| 1. |
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| 2. |
- Ali, Syed M. Usman
(författare)
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Fabrication and characterization of ZnO nanostructures for sensing and photonic device applications
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Nanotechnology is an emerging inter-disciplinary paradigm which encompasses diverse fields of science and engineering converge at the nanoscale. This nanoscale science and nanostructure engineering have well demonstrated in the fabrication of sensors/transducers devices with faster response time and better sensitivity then the planer version of the sensor’s configurations. Nanotechnology is not just to grow/fabricate nanostructures by just mixing nanoscale materials together but it requires the ability to understand and to precisely manipulate and control of the developed nanomaterials in a useful way. Nanotechnology is aiding to substantially improve, even revolutionize, many technology and industry sectors like information technology, energy, environmental science, medicine/medical instrumentation, homeland security, food safety, and transportation, among many others. Such applications of nanotechnology are delivering in both expected and unexpected ways on nanotechnology’s promise to benefit the society.The semiconductor ZnO with wide band gap (~ 3.37 eV) is a distinguish and unique material and its nanostructures have attracted great attention among the researchers due to its peculiar properties such as large exciton binding energy (60 meV) at room temperature, the high electron mobility, high thermal conductivity, good transparency and easiness of fabricating it in the different type of nanostructures. Based on all these fascinating properties, ZnO have been chosen as a suitable material for the fabrication of photonic, transducers/sensors, piezoelectric, transparent and spin electronics devices etc. The objective of the current study is to highlight the recent developments in materials and techniques for electrochemical sensing and hetrostructure light emitting diodes (LEDs) luminescence properties based on the different ZnO nanostructures. The sensor devices fabricated and characterized in the work were applied to determine and monitor the real changes of the chemical or biochemical species. We have successfully demonstrated the application of our fabricated devices as primary transducers/sensors for the determination of extracellular glucose and the glucose inside the human fat cells and frog cells using the potentiometric technique. Moreover, the fabricated ZnO based nanosensors have also been applied for the selective determination of uric acid, urea and metal ions successfully. This thesis relates specifically to zinc oxide nanostructure based electrochemical sensors and photonic device (LED) applications.
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| 3. |
- Ali, Zeina M F
(författare)
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Side-chain oxidized oxysterols as metabolic regulators in vivo
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Oxysterols are oxygenated derivatives of cholesterol characterized by a very short half- life and their ability to pass lipophilic membranes easily, and they are considered as important intermediates in the excretion pathways of cholesterol and its conversion to bile acids. Evidence has been presented that the production and flux of oxysterols in the brain may also be of some importance for cognitive functions. The two major oxysterols in the circulation of human and mouse are 24S-hydroxycholesterol (24S- OH) and 27-hydroxycholesterol (27-OH), which are formed by the cytochrome P450 enzymes cholesterol 24-hydroxylase (CYP46A1) and sterol 27-hydroxylase (CYP27A1), respectively. The two oxysterols 27-OH and 24S-OH are both strong inhibitors of cholesterol synthesis and activators of LXR in vitro. However, their role as physiological regulators under in vivo conditions is controversial. The overall aim of this thesis was to investigate the regulatory role of side-chain oxidized oxysterols as metabolic regulators in vivo. In particular, we have studied the role of 24S-OH and 27-OH as regulators of cholesterol synthesis and activators of LXR. We used mouse models with increased levels of 27-OH like human CYP27A1 overexpressor mice (CYP27A1tg) and Cyp7b1 knockout mice (Cyp7b1-/-), as well as a mouse model with no detectable levels of 27-OH in the circulation, Cyp27a1 knockout mice (Cyp 27a1-/-). The latter mice were treated with cholic acid to compensate for the reduced formation of bile acids. Using Cyp27a1-/- mice, we have also studied