| 1. |
- Dzansi, James
(författare)
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Essays on Financing and Returns on Investment
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This dissertation consists of an introductory chapter and three independent essays on financing investment and their returns. The first essay studies the impact of remittances on domestic investment. The analysis is carried out with a focus on the moderating roles of domestic financial development and institutional quality. The empirical results suggest that remittance inflows are associated with increased domestic investment spending, particularly under conditions of inadequate financial intermediation and poor institutional quality. The second essay evaluates whether remittance inflows into the developing world impedes or spurs manufacturing growth. This study uses manufacturing data on a sample of 40 remittance dependent economies over the period from 1991 to 2004. The results suggest that remittance inflows accelerate manufacturing growth. This evidence is robust to industry- and year-specific effects, a range of country level control variables, and a number of estimators. The final essay examines the monitoring role of large shareholders and returns on investment. Specifically, the paper investigates the relevance of intrinsic motives of the large shareholder to monitor management in order to induce optimal return on investment. The findings suggest that large shareholders are actuated by both intrinsic and extrinsic motives to minimize managerial opportunism and inefficiency.
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| 2. |
- Johansson, Sara, 1975-
(författare)
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Knowledge, Product Differentiation and Trade
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of this thesis is to analyze the influence of knowledge on the export performance of firms in different regions. More specifically, this study focuses on the impact of knowledge on the structure of regional export flows, in terms of horizontal and vertical product differentiation, as well as the geographical distribution of export flows. The thesis consists of four separate papers, which contribute to the overall analysis of knowledge, product differentiation and international trade in different ways. The second chapter presents a study of the effects of regional accessibility to R&D on the diversity of export flows with regard to goods, firms and destination markets. Chapter 3 provides an empirical analysis of vertical product differentiation, i.e. differentiation in terms of product quality, and examines the impact of educated labor and R&D on regional comparative advantages in goods of relatively high product quality. Chapter 4 contains a study of how the regional endowment of highly educated workers affects the structure of export flows, i.e. how the endowment of educated workers impacts on the number of product varieties exported, the average price per variety and the average quantity shipped out. The final chapter presents a micro-level analysis of firms’ propensity to participate in international markets and their propensity to expand export activities by introducing new export products or establishing export links with new destination countries. In summary, the empirical results of this thesis convey the message that regional accessibility to knowledge, embodied in highly educated labor and/or developed through R&D activities, plays a fundamental role in shaping the content and structure of regional export flows. More specifically, the present empirical observations suggest that the regional endowment of knowledge stimulates the size of the export base in terms of exporting firms and number of product varieties. The recurring significance of the accessibility variables in explaining spatial export patterns show that the knowledge endowment of a region must be defined in such ways that it captures sources of potential knowledge spillovers from inside as well as outside its own regional boundaries. This outcome shows that regional variations in knowledge endowments originate both in the actual spatial distribution of a nation’s knowledge labor across regions, and in regional differences in the geographical accessibility to internal and external knowledge labor.
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| 3. |
- Mellander, Charlotta
(författare)
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The Wealth of Urban Regions : On the Location of Creative Individuals and Firms
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This doctoral thesis consists of four individual chapters and an introduction to the thesis. The common feature of the four separate chapters is their focus on the location patterns of creative individuals and firms, the inter-relation between those actors and the regional development and how those actors in the end shape the wealth of urban regions.The first chapter deals with what happens after a new technology is introduced with a focus on the geographical location and distribution. The assumption is that new, non-standardized techniques frequently are initiated and promoted in large urban regions. In order to leave space for new activities, standardized and maturing techniques must gradually be moved to medium and small sized regions.The second chapter analyzes the occupational distribution within Swedish industries, on the basis of characteristics of the individuals they employ. This chapter focuses especially on how to best identify so-called creative industries. It also examines the location patterns of the different types of industries.The third chapter focuses on the role of different types of talent, as well as on factors that shape the distribution of talent across regions. A main theme is the role of universities, tolerance and service diversity. The chapter also examines the economic effect from those factors in combination with talent and technology.The last essay investigates the relationship between tolerance and openness on one hand, and regional housing values on the other. It argues that artists, bohemians and gays affect housing values through two kinds of mechanisms: an aesthetic-amenity premium and a tolerance or open culture premium.
