McGill University Thèses et mémoires publiés en 2006

The three studies described in this Doctoral Thesis pertain to the neurotransmitter serotonin, the environmental factor light, and their role in the regulation of human mood as well as behavioural and perceptual aspects of daily social interaction. Participants were healthy at the time of the study but considered at risk for mood disorders in the future. In Study 1, the serotonin system was manipulated by administering tryptophan. This resulted in a decrease in quarrelsome behaviours, an increase in agreeable behaviours, and improved mood. Changes in perceptions of others were also seen. In Study 2, acute tryptophan depletion was used in …  Lire la suite

Natural ecosystems are dynamic and complex, with many being threatened by human activity. However, humans can also be at the root of a solution to this problem by developing ecosystem engineering which can be used to design, construct, modify, upgrade, repair, remediate, and maintain ecosystems. The aim of this project was to improve virtual ecosystems that can be used to increase the knowledge base for ecological engineering by studying adaptability as a factor for the success of species. This was done by analysing adaptive species in a virtual ecosystem, a computer application with which various configurations can be designed and …  Lire la suite

The essence of running an enterprise which is defined as a system by which the companies are lead and compared is generally set in priority terms. For some, they favour in the first instance to secure the economic efficiency then to scope with the social problems at a later stage---'Shareholder model'. Others are inclined to consider that the priority lies into an environmental, sharing and caring society etc.---'Stakeholder model'. Where the evolution of the corporate governance is going to lead to? And how does it affect the directors' responsibility? After a thorough study of its European evolution in particular in …  Lire la suite

The main objective of this project was to investigate and model phosphorus (P) transport in soil column studies. A model named HYDRUS-NICA was developed, by coupling a hydrological and transport model (HYDRUS-1D model) with an aqueous chemical model (non-ideal competitive adsorption - NICA), to improve the predictions of P transport in soil and water. The HYDRUS-NICA model was developed by replacing the non-linear empirical (Freundlich and Langmuir) equations of the HYDRUS-1D model with the NICA model equations. The numerical accuracy of the HYDRUS-NICA model was then evaluated by comparing the relative errors produced by the HYDRUS-NICA and HYDRUS-1D models. The …  Lire la suite

The Canadian language training sector is a booming industry for those interested in capitalizing on the worldwide demand for English, such as private language schools. Thus, this study analyzed the websites of two Montreal-based private language schools to elucidate how these schools use discursive and visual resources to advance their ideology. Defined as a form of social practice (Fairclough, 1992; Pare, 2002), ideology is the way in which the schools are acting discursively in order to serve their for-profit interests. Specifically, the study investigated how both schools manage the tension between their claims to educational legitimacy and their business concerns. …  Lire la suite

Control of Taraxacum officinale (dandelion) and other broadleaf weeds in turfgrass has been readily achieved with phenoxy herbicides, but the herbicide option has been revoked in many regions, necessitating alternative weed control strategies. One biological alternative is Sclerotinia minor, an Ascomycete fungus. The impact of S. minor on broadleaf weed dynamics and biotic interactions were studied in a turfgrass environment. The goal was to maximize effectiveness of a S. minor formulation as a biocontrol of dandelion using an ecological approach. S. minor efficacy was not affected by turf microenvironments and was similarly efficacious with spring or fall application. All accessions …  Lire la suite

Potato is one of the most important crops grown in Canada and all over the world. Late blight caused by P. infestans is one of the major diseases of potato and is mainly managed by fungicides application. The extensive use of fungicides not only causes adverse effects on the environment but also accelerates the development of resistance in this pathogen. Horizontal resistance is considered as the best choice to control P. infestans as it is durable over years. Breeding for durable resistance requires evaluation of hundreds of breeding lines in greenhouses and in the field. This is usually done by …  Lire la suite

Memory is one of the cognitive functions that is most affected in schizophrenia and memory dysfunctions have a major impact on the functioning and quality of life of these patients. Functional brain imaging can help us identify the brain structures that are affected during the performance of a memory task. Identifying these regions can help us identify the specific cognitive processes that are affected in schizophrenia. [...] The identification of selectively intact and deficient processes involved in memory encoding has potential clinical relevance for the development of more focused cognitive remediation strategies.  Lire la suite