the possibility that 27-OH mediates the negative effects of dietary cholesterol on memory function in mice. In Paper I, we studied a possible regulatory role of 27-OH and 24S-OH in the brain, using CYP27A1tg mice and Cyp27a1-/- mice. The levels of 27-OH were increased by approximately 12-fold in the brain of CYP27A1tg mice while levels of 24S-OH were decreased by about 25%, most probably due to increased metabolism by the CYP27A1 enzyme. Evidence was presented that cholesterol synthesis was increased in the brain of the two mouse models. There was no upregulation of the LXR-target genes in the brain of either of the two models. The increased synthesis in the brain of the Cyp27a1-/- mice is probably the consequence of the absence of an inhibitory effect of the flux of 27-OH into the brain. The increased cholesterol synthesis in the brain of the CYP27A1tg mice is probably due to the reduced levels of 24S-OH, leading to reduced inhibition of its synthesis. The results of this study are consistent with the possibility that both 24S-OH and 27-OH have a suppressive effect on cholesterol synthesis in the brain. We also conclude that 27-OH is not a general activator of LXR in this tissue. In Paper II, we examined the role of 27-OH in the liver using the three mouse models described above. Only very modest effects on cholesterol synthesis and LXR target genes were observed in the three mouse models. The overall results do not support the contention either that 27-OH is an important regulator of cholesterol homeostasis, or that 27-OH is an activator of LXR-regulated genes under basal conditions in the liver. It has been reported that treatment of mice with dietary cholesterol leads to upregulation of some LXR target genes in the liver. In a study by Chen et al, such upregulation of three different LXR target genes was not seen when treating mice lacking 24S-OH, 25-OH and 27-OH with dietary cholesterol (Chen et al., 2007). It was concluded that a 24-, 25- or 27-hydroxylation step mediated the effect of dietary cholesterol. We show here that similar effects were obtained when treating Cyp27a1-/- mice with dietary cholesterol, suggesting that the effects are mediated by 27-OH. Most of these effects could however not be observed at either the protein level, or at the level of enzyme activity. The results suggest that 27-OH is a mediator of the cholesterol-induced effects on some LXR target genes when the mice are challenged with a high load of dietary cholesterol. The physiological importance of this effect is difficult to evaluate. In Paper III we compared the two mouse models CYP27A1tg and Cyp7b1-/- mice, both of which have high levels of 27-OH in the circulation and the brain. In contrast to CYP27A1tg mice, the levels of 24S-OH in the brain were not decreased in the latter model, and cholesterol synthesis was not affected. This supports the proposal that 24S- OH is of regulatory importance for cholesterol synthesis in the brain. It has been reported that cholesterol synthesis is reduced in the kidney of Cyp7b1-/- mice. Cholesterol synthesis in the kidney of CYP27A1tg mice was not affected, however. We conclude that factors other than high levels of 27-OH are of importance for the reduced cholesterol synthesis in the kidney of the Cyp7b1-/- mice. In Paper IV we tested the possibility that the negative effect of dietary cholesterol on cognition in mice is mediated by 27-OH. The negative effect of dietary cholesterol on spatial memory observed in wild-type mice was not observed in Cyp27a1-/- mice. The latter mice were also treated with cholic acid to compensate for the reduced synthesis of bile acids. Treatment with dietary cholesterol was shown to lead to reduced levels of the “memory protein” Arc (Activity-Regulated Cytoskeleton-associated protein) in the hippocampus of the wildtype mice. This effect was not seen in the hippocampus of Cyp27a1-/- mice. The results are consistent with the possibility that 27-OH is a mediator of the negative effects of dietary cholesterol on cognition. In conclusion, our results suggest that both 24S-OH and 27-OH may be of some regulatory importance for cholesterol synthesis in the brain but not in the liver. Under normal basal conditions 27-OH does not seem to be a general activator of LXR, either in the brain or in the liver. We discuss the possibility that the different effects on cholesterol synthesis in the two organs may be related to the fact that almost all oxysterols in the brain are in the free form, whereas in the liver, most of them are esterified. In addition, we demonstrate that the negative effects of dietary cholesterol on cognition is mediated by 27-hydroxylation.
