McGill University Thèses et mémoires publiés en 1997

The statistical analysis of brain functional and structural change presents a formidable statistical problem. Computation of a test statistic indicating change at each location of the brain gives a 3-D statistical image. The global maximum of the statistical image has been proposed by Friston et al. (1991) and Worsley et al. (1992) to test for regions of high change based on the belief that the changes are localized, not distributed. To find the correct p value, Worsley et al. (1992) modelled the statistical image as a stationary random field under the null hypothesis. The approximate p value of the global …  Lire la suite

The subject of this thesis is the female characters' way of seeing in the works of Colette. Colette helps liberate women from an oppressive concept of femininity, this being the ultimate goal of the postmodern feminists (Helene Cixous and Luce Irigaray). In Colette's works we find several characteristics that show her resistance to the dominant ideology, the most important being an emphasis placed elsewhere than upon things considered important in patriarchal culture. Renee Nere of La Vagabonde, novelist and music-hall mime, is examined in the second chapter. For Renee, liberty is more important than the security of the established identity …  Lire la suite

Within this thesis, I argue for an interpretive approach to bioethics in pediatric intensive care. I begin by outlining the dominant bioethical doctrine that defines standards for ethical care in critically ill children. I critique this doctrine as legalistic and acultural. Drawing largely on the ideas of Charles Taylor, I call for a reconception of bioethics and propose an interpretive framework that is centred on culture and context. Finally, I illustrate this interpretive approach through a comparative study of two cases in pediatric intensive care: the narratives of Marc and Larry.  Lire la suite

The claim that mentorships are particularly appropriate and in some ways unique educational experiences for high ability students was empirically tested. Students who had and had not taken part in a gifted, creative, or enrichment program (n = 39) completed a questionnaire that consisted of scenarios and statements addressing mentees' vocational and psychosocial needs. Of particular interest were the factor analyses generated from students' responses to the direct statements. As predicted, the high ability group preferred mentorships addressing psychosocial needs to those addressing vocational ones. All five psychosocial items loaded on factor 1, while nine of the 11 vocational items …  Lire la suite

Metabolites of arachidonic acid, known as eicosanoids, result from two enzymatic pathways: cyclooxygenase (COX) and lipoxygenase (LOX). Indomethacin (INDO), at a dose level of approximately 10 mg/kg, has been commonly used in studies on the role of prostagiandins (PG) in the porcine ovulatory process since it was believed to be specific in its inhibition of the COX pathway. Other evidence suggests that INDO also has inhibitory effects on the formation of LOX metabolites including 12- and 15-hydroxyeicosatetraenoic acid (HETE). There is also evidence that LOX metabolites may have a role in the ovulatory process of the rat and the pig. …  Lire la suite

This dissertation examines the emergence of revisionism in the foreign policies of the great powers: it is concerned with the rise of 'challenger' states. Current approaches to the rise of challengers (arguments from 'structure', 'prudence', and 'historical sociology') are if generally useful also incomplete, leaving the emergence of several great power challengers not fully explained. This dissertation offers a new explanation, not as a replacement but as a complement to these theories, and in doing so accomplishes two tasks: first, it explains cases previously unaccounted-for; and second, it does so in a fashion that acknowledges the co-determination of domestic and …  Lire la suite

Plasmodium falciparum is a protozoan parasite and the causative agent of the most lethal form of malaria, a major disease in the tropical world. Chloroquine has been very effective in treatment of this disease, however the emergence of chloroquine-resistant strains in most geographical regions where malaria is endemic has made difficult the control of malaria. In addition, resistance to other antimalarials has been observed in these regions. The objective of this study was to determine the molecular mechanisms of multidrug resistance in P. falciparum. We have selected in vitro a P. falciparum strain resistant to actinomycin D from a parental …  Lire la suite

This thesis considers waveform shaping and error control coding methods to improve the performance and capacity of an asynchronous DS-CDMA communications system. The uplink of the IS-95 cellular CDMA standard is an example of such a system. In this work, we develop a criterion to measure the merits of a waveform shaping filter from the points of view of interference reduction and bandwidth occupancy. This criterion allows us to derive quasi optimal waveforms. It is shown, for example, that the pulse shaping filter of the IS-95 standard is close to optimal. We also show, in the first part of this …  Lire la suite

