Showing papers in "Journal of The National Science Foundation of Sri Lanka in 2010"

Effect of land use in the upper Mahaweli catchment area on erosion, landslides and siltation in hydropower reservoirs of Sri Lanka

Abstract: A number of multipurpose reservoirs have been impounded in the Upper Mahaweli Catchment (UMC) mainly to generate hydropower, which contributes to about 40-50% of the total hydropower production in the country. The natural forest cover of the UMC has been gradually decreased during the last two centuries due to the large-scale deforestation for plantation agriculture. Subsequently, the forest cover in the hill country has been reduced further to a few isolated patches in order to meet the demand for agriculture, developmental activities and human settlements. Today, vegetables are grown extensively on the steep slopes of the UMC without proper land management practices. Consequently, this agriculturally active land is exposed to severe soil erosion and landslides, in parallel with the rapid rate of deforestation. Estimates of the rate of soil loss on hill slopes and sediment yields in the fluvial system of the UMC indicate that the human-mediated activities in the UMC have increased rates of ongoing erosion by > 100 times over the background rates of natural erosion. Thus, the river Mahaweli and its tributaries carry enormous amounts of sediments during the rainy seasons, both as bed and suspension loads downstream and large amounts are deposited in the multipurpose reservoirs leading to a reduction of their storage capacities. Siltation in hydropower reservoirs could pose a serious threat, leading to the reduction of hydropower generation in the country and a worsening situation could be anticipated in the future. Therefore, proper management of the land by minimizing the in-situ erosion and preserving the detached soil within the catchments through effective conservation measures need to be implemented in order to ensure a steady and continuous power supply from the hydropower resources.

Adaptation of agricultural crop production to climate change: A policy framework for Sri Lanka

Abstract: Agriculture is one of the key sectors of the Sri Lankan economy, which contributes a significant percentage to its gross domestic product (GDP) and provides direct or indirect employment to a sizeable proportion of its population. Climate change involves long-term slow changes in climate, short-term year-to-year climatic variability and unpredictable extreme climatic events. Agriculture, especially crop production, is highly dependent on the prevailing weather conditions and therefore is highly sensitive to climate change, both short-term and long-term. Almost all General Circulation Models predict that the processes of climate change such as increasing atmospheric concentrations of greenhouse gases and global warming will continue well into the 21st century even if the mitigation measures to minimize the causes of climate change exert maximum effect. Therefore, it is imperative that a well-co-ordinated and sustained effort is set in motion to increase the capacity of Sri Lankan agriculture to adapt to short and long-term climate change. Adaptation involves measures to minimize the impacts of climate change. At present, implementation of climate change adaptation measures in Sri Lanka is piecemeal and lacks co-ordination and direction. Hence, a clear policy framework identifying the measures to be pursued and the roles of different stakeholders is needed for allocating and channelling the necessary financial and human resources for successful adaptation to climate change. A clear and comprehensive policy framework also becomes the basis for development of an effective road map and an action plan to achieve successful adaptation. This paper discusses a policy framework for adaptation of Sri Lankan agriculture to climate change based on the following components: (a) Quantification and forecasting of climate change; (b) Assessment of impacts and vulnerability to climate change; (c) Identification and formulation of responses to adapt to climate change; (d) Creating and strengthening the institutional framework and infrastructure to implement and monitor adaptation measures to climate change. Major advances in scientific research on components a, b and c, both locally and internationally, are briefly discussed and key policy measures to facilitate and accelerate their progress along with the relevant stakeholders are identified. Importance of allocating adequate resources to promote research on all aspects of climate change and their impacts by developing infrastructure, a critical mass of experts and an institutional framework to effectively link all stakeholders to channel the formulated adaptation measures to the farming communities at the grass-root level are emphasized. Keywords: Adaptation, climate change impacts, policy, rice, tea, vulnerability J.Natn.Sci.Foundation Sri Lanka 2010 38 (2):79-89 Doi: Normal 0 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} 10.4038/jnsfsr.v38i2.2032

Antineoplastic activity of acetone semicarbazone (ASC) against Ehrlich ascites carcinoma (EAC) bearing mice

Abstract: : Acetone semicarbazone (a Schiff base) has been synthesized and characterized. Its antineoplastic activity has been studied against Ehrlich ascites carcinoma (EAC) cells in Swiss albino mice by monitoring parameters like tumor weight, survival time, tumor cell growth inhibition and haematological characteristics. It was found that the compound at dose 2.0 mg/kg/day i.p (intra peritoneal) significantly decreases tumor weight, increases life span and reduces tumor cell growth rate in comparison to those of EAC bearing mice. The compound also alters the depleted haematological parameters like red blood cells (RBC), white blood cells (WBC), haemoglobin (Hb) % and differential counts (i.e. lymphocytes, neutrophils, monocytes) of EAC bearing mice towards normal. The compound enhances the number of macrophages in normal mice. The toxic effects of the compound on the host are not very high and the host recovers gradually towards normal within a few days after treatment. The compound can therefore be considered as a new potent antitumor agent. The efficiency is more or less comparable to that of a standard drug like bleomycin (0.3 mg/kg/day, i.p.). Keywords: Acetone semicarbazone, antineoplastic activity, EAC cells, haematology. Doi: 10.4038/jnsfsr.v38i4.2649 J.Natn.Sci.Foundation Sri Lanka 2010 38 (4):225-231

