493,810 research outputs found

    A General Method for Model-Independent Measurements of Particle Spins, Couplings and Mixing Angles in Cascade Decays with Missing Energy at Hadron Colliders

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    We outline a general strategy for measuring spins, couplings and mixing angles in the case of a heavy partner decay chain terminating in an invisible particle. We consider the common example of a new scalar or fermion D decaying sequentially to other new particles C, B and A by emitting a quark jet j and two leptons ln and lf. We derive analytic formulas for the dilepton {ln,lf} and the two jet-lepton ({j,ln} and {j,lf}) invariant mass distributions for most general couplings and mixing angles of the new partners. We then consider various spin assignments for the particles A, B, C and D, and derive the relevant functional basis for the invariant mass distributions which contains the intrinsic spin information and does not depend on the couplings and mixing angles. We propose a new method for determining the spins of the new partners, using the three experimentally observable distributions {l+,l-}, {j,l+}+{j,l-} and {j,l+}-{j,l-}. We show that the former two only depend on a single model-dependent parameter alpha, while the latter may depend on two other parameters beta and gamma. By fitting these distributions to our set of basis functions, we are able to do a pure measurement of the spins per se. Our method is also applicable at a pp-bar collider such as the Tevatron, for which the previously proposed lepton charge asymmetry is identically zero and does not contain any spin information. In the process of determining the spins, we also obtain an independent measurement of the parameters alpha, beta and gamma, which represent certain combinations of the couplings and the mixing angles of the heavy partners A, B, C and D.Comment: 67 pages, 29 figures, typeset in JHEP styl

    Towards a Life Cycle Oriented Business Intelligence Success Model

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    Information System (IS) success has been an essential research issue in the IS community for nearly two generations of IS researchers. For the Business Intelligence (BI) domain we see the lack of a comprehensive, life cycle oriented success model. Based on an extensive review of BI success related literature, we propose a methodology for creating such success models in general and demonstrate the feasibility of the proposed approach within the context of BI. A life cycle oriented BI success model is presented including an outline of the constructs, their relationships, and associated measurement items. From a practical perspective, the results provide assistance for the future development of BI solutions in organizations. The paper deepens the understanding of success model adaptation and extension from a theoretical perspective

    Black Hole Images as Tests of General Relativity: Effects of Plasma Physics

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    The horizon-scale images of black holes obtained with the Event Horizon Telescope have provided new probes of their metrics and tests of General Relativity. The images are characterized by a bright, near circular ring from the gravitationally lensed emission from the hot plasma and a deep central depression cast by the black hole. The metric tests rely on fact that the bright ring closely traces the boundary of the black hole shadow with a small displacement that has been quantified using simulations. In this paper we develop a self-consistent covariant analytic model of the accretion flow that spans a broad range of plasma conditions and black-hole properties to explore the general validity of this result. We show that, for any physical model of the accretion flow, the ring always encompasses the outline of the shadow and is not displaced by it by more than half the ring width. This result is a consequence of conservation laws and basic thermodynamic considerations and does not depend on the microphysics of the plasma or the details of the numerical simulations. We also present a quantitative measurement of the bias between the bright ring and the shadow radius based on the analytical models.Comment: Submitted to Ap

    Factors affecting the purchasing of insurance over the internet.

