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Search Results: 1 - 10 of 220172 matches for " Edmund C; "
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A Parallel Processing Algorithm for Computing Short-Range Particle Forces with Inhomogeneous Particle Distributions
Robert C. Ferrell,Edmund Bertschinger
Physics , 1995,
Abstract: We present a computational algorithm for computing short range forces between particles. The algorithm has two distinguishing features. First, it is optimized for multi-processor computers, and will use as many processors as are available. Second, it is optimized for inhomogeneous, dynamic particle distributions; for any distribution the computational load is distributed evenly to all processors, and the communication time is less than 15\% of the total run time. In this talk we present our new algorithm. We developed the program for a grand-challenge problem in cosmology, simulation of the formation of large-scale structure in the universe. This simulation, run on the Thinking Machines Corporation CM-5, uses the particle-particle/particle-mesh (PPPM) \cite{hock_east} algorithm. The particle-particle phase is computed using the algorithm we describe in this paper. We discuss this and other applications.
GIS and Remote Sensing Applications in the Assessment of Change within a Coastal Environment in the Niger Delta Region of Nigeria
Yaw A. Twumasi,Edmund C. Merem
International Journal of Environmental Research and Public Health , 2006, DOI: 10.3390/ijerph2006030011
Abstract: In the last decades, the Niger Delta region has experienced rapid growth in population and economicv activity with enormous benefits to the adjacent states and the entire Nigerian society. As the region embarks upon an unprecedented phase of economic expansion in the 21st century, it faces several environmental challenges fuelled partly by the pressures caused by human activities such as oil and gas exploration, housing development, and road construction for transportation, economic development and demographic changes. This continued growth has resulted in environmental problems such as coastal wetland loss, habitat degradation, and water pollution, gas flaring, destruction of forest vegetation as well as a host of other issues. This underscores the urgent need to design new approaches for managing remote costal resources in sensitive tropical environments effectively in order to maintain a balance between coastal resource conservation and rapid economic development in developing countries for sustainability. Notwithstanding previous initiatives, there have not been any major efforts in the literature to undertake a remote sensing and GIS based assessment of the growing incidence of environmental change within coastal zone environments of the study area. This project is an attempt to fill that void in the literature by exploring the applications of GIS and remote sensing in a tropical coastal zone environment with emphasis on the environmental impacts of development in the Niger Delta region of Southern Nigeria. To deal with some of the aforementioned issues, several research questions that are of great relevance to the paper have been posed. The questions include, Have there been any changes in the coastal environment of the study area? What are the impacts of the changes? What forces are responsible for the changes? Has there been any major framework in place to deal with the changes? The prime objective of the paper is to provide a novel approach for assessing the state of coastal environments while the second objective seeks a contribution to the literature. The third objective is to provide a decision support tool for coastal resource managers in the assessment of environmental impacts of development in tropical areas. The fourth objective is to assess the extent of change in a tropical ecosystem with the latest advances in geo-spatial information technologies and methods. In terms of methodology, the paper draws from primary and census data sources analyzed with descriptive statistics, GIS techniques and remote sensing. The sections in the paper consist of a review of the major environmental effects and factors associated with the problem: initiatives and mitigation measures. The project offers some recommendations as part of the conservation strategies. In spite of concerted efforts by managers to address the problems, results revel that the study area experienced some significant changes in its coastal environments. These changes are attributed to socio-economic and environmental variables.
