Michael Sawada

Millennial-scale temperature variations in North America during the Holocene

[1] A mean continental July temperature reconstruction based on pollen records from across North America quantifies temperature variations of several timescales for the past 14,000 cal yr BP. In North America, temperatures increased nearly 4� C during the late glacial, reaching maximum values between 6000 and 3000 cal yr BP, after which mean July temperatures decreased. Superimposed on this orbital-scale trend are millennial-scale temperature variations that appear coherent in structure and frequency with highresolution ice, marine and other terrestrial paleoclimate records of the Holocene. During the Holocene, climate in North America appears to have varied periodically every � 1100 years rather than the � 1500 year cycle found during the last glacial period. Coherence at frequencies between 900 and 1100 years between land, ice, and ocean records suggests a common forcing associated with widespread surface impacts during the Holocene. These results provide important insight to the global warming debate, as the observed twentieth century temperature increase appears unprecedented compared to our mean North American temperature reconstruction of the past 14,000 years.

Sphagnum peatland distribution in North America and Eurasia during the past 21,000 years

The distribution and abundance of Sphagnum spores in North America and Eurasia are mapped for the past 21 ka. The present-day distribution of abundant Sphagnum spores corresponds closely to areas with peatland development, with maximum Sphagnum abundance between 630 and 1300 mm annual precipitation and between −2° and 6°C mean annual air temperature. During the Wisconsin glaciation, there were apparently not large areas of peatland in North America, except in Alaska. High Sphagnum spore percentages were found in eastern North America during deglaciation. Major peatland development occurred in boreal North America after 9 ka and there was a southward movement of high Sphagnum spore abundance after 5 ka in the western Great Lakes region. Major peatland development began after 9 ka in Europe and Asia. On the basis of maps of the area supporting peatlands, carbon accumulation in peatlands is estimated to be low prior to 11 ka, increased slightly between 11 and 5 ka, and greatly increased during the past 5 ka.

A multilevel analysis of neighbourhood built and social environments and adult self-reported physical activity and body mass index in Ottawa, Canada

Canadian research examining the combined effects of social and built environments on physical activity (PA) and obesity is limited. The purpose of this study was to determine the relationships among built and social environments and PA and overweight/obesity in 85 Ottawa neighbourhoods. Self-reported PA, height and weight were collected from 3,883 adults using the International PA Questionnaire from the 2003–2007 samples of the Rapid Risk Factor Surveillance System. Data on neighbourhood characteristics were obtained from the Ottawa Neighbourhood Study; a large study of neighbourhoods and health in Ottawa. Two-level binomial logistic regression models stratified by sex were used to examine the relationships of environmental and individual variables with PA and overweight/obesity while using survey weights. Results identified that approximately half of the adults were insufficiently active or overweight/obese. Multilevel models identified that for every additional convenience store, men were two times more likely to be physically active (OR = 2.08, 95% CI: 1.72, 2.43) and with every additional specialty food store women were almost two times more likely to be overweight or obese (OR = 1.77, 95% CI: 1.33, 2.20). Higher green space was associated with a reduced likelihood of PA (OR = 0.93, 95% CI: 0.86, 0.99) and increased odds of overweight and obesity in men (OR = 1.10, 95% CI: 1.01, 1.19), and decreased odds of overweight/obesity in women (OR = 0.66, 95% CI: 0.44, 0.89). In men, neighbourhood socioeconomic scores, voting rates and sense of community belonging were all significantly associated with overweight/obesity. Intraclass coefficients were low, but identified that the majority of neighbourhood variation in outcomes was explained by the models. Findings identified that green space, food landscapes and social cohesiveness may play different roles on PA and overweight/obesity in men and women and future prospective studies are needed.

Relationships Between Neighborhoods, Physical Activity, and Obesity: A Multilevel Analysis of a Large Canadian City

In Canada, there is limited research examining the associations between objectively measured neighborhood environments and physical activity (PA) and obesity. The purpose of this study was to determine the relationships between variables from built and social environments and PA and overweight/obesity across 86 Ottawa, Canada neighborhoods. Individual‐level data including self‐reported leisure‐time PA (LTPA), height, and weight were examined in a sample of 4,727 adults from four combined cycles (years 2001/03/05/07) of the Canadian Community Health Survey (CCHS). Data on neighborhood characteristics were obtained from the Ottawa Neighbourhood Study (ONS); a large study of neighborhoods and health in Ottawa, Canada. Binomial multivariate multilevel models were used to examine the relationships between environmental and individual variables with LTPA and overweight/obesity using survey weights in men and women separately. Within the sample, ∼75% of the adults were inactive (<3.0 kcal/kg/day) while half were overweight/obese. Results of the multilevel models suggested that for females greater park area was associated with increased odds of LTPA and overweight/obesity. Greater neighborhood density of convenience stores and fast food outlets were associated with increased odds of females being overweight/obese. Higher crime rates were associated with greater odds of LTPA in males, and lower odds of male and female overweight/obesity. Season was significantly associated with PA in men and women; the odds of LTPA in winter months were half that of summer months. Findings revealed that park area, crime rates, and neighborhood food outlets may have different roles with LTPA and overweight/obesity in men and women and future prospective studies are needed.

