Ectomycorrhizal fungi are able to ameliorate heavy metal stress to host trees in polluted soils. Their sensitivity or tolerance to heavy metals is usually examined based on growth and proliferation on heavy metal amended media. However, there are no data on cellular effects of heavy metals and detoxification in live cells of these fungi. Organelle morphology has recently been recognized as an indication of cellular health and its changes can be used to assess cytotoxicity. The aim of this study was, therefore, to investigate short term effects of common heavy metal pollutants, Zn2+ and Ni2+ on the morphology of vacuoles, mitochondria and microtubules in hyphal tip cells of two Paxillus involutus strains. Vacuoles, mitochondria and microtubules were labeled with Oregon Green?? 488 carboxylic acid diacetate, 3,3'-dihexyloxacarbocyanine iodide ((DiOC6(3)) and anti-??- tubulin antibodies, respectively. They were treated with 0-1 mmol L-1 NiSO4 or 0-100 mmol L-1 ZnSO4 or K2SO4 (SO4 2- control) and examined by fluorescence microscopy. Vacuoles and mitochondria in untreated hyphal tip cells of strain P2 which originated from a heavy metal-rich soil were motile and tubular forming networks. Exposure to the metals caused tubular vacuole thickening and vesiculation as well as fragmentation of tubular mitochondria in living hyphal tip cells. The highest K2SO4 concentration also had severe effects on mitochondria. These effects were metal, concentration and exposure time dependent. NiSO4 caused these effects at a hundred fold lower concentration than ZnSO4 and induced severe microtubule disruption. Vacuole tubularity recovered after removal of the metal solutions depending on the metal, concentration and exposure time. Mitochondrial tubularity recovered to pretreatment morphology in a shorter time and even during exposure to the highest metal concentration. Vacuoles of strain P46 which originated from a non-polluted soil were pleomorphic, but mainly spherical with occasional tubular interconnections. The vacuoles were too sensitive to UV light exposure required for fluorescence microscopy to investigate their response to heavy metals. The mitochondrial network and microtubules resembled those of strain P2. The highest ZnSO4 and NiSO4 concentrations caused similar trends in response of mitochondria and microtubules of the two strains. However, mitochondria of strain P46 were less sensitive at lower metal concentrations. The highest K2SO4 concentration had more severe effects on mitochondria of strain P46 than in strain P2 from which tubularity was not recovered. This investigation is the first to reveal that heavy metals affect organelle morphology in two strains of an ectomycorrhizal fungus. Nickel effects on the organelles are likely to result from microtubule disruption. Metal induced mitochondrial fragmentation is possibly an apoptotic response and the recovery of tubular organelle networks suggests cellular detoxification.

Advances in our understanding of osteoarthritis (OA) have made development of sensitive measurement tools a priority. The literature review in this thesis found that one of the measurement tools, arthroscopy, had not been fully evaluated. This body of work evaluated the performance of arthroscopic assessments of articular cartilage (AC) in early OA with specific reference to the OMERACT filter. Preliminary studies in plastic knee arthroscopy simulation models found that estimates of AC lesion area had poor accuracy and reliability. Measurements of lesion diameter were greatly improved by the use of specially designed measurement probes but these did not prove feasible in vivo. Ovine studies evaluated discriminant and criterion validity. Biomechanical assessments served as the gold standard for AC stiffness while macroscopic, thickness and histologic assessments were used for gross structural damage. An hybrid gold standard assessment was devised to validate arthroscopic estimates of Severity and Extent of chondropathy. Arthroscopic global assessments discriminated between normal and very early OA but discrimination between different states of OA was less impressive. Assessments of the Severity of chondropathy had acceptable accuracy and moderate reliability. While arthroscopy could not examine the entire articular surface and estimates of Extent of chondropathy were subject to very large error they broadly resembled those of the hybrid gold standard assessment and they enhanced composite score performance. Composite score validity was further improved by inclusion of estimates of chondro-osteophyte. An empirical approach to composite algorithm weighting to optimise discriminant validity was developed. This approach compared favourably with previously described methods. Composite scores proved best at discriminating between normal and very early OA but were also capable of detecting small changes in OA. Arthroscopic asessments of AC damage meet the OMERACT filter criteria of Truth and Discrimination. Assessments using current arthroscopic technology should include estimates of the Extent of all grades of chondropathy. The optimal scoring algorithm should be determined empirically. Arthroscopic assessments using existing technology may be used to validate noninvasive assessments of the Severity chondropathy but not of Extent. Future efforts to improve arthroscopic assessments of AC should focus on reducing random error associated with estimates of extent.

