When groups of individuals make choices among several alternatives, the most compelling social outcome is the Condorcet winner, namely the alternative beating all others in a pair-wise contest. Obviously the Condorcet winner cannot be overturned if one sub-group proposes another alternative it happens to favor. However, in some cases, and especially with haphazard voting, there will be no clear unique winner, with the outcome consisting of a triple of pair-wise winners that each beat different subsets of the alternatives (i.e. a “top-cycle”.) We explore the sensitivity of Condorcet winners to various perturbations in the voting process that lead to top-cycles. Surprisingly, variations in the number of votes for each alternative is much less important than consistency in a voter’s view of how alternatives are related. As more and more voter’s preference orderings on alternatives depart from a shared model of the domain, then unique Condorcet outcomes become increasingly unlikely.

Recent experimental investigation on FSS arrays forming waveguides (FSGs) and horns showed that incident electromagnetic energy can be guided and radiated at specific frequencies. This thesis aims to provide the theoretical understanding of the waves propagating inside a cylindrical FSS waveguide. With immediate applications on horn antennas the research deals with cylindrical guides, made entirely from double periodic arrays. The theoretical analysis begins as a standard electromagnetic boundary value problem. The formulated system of algebraic equations is solved either for the complex propagation constant, by an iterative procedure or, for the fields. The analysis makes use of the Floquet modal expansion, the current representation as a set of sub-domain basis functions and the Method of Moments. Initially, the thesis is concerned with single periodic structures, which is a special case to the analysis. The efficiency of the model to provide stable and valid results is examined. Next the elements are finite dipoles. The effects of the dipole resonance to the propagating and radiating characteristics of the FSS is closely investigated. Other aspects include the effects of the periodicity and the element size. The investigation concludes with an FSG with square loop elements. Validation of the results for some designs is made by comparison with measured data.

Comparison of Top trees implementations - Abstract Jiří Setnička Definition and description of Top trees and introduction of problems solvable by them including problem of edge 2-connectivity. Definition and description of Topology trees used as one of the drivers for Top trees. After the initial descriptions the two top trees implementations are introduced: one based on self adjusting trees, second based on topology trees. Comparison of these implementations is done by two experiments. Measurements are discussed in conclusion - results corresponds with initial estimates but with different multiplicative constant than expected. 1

Die Entdeckung des Higgs-Bosons im Jahr 2012 bestätigt das Standardmodell als die erfolgreichste Theorie, die die grundlegenden Wechselwirkungen von Elementarteilchen beschreibt. Eine der wichtigen Eigenschaften des Higgs-Bosons ist seine Yukawa-Kopplung an das Top-Quark, die aufgrund der hohen Masse des Quarks im Standardmodell am stärksten ist. Diese Arbeit berichtet über eine Messung der Top-Yukawa-Kopplung mit Daten, die vom ATLAS-Detektor von 2015 bis 2018 bei einem Massenschwerpunkt von 13 TeV aufgezeichnet wurden. Die Kopplung wird in ttH(bb)-Ereignissen untersucht, einem Endzustand, der die Zerfälls-produkte von zwei Top-Quarks enthält und in dem zusätzlich ein Higgs-Boson emittiert wird, welches in Bottom-Quark-Paar zerfällt. Dieser Zerfallskanal des Higgs-Bosons hat das größte Verzweigungsverhältnis, wird jedoch durch die Beschreibung des dominanten Untergrundprozesses ttbb, ein Top-Quark-Paar mit zwei zusätzlichen b-Quarks im Endzustand systematisch beschränkt. Die Messung nutzt die Fähigkeit des ATLAS-Detektors, Jets von einem b-Quark zu identifizieren, um Analysebereiche mit verschiedenen Zusammensetzungen von Signal und Untergrund zu konstruieren. Um das Signal weiter zu separieren, wird eine Reihe von multivariaten Algorithmen verwendet und der ttH-Prozess wird unter Verwendung eines Profile-Likelihood-Fits extrahiert. Die Ergebnisse werden für den Kanal mit einem einzelnen Lepton im Endzustand und für eine Kombination mit dem Dilepton-Kanal gezeigt. Die Untergrundgenauigkeit wird im Detail untersucht, wobei große Fehlmodellierungen festgestellt werden. Das gemessene Verhältnis der ttH-Produktion zur Standardmodell-Vorhersage beträgt mu(ttH) = 0,84+0,45- 0,39 (syst.) +-0,21 (stat.). Das Ergebnis stimmt mit der Vorhersage des Standardmodells überein und entspricht einer beobachteten (erwarteten) Signifikanz von 1,9 sigma (2,3 sigma), eine Verbesserung gegenüber der vorherigen ATLAS-Messung, bei der eine Signifikanz von 1,4sigma (1,6 sigma) ermittelt wurden. / The discovery of the Higgs Boson in 2012 confirms the Standard Model as the most successful theory describing the fundamental interactions of elemental particles. One of the important properties of the Higgs boson is its Yukawa coupling to the top quark, which in the Standard Model is the strongest due to the high mass of the quark. This thesis reports on a measurement of the top-Yukawa coupling with data collected by the ATLAS detector from 2015 to 2018 at 13 TeV center of mass energy. The coupling is studied in ttH(bb) events, a final state containing decay products of two top quarks with additional emission of a Higgs boson, where the Higgs decays into a pair of bottom quarks. This decay channel of the Higgs Boson has the largest branching ratio, but is systematically limited by the description of the dominant background process ttbb, a tt with additional two b quarks in the final state. The measurement takes advantage of the ability of the ATLAS detector to identify jets coming from a b quarks to construct analysis regions with various compositions of the signal and the background. To further separate the signal, a series of multivariate algorithms is employed and the ttH process is then extracted using a profile likelihood fit. The results are shown for the channel with a single lepton in the final state and for a combination with the dilepton channel. The background performance is studied in detail, where large mis-modeling is found. The measured ratio of the ttH production compared to the Standard Model prediction is found to be mu(ttH) = 0.84 +0.45 -0.39 (syst.) +-0.21 (stat.). The result is in agreement with the Standard Model prediction and corresponds to an observed (expected) significance of 1.9 sigma (2.3 sigma), an improvement compared to the previous ATLAS measurement which reported 1.4 sigma (1.6 sigma).

