<p>Detta är en korrelationsstudie med avsikt att undersöka förhållandet mellan personlighetsegenskaper och kognitiva förmågor samt detta förhållandes inverkan på prestation. Studien är baserad på övningstestningar (n = 176) med WAIS-III, FAS, det lexikala beslutstestet SLDT samt personlighetsformuläret SSP, genomförda under informella former. Signifikanta negativa korrelationer förelåg mellan resultat på kognitiva test och personlighetsvariablerna Bitterhet, Somatisk Ångestbenägenhet, Psykisk Ångestbenägenhet, Stresskänslighet och Misstroende. Ett starkt positivt samband framkom mellan Somatisk ångestbenägenhet och antalet som riktiga ord skattade pseudoord i SLDT. Ett starkt negativt samband framkom mellan Bitterhet och samtliga skalindex i WAIS-III. Signifikanta negativa korrelationer förelåg vidare mellan en genom komponentanalys erhållen Neuroticism-faktor och resultat på WAIS-III. Jämförda med tidigare forskningsresultat är flera här redovisade korrelationer anmärkningsvärt starka. Som en bland flera tänkbara förklaringar till detta diskuteras möjligheten av stärkt ekologisk validitet vid testning under informella omständigheter. Vidare diskuteras bl a möjliga kopplingar mellan Somatisk ångestbenägenhet och alexitymi respektive verbal rigiditet samt mellan Bitterhet och flytande intelligens respektive exekutiva funktioner.</p>

<p>A method is developed for solving the two dimensional Helmholtz equation in a ductwith varying cross-section region bounded by a curved top and flat bottom, having oneregion inside. To compute the propagation of sound waves in a curved duct with a curvedinternal interface is difficult problem. One method is to transform the wave equation intoa solvable form and making the curved interface plane. To this end a local orthogonaltransformation is developed for the varying cross-sectional duct having one medium inside.This transformation is first used to make the curved top of the waveguide flat andto transform the Helmholtz equation into an initial value problem. Later on the local orthogonaltransformation is developed for a waveguide having two media inside with flattop, a flat bottom and a curved interface. This local orthogonal transformation is used toflatten the interface and also to transform the Helmholtz equation into a simple, solvableordinary differential equation. In this paper we present operator formulation for the partwith flat bottom and curved top including a curved interface. In the ordinary differentialequation with operators in coefficients, obtained after the transformation, all the operationsrelated to the transverse variable are treated as operators while the derivative withrespect to the range variable is kept.</p>

Background: Support for the four factor construct validity of the third edition of the Wechsler Adult Intelligence Scale (WAIS-III) has been found in clinical and non clinical populations but some studies question whether more complex models consistent with the concepts of fluid and crystallised intelligence provide a better explanation of the data. The WAIS-III is frequently used in the diagnosis of learning disability, however, previous exploratory factor analysis of data from a population with low IQ did not support the explicit four factor structure of the WAIS-III. Method: A confirmatory factor analysis of the WAIS-III was carried out on data from people with severe and significant learning disability and people with borderline IQ (IQ = 70-79). Results: The data from the borderline IQ sample and the sample with significant learning disability showed at best a weak fit to the explicit four factor models and more complex five or six factor models. However fit of the data from the sample with severe learning disability was poor for all models. Discussion: The findings show little support for the explicit four factor construct validity of the WAIS-III for people with borderline IQ or significant or severe intellectual impairment. Some support is found for the direction taken by the new Wechsler children’s and adult scales (WISC-IV & WAIS-IV) in aligning interpretation of the scales more closely to concepts such as fluid and crystallised theory. The research also suggests the cut-off point of IQ 70 is not reflective of an actual difference in cognitive profile as measured by the WAIS-III. Limitations of this study and implications for further research are also discussed.

III-V materials such as indium arsenide (InAs) and gallium arsenide (GaAs) are increasingly used in electronic and photovoltaic devices. The extensive application of these materials may lead to release of III-V ionic species during semiconductor manufacturing or disposal of decommissioned devices into the environment. Although arsenic is recognized as an important contaminant due to its high toxicity, there is a lack of information about the toxic effects of indium and gallium ions. In this study, acute toxicity of As(III), As(V), In(III) and Ga(III) species was evaluated using two microbial assays testing for methanogenic activity and 02 uptake, as well as two bioassays targeting aquatic organisms, including the marine bacterium Aliivibrio fischeri (bioluminescence inhibition) and the crustacean Daphnia magna (mortality). The most noteworthy finding was that the toxicity is mostly impacted by the element tested. Secondarily, the toxicity of these species also depended on the bioassay target. In(III) and Ga(III) were not or only mildly toxic in the experiments. D. magna was the most sensitive organism for In(III) and Ga(III) with 50% lethal concentrations of 0.5 and 3.4 mM, respectively. On the other hand, As(III) and As(V) caused clear inhibitory effects, particularly in the methanogenic toxicity bioassay. The 50% inhibitory concentrations of both arsenic species towards methanogens were about 0.02 mM, which is lower than the regulated maximum allowable daily effluent discharge concentration (2.09 mg/L or 0.03 mM) for facilities manufacturing electronic components in the US. Overall, the results indicate that the ecotoxicity of In (III) and Ga(III) is much lower than that of the As species tested. This finding is important in filling the knowledge gap regarding the ecotoxicology of In and Ga.