Performance of neural networks in forecasting daily precipitation using multiple sources

Abstract: The effectiveness of neural network based models in forecasting daily precipitation, based on ground level measurements obtained from a cluster of weather stations in the dry zone of Sri Lanka, is presented. The implemented networks were based on a feed-forward back-propagation technique. A cluster of ten neighbouring weather stations having 30 years of daily precipitation data (1970 - 1999) was used in training and testing the models. Twenty years of daily precipitation data were used to train the networks while ten years of daily precipitation data were used to test the effectiveness of the models. One model was developed to forecast the precipitation occurrences such as 'rain' or 'no rain', while another model was developed to predict the amount of precipitation at several sub levels using fuzzy techniques. Overall, the models were able to predict the occurrence of daily precipitation with an accuracy of 79 ±3%. Only the nearest neighbours contributed to improving the accuracy of predictions. In the dry zone, the accuracy of predicting the dry days was superior compared to predicting wet days except during the rainy season. Fuzzy classification produced a higher accuracy in predicting 'trace' precipitation than other categories.

Monostome cercariae induced malformations in amphibians: effect of infection at the pre-limb-bud stage tadpoles of Polypedates cruciger Blyth

Abstract: Global biodiversity loss and disease emergence are interrelated and have become a challenging environmental issue. Infection by the digenetic trematode, Riberioa ondatrae induces malformations in amphibians and is considered an emerging infection. The effect of infection on amphibians is not only parasite and host species specific, but also depends on the timing of infection. Recent evidence suggests that infection by cercariae of a monostome trematode species induces severe malformations in the common hourglass tree frog, Polypedates cruciger Blyth (1852) when exposed at the limb-bud stage of development. The aim of this study was to examine whether infection by this treamtode species at the pre-limb-bud stage also induces malformations in P. cruciger . Infection at the pre-limb-bud stage resulted in malformations (64.5%) and significantly reduced survival (77.5%). It also affected the growth and lengthened the larval period. Infections acquired at the pre-limb-bud stage caused a higher mortality and induced fewer malformations than infections at the limb-bud stage, as reported in a previous study. Hence, the effect of infection of monostome cercariae seems to depend on the developmental stage at which the tadpoles are exposed. Understanding the stage specific dynamics of malformations and associated mortality might be important to amphibian conservation. Keywords : Amphibians, Polypedates cruciger , frog malformations, trematode infection. Doi: 10.4038/jnsfsr.v38i4.2651 J.Natn.Sci.Foundation Sri Lanka 2010 38 (4):241-248

Rapid HPLC/UV method for analysis of urinary and plasma/serum paracetamol concentrations

Abstract: Paracetamol is one of the most commonly used over-the-counter pain relievers and fever-reducers. However, overdosing of paracetamol causes liver damage which may lead to patients’ death upon delayed treatment. To provide accurate diagnosis and fast treatment of paracetamol poisoning, rapid analysis of paracetamol in patient tissues is necessary. In this study a rapid and simple high performance liquid chromatographic method was developed to analyse plasma/serum and urinary paracetamol using 100 μL of specimen. Paracetamol is chromatographically resolved, with an isocratic mobile phase followed by UV detection after protein precipitation. -Hydroxyethyltheophylline was used as the internal standard. The elution of paracetamol and the internal standard was achieved within 8 minutes. The calibration curve was linear over 0.25-200 mg/L. This method produced excellent accuracy and precision in all matrices tested. Intra and inter day variability was less than 5%. The limits of detection were 0.13 mg/L for plasma and 0.43 mg/L for urine, whereas the limits of quantification were 0.68 mg/L for plasma; and 2.25 mg/L for urine. No matrix effects were observed with endogenous substances. This method is applied to analyze paracetamol levels in serum of accidental or self poisioning patients. Keywords : HPLC, paracetamol analysis, paracetamol overdose. J.Natn.Sci.Foundation Sri Lanka 2010 38 (2):131-137 Doi: 10.4038/jnsfsr.v38i2.2039

In vitro propagation of Coscinium fenestratum (Gaertn.) Colebr. (Menispermaceae) - an endangered medicinal plant

Abstract: Coscinium fenestratum (Gaertn.) Colebr. is an important medicinal plant belonging to the family Menispermaceae. Multiple shoots were formed from epicotyl explants on Murashige and Skoog (MS) medium supplemented with 1.0 μM kinetin (Kin) and 0.25 μM 2,4-Dichlorophenoxy acetic acid (2,4-D). A maximum of five shoots were obtained from one explant in a 75-day culture period. The effect of subsequent subcultures on shoot formation was also studied. Repeated subculture favoured the increase in shoot length and the number of shoots per explant in the media containing Kin and 2,4-D. Higher concentrations of either cytokinin used: butyric acid (BA) or Kin causes stunting of multiple shoots with small and narrow leaves. After 100% in vitr o rooting was obtained in half-strength MS supplemented with 2.5 μM Indole-3-butyric acid (IBA), plantlets were transferred to ex vitro conditions. Following a 15-day in vitro rooting period and 12 days of ex vitro acclimatization, 66.7% of the plantlets were established in the compost beds for another two months to improve the leaf size and then transferred to the field with 100% survival rate. This protocol has the potential for use as a tool for mass scale production of planting material. Keywords: Conservation, Coscinium fenestratum , Menis- permaceae, micropropagation. Doi: 10.4038/jnsfsr.v38i4.2648 J.Natn.Sci.Foundation Sri Lanka 2010 38 (4): 219-223

