ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / Radio transmission channel influences greatly the quality of transmitted voice and data signal in terms of data rate and robustness. This degradation is as a result of many factors, notable amongst them are having multiple replica of the transmitted signal at the receiver (multipath), changes of frequency as a result of the movement of the aircraft (Doppler shift) and noise. This paper characterizes the scattered components of the aeronautical channel in terms of delay spread. Geometric representation is used to derive expressions for the maximum delay spread using the 2-ray model and the three dimensional model of the scattered path. Furthermore, the delay and Doppler frequencies are described as a function of the horizontal distance to the specular reflection point between a ground station and a test article. The simulated results are compared to measured data of related articles and the value of the maximum delay spread is compared with the proposed intersymbol guard band for Orthogonal Frequency Division Multiplexing (OFDM) in the Integrated Network Enhanced Telemetry (iNET) program to see if this proposition can be adapted to the aeronautical channel.

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Background: Shift work is associated with increased risk of cardiovascular disease and cancer, where decreased melatonin has been proposed as an intermediate in the causal pathway. The influence of physical activity on melatonin has rarely been studied in an observational setting, and it may be important in mediating the effects of shift work. We aimed to assess the influence of energy expended during physical activity of different intensities on melatonin among rotating shift nurses. We hypothesized that physical activity before the night shift would lessen the decrease in melatonin production that occurs with exposure to light at night. Methods: 123 female rotating shift nurses working at Kingston General Hospital were recruited over a one-year period. Physical activity and sedentary behaviours for each participant were recorded during both a day and a night shift using activity diaries, and analysis was restricted to activities between 3 p.m. and 7 a.m. Concentrations of urinary 6-sulfatoxymelatonin, a melatonin metabolite, in morning void urine samples were analyzed for each shift. Results: The average age of participants was 41 years, and 60% were overweight or obese (body mass index ≥ 25 kg/m2). An average of 6.9 and 5.2 hours of sleep were reported after the day shift and night shift, respectively. Sedentary behaviours such as standing and television watching accounted for over half of the total reported energy expenditure. During the day shift, energy expended in moderate and vigorous intensity physical activity between 3 p.m. and 7 a.m. was negatively associated with melatonin levels (p=0.024, R2 = 0.09). During the night shift, energy expended in sedentary behaviours was negatively associated with melatonin levels (p=0.008, R2 = 0.03). Conclusions: Physical activity energy expenditure explains only a small amount of melatonin variation, suggesting that other factors are influencing melatonin production, or that melatonin production is minimally effected by these patterns of physical activity. / Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2010-09-01 11:22:35.915

Background: In 2007, the International Agency for Research on Cancer classified shift-work involving circadian disruption as a “probable carcinogen.” One proposed pathway for this relationship involves nighttime light exposure and subsequent decreases in melatonin production. It is postulated that melatonin, a cancer-protective hormone, may influence patterns of sex hormone production that in turn influence breast cancer risk. The purpose of this study was to investigate the relationships between night shift-work history, melatonin and sex hormone levels among shift-working women. Methods: 82 pre-menopausal nurses who work a rotating shift pattern of two days (7AM-7PM), two nights (7PM-7AM), followed by five days off participated in two study periods approximately six months apart (in summer and winter), each taking place during a day shift of the normal rotating shift pattern. Creatinine-adjusted melatonin metabolite concentrations were measured from morning void urine samples, and estradiol, estrone, progesterone and prolactin concentrations were measured from fasting blood samples taken at the same time. Other pertinent information was collected by measurement (weight, height) and by self-report via questionnaire. We examined melatonin-sex hormone relationships within each of two seasons, and across seasons, to investigate two hypothesized latency periods for influences of melatonin levels on sex hormones. Multivariate linear regression was used to explore relationships, with adjustment for confounders including age and body mass index. Results: An inverse relationship between melatonin and estradiol was suggested in winter (β = -0.13, p = 0.11), and a positive relationship was suggested for increasing estrone with increasing melatonin tertile in summer (p = 0.07), after multivariate adjustments. Melatonin was not associated with other hormones in either season. On investigation of a longer latency period, melatonin in the first season was not associated with sex hormones in the second season. While those working night shifts for 20 years or more had higher mean levels of estradiol, estrone and progesterone, results were not statistically different from those with a shorter history of night work. Conclusions: The results of this study do not provide evidence to support the proposed biological pathway involving altered melatonin and sex hormone levels as intermediates between shift-work and breast cancer risk. / Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2010-09-14 11:42:06.201

