5 resultados para Uncertainty and disturbance

em QSpace: Queen's University - Canada


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This paper explores the ways in which the construction of militarized masculinities in Cold War Canadian media reflected the hegemonic masculinities and broader social trends of the period. This paper focuses specifically on the recruiting materials produced for and by the Canadian Army between 1956 and 1959, the time of the Suez Canal Crisis and the beginnings of “Canadian peacekeeping.” Through the mobilization of modern and anti-modern masculine identities attached to hegemonic and idealized Cold War Canadian masculinities, the Army created the image of the “Modern Warrior” to portray itself as an occupation and culture for “real Canadian men.” This identity simultaneously corresponded with Canada’s new “peacekeeping” identity. By presenting certain images of Canadian manhood as the “ideal” Canadian identity and by associating this “ideal” masculinity with military service, the Army’s recruitment advertisements conflated Cold War rhetoric of service, defence, national citizenship, cultural belonging, and “ideal” ethnicity with a Canadian identity available only to a specific (and often exclusive) segment of society. Because military service has long been considered the crux of citizenship, these advertisements (re)entrenched patterns of middle-class, heterosexual, Anglo- Saxon masculine power and dominance in a time of social uncertainty and cultural anxiety through the reaffirmation of this group’s “privilege” to serve the nation.

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Climate change is expected to have marked impacts on forest ecosystems. In Ontario forests, this includes changes in tree growth, stand composition and disturbance regimes, with expected impacts on many forest-dependent communities, the bioeconomy, and other environmental considerations. In response to climate change, renewable energy systems, such as forest bioenergy, are emerging as critical tools for carbon emissions reductions and climate change mitigation. However, these systems may also need to adapt to changing forest conditions. Therefore, the aim of this research was to estimate changes in forest growth and forest cover in response to anticipated climatic changes in the year 2100 in Ontario forests, to ultimately explore the sustainability of bioenergy in the future. Using the Haliburton Forest and Wildlife Reserve in Ontario as a case study, this research used a spatial climate analog approach to match modeled Haliburton temperature and precipitation (via Fourth Canadian Regional Climate Model) to regions currently exhibiting similar climate (climate analogs). From there, current forest cover and growth rates of core species in Haliburton were compared to forests plots in analog regions from the US Forest Service Forest Inventory and Analysis (FIA). This comparison used two different emission scenarios, corresponding to a high and a mid-range emission future. This research then explored how these changes in forests may influence bioenergy feasibility in the future. It examined possible volume availability and composition of bioenergy feedstock under future conditions. This research points to a potential decline of softwoods in the Haliburton region with a simultaneous expansion of pre-established hardwoods such as northern red oak and red maple, as well as a potential loss in sugar maple cover. From a bioenergy perspective, hardwood residues may be the most feasible feedstock in the future with minimal change in biomass availability for energy production; under these possible conditions, small scale combined heat and power (CHP) and residential pellet use may be the most viable and ecologically sustainable options. Ultimately, understanding the way in which forests may change is important in informing meaningful policy and management, allowing for improved forest bioenergy systems, now and in the future.

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To effectively assess and mitigate risk of permafrost disturbance, disturbance-p rone areas can be predicted through the application of susceptibility models. In this study we developed regional susceptibility models for permafrost disturbances using a field disturbance inventory to test the transferability of the model to a broader region in the Canadian High Arctic. Resulting maps of susceptibility were then used to explore the effect of terrain variables on the occurrence of disturbances within this region. To account for a large range of landscape charac- teristics, the model was calibrated using two locations: Sabine Peninsula, Melville Island, NU, and Fosheim Pen- insula, Ellesmere Island, NU. Spatial patterns of disturbance were predicted with a generalized linear model (GLM) and generalized additive model (GAM), each calibrated using disturbed and randomized undisturbed lo- cations from both locations and GIS-derived terrain predictor variables including slope, potential incoming solar radiation, wetness index, topographic position index, elevation, and distance to water. Each model was validated for the Sabine and Fosheim Peninsulas using independent data sets while the transferability of the model to an independent site was assessed at Cape Bounty, Melville Island, NU. The regional GLM and GAM validated well for both calibration sites (Sabine and Fosheim) with the area under the receiver operating curves (AUROC) N 0.79. Both models were applied directly to Cape Bounty without calibration and validated equally with AUROC's of 0.76; however, each model predicted disturbed and undisturbed samples differently. Addition- ally, the sensitivity of the transferred model was assessed using data sets with different sample sizes. Results in- dicated that models based on larger sample sizes transferred more consistently and captured the variability within the terrain attributes in the respective study areas. Terrain attributes associated with the initiation of dis- turbances were similar regardless of the location. Disturbances commonly occurred on slopes between 4 and 15°, below Holocene marine limit, and in areas with low potential incoming solar radiation

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This paper is concerned with strategic optimization of a typical industrial chemical supply chain, which involves a material purchase and transportation network, several manufacturing plants with on-site material and product inventories, a product transportation network and several regional markets. In order to address large uncertainties in customer demands at the different regional markets, a novel robust scenario formulation, which has been developed by the authors recently, is tailored and applied for the strategic optimization. Case study results show that the robust scenario formulation works well for this real industrial supply chain system, and it outperforms the deterministic formulation and the classical scenario-based stochastic programming formulation by generating better expected economic performance and solutions that are guaranteed to be feasible for all uncertainty realizations. The robust scenario problem exhibits a decomposable structure that can be taken advantage of by Benders decomposition for efficient solution, so the application of Benders decomposition to the solution of the strategic optimization is also discussed. The case study results show that Benders decomposition can reduce the solution time by almost an order of magnitude when the number of scenarios in the problem is large.

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Background: Shiftwork is associated with increased sleep disturbance and cardiovascular and metabolic disease risk. This thesis will focus on shiftwork-related sleep disturbance and the potential mediating role of reduced sleep duration in the relationship between a current rotational shiftwork schedule and the metabolic syndrome among female hospital employees. Objectives: 1) To describe sleep patterns in relation to different shiftwork exposure metrics (current status, cumulative exposure, number of consecutive night shifts); 2) To assess the association between shiftwork metrics and sleep duration; 3) To determine whether sleep duration on work shifts mediates the relationship between a current rotational shiftwork pattern and the metabolic syndrome; and 4) To assess whether cumulative shiftwork exposure and the number of consecutive night shifts are associated with the metabolic syndrome. Methods: 294 female hospital employees (142 rotating shiftworkers, 152 dayworkers) participated in a cross-sectional study. Shiftwork parameters were determined through self-report. Sleep was measured for one week with the ActiGraph GT3X+, a tri-axial accelerometer. The metabolic syndrome was defined according to the Joint Interim Studies Consensus Statement. Sleep was described by shiftwork exposure parameters, and multivariable linear regression was used to determine associations between shiftwork variables and sleep duration. Regression path analysis was used to assess whether sleep duration was a mediator between a current shiftwork schedule and the metabolic syndrome, and the significance of the indirect (mediating) effect was tested with bootstrap confidence intervals. Logistic regression was used to determine associations between cumulative shiftwork exposure, number of consecutive night shifts, and the metabolic syndrome. Results: Current shiftworkers slept less on work shifts, more on free days, and were more likely to nap compared to dayworkers. Sleep duration on work shifts was a strong intermediate in the relationship between a current shiftwork pattern and the metabolic syndrome. Cumulative shiftwork exposure and the number of consecutive night shifts did not affect sleep or the metabolic syndrome. Conclusions: A current shiftwork pattern disrupts sleep, and reduced sleep duration is an important intermediate between shiftwork and the metabolic syndrome among female hospital employees.