A study of Tribulus terrestris extract on risk factors for urinary stone in normal subjects and urolithic patients

Abstract: This study was conducted to determine the effect of Tribulus terrestis extract on urinary risk factors in normal subjects and urolithic patients. Twenty five urolithic patients and 18 normal subjects were selected and administered once daily with 10 mL of T. terrestris extract for one week. Serum, urine collected between 10 pm and 6 am, and 24 h urine samples were analysed for urinary risk factors for stone formation on day 0 and day 8 after administration of the extract. In urolithic patients the mean serum calcium level increased significantly and the mean urinary calcium level decreased significantly after treatment for one week with T. terrestris extract. The mean uric acid level of the urolithic patients decreased significantly in serum and urine after treatment with T. terrestris extract. The mean citrate, oxalate, proteins and glycosaminoglycan levels decreased significantly in urine collected between 10 pm and 6 am, and 24 h urine samples of the urolithic patients after treatment with the extract. Urine volume and phosphate level in serum were not altered significantly in the urolithic patients. Hence T. terrestris extract may be useful in the treatment of urolithiasis.

Systematics of genus Garcinia L. (Clusiaceae) in Sri Lanka: new insights from vegetative morphology

Abstract: The genus Garcinia L. (Family: Clusiaceae) is represented by ten species in Sri Lanka including five endemic species. Systematics of the genus hitherto were primarily based on reproductive morphology. A recent study was carried out in order to evaluate the species limits of Sri Lankan Garcinia using anatomical characters. However, the field identification of Garcinia is challenging due to the presence of unisexual flowers, strict seasonality in flowering and fruiting, and failure to use anatomical characters. The aim of this study was to investigate the relationships among the species and to construct an identification key based on the vegetative morphological characters. Specimens of all representative taxa were sampled from different geographical locations. A total of 97 specimens were collected and similarity and cladistic analyses were performed based on 47 vegetative morphological characters. The results suggest that the sampled species fall into two major groups characterized by leaf morphological features. Major groups can be further divided into subgroups by bark colour and tertiary venation. The overall results demonstrate within species variations of G . hermonii and G . terpnophylla highlighting the presence of different varieties. The dichotomous key constructed using conspicuous vegetative characters will be a valuable tool for identification of Sri Lankan Garcinia species in the field. The relationships found in this study provide insights to the phylogeny of the species. The results are congruent with those of the recent anatomical study and revealed the importance of combined multidisciplinary data analysis to elucidate more robust species relationships. Keywords: Bootstrap, cladistic, Garcinia, phylogeny, strict consensus tree, vegetative morphology doi :10.4038/jnsfsr.v38i1.1723 J.Natn.Sci.Foundation Sri Lanka 2010 38 (1):29-44

Hepatotoxicity of Schiff bases derived from benzoin salicylaldehyde, aminophenol and 2,4 dinitrophenyl hydrazine

Abstract: Hepatotoxicity of three Schiff bases viz. PDH (N-(1- phenyl-2-hydroxy-2-phenyl ethylidine)-2 / ,4 / dinitrophenyl hydrazine),PHP(N-(1-phenyl-2-hydroxy-2-phenylethyli dine) 2 / hydroxy phenyl imine) and HHP (N-(2-hydroxy benzylidine)-2 / hydroxy phenyl imine) in both mice with and without Ehrlich Ascites Carcinoma (EAC) was studied. The parameters selected were serum level of the enzymes alanine transaminase, aspartic transaminase, alkaline phosphatase, glucose, blood urea and cholesterol. In mice with no carcinoma there was a modest increase in all the above parameters during the treatment period (10 consecutive days at the dose of 2 mg/kg). After treatment the enhanced values gradually decreased to normal levels. In EAC bearing mice, the toxic effects due to EAC cells in all cases were found to be nullified by treatment of the test compounds. No significant abnormalities in histology of the various organs of the mice were detected due to such treatments.

Studies on the Carotenoids and in vitro Antioxidant Capacity of Palmyrah Fruit Pulp from Mannar

Abstract: The pulp of palmyrah (Borassus flabel1ifer.L) fruits collected from Mannar i n the North-West of Sri Lanka was used for the study. The 4 types of palmyrah fruit collected in Mannar, represented >95% of all fruit types of palmyrah. Carotenoids of palmyrah fruit pulp were separated by open column chromatography. Identification and quantification of the carotenoids were carried out using a scanning spectrophotometer with the aid of a standard uv-visible spectral bank for carotenoids. Type I, 11-A and I11 fruit pulps showed spectra dominated by phytoene and neurosporene and were largely non-provitamin A. Type IIB fruit pulp showed spectra high in phytofluene and had a retinol equivalent of 9.8.100g1 fresh weight from p-carotene and p-zeacarotene. The pulp contained both hydrophilic and lipophilic antioxidants with total antioxidant varying from 2.4-21.8 trolox equiva1ent.g-I determined by the 2-2l The main stands of palmyrah occur in the Jaffna peninsula, Mannar and the Wanni. In Jaffna the stands showed only type I and type I1 fruits. The Wanni was inaccessible to the workers and they were also constrained to study PFP from Mannar. This is the first study on carotenoids from pulp that had been seperated from fruits classified according to morphological type.2 The only report on the antioxidant effect of PFP is an i n vivo study of a sample of unknown rigi in.^ The objectives of this study were to: azino-bis-benzothiozoline-6-sulphonic acid free radical cation (ABTS+'). The antioxidant levels measured as trolox (i) Quantify the separated carotenoids of equivalents of the separated carotenoids gave values palmyrah fruit pulp from fruit types I, generally consistent with the extent of conjugation of 11-A, 11-B and 1112 of Mannar (type IV2 double bonds. is found only in Kalpitiya) in order to determine their retinol equivalent.