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    by Elaine Bien McKay.Thesis (M.B.A.)--Chinese University of Hong Kong, 2000.Includes bibliographical references (leaves 36-38).ABSTRACT --- p.iiTABLE OF CONTENTS --- p.ivLIST OF ILLUSTRATIONS --- p.viLIST OF TABLES --- p.viiChapter CHAPTER I --- INTRODUCTION --- p.1Chapter 1.0 --- Overview --- p.1Chapter 1.1 --- Background --- p.1Chapter 1.2 --- Research Objective --- p.2Chapter 1.3 --- Conceptual Model --- p.3Chapter 1.4 --- Outline of the Paper --- p.3Chapter CHAPTER II --- A BACKGROUND OF THE INSURANCE INDUSTRYChapter 2.0 --- Overview --- p.4Chapter 2.1 --- Hong Kong - General Statistics --- p.4Chapter 2.2 --- Hong Kong Insurance Market --- p.5Chapter 2.3 --- The Online Insurance MarketChapter 2.3.1 --- Hong Kong Insurance Online --- p.6Chapter 2.3.2 --- United States Insurance Online --- p.7Chapter 2.4 --- Conceptual Framework --- p.9Chapter 2.4.1 --- Product Related Factors --- p.10Chapter 2.4.2 --- Internet Related Factors --- p.11Chapter 2.4.3 --- Personal Characteristics --- p.12Chapter 2.4.4 --- Attitudes and Intentions --- p.13Chapter CHAPTER III --- RESEARCH DESIGN AND METHODOLOGYChapter 3.0 --- Overview --- p.14Chapter 3.1 --- Data Collection --- p.14Chapter 3.2 --- Operationalization --- p.15Chapter 3.3 --- Data Analysis --- p.17Chapter CHAPTER IV --- ANALYSIS AND RESULTSChapter 4.0 --- Overview --- p.19Chapter 4.1 --- Measurement Model Evaluation --- p.19Chapter 4.2 --- Structural Model Results --- p.20Chapter CHAPTER V --- CONCLUSIONChapter 5.0 --- Overview --- p.23Chapter 5.1 --- Managerial Implications --- p.23Chapter 5.2 --- Limitations --- p.25APPENDIXBIBLIOGRAPH

    Group guided low intensity self-help for community dwelling older adults experiencing low mood : a dissertation presented in partial fulfillment of the requirements for the degree of Doctor of Clinical Psychology, Massey University, Albany, New Zealand

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    Depression is amongst the most common health issues affecting older adults, however, access to evidence-based psychological treatments remains low amongst this age group. This is due, in part, to numerous barriers that surround current mental health treatment and delivery, which has contributed to discrepancies between treatment needs, availability, and uptake. To address such barriers, low intensity Cognitive Behavioural Therapies (LI-CBT) and in particular guided self-help interventions have emerged as promising, brief, cost-effective, and evidence-based alternatives to traditional high intensity therapies. Recently, interventions have begun to utilise the advantages of guided LI-CBT selfhelp within a group or class setting, thus providing both a cost-effective and time-efficient form of treatment delivery. Of these group guided approaches, Living Life to the Full (LLTTF) is the only intervention that primarily targets depression and has undergone randomised effectiveness testing. While early evidence lends support for the efficacy of LLTTF, further research is needed to extend the findings to different populations and age groups, particularly older adults. The current study examined the effect of the group guided version of LLTTF on community dwelling older adults’ ratings of depression, anxiety, and quality of life. Additionally, the relationship between older adults’ engagement with LLTTF and improvements in their reported ratings on all primary outcome measures was evaluated. Twenty-four older adult participants with symptoms of depression were recruited from a New Zealand community setting. Participants completed the intervention over eight sessions and data was collected at baseline, during each session, and at 1- and 6-week follow-up. Data was analysed using Multilevel Modelling, implementing a multilevel (2 level), repeated measure (11 waves), single group design. Results indicated significant improvements in participants’ symptoms of depression, anxiety, and quality of life over time. There was no evidence of an interaction between participants’ engagement and depression or anxiety ratings. Unexpectedly, engagement did however interact with quality of life, demonstrating that higher levels of out-of-class engagement with self-help content was related to significantly lower improvements in quality of life. Finally, supplementary analyses indicated greater reductions in anxiety symptoms amongst participants who lived with others compared to those who lived alone. These results endorse LLTTF as a viable and effective low intensity treatment option for depression in older adults, with additional benefits for symptoms of anxiety and quality of life. When delivered to older adults, LLTTF could increase treatment access and choice, contribute to the reduction of secondary mental health service load, minimise treatment barriers, and importantly support older adults’ to manage symptoms of depression and anxiety while remaining in communities of their choosing