The magnocellular neurosecretory cells (MNCs) synthesizing and secreting the hormones vasopressin (VP) and oxytocin (OXT) are best known for their direct role in controlling the body fluid homeostasis through changing their firing rates in response to changes in the osmolarity of the extracellular fluid, and subsequent neurohypophysial hormone release. In response to dehydration, MNCs fire clusters of action potentials to maintain sustained high levels of VP to overcome the circulatory failure (Poulain et aL, 1988). Changes in the osmotic pressure have been shown ta be a potent regulater of MNC activity and neurohypophysial hormone release. In addition, recent eleetrophysiological studies …  Lire la suite

Polymer dispersed liquid crystals (PDLC's) are novel composite materials consisting of micron-size liquid crystalline droplets dispersed uniformly in a solid polymer matrix. PDLC's are formed by spinodal decomposition induced by thermal quenching or polymerization. These materials have excellent magneto-optical properties, and have great potential in applications that require efficient light scattering. Present commercial applications include switchable windows for privacy control and large-scale billboards. The optical properties depend on the droplet size, shape and positional order, which are determined during the formation stage, and reorientation dynamics of the liquid crystalline molecules confined within the droplets which occurs during product use. In …  Lire la suite

Reactive amyloidosis characterized by the tissue deposition of insoluble AA amyloid (AA), is a potentially serious complication of certain chronic infections and recurrent inflammatory diseases. AA is derived from the amyloidogenic serum amyloid A (SAA), an acute phase protein whose plasma concentration may increase up to 1000-fold in response to tissue trauma. Chronic elevation of SAA in conjugation with inflammation-related host factors is believed to induce conversion of SAA to AA. One such host factor, called amyloid enhancing factor (AEF), has recently been identified as ubiquitin (UB). However, the molecular pathogenesis of AA amyloidosis in vivo is not well understood. …  Lire la suite

A thickness-shear mode (TSM) acoustic wave sensor system has been constructed and used to examine binding phenomena that occur in the liquid phase. The work is broadly divided into two sections. The first section examines the use of cholestyramine as a sensor coating for detection of bile acids. A 10-MHz piezoelectric crystal is coated on one side with cholestyramine resin and mounted in a batch-mode sensor block which exposes the coating to solution. After sample injection, the binding process is observed in real time as a drop in frequency as the bile salt binds to the coating, reaching >90% completion …  Lire la suite

This thesis examines the use of orality as a means to self-definition in Anne Rice's Vampire Chronicles. The main contention of this thesis is that within the Vampire Chronicles orality defines the self through incorporation, and that the bodily incorporation of food through a sexual consumption leads the vampire to naturally evolve a sense of who he or she is at any given moment in time. It is in this manner that this article discusses how the body, sexuality, food, and the possession of financial capital define and limit the individual's notion of self.  Lire la suite

Inhibition of HIV-1 replication by insulin, albeit at supraphysiological concentrations (10$ sp{-7}$ M) has previously been shown. The fact that this effect could only be seen at such high concentrations indicated that insulin might be acting via the IGF-1 receptor, which it may bind at highly elevated concentrations, but with much less affinity. We now show that IGF-1 can effectively inhibit HIV-1 replication in chronically infected U937 cells at concentrations similar to normal physiological concentrations. We have demonstrated that this inhibitory effect may be abrogated by the presence of anti-alpha-IR3 and anti-IGF-1 antibodies, directed towards the IGF-1 receptor and the …  Lire la suite

Matrix factorizations are among the most important and basic tools in numerical linear algebra. Perturbation analyses of matrix factorizations are not only important in their own right, but also useful in many applications, e.g. in estimation, control and statistics. The aim of such analyses is to show what effects changes in the data will have on the factors. This thesis is concerned with developing new general purpose perturbation analyses, and applying them to the Cholesky, QR and LU factorizations, and the Cholesky downdating problem. We develop a new approach, the so called 'matrix-vector equation' approach, to obtain sharp results and …  Lire la suite

A quantitative research synthesis (meta-analysis) was conducted to determine the effects of exercise on health-related physical fitness of people with an intellectual disability. While studies on this topic have been qualitatively reviewed (e.g., Fernhall, 1993; Fernhall, Tymeson, & Webster, 1988; Pitetti, Rimmeri & Fernhall, 1993), the effects of exercise on some of the health-related physical fitness components remains unclear, or unknown. Further, none of the reviews determined the influence of study characteristics on study outcomes. The data were 24 studies yielding 104 effect sizes based on 826 subjects. These analyses revealed that the outcomes of the studies related to cardiovascular …  Lire la suite