Identification of fragrant gene, fgr, in traditional rice varieties of Sri Lanka

Abstract: A study was conducted to identify traditional rice varieties of Sri Lanka that possess the fragrant gene ( fgr ) using designed allele specific markers based on the gene sequence of mutated version of Betaine Aldehyde Dehydrogenase 2 (BAD2), which is called fragrant gene. Fifty six rice accessions including several Basmati, Suwandal, Samba and Heenati varieties, were chosen for the polymerase chain reaction (PCR) amplification with fgr would markers. Three fragments that would discriminate homozygous fragrant, homozygous non-fragrant and heterozygous individuals were amplified by multiplex PCR and the fragrance was evaluated phenotipically by potassium hydrooxide (KOH) treatment. All positive accessions that amplified the fgr allele expressed the fragrance with KOH treatment. Of the traditional varieties, one accession each from Suwandal and Samba and, two accessions from Heenati were identified as the fgr genotypes that possessed mutated BAD2. Information from the investigation could be applied in breeding studies on aromatic rice suitable for the Sri Lankan environment, using marker assisted selection with local germplasms. Keywords: Fragrant gene, marker assisted selection, Oryza sativa L., polymerase chain reaction. J.Natn.Sci.Foundation Sri Lanka 2010 38 (2):139-143 Doi: 10.4038/jnsfsr.v38i2.2040

New Outlook on the Pest Management of Tea

Abstract: An intensive ten year study on the pest ecology of tea has spotlighted some aspects which explain the unsatisTactory chemical control of many pests of tea, such as, tea tortrix, mites and shot-hole borer beetle. Evidence from past experimentation has revealed that in many instances the use of insecticides for pest control in tea has proved to be neither ecologically feasible nor economically worthwhile. b It 1s suggested that in future pest control in tea should be oriented towards bio-cultural techniques of regulating pest populations.

Activated coconut shell charcoal as a component of tissue culture media of Cocos nucifera L.

Abstract: In vitro culture media of Cocos nucifera L. (coconut) requires a guaranteed source of activated charcoal with consistent characteristics for reliable results. Activated coconut shell charcoal (ACSC) was tested as a component of the media since a continuous supply of a particular type of activated charcoal with the same origin and characteristics was guaranteed by the manufacturer. Immature zygotic embryos of coconut (variety Sri Lanka Tall) were cultured in basal medium supplemented with two different types of ACSC (A and B) (Haycarb PLC) and BDH charcoal (control).The optimum 2,4 dichlorophenoxyacetic acid (2,4-D) levels to be used with different activated charcoal types were also assessed by culturing of explants and HPLC. The more suitable ACSC type was further tested by culturing plumule explants of coconut. The study revealed that in the presence of suitable concentrations of 2,4-D, media with both ACSC types could produce calli at frequencies comparable to that of the control. Considering the production of calli and mixing qualities of activated charcoal with the medium, ACSC-B was selected as the better ACSC type for coconut callogenesis. In the presence of 175.0 µM 2,4-D, the selected ACSC-B induced callusing in 63 and 65 % of immature zygotic embryos and plumules while the control produced 63 and 70 % callusing in respective tissues.

Alkaloids from Xylopia parvifolia and Xylopia nigricans (Annonaceae)

Abstract: Shanmugam Puvanendran, Tharmaraja Manoranjan, Anura Wickramasinghe, D. Nedra Karunaratne, Vijaya Kumar, Siril Wijesundara, Gavin Carr, Raymond Andersen and Veranja Karunaratne 1 Department of Chemistry, Faculty of Science, University of Peradeniya, Peradeniya. 2 Royal Botanic Gardens, Peradeniya. 3 Departments of Chemistry & Earth and Ocean Sciences, Faculty of Science, University of British Columbia, Vancouver, B.C., Canada. J.Natn.Sci.Foundation Sri Lanka 2010 38 (1): 75-76

A preliminary study on quantification of biological nitrogen fixation in sugarcane grown in Sevanagala in Sri Lanka

Abstract: The extent of nitrogen(N) fixation in sugarcane grown in reddish brown earth soils in Sevanagala was determined using the difference in 15 N abundance in the top visible dewlap leaves of sugarcane (variety CO 775, SL 8306) compared to those of neighbouring weeds. Results indicate that biological N 2 fixation contributed to an average of 18% of the total N in sugarcane in the study site.

