| 1. |
- Gunnarsson, Gunnar, 1976-
(author)
-
Survival patterns and density-dependent processes in breeding mallards Anas platyrhynchos
- 2007
-
Doctoral thesis (other academic/artistic)abstract
- Measuring and assessing vital rates such as births and deaths are prerequisites for understanding population dynamics. Vital rates may be affected by the density of individuals, even though the importance of density dependence on population dynamics has been debated for a long time. The mallard Anas platyrhynchos is one of the foremost game species in the Holarctic, with millions of birds in hunters’ bags annually. Still, basic knowledge about regulation of mallards’ vital rates is poor, and experimental studies on this topic are rare.In this thesis I have studied survival patterns and density dependence in mallards breeding in Sweden and Finland. Long-term ringing data from both countries were analysed for mortality patterns and causation, as well as for e.g. survival rate estimation. Most of the studies were, though, experiments run over two years involving manipulations of the density of nests, broods and/or adults, in southern and northern Sweden, comprising different biotic regions. Common response variables were survival of nests, ducklings and hens, mainly analysed with program MARK.About 90% of the recovered mallards in Finland and Sweden were hunting kills. However, survival rates were high, ranging from 0.66 to 0.81 for most groups (sex*age). The generality of density dependence was evident since such processes were detected in all studies. Consequently, depredation rate was higher in high nest density compared to low nest density. Survival of ducklings was density-dependent in both boreal and nemoral biotic regions, with food limitation being evident in the former region but not in the latter. In spite of their generality, density-dependent patterns varied within as well between years, and for nest predation rates also between landscape types.The findings about density dependence in breeding mallards in this thesis are novel since they are based on experiments. They are potentially of general interest for management because they embrace a variety of lakes in two geographically distant areas, each being representative for large temperate areas in the northern hemisphere. Detection of density dependence at the local scale may be important at larger scales, too, following the principle of ‘ideal preemptive distribution’ in a source-sink dynamic system.
|
|
| 2. |
- Gunnarsson, Gunnar
(author)
-
Survival patterns and density-dependent processes in breeding mallards Anas platyrhynchos
- 2007
-
Doctoral thesis (pop. science, debate, etc.)abstract
- Measuring and assessing vital rates such as births and deaths are prerequisites for understanding population dynamics. Vital rates may be affected by the density of individuals, even though the importance of density dependence on population dynamics has been debated for a long time. The mallard Anas platyrhynchos is one of the foremost game species in the Holarctic, with millions of birds in hunters’ bags annually. Still, basic knowledge about regulation of mallards’ vital rates is poor, and experimental studies on this topic are rare. In this thesis I have studied survival patterns and density dependence in mallards breeding in Sweden and Finland. Long-term ringing data from both countries were analysed for mortality patterns and causation, as well as for e.g. survival rate estimation. Most of the studies were, though, experiments run over two years involving manipulations of the density of nests, broods and/or adults, in southern and northern Sweden, comprising different biotic regions. Common response variables were survival of nests, ducklings and hens, mainly analysed with program MARK. About 90% of the recovered mallards in Finland and Sweden were hunting kills. However, survival rates were high, ranging from 0.66 to 0.81 for most groups (sex*age). The generality of density dependence was evident since such processes were detected in all studies. Consequently, depredation rate was higher in high nest density compared to low nest density. Survival of ducklings was density-dependent in both boreal and nemoral biotic regions, with food limitation being evident in the former region but not in the latter. In spite of their generality, density-dependent patterns varied within as well between years, and for nest predation rates also between landscape types. The findings about density dependence in breeding mallards in this thesis are novel since they are based on experiments. They are potentially of general interest for management because they embrace a variety of lakes in two geographically distant areas, eachbeing representative for large temperate areas in the northern hemisphere. Detection of density dependence at the local scale may be important at larger scales, too, following the principle of ‘ideal preemptive distribution’ in a source-sink dynamic system.
