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Forward modelling and imaging method studies for cross-hole radio imaging (RIM) data.
No full textThe radio imaging method (RIM) is a cross-hole electromagnetic (EM) method which employs radio frequency EM waves to estimate the electric properties between boreholes. RIM is applied in hard rock mining to find and delineate sulfide mineral deposits. A basic and relatively simple method for imaging and interpreting RIM data is the straight-ray method. However, the strengths and weaknesses of the straight-ray method and other more sophisticated methods have not been studied thoroughly.
In the first part this research, I modelled RIM data using a finite element package, Comsol Multiphysics. To validate the Comsol approach, I compared the Comsol model data with the analytical solution of an electric dipole in a homogeneous whole-space model, and some published analytical solutions and numerical solutions of models with conductive objects. The Comsol generated data are consistent with the analytical and the published results.
Secondly, I used Comsol synthetic data to assess the effectiveness of the straight-ray method for interpreting RIM data and to study the characteristics of the radio-frequency EM fields. I studied four sets of models with conductive objects embedded in resistive environments, which resemble ore deposits in mining settings. The experiments show that the characteristics of the EM fields mainly depend on the wavelength. Longer wavelengths are associated with lower frequencies. In this condition, EM induction is strong. Shorter wavelengths are associated with higher frequencies. In this condition, the scattering effects of EM waves dominate. In the radio-frequency range, I concluded that the straight-ray method cannot always provide high quality imaging results for RIM data.
To account for the scattering effects, I adopted the contrast source inversion (CSI) method, which was originally developed for microwave tomography in medical imaging, to invert the RIM data. The CSI method was tested with Comsol synthetic data and field data. The synthetic studies show that the CSI method provides images with more accurate locations and shapes of the conductive objects when compared with the straight-ray method. The case studies show that CSI imaging results are more consistent for data collected at different frequencies and are easier to interpret geologically
The effects of simulated wastewater nutrient amendments on Sphagnum productivity and decomposition within a subarctic ribbed fen1
No full textPeatlands dominate the flat landscape of the Hudson Bay Lowland (HBL). Sphagnum mosses are
the key peat-generating plants allowing for important ecosystem services such as carbon storage,
climate regulation, and water polishing. The HBL is a location for current and proposed
industrial mining development projects, and its peatlands may become increasingly used to
polish treated wastewater from mining camps. This study focuses on biological changes in the
Sphagnum moss community associated with the addition of simulated treated domestic
wastewater to a subarctic ribbed fen (a wetland type commonly found throughout the HBL). We
determined how the nutrient additions affected the productivity, decomposition, and nutrient
ratios, within the ponds and raised peatland ridge components of the ribbed fen. Field experiment
results show between a four to twelvefold increase in productivity rates of the low-lying
Sphagnum rubellum species, and a twofold increase in productivity for the higher hummock or ridge dominating species Sphagnum fuscum in locations closest to the point source of nutrient
effluent. Regions of the experimental ribbed fen greater than 50 m away from the point source
showed little difference in productivity rates, nutrient content, or decomposition rate than the
reference fen levels. No significant changes to the rate of decomposition of Sphagnum were
observed with relation to distance away from point source nutrients as the experimental fen
decomposition rates were comparable to the reference fen rates. A laboratory peat incubation
experiment was conducted to determine how increasing exposure to the wastewater nutrients
would affect Sphagnum decay potentials. Lab results indicate that greater concentrations of
nutrient additions to incubation environments did not significantly increase the amount of CO2 or
CH4 emissions. However, origin of the peat and the species of Sphagnum moss comprising the
peat was found to be important factors contributing to Sphagnum decomposability and greenhouse gas emissions. Peat formed within a nutrient enriched location produced significantly
greater CO2 and CH4 emissions than peat originating from non-fertilized locations, and hollow
dominant Sphagnum species show greater decomposability than hummock forming species. makers and industries will consult these results for mining development projects within the HBL
and elsewhere in subarctic and boreal biomes
Interpretation of post-mortem microbiology cultures: retrospective analysis of children under five years of age from 2011-2015 in Ontario
No full textA retrospective analysis of sudden unexpected child deaths under five years of age was performed at the Ontario Forensic Pathology Service, Ontario, Canada in an attempt to correlate post-mortem microbiological test results to post-mortem macroscopic and microscopic findings. The study focused on a five year period between 2011 and 2015 for a total of 284 cases, of which 180 were of undetermined cause. A spreadsheet was compiled including bacterial and viral findings, autopsy findings, and final diagnosis. All data was extracted from a central computerized pathology database and manually entered into a separate spreadsheet. Microbiological and cause of death data was assigned a presence or absence score in the form of a one or zero. Spearman correlation coefficients were calculated for each potential combination using a correlation matrix. Correlation coefficients above 7.0 and below -7.0 were considered significant. The significance of microbiological specimens in undetermined causes of death was investigated in this study.Submitted in partial fulfilment of the course FORS 4205
Sibling relationships in families of children with autism spectrum disorder, Down syndrome, and fetal alcohol spectrum disorder.
