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Central Sweden (central + sweden)
Selected AbstractsDemo-genetic analysis of a recovering population of otters in Central SwedenANIMAL CONSERVATION, Issue 6 2008M. Björklund Abstract We performed a demo-genetic population viability analysis on a recovering population of otters Lutra lutra in Central Sweden, using data on population size, survival and genetic data from microsatellites. Population data were obtained from genotyping faeces. At present, the size and genetic variability of the population is increasing. We found that survival to first reproduction was the most crucial demographic parameter, and that even slight changes downward in this parameter, might lead to a declining population trajectory. Human factors that can affect mortality are traffic, fishing equipment and traps, and we argue that efforts to minimize road kills by means of safe passages as well as careful fishing efforts in streams and lakes would reduce the risk of extinction. In general, even though the population is now growing and has no inbreeding problem, its small abundance could make it vulnerable to chance events and environmental perturbations. [source] Climatic adaptation in an isolated and genetically impoverished amphibian populationECOGRAPHY, Issue 4 2010Germán Orizaola The capacity of populations to respond adaptively to environmental change is essential for their persistence. Isolated populations often harbour reduced genetic variation, which is predicted to decrease adaptive potential, and can be detrimental under the current scenarios of global change. In this study, we examined climatic adaptation in larval life history traits in the pool frog Rana lessonae along a latitudinal gradient across the northern distribution area of the species, paying special attention to the isolated and genetically impoverished fringe populations in central Sweden. Larvae from eight populations within three geographic areas (Poland, Latvia and Sweden) were reared under three temperatures (19, 22 and 26°C) in a common garden laboratory experiment. We found clear evidence for latitudinal adaptation in R. lessonae populations, larvae from higher latitudes growing and developing faster than low-latitude ones. Larvae from the Swedish populations were able to compensate for the effects of cooler temperatures and a shorter growth season with genetically higher growth and development rates (i.e. countergradient variation) in the two higher temperature treatments, but there was no difference among the populations at the lowest temperature treatment, which is likely to be close to the temperature limiting growth in R. lessonae. Our results demonstrate that isolated and genetically impoverished populations can be locally adapted, and identify the Swedish fringe populations as a significant conservation unit adapted to the northern environmental conditions. [source] Habitat selection and reproductive success of Ortolan Buntings Emberiza hortulana on farmland in central Sweden , the importance of habitat heterogeneityIBIS, Issue 3 2008ÅKE BERG Many granivorous birds have shown severe population declines in Europe during recent decades. The aim of the present study was to analyse habitat preferences and reproductive success of one such species, the Ortolan Bunting Emberiza hortulana, in different farmland habitats in south-central Sweden. Four seemingly different land-use types were preferred: permanent set-asides, short rotation coppice, and grazed and unmanaged semi-natural pastures. Territories and random sites differed considerably in the proportion of these preferred land-use types; 39% of territories had > 70% preferred habitat (at the 100-m scale) compared to 5% of random sites. In contrast, 22% of territories and 65% of random sites had no preferred habitats. All the preferred habitats had heterogeneous ground vegetation characterized by patches with bare ground, or at least sparse ground vegetation, intermixed with patches with taller vegetation. Ortolan Buntings also preferred a heterogeneous habitat structure with occurrence of field islets, shrubby edges, barns and electric wires, which could act as song posts or suitable nest-sites, in 88% of territories. At a larger (1-km square) scale, territories occupied by pairs aggregated strongly in areas with high proportions of preferred habitats. The number of territories with single males correlated positively with the number of pairs, which suggests that conspecific attraction may influence territory distribution. No measured habitat factors were related to reproductive success. However, due to habitat preferences and the higher proportion of paired males in one habitat type (set-aside), the production of young (fledglings/ha) is expected to be higher in set-asides, as well as in short-rotation coppices and semi-natural pastures. Thus, these habitats are important for the