title: The surface brightness distribution of Virgo cluster galaxies

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subject: Astronomy Astrophysics Extragalactic

abstract: Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2007-08-10 10:04:56.651

abstract: We have acquired near-IR H and optical $g$,$r$,$i$,$z$ imaging for a sample of 299 Virgo cluster galaxies down to a limiting magnitude of B$_T$=16.0 mag. The low sensitivity of near-IR wavelengths to dust extinction is crucial for an unbiased geometric deprojection of fundamental galaxy parameters. We find, in agreement with Tully and Verheijen (1997), a clear dichotomy between high and low surface brightness galaxy disks. The difference between the low and high brightness peaks of Virgo galaxies is $\sim$2 H-mag arcsec$^{-2}$, significantly larger than any systematic errors. The high surface brightness galaxies have two distinct classes of bulge with high and low concentration, while low surface brightness galaxies have only low concentration bulges. The distribution of the effective surface brightnesses of our entire sample shows that early-type galaxies exhibit a similar structural bimodality though offset from that of spiral galaxies towards higher surface brightnesses. We find that the structural bimodality is uncorrelated with colour or any other structural parameter except, perhaps, the circular velocity. Simulations of realistic surface brightness profiles show that a bimodality in effective surface brightness is unexpected based on normal distributions of fundamental bulge and disk parameters. Rather, the structural bimodality is likely linked to the galaxy dynamics, namely the specific angular momentum of the galaxy; high surface brightness galaxies have low angular momentum and can collapse to form dynamically important disks, while low surface brightness galaxies are dominated by the dark halo everywhere. Finally, our bulge-disk decompositions of all the sample galaxy images using various fitting functions have revealed that galaxies of all morphologies, including flattened and spheroidal systems, exhibit a ``disk'' component which is best described by a generalized ``Sersic'' function. We also find that the majority of galaxy disks show significant deviations from a pure exponential. Further dynamical studies of both cluster and field galaxies are needed to properly explain the observed structural bimodality in both early- and late-type galaxies.

abstract: M.Sc.


title: Value gain from corporate reorganization

contributor:
Davis, Alfred
Management

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rights: This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.

subject:
Divestitures
Income trusts
Tax-free spin-offs
Carve-outs
Corporate finance
Volatility
Bootstrap

abstract: Thesis (Ph.D, Management) -- Queen's University, 2007-08-15 11:20:20.465

abstract: In the absence of taxes and transactions costs, there can be no benefit to corporate reorganization from a financial standpoint, but ‘real world’ limitations and frictions do provide additional value that is gained through divestitures in terms of focus and financial flexibility.  Herein, the corporate divestiture decision is analyzed to determine the motivation for a parent company either to cleave its offspring directly to the external capital market in an equity carve-out or to distribute the shares to the existing shareholders in a tax-free spin-off.  Cash flow performance, asymmetric information, relative size of the divestiture, and relatedness of the parent’s and subsidiary’s operations are all found to contribute significantly to the divestiture decision.  In Canada, an alternate form of security, known as the income trust unit, has become popular for corporate reorganizations, either through an initial public offering or as a conversion of shares.  The flow-through structure of income trusts currently allows avoidance of corporate taxation to offer higher pre-tax returns to retail investors, in a market setting where yield is increasingly equated with value.  To determine placement of these securities in the market, the risk of the income trust organizational form is analyzed and compared to the standard corporate form.  Further, a number of publicly known characteristics of the income trusts can predict the relative risk of this type of investment.  In recent ‘hot markets’ for these securities, proof is uncovered that unsuitable firms have been migrating to this sector, but valuation of the investments in this sector has remained fair and full.  Although pending legislation will discontinue the tax-exempt status of income trusts in 2011, during their tenure these securities have improved the Canadian market.  Based on the data analysis herein, all types of divestitures studied have been predicted to provide commensurate value with respect to risk depending on the nature of the subsidiary.

abstract: PhD


title: Infrared Observations of the Spiral Galaxy NGC 891

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subject:
Astronomy
Galaxy
NGC 891
PAHs

abstract: Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2007-08-15 22:39:02.167

abstract:
This thesis is a detailed, multi-waveband study of the inner 14 kpc of the famous spiral galaxy, NCG 891. The primary data have come from the Infrared Space Observatory's Camera. These data are images of the galaxy in 9 different mid-infrared wavebands. We have supported these data with archived data from the Spitzer Infrared Array Camera in 4 similar wavebands. Surface brightness contour maps of the galaxy were created and examined
to determine where the mid-infrared emitters are located with respect to the galactic plane. We have determined that the main mid-infrared emission, due to warm dust and PAHs, lies in a thin disk of width 700 - 800 pc, but has faint emission that reaches up to about 2.3 kpc into the halo.

The infrared spectral energy distribution (SED) for four environments in NGC 891 were created from the above mentioned wavebands as well as measurements from Spitzer's Multiband Imaging Photometer (3 Far-Infrared wavebands), the Two Micron All Sky Survey J, H, and K near-infrared wavebands, and the Sub-millimeter Common User Bolometer Array 450 and 850 $\mu$m bands. These spectra were fit with a SED model created by Frederic Galliano, and the physical properties of these environments were computed. The maps and SED show that while there is a relatively large amount of dust in NGC 891's halo, there is a depletion of PAHs beyond 2.3 kpc from the mid-plane. This is only the fourth galaxy to date that has PAH emission discovered in the halo, and it is the first in which the SED has been modeled for the halo.

abstract: M.Sc.


title: Delay-based packet scheduling for High Speed Downlink Packet Access

contributor:
Hassanein, Hossam S.
Nasser, Nidal
Computing

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subject:
HSDPA
Multimedia applications
QoS
Max CIR

abstract: Thesis (Master, Computing) -- Queen's University, 2007-08-15 16:12:36.22

abstract:
High Speed Downlink Packet Access (HSDPA) is a cellular system that was standardized by the 3rd Generation Partnership Project (3GPP). HSDPA can support data rates of up to 14.4 Mbps through the use of a shared channel. Due to its high transmission rates, the highly popular multimedia applications are converging over this network. Moreover, as the shared channel is assigned to a single user in a given time interval, the scheduling decision is considered as a crucial one. Conventional HSDPA scheduling schemes utilize the fluctuations in channel condition to maximize system throughput by selecting users with relatively good radio conditions. However, this raises the issue of fairness as users with relatively poor channel conditions might not be served and consequently may suffer from starvation. Furthermore, Real-Time (RT) applications have strict delay constraints and require that packets are transmitted within a certain delay threshold.

In this thesis, a Delay Based Scheduler (DBS) is proposed for HSDPA which aims at minimizing the average queuing delay at the packet scheduler without compromising system throughput and fairness. In addition, the scheme can balance the tradeoff between throughput maximization and the minimization of queuing delay through the attunement of a parameter, thus allowing the service provider to choose between these two metrics. The DBS maintains the delay constraints of RT applications by defining delay thresholds for each traffic class and dropping packets that exceed their delay limit. The DBS accommodates Quality of Service (QoS) prioritization by defining and utilizing desired QoS parameters in the scheduling assignment. Finally, it was mathematically shown that the DBS can converge to a Non-Real-Time (NRT) scheme known as the Max CIR algorithm, allowing the scheduler to support RT and NRT applications simultaneously. The performance of the DBS was evaluated and compared to other well known schemes. It was found that the DBS can minimize the aggregate queuing delay of the system and maintain similar throughput and fairness.

abstract: M.Sc.


title: Novel Digital Controller for Multi Full-Bridge DC/DC Converter

contributor:
Jain, Praveen K.
Electrical and Computer Engineering

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subject:
Power Electronics
Electrical Engineering
Fuel Cells
Digital Control
DC/DC Converter
Field Programmable Gate Array (FPGA)
Multi Full-Bridge

abstract: Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2007-09-25 10:26:39.909

abstract:
Distributed generation that utilizes 5-10kW Solid Oxide Fuel Cells requires power electronics to optimize the overall system efficiency while reducing the cost.  The Adaptive Energy Zero-Voltage-Switching Phase-Shift-Modulated Full-Bridge (AE-ZVS-PSM-FB) topology meets these criteria under all loading conditions, but suffers from complexity associated with an analog control implementation.  This thesis presents a novel Look-Up-Table (LUT) based digital controller required for such converter.  The applied design approach also reduces the design time and controller requirements, which in turn decreases the overall system cost.
Steady-state analysis for the AE-ZVS-PSM-FB converter is performed using a piece-wise equivalent circuit model.  This analysis is used to verify the LUT concept that forms the basis for the proposed LUT-based digital controller.  The proposed LUT-based digital control algorithm is developed and verified using Field Programmable Gate Array (FPGA) Logic platform.  Design procedures and operational function under steady state and step change conditions are presented.
Simulation results demonstrate the LUT concept in the AE-ZVS-PSM-FB converter, and the simplicity of the proposed LUT-based digital controller in producing the expected switching sequence.  Simulation results were also produced showing successful dynamic response of LUT-based digital controller interconnected with the converter under different operating conditions.  A Xilinx FPGA demonstration board was used to generate experimental switching sequence results to demonstrate the simplicity of the proposed controller.

abstract: M.Sc.


title: Analysis and improvement of performance and power consumption of chip multi-threading SMP architectures

contributor:
Afsahi, Ahmad
Electrical and Computer Engineering

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subject:
Computer engineering
Computer architecture

abstract: Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2007-08-16 16:06:15.414

abstract:
Emerging processor technologies are becoming commercially available that make multi-processor capabilities affordable for use in a large number of computer systems.  Increasing power consumption by this next generation of processors is a growing concern as the cost of operating such systems continues to increase.
It is important to understand the characteristics of these emerging technologies in order to enhance their performance.  By understanding the characteristics of high performance computing workloads on real systems, the overall efficiency with which such workloads are executed can be increased.  In addition, it is important to determine the best trade-off between system performance and power consumption using the variety of system configurations that are possible with these new technologies.
This thesis seeks to provide a comprehensive presentation of the performance characteristics of several real commercially available simultaneous-multithreading multi-processor architectures and provide recommendations to improve overall system performance.  As well, it will provide solutions to reduce the power consumption of such systems while minimizing the performance impact of these techniques on the system.
The results of the research conducted show that the new scheduler proposed in this thesis is capable of providing significant increases in efficiency for traditional and emerging multi-processor technologies.  These findings are confirmed using real system performance and power measurements.

