The geographical distance between home and workplace is present and increases within modern society. Along with changing economic structures and technological developments it has increased the spatial division of labour and changed the pressure on global, regional and local markets. Regional development strategies today emphasize on more mobile, flexible and larger geographical labour markets to improve matchmaking between jobs and labour force to reach and obtain development. Commuting has therefore increased and is often promoted as a positive solution for involved individuals and the regional society at large. Although, the notion and benefits of such regional development strategies have been questioned as commuting involves a consideration between economic and social circumstances and effects on all involved household members. The social and economic effects on commuting households in Umeå enlarged local labour market region have therefore been studied in and investigated in this thesis. Empirical data has been collected through qualitative interviews with four commuting households with different home-work locations and commuting situations. Results of this study goes in line with previous studies and pictures how commuting is a strategy to obtain or maintain desired living conditions within desired location when the local labour opportunities are limited. Commuting households therefore gain “quality of life” and labour opportunities. But, the economic benefits are reduced by transport costs and reduction of labour hours, and the social consequences of reduced time in the home environment effects relations between family members and the division of household responsibilities’. This study have also broaden the understanding of commuting effects and showed that shorter commuting distance also hold social and economic implications for commuting households.

Effective design of liquid fuel injection systems is a function of good understanding of liquid breakup mechanisms. A transient liquid breakup model is developed on the classical interfacial breakup theory by modifying the classical linear perturbation process to include time-dependent base and perturbed flow parameters. The non-isothermal condition on liquid jet instability and breakup is theoretically modelled; with the particular consideration of a spatially variation of surface tension along the liquid-gas interface. The model combines the classical interface hydrodynamic instability and breakup theory and heat-transfer through semi-infinite medium. Analytical liquid breakup model, which combines transient and non-isothermal effects on liquid jet breakup, is suggested. The suggested model could be simplified to the transient breakup model and the non-isothermal breakup model equivalents. A novel mechanistic model, which is based on a simple momentum balance between the injected jet and the aerodynamic drag force, is suggested for breakup length. A new model, which combines energy criterion and dual-timescale for turbulent shear in droplet dispersion, is suggested for droplet breakup criteria on the basis of critical Webber number. All developed models showed good predictions of available experimental data, and established empirical correlation, within the operational conditions of contemporary ICEs, specifically diesel engines. Continued research in these areas could benefit the development of the next generation of liquid fuel injectors and combustors – by accounting for transient effects and non-isothermal conditions in liquid jet breakup, and turbulent shear in droplet breakup.

Many studies suggest the ability of the NAIC Risk-Based Capital ratio (RBC ratio) to predict insurer insolvency. Based on the US life insurer (insurer) data for the period of 2005 to 2008, this study finds explanatory variables that have a statistically significant relationship with the RBC ratio. Advantages of panel data over cross-sectional and time series data analysis are exploited to make valid inference on coefficients of the explanatory variables. Testing for unobserved insurer and time effects and for dependence between these effects and the explanatory variables indicates the appropriateness of the fixed insurer and time effects model. Based on the ordinary least squares estimates, it is found that insurers' size, capital-to-asset ratio, and return on capital have a statistically significant relationship with the RBC ratio. Additionally, health product, annuity product, opportunity, and regulatory risks of insurers are related to the RBC ratio. Accounting for heteroscedasticity and autocorrelation for a given insurer yields the same coefficient estimates, but increased standard errors. / text

This dissertation addresses issues that arise in the classic linear instrumental variables (IV) model when some of the underlying assumptions are violated. / Economics

The Best Master's Thesis Award of the Hong Kong Section, American Society of Civil Engineers (2005-06) / published_or_final_version / abstract / Civil Engineering / Master / Master of Philosophy

published_or_final_version / Pathology / Master / Master of Philosophy

No description available.

The place of estrogen in women's health remains controversial. Premenopausal women have a lower prevalence of cardiovascular disease (CVD) than men and in observational studies hormone replacement therapy (HRT) decreases CVD in postmenopausal women. However, prospective randomized trials of secondary and primary prevention have failed to substantiate an overall protective effect from HRT and have even shown some harm. To explain this paradox it is necessary to better understand the effects of estrogen on the vascular wall. Estrogen rapidly mediates the activation of eNOS and increases the production of nitric oxide (NO), an important factor for endothelial health. In ovariectomized rats estrogen reduces production of superoxide (O2-) by NAD(P)H oxidase. The decreased function is associated with a decrease in the p47phox component of NAD(P)H oxidase and its interaction with the multicomponent enzyme. In these rats estrogen did not alter eNOS expression and bioavailability of NO, which is in contrast to its acute effects. This highlights the difference between chronic and acute studies. The decrease in O2-production suggests the intracellular signaling. / Estrogen has antiapoptotic effects. Oxidized low-density lipoprotein (oxLDL) and the inflammatory cytokine TNFalpha increased apoptosis which is associated with atherosclerosis. In human umbilical vein endothelial cells (HUVEC), estrogen decreased the extent of TNFalpha and oxLDL induced apoptosis as indicated by the expression of cleaved caspase-3 and FACS assay. Estrogen also preserves the antiapoptotic mitochondrial Bcl-2 and Bcl-xL proteins. / Estrogen has angiogenic properties that can help a healthy endothelium respond to injury. However, estrogen increases the angiogenesis caused by TNFalpha and this could lead to revascularization in the plaques of women with advanced disease. / Overall the balance between the positive and negative aspects of the effects of estrogen on the vascular wall could explain the paradoxical response in older women.

Adult rats produce two main types of ultrasonic vocalizations (USVs), occurring at 22 and 50 kHz USVs. These calls are associated with aversive and rewarding stimuli, respectively. The neural mechanism of amphetamine-induced calling was examined in lesion and antagonist studies. We also tested whether amphetamine-induced 50 kHz USVs could predict individual differences in intravenous self-administration or conditioned place preference behavior. Further experiments examined whether 50 kHz USVs could be evoked by amphetamine-conditioned sensory stimuli and by rewarding electrical brain stimulation. Overall, our experimental findings: (1) identify certain experimental conditions that increase amphetamine-induced 50 kHz calling, (2) provide evidence that these calls may be dependent on mesolimbic dopaminergic transmission, (3) relate individual differences in 50 kHz vocalizing to other behavioural measures of drug reward, and (4) show that in some situations, 50 kHz calls reflect anticipation of expected rewards.

<p>This thesis aims to measure the rate of radon loss from water in a systematic way. The dependence on surface area, temperature and concentration will be investigated. The experiments were done at UWC by creating radon using radium sources and then measuring the radon concentrations inside a vacuum chamber to obtain the speed of radon escape from the water. The results are compared to a model [Cal 2002] where the radon concentration in the air and hence the transfer rate is measured using a RAD7 radon detector. Since the equations cannot be solved analytically, a numerical solution is employed. The radon transfer velocity coefficient is found to be (1.9&plusmn / 0.5)&times / 10-6m/s. This value indicates that the escape of radon should not be a problem when a sample is open to the air for a minute or two.</p>