conservation of the Ortolan Bunting. Large areas with habitat structures such as field islets are especially important because the Ortolan Bunting breeds in aggregations in these areas. [source] Population dynamics and reproduction of Northern Lapwings Vanellus vanellus in a meadow restoration area in central SwedenIBIS, Issue 3 2002Åke Berg To investigate the effectiveness of a meadow restoration programme, we studied the relationships between population changes and environmental changes, return rates and hatching success in a population of Northern Lapwings Vanellus vanellus. The study was performed on mixed farmland (59 km2) in central Sweden, an area that underwent extensive meadow restoration between 1985 and 1994. The study included more than 2600 nests, supplemented with observations of 127 individually colour-ringed Northern Lapwings. The breeding population varied (2.7,5.3 pairs/km2), but showed no significant trend with time. The population increased in years with high spring flooding levels. Population size was unrelated to demographic factors (e.g. hatching success the previous year (14,50%), and return rate). Lapwings moved considerably between years and their nest site fidelity was unrelated to previous hatching success or other factors, suggesting that changes in habitat quality and migration between populations were important in regulating population size. Recent extensive meadow restoration did not seem to aid the Northern Lapwing population; birds continued nesting on tillage even though most nests were destroyed by farming activities. A relatively high relaying frequency improved hatching success, which was still lowest in the most preferred habitats (spring sown crops, total hatching success c. 30%). The few Northern Lapwings breeding in the least preferred habitats (meadows and cultivated grassland) had a better hatching success (> 70% total hatching success), suggesting that habitat selection was not determined by hatching success. From these results, recommendations are made for the management of Northern Lapwing (and associated species) populations on farmland. [source] Modeling an industrial energy system: Perspectives on regional heat cooperationINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 9 2008S. Klugman Abstract Through energy efficiency measures, it is possible to reduce heat surplus in the pulp and paper industry. Yet pulp and paper mills situated in countries with a heat demand for residential and commercial buildings for the major part of the year are potential heat suppliers. However, striving to utilize the heat within the mills for efficient energy use could conflict with the delivery of excess heat to a district heating system. As part of a project to optimize a regional energy system, a sulfate pulp mill situated in central Sweden is analyzed, focusing on providing heat and electricity to the mill and its surrounding energy systems. An energy system optimization method based on mixed integer linear programming is used for studying energy system measures on an aggregated level. An extended system, where the mill is integrated in a regional heat market (HM), is evaluated in parallel with the present system. The use of either hot sewage or a heat pump for heat deliveries is analyzed along with process integration measures. The benefits of adding a condensing unit to the back-pressure steam turbine are also investigated. The results show that the use of hot sewage or a heat pump for heat deliveries is beneficial only in combination with extended heat deliveries to an HM. Process integration measures are beneficial and even increase the benefit of selling more heat for district heating. Adding a condensing turbine unit is most beneficial in combination with extended heat deliveries and process integration. Copyright © 2007 John Wiley & Sons, Ltd. [source] Implementing a pre-operative checklist to increase patient safety: a 1-year follow-up of personnel attitudesACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 2 2010L. NILSSON Background: The operating room is a complex work environment with a high potential for adverse events. Protocols for perioperative verification processes have increasingly been recommended by professional organizations during the last few years. We assessed personnel attitudes to a pre-operative checklist (,time out') immediately before start of the operative procedure. Methods: ,Time out' was implemented in December 2007 as an additional safety barrier in two Swedish hospitals. One year later, in order to assess how the checklist was perceived, a questionnaire was sent by e-mail to 704 persons in the operating departments, including surgeons, anesthesiologists, operation and anesthetic nurses and nurse assistants. In order to identify differences in response between professions, each alternative in the questionnaire was assigned a numerical value. Results: The questionnaire