abstract: M.Sc.


title: Stimulus-response specificity of human conduit artery flow mediated dilation

contributor:
Tschakovsky, Michael E.
Kinesiology and Health Studies

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subject:
Endothelial function
Flow mediated dilation

abstract: Thesis (Ph.D, Kinesiology & Health Studies) -- Queen's University, 2007-08-16 18:11:18.941

abstract: An increase in blood flow associated shear stress results in an endothelial dependent increase in vessel diameter (flow mediated vasodilation (FMD)).  Assessment of FMD can provide an index of endothelial function. The stimulus profiles that have been used to investigate FMD in human conduit arteries fall into two categories:  reactive hyperemia and sustained stimuli. Stimulus-response specificity proposes that the stimulus characteristics (e.g. magnitude, pattern) are essential determinants of the response characteristics (e.g. magnitude, mechanisms).  Purpose: To investigate four specific aspects of FMD stimulus-response specificity: 1) The relative importance of the peak vs. the duration of reactive hyperemia in determining FMD response magnitude. 2) The nitric oxide (NO) dependence of FMD following different durations of reactive hyperemia.  3) The impact of sustained shear stress stimulus magnitude on FMD response dynamics and magnitude.  4) FMD dynamics and magnitude in response to steady vs. oscillatory shear stress evoked passively or via exercise.  Methods:  Doppler ultrasound was applied to the brachial or radial artery to measure blood flow velocity.  Vessel diameter was measured with automated edge detection software.  Shear rate, an estimate of shear stress was calculated as the blood flow velocity/vessel diameter.  Results: 1) The duration of reactive hyperemia is an important determinant of peak FMD magnitude while the independent contribution of the peak shear to FMD is minimal.  2) NO is not obligatory to FMD following either a five or a ten minute duration occlusion.  3) FMD in response to a sustained stimulus is characterized by a generally bi-phasic response with a fast first phase followed by a slower final phase.  4) The endothelium transduces the mean shear stress when it is exposed passive or handgrip exercise induced oscillations in shear stress.  Conclusions:  The results indicate that future reactive hyperemia studies must account for the stimulus duration when interpreting FMD results.  Further, they demonstrate that the role of NO in FMD is unclear and caution against oversimplified conceptual models of FMD mechanisms.  FMD in response to sustained stimuli provides information distinct from reactive hyperemia investigations and exercise may provide a valuable stimulus creation technique.

abstract: PhD


title: Venetian Art and the War of the League of Cambrai (1509-17)

contributor:
McTavish, David
Art History

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subject:
Venice
Art
Cambrai War

abstract: Thesis (Ph.D, Art History) -- Queen's University, 2007-09-21 11:57:46.12

abstract: This dissertation explores how Venetians used the figurative arts as a means of responding to and shaping their experience of the War of the League of Cambrai (1509–17). The war was the most politically and spiritually tumultuous conflict in Venice’s history and almost resulted in the loss of its mainland empire. To provide a sense of the complexity of the relationship between art and contemporary military events, the study gathers and analyses a wide range of works, from painting and sculpture to woodcuts for books and prints. Chapters two, three, and four investigate how Venetians used visual art to represent and interpret their struggle to reclaim the former terraferma empire. Chapter two begins the discussion by examining the modest woodcuts accompanying printed propagandistic texts that were inspired by the battle for the mainland and that constitute the first visual response to the war. Chapter three explores the interpretation afforded military events by subsequent and more enduring works of art, particularly sculpted altarpieces and tombs for mercenaries. Chapter four discusses the assertive revival of more traditional visual themes, particularly the lion of St. Mark. Chapters five, six, and seven, in contrast, address how Venetian art reflects the atmosphere of spiritual crisis generated by the popular interpretation of the war as a form of divine punishment. The first of these demonstrates how devotional books responded to the unsettled mood through text and image. Chapter six proposes that the wartime popularity of multi-block woodcuts, particularly of religious subjects, similarly reflects a market for certain kinds of devotional imagery. To conclude, chapter seven argues that the same atmosphere sparked a sudden interest during the war and shortly thereafter in paintings of Christ and the adulteress. Considered as a group, the studies presented by the various chapters demonstrate that Venetians produced a wide variety of art during the Cambrai War as a means of interpreting the conflict’s significance and influencing its course.

abstract: PhD


title: Cloning and Functional Characterization of the Retinoic Acid-Catabolizing Enzyme CYP26B1 in Mouse Development

contributor:
Petkovich, Martin
Pathology and Molecular Medicine

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subject:
Retinoic Acid
Mouse Development

abstract: Thesis (Ph.D, Pathology & Molecular Medicine) -- Queen's University, 2007-09-28 13:49:35.17

abstract: Retinoic acid (RA) is an active metabolite of vitamin A that is essential for embryonic development, and homeostasis of adult tissues.  RA is a ligand for the nuclear retinoic acid receptor, and RA-mediated signaling is critical for regulation of cell proliferation, differentiation and apoptosis. There is a spatio-temporal distribution of RA in the developing embryo such that some tissues are rich in RA, while others are devoid.  This patterned distribution of RA is tightly controlled through the coordinated expression of RA-synthesizing (retinaldehyde dehydrogenase) and RA-catabolizing (CYP26) enzymes.  In this thesis, I describe the cloning of a mouse gene encoding one of the CYP26 proteins, Cyp26b1.  Cyp26b1 was shown to be highly expressed in the embryo, with transcripts localized to the hindbrain, limb buds and branchial arches.  We also used homologous recombination to generate a line of transgenic mice with a loss-of-function deletion in Cyp26b1.  These mice die shortly after birth with severe malformations affecting the limbs, craniofacial structures and epidermis; phenotypes that are all reminiscent of RA teratogenesis.  We present an extensive characterization of the craniofacial and epidermal abnormalities in Cyp26b1-/- animals, and examine several molecular pathways that may be deregulated.  CYP26B1 null embryos exhibit a truncated mandible, lack numerous facial bones, and show reduced ossification of the calvaria.  Molecular analysis of Cyp26b1-/- embryos indicates hindbrain and branchial arch patterning is largely unaffected in early to mid-gestational mutants.  However, there appear to be some subtle abnormalities in neural crest cell migration, which may contribute to the development of some of the observed phenotypes.  CYP26B1 null mutants also lack hair follicles, which appears to be due to a downregulation of -catenin mediated signaling.  Thus, in addition to cloning and characterizing the expression of murine Cyp26b1, we have demonstrated in vivo, that regulation of RA distribution by CYP26B1 is essential for morphogenesis of the epidermis and craniofacial structures.

abstract: PhD


title: Physical properties of a complete volume-limited sample of Ap/Bp stars: Magnetic. rotational, multiplicity, and evolutionary properties of magnetic intermediate-mass stars within 100 pc of the sun

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subject: astronomy stellar

abstract: Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2007-09-20 09:23:09.29

abstract:
The population of all magnetic chemically peculiar stars (Ap stars) within 100 parsecs of the sun has been identified and investigated, determining fundamental parameters, rotational properties, and magnetic field characteristics.

Using the HIPPARCOS Catalogue all intermediate mass stars within 100 pc of the sun have been identified.  From published catalogues and other literature sources, we have identified 57 bona fide magnetic Ap/Bp stars in this distance-selected sample.  Effective temperature, luminosity, radius, and mass were determined for each of the sample stars using published photometry and photometric calibrations, energy distributions, and HIPPARCOS parallaxes.  Using the MuSiCoS spectropolarimeter at the Pic du Midi Observatory and the Least Squares Deconvolution procedure, Stokes I and V profiles were obtained for 26 of the 57 Ap sample stars.  These observations were used in combination with previously published data to refine rotation periods, to determine projected rotational velocities, and to determine magnetic field strengths and geometries.

Using the mass statistics of the sample Ap and non-Ap stars, the mass incidence distribution of magnetic intermediate mass stars in the solar neighbourhood has been derived.  The Ap stars make up 1.7 to 2.8% (57 Ap stars out of 3904 intermediate mass stars) of all intermediate mass stars within 100 parsecs of the sun, and appear uniformly distributed across the main sequence.  Statistical distributions of various properties, including distributions of the surface dipole field strength, rotational axis inclination, magnetic obliquity angle, and rotational period were analyzed.  The rotation period distribution peaks at $2.1\pm1.1$ days, and displays an extended tail to very long periods.  The majority of Ap stars in the sample have rotational velocities below 70 km/s, although some exhibit v sin i as large as 169 km/s.  The histogram of obliquity angles shows a bimodal distribution, with a strong preference for beta angles near 0 and 90 degrees.  The derived distribution of inclination angles agrees with that found by Abt (2001) for randomly-oriented rotation axes.  The distribution of surface dipole field strengths exhibits a plateau at 2.5+/-0.5 kG, dropping off to higher and lower field strengths.  The results obtained agree with those obtained by Auriere et al. (2007), who reported a lower surface field limit at 300 G, proposing a lower limit critical field strength necessary for stable magnetic configurations to exist.

abstract: M.Sc.


title: Multiple Description Coding : proposed methods and video application

contributor:
Gazor, Saeed
Linder, Tamás
Electrical and Computer Engineering

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subject:
Multiple Description Coding
Quantization
Video

abstract: Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2007-08-19 03:33:10.451

abstract:
Multiple description coding (MDC) has received a lot of attention recently,
and has been studied widely and extended to many demanding applications such
as speech and video. MDC is a coding technique that generates correlated
descriptions of the source stream for transmitting over a diversity system
with several channels. The objective of this diversity system is to overcome
channel impairments and provide more reliability. In the context of lossy
source coding and quantization, a multiple description quantization system
usually consists of multiple channels, side encoders to quantize the source
samples and send over different channels, and side and central decoders to
reconstruct the source.

