| 1. |
- Andéhn, Mikael, 1982-
(författare)
-
Place-of-Origin Effects on Brand Equity : Explicating the evaluative pertinence of product categories and association strength
- 2013
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The country-of-origin effect - the alteration of judgment derived from an association to a place, is a much studied phenomenon with great potential implications for brand management and international marketing. However, in light of criticism towards the lack of conceptual development the extant literature, the relevance of the effect has been brought into question.Through an exploration of the psychology of the association between brands and places, the country-of-origin effect is reimagined focusing on the role of association strength as well as how the interplay between place and product categories can shape consumer attitudes.The results of a series of psychometric tests suggest that association strength and the interplay between place and product category constitute antecedent conditions that are crucial for determining if a country-of-origin effect will occur. These findings, and their implications for future research as well as for practice, suggest that a reevaluation of the country-of-origin effect with a widening of the scope to encompass the commercial relevance of place writ large is warranted.
|
|
| 2. |
- Zinke, Julika, 1995-
(författare)
-
Factors influencing emission fluxes and bacterial enrichment in sea spray aerosols : Insights from laboratory and field studies
- 2023
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sea spray aerosol (SSA) is one of the major natural aerosol sources and is produced when wave breaking entrains air into ocean surface water, which subsequently breaks up into bubbles. These bubbles rise to the surface and can scavenge biogenic material. Once they reach the surface, they burst and produce both a large number of relatively small film drops that result from the disintegration of the bubble film cap and a smaller number of jet drops that result from the collapse of the bubble cavity and are typically larger in size than the film drops. The production of SSA is influenced by several factors, including wind speed, sea state, seawater temperature, salinity, and the physicochemical and biological condition of the ocean. SSA can significantly impact Earth's radiation budget by scattering incoming solar radiation directly and by acting as cloud condensation nuclei. To improve our understanding of the impact of sea spray aerosols on the Earth’s climate, it is critical to understand the physical mechanisms which determine the size-resolved SSA production flux. Furthermore, SSA can be a vector for the emission of primary biological airborne particles (PBAP) from the oceans to the atmosphere. PBAP encompass bacteria, viruses, pollen and spores and can be present in the atmosphere in form of agglomerates, single particles or cell fractions. Although, the abundance of PBAP typically only make up < 0.1% of the number of aerosols, this does not imply their insignificance. On the contrary, PBAP are known to be very efficient cloud- and ice condensation nuclei and thus can influence cloud properties such as cloud phase, albedo and lifetime, thereby affecting the Earth’s climate as well as biogeochemical cycles. As the Earth is 70% covered by oceans, of which most could be characterized as remote, quantifying the PBAP emissions over these waters are important for the enhancement of climate models.The goal of this thesis was to study the factors impacting SSA emissions and the emission of primary biological particles with SSA with particular focus on bacteria emissions. This was done both through laboratory and field experiments in the Baltic Sea and in the Azores archipelago using a plunging jet sea spray simulation chamber and various techniques to characterize aerosol emissions. More specifically, a parameterization for the SSA production flux as a function of salinity and temperature was derived from laboratory experiments and a wind speed and sea state dependent parameterization were derived from ambient eddy covariance (EC) flux measurements in the Baltic Sea. The combination of EC flux measurements and laboratory generated SSA allowed to derive a chamber specific scaling factor that could be applied to derive bacteria emission fluxes ranging between 16-63 cells m−2 s−1 from the Baltic Sea. Bacteria were found to be 13-488 and 9-148 times enriched in SSA compared to the underlying seawater from mesocosm experiments in the Baltic Sea and Azores, respectively. A comparison of single cell abundance estimates from fluorescence microscopy and real-time measurements of PBAP with diameters > 0.8 µm using a bioaerosol sensor revealed that the latter yielded consistently lower concentrations. The discrepancy was explained by differences in the sampling approach and size cut-offs (i.e. single cells versus agglomerates or particle-attached cells). As such, both methods are applicable to different research questions and should be considered complementary.An analysis of the microbial community composition in the aerosols and underlying seawater showed selective aerosolization of certain bacteria taxa. Furthermore, selective growth and a decrease in alpha diversity in the seawater was observed when the mesocosm experiments were operated in a closed mode (meaning that the seawater was not exchanged over the duration of each experiment), which can however be circumvented by continuously replacing the water in the mesocosm.Ambient measurements of PBAP revealed diurnal variations with a peak during the early morning hours that was correlated to changes wind speed, wave height, air temperature, relative humidity, latent and sensitive heat flux.
|
|
| 3. |
- Alvarsson, Jesper J.