Growth variations of edaphic specialist species in a reciprocal pot experiment in Sri Lanka

Abstract: Edaphic factors may determine the habitat associations shown by some tropical trees. In Sinharaja, a tropical rainforest in Sri Lanka, about 79% of tree species show habitat preferences. The present study attempted to investigate the role of edaphic factors in determining habitat specialization, using a reciprocal pot experiment with four edaphic specialist species ( Agrostistachys hookeri , Semecarpus gardneri, Mesua nagassarium and Agrostistachys intramarginalis ). Both Agrostistachys species showed increased growth rates and total biomass when grown in their native soils compared to that of non-native soils, while M. nagassarium showed a better growth in non-native soils. Higher biomass allocation to roots was evident in all species when they were grown in sand- rich valley soil irrespective of their specialized soil type. No significant trend was observed in foliar nutrient concentrations when grown in native or non-native soils. The results suggest that edaphic factors play a vital role in the spatial distribution of Agrostistachys species. This is perhaps due to plants showing more acclimatory shifts when grown in their native soils compared to non-native soils. The results also suggest the importance of other factors such as plasticity, water-use efficiency and herbivory in the spatial distribution of plants.

Identification of Trichoderma asperellum from selected fruit plantations of Sri Lanka

Abstract: Three isolates of Trichoderma asperellum (TR1, TR2, and TP3) isolated from soil samples collected from rambutan ( Nephelium lappaceum ) and pineapple ( Ananas comosus ) plantations in Sri Lanka had similar characteristics with respect to growth at different temperature, pH and media. The three isolates are reported to be antagonistic to fungal pathogens of pineapple (i.e. Thielaviopsis paradoxa ) and rambutan (i.e. Colletotrichum gloeosporioides ). Analysis of genome DNA of the isolates showed that the isolated fungi were T. asperellum . This is the first report of the occurrence of T. asperellum in Sri Lanka. Keywords: Biocontrol agent, fungi, Trichoderma asperellum. J.Natn.Sci.Foundation Sri Lanka 2010 38 (2):125-129 Doi: Normal 0 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} 10.4038/jnsfsr.v38i2.2037

Optimization of parameters for effective removal of Cr(VI) species by burnt brick clay

Abstract: The extent of removal of Cr(VI) species from aqueous solution by brick particles is highly dependent on the firing temperature of brick clay used for removal of Cr(VI) species , since many physical and chemical changes occur during firing. The highest removal of Cr(VI) species by brick clay is obtained with clay fired at 200 oC. The amount of suspended matter is low with brick clay fired at temperatures ranging from 200 oC to 600 oC as seen with turbidity measurements. Optimization of parameters, such as duration of stirring (10 minutes) and settling time period (2 hours) , leads to 60% removal of Cr(VI) by brick particles fired at 200 oC in batch experiments, without pH control, despite the negative charge of the source of Cr(VI). Dynamic experiments conducted in packed columns also effectively remove Cr(VI). The extent of removal does not significantly depend on solution pH up to 11 and on common interferents.

A multivariate approach for developing a dichotomous key for identification and differentiation of Puntius (Osteichthyes: Cyprinidae) species in Sri Lanka

Abstract: Sri Lanka is a global biodiversity hot spot with a rich freshwater fish fauna. Out of a total of 82 freshwater fish species, the genus Puntius represents 16 species (19.5%). Ambiguities exist in taxonomic identification of the different Puntius species. Hence, in this study a dichotomous key was developed using morphometric and meristic characters to identify and differentiate the Puntius species. Altogether 421 specimens representing different Sri Lankan Puntius species were collected from 38 sites at four different altitude ranges from five major river basins in Sri Lanka. Fifteen meristic characters, four coded variables and twenty three morphometric characters were recorded for each specimen and characters were analysed using principal component analysis (PCA). Six principal components were extracted for meristic characters and coded variables that explained 81.5% of the cumulative variance in the dataset. Two meristic characters (number of transverse scales and number of post dorsal scales) and four coded variables (nature of the lateral line, position of mouth, number of barbels and nature of dorsal fin spines) were the variables that contributed most to the variance of the six principal components identified. The six characters were sufficient in isolation to develop a dichotomous key for all, except for two species. Two principal components extracted only for morphometric characters were also able to differentiate Puntius species but not to the same level as meristic characters and therefore, they contributed less to the dichotomous key developed here. Based on this approach, 15 Puntius species could be differentiated unambiguously. Keywords: Meristic , morphometric, principal component analysis, Puntius. doi :10.4038/jnsfsr.v38i1.1722 J.Natn.Sci.Foundation Sri Lanka 2010 38 (1):15-27

Response of tall buildings with symmetric setbacks under blast loading

Abstract: This study explores three-dimensional nonlineardynamic responses of typical tall buildings with and without setbacks under blast loading.These 20 storey reinforced concrete buildings have been designed for normal (dead, live and wind) loads. The influence of the setbacks on the lateral load response due to blasts in terms of peak deflections, accelerations, inter-storey drift and bending moments at critical locations (including hinge formation) were investigated. Structural response predictions were performed with a commercially available three-dimensional finite element analysis programme using non-linear direct integration time history analyses. Results obtained for buildings with different setbacks were compared and conclusions made. The comparisons revealed that buildings having setbacks that protect the tower part above the setback level from blast loading show considerably better response in terms of peak displacement and interstorey drift, when compared to buildings without setbacks. Rotational accelerations were found to depend on the periods of the rotational modes. Abrupt changes in moments and shears are experienced near the levels of the setbacks. Typical twenty storey tall buildings with shear walls and frames that are designed for only normal loads perform reasonably well, without catastrophic collapse, when subjected to a blast that is equivalent to 500 kg TNT at a standoff distance of 10 m. Keywords: Blast loading, dynamic analysis, hinge formation, setbacks, tall buildings. J.Natn.Sci.Foundation Sri Lanka 2010 38 (2):115-123 Doi: 10.4038/jnsfsr.v38i2.2043

