PURSE 2013

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School-based teacher professional development programms in Sri Lanka
(The University of Peradeniya, 2013-07) Bandara, B. M. S.
Teacher professional development is a key factor for improving the quality of student outcomes. Under such a situation, teachers have to update and intensify their knowledge, skills, attitudes and practices according to student demands. In this context, School-based teacher professional development is a very important concept, because it allows teachers to plan, organise and implement their own professional development programs, considering their particular needs, as well as those of students and schools. However, this concept has not been extensively developed in the Sri Lankan education context. A new concept for Sri Lanka, school based management was introduced in the late 1990s to the Sri Lankan education system. Through school-based management the power and authority were decentralised from the central government to particular individual schools. Therefore, since the last decade principals and staff have had the opportunity to plan, organize and implement their own teacher professional development. As such, focusing on the Sri Lankan secondary school context, this study examines the possibilities, effectiveness, strategies, issues and challenges involved in implementing these programs. Simultaneously, the situation of non-school-based teacher development programs are also examined because these are currently prominent and this study assumed that both programs need to be integrated in order to provide balanced teacher professional development. The research design was based on the qualitative research approach and the case-study strategy was been employed. Ten secondary schools were selected from three educational districts in two provinces in Sri Lanka. The data were collected by conducting interviews, non-participative observation and sample-based documentary search. The data was coded, presented and discussed in four themes. Further, the data were analysed using the Activity Theory framework in order to investigate the complex inter-relationships of the individual components of the school-based teacher professional development program’s activity system. According to the findings, eleven recommendations were proposed and relevant guidelines were suggested for future researches.
An analysis of academic performance of undergraduates
(The University of Peradeniya, 2013-07-04) Weerahewa, Jeevika; Bulathwela, Sahan; Silva, Pradeep; Perera, Kalyani
The objective of this study is to assess the extent to which academic history vis-à-vis other factors influence the academic performance of the undergraduate students in the Faculty of Agriculture, University of Peradeniya in Sri Lanka. A series of educational production functions were estimated treating Grade Point Average of students at semester level and cumulative Grade Point Average as the measures of academic performance. Academic history, engagements in student associations and other extra-curricular activities, learning environment, associations with the teaching staff, resources and support services provided by the university, social interactions, psychological factors, family background, funding and student inherent characteristics/personal background were hypothesized as the factors affecting academic performance. A structured questionnaire was distributed among 196 students in the final year of Agricultural Technology and Management degree program offered by the Faculty of Agriculture in 2011 to gather the needed data and 121 students responded to the survey. Results of the econometric models specified at semester levels reveal that during the first semester, English language proficiency, efforts made by the student and family background have positive and statistically significant effects on academic performance of undergraduates while the performance during semesters 2-7 is largely driven by the performance of the previous semester. A significant gender disparity in academic performance of undergraduates exists. In general, female students perform better than the male students and psychological factors explain a considerable proportion of the variability of academic performance. The results further reveal that the overall academic performance is influenced by the language proficiency and the academic efforts made by the students. Female students and those who came from privileged districts perform much better than their respective counterparts. Academic performance at school does not have a significant effect even when the other factors affecting undergraduate performance are controlled for. The study concludes that the English language proficiency, family background and academic efforts made by the students are the three key elements that determine the academic performance at every level. Contrary to the expectation, the performance at the Advanced Level examination, as measured by the Z score, does not seem to influence undergraduate academic performance in a statistically significant manner. The above findings imply a need to upgrade the facilities to improve English language proficiency and to create an enabling learning environment primarily through strengthening of social interactions and enhancing psychological spirits of undergraduates in order to obtain the best return for the investment made in higher education in Sri Lanka.
Simultaneous analysis of negative parity 70-plet baryon properties in large Nc QCD
(The University of Peradeniya, 2013-07-04) Premaratne, Shavindra; Jayalath, C. P.
Non-strange members of the 70-plet baryons are analyzed within Large Nc QCD. The Large Nc approach is used as an effective theory to simultaneously fit the masses and decays with corrections up to O(1/Nc). Values of the mixing angles for the S=1/2 and S=3/2 nucleon mass eigenstates are obtained. The observed effective operator hierarchy is consistent with the previous studies conducted in this sector and improved results are obtained.
Building chemistry concepts by eighth graders through problem based learning
(The University of Peradeniya, 2013-07-04) Wathurakumbura, S. K.; Karunaratne, S.