(författare)
-
Perspectives on wanted and unwanted sounds in outdoor environments : Studies of masking, stress recovery, and speech intelligibility
- 2013
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- An acoustic environment contains sounds from various sound sources, some generally perceived as wanted, others as unwanted. This thesis examines the effects of wanted and unwanted sounds in acoustic environments, with regard to masking, stress recovery, and speech intelligibility.In urban settings, masking of unwanted sounds by sounds from water structures has been suggested as a way to improve the acoustic environment. However, Study I showed that the unwanted (road traffic) sound was better at masking the wanted (water) sound than vice versa, thus indicating that masking of unwanted sounds with sounds from water structures may prove difficult. Also, predictions by a partial loudness model of the auditory periphery overestimated the effect of masking, indicating that centrally located informational masking processes contribute to the effect. Some environments have also been shown to impair stress recovery; however studies using only auditory stimuli is lacking. Study II showed that a wanted (nature) sound improve stress recovery compared to unwanted (road traffic, ambient) sounds. This suggests that the acoustic environment influences stress recovery and that wanted sounds may facilitate stress recovery compared to unwanted sounds. An additional effect of unwanted sounds is impeded speech communication, commonly measured with speech intelligibility models. Study III showed that speech intelligibility starts to be negatively affected when the unwanted (aircraft sound) masker have equal or higher sound pressure level as the speech sound. Three models of speech intelligibility (speech intelligibility index, partial loudness and signal–to–noise ratio) predicted this effect well, with a slight disadvantage for the signal–to–noise ratio model. Together, Study I and III suggests that the partial loudness model is useful for determining effects of wanted and unwanted sounds in outdoor acoustic environments where variations in sound pressure level are large. But, in environments with large variations in other sound characteristics, models containing predictions of central processes would likely produce better results.The thesis concludes that wanted and unwanted characteristics of sounds in acoustic environments affect masking, stress recovery, and speech intelligibility, and that auditory perception models can predict these effects.
|
|
| 4. |
- Axelsson, Östen, 1971-
(författare)
-
Aesthetic Appreciation Explicated
- 2011
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The present doctoral thesis outlines a new model in psychological aesthetics, named the Information-Load Model. This model asserts that aesthetic appreciation is grounded in the relationship between the amount of information of stimuli and people’s capacity to process this information. This relationship results in information load, which in turn creates emotional responses to stimuli. Aesthetic appreciation corresponds to an optimal degree of information load. Initially, the optimal degree is relatively low. As an individual learns to master information in a domain (e.g., photography), the degree of information load, which corresponds to aesthetic appreciation, increases. The present doctoral thesis is based on three empirical papers that explored what factors determine aesthetic appreciation of photographs and soundscapes. Experiment 1 of Paper I involved 34 psychology undergraduates and 564 photographs of various motifs. It resulted in a set of 189 adjectives related to the degree of aesthetic appreciation of photographs. The subsequent experiments employed attribute scales that were derived from this set of adjectives. In Experiment 2 of Paper I, 100 university students scaled 50 photographs on 141 attribute scales. Similarly, in Paper II, 100 university students scaled 50 soundscapes on 116 attribute scales. In Paper III, 10 psychology undergraduates and 5 photo professionals scaled 32 photographs on 27 attribute scales. To explore the underlying structure of the data sets, they were subjected to Multidimensional Scaling and Principal Components Analyses. Four general components, related to aesthetic appreciation, were found: Familiarity, Hedonic Tone, Expressiveness, and Uncertainty. These components result from the higher-order latent factor Information Load that underlies aesthetic appreciation.