M.Med. in Community Health, Faculty of Health Sciences, University of the Witwatersrand, 2011 / Introduction Three public health interventions well known to decrease the risks associated with pregnancy and child birth are access to maternity care, family planning and contraception, and safe abortion. Worldwide, the African region has the highest case fatality rate associated with unsafe abortion 750 per 100 000, largely as a result of restrictive abortion laws. South Africa (SA) legalised abortion in 1996 with the “Choice on Termination of Pregnancy” (CTOP) Act. It sought to improve the quality and access to termination of pregnancy (TOP) services in SA. Since its enactment there has been a 91% decrease in deaths due to unsafe abortions. There have been some experienced challenges associated with the implementation of the Act, limited number of functional TOP facilities, prolonged waiting times, and negative attitudes of TOP providers to clients. After more than a decade of liberalised law in SA, what are TOP providers’ perceptions, clients’ experiences and the overall quality of TOP services? Main Aim The evaluation of TOP services in the urban Johannesburg Metropolitan Municipality (JHB), Gauteng Province, and two rural municipalities Bela-Bela Municipality, Limpopo Province and Mangaung Municipality, Free State Province. Methodology A mixed methods approach was adopted; both quantitative and qualitative data were collected in three sections. Included were all primary health care facilities offering first trimester TOPs in the Johannesburg Metropolitan, Mangaung, and Bela-Bela Municipalities. Section I the analysis of district health information management system (DHIS) data for JHB. Section II, TOP providers and TOP clients completed self-administered questionnaires. Section III the TOP clients from JHB were questioned again after eighteen months. Various parametric and non-parametric tests were conducted on the data, based on the data distribution. The statistical software used for quantitative data analyses was Stata release 10.0 and qualitative data MAXQDA release 10.0. Results The DHIS showed a 61% increase in TOP requests from 2006 to 2009 (Chi-square for trend; P=0.08). The number of first trimester procedures performed only addressed 40% of total requests in 2006 and 33% of total requests in 2009. Section II demonstrated that all the TOP providers reported not coping with their duties, only two (15%) providers were comfortable with administering TOPs. One hundred and fifty-two TOP clients were recruited into the study. The mean age was 26.00 (±6.03) years. One hundred and sixteen (76%) women were not using contraception. Clients from JHB had prolonged waiting times 14 days (IQR; 6-28) compared to Bela-Bela clients’ 3 days (IQR; 1-6) (Post-hoc Wilcoxon- Ranksum; P<0.0001). Hence clients from JHB had TOPs at later median gestational ages of 9 weeks (IQR; 8-11) and Bela-Bela clients at 7.5 weeks (IQR;4-8) (Post-hoc Wilcoxon Ranksum; P<0.0001). Knowledge of the CTOP Act exceeded seventy percent across all three municipalities (Pearson Chi-square; P=0.83). Section III identified that 39% (n=9) of interviewed clients experienced a TOP-related complication. The odds of experiencing a complication was decreased if client received a follow-up appointment (OR 0.12; 95% CI 0.02-1.51; P=0.02), if client was aware of the CTOP Act (OR 0.11; 95% CI 0.01-2.08; P=0.06), and clients that had attended Lenasia South CHC had odds of complication 8 times higher than clients who had presented to Bophelong clinic (OR 8.68; 95% CI 3.47 -21.7; P<0.0001). The qualitative analysis identified themes of an association with intra-procedural pain and perceived inadequate counselling with those reporting emotional distress. Discussion The prevalence of contraceptive use during the month of conception was low, and the majority of clients were unaware of the correct gestational age for termination of pregnancy according to the CTOP Act. This suggests that the pre-TOP services required strengthening. The TOP services in the public sector may not to be addressing the number of TOP requests; this affects the availability of the service. TOP providers in different South African settings report similar challenges associated with delivering TOP services. The clients from JHB are waiting longer for the TOP and hence having the abortion at later gestational ages which are associated with increased complications rates. The study estimated a complication rate of approximately 26 per 100 abortion clients, higher than acceptable global rates which approximate 3 per 100. The improvement of pre and post-TOP counselling was highlighted. Conclusion This study introduces the importance of passive surveillance in improving the quality of service delivery. Though this is only achieved when data collected are analysed and used to inform policy and service. The studies conducted in South Africa since the CTOP Act enactment has demonstrated various challenges and areas for improvement. These findings have ensured that issues of public health importance continue to be studied and relevant findings disseminated to stakeholders for and consideration and action where appropriate.