This study examined whether movements of fishes across reserve boundaries reduced the difference in density and size of fish between reserve and non-reserve areas. Visual censuses, experimental trapping, habitat measurements and tagging were performed at 10 sites on two nearly contiguous fringing coral reefs at the northern edge of the Barbados Marine Reserve and at 10 sites on the two fringing reefs closest to the boundary in the non-reserve. The visual censuses showed that overall density and size of fishes large enough to be caught in Antillean fish traps were higher on reserve reefs than on non-reserve reefs. The differences …  Lire la suite

Since Homer, exile is closely linked to literature and even seems to be consubstancial to the very act of writing. Indeed, countless writers have created in exsilio; one just has to think, among others, of Marot, Du Bellay, Madame de Stael, Victor Hugo or Soljenitsyne. The unbearable feeling of loss and relinquishment provoked by transhumance added to the inevitable solitude are determining factors leading to the creative process. Neo-Quebecois writers are undoubtedly part of this line of expatriate authors. Often autobiographical in nature, their work generally describe the migratory journey of misfits trying to make Quebec culture their own. However, …  Lire la suite

The taxonomy of this genus is studied, three species of Eurycantha were chosen, E. horrida, E. coriacea and E. calcarata from which two subspecies were collected, termed and identified by the Phasmid Study Group: PSG 23 and PSG 44. Morphological characters and morphometrical data of the adults of E. calcarata PSG 23 and E. horrida as well as data on the ultrastructure and morphometrics of the eggs of all aforementioned species were obtained from this study to show differences and similarities between species and subspecies; partial 16S gene rRNA sequence was used to show genetic relationships between the species. Similarities …  Lire la suite

This thesis is a study of language use and language socialization practices in Northern Quebec. The focus is on families with children between 9 and 24 months of age, particularly bilingual families, living in predominantly Inuit communities. Interviews with 11 families were examined to determine the major issues concerning language use, beliefs, and relationships. Two bilingual families were then examined in-depth over one year to gain a clearer understanding of their language behaviours and how they related to the cultures present in the homes and communities. Results of the study indicate that there is variation across bilingual families in many …  Lire la suite

Weber, M. E. (Advisor)  Lire la suite

The regional lymph nodes are frequently the first site to be invaded by disseminating cancer cells and the extent of lymph node involvement is an important determinant of prognosis and treatment for the most common carcinomas. To study the possible role of the lymph node stroma in regulating the growth of breast cancer cells, rat peripheral lymph node stromal cells (STC) were isolated and their interaction with rat and human breast carcinoma cells was investigated. Initially we found that media conditioned by STC was mitogenic for human and rat breast cancer cells and this effect could be enhanced in the …  Lire la suite

Several multilevel converter topologies have stimulated widespread interests amongst researchers because they have the capabilities of (i) reaching high voltage ratings without magnetics and transformers and (ii) attaining low Total Harmonic Distortions (THD), using the low switching frequencies of gate-turn-off thyristors (GTOS). This thesis focuses on the diode-clamped multilevel converter topology as the basic module for realizing the high kV voltage rating and the high MVA rating in controllers for the Flexible AC Transmission Systems (FACTS). The thesis has extended the topology configurations to include: (i) multiple modules of multilevel converters and (ii) multimodules of multilevel converters in a back-to-back …  Lire la suite

This thesis evaluates the suitability of Thorium(Th) ions for optical spectroscopic measurements in a Paul trap. A $ sp{232}Th$ sample, placed near the ring electrode, is evaporated with a Nd:YAG laser pulse and then selectively ionized by a synchronized dye laser pulse. Ions created inside the trap follow stable orbits and are cooled by hydrogen buffer gas. The stability and trapping efficiency for the ions are examined at various trap operating conditions. The motion of the ions in the trap is studied with particular attention to volume occupied by the ions in the phase space. With the trap operating at …  Lire la suite

The receptiveness of the brain to monocyte infiltration was studied in rats that had been injected intracerebrally with Corynebacterium parvum. 0--17 days after intracerebral injection and 18 hours after intravenous injection of diI-labelled isogenous mononuclear cells, host rats were sacrificed and cells from the vicinity of the injection site and from the contralateral cerebral hemisphere were dissociated and analyzed by flow cytometry. In rats sacrificed 4--11 days post injection, diI-labelled mononuclear cells were detected in cell preparations from the hemisphere ipsilateral and, to a lesser extent, contralateral to the injection site. No extravasation of cells from the blood to the …  Lire la suite

