University of Oxford

About: University of Oxford is a education organization based out in Oxford, Oxfordshire, United Kingdom. It is known for research contribution in the topics: Population & Context (language use). The organization has 99713 authors who have published 258108 publications receiving 12972806 citations. The organization is also known as: Oxford University & Oxon..

Adaptive radiation in a heterogeneous environment

Abstract: Successive adaptive radiations have played a pivotal role in the evolution of biological diversity1,2,3. The effects of adaptive radiation are often seen4,5,6, but the underlying causes are difficult to disentangle and remain unclear7,8,9. Here we examine directly therole of ecological opportunity and competition in driving genetic diversification. We use the common aerobic bacterium Pseudomonas fluorescens10, which evolves rapidly under novel environmental conditions to generate a large repertoire of mutants11,12,13. When provided with ecological opportunity (afforded by spatial structure), identical populations diversify morphologically, but when ecological opportunity is restricted there is no such divergence. In spatially structured environments, the evolution of variant morphs follows a predictable sequence and we show that competition among the newly evolved niche-specialists maintains this variation. These results demonstrate that the elementary processes of mutation and selection alone are suifficient to promote rapid proliferation of new designs and support the theory that trade-offs in competitive ability drive adaptive radiation14,15.

Quality of life measurement: bibliographic study of patient assessed health outcome measures

Abstract: Objectives: To assess the growth of quality of life measures and to examine the availability of measures across specialties. Design: Systematic searches of electronic databases to identify developmental and evaluative work relating to health outcome measures assessed by patients. Main outcome measures: Types of measures: disease or population specific, dimension specific, generic, individualised, and utility. Specialties in which measures have been developed and evaluated. Results: 3921 reports that described the development and evaluation of patient assessed measures met the inclusion criteria. Of those that were classifiable, 1819 (46%) were disease or population specific, 865 (22%) were generic, 690 (18%) were dimension specific, 409 (10%) were utility, and 62 (1%) were individualised measures. During 1990-9 the number of new reports of development and evaluation rose from 144 to 650 per year. Reports of disease specific measures rose exponentially. Over 30% of evaluations were in cancer, rheumatology and musculoskeletal disorders, and older people9s health. The generic measures—SF-36, sickness impact profile, and Nottingham health profile—accounted for 612 (16%) reports. Conclusions: In some specialties there are numerous measures of quality of life and little standardisation. Primary research through the concurrent evaluation of measures and secondary research through structured reviews of measures are prerequisites for standardisation. Recommendations for the selection of patient assessed measures of health outcome are needed.