This thesis presents the synthesis, characterization and reactivity of a series of palladium complexes that contain redox-active verdazyl ligands. This work was motivated by the possibility of discovering new and interesting reactivity that may eventually lead to the development of new chemical reactions. A bidentate verdazyl radical ligand that contains an aryl phosphine was synthesized. Reaction of this ligand with (PhCN)2PdCl2 yielded a square planar (verdazyl)PdCl2 complex. Structural and spectroscopic data suggest that this compound consists of a ligand-centered radical coordinated to a Pd(II) center. The radical complex was chemically reduced by one-electron to generate a binuclear chloride-bridged [(verdazyl)PdCl]2 complex. In this reduced complex, both metals were still Pd(II) and the verdazyl ligand was determined to be in its singly reduced, monoanionic charge state. The original radical PdCl2 complex could be regenerated via one-electron oxidation of the reduced complex using PhICl2. The verdazyl ligands in the reduced complex could also be reversibly protonated to generate “leuco” verdazyl complex (verdazyl-H)PdCl2. Reaction of the radical (verdazyl)PdCl2 complex with water triggers a ligand-centered redox disproportionation reaction. A series of bis(verdazyl) palladium complexes were synthesized using a bidentate pyridine-substituted verdazyl ligand. Reaction of two equivalents of radical ligand with (CH3CN)4Pd2+ yielded a (verdazyl)2Pd(solvent)2+ complex (solvent = CH3CN or DMSO). In this complex, one verdazyl radical ligand chelates to palladium and the other binds as a monodentate ligand. Two-electron reduction of this complex generated a (verdazyl)2Pd complex in which two monoanionic verdazyl ligands are bound to a central Pd(II) ion. This reduced complex could also be made via reaction of 0.5 equivalents of Pd(0)2(dba)3 with two equivalents of radical ligand. In this reaction, the metal is oxidized by two electrons and each ligand is reduced by a single electron. Two-electron oxidation of the reduced complex in the presence of DMSO yielded the original bis(radical)complex, (verdazyl)2Pd(DMSO)2+. Chlorination of the reduced complex using one equivalent of PhICl2 (two-electron oxidation) resulted in dissociation of one verdazyl ligand to afford a 1:1 mixture of free verdazyl : (verdazyl)PdCl2, in which both of the verdazyls are neutral radicals. Reaction of the reduced complex with 0.5 equivalents of PhICl2 (one-electron oxidation) yielded a (verdazyl)2PdCl complex that contained a bidentate reduced verdazyl ligand and a monodentate radical ligand. All three of the oxidation reactions described above adhere to ligand-centered redox chemistry. Reaction of the reduced (verdazyl)2Pd complex with excess HCl resulted in protonation of both the anionic verdazyl ring and the pyridyl group to generate a leuco/pyridinium tetrachloropalladate salt, (verdazyl-H2)2(PdCl4). The protonated salt could be converted back to the original (verdazyl)2Pd complex by deprotonation with water. Palladium complexes of a tridentate NNN-chelating verdazyl ligand were prepared and their redox chemistry was explored. Reaction of the radical ligand with (CH3CN)4Pd2+ yielded radical complex (verdazyl)Pd(NCCH3)2+. The tridentate ligand was also prepared in its reduced, leuco form (verdazyl-H). Reaction of the leuco verdazyl with (CH3CN)2PdCl2 generated HCl and a (verdazyl)PdCl complex in which the ligand is in its monoanionic charge state. The reduced (verdazyl)PdCl complex was reacted with AgBF4 to afford (verdazyl)Pd(NCCH3)+ via chloride abstraction; the verdazyl remained in its reduced charge state following the reaction. Both reduced complexes (chloro and acetonitrile) were oxidized by a single electron to afford the corresponding radical complexes. These radical complexes could be reduced by a single electron to regenerate the original reduced complexes. Like the previous two projects, all of the redox chemistry was ligand-centered. The reactivity of these complexes with primary amines was also explored. Reaction of radical complex (verdazyl)Pd(NCCH3)2+ with n-butylamine resulted in one-electron reduction of the verdazyl ligand. We were unable to determine the mechanism of the reaction, but the reactivity that was observed demonstrates the potential for verdazyl-palladium complexes to be used in the design of new radical reactions. / Graduate / 2018-07-17