We propose two multiple description quantization schemes in
order to design the codebooks and partitions of side and central quantizers
of a multiple description system with two channels. The applied framework
originated in the multiple description quantization via Gram-Schmidt
orthogonalization approach. The basic idea of our proposed schemes is to
minimize a Lagrangian cost function by an iterative technique which jointly
designs side codebooks and partitions. Our proposed methods perform very
closely to the optimum MD quantizer with considerably less complexity.

We also propose a multiple description video coding technique motivated by
human visual perception. We employ two simple parameters as a measure of the
perceptual tolerance of discrete cosine transform (DCT) blocks against
visual distortion. We duplicate the essential information such as motion
vectors and some low-frequency DCT coefficients of prediction errors into
each description, and split the remaining high-frequency DCT coefficients
according to the calculated perceptual tolerance parameter. Our proposed
technique has very low complexity and achieves superior performance compared
to other similar techniques which do not consider perceptual distortion in
the design problem.

abstract: M.Sc.


title: Dialogical relations in a mathematics classroom

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subject:
Polyphonic discourse
Mathematics education

abstract:
This case study investigated the polyphonic discourse in a beginning secondary school mathematics classroom in Trinidad. It relates how classroom and research interview ‘talk’ contributed to students’, their teacher’s and the researcher’s developing conceptions of mathematics, themselves and each other. The study is approached from dialogical and socio-constructivist orientations.
Students and their teacher professed a diverse set of prior conceptions of
mathematics which included viewing mathematics as rule based with a problem solving orientation and emphasizing attention to the teacher. Several cases are reported that describe the authoritative elements which included a well defined structure to lessons mirroring the textbook, ‘cloze’ questions, and a reliance on rules and absent historical referents as justifications for mathematical activities and substitution for mathematical reasoning. Student and teacher questions and their desire to understand, however, served to interrupt the monological discourse. What was internally persuasive for students was the relational competency of their teacher as well as the communicative acts of their peers. Students’ responses to pedagogy were internally persuasive for the teacher and precipitated ideological assessment. Both discourse types contributed to the formation of individual as well as social identities. Student and teacher utterances were internally persuasive for the researcher.
I recommend that research needs to attend more meaningfully to what is internally
persuasive for students and teachers in mathematics teaching and learning. In addition I theorize on the need for a dialogical relationship between dialogue and pedagogy that is attentive to the ambiguities in communication.

abstract: M.Ed.


title: An early Permian subtropical carbonate system : sedimentology and diagenesis of the Raanes and Great Bear Cape formations, Sverdrup Basin, Arctic Canada

contributor: Geological Sciences and Geological Engineering

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subject:
Fusulinids
Subtropical
Diagenesis
Sverdrup Basin
Epitaxial cements

abstract: Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2007-08-21 10:58:18.958

abstract:
The Early Permian (Sakmarian to Kungarian) Raanes and Great Bear Cape formations of the Sverdrup Basin were deposited at a time of ocean cooling, and are interpreted to reflect a subtropical setting. Pelmatozoans, bryozoans, and brachiopods are the predominant fossils throughout the extent of these two units, with local occurrences of large fusulinids and colonial corals. This mixed photozoan-heterozoan assemblage is similar to the sediments of modern-day subtropical settings. Although the Raanes and Great Bear Cape have warm-water rocks below, and cool-water rocks above, the fossil assemblages in these formations were dependent upon changes in oceanography and sea-level. Three distinct phases, as determined by water depth and temperature, occur. First, the rocks of the Raanes and lower Great Bear Cape are deep water and heterozoan in nature. Second, the middle Great Bear Cape limestones record a time of shallow, subtropical waters. Finally, the upper Great Bear Cape is shallow-water, but cooling had progressed to a point that precluded the occurrence of any photozoan components, regardless of depth. Due to evolutionary changes in other subtropical biota, the most reliable fossil indicator of subtropical deposition in the rock record is large benthic foraminifera (including fusulinids) in an otherwise heterozoan assemblage. The identification of limestones representative of these conditions should, therefore, be identifiable at times in the Earth’s history when large benthic foraminifera lived in shallow marine environments.
The Great Bear Cape Formation subtropical facies underwent post-depositional changes that are manifest as calcite cements, iron-oxides, glauconite, and silica. Isopachous calcite cements precipitated in intraskeletal pore spaces as well as around the outside of grains. Glauconite, which is an authigenic marine mineral, has been oxidized to iron oxide, and both minerals post-date, or are included within, the isopachous cements. The isopachous cements must, therefore, have also formed in the marine environment. Where they are precipitated around pelmatozoan fragments, these originally high magnesium calcite cements have been neomorphosed to single-crystal epitaxial cements at the same time as mineral stabilization of the biofragments. These cements then seeded the growth of further epitaxial cement in the meteoric environment.

abstract: M.A.Sc.


title: Performance analysis of linear block codes over the queue-based channel

contributor:
Alajaji, Fady
Mathematics and Statistics

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subject:
Coding theory
Channel coding
Telecommunications
Applied mathematics
Electrical engineering
Information theory

abstract: Thesis (Master, Mathematics & Statistics) -- Queen's University, 2007-08-20 18:13:29.737

abstract:
Most coding schemes used in today's communication systems are designed for memoryless channels. These codes break down when they are transmitted over channels
with memory, which is in fact what real-world channels look like since errors often
occur in bursts. Therefore, these systems employ interleaving to spread the errors so
that the channel looks more or less memoryless (for the decoder) at the cost of added delay and complexity. In addition, they fail to exploit the memory of the channel which increases the capacity for a wide class of channels. On the other hand, most channels with memory do not have simple and mathematically tractable models, making the design of suitable channel codes more challenging and possibly not practical.
Recently, a new model has been proposed known as the queue-based channel (QBC)
which is simple enough for mathematical analysis and complex enough for modeling
wireless fading channels.
In this work, we examine the performance of linear block codes when transmitted
over this channel. We break down our focus into two parts. First, we investigate the
maximum likelihood decoding of binary linear block codes over the QBC. Since it
is well known that for binary symmetric memoryless channels, maximum likelihood
decoding reduces to minimum Hamming distance decoding, our objective here is to
explore whether there exists a similar relation between these two decoding schemes
when the channel does have memory. We give a partial answer for the case of perfect
and quasi perfect codes.
Next, we study Reed-Solomon (RS) codes and analyze their performance when transmitted over the QBC under the assumption of bounded distance decoding. In particular, we examine the two interleaving strategies encountered when dealing with non-binary codes over a binary input channel; namely, symbol interleaving and bit interleaving. We compare these two interleaving schemes analytically and show that symbol interleaving always outperforms bit interleaving. Non-interleaved Reed-Solomon
codes are also covered. We derive some useful expressions pertaining to the calculation of the probability of codeword error. The performance of non-interleaved RS codes are compared to that of interleaved ones for the simplest scenario of the QBC which is the additive (first-order) Markov noise channel with non-negative noise correlation.

abstract: M.Sc.


title: A defense framework for flooding-based DDoS attacks

contributor:
Zulkernine, Mohammad
Computing

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subject:
Network security
DDoS

abstract: Thesis (Master, Computing) -- Queen's University, 2007-08-22 23:01:20.581

abstract: Distributed denial of service (DDoS) attacks are widely regarded as a major threat to the Internet. A flooding-based DDoS attack is a very common way to attack a victim machine by sending a large number of malicious traffic. In this thesis, we propose a distance-based distributed DDoS defense framework which defends against attacks by coordinating between the distance-based DDoS defense systems of the source ends and the victim end. The proposed defense system has three major components: detection, traceback, and response. In the detection component, two distance-based detection techniques are employed. First, a distance-based technique is used to detect attacks based on a distance statistical model. Second, a statistical traffic rate forecasting technique is applied to identify attack traffic within the traffic, that are separated based on distance to the victim-end network. For the traceback component, the existing Fast Internet Traceback (FIT) technique is employed to find remote edge routers which forward attack traffic to the victim. In the response component, the distance-based rate limit mechanism quickly lowers attack traffic by setting up rate limits on these routers. We evaluate the distance-based DDoS defense system on a network simulation platform called NS2. The results demonstrate that both detection techniques are capable of detecting flooding-based DDoS attacks, and the defense system can effectively control attack traffic to sustain quality of service for legitimate users. Moreover, the system shows better performance in defeating flooding-based DDoS attacks compared to the pushback technique which uses a local aggregate congestion control mechanism.

abstract: M.Sc.