A ballot theorem is a theorem that yields information about the conditional probability that a random walk stays above its mean, given its value St after some specified amount of time t. In the first part of this thesis, ballot theorems are proved for all walks whose steps consist of independent, identically distributed random variables that are in the range of attraction of the normal distribution. With a mild assumption on the moments of the steps, the results are strengthened; the latter results are shown to be within a constant factor of optimal when the value of the random walk …  Lire la suite

The blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) signal, the most commonly used imaging technique to identify localized changes in brain activity, has been shown to exhibit certain transient characteristics that are poorly understood by the medical imaging community. This thesis is aimed at investigating the origins of the post-stimulation signal undershoot phenomenon, a prolonged (~30s-1min) drop below baseline of the BOLD signal after the cessation of neuronal stimulation. Three alternate theories exist regarding the physiological changes responsible for the BOLD undershooting. The first theory suggests that prolonged elevation in the cerebral metabolic rate of oxygen (CMRO2) …  Lire la suite

As part of a research program at McGill University, involving the testing of eight full-scale deep beams, this research studies the response of four full-scale deep beams that were designed in accordance with the strut-and-tie model provisions of the CSA Standard A23.3 (2004). All of the deep beams had a centre-to-centre spacing of 2000 mm between the two supports, 1000 mm in height, and 350 mm in thickness. They were simply supported with an application of a single point load at midspan. The total length of the four beams varies depending on the type of anchorage being used. The four …  Lire la suite

This dissertation deals with al-Ḥusayn's uprising and death based on the classical Arabic sources. It is argued that al-Ḥusayn's uprising and opposition to Yazid's caliphate were directly connected to the matter of the caliphate and the caliph's qualifications. He refused to recognize Yazid's caliphate because he considered it as illegitimate due to the fact that Yazid was not qualified to assume such an important office. It is also argued that because of Mu`awiya, who attempted to secure Yazid's succession by forcing all Muslims to pay homage to him, Yazid became caliph. Wanting to remove the real meaning of the caliphate …  Lire la suite

Soy flour was inoculated with Lactobacillus delbrueckii ssp. lattis R0187, and incubated for 8 h, to evaluate the protein hydrolysis and identify peptides generated by this fermentation, and the impact on ACE and trypsin inhibitory activities. Aqueous protein extracts prepared from different fermentation time periods showed a decrease in soluble protein content (from 2.83 to 0.02 mg/mL), while soluble inorganic nitrogen and free amino acid contents increased (from 0.029 to 0.062% w/w, and from 0.75 to 0.90% w/w, respectively). The protein extracts were analyzed by SDS-PAGE; proteolysis was observed after 5 h incubation of inoculated soy flour, suggesting that glycinin, …  Lire la suite

As XML gains popularity as the standard data representation model, there is a need to store, retrieve and update XML data efficiently. McXml is a native XML database system that has been developed at McGill University and represents XML data as trees. McXML supports both read-only queries and six different kinds of update operations. To support concurrent access to documents in the McXML database, we propose a concurrency control protocol called LockX which applies locking to the nodes in the XML tree. LockX maximizes concurrency by considering the semantics of McXML's read and write operations in its design. We evaluate …  Lire la suite

It is a common practice to retrieve code from an outside source, execute it and return the result to the user. During execution secure data can enter the program by user input or access of a data resource. It is important to track the secure data once it enters the program to identify possible information flows to unwanted regions of the code which would permit undesirable data output to a user. Most approaches to restrict information flow in programs have fallen short of providing a practical solution for mainstream programming languages. To address this issue, this thesis presents two context-sensitive …  Lire la suite

