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.
A study on the impact of the grade five scholarship examination on the self-concept of the students
(The University of Peradeniya, 2013-07-04) Balasooriya, R. M. J. W.; Bandarathilake, K. W. A. C.; Premarathne, Y. G.; Wanninayake, H. M.; Wanninayake, W. M. M. P. K.; Senevirathna, Walter
The objectives of this study were to identify the level of self-concept and gender differences of those who pass and fail the year five scholarship examination and to identify the perception of teachers and parents about these students’ talents and skills. A mixed research methodology was adopted in this study. A deliberate sampling method was used to select 110 (n=110) students from a National school (1AB) and a Junior school (Type 2) in the Nikaweratiya Educational Zone in the Kurunegala district. A similar sampling method was used to select ten teachers (N=10) and ten parents (N=10) from the same schools. The survey was conducted among the students to measure their self-concept dimensions by using a questionnaire that was developed through the Fleming Courtenay revision of the Janis Field scale - 2005. Apart from this, the parents and the teachers were interviewed. Data were analyzed using both qualitative and quantitative methods. Three null hypotheses were derived from the quantitative data and these hypotheses were tested using a chi-square test, t-test and Pearson’s correlation test. Qualitative data were analyzed using thematic analysis. According to the results the first null hypothesis namely, ‘there is no significant connection between the levels of self-concept of students and their achievement at the year five scholarship examination’ (the chi-square value counted was higher than the theoretical value (9.49<112.239)) was accepted. The other two null hypotheses namely, ‘there is no significant connection between the self-concept levels and the gender differences of the student sample’ (the chi-value countered was lower than the theoretical value (3.14>1.009)) and ‘there is no significant difference between the self-concept scores and the year five scholarship examination marks’ (the calculated t- value of two tailed test was higher than the theoretical value (5.095>1.980)) were rejected. According to the cross tabulation, those who obtained high marks at the year five scholarship examination, had a high level of self-concept scale values. Meanwhile, according to the Pearson’s correlation results, there was a slightly positive correlation (r=0.18) between the year five scholarship marks and the self-concept marks of the student sample. Moreover, the parents of the students who passed the year five scholarship examination and also those of the failed students shared the idea that their children were eager to resume their studies soon after the examination. The interviews with the teachers too revealed that soon after the examination the active participation and active learning nature of the both, students who had passed the examination and those who had failed had increased.
Development of analog and digital input output data and ethernet network interface device
(The University of Peradeniya, 2013-07-04) Arachchi, I. T. G. B.; Samarasekara, C. S.; Silva, M. R. De; Samaranayake, B. G. L. T.
Over the past few decades, the internet has grown to become one of the pioneering information providers for the entire globe. Currently, it serves the visual, auditory and mental needs of millions of its users by hosting videos, audios and online text. In addition, it offers a widely expanded and well established computer network platform to communicate data from sensors to monitor processes and send signals to control such processes. Until the recent past, such ideas were not considered attractive because of issues in network reliability, real-time delivery and hardware accessibility. While the first two issues have been addressed by various researchers and an ample amount of solutions have been developed and installed, this paper presents an approach from scratch carried out at undergraduate level to interface sensors and actuators to Ethernet physical layer and hence address the hardware accessibility problem. The designed and implemented electronic hardware consists of analog and digital signal interfaces to a stand -alone network connectible hardware unit. The unit consisting of two interfaces can be configured, controlled and used for communication from a remote server in the computer network. The design of this hardware unit opens up new opportunities in the industry and extends its current capabilities in the factory floor level, which enables a single protocol covering distributed control systems, maintenance and monitoring of processes and system administration. Even though the capability of the Ethernet for time critical applications has been proved both theoretically and experimentally, due to market monopoly maintained by well established vendors, it is still difficult to convince the potential to many real-time industry applications. However, a less exhaustive approach would be to introduce the Ethernet through an Analog and Digital Input Output Data unit presented here for non-time critical applications. An area of very high potential would be building management systems, where the network backbone is inherently the Ethernet.
Factors associated with denture induces stomatitis : a comparative study
(The University of Peradeniya, 2013-07-04) Thilakumara, I. P.; Jayasooriya, P. R.; Jayatilake, J. A. M. S.; Abeypala, G. A. K. K.; Pallegama, R. W.
