Joshua M Pearce
email: jpearce@clarion.edu

Sara J Johnson

Gabriel B Grant

Joshua M Pearce Assistant

3DMapping Optimization of Embodied Energy of Transportation

Keywords: ecological education, embodied energy, fuel conservation, greenhouse gas emissions, LEED, mapping, route optimization, transportation energy, transportation

The recent development of Google Earth, an information service that provides imagery and three dimensional data depicting the entire Earth, provides an opportunity to use a new method of navigating information to save energy in the real world. Google Earth uses Keyhole Markup Language (KML) for modeling and storing geographic features and information for display in the Google Earth Client. This paper will analyze the potential of this novel and free geographic mapping service to reduce embodied energy of transportation in two ways. First, at the consumer level, Google Earth will be studied to map the automobile route that uses the least fuel and maintains vehicles at their individual maximum fuel efficiency velocities. The same analysis for single destination trips could be used to optimize fleet vehicle routes such as garbage or recycling collection trucks. The secondary benefit of ecological education will also be explored. Fuel used could be converted into monetary units based on the current price of gas, pollution/ greenhouse gas emissions, or ecological footprints to improve driving habits. Secondly, KML overlays will be analyzed for use of determining: i) raw material and products availability as a function of location, and ii) modes of transportation as a function of emissions. These overlays would enable manufacturers access to an easily navigable method to optimize the life cycle of their products by minimizing transportation embodied energy. The most efficient transportation methods and travel routes could be calculated. This same tool would be useful for architects to obtain Leadership in Energy and Environmental Design rating points for the green design of buildings. Overall, the analysis completed finds that the flexibility and visual display of quantitative information made available by Google Earth could have a significant impact at conserving fuel resources by reducing the embodied energy of transportation on a global scale.

Introduction

Over eighty percent of our global energy needs are met by the combustion of fossil fuels [START_REF] Ristinen | Energy and the Environment[END_REF] and by far the most important type of energy source for the functioning of our global economy is petroleum [START_REF] Yergin | The Prize: The Epic Quest for Oil, Money and Power[END_REF]. Over the past forty years, the number of newlyfound oil reserves has been slowly diminishing [START_REF] Bentley | Global oil & gas depletion: an overview[END_REF]. Some energy analysts warn that globally, society is approaching "peak oil", Joshua M. Pearce, Sara J. Johnson, and Gabriel B. Grant, "3DMapping Optimization of Embodied Energy of Transportation", Resources, Conservation and Recycling, 51 pp. 435453, 2007. where the maximum longterm rate of extraction and depletion of conventional petroleum is reached (although the exact time of peak oil is hotly debated). There are still billions of barrels of oil left underground, and as the price of oil climbs, when supply cannot meet demand, other vast sources of petroleum will become economically exploitable (e.g. Alberta has about 178 billion barrels of proven oil reserves in oil sands (National Energy Board, 2005)). Unfortunately, this does not present a solution, because the emissions from burning these fuels would represent an unacceptable risk to the vitality of the earth because of global climate destabilization and thermal forcing [START_REF] Hansen | Global warming in the twentyfirst century: An alternative scenario[END_REF]Hoffert, et al., 2002;[START_REF] Rose | Global view of solar energy in rational units[END_REF][START_REF] Thomas | Extinction Risk from Climate Change[END_REF]. It is now clear that there needs to be more attention paid to how the fossil fuels are being used, particularly for transportation and more rapid adoption of methods to reduce fossil fuel combustion.

The recent development of Google Earth, a geographical information service that provides satellite imagery and three dimensional (3D) data depicting the entire planet, creates an opportunity to reduce energy consumption for transportation. This paper will explore the viability of this novel and free geographic mapping service to reduce embodied energy of transportation. The embodied energy of transportation refers to the transportation component of the embodied energy, where embodied energy is the quantity of energy required to manufacture and supply to the point of use of a product, material or service. At the consumer level, Google Earth could be used to map the automobile route that uses the least fuel between two locations. It can also be used to optimize fleet vehicle routes in terms of energy and emissions for vehicles such as mail carriers, garbage or recycling collection trucks. This information for transportation energy optimization will help not only conserve fuel, but also can incorporate ecological education features geared toward changing behaviors in vehicle users. Additionally, overlays in Google Earth could be developed first nationally and then on a planetwide basis of i) raw material and product availability as a function of location and ii) modes of transportation as a function of emissions. These overlays would enable manufacturers to minimize the life cycle energy costs of their finished products by access to an easily navigable method to determine embodied energy of transportation for a given product or raw material. This same information could be utilized to develop symbiosis in industrial ecologies. Finally, this information would also be useful for architects trying to reduce the embodied energy in their designs of green buildings.

Background

Physical energy use and resultant emissions from combustion of fossil fuels is steadily becoming of greater importance to decision makers at both macro and micro levels. This is largely driven by the consensus among the 2004 Intergovernmental Panel on Climate Change (IPCC) and the 1993 World Energy Council's Global Energy Scenarios to 2050, that if current trends continue in climate destabilization, our Earth will reach a point of no Joshua M. Pearce, Sara J. Johnson, and Gabriel B. Grant, "3DMapping Optimization of Embodied Energy of Transportation", Resources, Conservation and Recycling, 51 pp. 435453, 2007. return (Hoffert, et al., 2002). Global climate destabilization is primarily due to the combustion of fossil fuels for energy and the resultant greenhouse gas (GHG) emissions (IPCC, 1995;IPCC, 2001). Global warming is already occurring, and if combustion of fossil fuels continues, temperatures are projected to rise 1.4°C to 5.8°C in the next 100 years [START_REF] Penner | The Cloud Conundrum[END_REF][START_REF] Stocker | Models Change their Tune[END_REF]. A rise in temperatures could lead to the melting of glaciated ice sheets, raising the sea level up to 7 meters, and flooding many important coastal cities [START_REF] Gregory | Threatened Lose of the Greenland Icesheet[END_REF]Schiermereier, 2004). Diseases such as cholera, malaria, and dengue fever show correlations to specific climate patterns that would be aggravated by increases in global average temperatures (Kovats, et al., 1999;[START_REF] Koelle | Refractory Periods and Climate Forcing in Cholera Dynamics[END_REF]. Summer heatwaves will also increase (Schar, et al., 2004). An increased temperature will also affect many plants and animals. It is projected that migration routes will change [START_REF] Krajick | All Down hill From Here?[END_REF], the pH levels in the oceans will drop [START_REF] Caldeira | Oceanography: Anthropogenic carbon and ocean pH[END_REF], and extinction rates will increase [START_REF] Thomas | Extinction Risk from Climate Change[END_REF]. Studies have also shown that increased carbon dioxide (CO 2 ) will eventually slow down the nitrogen fixation rates of plants [START_REF] Hungate | CO 2 Elicits Longterm Decline in Nitrogen Fixation[END_REF]. Despite these consequences, CO 2 emissions from the combustion of fossil fuel have consistently been increasing. In the U.S. in 2004, CO 2 emissions from the burning of fossil fuels increased 1.5% (U.S. EPA, 2006). In 2004, the largest source of CO 2 emissions (2,438 Tg (10 6 metric tons) or 43%) came from burning petroleum, the majority of which was used for transportation (U.S. EPA, 2006). The consequences of our continued and escalating fossil fuel combustion for transportation are clearly unacceptable.

Although all aspects of industrialized society currently depend on enormous influxes of fossil fuelbased energy, transportation is now taking a dominant position. As can be seen in Table 1, the relative importance of transportationcaused emissions over the other main enduse sectors (industrial, residential, commercial) has increased from 1990, when the baseline emissions standards were defined for the Kyoto Protocol. Now, transportation makes up the largest percentage, representing one third of all anthropogenic emissions. In 2003, over 27% of the United States' total consumption of energy was used to transport goods and people (U.S. Department of Energy, 2004). This energy, which comes to 26.9 quadrillion (10 15 ) BTUs per year is increasing at an average rate of 1.9% per year (U.S. Department of Energy, 2004).

