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Item Modeling and Forecasting Mortality in Sri Lanka(2014) Aberathna, Wasana; Alles, Lakshman; Wickremasinghe, W. N.; Hewapathirana, IsuruThe purpose of this study is to develop sex-specific mortality estimation models using historical mortality data for Sri Lanka, based on the statistical time series techniques attributed to Lee and Carter (1992). Historical mortality data was analyzed in the light of significant historical episodes. Several alternative univariate time series models were examined for modeling males and females, as well as a bivariate vector autoregressive (VAR) model. The VAR model when fitted to the first differenced series performed better than the univariate models and hence used for forecasting purposes. From the estimated VAR model, mortality forecasts were generated for the period up to 2030 and life tables were generated for the selected periods of 2006-2008.Item Change detection in dynamic attributed networks(2018) Hewapathirana, I.U.A network provides powerful means of representing complex relationships between entities by abstracting entities as vertices, and relationships as edges connecting vertices in a graph. Beyond the presence or absence of relationships, a network may contain additional information that can be attributed to the entities and their relationships. Attaching these additional attribute data to the corresponding vertices and edges yields an attributed graph. Moreover, in the majority of real-world applications, such as online social networks, financial networks and transactional networks, relationships between entities evolve over time. Change detection in dynamic attributed networks is an important problem in many areas, such as fraud detection, cyber intrusion detection, and health care monitoring. It is a challenging problem because it involves a time sequence of attributed graphs, each of which is usually very large and can contain many attributes attached to the vertices and edges, resulting in a complex, high-dimensional mathematical object. In this survey we provide an overview of some of the existing change detection methods that utilize attribute information. We categorize these methods based on the levels of structure in the graph that are exploited to detect changes. These levels are vertices, edges, subgraphs, communities, and the overall graph. We focus attention on the strengths and weaknesses of these methods, including their performance and scalability. Furthermore, we discuss some publicly available dynamic network datasets and give a brief overview of models to generate dynamic attributed networks. Finally, we discuss the limitations of existing approaches identifying key areas for future research.Item Leishmaniasis: a vector- born disease in Sri Lanka: past, current and future(Gloria Scientiam – Golden Jubilee Commemorative Volume, Faculty of Science, University of Kelaniya, 2017) Ganehiarachchi, G.A.S.M; Nayakarathna, N.M.N.G.; Rajapakse, R.P.V.J.Leishmaniasis is caused by a protozoan parasite Leishmania species and is transmitted to humans by the bite of infected female phlebotomine (Diptera: Psychodidae) sand flies. There are three main forms of Leishmaniasis; Cutaneous Leishmaniasis, Muco-Cutaneous Leishmaniasis and Visceral Leishmaniasis. At present, Cutaneous Leishmaniasis is established in Sri Lanka. The parasite in this country is Leishmania donovani MON 37 and the prevalent vector is Phlebotomus argentipes. Environmental factors including temperature, humidity and rainfall influence the abundance and distribution of sand flies. Socio-economic conditions, population mobility, environmental and climate changes are the main risk factors of the spread of Leishmaniasis. Early detection of the disease and treatment, vector management and health education are the main control strategies for the control of the disease. It is a timely need to control the disease transmission before more virulent strains are established in the country. To resolve the epidemiology of Leishmaniasis further studies on the parasitic aspects and entomological studies of vector aspects are most important. Harmonizing with these biological phenomena, continuous surveillance, improving case detection programs at the community level and implementing management protocols and control activities are necessary to eliminate Leishmanisis in Sri LankaItem Effectiveness of protected areas in preventing rubber expansion and deforestation in Xishuangbanna, Southwest China(Land Degradation & Development, 2018) Sarathchandra, C.; Dossa, G.G.; Ranjitkar, N.B.; Chen, H.; Deli, Z.; Ranjitkar, S.; De Silva, K.H.W.L.; Wickramasinghe, S.; Xu, J.; Harrison, R.D.Protected areas (PAs) are supposedly key refuges for the world's remaining biodiversity. Our study site, Xishuangbanna, harbors a high proportion of China's biodiversity but is threatened by rapid deforestation and expansion of monoculture rubber. We quantified the success of Xishuangbanna's PAs in preventing deforestation.Most previous analyses of PA effectiveness have insufficiently accounted for biases arising from PA location and establishment, because they overlooked the importance of site‐matching in accounting for landscape change.We used matching methods to minimize such biases in comparing