The mobility of nitrogen across tree-rings of Norway spruce (Picea abies L.) and the effect of extraction method on tree-ring δ¹5N and δ¹³C values.

RATIONALE: The use of stable nitrogen (N) isotope ratios (δ(15)N values) in dendroecological studies is often preceded by an extraction procedure using organic solvents to remove mobile N compounds from tree-rings. Although these mobile N compounds may be capable of distorting potential environmental signals in the tree-ring δ(15)N values, recent investigations question the necessity of such an extraction. METHODS: We used an on-going experiment with simulated elevated N deposition previously labelled with (15)N, in conjunction with control trees, to investigate the necessity of extracting mobile N compounds (using a rapid extraction procedure) for tree-ring δ(15)N and δ(13)C studies, as well as N and C concentration analyses. In addition, we examined the magnitude of radial redistribution of N across tree-rings of Norway spruce (Picea abies). RESULTS: The (15)N label, applied in 1995/96, was found in tree-rings as far back as 1951, although the increased N availability did not cause any significant relative increase in tree growth. The rapid extraction procedure had no significant effect on tree-ring δ(15)N or δ(13)C values in either labelled or control trees, or on N concentration. The C concentrations, however, were significantly higher after extraction in control samples, with the opposite effect observed in labelled samples. CONCLUSIONS: Our results indicate that the extraction of mobile N compounds through the rapid extraction procedure is not necessary prior to the determination of Norway spruce δ(15)N or δ(13)C values in dendrochemical studies. δ(15)N values, however, must be interpreted with great care, particularly when used as a proxy for the N status of trees, due to the very high mobility of N within the tree stem sapwood of Norway spruce over several decades.

[Positive role of family in coping with schizophrenic illness]. / Die positive Rolle der Angehörigen in der Bewältigung schizophrener Erkrankungen.

Research on the influence of family variables on the course of schizophrenia has mainly centered on the concept of expressed emotions. The emphasis of this construct is centering predominantly on potentially destructive aspects of family behaviour. The authors criticize approach as too biased towards the negative. From their clinical practice and a review of the literature, the authors argue for a more positive view of relatives' role in rehabilitation, relapse prevention and coping with schizophrenia.

[Interpersonal therapy of depression--an integrative approach for clinical practice]. / Interpersonelle Therapie der Depression--ein integrativer Ansatz für die Praxis.

Interpersonal therapy of depression (IPT) has proven to be very effective in a comparative study of therapeutic modalities for the treatment of depression. It reflects contemporary research on the etiology and the nosology of depressive disorders and offers a multifactorial treatment concept. Specifically, IPT integrates aspects of biological vulnerability for depression with the psychosocial context of a person. Disturbed social relations are seen as possible causes as well as consequences of depressive disorders. IPT has the goal to reduce depressive symptomatology and to improve interpersonal functioning. It emphasizes the structured diagnosis of depression in order to help the patient to better understand his condition. Symptoms are then related to his or her interpersonal context. Therapy sessions deal with four problem areas: Grief over loss, interpersonal disputes, role transitions, and interpersonal deficits. When necessary, prescribing medication is an integral part of the therapeutic procedure. The article gives an overview of the literature and the therapeutic strategies of IPT which seems especially effective for the treatment of mild to moderate depressions in primary care.