Many students think chemistry has no relationship with their lives and consider it difficult to build up chemistry concepts. Therefore, educators have been thinking of innovative teaching learning strategies for learning chemistry concepts in an interesting manner. Problem-Based Learning (PBL) is an effective instructional strategy to address the above problem. Therefore, this study was aimed to investigate the effectiveness of learning chemistry concepts in 8th grade curriculum to the unit on, “Matter, atom, molecule, element and compound” through PBL. The present study was conducted in two schools, one in Kandy and the other in the Kurunegala district considering the convenience of the researcher. Two parallel science classes were selected from each school. Fifteen lessons were developed as ill-structured problems for PBL classes and discussed in detail with the two science teachers about the way of presenting these lessons to the students. One group of students was taught using PBL and the other group in the traditional way by the same teacher in 15, forty-minute periods in each school. The teachers completed the unit in three weeks. Data were collected through participant observation, videotaping lessons, interviews, a diagnostic test and an achievement test. Data collected from multiple sources were analyzed by triangulating data. Two sample t-tests were also used for quantitative analyses. The study revealed that there was active participation of students in PBL classes in solving problems together in groups. This shared learning experience enabled them to develop an interest in chemistry learning and to develop communication skills, presentation skills, critical thinking and reasoning ability which promoted learning chemistry concepts. They were able to make a shift from note-taking to note-making for better understanding. The two teachers were able to see unseen behaviour of students and to hear unheard voices of students leading them to rethink their previous instructional methodologies. They had enough room to identify student difficulties and wanted to extend this experience in developing future lessons. In non-PBL classes students did not play an active role and totally depended on the teacher’steaching. Two sample t-tests also revealed that there was a significant difference in achievement scores of the PBL groups compared to non-PBL groups. Problem–based learning approach enhanced students understanding of learning chemistry concepts and is more effective in learning chemistry concepts at junior secondary level in Sri Lanka.
Evaluating a data level parallelism approach in drug discovery research
(The University of Peradeniya, 2013-07-04) Senanayake, U.; Sivanathan, A.; Ragel, R.
Bioinformatics has progressed into a widely explored research area due to the significant innovation it places on conventional methods. Structural Bioinformatics is a main branch where molecular interactions are studied at the structural level. This paper addresses a problem in molecular docking that has taken the experimental level molecular interaction to in-silico interactions. The need for this is closely associated with the exponential growth in the identified number of proteins and ligands. Protein ligand docking can be considered as a lock and key problem where we have to find out the correct orientation of the ligand that can bind to the protein receptor. It is considered as an integral segment in drug designing which is known as lead identification. Repeated application of docking operation known as Virtual Screening (VS) is used for this purpose and Autodock Vina can be considered as standard software that is utilized by professionals. This paper explores an approach that utilizes data level parallelism and evaluates its scalability and performance on a clustered environment. The rationale behind this evaluation is to understand the feasibility of using this mechanism in large scale drug discovery research. As such, it should be scalable on top of a cluster to effectively materialize the full potential of the cluster. The parallelizable component and serial component of Autodock Vina is experimentally derived using Amdahl’s law and the throughput improvement is further evaluated according to the Gustafson’s principle. By deriving the parallelizable fraction, one can understand the lower bound of the throughput enhancement that can be introduced by parallelizing Autodock Vina. It is also implied that the molecular docking problem cannot be modelled using Gustafson’s principle. This is an important segment in academic research where it provides a solid theoretical interface between the implementation and theoretically derived implications. A complete scalability evaluation was carried out by observing the aforementioned approach in a clustered environment and measuring the individual and collective elapsed times with respect to different conditions. The results were then compared with the implications derived by Amdahl’s law and Gustafson’s principle to understand the applicability of the relevant models. Hence it is rational to conclude that the DLP approach in drug discovery research can be used in large scale virtual screening processes carried out around the world therein making an important contribution to drug discovery research.
Moleculardetection of Begamovirus Associated With Leaf Curl Complex of Chilli in Sri Lanka
(The university of Peradeniya, 2013-07-04) Sachika, G. G. A.; Dharmadasa, K. N. P.; De Costa, D. M.
Chilli Leaf Curl Complex (CLCC) is a serious biotic threat to chilli cultivation in Sri Lanka and causes substantial yield losses. CLCC is a result of chilli leaf curl virus (CLCV) infection and infestations due to thrips and mites. Plants infected with CLCC show a wide range of virus-related symptoms including leaf curl, leaf crumple, foliar mosaic, mottle, yellow discoloration of leaves, vein clearing and stunted growth of the plant. CLCV is a whitefly-transmitted virus belonging to the begomovirus group. In addition to CLCV, CLCC is associated with several other viruses belonging to different virus groups. However, due to the complex nature of CLCC symptoms and the complexity of etiology, identification of CLCV infections based on symptoms is not practically possible and conclusions are unreliable. Hence, molecular detection is essential and the Polymerase Chain Reaction (PCR) using virus specific primers is a possible option for effective, reliable and rapid diagnosis. The present study was conducted to detect begamovirus in CLCC-infected chilli plants by the PCR technique. Chilli plants showing typical CLCC symptoms were collected and subjected to PCR using begamovirus specific primers (i.e. Bega CPF/Bega CPR) with an initial denaturation at cellsius 94 for 2 min followed by 34 cycles at cellsius 94 for 1 min., cellsius 50 for 45 sec and cellsius 72 for 90 sec and a final extension at cellsius 72 for 10 min.. Size of the expected PCR product was 771 bp. CR products having the estimated size were subjected to direct DNA sequencing for confirmation. The sequence of the PCR products amplified by Bega CPR/ Bega CPF shared 82% nucleotide sequence identity with Chilli leaf curl Salem virus-India (Accession no. HM007119.1) and Chilli leaf curl virus-Bhavanisagar (Accession no. HM992939.1). The sequence of the PCR products also shared more than 90% nucleotide identity with tomato leaf curl Sri Lanka virus (Accession no. AF274349.1) confirming the reliability of PCR products obtained from the chilli plants infected with CLCC. Therefore, the present study confirmed the use of Bega CPR/ Bega CPF primers for successful detection of begamovirus infections in CLCC-infected plant samples when amplified under above PCR conditions.