|
|
| 5. |
- Behar, Etienne
(författare)
-
Solar Wind Dynamics within The Atmosphere of comet 67P/Churyumov-Gerasimenko
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, we explore the dynamics of the solar wind as it perme-ates and flows through a tenuous cometary atmosphere, with a focuson the interaction observed at comet 67P/Churyumov–Gerasimenko.Seven comets had already been visited by nine different probes when the European spacecraft Rosetta reached comet Churyumov–Gerasimenko in August 2014. The mission was however the first to orbit its host comet, which it did for a total duration of more than two years, corre-sponding to a large part of the comet’s orbit around the Sun. This en-abled to study how the dynamics of the plasma environment evolvedas the comet itself was transformed from one of the smallest obstaclesto the solar wind in the Solar System when far away from the Sun, toa well-established magnetosphere at perihelion.Most of our efforts tackle the early part of this transformation, when the creation of new-born cometary ions starts to induce significant disturbances to the incident flow. During this stage, a kinetic descrip-tion of the interaction is necessary, as the system of interest cannot be reduced to a hydrodynamic problem. This contrasts with the situation closer to the Sun, where a fluid treatment can be used, at Churyumov–Gerasimenko as well as at previously visited comets.Rosetta was not a mission dedicated to plasma studies, however. It directly translates into a limited spatial coverage of the cometary plasma environment, which by its nature extends over several spatial scales. An approach solely based on the analysis of in-situ data cannot properly address the major questions on the nature and physics of the plasma environment of Churyumov–Gerasimenko. This thesis there-fore largely exploits the experimental–analytical–numerical triad of approaches. In Chapters 3 and 4 we propose simple models of the ion dynamics and of the cometary plasma environment, and these are tested against experimental and numerical data. Used together,they give a global description of the solar wind ion dynamics through the cometary atmosphere, that we explore in the 2-dimensional and 3-dimensional cases (Chapter 5). In Chapter 6, we propose a view onthe interaction and its fluid aspects when closer to the Sun.
|
|
| 6. |
- Bredthauer, Andreas, 1977-
(författare)
-
Tensionless Strings and Supersymmetric Sigma Models : Aspects of the Target Space Geometry
- 2006
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, two aspects of string theory are discussed, tensionless strings and supersymmetric sigma models.The equivalent to a massless particle in string theory is a tensionless string. Even almost 30 years after it was first mentioned, it is still quite poorly understood. We discuss how tensionless strings give rise to exact solutions to supergravity and solve closed tensionless string theory in the ten dimensional maximally supersymmetric plane wave background, a contraction of AdS(5)xS(5) where tensionless strings are of great interest due to their proposed relation to higher spin gauge theory via the AdS/CFT correspondence.For a sigma model, the amount of supersymmetry on its worldsheet restricts the geometry of the target space. For N=(2,2) supersymmetry, for example, the target space has to be bi-hermitian. Recently, with generalized complex geometry, a new mathematical framework was developed that is especially suited to discuss the target space geometry of sigma models in a Hamiltonian formulation. Bi-hermitian geometry is so-called generalized Kähler geometry but the relation is involved. We discuss various amounts of supersymmetry in phase space and show that this relation can be established by considering the equivalence between the Hamilton and Lagrange formulation of the sigma model. In the study of generalized supersymmetric sigma models, we find objects that favor a geometrical interpretation beyond generalized complex geometry.
