A Spatial Analysis of Individual- and Neighborhood-Level Determinants of Malaria Incidence in Adults, Ontario, Canada

Emerging Infectious Diseases Journal, Volume 18, Number 5—May 2012

Rose Eckhardt, Lea Berrang-Ford, Nancy A. Ross, Dylan R. Pillai, and David L. Buckeridge

“Malaria, once endemic in Canada, is now restricted to imported cases. Imported malaria in Canada has not been examined recently in the context of increased international mobility, which may influence incidence of imported and autochthonous cases. Surveillance of imported cases can highlight high-risk populations and help target prevention and control measures. To identify geographic and individual determinants of malaria incidence in Ontario, Canada, we conducted a descriptive spatial analysis. We then compared characteristics of case-patients and controls.

Percentage of residents in a neighborhood reporting immigration from malaria-endemic areas, greater Toronto area, Ontario, Canada, 2008–2009.

Percentage of residents in a neighborhood reporting immigration from malaria-endemic areas, greater Toronto area, Ontario, Canada, 2008–2009. Red dots, malaria case-patients (positive test results); blue circles, controls (negative test results).

“Case-patients were significantly more likely to be male and live in low-income neighborhoods that had a higher proportion of residents who had emigrated from malaria-endemic regions. This method’s usefulness in clarifying the local patterns of imported malaria in Ontario shows its potential to help identify areas and populations at highest risk for imported and emerging infectious disease.”

Producing an Indigenous Knowledge Web GIS for Arctic Alaska Communities: Challenges, Successes, and Lessons Learned

Transactions in GISTransactions in GIS, Volume 16, Issue 1, February 2012

Wendy R. Eisner, Jessica Jelacic, Chris J. Cuomo, Changjoo Kim, Kenneth M. Hinkel and Dorin Del Alba

“A traditional knowledge “Iñupiaq Web GIS”, based on a five-year study and containing observations and environmental knowledge of Iñupiat communities indigenous to Arctic Alaska, was incorporated into a Web-based platform. The website, “Arctic Cultural Cartography,” was created to be an open portal through which the password-protected “Iñupiaq Web GIS” could be accessed. We discuss the process of developing the web GIS including the incorporation of user-friendly features such as links to interactive maps, video clips of interviews, discussion boards, and the integration of popular web interfaces such as Facebook.

Layout of Iñupiaq Web GIS

Layout of “Iñupiaq Web GIS”

“We also discuss short- and long-term goals for the further development of the GIS, its potential as a sustainable, participatory online database for sharing pertinent ecological knowledge, and challenges in achieving optimal community involvement given constraints imposed by remote locations with limited bandwidth.”

Computer-Based Synthetic Data to Assess the Tree Delineation Algorithm from Airborne LiDAR Survey

GeoInformaticaGeoInformatica, Published Online 28 November 2011

Lei Wang, Andrew G. Birt, Charles W. Lafon, David M. Cairns, Robert N. Coulson, Maria D. Tchakerian, Weimin Xi, Sorin C. Popescu and James M. Guldin

“Small Footprint LiDAR (Light Detection And Ranging) has been proposed as an effective tool for measuring detailed biophysical characteristics of forests over broad spatial scales. However, by itself LiDAR yields only a sample of the true 3D structure of a forest. In order to extract useful forestry relevant information, this data must be interpreted using mathematical models and computer algorithms that infer or estimate specific forest metrics. For these outputs to be useful, algorithms must be validated and/or calibrated using a sub-sample of ‘known’ metrics measured using more detailed, reliable methods such as field sampling. In this paper we describe a novel method for delineating and deriving metrics of individual trees from LiDAR data based on watershed segmentation. Because of the costs involved with collecting both LiDAR data and field samples for validation, we use synthetic LiDAR data to validate and assess the accuracy of our algorithm. This synthetic LiDAR data is generated using a simple geometric model of Loblolly pine (Pinus taeda) trees and a simulation of LiDAR sampling. Our results suggest that point densities greater than 2 and preferably greater than 4 points per m2 are necessary to obtain accurate forest inventory data from Loblolly pine stands. However the results also demonstrate that the detection errors (i.e. the accuracy and biases of the algorithm) are intrinsically related to the structural characteristics of the forest being measured. We argue that experiments with synthetic data are directly useful to forest managers to guide the design of operational forest inventory studies. In addition, we argue that the development of LiDAR simulation models and experiments with the data they generate represents a fundamental and useful approach to designing, improving and exploring the accuracy and efficiency of LiDAR algorithms.”