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| 4. |
- Wallin, Tina
(författare)
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Firm renewal in the regional economy
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis consists four independent papers. In each paper the purpose is to analyse firm renewal, with special consideration to regional characteristics. Highlighted here are the knowledge available in the region where a firm is located as well as the local supply of financial intermediaries.The first paper analyses how the interaction of firms’ internal and external knowledge, in terms of knowledge intensive business services (KIBS), is related to the intensive and extensive margins of export flows. The second paper can be considered a continuation of the first, as the focus is solely on the export of new products. Also here, the interaction of internal and external knowledge is the main focus, analysed through education types. The results of these papers suggest that the regional contexts are indeed relevant for firm renewal, as firms that benefit from being located in areas with high external knowledge already have high internal knowledge.The third paper shifts focus to the innovation process itself by analysing how the access to the local supply of banks is related to firms’ perceived obstacles for innovation activities. The results indicate that lower access to banks increases the probability to experience problems obtaining external capital, which could be detrimental for firms’ renewal possibilities in the long run. The fourth paper focus on the creation of firms and analyses whether individuals are more or less likely to be self-employed after having children in a context where an extensive welfare system exists. The results show that individuals are less likely to be self-employed after having children than before, thus lowering the rate of firm renewal in the economy.
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| 5. |
- Warda, Peter
(författare)
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Knowledge, location, and trade
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of this thesis is to analyze how knowledge contained in traded goods influences firms’ demand for labor, and how knowledge-rich routines across space affect the innovative performance in firms and regions.Four research questions are presented that address how knowledge can travel in space. Each research question forms an individual paper in the thesis and can be read separately. The first part of the thesis gives a general introduction and outlines the theoretical background and motivation for the research questions examined in Papers 1 through 4.Papers 1 and 2 address how the knowledge composition of the labor force in Swedish manufacturing firms is impacted by changes in imported goods. Paper 1 analyzes imports of capital and intermediate goods and how their quality influences labor demand in different firm size categories. In Paper 2 the analysis is directed toward an examination of how offshoring of intermediate goods affects different occupations. The technology-specific content of the offshored intermediate goods is emphasized.Moreover, Papers 3 and 4 address how knowledge embodied in exported goods and codified knowledge in patents are affected by changes in new routines. Paper 3 analyzes how firms’ knowledge absorption capacity affects the development, adoption and introduction of new export products among Swedish manufacturing firms. Finally, the focus in Paper 4 is on innovations measured in terms of local patents production in European regions. In this paper, we analyze how the local patents production in a European region benefits both from local R&D inputs in its own region and from spillovers of R&D inputs in other European regions.
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| 6. |
- Wixe, Sofia
(författare)
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Regional diversity and economic performance
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis consists of an introductory chapter and four individual papers. In each paper the relationship between some form of spatial diversity and economic performance is analyzed. Diversity is treated as a potential source of externality effects, mainly in the form of knowledge spillovers.The first paper studies the impact of a broad range of spatial externalities on the productivity of manufacturing plants. While finding positive effects of specialization and competition, there is no support for positive spillovers of either related or unrelated industry diversity. The second paper argues that relatedness should be framed at the level of individuals and consequently should be measured in terms of, for example, education and occupation rather than industry belonging. The results show that educational- and occupational related diversity matter for regional productivity growth, while related industry diversity is positively related to employment growth.The third paper analyzes the importance of neighborhood related diversity, in terms of both industries and education, and internal human capital for firms’ propensity to innovate. The findings support that education and skills are strongly related to firm innovation. Additionally, firms in metropolitan regions are more innovative in neighborhoods with more related diversity in industries, while firms in rural regions seem to benefit more from related diversity in education. In the fourth paper, the location factor of interest is segregation, which may be regarded as inverse diversity. The results show that neighborhood segregation has a negative effect on individual employment. However, it is not the spatial separation of individuals with different backgrounds that causes lower employment but rather the distress of segregated neighborhoods.