|
|
| 7. |
- Cornell Kärnekull, Stina, 1985-
(författare)
-
Auditory and Olfactory Abilities in Blind and Sighted Individuals : More Similarities than Differences
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Blind individuals face various challenges in everyday life because of the lack of visual input. However, since they need to rely on the non-visual senses for everyday tasks, for instance, when navigating the environment, the question has been raised as to whether perceptual and cognitive abilities in these senses may be enhanced. This question has mainly been addressed for auditory and tactile abilities, whereas there is considerably less research into the chemical senses, such as olfaction. However, to determine whether blindness has general effects, different senses and types of tasks should be studied, preferably in one and the same study. Therefore, throughout this thesis, analogous auditory and olfactory tasks that varied in cognitive complexity were studied. In Study I, absolute thresholds, discrimination, identification, episodic recognition (i.e., after a short retention interval), metacognition, and self-reported imagery ability were assessed in early blind, late blind, and sighted participants. The only objective measure on which the blind and sighted clearly differed was the auditory episodic recognition task. The fact that early blind but not late blind participants displayed better memory than the sighted suggested that the onset age of blindness may be important for whether this ability becomes enhanced following blindness. Furthermore, the early blind participants rated their auditory imagery ability higher than the sighted, whereas both early and late blind participants rated their olfactory imagery ability higher than the sighted. In Study II, the participants from Study I were followed up after more than a year and retested on auditory and olfactory episodic recognition and identification. This time, the early blind displayed no advantage over the sighted, suggesting that the influence of blindness on auditory memory may be modulated by the length of the retention interval. Moreover, in line with Study I, identification of sounds and odors was similar in the three groups. In Study III, early blind and sighted participants were examined for potential differences in autobiographical memory as evoked by sounds and odors, respectively. Blindness did not influence the reminiscence bumps (i.e., memory peaks in certain age intervals) or have any clear impact on the number of retrieved sound- or odor-evoked memories. Taken together, the present findings indicate that blindness has no general influence across tasks or sensory modalities. Rather, specific auditory abilities, such as episodic memory, may be enhanced in blind individuals, although such effects may depend on both the onset age of blindness and the length of the retention interval. In conclusion, for most perceptual and cognitive abilities examined, performance seemed unaffected by blindness.
|
|
| 8. |
- Dawidson, Karin E. K., 1975-
(författare)
-
Property fragmentation : Redistribution of land and housing during the Romanian democratisation process
- 2004
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the context of democratisation in the early 1990s, the governments in Central and East Europe (CEE) had to decide how to deal with property that had been confiscated under state socialism. Nationalised housing and collectivised land were to a varying extent returned to former owners and their heirs by means of restitution, as well as being distributed to other citizens who were in possession of the users’ rights to such properties. This thesis examines the spatial impacts, in terms of ownership patterns, of the way the redistribution of nationalised housing and collectivised land has been dealt with politically and at the local level in post-socialist Romania. It also locates the Romanian property reforms in relation to those of the rest of CEE. The impact of political directives on the property redistribution is analysed in relation to both structural influences, such as democratisation and antecedent property regimes, and implementation patterns in varied place-contexts. The thesis demonstrates that restitution was stifled due to disagreements between leftist and rightist political blocs, with the latter arguing for restitution whilst their opponents wrote the first restitution laws. A re-privatisation law allowed for the public sale of nationalised housing to tenants and thereby blocked the implementation of a restitution law, thus constituting a dilemma for constitutional democracy. In liberal place-contexts in West Romania, these obstacles to housing restitution were in part avoided. By contrast, land restitution was most widespread in the east, a stronghold of the left. This was because the legislation gives priority to restitution in areas of this kind, where smaller land-holdings dominated prior to 1945. The left-wing government pursued an electoral strategy of distributing small properties to a large number of citizens, and to current users in particular. This resulted in a fragmentation of historical property.