The Modifiable Areal Unit Problem (MAUP) in the Relationship between Exposure to NO2 and Respiratory Health

BackgroundMany Canadian population health studies, including those focusing on the relationship between exposure to air pollution and health, have operationalized neighbourhoods at the census tract scale. At the same time, the conceptualization of place at the local scale is one of the weakest theoretical aspects in health geography. The modifiable areal unit problem (MAUP) raises issues when census tracts are used as neighbourhood proxies, and no other alternate spatial structure is used for sensitivity analysis. In the literature, conclusions on the relationship between NO2 and health outcomes are divided, and this situation may in part be due to the selection of an inappropriate spatial structure for analysis. Here, we undertake an analysis of NO2 and respiratory health in Ottawa, Canada using three different spatial structures in order to elucidate the effects that the spatial unit of analysis can have on analytical results.ResultsUsing three different spatial structures to examine and quantify the relationship between NO2 and respiratory morbidity, we offer three main conclusions: 1) exploratory spatial analytical methods can serve as an indication of the potential effect of the MAUP; 2) OLS regression results differ significantly using different spatial representations, and this could be a contributing factor to the lack of consensus in studies that focus on the relation between NO2 and respiratory health at the area-level; and 3) the use of three spatial representations confirms no measured effect of NO2 exposure on respiratory health in Ottawa.ConclusionsArea units used in population health studies should be delineated so as to represent the a priori scale of the expected scale interaction between neighbourhood processes and health. A thorough understanding of the role of the MAUP in the study of the relationship between NO2 and respiratory health is necessary for research into disease pathways based on statistical models, and for decision-makers to assess the scale at which interventions will have maximum benefit. In general, more research on the role of spatial representation in health studies is needed.

Analysis of the urban/rural broadband divide in Canada: Using GIS in planning terrestrial wireless deployment

Abstract Millions of Canadians residing in Canadas northern, isolated, rural, and remote communities do not have broadband Internet access. This situation has led to a national “broadband divide.” That is, the deployment of wireline broadband is very limited in Canadas northern, isolated, rural, and remote areas because of the significant expense of installation and maintenance of the wired infrastructure needed to reach dwellings in these locations. Terrestrial broadband wireless technology, on the other hand, does not entail the same kind of physical infrastructure. As a result, there are dramatic changes in how spatial considerations affect the provision of broadband Internet services (BIS) to areas beyond the urban zone. In particular, the spatial question is now focused on assessing the capacity for different technological solutions to reach profitable population bases, and brings to the forefront organizations that are developing non-line-of-sight (NLOS) technologies that would permit wireless Internet access over much greater distances than current solutions. We begin this paper by establishing the importance of broadband connectivity to Canadas northern, isolated, rural, and remote communities. This discussion comments on the role of the Government of Canada in the provision of broadband connectivity to residents of these communities, and outlines the current regulatory issues that govern wireless services and policy formulation. The second part of the paper illustrates the use of geographic information system (GIS) approaches in the study of wireless broadband planning and deployment. Case study findings suggest that GIS applications can make a significant contribution to the analysis of wireless deployment planning, to the understanding of the relationships between wireless signal sources and consumers, and to the spatial configuration of terrestrial wireless broadband networks. We conclude the paper by discussing how the GIS approach employed could be used to inform the public policy process with regard to increasing access to broadband Internet services in all regions of the country, and thereby providing the opportunity for all Canadians, regardless of location, to fully participate in the Information Society.

An open source implementation of the Modern Analog Technique (MAT) within the R computing environment

The purpose of this paper is to introduce an analytical solution for Quaternary geoscientists applying the modern analog technique (MAT) to fossil biological assemblages. We present a package called MATTOOLS that implements the MAT and offers new calibration techniques related to Monte Carlo simulation and response operating curves (ROC) that are used in assessing the critical thresholds of biological assemblage dissimilarity. The MATTOOLS solution to the MAT has the advantage of operating in the R language environment, a free open-source high-level language with hundreds of functions for statistical analysis and visualization. MATTOOLS therefore offers an easily extensible solution for individual research endeavors. We review current solutions for MAT calculations and provide an example of modern calibration using MATTOOLS.

