| 1. |
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| 2. |
- Bergman, Annika, et al.
(författare)
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The western Swedish BRCA1 founder mutation 3171ins5; a 3.7 cM conserved haplotype of today is a reminiscence of a 1500-year-old mutation
- 2001
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Ingår i: European Journal of Human Genetics. - : Nature Publishing Group. - 1018-4813 .- 1476-5438. ; 9:10, s. 787-793
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Tidskriftsartikel (refereegranskat)abstract
- The most recurrent BRCA1/BRCA2 mutation in Sweden is the BRCA1 mutation 3171ins5. In the western part of Sweden this mutation accounts for as much as 77% of identified mutations in these two genes. Our aim was to analyse in detail the haplotype and founder effects of the 3171ins5 and furthermore attempt to estimate the time of origin of the mutation. In the study we included eighteen apparently unrelated families with hereditary breast and/or ovarian cancer. At least one individual in each family had previously tested positive for the 3171ins5 mutation. Polymorphic microsatellite markers were used for the haplotype analyses. The markers were located within or flanking the BRCA1 gene spanning a region of 17.3 cΜ. We found several different haplotypes both for disease alleles and for the normal alleles. However, a conserved haplotype of 3.7 cΜ was observed in the 3171ins5 carriers spanning over four markers located within or very close to the BRCA1 gene. As this haplotype was not present in any of the normal controls it is highly likely that this is a mutation identical by descent, i.e. a true founder. The results from the haplotype analyses were used to estimate the age of the mutation. Estimations based on the Pexcess and linkage disequilibrium gives a first appearance of the mutation sometime around the 6th century, approximately 50 generations ago.
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| 3. |
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| 4. |
- Blomberg, Lars G., et al.
(författare)
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EMMA - the electric and magnetic monitor of the aurora on Astrid-2
- 2004
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Ingår i: Annales Geophysicae. - : Copernicus GmbH. - 0992-7689 .- 1432-0576. ; 22:1, s. 115-123
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Tidskriftsartikel (refereegranskat)abstract
- The Astrid-2 mission has dual primary objectives. First, it is an orbiting instrument platform for studying auroral electrodynamics. Second, it is a technology demonstration of the feasibility of using micro-satellites for innovative space plasma physics research. The EMMA instrument, which we discuss in the present paper, is designed to provide simultaneous sampling of two electric and three magnetic field components up to about 1 kHz. The spin plane components of the electric field are measured by two pairs of opposing probes extended by wire booms with a separation distance of 6.7 m. The probes have titanium nitride (TiN) surfaces. which has proved to be a material with excellent properties for providing good electrical contact between probe and plasma. The wire booms are of a new design in which the booms in the stowed position are wound around the exterior of the spacecraft body. The boom system was flown for the first time on this mission and worked flawlessly. The magnetic field is measured by a tri-axial fluxgate sensor located at the tip of a rigid. hinged boom extended along the spacecraft spin axis and facing away from the Sun. The new advanced-design fluxgate magnetometer uses digital signal processors for detection and feedback, thereby reducing the analogue circuitry to a minimum. The instrument characteristics as well as a brief review of the science accomplished and planned are presented.
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| 5. |
- Blomberg, Lars G., et al.
(författare)
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Solar windmagnetosphere-ionosphere coupling : an event study based on Freja data
- 2004
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Ingår i: Journal of Atmospheric and Solar-Terrestrial Physics. - : Elsevier BV. - 1364-6826 .- 1879-1824. ; 66:5, s. 375-380
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Tidskriftsartikel (refereegranskat)abstract
- Freja data are used to study the relative contributions from the high-latitude (reconnection/direct entry) and low-latitude (viscous interaction) dynamos to the cross-polar potential drop. Convection streamlines which are connected to the high-latitude dynamo may be identified from dispersed magnetosheath ions not only in the cusp/cleft region itself but also several degrees poleward of it. This fact, together with Freja's orbital geometry allows us to infer the potential drop from the high-latitude dynamo as well as to obtain a lower limit to the potential drop from the low-latitude dynamo for dayside Freja passes. All cases studied here are for active magnetospheric conditions. The Freja data suggest that under these conditions at least one third of the potential is generated in the low-latitude dynamo. These observations are consistent with earlier observations of the potential across the low-latitude boundary layer if we assume that the low-latitude dynamo region extends over several tens of Earth radii in the antisunward direction along the tail flanks, and that the majority of the potential drop derives from the sun-aligned component of the electric field rather than from its cross-boundary component, or equivalently, that the centre of the dynamo region is located quite far down tail. A possible dynamo geometry is illustrated.