|
|
| 9. |
- Ekdahl, Christer, 1962-
(författare)
-
Infective Endocarditis : aspects of pathophysiology, epidemiology, management and prognosis
- 2008
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Infective endocarditis (IE) is a rare but complex disease that is fatal if untreated. With a modern combination of antimicrobial therapy and heart valve surgery, mortality is still 10-20 %. The structure of the endocarditis vegetation impedes the penetration of phagocytic cells such as monocytes and granulocytes. This leads to high bacterial counts inside the vegetation and the need for long treatment courses with a combination of intravenously administered bactericidal antibiotics.The aim of this thesis was to study the changes in epidemiology, management, and mortality at our hospital between 1980 and 2001, and to identify prognostic factors associated with mortality. To assess the issue of referral bias, differences between referred episodes and episodes from our local community were studied. Additional aims were to study the occurrence of the pro-chemotactic cytokines IL-8 and TNF-α in heart valves and vegetations during the active phase of IE, and to study the effect of the glycopeptide antibiotic vancomycin in dense staphylococcal cultures in vitro. As it is a rare and complex disease, management of IE is usually complicated for non-specialists. For this reason a computerised decision support system for IE was developed and evaluated.Between 1980 and 2001, the occurrence of Staphylococcus aureus IE and the use of early heart valve surgery increased significantly, regardless of whether the episodes were referred or of local origin. Glycopeptide antibiotics, mainly vancomycin, were used more frequently, especially among referred patients. Referred patients were younger, predominantly male, had more complications, and received surgical treatment more often than patients from our local community. The reason for the lower frequency of female patients in the referral cohort cannot be explained by more comorbidity or fewer complications. The differences between referred and local episodes seen in our study highlight the need for assessment and adjustment for referral bias in IE studies (Paper I).In six patients who needed early heart valve surgery, the largest numbers of IL-8-containing cells, and the greatest amount of inflammation, were seen in patients with short preoperative antimicrobial treatment courses. No such relationships were seen with respect to TNF-α-containing cells. The IL-8-containing cells and the inflammatory cells were predominantly scattered in the heart valve stroma or in the margin of the vegetation (Paper II). The primary effect of IL-8 is to stimulate chemotaxis of polymorphonuclear neutrophil granulocytes. This indicates that there is no deficiency of IL-8 in the area close to the vegetation as a cause of the localised agranulocytosis often present inside the vegetation.Our study revealed a need for computerised decision support systems (DSSs) in the field of IE, but to be used in clinical practice these DSSs need be part of knowledge bases covering larger domains (Paper IV). Some of our initial ideas described in Paper III, especially the use of Internet technology and the combination of rule-based advice and explanatory hypertext, will probably be included in these knowledge bases.In vitro, there is a rapid reduction of free vancomycin in broth containing dense staphylococcal cultures. Consequently, there is a simultaneous increase in broth MICs, particularly in high inocula, which is not caused by a development of resistance (Paper V). These findings need further evaluation in vivo, but indicate that the dosing regimen of vancomycin is of particular importance in staphylococcal infections with dense inocula, e.g. infective endocarditis.Diabetes mellitus and moderate to severe heart failure were independent risk factors for 6-month mortality in left-sided, Duke definite IE episodes, regardless of referral or local origin of the episodes. Early heart valve surgery had a positive impact on the 6-month mortality in the referral cohort of episodes, which may be due to referral bias (Paper VI).
|
|
| 10. |
- Engberg, Anna E., 1982-
(författare)
-
Biomaterials and Hemocompatibility
- 2010
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Biomaterials are commonly used in the medical clinic today; however, artificial materials can activate the cascade systems in the blood (complement-, coagulation-, contact- and fibrinolytic systems) as well as the platelets to various degrees. When an artificial surface comes in contact with blood, plasma proteins will be adsorbed to the surface within seconds. The composition of the layer of proteins differs between materials and is crucial for the hemocompatibility of the material.This thesis includes five projects.In Paper I the anticoagulants heparin and the thrombin inhibitor hirudin were evaluated in a whole blood model. Hirudin was found to be superior to low dose heparin since it did not affect the activation of the complement system nor the leukocytes. The most interesting observation was that expression of TF was seen on surface-attached monocytes in hirudin- treated blood but not heparin blood.In Paper II peptides from the streptococcal M-protein, which has affinity for the human complement inhibitor C4BP, were attached to a polymeric surface. When being exposed to blood the endogenous complement regulator was enriched at the surface of the material, via the M-peptides. With this new approach we created a self-regulatory surface, showing significant lowered material-induced complement activation.In Paper III apyrase, an enzyme which hydrolyzes nucleoside ATP and ADP, was immobilized on a polymer surface. Lower platelet activation and platelet-induced coagulation activation was seen for the apyrase-coated surface compared to control surfaces after exposure to whole human blood, due to the enzymes capability to degrade ADP released from activated platelets.In Paper IV and V we synthesized an array of polymeric materials which were characterized regarding physical-chemical properties, adsorption of plasma proteins, and hemocompatibility. The polymers showed widely heterogeneous protein adsorption. Furthermore, when the polymers were exposed to whole blood, two of the materials showed superior hemocompatibility (monitored as complement- and coagulation activation), compared to the reference poly(vinyl chloride).
|
|