|
|
| 3. |
- Hjalmarson, Jenny, 1974-
(author)
-
Ergonomics at Home : Design for Safe Living and Home Care
- 2014
-
Doctoral thesis (other academic/artistic)abstract
- The home should represent safety and security for the person who lives there, and this is an important factor for independence and autonomy in very old age. With aging populations, the needs for long-term care increase, care provided by spouses and/or from the growing home care sector. Injuries among these groups are common.In this study, an ergonomics perspective was applied in the analysis of some basic daily activities performed by old persons and by home care workers, assisting.The postures and movements of home care staff assisting at toilet visits, and transferring persons from wheelchair to toilet, were measured and analysed.Some daily activities related to making food and washing clothes, performed by a group of persons between the age of 75 and 100, were measured and analysed.The task of getting up from the floor – on your own and with the help of a walker equipped with a lifting device – was analysed with the help of older persons and nursing staff. The design was built on the knowledge gained from analysing how older people get up from floor.Requirements for access with a four-wheeled walker in the local built environment were investigated.Observations were made with the help of video recording. Postures were recorded with the CUELA measurement system. The VIDAR ergonomics evaluation instrument was used to register the participants’ experiences of discomfort and pain during getting up from the floor with or without the walker with a lifting device. Structured interviews were used to find out about older peoples’ experience of using the four-wheel walker.It is concluded that ageing at home requires improved architectural and technical bathroom design and improved access in the local built environment.
|
|
| 4. |
- Lundberg, Arvid, 1985-
(author)
-
Openness as Political Culture : The Arab Spring and the Jordanian Protest Movements
- 2018
-
Doctoral thesis (other academic/artistic)abstract
- This study is an exploration of the origins of the Arab Spring in Jordan and across the region. Based on ethnographic fieldwork among the leadership of the Jordanian protest movements, it suggests a new way of understanding why these movements fell apart. A recurrent theme in accounts of the political movements that emerged in Jordan and the Arab world more generally in 2011 is that the unity that initially appeared on streets and squares never transformed into a viable coalition but instead dissolved. A common way to understand why the Arab Spring’s promise of a less authoritarian society was not fulfilled is to look at the center of a political system and explain why it did not become more democratic. These explanations depend on an alternative that we know only through our counterfactual imagination: a united opposition capable of bringing about a democratic system. Instead of imagining a united opposition and explaining why it was not realized, the thesis starts with the fact that the Jordanian opposition was deeply fragmented, but that there were attempts to counter this fragmentation by coordinating and specifying its demands. These attempts fell apart due to something more general than ideological, ethnic or religious divisions within the Jordanian opposition. They were based on a way of conducting politics that was uncommon among the leadership of the protest movements as well as among their opponents. These attempts were characterized by an emphasis on political ideas and programs rather than patronage and by an orientation toward political dialogue, which some Jordanians described in terms of “infitāḥ” (openness) and contrasted with a more polemical form of politics. This ethnographic study puts this more unusual form of politics into sharper relief and shows how it was rooted in political practices and values as well as comparable types of education and social life. This allows us to see how democratization is a movement that is not only political but also cultural, which takes shape in political activism, education and social life.
|
|
| 5. |
- Lundberg, H Johan
(author)
-
On endovascular methods for cell transplantation : exploring the selective intra-arterial and trans-vessel wall routes
- 2011
-
Doctoral thesis (other academic/artistic)abstract
- Background: Cell based transplantation methods are a pivotal part of the emerging field of regenerative medicine. These transplantation methods could possible produce curative treatments where, previously, expectations of such feats were low. Diseases for which treatments are evaluated are in such diverging physiological systems as e.g. the CNS with ischemic or traumatic injuries, the endocrine system with type I diabetes mellitus, or musculo-skeletal system with dystrophies, hematological system with leukemia and cardio-vascular system with ischemic heart disease among others. Transplantation methods for cells span from open surgical/percutaneous, over intravenous, to specific intra-arterial methods. The method for delivery of cells is in fact an important part of the translation of cell based therapies to clinical practice. With that said, the use of endovascular techniques opens attractive routes of transplantation that needs to be thoroughly studied in order to achieve maximum efficacy. Methods: We have utilized a model of traumatic brain injury in the rat where cell transplantations have been performed by selective intra-arterial methods and compared to intravenous administration. Analysis of engraftment has been performed by immunohistochemistry and cell characterization has been performed by microarray and RT-qPCR. Further, we have developed the Extroducer catheter system, a “nano”- catheter aimed for trans-vessel wall technique passage, in simulator, ex vivo, in vivo in rat and with full clinical integration in rabbit and swine. Long term follow-up studies have been performed both in rat (14 days) and rabbit (5, 30 and 80 days). Results and Conclusions: We first show that selective intra-arterial methods increase engraftment levels up to fifteen-folds higher compared to intravenous controls. However, not all cell systems are found to be optimal for intra-luminal transplantation methods. Some of the factors limiting engraftment were thus explored within the cell systems themselves. These findings indicated that lack of engraftment might be dependent on integrin expression and endothelial interactions. For cells that lack the capacity of diapedesis and especially for more specific niche cell systems, such as insulin producing cells in the pancreas, the Extroducer can create direct parenchymal access via the endovascular route. Thus, the Extroducer system, developed within this thesis, offers a working channel between the proximal end of an endovascular catheter and the parenchyma of any organ of the body. Development and testing verified integration with clinical routine catheters. No long term adverse events were observed in the rat or the rabbit following the trans-vessel wall passage. In conclusion, endovascular intervention can provide a number of conceptually different methods for cell transplantation.