This thesis describes the design and implementation of a real-time system for tracking moving people in an indoor environment. The system utilizes a stationary camera which can be mounted in any location within the indoor environment such as on a wall or the ceiling. Embodied in the system is a control mechanism which is based on a biological model of gaze control. This mechanism controls the movements of software windows which are used for tracking, such that the target is always centred within a window, in much the same way as human eyes move such that a target is always …  Lire la suite

This study examines the debates which marked the entry of culture as a theoretical issue in French architectural writing at the end of the 17th century. The premise is that while culture could he said to have always been present in the very earliest treatises as the context? goal, and medium of architectural speculation, the focus on culture for considering the grounds, principles. and aims of architectural work portends a modern struggle to define a secular basis for human work.. The study begins with Claude Perrault's controversial declaration of arbitrary and positive beauty in the 17th century. Key to this …  Lire la suite

New treatments such as functional electrical stimulation (FES) have been developed that allow people with spinal cord injury (SCI) the ability to stand and walk. This study investigated the use of FES-assisted gait training for two subjects with incomplete spinal cord injury in a single subject, repeated measures A-B design. Average walking velocity, cadence and stride length were determined while walking with and without FES at baseline and post-treatment evaluations. Changes in parameters were analyzed statistically and explained in biomechanical terms. FES-assisted gait training affected modifications in the gait parameters. One subject, initially a non-reciprocal walker, was able to walk …  Lire la suite

Strain and temperature gradients are developed through the cross-section during the hot rolling of steel rods. These gradients are of particular interest because of their potential effects on the homogeneity of the resulting microstructure during rolling as well as in the final product. Strain and temperature can strongly influence recrystallization and transformation behaviour. A three-dimensional, temperature-dependent viscoplastic finite element analysis was used to predict the strain distribution developed for the hot rolling of steel square billets using the software package ABAQUS/EXPLICIT$ sp{ rm TM}.$ Constitutive parameters were determined from previous experimental data generated at McGill University and at the Metals …  Lire la suite

The goal of this research was to investigate the knowledge high school students acquire from science instruction in Zimbabwe, and their ability to reason from and apply their knowledge based on previous learning. Science educators in Zimbabwe are concerned with improving the quality of student's achievement and that students develop a conceptual understanding of basic science rather than a rote memorisation of facts and that students become better prepared to acquire science content on their own. The research reported here utilises the discourse comprehension analysis model and methods developed by Frederiksen (1975, 1986) to investigate students' learning. Based on these …  Lire la suite

Renin is an aspartyl protease that plays a critical role in the production of angiotensin peptides and therefore in the modulation of blood pressure. Renin participates not only in the circulating renin-angiotensin system (RAS) but may also be taken up by tissues to control the activity of the local RAS. In this study, we provide evidence for the existence of a high affinity, saturable binding site for human renin (estimated k$ sb{ rm d}$ of 125 pM) and prorenin, the inactive precursor of renin, in the human placenta. The interesting finding that prorenin could bind to the same site as …  Lire la suite

Observations show the presence of localized regions in the atmosphere with diminished potential vorticity gradients, like in the tropical upper troposphere where outflow from deep convective regions plays an important role. The present work investigates the effect of forcing on the evolution of Rossby waves in a zero potential vorticity gradient environment. As a preliminary investigation, the barotropic case is studied, where the analogue of potential vorticity is absolute vorticity. The analytic solution of the linearized problem shows that the streamfunction grows algebraically in time, and eventually develops a nonlinear critical layer. The numerical solution of the nonlinear problem within …  Lire la suite

The combined effect of films of various gas barrier properties, various gas packaging atmospheres (air, vacuum and gas packaging, oxygen absorbents) and storage temperatures (4 and 12$ sp circ$C) were investigated on the color stability and shelf-life of fresh beef. Meat color was described by reflectance measurements and by reading the color coordinates L* (lightness), a* (redness), b* (yellowness), C* (chroma) and h (hue angle) in the CIE-LAB system. All packaged beef was regarded as unacceptable when reflectance differences values at 630 and 580 nm i.e., due to oxymyoglobin (MbO$ sb2)$ were $ sim$30-35. Based on these standards, aerobic packaging …  Lire la suite

