[pt] Esse trabalho trata da determinação da atenuação de um enlace radioelétrico em microondas que utiliza um sistema duplo-passivo em região Fresnel de uma antena parabólica adjacente. Com esse objetivo são apresentados os valores do ganho diferencial da configuração para dois casos distintos: a) Repetidores passivos planos com abertura regulares iguais. b) Repetidores passivos planos com abertura quadradas desiguais. Com base nos resultados obtidos para esses dois casos são apresentadas também as curvas do ganho diferencial para a situação em que o sistema duplo-passivo se encontra em região de Fraunhofer da antena parabólica, podendo as mesmas, para uma situações tratadas, ser comparadas com aquelas obtidas por Yang2. Considerou-se campo elétrico sobre a abertura da antena parabólica excitadora polarizado linearmente e da forma 4,5,7 Ea = EO (1 - ar 2) onde r = p /R é a variável radial normalizada e, para uma atenuação de bordas de 10 dB, o parâmetro (alfa) é igual a 0,684. / [en] This theoretical study gives the propagation loss through a microwave radio relay system using doublé-passive configuration in the Fresnel zone of the exciting parabolic antenna. Two cases are treated separately: a) Plane passive repeaters with equal rectangular apertures. b) Plane passive repeaters with nonequal square apertures. Based on the results obtained for the two above cases the curves for the relative gain of a doublé-passive in the Fraunhofer region of the exciting antenna are derived and, for case b, can be checked with those by Yang2.. assuming a constant-phase, symmetrical illumination of the exciter aperture, the source field can be expressed as a function only of the radial variable: Ea = EO (1 - ar 2) where r = p/R is the normalized radial variable and (alfa) = 6.864 to produce the common 10 dB taper.

The work presented in this thesis was undertaken to explain the differences in output powers and small-signal gain coefficients observed in cw N20 and C02 lasers. To isolate the factors limiting small-signal gain, the dynamics of conventional cw N20 laser discharges were investigated using a tunable diode laser (TDL) operating in the 2120-2350 cm-1 frequency region. Absorption measurements were made with the TDL on more than 10 different vibrational bands, allowing vibrational population distributions in the three normal modes of vibration of N20 to be determined. The vibrational populations follow a Boltzmann distribution, and the v1 and v2 mode temperatures are found to be strongly coupled, and to maintain equilibrium with the background gas temperature under all discharge conditions. It is observed that the v3 mode temperature saturates at high discharge currents. This saturation, which is attributed to electron de-excitation, is determined to be the primary factor limiting small-signal 10-μm gain in the N20 laser and is much more important than N20 dissociation. The maximum small-signal gain coefficients achievable in cw N20 lasers are calculated, and the results of the work indicates the measures that must be taken to optimize small-signal gain in the N20 laser. / Thesis / Master of Science (MSc)

Prolonged second stage of labor, excessive gestational weight gain and cesarean delivery has been associated with adverse maternal and fetal outcomes. Physical activity during pregnancy is a modifiable risk factor which has never been studied among Hispanic women. Gestational weight gain, another modifiable risk factor has only been evaluated as a risk factor for cesarean delivery in two studies among women induced for labor. To date, no study has examined the effect of duration of second stage of labor on intra-ventricular hemorrhage in very preterm births. We examined these maternal risk factors for prolonged second stage of labor, rate of cesarean delivery and fetal outcomes. The first study evaluated the association between physical activity and duration of second stage of labor. Prior studies regarding physical activity and duration of second stage of labor have been conflicting and none have examined the Hispanic population. During pregnancy, activities such as household chores, childcare, sports and women's occupation constitute a significant proportion of physical activity but have not been considered in prior studies. We examined the association between total physical activity (occupational, sport/exercise, household/care giving, and active living) during pre, early and mid-pregnancy and duration of second stage of labor in a prospective cohort of 1,231 Hispanic participants. Physical activity was quantified using the Kaiser Physical Activity Survey administered during pregnancy. Using multivariate linear regression we did not find statistically significant association between pre, early and mid-pregnancy physical activity and duration of second stage of labor. The second study focused on the effect of gestational weight gain on the cesarean delivery rate after induction of labor. The rate of induction of labor (IOL) has more than doubled from 9.5% in 1990 to 22.5% in 2006. Cesarean delivery usually follows a failed IOL and is associated with maternal and fetal morbidity. One of the two studies evaluating the effect of gestational weight gain on the rate of cesarean section in patients undergoing IOL was restricted to women with normal Body Mass Index (BMI) and the other was subjected to bias because more than half of the patients were missing BMI data. Therefore, we evaluated the effect of gestational weight gain on the rate of cesarean delivery after labor induction. In a retrospective cohort study design, using data from May 2005 to June 2008 and a multivariate logistic regression we found a 13% increase in risk of cesarean delivery with 5 kg increase in gestational weight gain. Finally, we evaluated the effect of mode of delivery and duration of second stage of labor on intra-ventricular hemorrhage (IVH) among early preterm births. IVH is a serious complication associated with preterm birth and important predictors of cerebral palsy and neurodevelopmental delays. Prior studies on this relationship in early preterm births are sparse. In a retrospective cohort study of newborns born less than 30 weeks or less than 1500 g between May 2003 and August 2008, we found an increase in risk of IVH after vaginal delivery. However, duration of second stage of labor had no significant effect on risk of IVH.