The bulk of the stellar growth over cosmic time is dominated by IR-luminous galaxies at cosmic noon (z = 1-2), many of which harbor a hidden active galactic nucleus (AGN). We use state-of-the-art infrared color diagnostics, combining Spitzer and Herschel observations, to separate dust-obscured AGNs from dusty star-forming galaxies (SFGs) in the CANDELS and COSMOS surveys. We calculate 24 mu m counts of SFGs, AGN/star-forming "Composites," and AGNs. AGNs and Composites dominate the counts above 0.8 mJy at 24 mu m, and Composites form at least 25% of an IR sample even to faint detection limits. We develop methods to use the Mid-Infrared Instrument (MIRI) on JWST to identify dust-obscured AGNs and Composite galaxies from z similar to 1-2. With the sensitivity and spacing of MIRI filters, we will detect >4 times as many AGN hosts as with Spitzer/IRAC criteria. Any star formation rates based on the 7.7 mu m PAH feature (likely to be applied to MIRI photometry) must be corrected for the contribution of the AGN, or the star formation rate will be overestimated by similar to 35% for cases where the AGN provides half the IR luminosity and similar to 50% when the AGN accounts for 90% of the luminosity. Finally, we demonstrate that our MIRI color technique can select AGNs with an Eddington ratio of lambda(Edd) similar to 0.01 and will identify AGN hosts with a higher specific star formation rate than X-ray techniques alone. JWST/MIRI will enable critical steps forward in identifying and understanding dust-obscured AGNs and the link to their host galaxies.

The first billion years of the Universe has been a pivotal time: stars, black holes (BHs), and galaxies formed and assembled, sowing the seeds of galaxies as we know them today. Detecting, identifying, and understanding the first galaxies and BHs is one of the current observational and theoretical challenges in galaxy formation. In this paper we present a population synthesis model aimed at galaxies, BHs, and active galactic nuclei (AGNs) at high redshift. The model builds a population based on empirical relations. The spectral energy distribution of galaxies is determined by age and metallicity, and that of AGNs by BH mass and accretion rate. We validate the model against observations, and predict properties of galaxies and AGN in other wavelength and/or luminosity ranges, estimating the contamination of stellar populations (normal stars and high-mass X-ray binaries) for AGN searches from the infrared to X-rays, and vice versa for galaxy searches. For high-redshift galaxies with stellar ages <1 Gyr, we find that disentangling stellar and AGN emission is challenging at restframe UV/optical wavelengths, while high-mass X-ray binaries become more important sources of confusion in X-rays. We propose a color-color selection in the James Webb Space Telescope bands to separate AGN versus star-dominated galaxies in photometric observations. We also estimate the AGN contribution, with respect to massive, hot, and metal-poor stars, at driving high-ionization lines, such as C IV and He II. Finally, we test the influence of the minimum BH mass and occupation fraction of BHs in low-mass galaxies on the restframe UV/near-IR and X-ray AGN luminosity function.

Automated human activity recognition has attracted increasing attention in the past decade. However, the application of machine learning and probabilistic methods for activity recognition problems has been studied only in the past couple of years. For the first time, this thesis explores the application of semi-supervised and active learning in activity recognition. We present a new and efficient semi-supervised training method for parameter estimation and feature selection in conditional random fields (CRFs),a probabilistic graphical model. In real-world applications such as activity recognition, unlabeled sensor traces are relatively easy to obtain whereas labeled examples are expensive and tedious to collect. Furthermore, the ability to automatically select a small subset of discriminatory features from a large pool can be advantageous in terms of computational speed as well as accuracy. We introduce the semi-supervised virtual evidence boosting (sVEB)algorithm for training CRFs — a semi-supervised extension to the recently developed virtual evidence boosting (VEB) method for feature selection and parameter learning. sVEB takes advantage of the unlabeled data via mini-mum entropy regularization. The objective function combines the unlabeled conditional entropy with labeled conditional pseudo-likelihood. The sVEB algorithm reduces the overall system cost as well as the human labeling cost required during training, which are both important considerations in building real world inference systems. Moreover, we propose an active learning algorithm for training CRFs is based on virtual evidence boosting and uses entropy measures. Active virtual evidence boosting (aVEB) queries the user for most informative examples, efficiently builds up labeled training examples and incorporates unlabeled data as in sVEB. aVEB not only reduces computational complexity of training CRFs as in sVEB, but also outputs more accurate classification results for the same fraction of labeled data. Ina set of experiments we illustrate that our algorithms, sVEB and aVEB, benefit from both the use of unlabeled data and automatic feature selection, and outperform other semi-supervised and active training approaches. The proposed methods could also be extended and employed for other classification problems in relational data. / Science, Faculty of / Computer Science, Department of / Graduate

