Multiple Magnetic Bilayers and Unconventional Criticality without Frustration in BaCuSi_{2}O_{6}.

The dimerized quantum magnet BaCuSi_{2}O_{6} was proposed as an example of "dimensional reduction" arising near the magnetic-field-induced quantum critical point (QCP) due to perfect geometrical frustration of its interbilayer interactions. We demonstrate by high-resolution neutron spectroscopy experiments that the effective intrabilayer interactions are ferromagnetic, thereby excluding frustration. We explain the apparent dimensional reduction by establishing the presence of three magnetically inequivalent bilayers, with ratios 3∶2∶1, whose differing interaction parameters create an extra field-temperature scaling regime near the QCP with a nontrivial but nonuniversal exponent. We demonstrate by detailed quantum Monte Carlo simulations that the magnetic interaction parameters we deduce can account for all the measured properties of BaCuSi_{2}O_{6}, opening the way to a quantitative understanding of nonuniversal scaling in any modulated layered system.

Correlated decay of triplet excitations in the Shastry-Sutherland compound SrCu2(BO3)2.

The temperature dependence of the gapped triplet excitations (triplons) in the 2D Shastry-Sutherland quantum magnet SrCu(2)(BO(3))(2) is studied by means of inelastic neutron scattering. The excitation amplitude rapidly decreases as a function of temperature, while the integrated spectral weight can be explained by an isolated dimer model up to 10 K. Analyzing this anomalous spectral line shape in terms of damped harmonic oscillators shows that the observed damping is due to a two-component process: one component remains sharp and resolution limited while the second broadens. We explain the underlying mechanism through a simple yet quantitatively accurate model of correlated decay of triplons: an excited triplon is long lived if no thermally populated triplons are nearby but decays quickly if there are. The phenomenon is a direct consequence of frustration induced triplon localization in the Shastry-Sutherland lattice.

Magnetoelastic excitations in the pyrochlore spin liquid Tb2Ti2O7.

At low temperatures, Tb2Ti2O7 enters a spin liquid state, despite expectations of magnetic order and/or a structural distortion. Using neutron scattering, we have discovered that in this spin liquid state an excited crystal field level is coupled to a transverse acoustic phonon, forming a hybrid excitation. Magnetic and phononlike branches with identical dispersion relations can be identified, and the hybridization vanishes in the paramagnetic state. We suggest that Tb2Ti2O7 is aptly named a "magnetoelastic spin liquid" and that the hybridization of the excitations suppresses both magnetic ordering and the structural distortion. The spin liquid phase of Tb2Ti2O7 can now be regarded as a Coulomb phase with propagating bosonic spin excitations.

Low-frequency vibrational properties of nanocrystalline materials.

The vibrational density of states (VDOS) of bulk nanocrystalline Ni and Cu (model) samples with grain diameters between 5 and 12 nm are derived from molecular-dynamics simulations. The results show an enhancement of the density of states at low and high energies. Because of large system sizes and a decomposition of the VDOS into grain and grain-boundary components, the low-frequency region can be investigated for the first time. It is found that the anomalous increase of the VDOS is mainly caused by the high number of grain-boundary atoms and that a power-law behavior of the low-frequency grain-boundary VDOS exists, which suggests a reduced dimensionality effect.

Psychiatric conditions in patients with recurrent unexplained syncope.

AIMS: The relationship between syncope and psychiatric disorders is little investigated. This study evaluated the prevalence of psychiatric diseases and prognostic outcome in patients with recurrent unexplained syncope. METHODS AND RESULTS: After an inconclusive standard diagnostic work-up for syncope, including head-up tilt testing, a psychiatric evaluation was offered to 50 consecutive patients with recurrent syncope. The evaluation was accepted by 26 patients (77% females, 36 +/- 16 years) and refused by 24 (63% females, 50 +/- 19 years). A psychiatric disorder was diagnosed in 21 (81%) patients: 12 had depression, four panic attacks, two general anxiety, and three a somatization disorder. Only five patients showed normal psychosocial function. Of the patients with psychiatric disorders four accepted psychiatric care, such as psychotherapy and/or pharmacotherapy; 17 patients refused treatment. During 6 months of follow-up no patient under psychiatric care had syncope, while all patients without psycho- or pharmacotherapy had recurrent syncopal events. In these patients the median of syncopal episodes was three in a 6 months interval before and after clinical assessment. Patients who refused both psychiatric evaluation and therapy continued to experience syncope as before. CONCLUSIONS: In patients with recurrent unexplained syncope psychiatric alteration is common. However, patients seldom accepted a psychiatric evaluation and treatment.

[Taxonomic research approaches in psychosomatic medicine and psychotherapy]. / Taxonomische Forschungasansätze in Psychosomatik und Psychotherapie.

In a personal view the scientific achievements of A.-E. Meyer in the model and research concept of taxonomy in psychosomatic medicine and psychotherapy research are described and honored. There are given an overview and examples for the different fields the taxonomic approach is realized in Germany especially in asthma bronchiale and outcome psychotherapy research (time dynamic taxonomy). Finally there is an introduction in one approach of qualitative taxonomic research (Verstehende Typenbildung) applied in psychoanalytic follow-up research.

[Psychosomatic-psychosocial need and care status in an acute-care hospital--results of a survey of internal medicine medical staff]. / Die psychosomatisch-psychosoziale Bedarfs- und Versorgungssituation im Akutkrankenhaus--Ergebnisse einer Befragung internistischer Stationsärzte und -ärztinnen.