Annual ryegrass (Lolium multiflorum Lam.) can be divided into two cytotypes: diploid (2n = 2x = 14) or tetraploid (2n = 4x = 28). Transforming annual ryegrass from diploid to tetraploid often results in increased seedling vigor, more robust growth and, thus, supposedly greater yield. There has been conflicting research that suggests no difference in yield between diploid and tetraploid cultivars, but livestock producers’ question whether benefits exist to utilizing tetraploid cultivars for grazing cattle. This study sought to determine if annual ryegrass cytotype affected cattle average daily gain. Although there were no differences in average daily gain between cytotypes, there were differences among cultivars. In 2017, Jumbo (4x) produced the greatest weight gain, while in 2018, Tam-90 (2x) generated the greatest gain. This study suggests that there are no advantages attributed to average daily gain by utilizing tetraploid, as opposed to diploid cultivars.

<p> Compositionally asymmetric multiple quantum well (AMQW) lasers are used for the demonstration of the gain flattening coating functionality. The gain spectra of the lasers are extracted using a non-linear least square fitting method. An optimum facet reflectance spectrum is calculated for a chosen current. For manufacturability, a modified reflectance spectrum of the gain flattening coating is proposed, in order to achieve operation over a wider spectral range without the 'difficult' gap which was a region where lasing was difficult or impossible to achieve due to insufficient gains at these wavelengths. </p> <p> Silicon oxides films with high, medium, and low refractive indices fabricated in an inductively coupled plasma (ICP) enhanced chemical vapor deposition (CVD) system are chosen as the building blocks of the gain flattening coating. An 18-layer coating is designed by the insertion of needle-like refractive index variation with a few optimization methods applied to minimize the merit function. A laser bar holder is custom designed and fabricated. Experiments and modification on the laser bar holder are carried out for better performance. The 18-layer gain flattening coating is then fabricated in the ICPCVD system with an in-situ spectroscopic ellipsometric measurement. It is observed that the non-lasing gap has disappeared after the coating is applied. Without external feedback, the coated laser shows tuning over 85 nm with the central wavelength of 1593 nm, while the uncoated laser has a non-lasing gap of about 25 nm in the central region of the tuning range of 70 nm. </p> <p> Finally, the coherence length of a low coherent source synthesized from the gain flattening coated AMQW laser is measured by using Michelson interferometer. The highest depth resolution that can be achieved is measured as 40 μm. The power intensity of the synthesized low coherence light source from the gain flattening coated AMQW laser is rendered from the interferogram using fast Fourier transform (FFT). </p> / Thesis / Doctor of Philosophy (PhD)

Spontaneous parametric down-conversion (SPDC) is a nonlinear optical process in which an incident field known as the pump interacts with a nonlinear crystal to produce two output fields known as signal and idler. Due to the conservation of energy and momentum, these output fields are entangled in the temporal and spatial degrees of freedom. The gain, which represents the strength of the interaction, increases in direct proportion to the strength of the pump field. In the low-gain regime, the generated field is an entangled two-photon state. This regime continues to be routinely employed in fundamental quantum optics experiments and quantum technologies. In the high-gain regime, the generated field is a multiphoton entangled state known as a bright squeezed vacuum. The goal of this thesis is to theoretically and experimentally characterize the spatial correlations present in high-gain SPDC. In order to characterize the spatial correlations between the generated fields, we utilize the Schmidt decomposition formalism. In this study, we examine the evolution of the Schmidt modes and spectrum with increasing pump amplitude. Our work shows that the Schmidt modes expand marginally in size, and the Schmidt spectrum narrows with respect to increasing gain. The narrowing of the Schmidt spectrum, as quantified by a decrease in the Schmidt number, indicates a gradual decrease in spatial entanglement.

