| 1. |
- Adawi, Tom W., 1970-
(författare)
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From Branes to Brains : On M-theory and Understanding Thermodynamics
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is concerned with research in both physics and physics education, and is divided into two parts.Part IString theory has been the leading candidate over the past few years for a theory that unifies all the fundamental forces of nature. The fundamental objects are one-dimensional strings whose vibrational modes should correspond to the usual elementary particles. However, the recent discovery of the profound role played by extended solitonic objects in string theory, referred to as p-branes, has questioned the foundational position of the string itself. A key ingredient in these developments is the notion of duality, a symmetry which provides a handle on non-perturbative physics. As a result, all five string theories, as well as eleven-dimensional supergravity, are but special limits of a conjectural theory, referred to as M-theory. In this part of the thesis, various aspects of p-branes with relevance for M-theory are investigated. Special emphasis is given to the interpretation of p-branes as solitons. Furthermore, some of the features of the superembedding approach to describe p-brane dynamics are examined.Part IIThere is now a consensus among educational researchers that it is essential to gain a better understanding of how people understand key concepts in physics in order to improve teaching and learning in physics. This part of the thesis reports on a phenomenographic study investigating the qualitatively different ways in which lay adults, taking an introductory overview course in physics, understand the concepts of heat and temperature. Implications for teaching the topics in higher education forms an essential component of the analysis. This is followed by a theoretical component that draws on the empirical analysis as a contribution to the development of the notion of context in phenomenographic research.
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| 2. |
- Adsten, Monika, 1972-
(författare)
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Solar Thermal Collectors at High Latitudes : Design and performance of non-tracking concentrators
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Solar thermal collectors at high latitudes have been studied, with emphasis on concentrating collectors. A novel design of concentrating collector, the Maximum Reflector Collector (MaReCo), especially designed for high latitudes, has been investigated optically and thermally. The MaReCo is an asymmetrical compound parabolic concentrator with a bi-facial absorber. The collector can be adapted to various installation conditions, for example stand-alone, roof- or wall mounted. MaReCo prototypes have been built and outdoor-tested. The evaluation showed that all types work as expected and that the highest annually delivered energy output, 340 kWh/m2, is found for the roof MaReCo. A study of the heat-losses from the stand-alone MaReCo lead to the conclusion that teflon transparent insulation should be placed around the absorber, which decreases the U-value by about 30%. A method was developed to theoretically study the projected radiation distribution incident on the MaReCo bi-facial absorber. The study showed that the geometry of the collectors could be improved by slight changes in the acceptance intervals. It also indicated that the MaReCo design concept could be used also at mid-European latitudes if the geometry is changed. A novel method was used to perform outdoor measurements of the distribution of concentrated light on the absorber and then to calculate the annually collected zero-loss energy, Ea,corr, together with the annual optical efficiency factor. A study using this method indicated that the absorber should be mounted along the 20º optical axis instead of along the 65º optical axis, which leads to an increase of about 20% in Ea,corr. The same absorber mounting is suggested from heat loss measurements. The Ea,corr at 20º absorber mounting angle can be increased by 5% if the absorber fin thickness is changed from 0.5 to 1 mm and by 13% if two 71.5 mm wide fins are used instead of one that is 143 mm wide. If the Ea,corr for the standard stand-alone MaReCo with 143 mm wide absorber mounted at 65º is compared to that of a collector with a 71.5 mm wide absorber mounted at 20º, the theoretical increase is 38%.
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| 3. |
- Ahlgren, Johan, 1960-
(författare)
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Studies on Prediction of Axillary Lymph Node Status in Invasive Breast Cancer
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Breast cancer is the most common malignancy among females in Sweden. Axillary lymph-node dissection is a standard procedure in the management of breast cancer, aiming at obtaining prognostic information for adjuvant therapy decisions. Axillary dissection entails considerable morbidity. The aims of this study were to establish more selective surgical approaches and to investigate angiogenesis, a potential predictor for lymph-node metastases and prognosis.Clinical nodal status, tumour size and S-phase were associated with nodal metastases in cohort of 1145 women. The proportion of nodal metastases was 13% in the subgroup with the lowest risk.In a study from two registries, 675 and 1035 breast cancers ≤10 mm diagnosed by screening mammography had nodal metastases in 6,5% and 7%, respectively. Clinically detected cancers had a risk of 16% and 14%, respectively.In a study on 415 women, a 5-node biopsy of the axilla had a sensitivity of 97,3% and a false negative rate of 2,7% in comparison with axillary dissection.Six sections from 21 breast cancers were analysed for microvessel density (MVD). The inter-section variation contributed more to the total variance than inter-tumour variation, 45,0% and 37,3%, respectively.In a cohort of 315 women, breast cancers with high MVD more frequently had p53 mutations (27,1%) compared with cases with low MVD (18,4%). This difference was not statistically significant (p=0,075). p53 mutations were associated with a worse outcome, whereas MVD was not.In conclusion, women with screening detected ≤10 mm breast cancers have a low risk of lymph node metastases and some may not need axillary dissection in the future. The 5-node biopsy could be an alternative to axillary dissection. MVD is associated with methodological weaknesses and routine use is not recommended.