Denture induced stomatitis (DIS) is a medical problem in adult denture wearers which is commonly associated with Candida. Oral Candida may be associated with hand carriage and candidal infections in other parts of the body. Therefore, this study aimed to assess the factors associated with DIS and the oral and hand carriage of Candida among the patients with and without DIS attending the Dental Hospital (Teaching), Peradeniya. Sixty two complete or partial denture wearers with DIS were included in the test group and 30 comparable patients without DIS were included in the control group. Socio-demographic data, medical and dental history and denture and oral hygiene habits were assessed using a pretested interviewer administered questionnaire. Clinical examinations were performed to assess DIS. Oral and hand Candida was quantified in terms of colony forming units after fingertips and oral rinse culture on Sabourad’s dextrose agar (SDA). Identification of Candida was based on colony characteristics and Gram’s stain. In the test group, 45 (72.6%) and 17 (27.4%) patients had upper complete and partial dentures respectively. In the control group, 14 (46.7%) and 16 (53.3%) patients were complete and partial denture wearers respectively. Among the DIS patients, 34 (54.8%) were also wearing lower dentures, but DIS was not related to any of the lower dentures. Use of dentures during sleep showed a significant relationship to the presence of DIS (Chi-square= 11.6, P<0.001). Newton type ΙΙ DIS was the most frequently observed clinical pattern (in 69.4% patients) and proportions of patients with type Ι and type ΙΙΙ DIS were equal. The odds (Odds Ratios) of carrying Candida in the hand by oral candidal carriers was 7.2 (95% CI 0.7, 66.6) for the test group and 8.6 (95% CI 8.7, 84.8) for the control group. In conclusion, use of dentures during sleep is a factor that predisposes patients for the occurrence of DIS. Oral Candida in denture wearers may lead to candidal hand carriage. An extended study with a larger control group is suggested for more concrete findings.
DNA markers for non-diabetic end satge kidney disease in the North Central Province, Sri Lanka : a pilot study
(The University of Peradeniya, 2013-07-04) Jeewantha, H. B. D.; Ranaweera, R. M. I. U.; Dayananda, A. G. M. L. K.; Dissanayake, D. M.; Goonasekera, C. D. A.; Sooriyapathirana, S. D. S. S.
Non-Diabetic Chronic Kidney Disease (NDCKD) is a devastating disease in the North Central Province of Sri Lanka. Currently the condition is fatal within a few years of diagnosis unless transplanted amidst meager resources. Providing palliative care with haemodialysis and mitigation therapy prolongs life for a few more years but has proved enormously costly consuming 4.6% of the annual healthcare budget. This is a huge burden to the Sri Lankan economy. In recent times, genome wide association studies have shown genetic loci underlying End Stage Kidney Disease (ESKD) in African Americans. Since then, DNA markers have been developed linked to ESKD. We tested these DNA markers amongst NDCKD patients and healthy people in Sri Lanka to identify the people at high-risk for NDCKD. Venous blood samples were collected from 100 patients with medical records obtained via the Epidemiology Unit, North Central Province and 10 control blood samples from volunteering healthy people following informed consent. Blood samples from 10 NDCKD patients and from 10 healthy people were used to screen the DNA markers. DNA was extracted from leucocytes of collected blood by using the QIAamp DNA purification system. PCR was carried out for 10 markers with genomic DNA as the template and the primer annealing temperature was . PCR products were size separated by using 1% agarose gel electrophoresis. The presence or absence of bands for each patient and healthy persons was recorded. Seven out of ten markers gave successful amplification in PCR. Except one allele, all the other alleles detected for seven DNA markers showed various degrees of polymorphisms. These polymorphic bands provide a platform to analyze the pedigrees of families where NDCKD is prevalent.
Degradation of carbofuran in a sandy regosol and residue levels in selective crops
(The University of Peradeniya, 2013-07-04) Jeyaluckshinee, T.; Rajapaksha, R. M. C. P.