All current transportation modes result in GHG emissions. The CO 2 emissions from fossil fuel combustion used in transportation for 2004 can be seen in Table 2. Gasoline combustion dominates transportation emissions comprising 60% of the total while diesel combustion and jet fuel combustion produce 23 and 12 percent of the CO 2 emissions respectively. Gasoline and diesel fuel for automobiles have been increasing substantially. Together, they increased from 77% of fuel used to 83% from 1990 to 2004, as can be seen in Table 2. Joshua M. Pearce, Sara J. Johnson, and Gabriel B. Grant, "3DMapping Optimization of Embodied Energy of Transportation", Resources, Conservation and Recycling, 51 pp. 435453, 2007. The physical reality of energy use is often ignored when transportation methods are chosen and thus it is not surprising that the total energy used for transportation from 1990 to 2004 increased by 24% as can also be seen in Table 2. In the past, when humanity governed over what appeared to be an inexhaustible fossil fuel energy supply, and the consequences of its harvest were unknown, it was tolerable to use as much energy as could be extracted economically as rapidly as possible. This is no longer acceptable being that GHG emissions must not increase, but actually be cut to stabilize the global climate. In addition, because energy is needed to fabricate sustainable energy sources such as solar photovoltaics [START_REF] Pearce | Photovoltaics -A Path to Sustainable Futures[END_REF] it appears prudent to try to optimize our use of fossil fuels today. Even small individual reductions in energy use have significant impact when aggregated across the U.S. economy [START_REF] Pearce | Energy Conservation From Systematic Tire Pressure Regulation[END_REF]. One opportunity to resolve these challenges in small steps is to minimize transportation energy for single and multidestination travel routes as well as the embodied energy of transportation in manufactured products. The energy conservation measure studied here is to reduce the embodied energy of transportation by optimizing routes using the Google Earth client.

Material Studied: Google Earth as an Embodied Energy of Transportation Tool Google Earth utilizes Keyhole Markup Language (KML), an Extensible Markup Language (XML) grammar and file format for modeling and storing geographic features, such as points, lines, images and polygons for display in the Google Earth Client. XML is a World Wide Web Consortium (W3C) initiative that allows information and services to be encoded with meaningful structure and semantics that both humans and computers can comprehend. Google Earth contains satellite images of the entire planet as well as topographical information. The resolution of the satellite images is variable, but for some locations the images are so detailed it allows for three dimensional buildings' information. Users of Google Earth can already search for locations and map directions to and from specific locations. The open architecture of the software also allows users to measure distances by creating paths and marking them with customized polygons, utilize their own photos and overlay them upon the provided geographic images, and add specific "placemarks" to locations showing data and links to other sites and files (Google, 2006). The overlays and placemarks serve as a visual Yellow Pages, not only listing the contact information but showing the actual location and directions on a map. Google Earth represents a new way for the information on the internet to be organized by location rather than specific search terms or directories.

Google Earth relays geographic information in an understandable way to average computer users. For example, it allows users to pull up overlays of hotels, restaurants, hospitals, gas stations, schools, and banks over a specific geographic area of interest that are hyperlinked to the establishments' websites and contact information. The applications Joshua M. Pearce, Sara J. Johnson, and Gabriel B. Grant, "3DMapping Optimization of Embodied Energy of Transportation", Resources, Conservation and Recycling, 51 pp. 435453, 2007. for Google Earth are growing rapidly and new programs and overlays are created every day. For example, Google Earth images recently lead to the accidental discovery of an ancient roman villa by a computer programmer [START_REF] Butler | Enthusiast uses Google to reveal Roman Ruins[END_REF]. Google Earth has also been used for creating am interactive map of England's Strategic Health Authorities [START_REF] Boulos | Web GIS in practice III: creating a simple interactive map of England's Strategic Health Authorities using Google Maps API, Google Earth KML, and MSN Virtual Earth Map Control[END_REF] and proved effective at mapping disaster zones during relief efforts in New Orleans and Pakistan [START_REF] Nourbakhsh | Mapping disaster zones[END_REF]. The program is regularly being used by many major television stations including ABC and CNN as an easy method of visually identifying the geographic location of news from all over the globe. One can even track the realtime progress of airplanes, including their altitude and speed (e.g. www.fboweb.com).

Google Earth could also be utilized as an ecological tool. The standard program already includes geographic overlays showing the location of rivers, lakes, mountain ranges, earthquakes, and volcanoes. These overlays could be taken a step further to include pollution data, air quality, radioactive isotope counts, acid rain, ground level ozone, water quality, UV indices, migration paths of endangered species, and local sources of food (farms, community supported agriculture (CSAs), coops, etc). There are already sources of local information about pollution such as www.scorecard.org. In addition, the European Environment Agency has already begun a project entitled "In Your Neighborhood", which will allow the public to view realtime air pollution amounts over various European countries [START_REF] Biever | Will Google Help Save the Planet?[END_REF]. Applications such as these enable users to avoid pollution. By using the power of Google Earth to optimize routes and reduce embodied energy for transportation, users will prevent pollution.

Technique 1: Route Optimization Currently the use of internet mapping software is growing in popularity. Sites such as maps.google.com, maps.yahoo.com/dd, mapquest.com, etc. offer driving directions free of charge for individuals planning trips in the U.S. and abroad. Users type in their current location and destination addresses and a map is formulated with a route and directions for travel. This information is also available for travel software packages and global positioning systems (GPS) to help travelers navigate while driving (e.g. the current model of the Toyota Prius). Currently, the route mapping software is optimized to reduce travel time assuming optimal traffic. Future embodiments could include incorporating traffic and construction delays into routes optimized for time. However, as oil prices continue to climb to record levels and climate change becomes increasingly important in the public consciousness, optimization of routes for fuel use is likely to become more important. Google Earth could be used to assist travelers going to a single destination, to determine the best route, based upon fuel use. Joshua M. Pearce, Sara J. Johnson, and Gabriel B. Grant, "3DMapping Optimization of Embodied Energy of Transportation", Resources, Conservation and Recycling, 51 pp. 435453, 2007. A first approximation for optimizing fuel use in transport is to minimize the distance traveled; however, determining the optimal fuel use for a given route is dependent on several factors: i) distance, ii) type of road, iii) speed, iv) elevation changes and v) type of vehicle and loading of the vehicle. For example, with the exception of fuelelectric hybrid vehicles, traveling at slower speeds from an optimum of around 72 km/hr (45 mph) for a standard automobile can actually decrease mileage. Similarly, the combination of loading and elevation changes can have a profound effect on the amount of fuel needed to transport goods a given distance.

For fleet vehicles, routes can become even more important. Although the embodied energy of transportation from waste recovery and recycling is small compared to the energy used for the entire transportation sector [START_REF] Hunhammar | Cycling residues. Potential for increased transportation demands due to recycling of materials in Sweden[END_REF], numerous studies have been conducted to optimize routes for garbage collection, recycling collection, school bus pickups, etc. [START_REF] Angelelli | The application of a vehicle routing model to a waste collection problem: two case studies[END_REF][START_REF] Ballou | A Continued Comparison of Several Popular Algorithms for Vehicle Routing and Scheduling[END_REF][START_REF] Bowerman | A MultiObjective Optimization Approach to Urban School Bus Routing: Formulation and Solution Method[END_REF][START_REF] Nuortioa | Improved route planning and scheduling of waste collection and transport[END_REF][START_REF] Pattnaik | Urban Bus Transit Route Network Design Using Genetic Algorithm[END_REF][START_REF] Sahoo | Routing Optimization for Waste Management[END_REF][START_REF] Suh | An LCA of alternative wastewater sludge treatment scenarios[END_REF][START_REF] Wang | A mixedinteger linear model for optimal processing and transport of secondary materials[END_REF]. Most of these large fleet vehicles have very low fuel efficiencies and have more polluting diesel engines. There are around 179,000 garbage/recycling trucks in use in the U.S. (INFORM, 2006). These garbage trucks have some of the lowest fuel efficiencies of all motorized vehicles, around 3 miles per gallon (mpg) (2006). Currently, the average truck travels approximately 25,000 miles per year and burns 8,300 gallons of diesel fuel (INFORM, 2006). In the case of fleet vehicle routes, all of the same information would be utilized as in the single destination case, but the route would be optimized for all stops along the path, from the initial to the final destinations. There is extensive, but not exhaustive, use of expensive custom geographic information system (GIS) software to map routes for school buses and garbage trucks. Energy, however, is not always the factor minimized and the tool discussed here offers the possibility of real time overlays being created showing traffic lights and construction zones, which could be modified according to traffic patterns to minimize unnecessary idling of fleet vehicles. An example of this type of overlay can be seen in Figure 1, which shows a Google Earth hybrid satellite photo/street map image of the Borough of Clarion in Pennsylvania. The circles indicate traffic lights. Some "onboard" GPSbased systems already download traffic information in real time, and it is possible these packages could incorporate elevation into their algorithms. These GIS packages, however, are very expensive and an opensource advanced version of the Google Earth tool could be updated in real time to indicate optimal routes based not only on time, but also on energy (or fuel costs).