The current study was designed to examine sex differences in the stability of same-sex friendships. Based on past research, it was hypothesized that boys have more stable friendship nominations than girls. Four hundred fifty-one elementary and high school students from grades three, four, seven and eight completed questionnaires in which they were asked to nominate their closest friends. Friendship nominations were collected three times over a seventh month period, in the fall, winter and spring of the school year. Partial support was obtained for the hypothesis at the high school level: Adolescent boys had more stable friendship nominations than adolescent …  Lire la suite

It is inevitable that works on waqf written in English will employ terms from Anglo-American law to describe that institution. This study will endeavour to provide a proper understanding of these terms in order to clear up longstanding misconceptions of the nature of waqf. Through a detailed history of the Anglo-American law of endowments and its terminology, this study will create a framework through which it may be possible to obtain a clearer understanding of waqf. The study will also address two historical events in which the Islamic and Anglo-American legal conceptions of endowments have been at odds, as well …  Lire la suite

Vanadium is a trace element found in most living systems. It has various biological properties. In the last 10 years numerous reports showed that Vanadium administered orally could improve the metabolic state of diabetic animals. The combination of vanadate and H$ sb2$O$ sb2$ produced the new agents called peroxoVanadium (pV) compounds which exerted more potent insulin mimetic effects by activating the insulin receptor kinase. Their application in the treatment of diabetes could be of great benefit clinically in the future. We demonstrated that long-term oral bpV (phen) (a new pV compound) treatment resulted in a lowering of blood glucose levels, …  Lire la suite

Apoptosis has been proposed as the mechanism of neuronal cell death, while altered levels of amyloid precursor protein (APP) and the amyloid beta peptide, a proteolytic cleavage product of APP, are believed to contribute to the neurodegeneration in AD. Thus, defining the molecular mechanisms regulating these events are of interest. The expression of the immediate early genes (IEG), in particular c-jun, has been shown to be a requirement for neuronal apoptosis. Due to the presence of activator protein-1 (AP-1) consensus sequences in the promoter of the APP gene, which has been shown to be responsive to regulation by immediate early …  Lire la suite

Serotonin (5-hydroxytryptamine, 5-HT) is known to influence cerebrovascular functions such as local cerebral blood flow (CBF) and blood brain barrier (BBB) permeability, and has been implicated in cerebrovascular diseases. The present study used a multifaceted approach to determine the distribution, density and origin of the 5-HT innervation of blood vessels at the base of the brain and overlying the cerebral cortex as well as those embedded in the cortical parenchyma. In addition, the type(s) of 5-HT receptor(s) present on intracortical blood vessels as well as their precise cellular localization within the vessel wall was investigated. Firstly, in extracerebral blood vessels, …  Lire la suite

Previous research in cross-language speech perception has shown that English-learning infants at 6--8 months of age and younger can discriminate both native and non-native consonant contrasts. However, by 10--12 months of age, infants' discrimination performance becomes more like that of adults in that they show difficulty discriminating non-native, but not native phonetic contrasts. In the present study, infants (6- to 8- and 10- to 12-months-old) and adults from two language environments (French and English) were compared on their perception of two English stop-fricative contrasts, /b - v/ and /d - th /. The present findings show trends that replicate patterns …  Lire la suite

This qualitative study investigated how a selected group of post-secondary, second language students (L2) students perceive coherence in their written discourse in various disciplinary contexts in a French CEGEP. The primary focus is on the verbal language, or meta-language, derived from participant interviews that students used to describe their written texts. M. A. K. Halliday's (1978) social theory of language, and L. S. Vygotsky's (1962) sociopsychological theories of language provided a framework for conceptualizing the amount of control, self regulation, that students perceive they had in constructing coherent written discourse. Results from the study indicate that although students may have …  Lire la suite

This thesis examines the fundamental relationship between a continuous-time system and its discrete-time models. This involves a study of the conditions that the state space realization of a model must satisfy in order to be valid. While such a study has been performed for models whose order equals that of the continuous-time system, this thesis also includes "higher order discrete-time models", that is, models whose order is higher than the continuous-time system. A strict mathematical definition for models is presented based upon the convergence in a certain sense of the time responses of the continuous-time system and its model. Theorems …  Lire la suite

The remarkable challenges Finnegans Wake offers to its readers and to the very process of reading are the results of an evolution of Nonsense literature. Despite the unduly "serious" framework of criticism which has been built up around it, Joyce's anomalous last work is a radical "hoax" upon interpretation. The regular confluences of linguistic deconstruction (via word association as well as recurring word and phrase matrices) and ontological metaphor, developed from authors such as Rabelais, Sterne, and Lewis Carroll, are offered by the Wake as tests to the reader's (qua reader) sensibilities. As Nonsense, Finnegans Wake departs from typified modernist …  Lire la suite