title: Regulation of inflammation by the Fps/Fes protein tyrosine kinase

contributor:
Greer, Peter A.
Biochemistry

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subject:
Lipopolysaccharide
Sepsis
Tyrosine kinase
Inflammation

abstract: Thesis (Ph.D, Biochemistry) -- Queen's University, 2007-08-27 11:39:23.393

abstract: Fps/Fes and Fer are members of a distinct subfamily of cytoplasmic protein tyrosine kinases that have recently been implicated in the regulation of innate immunity.  Previous studies showed that mice lacking Fps/Fes are hyper-sensitive to systemic lipopolysaccharide (LPS) challenge. This study identifies physiological, cellular and molecular defects that contribute to the hyper-inflammatory phenotype in Fps/Fes-null mice.  We showed that plasma tumour necrosis factor (TNF) - levels were elevated in LPS challenged Fps/Fes-null mice as compared to wild type mice, and cultured Fps/Fes-null peritoneal macrophages treated with LPS showed increased TNF- production.  Cultured Fps/Fes-null macrophages also displayed prolonged LPS-induced degradation of IB-, increased phosphorylation of the p65 subunit of NF-B, and defective TLR4 internalization.  Next, we showed a role for Fps in the regulation of recruitment of inflammatory leukocytes.  Using the cremaster muscle intravital microscopy model, we observed increased leukocyte adherence to venules, and increased rates and degrees of transendothelial migration in Fps/Fes-null mice, compared to wild type. There was also increased neutrophil migration into the peritoneal cavity subsequent to thioglycollate challenge.  Using flow cytometry, we observed prolonged expression of the selectin ligand PSGL-1 on peripheral blood neutrophils from Fps/Fes-knockout mice stimulated ex-vivo with LPS.  Finally, we examined the role of Fps/Fes in regulating apoptosis in response to inflammation. Upon intra-peritoneal challenge with LPS, Fps/Fes-null mice displayed a decreased depletion of macrophages from the peritoneal cavity.  In response to ex-vivo TNF- stimulation, macrophages from Fps/Fes-null mice underwent decreased apoptosis and necrosis as assessed by flow cytometry.  Immunoblot analysis revealed that Fps/Fes-null macrophages displayed more TNF--induced degradation of IB-α in Fps/Fes-null cells, with corresponding increases in the phosphorylation of the p65 subunit of NF-B.  In addition, stimulation of macrophages with TNF-α up-regulated PARP expression in wild-type macrophages; this up-regulation was not observed in Fps/Fes-null macrophages.  Finally we observed a decreased recruitment of macrophages to the peritoneal cavities of Fps/Fes-null mice, with a corresponding increase in neutrophil recruitment, 5 days after thioglycollate challenge.  Overall, we show that there is a role for Fps/Fes in regulating inflammation at the physiological, cellular, and molecular levels, and that this might be relevant in inflammatory disease.

abstract: PhD


title: Examining the Quick Spell Test : how does it relate to phonological processes, naming speed, orthographic processing, and reading?

contributor:
Kirby, John R.
Education

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subject:
Reading
Quick Spell Test

abstract: Thesis (Master, Education) -- Queen's University, 2007-08-23 16:08:11.688

abstract:
I examined the relationship between performance on the Quick Spell Test
(Bowers, 1996) and reading ability in an archival sample of Grade 3 (N = 192) and Grade
4 (N = 149) children from Kirby, Parrila, Deacon, and Wade-Woolley’s (2004-2007)
longitudinal study. The data included a battery of phonological awareness, naming speed,
phonological decoding, orthographic processing, and reading ability measures
administered in both grades. I found that the Quick Spell Test was a good concurrent
predictor of reading ability in Grade 3, but not a good longitudinal predictor.
Orthographic processing and phonological decoding were consistently good predictors of
the relationships between the Quick Spell Test and reading ability and of the difference in
variance between the Quick Spell Test subscales.

abstract: M.Ed.


title: Reproducing Canada's colonial legacy: a critical analysis of Aboriginal issues in Ontario high school curriculum

contributor:
Levine-Rasky, Cynthia
Sociology

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subject:
Sociology of education
Hegemony
Instrumental rationality
Apple
Gramsci
Freire
Neo-Marxist theory
Critical pedagogy
Aboriginal education
High school
Colonial history
Aboriginal issues
Curriculum

abstract: Thesis (Master, Sociology) -- Queen's University, 2007-08-23 17:38:27.532

abstract: Canadian education has historical roots in blatantly assimilationist policies bent on the social, economic, linguistic and spiritual subjugation of Aboriginal peoples and their cultures. Today, Canadian education has moved away from overtly colonialist discourses and publicly embraced the principles of multiculturalism. This research explores how and if this ideological shift has translated into the practice of contemporary Canadian education as it is experienced by students. My research focuses on the ways Canada’s colonial history and contemporary Aboriginal issues are addressed in mandatory Ontario high school social studies curriculum. This analysis is based on interviews with twenty-five recent high school graduates about what they remember learning about Aboriginal issues and how that knowledge has influenced their understanding of colonialism and Aboriginal peoples today. My interpretive analysis of students’ responses relies on the insights provided by critical pedagogy and postcolonial theory. By drawing on Gramsci, Freire and Apple I challenge the hegemonic practices in education that continue to marginalize Aboriginal peoples and their struggles. This research contributes to scholarship in the sociology of education and postcolonial studies by providing a unique picture of the ways in which young people come to understand Canada’s colonial legacy through their formal education, as well as providing insight into new directions for curriculum development, teacher training and more effective integration of anti-racist pedagogy in Ontario’s high schools.

abstract: M.A.


title: Validation of quality indicators for radical prostatectomy

contributor:
Groome, Patti A.
Community Health and Epidemiology

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subject:
Epidemiology
Oncology
Quality Indicators
Radical Prostatectomy
Prostate Cancer
Surgery
Construct Validity
Feasibility
Ontario
Quality of Care

abstract: Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2007-08-23 17:53:33.166

abstract: BACKGROUND:  Radical prostatectomy is the surgical procedure performed on men with clinically localized prostate cancer.  In recent years, radical prostatectomy quality indicators have been recommended, but the feasibility and validity for many of these listed surgical quality indicators have yet to be examined.  We tested the convergent construct validity of these quality indicators by assessing their associations with hospital volume, a variable repeatedly associated with the quality of surgical care, for prostate cancer patients treated with radical prostatectomy.  OBJECTIVES:  (1) To assess variations in quality indicators by hospital volume; and (2) To investigate whether certain explanatory variables account for some of the variation observed in Objective 1.  METHODS:  This was a retrospective cohort study using medical chart review data that had already been collected as part of a parent study.  The study population consisted of a stratified random sample of prostate cancer patients diagnosed between 1990 and 1998 in Ontario, who were treated by radical prostatectomy with curative intent within six months of diagnosis (n = 645).  The feasibility of using this data to assess a number of quality indicators was explored, and where possible, variables were developed for analysis.  Ultimately, detailed analyses were performed for the quality indicators: total blood transfusions of three units or greater, length of hospital stay, and use of non-nerve-sparing surgical technique.  RESULTS:  Even using high-quality chart data, it was not feasible to evaluate all of the quality indicators that were explored.  For blood transfusions of three units or greater, length of hospital stay, and use of non-nerve-sparing surgical technique, worse outcomes were generally apparent with decreasing hospital volume, both before and after adjusting for the effect of explanatory variables.  CONCLUSIONS:  We demonstrated convergent construct validity for three quality indicators (blood transfusions, length of hospital stay, and non-nerve-sparing surgery).  If their validity is further demonstrated in future studies, these indicators could be used for quality assessment and could provide feedback to surgeons, surgical department heads, hospital administrators, and quality councils by suggesting areas for quality improvement in surgical care, such that future outcomes can be optimized.

abstract: M.Sc.


title: Physical mobility and aging in intellectual disability

contributor:
Ouellette-Kuntz, Hélène
Hunter, Duncan
Community Health and Epidemiology

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subject:
Intellectual disability
Aging
Mobility
Health
Epidemiology
Systematic review

abstract: Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2007-08-23 22:56:48.77

abstract:
Background: The growing population of older adults with intellectual disabilities is likely to experience secondary disabilities that affect well-being.  Despite the established importance of mobility in the general population, there is little evidence of a scientific base on mobility limitations for people with intellectual disabilities.
Objectives: The aim of this study was to better understand mobility limitations in adults with intellectual disabilities, age 45 and over, by describing the prevalence and severity of mobility limitations and determining the association with living in a high support setting.
Methods: A systematic review of published literature on mobility limitations among adults with intellectual disabilities was conducted using a pre-determined search and extraction strategies.  A cross-sectional study was then conducted among a representative sample of adults, age 45 and over with intellectual disabilities in South Eastern Ontario.  Data was collected through standardized proxy response telephone surveys and analyzed descriptively to determine the prevalence and severity of mobility limitations in this population.  A multivariate logistic regression model was then used to examine the association between mobility limitations and residential status.
Results: The systematic review identified 32 publications that met all inclusion criteria.  Publications were generally not focused on mobility, cross-sectional in design and few investigators addressed key methodological features in their report.  Original data was collected for 128 older adults with intellectual disabilities.  The prevalence of mobility limitations varied according to the definition employed.  Using comparable definitions, this prevalence was higher than what is seen in the general Canadian population.  The prevalence of mobility limitations was not found to increase with age but was greater in females than males.  People with intellectual disabilities and mobility limitations had 3.6 times greater odds of living in high support residential settings than those without mobility limitations.  This difference was statistically significant.
Conclusion: Past epidemiological research on mobility limitations for people with intellectual disabilities is of poor quality.  In addressing these limitations, this study found that mobility limitations are common among people with intellectual disabilities and are associated with meaningful outcomes, such as the place in which a person lives.

abstract: M.Sc.


title: Core French in Eastern Ontario: a language-minority student's experience

contributor:
Myers, Marie J.
Education

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subject:
French
Education
Core French
Language-minority learner

abstract: Thesis (Master, Education) -- Queen's University, 2007-08-24 13:27:50.613

abstract: This qualitative case study was conducted to learn about the experiences of one language-minority student learning French in a core French class in Eastern Ontario. In-class observations and interviews with the language-minority learner (LML), his guardian, his teachers and principal were conducted over a six-week period. The data collected helped to create a thick description of the LML’s experiences. The results of the study show that the institution, family and friends all play a role in the LML’s experiences in learning French. It was found that the use and availability of resources, possible curriculum modifications, and effective teaching and learning strategies for language-minority students are important factors affecting the experiences of the LML. This study shows that peers have a strong influence on the experiences of the LML in learning French in the core French context. Finally, the Canadian School Stay program came under scrutiny and information was gleaned from the regional coordinator. Suggestions are made for improved content delivery and further research.

abstract: M.Ed.


title: Type-Safe Computation With Heterogeneous Data

contributor:
Skillicorn, B. David
Computing

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subject:
Pattern Structure
Pattern Calculus
Generic Programming
Heterogeneous Data
Type Safety
XML Processing
Java Bytecode Checking

abstract: Thesis (Ph.D, Computing) -- Queen's University, 2007-08-27 09:43:38.888

abstract:
Computation with large-scale heterogeneous data typically requires universal traversal to search for all occurrences of a substructure that matches a possibly complex search pattern, whose context may be different in different places within the data. Both aspects cause difficulty for existing general-purpose programming languages, because these languages are designed for homogeneous data and have problems typing the different substructures in heterogeneous data, and the complex patterns to match with the substructures. Programmers either have to hard-code the structures and search patterns, preventing programs from being reusable and scalable, or
have to use low-level untyped programming or programming with special-purpose query languages, opening the door to type mismatches that cause a high risk of program correctness and security problems.