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| 4. |
- Akyuz, Mose, 1972-
(författare)
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Positive streamer discharges in air and along insulating surfaces: experiment and simulation
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The power quality of modern society relies on the electrical properties of the dielectric insulators used in the power industry. Much research work has been conducted with an aim to understand and predict the insulating behaviour of such materials under different kinds of atmospheric conditions, but still there are many unsolved problems. In particular, there is a lack of knowledge concerning the electrohydrodynamic and electrophysical processes at the insulator surface and the surrounding medium. No detailed knowledge exists at present of the processes governing the development of electrical discharges along the surface of insulators.With an aim to enhance the knowledge in this field in general and on the electrical performance of outdoor insulators in particular a detailed study of the positive streamer discharges in air and along dielectric surfaces was conducted. The study was also extended to gain more knowledge on the water drop initiated electrical discharges in air and the attachment of natural lightning flashes to a Franklin conductor.In the first phase, the study was focused on positive streamer discharges propagating in air. The spatial distribution of the charge of a branched streamer discharge was obtained and the charge contained in a single streamer branch was quantified. In the second phase measurements and simulations of streamer discharges propagating along insulating surfaces were conducted with an aim to understand how the insulating surfaces interact with streamer discharges. In addition to quantifying the parameters of streamer discharges propagating along insulating surfaces, the results of these studies made it possible to separate and quantify the effects of the dielectric constant and the surface properties on the streamer discharges. In the third phase a comprehensive computer algorithm was developed to simulate 3-dimensional propagation of positive streamer discharges in air and along dielectric surfaces taking into account the branching effect. The conditions necessary for the initiation of streamer discharges were applied to obtain the minimum strength of the background electric field required to initiate electrical discharges in the presence of water drops. In particular the study provided an explanation of how lightning flashes are initiated in thunderclouds in background electric fields as low as 200 kV/m. Finally, the study was extended to understand the performance of lightning conductors paying special attention to the influence of conductor radius and the streamer inception criterion.
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| 5. |
- Albinsson, Lars, 1944-
(författare)
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A Palliative Approach to Dementia Care : Leadership and organisation, existential issues and family support
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main purpose of this thesis was to apply the WHO and NHS palliative care approach to dementia care. Thirty-one staff-members in mid-Sweden (studies I and II) and 20 next-of- kin (study IV) were interviewed. In study III, 316 staff-members from dementia care and 121 staff-members from palliative cancer care responded to a questionnaire about family support. The interviews were tape-recorded and analysed with a qualitative phenomenographic (I and II) and a hermeneutic approach (IV). The questionnaires (III) were analysed using qualitative and quantitative content analysis.The staff-members stated almost unanimously that daily leadership was lacking, and consequently clear goal formulations and care planning were rare (I). Proper teamwork between the doctor and the staff who worked on a daily basis with the patients was absent (I). With respect to existential issues, education and staff discussions were lacking (II). The staff were at a loss concerning how to deal with these issues. Nevertheless, these issues are central to family-members who have to deal with an existential crisis (IV). Important questions emerged about obligation and guilt, faithfulness, responsibility, and paying back what you once received. Existential isolation could be identified e.g. in the reversal of roles experienced as "being a parent to your parent" and in the burden of "visiting a living dead person". There were no routines for bereavement visits. The type of support suggested for dementia family members is partly similar to support in palliative cancer care, but it also differs in other respects such as feelings of guilt because the early signs of the disease are misunderstood, the need for respite because of the long trajectory of dementia diseases, and the occurrence of anticipatory grief because in the late phase family members can no longer make any contact at all with the patient (III).A palliative approach can improve the quality of life for the dementia patient and for the family. It can be used as a basis for a clear goal formulation. Some of the suggestions listed in this thesis for improving the quality of care are more a reflection of the need for a change in attitudes rather than the need for substantial budget increases.