No full textBackground: Studies have shown that it is often a sibling who takes on the support and caregiving role in the life of a person with a developmental disability (DD) when the parent is no longer able to. However, very little research has examined how siblings adapt to their brother or sister with DD, specifically with autism spectrum disorder (ASD), fetal alcohol spectrum disorder (FASD), and Down syndrome (DS). Differences in the behavioural challenges posed by children with ASD, FASD, and DS are critical, and to the extent that those difficulties vary across diagnoses, differences in sibling reactions are possible.
Method: Siblings of children with ASD, FASD, and DS participated in in-depth qualitative interviews employing a basic interpretative approach.
Results: Thematic Analysis was used to analyze interview transcripts and three main themes were identified: Sibling Demands, Positive Transformational Outcomes, and Supports Conclusions: Supports must be tailored to meet the specific needs of siblings of children with different types of disabilities
Geology and genesis of hybridized ultramafic rocks in the black label hybrid zone of the black thor intrusive complex, McFaulds Lake Greenstone Belt, Ontario, Canada
No full textThe ca. 2.7 Ga Black Thor Intrusive Complex (BTIC) is a komatiitic elongate layered
intrusion composed primarily of dunite, lherzolite, olivine websterite, websterite, and chromitite
overlain by lesser gabbro and anorthosite. After emplacement but before complete crystallization,
a Late Websterite Intrusion (LWI) reactivated the feeder conduit and intruded the base and the
core of the BTIC, including the Black Label Chromitite Zone. LWI is a discordant to semiconcordant
intrusion that produced marginal zones of heterogeneous, interfingering hybrid
matrix and clasts defined as the Black Label Hybrid Zone (BLHZ). The clasts range from 1 to
200 cm in size (rarely > 5m), exhibit amoeboidal to subangular shapes, with sharp to diffuse
margins, and varied in compositions from dunite to lherzolite to chromitite. The nature of these
clasts appear to have been controlled by the compositions of the lithologies, the thickness of
layering, the nature of the contacts between layers, and the initial temperatures of the lithologies
being incorporated. There are two types of hybrid groundmass: 1) hybrid harzburgite containing xenocrystic olivine within a websterite, and 2) hybrid chromite harzburgite containing
xenocrystic chromite and olivine within a websterite. Both types of hybrid rocks are
exceptionally well preserved in terms of mineralogy and textures. The genesis of the BLHZ is
extremely complex and involved five interdependent assimilative processes: (1) mechanical
disaggregation of clasts resulting in dispersal of xenocrysts; (2) grain-boundary melting
(clinopyroxene + plagioclase) resulting in selective assimilation via partial melt mixing; (3)
mineral-reaction relation resulting in the dissolution of high-Mg olivine xenocrysts and
subsequent growth of intermediate-Mg hybrid orthopyroxene; (4) Mineral-melt re-equilibration
between entrained chromite and olivine xenocrysts in LWI melt resulting in diffusive chemical
exchange; and (5) complete dissolution of xenocrystic phases very locally formed clast-free rocks of intermediate composition. From map- and core-scale cross-cutting relationships a possible emplacement model can be made: 1) initial emplacement of the BTIC and primary
cumulate layers; 2) LWI reactivation of the BTIC feeder, and the diking/silling, stoping and
partial assimilation of BTIC wall rocks; 3) formation of heterolithic breccias, heterogeneously
hybridized rocks (BLHZ), and associated sulfide mineralization; and 4) local late stage fractional
crystallization of LWI magma. The intrusion of LWI magma into the BLCZ does not appear to
have consumed any of the chromitite, but has locally reduced the grade of the mineralization
through dilution and dispersal. Low-grade patchy disseminated to net-textured Fe-Ni-Cu-(PGE)
sulfide mineralization locally occurs in clast-rich regions of the BLHZ and appears to have been
generated during the hybridization process. This is the first occurrence known to us where
mixing of a magma and cognate xenoliths has led to the formation magmatic sulfides. This style
of mineralization is relatively restricted within the BTIC but is consistent with the limited solubility of S in mafic-ultramafic magmas and the small amounts of magma involved
The effect of experience, personality and learning style on health and safety performance and physiologic responses of miners training in a simulator
No full textThis study examined how learning style, personality type, and experience
level influence the performance and heart rate variability (HRV) (quantified by
LF:HF ratio and RMSSD) of individuals operating NORCAT’s mining simulator. At
Baseline, the twenty participants completed: Kolb’s learning style questionnaire, the
44 item Big Five Inventory Index; and an Operator Experience Questionnaire. After
which, participants were fitted with a Zephyr BioHarness to measure HRV. HRV data