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| 4. |
- Chabuk, Ali
(författare)
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Solid Waste Landfills in an Arid Environment : Site Selection and Design
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Selecting landfill sites is considered a complicated task because its whole process is based upon several factors and restrictions. This study shows the present status of solid waste management, sources, collection personnel, machinery and equipment that are involved in the waste collection process, financing and financial management for the major cities of the Babylon Governorate in Iraq (Al-Hillah, Al-Qasim, Al-Mahawil, Al-Hashimiyah and Al-Musayiab). The management of waste collection and disposal in the Babylon Governorate and its districts is through open waste dumps, so the quality of the collection and disposal process is poor, and these sites do not conform to the scientific and environmental criteria usually applied in the selection of landfill sites.In the first part of the current study, three methods were used to calculate the solid waste quantity for each specific year up to the year 2030 as well as the cumulative quantity of solid waste for the period (2020-2030) for Babylon Governorate. The results show the cumulative quantity of solid waste resulting from (method 3) receives a high value compared to other methods, and so it is used as a maximum value to estimate the required area for candidate sites for landfills in each district. The generation rate in 2030 will be (0.97, 0.69, 0.48, 0.62 and 0.91) (kg/capita/day) in (Al-Hillah, Al-Qasim, Al-Mahawil, Al-Hashimiyah and Al-Musayiab), respectively, based on method 3, where the estimated annual incremental generation rate is 1 %. The second part of this study aims to find the best sites for landfills in the arid areas that are distinguished by a shallow depth of groundwater. The Babylon Governorate was selected as a case study because it is located in an arid area, and the depths beneath the ground surface to the groundwater level are shallow. For this purpose, 15 important criteria were adopted as follows: groundwater depth, rivers, soil types, agricultural land use, land use, elevation, slope, gas pipelines, oil pipelines, power lines, roads, railways, urban centers, villages and archaeological sites. These criteria were then entered into the geographic information system (GIS). The GIS software has a large capacity to manage and analyze various input data using special analysis tools. In addition, Multi-Criteria Decision Making (MCDM) methods were used to derive the relative weightings for each criterion in different styles. These methods are (Analytical Hierarchy Process (AHP), Simple Additive Weighting (SAW), Ratio Scale Weighting (RSW) and Straight Rank Sum (SRS)).Raster maps of the selected criteria were prepared and analyzed within the GIS software. The final map for candidate landfill sites was obtained through combining the GIS software and (MCDM) methods. Subsequently, comparison methods (Change Detection, Combination, Kappa and Overall Assessment) for each pair of raster maps that result from using the two different methods of multi-criteria decision making were implemented to determine the pixel percentage of matching and non-matching as well as to determine and check the suitability of the selected sites for landfills on both resulting maps using two methods. Two suitable candidate sites for landfills were determined to fulfill the scientific and environmental requirements in each major city. These areas are (6.768 and 8.204) km2 in Al-Hillah, (2.766 and 2.055) km2 in Al-Qasim, (1.288 and 1.374) km2 in Al-Hashimiyah, (2.950 and 2.218) km2 in Al-Mahawil, and (7.965 and 5.952) km2 in Al-Musayiab. The required area of the selected sites can accommodate solid waste from 2020 until 2030 based on the required areas according to the third method.The third part of this study includes soil investigations for the selected landfill sites. The suggested design should ensure that there is no groundwater pollution by leachate from these sites because the groundwater depth is very shallow in the Babylon Governorate. To avoid this problem, soil investigation was conducted at these sites so that the most suitable landfill design could be established. Each site was subjected to field soil tests to find the composition of the soil strata at each site to a depth of 10 m, and these results were compared with the soil properties adopted for final site selection. The Iraqi Ministry of Housing & Construction, National Centre for Construction Laboratories and Research Babylon, Iraq, carried out the analytical work on the soil in 2016. The results of the soil investigation at these sites include the soil profile, groundwater depth, chemical properties, allowable bearing capacity, atterberg limits test results and material characteristics of the soil strata. According to the results of these tests, the best design is the one that puts the compacted waste at the surface.The fourth part of this study covers the selection of a suitable proposed design in the arid areas (Babylon Governorate, Iraq) for the selected landfill siting. In the current study, the design of this landfill includes the suggested soil layers for the liner system and final cover system. For the base liner system (from the bottom toward the top), the composite bottom barrier layer consists of highly compacted sandy clay. The thickness of the bottom barrier layer is 60 cm, and its saturated hydraulic conductivity is 1.0E-7cm/s. The 1.5 mm thick geomembrane (HDPE), with hydraulic conductivity of 2.0E-13 cm/s, is placed over the composite bottom barrier layer. The leachate collection system consists of drainage layer (gravel) with a thickness of 30 cm and a hydraulic conductivity of 3.0E-1 cm/s. The diameter of the main drainpipes is between 15 and 20 cm. The protection layer consists of sand material, and its hydraulic conductivity is 5.0E-3 cm/s. The thickness of the protection layer is 30 cm.The compacted solid waste is placed upon the surface to a height of 2 m because of the shallow groundwater depth and to avoid groundwater contamination by leachate from the landfill site. The density of the compacted waste is 700 kg/m3, and its saturated hydraulic conductivity is 