GIS Applications in Land Management: The Loss of High Quality Land to Development in Central Mississippi from 1987-2002
Yaw A. Twumasi,Edmund C. Merem
International Journal of Environmental Research and Public Health , 2005, DOI: 10.3390/ijerph2005020006
Abstract: The socio-economic trends and history of Central Mississippi reveal a major rural influence based upon a dependence on agricultural activities as part of the economic engine driving the state’s economy. Yet, in the last several years, the amount of agricultural land in the counties continues to decline. Similar changes in other variables associated with agricultural land use and the continuity of farming in the state have also been changing. Indeed, under the pressure of urban growth, some farmers are forced to use less productive soils or have abandoned the agricultural business. Considering the gravity of the problem and the implications for sustainable development, public concern has increased in the state of Mississippi that urbanization and other factors may be eroding potential farmland. Given the effects of the current trends on the future capacity to produce food items, there are concerns that the growing incidence of farmland loss may also erode the basis for sustainable use of agricultural land, biodiversity and protection of the state’s ecological treasures. Notwithstanding the gravity of these trends, no major effort in the literature has aimed at documenting the incidence of agricultural land loss and the linkages to urbanization in the region of Central Mississippi. What changes have taken place in the size of agricultural land within the counties and what factors are responsible for it? This paper examines the issue of farmland loss in Central Mississippi with a focus at the county level between 1987 and 2002 from a temporal-spatial perspective. In terms of methodology, the paper uses a mixed scale approach based upon the existing literature. Data were drawn from the United States Census databases of Population and Agriculture. This information is analyzed with basic descriptive statistics and GIS with particular attention to the spatial trends at the county level. Results indicate that the counties under consideration have experienced considerable change in the amount of agricultural land and other variables associated with the use of farmland, due to urbanization. With the types of changes occurring, instituting effective policies anchored in sustainability, community participation, and growth management will go a long way in addressing the situation. Other strategies for farmland protection based upon land information inventory and mapping in the region, are also recommended. The paper stands as an update of the existing literature and offers a valuable tool for decision makers within the domain of natural resources management.
Using Remote Sensing and GIS in the Analysis of Ecosystem Decline along the River Niger Basin: The Case of Mali and Niger
Yaw A. Twumasi,Edmund C. Merem
International Journal of Environmental Research and Public Health , 2007, DOI: 10.3390/ijerph2007040013
Abstract: In the Sub-Saharan African region of the River Niger Basin, where none of the major rivers is fully contained within the borders of a single nation, riverine ecosystem health monitoring is essential for survival. Even the globally proclaimed goals of sustainability and environmental security in the region are unattainable without using geospatial technologies of remote sensing and Geographic Information Systems (GIS) as conduits for environmental health within shared waters. Yet the systematic study of the nature of cooperation between states over shared water resources in troubled areas of the Middle East continues to dominate the literature with minimal coverage of the Sub-Saharan Africa experience and the role of GIS and remote sensing in monitoring the problem. Considering the intense ecosystem stress inflicted on River Niger by human activities and natural forces emanating from upstream and downstream nations. Researching the growing potential for acute riverine ecosystem decline among the nations of Niger and Mali along the River Niger Basin with the latest advances in spatial information technology as a decision support tool not only helps in ecosystem recovery and the avoidance of conflicts, but it has the potentials to bring countries much closer through information exchange. While the nature of the problem remains compounded due to the depletion of available water resources and environmental resources within shared waters, the lack of information exchange extracts ecological costs from all players. This is essential as the Niger Basin nations move towards a multinational watershed management as a conduit for sustainability. To confront these problems, some research questions with relevance to the paper have been posed. The questions include, Have there been any declines in the riverine ecosystem of the study area? What are the effects and what factors trigger the changes? What mitigation measures are in place for dealing with the problems? The first objective of the paper is to develop a new framework for analyzing the health of riverine ecosystems while the second objective seeks a contribution to the literature. The third objective is to design a geo-spatial tool for riverine ecosystem management and impact analysis. The fourth objective is to measure the nature of change in riverine environments with the latest advances in geo-spatial information technologies and methods. In terms of methodology, the paper relies on primary data sources analyzed with descriptive statistics, GIS techniques and remote sensing. The sections in the paper consist of a review of the major environmental effects and factors associated with the problem as well as mitigation measures in Mali and Niger. The paper concludes with some recommendations. The results point to growing modification along the riverine environments of the Mali and Niger portions of the River Niger Basin due to a host of factors.