and performance scores (a computer-based evaluation generated from performance
measures taken while the operator is using the simulator) were collected for three
simulator trials: 1) first use of the simulator; 2) at the end of the operator training
program; and 3) post training during a troubleshooting trial where emergency
situations and faults are initiated by the trainer. During the troubleshooting run,
reaction time to each fault was also recorded. Results indicated that the personality
trait: conscientiousness; was associated with improved performance and increased
Root Mean Square of Successive Differences (RMSSD). Moreover, experienced
operators showed higher performance scores later in the training process
Calibration of the PICO-0.1 bubble chamber and development of coated inner vessels for dark matter search
No full textThe detection of dark matter is one of the biggest challenges in modern physics. The PICO
experiment aims for the direct detection of Weakly Interacting Massive Particles (WIMPs) with
bubble chambers.
In this thesis, results from calibrations of the PICO-0.1 test chamber is presented. Calibrations
were performed at the Tandem Van de Graaff facility of the Université de Montréal. Monoenergetic
neutrons were produced from the 51V(p,n)51Cr reaction with a 1.6 MeV proton beam.
Two 3He neutron counters used during calibrations for neutron flux normalization were also
calibrated. This result is contributing in improving Monte Carlo simulations of PICO-0.1.
Finally, preliminary work was done toward the use of new inner vessel materials with coated
surfaces for bubble chambers. A Condensation Bubble Chambers (CBCs) was used as a test-bench.
Progress has been made toward the usability of Poly-methyl-methacrylate vessels, but more work
is needed to solve spontaneous wall nucleation problems
Phytoavailability, mobility, and solid-phase speciation of antimony (Sb) and lead (Pb) in brunisolic soils surrounding a Pb-Zn smelting complex, Trail, British Columbia, Canada
No full textSmelting activities in the Trail, British Columbia region since the late 1890’s has emitted
metal(loid) contamination in the region (Pb, Zn, Cu, As, and Cd). The objective of this study
was to determine the potential availability, mobility and operationally defined speciation of Sb
and Pb in contaminated soils. Total Sb and Pb are strongly enriched in surface horizons in the
profile (maximum of 737 and 26 376 mg kg-1), with concentrations decreasing with depth.
Sequential extractions on soils indicate an enrichment of Sb in the operationally-defined residual
> reducible > oxidizable > easily extractable fractions (< below detection limits), whereas Pb
shows residual > oxidizable > reducible > easily extractable fractions. Electron optical and
microchemical analysis of selected magnetic grains from LFH horizons indicate the
anthropogenically derived Sb- and Pb particles to be present as discrete oxide- and sulfide/sulfate
particles. The mineralogical and morphological nature of Sb- and Pb- particulate matter is
diverse, ranging from angular massive Sn- bearing Sb- Pb oxides, euhedral and subrounded Sboxides,
and Pb-sulfides and sulfates. These results indicate that, although soils are highly
enriched in Sb and Pb relative to soil quality guidelines, minimal biological uptake and mobility
should exist for both elements
Population dynamics of reintroduced elk (Cervus elaphus) in eastern North America
No full textStudies that focus on identifying factors that influence reintroduction success have often taken an
individual population approach; however, investigating multiple populations can provide
additional insight. The overall objective of this research was to emphasize the value of using
within- and among-population approaches to identifying factors that influence the population
dynamics of a reintroduced species. Elk (Cervus elaphus), a species that was extirpated from
eastern North America during the late 1800s, has been reintroduced to portions of its former
range over the past century through several initiatives. Today, there are several established
populations across eastern regions of the USA and Canada, for which extensive monitoring data
are available, creating an opportunity to investigate reintroduction success. I aimed to use these
data to identify factors associated with changes in the survival and population growth rates of 10
reintroduced elk populations across eastern North America. More specifically, I: (1) performed a
literature review detailing the history of elk reintroduction in eastern North America over the
past century, (2) identified factors associated with the variation in population growth rates
(reintroduction success) for 10 reintroduced elk populations using an among-population
approach, (3) identified and assessed how climate affected the population growth rates of 7
reintroduced elk populations, and (4) investigated direct causes of mortality (predation and train
collisions) associated with a single elk population experiencing low population growth.