Results and Discussion for Technique 1:

A. Route and Vehicle Velocity Optimization Joshua M. Pearce, Sara J. Johnson, and Gabriel B. Grant, "3DMapping Optimization of Embodied Energy of Transportation", Resources, Conservation and Recycling, 51 pp. 435453, 2007. In addition to determining the optimal route, using the Google Earth program in vehicles in real time would enable drivers to chart a course that maintains their vehicle at its individual maximum fuel efficiency speed. The operating efficiency of modern automobiles is complex. For a standard automobile powered with an internal combustion engine, the efficiency of the engine improves as it accelerates from rest (0 km/hr), because it uses a fixed amount of fuel to power itself and the accessories, and a variable amount of fuel dependent on the power required to keep the automobile going at a given speed. As the vehicle is accelerated to higher velocities, the automobile overcomes the rolling resistance of the tires and friction in the vehicle's other components (e.g. friction in the wheel bearings). So in terms of fuel used per unit distance, the faster the vehicle goes at first, the better use it makes of that fixed amount of fuel required; however, once the speed gets up into the 80 km/hr (50 mph) range, each increase in speed represents an increase in power required, mostly to overcome wind resistance. Eventually, the power required increases more than the efficiency of the engine improves. At this point, the mileage starts falling and can drop substantially after 88.5 km/hr (55 mph), as can be seen in Fig. 2. For example, a car that decreases its speed from 120.7 km/hr (75 mph) to 105 km/hr (65 mph) is increasing its fuel efficiency by 4.4 mpg. It should be pointed out here that these estimates are conservative because the optimal efficiency as shown in Fig 1 was for cars in 1997. The U.S. automobile fuel efficiency actually declined through the 1990's and is at present relatively level [START_REF] Heavenrich | LightDuty Automotive Technology and Fuel Economy Trends: 1975 through 2006[END_REF]. This is mostly due to the increased use of fuelinefficient sports utility vehicles (SUVs). So although fuel efficiency of cars increased modestly, the increased use of lightduty trucks and SUVs dragged down the combined fuel efficiency of the fleet [START_REF] Heavenrich | LightDuty Automotive Technology and Fuel Economy Trends: 1975 through 2006[END_REF]. Such SUVs and light trucks have i) a drag coefficient about twice that of more aerodynamic cars, ii) more than double the frontal area of small cars, and iii) can weigh two to three times more than cars. In general, smaller, lighter, more aerodynamic cars will get their best mileage at higher speeds than SUVs. Bigger, heavier, more cumbersome and less aerodynamic vehicles will get their best mileage, which is still relatively poor, at lower speeds. The optimal velocity for any given vehicle would change depending on the mass of the cargo it was carrying and the grade and surface the automobile was traveling over. Advanced versions of this technique in future automobiles could include weight sensors and road condition sensors in order to better optimize automobile travel efficiencies.

B. Ecological Education of Drivers

The route optimization tool will have a secondary benefit by encouraging more efficient driving. Already, in some automobiles, there are real time fuel efficiency gauges that encourage better driving habits [START_REF] Mckibbon | My Mileage is Better Than Your Mileage: An allAmerican idea for getting Americans to take gas consumption seriously[END_REF]. For consumers, the Google Earth Transportation Optimization Tool would not only reduce fuel costs, but also enable consumers to better understand the externalities associated with their travel. Gallons or liters of fuel use calculated by the tool could be converted into i) monetary units based on Joshua M. Pearce, Sara J. Johnson, and Gabriel B. Grant, "3DMapping Optimization of Embodied Energy of Transportation", Resources, Conservation and Recycling, 51 pp. 435453, 2007. the current price of gas, ii) pollution based on the emissions tests of the individual vehicle or iii) GHG emissions (e.g. with each gallon of gasoline burned, 19.56 pounds of CO 2 are released into the atmosphere (Energy Information Administration, 2006)). Consumers could have an immediate feedback as to how their trips influenced global climate conditions.

A more intuitive learning aid might incorporate the concept of ecological footprints developed by [START_REF] Wackernagel | Our Ecological Footprint : Reducing Human Impact on the Earth[END_REF]. A transportation method's aggregate ecological footprint is a measure of the productive land area needed to support indefinitely in a sustainable manner all the material input and disposal needs of that transportation mode. Everything that the transportation method consumes (energy in the form of gasoline, materials like lubricants, etc.) has a footprint that can be expressed in terms of land area. For example, a dieselpowered truck could be powered from biodiesel obtained from sustainable agricultural practices on land used to grow switchgrass (Panicum virgatum). The ecological footprint would be the land area needed to grow the quantity of switchgrass to make the necessary amount of biodiesel fuel. In this way, an ecological footprint is a value that represents the amount of resources used in comparison to those that are actually available [START_REF] Pearce | The Mueller Report: Moving Beyond Sustainability Indicators to Sustainability Action[END_REF][START_REF] Chi | Sustainable Transport Planning: Estimating the Ecological Footprint of Vehicle Travel in Future Years[END_REF]. Along with the data, a calculated ecological footprint that represents the amount of resource used in comparison to those available could be mapped on Google Earth. This would allow drivers to "see" how much land area would be needed to fuel their particular trips. For example, using the mileage and efficiency of the average garbage truck in the U.S., the land area needed to sequester the CO 2 emissions from using 8,300 gallons (31,400 L) of gasoline is about 10.99 hectare/year. This ecological footprint area was determined following the method used by [START_REF] Chi | Sustainable Transport Planning: Estimating the Ecological Footprint of Vehicle Travel in Future Years[END_REF]. There are approximately 136,000 of these trucks in the U.S. making the total needed land area about 1.5 million hectare/year. This can be visually displayed in Google Earth as roughly the total land area of Connecticut as seen in Figure 3. It should be noted, that in today's society where the vast majority of diesel used today is not biodiesel using land area as a measure of vehicle fuel requirements may at first appear difficult to comprehend. However, if society is going to make the transition to a sustainable state a shift in the way that standard problems are viewed is necessary. The ecological footprint reference frame provides one such method that can be understood by decision makers because it sets clear limits (e.g. the area of the earth) needed for sustainability to be reached.

Technique 2: Minimization of the Embodied Energy of Transportation of Products

To determine a product's environmental impact, it is necessary to perform a comprehensive life cycle analysis (LCA). LCA quantifies how much energy and raw materials are used and how much (solid, liquid, and gaseous) waste is generated at each stage of a product's life [START_REF] Ayres | Life cycle analysis: A critique[END_REF][START_REF] Pearce | Net Energy Analysis For Sustainable Energy Production From Silicon Based Solar Cells[END_REF]. Ideally, an LCA would Joshua M. Pearce, Sara J. Johnson, and Gabriel B. Grant, "3DMapping Optimization of Embodied Energy of Transportation", Resources, Conservation and Recycling, 51 pp. 435453, 2007. include quantification of material and energy needed for: raw material extraction, manufacturing of all components, use requirements, generation (if any), disposal or recycling, and the distribution/transportation inbetween each stage. Complete LCA's are difficult to perform in part because of the lack of quantifiable data for embodied energy of transportation [START_REF] González | A Fuzzy Logic Approach for the Impact Assessment in LCA, Resources[END_REF]. Here a method is analyzed that utilizes Google Earth to both determine and then optimize the embodied energy from transportation in products.