was answered by 331 (47%) persons and 93% responded that ,time out' contributes to increased patient safety. Eighty-six percent thought that ,time out' gave an opportunity to identify and solve problems. Confirmation of patient identity, correct procedure, correct side and checking of allergies or contagious diseases were considered ,very important' by 78,84% of the responders. Attitudes to checking of patient positioning, allergies and review of potential critical moments were positive but differed significantly between the professions. Attitudes to a similar checklist at the end of surgery were positive and 72,99% agreed to the different elements. Conclusion: Staff attitudes toward a surgical checklist were mostly positive 1 year after their introduction in two large hospitals in central Sweden. [source] Effects of ultraviolet-B radiation and pH on early development of the moor frog Rana arvalisJOURNAL OF APPLIED ECOLOGY, Issue 3 2001Maarit Pahkala Summary 1,Although the potential negative effects of increased ultraviolet-B (UV-B) radiation on early life stages of aquatic organisms are widely recognized, possible synergistic effects with other stressors have seldom been studied outside the laboratory. We investigated the effects of UV-B radiation and pH on hatchability and early development of moor frog Rana arvalis eggs in the field and in laboratory experiments conducted during April 1998 and April 2000 in central Sweden. 2,In the field experiments, no evidence was found for reduced hatchability or increased frequency of developmental anomalies of embryos exposed to ambient levels of UV-B compared with embryos shielded from UV-B radiation. 3,Hatchlings shielded from ambient UV-B radiation did not grow larger than their exposed full-sibs, giving no support to the hypotheses that (i) the repair of cellular UV-B damage might be energetically costly nor (ii) that UV-B-induced photoproducts directly reduce growth. 4,Although low pH (5·0) reduced hatchability, increased frequency of developmental anomalies and reduced early embryonic growth in R. arvalis, there was no evidence for synergistic effects of pH and UV-B on any of these traits. 5,The lack of UV-B radiation effects on the development of R. arvalis embryos cannot be ascribed to relatively low effective daily doses of radiation (c. 0·43 kJ m,2) during the field experiments, as in the laboratory even higher doses at UV-B 1·25 kJ m,2 and 1·58 kJ m,2 (all DNA weighed) had no negative effects. 6,These results suggest that current levels of UV-B radiation in northern Europe are not likely to reduce fitness in natural populations of the moor frog, even in areas already stressed by acidity. [source] The effect of past changes in inter-annual temperature variability on tree distribution limitsJOURNAL OF BIOGEOGRAPHY, Issue 7 2010Thomas Giesecke Abstract Aim, The northern limits of temperate broadleaved species in Fennoscanndia are controlled by their requirements for summer warmth for successful regeneration and growth as well as by the detrimental effects of winter cold on plant tissue. However, occurrences of meteorological conditions with detrimental effects on individual species are rare events rather than a reflection of average conditions. We explore the effect of changes in inter-annual temperature variability on the abundances of the tree species Tilia cordata, Quercus robur and Ulmus glabra near their distribution limits using a process-based model of ecosystem dynamics. Location, A site in central Sweden and a site in southern Finland were used as examples for the ecotone between boreal and temperate forests in Fennoscandia. The Finnish site was selected because of the availability of varve-thickness data. Methods, The dynamic vegetation model LPJ-GUESS was run with four scenarios of inter-annual temperature forcing for the last 10,000 years. In one scenario the variability in the thickness of summer and winter varves from the annually laminated lake in Finland was used as a proxy for past inter-annual temperature variability. Two scenarios were devised to explore systematically the effect of stepwise changes in the variance and shape parameter of a probability distribution. All variability scenarios were run both with and without the long-term trend in Holocene temperature change predicted by an atmospheric general circulation model. Results, Directional changes in inter-annual temperature variability have significant effects on simulated tree distribution limits through time. Variations in inter-annual temperature variability alone are shown to alter vegetation composition by magnitudes similar to the magnitude of changes driven by variation in mean temperatures. Main conclusions, The varve data indicate that inter-annual climate variability has changed in the past. The model results show that past changes in species abundance can be explained by changes in the inter-annual