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Tunnel convergence in stress-fractured ground
No full textWhen tunnelling at great depth in hard brittle rock or when mining-induced stresses cause stress-fracturing of brittle rock, the resulting rock fragments cannot fill the original space. As during a rock blast, geometric bulking occurs when brittle rock is fractured, and the volume occupied by fractured rock is much larger. Near underground excavation, this volume increase causes convergences including floor heave because the fractured rock can only move into the excavation. Unfortunately, analytical tools such as the convergence confinement method (CCM) or the ground reaction curve (GRC) do not account for this rock mass bulking action. Similarly, numerical continuum model, while accounting for material dilation, do not account for the unidirectional expansion (bulking) of the fractured rock. The purpose of this thesis is to combine semi-empirical relations of bulking, established based on field measurements and numerical discontinuum models, with the analytical GRC-method and with 2D numerical models (specifically Phase2TM) to provide a means for estimating the impact of bulking on tunnel convergence. The outcome of this thesis therefore is to provide a means of bulking enhance convergence prediction by analytical and numerical solutions. This is presented for circular tunnels, to facilitate use of analytical solutions, in different rock mass types (plastic and brittle) and for various stress states (stress ratio k = 1 and 0.5) as well as for mining conditions with associated stress changes. The examples presented in this thesis demonstrate that rock mass bulking in brittle rock often dominates tunnel convergence. It is also shown that bulking by extension failure primarily affects the shallow radial displacement profile (near the excavation wall) whereas shear-related bulking, if not suppressed by sufficient confinement, causes deeper-seated radial displacements.
The practical implication of this work is that rock support experiences significantly more radial strain and deformation than predicted by conventional analytical and numerical solutions. These models therefore tend to underestimate the straining of installed rock support
Ontario physicians' perceived competency when providing care for individuals with ASD
No full textThe current document is a manuscript-based thesis investigating the overall perceived
knowledge, competency and experiences of Ontario physicians when diagnosing and treating
individuals with Autism Spectrum Disorder (ASD). A growing body of literature has revealed
that physicians often do not feel comfortable providing care for patients with ASD due to lack of
education, training, exposure, and interest working with this population. However, there has been
a recent shift in the literature focusing on identifying factors that enhance the healthcare system
for patients with ASD as well as barriers that physicians encounter when diagnosing and treating
these individuals. Therefore, the first paper included in this thesis is a mixed-methods analysis of
physicians’ perceived knowledge and competency in terms of diagnosis and treatment of ASD.
Despite their high perceived knowledge regarding the diagnosis and treatment of ASD, medical
practitioners expressed their needs for further education and training regarding ASD. The second paper included is also a mixed-methods analysis examining factors that hinder and facilitate
physicians’ abilities to provide appropriate care for individuals with ASD. Descriptive statistics,
paired-samples T-tests, repeated measures ANOVA, and chi-square analyses were used to
analyze the results of a questionnaire and thematic analysis was used to analyze the semistructured
interviews. Recommendations for improving the healthcare and educational systems
as well as implications for enhancing physicians’ knowledge, competency and experiences are
discussed
Differences between Aboriginal and non-Aboriginal women engaged in street prostitution in Sudbury.
No full textThis study identifies differences between Aboriginal and non-Aboriginal women engaged in
street prostitution in Sudbury, Ontario using an Indigenous Research Paradigm. A sample of
twelve women engaged in street prostitution were interviewed using the Prostitution
Questionnaire developed by Dr. Melissa Farley of Prostitution Research & Education.
Additional questions of regional and cultural relevance were added. A comparison group of nine
marginalized women without experience in prostitution was also interviewed with an abbreviated
interview tool. The results indicated that Aboriginal women engaged in street prostitution
differed from non-Aboriginal women in the following areas: stronger desire for the legalization
of prostitution, more experience with discrimination, more physical assaults, higher alcohol
consumption, more criticism from others about alcohol consumption, stronger desire to reduce
alcohol consumption, more prolonged substance use, stronger desire for treatment of substance use, family with residential school experience, more interest in deepening cultural connections,
more active within their faith, greater contact with family and more trusting relationships. Like
Aboriginal women engaged in prostitution, Aboriginal women with hardships differed from non-
Aboriginal women with hardships in their family experience with residential schools, in being
more active within their faith and having greater contact with family. Furthermore, Aboriginal
women with hardships also had more family and friends living in a First Nations community, had
lived in a First Nations community at some point and had more knowledge of Aboriginal