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| 7. |
- Arapan, Sergiu, 1973-
(författare)
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Understanding Physical Reality via Virtual Experiments
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis I have studied some problems of condensed matter at high pressures and temperatures by means of numerical simulations based on Density Functional Theory (DFT).The stability of MgCO3 and CaCO3 carbonates at the Earth's mantle conditions may play an important role in the global carbon cycle through the subduction of the oceanic crust. By performing ab initio electronic structure calculations, we observed a new high-pressure phase transition within the Pmcn structure of CaCO3. This transformation is characterized by the change of the sp-hybridization state of carbon atom and indicates a change to a new crystal-chemical regime. By performing ab initio Molecular Dynamics simulations we show the new phase to be stable at 250 GPa and 1000K. Thus, the formation of sp3 hybridized bonds in carbonates can explain the stability of MaCO3 and CaCO3 at pressures corresponding to the Earth's lower mantle conditions. We have also calculated phase transition sequence in CaCO3, SrCO3 and BaCO3, and have found that, despite the fact that these carbonates are isostructural and undergo the same type of aragonite to post-aragonite transition, their phase transformation sequences are different at high pressures.The continuous improvement of the high-pressure technique led to the discovery of new composite structures at high pressures and complex phases of many elements in the periodic table have been determined as composite host-guest incommensurate structures. We propose a procedure to accurately describe the structural parameters of an incommensurate phase using ab initio methods by approximating it with a set of analogous commensurate supercells and exploiting the fact that the total energy of the system is a function of structural parameters. By applying this method to the Sc-II phase, we have determined the incommensurate ratio, lattice parameters and Wyckoff positions of Sc-II in excellent agreement with the available experimental data. Moreover, we predict the occurrence of an incommensurate high-pressure phase in Ca from first-principle calculations within this approach.The implementation of DFT in modern electronic structure calculation methods proved to be very successful in predicting the physical properties of a solid at low temperature. One can rigorously describe the thermodynamics of a crystal via the collective excitation of the ionic lattice, and the ab initio calculations give an accurate phonon spectra in the quasi-harmonic approximation. Recently an elegant method to calculate phonon spectra at finite temperature in a self-consistent way by using first principles methods has been developed. Within the framework of self-consistent ab initio lattice dynamics approach (SCAILD) it is possible to reproduce the observed stable phonon spectra of high-temperature bcc phase of Ti, Zr and Hf with a good accuracy. We show that this method gives also a good description of the thermodynamics of hcp and bcc phases of Ti, Zr and Hf at high temperatures, and we provide a procedure for the correct estimation of the hcp to bcc phase transition temperature.
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| 8. |
- Nyberg, Jan, 1960-
(författare)
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On implant integration in irradiated bone : clinical and experimental studies
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Radiation has an impact on the processes involved in bone- healing, regeneration and remodeling. The mechanisms that cause impaired bone healing of dental implants are not fully understood. Adjunctive treatments to revers radiation effects are limited. Dental implant surgery can be a risk in irradiated jaws and the risk for osteoradionecrosis is of concern. There is no consensus when to install implant after completed radiation therapy or what radiation dosage might cause impaired bone healing. The overall aim of the studies was to investigate bone tissue reactions adjacent to implants after irradiation.I. A clinically long-term follow-up study was performed to assess the outcome of 18 dental implants inserted in five patients with and without irradiated fibula-reconstructed mandibles. Bone tissue reactions adjacent to 14 micro-implants were histologically evaluated. In the clinical follow-up, 15 implants were in function, with an overall success rate of 83%. The histomorphometric analyses demonstrated an impaired osseointegration with reduced bone-to-implant contact (BIC) and bone area (BA), in irradiated sides.II. In an experimental animal study the aim was to find a critical level for a given single external radiation dosages causing impaired implant osseointegration. 9 rats received a single radiation dose of 2, 5, 10, 20 and 30 Gy, respectively to one hind-leg while the other served as a control. Three days post radiation two implants were inserted in each hind-leg and after a period of 5 weeks the implants (n=36) were harvested for histological examination. BIC and BA were lower for irradiated samples for dosages of 20 Gy and higher.III. The aim was to investigate the effects of HBO on osseointegration of titanium implants in irradiated bone. 15 rats received an external single radiation dose of 20 Gy to one hind-leg. 3-days post-irradiation 2 implants were inserted in each hind-leg (n=60). The rats were divided in to 2 groups and one group received hyperbaric oxygen treatment (HBOT) 3 days post-implant insertion (n=8). After 5 weeks the distal implants were harvested for histological examination (n=30) and the proximal implants were used for removal torque tests (n=30). BIC obtained significant higher values for non-irradiated side, independent of HBO or not. BA obtained significant higher values for irradiated sides in the non-HBO group.IV. The aim was to investigate gene expression in irradiate bone after implant insertion for bone formation, resorption and remodelling. 