variability of climate parameters as well as by mean climate. Because inter-annual climatic variability is predicted to change in the future, this component of climate change should be taken into account both when making projections of future plant distributions and when interpreting vegetation history. [source] Large-scale geographical trends in fruit traits of vertebrate-dispersed temperate plantsJOURNAL OF BIOGEOGRAPHY, Issue 4 2003Arndt Hampe Abstract Aim, To assess large-scale geographical trends in the character of fleshy, vertebrate-dispersed fruits. Location, Europe between central Sweden and southern Spain. Methods, Analyses of fruit of sixty-three plant species from twenty-nine families were compiled from four regional data sets. Four structural and five chemical fruit traits were analysed intraspecifically to control rigorously for phylogenetic lineage effects. Trends were examined in relation to various biological features of the considered species. Results, Contents of soluble carbohydrate and lipids decreased markedly northwards. Fruit diameter and fresh mass peaked at the wettest site, while the pulp water content remained more constant throughout the gradient than any other fruit trait. Ash content, seed number and seed mass did not change, while the nitrogen content showed conflicting trends. No relation was detected between observed variation in fruit traits and fruit type, fruit colour, ripening season, plant growth form, leaf longevity, or geographical distribution of the considered plant species. Main conclusions, Considerable intraspecific variability exists in vertebrate-dispersed fruits on large geographical scales. Climate presumably affects particularly those traits related to carbon and water gain and storage. Most research on fruit,frugivore interactions has been carried out on small spatial scales and failed to find matchings between frugivore communities and the character of fleshy fruits. I suggest that explicitly addressed large-scale surveys on the geographical variability of fruits and their disperser assemblages are needed to elucidate their spatial patterns and to determine the extent to which fleshy fruit traits are shaped by animals and/or abiotic factors. [source] The risk of ipsilateral versus contralateral recurrent deep vein thrombosis in the legJOURNAL OF INTERNAL MEDICINE, Issue 5 2000P. Lindmarker Abstract. Lindmarker P, Schulman S, the DURAC Trial Study Group (Karolinska Hospital, Karolinska Institute, Stockholm, Sweden) The risk of ipsilateral versus contralateral recurrent deep vein thrombosis in the leg. J Intern Med 2000; 247: 601,606. Objectives. To investigate the risk of ipsilateral versus contralateral recurrent deep vein thrombosis in the leg. Design. An open prospective long term follow-up multicentre trial. Patients were followed by frequent outpatient visits at each centre during the first 12 months after inclusion and thereafter annually. Setting. Sixteen hospitals in central Sweden. Subjects. A total of 790 consecutive patients with objectively verified first episode of acute deep vein thrombosis and without diagnosed malignant disease were recruited from a randomized study comparing 6 weeks with 6 months of oral antivitamin K therapy as secondary thromboprophylaxis. Main outcome measures. Deep vein thrombosis in the contralateral leg was confirmed by venography or ultrasound. With regard to the ipsilateral leg, venography was required. Results. A recurrent episode of venous thromboembolism was documented in 192 patients after a mean (±SD) period of 31(±29) months. In 26 additional patients with ipsilateral symptoms the diagnostic critera were not fulfilled. One hundred and eleven patients have deceased and 69 patients withdrew from the study. The 392 patients without recurrent episodes were followed for a median of 96 months with 90% for at least 48 months. An objectively verified recurrent contralateral and ipsilateral deep vein thrombosis occurred in 95 and 54 cases, respectively, and in 41 patients pulmonary embolism was documented. In two patients thromboses with unusual locations were registered. The risk of contralateral versus ipsilateral recurrence was significantly increased with a risk ratio of 1.6 (95% confidence interval 1.4,1.9) in a time to event model. In a multivariate analysis none of the investigated variables were significantly associated with the side of recurrent thrombosis. Conclusions. The risk of a recurrent deep vein thrombosis is increased in the contralateral leg. This brings into question the importance of an impaired venous flow for recurrent episodes of thrombosis. [source] Quantitative palaeotemperature records inferred from fossil pollen and chironomid assemblages from Lake Gilltjärnen, northern central Sweden,JOURNAL OF QUATERNARY SCIENCE, Issue 8 2006Karin Antonsson Abstract Palaeotemperature reconstructions based on radiocarbon-dated fossil pollen and