[Quality of life at the end of live: experiences, models and perspectives]. / Lebensqualität am Lebensende: Erfahrungen, Modelle und Perspektiven.

The present paper gives an overview of theoretical concepts and empirical research on the issue of quality of life at the end of life with a focus on psychological concepts of lifelong development. Faced with severe illness, it seems that in old age the quality of life strongly depends on the individuals' potentials for developmental change. In addition, particular qualities of the spatial, social, and care context, taking the psychosocial, spiritual and practical competences and needs of the patients and their relatives into account, seem to lead to a higher degree of self determination and well-being. Empirical findings on the predictors of quality of life and of a "good death" are reported. Implications for an adequate care context at the end of life and research needs are discussed.

Organized cell swimming motions in Bacillus subtilis colonies: patterns of short-lived whirls and jets.

The swimming motions of cells within Bacillus subtilis colonies, as well as the associated fluid flows, were analyzed from video films produced during colony growth and expansion on wet agar surfaces. Individual cells in very wet dense populations moved at rates between 76 and 116 microm/s. Swimming cells were organized into patterns of whirls, each approximately 1,000 microm2, and jets of about 95 by 12 microm. Whirls and jets were short-lived, lasting only about 0.25 s. Patterns within given areas constantly repeated with a periodicity of approximately 1 s. Whirls of a given direction became disorganized and then re-formed, usually into whirls moving in the opposite direction. Pattern elements were also organized with respect to one another in the colony. Neighboring whirls usually turned in opposite directions. This correlation decreased as a function of distance between whirls. Fluid flows associated with whirls and jets were measured by observing the movement of marker latex spheres added to colonies. The average velocity of markers traveling in whirls was 19 microm/s, whereas those traveling in jets moved at 27 microm/s. The paths followed by markers were aligned with the direction of cell motion, suggesting that cells create flows moving with them into whirls and along jets. When colonies became dry, swimming motions ceased except in regions close to the periphery and in isolated islands where cells traveled in slow whirls at about 4 microm/s. The addition of water resulted in immediate though transient rapid swimming (> 80 microm/s) in characteristic whirl and jet patterns. The rate of swimming decreased to 13 microm/s within 2 min, however, as the water diffused into the agar. Organized swimming patterns were nevertheless preserved throughout this period. These findings show that cell swimming in colonies is highly organized.