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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
351

Extreme AGN feedback in highly-luminous clusters of galaxies

Hlavacek-Larrondo, Julie January 2012 (has links)
No description available.
352

Production of reactive oxygen species in mitochondria and mitochondrial DNA damage

Logan, Angela January 2011 (has links)
No description available.
353

The Relation between Luminous Active Nuclei and Star Formation in Their Host Galaxies

Xu, Lei January 2013 (has links)
Studies of central black holes (BHs) in nearby galaxies revealed tight correlation between the BH mass the host galaxy bulge mass, indicating a link between BH and star formation (SF) in the host galaxy. Luminous active galactic nuclei (AGN) are powered by mass accretion onto supermassive BHs. Observations of the AGNs and the SF in their host galaxies are required to understand their relation and how they establish this BH mass-galaxy bulge mass correlation over a wide range of cosmic lookback times. This thesis presents a survey of 24 μm-selected luminous AGN and their host galaxies up to z ~ 3.2. It focuses on the foreground and background broad line (Type-1) and narrow line (Type-2) AGNs of 30 massive galaxy cluster fields with total survey area of 5.2 deg², using the multi-wavelength dataset from the ultraviolet (UV) to far infrared (FIR) from the Local Cluster Substructure Survey. The AGN sample is nearly complete to a 1 mJy flux cutoff at 24 μm, and is optical-spectroscopically identified. With this dataset and the accompanying MMT/Hectospec spectroscopy survey, the properties of AGNs such as BH masses, BH accretion rates, and total luminosities, can be readily determined. Particularly, the Herschel data (100, 160, 250, 350, and 500 μm) sample the FIR peak of sources in our sample, and provide constraints on the star formation rates (SFR) in the host galaxies. For the Type 1 AGN sample, most of the systems are at z > 0.6 with luminosities > 10^45 ergs/s. Out of the 205 Type-1 AGNs, 107 are detected in at least two Herschel bands. We use AGN, stellar, and SF galaxy templates to decompose their spectral energy distributions (SEDs) from the UV to the FIR, and estimate their IR SF luminosities, AGN luminosities, and their host galaxy stellar masses. The SED decomposition reveals that a high level of SF is ubiquitous for our 24 μm-selected Type-1 AGN sample. For sources at z < 1, the stellar components from SED decomposition provide direct constraints on the stellar mass. For sources at z > 1, the BH mass-bulge stellar mass correlation is used for indirect constraints on the stellar mass. We carried out a similar analysis on the 85 Type-2 AGNs and their host galaxies up to z ~ 0.8, out of which 55 are detected in at least two Herschel bands. We reach the same conclusion as for the Type 1 AGN sample. That is, 1) These AGN host galaxies are very massive, and the vast majority of these galaxies have specific star formation rates (SSFR) consistent with those of main-sequence, star-forming galaxies rather than starbursting galaxies; 2) Most of these AGNs accrete at a rate close to 10% of Eddington; 3) We also find a strong correlation between the IR luminosity of the SF component and the AGN total luminosity, for both Type 1 and Type 2 AGNs. However, we show that the correlation could arise just because the BH mass (and hence AGN total luminosity) and the SF are both correlated with the galaxy mass, rather than requiring a causal connection between the observed rates of SF and the nuclear activity.
354

Studies of particle interactions in latexes

Homola, Andrew M. January 1974 (has links)
No description available.
355

Semi-supervised and active training of conditional random fields for activity recognition

Mahdaviani, Maryam 05 1900 (has links)
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.
356

Application of active inductors in high-speed I/O circuits

Lee, Yen-Sung Michael 11 1900 (has links)
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.
357

Politics of End-of-Life Care: Active Euthanasia

Coombes, Kendra 22 March 2013 (has links)
With new medical advances in technology, there has been a push from the legal, medical and political communities to re-examine the policies of end-of-life-care. End-of-life-care (EOLC) is a term that refers to not only a patient’s final hours of life, but also the medical care of individuals with terminal illnesses or conditions that have become advanced and incurable. For the purpose of this paper, I will be referring to physician-assisted death and active euthanasia as forms of end-of-care. The Politics of End-of –Life-Care: Active Euthanasia and Physician-assisted Death examines the political disjuncture between the evidence presented in favour of active euthanasia (AE), physician-assisted death (PAD) and the current practice of refusing to grant AE and PAD legal status in Canada. It will examine the political dynamics underlying the disjuncture using political pressure groups, constructivism, rational choice, institutionalism and structuralism. There is empirical evidence that demonstrates support for the legalization of AE and PAD. Sixty-seven percent of Canadians support AE /PAD and 80 percent support allowing physicians to assist in AE and PAD (Angus Reid 2012) however, Parliament has not legalized AE/PAD and the CMA has not sanctioned AE /PAD. The two sides of the debate have clearly communicated their arguments. The arguments on each side are strong and have merit. Conversely, the arguments against AE and PAD appear to hold more weight with institutions than with the public. This thesis examines a number of different reasons for why AE/PAD remains illegal in Canada despite society’s widespread support for AE/PAD. The results of the research found no one method explains the disjuncture between the evidence presented in favour of active euthanasia and the current practice of refusing to grant it legal status. However, discursive institutionalism does help elites to generate and communicate the discourse of AE and PAD. It also explains how discourse can also occur from the bottom which results in a new discourse. For example, physicians, politicians, and the public who have deviated from the accepted discourse on AE and PAD can help to create a new discourse regarding AE and PAD policies.
358

