| 1. |
- Archer, Trevor, 1949, et al.
(författare)
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Effects of physical exercise on depressive symptoms and biomarkers in depression
- 2014
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Ingår i: CNS & Neurological Disorders. - Bussum : Bentham Science Publishers. - 1871-5273 .- 1996-3181. ; 13:10, s. 1640-1653
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Tidskriftsartikel (refereegranskat)abstract
- Regular physical exercise/activity has been shown repeatedly to promote positive benefits in cognitive, emotional and motor domains concomitant with reductions in distress and negative affect. It exerts a preventative role in anxiety and depressive states and facilitates psychological well-being in both adolescents and adults. Not least, several meta-analyses attest to improvements brought about by exercise. In the present treatise, the beneficial effects of exercise upon cognitive, executive function and working memory, emotional, self-esteem and depressed mood, motivational, anhedonia and psychomotor retardation, and somatic/physical, sleep disturbances and chronic aches and pains, categories of depression are discussed. Concurrently, the amelioration of several biomarkers associated with depressive states: hypothalamic-pituitary-adrenal (HPA) axis homeostasis, anti-neurodegenerative effects, monoamine metabolism regulation and neuroimmune functioning. The notion that physical exercise may function as "scaffolding" that buttresses available network circuits, anti-inflammatory defences and neuroreparative processes, e.g. brain-derived neurotrophic factor (BDNF), holds a certain appeal. © 2014 Bentham Science Publishers.
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| 2. |
- Atiwi, N., et al.
(författare)
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Analysis and Performance of High Voltage DC Power Supplies Used for Low Current Measurements on Dielectric Materials
- 2014
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Ingår i: Conference on Electrical Insulation and Dielectric Phenomena Annual Report, 2014 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP), Des Moines, IA. - 0084-9162. - 9781479975259 ; , s. 590-593
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Konferensbidrag (refereegranskat)abstract
- Characterization of the conductive current associated with XLPE, found in power cables requires HVDC power supplies with very stable voltage output. The very low conductivity has led to an increased need of a more accurate measurement technique to characterize the conductive parts of dielectric materials. Commercial HVDC power supplies used for such measurements do not provide a pure DC due to the power electronics that contribute to a high frequency component which in return generates a capacitive current. The generated capacitive current can be difficult to differentiate with the actual measurement of the conductive current. In order to achieve measurements of the conductive current, the influence of the generated capacitive current must be sufficiently lower than the conductive current. By designing a power supply with low ripple generation, the influence of the capacitive current can be diminished. A ripple and harmonic free HVDC power supply consisting of 1 kV battery pack was therefore developed to examine the impact of the high frequency component of commercial HVDC power supplies.
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| 3. |
- Back, Jenny, 1984-, et al.
(författare)
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Psychological risk factors for exercise dependence
- 2021
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Ingår i: International Journal of Sport and Exercise Psychology. - New York : Routledge. - 1612-197X .- 1557-251X. ; 19:4, s. 461-472
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Tidskriftsartikel (refereegranskat)abstract
- The main aim of this study was to investigate if exercisers' personality characteristics were associated with exercise dependence. Specifically, the purpose was to examine if anxiety, obsessive passion, and physical appearance orientation were associated to an increased risk for exercise dependence. Participants were 330 exercisers from exercise groups, sport clubs and university sport science classes in the southwest of Sweden. Data were analysed using CHAID (Chi-squared Automatic Interaction Detection) analysis. The CHAID analysis indicated that anxiety was the main predictor of exercise dependence. More specifically, 12.7% more exercisers who experienced high levels of anxiety symptoms (i.e. scores above 6), were, in comparison to the exercises experiencing low levels of anxiety, classified as ?at risk for exercise dependence?. For exercisers that reported low levels of anxiety symptoms (i.e. scores below 7), obsessive passion for exercise was a positive statistically significant predictor (absolute risk difference?=?8.6%). Overall, the results highlight anxiety as a main risk factor behind exercise dependence. Also, the risk of exercise dependence may increase either from obsessive passion or as a coping strategy for anxiety. Furthermore, results may illustrate two types of exercise dependence; ?primary? exercise dependence driven mainly by an obsessive passion for exercise and ?secondary? exercise dependence where exercise function as a strategy to cope with anxiety.