Using preexisting aerial photography in the (GIS) of Google Earth, specific locations can be pinpointed and overlays containing any type of information can be created. For Google Earth to be used as an ecological navigational tool for manufacture's and consumers, a comprehensive overlay that maps the location of raw materials and products needs to be developed. There should be subcategories within this overlay listing locations of different types of materials. Within each placemark on the overlay, the contact information for each specific manufacture is easily made available. The placemark should also include information about the products and hyperlinks to websites. This will allow consumers to choose the products they want from similar vendors from the locations with the least transportation energy needed.

The interface would work as follows: the consumer would enter what material is needed into a search engine, and the program would then show the product's availability as a function of its location relative to the consumer. This could greatly decrease the embodied energy of transportation of the product. Closer manufacturers would receive the highest ratings. A more advanced version of the program could be developed to calculate the greenhouse gas emissions from transport, producing the most ecologically efficient routes and transport methods. Another easily implemented modification of the Google Earth Transportation Optimization tool would be to encourage consumers to begin to factor in the cost of transportation into their shopping decisions. Google Earth could be used by consumers in finding locations that provide a certain item, check the price of the commodity and then factor that into a cost calculation that would include item cost plus the transportation cost. Consumers could input individual information concerning fuel costs, automobile mileage, depreciation and insurance to personalize the calculation. By providing consumers with exact information regarding the cost of a specific trip to purchase an item the market would operate closer to the ideal and also encourage more efficient consumer travel.

An example can best illustrate the functionality of the overlays needed to determine the optimal location, route and mode of transportation. In this case, the optimal means of transport for obtaining pineapples in Clarion Pennsylvania was chosen as illustration. Although, the pineapple is the 5 th most consumed fruit in the U.S. with an average per Joshua M. Pearce, Sara J. Johnson, and Gabriel B. Grant, "3DMapping Optimization of Embodied Energy of Transportation", Resources, Conservation and Recycling, 51 pp. 435453, 2007. capita consumption of 12.4 pounds per year, it is not grown commercially in Pennsylvania (U.S. Department of Agriculture, 2003). First, Google Earth could be used to input data from the U.S. Department of Agriculture (USDA) to locate the 80 countries and specific geographic areas of the world that produce and export pineapples, which include Thailand, the Philippines, Brazil, China, India, Costa Rica, Nigeria, Kenya, Mexico and Indonesia (USDA, 2003). Next, different transportation methods from each of these locations to Clarion could be analyzed to find the most cost efficient and energy efficient method of obtaining pineapples. The four methods of transport used in this illustration are truck, ship, train and aircraft. Using previously reported efficiency and emissions information from various organizations such as the Department of Transportation and the U.S. Federal Highway Administration, the least emissions route could be chosen.

Results and Discussion for Technique 2: A. Specific Example: Shipment of Pineapples from Hawaii to Clarion, Pennsylvania

To illustrate how this system would function, the transportation of 1 ton of pineapples was simulated from Hawaii, where almost all commercially grown pineapples that appear in the U. S. originate (USDA, 2003). The most and least energy efficient direct routes and modes of transportation were found using Google Earth and can be seen in Fig. 4. Fuel consumption and emissions varies by transportation mode. No consistent fuel efficiency standards could be found because of the wide variation in efficiency between vehicles of the same type. In a completed full version, the fuel efficiencies for each individual vehicle or type of vehicle and carrier would be available to obtain exact quantities of emissions for a given route and mode. The following fuel efficiencies were used here to calculate fuel used and greenhouse gas emissions. Transportation via ship (140 ton miles/gal) when it is possible is the most efficient means, followed by rail (100 ton miles/gal), truck (41 tonmiles/gal) and airplane (5 tonmile/gal) (Congressional Budget Office, 1982).

Based on these average tonmile/gal for different modes, the least efficient route entails flying from Hawaii to Clarion. Please note that indirect routes (e.g. flying first to Atlanta then to Clarion) were ignored. The pineapples would travel 4,683 miles and use 936.6 gallons of fuel. The burning of this fuel releases over 18,000 pounds of CO 2 .

The most efficient route is a little more complicated. First, the ton of pineapples leaves Hawaii via ship and lands in San Francisco, CA. The ship will have traveled 2,388 miles and used 17.1 gallons of fuel. Next, the pineapples leave San Francisco on a singleunit diesel truck to Denver, CO. The truck travels 948.5 miles using 23.1 gallons. Then, from Denver, CO the pineapples traveled the remainder of its journey by train. The train traveled 1466 miles at 14.6 gallons. Thus, overall for this route the pineapples traveled Joshua M. Pearce, Sara J. Johnson, and Gabriel B. Grant, "3DMapping Optimization of Embodied Energy of Transportation", Resources, Conservation and Recycling, 51 pp. 435453, 2007. 4,802.5 miles, only using 54.8 gallons of fuel releasing 523 pounds of CO 2 . In comparison to the least efficient route, the pineapples traveled a further distance but used 17 times less fuel and emissions. It should be noted that the amount of fuel calculated for each leg of the route includes propulsion energy, maintenance energy, vehicle manufacturing energy, construction energy, refinery losses and the energy used for empty movements and for the noncargo weight of vehicles (Congressional Budget Office, 1982). This example ignores the time aspect of using different transportation modes, which is often an important determinant of mode, particularly of perishable agricultural products like pineapples. This time aspect represents a limitation placed on the available modes of transportation for a given amount of goods to be transported. In addition, the costs associated with the different modes of transportation can result in the most energy efficient route being bypassed by the most economically efficient route. The use of Google Earth to at least determine the most energy efficient available routes will assist in reducing the embodied energy of transportation for goods. Although this was a hypothetical example, the ramifications of converting the majority of freight to optimal routes using the Google Earth client could be enormous.

B. Generalized Applications for Manufacturers

For manufacturers this tool becomes even more important as transportation costs become a larger fraction of the manufacturing costs of their products [START_REF] Granahan | As Transportation Costs Surge, Railroads Keep On Truckin[END_REF]. Historically, the transportation costs associated with manufacturing goods have been a relatively insignificant fraction of the final costs of a product. This can be seen by the global nature of the goods in any department store. The costs of transportation energy are so low (aggregate expenditures on freight are only 3.8% percent of trade value in the U.S. [START_REF] Hummels | Towards a geography of trade costs[END_REF]) that other costs govern the location of manufacture. As transportation costs rise due to increases in fuel costs, the optimization of the embodied energy of transportation will become increasingly important for manufacturers that need parts and materials from numerous locations. Manufacturers could use maps produced by Google Earth to locate suppliers at closer geographic locations. Figure 5 shows an example map produced in Google Earth showing the companies in Ohio that manufacture goods from recycled vinyl (The Vinyl Institute, 2006). Both suppliers to the vinyl manufacturers and customers could utilize the maps to find sources for the materials or products that would entail either shorter or less emissionintensive routes.

Over 19 billion tons of freight were transported to and from U.S. businesses in 2002 (Bureau of Transportation Statistics [BTS], 2006). Out of more than 4.4 trillion tonmiles across the U.S., on average any one commodity was shipped 269 miles per ton (BTS, 2006). A relative minority of freight that travel the longest distances make up a large Joshua M. Pearce, Sara J. Johnson, and Gabriel B. Grant, "3DMapping Optimization of Embodied Energy of Transportation", Resources, Conservation and Recycling, 51 pp. 435453, 2007. fraction of the total tonmiles and offer the largest opportunities for reduced emissions. In 2002, only 5% of shipments traveled more than 1000 miles, but this same 5% accounted for more than 1/3 of the total tonmiles (BTS, 2006). The majority of emissions from this transport were from heavyduty road vehicles, which comprised 19% of mobile GHG emissions and 5% of total emissions. Freight railroad and marine vessels combined make up only 1.3% of GHG emissions from all sources [START_REF] Angolson | Assessing the Effects of Freight Movement on Air Quality at the National and Regional Level, Chapter 2: National Freight Transportation and Emissions, prepared for the U[END_REF]. By reducing the distance and emission intensity of the transportation of manufactured goods, GHG emissions can be reduced.