Multiple-in multiple-out (MIMO) is a wireless communication technique where antenna arrays, at the receiver and transmitter, utilize signal multipath propagation to increase data throughput capacity. The unique benefits MIMO provides have over the last 20 years led to the steady increase in usage in both Wi-Fi and mobile networks. Predicting the performance of an antenna array designed for MIMO is more difficult than predicting the performance of a single antenna. This is due to the increased performance deriving from the processed combination of information from each antenna element. To determine the increased benefits that additional antenna elements can provide to a wireless system, the statistical correlation between the signals received from all antenna element needs to be evaluated. This correlation is expressed with the correlation coefficient $\rho$. The correlation coefficient may be estimated from the far field radiation pattern measured in an anechoic chamber, or measured from the statistically isotropic and homogeneous radiation environment provided by a reverberation chamber. However, Blanch, et al. 2003, proposed a much simpler method to estimate the correlation coefficient using a Vector Network Analyzer (VNA) to measure scattering parameters (S-parameters) while assuming perfect antenna efficiency. In 2005 Hallbjörner proposed a modified version of the estimation including the effect of antenna efficiency. This project aimed to measure and compare the results from the two types of chamber tests along with the two S-parameter based approximation methods mentioned. To accomplish this, three different antenna arrays, with four elements each with varying efficiency and mutual coupling, were designed and manufactured. The antenna arrays were then measured in an anechoic chamber, in a reverberation chamber, and had their S-parameters determined with a VNA. From the measurements it was found that the results from both types of chamber tests agree well, indicating that both tests are viable methods of signal correlation estimation. The S-parameter method proposed by Blanch was found to be inaccurate for the antennas tested, likely due to low radiation efficiencies. However, the approximation method proposed by Hallbjörner produced better results, but requires the efficiencies of the antennas which is generally not simple to determine. In conclusion it is found that S-parameter measurements, which are commonly used by the wireless industry, do not provide valid estimates of the MIMO performance of antenna arrays unless they are complemented with measurements of antenna efficiency. / <p></p><p></p><p></p>

The growing use of social media has facilitated the rapid spread of content, factual or not, and has fueled a culture built on followers and likes. Clinicians have reported increasing trends of illnesses and disorders among individuals who view content on such conditions. One of the reasons for this is faking for secondary gain, even to the extreme of Factitious Disorder. The aim of this study is to augment the literature on individuals who feign illnesses or their severity on social media. Participants (N=533) completed a survey consisting of demographic questions, questions about faking behaviors in relation to social media, their social media usage, the Abbreviated Marlow-Crowne Social Desirability Scale, Dark Triad Scale, and Leary Need to Belong Scale. Individuals with high-faking behaviors exhibited significantly higher psychopathy and a lower need to convey social desirability than individuals exhibiting no faking behaviors. By conducting further research and gaining a deeper understanding of these individuals, effective treatments can be provided leading to a possible decrease in the prevalence of such illnesses and disorders.

Maternal weight during pregnancy has an important impact on multiple aspects of health for both mothers and their children. This dissertation investigated whether pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) independently impact a child’s health service utilization. Methods: This dissertation included four studies. The study population for the first three studies was all women who delivered a singleton, live infant in Ontario between 2012-2014 and have information contained in the Better Outcomes Registry and Network (BORN) Ontario registry. Health service data in the first 24 months following birth were collected via health administrative databases housed at ICES. I investigated whether there was an association of pre-pregnancy BMI (Chapter 2) or GWG (Chapter 3) with pediatric health service use. I then investigated whether adverse birth outcomes, specifically small for gestational age (SGA) or preterm birth (PTB), mediated this relationship (Chapter 4). Finally, I developed a cost effectiveness evaluation framework for the implementation of a maternal weight intervention program to limit the impact on the child (Chapter 5).Findings: Children born to women with pre-pregnancy obesity relative to normal weight experienced higher rates of hospitalization (adjusted incidence rate ratio [aIRR]: 1.20, 95% CI:1.17,1.24), physician visits (aIRR: 1.05, 95% CI: 1.04,1.05) and emergency department (ED)visits (aIRR: 1.27, 95% CI: 1.25,1.29). Children born to normal weight (aIRR: 1.07, 95% CI:1.05,1.09) or overweight (aIRR: 1.04, 95% CI: 1.01,1.07) mothers with above recommended (versus recommended) GWG had increased ED visits. Children born to underweight women with below recommended GWG had increased hospitalizations (aIRR: 1.31, 95% CI: 1.14,1.51) and physician visits (aIRR: 1.14, 95% CI: 1.10,1.17). PTB (56.74%), and SGA (6.83%)iv mediated the relationship of below recommended GWG and pediatric hospitalizations only. Adetailed cost effectiveness framework is outlined to investigate an intervention plan targeting GWG to limit adverse pediatric health outcomes. Discussion: The findings of this dissertation indicate that below or above optimal maternal weight is associated with pediatric health service use. This dissertation serves as a call to action to better inform clinical practice and impact health service policy related to maternal weight via early intervention.

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