This thesis explores the use of active inductors as a compact alternative to the bulky passive spiral structures in high-speed I/O circuits. A newly proposed PMOS-based topology is introduced and used in active-inductor terminations. The 1st prototype design fabricated in a 90-nm CMOS process consists of an output driver using active-inductor terminations to provide channel equalization and output impedance matching. From measurement results, the use of active inductors in the termination, as compared to when the active inductor is disabled, increases the vertical eye opening in the receiver side by a factor of two and reduces the jitterp-p by 30% of the transmitted 10 Gb/s (2³¹-1) pseudo-random binary sequence pattern, over a 6-inch FR4 channel. An output impedance matching with S₂₂ less than -10 dB over a bandwidth of 20 GHz is achieved. The pair of active-inductor terminations occupies 17×25 µm² and has a low overhead power consumption of 0.8 mW. In the 2nd prototype design, a 4-stage output buffer with active-inductor loads is designed and implemented in a 65-nm CMOS process. Simulation results verify that when operating at 31.25 Gb/s, the output eye of the active-inductor load buffer compares favorably with that of the passive-inductor load buffer. For a similar eye-height and 78% less timing jitter the active-inductor load design’s speed (31.25 Gb/s) is 25% faster than the passive-resistor load design (25 Gb/s). The active-inductor load output buffer achieves comparable performance in terms of speed, power, and output swing with other reported designs using passive inductors. Its total area is 135×30 µm² (including three differential active inductors) which is comparable to the size of a single passive spiral inductor having a 0.5~1 nH inductance. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

This is the second paper in a series on a new luminous z similar to 5 quasar survey using optical and near-infrared colors. Here we present a new determination of the bright end of the quasar luminosity function (QLF) at z similar to 5. Combining. our 45 new quasars with previously known quasars that satisfy our selections, we construct the largest uniform luminous z similar to 5 quasar sample to date, with 99 quasars in the range of 4.7 <= z < 5.4 and -29 < M-1450 <= -26.8, within the Sloan Digital Sky Survey (SDSS) footprint. We use a modified 1/V-a method including flux limit correction to derive a binned QLF, and we model the parametric QLF using maximum likelihood estimation. With the faint-end slope of the QLF fixed as alpha = -2.03 from previous deeper samples, the best fit of our QLF gives a flatter bright end slope beta = -3.58 +/- 0.24 and a fainter break magnitude M-1450(*) = -26.98 +/- 0.23 than previous studies at similar redshift. Combined with previous work at lower and higher redshifts, our result is consistent with a luminosity evolution and density evolution model. Using the best-fit QLF, the contribution of quasars to the ionizing background at z similar to 5 is found to be 18%-45% with a clumping factor C of 2-5. Our sample suggests an evolution of radio loud fraction with optical luminosity but no obvious evolution with redshift.

This phenomenological study explores how certain “innovative” pedagogies were experienced by a group of Chinese students studying Business Management at a mid-ranking UK university. Analysis of the transcripts of interviews (some in Chinese) with 24 students using NVivo shows that whilst most students felt that Active Learning pedagogies effectively supported their learning, for some students the “zone of indeterminacy” in which group projects and simulations were carried out was an uncomfortable space. Salient aspects of these students’ experiences were language, relationships and metacognitive skills, and the discussion explores the way in which these three experiential themes can be conceptualised as interrelated elements of the action (Biesta, 2006) which takes place in Active Learning classrooms. The following recommendations are made: HEIs should attempt to provide students with the advanced skills of negotiation which they will need to use in the flexible, ill-structured environments associated with Active Learning pedagogies; tutors should develop consistent approaches to collaborative assignments focussing on group work processes as well as task completion; the development of metacognitive skills through Active Learning pedagogies should be promoted through the use of explicit reflective elements embedded within the teaching, learning and assessment activities. The concluding discussion proposes that the successful use of Active Learning pedagogies requires a reconceptualisation of the purpose of education and that these pedagogies provide a potential readjustment of the balance between the functions of qualification, socialisation and subjectification (Biesta, 2010).