    The occurrences and potential mitigation of occupational fraud in the international non-governmental organisation (INGO) sector in Vietnam: an empirical holistic approach

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    Purpose – This research investigated the overall research question as follows: How do factors (individual-level, organisational-level, industry-level, and country-level) influence occupational fraud in the INGO sector in Vietnam? This thesis addresses occupational fraud or internal fraud, rather than external fraud, because the former accounted for the majority of losses due to fraud. Additionally, this thesis has two foci: what may contribute to fraud – the second focus, and what may prevent fraud – the first focus. Specifically, the first focus is on how effective organisational-level factors are at preventing or reducing fraud (undetected, suspected, actual/detected, and future). Whilst, the second focus is on factors (individual-level, organisational-level, industry-level, and country-level) that may contribute to fraud (future only). Design/methodology/approach – This study develops a conceptual model, built on the fraud triangle by Cressey in 1950. The model combines: fraud (undetected, suspected, actual/detected, and future); individual-level determinants (e.g. pressures); organisational-level determinants [e.g. organisational ethical culture (OEC), organisational ethics program (OEP), and organisational internal control (OIC)]; the industry-level determinant (e.g. the non-profit nature); and country-level determinants (e.g. cultural, political, legal, economic, and technological). The methodological choice of research design is quantitative, using the survey strategy with a self-administered questionnaire to collect data. The questionnaires were administered to the entire target population of 408 INGOs (a census) in Vietnam. In each INGO, only one potential survey respondent was approached. Potential respondents were high-level staff members such as Chief Executive Officers (CEOs), Chief Financial Officers (CFOs), Chief Accountants (CAs), accounting/auditing/financial employees, and other managers (e.g. human resources managers). In order to approach potential respondents, the current research used two survey modes: the paper-based (drop-off) mode (administered through Indochina, a research company) and the web-based (online) mode (administered through the Internet). Furthermore, descriptive and inferential data analysis was performed. In inferential analysis, testing the goodness of the data, including the scales used, was undertaken, prior to hypotheses testing. Chi-square test for independence, independent-samples t-test, exploratory factor analysis (EFA), confirmatory factor analysis (CFA), multivariate analysis of variance (MANOVA), logistic regression, and multiple regression were statistical techniques employed in inferential analysis. CFA was executed by AMOS, whilst the rest were performed by SPSS. Results – This thesis attained 177 usable returned questionnaires, representing the overall response rate to be 47.6%. The results of statistical analyses are as follows. What may prevent fraud? – The first focus. Actual fraud At the model level, the combination of OEC, the effectiveness of OEP, and the effectiveness of OIC, to some extent, significantly predicted actual fraud. Likewise, the combination of the degree of OEP and the degree of OIC, to some extent, significantly predicted actual fraud. Moreover, at the independent variable level, the dimension of supportability under OEC as well as both the degree and effectiveness of OIC make unique statistically significant contributions to predicting/explaining actual fraud. Specifically, the latter is related to the effectiveness of the three dimensions under OIC. They are: management-performed monitoring activities and process-level control activities; commitment-to-competence control environment; and audits-performed monitoring activities and gifts-hospitality control activities. In which, commitment-to-competence control environment made the strongest unique contribution to predicting actual fraud. Conversely, the degree and effectiveness of OEP play no role in mitigating actual fraud. Undetected fraud At the model level, the combination of OEC, the effectiveness of OEP, and the effectiveness of OIC, to some extent, significantly predicted