| 1. |
- Dynesius, Mats, et al.
(författare)
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Intercontinental similarities in riparian-plant diversity and sensitivity to river regulation.
- 2004
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Ingår i: Ecological Applications. - : Wiley. - 1051-0761 .- 1939-5582. ; 14:1, s. 173-191
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Tidskriftsartikel (refereegranskat)abstract
- We asked whether assemblages of species with separate evolutionary histories differed in their response to similar human interventions. We assessed this by comparing the response of riparian plant communities to river regulation on two different continents. We compared free-flowing and regulated rivers between boreal parts of North America (Alberta and British Columbia) and Europe (Sweden), using a standardized Sampling protocol and the same field staff on both continents. Although the two regions shared few species, both riparian plant-species diversity along free-flowing rivers and the response to different kinds of flow regulation were similar between the continents. The number of riparian-plant species and their amount of cover differed among types of water-level regime, but the continental affiliation of a river-margin site did not statistically explain any of the variation. Within continents, the local flora of the regulated river-margin sites was largely similar in species composition to the free-flowing ones, but the sites along storage reservoirs were more species-poor. The similarity in the response to regulation between the continents suggests that general guidelines for rehabilitation of degraded boreal rivers are. a realistic goal.The number of species and genera, plant cover, and species numbers in most trait groups (classified according to growth form and life span) were similar between free-flowing river margins in Europe and North America. Moreover, the regional native species pools of northern Sweden and Alberta were similar in size and composition of species groups, despite the fact that only 27% of the species in Alberta were found in northern Sweden. This is presumably because the floras share a common Tertiary origin and because the regions have had largely similar late-Tertiary and Quaternary histories. The most pronounced difference between the continents was that we found no exotic species on the 183 Swedish river margin sites, whereas 9% of the species found in all 24 North American plots taken together were exotics. All North American exotics found have occurred in Europe since prehistoric times, and the difference in exotic richness most likely reflects a difference in the number of species humans have transferred from one continent to another, rather than a difference in invasibility between the regions.
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| 2. |
- Nilsson, Christer, et al.
(författare)
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Secondary Acute Myeloid Leukemia and the Role of Allogeneic Stem Cell Transplantation in a Population-Based Setting
- 2019
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Ingår i: Biology of blood and marrow transplantation. - : Elsevier. - 1083-8791 .- 1523-6536. ; 25:9, s. 1770-1778
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Tidskriftsartikel (refereegranskat)abstract
- Secondary AML (s-AML), including AML with an antecedent hematologic disorder (AHD-AML) and therapy-related AML (t-AML), constitutes a large proportion of patients with AML and is considered to confer a dismal prognosis. The role of allogeneic hematopoietic cell transplantation (HCT) in patients with s-AML and the extent to which HCT is performed in these patients has been little studied to date. We used the population-based Swedish AML Registry comprising 3337 intensively treated adult patients over a 17-year period to study the role of HCT within the group of patients with s-AML as well as compared with patients with de novo AML. HCT was performed in 576 patients (22%) with de novo AML, in 74 patients (17%) with AHD-AML, and in 57 patients (20%) with t-AML. At 5 years after diagnosis, there were no survivors among patients with previous myeloproliferative neoplasms who did not undergo HCT, and corresponding survival for patients with antecedent myelodysplastic syndromes and t-AML was and 2% and 4%, respectively. HCT was compared with chemotherapy consolidation in s-AML using 3 models: (1) a 200-day landmark analysis, in which HCT was favorable compared with conventional consolidation (P = .04, log-rank test); (2) a multivariable Cox regression with HCT as a time-dependent variable, in which the hazard ratio for mortality was 0.73 (95% confidence interval, 0.64 to 0.83) for HCT and favored HCT in all subgroups; and (3) a propensity score matching analysis, in which the 5-year overall survival (OS) and relapse-free survival in patients with s-AML in first complete remission (CR1) was 48% and 43%, respectively, for patients undergoing HCT versus 20% and 21%, respectively, for those receiving chemotherapy consolidation (P = .01 and .02, respectively, log-rank test). Our observational data suggest that HCT improves survival and offers the only realistic curative treatment option in patients with s-AML.
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| 3. |
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| 4. |
- Dynesius, Mats, et al.