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| 6. |
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| 7. |
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| 8. |
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| 9. |
- Brogren, Maria, 1974-
(författare)
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Optical Efficiency of Low-Concentrating Solar Energy Systems with Parabolic Reflectors
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Solar electricity is a promising energy technology for the future, and by using reflectors for concentrating solar radiation onto photovoltaic cells, the cost per produced kWh can be significantly reduced. The optical efficiency of a concentrating system determines the fraction of the incident energy that is transferred to the cells and depends on the optical properties of the system components. In this thesis, low-concentrating photovoltaic and photovoltaic-thermal systems with two-dimensional parabolic reflectors were studied and optimised, and a new biaxial model for the incidence angle dependence of the optical efficiency was proposed. Concentration of light generally results in high cell temperatures, and the uneven irradiance distribution on cells with parabolic reflectors leads to high local currents and temperatures, which reduce fill-factor and voltage. Cooling the cells by means of water increases the voltage and makes it possible to utilize the thermal energy. The performance of a 4X concentrating photovoltaic-thermal system was evaluated. If operated at 50°C, this system would produce 250 kWhelectrical and 800 kWhthermal per m2 cell area and year. Optical performance can be increased by 20% by using better reflectors and anti-reflectance glazing. Low-concentrating photovoltaic systems for façade-integration were studied and optimised for maximum annual electricity production. The optimisation was based on measured short-circuit currents versus solar altitude. Measurements were performed outdoors and in a solar simulator. It was found that the use of 3X parabolic reflectors increases the annual electricity production by more than 40%. High solar reflectance is crucial to system performance but by using a low-angle scattering reflector, the fill-factor and power are increased due to a more even irradiance on the modules. Long-term system performance depends on the durability of the components. The optical properties and degradation of reflector materials were assessed using spectrophotometry, angular resolved scatterometry, Fresnel modelling, optical microscopy, and surface profilometry before and after ageing. The degradation of reflectors was found to be strongly dependent on material composition and environmental conditions. Back surface mirrors, all-metal reflectors, and polymer-metal laminates degraded in different ways, and therefore accelerated ageing must be tailored for testing of different types of reflector materials. However, new types of reflector laminates showed a potential for increasing the cost-effectiveness of low-concentrating solar energy systems.
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| 10. |
- Brogren, M, et al.
(författare)
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Optical properties, durability, and system aspects of a new aluminium-polymer-laminated steel reflector for solar concentrators
- 2004
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Ingår i: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 82:3, s. 387-412
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Tidskriftsartikel (refereegranskat)abstract
- A newly developed aluminium-polymer-laminated steel reflector for use in solar concentrators was evaluated with respect to its optical properties, durability, and reflector performance in solar thermal and photovoltaic systems. The optical properties of the reflector material were investigated using spectrophotometer and scatterometry. The durability of the reflector was tested in a climatic test chamber as well as outdoors in Alvkarleby (60.5degreesN, 17.4degreesE), Sweden. Before ageing, the solar weighted total and specular reflectance values were 82% and 77%, respectively, and the reflector scattered light isotropically. After I year's outdoor exposure, the total and specular solar reflectance had decreased by less than 11%. However, after 2000 h in damp heat and 1000 W/m(2) simulated solar radiation, the optical properties had changed significantly: The light scattering was anisotropic and the total and specular solar reflectance values had decreased to 75% and 42%, respectively. The decrease was found to be due to degradation of the protective polyethylene terephthalate (PET) layer, caused by UV radiation and high temperature. The conclusions are that the degradation is climate dependent and that PET is not suitable as a protective coating under extreme conditions, such as those in the climatic test chamber. However, the results from outdoor testing indicate that the material withstands exposure in a normal Swedish climate.
