University of Peradeniya

About: University of Peradeniya is a education organization based out in Kandy, Sri Lanka. It is known for research contribution in the topics: Population & Poison control. The organization has 5970 authors who have published 7388 publications receiving 197002 citations.

Changing the planting date as a climate change adaptation strategy for rice production in Kurunegala district, Sri Lanka

Abstract: The effect of changing the planting date on the dry season rice yield was simulated by using the software Decision Support System for Agrotechnology Transfer (DSSAT 4.5) for four rice varieties grown in Kurunegala district, Sri Lanka under expected climate change. Daily weather data up to the year 2090 were downscaled to the district from Global Climate Model outputs under the emission scenarios A2 and B2 published by the Intergovernmental Panel on Climate Change using the Statistical Downscaling Model (SDSM 4.2). The DSSAT model was applied to simulate future rice yields from four rice varieties grown in the district under three different planting dates: (1) planting in May—the base condition; (2) advancing the planting date by 1 month, i.e., to June; and (3) planting 1 month earlier, i.e., in April. Results show that the seasonally averaged dry season rice yield would increase compared to the base condition when the planting date is advanced by 1 month and, on the other hand, the seasonally averaged rice yield would decrease compared to the base condition when the planting date is delayed by 1 month for all four varieties under both A2 and B2 scenarios. Advancing the rice planting date by 1 month for all four rice varieties can be identified as a non-cost climate change adaptation strategy for rice production in Kurunegala district.

Upregulation of HIF-1alpha in malignant transformation of oral submucous fibrosis.

Abstract: Background: Oral submucous fibrosis (OSF) is a precancerous condition showing extensive fibrosis of the submucosa and affects most parts of the oral cavity, including pharynx and upper third of the oesophagus. The molecules involved in the biological pathways of the fibrotic process appeared to be either down- or upregulated at different stages of the disease. Despite the precancerous nature, malignant transformation of the epithelium in the background of fibrosis has not been studied in detail. HIF-1 alpha is a known transcription factor that is induced by hypoxia. Aims: To test the hypothesis that hypoxia plays a role in malignant transformation and progression of OSF. Materials and Methods: We used both formalin-fixed and frozen samples of OSF and normal mucosa to investigate the relationship between HIF-1 alpha and epithelial dysplasia using immunohistochemistry and RT-PCR. Conclusions: Our data indicate that HIF-1 alpha is upregulated at both protein and mRNA levels in OSF and the correlation with epithelial dysplasia is statistically significant (P < 0.001). We propose that HIF-1 alpha may play a role in malignant transformation of OSF. Further, over-expression of HIF-1alpha may contribute to the progression of fibrosis. It may be possible to use HIF-1 alpha as a marker for malignant transformation of OSF.

Determining optimal levels of fluoride in drinking water for hot, dry climates--a case study in Sri Lanka.

Abstract: The prevalence of dental caries and dental fluorosis was examined in 380 14-yr-old children living in four geographic areas of Sri Lanka with water F-levels of 0.09-8.0 ppm. A reduction in caries prevalence by 43% was recorded in children consuming 0.6-0.79 ppm F- compared to those in low fluoride areas (< 0.4 ppm). Among those consuming drinking water containing < 1.0 ppm F-, however, 32% of the children had mild forms and 9% severe forms of dental fluorosis (Dean's index). Although other sources of F- may contribute to this effect, the prevalence and severity of dental fluorosis seen in low fluoride areas was confirmed to be high in rural Sri Lanka. Our data are comparable with recent findings from other tropical countries, e.g. Kenya and Senegal, and reaffirm that WHO guidelines for the upper limit of F- in drinking water may be unsuitable for developing countries with a hot, dry climate. Current knowledge now enables us to recommend 0.8 ppm as an appropriate upper limit for F- in drinking water supplies for these populations.

Thermal and baric evolution of garnet granulites from Sri Lanka

Abstract: Garnet granulites from Sri Lanka preserve textural and chemical evidence for prograde equilibration at temperatures of at least 700–750°C and pressures in the vicinity of 6–8 kbar. Associated strain patterns suggest prograde metamorphism occurred during and immediately following an episode of crustal thickening, with the prograde P–T conditions probably reflecting a combination of the conductive and advective transport of heat at the mid‐levels of tectonically thickened crust. The occurrence of prograde wollastonite provides evidence for internally buffered fluid compositions, or fluid absent conditions, during peak metamorphism and precludes pervasive advection of a CO2‐rich fluid. The advective heat component is therefore likely to have been provided by the transport of silicate melt. Intricate symplectitic textures record partial re‐equilibration of the garnet granulites to lower pressures (˜ 4–6 kbar) at high temperatures (600–750°C), and testify either to the erosional denudation of the overthick crust prior to significant cooling (i.e. quasi‐isothermal decompression) or to a subsequent static heating possibly of early Palaeozoic age (Pan‐African). The metamorphic history of the Sri Lankan granulites is compared with high grade terrains in the neighbouring fragments of Gondwana, with the emphasis on similarities with Proterozoic granulites of the East Antarctic craton. Copyright © 1988, Wiley Blackwell. All rights reserved