This thesis invents the concept of pattern structures, and proposes a general solution to the above problems - a programming technique using pattern structures. In this solution, well-typed pattern structures are
defined to represent complex search patterns, and pattern searching over heterogeneous data is programmed with pattern parameters, in a statically-typed language that supports first-class typing of structures and patterns. The resulting programs are statically-typed, highly reusable for different data structures and different patterns, and highly scalable
in terms of the complexity of data structures and patterns. Adding new kinds of patterns for an application no longer requires changing the language in use or creating new ones, but is only a programming task. The thesis demonstrates the application of this approach to, and its
advantages in, two important examples of computation with heterogeneous data, i.e., XML data processing and Java bytecode analysis.

abstract: PhD


title: The poetics of cultural healing: Derek Walcott's Omeros and the modernist epic

contributor:
Rae, Patricia
English

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subject:
Walcott, Derek
Modernist
Epic
Modern poetry

abstract: Thesis (Ph.D, English) -- Queen's University, 2007-08-27 11:56:30.559

abstract:
This thesis examines the complex intersections between Derek Walcott’s Omeros and modernist versions of the epic. Critics generally acknowledge the pervasive presence of modernist allusions in Walcott’s early work, but see the relevance of modernism diminishing as Walcott develops his “mature” poetic strategies of mimicry and hybridity. I challenge this reading of Walcott, arguing that the modernist practices of Ezra Pound in The Cantos, T.S. Eliot in The Waste Land, and Hart Crane in The Bridge are crucial to illuminating the central theme of cultural healing in Walcott’s most ambitious work, Omeros. These four authors share the goal of creating an epic poem that encapsulates the experiences of modernity (the modern epic). Walcott adopts and transforms elements from The Cantos, The Waste Land and The Bridge in order to articulate the complex relations among self, tradition, land, and language that can allow the postcolonial subject to overcome the traumatic legacy of imperialism in the Caribbean. I define the relation between Omeros and its modernist intertexts according to this pattern of imitation and divergence (which Joseph Farrell calls the pattern of imitatio and aemulatio in the epic tradition).
I organize my dissertation into four chapters, each focused on a particular issue: the process of redefining the epic, the construction of indigenous status by means of myth and imperialism, the search for alternative modes of understanding the past that would resist the hegemony of chronological history, and the mystical process of cultural healing that synthesizes the human, the divine, and the natural world. This study demonstrates the tremendous utility and ideological ambiguities generated by the specific practices of
ii
literary modernism when Walcott deploys them to articulate his cultural vision. My approach to Omeros provides a corrective to the critical tendency to view modernism in the postcolonial milieu as either the postcolonial artist’s response to the conditions of modernity or as a tradition whose form and meaning is radically transformed by a postcolonial vision. Walcott’s relation to modernism suggests that this postcolonial cultural vision is itself shaped by modernist poetics in ways that both empower and constrain.

abstract: PhD


title: Infants reason about functional information embedded in means-end sequences

contributor:
Kuhlmeier, Valerie
Psychology

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subject:
Means-end sequences
tool-use
infants

abstract: Thesis (Master, Psychology) -- Queen's University, 2007-08-28 11:26:07.974

abstract: For young infants, knowledge of physical objects and animate agents seems highly rigid, with no information combined across domains.  Adult cognition, however, is more flexible.  In this thesis, I use a special category of object—a tool—that can only be reasoned about appropriately if information is combined across domains.  Using this special case, I examine whether older infants are capable of integrating functional information about the tool while making inferences about the intent of the tool-user.  Experiment 1 shows that infants can reason about complex means-end sequences involving tools; and Experiments 2 and 3 both show that under some circumstances, infants can take into account functional information about the tool when making these sorts of inferences.  Together, these studies extend previous findings about how infants understand complex means-end sequences, and demonstrate that by 13 months, infants are already combining knowledge across domains.

abstract: M.Sc.


title: Tinker, Tory, Wobbler, Why? : the political economy of electricity restructuring in Ontario, 1995-2003

contributor:
Little, Margaret
Political Studies

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subject:
Political Science
Ontario Politics
Political Economy
Electricity Policy

abstract: Thesis (Ph.D, Political Studies) -- Queen's University, 2007-08-27 23:05:37.549

abstract:
The Ontario Tories' 42-year hegemony in government (1943-1985) was wrought through clever policies which often utilized Crown institutions to promote prosperity or to oblige or mollify vying interests.  Ousted in 1985, though, they used their time in opposition to revise the Tory doctrine.  In the 1995 election, the Tories emerged a tougher, more truculent group quite unlike their predecessors.  Campaigning on their Common Sense Revolution (CSR) platform, they promised to eliminate red tape and vowed to obliterate all ostensible economic barriers which were impeding commerce in the province.  In the CSR, the Tories identified Ontario Hydro (OH), the province's lauded publicly-owned power monopoly, as a troublesome and inefficient Crown entity which required fundamental reform.  Portions of OH, they hinted, would likely be sold.  Once elected, the Tories worked hurriedly to demolish OH and destroy public power in Ontario.
	For nearly 100 years, OH proved a pivotal component within the province's political economy for its provision of affordable, reliable power and its function as a policy tool to incite and direct development.  A Tory government fought to instigate public power in the early 1900s and, in the late 1900s, a Tory government was fighting vigorously to rescind it.  Why would they now renounce Crown power?
	It is the intent of this thesis to elucidate the Tory government's involvement in the transformation of Ontario's electricity industry from 1995 to 2003.  Distinguishing electricity as a special, strategic staple, this thesis uses a pro-state, pro-staples industry political economy approach to discern how and why the Tory government sought to restructure the electricity sector.  Essentially, it posits that the onslaught of neoliberalism, the emergence of novel generating technology, and the faltering of OH's nuclear wing all had a huge part to play in provoking the Tory government to initiate its reforms.  Their reforms, though, proved too hasty, haughty, and fraught with ambiguity to work properly.  While their open, competitive power market and attempts to privatize Hydro One failed horribly, the Tories' energy re-regulation strategy did hold promise to allow the state to retain a prominent role in the power industry.

abstract: PhD


title: Donor Portraits in Late Medieval Venice c.1280-1413

contributor:
Osborne, John
Art History

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subject: Portrait Italy Medieval Art

abstract: Thesis (Ph.D, Art History) -- Queen's University, 2007-08-28 08:55:06.214

abstract:
Although the donor portrait was extremely popular throughout Europe and mainland Italy during the late Middle Ages, the few art historians who have addressed the subject have concluded that the motif was not popular in fourteenth-century Venice. The political structures of Venice and its citizens’ supposedly innate abhorrence of public expressions of individuality in the Republic are often cited as reasons for the absence of individual donor portraits; the examples that have survived are commonly interpreted as direct reflections of state or communal values.
This dissertation challenges these previous conclusions and poses the following questions: Was donor portraiture popular in Venice, and in what forms? And how did the appearance and function of donor portraits in Venice compare with those from Europe and Byzantium? The evidence examined here includes a catalogue of 83 examples dated approximately between 1280 and 1413. I have attempted to reconstruct the social, political, and physical environments for these examples, and for those images that have been lost through centuries of changing trends and political upheaval. Through case studies of donor portrait subjects from a cross-section of Venetian society, including doges, nobles, cittadini, confraternity groups, and patrician women, it becomes clear that such images were, in fact, popular in late medieval Venice and that they were mostly intended for public viewing. Furthermore, the fact that donor portraits are rarely mentioned in the extant documents suggests that such imagery was considered conventional and that it posed no significant threat to the ideology of the Venetian state.
Further examination of these visual documents, and analyses of socio-historical developments in the period indicate that donor portraits in Venice, like similar portraits in Byzantium and mainland Italy, mainly reflect personal concerns about family, status, wealth, and salvation. Their physical appearance likewise suggests that these images were intended for display within the confines of city parishes and that ultimately, in this context, donor portraiture in late medieval Venice was no more likely to reflect state ideologies than donor portraiture in other parts of Europe.

abstract: PhD


title: Measuring the influence of winter conditions on largemouth bass behaviour using both biotelemetry and laboratory studies

contributor:
Tufts, Bruce L.
Biology

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subject: Ecology Biotelemetry

abstract: Thesis (Master, Biology) -- Queen's University, 2007-08-28 13:59:30.215

abstract:
Studying the winter ecology of freshwater fishes has been a focus of much past and present research.  Because of obvious constraints with studying fish in situ during the winter, few studies have made links between laboratory findings and observations made in the natural environment.  Recently, new developments in biotelemetry have provided a way of assessing the winter ecology of fish in a natural setting. At present, however, there are few, if any, studies that attempt to make direct links between field and laboratory results.
	This research focuses on the reaction of largemouth bass (Micropterus salmoides) to winter conditions using both biotelemetry and laboratory components.  In the first part of the study, biotelemetry-derived swimming activity is assessed across a range of temperatures (4.0-25°C).  As well, swim tunnel-derived Ucrit swimming speeds and burst swimming ability across similar temperatures were evaluated.  In both cases, swimming activity and speeds decreased as temperatures decreased.  In biotelemetry-derived measurements, swimming activities increase late in winter, possibly suggesting acclimatization.
	In the second part of the study the effect of hypoxia on winter habitat selection was investigated.  Biotelemetry-obtained locations of largemouth bass were compared to the distribution of dissolved oxygen throughout the lake at numerous times throughout the winter.  In addition, experiments were conducted in a laboratory setting on winter juvenile fish to determine the behavioural and physiological impacts of hypoxia.  The results of these experiments revealed a behavioural response in the lab and habitat avoidance in the field at an environmental oxygen level of approximately 2 mg/L of dissolved oxygen.
	The combination of biotelemetry with laboratory data has demonstrated that more informative results about the winter ecology of freshwater fishes can be derived.  In the future, usefulness of this combined approach in assessing the impacts of climate change on fish populations will be invaluable.