Formation of Chitosan-Alginate Nanoparticles and Encapsulation of Curcumin
(The University of Peradeniya, 2013-07-04) Wimalasinghe, K. K. D. G. R. M.; Karunaratne, D. N.
Curcumin is a well known anticancer drug and colouring agent which is a poly phenolic compound. It can be extracted from the Curcuma longa rhizome via a simple laboratory method. Since it is water insoluble, handling of Curcumin is extremely difficult in biological systems. The main aim of producing nano drug delivery systems is for targeting delivery and slow release. Natural polymers are widely used for this purpose because they are biocompatible, and ecologically safe. Chitosan and Alginate, are highly hydrophilic polysaccharides. Formation of drug loaded gel beads with Chitosan or Alginate only, has been reported. However the sizes of these gel beads which are in the micrometer range are not very effective for sustained and gradual release of the drug. The size of the gel beads is important o obtain a successful drug delivery and desired solubility. Therefore, Chitosan-Alginate nanoparticles have been used as the mediator in drug delivery systems and other applications as they are water soluble and this blend of polysaccharides gives the drug loaded gel beads in nanometer scale. Particulate dispersion of solid in size 10-100 nm is defined as nanoparticles. Nanoparticles were obtained from the two step Rajaonarivony method with modifications. was used to obtain Calcium Alginate smooth ionic pre gel. Since Alginate and Chitosan are oppositely charged polymers, cross linking enhances the gel strength and also the sustained release of Curcumin from nanoparticles via a diffusion control mechanism or a swelling control mechanism. Therefore nanoparticles were obtained from a spontaneous nanoparticles formulation method. The Polymers were blended with different amounts of Curcumin to examine whether the invitro release is affected by the amount of drug initially loaded. All the release studies were done in pH 7.4 Phosphate Saline Buffer to provide physiological conditions. The release of the drug was analysed spectrophotometrically. The structural and morphological characterizations of nanoparticles were done using IR spectroscopy and Polarized Light Microscopy. Since Curcumin is highly hydrophobic Chitosan-Alginate nanoparticles formulation is the best method to prepare water soluble nanoparticles making Curcumin a drug with successfully enhanced slow release.
Controlling anthracnose of banana and papaya through gras (generally regarded as safe) compounds
(The university of Peradeniya, 2013-07-04) Gunawardhena, R. D. U. N.; Alahakoon, P. W.; De Costa, D. M.; Jayawardhana, N. H.
Colletotrichum musae and Colletotrichum gloeosporioides are the causative fungi of anthracnose of banana and papaya, respectively. Use of non-fungicidal approaches for the control of postharvest pathogens have become an emerging trend due to environmental and health hazards caused by application of fungicides. Experiments were conducted at the Fruit Crops Research and Development Centre, Horana to evaluate several non-fungicidal measures for the control of banana and papaya anthracnose. In the present study, efficiency of six GRAS (Generally Regarded As Safe) compounds were evaluated for the control of C. musase and C. gloeosporioides in comparison to a recommended fungicide (i.e. Chlorothaolonil 500SC). Sodium propionate at a concentration of 30000 ppm, Potassium sorbate at 20000 ppm, Sodium bicarbonate at 40000 ppm, Sodium metabisulphite at 1500 ppm, Cinnamaldehyde at 5 ppm and Clove Oil at 4 ppm, achieved complete growth inhibition of C. gloeosporioides in papaya. This was similar to the control achieved by the recommended fungicide, Chlorothalonil. Minimum effective concentrations of GRAS compounds which were able to cause 100% growth inhibition of C .gloeosporioides were applied for isolates of C.musae from banana (variety Kolikuttu). All the selected concentrations of GRAS compounds had the ability to cause 100% growth inhibition of C.musae isolated from the banana variety Kolikuttu. Hence C.gloeosporioides and C.musae from banana variety kolikuttu can be controlled by the same treatments under in vitro conditions. Under in vivo conditions, symptom development could be completely controlled by sodium metabisulphite (1500 ppm), sodium propionate (30000 ppm) and Chlorothalonil 500SC (2 ml/l) on papaya or banana fruits inoculated with the respective species of Colletotrichum. On the other hand, the minimum effective concentrations of the other GRAS compounds did not control the fungi completely in inoculated fruits in vivo. Based on the results of the present study it can be concluded that the tested GRAS compounds have the potential to be developed as non-pesticidal methods of anthracnose control in banana and papaya.
Thyroid dysfunction among subfertile women A retrospective study
(The University of Peradeniya, 2013-07-04) Nandakumara, S.; Nanayakkara, D.; Herath, S. S.; Sivakanesan, R.
