We have investigated prospectively the efficacy of two nonpharmacologic relaxation techniques in the therapy of anxiety. A simple, meditational relaxation technique (MT) that elicits the changes of decreased sympathetic nervous system activity was compared to a self-hypnosis technique (HT) in which relaxation, with or without altered perceptions, was suggested. 32 patients with anxiety neurosis were divided into 2 groups on the basis of their responsivity to hypnosis: moderate-high and low responsivity. The MT or HT was then randomly assigned separately to each member of the two responsivity groups. Thus, 4 treatment groups were studied: moderate-high responsivity MT; low responsivity MT; moderate-high responsivity HT; and low responsivity HT. The low responsivity HT group, by definition largely incapable of achieving the altered perceptions essential to hypnosis, was designed as the control group. Patients were instructed to practice the assigned technique daily for 8 weeks. Change in anxiety was determined by three types of evaluation: psychiatric assessment; physiologic testing; and self-assessment. There was essentially no difference between the two techniques in therapeutic efficacy according to these evaluations. Psychiatric assessment revealed overall improvement in 34% of the patients and the self-rating assessment indicated improvement in 63% of the population. Patients who had moderate-high hypnotic responsivity, independent of the technique used, significantly improved on psychiatric assessment (p = 0.05) and decreased average systolic blood pressure from 126.1 to 122.5 mm Hg over the 8-week period (p = 0.048). The responsivity scores at the higher end of the hypnotic responsivity spectrum were proportionately correlated to greater decreases in systolic blood pressure (p = 0.075) and to improvement by psychiatric assessment (p = 0.003). There was, however, no consistent relation between hypnotic responsivity and the other assessments made, such as diastolic blood pressure, oxygen consumption, heart rate and the self-rating questionnaires. The meditaiional and self-hypnosis techniques employed in this investigation are simple to use and effective in the therapy of anxiety.

on-the-Naze (Essex, England) ate described (Psittacopes lepidus n. g., n. sp. and three unnamed species). These birds resemble the Recent Family Psittacidae in the morphology of the tarsometatarsus, bu~ exhibit distinct differences in other skeTelal elements, especially in the rather coly-like beak and in the wing skeleton. For the first time the presence of the Quercypsittidae MOURER-CHAuVfrU~ 1992 in the Lower Eoeene London Clay is demonstrated; this family differs distinctly from the four taxa mentioned above. Sinee new material of Palaeopsittacus georgei HARRlSON 1982 from the type locality shows that this bird was anisodactyl (and therefore nota member of the Psittaciformes), the Quereypsittidae only contain the genus Quercypsitta MOURER-CHAUVIRE 1992.K e y w o r d s : Aves, Psittaciformes, Quercypsittidae, taxonomy, Tertiary, Eocene, Messel, Germany. Kurzfassung[Eozfine Papageien von Messel (Hessen, Deutschland) und dem London Clay ron Walton-on-the-Naze (Essex, England).]-Es werden psittaciforme V6gel aus dem Mittel-Eoz~in von Messel (Hessen, Deutschland) und aus dem Unter-Eozfin des London Clay von Walton-on-the-Naze (Essex, England) besch¡ (Psittacopes tepidus n. g., n. sp. und dret unbenannte Arten). Diese V6gel/ihneln der rezenten FamiIie Psittacidae ira Bau des Tarsometatarsus, zeigen aber deut[iche Unterschiede in anderen Skelette[ementen, besonders im eher mausvogeI~,hnlichert Schnabel und ira Flª Die Quercypsittidae MOURER-CHAUVIR• 1992 werden erstmals aus dem Unter-Eoz~.n des London Clay nachgewiesen; diese Familie unterscheidet sich deutlich von den oben erw~ilmten vier Taxa. Da neues Material ron Palaeopsittacus georgei HAP,~SON 1982 aus der Typus-Lokalit~it zeigt, daB dieser Vogel anisodactyl war (und damit kein Vertreter der Psittaciformes), beinhalten die Quercypsittidae nur die Gattung Quercypsitta MOURER-CHAUVlR• 1992.