There are two main components to the research: the theoretical and the experimental. Chapter 2 contains an analysis of the state of soil quality guidelines and the scientific methods used to determine them. A number of recommendations to improve soil quality criteria for trace metals are offered including the importance of considering bioavailability and the need to use realistic conditions, trace metal sources and organisms. A critical review of the literature dealing with predicting the availability of trace metals to plants is presented in Chapter 3. We found little agreement among hundreds of similar studies which relate plant metal uptake …  Lire la suite

The objective of this thesis was to determine, by means of discrete element simulations of ice floes, information that could be used for continuum modelling of broken ice covers on waterways. The ice floes or 'particles' were modelled as random-sized circular disks. The internal angles of friction for cohesionless assemblies of particles under compression were determined using molecular dynamics type simulations of biaxial tests. Constant confining pressures as well as constant displacement rates were used for the biaxial tests. Stress-strain curves were obtained for a range of confining pressures. The yield envelopes were found to be represented by a Mohr-Coulomb …  Lire la suite

Soil and aquatic ecosystems are constantly being exposed to chemical contaminants from industrial, agricultural, and municipal sources. For example, pesticides and herbicides are used on a world-wide scale to control a wide variety of harmful insects and competing weeds, to increase the production of food and fiber, and to facilitate modern agricultural production methods. Although these chemicals are designed to be selectively toxic towards target organisms, this is not absolute, and in most cases pesticides and herbicides are toxic toward non-target organisms, including humans. To identify genes which are transcriptionally regulated by cellular exposure to environmental pollutants, such as pesticides …  Lire la suite

In this work, a physical model describing the electric arc attachment on electron emitting non-refractory (cold) cathodes is developed and applied to Cu, Fe and Ti cathodes. The model considers the possibility of a pressure build up in the cathode region due to the strong vaporization of the cathode, the formation of a cathode sheath according to the Bohm's model, and the ion-enhanced thermo-field emission of electrons by the cathode surface. The self-sustaining operating conditions of the discharge are defined by two simple criteria based on particle and energy balance considerations. Results clearly show the necessity of having high local …  Lire la suite

In his literary work, Honore de Balzac sporadically denounces economic crimes, which, cleverly committed, may wind easily round the law. But it is mainly in his enigma novels that this denunciation becomes more forceful. From the narrators' perspective, fraud and assassination have enriched the Camps (Madame Firmiani) and Lanty (Sarrasine ) families, as well as the bankers---Taillefer (L'Auberge rouge) and Nucingen (La Maison Nucingen). Legal criminality, an eminently serious theme of Balzac's critical realism, is narrated by way of enigma games and their everlasting companion, mystification. A better grasp of the plot's central role leads the reader to discover legal …  Lire la suite

This research examined how song is used to transmit information on individual identity in American redstarts (Setophaga ruticilla). Specifically, it attempted to determine whether American redstarts (1) discriminate between neighbors and strangers on the basis of their respective songs, and (2) recognize individuals by their distinctive voice characteristics. I tested the latter by exposing subjects to identical song types sung by different birds. Each subject's behavior was evaluated according to a variety of response variables. In all trials, for all response variables, subjects responded highly but equally to each of the songs played. A post-hoc analysis revealed that the order …  Lire la suite

A method for estimating long-term average annual soil loss under different land management scenarios from the Marquis and Soufriere watersheds on St. Lucia is presented. The Revised Universal Soil Loss Equation (RUSLE) was used, and a GIS was employed to generate the required input parameters. Model execution and results were also generated within the GIS. Modelling soil loss for the different land management scenarios was based upon a land capability classification and associated conservation treatments. Soil losses under current agricultural land-use patterns were analyzed and compared to potential soil losses under conservation treatments following the criteria specified in the land …  Lire la suite

This study investigated differences among student writers at three grade levels (i.e., 6, 8, and 10), and between expert writers and students, in terms of (a) the extent to which argument structures were used in their persuasive texts, (b) the complexity of these argument structures (as measured by depth and elaboration), and (c) the use of general semantic structures and conjunctive ties to represent argument substructures. In addition, the study determined the predictive relationship between the holistic scores assigned to student texts and argument structure measures. To identify and analyze argument structure a model was developed that could account for …  Lire la suite