teachings. Additional results outside of identified differences were also included to help define
the local populations. The findings, in relation to Aboriginal women engaged in street
prostitution, are discussed within the context of historical antecedents, community development
and political policies
Exploring for copper–gold deposits with electromagnetic surveys at Opemiska, Canada
No full textFinding and delineating new economic Cu-Au ore zones corresponding to poorly conductive disseminated mineralization and narrow massive chalcopyrite veins in the Chapais-Chibougamau mining district of Québec is a challenging exploration problem. The site of the former Opemiska underground mine was the location for conducting an experimental ground time-domain electromagnetics (EM) survey for mapping the conductivity, the anisotropy of the conductivity and the chargeability estimated from shape reversals. Measurements at fourteen different sites confirmed the variability of the EM response, and the difficulty of relying on a definite EM signature to locate the economic sulfides. The Cu-Au zones showed a variety of EM responses with a maximum conductance of 100 Siemens and 2 ms time constant. The trends, sizes, shapes and conductances of the relatively strong conductors were identified with success and modeled using thin plates in full space. The vein direction in the weakly conductive zones were quantified from the x-component data. In only one instance was a TDEM response associated with mineralization interpreted to be chargeable. Petrophysical measurements and microscopic observations suggest complex interrelations between the amount of ore, the fabric of the rock, texture, porosity, mineralogical associations and impurities. This explains a wide range of bulk conductivity values from ~0.01 S/m to 4000 S/m measured on rock samples, and suggests that chalcopyrite might be a semiconductor at some locations at Opemiska. The magnetic viscosity effects observed at time scales between 0.01 and 10 ms at Opemiska are associated with magnetic grains of variable size in rocks. Recent observations made during a ground time-domain electromagnetic (TDEM) survey at Opemiska are consistent with four aspects of the spatial and amplitude characteristics of a magnetic viscosity response: (1) the ∂Bz/∂ decay rate is roughly proportional to 1/1+ α, where -0.4 < α < 0.4; (2) the anomalies are mainly visible on the z-component when the EM receiver sensor is located inside or just outside the transmitter loop; (3) there is no obvious x- or y-component response; (4) the sites where magnetic viscosity effect are seen in the TDEM data are coincident with an airborne magnetic anomaly. Previous studies have demonstrated that the magnetic viscosity could be caused by (i) fine-grained particles of maghemite or magnetite in the overburden, regolith or soil that were formed through lateritic weathering processes; (ii) volcanic glass shards from tuff containing ~1% by weight magnetite, which occurs as grains ~0.002 to 0.01 μm in size precipitated in a spatially uniform way, or (iii) from Gallionella bacterium that precipitates ferrihydrite that oxidizes to nanocrystalline maghemite aggregates. The sites investigated at Opemiska are outcropping and well exposed with relatively little or no overburden, and are unfavorable to the formation of maghemite; hence, it is assumed that the source of magnetic viscosity seen at Opemiska cannot be the maghemite, or the other aforementioned causes. Hand samples were collected from Opemiska to identify the minerals present. Polished thin sections observed under an optical reflecting microscope identified the accessory minerals magnetite, ilmenite and pyrrhotite, all known for their relatively high magnetic susceptibility. The use of the scanning electron microscope confirmed fine grained magnetite grains as small as 0.667 μm. An electromagnetic induction spectrometer confirmed the viscous nature of the susceptibility of the Opemiska samples. This suggests that magnetic viscosity could originate not only from fine-grained magnetite and maghemite particles located in the weathered regolith, but also from other iron oxides and magnetic minerals embedded in the rock itself
The influence of pH and chemical denaturants on metal binding and structure of anthrax lethal factor
No full textBacillus anthracis is the causative agent of anthrax, and secretes a three-component toxin consisting of protective antigen (PA), edema factor (EF), and lethal factor (LF). LF is a zinc-dependent metallopeptidase responsible for cleaving mitogen-activated protein kinase kinases in the cytosol. To reach the cytosol, LF must be unfolded to pass through the narrow lumen of the PA channel embedded in the endosomal membrane. Whether the metal-binding motif in LF remains intact, and the Zn2+ ion is co-translocated along with the protein is currently unknown. Using a combination of intrinsic tryptophan fluorescence spectroscopy and chelator studies to probe the unfolding and metal status of LF, this study shows that acidification from pH 7 to pH 5 leads a marked destabilization of LF’s native fold, and a significantly increased degree of Zn2+ accessibility (to chelation) and release. Furthermore, red-edge excitation shift studies show that LF still retains a partial fold even when exposed to low pH and high concentrations of denaturants. Taken together, these results provide insights into the structure and metal status of LF under conditions similar to those encountered during translocation in vivo, and they suggest that LF’s Zn2+ ion is likely lost during PA-mediated translocation
The role of attentional resources in facial expression processing among individuals with high trait anxiety: an event-related potential study.