(författare)
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High resilience of bryophyte assemblages in streamside compared to upland forests
- 2009
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Ingår i: Ecology. - : Ecological Society of America. - 0012-9658 .- 1939-9170. ; 90:4, s. 1042-1054
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Tidskriftsartikel (refereegranskat)abstract
- Landscape heterogeneity causes spatial variation in disturbance regimes and resilience. We asked whether the resilience of bryophyte (liverwort and moss) assemblages to clear-cutting differs between streamside and upland boreal forests in northern Sweden. We hypothesized that bryophyte survival and recolonization rates are higher in streamside areas, thus raising resilience. Conversely, disturbance-intolerant but also invading species should be more frequent here, potentially reducing resilience. In each of 18 sites, we compared two 0.1-ha plots (one streamside and one upland) located in old forest that had never been clear-cut with two matching plots in young stands established after clear-cutting of old forests 30-50 years earlier. We used the magnitude of the difference in assemblages between old and young stands as a measure of change and, therefore, resilience (large difference implying low resilience). Species assemblages were more resilient in streamside than in upland forests. Species composition changed significantly in upland but not in streamside forests. Reductions in species richness were more pronounced in upland forests for total richness and for eight subgroups of species. Two results indicated lower survival/recolonization in upland forests: (1) species had a stronger association with old stands in upland areas, and (2) among species present in both the old streamside and old upland plot in a site, fewer appeared in the young upland than in the corresponding streamside plot. Simultaneously, a higher proportion of species invaded streamside areas; 40 of the 262 species encountered in streamside forests increased their occupancy by two or more sites compared to only two of 134 species in uplands. We suggest that in boreal forests spatial variation in resilience of assemblages of forest organisms intolerant of canopy removal is related to factors governed mainly by topography. More generally, we argue that landscape-scale variation in resilience of assemblages is influenced by spatial variation in (1) stress and resource availability, (2) number of disturbance intolerant species, and (3) magnitude of environmental changes brought about by a disturbance with a specific intensity. We also suggest that rapid recovery in the short term does not necessarily imply higher long-term ability to return to the pre-disturbance state.
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| 5. |
- Dynesius, Mats, et al.
(författare)
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Microclimatic buffering by logging residues and forest edges reduces clear-cutting impacts on forest bryophytes
- 2008
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Ingår i: Applied Vegetation Science. - : Wiley. - 1402-2001 .- 1654-109X. ; 11:3, s. 345-354
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Tidskriftsartikel (refereegranskat)abstract
- Question: The practice of extracting logging residues after clear-cutting for bioenergy purposes is spreading. Logging residues constitute a shelter in clear-cut areas and therefore concerns have been expressed that their removal could make the ground and its vegetation more exposed to extreme micro¬climatic conditions. We asked whether logging residues and forest edges can protect ground-dwelling forest bryophytes from fatal microclimate events following clear-cutting.Location: Boreal forests of central Sweden.Methods: Using transplants of eight forest floor bryophyte species we experimentally analysed the sheltering effect (less solar radiation and less wind) of logging residues and forest edges in seven clear-cut areas. Transplants were placed in two contrasting positions in each area; near a north-facing forest edge and in the centre of the clear-cut area. In each position, half of the transplants were covered by a layer of spruce branches and the other half was left uncovered. We estimated proportion of apparently living shoots (apparent vitality) and measured radial growth of transplants during one growing season.Results: Position in the clear-cut area, but not cover of spruce branches, clearly influenced radial growth. Vitality scores were higher among transplants covered with branches and the lowest apparent vitality was observed in uncovered transplants in the middle of clear-cut areas. The change in area of apparently liv¬ing shoots during the course of the experiment (growth minus mortality) was unaffected by branch cover close to the edge but positively affected in the centre of the clear-cut area. In general, the effect of branch cover on bryophytes was higher in the centre of clear-cut areas. Here, climatic measurements showed that branch cover buffers during periods of extreme microclimates.Conclusions: Extraction of logging residues after clear-felling may reduce the survival of some ground-dwelling forest organisms. The additional sheltering provided by branches was unimportant close to forest edges. We suggest smaller clear-cut areas, green-tree retention and other ways to make logged areas shadier and less windy to mitigate the reduced shelter caused by harvest of logging residues.
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| 6. |
- Hellquist, Henrik B., et al.