Geo-Environmental Effect of Landfill Site, Southeast of Riyadh, Saudi Arabia

Arabian Journal of GeosciencesArabian Journal of Geosciences, Published Online 01 February 2012

Oumar Allafouza Loni, M. Tahir Hussein and Ayman M. Alrehaili

“Landfilled wastes manifest slow decomposition, producing emanation of gases, and outflow of leachate. Waste mass shows various chemical reactions and complex evolutions that occur under the influence of natural agents, as rain and microorganisms. These reactions lead to biological, physical, and chemical transformations of wastes. The intensity of the phenomenon is related to the air and the humidity. These factors originate from the initial composition of the solid waste, the operating mode of the landfill, and the geological and hydrogeological conditions. Leachate is considered a major source of groundwater pollution. It has a complex nature; it typically contains high concentrations of chemical hazardous including heavy metals, chemical compounds that may severely pollute the environment. These challenges are faced all over the world by environment protection agencies and waste management bodies. The challenge differs according to the specific situation of the site, the climatic, environmental, and geological factors. The international literature is rich with studies in this concern. Each country or region of the world has its own legislation and laws governing waste management, e.g., the European Commission Legislation, the US Environmental Agency, and so forth. The main objective of this study is to shed light on the environmental consequences of a landfill site located in the southeast of Riyadh City, Saudi Arabia. It constitutes a peculiar case because of its situation, its exploitation mode, and nature of buried wastes. The study made use of satellite MSS, TM, ETM and SPOT image 2007, and Digital Elevation Model (DEM), respectively. Geological, morphological, hydrological, hydrochemical, and detailed drainage analyses were performed. Records of meteorological stations were also used in this study. The satellite images illustrate the evolution of the site through time since its start in the 1990s of the twentieth century. The main geological units outcropping in the area are the Sulaiy Formation, the Yamama Formation, Khabra deposits, floodplain deposits, alluvium, and sheet gravel. Drainage analyses shows a dendritic nature for the network, a total area of 2,113 km2, basin slope of 0.016, perimeter of 430 × 103, and a mean elevation of 635 m. Annual rainfall is around 100 mm, evapotranspiration is about 2,900 mm, wind speed averages at 5.1 km/h, and runoff peak is within 2.7–4.7 m3/s. A plume of total dissolved solids and nitrates was observed to initiate from the landfill site. Heavy metal concentration confirms the same result. Planners, environmentalists, decision makers, and other interest groups can use the findings of this study for environmental management of the landfill and protection of the downstream part of the Sulaiy tributary from leachate contamination. The results indicate the importance of monitoring landfills through the combined use of ground and satellite monitoring.”

A Simplified GIS Approach to Modeling Global Leaf Water Isoscapes

PLoS ONE, published 18 Jun 2008

Jason B. West, Adam Sobek, and James R. Ehleringer

“The stable hydrogen (δ2H) and oxygen (δ18O) isotope ratios of organic and inorganic materials record biological and physical processes through the effects of substrate isotopic composition and fractionations that occur as reactions proceed. At large scales, these processes can exhibit spatial predictability because of the effects of coherent climatic patterns over the Earth’s surface. Attempts to model spatial variation in the stable isotope ratios of water have been made for decades. Leaf water has a particular importance for some applications, including plant organic materials that record spatial and temporal climate variability and that may be a source of food for migrating animals. It is also an important source of the variability in the isotopic composition of atmospheric gases. Although efforts to model global-scale leaf water isotope ratio spatial variation have been made (especially of δ18O), significant uncertainty remains in models and their execution across spatial domains.

Global mean annual average leaf water

Global mean annual average leaf water δ18O and δ2H isoscapes for the sites of evaporation within leaves (Flat Polar Quartic projection; Two-pool and Péclet models gave similar, less enriched results).

“We introduce here a Geographic Information System (GIS) approach to the generation of global, spatially-explicit isotope landscapes ( = isoscapes) of “climate normal” leaf water isotope ratios. We evaluate the approach and the resulting products by comparison with simulation model outputs and point measurements, where obtainable, over the Earth’s surface. The isoscapes were generated using biophysical models of isotope fractionation and spatially continuous precipitation isotope and climate layers as input model drivers. Leaf water δ18O isoscapes produced here generally agreed with latitudinal averages from GCM/biophysical model products, as well as mean values from point measurements. These results show global-scale spatial coherence in leaf water isotope ratios, similar to that observed for precipitation and validate the GIS approach to modeling leaf water isotopes. These results demonstrate that relatively simple models of leaf water enrichment combined with spatially continuous precipitation isotope ratio and climate data layers yield accurate global leaf water estimates applicable to important questions in ecology and atmospheric science.”