| 1. |
- Bartels, Pia, et al.
(författare)
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Water transparency drives intra-population divergence in Eurasian perch (Perca fluviatilis)
- 2012
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Ingår i: PLOS ONE. - San Francisco : Public Library of Science (PLoS). - 1932-6203. ; 7:8
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Tidskriftsartikel (refereegranskat)abstract
- Trait combinations that lead to a higher efficiency in resource utilization are important drivers of divergent natural selection and adaptive radiation. However, variation in environmental features might constrain foraging in complex ways and therefore impede the exploitation of critical resources. We tested the effect of water transparency on intra-population divergence in morphology of Eurasian perch (Perca fluviatilis) across seven lakes in central Sweden. Morphological divergence between near-shore littoral and open-water pelagic perch substantially increased with increasing water transparency. Reliance on littoral resources increased strongly with increasing water transparency in littoral populations, whereas littoral reliance was not affected by water transparency in pelagic populations. Despite the similar reliance on pelagic resources in pelagic populations along the water transparency gradient, the utilization of particular pelagic prey items differed with variation in water transparency in pelagic populations. Pelagic perch utilized cladocerans in lakes with high water transparency and copepods in lakes with low water transparency. We suggest that under impaired visual conditions low utilization of littoral resources by littoral perch and utilization of evasive copepods by pelagic perch may lead to changes in morphology. Our findings indicate that visual conditions can affect population divergence in predator populations through their effects on resource utilization.
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| 5. |
- Fredriksson, Rikard
(författare)
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Priorities and potential of pedestrian protection : accident data, experimental tests and numerical simulations of car-to-pedestrian impacts
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Pedestrian disability and fatality as a consequence of car crashes is a large global health problem. To introduce maximally effective car-based countermeasures it is important to understand which injuries are most common and from which car parts they originate. It is also important to focus on the most severe injuries resulting in disability or death. The aim of this thesis was therefore to determine priorities for and evaluate the potential of car-mounted safety systems designed to mitigate severe upper-body injuries (including disability and fatality) of pedestrians in car crashes. Accident data was collected from two areas; severe (AIS3+) accidents in Dresden/Hannover in Germany and fatal accidents in Sweden. For the surviving pedestrians an estimate of long-term injury was performed using accident data- derived risk matrices of permanent injury. Results showed that 31% would sustain a permanent impairment of some kind and 5% would sustain a more severe impairment, where the head was most susceptible to severe impairment. The car front frequently caused leg injuries, which is addressed in current regulations. However, current legal tests do not address the most common upper-body injury source, the windshield, which was found to be the dominating cause of head injuries. Chest injuries, frequently caused by both the hood and windshield areas in the severe and fatal crashes in this thesis, are also unaddressed in legal tests. Children are most commonly head-injured from the hood area, which is addressed in current regulations. Further, regulations do not fully consider brain injury with the current head test methods. Therefore, in this thesis focus was on upper-body injury/source combinations not addressed in the regulations, that is, the head-to-windshield area and chest-to-hood/windshield areas, and the evaluation of brain injury in hood and windshield impacts. Experimental head-to-hood component tests with succeeding brain simulations were performed to evaluate the influence of the under-hood distance and head impact speed. A hood designed to minimize linear head loading to acceptable injury levels was also found effective in reducing combined linear/rotational brain loading. Further, in full-scale car-to-pedestrian finite element simulations both a braking and deployable system alone proved efficient in reducing head and chest loading, and an integrated countermeasure of combining the two systems proved to increase the protection potential. While current pedestrian countermeasures focus on the head-to-hood impact, this thesis recommends extending countermeasures to the lower part of the windshield and the A-pillars, and adding brain and chest injury assessment for both hood and windshield areas to effectively minimize disabling and fatal injuries. Since head impact location and head impact speed is dependent on the car design, the introduction of full-scale simulations in the test methods to determine impact conditions for experimental component tests is recommended. If the deployable countermeasures are combined with autonomous braking in an integrated system the most effective system is achieved. Auto-brake systems should, in high speed impacts, aim to reduce speeds to where the secondary countermeasures can effectively mitigate injury. Future pedestrian test methods should therefore evaluate how primary and secondary countermeasures interact.
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| 6. |
- Fredriksson, Robert, et al.
(författare)
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The solute carrier (SLC) complement of the human genome : phylogenetic classification reveals four major families
- 2008
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Ingår i: FEBS Letters. - : Wiley. - 0014-5793 .- 1873-3468. ; 582:27, s. 3811-3816
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Tidskriftsartikel (refereegranskat)abstract
- Solute carriers (SLCs) is the largest group of transporters, embracing transporters for inorganic ions, amino acids, neurotransmitters, sugars, purines and fatty acids among other substrates. We mined the finished assembly of the human genome using Hidden Markov Models (HMMs) obtaining a total of 384 unique SLC sequences. Detailed clustering and phylogenetic analysis of the entire SLC family showed that 15 of the families place into four large phylogenetic clusters with the largest containing eight SLC families, suggesting that many of the distinct families of SLCs have a common evolutionary origin. This study represents the first overall genomic roadmap of the SLCs providing large sequence sets and clarifies the phylogenetic relationships among the families of the second largest group of membrane proteins.
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| 7. |
- Fredriksson, Sverker
(författare)
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A (ud)-cious model of the proton
- 1994
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Ingår i: Workshop on diquarks II. - Singapore : World Scientific and Engineering Academy and Society. - 9810216769 ; , s. 14-23
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Konferensbidrag (refereegranskat)
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| 8. |
- Fredriksson, Sverker
(författare)
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Cosmic diquarks
- 1998
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Ingår i: Workshop on Diquarks III. - Singapore : World Scientific Publishing Co Pte Ltd. - 9810236352 ; , s. 99-108
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Konferensbidrag (refereegranskat)
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| 9. |
- Fredriksson, Sofie, 1983, et al.
(författare)
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Current perspective on children’s auditory perception and consequences of noise exposure effects
- 2013
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Ingår i: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Exposure to high sound pressure levels is well known to cause auditory damage, regardless of age. There is however limited knowledge of the effects on hearing due to noise exposure early in life. In addition, no well-established model is used to describe how children perceive and experience their sound environment compared to adults. New studies of children’s hearing have revealed different directivity pattern especially at high frequencies given by the head-related transfer functions due to the anthropometric data of the children and also an ear canal resonance at considerable higher frequencies compared to adults. Recent studies also describe children feeling a great deal of discomfort when exposed to sounds with high frequency characteristics. Children today are exposed to high sound levels from an early age at preschool, school and during leisure time. Few studies have looked at general health effects or hearing in particular. It is being discussed whether age related hearing loss, regarded as an inevitable part of life, to a large extent may be caused by a lifetime of noise exposure starting early in life. This paper will review available studies on noise induced hearing damage among children and give suggestions for future studies within this field.
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