Subfertility is defined as the inability to conceive following twelve or more months of unprotected intercourse. Among numerous factors causing subfertility in women, thyroid dysfunction has also been noted as a major contributor. There were only a few studies carried out in Sri Lanka about subfertility in women and those studies date back to the mid 1980s. The purpose of this study was to find the overall incidence of thyroid dysfunction among subfertile women who presented themselves to the subfertility clinic. The subjects included in the study were subfertile women referred to the Nuclear Medicine Unit for hormone assay. Based on day 21-25 progesterone values they were classified into four groups; anovulatory (Progesterone levels < 2ng/mL; 15 subjects), weak ovulation (2-15ng/mL; 55 subjects), strong ovulation (15-30ng/mL; 16 subjects) and ovulation induced (> 30.0ng/mL; 33 subjects). In the residual serum samples of those selected patients, TSH was estimated. Women with a history of thyroid dysfunction, clinical symptoms and under treatment were excluded from the study. One hundred and nineteen patients whose mean age was 31 years, were included in the study. The percentages of subjects below 35 years and above 35 years of age were 74% and 25% respectively. It was observed that a majority of subfertile women were euthyroid (TSH, 0.25-4μIU/mL) and 20% (24/119; TSH <0.25μIU/mL) were hypothyroid while only one was a hyperthyroid (TSH > 5μIU/mL) patient. Among anovulatory subjects the prevalence of hypothyroidism was 19%, in which the percentage of hypothyroidism among women older than 35 years of age was 17% and 22% among women below 35 years of age. Among women who had weak ovulation, 23% had hypo functioning thyroid and the extent of hypothyroidism was 29% in subjects older than 35 years of age. The percentage of hypothyroid patients in strong ovulation and ovulation induction groups were 19% and 21% respectively. Although age-related subfertility is noted in clinical settings, age had no effect on hypothyroidism related subfertility. According to results we conclude that about 20% of subfertile women are affected with hypothyroidism and it could be one of the reasons for their inability to conceive. Hypothyroidism is a treatable disease. Therefore, a thyroid function assessment has to be performed as a baseline test for subfertile women in the early stages of diagnosis.
Factors influencing the parent's choice of meal for their children, studying in the primary section of schools in the Galle sub-educational region
(The University of Peradeniya, 2013-07-04) Wijerathne, T.; Rajapakse, N.
Primary school children are at the onset of their school education. Their physical and intellectual performance during schooling depends on their nutritional status, which is influenced by the food intake. Parents decide on the food for children. Therefore parents choice of meal for their children (PCMC) is a critical factor in a child’s education. The aim of the study was to investigate factors that affect the PCMC in the Galle sub-educational region. The meals evaluated were those given during five days of schooling. A total of 411 questionnaires were filled using parents responses of 411 randomly selected students, from selected schools in the Galle sub educational region. Parents responses were analyzed using IBM SPSS V16. Parents giving priority to “Food being made at home” tended to decrease when the level of education of parents increased from GCE O/L to higher educational levels. Parents whose level of education increased from GCE ordinary level to higher education levels, often chose food made at home containing higher amounts of animal proteins, cereals and vegetables for their children. Mothers gave their children three times more food made at home compared to fathers. Fathers tended to give children six times more food purchased from shops compared to that given by mothers which was further confirmed by the fact that, fathers gave a high priority to the ease of preparation of food. Grandparents cooking at home decreased the mean number of days that children were given animal protein for lunch by 50%. Seventy seven percent of the parents considered the information from school when deciding the meal for their child. Information from either “mass media” or school has not made any significant (P>0.15) influence towards PCMC. These results suggest that four factors, namely the level of education of parents, the decision maker of food for the child, the person doing the cooking at home and the level of income of parents, have an influence on PCMC (P<0.15%). Higher levels of education of parents influenced parents to make better decisions on the childs meals. Mothers gave more food made at home compared to fathers. Grandparents influenced the PCMC by minimizing the quantity of animal protein given to the child. Measures to influence the PCMC by altering the factors that affect the PCMC can make a positive impact on a child’s level of nutrition.
Formulation, characterization and stability evaluation of a vergin coconut oil based emulsion
(The University of Peradeniya, 2013-07-04) Sanjeewani, N. A.; Sakeena, M. H. F.
An emulsion is defined as a heterogeneous system, consisting of at least two immiscible liquids or phases, one of which is dispersed as droplets in the other liquid. Virgin coconut oil (VCO) is gaining wide popularity in the scientific field and among the public, due to its various health benefits and special characteristics. The main objectives of this study were to formulate an emulsion containing VCO as the oil phase and Tween 20® as the surfactant and to optimize the emulsion with appropriate ratio of oil: water: surfactant. The effects of high shear on the optimized formulae and their characterizations were also studied in this project. VCO and Tween 20® were left for 20 minutes under magnetic stirring at 600 rpm at celsius 25 . To the resultant mixture water was added drop by drop in the method 1. In the method 2, high shear homogenization was applied for 5 minutes at 10000 rpm at celsius 25 to the formulations resulting from method 1. Based on the visual observations of stability studies, proper ratios of oil, water and surfactant were selected. A centrifugation test was also done to determine the stability of the formulations. The optimized formulae were further studied for its characterization such as droplet size measurement, pH value, creaming index, viscosity measurements and microscopic studies. According to the results the most stable formulation from both methods consisted of oil 32% (w/w), surfactant 32% (w/w) and water 36% (w/w). Particle size of the best formulae from method 1 and 2 were 653.8 nm and 484 nm respectively. Method 1 produced a micro-emulsion and method 2 produced a nano-emulsion which is below 500 nm. Creaming indexes were zero. Method 1 and method 2 produced different pH values and viscosities for the same formulation. Those pH values were suitable for topical application and zero value of creaming index was a good indicator of a stable emulsion. Microscopic studies indicated that the resulting best formulae were oil-in-water type (o/w) emulsion. In conclusion VCO is suitable for preparation of nano-emulsion and it gives an o/w emulsion. The best formulae consisted of oil 32% (w/w), surfactant 32% (w/w) and water 36% (w/w). High shear homogenization leads to substantial reduction of the particle size and increases the stability of the formulation compared to the conventional emulsion preparation method.