A questionnaire submitted in 1986 to ward physicians in internal medicine in 9 out of 11 public hospitals (eight General Hospitals and the University Hospital) in the city of Hamburg documents their remarkable awareness of psychosocial problems. Noticeable, however, is the comparably low assessment of the prevalence of psychosomatic diseases. The desire for assistance through a psychosomatic consultation service is much greater than actual rates of request. The status of psychosomatic care is judged to be very unsatisfactory. The collected data and the broad agreement to integrate psychosomatic forms of organization into the care of medical in-patients lead to the conclusion that there is an encouragingly great readiness to co-operate. Considering the very different experiences found in already existing models, the results indicate the necessity of a more in-depth examination of the process of co-operation between somatics and psychosomatics.

[Reports and clarification of "critical incidents" as promoting factors in psychotherapy. A process-efficiency study between psychodynamic and client-centered treatment of patients]. / Berichte über und Klärung von "kritischen Ereignissen" als Wirkfaktoren in der Psychotherapie. Eine Prozess-Effizienz-Studie zwischen psychodynamisch und klientzentriert behandelten Patienten.

Our investigation assays if (i) the patient's thematization of and (ii) the attained degree of psychological clarification of "critical incidents" (sensu Rice & Saperia) covariate with favourable outcomes of psychotherapies. The sample consisted of 16 short psychotherapies (maximum 30 sessions), half of which treated with client centered (= CC) and the other half with psychodynamic (= PT) psychotherapy. These had been classified in a previous investigation (on the basis of questionnaire scores in 5 points in time, covering 12 years) into 8 differing time courses. Significant results are: "Critical incidents" were more often found in PT than in CC, reciprocally "psychological clarification" was higher in CC. In sessions rated "good" and in the 10 "ameliorating" time courses "critical incidents" were more frequent than in their respective countergroup. A crass exception was furnished by the "deteriorating" subgroup's quite high frequencies.

[Results and problems of time series analysis of individual observations in client-centered and psychodynamic brief psychotherapy]. / Ergebnisse und Probleme zeitreihenanalytischer Einzelfallbetrachtungen bei klientenzentrierter und psychodynamischer Kurzpsychotherapie.

The longitudinal data of five psychotherapies, collected during the Hamburg Short Psychotherapy Comparison Experiment, were statistically reviewed by the method of time series analysis. The intention of the single case studies was to describe the therapist-patient-interactions in details for acquiring greater knowledge of the therapeutical process. The items to study were obtained by ratings. Although there were thirteen nonverbal characteristics of the therapist and the patient as well as one common feature of the relationship between them both. The results did not correspond with the theoretical expectations. There were only few changes in the behaviors of the therapists and the patients and there was little proof of mutual effects in their behaviors during the therapeutical process. Only one of the therapies showed a significant patient's reaction, but it was unexpectedly negativistic. This supports the idea, that the therapist's influence on the patient may not be very strong und may not necessarily be positive. However, there were some severe methodological data problems mainly concerning the applicability of the time series analysis. Nonequidistant measurements as well as the relative shortness of the time series made the validity of the results a topic to be discussed. In dealing with these problems, the necessity of conceptualizing the time structures of psychological processes became evident.

[The complexity problem and reductionist solutions--critical comments from the psychoanalytic viewpoint]. / Das Komplexitätsproblem und der reduktionistische Lösungsweg--kritische Anmerkungen aus psychoanalytischer Sicht.

We refer to the essentials of the complexity of psychosomatic and psychoneurotic phenomena and how to comprehend this complexity. Measurement is called in question as a possibility to describe psychic phenomena. We make a suggestion to preserve the advantages and to overcome the disadvantages (selective awareness, no generalization, no intersubjective validitation) of clinical psychoanalytic research work.

[A prevalence study of the need for psychosomatic services at the general hospitals in Hamburg]. / Eine Prävalenzstudie zum Bedarf an psychosomatischer Versorgung in den Allgemeinen Krankenhäusern Hamburgs.

Between 1981 and 1986 we took a random sample of patients in internal wards of 9 out of 11 General Hospitals. This study serves to determine the prevalence of psychosomatic diseases of in-patients and to ascertain the planned demand for psychosomatic care. We used a psychodynamically oriented half-standardized interview as well as questionnaires about the patients' opinion of the etiology respectively on their therapeutic expectations and on life events. 11.1% of the in-patients had been admitted due to psychiatric problems such as alcohol, suicidal tendencies. 38.4% of the thoroughly examined patients were identified as psychosomatic in accordance with the evaluation of the interview. Items of the lay-etiology and of the therapeutic expectations correlate with this identification; psychosomatic patients have more critical life events.

12-year follow-up study of the Hamburg short psychotherapy experiment: an overview.

In 1971/72 eighty-seven psychoneurotic and psychosomatic patients of the Psychosomatic Outpatient Department at the University Clinic of Hamburg-Eppendorf attained an indication for short-term psychotherapy. Nineteen patients did not accept our offer despite a sufficient prognosis; they form the nontreated control group. The remaining 68 patients were assigned at random to a psychodynamic conflict-centered (n = 34) or to a client-centered therapy (n = 34), each with a maximum of 30 sessions. In spite of this long interval of 12 years we gained information about 82.5% of our patients. The follow-up program consisted of a multidimensional approach to describe the posttreatment development of our patients: psychological tests, self-rating by the patient and assessments by the follow-up interviewer and independent ratings of experts. The efficacy of short psychotherapy is seen in the test scale 'extraversion' for both treatment groups, for 'depression' only for the client-centered therapy; for the psychodynamic therapy there is a tendency for late changes. The clinical ratings show no significant differences between the treatment and the control groups. Sex combination in the therapeutic dyads (i.e. same sex vs. opposite sex) is important for patients' posttherapeutic development.