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| 11. |
- Carlsson, Arne, et al.
(författare)
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Emissionsmodell för tunnlar
- 2004
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Tunnels for road and street traffic become increasingly important for transport provisions, primarily in large cities. Currently, there are in Stockholm and Gothenburg high-volume tunnels in the primary road network. In addition, many new tunnels will soon be finalised or are planned both in Stockholm and Gothenburg. The exhaust emissions in road tunnels may not exceed certain limits. Road tunnels are equipped with ventilation systems to make sure that limits for air quality are not exceeded, primarily emissions of NO2. The ventilation systems are dimensioned using data on maximum expected emissions per unit of time. VTI has obtained a commission from the Swedish National Road Administration (SNRA) to develop a model for calculation of exhaust emissions in tunnels, which in addition shall take into account oversaturated conditions. Currently, SNRA has no satisfactory model for calculations at hourly level. The objective of the development effort has been to formulate a calculation model for travel speeds and emissions in motorway tunnels, to be used when tunnel ventilation systems are dimensioned. For a complete structure, the model shall provide individual tunnel tube emission data for hourly traffic, split upon homogenous - from the viewpoint of traffic engineering - road links and ventilation segments. This report describes the results of the development project for calculation of emissions in tunnels. The completed model comprises two parts, one for calculation of speed and corresponding hourly flow at given demand level and one for calculation of emissions, using hourly flows and speed as input data. For each part, there is a computer program with user manual. Test runs of the model for some basic typical tunnel cases, has been carried out to illustrate the results of the total model. The total emissions of NOx (kg/km) as a function of traffic flow have been calculated for different degree of traffic load. In addition, the model has been validated by comparisons of calculated NOx values from the model with measured NOx values in three different tunnels: the Gnistäng tunnel and the Tingstad tunnel in Gothenburg and the Southern Route tunnel in Stockholm.
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| 12. |
- Carlsson, Katrin, et al.
(författare)
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Fear and the Amygdala : Manipulation of Awareness Generates Differential Cerebral Responses to Phobic and Fear-Relevant (but Nonfeared) Stimuli
- 2004
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Ingår i: Emotion. - : American Psychological Association (APA). - 1528-3542 .- 1931-1516. ; 4:4, s. 340-353
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Tidskriftsartikel (refereegranskat)abstract
- Rapid response to danger holds an evolutionary advantage. In this positron emission tomography study, phobics were exposed to masked visual stimuli with timings that either allowed awareness or not of either phobic, fear-relevant (e.g., spiders to snake phobics), or neutral images. When the timing did not permit awareness, the amygdala responded to both phobic and fear-relevant stimuli. With time for more elaborate processing, phobic stimuli resulted in an addition of an affective processing network to the amygdala activity, whereas no activity was found in response to fear-relevant stimuli. Also, right prefrontal areas appeared deactivated, comparing aware phobic and fear-relevant conditions. Thus, a shift from top-down control to an affectively driven system optimized for speed was observed in phobic relative to fear-relevant aware processing. (PsycINFO Database Record (c) 2006 APA, all rights reserved) (journal abstract)
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| 13. |
- Einbeigi, Zakaria, 1962, et al.
(författare)
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Clustering of individuals with both breast and ovarian cancer--a possible indicator of BRCA founder mutations.