Record of five new endemic small mammal hosts for four species of ticks and fleas from Sri Lanka
(The University of Peradeniya, 2013-07-04) Saranga, Y.; Meegaskumbura, Suyama
Ticks and fleas are medically important arthropods, which act as vectors for several zoonotic diseases carried by mammals. Thirty three species of ticks and 20 species of fleas are reported from mammals, birds and reptiles in Sri Lanka. However, records of these ectoparasites on small mammals are scanty. Here, we report ticks and fleas infesting muroid rodents (rats, mice and gerbils) and shrews collected from several sites in Sri Lanka. Ectoparasites were collected during an extensive field survey of small mammals conducted from 2003-2005. Mammals were captured using Sherman and pit fall traps. Ectoparasites were collected using a pair of forceps and by combing. All the species of shrews, rats, mice and gerbils in Sri Lanka except, Suncus zeylanicus, Rattus montanus, Madromys blanfordi, Bandicota bengalensis and B. indica were included in the study. Of the 149 individuals of small mammals collected, 48 were infested with ticks (66.6%), fleas (20.8%) or both (12.5%). Larval and nymphal stages of four tick species including one unidentified species of Rhipicephalus were recorded from ten species of small mammals. Both larvae and nymphs of Ixodes ceylonensis, Rhipicephalus spp. and nymphs of Haemaphysalis hystricis and Hyalomma brevipunctata were recorded. Four species of fleas were recorded from five species of small mammals. Both male and female fleas of Stivalius phoberus, Stivalius aporus, Lentistivalius ferinus and male Nosopsyllus tamilanus were recorded. All species of ticks and fleas reported here have been previously recorded from Sri Lanka. However, we report new host species for I. ceylonensis (Crocidura miya, Suncus montanus and Solisorex pearsoni), S. aporus (S. montanus and Mus fernandoni), N. tamilanus (S. pearsoni) and Rhipicephalus spp. (Crocidura hikmiya, S. montanus, S. pearsoni, M. fernandoni), all of which are endemic mammals. Nosopsyllus tamilanus which was not recorded from shrews previously, is reported from the endemic shrew, Solisorex pearsoni in this study. Identity of Rhipicephalus spp. is yet to be confirmed. Its larvae were identified as belonging to R. ramachandrai, which is not reported from Sri Lanka hitherto. This species, originally described from India are reported from several small mammal species, which are also found in Sri Lanka. The nymphs of Rhipicephalus spp. were identified as belonging to Rhipicephalus haemaphysaloideus group, which includes R. haemaphysaloideus, R. pillans and R. ramachandrai.
Antioxidant activity and total phenolic content of Mee (Madhuca sp. ) oil
(The University of Peradeniya, 2013-07-04) Bopitiya, Dilini; Madhujith, Terrence
Mee oil, also known as Mahua oil extracted from the kernels of Mahua seeds (Madhuca species), is a highly unsaturated edible oil rich in monounsaturated fatty acids (MUFA). It is also rich in many bioactive compounds including phytosterols, sterol esters, triterpene alcohols, gamma-oryzanol, tocopherols, tocotrienols and other phenolic compounds. Furthermore, Mee oil is reported to have a high medicinal value. Minor components, especially antioxidative constituents, play an imperative role in nutrition and health. This study was carried out to determine the antioxidant activity and total phenolic content of oil extracted from Mee (Madhuca sp.) seed kernel which currently remains as an underutilized edible oil in Sri Lanka. The phenolic fraction of the oil was extracted into methanol by passing the oil through a glass column containing silica (60 Å pore diameter). The Total Phenolic Content (TPC) was determined using the Folin-Ciocalteu’s colorimetric method and expressed as mg of gallic acid equivalents (GAE) per gram of extract. The antioxidant potential of the oil extracts was assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging assays and β-carotene/linoleate model system using α-tocopherol as the reference antioxidant. The dose dependant behavior of the extract towards DPPH and ABTS radicals was also determined by using varying quantities (0.1 – 0.5 g) of the extract. Mee seed oil extracts possessed TPC of 13.00±0.05 mg GAE/g extract. The DPPH radical scavenging activity expressed as IC50 value of the oil extract and α-tocopherol was 0.078 mg/mL and 0.031 mg/mL, respectively. Oil extracts showing an IC50 value of less than 1mg/ mL are categorized as oils with considerably high antioxidant potential. The corresponding values for ABTS radical scavenging activity of Mee oil extract and β-carotene were 46.0% and 64.0%, respectively, at 2.0% (w/v) concentration. Mee seed oil extracts exhibited a slightly lower percentage of inhibition of linoleic acid induced oxidation of β- carotene (45.1%) compared to α-tocopherol (54.0%) at 2.0% (w/v) concentration. It was observed that the antioxidant efficacy of the extract as measured by DPPH and ABTS radical scavenging assays increased with the quantity of the extract confirming that compounds present in the extract contribute to the antioxidant activity of the oil. The results revealed that the Mee oil possesses a high antioxidant efficacy thus, it can be considered an edible oil with potential health benefits.