abstract: M.Sc.


title: Urban Agriculture in Kingston:  Present and Future Potential for Re-localization and Sustainability

contributor:
Blay-Palmer, Alison
van Loon, Gary
Smith, Mick
Environmental Studies

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subject:
urban agriculture
sustainability
food systems
local food
triangulation

abstract: Thesis (Master, Environmental Studies) -- Queen's University, 2007-08-28 14:26:18.048

abstract: Urbanization and the globalization of the food system are causing social, environmental, economic and political problems worldwide.  Rapid urbanization is increasing environmental degradation and food insecurity.  Urban agriculture is one tool for sustainable development that has the potential to provide food or related services within or on the edges of urban areas.  The goal of this research was to determine the current situation and the future potential of urban agriculture in Kingston.  A literature review, questionnaires, interviews and case studies were used to determine the perceptions of relevant stakeholders, barriers and ways to overcome those barriers.  Conservative estimates of urban agriculture's value to Kingston's environmental, social, community health, food security and economic dimensions were made through modeling.  Study participants demonstrated a relatively greater awareness of environmental and community benefits of urban agriculture compared to food security, health or economic benefits.  Modeling and calculations indicated that urban agriculture could contribute at least $190 to $860 million per year in positive environmental, health and economic benefits.  Modeling indicated that sourcing more local urban produced foods could reduce greenhouse gas emissions by at least 1300 to 14000 tonnes annually for 39 common fresh fruits and vegetables.  Urban agriculture could meet the fresh fruits and vegetables needs of up to 76% or more of the Kingston CMA population.  There appeared to be 5600 ha of area in the inner-city that could be used for food production.  Major challenges identified were perceptions of limited space, limited resources and education.  Recommendations to address these challenges are also provided.  Overall, urban agriculture has potential to contribute to sustainability in Kingston.

abstract: M.E.S.


title: A Study of the Performance of Tool-Mounted Displays for Surgical Guidance

contributor:
Stewart, James
Computing

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subject:
Computer Science
Computer-Assisted Surgery
Visualization
Tool Guidance
Hand-Held

abstract: Thesis (Master, Computing) -- Queen's University, 2007-09-18 00:31:10.965

abstract:
In computer-assisted surgery, a computer display provides 3D guidance of tools during surgery.  However, current guidance displays have a number of drawbacks.

This thesis considers the advantages of a prototype guidance system for drilling tasks.  We attached a small LCD screen and video camera to a surgical drill.  The screen's point of view was controlled by moving the drill.

A user study showed that the tool-mounted LCD screen can provide significantly better positional and angular accuracy than the conventional display.  The study also showed that a video camera might not be useful for guidance.

abstract: M.Sc.


title: Transition into School: Experiences of Children with Intellectual Disabilities and their Families

contributor:
Minnes, Patricia
Psychology

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subject:
intellectual disability
transition to school

abstract: Thesis (Master, Psychology) -- Queen's University, 2007-08-28 15:35:10.833

abstract:
A successful transition into kindergarten is of the utmost importance, as it marks the beginning of formal education and paves the way for future academic and social outcomes. The transition into school is considered to be a challenging and anxiety-ridden time for most children and their parents; it is expected therefore, to be particularly difficult for children with an intellectual disability (ID). These children have deficits in cognitive and adaptive functioning that affect their academic and social skills. Despite the apparent difficulty for children with ID and the importance of this time in their lives, the transition into school has been a relatively under-researched topic.
Nineteen parents of children with ID participated in three one-hour phone interviews throughout the transition into school. The aims of the study were 1) to describe this group of children with ID and their families as the children entered school, 2) to investigate changes in characteristics of the child, resources, and perceptions of the parent during the transition, and 3) to examine relationships between these variables and the child’s quality of life and school readiness. Although the results are based on a small sample, they do provide some preliminary information about the experiences of children with ID and their families throughout the transition into school. Only adaptive behaviour scores and the number of services accessed changed significantly during the time of transition. Furthermore, it was found that adaptive behaviour was correlated with school readiness skills, as were physiotherapy and speech-language therapy use. The only variable that correlated with the child’s quality of life was parental involvement in parent support groups. Implications and directions for future research are discussed.

abstract: M.Sc.


title: Transition metal catalyzed hydroborations with pinacolborane: new applications and mechanistic investigations

contributor:
Crudden, Cathleen M.
Chemistry

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subject:
Hydroboration
Pinacolborane
Rhodium
Iridium
Transition metal
Catalysis

abstract: Thesis (Ph.D, Chemistry) -- Queen's University, 2007-08-29 09:30:38.571

abstract:
A methodology for the catalytic asymmetric hydroboration of vinylarenes with pinacolborane has been developed.  Use of pinacolborane in hydroboration, especially catalytic asymmetric hydroboration grants direct access to chiral boronate esters, without the cryogenic temperatures required for catalytic hydroboration with catecholborane and the subsequent transesterification with excess pinacol.  These chiral boronate esters were then subjected to a homologation/oxidation sequence previously refined in our labs to prepare Naproxen™ in 66% yield and 88% enantiopurity from its corresponding vinyl arene precursor.

A survey of metal catalysts, solvents and ligands revealed remarkable changes in regioselectivity with changes in metal.  Rhodium catalysts in combination with pinacolborane were able to provide regioselectivity for the secondary branched isomer equivalent to those obtained with catecholborane.  Iridium catalysts showed a near perfect regioselectivity for the primary linear isomer.  With respect to the choice of chiral ligand, complete reversal in the enantiomer obtained was observed with the choice of hydroborating reagent from catecholborane to pinacolborane.

In order to understand the regioselectivity observed under iridium catalysis, deuterium labeling studies were undertaken.  A synthesis of the deuterated hydroboration reagent pinacolborane was first completed.  From the results of these studies, in combination with published thermodynamic data, a mechanism for the iridium catalyzed hydroboration of alkenes was proposed.

abstract: PhD


title: Representation of object dynamics for action

contributor:
Flanagan, J. Randall
Neuroscience Studies

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subject:
Motor control
Internal model

abstract: Thesis (Master, Neuroscience Studies) -- Queen's University, 2007-08-29 10:57:23.511

abstract: The human hand has evolved to be remarkably good at skillfully manipulating objects. This manipulation requires knowledge of the dynamic properties of an object, which is represented in the central nervous system (CNS) by what has been referred to as an internal model. Internal models are neural representations of the predicted behaviour of objects or limbs with a known state in response to a given motor command. Our ability to successfully manipulate a wide variety of objects suggests that the CNS maintains multiple internal models of familiar object dynamics. People are able to both recruit these models for use when an object is grasped and to rapidly switch to another model when the object is exchanged. The purpose of this study was to investigate how internal models of objects are accessed and used for action. In experiment 1, subjects learned to move a cursor to a target by manipulating a robotic arm with complex dynamics. We used event-related fMRI to measure the neural activity associated with grasping the robot handle in preparation for movement. In comparison to control tasks, subjects showed significant neural activation in the ipsilateral cerebellum and the contralateral primary motor and supplementary motor areas, suggesting the likely involvement of these areas in recruitment of internal models. In experiment 2, we used a precision lifting task to investigate how the internal representation of weight asymmetry transfers across changes in hand, hand orientation and object orientation. Subjects demonstrated positive transfer in all cases when the hand was rotated, indicating that internal models of objects can be adapted to accommodate changes in hand orientation. When the object was rotated, positive transfer was seen only when the hand also rotated, suggesting that this change in hand orientation facilitated mental rotation of the object. Overall, these results support the idea that people maintain an internal representation of object dynamics but can not always link this model to the configuration of the object in space.

abstract: M.Sc.


title: A Study of Rhodium Catalyzed Hydroborations and Sulfur ylide Epoxidations

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subject:
Sulfur ylide
Epoxidation
Hydroboration
Regioselectivity

abstract: Thesis (Ph.D, Chemistry) -- Queen's University, 2007-08-29 17:56:36.642

abstract:
A rhodium-catalyzed process has been developed in which mixtures of internal and terminal olefins are isomerized and hydroborated in one step yielding the corresponding terminal pinacolboronates.  Homologation and subsequent oxidation regiospecifically affords the terminal aldehyde in what amounts to a one-pot CO free hydroformylation.  Good overall yields are obtained in all substrates examined.  In a related study, mechanistic aspects of the rhodium catalyzed hydroboration of vinyl arenes have been probed.  A combination of substituent effects (Hammett study), deuterium labeling studies and heavy atom isotope effects has demonstrated mechanistic differences in the hydroboration of electron rich and electron poor substrates.  The results of the study further demonstrate the differences in reaction mechansim for hydroborations mediated with catecholborane versus pinacolborane.

