Temporal variability in detritus resource maintains diversity of bacterial communities

Competition theory generally predicts that diversity is maintained by temporal environmental fluctuations. One of the many suggested mechanisms for maintaining diversity in fluctuating environments is the gleaner-opportunist trade-off, whereby gleaner species have low threshold resource levels and low maximum growth rates in high resource concentration while opportunist species show opposite characteristics. We measured the growth rates of eight heterotrophic aquatic bacteria under different concentrations of chemically complex plant detritus resource. The growth rates revealed gleaner-opportunist trade-offs. The role of environmental variability in maintaining diversity was tested in a 28-day experiment with three different resource fluctuation regimes imposed on two four-species bacterial communities in microcosms. We recorded population densities with serial dilution plating and total biomass as turbidity. Changes in resource availability were measured from filter-sterilised medium by re-introducing the consumer species and recording short-term growth rates. The type of environmental variation had no effect on resource availability, which declined slowly during the experiment and differed in level between the communities. However, the slowly fluctuating environment had the highest Shannon diversity index, biomass, and coefficient of variation of biomass in both communities. We did not find a clear link between the gleaner-opportunist trade-off and diversity in fluctuating environments. Nevertheless, our results do not exclude this explanation and support the general view that temporal environmental variation maintains species diversity also in communities feeding chemically complex resource.     

Developing a global psychotherapeutic approach to schizophrenia: results of a five-year follow-up

This is an account of a long-range action research project to determine indications for and effects of a comprehensive psychotherapeutic approach, including various treatment modalities, in the treatment of schizophrenics. Four diagnostic groups were established among the 100 patients. In the course of data analysis, the group of typical schizophrenics (56 percent) was contrasted to or compared with the entire series. A further diagnostic differentiation was established according to ego functioning; i.e., imminent, acute, regressive, and paranoid ego disintegrations, respectively. Patients and family members were interviewed upon admission, and again two and five years later, and the data recorded on a 163-item form from which 40 clinical and psychosocial variables were constructed after the baseline examinations. In addition to cross-tabulation, logistic regression analysis was employed. The conclusion that the follow-up study supports the effectiveness of our global psychotherapeutic approach to treating schizophrenia seems justified. Results so far indicate that five modes of therapy in addition to drug treatments are optimal for different patients. The five modes are long-term individual psychotherapy, couple or conjoint family therapy for married patients, family therapy with the family of origin, flexible short-term crisis intervention with a family focus, and extensive long-term treatment focused on social rehabilitation for the most ill-starred patients.     

Effects of outplanting time on growth,shedding and quality of Saccharina latissima (Phaeophyceae) in its northern distribution range

Journal of Applied Phycology - To reach the goal of large-scale seaweed cultivation in Norway and the rest of Europe, new knowledge about the commercially important kelp species Saccharina...     

Biogeography and ecology of freshwater chrysophyte cysts in Finland

Hydrobiologia - The occurrence of various chrysophyte cyst morphotypes is unknown in Finland, with the exception of a few isolated lake studies. We set out to chart which cyst types are found in...     

The Influence of AA29504 on GABAA Receptor Ligand Binding Properties and Its Implications on Subtype Selectivity

Neurochemical Research - The unique pharmacological properties of δ-containing γ-aminobutyric acid type A receptors (δ-GABAARs) make them an attractive target for selective and...