No full textPrevious research highlights a relationship between anxiety and emotional facial expression processing, particularly for fear, but the nature of this relationship remains unclear. The current study aimed to understand a possible underlying factor of this relationship—specifically, the role of attentional resources was explored using event-related potentials (ERPs). Participants (N=67) were asked to identify target happy, fearful or neutral faces in a Rapid Serial Visual Presentation while ERPs and accuracy were recorded. Results suggest that such processing is largely affected by the degree of attentional resources available and by anxiety level, and are in line with the vigilance-avoidance hypothesis. Individuals with high anxiety showed an early perceptual bias to fearful faces followed by later cognitive avoidance, especially when attentional resources were limited. Results are discussed in terms of clinical interventions which might focus particularly on high pressure situations to anticipate and regulate this sensitivity to threat in highly anxious individuals
Stress reappraisal and its effects on emotional bias, state anxiety, social performance and physiological measurements
No full textMany individuals will struggle with performance anxiety throughout their life. Clinical
research has shown that a positive conceptualization of stress and stress arousal (stress
reappraisal) can lead to positive outcomes such as increased cardiac efficiency, higher GRE test
scores and decreased bias towards threat cues as measured by physiological, performance, and
attentional bias measures in a clinical population. Little is known regarding these processes in
non-clinical populations. As such, this study examined the effects of different conceptualizations
of stress (positive, negative, and neutral) on blood pressure (mean arterial pressure), social
performance ratings, and emotional bias via physiological, observational, self-report, and
attentional bias measures within a non-clinical population. In this study, participants who were
instructed to conceptualize stress as positive had significantly lower mean arterial pressure
(MAP) during a stressful task and significantly higher social performance during a social
evaluation task in comparison to participants who were instructed to conceptualize stress as
negative. This research suggests that a positive conceptualization of stress might improve cardiac
function and performance on certain tasks in a non-clinical sample. Implications from this
research suggest that if one who perceives stress and stress arousal as beneficial may experience
an increase in their performance during a social evaluation situation, a decrease in the negative
effects of stress arousal on physiology, and a positive impact on stress arousal responses
Surveilling ‘stigma’: reading mental health literacy as a colonial text
No full textThe recent circulation of ‘mental health literacy’ texts in mainstream North American media conceptualizes ‘mental illness’ in medicalized terms as a response to what is referred to as ‘stigma’. This paper examines the roots of psychiatry in white supremacy to investigate the visualized juxtaposition of a racialized ‘madness’ against a normalized ‘mental illness’. First I explore theoretically the concepts of madness and mental illness, the identity politics of both concepts, and how these are framed and distinguished in dominant discourses. Second, using critical discourse analysis I suggest how Marc Lepine and Vince Li’s acts of violence are attributed to the production of racialized madness in Canadian news media. I then examine how mental illness is normalized in campaign and documentary films. Reading mental health literacy media as a colonial text, this research finds that stigma is framed as a primitive social behaviour in order to reproduce colonial pathologies rooted in psychiatry
Changes in global self-esteem after short‐term sprint Interval training in elite soccer players
Get PDFWe attempt to highlight of the effect of intensive training on global self-esteem (GSE) and relationship between specific self-esteem
and anaerobic performances among the young elite soccer player. Thirty-two healthy, elite soccer men from the same 1st division club
participated in this study (mean (SD) age 21.4 (0.9) years). None of the participants were participating in any other physical activity
except the soccer training and the high-intensity sprint training (HIST). HIST consisted on repeated-sprint exercises performed during
the warm-up period for eight-weeks (3-times a week). Before (T1) and after (T2) the HIST, all participants performed the repeated-sprint
ability test (RSA) which consisted in 7x30-m runs with 30-s of active recovery. During the recovery, a French translated form of the
RES 10 scale was used to determine the Global Self-Esteem (GSE) change for all participants before and after training. We observed
significant (p<0.05) increase of GSE results after training for all participants. In fact, results were increased from 29.81±2.92 in T1 to
32.4±3.00 in T2. Before training and after training, the total sprint time (TT) was positively correlated to GSE (r= 0.64, p<0.01 in T1
and r= 0.66, p<0.01 in T2). In addition, the fastest time (FT) was also positively correlated to GSE before (r= 0.53, p<0.01) and after
training (r= 0.45, p<0.01). Maximum speed sprint workouts are an effective way to improve anaerobic performances in elite soccer. The
Short intense sprint exercise training should be integrated into the training program for development of self-esteem in young soccer
L’analyse des mouvements oculaires lors du jugement de sourires authentiques et de faux sourires chez les enfants
No full textLe but de la présente étude est d’examiner le lien entre le traitement perceptuel et
attentionnel des vrais et des faux sourires et les résultats à la tâche de jugement de
l’authenticité des sourires chez les enfants. Des enfants âgés de 6-7 ans et 9-10 ans sont
exposés à des sourires comprenant les caractéristiques d’une sourire authentique
(Duchenne symétrique) ainsi que des sourires sans l’activation du marqueur de Duchenne
et des sourires asymétriques. Les participants doivent déterminer si le sourire est
vraiment joyeux ou non. Tout comme chez les adultes, les résultats révèlent que les
enfants, peu importe leur groupe d’âge, jugent le sourire Duchenne symétrique plus
joyeux que le sourire asymétrique et le sourire asymétrique plus joyeux que le sourire
non-Duchenne. Les participants donnent également la réponse attendue plus souvent pour
le sourire Duchenne symétrique et le sourire non-Duchenne que pour le sourire
asymétrique. Contrairement aux adultes, on ne peut pas exclure l’hypothèse de limites
attentionnelles-perceptuelles chez les enfants, puisque bien que le jugement chez les
enfants s’apparente à celui des adultes, le traitement perceptuel-attentionnel demeure différent