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- Dahlgren, Hanna, et al.
(author)
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First direct optical observations of plasma flows using afterglow of O+ in discrete aurora
- 2009
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In: Journal of Atmospheric and Solar-Terrestrial Physics. - : Elsevier BV. - 1364-6826 .- 1879-1824. ; 71:2, s. 228-238
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Journal article (peer-reviewed)abstract
- Imaging of active structured aurora in the forbidden O+ ion line at 732.0 nm provides a possibility of direct observation of plasma drifts in the topside ionosphere. The metastable O+ P-2 state has a radiative lifetime of 5 s, so the oxygen ions can be detected after the precipitation creating them has ceased. The decay time of the O+ emission is studied and modelled with a time-dependent electron transport and ion chemistry model. Four examples are given of O+ afterglow observed with the multi-spectral imager, auroral structure and kinetics (ASK), which was located near Tromso, Norway, in 2006. Estimates are given of drift velocities resulting from the analysis of the afterglow motions. Bulk plasma velocities of 340 and 720 m/s directed eastwards were found for two afterglowing arc filaments, corresponding to southward electric fields of 18 and 40 mV/m, respectively.
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- Dahlgren, Hanna, 1980-, et al.
(author)
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Morphology and dynamics of aurora at fine scale : first results for the ASK instrument
- 2008
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In: Annales Geophysicae. - : Copernicus GmbH. - 0992-7689 .- 1432-0576. ; 26:5, s. 1041-1048
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Journal article (peer-reviewed)abstract
- The ASK instrument (Auroral Structure and Kinetics) is a narrow field auroral imager, providing simultaneous images of aurora in three different spectral bands at multiple frames per second resolution. The three emission species studied are O-2(+) (5620 angstrom), O+ (7319 angstrom) and O (7774 angstrom). ASK was installed and operated for the first time in an observational campaign on Svalbard, from December 2005 to March 2006. The measurements were supported by data from the Spectrographic Imaging Facility (SIF). The relation between the morphology and dynamics of the visible aurora and its spectral characteristics is studied for selected events from this period. In these events it is found that dynamic aurora is coupled to high energy electron precipitation. By studying the O-2(+)/O intensity ratio we find that some auroral filaments are caused by higher energy precipitation within regions of lower energy precipitation, whereas other filaments are the result of a higher particle flux compared to the surroundings.
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- Dahlgren, Hanna, 1980-, et al.
(author)
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Using spectral characteristics to interpret auroral imaging in the 731.9 nm 0+ line
- 2008
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In: Annales Geophysicae. - : Copernicus GmbH. - 0992-7689 .- 1432-0576. ; 26:7, s. 1905-1917
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Journal article (peer-reviewed)abstract
- Simultaneous observations were made of dynamic aurora during substorm activity on 26 January 2006 with three high spatial and temporal resolution instruments: the ASK (Auroral Structure and Kinetics) instrument, SIF (Spectrographic Imaging Facility) and ESR (EISCAT Svalbard Radar), all located on Svalbard (78° N, 16.2° E). One of the narrow field of view ASK cameras is designed to detect O+ ion emission at 731.9 nm. From the spectrographic data we have been able to determine the amount of contaminating N2 and OH emission detected in the same filter. This is of great importance to further studies using the ASK instrument, when the O+ ion emission will be used to detect flows and afterglows in active aurora. The ratio of O+ to N2 emission is dependent on the energy spectra of electron precipitation, and was found to be related to changes in the morphology of the small-scale aurora. The ESR measured height profiles of electron densities, which allowed estimates to be made of the energy spectrum of the precipitation during the events studied with optical data from ASK and SIF. It was found that the higher energy precipitation corresponded to discrete and dynamic features, including curls, and low energy precipitation corresponded to auroral signatures that were dominated by rays. The evolution of these changes on time scales of seconds is of importance to theories of auroral acceleration mechanisms.
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- Glimskär, Anders, et al.