C. Advanced Applications for Manufacturers -Industrial Symbiosis

Google Earth could perform a third function capable of optimizing material and resource consumption in parallel with the embodied energy of transportation by facilitating the creation of industrial symbiosis (IS). "Industrial symbiosis engages traditionally separate industries in a collective approach to competitive advantage involving physical exchange of materials, energy, water, and/or byproducts. The keys to industrial symbiosis are collaboration and the synergistic possibilities offered by geographic proximity" [START_REF] Chertow | Industrial Symbiosis: Literature and Taxonomy[END_REF]. Such a system collectively optimizes material and energy use at efficiencies beyond those achievable by any individual process alone. IS systems such as the web of materials and energy exchanges among companies in Kalundborg, Denmark have spontaneously evolved from a series of micro innovations over a long time scale [START_REF] Ehrenfeld | Industrial Ecology in Practice: The Evolution of Interdependence at Kalundborg[END_REF]; however, the engineered design and implementation of such systems from a macro planner's perspective, on a relatively short time scale, proves challenging. Often, access to information on available byproducts is nonexistent. These byproducts are considered waste and typically not traded or listed on any type of exchange.

Google Earth could provide a GISbased framework for mapping industrial processes, and their associated material and energy flows, to help discover opportunities for by product synergies. Software tools such as the U.S. Environmental Protection Agency's Facility Synergy Tool (FaST) and Bechtel's (now Nexant's) Integrated Material Exchange (IME) Tool have been experimented with on local and regional scales, but have historically been proprietary for a given project. For example, FaST was used for an EcoIndustrial Park Planning Case Study in Burlington Vermont (Industrial Economics, 1998). Although the tool was shared publicly, the much needed industry data was not successfully shared between users. Importunely, FaST is no longer supported and does not run on updated computers. Google Earth is capable of sharing information collaboratively and publicly and does not suffer from geographical restrictions or reliance on commercial software such as Microsoft Access. Joshua M. Pearce, Sara J. Johnson, and Gabriel B. Grant, "3DMapping Optimization of Embodied Energy of Transportation", Resources, Conservation and Recycling, 51 pp. 435453, 2007. Preliminarily, Google Earth can be used to identify processes or production facilities, as it provides a geographical directory of companies that have been "tagged" by Google Earth's open source user community. This functionality is already utilized by Eckelman and Chertow at Yale University in workshop exercises to teach leadership groups how to identify potential synergies. Future work is needed to determine how material and energy flows may be tagged and more sophisticated algorithms can be employed to optimize flows and identify potential byproduct synergies.

D. Generalized Applications for Architects and Designers

The embodied energy for transportation tool would also be useful to architects. Currently, an enormous interest is being taken in Leadership in Energy and Environmental Design (LEED) ratings for buildings. The LEED Green Building Rating System is a voluntary, consensusbased national standard for developing highperformance, sustainable buildings. LEED provides an evolving framework for assessing building performance and meeting sustainability goals. LEED emphasizes state of the art strategies for sustainable site development, water savings, energy efficiency, materials selection and indoor environmental quality (U.S. [START_REF] Green | LEED: Leadership in Energy and Environmental Design[END_REF]. LEED is built on a point (credit) system, where the "greener" and more energy efficient a building is, the more points and the higher level of certification achieved (platinum, gold, silver and 'certification').

Several of the LEED points are based on where a material that makes up the building is manufactured, and this could be facilitated by the database of material locations created for Google Earth. The U.S. Green Building Council (USGBC) gives points for local materials in order to increase demand for building materials and products that are extracted and manufactured within the region, thereby supporting the regional economy and reducing the environmental impacts resulting from transportation (USGBC, 2002). To earn a LEED credit in Materials and Resources (MR) Credit 5.1, a minimum of 20% of a building's materials and products must be manufactured regionally within a radius of 500 miles, where manufacturing refers to the final assembly of the components into the building product that is installed by the tradesmen. For MR Credit 5.2, of the regionally manufactured materials documented for MR Credit 5.1, a minimum of 50% of the building's materials and products must be extracted, harvested, or recovered (as well as manufactured) within 500 miles of the project site. In addition, building designers must establish a project goal for locally sourced materials, as well as identifying materials and contracting with the material suppliers that can achieve this goal. During construction, they must ensure that the specified local materials are installed and quantify the total percentage of local materials installed (USGBC, 2002). Joshua M. Pearce, Sara J. Johnson, and Gabriel B. Grant, "3DMapping Optimization of Embodied Energy of Transportation", Resources, Conservation and Recycling, 51 pp. 435453, 2007. All phases of construction would benefit from having good real time data of resources and recycling sites. For example, aggregate is used in building construction to provide bulk, strength, support and wear resistance. The cost of construction aggregate to the end user is strongly influenced by the cost of transporting processed aggregate from the production site to the construction site [START_REF] Robinson | A GIS analysis of suitability for construction aggregate recycling sites using regional transportation network and population density features[END_REF][START_REF] Robinson | Recycling of construction debris as aggregate in the MidAtlantic Region[END_REF]. Robinson and Kapo completed a geographic information systems analysis for determining construction aggregate recycling sites using existing transportation networks and population ( 2004). This type of work could be integrated into the Google Earth overlays. In addition, for LEED credits MR 2.1 and MR 2.2, building designers must develop and implement a waste management plan and quantify material diversion goals. For credit MR 2.1 they must recycle and/or salvage at least 50% of construction, demolition and land clearing waste and for credit MR 2.2 recycle and/or salvage an additional 25% (75% total) of construction, demolition and land clearing waste (USGBC, 2002).

The USGBC has three goals for recycling and salvaging construction materials: i) divert construction, demolition and land clearing debris from landfill disposal, ii) redirect recyclable recovered resources back to the manufacturing industry, and iii) redirect reusable materials to appropriate sites. All of these goals can be more easily met with a Google Earth overlay of all available recycling and salvage locations. This method can be seen in Figure 6, which is a map created by Google Earth showing the recycling locations in Clarion County, PA and contact information for the various recycling businesses.

Discussion

All of the above suggestions for functionality of the Google Earth Transportation Optimization Tool would reduce energy use. The quantitative savings for each of the suggestions is challenging to predict because the methods are based on compliance of decision makers to utilize specific routes, products, or modes of transportation with reduced embodied energy. Some more environmentallyconscious drivers might alter their driving habits to closely maintain their vehicles optimal velocity, while others might completely ignore this information if it were available. Compliance would vary even for a single decision maker. For example, a decision maker that is late to work is unlikely to reduce speed to save energy and money, whereas that same driver may welcome additional information that will enable him to get to the next gas station when he is running low on gas. Today, in a large part decision makers simply do not have the information available concerning the embodied energy of transportation to make complete decisions. Particularly at the small scale, consumers do not even have easy access to the total costs of transportation in order to make informed rational decisions. The Google Earth Transportation Optimization Tool would correct this information gap and provide a means of significantly reducing energy use. Future research is needed to Joshua M. Pearce, Sara J. Johnson, and Gabriel B. Grant, "3DMapping Optimization of Embodied Energy of Transportation", Resources, Conservation and Recycling, 51 pp. 435453, 2007. quantify the potential savings for each of the methods outlined in this report: personal route optimization, fleet route optimization, optimal vehicle speed, enhanced driver education and information availability, shipping transportation mode optimization, enhanced LCA for products, industrial symbiosis increases and LEED improvements.