1.0E-5 cm/s.Three scenarios were used for the suggested designs for the final cover system of the landfills in arid areas. The first scenario was “evapotranspiration soil cover (ET) (capillary barriers type)”, the second scenario was a modified cover design of "RCRA Subtitle D", and the third scenario was the “Recommended design”. In this study, “Recommended design”, the third scenario for the final cover system, was adopted in the arid area (Babylon governorate, Iraq) based on combining certain layers from the first and second scenarios. For the three scenarios, the soil components in these designs used was based on available local materials in the study area. The layers of the base liner system were adopted in all scenarios.The third scenario for the final cover system, “Recommended design”, was implemented based on weather parameters in the arid areas. The water infiltrated from the surface of landfill is stored within upper layers that have fine particles. This allows the stored water to evaporate from the soil surface of the landfill or transpire through vegetation due to the high temperature during most months in the study area. The water that enters from the surface of the landfill should be contained above the geomembrane liner and top barrier layer without leakage into the waste body, thereby preventing leachate generation.For the layers of the final cover system (from the bottom to the top), the intermediate cover is used to cover the waste body, and this layer consists of moderate compacted silty clayey loam (native soil). The thickness of the intermediate cover is 30 cm, and its saturated hydraulic conductivity is1.0E-6 cm/s. The foundation layer consists of coarse sand material with a thickness of 30 cm and a saturated hydraulic conductivity of 1.0E-2 cm/s. This layer acts as a cushion for the layers of the final cover system. The gas collection system can be installed within the foundation layer. The top barrier layer is placed over the foundation layer. This layer consists of highly compacted sandy clay of (45 - 60 cm) thickness with compacted lifts (each lift is 15 cm). The saturated hydraulic conductivity of the barrier layer is 1.0E-7 cm/s. The geomembrane liner, (HDPE) of 0.5 cm thickness and a saturated hydraulic conductivity of 2.0E-13 cm/s, is put on top of the barrier layer. The upper layers of the final cover system are the support vegetation layer and the topsoil layer. The composition of the support vegetation layer is moderate compacted loam. This layer is placed directly on the geomembrane liner. The saturated hydraulic conductivity of the support layer is1.0E-5 cm/s, and its thickness is 45 cm. The topsoil layer consists of silty clayey loam, and it is placed over the support vegetation layer with a slope of 3%. The thickness of the topsoil layer is 15 cm, and its hydraulic conductivity is 4.0E-5 cm/s. The Hydrologic Evaluation of a Landfill Performance (HELP 3.95 D) model was applied to the selected landfill sites in the governorate to check if there could be any infiltration of the leachate that will result from the waste in the landfills in the selected sites in the future. The HELP model, which utilizes both weather and soil data, is the most commonly used model for landfill design, and it is employed to evaluate the quantity of water inflow through soil layers for the designed landfill. This suggested landfill is designed using the weather parameters (rainfall, temperature, solar, and the required date to calculate evapotranspiration) for the 12 consecutive years from 2005 to 2016, as well the required data for soil design.In the HELP model, the result for the suggested landfill design for both the recommended design (third scenario) and the second scenario was a modified cover design of "RCRA Subtitle D", which showed there was no leachate through the soil
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| 5. |
- Gyger, Samuel, 1991-
(författare)
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Integrated Photonics for Quantum Optics
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Quantum physics allows us a vision of Nature's forces that bind the world, all its seeds and sources. After decades of primarily scientific research, we've arrived at a stage in time where quantum technology can be applied to practical problems and add value outside the field. Four pillars of quantum technologies are commonly identified: quantum computing, quantum simulation, quantum communication, and quantum sensing. For example, quantum computers will allow us to model quantum systems beyond our current capabilities, and quantum communication allows us to protect information unconditionally based on physics. Quantum sensing will enable us to measure our reality beyond classical limits.Within all of these areas, optical photons play a unique role. In quantum computer implementations (e.g. photonic, trapped ion, or superconducting) photons can serve as a computational resource, for system read-out, or for linking distant hardware nodes. Quantum communication can only be realized via photons, utilizing the low-loss propagation of photons in optical fibers, on photonic devices as well as in free space. In quantum sensing and metrology, squeezed light can be used to go beyond the current limits of sensing methods. Therefore, the quantum technology field crucially relies on precise and efficient methods to generate, steer, manipulate and detect photons.This dissertation discusses work in integrated photonic circuits, self-assembled semiconductor quantum dot devices, and superconducting nanowire single--photon detectors.We integrate multiple materials on a silicon nitride platform, including Cu2O as a platform for solid-state Rydberg physics, WS2 to improve non-linear light-generation within Si3N4, and hBN as an excellent single-photon emitter.We demonstrate optically active quantum dots as single-photon emitters in the telecom C-band and their compatibility with commercial telecom equipment.We strain-control the fine-structure splitting of these devices, which is required for future quantum interference-based protocols.Finally, we study superconducting nanowire single-photon detectors (SNSPD) and combine them with photonic micro-electromechanical systems (MEMS), establishing a cryo-compatible, reconfigurable photonic platform.