Substantial numbers of Canadians work shifts. The reasons individuals work shifts are varied and complex. Prior research regarding the relationship between work-family balance, gender, quality of life indicators and health has yielded mixed results. The goal of this research was to examine the association between work-family balance, quality of life indicators and Canadians' overall health status while controlling for socio-economic status, education, family structure and life satisfaction. The two objectives of this study were: 1) to explore how the relationship between work-related characteristics, quality of life and overall health status is different among Canadian male and Canadian female workers, controlling for age, education, socio-economic status, family structure, and life satisfaction and, 2) to examine the relationship between shift configuration and employees' overall health status, controlling for socio-economic status, gender, education, family structure and life satisfaction. This study involved analyses of cross-secional national data from the General Social Survey (GSS) 2006, Cycle 20. The sample for the study included employed men and women who were married or living in common-law relationships, ages 18 through 69. Bivariate and logistic regression analyses were conducted to address the stated research objectives. Appropriate survey weights were applied to estimate population characteristeics. To fully account for the survey's complex sample design, mean bootstrap weights were used for variance estimation and calculation of confidence intervals. Findings indicated that for women and shift workers, both work-to-family spillover and family-to-work spillover were predictve of poor self-rated health. Spillover was not a predictor of poor health for men or day workers. Shift configuration was not found to be significantly correlated with poor self-rated health. Analyses should be repeated to test for interaction between shift work and sleep quality as sleep quality was controlled for in this study.

During the last several years, a fast growing interest in minimalist chic has been observed among fashion bloggers around the world. Many of them mention being tired of trends, a shift to inner values and a desire for more simplicity as a moving cause. Buying behaviour that is assumed to be sustainable requires a paradigm shift away from unbridled consumerism towards more mindful consumption. Understanding the current minimalist trend is a key to determining if in fact a paradigm shift is taking place, since that would have direct relevance for future fashion business models. This research aims to research and identify the motivations behind the changed way of dressing. It is discussed whether the new aesthetic is an indicator of an actual cultural shift. Finally, real minimalism is differentiated from the phenomenon of “faux-minimalism”. Specific attention is paid to the question whether a more simplistic wardrobe can lead to emotional liberation and increased happiness. 30 fashion blogs associated with minimalist style were observed to gather data that can give insights into the motivating causes for the phenomenon. To answer further questions, eight bloggers were interviewed. The gathered data from both observations and interviews was analysed and showed that the main reasons for minimalist style are both practical as well as emotional. On one hand, the bloggers cited limited space and finite financial resources. On the other hand, they discussed a desire to live a decelerated, simpler, more “authentic” life that prioritizes “being” rather than “having”.

Objective: Patient-reported outcomes (PROs) are measures collected from a patient to determine how he/she feels or functions in regards to a health condition. Longitudinal PROs, which are collected at multiple occasions from the same individual, may be affected by response shift (RS). RS is a change in a person’s self-evaluation of a target construct. Latent variable models (LVMs) are statistical models that relate observed variables to latent variables (LV). LVMs are used to analyze PROs and detect RS. LVs are random variables whose realizations are not observable. Factor scores are estimates of LVs for each individual and can be estimated from parameter estimates of LVMs. Factor scoring methods to estimate factor scores include: Thurstone, Bartlett, and sum scores. This simulation study examines the effects of RS on factor scores used to test for change in the LV means and recommend a factor scoring method least affected by RS. Methods: Data from two time points were fit to three confirmatory factor analysis (CFA) models. CFA models are a type of LVM. Each CFA model had different sets of parameters that were invariant over time. The unconstrained (Uncon) CFA model had no invariant parameters, the constrained (Con) model had all the parameters invariant, and the partially constrained (Pcon) model had some of the parameters invariant over time. Factor scores were estimated and tested for change over time via paired t-test. The Type I error, power, and factor loading (the regression coefficient between an observed and LV) and factor score bias were estimated to determine if RS influenced the test of change over time and factor score estimation. Results: The results depended on the true LV mean. The Type I error and power were similar for all factor scoring methods and CFA models when the LV mean was 0 at time 1. For LV mean of 0.5 at time 1 the Type I error and power increased as RS increased for all factor scores except for scores estimated from the Uncon model and Bartlett method. The biases of the factor loadings were unaffected by RS when estimated from an Uncon model. The factor scores estimated from the Uncon model and the Bartlett and sum scores method had the smallest factor score biases. Conclusion: The factor scores estimated from the Uncon model and the Bartlett method was least affected by RS and performed best in all measures of Type I error, statistical power, factor loading and factor score bias. Estimating factor scores from PROs data that ignores RS may result in erroneous (or biased) estimates.