Conclusions

This paper completed an analysis of Google Earth, an information service that provides imagery and 3D data depicting the entire Earth, as a novel method of navigating information to conserve travelrelated fuels. First, this paper showed that at the individual driver level, Google Earth could be used to map the route that uses the least fuel between two locations and enable drivers to chart a course that maintains their vehicle at its individual maximum fuel efficiency velocity. This functionality would have a secondary benefit of encouraging more efficient driving by helping drivers better understand the externalities associated with their travel. The data on the fuel used in a trip could be converted into monetary units based on the current price of gasoline to encourage conservation on economic terms or pollution, GHG emission weights, or ecological footprints on environmental/ethical terms. Similarly, the same analysis indicated that Google Earth would be useful to optimize fleet vehicle routes such as garbage or recycling collection trucks. Secondly, overlays in KML of raw material and products availability as a function of location and modes of transportation as a function of emissions could be developed. These overlays would enable manufacturers to optimize the life cycle of their products by minimizing the embodied energy of transportation by calculating the most efficient transportation methods (truck, train, boat, or airplane) and travel routes for finished products and raw materials. These same overlays would be useful for identifying industrial symbiosis opportunities further reducing environmental impact of manufacturing. Finally, Google Earth used in this capacity would also be useful for architects to obtain LEED rating points for the green design of buildings. By utilizing Google Earth as outlined in this paper we can significantly reduce fossil fuel consumed, GHG emissions and overall environmental impacts due to transportation. Joshua M. Pearce,Sara J. Johnson,and Gabriel B. Grant,"3DMapping

Table 1 .

 1 Optimization of Embodied Energy of Transportation", Resources, Conservation and Recycling, 51 pp. 435453, 2007. CO 2 emissions from combustion of fossil fuel by enduse sector for 1990 and 2004 (Tg [10 6 metric tons] CO 2 ) (U.S. EPA, 2006). Joshua M. Pearce, Sara J. Johnson, and Gabriel B. Grant, "3DMapping Optimization of Embodied Energy of Transportation", Resources, Conservation and Recycling, 51 pp. 435453, 2007.

	Tables and Figures
	Enduse Sector	1990	1990 %	2004	2004 %
	Transportation	1,464.4	31%	1,860. 2	33%
	Industrial	1,528.3	33%	1,595. 0	28%
	Residential	922.8	20%	1,166. 8	21%
	Commercial	753.1	16%	983.1	18%
	Total	4,668.6	100%	5605.2	100%

Table 2 .

 2 CO 2 Emissions from Fossil Fuel Combustion in Transportation for 2004 (Tg [10 6 metric tons] CO 2 ) (from U.S. EPA, 2006).Figure 2. MPH vs MPG for a typical American automobile. The graph is based on information published in the Transportation Energy Data Book: Edition 23, Table4.24.

Acknowledgements

We would like to thank our anonymous reviewers who have provided helpful comments on the refinement of this paper.


Christian Jp Unge

Anders Ragnarsson

Anna Mia Ekstrom

Dorcus Indalo

Alice Belita

Festus Ilako Jane Carter

Björn Södergård

The influence of traditional medicine and religion on discontinuation of ART in an urban

Keywords: traditional medicine, religion, drop out, HIV, Kenya

ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

There are specific challenges to sustaining HIV care and treatment programs in informal settlements in sub-Saharan Africa (SSA) given the high mobility, poverty, lack of family support structures, mixed target populations and higher risk behaviors including alcohol and drug use in the populations residing there. However, little research has been conducted on retention in care in African informal settings addressing these challenges [START_REF] Mills | Adherence to HAART: a systematic review of developed and developing nation patientreported barriers and facilitators[END_REF]. A review of 33

African cohort, however none of them in an informal settlement, including over 74,000 patients in 13 countries, found that ART programs had mean retention rates of 79%, 75% and 62% at 6, 12 and 24 months respectively [START_REF] Rosen | Patient retention in antiretroviral therapy programs in sub-saharan Africa: a systematic review[END_REF]. One previous study from an informal settlement in Kenya, found that 29% of the patients discontinued ART (Unge, et al., 2009).

In SSA up to 70% of the population uses traditional medicine as the first line medical care (WHO, 2008). In a study by [START_REF] Babb | Use of traditional medicine by HIV-infected individuals in South Africa in the era of antiretroviral therapy[END_REF] from South Africa, 84% of the patients on ART were at the same time using traditional medicine [START_REF] Babb | Use of traditional medicine by HIV-infected individuals in South Africa in the era of antiretroviral therapy[END_REF]. UNAIDS states that about 60% of people in SSA initially visit a traditional health practitioner for treatment of sexually transmitted infections, including HIV (UNAIDS, 2000). UNAIDS has also developed guidelines for collaboration between traditional and conventional (biomedical) medicine (UNAIDS, 2006).

Collaboration between these two practices has been initiated in many SSA countries but reservations about the results have been raised [START_REF] Nyika | Ethical and regulatory issues surrounding African traditional medicine in the context of HIV/AIDS[END_REF]. The health systems in SSA lack human resources to face the increasing needs to care for people living with HIV (Vassall & Compernolle, 2006) and the World Health Organization (WHO) has since 1974 acknowledged the importance of traditional health practitioners. WHO has also suggested these practitioners become more involved in standard HIV care. The objective of WHO has been to integrate traditional medicine with national health systems, expand the knowledge base on traditional medicine and promote rational use of traditional medicine [START_REF] Homsy | Traditional health practitioners are key to scaling up comprehensive care for HIV/AIDS in sub-Saharan Africa[END_REF].

Besides traditional medicine, religious activities and beliefs are important components for many people in SSA. In Kenya, 75-80% of the population is Protestant or Catholic, 10% are Muslims and 10% belong to various indigenous religions (PEPFAR, 2007). The use of spiritual healing is not well studied but important to many people in Kenya and significant as part of sexual transmitted disease management in Nairobi [START_REF] Kusimba | Traditional healers and the management of sexually transmitted diseases in Nairobi, Kenya[END_REF].

Despite the widespread use of traditional medicine and the vast importance of religion on the lives of many people, little is known about its influence on discontinuation of ART in SSA (Wanyama, et al., 2007).

The objective of this study was to explore the influence of traditional medicine and religion on discontinuation of ART in an urban informal settlement in Nairobi, Kenya.

Methods

Setting

This study was conducted in one of Africa's largest urban informal settlement, Kibera, in Nairobi, Kenya. Kibera is the home to 500,000-1,000,000 people. Poverty and unemployment is widespread and most people work in petty trade or as casual laborers [START_REF] Gulis | Health status of people of slums in Nairobi, Kenya[END_REF]. There are many churches and several mosques in Kibera as well as numerous traditional health practitioners.

In 1998, a community-based health clinic was established by the African Medical and Research Foundation (AMREF). Since February 2003, the centre has been providing free HIV treatment, care and support to Kibera residents. By September 2009, the clinic had enrolled 1575 patients on ART.

Explorative study

An explorative study was conducted in September-October 2008 (unpublished results), in which factors influencing discontinuation of ART were explored using semi-structured interviews with people living with HIV (10 patients) who had withdrawn from the AMREF ART program. The findings from these interviews were discussed in focus group discussions with health care staff at the Kibera clinic (25 staff members in total) (table 1). Due to the focus of this paper these findings will not be discussed in detail. The two main factors influencing retention in care that emerged from this explorative study were traditional medicine and religious issues; therefore we decided to focus on these main topics through another set of semi-structured interviews. English by AB soon after the interviews. CU reviewed the transcribed interviews and the interviews were then discussed with AB and clarifications made when necessary.

F

Twenty-five patients were asked to participate, five declined with no reasons stated. Twenty semi-structured interviews were conducted between March and April 2009 (table 2) that had discontinued the AMREF ART program due to reasons known to be related to traditional medicine and/or religion.

Data analysis

All the data were analyzed using a qualitative latent content analysis [START_REF] Elo | The qualitative content analysis process[END_REF]. The transcribed interviews were read numerous times to get a general idea of the material and to discuss the essential characteristics of the text. Coding and categorization were performed in several stages by the first author together with the other co-authors to get better inter-rater reliability. Key words and selected sentences were identified in the text and labeled with codes in the margins. The codes were further compared and grouped together into sub-categories. Finally the sub-categories were compared, regrouped and merged together into more analytical categories [START_REF] Elo | The qualitative content analysis process[END_REF]. The results were divided into factors patients felt they could influence and those they could not influence, as outlined in the conceptual framework (figure 1).