Although the number of successful elk restoration attempts has increased over the past century,
there has been substantial variation in population growth rates among reintroductions. Major
iv
causes of elk mortality in restored populations differed between the pre- to post-acclimation
phases of reintroduction. Population growth rates were negatively related to the percentage of
coniferous forest within elk population range, suggesting that expansive areas of coniferous
forests in eastern North America may represent sub-optimal elk habitat.
The Burwash elk population in Ontario had low growth rate compared to most other populations
reintroduced into eastern North America. Predation and train collisions were the most important
source of mortality for this population. The number of annual elk-train collisions, as well as their
locations, were monitored and recorded over 14 years. Collision locations were highly sitespecific
and were positively correlated to the proximity of bends in the railway. By relating the
number of annual elk-train collisions to various climate factors, I found that collision rates were
positively related to snow depth. By analyzing field camera data, I found that elk used the
railway mostly during the fall and spring, when elk commonly travel to and from wintering
grounds. However, by examining VHF telemetry locations, I determined that elk were closer to
the railway in winter than in any other season. Railways likely are perceived by elk as easy travel
corridors, especially in the winter, and deep snow might prevent escape from oncoming trains.
Black bear (Ursus americanus) and wolves (Canis lupus) were the major predators of elk in the
Burwash population. White-tailed deer (Odocoileus virginianus), elk (Cervus elaphus), and
moose (Alces alces), were the ungulate prey species available to both predators. To determine if
predators prefer one ungulate species over another, and to identify which predator species is
likely to have a greater impact on elk survival, I investigated predator diets. To compare rates of
v
ungulate use by predators in relation to prey availability, I calculated the relative abundance of
each ungulate species. I found that wolves used juvenile and adult elk as their primary ungulate
prey in greater proportions in comparison to their availability. Bears on the other hand, tended to
use all ungulate species in proportion to their availability.
Climate is well known to affect ungulate population dynamics; however, several factors (e.g.:
density, predator presence), can govern the response. Relating the annual growth rates of 7 elk
populations to various climate factors I found that responses were population specific. Increased
annual snow fall was associated with declines in population growth rates for 2 of the 7
populations assessed and only 1 population responded negatively to increased summer
temperatures. Climate likely interacts with other environmental variables to influence
fluctuations in annual population growth rates which warrants further investigation.
The results of this research will contribute to informed planning of future elk reintroductions and
should support development through improved management. In addition, this research highlights
the importance of using within- and among- populations approaches to investigating factors that
influence elk reintroduction success
Sentiment analysis on Twitter data using machine learning
No full textIn the world of social media people are more responsive towards product or certain events
that are currently occurring. This response given by the user is in form of raw textual data
(Semi Structured Data) in different languages and terms, which contains noise in data as
well as critical information that encourage the analyst to discover knowledge and pattern
from the dataset available. This is useful for decision making and taking strategic decision
for the future market. To discover this unknown information from the linguistic data Natural Language
Processing (NLP) and Data Mining techniques are most focused research terms used for
sentiment analysis. In the derived approach the analysis on Twitter data to detect sentiment
of the people throughout the world using machine learning techniques. Here the data set
available for research is from Twitter for world cup Soccer 2014, held in Brazil. During
this period, many people had given their opinion, emotion and attitude about the game,
promotion, players. By filtering and analyzing the data using natural language processing
techniques, and sentiment polarity has been calculated based on the emotion word detected
in the user tweets. The data set is normalized to be used by machine learning algorithm and
prepared using natural language processing techniques like Word Tokenization, Stemming
and lemmatization, POS (Part of speech) Tagger, NER (Name Entity recognition) and
parser to extract emotions for the textual data from each tweet. This approach is implemented using Python programming language and Natural Language Toolkit (NLTK),
which is openly available for academic as well as for research purpose. Derived algorithm
extracts emotional words using WordNet with its POS (Part-of-Speech) for the word in a
sentence that has a meaning in current context, and is assigned sentiment polarity using
‘SentWordNet’ Dictionary or using lexicon based method. The resultant polarity assigned
is further analyzed using Naïve Bayes and SVM (support vector Machine) machine
learning algorithm and visualized data on WEKA platform. Finally, the goal is to compare
both the results of implementation and prove the best approach for sentiment analysis on
social media for semi structured data