Ectomycorrhizal fungi are able to ameliorate heavy metal stress to host trees in polluted soils. Their sensitivity or tolerance to heavy metals is usually examined based on growth and proliferation on heavy metal amended media. However, there are no data on cellular effects of heavy metals and detoxification in live cells of these fungi. Organelle morphology has recently been recognized as an indication of cellular health and its changes can be used to assess cytotoxicity. The aim of this study was, therefore, to investigate short term effects of common heavy metal pollutants, Zn2+ and Ni2+ on the morphology of vacuoles, mitochondria and microtubules in hyphal tip cells of two Paxillus involutus strains. Vacuoles, mitochondria and microtubules were labeled with Oregon Green?? 488 carboxylic acid diacetate, 3,3'-dihexyloxacarbocyanine iodide ((DiOC6(3)) and anti-??- tubulin antibodies, respectively. They were treated with 0-1 mmol L-1 NiSO4 or 0-100 mmol L-1 ZnSO4 or K2SO4 (SO4 2- control) and examined by fluorescence microscopy. Vacuoles and mitochondria in untreated hyphal tip cells of strain P2 which originated from a heavy metal-rich soil were motile and tubular forming networks. Exposure to the metals caused tubular vacuole thickening and vesiculation as well as fragmentation of tubular mitochondria in living hyphal tip cells. The highest K2SO4 concentration also had severe effects on mitochondria. These effects were metal, concentration and exposure time dependent. NiSO4 caused these effects at a hundred fold lower concentration than ZnSO4 and induced severe microtubule disruption. Vacuole tubularity recovered after removal of the metal solutions depending on the metal, concentration and exposure time. Mitochondrial tubularity recovered to pretreatment morphology in a shorter time and even during exposure to the highest metal concentration. Vacuoles of strain P46 which originated from a non-polluted soil were pleomorphic, but mainly spherical with occasional tubular interconnections. The vacuoles were too sensitive to UV light exposure required for fluorescence microscopy to investigate their response to heavy metals. The mitochondrial network and microtubules resembled those of strain P2. The highest ZnSO4 and NiSO4 concentrations caused similar trends in response of mitochondria and microtubules of the two strains. However, mitochondria of strain P46 were less sensitive at lower metal concentrations. The highest K2SO4 concentration had more severe effects on mitochondria of strain P46 than in strain P2 from which tubularity was not recovered. This investigation is the first to reveal that heavy metals affect organelle morphology in two strains of an ectomycorrhizal fungus. Nickel effects on the organelles are likely to result from microtubule disruption. Metal induced mitochondrial fragmentation is possibly an apoptotic response and the recovery of tubular organelle networks suggests cellular detoxification.

Advances in our understanding of osteoarthritis (OA) have made development of sensitive measurement tools a priority. The literature review in this thesis found that one of the measurement tools, arthroscopy, had not been fully evaluated. This body of work evaluated the performance of arthroscopic assessments of articular cartilage (AC) in early OA with specific reference to the OMERACT filter. Preliminary studies in plastic knee arthroscopy simulation models found that estimates of AC lesion area had poor accuracy and reliability. Measurements of lesion diameter were greatly improved by the use of specially designed measurement probes but these did not prove feasible in vivo. Ovine studies evaluated discriminant and criterion validity. Biomechanical assessments served as the gold standard for AC stiffness while macroscopic, thickness and histologic assessments were used for gross structural damage. An hybrid gold standard assessment was devised to validate arthroscopic estimates of Severity and Extent of chondropathy. Arthroscopic global assessments discriminated between normal and very early OA but discrimination between different states of OA was less impressive. Assessments of the Severity of chondropathy had acceptable accuracy and moderate reliability. While arthroscopy could not examine the entire articular surface and estimates of Extent of chondropathy were subject to very large error they broadly resembled those of the hybrid gold standard assessment and they enhanced composite score performance. Composite score validity was further improved by inclusion of estimates of chondro-osteophyte. An empirical approach to composite algorithm weighting to optimise discriminant validity was developed. This approach compared favourably with previously described methods. Composite scores proved best at discriminating between normal and very early OA but were also capable of detecting small changes in OA. Arthroscopic asessments of AC damage meet the OMERACT filter criteria of Truth and Discrimination. Assessments using current arthroscopic technology should include estimates of the Extent of all grades of chondropathy. The optimal scoring algorithm should be determined empirically. Arthroscopic assessments using existing technology may be used to validate noninvasive assessments of the Severity chondropathy but not of Extent. Future efforts to improve arthroscopic assessments of AC should focus on reducing random error associated with estimates of extent.

