Tourists’ landscape perceptions and preferences in a Scandinavian coastal region

European cultural landscapes have been subject to change since the middle of the twentieth century, and among the most significant alterations are general re-growth, reforestation, and overgrowth. Such changes might lead to landscape loss for locals and deterioration of vistas for sightseeing holidaymakers. This article responds to a lack of academic research on landscape perceptions among tourists. The main objective is to explore international tourists’ landscape perceptions in a coastal area in northern Scandinavia, focusing on three different concepts thought to be important for tourists’ landscape preferences: typicality, vegetation lushness, and degree of human influence. A combination of free and directed sorting procedures was employed. Quantitative and categorical data derived from the multiple sorting methods were subjected to multidimensional scaling analysis. The results indicate that foreign tourists might have an understanding of re-growth in the case area. Preference ratings gave mixed results in relation to vegetation and human influence as important features for landscape preferences, as found in previous studies. The findings emphasise the need for taking into consideration typicality of setting in future landscape research.     

Effect of phosphorus poisoning on catalytic activity of diesel exhaust gas catalyst components containing oxide and Pt

Effects of phosphorus poisoning on the activity of powdered exhaust gas catalyst components containing different oxides and platinum were studied. The decrease in the catalytic activity was associated with phosphorus compounds formed with the catalyst components. The poisoned samples were studied using XRD and FTIR-ATR techniques. The same compounds, phosphates of cerium, zirconium, aluminium and titanium, have also been detected in vehicle aged diesel catalyst converters.     

Modeling the electrical activity of the heart: A Bidomain Model of the ventricles embedded in a torso

In this paper a model for the electrical activity of the heart will be presented and an approach to solve the resulting numerical problem will be suggested. The Bidomain Model is used to compute the spatial distribution of the electrical potential. The partial differential equations are discretized with the finite element method and the multigrid method is used to solve the corresponding linear equations. Adaptivity is applied to resolve the steep gradients in the solution. Received: 24 January 2000 / Accepted: 29 June 2002 / Published online: 10 April 2003 Communicated by G. Wittum     

Unstable eigenmodes are possible drivers for cardiac arrhythmias

The well-organized contraction of each heartbeat is enabled by an electrical wave traversing and exciting the myocardium in a regular manner. Perturbations to this wave, referred to as arrhythmias, can lead to lethal fibrillation if not treated within minutes. One manner in which arrhythmias originate is an ill-fated interaction of the regular electrical signal controlling the heartbeat, the sinus wave, with an ectopic stimulus. It is not fully understood how and when ectopic waves are generated. Based on mathematical models, we show that ectopic beats can be characterized in terms of unstable eigenmodes of the resting state.     

Noise, sleep and poor health: Modeling the relationship between road traffic noise and cardiovascular problems

Several adverse effects have been associated with exposure to traffic noise. Studies supporting a noise-stress-health model have suggested links between noise level and increased noradrenalin concentrations in urine, hypertension and myocardial infarction. Among the more commonly documented effects, sleep disturbances have been regarded as being the most serious. Both noise annoyance and sleep disturbance have been proposed as important mediators of the impact of noise on health. The present paper investigates the relationships among long-term noise exposure, annoyance, sleeping problems and subjective health complaints by the use of a structural equation model. Further, it aims at giving insight into how noise sensitivity is related to sleep disturbances from road traffic noise. Finally, it examines whether any effect of noise exposure or response to noise can be detected on prevalence of cardiovascular problems, when information on sleep disturbances is included in a model. Data from a questionnaire survey conducted among a population sample in Oslo (N = 2786) are combined with nighttime noise levels calculated from outside each respondents dwelling, at the bedroom façade. The results of the analysis showed significant relationships between noise annoyance at night and sleeping problems. The model also showed strong links among pseudoneurological complaints, annoyance and sleeping problems, thus pointing to the importance of including information on psychosomatic disorders and mild psychological problems in future studies looking at potential health effects of noise. The analysis showed no relationship between neither noise exposure nor response to noise and cardiovascular problems.     