Cyclic voltammetric study on the effect of the introduction of secondary ligands on the redox behaviour of the copper-saccharin complex

Abstract: The detailed redox behaviour of copper-saccharin (Cu-sac) complex was examined using the cyclic voltammetric technique. It was found that the adsorption process suppresses the Faradaic process of the Cu-sac complex. The effect of the introduction of secondary ligands such as 1,10 -phenanthroline (phen), pyridine (py) and bypyridine (bp) on the redox behaviour of the Cu-sac complex in aqueous solution was studied where these ligands contribute on the charge-transfer kinetics of the complex. The heterogeneous charge transfer rate constants are found to follow the order Cu(NO 3 ) 2 > Cu-sac-bp > Cu-sac > Cu-sac-phen > Cu-sac-py.

Claiming the sea area belonging to Sri Lanka according to the United Nations Convention on the Law of the Sea (UNCLOS)

Abstract: The United Nations Convention on the Law of the Sea (UNCLOS) provides a comprehensive legal and scientific framework for addressing various issues related to oceanic areas. One of the most important achievements of UNCLOS is the successful formulation of a set of criteria that determines the extent of sea area that a maritime country can claim under its jurisdiction. These criteria have been incorporated in the Article 76 of the convention and in the Annex II of the final Act. Article 76 of the convention provides the basis for a maritime country to demarcate its maritime boundaries. Paragraph 1 of the article 76 of UNCLOS states that the "continental shelf" of a maritime state comprises the seabed and sub-soil of the submarine areas that extend beyond its territorial sea throughout the natural prolongation of its land territory to the outer edge of the continental margin. The continental margin of a maritime state consists of the submerged prolongation of the seabed / sub-soil of the continental shelf, slope and rise. All the measurements related to demarcation of maritime boundaries have to be made from a baseline which is defined as the low water line of the maritime country that is normally used for surveying purposes. A maritime state can demarcate its outer edge of the continental margin using one of the formulae provided in paragraph 4(a) of the Article 76. The first formula is known as the sediment formula or Irish formula and it allows a maritime state to claim the adjacent sea area up to a boundary where the thickness of oceanic sediments is 1% of the distance measured from the foot of the slope. This boundary should not exceed 350 nautical miles from the baseline mentioned above. The second formula which is known as the Hedberg formula, named after a renowned American geologist Hollis Hedberg, states that a maritime country can claim the adjacent sea area up to a distance not more than 60 nautical miles from the foot of the continental slope. This boundary should not exceed 100 nautical miles from the 2500 m isobath. In both these formulae, the foot of the continental slope means the point at which the bathymetry shows the maximum change in slope. In response to submissions made by the Government of Sri Lanka with regard to inequity that would arise to Sri Lanka as a result of application of Article 76, a special method of establishing maritime boundaries for countries south of the Bay of Bengal has been formulated during the Third United Nations Conference of the Law of the Sea held in 1982. This special method has been incorporated in the Annex II of the final Act as a statement of understanding and is applicable for maritime states, which satisfy the following criteria; 1. Average distance at which the 200 m isobath occurs is not more than 20 nautical miles from the baseline. 2. Mathematical average of thickness of sedimentary rocks lying along the boundary established at the maximum permissible distance according to Article 76 would not be less than 3.5 km. It is generally understood that Sri Lanka can satisfy the above criteria and use Annex-II to delimit its outer edge of continental margin. In claiming the outer edge of the continental margin of Sri Lanka beyond the exclusive economic zone using Annex II, it is necessary to determine the boundary at which thickness of sediments lying in the Indian Ocean region around Sri Lanka is one kilometer. Technical guidelines issued by the convention for this purpose recommend that multi-channel seismology is the most suitable method for this purpose. The government of Sri Lanka set up a special project under the purview of the Ministry of Foreign Affairs and the Ministry of Fisheries and Aquatic Resources to carry out scientific surveys related to the demarcation of maritime boundaries of Sri Lanka. With the help of a group of dedicated geologists, geophysicists and hydrographers, some of whom were working on a voluntary basis; initial planning of the seismic survey was carried out. This involved determining the approximate boundary of the outer edge of the continental margins using results of single channel seismic work carried out over the region by some geophysical institutes in the USA, Germany and Russia, the Deep Sea Drilling Project (DSDP) and results of interpretation of satellite gravity anomalies carried out by local geophysicists. According to the results of these studies Sri Lanka can claim an oceanic area almost equal to twenty-five times of its land area. This area covers a large extent of the southern part of the Bay of Bengal with a thick sediment cover having a high potential of hydrocarbon accumulation. In the early part of 2007, the DEOCOM project (Delimitation of the Outer Edge of the Continental Margin of Sri lanka) commissioned a UK based geophysical company, Gems Geophysical Ltd. to conduct a geophysical survey following the cruise tracks based on the results of the above mentioned studies. In this survey, reflection seismic and gravity data were acquired over a distance of approximately 7000 km using the research vessel MV Geo Searcher over a period of about seventy days. Using the results of this survey, Sri Lanka's claim was prepared by a group of local scientists and legal experts with the assistance of several foreign experts who have been involved in the preparation of similar claims for their own countries. The deadline imposed by the UN Commission for maritime countries to make their submissions was 13th May 2009. Sri Lanka was successful in making its submission on 8th May 2009. However, over forty two maritime countries had submitted their claims before us and the date on which our claim will be considered by the UN Commission on the Limits of the Continental Shelf (CLCS) will be delayed as a result of this. Considering the number of countries making their submissions prior to us, it is unlikely that our claim will be taken up for hearing before 2025 and therefore we should have a group of competent Sri Lankan scientists and legal experts ready by that time to defend our claim. Undoubtedly, the most competent people to defend Sri Lanka's claim at the CLCS are those who were involved in the preparation of the claim. Most of the scientists and legal experts who took part in the preparation of the claim are very senior people and it is unlikely that they will be in active service in another 15 years time. Therefore, there should be a comprehensive programme to transfer this knowledge to a younger generation who can successfully defend the claim in 2025. One way of achieving this is by making funding available for studies related to the geology and geophysics of the Indian Ocean around Sri Lanka and also focusing on the legal issues related to delimitation of continental margins. These studies can be carried out at postgraduate level at Sri Lankan Universities with those who were involved in preparation of the original claim as their research supervisors. Vast amounts of gravity and seismic data collected around Sri Lanka during the survey carried out by the DEOCOM can be gainfully utilized for this purpose. Academic studies at postgraduate level using this data will certainly ensure smooth transfer of knowledge to the younger generation, thus establishing a vital link between the experts of today and those of tomorrow, paving the way for the successful defense of our claim for the outer edge of the continental margins of Sri Lanka in 2025. doi :10.4038/jnsfsr.v38i1.1720 Normal 0 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} J.Natn.Sci.Foundation Sri Lanka 2010 38 (1):1-2