Neuromelanin (NM) is a dark polymer pigment present in specific populations of catecholaminergic neurons in the brain. Interest in this pigment has rekindled in recent years because of a hypothesised link between NM and the especial vulnerability of NM-containing neurons to cell death in Parkinson???s disease (PD). Many aspects of the biology of NM are yet to be characterised. It is not known if NM like the similar melanin of the skin is synthesised via an enzymatic pathway or solely through autoxidation as has traditionally been thought. Examination of the ultrastructure of NM granules showed that in contrast to peripheral melanosomes, an electron-lucent lipid component was present that represented 30% of pigment volume. The identity of the lipid component of NM has remained unclear since it was first suggested that NM contained lipid in the 1960???s. NM lipid was biochemically isolated from the substantia nigra of 32 human brains. Using reversed-phase high performance liquid chromatography, atmospheric pressure chemical ionisation mass spectrometry and 1H- and 13C NMR techniques, it was shown for the first time that the NM lipid is the polyisoprenoid dolichol. The age-related development and regulation of NM has not previously been described. Optical density and area measurements of unstained NM in ventral substantia nigra neurons spanning the ages of 24 weeks to 95 years old demonstrated three developmental phases. NM was not present at birth and initiation of pigmentation began at approximately 3 years of age, followed by a period of increasing pigment granule number and colouration until age 20. In PD brain, the ultrastructure of NM demonstrated that the amount of lipid did not change. However, filipin staining showed a reduction of cholesterol in PD NM containing neurons. In addition, immunogold staining of ??-synuclein demonstrated that this protein redistributed to the NM lipid in PD brain. The finding of phases in the development of NM, and the identification of lipid species in NM suggest that NM biology is regulated. This thesis has also demonstrated changes in the lipid and associated proteins in PD, suggesting NM???s chemical composition alters which may have functional consequences that contribute to PD.

Neuromelanin (NM) is a dark polymer pigment present in specific populations of catecholaminergic neurons in the brain. Interest in this pigment has rekindled in recent years because of a hypothesised link between NM and the especial vulnerability of NM-containing neurons to cell death in Parkinson???s disease (PD). Many aspects of the biology of NM are yet to be characterised. It is not known if NM like the similar melanin of the skin is synthesised via an enzymatic pathway or solely through autoxidation as has traditionally been thought. Examination of the ultrastructure of NM granules showed that in contrast to peripheral melanosomes, an electron-lucent lipid component was present that represented 30% of pigment volume. The identity of the lipid component of NM has remained unclear since it was first suggested that NM contained lipid in the 1960???s. NM lipid was biochemically isolated from the substantia nigra of 32 human brains. Using reversed-phase high performance liquid chromatography, atmospheric pressure chemical ionisation mass spectrometry and 1H- and 13C NMR techniques, it was shown for the first time that the NM lipid is the polyisoprenoid dolichol. The age-related development and regulation of NM has not previously been described. Optical density and area measurements of unstained NM in ventral substantia nigra neurons spanning the ages of 24 weeks to 95 years old demonstrated three developmental phases. NM was not present at birth and initiation of pigmentation began at approximately 3 years of age, followed by a period of increasing pigment granule number and colouration until age 20. In PD brain, the ultrastructure of NM demonstrated that the amount of lipid did not change. However, filipin staining showed a reduction of cholesterol in PD NM containing neurons. In addition, immunogold staining of ??-synuclein demonstrated that this protein redistributed to the NM lipid in PD brain. The finding of phases in the development of NM, and the identification of lipid species in NM suggest that NM biology is regulated. This thesis has also demonstrated changes in the lipid and associated proteins in PD, suggesting NM???s chemical composition alters which may have functional consequences that contribute to PD.