The Corey-Chaykovsky reaction, in which an aldehyde and a sulfur ylide are coupled to yield an epoxide has proven to be a versatile and valuable method for the production of epoxides.  The reaction between benzaldehyde and benzyldimethylsulfonium tetrafluoroborate has been subjected to a kinetic analysis.  Activation parameters were determined for the reaction and a large negative ΔS‡ of -35 cal/mol/K was calculated for the epoxidation of benzaldehyde.  A large carbon kinetic isotope effect of 1.026 and an inverse deuterium isotope effect of 0.93 were determined for the reaction.  A large positive Hammett ρ of +2.50 was found for the epoxidation of various substituted benzaldehydes by competition experiments.  These results aided in the identification of the rate limiting step as addition of the ylide species to benzaldehyde.  In a separate, although related study, the mechanism of the collapse of hydroxysulfonium salts has been examined with regard for implications in the epoxidation of aldehydes.  The anti-diastereomer reacted with complete retention of stereochemistry and no crossover, while the syn-diastereomer gave crossover products along with cis and trans epoxides. Deprotonation and re-protonation on the carbon of the alpha-hydroxy sulfonium ylide was responsible for production of the trans epoxide as demonstrated by deuterium labeling.

abstract: PhD


title: More than just 'notorious': critical considerations of gender in the early history of Kingston Penitentiary

contributor:
Snider, Laureen
Sociology

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subject:
Gender
Kingston Penitentiary

abstract: Thesis (Master, Sociology) -- Queen's University, 2007-08-30 09:23:28.414

abstract: For centuries, scholarship in the area of punishment, prisons and corrections has been generated by a number of different disciplines. It is difficult to argue the fact that there has been a bias in this literature toward discussions of the crimes and punishments of men. Given the historically disproportionate representation of men in criminal justice systems worldwide, the male ‘inmate’ has undoubtedly become the taken-for-granted norm in penality studies. However, works on ‘male imprisonment’ versus ‘female imprisonment’ (particularly feminist works) demonstrate a significant disparity in their approach. Despite the extensive nature of scholarship on penality, and the strong focus on gender by feminist scholars in the area, there has been a vast silence on the incarcerated male as a gendered subject, and the male prison as a gendered institution. Although this silence has been briefly noted by feminist scholars in their discussions of female imprisonment (e.g. Hannah-Moffat 2001; Howe 1994; Naffine 1996), few scholars to date have taken up a critical discussion of gender in the context of male incarceration. This oversight is especially characteristic of Canadian penal scholarship and Canadian penal histories in particular. It is the aim of this work to initiate the ‘catch-up,’ to engage in a historical examination of male penality in Canada that draws upon a number of the developments made in both the critical literature on punishment – predominantly focusing on the incarceration of men – and feminist scholarship’s gender approaches to women’s incarceration. Arguably, there is no better point to start this inquiry than with Kingston Penitentiary, Canada’s oldest and long-considered most ‘notorious’ prison for men. Using historical documents from the early history of Kingston Penitentiary (1833-1856), an analysis of discourse using a Foucauldian feminist theoretical approach is performed to uncover the gendered nature of the institution, and the policies and procedures developed for inmate men. Findings suggest that gendered power relations involving a number of different strategies (benevolence, control, pastoralism) and masculinities (aggressive, vulnerable, etc.) were at work. Implications of viewing prisons for men as gendered institutions are discussed.

abstract: M.A.


title: The effects of botulinum toxin A (BTX-A) on gait in chronic stroke

contributor:
Brouwer, Brenda
Neuroscience Studies

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subject:
Stroke
Gait
Muscle stiffness
Botulinum toxin A

abstract: Thesis (Master, Neuroscience Studies) -- Queen's University, 2007-08-30 09:41:03.24

abstract: Excessive muscle tone or stiffness secondary to stroke frequently involves the ankle plantarflexors and has been associated with decreased mobility and reduced function.  Although becoming more common in clinical practice, the effectiveness of botulinum toxin A (BTX-A) injected in the ankle plantarflexors on gait biomechanics is not well established.  The primary objective of this study was to describe the kinematic and kinetic changes that occur during walking following BTX-A treatment of the hypertonic ankle plantarflexors.  As well, the study explored whether there were clinical characteristics uniquely associated with subjects that exhibited biomechanical improvement.  The study was a single group, open label trial with repeated measures, including multiple baseline and three post-intervention time points.  Seven chronic hemiparetic stroke subjects with ankle hypertonicity were included in the study.  Full lower limb bilateral gait analysis provided joint kinematic and kinetic information throughout stance.  As well, clinical measures of ankle range of motion and spasticity were assessed pre and post treatment.  Data were analyzed using paired samples t-tests and repeated measures ANOVA with Least Significant Difference adjustment for post-hoc analysis as necessary (significance level p≤0.05).  Of the kinematic variables, significant improvements in peak dorsiflexion and plantarflexion and the ankle angle at initial contact were found 10 weeks post-injection relative to baseline. No significant kinetic changes were detected, however 2 subjects showed improved positive work at the ankle post-injection and 5 subjects demonstrated increased positive work at the hip post-treatment.  Although subjects were classified as “responders” or “non-responders” based on clinical improvement observed 2 weeks post-injection, there was no observable association between those who responded clinically and those who demonstrated improved gait. The major findings suggest that BTX-A injection results in tone reduction and in some cases improves the biomechanical efficiency of gait. In cases where kinetic variables remained unchanged following treatment, perhaps the increased tone was not the limiting factor of reduced function.

abstract: M.Sc.


title: Simulation of wrist kinematics on the basis of a rigid body spring model

contributor:
Sellens, Rick
Mechanical and Materials Engineering

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subject:
Wrist kinematics
Rigid body spring model

abstract: Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2007-08-30 16:30:32.543

abstract:
The purpose of this thesis was to create a computational wrist model that predicts carpal bone motion in order to investigate the complex kinematics of the human wrist. The tuning of this model was primarily based on in vitro, kinematic measurements of the carpal bones obtained from the same cadaver arm as the geometry for the model was generated.

A rigid body spring model of the wrist was built using the kinematic simulation software RecurDynTM 6.1. Surface models of the eight carpal bones, the bases of the five metacarpal bones, and the distal parts of the ulna and radius, all obtained from computed tomography (CT) scans of a cadaver upper limb, were utilized as the geometry for this model. Elastic contact conditions between the rigid bodies modeled the influence of the cartilage layers, and ligamentous structures were constructed using nonlinear, tension-only spring elements. Motion of the wrist was simulated by applying forces to the tendons of the five main wrist muscles modeled.

Three wrist motions were simulated: extension, ulnar deviation and radial deviation. The model was mainly tuned by comparing the simulated displacement and orientation of the carpal bones with previously obtained CT-scans of the same cadaver arm in deviated (45 deg ulnar and 15 deg radial), and extended (57 deg) wrist positions. Simulation results for the scaphoid, lunate, capitate, hamate and triquetrum are presented here and provide credible prediction of carpal bone movement. The impact of certain model parameters on simulation results has been investigated by performing sensitivity analyses, and their severity has been documented.

The results of the first simulations indicate that this model may assist in future wrist kinematics investigations. However, further optimization and validation are required to define and guarantee the reliability of this model. It is suggested that this rigid body spring model may be part of an interacting framework between in vitro and in vivo investigations, as well as other computational models, in order to improve and complement each biomechanical investigation method.

abstract: M.A.Sc.


title: A numerical study of an autothermal reformer for the production of hydrogen from Iso-octane

contributor:
Oosthuizen, Patrick H.
Mechanical and Materials Engineering

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subject:
Autothermal reforming
Iso-octane
Reactor modeling

abstract: Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2007-08-31 13:22:27.466

abstract: The development of an auxiliary power unit (APU) capable of providing climate control and electricity in long haul trucks is of significant interest due to the expected economic and environmental benefits.  A potentially efficient and environmentally friendly APU design is one based on the use of an autothermal fuel reformer that converts on-board truck fuel to a hydrogen rich gas that directly fuels a solid oxide fuel cell unit.  To assist in the development of such a unit a numerical study of the autothermal reforming of iso-octane in a compact tubular reactor has been undertaken.  This was done to determine the reactor performance and the factors that potentially influence its performance.  Variations in the wall thermal conductivity, the catalyst thermal conductivity, the catalyst porosity, the conditions of the inlet reactant gas, and the effectiveness factor of the chemical reaction mechanism have been studied to determine their effects on the performance of the reformer.  It has been found that higher thermal conductivities of the outer wall and in the catalyst region gave increased dry hydrogen yield and fuel conversion.  The study of the effects of inlet species concentration ratios indicated that maximum hydrogen yield was obtained with an oxygen-to-fuel ratio between 1.0 and 1.15 and a steam-to-fuel ratio of approximately 3.0.  Results obtained with various inlet species temperatures and bed porosities showed only small changes in the reformer performance.  While the results obtained here do provide useful information about the performance of the autothermal reformer, the model used has been re-assessed and it is recommended that an improved model be used in future work.  In particular, the assumed effectiveness factors for all of the chemical reactions occurring in the catalyst region need to be improved.  This was highlighted by the fact that a brief study indicated a very strong dependence of the reformer product gas composition on the effectiveness factor.  This indicates that while the present model is able to predict trends in the reformer performance, it is limited in its accuracy due to the fact that the effectiveness factor used is only approximately known.

abstract: M.A.Sc.