- 2002
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Ingår i: Acta oncologica (Stockholm, Sweden). - 0284-186X. ; 41:2, s. 153-7
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Tidskriftsartikel (refereegranskat)abstract
- In a cohort of 60436 women with a diagnosis of invasive breast carcinoma and known to reside in Sweden in 1960, 321 had a subsequent diagnosis of ovarian carcinoma. Assuming no correlation between the two cancers, one would expect that 191 women would develop ovarian cancer (standardized incidence ratio (SIR) 1.7; 95% confidence interval 1.5-1.9). Women with breast cancer before 40 years of age were at highest risk for developing ovarian cancer (SIR 4.5). Between 40 and 49 years of age, the SIR was 1.9, and at 50 years of age or older, the SIR was 1.3. Most of the excess in ovarian cancer occurred in southern Sweden. The geographic distribution of these cases coincided with the distribution of families with known BRCA1 and BRCA2 gene mutations. These results suggest that genetic factors account for the excess in ovarian cancer that occurs in breast cancer patients and that geographic clustering of patients who have both breast and ovarian cancer may indicate the presence of a BRCA founder mutation.
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| 14. |
- Ericson, Marica, 1974, et al.
(författare)
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Photodynamic therapy of actinic keratosis at varying fluence rates : Assessment of photobleaching, pain and primary clinical outcome
- 2004
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Ingår i: British Journal of Dermatology. - : Oxford University Press (OUP). - 0007-0963 .- 1365-2133. ; 151, s. 1204-1212
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Tidskriftsartikel (refereegranskat)abstract
- Background: Although photodynamic therapy (PDT) is becoming an important treatment method for skin lesions such as actinic keratosis (AK) and superficial basal cell carcinoma, there are still discussions about which fluence rate and light dose are preferable. Recent studies in rodents have shown that a low fluence rate is preferable due to depletion of oxygen at high fluence rates. However, these results have not yet been verified in humans. Objectives: The objective was to investigate the impact of fluence rate and spectral range on primary treatment outcome and bleaching rate in AK using aminolaevulinic acid PDT. In addition, the pain experienced by the patients has been monitored during treatment. Patients/methods Thirty-seven patients (mean age 71 years) with AK located on the head, neck and upper chest were treated with PDT, randomly allocated to four groups: two groups with narrow filter (580-650 nm) and fluence rates of 30 or 45 mW cm-2, and two groups with broad filter (580-690 nm) and fluence rates of 50 or 75 mW cm-2. The total cumulative light dose was 100 J cm-2 in all treatments. Photobleaching was monitored by fluorescence imaging, and pain experienced by the patients was registered by using a visual analogue scale graded from 0 (no pain) to 10 (unbearable pain). The primary treatment outcome was evaluated at a follow-up visit after 7 weeks. Results: Our data showed a significant correlation between fluence rate and initial treatment outcome, where lower fluence rate resulted in favourable treatment response. Moreover, the photo-bleaching dose (1/e) was found to be related to fluence rate, ranging from 4.5 ± 1.0 J cm -2 at 30 mW cm-2, to 7.3 ± 0.7 J cm-2 at 75 mW cm-2, indicating higher oxygen levels in tissue at lower fluence rates. After a cumulative light dose of 40 J cm-2 no further photobleaching took place, implying that higher doses are excessive. No significant difference in pain experienced by the patients during PDT was observed in varying the fluence rate from 30 to 75 mW cm-2. However, the pain was found to be most intense up to a cumulative light dose of 20 J cm-2. Conclusions: Our results imply that the photobleaching rate and primary treatment outcome are dependent on fluence rate, and that a low fluence rate (30 mW cm-2) seems preferable when performing PDT of AK using noncoherent light sources.