This thesis investigates the impact of insider trading regulation and its enforcement on bid-ask spreads, information asymmetry proxies, volatility, trade frequency and trade sizes. It employs an exclusive intra-day market-microstructure data-set for 29 countries and 32 exchanges and utilizes structural simultaneous equations models with distributed geometric lags estimated with GMM, controlling for market architecture, trading demand, minimum tick size and Fama-French factors. This thesis finds that enforcement of insider trading regulation in a country, rather than the strictness of written insider trading law, reduces information asymmetry and bid-ask spreads, increases volatility, and has an overall positive impact on traded value. The positive impact is mostly concentrated in the smallest stocks in the sample. The regulation of disclosure requirements has similar, but not identical, beneficial externalities in the market. The results support the prediction by Bhattacharya and Daouk (2002) that the fall in the cost of equity that results from insider trading prosecution in a country is due to a reduction in adverse selection. This thesis also find some support of the free inside information scenario of Medrano and Vives (2004), where volatility increases when insiders are forced to disclose the inside information before legally trading on it, if insider trading is not permitted and the regulation is enforced.

The United States enjoys a per-capita gross domestic product more than five times the size of Mexico (World Bank, 2015). Yet the immigration policies of the United States fail to recognize the incentives workers in Mexico have to immigrate, legally or otherwise, into the United States. The law alone fails to control the movement of people across a 1,900-mile land border. Immigration has contributed to the economic and cultural dynamism of the United States. In the short-run, it may create economic winners and losers, leading to domestic tension. After Congress debated and then rejected President George W. Bush’s immigration overhaul in 2007, state governments started adopting laws and rules targeting illegal immigrants. Many of those laws forced employers to use the electronic E-Verify system to check whether prospective hires were eligible to work in the United States. Typically, the primary goal was to bar illegal immigrants from the workforce. Additional goals included boosting the employment prospects and earnings of legal residents, and encouraging illegal immigrants to voluntarily leave markets governed by E-Verify requirements. Politicians focused particular attention on the U.S. agricultural industry, which is not surprising since U.S. Department of Agriculture surveys show roughly half the agricultural workforce is working in the country illegally. Farmers say they hire illegal workers because they cannot find enough U.S. workers to harvest labor-intensive produce and livestock. Supporters of the E-Verify law in Georgia said one of their policy goals was to encourage farmers to secure legal, foreign laborers through the federally run H2A visa program. The H2A system allows growers facing domestic labor shortages to import foreign laborers for up to 10 months, though the program is bureaucratically cumbersome and requires that cost-sensitive growers pay above-market wages. To determine whether E-Verify laws encourage H2A use, the author reviewed every state E-Verify law affecting the agricultural industry. After aggregating H2A usage data at the state level, the author conducted a fixed-effects regression that controls for years, monthly seasonal fluctuations, state effects, H2A wage costs, and the relative strength of a state’s E-Verify law. While there is anecdotal evidence that E-Verify laws may disrupt labor markets, there is little statistical evidence that state E-Verify laws cause farmers to increasingly rely on the H2A system. Surprisingly, there is statistical evidence that the strictest E-Verify laws may reduce H2A usage.