In this study, alpha-Galactosidase (alpha-D-galactoside-galactohydrolase, EC 3.2.1.22) has been isolated, purified, and characterized from intracellular fraction of Lactobacillus helveticus ATCC 10797. It was purified by a combination of ammonium sulfate precipitation and fast performance liquid chromatography system using ion exchange and gel-filtration columns. This enzyme was purified to only 9.44 fold over the crude extract with a recovery of 1.8%. The km of 3.83 mM and Vmax of 416.44 mumol/min/mg protein were calculated from PNPG. The molecular mass was estimated to be 188 kDa by gel-filtration, but 90 kDa by SDS-PAGE, indicating two similar molecular weight subunits. The optimum temperature …  Lire la suite

Soybean [Glycine max (L.) Merr.] seeds contain isoflavones that have positive impacts on human health. Field and greenhouse experiments were conducted in Quebec Canada to determine the effects of management and environmental factors [seeding date (late May and mid June), row spacing (20-, 40- and 60-cm), weeds (presence or absence), irrigation levels (low, moderate, and high) and genotypes (Proteina, Orford, and Golden)] and of foliar applications of elicitor compounds (i.e., LCOs, chitosan, and actinomycetes spores), on the isoflavone concentrations of mature soybean seeds, and other important seed characteristics. Our results indicated that environmental and agronomical factors have a great impact …  Lire la suite

Energy modulated electron therapy (EMET) is a promising treatment modality that has the fundamental capabilities to enhance the treatment planning and delivery of superficially located targets. Although it offers advantages over x-ray intensity modulated radiation therapy (IMRT), EMET has not been widely implemented to the same level of accuracy, automation, and clinical routine as its x-ray counterpart. This lack of implementation is attributed to the absence of a remotely automated beam shaping system as well as the deficiency in dosimetric accuracy of clinical electron pencil beam algorithms in the presence of beam modifiers and tissue heterogeneities. In this study, we …  Lire la suite

As people continue to immigrate to Canada, it is becoming more important to consider the many social challenges that migrant youth face upon their arrival. The purpose of this MSW thesis was to evaluate the subjective experience of adolescents in a welcoming class who participated in a video art pilot project. Twelve adolescents were interviewed using a semi-structured qualitative format after the end of the project. They reported enjoying the group work process, discovering each other's talents and learning new skills such as how to use a video camera. All of these responses echo the goals of the Positive Youth …  Lire la suite

NOD.B6 Idd3 congenic mice, whose Idd3 locus originates from the autoimmune resistant C57BL/6 mouse, demonstrate a drastic reduction in diabetes onset. In this study we demonstrate that NOD.B6 Idd3 mice show halted disease progression and also show reduced levels of TH1 cells in their peripheral immune system. In vitro , CD4+ CD25- effector T (TEFF ) cells from congenic mice display increased proliferation and IL-2 production compared to wild type NOD mice. However, unfractionated NOD.B6 Idd3 CD4+ T cells maintain a higher TREG:T EFF ratio and proliferate less than their NOD counterparts, suggesting increased immunoregulation. In vivo, the Idd3 locus …  Lire la suite

Accurate dose calculations and analysis tools are essential to radiotherapy treatment planning. Radiotherapy deliveries utilize the information provided by the treatment planning system and it is generally accepted that clinical outcome can be improved if accuracy in the dose delivery is further improved. Proven Monte Carlo calculations increase the planning accuracy however, most radiotherapy departments do not use Monte Carlo. The McGill Monte Carlo treatment planning system, MMCTP, provides a flexible software environment to integrate Monte Carlo planning with current and new treatment modalities and deliveries. The MMCTP design consists of a graphical user interface, which runs on a simple …  Lire la suite

In his collection of lectures, the Majalis al-Mu'ayyadiyyah, al-Mu'ayyad fi al-Din al-Shirazi's (d.ca. 1078 C.E.) typologies of the imam set forth a distinctive concept of the Isma`ili imam, as it subsequently results from al-Mu'ayyad's engagement in the works of his predecessors and contemporaries in the Isma`ili missionary organization (da`wah). Al-Mu'ayyad's refutations against the "Exaggerators" (Ghulat) and the "Shortcomers" (Muqaṣṣirun) call attention to the importance of walayah as a doctrine of religious authority and guidance in the light of debates concerning the divinity or humanity of the figure of the imam in the mediaeval Shi`i tradition. In his main doctrinal work, …  Lire la suite