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| 6. |
- Harandi, Ali M, 1968
(författare)
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Innate and adaptive immunity in genital HSV-2 infection: Implications for vaccine development
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Herpes simplex virus type 2 (HSV-2) is a sexually transmitted pathogen that infects the genital tract mucosa and is the most common case of genital ulcers in humans. Despite numerous studies, little is known about the mechanisms involved in immune protection and no anti-herpes vaccine has been developed to date. Thus, a better understanding of the immune mechanisms deployed against HSV-2 could facilitate the development of an effective vaccine against human genital herpes infection. The aims of the present thesis were to elucidate the roles of different immunological components in both innate and acquired immunity against genital HSV-2 infection. In addition the ability of HSV-2-pulsed dendritic cell vaccination to induce protective immunity in mice, was assessed. A well-established mouse model of genital HSV-2 infection was employed. In this model, vaginal inoculation of mice with HSV-2 provokes a severe genital infection leading to a lethal neurological illness, whereas primary genital infection/vaccination with the attenuated strain HSV-2 (TK-) gives rise to the development of protective immunity against later infection by wild type HSV-2. Using this model, it was shown in gene-targeted mice that B cells secreting natural antibodies, IFN-g, IL-12 and IL-18 are implicated in the innate control of primary genital infection, whereas CD4+ T cells and IFN-g are crucial for the development of acquired protective immunity against challenge one month later. The protective immunity in vaccinated mice was shown to be associated with HSV-2-specific IFN-g responses in vitro and delayed type hypersensitivity responses in vivo. However, CD8+ T cells, B-cells, IL-12 and IL-18 can be circumvented during the development of adaptive immune protection. Protective immunity appeared to be associated with a rapid induction of IFN-g-dependent RANTES production in the vaginal mucosa following a vaginal HSV-2 challenge. Finally, it was demonstrated that intravenous or subcutaneous vaccination of mice with HSV-2-antigen-pulsed bone marrow-derived dendritic cells confers protective immunity against genital herpes infection. These data have implications for our understanding of the immune mechanisms involved in protective immunity against HSV-2 infection and may facilitate development of an effective vaccine against genital herpes infections.
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| 7. |
- Hedström, Axel, 1989-
(författare)
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Empirical Studies on Economic and Financial Spillovers : Asymmetric Risk and Dependence Modeling
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Financial assets are volatile, and volatility becomes more intense in terms of size and rate of recurrence when markets are uncertain and growing rapidly. The fact that the recurrence rate increased during crisis periods, such as the IT bubble in the early 2000 and the global financial crisis that started in 2007, is a key finding in the literature. Estimating these results requires modeling a time series that can consider volatility clustering. However, the prominent model in finance and economics estimates that the average volatility increases when uncertainty increases. This modeling process needs to consider the asymmetry that financial assets and economic outcomes, such as gross domestic product (GDP) exhibit, which tend to fall drastically in a short period and increase steadily over a long period. To model these different behaviors, one must consider the asymmetric nature of the return, for example, when a stock has extremely low or extremely high returns in a day. To model this behavior, I used several methods in settings that could better explain what happens during market periods when there is higher uncertainty. The general finding is that correlations are higher when returns are in the lower quantiles, called the left tails. Thus, financial assets are positively correlated, especially during periods of increased uncertainty. It is not only clustering that one would try to explain, but another issue is the prediction of one asset’s effect on another. The effect of one asset on another asset is called the spillover effect. We tried to distinguish between events that happen during the same time that affect all assets. These events are called systematic risk, and the effects that one asset has on another asset is called systemic risk. Explaining the systemic risk typically has higher priority from a policy perspective, as systemic risk can be a driver for risk transmission from one asset to another, creating a chain of risk or a spiral of risk. Hence, the approaches I used can model that chain of risk and predict risk transmission while controlling for external factors that increase uncertainty. The results of this research show the connection between energy assets and renewable energy stocks in Papers 1 and 2. For instance, we found that there is a possibility of adjusting the European carbon emission cap and that renewable energy stocks positively correlate with energy commodities in the tails. Thus, renewable energy stocks follow a macroeconomic cycle. The findings of Paper 3 show the systemic and systematic nature of cross-country spillovers between emerging and developed financial markets, and that the spillover is time-varying with increasing spillovers in crisis periods. Paper 4 examines the Nordic banking sector. The results show that banks’ spillover to their local markets is due to their systemic importance and the strength of the spillover is related to the bank’s characteristics. In the final Paper, I studied the upside and downside movement asymmetry of stocks and found that betting on upside volatility is better than a portfolio perspective but comes at the cost of increased pricing errors. The empirical findings of this thesis significantly contribute to policymakers and institutional investors in portfolio diversification and risk management.