land use conversion rates inside and outside‐PAs. By 2010, Xishuangbanna had 3,455.5 km2 (~18%) designated as PAs. However, rubber occupied 22% of its land area and was expanding at a rate of 153.4 km2/year. Between 1988 and 2010, conventional analysis showed a deforestation rate of 9.3 km2/year. However, matching analysis showed a significantly higher rate of deforestation, 10.7 km2/year, which resulted in the deforestation of ~11% of PA's land. We argue that PAs were less effective than had previously been thought. The situation worsened from 2002 to 2010, when the deforestation rate within PAs was actually higher than that of outside PAs, although this difference was not significant. The designated higher levels of protection in ‘core’ zones were also unsuccessful in preventing deforestation. At current rates, within the next 50 years, a further 16% of PAs would be deforested in Xishuangbanna. This could even be an underestimate, as without intervention, drivers of deforestation tend to accelerate. Therefore, reviewing and strengthening current PA management policies is essential.Item Root-foraging behavior ensures the integrated growth of Vallisneria natans in heterogeneous sediments(Environmental Science and Pollution Research, 2017) Chen, J.; Hu, X.; Cao, T.; Zhang, X.; Xi, Y.; Wen, X.; Su, H.; De Silva, W.; Zhu, T.; Ni, L.; Xie, P.Abstract The present study was carried out to determine the efficacy of root foraging and the physiological response of Vallisnaria natans grown in heterogeneous sediments. V. natans was cultivated in two homogeneous and two heterogeneous sediments. The results suggested that V. natans grown in heterogeneous sediments presented a significantly higher root proportion in its total biomass, exhibited root foraging, and grew well, as indicated by a total biomass, ramet number, and plant height very close to those of plants grown in nutrient-rich clay sediment. Moreover, the more sensitive physiological response of the roots than the stems or the leaves to sediment nutrients suggested that root foraging occurred, and the approached values between the two heterogeneous sediments and the homogeneous clay sediment indicated that V. natans could satisfy its nutrient requirements via root foraging. The results may be useful in the recovery of macrophytes that remodel part (rather than all) of the substrate and can potentially improve habitats that are unsuitable for plant growth.Item Spatial Variation in Trophic Structure of Dominant Fish Species in Lake Dongting, China during Dry Season(Water, 2018) Yu, J.; Guo, L.; Zhang, H.; Xu, J.; Hu, H.; Xue, T; Luo, C.; Yi, C.; Hu, Y.; De Silva, K.; Xie, P.Understanding trophic interactions in food webs is crucial to revealing the transfer of substances and energy from primary food sources to consumers in aquatic ecosystems. We hypothesize that the trophic structure of consumers can be significantly affected by primary food sources (pelagic, benthic, and littoral sources) through complex trophic interactions. This study used stable isotope analysis and Bayesian mixing models to estimate the trophic levels of fish consumers and the contributions of primary food sources in the three sub-lakes (Eastern, Southern, and Western Dongting) of Lake Dongting, which have different physical and chemical parameters of water, fish species diversity, and plankton (phytoplankton and zooplankton) density. Results showed the differences in community structures of fish among sub-lakes. Fish trophic levels were significantly higher in Eastern Dongting than those in the two other areas. The contributions of primary food sources to fishes were as follows: the pelagic source was the main basal food source in Eastern Dongting, and littoral and pelagic sources played equally essential roles in Southern Dongting; fishes in Western Dongting relied on more benthic source to growth than those in the two other regions. This study can fill gaps in our knowledge of the influence of the underlying food available on trophic structure of consumers by exploring the role of primary food sources and making the trophic structure of consumers in the aquatic food web highly complicated and diverse through control of the distribution of primary food sources.Item Substrate characteristics and species diversity of marine angiosperms in a micro-tidal basin estuary on the west coast of Sri Lanka(Sri Lanka Journal of Aquatic Sciences, 2010) De Silva, K.; Amarasinghe, M.Diversity of marine angiosperm species (seagrasses) at Kadolkele in Meegamuwa (Negombo) estuary was studied with a view to understanding the effect of substrate characteristics on diversity. Seagrass samples were obtained along three line transects, laid perpendicular to the shoreline at 20 m intervals. Shannon-Wiener index was used to determine the species diversity of seagrasses in the study site at Kadolkele that was divided into three strata, demarcated by the distance, i.e. 0-10 m, 10-20 m and 20-30 m from the shoreline. Comparison of Shannon-Wiener index values indicated that the diversity of first stratum close to the shoreline was significantly different from that of the other two among which no significant difference was found to occur. Substrate pH, soil electrical conductivity, organic mater content and particle size distribution were