Ethical approval

Ethical approval for this study was obtained from the Kenya Medical Research Institute.

Results

The influences of traditional medicine and religion on discontinuation of ART were explored and divided in to four main categories: 1) Patients' firm belief in traditional medicine compared to biomedical medicine; 2) Faith, praying and religious practices; 3) Attitudes from church/pastor and 4) Trigger events. The interviewees described a decisional process prior to actual withdrawal from the ART program that involved a trigger event, i.e. a specific event that influenced them to make the actual decision to stop ART.

All patients were living under extremely poor conditions, struggling to find food, overcoming stigma and finding it difficult to disclose their status. Many had been diagnosed with HIV at a late stage, often already showing signs of AIDS. Several of the women were widows and in many cases their husbands had died of AIDS having started ART too late or completely refused treatment at the time of diagnosis. Traditional medicine and religion were key elements in all the interviewees' lives even before being HIV positive and continued to be so also after ART initiation. An important aspect was the fact that the use of traditional medicine, prayers and other religious practices were perceived as factors that the patient could control as compared to many other factors that patients experienced during ART that were perceived to be beyond their individual control, as presented in the conceptual framework (figure 1). Another important finding was that in the minds of the patients, traditional medicine was related to cure and religion was linked to the possibility of getting healed. Both cure and healing were interpreted as the eradication of HIV infection.

Patients´ firm belief in traditional medicine compared to biomedical medicine The possibility of getting cured by taking traditional medicine was raised as a reason for taking traditional medicine instead of ART (quote 1, table 3). The patients described traditional medicine as something within their own control, something they could choose to take or not.

Many patients had taken traditional medicine or sought a traditional health practitioner for care since childhood and this was their usual way of seeking health care.

None of the patients interviewed in this study felt they could discuss traditional medicine openly with the staff at the AMREF clinic. The staff told the patients to never mix ART and traditional medicine and this message was well known to all interviewees. On the other hand, most respondents described how they were strongly encouraged to take traditional medicine by family members or friends (quote 2). Some of the interviewees were even forced by family members to stop ART and start traditional medicine (quote 3). The patients thus had to make one out of three possible decisions: continue taking ART and ignore traditional medicine; take traditional medicine and stop ART; or taking both at once. None of the respondents had revealed their use of traditional medicine to the health care staff at the HIV clinic.

Faith, praying and religious practices

Religious practices were described at two levels: one personal, related to the amount of praying, and, a second more formal level, linked to religious rituals and visits to different religious institutions. Both of these levels were perceived as being within the control of the patient. Many respondents had a firm belief in God's power to heal them and get rid of the disease. Even patients with deteriorating health often believed that if they prayed more and had more faith in God, they would eventually be guided and helped (quote 4). Many interviewees seemed to doubt 12 the effect of ART while they strongly believed in prayers. These patients often referred to stories they had heard or people they knew who had bad experiences of ART (quote 5).

Attitudes from church/pastor

Since almost all the patients in our study reported going to church or a mosque regularly, the influence of pastors/imams and church/mosque elders was of great importance when facing the challenges surrounding HIV and ART. Some patients expressed fear of the priests' reaction to them being HIV infected (quote 6). Some of the interviewees had seen fellow members of the church being expelled after disclosing their status. The ones that had disclosed their status had sometimes faced negative reactions from pastors and church elders and some had even been forced to leave their congregations.

Trigger events

Almost all patients described an event that made them decide to stop ART. Often it was meeting with a person who influenced them to discontinue the ART (quote 7). The trigger event was often a religious event, for instance a prayer meeting (quote 8). Often a friend who had positive experiences from praying inspired the patients to discontinue ART (quote 9).

Discussion

Traditional medicine has previously been found to be an important factor for low adherence to ART in many African countries [START_REF] Dahab | That is why I stopped the ART": patients' & providers' perspectives on barriers to and enablers of HIV treatment adherence in a South African workplace programme[END_REF] but to our knowledge the relationship between traditional medicine/religion and antiretroviral treatment discontinuation has not been studied.

Our study among urban slum dwellers in Kibera, Kenya, showed that many of the interviewees believed that traditional medicine and/or religion would cure the HIV infection, while ART, at best, would only prolong life. Some even thought that ART could cause premature death.

Most patients in our study reported having tried traditional medicine to get cured from HIV. At the same time, many seemed to know that herbal medicines are less efficient than ART in fighting HIV and that they should not be mixed. Counseling patients to not mix ART and traditional medicine appeared to be contra-productive in this setting. Patients used to taking traditional medicine since childhood might switch from ART to traditional medicine when experiencing side effects or when opportunistic infections occur. These treatment interruptions, not supervised by trained health professionals, could lead to development of resistance due to half-life differences of antiretroviral drugs. The treatment interruptions we noted as a result of the do not mix message could be a more serious threat to public health than possible, but yet unknown, drug interactions between ART and the traditional medicine used in the Kibera slum.

When treating, or counseling patients for any disease, it is important to take the widespread use of traditional medicine into account [START_REF] Babb | Use of traditional medicine by HIV-infected individuals in South Africa in the era of antiretroviral therapy[END_REF]. Since all the patients interviewed in this Many interviewees in our study stopped ART and took up praying instead since, as they expressed it, they saw a chance of getting healed through God. When struggling with the challenges related to ART, such as side-effects, enhanced feelings of hunger, and stigma, many chose to put, as they said, their lives in the hands of God, trusting he would make them better or even cure them of HIV infection. Since religion is such an important part of many patients' lives, religious discussions should be included in the day-to-day work of the clinic. Another key issue in this setting is discussion with church representatives about the effects of negative attitudes towards positive HIV status and the importance of taking the ART.

For almost all patients, the final decision to discontinue ART needed a trigger event in this study.

We defined a trigger event as an event or a person that influenced the patient fundamentally, something the patient could describe in detail even years later. In many cases it was a friend or a family member who persuaded or inspired the patient to go for traditional medicine or prayers instead of ART. A trigger, or a cue, is a component present in general theories of motivation and change such as the Wellness Motivation Theory [START_REF] Fleury | Empowering potential: a theory of wellness motivation[END_REF] and the Trans theoretical Model of Change [START_REF] Prochaska | The transtheoretical model of health behavior change[END_REF]. Trigger events are also part of an HIV-specific theory, as proposed by Enriques et al [START_REF] Enriquez | Successful adherence after multiple HIV treatment failures[END_REF]. After a trigger event the patients break their non-adherent behavior. In order for this to happen a process containing five components need to occur: The patients' attitudes towards the treatment need to change, the patient should find the right health care provider, create a support system, gain 15 control over life and form goals [START_REF] Enriquez | Successful adherence after multiple HIV treatment failures[END_REF]. In this theory [START_REF] Enriquez | Successful adherence after multiple HIV treatment failures[END_REF], trigger events are assumed to initiate positive health behavior change [START_REF] Nordqvist | Assessing and achieving readiness to initiate HIV medication[END_REF]. In our study, however, trigger events led to discontinuation of ART and the move to traditional medicine or religion instead of a positive health behavior change.

The importance of collaborating with faith leaders in order to retain patients in ART programs have been raised by other researchers [START_REF] Roura | Driving the devil away": qualitative insights into miraculous cures for AIDS in a rural Tanzanian ward[END_REF]. Our study emphasizes the need for health care staff to have a dialogue with patients, and, if possible faith leaders, about having a religious belief while still taking ART.

In SSA, many patients are diagnosed at a very late stage of HIV infection when signs of AIDS are already evident. Late initiation of ART in many low-income countries is a major factor for early AIDS-related mortality [START_REF] Stringer | Rapid scale-up of antiretroviral therapy at primary care sites in Zambia: feasibility and early outcomes[END_REF]. This seemed to be the case for several of our interviewees' husbands who died soon after ART initiation, leaving the women alone to face enormous challenges taking care of children, providing food and, at the same time, fighting their own HIV disease. The late diagnosis -and thus late initiation of ART -probably also influenced attitudes towards ART negatively among the patients in Kibera. According to this study the interviewed patients did not perceive ART as treatment that increased survival, something that traditional medicine and praying were believed to do.