Thesis (MPH.) -- University of Limpopo, 2015 / Purpose / Aim: To find out determinants affecting adherence to antiretroviral therapy in patients receiving free treatment from the wellness clinic at Bela Bela District Hospital in Limpopo province of South Africa. Objectives: To identify the determinants which affect the adherence to ART treatment among patients living with HIV and AIDS and to determine which of these determinants are significant predictors of adherence among HIV and AIDS patients. Methodology: a descriptive retrospective, quantitative research. Sampling: A population of 800 patients existing in the recording book was retrieved from the patients’ records at the wellness clinic. Out of 800 a sample of 260 was derived using a simple size calculator tool. Analysis: data were analysed by SPSS Windows Version 21.0. Descriptive statistics means and frequencies were calculated. Chi-Square tests were done in order to test the association between variables (such as age groups, gender, weight groups, regimens and WHO stages). Logistic regression was run to assess the effect of different determinants on the adherence to ART (e.g. viral load affected the adherence contrary to age, gender and others). Results: Female (65%) was more compliant to their male counterpart (35%). Most of the patients (47.3%) in the study belonged to the age group 21 to 35 years and only (2.7%) in the age group less or equal to 20 years. Most patients were categorised into WHO stage I (31.2%). Only 9.2% of the patients were categorised into WHO Stage IV. Most of the patients in group 2 (41.3%) had a weight between 40kgs and 54kgs and group 1 (4.2%) with patients whose weight was less than 40kgs. One of the patients has no record on weight. The majority of patients (44.2%) had CD4 count, less or equal to 100. Only 2.7% had CD4 count 300 and more. After 6 months of treatment, 37% of patients had CD4 count from 300 and above; 9.7% of the patients had CD4 countless than 200. For 136 (52.3%) of the patients in the sample the information on CD4 count at 6 xi months was missing. The majority of patients (72.7%) in the sample had low viral load and only (27.3%) of the patients had high viral load. Majority of patients (48.5%) were on New 1a Regimen instead of Regimen 1a (30.8%) because of the side effects the latter has on them. Some patients (11.2%) were on Regimen 1b, followed by patients (8.1%) on Regimen New 1b. The remaining patients were on Regimen 1c, Reg 2 and Truvada (1.6%). Findings: The majority of patients were young females; in the age-group of 21-35 years. This is reproductive age with many challenges: earlier exposed to infection, more vulnerable than males, stigmatisation, rape, fear of isolation. Majority of patients were in the WHO stage 1 and 2. The WHO stage does not depend on the level of CD4 count. It is important to consider the weight of the patient before to initiate the treatment. More than the half patients had a CD4 count required to start with ART. After 6 months they were more adherent. Most of them were on regimen Reg (New 1a) because of less side effects. The findings showed also different types of associations with some variables were significant determinants such as CD4 count had significant associations with gender, viral load, regimen, WHO staging, the p-value was lesser than 0.05. Conclusion: The results showed that viral load was the only determinant affecting adherence in the current study. The number of males in this study population was lower than females from the age group of less than 20 and age group of 21 to 35, and females than males in age group 36 to 50 and 51 or more. The lower infectivity of males is linked to the state of denial and not testing for HIV. The lower number in females can be due to their positive trends to the ART in their old age. The reasons for the low number need to be investigated. Awareness campaigns should be intentioned towards males. There should be publicity about the equality of both male and female genders.

This thesis focuses on private information dissemination and its impacts on financial markets. Specifically, we study issues arising when there are skilled individuals able to extract anticipative information about future prices. The first model considers a continuous time economy that is populated by informed and uninformed investors as well as active unskilled investors, and investigates the existence of noisy rational expectations equilibria and their properties. Equilibria are derived in closed form and their properties analyzed. Informed trading is found to reduce price volatility. The second model is based on the idea that besides exploiting their private information for trading purposes, informed agents might want to offer wealth management services to uninformed investors in exchange for a fee. A market for active funds emerges, and the process of anticipative information dissemination is endogenized. In this chapter, heterogenous risk averse investors can invest in the active fund. Low risk tolerance investors are found to be strictly better off with the active fund. Fund size is not a reliable indicator of managerial skill. The market reacts to the manager's increasing risk-taking behavior by reducing the volatility and risk premium.

This master’s thesis is focused on the design of a functional reliable computer network for primary school. The master ‘s thesis analyses the current state of the communication infrastructure of the primary school and the own solution is implemented based on this analysis. Part of the solution deals with implementation of an application for distance education and the basic setup of the school computer server. The master ‘s thesis contains the design of cable routing routes, selection of active elements, Gantt chart of the project and economic evaluation of the whole project.