The indiscriminate use of pesticides in agriculture has resulted in detrimental effects on soil quality and human health. Carbofuran is one of the most toxic and widely used pesticides in Sri Lanka. This study was conducted to assess the degradation of carbofuran in a sandy regosol and carbofuran residue in selective food crops grown in carbofuran contaminated soil and available in the market. Soil was collected from a field exposed repeatedly to carbofuran in Batticaloa. An incubation experiment was conducted by contaminating soils with carbofuran at four different rates; 10 mg/kg as recommended by the Department of Agriculture (DOA), 20 (DOA×2), 50 (DOA×5) and 300 (DOA×30) and replicated thrice. Contaminated soils were incubated in vitro and sub samples were taken on 3rd, 7th, 14th, 21st and 28th days after contamination. They were extracted with chloroform and carbofuran was analysed using a colourimetric method. For the pot experiment, brinjal, onion and chilli were grown in some soils contaminated with carbofuran at 20 kg/ha (DOA recommendation) and 40 kg/ha as farmers practice (FP). Plants were uprooted at 8 and 11 weeks after planting (WAP). Samples of vegetables were also collected from markets in Batticaloa and Kandy, a homegarden and an organic farm. They were assessed for carbofuran residue in the chloroform extractable fraction using colourimetric method. Mean separation was performed in Duncan New Multiple Range Test using SPSS software. The chloroform extractable carbofuran was about 2-5% of the initial concentration in all treatments at the 28th day of contamination. Complete dissipation of carbofuran applied at 10 -300 mg/kg into the experimental soil did not take place over a period of 28 days. Carbofuran accumulation in experimental crops was proportionate to the rate of application. The highest carbofuran residue level was recorded for onion (13.2 mg/kg) in the FP treatment and in onion leaves (5.49 mg/kg) collected from the Kandy super market. The carbofuran residue levels of samples collected from the home garden and the organic farm was below the detectable quantity. Although carbofuran is not recommended for chilli, an extremely high residue level was observed in chilli (17.87 mg/kg) collected from the field in Batticaloa. Carbofuran residue levels of market samples varied from 0.3 to 5.5 mg/ kg fresh weight and all samples except one exceeded the maximum residue level recommended by European Union standards (0.2- 0.5 mg/kg).
In vitro antimicrobial activity of leaf exreacts of Magifera zeylanica
(The University of Peradeniya, 2013-07-04) Dhanarisi, H. K. J.; Jayatilake, J. A. M. S.; Adikaram, N. K. B.
Natural products have been used as a source for many drugs from the very dawn of medicine. With the evolution of resistance by microorganisms to present antimicrobials, the need for novel discoveries is urgent. Many researchers have demonstrated antimicrobial effects of Mangifera indica plant extracts. This study was undertaken to find out the antimicrobial activity of leaf extracts of Mangifera zeylanica which is an endemic plant in Sri Lanka. The leaves of a Mangifera zeylanica plant (identity confirmed) were collected from the Gannoruwa forest. Leaf extracts were prepared by the maceration method using water at room temperature, water at celsius 70, boiled water and ethanol. Antimicrobial effect of the plant extract at a concentration of 25mg/ml was tested against six isolates of bacteria; Staphylococcus aureus (NTCC 6571), Escherichia coli (NTCC 10417), Pseudomonas aerugenosa (NTCC 10662), Streptococcus pyogenes, Enterococcus faecalis and Methiciline resistant Staphylococcus aureus (MRSA) and five species of Candida; Candida albicans (ATCC 90028), Candida parapsilosis (ATCC 22019), Candida krusei (ATCC 6258), Candida glabrata (ATCC 90030), Candida tropicalis (ATCC 13803) using the agar well diffusion method. Minimum inhibitory concentrations (MIC) were determined for the extracts with high activity using the agar dilution method. When the diameter of the zones of inhibition was considered, the highest antimicrobial activity was detected against S. aureus followed by E. faecalis, E. coli and P. aerugenosa. Noticeable antimicrobial activity was detected against C. parapsilosis, followed by C. glabrata, C. krusei and C. tropicalis except C. albicans. Ethanol and celsius 70 water extracts showed higher antimicrobial activity. For the ethanol extract, the MIC value for both S. aureus and MRSA was 0.2 mg/ml. E. faecalis had a MIC value of 0.8 mg/ml. The MIC value for P. aerugenosa was 1.6 mg/ml and for E. coli MIC was 3.2 mg/ml. MIC value for C. krusei, C. prapsilosis and C. glabrata was 0.1mg/ml while the MIC value for C. tropicalis was 12.8 mg/ml. For the celsius 70 water extract, both S. aureus and MRSA showed a MIC value of 0.4 mg/ml. MIC value for E. faecalis was 1.6 mg/ml. MIC value for C. prapsilosis was 0.1mg/ml and the MIC value for C. krusei was 0.2mg/ml. C. glabrata had a MIC value of 0.8 mg/ml. Leaf extracts of Mangifera zeylanica under different conditions, exhibit marked antimicrobial activity. Ethanol and celsius 70 water extracts are effective against many microorganisms including S. aureus, E. faecalis, P. aerugenosa and non-albicans Candida.
