Jagath Gunatilake

Pattern of Physical Activity Among Sri Lankan Adults in the District of Colombo A Cross-sectional Study

Physical inactivity is a modifiable risk factor of many non-communicable diseases. The aim of this study was to assess the pattern of physical activity among Sri Lankan adults in the district of Colombo, Sri Lanka. The study was carried out among a sample of 1320 adults aged 20 to 59 years, selected using stratified, cluster sampling method. Physical activity was assessed using the long form of the International Physical Activity Questionnaire validated for Sri Lanka. The prevalence of sufficient physical activity was 82.0% (CI = 78.5-85.0) for males and 79.7% (CI = 76.5-82.6) for females. The odds of having sufficient activity were lower with increase in the level of urbanisation. Activity was achieved mainly through domestic and transport related activity. Only 21.7% carried out at least some activity for leisure. As Sri Lanka continues to urbanize, it is important to find strategies to increase the level of activity especially at leisure.

Development and validation of a tool to assess the physical and social environment associated with physical activity among adults in Sri Lanka

BackgroundEnvironmental characteristics are known to be associated with patterns of physical activity (PA). Although several validated tools exist, to measure the environment characteristics, these instruments are not necessarily suitable for application in all settings especially in a developing country. This study was carried out to develop and validate an instrument named the “Physical And Social Environment Scale – PASES” to assess the physical and social environmental factors associated with PA. This will enable identification of various physical and social environmental factors affecting PA in Sri Lanka, which will help in the development of more tailored intervention strategies for promoting higher PA levels in Sri Lanka.MethodsThe PASES was developed using a scientific approach of defining the construct, item generation, analysis of content of items and item reduction. Both qualitative and quantitative methods of key informant interviews, in-depth interviews and rating of the items generated by experts were conducted. A cross sectional survey among 180 adults was carried out to assess the factor structure through principal component analysis. Another cross sectional survey among a different group of 180 adults was carried out to assess the construct validity through confirmatory factor analysis. Reliability was assessed with test re-test reliability and internal consistency using Spearman r and Cronbachs alpha respectively.ResultsThirty six items were selected after the expert ratings and were developed into interviewer administered questions. Exploration of factor structure of the 34 items which were factorable through principal component analysis with Quartimax rotation extracted 8 factors. The 34 item instrument was assessed for construct validity with confirmatory factor analysis which confirmed an 8 factor model (x2 = 339.9, GFI = 0.90). The identified factors were infrastructure for walking, aesthetics and facilities for cycling, vehicular traffic safety, access and connectivity, recreational facilities for PA, safety, social cohesion and social acceptance of PA with the two non-factorable factors, residential density and land use mix. The PASES also showed good test re-test reliability and a moderate level of internal consistency.ConclusionsThe PASES is a valid and reliable tool which could be used to assess the physical and social environment associated with PA in Sri Lanka.

Web GIS to Identify the Problematic Mobile Signal Clusters

Mobile communications has become one of the fastest growing sectors in the world today. With the technological advancement, mobile communication has subjected to many upgrades such as 2G, 3G, 4G. The question of “Does a customer get the expected capabilities from it?” is not answered yet. Even though, the subscribers of all operators pay almost equal charges per minute, most of the time, they do not get the real benefit from the service. At the moment there is no any location based system to capture the availability of signal receiving levels (specially 3G and 4G signal for Dongles), when a customer sit in front of the marketing person, asking to provide a new connection. What most of the customers do is to use the equipment for few days and return them with a complaint of malfunction in case of signal unavailability. In this study geostatistical analysis was carried out by the method of Inverse distance weighting and the interpolated maps were generated using ArcMap 10. Maps were uploaded to the map server, with standard color ramp. Thereby, the network users can get a better idea about the variation of mobile signal receiving level in a particular location. The developed web based GIS (Geographic Information Systems) system provides the capability of accessing the mobile signal levels remotely in an online manner prior to dealing with a particular customer. Analysis of receiving signal level variation helps to find clusters which have low signal levels than expected. Also, further investigation can be carried out to determine the frequently changing network clusters against a relevant time domain.

Using multiple methods to assess heavy metal pollution in an urban city

Heavy metal pollution in urban cities is now an accepted fact. An understanding of the natural and anthropogenic contributions to heavy metal accumulation in these cities is necessary to develop strategies to mitigate their impacts, particularly on human health. Here, we used multiple records using geological and biological pollution indicators to assess the extent of pollution in the Colombo Metropolitan Region (CMR), Sri Lanka. Elemental concentrations of Cu, Zn, Ni and Pb were determined in four depositories: surface soil (90 samples), canal sediments and canal water (45 samples each) and vegetation (62 samples). These were mapped using GIS overlapping the road network to identify hotspots of heavy metals. While the surface soil, canal sediments and leaves of trees had higher and different amounts than background levels of heavy metals, canal water had low levels. Our results suggest that anthropogenic activities are the major source of heavy metals in an urban city, and unique natural factors, such as coastal conditions, terrain morphology and climate, combine and influence the distribution of these metals. We discuss the possible remediation of metal pollution and the necessity of a holistic multi-proxy approach to understand urban heavy metal contamination in a rapidly populating area.