(author)
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Småbiotopsuppföljning i NILS år 2006
- 2007
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Reports (other academic/artistic)abstract
- Denna rapport presenterar resultat för mängden av småbiotoper vid åkermark i det svenska landskapet. Resultaten baseras på flygbildstolkningen inom det nationella miljöövervakningsprogrammet NILS (Nationell Inventering av Landskapet i Sverige). Analyserna görs på uppdrag av Jordbruksverket, som underlag för bl.a. utvärderingen av miljökvalitetsmålet Ett rikt odlingslandskap. Särskilda rutiner har tagits fram för att välja ut de småbiotoper som uppfyller de krav som Jordbruksverket har ställt upp, ur den befintliga databasen. Urvalet av småbiotoper är anpassat för att överensstämma med det urval av natur- och kulturmiljöer som ingår i det s.k. KULT-stödet (miljöersättning till lantbrukare) inom Miljö- och landsbygdsprogrammet.Arbetet har utförts vid institutionen för skoglig resurshushållning, Sveriges lantbruksuniversitet, Umeå. NILS är ett rikstäckande miljöövervakningsprogram som följer tillstånd och förändringar i det svenska landskapet och hur dessa påverkar förutsättningarna för den biologiska mångfalden. NILS finansieras av Naturvårdsverket, där NILS ingår i programområde Landskap. Ett viktigt syfte med NILS är att följa upp de nationella miljökvalitetsmålen för olika naturtyper och fungera som underlag för att till exempel visa om genomförda miljövårdsåtgärder leder till önskade förbättringar på nationell nivå eller landsdelsnivå.
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- Marklund, B, et al.
(author)
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Prevalence of unknown asthma and COPD in people with persistent or recurrent cough
- 2006
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In: Practice Nursing. - 0964-9271. ; 17:4, s. 197-200
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Journal article (peer-reviewed)abstract
- Coughing is the most common symptom in people attending primary health care. Because the prevalence of asthma and chronic obstructive pulmonary disease (COPD) is not well known, the aim of this study was to establish the prevalence of unknown asthma and COPD in people consulting for a persistent or recurrent cough in primary health care in Sweden. Seventy-two adult patients were recruited consecutively at an acute consultation with a medical history of a persistent or recurrent cough. A medical history and a physical examination were performed according to a standardized form. Four patients (6%) fulfilled the criteria for asthma and five (7%) for COPD. The prevalence of asthma in this sample was less than that in western countries generally. These findings highlight the importance of people, especially women and smokers, with persistent or recurrent cough being carefully and promptly assessed with standardized measures including spirometry and repeated peak expiratory flow measurements. This knowledge should he conveyed to the general public as well as to primary health professionals.
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- Marklund, Magnus, et al.
(author)
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Determination of the influence of uncertain model parameters in pressurized gasification of black liquor using a factorial design
- 2005
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In: Combustion Science and Technology. - : Informa UK Limited. - 0010-2202 .- 1563-521X. ; 177:3, s. 435-453
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Journal article (peer-reviewed)abstract
- Introduction of pressurized gasification of black liquor in the pulping industry has the potential to give a significant increase in energy efficiency. However, uncertainties about the reliability and robustness of the technology are preventing large-scale market introduction. One important step toward a greater trust in the process reliability is the development of a better understanding of the sensitivity of the process to parameter variations. A computational fluid dynamics model for pressurized gasification of black liquor in an entrained-flow gasifier is presented and used for investigation of the effects of uncertainties in the specific heat capacity of black liquor, the radiation absorption coefficient, and the volatile devolatilization rate using factorial design methodology. It is found that all main factor effects, but none of the interaction effects, influence the considered responses: char conversion, maximum temperature, and outlet temperature. However, the main effects are found to be relatively small and the uncertainties in the examined model parameters would not invalidate the results from a design optimization with the presented model. Copyright © Taylor & Francis Inc.
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- Ström, M., et al.
(author)
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Nurses' perceptions of providing advice via a telephone care line
- 2006
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In: British Journal of Nursing. - London : Mark Allen Publishing. - 0966-0461 .- 2052-2819. ; 15:20, s. 1119-1125
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Journal article (peer-reviewed)abstract
- The provision of advice over the telephone in the health service has become more common in the Western world and in Sweden this task is allocated to nurses. There are several million calls a year to the medical care telephone helpline. Nurses answer the calls, provide advice and direct the flow of patients to the most appropriate treatment level. The aim of this study was to describe how nurses perceive their job of providing telephone advice to patients. Interviews with 12 nurses were analyzed using a phenomenographic approach. The nurses perceived their work as stimulating, autonomous and challenging. They also felt exposed because extensive knowledge is required and there is a risk of being criticized, as they are in a front-line position. Nurses who are responsive, determined and not anxious about their prestige can carry out the work well, provided they have a good level of self-awareness. Personal qualities and the confidence of superiors make even an exposed position with considerable requirements manageable.
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