title: The law of peoples, human rights and minority rights: a study of legitimacy and international justice

contributor:
Kymlicka, Will
Philosophy

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subject:
Political philosophy
Human rights
Minority rights
John Rawls
Will Kymlicka
Law of peoples

abstract: Thesis (Master, Philosophy) -- Queen's University, 2007-09-05 10:41:44.771

abstract:
Severe poverty and ethnic-conflicts are the two most devastating problems of the contemporary world. Eighteen million persons die every year from causes related to poverty and a vast amount of developing countries suffer from tremendous processes of destabilization –frequently involving highly violent actions– associated to the relations between majority and minority groups. In both cases, the intervention of international powers and institutions has not been helpful enough to make a difference, and this present reality projects itself as a distressing scene for the future. Human rights and minority rights are the most powerful international tools in trying to change this sad global scenario. However, there is an extensive debate on the nature of these rights in a theory of international justice. This is often characterized as a debate between “minimalist” who seek to reduce the currently –recognized list of human rights to a bare minimum in order to accommodate non-liberal societies, and more expansive liberal approaches, which seek to expand the list of human rights to include the full set of civil and political rights characteristic of modern liberal-democracies. In this thesis, I will argue in favour of a third position. In line with some of the more minimalist approaches, I will argue that constraints of legitimacy rule out attempts to include full civil and political rights into our list of human rights. However, I will argue that these same constraints of legitimacy advocates for expanding the currently-recognized list of human rights in at least two key respects: the recognition of certain basic social and economic rights; and the recognition of certain minority rights. In short, we should be minimalist on some issues, while more expansive in others.
In developing this argument, I will relay on the framework provided by The Law of Peoples of John Rawls.

abstract: M.A.


title: Characterizing ErbB2-induced mammary tumourigenesis

contributor:
Elliott, Bruce E.
Pathology and Molecular Medicine

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subject:
ErbB2
Breast Cancer
Src
FAK
Akt

abstract: Thesis (Master, Pathology & Molecular Medicine) -- Queen's University, 2007-08-31 16:25:59.917

abstract: Approximately 30% of human breast cancers demonstrate overexpression of the receptor tyrosine kinase ErbB2/HER2/Neu, with these cases correlating with recurrence and poor prognosis.  While therapy targeting ErbB2 has met with some success, particularly in early-stage breast cancers, transformation and progression towards a later-stage metastatic phenotype is likely sustained by aberrant signaling from additional players, for instance that downstream of integrins.  In fact, treatment with integrin-blocking antibodies and ß1-integrin ablation leads to reversion of the malignant phenotype of human breast cells in three-dimensional culture and in vivo.  Moreover, ErbB2 has recently been found to interact with the ß4-integrin subunit to promote tumour formation and progression, as deletion of the ß4-integrin signaling domain led to suppression of mammary tumour onset and invasive growth, coupled with decreases in ErbB2-dependent signaling.  ErbB2 may interact with integrin subunits by direct binding or via the intracellular kinases Src and focal adhesion kinase (FAK), both known to be activated downstream of ErbB2 and integrins and having well-established roles in cell adhesion, migration, and invasion.  Using an inducible model of ErbB2 activation, we have demonstrated that controlled ErbB2 activation in human mammary epithelial cells leads to phosphorylation of Src Tyr215 and FAK Tyr861, consistent with a recently published clinical study examining phosphorylated forms of Src and FAK in ErbB2-positive human breast tumour samples.  We have also confirmed that ErbB2 activation increases the capacity of cells for survival: Normally, MCF10A human mammary epithelial cells cultured in three-dimensional, laminin-rich extracellular matrix gel form mammary acini-like spheroids with hollow lumen surrounded by a single layer of polarized epithelial cells.  However, ErbB2 activation prevents luminal clearance and induces luminal filling in acini formed in three-dimensional culture, and leads to activation of Akt, a known survival signal.  Taken together these data indicate a potential role for ErbB2 at the apex of cell survival signaling via Src, FAK, and Akt, contributing to luminal cell survival in three-dimensional culture.  We have thus confirmed Src, FAK, and Akt as potential players in early onset of breast cancer, and targeting these signaling players concurrently with ErbB2 may prove effective, especially in early stage breast cancers.

abstract: M.Sc.


title: Investigation into the relationship between Physical Activity and Homocysteine

contributor:
King, Will D.
Casson, Ian
Massey, Thomas E.
Community Health and Epidemiology

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subject:
Physical activity
Homocysteine

abstract: Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2007-09-25 11:19:23.321

abstract:
Background:  A beneficial effect of physical activity on the risk of cancer at several sites has been consistently observed. Biologic mechanisms that may underlie this relationship are not well understood. A potential mechanism explaining this relationship for some cancer sites is the influence of physical activity on methionine-homocysteine biosynthesis. High levels of total plasma homocysteine concentration (tHcy) indicate a breakdown in this biochemical process. This cycle’s influences on DNA methylation and endogeneous agents involved in oxidative stress are potential mechanisms linking methionine-homocysteine biosynthesis to cancer risk. This research is nested within a larger cross sectional study of healthy volunteers recruited from centers in Ontario and Nova Scotia aimed at understanding modifiable risk factors for cancer.

Purpose: This research sought to elucidate the relationship between physical activity and tHcy level.

Methods: The target population was healthy male and female subjects aged 20-50. Participants donate a 12ml blood sample after an overnight fast for analysis of tHcy and dietary factors and complete a questionnaire including a physical activity profile for the past month (adapted from the International Physical Activity Questionnaire [IPAQ]) and established predictors of tHcy level such as coffee and alcohol consumption. Multiple linear regression is used to model the relationship between tHcy and physical activity measures while controlling for potential confounders.

Results: Analysis on 171 participants has been carried out. Mean tHcy for five quintiles of physical activity (from lowest physical activity score to highest) were found to be 8.40μmol/L (7.76-9.05), 8.60μmol/L (8.00, 9.22), 9.24μmol/L (8.66, 9.81), 8.23 μmol/L(7.64, 8.82), and 8.70μmol/L (8.09, 9.31).

Conclusions: The findings of this research do not support a relationship between physical activity and total plasma homocysteine concentration. Results of this study suggest that homocysteine is not a mediating factor for the relationship observed between physical activity and cancer.

abstract: M.Sc.


title: Magnetic, chemical and rotational properties of the Herbig Ae/Be binary system HD 72106

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subject: Astronomy Astrophysics

abstract: Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2007-09-04 14:48:02.487

abstract:
Recently, magnetic fields have been detected in a handful of pre-main sequence Herbig Ae and Be (HAeBe) stars. This hints at an evolutionary connection between magnetic HAeBe stars and Ap and Bp stars. Ap/Bp stars are magnetic chemically peculiar main sequence stars, whose origins remain poorly understood.
In this context the HD 72106 system, a very young double star, is particularly interesting. HD 72106 consists of an intermediate mass primary with a strong magnetic field and an apparently non-magnetic Herbig Ae secondary. In this work we examine 20 high-resolution spectropolarimetric observations of HD 72106A and B, obtained with the ESPaDOnS instrument at the Canada-France-Hawaii Telescope. We find that the HD 72106 system is a true binary, based on the components' positions in space, locations on the H-R diagram, and dynamical properties. For the primary we determine an effective temperature Teff = 11000 ± 1000 K and a mass of 2.4 ± 0.4 M ; while for the secondary we find Teff = 8750 ± 500 K and M = 1.9 ± 0.2 M .
Through detailed spectral modeling, strong chemical peculiarities characteristic of Ap/Bp stars are found in the primary. Abundances of 10 times the solar value are found for Fe, Si and Ti, with Cr 100 times solar and Nd  1000 times solar. Helium is found to display less than 1/10 the solar abundance. By contrast, detailed spectrum modeling of the secondary shows that it possesses approximately solar abundances.
The rotation period and magnetic field geometry of the primary are investigated in detail. A remarkably short rotation period of 0.63995 ± 0.00014 days is derived. A dipole magnetic field geometry is found, with Bp = 1300 ± 100 G, beta = 60 ± 5 , and i = 23 ± 11 . Doppler Imaging of the surface distribution of Si, Ti, Cr, and Fe is performed for the primary, and strong inhomogeneities are found. All four maps present similar abundance patterns, with a large spot near the positive magnetic pole.
Implications of these results, particularly with respect to the stage of evolution at which chemical peculiarities arise, are discussed.

abstract: M.Sc.


title: The Effect of Antidepressants on Cardiovascular Morbidity and Mortality: A Population-based Cohort Study

contributor:
Aronson, Kristan J.
Lévesque, Linda E.
Community Health and Epidemiology

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subject:
antidepressants
cardiovascular risk

abstract: Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2007-09-04 14:46:14.571

abstract:
Background:  Antidepressants such as selective serotonin reuptake inhibitors (SSRIs) and venlafaxine have the potential to exert beneficial effects on the heart via serotonin mediated antiplatelet activity.  However, previous evidence regarding the cardiovascular effects of these agents has been conflicting.  There is a need for further investigation into the risks and benefits of these drugs.
Objective:  To assess the risk of acute MI and cardiac death associated the use of various classes of antidepressants, and determine whether this risk is modified by the presence of predisposing factors.
Methods:  We identified a population-based, retrospective cohort study of 71,253 elderly persons initiating treatment with an antidepressant between 1997 and 2004.  The cohort was analyzed using nested case-control approach with each case of acute MI or cardiac death matched with up to 20 controls according to age (±1 year), duration of follow-up, and year of cohort entry.  Rate ratios for acute MI and cardiac death associated with the current use of various antidepressants were estimated using conditional logistic regression and adjusted for potential confounders.
Results:  Compared with the current use of atypical antidepressants, current use of venlafaxine was associated with a significant reduction in the risk of MI and cardiac death (rate ratio [RR] 0.80 [95% CI 0.66 to 0.97]) that was more pronounced in persons with established cardiovascular disease (CVD) (RR 0.65 [CI 0.50 to 0.86]).  We found no clear evidence of a benefit or harm associated with the use of SSRIs (RR 0.92 [CI 0.79 to 1.06]), although there was the suggestion of a clinically important benefit from treatment with SSRIs for individuals who had history of MI (RR 0.68 [CI 0.44 to 1.07]).  No benefit or harm was observed with other classes of antidepressants.
Conclusions:  These results demonstrate a reduced risk for acute MI and cardiac death associated with current use of venlafaxine among elderly persons.  This beneficial effect appears to be more pronounced in those with established cardiovascular disease.  No clear evidence of benefit on CV outcomes was associated with the current use of SSRIs, although results suggest a potential benefit for use in persons with a previous MI.

abstract: M.Sc.