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| 8. |
- Lind, Thérèse, 1989-
(författare)
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Financial literacy, motivated reasoning, and gender : essays in behavioral economics
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- I wrote this thesis to create a better understanding of how individual characteristics influence our feelings, our behavior and our way of interpreting information. My focus is on financial behavior and financial information, however I also consider a political context. I investigate the (usually) enabling abilities of financial literacy and numeracy. I also consider impediments such as stereotype threat and motivated reasoning, which can prevent people from engaging in certain behaviors or from interpreting information objectively. Both processes stem from valued beliefs and psychological foundations, consequently peoples’ efforts, decisions, and evaluations are based on them.The first essay, “Competence, confidence, and gender: The role of perceived and actual financial literacy in household finance,” broadens our understanding of the benefits of financial competence. I contrast perceived and actual levels of financial literacy, and consider the role of numeracy and cognitive reflective ability. I conclude that perceived and actual levels of financial literacy positively affect behavior and wellbeing; however, perceived financial literacy more so than actual financial literacy. No such effect is observed for numeric ability and cognitive reflection. Furthermore, women are more anxious about financial matters even though they tend to engage more frequently in the considered financial behaviors.The second essay, “Threatening finance? Examining the gender gap in financial literacy,” continues my exploration of the relationship between gender and financial literacy. In a series of studies, I investigate whether the observed gender gap in financial literacy can be identified in nonnumerical contexts, if it can be associated with confidence in financial matters, and if it can be attributed to stereotype threat, which posits that inbuilt prejudices about gender and finance undermine women’s performance of tasks that involve finance. The results show that the observed gender gap in financial literacy is robust even in nonnumerical financial contexts and suggest that a stereotype threat for women in the financial domain might be present. The gender gap in financial literacy could not be attributed to a difference in (displayed) confidence.In the third essay, “Preferences for lump-sum over divided payment structures,” I investigate whether or not people display systematic preferences for lump–sum or divided payment structures and how these preferences differ in gain (benefit) and loss (payment) situations. I investigate what happens when payments belong to a single underlying event, such as when people can choose to pay immediately or in installments. I also examine whether or not individual differences in time preferences, risk preferences, numeracy, and financial literacy are associated with preferences for one payment structure or the other. The aggregate results show a tendency for people to prefer obtaining and paying money in lump sums. I find no systematic indication that the considered individual differences play a role in this type of decision.The fourth essay, “Motivated reasoning when assessing the effect of refugee intake,” inquires into differences in worldview ideology, whether people identify as nationally or globally oriented, hinder them from objectively interpreting information. I use an experiment to find out if people display motivated reasoning when interpreting numerical information about the effects of refugees on the crime rate. Our results show evidence of motivated reasoning along the lines of worldview ideology. However, individuals with higher numeric ability were less likely to engage in motivated reasoning, leading to the conclusion that motivated reasoning is more likely to be driven by feelings and emotional cues than by deliberate analytical processes.