Dans son recueil de conférences connu sous le titre de Majalis al-Mu'ayyadiyyah,al-Mu'ayyad fi al-Din al-Shïrâzï (m. ca. 1078 de l'ère commune) établit une typologie de l'imam qui révèle une approche originale à l'imamologie ismaélienne. Cette vision particulière du rôle de l'imam s'explique par la volonté qu'avait al-Mu'ayyad de perfectionner la doctrine de ses prédécesseurs et de ses contemporains actifs au sein de la convocation ismaélienne (da'wah). La critique que fait al-Mu'ayyad des "Maximalistes" (Ghulat) et des "Minimalistes" (Muqassirun) souligne l'importance de la walayah comme doctrine d'autorité et de bonne direction religieuse dans les débats concernant la divinité ou l'humanité de …  Lire la suite

Dans sa théorie du common-link (lien commun), Joseph Schacht soutient que les compilateurs de hadith faisant autorité ont sciemment et délibérément propagé des traditions dont l'excellence des chaînes de transmission pouvait être mise en doute. Ce point de vue a subséquemment trouvé de nombreux adhérents parmi les orientalistes. G. H. A. Juynboll, Michael Cook et d'autres ont épousé les vues de Schacht et ont su en tirer d'autres applications. Dans la présente thèse, nous contestons la justesse de la théorie de Schacht.  Lire la suite

The Common-Link Theory, invented by Joseph Schacht and widely accepted in modern scholarship, argues that ḥadith authorities knowingly and purposefully placed traditions in circulation with little care to support these ḥadiths with satisfactory isnads. G. H. A. Juynboll, Michael Cook and other Schachtians subsequently embraced and elaborated upon this theory. This dissertation challenges the accuracy of Schacht's founding theory. The first chapter traces back and elucidates the formation of Schacht's Common-Link Theory, demonstrating how it is related to his other theories. The second chapter examines the responses to Schacht's theory, arguing that its proponents do no more than either expand …  Lire la suite

Two species of desert truffles, Tirmania and Terfezia were collected from the Northern desert region in Saudi Arabia for antimicrobial and antioxidant activity testing. Both species were extracted with four types of extraction solutions, methanol, ethanol, ethyl acetate and water to test for antimicrobial activity and with three extraction solutions, methanol, ethanol and water for antioxidant activity. Using disc diffusion method, the extracts were subjected to twenty three different microorganisms to observe the antimicrobial activity by measuring clear zones. Methanol extract from Tirmania was the most effective, followed by those extracted with ethanol, water and ethyl acetate respectively. In Terfezia, …  Lire la suite

Purpose. To explore the experiences of healthcare managers at a reformed CSSS (Centres de sante et de services sociaux) in Montreal, Quebec and to document the provincial reforms. The objective is to understand the managers' experiences during a period of transition. Method. This study consists of two methods: a document review of relevant policies and reforms of Quebec's health and social services. Secondly, qualitative interview methods were used to explore the experiences of seven managers within a CSSS and their attitudes towards the reform. Results. Managers described the following: a new window of opportunity, importance of leadership in the reform …  Lire la suite

The goal of this thesis was to move toward defining the molecular mechanism(s) of Vitamin A-induced limb malformations. Vitamin A and its biologically active metabolites, the retinoids, are potent limb teratogens, inducing reductive defects, preceded by decreased chondrogenesis and upregulated apoptosis. To target the origins of these effects, we focused initially on characterizing the pathway of Vitamin A-induced apoptosis. Our first objective was to identify mediators of the degradation and commitment phases of this process. We show dose-dependent activation of the effector caspase, caspase-3, and increased mitochondrial cytochrome-c release after treatment. The next objective was to determine whether these changes …  Lire la suite