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| 6. |
- Alm, Mikael, 1973-
(författare)
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Kungsord i elfte timmen : Språk och självbild i det gustavianska enväldets legitimitetskamp 1772–1809
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with the language and image of late Swedish absolutism. The sources used are royal medals and royal speeches and ceremonies at the Diets. The images are analysed as linguistic constructions, made up by a framework of concepts articulated in words, symbols and ceremonies around the kings. The essential argument is that during the late eighteenth century, European absolute monarchy suffered a severe legitimation crisis that had its origins at a discursive level. The political discourse changed: old conceptions and attitudes were revised, and new ones were established. Faced with these changing prerequisites for legitimacy, the absolute monarchs had increasing difficulty to master the political vocabulary; as traditional political concepts successively lost their potential to legitimise, the new concepts increasingly challenged the existing political order. The investigation consists of three analytical parts. The first part focuses on the language and image of Gustaf III. The second part focuses on the reception of the royal images and the discursive expressions among the subjects during the entire period (1772–1809). Attention is also paid to the repressive machinery of Gustavian absolutism as an important part of the struggle for discursive authority. The third part focuses on the language and image of Gustaf IV Adolf. The results show fundamental changes over time in the struggles for legitimacy, referred to as a movement from a primarily communicative strategy during the reign of Gustaf III, to a primarily repressive strategy during the reign of Gustaf IV Adolf. These changes are connected to the escalating discursive conflicts shown in the intermediate part, and are essential for the understanding of the final fall of Swedish absolutism in 1809.
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| 7. |
- Alsmark, Cecilia
(författare)
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Comparative Genomics of Obligate and Facultative Intracellular Parasites
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The α-proteobacteria Rickettsia prowazekii and Bartonella henselae are the causative agents of epidemic typhus and cat scratch disease respectively. Whereas R. prowazekii is an obligate intracellular parasite, B. henselae can live and proliferate both outside and inside the eukaryotic host cell. Besides the obvious medical interest to identify the complete gene set of two human pathogens, their genome sequences are also important for the study of evolutionary processes. Both R. prowazekii and B. henselae have small genomes, but their last common ancestor of these two bacteria was most likely a free-living organism with a substantially larger genome.The aim of this thesis is to compare the complete genomes of R. prowazekii and B. henselae and to decipher the evolutionary processes leading to the adaptation to an intracellular lifestyle. The working hypothesis was that the facultative intracellular B. henselae is an intermediate between a free living bacteria and the obligate R. prowazekii, which is corroborated. B. henselae has a broader biosynthetic repertoire than R. prowazekii, including the presence of genes for glycolysis and de novo biosynthesis of purines and pyrimidines. However, both bacteria have reduced gene sets for biosynthesis of amino acids and cofactors compared to free-living bacteria.Comparisons of gene order in bacteria reveal that several operons are well conserved between distantly related species. The genome sequences of R. prowazekii and B. henselae show that many of the operons that are usually conserved, are broken and rearranged in these species. One of the mechanisms of reductive evolution include intra-chromosomal recombination between repeated loci. This process expels one of the repeats and cause rearrangements in the gene order of the flanking regions. While the R. prowazekii genome almost completely lack repeated sequences, the B. henselae genome is rich in repeats. These repeats are, however, most often located within regions associated with pathogenicity islands. The higher number of scrambled operons, and the lower number of repeats, in R. prowazekii compared to B. henselae imply that the reductive process has gone further in the former species.
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| 8. |
- Alström, Per
(författare)
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Species Limits and Systematics in Some Passerine Birds
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- I use morphological, vocal, molecular, behavioural, ecological and distributional data to re-evaluate the systematics of three passerine bird groups, the Mirafraassamica complex (bush-larks), the genus Seicercus ("spectacled-warblers"; with emphasis on the the S. burkii complex) and the genus Motacilla (wagtails). Two new species are described: Seicercus soror and Motacilla samveasnae. I propose that the polytypic species M. assamica should be treated as four separate species: M. assamica, M. affinis, M. microptera and M. marionae (it is also remarked that the proper name of the latter is M. erythrocephala). That is primarily supported by vocalisations and mitochondrial DNA. The latter data set also suggests that M. assamica sensu lato is paraphyletic, since M. erythroptera, which is always treated as a separate species, is nested within the M. assamica complex. I propose that the polytypic species S. burkii comprises six sibling species. Some of these are found to breed sympatrically, although mainly or entirely segregated altitudinally. Mitochondrial DNA suggests that the S. burkii complex is non-monophyletic, and also that the divergence of the different taxa is much older than indicated by morphological and vocal data. According to the molecular phylogeny, both the genera Seicercus and its assumed sister genus Phylloscopus are paraphyletic. That is corroborated by independent data. The phylogenetic study of the genus Motacilla reveals incongruence between mitochondrial DNA, nuclear DNA and non-molecular data. I conclude that the nuclear gene tree reflects the organismal phylogeny more faithfully than the mitochondrial gene tree. The latter is likely to have been affected by introgressive hybridisation, possibly also stochastic lineage sorting. The most remarkable result that is strongly supported by both mitochondrial and nuclear DNA is that M. flava is non-monophyletic.