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| 4. |
- Baudet, Marlène, et al.
(författare)
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New insights into estimating the age of old Scots pine from increment cores with stem rot
- 2020
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Ingår i: Dendrochronologia. - : Elsevier BV. - 1125-7865. ; 64
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Tidskriftsartikel (refereegranskat)abstract
- Trunk inner rot is a common phenomenon in some old-growth pine dominated forests, making it impossible to determine tree age by counting annual rings. We compared the efficiency of five methods to estimate the age of hollow pine trees (Pinus sylvestris L.). Our main aims were to select the best-performing method and to test whether the age of the tree or the proportion of rot influences the accuracy of estimation. We used full increment cores (reaching the pith or within 1 cm of it) from 100 trees (54-562 years old) collected in northern Sweden and simulated rotten centres of three different sizes in order to test the methods. The lowest error rates were obtained when less than a third of the sample was missing (down to 5.0 % error rate), and by using a method based on the growth pattern of a set of healthy trees. Using linear extrapolation of the mean radial growth led to large overestimates (up to three times the number of absent rings) with error rates up to 27.3 %. We also found that the performance of all methods was reduced in cores from older trees. Our main conclusion is that non-linear methods should be preferred for age estimation of hollow pines. We also argue that more precision in the age estimation could be gained already in the field by collecting multiple cores from rotten trees or by developing alternative coring methods.
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| 5. |
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| 6. |
- Björklund, Jesper, 1979, et al.
(författare)
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Advances towards improved low-frequency tree-ring reconstructions, using an updated Pinus sylvestris L. MXD network from the Scandinavian Mountains
- 2013
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Ingår i: Journal of Theoretical and Applied Climatology. - : Springer Science and Business Media LLC. - 0177-798X .- 1434-4483. ; 113:3-4, s. 697-710
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Tidskriftsartikel (refereegranskat)abstract
- The dendrochronological use of the parameter maximum density (MXD) in Pinus Sylvestris L., at high latitudes, has provided valuable insights into past summer temperature variations. Few long MXD chronologies, from climatically coherent regions, exist today, with the exception being in northern Europe. Five, 500-year-long, Fennoscandian, MXD chronologies were compared with regard to their common variability and climate sensitivity. They were used to test Signal-free standardization techniques, to improve inferences of low-frequency temperature variations. Climate analysis showed that, in accordance with previous studies on MXD in Fennoscandia, the summer temperature signal is robust (R (2) > 50 %) and reliable over this climatically coherent region. A combination of Individual standardization and regional curve standardization is recommended to refine long-term variability from these MXD chronologies and relieve problems arising from low replication and standardization end-effects.
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| 7. |
- Brechensbauer Brandin, Madeleine, et al.
(författare)
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Centralen : Studier i området kring Stockholms Centralstation
- 1989
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Rapport (populärvet., debatt m.m.)abstract
- Denna skrift handlar om Centralen i Stockholm och dess närmaste omgivningar, Centralplan, T-centralen, Vasagatan och Klarabergsgatan. Den är resultatet av Arkitekturskolans arbete läsåret 1983- 84 och innehåller förutom en rad projekt också historiska utblickar och samtidskritiska resonemang. En stor del av innehållet redovisades redan våren 1984 - det skedde genom en utställning på Arkitekturmuseet och en preliminär publikation. Materialet har sedan svällt ut med innehållsrika uppsatser om Centralen, om äldre och nyare insatser för att förena konst och arkitektur och om den föga kända, ännu obebyggda Blekholmen.
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| 8. |
- Gunnarson, Björn E., et al.