Geospatial Information Systems Analysis of Regional Environmental Change along the Savannah River Basin of Georgia
Yaw A. Twumasi,Edmund C. Merem
International Journal of Environmental Research and Public Health , 2008, DOI: 10.3390/ijerph5010054
Abstract: This paper uses remote sensing and geographic information systems (GIS); and descriptive statistics in the assessment of environmental change along the Savannah River Basin of Georgia. Results of the study show that Savannah River basin side of Georgia has been experiencing environmental change due to several decades of relentless pressure induced by anthropocentric activities and host of other socio-economic factors. Normalized Difference Vegetation Index (NDVI) analysis of the area also shows a decline in vegetation cover. The pace of ecological change showed some variations across time and space. Generally, the results point to a decline in water bodies, vegetation, and increase in population, loss of harvested cropland, farms and increasing threats to the environmental systems of the region.
Using Spatial Information Technologies as Monitoring Devices in International Watershed Conservation along the Senegal River Basin of West Africa
Edmund C. Merem,Yaw A. Twumasi
International Journal of Environmental Research and Public Health , 2008, DOI: 10.3390/ijerph5050464
Abstract: In this paper, we present the applications of spatial technologies—Geographic Information Systems (GIS) and remote sensing—in the international monitoring of river basins particularly analyzing the ecological, hydrological, and socio-economic issues along the Senegal River. The literature on multinational water crisis has for decades focused on mediation aspects of trans-boundary watershed management resulting in limited emphasis placed on the application of advances in geo-spatial information technologies in multinational watershed conservation in the arid areas of the West African sub-region within the Senegal River Basin for decision-making and monitoring. While the basin offers life support in a complex ecosystem that stretches across different nations in a mostly desert region characterized by water scarcity and subsistence economies, there exists recurrent environmental stress induced by both socio-economic and physical factors. Part of the problems consists of flooding, drought and limited access to sufficient quantities of water. These remain particularly sensitive issues that are crucial for the health of a rapidly growing population and the economy. The problems are further compounded due to the threats of climate change and the resultant degradation of almost the region’s entire natural resources base. While the pace at which the institutional framework for managing the waters offers opportunities for hydro electricity and irrigated agriculture through the proliferation of dams, it has raised other serious concerns in the region. Even where data exists for confronting these issues, some of them are incompatible and dispersed among different agencies. This not only widens the geo-spatial data gaps, but it hinders the ability to monitor water problems along the basin. This study will fill that gap in research through mix scale methods built on descriptive statistics, GIS and remote sensing techniques by generating spatially referenced data to supplement the existing ones for the management of the Senegal River Basin. The results show the incidence of change predicated on pressures from demography, natural forces and the proliferation of river basin development which resulted in more irrigated areas to meet the needs of the inhabitants of the basin. With the substantial increase in bare surface areas, the basin faces growing exposure to the threats of desertification.
Using Geospatial Information Technology in Natural Resources Management: The Case of Urban Land Management In West Africa
Edmund C. Merem,Yaw A. Twumasi
Sensors , 2008, DOI: 10.3390/s8020607
Abstract: In the past several decades, Lagos Metropolis emerged as one of the fastesturbanizing cities in the West African Sub-region. In the absence of a regular use ofgeospatial information management systems, limited effort had been made to keep track ofchanges in the natural environment in the rapidly growing city for policy making in landadministration. The ubiquitous energy radiated by the rapid urbanization rate in the areanot only created unprecedented consequences by diminishing the quality of theenvironment and natural resources but it raises serious implications for land managementin the region. The factors fuelling the land crisis in the area which are not far fetchedconsists of socio-economic, ecological and policy elements. To tackle these issues in amega city, up-to-date knowledge would be required to capture and analyze landinformation trends. Such an effort will help manage the city’s expansion as well asinfrastructure development through the right choices in planning and (spatial) designsusing the latest tools in geospatial technologies of Geographic Information Systems GIS)and remote sensing. This study investigates the spatial implications of the rapid expansionof metropolitan Lagos for land management using GIS and Remote sensing technology.The result of the research provides a valuable road map that can enable planners contributeto improved land administration necessary for effective management of natural resources.