measured from the substrate samples taken from each stratum. No statistically significant difference was observed with pH (3.92-6.82) and particle size distribution among the three strata. Soil electrical conductivity and organic matter content of stratum 3 however, was significantly different (p< 0.05) from the other two strata. Kadolkele seagrass bed consisted of two species and Halodule pinifolia (5822 shoots m-2) dominated over Halophila ovalis (1030 shoots m-2). The area adjacent (0-3 m) to the mangroves at the shoreline was devoid of seagrasses and H. ovalis was absent in stratum 1, indicating that substrate characteristics have a marginal effect on the species richness of the seagrasses. Although species richness was similar in the other two strata, higher (Shannon) evenness (0.231), despite the relatively low abundance in stratum 2, contributes to its higher species diversity. Present study therefore documents the subtle habitat partitioning of co-existing marine angiosperm species in a limited area in Meegamuwa estuary.Item High diversity of Ganoderma and Amauroderma (Ganodermataceae, Polyporales) in Hainan Island, China(Mycosphere, 2018) Hapuarachchi, K.K.; Karunarathna, S.C.; Raspé, O; De Silva, K.H.W.L.; Thawthong, A.; Wu, X.L.; Kakumyan, P.; Hyde, K.D.; Wen, T.C.Species of Amauroderma and Ganoderma (Ganodermataceae) have been widely used as traditional medicines in Asia over many centuries. The genera are widely researched, owing to their beneficial medicinal properties and chemical constituents with potential nutritional and therapeutic uses. There are, however, taxonomic confusions surrounding the species in these genera, whose circumscription is often unclear. We surveyed species of Amauroderma and Ganoderma in Hainan Island in Southern China. In this paper, we provide data on 15 species found in the W uzhishan and Jiangfengling mountains on the island. One species named Ganoderma ellipsoideum Hapuar., T.C. Wen & K.D. Hyde, sp. nov. is new to science and introduced with evidence from morphology and molecular analysis. The other species collected are described with photographs and compared with similar taxa. We provide a phylogeny for the two genera based on ITS sequence data and the taxonomic status of the species is briefly discussed.Item Health implications related to mismanagement of domestic and municipal wastewater in Sri Lanka.(Sage Publishers, India., 2011) Najim, M.M.M.; Rajapakshe, I.H.TRADITIONALLY IN SRI LANKAN villages domestic wastewater, especially grey-water generated from kitchens and bathrooms of a household, fl ows along open unlined wastewater drains and is collected in a garden pool known as kohila wala or vegetation pool. This pool is a kind of traditionally constructed wetland. Main vegetation type cultivated in the wetland is kohila (Lasia spinosa) which is used as a leafy and stem vegetable. Medicinal and other important plants are also grown along the drains that utilise the wastewater and its nutrients. This system of grey-water disposal and utilisation was always kept separate from the black-water disposal system as the latter is disposed to individual cesspits located in home gardens. In the traditional sys tem, natural capacity to treat wastewater without any harmful effects to groundwater was possible due to low population density and land availability. With the population expansion in urban centres, the land value increased and land area available for the traditional wastewater treatment process shrank.Item Adapting Sri Lanka to Climate Change: Approaches to Water Modelling in the Upper Mahaweli Catchment Area(Climate Change Research at Universities. Springer, Cham, 2017) Gunawardena, M.P.; Najim, M.M.M.Water flow and water quality changes in surface water bodies due to climate change is a major problem worldwide, typically in river eco-systems. To address these issues, proper monitoring of river flow variations and water quality is necessary, but daily monitoring and data collection is greatly time consuming and costly. Therefore, a study was done with the objectives to calibrate and validate the HEC-HMS 3.5 and HEC-RAS 4.1.0 models to simulate flow variation and water quality variations respectively in Nillambe Oya, Sri Lanka. The development of such models are a significant requirement in the present scientific world to predict river flow and water quality variations as an adaptation for the climate change. The HEC-HMS 3.5 model was used to generate flow which is needed for HEC-RAS 4.1.0. Daily flow data for five years (from October 1991 to September 1996) were used to calibrate the HEC-HMS 3.5 model and another set of daily flow data for five years (from October 1994 to September 1999) were used to validate the model. HEC-RAS 4.1.0 model was calibrated using water quality data collected and analyzed in five days. The validity of the calibrated model was evaluated using water quality data collected in the other four days. The calibrated and validated HEC-HMS 3.5 model reliably predicted the flow in Nillambe Oya. The calibrated and validated HEC-RAS 4.1.0 model simulated Dissolved Oxygen (DO), Biological Oxygen Demand (BOD) and Nitrate Nitrogen (NO3-N) splendidly. Orthophosphates was also predicted reliably by the model, but the simulation of organic Phosphorus was not that sensible.