Gonyostomum semen is a raphidophyte microalgae that can be found in brown water lakes all over Sweden. The species forms substantial summer blooms that can completely dominate the phytoplankton community, largely due to its limited grazing pressure. To test whether parasites control the abundance of G. semen, as well as to study a newly discovered predator – prey interaction, three experiments were set up. The first experiment aimed to look at potential parasite interactions by screening for infections in natural environments, but none could be found. The second experiment built on the first by testing if the lack of parasites was due to physiological characteristics of G. semen, by exposing the species to diatom parasites and observing the cell’s response. The third experiment investigated the impact of a predatory ciliate on G. semen cell abundance. This predator – prey interaction was first observed in fresh lake water samples and had so far not been described in the literature. First, G. semen alone was exposed to the ciliate, and later the prey preference of the ciliate was examined by offering it four different potential prey species. The results from the first and second experiment suggested that G. semen does not have any parasites, potentially due to lack of a supportive cell wall. When interacting with parasite zoospores, the G. semen cells burst open, meaning that a successful infection would not be possible. The third experiment showed that the ciliate does feed on G. semen, and that it likely prefers G. semen over other types of prey. The limited top – down control on G. semen gives the species an ecological advantage and is seemingly one of the main reasons for G. semen’s success in spreading to new habitats.

Environmental management and sustainability have been recent important issues in the hospitality industry. The hotel industry, as a main sector of the hospitality industry, has benefited from environmental initiatives through improving corporate image and increasing resource and energy efficiency. Among various environmental issues that have been addressed in the hotel industry, managerial influence on environmental management is rarely investigated. The purpose of this study was to examine the current state of environmental management in the hotel industry. Further, this study also determined a relationship between top managers' personal environmental attitudes and organizational involvement in environmental management practices. To achieve the purpose of this study, this study examined currently adopted green practices, top managers' environmental attitudes, and their perception of advantages derived from environmental management. Hotels that participated in this study showed greater involvement in energy management, water conservation, and waste management practices than hotels examined by previous research in different geographical areas. The results of this study showed a correlation between top managers' environmental attitudes and organizational involvement in environmental management. It was also found that top managers' environmental attitudes were positively related to their perceived advantages of environmental management. These findings present various managerial and theoretical implications for related organizations and hotel management companies. The hotel industry should keep promoting green hotel practices to reduce negative impacts on the valuable environment and increase operational efficiency. In order to promote environmental management in the hotel industry, related organizations, governments, and stakeholders need to focus on raising top managers' environmental awareness as well as providing information on successful cases of environmental management. / Master of Science

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