Classroom teaching and learning processes : realities in the lesson planning stages
(The University of Peradeniya, 2013-07-04) Embekke, E. K. S. K.
Good lesson planning is essential in teaching and learning. All good teachers have some type of plan when they walk into their classrooms to ascertain what students need to learn and how it will be delivered effectively during the class time. Successful planning of the teaching and learning process comprises several stages. The most common planning stages followed by teachers are “yearly planning”, “term planning” and “lesson planning”. The main objective of this study is to observe through a selected sample both how far these stages are practiced by teachers and to identify their advantages and disadvantages. This is an ethnographic study conducted using 8 schools in the Kandy District which represented different social class backgrounds. The research sample comprised 32 teachers and 250 students in grade 8. The sample of teachers was selected covering four subjects, Science, Mathematics, Sinhala and English. From each school, one teacher was observed for each subject over four lessons. Consequently, a total of 128 lessons were observed in this study. The researcher collected data from analyzing documents and by interviewing students and teachers. This enabled the researcher to triangulate and maintain the reliability and the validity of the data. The data collected in the research revealed that none of the teachers followed a “yearly plan” while a majority did not resort to “term planning” or “lesson planning”. Consequently, they were prone to feel helpless in new or odd situations, took more time to explain simple topics, lacked flexibility in delivering the lesson and made the teaching process more difficult overall. However, a few teachers who prepared complete lesson plans claimed that proper planning prior to teaching helped them to stay on track while achieving their objectives, saved time, helped them visualize the teaching process in advance and provided a good record of their own performance and built self-confidence. To minimize the weaknesses and drawbacks of the existing system, the researcher suggests that close monitoring of teacher activities in the planning stage is essential and recommends improving their knowledge on lesson planning through various teacher-education institutions.
Plastic responses in morpho-physiological traits of Codiaeum Variegatum "Pictum" in response to light heterogeneity
(The university of Perdeniya, 2013-07-04) Devi, M. I.; Weerasekara, W. A. C. S.; Benaragama, C. K.
Codiaeum variegatum ‘Pictum’ is an evergreen shrub of the family Euphorbiaceae which is highly popular among tropical landscape gardeners valued for its striking foliage. As most of the tropical landscapes demand low maintenance, it is important to evaluate the suitability of ‘Pictum’ as a low maintenance landscape (extensively managed garden) plant. Phenotypic plasticity is one of the phenomena that can be used to measure whether an individual can maintain stability in the face of environmental stresses. Plants that can tolerate varying environmental influences without altering much of their aesthetics are the best performers for low-maintenance landscapes. Therefore, this study was conducted to assess the suitability of C. variegatum ‘Pictum’ as a low maintenance landscape plant using the phenotypic plasticity index (PPI). The research was carried out at Kiribathkumbura, Kandy. Uniform sized export quality plants were planted in plastic containers filled with the standard medium. The plants were exposed to different levels of light; full sunlight (open), garden green shade net (green), commercial 50 % black and 80 % black shade nets. Different morphological and physiological parameters were measured and PPI’s were calculated for all the parameters. Finally the aesthetic quality was assessed. The results of this study revealed that total leaf area and total leaf dry weight were the traits that showed the highest plasticity among all phenotypic traits measured under the four light conditions (p<0.05). Plants had highest adaptability to alter root length under all light levels except 50 % shade, having high PPI values. Under open field and green net conditions, plant height showed a higher plasticity while a moderate plasticity was observed under 50 % and 80 % shades. Furthermore, leaf length was moderately plastic for all the treatments while leaf width was moderately plastic only for green and open fields. In addition, shoot dry weight was a rigid trait under all light conditions. Interestingly, total chlorophyll content under open field condition was almost non-plastic (PPI<0.15) compared to other three treatments. However, the overall PPI values of total chlorophyll were less plastic. All the traits assessed in the experiment showed variable degrees of phenotypic plasticity in response to different light conditions. A higher number of traits tested were highly or moderately plastic without compromising its aesthetic quality revealing that the plant can be established in different light environments, showing its suitability to low maintenance landscapes.
Growth responses of tea (Camellia Sinensis L.) nursery plants to vermiwash application
(The university of Perdeniya, 2013-07-04) Kumara, K. A.; Mohotti, A. J.; Ariyarathna, M.; Mohotti, K. M.