A comparison of classification algorithms using Landsat-7 and Landsat-8 data for mapping lithology in Canada’s Arctic

To map Arctic lithology in central Victoria Island, Canada, the relative performance of advanced classifiers (Neural Network (NN), Support Vector Machine (SVM), and Random Forest (RF)) were compared to Maximum Likelihood Classifier (MLC) results using Landsat-7 and Landsat-8 imagery. A ten-repetition cross-validation classification approach was applied. Classification performance was evaluated visually and statistically using the global classification accuracy, producer’s and user’s accuracies for each individual lithological/spectral class, and cross-comparison agreement. The advanced classifiers outperformed MLC, especially when training data were not normally distributed. The Landsat-8 classification results were comparable to Landsat-7 using the advanced classifiers but differences were more pronounced when using MLC. Rescaling the Landsat-8 data from 16 bit to 8 bit substantially increased classification accuracy when MLC was applied but had little impact on results from the advanced classifiers.

Mapping as a knowledge translation tool for Ontario Early Years Centres: views from data analysts and managers

BackgroundLocal Ontario Early Years Centres (OEYCs) collect timely and relevant local data, but knowledge translation is needed for the data to be useful. Maps represent an ideal tool to interpret local data. While geographic information system (GIS) technology is available, it is less clear what users require from this technology for evidence-informed program planning. We highlight initial challenges and opportunities encountered in implementing a mapping innovation (software and managerial decision-support) as a knowledge translation strategy.MethodsUsing focus groups, individual interviews and interactive software development events, we taped and transcribed verbatim our interactions with nine OEYCs in Ontario, Canada. Research participants were composed of data analysts and their managers. Deductive analysis of the data was based on the Ottawa Model of Research Use, focusing on the innovation (the mapping tool and maps), the potential adopters, and the environment.ResultsChallenges associated with the innovation included preconceived perceptions of a steep learning curve with GIS software. Challenges related to the potential adopters included conflicting ideas about tool integration into the organization and difficulty with map interpretation. Lack of funds, lack of availability of accurate data, and unrealistic reporting requirements represent environmental challenges.ConclusionDespite the clear need for mapping software and maps, there remain several challenges to their effective implementation. Some can be modified, while other challenges might require attention at the systemic level. Future research is needed to identify barriers and facilitators related to using mapping software and maps for decision-making by other users, and to subsequently develop mapping best practices guidelines to assist community-based agencies in circumventing some challenges, and support information equity across a region.

If you build it, they still may not come: outcomes and process of implementing a community-based integrated knowledge translation mapping innovation

BackgroundMaps and mapping tools through geographic information systems (GIS) are highly valuable for turning data into useful information that can help inform decision-making and knowledge translation (KT) activities. However, there are several challenges involved in incorporating GIS applications into the decision-making process. We highlight the challenges and opportunities encountered in implementing a mapping innovation as a KT strategy within the non-profit (public) health sector, reflecting on the processes and outcomes related to our KT innovations.MethodsA case study design, whereby the case is defined as the data analyst and manager dyad (a two-person team) in selected Ontario Early Year Centres (OEYCs), was used. Working with these paired individuals, we provided a series of interventions followed by one-on-one visits to ensure that our interventions were individually tailored to personal and local decision-making needs. Data analysis was conducted through a variety of qualitative assessments, including field notes, interview data, and maps created by participants. Data collection and data analysis have been guided by the Ottawa Model of Research Use (OMRU) conceptual framework.ResultsDespite our efforts to remove all barriers associated with our KT innovation (maps), our results demonstrate that both individual level and systemic barriers pose significant challenges for participants. While we cannot claim a causal association between our project and increased mapping by participants, participants did report a moderate increase in the use of maps in their organization. Specifically, maps were being used in decision-making forums as a way to allocate resources, confirm tacit knowledge about community needs, make financially-sensitive decisions more transparent, evaluate programs, and work with community partners.ConclusionsThis project highlights the role that maps can play and the importance of communicating the importance of maps as a decision support tool. Further, it represents an integrated knowledge project in the community setting, calling to question the applicability of traditional KT approaches when community values, minimal resources, and partners play a large role in decision making. The study also takes a unique perspective--where research producers and users work as dyad-pairs in the same organization--that has been under-explored to date in KT studies.