Effective use of storage available on PCS in a lab environment
(The University of Peradeniya, 2013-07-04) Yamuna, S.; Tharmini, T.; Maraikar, Ziyan
In many departments, a quota system is used to divide storage among the users due to the limited amount of storage available. A problem occurs when a user exceeds the maximum allocated space. Our aim is to provide a solution to manage the storage in such a network. Even though there are many existing distributed storage systems in the world such as Bit Torrent, BigTable, Wuala, etc, this is a distributed storage system for a particular Local Area Network (LAN), consisting of many PCs. The ultimate goal of this project is to optimize the use of resources available in order to resolve the storage problem. About 60% of storage space is not used in our department's laboratory computers as the operating system occupies only a small amount of hard disk. Thus, the proposed system uses those unused storage spaces as nodes, but the whole system appears to outside as common storage. The system consists of two major components, a centralized database and storage nodes. The Lab machines are considered as storage nodes and a server is operated as a centralized database to keep a record of all the transactions and the details of each machine. In order to provide replication facility, our system stores the file in two nodes. Therefore the system will be capable of retrieving the data even if one node goes down or offline. This ensures safe keeping and load balancing. Currently the system is capable of updating the database periodically, file transferring and retrieving files. However, there is no guarantee of security, because the system does not use encryption method. Another drawback is transferring of large files. In order to transfer a file successfully, the size of that file should be less than the free space on a single machine. But it is possible to enhance the system to transfer a larger file by splitting the file and store in multiple nodes, and then combine the sub-files together at retrieval. The actions such as encryption, splitting and merging are not implemented in the current system and will be incorporated in the next phase of this project.
Modelling of dielectric response of generator stator insulation
(The University of Peradeniya, 2013-07-04) Naranpanawe, W. M. L. B.; Rathnayake, R. M. H. M.; Bowala, D. K.; Fernando, M. A. R. M.; Jayantha, G. A.
Service life of a generator stator winding mostly depends on the condition of its insulation. Therefore, condition assessment of stator insulation is very important to prevent unexpected failures of generators. Non-destructive tests are usually conducted to assess the condition of such stator insulation, and among them, Frequency Dielectric Spectroscopy (FDS) measured in the frequency domain, has been proven as an effective test method to obtain the dielectric response of the insulation. This work aims to increase the understating on dielectric response of generator stator insulation under drying, wetting and ageing conditions. This paper presents modeled results representing the dielectric response based on FDS measured on aged and non-aged asphalt-mica, polyester-mica and epoxy-mica insulated winding samples. In the ageing tests, 40 cm long asphalt-mica and epoxy-mica samples (two each) were electrically stressed at 300% of their nominal voltage in a cyclic behavior (each day stressing and resting as 12/12 hours.) for more than 1800 hours. For the non-ageing test an asphalt-mica winding was dried at 80C inside an oven (2.6 m x 1.7 m x 0.8 m) for 72 hours. For wetting, a polyester-mica winding was dipped in a water bath for 168 hours at room temperature. The FDS measurements were conducted on the samples every 168 hours. All tests were done at 200 V from 1 kHz to 0.1 MHz with a three electrode system using Insulation Diagnostic Analyzer (IDA200). In the modeling part, first the complex permittivity ( ) was obtained from the measured FDS results. The dielectric response function was obtained from the inverse Fourier transform of real part of the susceptibility. The DC conductivity (σ) was also calculated from the permittivity and the Kramers – Kronig (K-K) relationship. The dielectric response function was modeled by Curie-Von Schweidler (.) model. Thus for each FDS results the dielectric response is characterized by permittivity (), conductivity (σ) and dielectric response function A and n. It was found that the condition of stator insulation can be modelled by dielectric response parameters. Further, the dielectric response function shows good agreement with all tested cases whereas the conductivity clearly highlights the variation in cases of ageing and drying.
