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- Jenkins, S. R., et al.
(författare)
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Population dynamics of the intertidal barnacle Semibalanus balanoides at three European locations: spatial scales of variability
- 2001
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Ingår i: Marine Ecology Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 217, s. 207-217
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Tidskriftsartikel (refereegranskat)abstract
- Spatial variability in the population dynamics of the intertidal acorn barnacle Semibalanus balanoides was investigated using a hierarchical sampling programme. Variability in a number of population parameters (size distribution, density, % cover, absolute growth and instantaneous mortality) was determined separately for new recruits and adults over 3 spatial scales. Three locations, SW Ireland, the Isle of Man and the west coast of Sweden, which cover a large part of the European range of this species, were selected to investigate variability over a large spatial scale (100s of kilometres). Two smaller scales, shore (1000s of metres) and site (10s of metres) nested within each location were also used. In addition, temporal variation over two 6 mo periods was also examined in the Isle of Man and Ireland. Most variability for all population parameters occurred over the largest spatial scale (location). This was a direct result of differences between Sweden and the other 2 locations, the Isle of Man and Ireland, which showed highly similar levels of all population parameters. The population of S, balanoides at the Swedish location was characterised by high growth rates, large size, high levels of mortality and a large turnover of bare space. At the spatial scale 'shore', only 1 population parameter, the growth rate of recruits, showed variability. At the smallest scale of 'site', all parameters showed significant variability except growth rate of adults. Calculation of variance components showed that differences between replicates (spatial scale: <0.5 m) accounted for little of the overall variability, in general less than the scales of site and shore. Examination of temporal variability over two 6 mo periods revealed no difference between time periods and no significant interaction between temporal and spatial scales, Thus, there was consistency of spatial variability over time. The potential causes of variability in population parameters of S, balanoides at different spatial scales and the implications for future studies are discussed.
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| 2. |
- Jenkins, S. R., et al.
(författare)
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Spatial and temporal variation in settlement and recruitment of the intertidal barnacle Semibalanus balanoides (L.) (Crustacea : Cirripedia) over a European scale
- 2000
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Ingår i: Journal of Experimental Marine Biology and Ecology. - 0022-0981. ; 243:2, s. 209-225
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Tidskriftsartikel (refereegranskat)abstract
- Variation in the level of settlement and recruitment in the intertidal barnacle Semibalanus balanoides was studied using a hierarchical sampling programme. The effect of three spatial scales, 10s of metres (sites), 1000s of metres (shores) and 100s of kilometres (locations), was determined. The largest spatial scale represented the distance between four widely separated locations, Sweden, the Isle of Man, SW Ireland and SW England, covering a. large part of the range of S. balanoides in Europe. Temporal variation was determined by comparison between two years, 1997 and 1998. The settlement period of S. balanoides varied in length and timing, being earlier and shorter at the most northerly location, Sweden. The duration of settlement showed little difference among shores within locations, but the pattern of settlement did vary. Estimates of total settlement throughout the settlement period and of recruitment at the end of this period both showed substantial variation among locations which was dependent on the year of study. There was little consistency in the ranking of locations between the two years. Recruitment showed significant variation I the lower spatial scales of shore and site. In addition, examination of variance components showed a high degree of variation between replicates within sites in 1997. There was a significant relationship between settlement and recruitment at three of the four locations. Across all locations variation in settlement explained between 29 and 99% of variation in recruitment. However, locations showed distinct differences in the level of post-settlement survival. (C) 2000 Elsevier Science B.V. All rights reserved.
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| 3. |
- Fernandes, S, et al.
(författare)
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Beta-galactosidase from a cold-adapted bacterium: purification, characterization and application for lactose hydrolysis.
- 2002
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Ingår i: Applied Microbiology and Biotechnology. - : Springer Science and Business Media LLC. - 1432-0614 .- 0175-7598. ; 58:3, s. 313-321
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Tidskriftsartikel (refereegranskat)abstract
- The enzyme beta-galactosidase was purified from a cold-adapted organism isolated from Antarctica. The organism was identified as a psychrotrophic Pseudoalteromonas sp. The enzyme was purified with high yields by a rapid purification scheme involving extraction in an aqueous two-phase system followed by hydrophobic interaction chromatography and ultrafiltration. The beta-galactosidase was optimally active at pH 9 and at 26 degrees C when assayed with o-nitrophenyl-beta-D-galactopyranoside as substrate for 2 min. The enzyme activity was highly sensitive to temperature above 30 degrees C and was undetectable at 40 degrees C. The cations Na+, K+, Mg2+ and Mn2+ activated the enzyme while Ca2+, Hg2+, Cu2+ and Zn2+ inhibited activity. The shelf life of the pure enzyme at 4 degrees C was significantly enhanced in the presence of 0.1% (w/v) polyethyleneimine. The pure beta-galactosidase was also evaluated for lactose hydrolysis. More than 50% lactose hydrolysis was achieved in 8 h in buffer at an enzyme concentration of 1 U/ml, and was increased to 70% in the presence of 0.1% (w/v) polyethyleneimine. The extent of lactose hydrolysis was 40-50% in milk. The enzyme could be immobilized to Sepharose via different chemistries with 60-70% retention of activity. The immobilized enzyme was more stable and its ability to hydrolyze lactose was similar to that of the soluble enzyme.
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| 4. |
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| 5. |
- Micheli, A, et al.
(författare)
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Cancer prevalence in European registry areas
- 2002
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Ingår i: Annals of Oncology. - : Elsevier BV. - 1569-8041 .- 0923-7534. ; 13:6, s. 840-865
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Information on cancer prevalence is of major importance for health planning and resource allocation. However, systematic information on cancer prevalence is largely unavailable. MATERIALS AND METHODS: Thirty-eight population-based cancer registries from 17 European countries, participating in EUROPREVAL, provided data on almost 3 million cancer patients diagnosed from 1970 to 1992. Standardised data collection and validation procedures were used and the whole data set was analysed using proven methodology. The prevalence of stomach, colon, rectum, lung, breast, cervix uteri, corpus uteri and prostate cancer, as well as of melanoma of skin, Hodgkin's disease, leukaemia and all malignant neoplasms combined, were estimated for the end of 1992. RESULTS: There were large differences between countries in the prevalence of all cancers combined; estimates ranged from 1170 per 100000 in the Polish cancer registration areas to 3050 per 100000 in southern Sweden. For most cancers, the Swedish, Swiss, German and Italian areas had high prevalence, and the Polish, Estonian, Slovakian and Slovenian areas had low prevalence. Of the total prevalent cases, 61% were women and 57% were 65 years of age or older. Cases diagnosed within 2 years of the reference date formed 22% of all prevalent cases. Breast cancer accounted for 34% of all prevalent cancers in females and colorectal cancer for 15% in males. Prevalence tended to be high where cancer incidence was high, but the prevalence was highest in countries where survival was also high. Prevalence was low where general mortality was high (correlation between general mortality and the prevalence of all cancers = -0.64) and high where gross domestic product was high (correlation = +0.79). Thus, the richer areas of Europe had higher prevalence, suggesting that prevalence will increase with economic development. CONCLUSIONS: EUROPREVAL is the largest project on prevalence conducted to date. It has provided complete and accurate estimates of cancer prevalence in Europe, constituting essential information for cancer management. The expected increases in prevalence with economic development will require more resources; allocation to primary prevention should therefore be prioritised.
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