The high cost of agrochemicals and their unfavorable effects on human health and the environment have initiated a shift from conventional agriculture to organic agriculture. Vermiwash is one of the potential nutrient sources for organic tea cultivation. However, there has been limited work done so far on its effects on tea growth. This study investigated the potential of vermiwash application as a biofertilizer for tea nurseries. An experiment was conducted in the glass house of the Department of Crop Science, Faculty of Agriculture, University of Peradeniya, using three month old nursery tea plants (cultivar TRI 4006) planted in soil filled polythene bags. Four treatments were used: T1: Application of recommended nursery tea fertilizer (T65) alone, T2: vermiwash alone as a foliar application, T3: vermiwash foliar application with half-dose T65, and T4: no application of fertilizer or vermiwash (control). One plant was considered as an experimental unit and 24 replicates were allocated per treatment. Treatments were arranged in a completely randomized design. Treatment applications were done at two week intervals and plants were randomly rearranged weekly. Plant growth parameters were measured weekly and after 8 weeks, 8 plants from each treatment were destructively sampled. Growth parameters, fresh and dry weights, leaf nutrient and chlorophyll contents were measured. Data were analyzed using SAS. Vermiwash applied tea plants performed equally well compared to the recommended fertilizer treatment in terms of the measured parameters. The differences were not statistically significant amongst treatments, except for the leaf N content. Significantly high leaf N content was observed with T1 followed by T2 and T3, while T4 had significantly lower leaf N. The leaf N contents in T2 and T3 were higher than the minimum requirement of leaf N (3%). Vermiwash is known to contain microflora such as Azotobactor, Agrobacterium and Rhizobium. The presence of these microbes may convert organic nitrogen, amino acids etc. to available forms for plants through ammonification and nitrification processes. Leaves that developed with the recormended fertilizer mixture had the highest levels of chlorophyll a, b and total, followed by vermiwash + half – dose T65, and then plants treated with vermiwash only, with the control plants having the lowest. Vermiwash gave equally good results compared with the artificial fertilizer. Vermiwash was also able to reduce 50% of T65 fertilizer without affecting growth. The results were not statistically significant, which could be due to application of treatments for a short period of time. Hence, it will be useful to continue this experiment for a longer duration.
A retrospective study on dirofilariasis in five districts in Sri Lanka
(The University of Peradeniya, 2013-07-04) Iddawela, W. M. D. R.; Adicarum, D. R. S.; Ranaweera, R. L. A. R.
Dirofilaria repens is the most important cause of human dirofilariasis in Sri Lanka. It occurs commonly in adults except in Sri Lanka, where children younger than nine years are likely to be infected. The present study was carried out to describe the patient and parasitic factors associated with human dirofilariais in Sri Lanka. A retrospective descriptive study was conducted in 80 samples of worms, referred by surgeons in Badulla, Kandy, Kegalle, Monaragala and Polonnaruwa during the past five years. Data on age, sex and site of lesion were obtained from the details given in the referral letters. Morphological identification of the worm was based on the maximum width, length and the characteristic cuticle with sharp longitudinal cuticular ridges. Sex of the worm was determined by the width, length and distance between anterior end and genital opening. The age of the patients ranged from 8 months to 60 years. Of the study group, 69% were less than 40 years of age and 50.7% were males. Out of 80 patients, 34.5 %( 27) of the patients were less than 10 years of age. The youngest patient was 8 months. The majority (46%) of the patients were from the Kandy district. Nodules were reported in the abdominal wall (2), eye (35), face (4), foot (4), hand (3), leg (3) and scrotum (24). The largest proportion (65/80) were subcutaneous nodules. The adult worm was found in the upper part of the body in 85.6%, eye being the commonest site (41%). The scrotum was the commonest site in the lower part of the body (23.9%). Out of all adult worms, 80.8% were females while 11.5% were male worms. Only one nodule in the eye had both male and the female worms. The average lengths of the female and male worms were 12.1cm and 7.47cm, and average widths of female and male were 478.3 cm and 405.6 cm respectively. In conformity with these morphological characteristics, the filarial worms identified in these patients were Dirofilaria repens. The active age group (< 40 years) was the most affected. There was no difference in incidence between the two sexes. This pattern was seen in the studies done in the last decade of the 20ᵗʰ century. Sri Lanka is an endemic focus of human dirofilariasis due to D. repens. Therefore, dirofilariasis should be included in the differential diagnosis of patients presenting with subcutaneous nodules at any site of the body.
Microhabitat affinities of five small mammal species in two habitats at lower Hantana Peradeniya
(The University of Peradeniya, 2013-07-04) Bandara, N.J.; Meegaskumbura, Suyama
Microhabitat affinities of animals are important in wildlife management and conservation practices. The scale at which they operate dramatically affects the use of habitats by them. The objectives of the study were to monitor microhabitat affinities of small mammals in a pine plantation and a secondary forest and to compare differences in utility of microhabitats by them, between the two habitats. Small mammals were sampled using hair tubes. A total of 80 hair tubes, 40 in each habitat were placed every month for four consecutive days each month from November 2011 to March 2012. Traps were placed in a 10x10 meter grid. For each trap location eighteen descriptive microhabitat variables were recorded, which were analyzed using Principal Component analysis to deduce the microhabitat preferences of small mammals. Five small mammal species, Mus musculus, Rattus rattus, Rattus norvegicus, Bandicota indica and Ratufa macroura were recorded from both habitats. In the forest habitat both M. musculus and R. macroura showed a clear preference for microhabitats without overstory trees but with fallen logs and shrub cover, while the other three species showed a preference for microhabitats with herbaceous stems, tree stumps, overstory trees and woody stems. In the pine plantation all five species showed a common preference for areas with exposed soil surface and fallen logs. Though this was a short term study, it provides important data on the use of two habitats and microhabitats in them by five species of small mammals. Due to the availability of diverse microhabitats in the secondary forest, partitioning of microhabitats among small mammals was observed, while in the more uniform pine plantation all five species used the same microhabitat. Similar use of dense ground cover by M. musculus is well documented in previous studies. Ratufa macroura, being a strictly arboreal species, was an unexpected record. No previous microhabitat studies are available for this species. Rattus rattus is recorded as a finer spatial scale species sharing a common preference for fallen logs and woody plants and to avoid leaf litter, as observed here. In general R. norvegicus is regarded as a riparian specialist. Finding more hair samples of this species in the secondary forest, which is closer to the Sarasavi stream, supports this observation. There are no previous studies on microhabitat affinities of B. indica. In the present study they preferred relatively open areas with tree stumps and herbaceous stems.