As shown in the conceptual framework (figure 1), according to the interviewees the process from ART initiation to discontinuation was influenced by numerous factors. These could be divided needed to somehow get control of their lives before being committed to adhering to the ARV treatment and to stay in the program, something that can be challenging when living in a difficult context like this. This need for control to increase adherence has been previously found in other studies [START_REF] Sodergard | A structural equation modeling approach to the concepts of adherence and readiness in antiretroviral treatment[END_REF]. Interventions to decrease discontinuation of ART need to focus on the factors that the individual can control, such as the time of diagnosis, by encouraging people to get tested for HIV. Patients initiating treatment should be informed about the possible side effects they could experience. There is also need to influence attitudes towards ART in the community so that patients understand that initiating ART treatment too late may result in the treatment not being effective. It is important to review the information provided at the clinic concerning traditional medicine, as well as having encouraging open dialogue about religious issues.

Social desirability could have influenced the respondents to say things they believed the interviewer wanted to hear. However, measures were taken to limit the risk of such bias. None of the persons carrying out the interviews were AMREF staff and since negative comments were made about the ART program we believe social desirability was limited. It could also be the most motivated patients who accepted to participate in the study and selection bias cannot be ruled out, but we believe that this did not influence the findings since most patients approached accepted to participate in the study. The reason so few men were interviewed was partly a reflection of reality since the ratio of women to men followed at the clinic is 2:1 (unpublished data from an ongoing study). Another possible reason was that women were more motivated to participate, according to the community health care workers.

Conclusion

Discontinuation of ART could be reduced if ART providers become better at acknowledging and addressing the importance of religious issues and traditional medicine in the lives of patients, especially in resource-poor settings where stigma, poverty and lack of food and social support are key elements in the lives of HIV patients. An open, non-judgmental, discussion around patients' beliefs and practices as part of standard counseling would make patients more comfortable to discuss doubts with the staff before discontinuing ART. Patients should be informed that some traditional medicine is possible to combine with ART and that religious beliefs are not in contradiction with ART. Peer groups could be used to prepare patients for common trigger events that have caused others to discontinue treatment. Counseling patients not to mix ART and traditional medicine appeared to be counter-productive in this setting since patients are used to taking traditional medicine and might switch from ART to traditional medicine when experiencing side effects or when opportunistic infections occur. Further research is needed on the possible interactions between commonly used traditional medicine and ART.

F

  The influence of traditional medicine and religion on discontinuation of ART in an urban informal settlement in Nairobiof traditional medicine as part of standard counseling, may prevent drop-out from ART when side effects or opportunistic infections occur.Key words: traditional medicine; antiretroviral therapy; ART; religion; drop out; HIV; Kenya; Kibera; urban informal settlement; slum; AMREF

  could not discuss traditional medicine with the staff at the clinic, the importance of open discussions regarding this topic cannot be over-emphasized.

  the patient's control and factors that were perceived as outside the control of the patient. Several factors, like food-deficit or the ART side effects were perceived by the patients as being outside their control. On the other hand, what church to attend or what ARV clinic to choose, lies within the control of the patient. According to the patients in this study they

Table 1 .

 1 The main factors influencing discontinuation/retention in care, as stated both by patients and staff at the AMREF clinic.

	• Support from church/faith
	• Healing and traditional medicine
	• Support from health-staff o r • The preservation of own and family's health
	• Bad attitude among health staff P • Stigmatisation in society
	• Food insufficiency e r e • Side effects
	R e v i e w
	O n
	l y
	18

Table 2 .

 2 Demographics of patients having discontinued antiretroviral treatment due to reasons related to traditional medicine and religion from the AMREF clinic, Kibera, Nairobi, Kenya.

	P# Age Sex Tribe	Civil status	Religion	Work
	1	28 F	Luo	Married	Protestant Unemployed
	2	36 F	Kisii	Widow	Catholic	Business
	3	40 F	Luo	Widow	SDA*	Unemployed
	4	40 F	Kamba Widow	Protestant Business
	5	27 F	Luo	Single	Protestant Business
	6	29 F	Luo	Married	Protestant Unemployed
	7	40 F	Nubian Divorced	Muslim	Unemployed
	8	44 F	Luya	Widow	Protestant Unemployed
	9	28 F	Luya	Married	Muslim	Unemployed
	10	52 M	Luya	Married(Polygamos) Protestant Herbal shop
	11	40 F	Luya	Separated	Muslim	Business
	12	40 F	Luo	Widow	Protestant Business
	13	32 F	Luya	Married	Protestant Unemployed
	14	37 M	Kisii	Married	SDA*	Security
	15	50 F	Kamba Widow	Catholic	Business
	16	36 F	Luya	Widow	Catholic	Unemployed
	17	43 F	Luo	Married	Protestant Business
	18	37 F	Luo	Widow	Catholic	Unemployed
	19	32 F	Luo	Widow	Protestant Hairdresser
	20	36 M	Meru	Married	Protestant Watchman
	*SDA=Seventh Day Adventist

Table 3 .

 3 Categories and quotes from the interviews with patients discontinuing antiretroviral treatment in the Kibera slum due to reasons related to traditional medicine and religion.(5) I stopped using the ART because of prayers. Also because I have two other friends that are HIV-positive but one died yet she was using ART, I do not know what was wrong that made her die. I am not using ART, I just pray and I am alive and well. (P 11) I have not disclosed to any priest because they always come and go. They are usually transferred; they are not permanent. There are some church elders but they are not that perfect. You may tell them, but they may end up announcing it to the church or to other people. Even with the priest you have to weigh the option and see if he can keep your secret and He (a friend) was also HIV positive and so when he was taking the traditional medicine and saw the changes, he told me. So he is the one who made me stop taking the ART because I saw the changes and he was much better and healthier than before. (P 18) (8) They said that those who are infected with HIV are healed. They also said that those who were in that meeting and were using the ART should stop because they are healed. (P 13) (9) I saw a friend of mine who had gone for prayers somewhere. She explained to me and asked me to go for prayers with her. I followed her and I saw people who were being prayed for and they even stopped using ART. I then decided to do as they were doing. (P 9) Conceptual framework. Factors influencing the patients' decision to discontinue ART.

	Category	Quotes (#)
	Patients´ firm belief in	(1) If you use them (herbs) properly there is a possibility of getting cured
	traditional medicine	… According to what I have heard about the ART it is possible that the
	compared to	viral load might be undetectable but still the virus will be in the body. (P
	biomedical medicine	2)
		(2) I was living with my grandmother who is a herbalist. She told me to
		use the herbs because they are safer than the other medicine. She said the
		ART have chemicals that affect the body but the herbs are natural. (P 5)

(3) My mother forced me to use the traditional medicine ... She just told me to use the traditional medicine because it is good ... She told me that she gives the herbs to other people and they get well ... I told her that I was using ART but she told me to stop and use the herbs. (P 6) Faith, praying and religious practices (4) Even if one uses medication but they do not believe in God they cannot get well. I believe that God is capable of healing any person whether they are using medication or not. I would rather believe in God and go on with my life and take care of my children … Prayer only is enough. When I was very sick I was prayed for and I even got better before I started taking ART. Even if I did go to hospital, I believe that the prayers helped. Even those that pray do go to hospital. (P1)

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UNAIDS (2000). Collaboration with traditional healers in HIV/AIDS prevention and care in sub-Saharan Africa A literature review. http://data.unaids.org/Publications/IRC-pub01/JC299-TradHeal_en.pdf UNAIDS (2006). Collaborating with Traditional Healers for HIV Prevention and Care in sub-Saharan Africa: suggestions for Programme Managers and Field Workers. Unge, C., Sodergard, B., Ekstrom, A. M., Carter, J., Waweru, M., Ilako, F., et al. (2009).

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