Substantial numbers of Canadians work shifts. The reasons individuals work shifts are varied and complex. Prior research regarding the relationship between work-family balance, gender, quality of life indicators and health has yielded mixed results. The goal of this research was to examine the association between work-family balance, quality of life indicators and Canadians' overall health status while controlling for socio-economic status, education, family structure and life satisfaction. The two objectives of this study were: 1) to explore how the relationship between work-related characteristics, quality of life and overall health status is different among Canadian male and Canadian female workers, controlling for age, education, socio-economic status, family structure, and life satisfaction and, 2) to examine the relationship between shift configuration and employees' overall health status, controlling for socio-economic status, gender, education, family structure and life satisfaction. This study involved analyses of cross-secional national data from the General Social Survey (GSS) 2006, Cycle 20. The sample for the study included employed men and women who were married or living in common-law relationships, ages 18 through 69. Bivariate and logistic regression analyses were conducted to address the stated research objectives. Appropriate survey weights were applied to estimate population characteristeics. To fully account for the survey's complex sample design, mean bootstrap weights were used for variance estimation and calculation of confidence intervals. Findings indicated that for women and shift workers, both work-to-family spillover and family-to-work spillover were predictve of poor self-rated health. Spillover was not a predictor of poor health for men or day workers. Shift configuration was not found to be significantly correlated with poor self-rated health. Analyses should be repeated to test for interaction between shift work and sleep quality as sleep quality was controlled for in this study.

The development of a DC-DC converter for use in a proposed range of one to ten kilowatt off-line power supplies is presented. The converter makes good use of established design practices and recent technical advances. The thesis begins with a review of traditional design practices, which are used in the design of a 3kW, 48V output DC-DC converter, as a bench-mark for evaluation of recent technical advances. Advances evaluated include new converter circuits, control techniques, components, and magnetic component designs. Converter circuits using zero voltage switching (ZVS) transitions offer significant advantages for this application. Of the published converters which have ZVS transitions the phase shift controlled full bridge converter is the most suitable, and assessments of variations on this circuit are presented. During the course of the research it was realised that the ZVS range of one leg of the phase shift controlled full bridge converter could be extended by altering the switching pattern, and this new switching pattern is proposed. A detailed analysis of phase shift controlled full bridge converter operation uncovers a number of operational findings which give a better and more complete understanding of converter operation than hitherto published. Converter design equations and guidelines are presented and the effects of the new improvement are investigated by an approximate analysis. Computer simulations using PSPICE2 are carried out to predict converter performance. A prototype converter design, construction details and test results are given. The results obtained compare well to the predicted performance and confirm the advantages of the new switching pattern.

This thesis is concerned with attempts to establish solid-state NMR as a complementary technique to X-ray crystallography for providing information on crystal structure, i.e. information regarding conformation, packing and inter- or intra-molecular interactions. Methods of assigning the solid-state NMR spectrum have been used which rely upon (^1)H-(^13)C dipolar interactions and upon the shielding anisotropy experienced by the nuclei. Single pulse experiments have also been used to identify solvate molecules. Of particular importance, the anisotropy and asymmetry have been found for a number of steroids, and the values used to assign the high frequency region of the spectrum. This has enabled chemical shifts to be linked to the hydrogen bonds that are present. Thus, the mode of hydrogen bonding can be predicted in forms of cortisone acetate for which the crystal structure is not available. Chemical shifts have also been linked with the conformation of the D ring. In this way, important crystallographic information has been gleaned from the solid-state NMR spectrum. The effect of the formation of hydrogen bonds upon the shielding tensor components of carbonyl and ester carbons has been studied, and found to cause a high frequency shift in δ22, which is probably oriented along the C=0 bonds. This leads to a high frequency shift in the isotropic chemical shift. The effect of the spinning speed upon the centreband intensity of a peak as the anisotropy and asymmetry are varied has been investigated. It has been found that at low spiiming speeds, the centreband intensity does not vary in a simple fashion. Thus it is recommended that full shielding tensor analysis is performed. The effect of the spinning speed on the sample temperature has also been studied. Results show that at low spinning speeds (up to 2 kHz) there is sample cooling as the spinning speed increases (attributed to the Joule -Thompson effect). But at higher spinning speeds (above 2 kHz) then there is sample heating as the spinning speed increases. The importance of this result is discussed. The effect of quadrupolar nuclei (35C1 and (^14)N) upon the spectrum of a spin-(^1)(_2) nucleus ((^13)C) has been studied. In favourable cases, the anisotropy in the spin-spin coupling constant has been found, whilst in other cases, the sign and magnitude of the quadrupolar coupling constant have been obtained. The broadening of resonances of carbon atoms adjacent to quadrupolar nuclei has been valuable in assigning the solid-state NMR spectra. The broadening effect has also been observed at more distant sites. It has not been possible to distinguish the effects of (^37)C1 and (^35)C1 on the carbon spectra of chlorine containing steroids.