and conclusions about the reaction mechanism are drawn.

Heavy-ion collision processes at energies above the Coulomb barrier are investigated by an explicit introduction of intrinsic degrees of freedom of the ions. The description relies on a model which can be derived from quantal evolution equations and which is expected to work for low bombarding energies and peripheral collisions. The classical motion of the collective degree of freedom is coupled to the rate equations which govern the variation of the time-dependent single particle level occupation probabilities. The behaviour of physical observables for a specific system is analysed. The results are compared to those obtained with a realistic friction model. The problem raised by the expected irreversible character of the reaction process is discussed.

Using the path integral formalism and a model based on statistical arguments, we derive the correlation function which enters the description of a one-dimensional collective system coupled to an intrinsic system in terms of transport concepts. The derivation shows a finite time dependence of the correlation function in contradistinction to a former calculation. We discuss some points related to the derivation and estimate the relaxation times which characterise the memory effects in both cases of weak and strong coupling.

We present here a quantitative study of the classical and quantum mechanical distribution functions of an open subsystem coupled to an external subsystem in the framework of a model whose physical characteristics are typical of those corresponding to heavy ion collision physics. The formalism is based on a path integral approach. We analyse the time correlation effects generated by the coupling between the two subsystems on the evolution of the classical distribution functions. In a second step we compare the results obtained in the quantum mechanical case to those obtained in the classical case.

The reactions of32S on59Co,65Cu,74Ge,79Br,85Rb,89Y are studied. An explanation for the specific shape of the double differential cross sections as a function of the scattering angle and the mass asymmetry is given in the framework of a transport model. Conclusions about the reaction mechanism are drawn.

Die Symptome der akuten Bleivergiftung wurden in den vergangenen Jahrhunderten immer wieder beobachtet und sind vor allem mit der fruhen industriellen Entwicklung verknupft. Uber den Zusammenhang zwischen chronischer Bleivergiftung und Niereninsuffizienz wurde in der uns bekannten Literatur erstmals 1863 berichtet [6] und hier verdient besondere Erwahnung die Studie von Henderson [3], der 1954 die Haufung todlicher Uramien bei jungen Erwachsenen in Queensland/Australien auf die Inkorporation bleihaltiger Farben in der Kindheit zuruckfuhren konnte. Der Fall der Patientin, uber den wir hier berichten, ist vom Verlauf her ahnlich, von der Atiologie aber als seltener Einzelfall anzusehen. Was uns besonders wichtig erscheint, ist die lange Latenz zwischen auslosendem Ereignis und dem Auftreten der Erkrankung, die Schwierigkeit in einer beweisenden Diagnostik und nicht zuletzt Bezuge zu unserer okologischen Situation.

Bei 15 Patienten mit fortgeschrittener Niereninsuffizienz wurden Pankreasfunktionsprufungen durchgefuhrt. Die Pankreassekretion wurde mit Cholecystokinin/Pankreozymin (CCK/PZ) und Secretin sowie mit Galle, CCK/PZ und Secretin stimuliert. Mit dem Wilcoxon-Test liesen sich im Serum signifikant hohere Lipasewerte, im Duodenalsaft signifikant niedrigere Amylasemengen nachweisen als bei Gesunden. Keine Unterschiede bestanden bei der Saftmenge, der maximalen Bikarbonatkonzentration sowie der Bikarbonat-, Lipase- und Trypsinmenge. Bei einer multivariablen nichtlinearen Diskriminanzanalyse ergab sich, das bei chronischer Niereninsuffizienz die Pankreassekretion moglicherweise krankheitsspezifisch verandert ist. Sie last sich mit diesem statistischen Verfahren sicher von dem Sekretionsverhalten Gesunder sowie von Patienten mit chronischer Pankreatitis, Pankreascarcinom sowie mit chronischem und akutem Ulcus duodeni unterscheiden.

A hormone-dependent subline of the transplantable rat mammary tumor MTW9 contains binding sites for both prolactin and estrogen. Prolactin binding is saturable (K-d similar to 2 times 10-9 M), hormone specific, and destroyed by proteases. By contrast, an autonomous subline derived from the same parent tumor has lost more than 75% of both prolactin- and estrogen-binding sites, although binding affinities for both hormones are unchanged. This reduction in binding sites for both prolactin and estrogen in the autonomous line may result in an incomplete recognition of the tumor cells as a target for the circulating hormones with a subsequent loss of hormone-dependent growth characteristics.

Using a random-matrix model to describe the coupling between a collective nuclear variable and the other (intrinsic) degrees of freedom and the functional integral approach, we derive and discuss the mass (or inertial) parameter for the collective variable in the high-temperature limit. The calculations are performed by using both a fixed and the adiabatic basis for the intrinsic states, and the results are given for both the weak- and the strong-coupling limit between collective and intrinsic degrees of freedom. The results are evaluated numerically, discussed, and compared with the formulas obtained from the cranking model and linear response theory.

The effects induced by the presence of an inertia term in the collective description of mass transfer are analysed in the framework of a transport model. The model is applied to the study of the collision of S on Ge. The transfer regime is shown to be quasi-oscillatory. The main differences with the overdamped regime are described. The implication of the presence of inertia terms on physical observables like differential cross sections is discussed.

The disassembly of an excited nuclear aggregate is described as a time-dependent decay process in which clusters are continuously and sequentially emitted by the primitive aggregate and those which have already been formed at a given time. The dynamics describe the rate at which the different species are generated as well as the rate at which the system de-excites and expands isotropically in space. The model is applied to the study of sequentially decaying40Ar as a function of the initial excitation energy.

Seit dem ersten Bericht von Black und Mitarb. [7] sind uber die Kortisonkatarakt zahlreiche Berichte veroffentlicht worden [2, 9, 11, 13, 14, 18, 21, 22, 27, 28, 29, 31, 34, 37, 39, 40]. Auch bei Nierentransplantierten, die zur Hemmung der immunbiologischen Abwehrreaktionen uber langere Zeit u. a. Kortikosteroide erhalten haben, wurden gehauft Katarakte beobachtet [17, 20, 24, 32].

Erosive lichen planus: beyond the nails.

École thématique