(författare)
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Legacies of pre-industrial land use can bias modern tree-ring climate calibrations
- 2012
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Ingår i: Climate Research (CR). - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 53:1, s. 63-76
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Tidskriftsartikel (refereegranskat)abstract
- In Scandinavia, dendrochronological reconstructions of past climate have mostly been based on tree-ring data from forests in which there has been, supposedly, very little or no human impact. However, human land use in sub-alpine forests has a substantially longer history and more profound effects on the forest ecosystems than previously acknowledged. Therefore, to assess human influence on tree-ring patterns over the last 500 yr, we have analyzed tree-ring patterns using trees from 2 abandoned Sami settlements and a reference site with no human impact-all situated in the Tjeggelvas Nature Reserve in north-west Sweden. The hypothesis was that land use legacies have affected tree-ring patterns, and in turn, the resulting palaeoclimate inferences that have been made from these patterns. Our results show that climate signals are strongest at the reference site and weakest at one of the settlement sites. From the 1940s to the present, tree growth at this settlement site has been significantly lower than at the reference site. Lower tree growth at old settlements may have resulted from rapid changes in the traditional land use, or following the abrupt change when the settlements were abandoned. Without site-specific know ledge of past land use, there is a high risk of accidently sampling trees that have been affected by human-induced disturbances in the past. This may create bias in the climate signals inferred from such trees, and hence bias the outcome of climate reconstructions. We therefore recommend sampling several separate sites in study areas to improve the robustness of inferences.
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| 9. |
- Hörnberg, Greger, et al.
(författare)
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Anthropogenic use of fire led to degraded scots pine-lichen forest in northern Sweden
- 2018
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Ingår i: ANTHROPOCENE. - : Elsevier BV. - 2213-3054. ; 24, s. 14-29
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Tidskriftsartikel (refereegranskat)abstract
- Northern pine-lichen forests are generally regarded as natural ecosystems that, in the past, were repeatedly affected by wild fires. This paper presents and tests a new hypothesis that reindeer herders used recurrent fires to promote and sustain reindeer lichen-dominated ground vegetation, in order to maintain good winter-grazing grounds in Scots pine forests. We investigated vegetation and fire history in three pine-lichen forests along the Lulealven River in northernmost Sweden. Methods included analyses of pollen, spores, charcoal and soil nutrient capital, coupled with investigation of written historical sources and previous studies. Results suggest that recurrent, intermediate-interval fires started sometime between the 2nd and 8th centuries CE, i.e. at the same time that reindeer became semidomesticated in this region. Such fires continued until the 18th century, when introduction of active fire suppression reduced the occurrence of fire in the landscape. Repeated burning over this long period eventually depleted the soil-nutrient capital, especially nitrogen and phosphorous, thereby severely reducing productivity. In the early 20th century, foresters described such forests as degraded. Results of this study add a new dimension to understanding the genesis and history of many pine-lichen forests. They challenge the notion that reindeer herders have been reluctant, in the past, to use fire. Further studies are needed to evaluate whether a similar history can be ascribed to pine-lichen forests in other parts of northern Fennoscandia. (C) 2018 The Author(s). Published by Elsevier Ltd.
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| 10. |
- Hörnberg, Greger, et al.
(författare)
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Indications of shifting cultivation west of the Lapland border: Multifaceted land use in northernmost Sweden since AD 800
- 2015
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Ingår i: Holocene. - : SAGE Publications. - 0959-6836 .- 1477-0911. ; 25, s. 989-1001
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Tidskriftsartikel (refereegranskat)abstract
- Permanent cultivation is generally believed to have been established in the interior of northernmost Fennoscandia later than elsewhere in northern Europe, during or after the late 17th century. Although subtle evidence from various pollen records suggests cultivation may have occurred much earlier in this region, such indications have generally been disregarded. We hypothesized that cultivation was introduced early in the Lapland border zone where western native Sami interacted with coastal farming societies due to the high degree of contact between these communities. Therefore, we investigated historical land usage at three settlement sites in the interior of Sweden's northernmost territories - two in the Lapland border zone and one in a more westerly traditional Sami area. Analyses of pollen, charcoal and written historical records indicated that cultivation first occurred in AD 800 (700-900) at the westernmost site and one of the border zone sites. Permanent cultivation appears to have been established in c. AD 1480 (1400-1560) and 1750 (1720-1810) in the two Lapland border zone settlements and around AD 1840 (1725-1940) in the westernmost settlement. These results suggest that small-scale shifting cultivation may have been conducted in inland regions of Northern Fennoscandia (including a traditional Sami area) since AD 800. As such, they support the hypothesis that intermittent small-scale cultivation has been going on in these regions for much longer than was previously accepted. Because there was a great mobility of people and ideas across northernmost Fennoscandia, we conclude that the current tendency to describe specific geographical regions as being solely used by nomadic herders' or permanent farmers' is inappropriate and fails to capture the complexity of historical land usage.
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