undetected fraud, whilst the combination of the degree of OEP, and the degree of OIC did not. In addition, at the independent variable level, only the dimension of supportability under OEC made a unique statistically significant contribution to predicting undetected fraud, but not the effectiveness and degree of OEP and OIC. Suspected fraud At the model level, the combination of OEC, the effectiveness of OEP, and the effectiveness of OIC, to some extent, significantly predicted suspected fraud, whilst the combination of the degree of OEP, and the degree of OIC did not. Additionally, at the independent variable level, there were three dimensions making unique statistically significant contributions to predicting suspected fraud. They were: the dimension of discussability under OEC, the effectiveness of the dimension of ethics-incorporated performance and employment under OEP, and the effectiveness of the dimension of monitoring activities and process-level control activities under OIC. In which, ethics-incorporated performance and employment made the strongest unique contribution to predicting suspected fraud. Conversely, the degree of OEP and OIC played no role in mitigating suspected fraud. Future fraud At the model level, the combination of OEC, the effectiveness of OEP, and the effectiveness of OIC, to some extent, significantly predicted future fraud, whilst the combination of the degree of OEP, and the degree of OIC did not. Moreover, at the independent variable level, only the dimension of supportability under OEC made a unique statistically significant contribution to predicting future fraud, but not the effectiveness and degree of OEP and OIC. What may contribute to fraud (future only)? – The second focus. For the purposes of this thesis, individual-level determinants (e.g. pressures), organisational-level determinants (e.g. poor OEC, poor OIC), and the industry-level determinant (e.g. the non-profit nature) are micro factors, whilst country-level determinants (e.g. cultural, political, legal, economic, technological) are macro factors. At the model level, the combination of the determinants, to some extent, significantly contributed to engendering future fraud. In addition, at the independent variable level, there were five factors making unique statistically significant contributions to engendering future fraud. They are: two individual-level factors: non-financial personal pressure (e.g. lack of personal discipline, greed) and financial corporate/employment pressure (e.g. management financial interest, low salary); one organisational-level factor: poor OIC; one industry-level factor: the non-profit nature in the operation of INGOs; and one country-level factor: the legal factor in Vietnam. In which, the non-profit nature was the strongest source of future fraud, whilst poor OIC is considered to be a silent source of future fraud. Originality/value – This thesis has made three distinct contributions to the literature. Firstly, it is the first comprehensive study worldwide to incorporate individual-level, organisational-level, industry-level, and country-level factors into predicting future fraud in the INGO/NPO (non-profit organisation) sector in a specific country (e.g. Vietnam), with statistically empirical evidence. Secondly, it is the first comprehensive study worldwide to examine different stages of fraud occurrence (undetected, suspected, actual/detected, and future), with statistically empirical evidence. Thirdly, it is the first comprehensive study in Vietnam as well as in developing countries to investigate fraud in the INGO/NPO sector (industry-level), with statistically empirical evidence. Besides, this thesis also provided other remarkable theoretical contributions. Practical implications – The results of this thesis are useful for different stakeholders in the INGO sector in Vietnam. The results may also be beneficial to stakeholders in the INGO/NPO sectors in other developing countries, which have similar or close national context factors as in Vietnam. The groups of stakeholders include: (1) CEOs, CFOs, CAs and other directors/managers of INGOs; (2) donors of INGOs; (3) auditors related to INGOs; and (4) the Vietnamese government. Furthermore, fruitful areas of further research were identified, in which five research areas, being equivalent to five research projects, could use the data collected by this thesis