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| 15. |
- Gelin, Kristina, 1975-
(författare)
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Preparation and Characterization of Sputter Deposited Spectrally Selective Solar Absorbers
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The optical efficiency of a commercially available sputter deposited spectrally selective solar absorber was improved. The main purposes were to decrease the thermal emittance, increase the solar absorbtance of the absorber and to protect the substrate from degradation due to environmental influence. The adhesion properties between the corrosion-protecting barrier and the substrate were also studied. This project was focused on process improvements that are realistic to implement in industrial production.The thermal emittance of the absorber was decreased from 0.12 to 0.06 by changing the material of the corrosion-protecting layer from nickel-chromium to copper-nickel. Copper-nickel was less sensitive to variations in the sputter parameters than nickel-chromium. A novel method that could simplify the search for alternative corrosion resistant materials with a low thermal emittance has been purposed. Since resistivity data usually exist or can easily be measured and infrared measurements require more sophisticated measurements, the Hagen-Rubens relation was investigated for copper-nickel and nickel-chromium alloys. The dc-resistivity was found to be related to the infrared emittance or the integrated thermal emittance for alloys in their solid soluble fcc phase.The solar absorbtance was increased when a graded index absorbing coating was tailored for a crossover of the reflectance from low to high reflectance at about 2.5 µm. The solar absorber graded index coating was optimized for nickel metal content in nickel oxide and a solar absorptance of 0.89-0.91 was achieved. The solar absorptance was further increased to 0.97 when an antireflection coating was added on top of the absorbing layer.Finally, extrapolation algorithms were developed to assure correct determination of the thermal emittance for coatings on glass since modern spectrometers that do not cover the complete wavelength interval required to calculate the thermal emittance of surfaces at room temperatures accurately. The error arising from the extrapolation algorithms were smaller than the noise from the optical measurements. Similar strategies can be used for other surfaces.
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| 16. |
- Gustafsson, Georg, et al.
(författare)
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First results of electric field and density observations by Cluster EFW based on initial months of operation
- 2001
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Ingår i: Annales Geophysicae. - : Copernicus GmbH. - 0992-7689 .- 1432-0576. ; 19:12-okt, s. 1219-1240
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Tidskriftsartikel (refereegranskat)abstract
- Highlights are presented from studies of the electric field data from various regions along the CLUSTER orbit. They all point towards a very high coherence for phenomena recorded on four spacecraft that are separated by a few hundred kilometers for structures over the whole range of apparent frequencies from I mHz to 9 kHz. This presents completely new opportunities to study spatial-temporal plasma phenomena from the magnetosphere out to the solar wind. A new probe environment was constructed for the CLUSTER electric field experiment that now produces data of unprecedented quality. Determination of plasma flow in the solar wind is an example of the capability of the instrument.
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| 17. |
- Holmberg, Erik, 1951, et al.
(författare)
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Dose-response relationship for parathyroid adenoma after exposure to ionizing radiation in infancy.
- 2002
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Ingår i: Radiation research. - 0033-7587. ; 158:4, s. 418-23
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Tidskriftsartikel (refereegranskat)abstract
- Several authors have suggested that there is an excess risk of hyperparathyroidism, adenomas or hyperplasia after exposure to ionizing radiation. There is still, however, some uncertainty about this association, because these diseases are often asymptomatic and escape clinical detection if not specially searched for. This study is based on a pooled Swedish cohort of 27,925 persons with skin hemangiomas. The majority received radiation treatment in infancy between 1920 and 1965 in Stockholm and Gothenburg. The mean age at treatment was 6 months and the median thyroid dose was 0.20 Gy (range 0-28.5 Gy). Record linkage with the Swedish Cancer Register for the period 1958-1997 gave 43 cases of parathyroid adenoma in the cohort. Analyses of excess relative risk (ERR) models were performed using Poisson regression methods. Clinical records were scrutinized to determine if the childhood radiation exposure was known (biased cases) at the time of diagnosis. Seven of the cases of parathyroid adenoma were classified as biased cases. The standardized incidence ratio (SIR) was 2.10 (95% confidence interval 1.52-2.82) when all cases were included and 1.76 (95% CI 1.23-2.43) with the biased cases excluded. A linear dose-response model with stratification for sex fitted the data best. The ERR per gray was 3.84 (95% CI 1.56-8.99) with all cases and 1.56 (95% CI 0.36-4.45) with the biased cases excluded. There was a significant difference in the ERR per gray between the two subcohorts, probably because of different diagnostic activity in the regions. Our findings confirm that there is a dose-response relationship for radiation-induced parathyroid adenomas.
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| 18. |
- Johansson, Tommy, et al.