A DNA betasatellite - begomovirus complex associated with leaf curl disease of Cardiospermum microcarpum (Kunth)

Abstract: Keywords: Begomovirus, Cardiospermum microcarpum (Kunth), Cotton leaf curl Multan betasatellite, DNA betasatellite. J.Natn.Sci.Foundation Sri Lanka 2010 38 (2): 151-153 Doi: Normal 0 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} 10.4038/jnsfsr.v38i2.2038

Phylogenetic positions of some species of the genus Macrobrachium Bate, 1868 (Crustacea, Decapoda, Palaemonidae) in Sri Lanka

Abstract: Macrobrachium species, are an economically important freshwater prawn group in Sri Lanka. These species are recognized by their local names and many synonyms can be found for one species. Identification of taxonomic positions and species boundaries within the genus is important to obtain reliable information for application in aquaculture and biodiversity conservation programmes. Approximately 471bp partial sequences from mitochondrial 16S rRNA using seven Macrobrachium species were collected during the present study. Six of them were collected from the southern part of Sri Lanka and their phylogenetic positions among the relevant species that have been recorded within the region were determined. The analysis resulted in five clades, of which three showed monophyletic lineages ( M. australe group, M. latimanus group, and M. latidactylus group). M. malcolmsonii is in a sister clade to M. rosenbergii while M. scabriculum joined with M. idae . The estimated intraspecific nucleotide divergence level varied from 0 " 6.07% while it varied from 5.21 - 10.84% at the interspecific level. The phylogenetic positions of the samples recorded within the region are discussed.

In vitro regeneration of shoots from Garcinia quaesita leaf explants

Abstract: Garcinia quaesita is an economically valuable plant, which has a huge demand in the local as well as the export market. Lack of good quality products throughout the year coupled with the unavailability of quality planting material is a major drawback in the cultivation of G. quaesita . Thus, in the present study large scale multiplication of G. quaesita using tissue culture techniques was investigated. Leaves and nodal segments were obtained from plants maintained under green house conditions. The effect of benzylaminopurine (BAP) and naphthalene acetic acid (NAA) on shoot initiation from leaf explants and the effect of BAP on proliferation of nodal segments were investigated. The effect of indole-3-butyric acid (IBA) and NAA on rooting of micropropagated shoots was also studied. Shoots were successfully initiated by culturing in vitro grown leaves and immature leaves from greenhouse grown plants on Murashige and Skoog (MS) medium supplemented with 5.0 or 10.0 mg L-1 BAP in complete darkness. Within 24 weeks, 9−12 shoots could be produced from a single leaf explant (10 mm x10 mm). Further growth of G. quaesita nodal explants could be achieved by culturing on MS medium supplemented with 20.0 mg L-1 BAP. Rooting could not be achieved on MS medium supplemented either with IBA (1.0, 5.0, 10.0 mg L-1) or NAA (1.0, 5.0, 10.0 mg L-1). Keywords: Garcinia quaesita , micropropagation, shoot induction. J.Natn.Sci.Foundation Sri Lanka 2010 38 (3): 157-162 Doi: 10.4038/jnsfsr.v38i3.2304