Nanoparticles (NPs) have unique electronic, optical and chemical properties due to the extreme small size. Engineered nanoparticles (ENPs) are intentionally produced for desired applications, with specific properties related to shape, size, surface properties and chemistry. Nano-sized silica (SiO2), alumina (Al2O3) and ceria (CeO2) are three important ENPs with large production and wide applications. One of the principal uses of these ENPs is in chemical and mechanical planarization (CMP), a key process applied to polish wafers when fabricating integrated circuits in semiconductor manufacturing, in which SiO2, Al2O3 and CeO2 NPs are used as abrasive particles in CMP slurries. CMP generates large amounts of waste effluents containing high levels of ENPs. Some ENPs have been proven to be able to cause toxicity to microorganisms and higher life forms, including humans. Therefore, there are concerns about the potential risks that ENPs may pose to the natural environment and human health. In addition, III-V materials like indium arsenide (InAs) and gallium arsenide (GaAs) are increasingly used in electronic and photovoltaic devices. Besides ENPs, the waste streams from III-V manufacturing also contain dissolved and particulate materials removed from III-V films during CMP. Arsenic is one of the most notorious contaminants that has been widely studied, while only very limited ecotoxicity information is available for gallium and indium. Finally, since ENPs have high surface area, it is very likely they will interact with the soluble species (such as arsenic ions) in CMP wastewater. Therefore, it is of great importance to understand whether the interactions between these materials could alter their fate and toxicity. The objective of this work is to investigate the potential environmental and health risks from the ENPs and III-V materials used in semiconductor manufacturing. To this end, the physical, chemical and toxicological characterization of ENPs used in CMP was performed (Chapter 3). Furthermore, the fate and transport of the most used ENP, SiO2, in porous media was studied (Chapter 4). In addition, acute toxicity of As(III), As(V), In(III) and Ga(III) species was evaluated using different bioassays (Chapter 5). Finally, the cytotoxicity of ENPs used in CMP slurries to human lung bronchial epithelial cells was evaluated using an impedance based real time cell analysis (RTCA) assay (Chapter 6). In Chapter 3, four model slurries containing ENPs including colloidal silica (c-SiO2), fumed silica (f-SiO2) cerium oxide (CeO2) and aluminum oxide (Al2O3) were characterized for their physical, chemical and toxicological properties. Ecotoxicity of these slurries to the marine bacterium, Aliivibrio fischeri, was evaluated by measuring its bioluminescence activity as a function of the ENP concentration dosed. The results showed that f-SiO2 and CeO2 were not toxic at concentrations up to 700 and 1000 mg/L, respectively. On the other hand, c-SiO2 and Al2O3 were inhibitory only at very high concentrations (>600 mg/L). At about 1300 mg/L, c-SiO2 and Al2O3 led to 37.6% and 28.4% decrease of cell activity after 30 min exposure, respectively. The inhibitory effect from c-SiO2 was related to additives in the slurry. In summary, the results indicate that these slurries are not likely to cause acute toxicity at environmentally relevant concentrations. The potential risks from ENPs are dependent on their fate and transport in the environment. In Chapter 4, the transport and abatement of SiO2 NPs was studied through laboratory scale column experiments. Synthetic fluorescent core-shell SiO2 NPs (83 nm) were used to facilitate NP traceability. Three widely used filtering materials, i.e., sand, anthracite and granular activated carbon (GAC), were used as porous media. Sand showed very poor capacity for the filtration of SiO2 NPs due to its limited surface area and high concentration of negative surface charge. In addition, the stability and transport of SiO2 NP was strongly dependent on the ionic strength of the solution. High ionic strength led to NP agglomeration and facilitated SiO2 NP retention, while low ionic strength resulted in release of captured NPs from the sand bed. Compared to sand, anthracite and GAC showed higher efficiency for SiO2 NP capture. The superior capacity of GAC was primarily due to its porous structure and high surface area. A process model was developed to simulate NP capture in the packed bed columns and determine fundamental attraction parameters. This model provided an excellent fit to the experimental data. Taken together the results obtained indicate that GAC is an interesting material for SiO2 NPs filtration. With the increasing usage of III-V materials, there are concerns about the ecological threats posed by III-V ions released during semiconductor manufacturing and from disposal of decommissioned electronic devices. In Chapter 5, the acute toxicity of As(III), As(V), In(III) and Ga(III) species was evaluated using different bioassays, including three microbial assays, testing for methanogenic activity, O2 uptake and bioluminescence inhibition of marine bacterium A. fischeri. Acute toxicity to the freshwater crustacean Daphnia magna was also tested. The results showed that In(III) and Ga(III) were generally not toxic or only mildly toxic in all assays, while both As(III) and As(V) showed strong inhibitory effects on different microbial activities (methanogenic and bioluminescence). The toxicity of these ions was strongly dependent on the bioassay target. For In(III) and Ga(III), D. magna was the most sensitive organism with 50% lethal concentrations (LC50) of 57.4 and 237.0 mg/L, respectively. On the other hand, As(III) and As(V) were particularly toxic to methanogens. The 50% inhibitory concentrations (IC50) of both species were about 1.5mg/L. Mixed aerobic heterotrophic culture was highly resistant to all four ions and O2 uptake by the aerobes was not affected in the tested concentrations. Overall, the results indicate that the ecotoxicity of In(III) and Ga(III) is much lower than that of the As species. This finding is important in filling the knowledge gap regarding the ecotoxicology of In and Ga. Besides ecotoxicity, ENPs and III-V materials in CMP effluents could also pose a threat to human health. In Chapter 6, the cytotoxicity of CMP slurries to human bronchial epithelial cells (16HBE14o-) was assessed using a novel impedance based real time cell analyzer (RTCA). Cell death and detachment was observed in assays supplied with high concentrations of c-SiO2 and f-SiO2 NPs (≥250 mg/L). On the other hand, CeO2 and Al2O3 slurries were not inhibitory at concentrations up to 1250 mg/L. In addition, since CMP wastewater generated during the planarization of III-V films contains a mixture of ENPs and soluble III-V species, it is important to understand whether the interactions between these materials could alter their fate and toxicity. As(III) toxicity to human lung cells in the presence and absence of CeO2 NPs was evaluated using the RTCA assay. Exposure to As(III) (0.5 mg/L) for 48 h resulted in 81.3% inhibition of cell viability and proliferation, while cell inhibition decreased to only 13.0% when As(III) was dosed together with sub-toxic levels of CeO2 NPs (250 mg/L). This detoxification effect was mainly due to As(III) adsorption onto CeO2 NPs. When the NPs were added, the soluble arsenic concentration was reduced significantly from 0.5 mg/L to 0.03 mg/L. This work demonstrates that adsorption of As(III) on CeO2 NPs can lower As(III) concentration in the solution and reduce its bioavailability and subsequently result in As(III) detoxification. In conclusion, this dissertation indicates that the ENPs (SiO2, CeO2 and Al2O3) used in semiconductor industry are not expected to cause acute toxicity to the natural environment and human health under environmentally relevant concentration (<1 mg/L). Among the soluble III-V species, In(III) and Ga(III) showed no or mild acute inhibitory effects in different bioassays even at comparatively high concentration. However arsenic species are highly toxic to various important microbial populations in the environment and human cells. The results showed that arsenic could induce toxic effects under current discharge limit set for semiconductor industry. Finally, we demonstrated that the adsorption of As(III) on CeO2 NPs can lower the concentration of soluble As(III) and subsequently resulted in As(III) detoxification.