8 rats, received a single radiation dose of 20 Gy to one hind-leg and two implants inserted in each hind-leg 8 weeks after completed radiation therapy. After 5 weeks bone samples with implants were collected for gene expression analysis. ALP, OC (formation) and RANKL/OPG (remodelling) were down regulated in irradiated samples.Conclusion: Bone-anchored dental bridges can be used in selected oro-mandibular reconstructed patients. Bone quality disturbances with impaired osseointegration for dosages of 20 Gy and more were demonstrated in an animal study model. HBO did not enhance osseointegration of implants placed in rat bone during a five-week follow-up period. Irradiation significant reduces bone formation and remodeling under influence of pro-inflammatory and growth factor cytokines
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| 9. |
- Qian, Zhao
(författare)
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Atomistic Modelling of Materials for Clean Energy Applications : hydrogen generation, hydrogen storage, and Li-ion battery
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, a number of clean-energy materials for hydrogen generation, hydrogen storage, and Li-ion battery energy storage applications have been investigated through state-of-the-art density functional theory.As an alternative fuel, hydrogen has been regarded as one of the promising clean energies with the advantage of abundance (generated through water splitting) and pollution-free emission if used in fuel cell systems. However, some key problems such as finding efficient ways to produce and store hydrogen have been hindering the realization of the hydrogen economy. Here from the scientific perspective, various materials including the nanostructures and the bulk hydrides have been examined in terms of their crystal and electronic structures, energetics, and different properties for hydrogen generation or hydrogen storage applications. In the study of chemisorbed graphene-based nanostructures, the N, O-N and N-N decorated ones are designed to work as promising electron mediators in Z-scheme photocatalytic hydrogen production. Graphene nanofibres (especially the helical type) are found to be good catalysts for hydrogen desorption from NaAlH4. The milestone nanomaterial, C60, is found to be able to significantly improve the hydrogen release from the (LiH+NH3) mixture. In addition, the energetics analysis of hydrazine borane and its derivative solid have revealed the underlying reasons for their excellent hydrogen storage properties. As the other technical trend of replacing fossil fuels in electrical vehicles, the Li-ion battery technology for energy storage depends greatly on the development of electrode materials. In this thesis, the pure NiTiH and its various metal-doped hydrides have been studied as Li-ion battery anode materials. The Li-doped NiTiH is found to be the best candidate and the Fe, Mn, or Cr-doped material follows.
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| 10. |
- Alcala, Karine, et al.
(författare)
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The relationship between blood pressure and risk of renal cell carcinoma
- 2022
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Ingår i: International Journal of Epidemiology. - : Oxford University Press (OUP). - 1464-3685 .- 0300-5771. ; 51:4, s. 1317-1327
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The relation between blood pressure and kidney cancer risk is well established but complex and different study designs have reported discrepant findings on the relative importance of diastolic blood pressure (DBP) and systolic blood pressure (SBP). In this study, we sought to describe the temporal relation between diastolic and SBP with renal cell carcinoma (RCC) risk in detail.METHODS: Our study involved two prospective cohorts: the European Prospective Investigation into Cancer and Nutrition study and UK Biobank, including >700 000 participants and 1692 incident RCC cases. Risk analyses were conducted using flexible parametric survival models for DBP and SBP both separately as well as with mutuality adjustment and then adjustment for extended risk factors. We also carried out univariable and multivariable Mendelian randomization (MR) analyses (DBP: ninstruments = 251, SBP: ninstruments = 213) to complement the analyses of measured DBP and SBP.RESULTS: In the univariable analysis, we observed clear positive associations with RCC risk for both diastolic and SBP when measured ≥5 years before diagnosis and suggestive evidence for a stronger risk association in the year leading up to diagnosis. In mutually adjusted analysis, the long-term risk association of DBP remained, with a hazard ratio (HR) per standard deviation increment 10 years before diagnosis (HR10y) of 1.20 (95% CI: 1.10-1.30), whereas the association of SBP was attenuated (HR10y: 1.00, 95% CI: 0.91-1.10). In the complementary multivariable MR analysis, we observed an odds ratio for a 1-SD increment (ORsd) of 1.34 (95% CI: 1.08-1.67) for genetically predicted DBP and 0.70 (95% CI: 0.56-0.88) for genetically predicted SBP.CONCLUSION: The results of this observational and MR study are consistent with an important role of DBP in RCC aetiology. The relation between SBP and RCC risk was less clear but does not appear to be independent of DBP.
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