Education as a Political Act: Dewey, Freire and the (International Baccalaureate) Theory of Knowledge Curriculum

DARWISH, BABOR 11 August 2009 (has links)
Active learning should be the ultimate aim of education. I argue that it is a three interrelated-step model of curriculum: one which promotes critical thinking, involves dialogue and ultimately indicates growth. It is a model intertwined in an intricate web of ideas borrowed from John Dewey and Paulo Freire. In this thesis, I analyze the International Baccalaureate (IB) Theory of Knowledge (TOK) curriculum as an example of a document that seeks to foster active learning. To be able to analyze whether the IB TOK curriculum promotes active learning, I dissect the curriculum in terms of its philosophy and objectives. Curriculum theorists do not agree on a universal definition of curriculum. Therefore, I explore four distinctive theories of curriculum and theory in order to find a definition that best fits the IB TOK curriculum and philosophy: 1) curriculum as a body of knowledge to be deposited, 2) curriculum as a product theory, 3) curriculum as a process, and 4) curriculum as praxis. I argue that in order for active learning to take place, the three components of active learning need to exist together. Active learning needs to promote critical thinking as a means to understanding one’s self and others. And, active learning needs to involve dialogue to enable people to become fully aware of their own position within the community and the world, and that of others. Critical thinking and dialogue in turn ensure growth. Growth is defined in terms of conscientização and Praxis; this is premised on two conditions: 1) to become aware of the realities in one’s life; and, 2) to take informed and practical actions to change these assumptions. It is then, I argue, that learning becomes active. It is indeed, as Freire would say, breaking away from ‘silence’ imposed on us by oppressors and attaining “the freedom of the learner” in Dewey’s words. It is only through active learning that individuals can critically think, enter a meaningful dialogue with others, and ultimately have the courage to act, and as a result create a life which is meaningful—not just for themselves but for everyone. / Thesis (Master, Education) -- Queen's University, 2009-08-07 17:56:13.739
359

ACTIVE TRANSPORTATION TO SCHOOL AMONG CANADIAN YOUTH: AN EXPLORATION OF CORRELATES AND ASSOCIATED INJURY

Gropp, Kathleen Mary 13 August 2012 (has links)
Background: Active transportation refers to methods of travel that involve physical activity, such as walking and bicycling. For students, characteristics of both individual and contextual environments are likely associated with active transportation to school. Furthermore, injury is one possible but overlooked outcome of active transportation to school. Objectives: To examine among urban Canadian youth in grades 6-10: 1) associations between individual- and area-level factors and active transportation to school and 2) the relationship between active transportation to school and active transportation injury. Methods: Individual-level data were obtained from the 2009/2010 Canadian Health Behaviour in School-Aged Children (HBSC) survey. Active transportation to school was measured via student’s report of their usual method of travel to school. Active transportation injury was assessed via self-report for a one-year recall period. Area-level data were obtained from a school administrators’ survey and from various geographical sources. Multi-level logistic regression was used to examine the associations of interest. Results: Multiple correlates of active transportation to school were identified from the individual/family, school, and neighbourhood. Correlates possessing a potential for intervention and a relatively high population impact were identified: gender (female: relative risk, RR=0.86, 95% CI: 0.80-0.91, population attributable risk, PAR: 7.1%), perception of neighbourhood safety (disagree vs. strongly agree: RR=0.83, 95% CI: 0.70-0.95, PAR: 2.3%), percentage of roads with sidewalks (quartile 3 vs. quartile 1: RR=1.17, 95% CI: 0.96-1.34, PAR: 9.5%), and the total length of streets (quartile 4 vs. quartile 1: RR=1.23, 95% CI: 1.00-1.42, PAR: 6.9%). A positive association between active transportation to school and active transportation injury was identified; the risk for injury increased as walking or bicycling increased (short distance: OR=1.17, 95% CI: 0.92-1.50; long distance: OR=1.56, 95% CI: 1.10-2.21). Conclusions: Many factors are associated with active transportation to school. While active transportation is associated with the potential for improved health, it also likely increases the risk for active transportation injuries. Interventions to increase active transportation to school should also consider potential negative outcomes. Future studies in this research area could focus on qualitative measures of the environment and school programs, in addition to the etiology of injuries experienced during school travel. / Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2012-08-12 15:11:48.409
360

NOVEL MACHINE LEARNING ALGORITHMS

Farhangfar, Alireza Unknown Date
No description available.

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