Megaoesophagus in dogs due to seperation anxiety: two clinical cases
(The University of Peradeniya, 2013-07-04) Dilshani, K. W. W.; Dangolla, A.; Abeygunawardana, H. E.
Megaoesophagus in adult dogs usually has an idiopathic aetiopathology. However, recent studies indicate that the abnormality appears to be neurogenic rather than myogenic. The two cases presented here provide positive evidence on the development of megaoesophagus due to separation anxiety. In both cases, antidepressants fluoxetin and citalopram were used with a satisfactory response. “Billy”, an eight-year-old male Labrador was presented to the Veterinary Teaching Hospital (VTH) with complaints of lethargy and severe regurgitation. Billy was brought up for seven years with his littermate who died one year previously. Thereafter, Billy received less care and was kept in an outdoor-cage. Megaoesophagus was confirmed by contrast radiography. Billy was given more attention, and metoclopramide was administered orally (1mg/kg) 45 minutes before meals. He was fed with small quantities of solid food four times daily using an elevated feeding position and was kept in this position for 20 minutes afterwards. He showed an impressive recovery. Four months later, Billy returned with the same complaint, was hospitalised and managed similarly. In addition, citalopram was given twice daily (1mg/kg). Six months later, Billy is doing well. “Jake”, a nine-year-old male Labrador, was presented to the VTH with respiratory distress and severe regurgitation. One month before presentation, the owner with all the family members returned after a three-month absence during which time Jake was managed by a helper who had known him for several years. When Jake was brought to the clinic, he could not walk, was agitated and his heart rate rapidly increased by almost any movement of an object or person. Megaoesophagus was confirmed by contrast radiography. Jake was managed in the manner described above, after discharge. The owners made alterations in their daily routine, and Jake was on antidepressant medication (fluoxetine 20mg/kg). Four months later, Jake is doing well, has less regurgitation, is less excitable and joins the client in their daily evening walks as usual. The two cases described above indicate that separation from loved ones could influence the development of megaoesophagus. The use of antidepressants in these two cases were helpful in management of clinical signs.
Status of the quality of water in the main canals and tributaries of the Mahaweli river during the dry season
(The University of Peradeniya, 2013-07-04) Aravinna, A. G. P.; Priyantha, N; Pitawala, H. M. T. G. A.; Yatigammana, M. W. S. K.
The Mahaweli Left Bank Canal (MLBC) and Mahaweli Right Bank Canal (MRBC) which originates at the diversion structure at Minipe, provide water for paddy cultivation in the Mahaweli system C and E of Sri Lanka. The areas fed by the MLBC and MRBC are 7,020 ha and 30,760 ha, respectively. The total length of the unlined MLBC is 74.2 km, while a 65 km section of the MRBC is lined up to Weera Wewa. A considerable fraction of the catchment of the Mahaweli river (MR) is utilized for agriculture, and consequently, the quality of water (WQ) of the downstream of the diverted MR could be expected to be adversely affected. Nine locations along the MLBC, Heen Ganga, (a tributary contributing its flow to MLBC), eight locations along the MRBC, Loggal Oya and Ulhitiya Oya (two tributaries contributing to MRBC) were selected for WQ monitoring during the dry season (August 2012), and representative grab samples were collected on two occasions at each location. Sample collection, transportation, storage and preservation were performed in accordance with standard methods. The pH and electrical conductivity (EC) were measured in situ and total dissolved solid (TDS), total suspended solids (TSS), chemical oxygen demand (COD), total hardness (as CaCO₃), chloride (Cl⁻), sulphate (SO₄²⁻), total dissolved phosphorous and total phosphorous were determined in the laboratory. Mean values of the above parameters along the MLBC were 7.4 ± 0.1, 0.12 ± 0.03 mS cm⁻¹, 73.8 ± 18.6 mg dm⁻³, 12.6 ± 6.9 mg dm⁻³, 7.0 ± 2.9 mg dm⁻³, 54.1 ± 17.5 mg dm⁻³, 5.7 ± 1.2 mg dm⁻³, 3.3 ± 0.3 mg dm⁻³, <0.1 mg dm⁻³ and 0.1 ± 0.0 mg dm⁻³, respectively. Corresponding values for the MRBC were 7.1 ± 0.1, 0.12 ± 0.01 mS cm⁻¹, 91.6 ± 5.8 mg dm⁻³, 16.4 ± 25.7 mg dm⁻³, 5.4 ± 3.6 mg dm⁻³, 44.2 ± 5.5 mg dm⁻³, 5.9 ± 1.1 mg dm⁻³, 3.4 ± 0.2 mg dm⁻³, <0.1 mg dm⁻³ and 0.2 ± 0.1 mg dm⁻³, respectively. Considerable changes in WQ were not observed along the MRBC although there were some fluctuations. An increasing trend was observed for hardness, EC, TDS and SO₄²⁻ along MLBC and this gradient estimated for TDS and hardness are 1.8 mg/km (R² ═ 0.655) and 1.7 mg/km (R² ═ 0. 881), respectively. Evaporation, anthropogenic activities and hydrological variations would be responsible for this increase and further investigations are being carried out for justification. Measured WQ parameters of MRBC, MLBC and Loggal Oya, Ulhitiya Oya and Heen Ganga are within the maximum permissible levels for drinking water defined by Sri Lankan Standards.