chironomid stratigraphies obtained from Lake Gilltjärnen provide evidence of climate changes during the last 11,000 years in the boreal zone of northern central Sweden. The records show consistent trends during the early and mid-Holocene, indicating low temperatures at 11,000,10,000,cal.,yr,BP, followed by a rising trend and a period of maximum values from about 7000 to 4000,cal.,yr,BP. At 3000,cal.,yr,BP the chironomid-inferred temperature values rise abruptly, deviating from the late-Holocene cooling trend indicated by the pollen-based reconstruction and most of the other palaeotemperature records from central Scandinavia, probably as a result of local limnological changes in Lake Gilltjärnen and its catchment. Comparison of the present results with a lake-level reconstruction from Lake Ljustjärnen, ca. 100,km southwest of Lake Gilltjärnen, shows that the low early-Holocene temperatures were associated with high lake-levels at 10,500,8500,cal.,yr,BP, whereas low lake-levels and dry conditions prevailed during the period of high temperatures at between 7500 and 5000,cal.,yr,BP, probably due to high summer evapotranspiration and lower precipitation. Copyright © 2006 John Wiley & Sons, Ltd. [source] Towards a Holocene tephrochronology for Sweden: geochemistry and correlation with the North Atlantic tephra stratigraphyJOURNAL OF QUATERNARY SCIENCE, Issue 2 2004Jane Boygle Abstract Northern Europe has been affected by fallout of tephra from volcanic eruptions in Iceland throughout at least the Late-glacial and Holocene. Microscopic volcanic ash horizons found in the British Isles, northern Germany and Scandinavia (e.g. Hekla 4) now provide important regional isochrons. Over recent years analytical techniques such as electron probe microanalysis (EPMA) have helped identify these distal tephra layers by glass geochemistry. Early tephra work in Sweden used refractive indices and bracketing radiocarbon dates for identification, resulting in tentative correlation. This paper presents geochemical data for Icelandic Holocene tephra in Sweden. Several sites in central Sweden have four distinct mid-Holocene tephra layers. Correlation with the Icelandic record indicates that the following tephra layers are present: Hekla 4 (ca. 3830,yr,BP), Kebister tephra (ca. 3600,yr,BP), Hekla 3 (ca. 2880,yr,BP) and Askja ad 1875. Preliminary analyses suggest that more, previously unidentified, tephra layers are present in low concentrations in the region, indicating potential for expanding the Swedish tephrochronology for palaeoecological and palaeoenvironmental work in northern Europe. Copyright © 2004 John Wiley & Sons, Ltd. [source] On Hieracium incurrens (Asteraceae) and similar species in central SwedenNORDIC JOURNAL OF BOTANY, Issue 3-4 2007Torbjörn Tyler Hieracium incurrens Saelan ex Norrl., originally described from Finland, has been reported from Sweden several times and independently by different authors. Still, however, its presence in Sweden has remained dubious and it has become obvious that the different reports are referable to different taxa and the name has thus been, at least partially, misapplied. In the present study, all Swedish material and putative taxa that have been suggested to belong to H. incurrens, as well as some additional closely similar taxa, is critically compared with authentic material of the latter from Finland. It is concluded that H. incurrens do indeed occur in central Sweden, namely in the eastern coastal provinces closest to Finland. However, the relevant material has mostly been referred to H. longilingua Johanss., which is here considered to be a later synonym of H. incurrens. Material previously referred to H. incurrens from other parts of Sweden does, however, represent other taxa. Five accepted species of this affinity are described and discussed in some detail and one species, viz. H. oestmanii T. Tyler is described anew. In addition, the unrelated species H. arnoldii T. Tyler is described anew based on material from the provinces of Hälsingland and Medelpad. [source] An analysis of hatching success in the great reed warbler Acrocephalus arundinaceusOIKOS, Issue 3 2008Jonas Knape Hatching success is a potentially important fitness component for avian species. Previous studies of hatching success in natural populations have primarily focused on effects of inbreeding but a general understanding of variation in hatching success is lacking. We analyse data on hatching success in a population of great reed warblers Acrocephalus arundinaceus in Lake Kvismaren in south central Sweden. The effects of a range of covariates, including three measures of inbreeding as well as effects of classifications in the data (such as identities of individuals), on hatching success are analysed simultaneously. This is done by means of fitting Bayesian binomial mixed models using Markov chain Monte Carlo methods. Using random effects for each