An Ecosystem Approach to Antimicrobial Stewardship: An Ecuadorian-Canadian Collaboration To Design, Implement and Evaluate a Community-Based Intervention

English

El Estribo Volcanic Complex: Evolution from a shield volcano to a cinder cone, Pátzcuaro Lake, Michoacán, México

El Estribo Volcanic Complex (EVC) is located in the northern part of the Michoacán–Guanajuato Volcanic Field within the Trans-Mexican Volcanic Belt (TMVB). El Estribo is located at the southern edge of the E-W Pátzcuaro fault that belongs to the Pátzcuaro-Jarácuaro graben, a western extension of the E-W Morelia–Acambay fault system. Stratigraphy, geochronology, chemistry, and mineral assemblages suggest that the volcanic complex was constructed in two periods separated by a ~ 100 ka volcanic hiatus: a) emission of lava flows that constructed a shield volcano between 126 ka, and b) mixed phreatomagmatic to Strombolian activity that formed a cinder cone ~ 28 ka. The magmas that fed these monogenetic volcanoes were able to use the same feeding system. The cinder cone itself was constructed by Strombolian fallouts and remobilized scoria beds, followed by an erosion period, and by a mixed phreatomagmatic to magmatic phase (Strombolian fallouts ending with lava flows). Soft-sedimentary deformation of beds and impact sags, cross-bedding, as well as pitting and hydrothermal cracks found in particles support the phreatomagmatic phase. The erupted magmas through time ejected basaltic andesitic lava flows (56.21–58.88% SiO2) that built the shield volcano and then basaltic andesitic scoria (57.65–59.05% SiO2) that constructed the cinder cone. Although they used the same feeding system, the geochemical data and the mineral chemistry of the magmas indicate that the shield volcano and the cinder cone were fed by different magma batches erupted thousands of years apart. Therefore, the location of El Estribo Volcanic Complex along an E-W fault that has generated two sector collapses of the shield volcano to the north may be directly linked to this complex redistribution of the magmatic paths to the surface. Our findings show that magmatic feeding systems within monogenetic volcanic fields could be long lived, questioning the classic view of the monogenetic nature of their volcanoes and yielding information about the potential volcanic risk of these settings, usually considered risk-free.

IMPACTS OF ENHANCED TEMPERATURE AND SNOW DEPOSITION ON SENESCENCE DATE, VEGETATION COVER, AND CO2 EXCHANGE IN A CANADIAN HIGH ARCTIC MESIC ECOSYSTEM

Arctic regions are expected to experience an increase in both temperature and precipitation over the coming decades, which is likely to impact vegetation dynamics and greenhouse gas exchange. To test this response, an experiment was installed at the Cape Bounty Arctic Watershed Observatory, on Melville Island, NU, in 2008 as part of the International Tundra Experiment (ITEX). Snow fences and open top chambers (OTCs) were used to manipulate snow depth and air temperature, respectively. Unlike most ITEX sites to date, enhanced temperature and snowfall were combined here in a factorial design with eight replicates. As an added control, four plots were established well outside the enhanced snow area. Senescence date was recorded at the end of the season, and at the peak of the growing season a vegetation survey was conducted within each plot in order to determine the total percent cover of each plot, as well as the percent cover of individual species. Carbon dioxide (CO2) exchange was also measured within each plot throughout the growing season. The date of senescence occurred significantly earlier in plots which had not been manipulated in any way, compared to all other treatments for all species. Salix arctica showed the greatest increase in cover over time at the species level. Lichen cover increased significantly in the deepened snow plots, and in general there were significant increases in percent cover in some functional groups over time. During June and into July the net CO2 flux was to the atmosphere. It was not until July 27 that these ecosystems became net carbon sinks. However, warming alone resulted in the ecosystem acting as a significant net carbon sink for the entire growing season. Plots exposed to warming alone were estimated to have removed approximately 19.94 g C m-2 from the atmosphere, whereas all other treatments were very similar to one another and estimated to have added approximately 3.12 g C m-2 to the atmosphere. Active layer depth and soil temperatures suggest that plots within the ambient snow zone may be receiving some additional snow due to their proximity to the fences. CO2 fluxes measured within the outer control plots suggest that the effect of warming alone could lead to this ecosystem being an even stronger net C sink under truly ambient snow conditions.

The Impact of Community Social Capital on the occurrence of Injuries in adolescents and falls in older adults: Population-based Studies Conducted in Canadian samples

The objectives of this thesis were to study specific Canadian populations in order to examine; (1) relationships between the neighbourhood-level social capital and injuries in youth, as well as (2) falls in older adults, and; (3) to address methodological issues relevant to the study of such relationships. The thesis is comprised of four manuscripts. The first addresses methodological issues surrounding the validation of neighbourhood-level variables for the study of adolescent health, and demonstrates the existence of structural confounding in the study of related etiological relationships. Informed by the latter, the second manuscript examines the association between neighbourhood-level social capital and injuries in youth, and demonstrates that lower levels of social capital are protective factors for girls but not for boys. Manuscript 3 uses an international database focused on older adults, and shows that our existing measure of social capital is valid at neighbourhood levels, but also that there is a high possibility for the existence of structural confounding among Canadian older adults. The fourth manuscript then examines the association between neighbourhood-level social capital and the occurrence of falls in older adults and determines that differences between neighbourhoods are important factors in the occurrence of falls, and that higher levels of social capital are a risk factor for falls. Taken together, results from this thesis provide a better understanding of the role of neighbourhood-level social capital on the occurrence of injuries in Canadian youth and on the occurrence of falls in older adults. Our contributions were important both methodologically and etiologically.