Response of copea to salinity during the first phase of salt stress development in the early vegitative stage
(The University of Peradeniya, 2013-07-04) Wijesinghe, R. M. L.; De Costa, W. A. J. M.
The overall objective of the present study was to determine the physiological basis of the response to salt stress in cowpea (Vigna unguiculata cv MI 35) during the first phase of salt stress development in the early vegetative stage. Two experiments were conducted with plants grown in hydroponic culture. The objective of the first experiment was to determine the responses to direct water stress and salt stress-induced water stress of equal osmotic potential. The second experiment was conducted with the objective of determining the effects of different containing salts (i.e. ) of equal osmotic potential on growth and physiology of cowpea. In the first experiment, NaCl and equivalent polyethylene glycol (PEG) treatments were started at the third tri-foliate leaf stage at 25 mM NaCl and increased by 25 mM steps to 75 mM at two-day intervals. In the second experiment, salt stress was induced at the same stage using equivalent concentrations of NaCl, giving equal osmotic potentials starting at 25 mM NaCl and increased at 25 mM steps at two-day intervals up to 100 mM. In both experiments, control treatments were maintained at 1 mM NaCl. The plants were harvested two days after application of the highest level of salt and water stress to ensure that they were within the first phase of salt stress. In the first experiment, both NaCl and PEG-induced stress did not cause significant influence on total plant biomass, but induced greater biomass partitioning towards roots, thus resulting in greater root biomass. This effect was greater in PEG-induced direct water stress than in the NaCl-induced salt stress. PEG caused significant reductions in leaf area per plant and specific leaf area indicating that direct water stress reduced leaf expansion and increased leaf thickness. Both stresses caused significant reductions in leaf net photosynthetic rate and transpiration efficiency with PEG causing a greater reduction than NaCl. It is concluded that cowpea is more sensitive to water stress than salt stress during its early vegetative stage with photosynthesis, leaf expansion and biomass partitioning to roots being more sensitive than total biomass accumulation. In the second experiment, none of the salt treatments caused a significant reduction in total biomass or root biomass during the first phase. However, leaf net photosynthetic rate, stomatal conductance, transpiration rate and transpiration efficiency showed significant reductions in all salt treatments relative to the control. The reductions were greatest under NaCl, followed by Na2SO4 and MgCl2 indicating that cowpea is more sensitive to Na+ than Cl- ions during the first phase of salt stress in its early vegetative stage. Analysis of salt ion concentrations in the leaves showed higher Na+ concentrations in the NaCl and Na2SO4 treatments and higher Cl- concentrations in the NaCl and MgCl2 treatments.
Does oxidizing power of roots affect the iron toxicity tolerance of rice?
(The University of Peradeniya, 2013-07-04) Wijerathna, Y. U. C.; Dandeniya, W. S.; Mithrasena, Y. J. P. K.