Geospatial Information Systems Analysis of Regional Environmental Change along the Savannah River Basin of Georgia
Yaw A. Twumasi,Edmund C. Merem
International Journal of Environmental Research and Public Health , 2008,
Abstract: This paper uses remote sensing and geographic information systems (GIS); and descriptive statistics in the assessment of environmental change along the Savannah River Basin of Georgia. Results of the study show that Savannah River basin side of Georgia has been experiencing environmental change due to several decades of relentless pressure induced by anthropocentric activities and host of other socio-economic factors. Normalized Difference Vegetation Index (NDVI) analysis of the area also shows a decline in vegetation cover. The pace of ecological change showed some variations across time and space. Generally, the results point to a decline in water bodies, vegetation, and increase in population, loss of harvested cropland, farms and increasing threats to the environmental systems of the region.
Using Geospatial Information Technology in Natural Resources Management: The Case of Urban Land Management In West Africa
Edmund C. Merem,Yaw A. Twumasi
Sensors , 2008,
Abstract: In the past several decades, Lagos Metropolis emerged as one of the fastesturbanizing cities in the West African Sub-region. In the absence of a regular use ofgeospatial information management systems, limited effort had been made to keep track ofchanges in the natural environment in the rapidly growing city for policy making in landadministration. The ubiquitous energy radiated by the rapid urbanization rate in the areanot only created unprecedented consequences by diminishing the quality of theenvironment and natural resources but it raises serious implications for land managementin the region. The factors fuelling the land crisis in the area which are not far fetchedconsists of socio-economic, ecological and policy elements. To tackle these issues in amega city, up-to-date knowledge would be required to capture and analyze landinformation trends. Such an effort will help manage the city ¢ € s expansion as well asinfrastructure development through the right choices in planning and (spatial) designsusing the latest tools in geospatial technologies of Geographic Information Systems GIS)and remote sensing. This study investigates the spatial implications of the rapid expansionof metropolitan Lagos for land management using GIS and Remote sensing technology.The result of the research provides a valuable road map that can enable planners contributeto improved land administration necessary for effective management of natural resources.
PLGA-Polymer Encapsulating Tumor Antigen and CpG DNA Administered into the Tumor Microenvironment Elicits a Systemic Antigen-Specific IFN-γ Response and Enhances Survival  [PDF]
Kevin P. Nikitczuk, Rene S. Schloss, Martin L. Yarmush, Edmund C. Lattime
Journal of Cancer Therapy (JCT) , 2013, DOI: 10.4236/jct.2013.41035
Abstract:

Critical to the generation of an effective therapeutic antitumor immune response is the elicitation of effective antigen presentation coupled with overcoming tumor-immune escape mechanisms. Towards this end, we aimed to understand the therapeutic effectiveness of a polymer based vaccine approach at enhancing the anti-tumor responses in a tumor-bearing mouse model. While we and others have previously demonstrated the effectiveness of PLGA based systems in delivering antigen etc., studies scarcely focus on understanding the immunological mechanisms of polymer based therapies in tumor bearing treatment models. Considering tumors modulate the immune system and consequently the efficacy of therapies, understanding treatment mechanisms in the presence of tumor will help lead to more efficacious treatment options. We demonstrate here that a poly(lactic-co-glycolic acid) (PLGA) based delivery system encapsulating tumor antigen (OVA) and the TLR9 agonist CpG motif DNA administered into the tumor microenvironment initiates an effective type 1 mediated (IFN-γ producing) anti-tumor response in a syngeneic murine model of T cell lymphoma (E.G7-OVA). Although E.G7-OVA tumors spontaneously generate antigen specific CTLs in draining lymph nodes (LN), tumors progress rapidly. Modulation of the tumor microenvironment via local PLGA based therapy led to the generation of a systemic antigen specific Th1 response, absent in the non-polymer delivery method, subsequently associated with reduced tumor growth and prolongation of survival. These studies provide further insight into the use of a PLGA-based therapeutic approach at modulating the tumor microenvironment and highlight the need for analyzing the treatment effects in a tumor bearing model.

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