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| 9. |
- Ameur, Yacin, 1972-
(författare)
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Interpolation of Hilbert spaces
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- (i) We prove that intermediate Banach spaces A, B with respect to arbitrary Hilbert couples H, K are exact interpolation iff they are exact K-monotonic, i.e. the condition f0∊A and the inequality K(t,g0;K)≤K(t,f0;H), t>0 imply g0∊B and ||g0||B≤||f0||A (K is Peetre's K-functional). It is well-known that this property is implied by the following: for each ρ>1 there exists an operator T : H→K such that Tf0=g0, and K(t,Tf;K)≤ρK(t,f;H), f∊H0+H1, t>0.Verifying the latter property, it suffices to consider the "diagonal" case where H=K is finite-dimensional. In this case, we construct the relevant operators by a method which allows us to explicitly calculate them. In the strongest form of the theorem, it is shown that the statement remains valid when substituting ρ=1. (ii) A new proof is given to a theorem of W. F. Donoghue which characterizes certain classes of functions whose domain of definition are finite sets, and which are subject to certain matrix inequalities. The result generalizes the classical Löwner theorem on monotone matrix functions, and also yields some information with respect to the finer study of monotone functions of finite order. (iii) It is shown that with respect to a positive concave function ψ there exists a function h, positive and regular on ℝ+ and admitting of analytic continuation to the upper half-plane and having positive imaginary part there, such that h≤ψ≤ 2h. This fact is closely related to a theorem of Foiaş, Ong and Rosenthal, which states that regardless of the choice of a concave function ψ, and a weight λ, the weighted l2-space l2(ψ(λ)) is c-interpolation with respect to the couple (l2,l2(λ)), where we have c≤√2 for the best c. It turns out that c=√2 is best possible in this theorem; a fact which is implicit in the work of G. Sparr. (iv) We give a new proof and new interpretation (based on the work (ii) above) of Donoghue's interpolation theorem; for an intermediate Hilbert space H* to be exact interpolation with respect to a regular Hilbert couple H it is necessary and sufficient that the norm in H* be representable in the form ||f||*= (∫[0,∞] (1+t-1)K2(t,f;H)2dρ(t))1/2 with some positive Radon measure ρ on the compactified half-line [0,∞]. (v) The theorem of W. F. Donoghue (item (ii) above) is extended to interpolation of tensor products. Our result is related to A. Korányi's work on monotone matrix functions of several variables.
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| 10. |
- Amini, Rose-Marie, 1969-
(författare)
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Hodgkin Lymphoma : Studies of Advanced Stages, Relapses and the Relation to Non-Hodgkin Lymphomas
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The relationship between Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) is not entirely elucidated and a clonal relation may be present more often than previously believed. Mechanisms of tumour progression and resistance to therapy are poorly understood.Between 1974 and 1994 all individuals in Sweden with both HL and NHL were identified. Thirty-two cases were studied using clinical, histopathological and immunohistochemical methods. The second lymphoma often appeared in an aggressive clinical form and a significant correlation between the expression of p53 and LMP-1 in the first and second lymphoma was demonstrated.The treatment outcome for 307 patients with advanced stages of HL, in an unselected population was in accordance with the treatment results of large centres world-wide. Some patients were successfully selected for a shorter chemotherapy-regimen without inferior treatment results.In 124 patients with relapse, the survival of those primarily treated with radiotherapy according to the National guidelines was in accordance with the survival of patients of initially advanced stages. A worse outcome was found for those who received both chemotherapy and radiotherapy initially, probably because of a higher frequency of bulky disease in this group. Immunohistochemical analysis of the tumour suppressor protein p53 and retinoblastoma protein (Rb) of paired samples at diagnosis and at relapse in 81 patients did not reveal any specific staining pattern affecting survival.A novel B-cell line (U-2932) was established from a patient with a diffuse large B-cell lymphoma previously treated for advanced stage and subsequent relapses of HL. An identical rearranged IgH gene was demonstrated in tumour cells from the patient and in U-2932. A p53 point mutation was detected and over-expression of the p53 protein was found. A complex karyotype with high-level amplifications of the chromosomal regions 18q21 and 3q27, i.e. the loci for bcl-2 and bcl-6 were demonstrated.
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