Fedor Dostoevskii and Petr Verkhovenskii, the author and one of the main protagonists of the novel Demons, exhibit the same communication style and pursue similar propagandistic purposes in their public communication. Both figures function in the framework of public relations, employing mass communication for the sake of publicizing their political messages to broad audiences. In the process of their public communication, the author and the hero of the novel merge literature and journalism, fictional and factual discourse, subvert a critical analysis of their respective messages and encourage an unconditional, if unwarranted, acceptance of their communication. Relying on the theoretical findings …  Lire la suite

In DC-cast 1xxx-series aluminum alloy ingots, the presence of Fe and Si, and cooling rates increasing from < 1°C/s in the ingot center to ~20°C/s near the surface cause the formation of metastable intermetallic Al6 Fe and AlmFe compounds in addition to the stable Al 3Fe. The highly contrasting etching/anodizing response of the Al 6Fe and AlmFe particles forming in the adjoining central and peripheral regions, respectively, creates the fir-tree zone (FTZ) defect in DC-cast ingots. This, in turn, causes streaking in Al sheets. The need was great for a good fundamental understanding of the mechanism of metastable Al-A1mFe eutectic …  Lire la suite

The purpose of this research is to study the factors influencing the attitude of male academic librarians towards copyright laws in Saudi Arabia. The Tripartite Model is used to evaluate the overall attitude of academic librarians, defined in terms of three main components: feelings, beliefs, and behaviors. Five independent variables that may affect this attitude are investigated: level of education, domain of practice, position, professional experience, and academic librarians’ knowledge of copyright laws as measured by six pre-selected questions (knowledge Index). The knowledge Index is also later measured against the four other independent variables. Seven major universities were chosen, and …  Lire la suite

Oil-bearing plants are important sources of edible oil and proteins; they have attracted attention recently because of their antioxidant, antimicrobial and anti-inflammatory properties. The objective of this work was to investigate the nature of phenolic compounds in oil-bearing plants and the effects of phenolic compounds on protein isolates from soybean and flaxseed. Proteins were isolated from full-fat and defatted soybean and flaxseed using sodium hydroxide extraction and isoelectric precipitation. Free phenolic compounds were extracted from the oil-bearing plants and protein isolates using methanol; for bound phenolic compounds the oil-bearing plants and proteins were subjected to basic and acidic hydrolysis followed …  Lire la suite

Activating mutations in the Fibroblast Growth Factor Receptor-3 gene (FGFR3) cause a number of chondrodysplasia in human, including achondroplasia (ACH) the most common form of inherited dwarfism. Mouse models of achondroplasia have shown that one consequence of inappropriate Fgfr3 activation is a significant reduction in the level of expression of the Indian hedgehog gene (Ihh), encoding a signaling peptide essential for growth plate chondrocyte proliferation and maturation. How FGFR3 signaling controls Ihh transcription is unknown. We used specific small molecule inhibitors of some of the signal transduction pathways known to act downstream of FGF receptors to test the involvement of …  Lire la suite

Through an in-depth study of the Canadian case, this thesis demonstrates how a loss of control over national borders can result from liberal-democratic state efforts to restrict the rights of non-citizens. It argues that the gaps created between certain fundamental due process and equality rights and state control practice increase the risk of policy failure by opening up avenues along which the authority and capacity of the state can be challenged effectively---by encouraging rights-based politics, irregular migration, and administrative inefficiencies. Part I provides an overview of recent international migration trends, followed by a detailed examination of the liberal-democratic control literature, …  Lire la suite

Semiconductor nanocrystals exhibit strongly size-dependent absorption spectra and consequently are of great interest for use in nanoscale devices. As the excited states of these crystals are short-lived, spectroscopic investigation of the nature and size dependence of their energy levels requires femtosecond laser pulses. We have synthesized cadmium selenide nanocrystals and constructed a femtosecond instrument around a commercial laser system from Coherent to study them. The instrument is capable of measuring the autocorrelation and crosscorrelation of laser pulses and can measure the transient absorption dynamics of nanocrystals via pump-probe spectroscopy. A novel means of simultaneously measuring the dynamics associated with two …  Lire la suite