|
|
| 6. |
- Lundberg, Johan, 1966-
(author)
-
Local government expenditures and regional growth in Sweden
- 2001
-
Doctoral thesis (other academic/artistic)abstract
- This thesis consists of five papers, which concern expenditure decisions and economic growth within Swedish local government.Paper [1] explores the hypothesis that local fiscal shocks have short run effects on revenue and expenditure decisions made within local government. It is found that although fiscal shocks do not affect local authorities' revenue decisions, they do induce municipalities to change expenditures and financial costs along with short term loans. Local authorities are also found to respond more powerful to unfavorable fiscal shocks (deficit shocks) than to favorable fiscal shocks (surplus shocks).In Paper [2], we study the hypothesis that local (municipal) expenditures, in part, can be explained by regional (county) expenditures. We formulate and estimate a demand model for municipal services that is defined conditional on the county expenditures. The results imply a positive dependency between the provision of county and municipal services. Moreover, the results suggest that the hypothesis of weak separability between the provision of county and municipal services can be rejected. In addition, we cannot reject the hypothesis that the regional expenditures are weakly exogenous in the local expenditure equation.In Paper [3] the existence of spillover between Swedish municipalities in the provision of recreational and cultural services is analyzed. A representative .voter model is derived and the demand for recreational and cultural services is estimated using spatial SUR techniques. The results suggest a negative relationship between recreational and cultural expenditures provided by neighboring municipalities, which indicates that these services are substitutes.Paper [4] concerns the regional growth pattern in Sweden by analyzing what factors might determine the growth rate of regional average income levels and the net migration rates. Our results suggest a negative dependence between the initial average income level and the subsequent income growth, which supports the conditional convergence hypothesis. Among other things, we also find that the initial endowments of human capital have a positive effect on subsequent net migration while the initial unemployment rate is found to have a negative impact on net migration.Paper [5] complements the analysis made in Paper [4] by studying which factors determine average income growth and net migration at the local level of government. The conditional convergence hypothesis cannot be rejected. Local government investments are found to have a positive effect on the subsequent net migration while leaving the growth in mean income unaffected. This may indicate that the net migration caused by these investments does not significantly affect the proportion of skilled and unskilled labor.
|
|
| 7. |
- Lundberg, Johan, 1978-
(author)
-
On the Search for High-Energy Neutrinos : Analysis of data from AMANDA-II
- 2008
-
Doctoral thesis (other academic/artistic)abstract
- A search for a diffuse flux of cosmic neutrinos with energies in excess of 1014 eV was performed using two years of AMANDA-II data, collected in 2003 and 2004. A 20% evenly distributed sub-sample of experimental data was used to verify the detector description and the analysis cuts. A very good agreement between this 20% sample and the background simulations was observed. The analysis was optimised for discovery, to a relatively low price in limit setting power. The background estimate for the livetime of the examined 80% sample is 0.035 ± 68% events with an additional 41% systematical uncertainty.The total neutrino flux needed for a 5σ discovery to be made with 50% probability was estimated to 3.4 ∙ 10-7 E-2 GeV s-1 sr-1 cm-2 equally distributed over the three flavours, taking statistical and systematic uncertainties in the background expectation and the signal efficiency into account. No experimental events survived the final discriminator cut. Hence, no ultra-high energy neutrino candidates were found in the examined sample. A 90% upper limit is placed on the total ultra-high energy neutrino flux at 2.8 ∙ 10-7 E-2 GeV s-1 sr-1 cm-2, taking both systematical and statistical uncertainties into account. The energy range in which 90% of the simulated E-2 signal is contained is 2.94 ∙ 1014 eV to 1.54 ∙ 1018 eV (central interval), assuming an equal distribution over the neutrino flavours at the Earth. The final acceptance is distributed as 48% electron neutrinos, 27% muon neutrinos, and 25% tau neutrinos.A set of models for the production of neutrinos in active galactic nuclei that predict spectra deviating from E-2 was excluded.