Microbial communities thrive in almost all habitats on earth. Within these communities, cells interact through the release and uptake of metabolites. These interactions can have synergistic or antagonistic effects on individual community members. The collective metabolic activity of microbial communities leads to changes in their local environment. As the environment changes over time, the nature of the interactions between cells can change. We currently lack understanding of how such dynamic feedbacks affect the growth dynamics of individual microbes and of the community as a whole. Here we study how interactions mediated by the exchange of metabolites through the environment change over time within a simple marine microbial community. We used a microfluidic-based approach that allows us to disentangle the effect cells have on their environment from how they respond to their environment. We found that the interactions between two species—a degrader of chitin and a cross-feeder that consumes metabolic by-products—changes dynamically over time as cells modify their environment. Cells initially interact positively and then start to compete at later stages of growth. Our results demonstrate that interactions between microorganisms are not static and depend on the state of the environment, emphasizing the importance of disentangling how modifications of the environment affects species interactions. This experimental approach can shed new light on how interspecies interactions scale up to community level processes in natural environments.

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Polysaccharide breakdown by bacteria requires the activity of enzymes that degrade polymers either intra- or extra-cellularly. The latter mechanism generates a localized pool of breakdown products that are accessible to the enzyme producers themselves as well as to other organisms. Marine bacterial taxa often show marked differences in the production and secretion of degradative enzymes that break down polysaccharides. These differences can have profound effects on the pool of diffusible breakdown products and hence on the ecological dynamics. However, the consequences of differences in enzymatic secretions on cellular growth dynamics and interactions are unclear. Here we study growth dynamics of single cells within populations of marine Vibrionaceae strains that grow on the abundant marine polymer alginate, using microfluidics coupled to quantitative single-cell analysis and mathematical modelling. We find that strains that have low extracellular secretions of alginate lyases aggregate more strongly than strains that secrete high levels of enzymes. One plausible reason for this observation is that low secretors require a higher cellular density to achieve maximal growth rates in comparison with high secretors. Our findings indicate that increased aggregation increases intercellular synergy amongst cells of low-secreting strains. By mathematically modelling the impact of the level of degradative enzyme secretion on the rate of diffusive oligomer loss, we find that enzymatic secretion capability modulates the propensity of cells within clonal populations to cooperate or compete with each other. Our experiments and models demonstrate that enzymatic secretion capabilities can be linked with the propensity of cell aggregation in marine bacteria that extracellularly catabolize polysaccharides.

Polysaccharide breakdown by bacteria requires the activity of enzymes that degrade polymers extracellularly. This generates a localized pool of breakdown products that are accessible to the enzyme producers themselves as well as to other organisms. Marine bacterial taxa often show marked differences in the production and secretion of degradative enzymes that break down polysaccharides. These differences can have profound effects on the pool of diffusible breakdown products and hence on the ecological dynamics. However, the consequences of differences in enzymatic secretions on cellular growth dynamics and interactions are unclear. Here we combine experiments and models to study the growth dynamics of single cells within populations of marine Vibrionaceae strains that grow on the abundant marine polymer alginate, using microfluidics coupled to quantitative single-cell analysis and mathematical modelling. We find that strains that have low extracellular secretions of alginate lyases show stronger aggregative behaviors compared to strains that secrete high levels of enzymes. One plausible reason for this observation is that low secretors require a higher cellular density to achieve maximal growth rates in comparison with high secretors. Our findings indicate that increased aggregation increases intercellular synergy amongst cells of low-secreting strains. By mathematically modelling the impact of the level of degradative enzyme secretion on the rate of oligomer loss to diffusion, we find that enzymatic capability modulates the propensity of cells within clonal populations to cooperate or compete with each other. Our experiments and models demonstrate that marine bacteria display distinct aggregative behaviors and intercellular interactions based on their enzymatic secretion capabilities when growing on polysaccharides.

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