Morphological aspects of coconut anther culture derived structures

Abstract: Anthers excised from male flowers of an adult coconut palm of Sri Lanka Tall cultivar were used to produce plants via androgenesis. Morphological aspects of the anther-derived structures and their plant regeneration pathways were studied. Under the culture conditions employed, both calli and embryo-mediated plant regeneration were observed. Two types of embryos with different germination patterns were identified-one with a germination point and the other type with a blunt haustorium without a prominent germination point which converted into germinated embryos. Three types of calli (embryogenic compact calli, embryogenic friable calli and non-embryogenic fast-growing calli) were also produced and the most commonly identified type was embryogenic compact calli that give rise to somatic embryos. Secondary somatic embryos were produced in both direct embryo and callus mediated embryogenesis. Normal plants with a single shoot were observed in low frequencies while weak plantlets with multiple shoot were observed in abundance. Under similar culture conditions, some plantlets showed vigorous growth whereas the majority had a slow growth rate. Keywords: Androgenesis, anther culture, callus, coconut ( Cocos nucifera L.), embryo, morphology doi :10.4038/jnsfsr.v38i1.1727 J.Natn.Sci.Foundation Sri Lanka 2010 38 (1): 69-74

Cytoadherence and its association with clinical disease in Plasmodium falciparum infections in Sri Lanka

Abstract: Cytoadherence properties of two categories of Plasmodium falciparum isolates from Sri Lanka were assessed using CHO-CD36 and CHO-ICAM-1 stable transfected cell lines, and the association with the clinical disease in patients, from whom the parasites were obtained was also analyzed. In the 40 uncomplicated malaria isolates (UM) studied, infected erythrocyte (IE) adherence to CHO-CD36 cells (25.8±2.1) was comparable to that of the 12 severe malaria (SM) isolates (35.0±6.4). IE adherence to CHO-ICAM-1 cells of the SM isolates (14.9±2.3) were significantly higher (p=0.006) compared to that of UM isolates (5.7±0.7). The percentage of isolates forming rosettes in the two clinical categories, UM and SM, were 69% and 42% respectively. However, the mean rosetting values were not statistically different (10.5±2.9 and 2.9±1.7). Expression of surface antigens was studied using assays for surface immunofluorescence and antibody mediated agglutination. All 40 UM isolates were positive for expression of surface antigens. In the UM group, the intensity of clinical symptoms, as expressed by a clinical score, was significantly and positively correlated to IE adherence to CHO-ICAM-1 (r=0.54; p=0.003) but not to CHO-CD36 cells or rosetting. The intensity of clinical symptoms was also significantly correlated with peripheral blood parasitaemia of these patients (r=0.39; p=0.037). However, the association between adherence to ICAM-1 and intensity of clinical symptoms was independent of the peripheral blood parasitaemia of the patients (multiple regression analysis controlling for parasitaemia; p=0.016). These results show that IE adherence to ICAM-1 may have implications for the intensity of clinical symptoms and the severity of infection in falciparum malaria. Keywords : Cytoadherence, pathogenesis, Plasmodium falci − parum , Sri Lanka, surface antigens. Doi: 10.4038/jnsfsr.v38i4.2650 J.Natn.Sci.Foundation Sri Lanka 2010 38 (4):233-240

Assessment of tsunami threat to Sri Lanka from potential mega-thrust earthquakes in the Arakan subduction zone

Abstract: This paper describes a numerical study carried out to assess the threat posed to Sri Lanka by potential tsunamigenic earthquakes in the Arakan subduction zone in the northeastern Bay of Bengal The fault plane model adopted in the present simulations corresponds to a moment magnitude of Mw = 88, which may be considered as a worst-case scenario A hydrodynamic model based on linear shallow-water equations was employed to simulate tsunami propagation from the source to the shoreline around Sri Lanka The model results extracted at an average water depth of about 5 m off the coastline were processed to obtain the spatial distribution of the maximum value of the ‘tsunami amplitude’ (ie, the height of the crest of the tsunami waves above mean sea level) as well as the arrival time contours for the leading wave The numerical simulations suggest that the coastal zone of the Northern Province is at most risk from a tsunami generated in the Arakan fault plane with maximum tsunami amplitudes of the order of 10 m, whilst the maximum amplitudes along the coastal belt of the Eastern and Southern Provinces could reach up to about 56 m and 26 m, respectively On the other hand, the coastline in the Western Province in the shadow zone of direct tsunami impact will only receive waves of small amplitude up to 06 m The numerical results also indicate that the tsunami waves will first hit the east coast about 160 minutes after the earthquake, followed by the coastal belts of the Northern and Southern Provinces The information presented in this paper relating to likely tsunami amplitudes and arrival times around the coastline of Sri Lanka would help authorities responsible for evacuation to make better judgement as to the level of threat in different areas along the coastline, and to act accordingly, if a large earthquake as to occur in the Arakan subduction zone in future Keywords: Arakan subduction zone, hazard assessment, numerical modelling, shallow-water equations, tsunami amplitude JNatnSciFoundation Sri Lanka 2010 38 (2): 101-108 Doi: 104038/jnsfsrv38i22042