Accumilation of Nitrate in selective crops and well water in Kalpitiya as affected by chemical fertilizer inputs
(The University of Peradeniya, 2013-07-04) Dissanayake, D. M. P. D.; Rajapaksha, R. M. C. P.
Chemical fertilizers, particularly nitrogen based fertilizers are known to contaminate soil, food and water and affect environmental health. This study was conducted to assess the impact of different fertilizer application practices on the nitrate () accumulation in selective crops under controlled conditions and levels of in well water in the Kalpitiya area. A pot experiment was conducted using Sandy Regosols collected from the Kalpitiya area. Onion, capsicum and radish were grown with three different fertilizer practices as recommended by the Department of Agriculture (DOAR), namely fertilizer mixture of CIC Agribusiness (Pvt.) Ltd. (CICR); and fertilizer regime practiced by the farmers (FP) for each crop. The plants were uprooted eight weeks after planting and fresh weight recorded. Sub samples were chopped, in tissues was extracted with water and assayed colourimetrically. Samples of selected crops collected from different farms at Kalpitiya and markets in selective cities were analyzed for content. Eighteen well water samples were collected from different locations in the Kalpitiya area and they were analyzed for and content. Mean comparisons were done by Duncan’s New Multiple range test at a significance level of 0.05 using the statistical software SPSS. Total content in the onion plants and capsicum pods were in the order of FP> CICR> DOAR which is the same order with respect to the quantity of fertilizer addition. The Nitrate content in onion and radish did not differ between fertilizer treatments. The content in almost all the onion and radish samples were within the range of 1000-2500 mg/kg which is considered as ‘high’ category. Organically grown onion leaves (706 mg/kg) and bulbs (898 mg/kg) showed significantly lower contents. Among the crops tested, onion accumulated more and among the fertilizer practices, FP resulted in comparatively higher levels. The contents of the market samples were not above the maximum permissible levels introduced by different countries. Among 12 water samples used for domestic purposes, three showed levels above 1.5 mg/L and seven showed levels above 10 mg/L which are the maximum permissible levels recommended by World Health Organization. All the water sources used for irrigation showed levels higher than 10 mg/L suggesting that the ground water has been contaminated heavily with fertilizer residues.
An assessment of the stress levels of captive elephants held under different management conditions using serum cortisol levels
(The University of Peradeniya, 2013-07-04) Mel, R. K. De; Kumara, M. R. D.; Dangolla, A.; Jayasekera, J.; Nanayakkara, D. K. K.; Rajapakse, C.; Ratnasooriya, W. D.; Weerakoon, D. K.
Captive elephants are susceptible to various stresses present in their captive environment. The level of stress experienced by captive elephants could vary between different facilities depending on the management practices adopted. This study was conducted to test the hypothesis that stress levels experienced by captive elephants vary between captive facilities with different management practices in Sri Lanka. The elephants for this study were from the National Zoological Gardens, Pinnawela Elephant Orphanage and Millenium Elephant Foundation, facilities that have distinctly different captive management practices. Animals at the National Zoological Gardens are kept chained most of the day. Elephants at the Pinnawala Elephant Orphanage are allowed to walk and engage in intra-specific behaviours. Elephants at the Millennium Elephant Foundation are used for tourist rides. Therefore, the highest stress levels were expected at the National Zoological Gardens and the lowest at Pinnawela Orphanage. The stress levels of elephants from the above three facilities were determined by measuring their serum cortisol levels using radio-immunoassays. First, diurnal changes in the serum cortisol level of elephants were determined, at four hour intervals, to identify the peak secretion time. Next, serum cortisol levels at the peak secretion time of elephants from the three facilities were determined. Peak mean serum cortisol level (132.38 nmol/L, n=5) was observed at 0800h, which is consistent with observations made elsewhere for elephants. Therefore, 0800h was chosen as the optimum sampling time for the cortisol-based stress study. In contrast to our prediction, there were no significant differences (Kruskal-Wallis, H=1.71, df=2, P > 0.05) among mean serum cortisol levels of the elephants at the National Zoological Gardens , Pinnawala Elephant Orphanage and Millennium Elephant Foundation . Therefore, it can be concluded that there is no difference in the cortisol-mediated stress response in elephants held under these three different captive conditions.

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