(författare)
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Intense high-altitude auroral electric fields : temporal and spatial characteristics
- 2004
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Ingår i: Annales Geophysicae. - : Copernicus GmbH. - 0992-7689 .- 1432-0576. ; 22:7, s. 2485-2495
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Tidskriftsartikel (refereegranskat)abstract
- Cluster electric field, magnetic field, and energetic electron data are analyzed for two events of intense auroral electric field variations, both encountered in the Plasma Sheet Boundary Layer (PSBL), in the evening local time sector, and at approximately 5 R-E geocentric distance. The most intense electric fields (peaking at 450 and 1600 mV/m, respectively) were found to be quasi-static, unipolar, relatively stable on the time scale of at least half a minute, and associated with moving downward FAC sheets (peaking at similar to10 muA/m(2)), downward Poynting flux (peaking at similar to35 mW/m(2)), and upward electron beams with characteristic energies consistent with the perpendicular potentials (all values being mapped to 1 R-E geocentric distance). For these two events in the return current region, quasi-static electric field structures and associated FACs were found to dominate the upward acceleration of electrons, as well as the energy transport between the ionosphere and the magnetosphere, although Alfven waves clearly also contributed to these processes.
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| 19. |
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| 20. |
- Karlsson, Kristin, et al.
(författare)
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The barrier approach for stormwater systems
- 2004
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Ingår i: Techniques et stratégies durables pour la gestion des eaux urbaines par temps de pluie. - Villeurbanne : Graie. - 2950933750 ; , s. 591-598
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Konferensbidrag (refereegranskat)abstract
- The Barriers Approach has been developed to identify possible ways to trace or decrease the sources of chemicals, to estimate the flows of chemicals in a stormwater system. Four kinds of barriers have been identified: organisational, structural, process, and behavioural. In order to investigate and explain the barriers, a case study was carried out in Hammarby Sjöstad. In this study, three scenarios were examined: a combined system, a separate system with no treatment, and a separate system with treatment by different BMPs. For the combined system, most of the pollutants are bound for the sewage sludge. For the separate system with no treatment, the pollutants will end up in the receiving waters, while for the separate system with treatment, most of the pollutants are bound for the sediments or soil
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| 21. |
- Karlsson, Maria
(författare)
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Market based programming and resource allocation
- 2003
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The subject of this thesis is the concept of market-oriented programming and market protocols. We want to solve an allocation problem where some resources are to be divided among a number of agents. Each agent has a utility function telling how much the current allocation is worth for it. The goal is to allocate the resources among the agents in a way that maximizes the sum of the utilities of all agents. To solve this problem we use the concept of markets to create mechanisms for computational implementation.To achieve the advantages of market-oriented programming, we have to consider the conceptual view of the problem a main design issue. We want to investigate the possibilities to build computationally effective mechanisms which maintain the intuitive, easy-to-understand structure of market-based approaches. In the first paper we look at two examples from the literature and show that conceptual improvements of the approaches will make agent behavior more realistic. This will also make the examples fit into a more general theory. In the second paper we create a market mechanism for handling combinatorial markets. The mechanism includes an auction, where each iteration runs in polynomial time. The mechanism shows good performance when the number of resources is relatively small compared to the number of agents.
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| 22. |
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| 23. |
- Li, Xuri, et al.
(författare)
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PDGF-C is a new protease-activated ligand for the PDGF alpha-receptor.
- 2000
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Ingår i: Nat Cell Biol. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 2:5, s. 302-9
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Tidskriftsartikel (refereegranskat)abstract
- Platelet-derived growth factors (PDGFs) are important in many types of mesenchymal cell. Here we identify a new PDGF, PDGF-C, which binds to and activates the PDGF alpha-receptor. PDGF-C is activated by proteolysis and induces proliferation of fibroblasts when overexpressed in transgenic mice. In situ hybridization analysis in the murine embryonic kidney shows preferential expression of PDGF-C messenger RNA in the metanephric mesenchyme during epithelial conversion. Analysis of kidneys lacking the PDGF alpha-receptor shows selective loss of mesenchymal cells adjacent to sites of expression of PDGF-C mRNA; this is not found in kidneys from animals lacking PDGF-A or both PDGF-A and PDGF-B, indicating that PDGF-C may have a unique function.