(författare)
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Salivary duct carcinoma : a highly aggressive salivary gland tumour with overexpression of c-erbB-2
- 1994
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Ingår i: Journal of Pathology. - West Sussex, United Kingdom : John Wiley & Sons. - 0022-3417 .- 1096-9896. ; 172:1, s. 35-44
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Tidskriftsartikel (refereegranskat)abstract
- The clinicopathological and immunocytochemical features of nine cases of salivary duct carcinoma are described. This relatively rare tumour, which only recently has been widely recognized as a separate entity, is highly malignant and caused the death in eight of the patients. The tumour cells are arranged in cribriform and solid growth patterns, where the solid tumour nests frequently have comedo necrosis, and a fibrous, often sclerotic, stroma is present. The infiltrating desmoplasmic component and the diffuse invasive growth into adjacent adipose parotid tissue have similarities to ductal breast carcinoma. Immunocytochemical investigation of salivary duct carcinoma showed constant overexpression of c-erbB-2 as detected by membrane accentuation, and high proliferative activity as detected by nuclear positivity for MIB 1 (Ki-67). Changes in the expression of p53 and retinoblastoma gene product do not constitute a constant event in salivary duct carcinoma. A few of the tumours showed scattered cells with distinct nuclear positivity for both progesterone and oestrogen receptors. We emphasize that this highly malignant salivary gland tumour has a characteristic morphology, may not be as rare as previously considered, and that prompt and aggressive therapy is needed.
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| 7. |
- Hughes, Francine MR, et al.
(författare)
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The influence of hydrological regimes on sex ratios and spatial segregation of the sexes in two dioecious riparian shrub species in northern Sweden
- 2010
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Ingår i: Plant Ecology. - : Springer Science and Business Media LLC. - 1385-0237 .- 1573-5052. ; 208:1, s. 77-92
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Tidskriftsartikel (refereegranskat)abstract
- River management practices have altered the hydrological regimes of many rivers and also altered the availability of regeneration niches for riparian species. We investigated the impact of changed hydrological regimes on the sex ratios and the Spatial Segregation of the Sexes (SSS) in the dioecious species Salix myrsinifolia Salisb.–phylicifolia L. and S. lapponum L. by studying the free-flowing Vindel River and the regulated Ume River in northern Sweden. We surveyed sex ratios of these species in 12 river reaches on the Vindel River and in 17 reaches on the Ume River. In addition, we surveyed the sex and location above mean river stage of 1,002 individuals across both river systems to investigate the SSS of both species. Cuttings were collected from male and female individuals of S. myrsinifolia–phylicifolia from both rivers and subjected to four different water table regimes in a greenhouse experiment to investigate growth response between the sexes. We found an M/F sex ratio in both river systems similar to the regional norm of 0.62 for S.myrsinifolia–phylicifolia and of 0.42 for S. lapponum. We found no evidence of SSS in either the free-flowing Vindel River or the regulated Ume River. In the greenhouse experiment, hydrological regime had a significant effect on shoot and root dry weight and on root length. Significantly higher shoot dry weights were found in females than in males and significantly different shoot and root dry weights were found between cuttings taken from the two rivers. We concluded that changed hydrological regimes are likely to alter dimensions of the regeneration niche and therefore to influence sex ratios and SSS at an early successional stage, making it difficult to find clear spatial patterns once these species reach maturity and can be sexed.
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| 9. |
- Hylander, Kristoffer, et al.
(författare)
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Substrate form determines the fate of bryophytes in clear-cuts and buffer strips along small boreal streams
- 2005
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Ingår i: Ecological Applications. - : Wiley. - 1051-0761. ; 15:2, s. 674-688
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Tidskriftsartikel (refereegranskat)abstract
- Studies on the effectiveness of forest buffer strips left along streams after logging have long overlooked the biota of the buffers themselves, despite their high species richness. We investigated mosses and liverworts (bryophytes), abundant and species-rich groups in boreal forests, before and 2.5 years after logging along 15 small streams. In each Site, two 1000-m(2) (20 X 50 m) plots along the stream were inventoried; one plot in an area subjected to clear-cutting, and another in a buffer strip (10 m wide on each side of the stream). Ten plots along small streams in forest reserves in the same region were used as references. We found that less than half as many bryophyte species per plot disappeared after logging in the buffer strips compared to the clearcuts. The changes in bryophyte cover and in species composition were smaller in the buffer strips, and the species that were negatively affected in the clearcuts were less affected in the buffer strips. However, there was a significant change in species composition in the buffer strips compared to the references. Substrate form. and taxonomic group were important factors in understanding this turnover. Many species growing on substrates with a convex form (e.g., logs, tree bases, and mesic ground) decreased or disappeared, while species on concave substrates were rather unaffected. This held for both mosses and liverworts, although liverworts were generally more sensitive than mosses. The difference in response of assemblages on convex vs. concave substrates makes changes in microclimate due to logging a likely explanation. The species in most need of protection (i.e., the red-listed species) were among the ones with strongest declines in the 20 m wide buffer strips. In order to function optimally for bryophyte conservation, forests along small streams need to be protected from high wind-throw frequency and strong edge effects. Increasing the width of buffer strips at sites with known or potential values (e.g., large amounts of woody debris or boulders) should be considered a better strategy than using narrow buffer strips with a fixed width.
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