During sea rescue operations it is common for the rescue vessels to operate in water with high number of debris that can get stuck in the propulsor. In particular plastic ropes that can get tangled around the shaft and melt causing a complete stop or damage the motor. Currently rim driven shaft-less thrusters have proven to deal with debris in a better way than conventional motors, but they usually operate only at low speeds. The Swedish Sea Rescue Society along with Rolls-Royce and other partners such as Marna decided to start developing a motor combining the idea of the rim driven thrusters driven by a Permanent magnet motor and a water jet to increase the thrust. In this thesis a conceptual design for this motor is presented, in which bearings and seals have been chosen from standard components as well as the bolts and other components, and all the housing has been designed. In order to design the housing and choose the standard components, three main factors were taken into account: not using extra systems, modularity and being as compact as possible. By focusing on those three requirements different bearing and seals solutions were studied and analyzed to check their viability. Furthermore, in order to verify the design and components chosen, mathematical models through MATLAB and simulations with ANSYS were carried out. Finally the drawings of the non standard components were added including the tolerances defined by the standard components. / Under räddningsuppdrag är det vanligt att räddningsbåtar opererar i vatten med mycket skräp som kan sugas in i propulsorn. Speciellt plastrep kan trassla in sig runt axeln och smälta och orsaka driftstopp eller skada motorn. För närvarande finns periferi-drivna, axellösa propulsorer som har visat sig hantera skräp på ett bättre sätt än konventionella, men de är vanligen bara designade för låga farter. Sjöräddningssällskapet beslutade sig därför tillsammans med Rolls-Royce och andra partners som Marna att börja utveckla en motor som kombinerar en periferidriven propulsor med en vattenjet I detta arbete presenteras en konceptuell design för denna motor, där lager och tätningar såväl som bultar och andra komponenter har valts från standardkomponenter. För att utforma höljet och välja standardkomponenterna beaktades tre huvudfaktorer: att undvika extra system, modularitet och att vara så kompakt som möjligt. Genom att fokusera på dessa tre krav studerades och analyserades olika lager- och tätningslösningar. För att kontollera designen och komponenterna som valts genomfördes dessutom matematiska analyser med hjälp av Matlab och simuleringar med ANSYS. Slutligen togs ritningar av icke-standardkomponenter fram, inklusive toleranser definierade av standardkomponenterna.

Verification, as opposed to Testing and Post-Silicon Validation, is a critical step for Integrated Circuits (IC) Design, answering the question "Are we designing the right function?" before the chips are manufactured. One of the core areas of Verification is Equivalence Checking (EC), which is a special yet independent case of Model Checking (MC). Equivalence Checking aims to prove that two circuits, when fed with the same inputs, produce the exact same outputs. There are broadly two ways to conduct Equivalence Checking, simulation and Formal Equivalence Checking. Simulation requires one to try out different input combinations and observe if the two circuits produce the same output. Obviously, since it is not possible to enumerate all combinations of different inputs, completeness cannot be guaranteed. On the other hand, Formal Equivalence Checking can achieve 100% confidence. As the number of gates and in particular, the number of flip-flops, in circuits has grown tremendously during the recent years, the problem of Formal Equivalence Checking has become much harder â A recent evaluation of a general-case Formal Equivalence Checking engine [1] shows that about 15% of industrial designs cannot be verified after a typical sequential synthesis flow. As a result, a lot of attention on Formal Equivalence Checking has been drawn both academically and industrially. For years Combinational Equivalence Checking(CEC) has been the pervasive framework for Formal Equivalence Checking(FEC) in the industry. However, due to the limitation of being able to verify circuits only with 1:1 flip-flop pairing, a pure CEC-based methodology requires a full regression of the verification process, meaning that performing sequential optimizations like retiming or FSM re-encoding becomes somewhat of a bottleneck in the design cycle [2]. Therefore, a more powerful framework — Sequential Equivalence Checking (SEC) — has been gradually adopted in industry. In this thesis, we target on Sequential Equivalence Checking by finding efficient yet powerful group of relationships (invariants) among the signals of the two circuits being compared. In order to achieve a high success rate on some of the extremely hard-to-verify circuits, we are interested in both two-node and multi-node (up to 4 nodes) invariants. Also we are interested in invariants among both flip-flops and internal signals. For large circuits, there can be too many potential invariants requiring much time to prove. However, we observed that a large portion of them may not even contribute to equivalence checking. Moreover, equivalence checking can be significantly helped if there exists a method to check if a subset of potential invariants would be sufficient (e.g., whether two-nodes are enough or multi-nodes are also needed) prior to the verification step. Therefore, we propose two sufficiency-based approaches to identify useful invariants out of the initial potential invariants for SEC. Experimental results show that our approach can either demonstrate insufficiency of the invariants or select a small portion of them to successfully prove the equivalence property. Our approaches are quite case-independent and flexible. They can be applied on circuits with different synthesis techniques and combined with other techniques. / Master of Science