Landscape Patterns of Permafrost Disturbance and Degradation in the Canadian High Arctic

Intensification of permafrost disturbances such as active layer detachments (ALDs) and retrogressive thaw slumps (RTS) have been observed across the circumpolar Arctic. These features are indicators of unstable conditions stemming from recent climate warming and permafrost degradation. In order to understand the processes interacting to give rise to these features, a multidisciplinary approach is required; i.e., interactions between geomorphology, hydrology, vegetation and ground thermal conditions. The goal of this research is to detect and map permafrost disturbance, predict landscape controls over disturbance and determine approaches for monitoring disturbance, all with the goal of contributing to the mitigation of permafrost hazards. Permafrost disturbance inventories were created by applying semi-automatic change detection techniques to IKONOS satellite imagery collected at the Cape Bounty Arctic Watershed Observatory (CBAWO). These methods provide a means to estimate the spatial distribution of permafrost disturbances for a given area for use as an input in susceptibility modelling. Permafrost disturbance susceptibility models were then developed using generalized additive and generalized linear models (GAM, GLM) fitted to disturbed and undisturbed locations and relevant GIS-derived predictor variables (slope, potential solar radiation, elevation). These models successfully delineated areas across the landscape that were susceptible to disturbances locally and regionally when transferred to an independent validation location. Permafrost disturbance susceptibility models are a first-order assessment of landscape susceptibility and are promising for designing land management strategies for remote permafrost regions. Additionally, geomorphic patterns associated with higher susceptibility provide important knowledge about processes associated with the initiation of disturbances. Permafrost degradation was analyzed at the CBAWO using differential interferometric synthetic aperture radar (DInSAR). Active-layer dynamics were interpreted using inter-seasonal and intra-seasonal displacement measurements and highlight the importance of hydroclimatic factors on active layer change. Collectively, these research approaches contribute to permafrost monitoring and the assessment of landscape-scale vulnerability in order to develop permafrost disturbance mitigation strategies.

CLASHES IN CONFINEMENT: MEN’S GENDERED EXPERIENCES WITH CONFLICT IN CANADIAN PRISONS

This dissertation presents the results of in-depth qualitative interviews with twenty-three formerly imprisoned men regarding their lived experience with prison conflict and the pain of incarceration. The results suggest that prison is a gendered ‘total institution’ (Goffman 1961). The pains that men experience in prison are uniquely gendered in that the deprivations imposed by incarceration– deprivation of autonomy, liberty, goods and services, heterosexual sex, and security (Sykes 1958) – in the reverse, define idealized masculinity as it is currently socially constructed: self-reliance, independence, toughness or invulnerability, material and economic success, and heterosexual prowess. From these shared deprivations emerges a gendered code of conduct that perpetuates a hierarchy among incarcerated men by constructing violent masculinity as a subcultural norm. The results suggest that the gender code in prison represents a set of rules that create opportunities for men to police each other’s gender performance and make claims to masculine statuses. Because status is inextricably tied to survival in this context, many men feel pressured to perform violent masculinities in prison despite privately subscribing to a non-violent sense of self-concept. The results suggest that violence is an expressive and instrumental resource for men in prison. A gender theory of prison violence, methodological findings, theoretical implications, ethical considerations and the short and long term aftermath of violent prison conflict are discussed.

Comparisons of an aerosol transport model with a 4-year analysis of summer aerosol optical depth retrievals over the Canadian Arctic

Abstract : This is a study concerning comparisons between the Dubovik Aerosol optical depth (AOD) retrievals from AEROCAN (ARONET) stations and AOD estimates from simulations provided by a chemical transport model (GEOS-Chem : Goddard Earth Observing System Chemistry). The AOD products associated with the Dubovik product are divided into total, fine and coarse mode components. The retrieval period is from January 2009 to January 2013 for 5 Arctic stations (Barrow, Alaska; Resolute Bay, Nunavut; 0PAL and PEARL (Eureka), Nunavut; and Thule, Greenland). We also employed AOD retrievals from 10 other mid-latitude Canadian stations for comparisons with the Arctic stations. The results of our investigation were submitted to Atmosphere-Ocean. To briefly summarize those results, the model generally but not always tended to underestimate the (monthly) averaged AOD and its components. We found that the subdivision into fine and coarse mode components could provide unique signatures of particular events (Asian dust) and that the means of characterizing the statistics (log-normal frequency distributions versus normal distributions) was an attribute that was common to both the retrievals and the model.

How are Canadian universities training and supporting undergraduate medical, physiotherapy and occupational students for global health experiences in international low-resource settings?

Abstract : OBJECTIVES : Canadian medical (MD), physiotherapy (PT) and occupational therapy (OT) students increasingly show an interest in global health experiences (GHEs). As certain moral hazards can occur as a result of student GHEs, a growing consensus exists that universities must have an established selection process, in-depth pre-departure training (PDT), adequate onsite supervision and formal debriefing for their students. This study aimed at identifying current practices in Canadian MD, PT and OT programs and discussing areas for improvement by comparing them with recommendations found in the literature. METHODS : Canadian MD, PT and OT programs (n = 45) were invited to answer an online survey about their current practices for GHE support and training. The survey included 24 close-ended questions and 18 open-ended questions. Descriptive statistics and a thematic analysis were performed on the data and results were discussed with recommendations found in the literature. RESULTS : Twenty-three programs responded to the survey. Student selection processes varied across universities; examples included using academic performance, interviews and motivation letters. All but 1 MD program had mandatory PDT; content and teaching formats varied, as did training duration (2-38 hours). All but 1 MD program had onsite supervision; local clinicians were frequently involved. Debriefing, although not systematic, covered similar content; debriefing was variable in duration (1-8 hours). CONCLUSIONS : Many current practices are encouraging but areas for improvement exist. Integrating global health content into the regular curriculum with advanced study option in global health for students participating in GHEs could help universities standardize support and training.