|
|
| 8. |
- Lundberg, Johan
(author)
-
PET studies of the serotonin transporter in the human brain
- 2006
-
Doctoral thesis (other academic/artistic)abstract
- The serotonin (5-HT) system attracts considerable attention in research on the pathophysiology and drug treatment of neuropsychiatric disorders. The brain imaging technique Positron Emission Tomography (PET) allows for examination of neurotransmission systems in the human brain in vivo. Though suitable radioligands are available for the serotonin 5-HT1A and 5HT2A receptor subtypes, imaging studies of the 5HT transporter (5-HTT), a key target for drug treatment of mood and anxiety disorders, has been limited due to lack of optimal radioligands. In autoradiographic studies on rat and post mortem human brain slices the radioligand 3H-labelled MADAM has been shown to bind specifically in regions known to have high 5-HTT density. The first aim of the present thesis was therefore to evaluate 11C-labelled MADAM for in vivo quantification of 5-HTT in the human brain using PET. The second aim was to apply this method in control subjects and to address questions relevant for the pathophysiology and drug treatment of major depressive disorder (MDD). In the first study, a total of four cynomolgus monkeys were examined. The selectivity and reversibility of [11C]MADAM binding was examined. Pretreatment with citalopram resulted in decreased [11C]MADAM uptake in 5-HTT rich regions. Pretreatment with GBR 12909 and maprotiline did not affect [11C]MADAM uptake, thus confirming that [11C]MADAM binds selectively to the 5-HTT in the primate brain. In the second study [11C]MADAM binding could be described by standard compartment models using an arterial input function. The cerebellum was evaluated as reference region in simplified quantitative approaches showing that the rank order of regional binding potential (BP) values was in good agreement with the rank order reported in binding studies on human brain tissue post mortem. The use of simplified quantitative approaches in clinical studies was thus supported. In the third study the reproducibility of [11C]MADAM binding was studied in a test-retest design tailored to be relevant for future applied studies. Analysis of test-retest data indicate that the reliability of [11C]MADAM binding measurements is good to excellent for averaged regions. The study supports clinical studies also on small regions such as the raphe nuclei, although pooling of data may be required for bilateral regions to improve accuracy. The fourth study examined expression levels of 5-HTT and 5-HT1A receptors in control subjects, i.e. two proteins suggested in mode of action of anti-depressive drugs. A trend towards correlation between [11C]MADAM and [11C]WAY 100635 binding was found in the raphe but not in hippocampus or neocortex. Also, the ratio in the raphe nuclei showed a wide range. This finding suggests that expression of these two proteins may be co-regulated in the raphe nuclei. The wide range for binding ratio represents a possible explanation for the clinical variability in response to antidepressant drug treatment. In the fifth study the use of [11C]MADAM to determine 5-HTT occupancy was examined by comparing 10 mg escitalopram, and 20 mg of the racemate citalopram in a two-way cross over, double blind design. Citalopram gave higher occupancy than escitalopram - although the subjects were given equimolar amounts of S-citalopram, the hypothesised active compound in both citalopram and escitalopram. The hypothesis that the lower response rate of citalopram may in part be dependent on R-citalopram interacting with 5HTT could thus find indirect support. In summary, [11C]MADAM was shown to be a suitable radioligand for quantitative studies of 5-HTT in the living human brain, and can readily be applied for studies on the pathophysiology and pharmacology of neuropsychiatric disorders.
|
|
| 9. |
- Lundberg, Jakob, 1967-
(author)
-
Rethinking Urban Nature : Maintaining Capacity for Ecosystem Service Generation in a Human Dominated World
- 2006
-
Doctoral thesis (other academic/artistic)abstract
- Human action has transformed the major part of the Earth’s ecosystems. A growing human population puts further pressure on dynamic landscapes and resources. Crucially, for the first time in history, most people live in cities and environmental change has become truly global. Developed as part of the sub-global assessments of The Millennium Ecosystem Assessment, this thesis examines anthropogenic effects on our life-support systems, and their altered capacity to generate goods and services of socio-economic value. It incorporates humans into the analysis of ecosystem dynamics and explores new ways to restore, create, and enhance ecosystem services in urban and other fragmented landscapes.The concept of mobile link organisms, i.e. key species that connect habitats and uphold their capacity to generate ecosystem services, is elaborated in relation to ecosystem dynamics and functioning. They are classified into resource, genetic and process linkers (Paper I). One such species, the Eurasian Jay (Garralus glandarius) and its role in oak tree regeneration across habitats, is empirically studied in a park of Stockholm (Paper II). The Jay is found to be pivotal in safeguarding the desired oak dominated landscape but its seed dispersal function requires active management, including of surrounding non-protected habitats. Potentially, a process oriented management approach could reduce costs and vulnerability to disturbances as well as preserve gene flow and diversity on a landscape level. Critical functions for ecosystem resilience performed by mobile links are likely to grow