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| 24. |
- Magnusson, Lennart, 1952, et al.
(författare)
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Predicted and measured speech recognition performance in noise with linear amplification
- 2001
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Ingår i: Ear and Hearing. - : Ovid Technologies (Wolters Kluwer Health). - 0196-0202 .- 1538-4667. ; 22:1, s. 46-57
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The purpose of this study was to investigate the applicability of the Speech Intelligibility Index (SII) in hearing aid fitting. It was hypothesized that estimated speech intelligibility, based on the SII, could be a more reliable measure than real speech recognition results for comparing hearing aid characteristics. DESIGN: The test subjects were 29 elderly persons (66 to 80 yr) with mild-to-moderate hearing loss, who were using monaurally fitted linear hearing aids. They were selected from the files at Sahlgrenska hearing clinic. Speech recognition scores were obtained at fixed speech-to-noise ratios with Phonemically Balanced (PB) words in speech-weighted noise and in low-frequency noise. A Just-Follow-Conversation (JFC) test was performed with connected speech presented in the same background noises. The subjects were tested without hearing aid and with their hearing aids set at three different frequency responses. Predicted speech recognition scores were calculated for each condition based on the SII, complemented with a correction for sensorineural hearing impairment. The calculations involved speech and noise spectra, pure tone thresholds and insertion gain responses. RESULTS: For each condition, the measured speech recognition scores were, on average, well predicted by the calculated scores. The intra-individual standard deviation of the predicted scores was estimated to be about one percent unit. The group results of the JFC test were in agreement with the word recognition results for the aided conditions, but a floor effect was observed for the unaided conditions. CONCLUSIONS: Speech intelligibility prediction based on the modified SII is a valid estimate of speech recognition performance of hearing-impaired persons with mild-to-moderate hearing loss. Estimated intelligibility based on the SII is more reliable than actually measured speech recognition performance, for comparing amplification conditions within subjects.
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| 25. |
- Marklund, Göran T., et al.
(författare)
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Characteristics of quasi-static potential structures observed in the auroral return current region by Cluster
- 2004
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Ingår i: Nonlinear processes in geophysics. - : Copernicus GmbH. - 1023-5809 .- 1607-7946. ; 11:5-6, s. 709-720
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Tidskriftsartikel (refereegranskat)abstract
- Temporal and spatial characteristics of intense quasi-static electric fields and associated electric potential structures in the return current region are discussed using Cluster observations at geocentric distances of about 5 Earth radii. Results are presented from four Cluster encounters with such acceleration structures to illustrate common as well as different features of such structures. The electric field structures are characterized by (all values are projected to 100 cm altitude) peak amplitudes of approximate to 1V/m, bipolar or unipolar profiles, perpendicular scale sizes of approximate to 10km, occurrence at auroral plasma boundaries associated with plasma density gradients, downward field-aligned currents of approximate to 10 muA/m(2), and upward electron beams with characteristic energies of a few hundred eV to a few keV. Two events illustrate he temporal evolution of bipolar, diverging electric field strictures, indicative of positive U-shaped potentials increasing in magnitude from less than 1 kV to a few kV on a few 100s time scale. This is also the typical formation time for ionospheric plasma cavities, which are connected to the potential structure and suggested to evolve hand-in-hand with these. In one of these events an energy decay of inverted-V ions was observed in the upward field-aligned current region prior to the acceleration potential increase in the adjacent downward current region, possibly suggesting that a potential redistribution took place between the two current branches. The other two events were characterized by intense unipolar electric fields, indicative of S-shaped potential contours and were encountered at the polar cap boundary. The total observation time for these events was typically 10-20 s, too short for monitoring the evolution of the structure, bui yet of interest for revealing their short term stability. The locations of the two bipolar events at the poleward boundary of the central plasma sheet and of the two unipolar events at the polar cap boundary, suggest that the special profile shape depends on whether plasma populations, dense enough to support upward field-aligned currents and closure of the return current, exist on both sides, or on one side only, of the boundary.