Traditional interpretations of Plato see him either as an enemy of the imagination in his views of philosophic discussion, or as a purveyor of imaginative lies in his authoritarian and anti-democratic view of politics. Instead this thesis challenges both these interpretations by showing how the imagination is both philosophical and democratically political. In the Republic images and stories balance and enrich rational argumentation. I first analyze the imaginary aspects of Plato's ideal city. Secondly, I look more closely to the role of images in education and poetry by focusing on Plato's distinction between good and bad images. Thirdly, I discuss …  Lire la suite

This study investigates individual creative performance in the context of social networks in medium sized work groups (n = 15 - 25) by combining individual, contextual, and social network antecedents. It is an effort to build a balanced model that takes into account the position of the individual within the social system, as well as individual motivation and perceptions of organizational context. The results show that the effects of motivational and contextual factors on creative performance are mediated by creative behavior performed by the individual. The individual's position in the social network and the nature (strong or weak) of the …  Lire la suite

The present work was performed on primary A319.2 alloy to investigate the effect of magnesium and strontium additions on the heat treatment behaviour and mechanical properties of the alloy. Samples were cast in permanent mould, then cut in order to obtain coupons which were solution heat treated at 495°C for 4 and 24 hours, followed by quenching in hot water. Two different artificial aging temperatures were applied at 180°C and 220°C for times from 0.5 h up to 24 hours. The investigation consisted of a systematic measurement of macrohardness and matrix microhardness of samples under different heat treatment conditions. Tensile …  Lire la suite

"No (person) is an island" (Donne J, 1975, p. 87). The importance of social support in the lives of human beings is evident and for immigrant adolescents the role of social networks is important to facilitate their adjustment within the majority culture and to navigate their identity within spaces of belonging. This study aims to describe how Filipino immigrant adolescents in Cote-des-Neiges, a district in Montreal, organize social support and how this relates to their mental health. This research is a mixed design with a sequential strategy. Firstly, data about social support from an epidemiological survey of Filipino youth are …  Lire la suite

This study concerns the concept of sacred architectural imitation, using the Platonic notion of mimesis which then later finds expression in the medieval idea of imitatio. In Religious as well as in artistic and architectural forms of expression, the notion of imitation is indeed a very central and complex issue. At the heart of this concept is the question of meaning, or, more precisely, the transference or translation of meaning; from original to copy, from prototype to reproduction. In order to better illustrate and understand the principles guiding the notion of medieval sacred architectural imitation I have chosen to focus …  Lire la suite

Sleep apnea is a condition where breathing unexpectedly stops during sleep. This condition is a common medical problem affecting infants that can result in serious complications if left untreated. Anesthesia can increase episodes of post-operative sleep apnea in infants. Therefore, the monitoring of infants after surgery is of utmost importance. The standard for diagnosing apnea events remains the visual scoring of cardiorespiratory data by trained personnel. This process is time consuming and prone to human error. In this thesis, we present automated off-line algorithms for the detection of pauses, asynchrony and movement artifact in cardiorespiratory data. These algorithms were implemented …  Lire la suite

This thesis presents a robust programmable analog Gaussian noise generator suitable for mixed-signal test applications. Unlike conventional methods, noise generators employing a linear feedback shift register (LFSR) or resistor thermal noise amplification techniques, the user has full control over the characteristics of the Gaussian signal. Indeed, the frequency band, the mean, and the variance of the distribution are fully programmable over the voltage range within the supply rails. The method consists of digitally encoding the specified Gaussian signal in a random access memory (RAM), using pulse-density modulation, followed by filtering the output bit stream using an analog low-pass filter. It …  Lire la suite

Pax3 is a gene that encodes for a transcription factor involved in embryogenesis. Pax3 heterozygote mutants in mice (Splotch) and humans (Waardenburg Syndrome) exhibit pigmentary disturbances. Also, neural tube defects (spina bifida) develop in homozygous splotch mice. Pax3 has 2 DNA binding domains, a paired Domain (PD), and a paired-type homeodomain (HD). We have used site-specific modification of single Cys Pax3 mutants (in a Cys-less backbone) to probe structure: function relationships. N-Ethyl maleimide (NEM) modification of a single Cys in the PD (C82) abrogates DNA binding by the PD but also by the HD. Likewise, NEM modification of V263C in …  Lire la suite