individual parent we check for unexplained variation in hatching success among male and female individuals and compare it to effects of covariates such as degree of inbreeding. Model selection showed that there was a significant amount of unexplained variation in hatching probability between females. This was manifested by a few females laying eggs with a substantially lower hatching success than the majority of the females. The deviations were of the same order of magnitude as the significant effect of parent relatedness on hatching success. Whereas the negative effect of parent relatedness on hatchability is an expression of inbreeding, the female individual effect is not due to inbreeding and could reflect maternal effects, that females differ in fertilisation and/or incubation ability, or an over representation of genetic components from the female acting on the early developing embryo. [source] THE LOWER CAMBRIAN EODISCOID TRILOBITE CALODISCUS LOBATUS FROM SWEDEN: MORPHOLOGY, ONTOGENY AND DISTRIBUTIONPALAEONTOLOGY, Issue 3 2009PETER CEDERSTRÖM Abstract:, Several thousand disarticulated remains together with a few complete enrolled specimens of the lower Cambrian eodiscoid trilobite Calodiscus lobatus (Hall, 1847) have been collected at two outcrop areas in Sweden. The material reveals new details of morphology and morphogenesis during ontogenetic development. Size-frequency analyses show that the material from the Fånån rivulet in Jämtland, central Sweden, represents a natural population dominated by juveniles, whereas the material from Gislövshammar in Scania, southern Sweden, has been sorted during postmortem transport. Three stages of protaspid development can be traced and defined as well as all subsequent ontogenetic stages for the cephalon, hypostome and pygidium. The early meraspid pygidium has a pronounced larval notch, which persists, though becoming progressively less distinct in later meraspides. The number of axial rings in the transitory pygidium increases throughout meraspid development until a third and final thoracic segment is liberated. During ontogeny the articulating half-rings are strongly developed, and both meraspides and holaspides were capable of full sphaeroidal enrollment and outstretched postures. The hypostome undergoes some dramatic modifications; in M0 the anterior margin is axe-shaped, by M1 the area of attachment greatly decreases and the hypostome becomes more elongated and pear-shaped, before attaining its adult form, which has an overall resemblance to that of polymerid trilobites. During ontogeny, the hypostome changes from a conterminant attachment to a natant condition, thereby mirroring hypostomal evolution within trilobites generally. The morphology, ontogeny, enrollment, hypostomal development and the presence of calcified protaspides suggest polymerid rather than agnostoid affinities of the eodiscoids. [source] Remnant habitats for grassland species in an abandoned Swedish agricultural landscapeAPPLIED VEGETATION SCIENCE, Issue 3 2010Anna Dahlström Abstract Questions: Which factors influence the persistence of vascular grassland plants in long-abandoned (at least 50 yr) arable fields and meadows? What might be the implications of current levels of species richness on abandoned arable fields and meadows for future restoration? Location: Forested highlands of Kilsbergen, south central Sweden. Methods: The abundance of all vascular plant species was investigated in three habitat types: former arable fields, hay meadows and outlands (pastures) at 27 farms, abandoned for either approximately 50 yr or 90 yr. Time since abandonment, tree cover, soil depth, degree of soil podsol development, size of the infield area and two measures of connectivity were used as predictors for species richness and species composition. Results: Former outland had denser tree cover, fewer species and fewer grassland species than former arable fields and hay meadows, irrespective of time since abandonment. Former hay meadows and arable fields with a longer time since abandonment were less rich in species, more wooded and had greater podsolization than meadows and fields abandoned at a later stage. Species richness was higher in hay meadows and arable fields at farms with larger infield area and deeper soils compared with farms with smaller infield area and shallower soils. The greatest richness of species and most open habitat were former arable fields at larger farms abandoned 50 yr before the study. Former arable fields had the highest number of grassland species. Conclusion: After 50 yr of abandonment, former arable fields were the most important remnant habitats for grassland species and may be a more promising target for restoration than formerly managed grasslands. [source] Effects on vegetation composition of a modified forest harvesting and propagation method compared with clear-cutting, scarification and plantingAPPLIED