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| 26. |
- Marklund, Göran T., et al.
(författare)
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Temporal evolution of the electric field accelerating electrons away from the auroral ionosphere
- 2001
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 414:6865, s. 724-727
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Tidskriftsartikel (refereegranskat)abstract
- The bright night-time aurorae that are visible to the unaided eye are caused by electrons accelerated towards Earth by an upward-pointing electric field(1-3). On adjacent geomagnetic field lines the reverse process occurs: a downward-pointing electric field accelerates electrons away from Earth(4-11). Such magnetic-field-aligned electric fields in the collisionless plasma above the auroral ionosphere have been predicted(12), but how they could be maintained is still a matter for debate(13). The spatial and temporal behaviour of the electric fields-a knowledge of which is crucial to an understanding of their nature-cannot be resolved uniquely by single satellite measurements. Here we report on the first observations by a formation of identically instrumented satellites crossing a beam of upward-accelerated electrons. The structure of the electric potential accelerating the beam grew in magnitude and width for about 200 s, accompanied by a widening of the downward-current sheet, with the total current remaining constant. The 200-s timescale suggests that the evacuation of the electrons from the ionosphere contributes to the formation of the downward-pointing magnetic-field-aligned electric fields. This evolution implies a growing load in the downward leg of the current circuit, which may affect the visible discrete aurorae.
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| 27. |
- Moroianu, Dragos, et al.
(författare)
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LES of the flow and particle ingestion into an air intake of a jet engine running on the ground
- 2004
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Ingår i: Proc. ASME Turbo Expo. - : ASMEDC. ; 2, s. 209-217
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Konferensbidrag (refereegranskat)abstract
- The flow field generated by the flow into a jet engine air-intake, with near ground effects, is considered. The axial inflow in the neighborhood of the ground generates a system of unsteady vortices. Some of these vortices extend from the air-intake towards the ground. Some of these vortices are strong enough to dislocate and even lift small objects from the ground up to the air-intake. The dynamics of the vortex system makes it difficult to study the problem by standard numerical and experimental methods. The dynamics of the vortices can be captured by using Large Eddy Simulations (LES), which is used here to enhance the understanding of the dynamics of the flow field. The computed flow field is used also to assess the ingestion of particles into the air-intake. It is shown that particles of several mm sizes can be ingested into the jet engine. This in turn may result in enhanced erosion of the compressor blades. The results of the computations in terms of mean velocity field have been compared to experimental data. These results are in good agreement with the experiments.
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| 28. |
- Svanström, Yvonne, 1965-
(författare)
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Policing Public Women : The Regulation of Prostitution in Stockholm 1812-1880
- 2000
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This dissertation studies the development of a regulation of prostitution in Stockholm during the period 1812-1880. The development of the regulation system is seen in the light of an analytical framework, developed from Carole Pateman's ideas on the sexual contract, and a feministic critique and elaboration of Jürgen Habermas's ideas on the public sphere.The regulation of prostitution was a common characteristic for many metropolises in Europe during the nineteenth century, where supposedly loose and lecherous women were medically and spatially controlled to impede the spread of venereal diseases. Stockholm, and Sweden as a whole, went from a non-gendered to a gendered control of venereal disease, which eventually developed into a spatial control of public women.This study argues that the practices of a regulation system was at first part of an attempt to import what was seen as part of modernisation. Rather than to prohibit extra-marital sexual relations, these were to be controlled and supervised. Eventually the system was adapted to local circumstances in Stockholm, and a control of women's sexuality in public became part of a metropolitan modernity.In the process of the professionalisation of groups such as the police and the physicians, public women were over time perceived as a group of professional prostitutes. The possibility to live off prostitution as a transitory stage in women's lives disappeared, and prostitution became a medically and spatially controlled trade.
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| 29. |
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