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| 9. |
- Lång, Elisabeth, 1983-
(författare)
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Short- and Long-Term Influences of Education, Health Indicators, and Crime on Labor Market Outcomes : Five Essays in Empirical Labor Economics
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The objective of this thesis is to improve the understanding of how several individual characteristics, namely education (years of schooling), health indicators (height, weight, smoking, alcohol consumption, and exercise), criminal behavior, and crime victimization, influence labor market outcomes in the short and long run. The first part of the thesis consists of three studies in which I adopt a within-twin-pair difference approach to analyze how education, health indicators, and earnings are associated with each other over the life cycle. The second part of the thesis includes two studies in which I use field experiments in order to test the employability of exoffenders and crime victims.The first essay, Learning for life?, describes an analysis of the education premium in earnings and health-related behaviors throughout adulthood among twins. The results show that the education premium in earnings, net of genetic inheritance, is rather small over the life cycle but increases with the level of education. The results also show that the education premium in health-related behaviors is mainly concentrated on smoking habits. The influences of education on earnings and health-related behaviors seem to work independently of each other, and there are no signs that health-related behaviors influence the education premium in earnings or vice versa.The second essay, Blowing up money?, details an analysis of the association between smoking and earnings in two different historical social contexts in Sweden: the 1970s and the 2000s. I also consider possible differences in this association in the short and long run as well as between the sexes. The results show that the earnings penalty for smoking is much stronger in the 2000s as compared to the 1970s (for both sexes) and that it is larger in the long run as compared to the short run (for men).The third essay, Two by two, inch by inch, describes an analysis of the height premium among Swedish twins. The results show that the height premium is relatively constant over the life cycle and that it is larger below median height for men and above median height for young women. The estimates are similar for monozygotic and dizygotic twins, indicating that environmentally and genetically induced height differences are similarly associated with earnings over the life cycle.The fourth essay, The employability of ex-offenders, published in IZA Journal of Labor Policy (2017), 6:6, details an analysis of whether male and female exoffenders are discriminated against when applying for jobs in the Swedish labor market. The results show that employers do discriminate against exoffenders but that the degree of discrimination varies across occupations. Discrimination against ex-offenders is pronounced in female-dominated and high-skilled occupations. The magnitude of discrimination against exoffenders does not vary by applicants’ sex.The fifth essay, Victimized twice?, describes an analysis of whether male and female crime victims are discriminated against when applying for jobs in the Swedish labor market. This study is the first to consider potential hiring discrimination against crime victims. The results show that employers do discriminate against crime victims. The discrimination varies with the sex of the crime victim and occupational characteristics and is concentrated among high-skilled jobs for female crime victims and among femaledominated jobs for male crime victims.
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| 10. |
- Naderi, Ali, 1974-
(författare)
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Polyelectrolytes : Bottle-Brush Architectures and Association with Surfactants
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis has the dual purpose of raising awareness of the importance of the mixing protocol on the end products of polyelectrolyte-oppositely charged surfactant systems, and to contribute to a better understanding of the properties of bottle-brush polyelectrolytes when adsorbed onto interfaces. In the first part of this thesis work, the effects of the mixing protocol and the mixing procedure on formed polyelectrolyte-oppositely charged surfactant aggregates were investigated. It was shown that the initial properties of the aggregates were highly dependent on the mixing parameters, and that the difference between the resulting aggregates persisted for long periods of time. The second part of the studies was devoted to the surface properties of a series of bottle-brush polyelectrolytes made of charged segments and segments bearing poly(ethylene oxide) side chains; particular attention was paid to the effect of side chain to charge density ratio of the polyelectrolytes. It was shown that the adsorbed mass of the polyelectrolytes, and the corresponding number of poly(ethylene oxide) bearing segments at the interface, went through a maximum as the charge density of the polyelectrolyte was increased. Also, it was found that bottle-brush polyelectrolyte layers were desorbed quite easily when subjected to salt solutions. This observation was rationalized by the unfavourable excluded volume interactions between the side chains and the entropic penalty of confining them at an interface, which weaken the strength of the binding of the polyelectrolytes to the interface. However, it was shown that the same side chains effectively protect the adsorbed layer against desorption when the layer is exposed to solutions containing an oppositely charged surfactant. Investigation of the lubrication properties of the bottle-brush polyelectrolytes in an asymmetric (mica-silica) system also related the observed favourable frictional properties to the protective nature of the side chains. The decisive factor for achieving very low coefficients of friction was found to be the concentration of the side chains in the gap between the surfaces. Interestingly, it was shown that a brush-like conformation of the bottle-brush polyelectrolyte at the interface has little effect on achieving favourable lubrication properties. However, a brush-like conformation is vital for the resilience of the adsorbed layer against the competitive adsorption of species with a higher surface affinity.
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