VEGETATION SCIENCE, Issue 2 2008Johan Bergstedt Question: How does the vegetation of boreal forests respond to harvesting and scarification? Location: 650 m a.s.l., central Sweden (61°38' N). Methods: The response of boreal forest vegetation to cutting and scarification was studied in a field trial, which consisted of three treatments plus conventional harvesting as a control in a complete block design with four replicates. The cutting was done 14 years prior to vegetation inventory and scarification and planting were conducted the first or second years after cutting. Results: The species most abundant at higher cutting intensities were crustose lichens, Cladonia spp., Cladina arbuscula, Polytrichum spp. and pioneer mosses, the grass Deschampsia flexuosa, and the tree Betula pubescens, A few species had substantially lower abundance in treatments with higher cutting intensity, notably Hylocomium splendens and Vaccinium myrtillus. Scarification had a strong effect that was different from the one created by cutting. In scarification treatments, Polytrichum spp. were the only species with high abundance; most species had low abundance, i.e. Barbilophozia lycopodioides, Vaccinium vitis-idaea, Pleurozium schreberi, Carex globularis, Empetrum nigrum, Cladina arbuscula, Sphagnum spp. Conclusions: Our results elaborate on the details of the well-known effect of cutting on ground-layer flora, and also give support for the profound and long-lasting effect that soil scarification has on forest vegetation. [source] Pseudoexfoliation as a risk factor for prevalent open-angle glaucomaACTA OPHTHALMOLOGICA, Issue 7 2008Curt Ekström Abstract. Purpose:, To estimate the risk of open-angle glaucoma (OAG) associated with exposure to pseudoexfoliation (PEX) and increased intraocular pressure (IOP). Methods:, In 1984,86, a cross-sectional, population-based survey was conducted in the municipality of Tierp, central Sweden. Its target population comprised 2429 residents aged 65,74 years. In addition to a sample of 760 people, patients previously diagnosed with glaucoma were examined. The prevalence of OAG in the target population was estimated from the prevalence in the sample and patients already diagnosed. A review of prevalent cases in 1984,86 was undertaken in 2006. Results:, Definite OAG was established in 77 cases, corresponding to a prevalence of 5.3% (95% confidence interval [CI] 4.4,6.2). Of these, 23 represented newly detected cases. The prevalence of PEX was 17.2% (95% CI 14.6,19.9), calculated from 134 cases in the population sample. When adjusting for gender, PEX was associated with a 4.7-fold (95% CI 2.2,9.4) increased risk of OAG. For clinical cases only, the risk was 16-fold (95% CI 4.8,56) greater in subjects with PEX, compared with those without PEX. In individuals without a previous diagnosis of glaucoma, an IOP , 20 mmHg was associated with a 9.7-fold (95% CI 3.7,27) increased risk, but PEX alone was not a risk factor for OAG (adjusted odds ratio = 0.96). Conclusions:, Pseudoexfoliation was associated with OAG only in people previously diagnosed with the disease. In cases detected in the population-based survey, increased IOP was a serious risk factor. [source] Incidence of open-angle glaucoma in central SwedenACTA OPHTHALMOLOGICA, Issue 7 2008Curt Ekström Abstract. Purpose:, To estimate the incidence rate of open-angle glaucoma (OAG) in a population in which pseudoexfoliation is a common finding. Methods:, A population-based survey of 760 people aged 65,74 years was conducted in the municipality of Tierp, in central Sweden, during 1984,86. Visual fields (VFs) were tested with the Competer 350 automated perimeter. The present report concerns 711 people, all of whom participated in the survey and were not diagnosed with glaucoma. Since 1988, a follow-up study of the 530 individuals in this cohort with normal and reliable VFs has been in progress. Incident cases of OAG were identified among study participants and patients seeking medical attention at the Eye Department in Tierp. Records of prescriptions for anti-glaucoma drugs were used to search for unidentified patients. A time-weighted mean intraocular pressure (IOP) for all visits was calculated. Results:, By the end of the study in May 2006, 51 new cases of definite OAG had been identified, 31 with capsular and 20 with chronic simple glaucoma. Of these, 46 cases were detected in the follow-up study, corresponding to an incidence of 7.11 (95% confidence interval 5.06,9.17) per 1000 person-years. Twelve of the 51 cases were classified as normal-tension glaucoma, all of which were found in the follow-up study. Open-angle glaucoma with a mean IOP , 23 mmHg tended to emerge closer to the baseline examination than OAG with a mean IOP < 23 mmHg. Conclusions:, The incidence of OAG was high compared with that reported for other studies conducted in White populations. [source] | |||||||||||||||||||