    Statistical models for animal telemetry data with applications to harbor seals in the Gulf of Alaska

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    2017 Spring.Includes bibliographical references.Much is known about the general biology and natural history of harbor seals (Phoca vitulina), but questions remain about the aquatic and terrestrial space use of these marine mammals. This is in large part because methods for examining the spatial ecology of harbor seals are poorly developed. The objective of this dissertation is to pair existing telemetry data with contemporary spatio-temporal modeling to quantify the space use and resource selection of harbor seals in the coastal waters of southern Alaska. Recent extensions to models for analyzing animal telemetry data address complications such as autocorrelation and telemetry measurement error; however, additional challenges remain, especially in the context of analyzing Argos satellite telemetry data collected on marine mammals like harbor seals. For example, existing methods assume elliptical (or circular) patterns of measurement error, even though Argos satellite telemetry devices impose more complicated error structures on the data. Constraints, or barriers, to animal movement present another complication. Harbor seals and other marine mammals are constrained to move within the marine environment, and mechanistic models that do not adhere to movement barriers yield unreliable inference. Therefore, a primary goal of this research is to develop statistical tools that account for these nuances and provide rigorous, ecologically relevant inference. Even though the models presented in this dissertation were specifically developed with Argos satellite telemetry data and harbor seals in mind, the methods are general and can be applied to other species and types of telemetry data. This dissertation consists of five chapters. In Chapter 1, I briefly discuss the general biology of harbor seals, focusing on what is known about their spatial habits in Alaska. I then summarize trends in Alaskan harbor seal abundance, a topic that motivated my research as well as the work of many others. I describe the existing Alaska Department of Fish and Game telemetry data sets that are available for examining harbor seal spatial ecology, commonly-used statistical methods for analyzing animal telemetry data, and conclude with the objectives of my research and an outline for the remainder of the dissertation. In Chapter 2, I propose an approach for obtaining resource selection inference from animal location data that accounts for complicated error structures, movement constraints, and temporally autocorrelated observations. The model consists of two general components: a model for the true, but unobserved, animal locations that reflects prior knowledge about constraints to animal movement, and a model for the observed telemetry locations that is conditional on the true locations. I apply the model to simulated data, showing that it outperforms common ad hoc approaches used when confronted with telemetry measurement error and movement constraints. I then apply the framework to obtain inference concerning aquatic resource selection and space use for harbor seals near Kodiak Island, Alaska. Chapters 3 and 4 shift the focus from inference concerning aquatic space use and resource selection, to inference concerning the use of coastal resources (i.e., haul-out sites) by harbor seals. In Chapter 3, I present a fully model-based approach for estimating the location of central places (e.g., haul-out sites, dens, nests, etc.) from telemetry data that accounts for multiple sources of uncertainty and uses all of the available locational data. The model consists of an observation model to account for large telemetry measurement error and animal movement, and a highly flexible mixture model (a Dirichlet process) to identify the location of central places. Ancillary behavioral data (e.g., harbor seal dive data obtained from the satellite-linked depth recorders) are also incorporated into the modeling framework to obtain inference concerning temporal patterns in central place use. Based on the methods developed in Chapter 3, I present a comprehensive analysis of the spatio-temporal patterns of haul-out use for harbor seals near Kodiak Island in Chapter 4. Chapter 4 also extends previously developed methods to examine the affect of covariates on haul-out site selection and to obtain population-level inference concerning haul-out use. I conclude, in Chapter 5, with some general thoughts about analyzing animal telemetry data, as well as potential future research directions

    Sustainability and transparency in computational cognitive neuroscience

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    In this talk, I will discuss open science practices that aim to foster sustainability and transparency in computational cognitive neuroscience. First, I will review recent community efforts that aim to ease data sharing and analytical reproducibility, such as the reports of the OHBM Committees on Best Practice in Data Analysis and Sharing (COBIDAS) and the Brain Imaging Data Structures (BIDS). Second, I will discuss neuroimaging data sharing strategies in the light of ethical and legal constraints, such as the European General Data Protection Regulation (GDPR). Finally, I will discuss some common-sense guidelines for day-to-day research practice that aim to maximize the societal impact of computational cognitive neuroscience

    Preservice elementary school teachers' knowledge of fractions: a mirror of students' knowledge?

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    This research analyses preservice teachers' knowledge of fractions. Fractions are notoriously difficult for students to learn and for teachers to teach. Previous studies suggest that student learning of fractions may be limited by teacher understanding of fractions. If so, teacher education has a key role in solving the problem. We first reviewed literature regarding students' knowledge of fractions. We did so because assessments of required content knowledge for teaching require review of the students' understanding to determine the mathematics difficulties encountered by students. The preservice teachers were tested on their conceptual and procedural knowledge of fractions, and on their ability in explaining the rationale for a procedure or the conceptual meaning. The results revealed that preservice teachers' knowledge of fractions indeed is limited and that last-year preservice teachers did not perform better than first-year preservice teachers. This research is situated within the broader domain of mathematical knowledge for teaching and suggests ways to improve instruction and student learning
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