Laboratory scale simulation of three-way catalyst engine ageing

In this work, a laboratory ageing cycle simulating the real engine ageing for three-way catalysts was developed. The laboratory cycle was created based on the rapid ageing hot (RAH) cycle used in the engine bench ageings. The simultaneous gas concentration and temperature changes were achieved by adjusting the IR-furnace and the gas flow parameters. The laboratory ageing cycle was verified by testing different samples after different ageings with the laboratory and the engine tests. In addition, some characterization methods: specific surface area (BET-method), dispersion (CO-chemisorption), particle size (CO-chemisorption) and oxygen storage capacity (with CO–O₂ exchange experiments), were used to compare the effect of the different ageings on the catalyst samples.     

Computing the size and location of myocardial ischemia using measurements of ST-segment shift

It is well known that the presence of myocardial ischemia can be observed as a shift in the ST segment of an electrocardiogram (ECG) recording. The question we address in this paper is whether or not ST shift can be used to compute approximations of the size and location of the ischemic region. We begin by investigating a cost functional (measuring the difference between synthetic recorded data and simulated values of ST shift) for a parameter identification problem to locate the ischemic region. We then formulate a more flexible representation of the ischemia using a level set framework and solve the associated minimization problem for the size and position of the ischemia. We apply this framework to a set of ECG data generated by the Bidomain model using the cell model of Winslow et al. Based on this data, we show that values of ST shift recorded at the body surface are capable of identifying the position and (roughly) the size of the ischemia.     

Rh oxide reducibility and catalytic activity of model Pt–Rh catalysts

Pt and Rh were impregnated by different methods into the washcoat to investigate the differences in Rh oxidation state and catalytic activity of the samples. Both fresh and laboratory aged samples were studied. Clear differences in catalytic activity were noticed between the catalysts with different Pt and Rh addition methods. The best oxidation activity for fresh catalysts was achieved with the catalyst having both Pt and Rh deposited into the Ce–Zr mixed oxide. However, this state was observed to be unstable, and hence, this particular catalyst was dramatically deactivated in air ageing at high temperature. After ageing, the catalyst having both Pt and Rh impregnated lastly into the entire calcined washcoat matrix had the best activity in all three reactions, carbon monoxide and hydrocarbon oxidation and nitrogen oxide reduction. According to XPS studies, Rh was in easily reducible form in all the fresh samples. After ageing, the highest portion of reducible Rh was observed in the sample having also the best catalytic activity.     

Emotional reactions to cycle helmet use

It has been suggested that the safety benefits of bicycle helmets are limited by risk compensation. The current article tests if previous helmet use influences the response to helmets as a safety intervention. This was investigated in a field experiment where pace and psychophysiological load were measured. We found that after having removed their helmets, routine helmet users cycled more slowly and demonstrated increased psychophysiological load. However, for non-users there was no significant change in either cycling behaviour or psychophysiological load. We discuss the implications of these results for a hypothesis of risk compensation in response to helmet use. We also show that heart rate variability is a promising measure of psychophysiological load in real-world cycling, at least in situations where there is limited physical demand.     

The role of casting porosity in fatigue properties of Al−Si 319 lost foam cast alloy

The tensile, fracture toughness and fatigue properties of Al−Si 319 lost-foam-cast alloy were determined at room temperature. The fatigue properties of this alloy were also determined at 150°C. Fatigue cracks were always initiated at the largest casting pore. Initial pore sizes were measured using a scanning electron microscope. Surface replication showed that majority of the fatigue life was spent in fatigue crack propagation and permitted the estimation of the constants in the Paris power law and the threshold stress intensity factor (ΔK _th ). The role of internal casting porosity was quantified using a linear elastic fracture mechanics (LEFM) model for fatigue crack growth. The predicted lives agreed with the measured values within a factor of two.