This thesis describes preliminary research on the application of Markov Decision Processes (MDPs) to the optimisation of mine scheduling in an uncertain environment. The MDP framework is a novel approach to scheduling in a mining operation and option valuation. The task of scheduling in mining operations is dependent on the availability of models that permit the representation of some of the key stochastic properties of the environment, such as grade and price uncertainty. The tools used to model these processes are respectively sequential Gaussian simulation and Geometric Brownian motion. Three cases of increasing size are used to illustrate the results …  Lire la suite

Primary Effusion Lymphoma (PEL) is a lymphoproliferative disease of B cell origin associated with HHV-8 infection and characterized by migration of tumor cells to serous body cavities. PEL cells originate from post-germinal center B cells yet harbor a non-B, non-T phenotype, a characteristic that has not been fully explained. In the present study we demonstrate that PEL cells have an impaired expression of B cell-specific transcription factors and this results in a decreased activity of promoters regulating essential B cell genes. PEL cells lack PU.1 expression, although its transcription partner IRF-4 is highly upregulated, leading to decreased activity of the …  Lire la suite

Gradient-based junctions form key features in such applications as object classification, motion segmentation, and image enhancement. Asymmetric junctions arise from the merging of an odd number of contour end-points such as at a 'Y' junction. Without an asymmetric representation of such a structure, it will be identified in the same category as 'X' junctions. This has severe consequences when distinguishing between features in object classification, discerning occlusion from disocclusion in motion segmentation and in properly modeling smoothing boundaries in image enhancement. Current junction analysis methods include convolution, which applies a mask over a sub-region of the image, and diffusion, which …  Lire la suite

The importance of technology in education cannot be underestimated. There are compelling reasons for developing nations like Pakistan to introduce technology in their educational systems. Nevertheless the approach and methods used in introducing technology in schools are premised on an economic ideology and based on a techno-centric curriculum that leads to new forms of dependency by keeping individuals from controlling the decisions that significantly shape their lives. Introduction of technology does not automatically guarantee enhanced learning or effective teaching. Technology in education should be used as a tool to increase communication, create awareness, break down existing hierarchies, develop new styles …  Lire la suite

The study presented in this dissertation focusses on the analysis of novices' trajectories in learning genres of their profession, engineering. The goals of the study are: (a) to refine the current understanding of what constitutes professional genre knowledge and of how novices learn and use genres of professional communication, and (b) to test the effectiveness of the suggested pedagogy for an Engineering Communication course. This qualitative longitudinal exploration includes ten case studies that span eight years and trace the participants' trajectories through the university and workplaces. I use a combination of three theoretical perspectives---Rhetorical Genre Studies, Activity Theory, and situated …  Lire la suite

A model study for the synthesis of the fungal metabolites phomoidride A and B is presented. Building on previous studies from our group, the carbocyclic core of these molecules was constructed using a [6+4] cycloaddition between tropone 41 and the silyl enol ether of 2-cyclopenten-1-one. Efforts to install the C-17 phomoidride sidechain on substrates derived from this carbocycle met with limited success. This led us to revise our strategy by employing the novel 5-substituted cyclopentadiene 118. In contrast to the known instability of 5 substituted cyclopentadienes towards [1,5] hydrogen shifts, the 2-silyloxy moiety of 118 imparted remarkable thermal stability on …  Lire la suite

A commercial electron dose calculation software (Eclipse TM) implementation based on the Macro Monte Carlo algorithm has been introduced. Eclipse™ initial configurations were performed for all available electron beam energies 6, 9, 12, 16, and 20 MeV. We evaluated the electron Monte Carlo (eMC) module of the Eclipse™ using a verification data set comprised of depth dose curves, profiles, Relative Output Factors (ROF), and 2-0 dose distributions in the transverse plane in a homogeneous phantom. The verification data set was comprised of measurements performed for combinations of 6, 9, 12, 16, and 20 MeV beam energies with five standard field …  Lire la suite