The chemical fingerprints of old, metal-poor stars can be used to unravel the events of the newborn Universe and help us understand the properties of the first stars and star clusters. The study of nearby stars to infer properties in the distant past is often referred to as Galactic archaeology. However, the chemical composition of stars cannot be observed directly, but must be inferred by means of spectroscopic modelling. Traditionally, this modelling utilises one-dimensional (1D) stellar atmospheres in hydrostatic and local thermodynamic equilibrium (LTE). Today, we know that departures from LTE (known as NLTE), and differences between 1D model atmospheres and their hydrodynamical three-dimensional (3D) counterparts, become increasingly severe at lower metallicity. The development of NLTE modelling of spectral line formation in 3D atmospheres is still in its infancy, but constitutes a remarkable step forward that has been made possible by parallelised codes and supercomputers. The central theme of this thesis is the application of NLTE analyses to metal-poor stars, to help usher the field of Galactic archaeology forward with important consequences for the nature of the first stellar generations. I present a theoretical NLTE study of aluminium, where I validate the analysis using a set of bright standard stars and provide calculated NLTE effects for a large parameter space. I perform 3D NLTE calculations for the solar spectrum to better constrain the zero-point of the cosmic abundance scale, and find excellent agreement with the meteoritic aluminium abundance. I also present NLTE analyses of metal-poor stars in the globular clusters NGC 6397 and M4. While globular cluster stars were long expected to form from a chemically homogeneous medium, star-to-star abundance variations of light elements indicate multiple epochs of star formation. Massive first-generation stars polluted the interstellar medium from which later generations formed, and I use the observed abundance variations to deduce the properties of the polluting stars. Among the heavier elements, I uncover evolutionary abundance variations that match predictions of stellar evolution models with atomic diffusion. The results indicate that the chemical abundance ratios of unevolved metal-poor stars are affected by gravitational settling, with a bias of the order 25-50 %, increasing towards lower metallicity. This atmospheric depletion mechanism is a probable explanation to why the stellar abundances of lithium fall short of the predictions from standard Big Bang nucleosynthesis. Finally, I apply a 3D NLTE abundance analysis to the red giant SMSS 0313-6708, which is the most iron-deficient star known. The chemical abundance pattern of this star indicates that it formed from gas affected only by Big Bang nucleosynthesis and a single faint supernova. Comparison of the inferred abundance pattern to theoretical predictions leads to constraints on the explosion mechanism and the mass of the metal-free progenitor star.

