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Sökning: WFRF:(Lindberg Gunnar) > Luleå tekniska universitet

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1.
  • Andersson, Anders, et al. (författare)
  • Describing fish passage in a river confluence with telemetry and CFD
  • 2016
  • Konferensbidrag (refereegranskat)abstract
    • The confluence between hydropower tailrace and the old river bed in Stornorrfors in the river Umeälven in the northern part of Sweden has shown to be the largest obstacle for upstream migrating salmon and sea trout during the migrating season. Fish are attracted to the high flow rate from the tailrace and will not migrate upstream in the old river bed being the passage to the fishway leading past the hydropower dam. By triangulating the movements of radio tagged fish using eight antennas in the confluence, it is here possible to describe the individual fish tracks left by radio tagged fish during the migrating season. These tracks are then compared with three-dimensional Computational Fluid Dynamics (CFD) simulations of the confluence. By simulating the most common combinations of turbine flow and spill flow in the old river bed it is then possible to find correlations between individual fish movements and flow parameters such as velocity, turbulence intensity or vorticity for different flow combinations. It was previously assumed that fish had trouble locating the old river bed, the results of the triangulation however shows that most fish finds the old river bed within a few days but does not chose to migrate until several days (or weeks) later. The main issue to be solved is therefore not how to attract the fish to the old river bed but rather how to create favorable conditions in the old river bed so that migrating fish are more inclined to take that path upstream.
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2.
  • Hultkrantz, Lars, et al. (författare)
  • The value of improved road safety
  • 2006
  • Ingår i: Journal of Risk and Uncertainty. - Dordrecht : Springer. - 0895-5646 .- 1573-0476. ; 32:2, s. 151-170
  • Tidskriftsartikel (refereegranskat)abstract
    • We report the results of a contingent valuation study for finding a conservative estimate of the value-of-statistical-life in an urban road safety context in Sweden. We estimate the value of both a private-good device and a public-good safety program. The reduction of risk is communicated with a "community analogy" representation of the "Vision Zero" target of the national traffic-safety policy. According to this target, the road-traffic system should be designed so as to prevent accidents when they happen to lead to fatalities or severe injuries. We use the "certainty approach" for ex-post correction of results to remove or mitigate hypothetical bias of responses. As expected we find insensitivity of responses in the full sample to the size of the risk reduction being valued. By our approach we can compute a conservative estimate, based on answers from fully confident respondents, of the value of the largest possible safety enhancement (i.e. fulfilment of the "Vision Zero"). This lower bound estimate indicates a higher average willingness-to-pay for public safety-improving measures than currently assumed in benefit-cost assessments. We also find that the willingness to pay is considerably lower within a public-good than a private-good framework and a weak indication of sensitivity to scale among the most confident respondents.
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3.
  • Lundbäck, Bo, et al. (författare)
  • Not 15 But 50% of smokers develop COPD?—Report from the Obstructive Lung Disease in Northern Sweden Studies
  • 2003
  • Ingår i: Respiratory Medicine. - : Elsevier BV. - 0954-6111 .- 1532-3064. ; 97:2, s. 115-122
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: The prevalence of chronic obstructive pulmonary disease (COPD) according to guidelines of today seems considerably higher than has been reported also in recent literature.Aim: To estimate the prevalence of COPD as defined by British Thoracic Society (BTS) criteria and the recent global initiative for chronic obstructive lung disease (GOLD) criteria. Further aims were to assess the proportion of underdiagnosis and of symptoms in subjects with COPD, and to study risk factors for COPD.Methods: In 1996, 5892 of the Obstructive Lung Disease in Northern Sweden (OLIN) Study's first cohort could be traced to a third follow-up survey, and 5189 completed responses (88%) were received corresponding to 79% of the original cohort from December 1985. Of the responders, a random sample of 1500 subjects were invited to a structured interview and a lung function test, and 1237 of the invited completed a lung function test with acceptable quality.Results: In ages >45 years, the prevalence of COPD according to the BTS guidelines was 8%, while it was 14% according to the GOLD criteria. The absolutely dominating risk factors were increasing age and smoking, and approximately a half of elderly smokers fulfilled the criteria for COPD according to both the BTS and the GOLD criteria. Family history of obstructive airway disease was also a risk factor, while gender was not. Of those fulfilling the BTS criteria for COPD, 94% were symptomatics, 69% had chronic productive cough, but only 31% had prior to the study been diagnosed as having either chronic bronchitis, emphysema, or COPD. The corresponding figures for COPD according GOLD were 88, 51, and 18%.Conclusions: In ages >45 years, the prevalence of COPD according to the BTS guidelines was 8%, and it was 14% according to the GOLD criteria. Fifty percent of elderly smokers had developed COPD. The large majority of subjects having COPD were symptomatic, while the proportion of those diagnosed as having COPD or similar diagnoses was small.
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  • Resultat 1-4 av 4

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