in importance as human impacts increase.The next focus is on ecosystems that are seldom considered in biological conservation and urban green space management. Ecosystem functions and services are identified in three types of culturally maintained land areas: golf courses, residential gardens, and allotments (Paper III). By GIS-assessment, it is established that they amount to 18% of the studied land area in metropolitan Stockholm, i.e. over twice the size of land set aside as protected areas. When these lands are taken into account, the cityscape appears to be greener than indicated by prevailing conservation maps. Focusing on the rapid expansion of golf courses in urban regions, the first major assessment of amphibian and macroinvertebrate fauna confined to golf courses is presented in Paper IV. Threatened species and those more sensitive to eutrophication, tended to be associated with golf ponds relative to ponds of other lands, including nature-protected areas. As to fauna, there was no significant difference between ponds of these different lands.Paper V further investigates culturally maintained areas such as sacred groves and military zones and considers them as under-explored assets for ecosystem and landscape management. They can perform essential complementary ecological functions and may even be instrumental in securing ecosystem services in fragmented landscapes. The social dimension of their sustenance is emphasized and it is argued that such lands and their steward groups should be explicitly incorporated into management through adaptive co-management schemes. Finally, the benefits of planting and managing an introduced alien cacti species (Opuntia spp.) in a highly fragmented landscape are examined by a case study from Madagascar (Paper VI). The cacti provide a range of ecosystem services vital to human subsistence in a location of scarce food and water supplies. Its extensive network of hedges reinforces landscape connectivity, e.g. exchanges between disconnected patches of sacred forest, rich in endemic plant species, and may support endemic wildlife. The thesis demonstrates the need for rethinking current conceptions in ecosystem management. Biotic linkages and the land uses researched may generate biodiversity benefits and ecosystem services rarely recognized in conservation, science or policy. The results imply that identifying and strengthening essential ecosystem processes could reduce the conflict between biodiversity conservation and societal development in urban and other human dominated landscapes. New avenues can be created that contribute to sustainable use of the human life-support systems.
|
|
| 10. |
- Lundberg, Mattias, 1985-
(author)
-
Residual stresses, fatigue and deformation in cast iron
- 2018
-
Doctoral thesis (other academic/artistic)abstract
- The complex geometry of cylinder heads in heavy-duty diesel engines makes grey iron or compact graphite iron a preferred material choice due to its price, castability, thermal conductivity and damping capacity. Today’s strict emission laws have increased the demands on engine performance and engine efficiency. This means that material properties such as fatigue resistance need to be improved. Shot peening is often used to improve the fatigue resistance of components and the benefits of shot peening are associated with the induced compressive surface stresses and surface hardening. How different shot peening parameters can affect fatigue strength of grey and compact graphite iron has been investigated within the project underlying this thesis. To do this, X-ray diffraction (XRD) was utilized for residual stress measurements, scanning electron microscopy (SEM) for microstructural characterizations and mechanical fatigue testing for mechanical quantifications. The ultimate aim of this work has been to increase the fatigue resistance of cast iron by residual stress optimization.XRD measurements and SEM examinations revealed that the shot peening parameters shot size and peening intensity significantly influence residual stresses and surface deformation. Residual stress profiles, similar to the one general considered to improve the fatigue strength in steels, were obtained for both grey and compact graphite iron. Uniaxial push-pull fatigue testing on grey iron with these shot peening parameters reduced the fatigue strength with 15–20 %. The negative effect is likely related to surface damage associated with over peening and relatively high subsurface tensile residual stresses. With very gentle shot peening parameters, the uniaxial fatigue strength were unaltered from the base material but when subjected to bending fatigue an increase in fatigue strength were observed. An alternative way to increase the fatigue strength was to conduct a 30 min annealing heat treatment at 285 XC which increased the fatigue strength by almost 10 % in uniaxial loading. The improvement could be an effect of favourable precipitates forming during the annealing, which could hinder dislocation movement during fatigue.Measuring residual stresses using XRD and the sin2 -method demands accurate X-ray elastic constants (XEC) for meticulous stress analysis. The XEC referred to as 1~2s2 should therefore always be calibrated for the specific material used. The experiments conducted revealed that the XEC value is independent of the testing method used in this work. A small correction from the theoretical value should be applied when the material contains small amounts of residual stresses. The amount of residual stresses has a great impact on the XEC and thus on the stress analysis. Concluding that proper analysis of residual stresses in cast iron is not straight forward.
|
|