The term procyclicality refers to the ability of a system to amplify business cycles. The recent financial crisis has revealed that the current regulatory framework, Basel II, affects the business cycle in exactly that manner. The newly published Basel III therefore sought to include tools that would mitigate the procyclical nature of regulatory framework. The aim of the thesis is to analyze whether such tools are effective and whether the procyclicality under Basel III has been mitigated when compared to Basel II. In order to conduct such analysis we employ a simple model with the households and firms sector. Using the OLS estimation method we estimate the sensitivity of Basel risk weights to the business cycle under both Basel II and Basel III conditions. As the Basel III framework has been published only recently, there are few studies that would analyze its effect on procyclicality. The main contribution of this thesis consists of implementation of Basel III countercyclical tools and the comparison between both frameworks. The thesis further contributes to the existing literature by conducting the analysis on the data for the Visegrád Group, that is for the Czech Republic, Slovakia, Hungary and Poland. JEL Classification E32, E44, E58, G21 Keywords procyclicality, Basel II, Basel III, banking...

In order to address the deficiencies in the banking regulation revealed by the recent financial crisis the Basel III introduces two minimum standards for funding liquidity, Liquidity Coverage Ratio (LCR) and Net Stable Funding Ratio (NSFR). The goal of this thesis is to analyze whether the NSFR is defined optimally or whether the Basel Committee on Banking Supervision (BCBS) will be forced to relax NSFR conditions similarly as happened by the LCR. Based on the approximation of the NSFR between 2007 and 2012 for a sample of 3 128 European banks we test the ability of banks to satisfy the NSFR. Our results suggest that the European banks have not started to converge to the NSFR yet. Despite this fact they should not have problems with meeting this requirement as 40.3% of banks in our sample would have already satisfied the NSFR in 2011. A Probit model analysis suggests that the NSFR requirement will decrease the probability of bank defaults and therefore increase the stability of the banking sector in the future which proves that the NSFR is correctly specified. Moreover, a simple stress testing shows that the stability of the system would not be improved anymore if the NSFR was defined more strictly. The current version of the NSFR therefore seems to be optimal and in our opinion should be...

This study assesses the impact of the Basel III regulatory framework on interbank contagion. It focuses on the direct interbank contagion that spreads via interbank foreign claims among national banking sectors. A balance sheet-based network model employs the quarterly consolidated banking statistics, collected by the Bank for International Settlements, to simulate the consequences of credit and funding shock under stressed market conditions. Compared to the Basel II, the Basel III regulatory framework reduces the probability of interbank contagion (following a simulated default of one banking sector) from 31% to 14% and lowers the impact of contagion by 63% in terms of average loss for a banking sector. The simulations under both regulatory frameworks show that relatively smaller banking sectors can trigger severe interbank contagion comparable to large banking sectors. Throughout the 2005-2009 period, the Basel III regulatory framework stabilizes the fluctuations of the scope of interbank contagion.

Non fourni / Non fourni