Evaluation of geomechanical and geochemical properties in weathered metamorphic rocks in tropical environment: a case study from Samanalawewa hydropower project, Sri Lanka

The effect of weathering on changes of physical and mechanical properties of rocks is a prime concern in the perspectives of geology and engineering. These properties have been studied mostly on weathered igneous and sedimentary rocks under humid climates. Studies on weathering of metamorphic rocks, especially under a tropical climate, are rare. This study evaluates change of physical, mechanical, chemical, and mineralogical properties of metamorphic rocks that weather under tropical climatic conditions. Samanalawewa hydropower project area was selected for this study, because rapid weathering of a metamorphic rock (sillimanite garnet gneiss) was observed in the project site. Fresh rocks that are subjected to weathering have reached to completely weathered condition in a time span of less than 25 years in this area. Visually assessed weathering grades were physically and mechanically evaluated using bulk density, equotip hardness, porosity, specific gravity, point load strength, and slake durability tests. Mechanical properties, especially point load strength, change rapidly at the onset of weathering, while chemical properties show significant changes at later stages of weathering. Mineralogical changes such as appearance of secondary minerals are at the latter part of weathering. Physical properties gradually change during weathering. The observed changes in physical, mechanical and chemical properties indicate that their variations during weathering are independent of lithology and climatic conditions.

Fuzzy based binary feature profiling for modus operandi analysis

It is a well-known fact that some criminals follow perpetual methods of operations, known as modus operandi (MO) which is commonly used to describe the habits in committing something especially in the context of criminal investigations. These modus operandi are then used in relating criminals to other crimes where the suspect has not yet been recognized. This paper presents a method which is focused on identifying the perpetual modus operandi of criminals by analyzing their previous convictions. The method involves in generating a feature matrix for a particular suspect based on the flow of events. Then, based on the feature matrix, two representative modus operandi are generated: complete modus operandi and dynamic modus operandi. These two representative modus operandi will be compared with the flow of events of the crime in order to investigate and relate a particular criminal. This comparison uses several operations to generate two other outputs: completeness probability and deviation probability. These two outcomes are used as inputs to a fuzzy inference system to generate a score value which is used in providing a measurement for the similarity between the suspect and the crime at hand. The method was evaluated using actual crime data and four other open data sets. Then ROC analysis was performed to justify the validity and the generalizability of the proposed method. In addition, comparison with five other classification algorithms showed that the proposed method performs competitively with other related methods.

Study of the Urban Green Space Planning Using Geographic Information Systems and Remote Sensing Approaches for the City of Colombo, Sri Lanka

With the growth of human population and their demands, constructed environment has replaced the natural environment in a significant way. Urban forestry, Urban Green Spaces (UGS) and natural parks are very important which urban planners and designers are interested in. This study is focused on the sustainable development of green spaces. Therefore Identification and analyzing of existing urban green areas was done through supervised image classification method by using high resolution satellite images. Central place theory and spatial analytical techniques were combined to understand the existing patterns of the green spaces. The green areas were analyzed with the other critical natural and human factors and weighted under existing urban regulations and standards in Sri Lanka and developed a multi criteria model for analyzing the suitability and probability of expansion of existing urban green spaces for sustainable green space planning activities. The results were presented in cartographical maps as well as web based maps which encourage the citizen engagement activities for nature conservation.

Evaluation of Urban Air Pollution Distribution in the Colombo Municipal Council Area, Sri Lanka

Environmental pollution is one of the major health problems in both industrialized and developing countries including Sri Lanka. The main categories are water pollution, air pollution, land pollution and noise pollution etc. Out of this, air pollution is one of the severe and growing problem in worldwide and highly affects to the human health specially those who live in urban centers. It is a dangerous and silent hazard in comparison to other hazards since it is invisible. There are two types of air pollution respectively indoor air pollution and outdoor air pollution. Mainly indoor pollution is increasing with human domestic activities and outdoor air pollution is increasing with urbanization, industrialization and transport activities. The usage of motor vehicles in the Colombo City has been increased by over 300% in the last 20 years. The majority of these are motor cycles and three wheels and also other vehicles such as public transports. In that case resent results show that the city of Colombo is heavily polluted and the level of air pollution has been reached to its dangerous levels. During peak traffic hours (between 6 am to 8.30 am and 4 pm to 6 pm), Colombo area face to severe air pollution. Air pollution level was increase with rainfall variation of the area. Contamination of air pollutant was travel to another area using wind and Sea breeze. Main air pollutant emitter was Traffic and vehicles. It was clearly shows with monthly variation of pollutant distribution. Air pollution was increased with festival seasons and school holding time period.