Iron toxicity decreases the average rice yield in the low country wet zone of Sri Lanka from its potential of 10 t ha-1 to 2.5 t ha-1. Management of iron toxic soils will not be successful until a clear understanding of the mechanisms to tolerate iron toxicity is gained. A study was conducted with the aim of determining the effect of the oxidizing power of roots on iron toxicity tolerance by rice. Three varieties of rice with varying iron toxicity tolerance were used in an experiment conducted at the Regional Rice Research and Developing Centre, Bombuwela. The varieties were Bw 267-3 (tolerant), Bw 272-6b (susceptible) and Bw 363 (moderately tolerant). Rice seedlings were grown in a nursery maintaining aseptic conditions. To test the iron toxicity tolerance by rice varieties 21 day-old seedlings were transplanted in sand culture maintained at saturated condition and enriched with three iron treatments; 0, 75 and 300 ppm of Fe2+ supplied as in four replicates. Plants were irrigated with standard IRRI solution with the respective iron treatment twice a week until 40 days after germination (DAG). At 40 DAG plants were uprooted and oven dry weights, shoot Fe, P and K contents were measured. Potential rhizosphere oxidizing power of three rice varieties was assessed following the method suggested by Trolldenier (1987). Analysis of variance was done to determine the significance of treatment effects and LSD was used for mean separation. At 40 DAG, the biomass production decreased by nearly 50% with increasing iron levels from 0 to 300 ppm in all three varieties. Bw 272-6b showed iron toxicity symptoms and higher tissue Fe2+ contents than the tolerant varieties but Fe2+ levels were not significantly different (p<0.05). There was a significant interaction between variety and iron treatment on nutrient uptake by rice (p<0.05). Oxidizing power of roots as indicated by the width of the clearing zone was significantly different among varieties. Tolerant Bw 267-3, had the highest oxidation potential (5.3±0.9 cm) followed by moderately tolerant Bw 363 (3.7±0.9 cm) and susceptible Bw 272-6b (2.5±0.6 cm). Hence, there is a positive relationship between oxidizing power of roots and iron toxicity tolerance. Even though the results from the present work suggest the use of oxidizing power of roots as a potential parameter for in vitro screening of a large number of rice varieties for iron toxicity tolerance, further studies with a larger germplasm with varying iron toxicity tolerance is recommended.
Conducting polymers from natural rubber via extended conjugation
(The University of Peradeniya, 2013-07-04) Bulumulla, C. D. B.; Bandara, H. M. N.; Bandara, B. M. R.
After the discovery of the world’s first conducting polymer- polyacetylene, many conducting polymers have been synthesized for use in several types of electronic devices. Conducting polymers are found in sensors, coatings, biocompatible polymers, batteries, display devices, actuators and many more. As conducting polymers are based on synthetic compounds, some undesirable properties such as reproducibility, stability, difficulty in synthesis, high cost and lack of biodegradability are associated with them. With a view to producing a conducting polymer, devoid of these undesirable properties of synthetic polymers, the conversion of natural rubber into a conducting polymer was explored. Natural rubber is a natural polymer abundantly produced in Sri Lanka from the latex of the rubber plant, Hevea brasiliensis (Euphorbiaceae). Natural rubber has the structure 1,4-cis-polyisoprene which may be converted into a conjugated polymer having conducting properties. However, defining the reaction conditions for the conversion is not straightforward because of the polymeric nature of rubber and its association with other compounds in natural form. As a model compound, squalene was selected as it has essential structural features of polyolefinic reactivity similar to that of natural rubber. Thus conditions were first defined for successful bromination of squalene and dehydrobromination of the product. Exhaustive bromination of squalene with Br2 furnished squalene dodecabromide. Dehydrobromination was achieved by heating a mixture of squalenedodecabromide and methanolic KOH under reflux. The reaction products derived from squalene were characterized using Fourier-Transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (1H-NMR) spectroscopy. Applying similar conditions on rubber latex that had been stabilised by formaldehyde and nitric acid, bromination of natural rubber was performed to obtain a white compound. Dehydrobromination of the white compound with sodium methoxide provided the conjugated polymer as a bright-yellow coloured compound. The reaction products derived from natural rubber were characterized using FT-IR and thermogravimetric analysis. The yellow polymer prepared from natural rubber displayed a conductivity of the order of after exposure to iodine vapour. To the best of our knowledge, this is the first report of a conducting polymer that has been obtained by chemical modification of a natural polymer.
Assessment of Pupal Parasitoid Guild of house fly (Musca domestica L. ) in low and mid country regions of Sri Lanka
(The University of Peradeniya, 2013-07-04) Rathnayake, R. P. R. S.; Hemachandra, K. S.; Wijayagunasekara, H. N. P.
The common houses fly (Musca domestica L.) (Diptera: Muscidae) is one of the most annoying insects in domestic habitats. The house fly population is a nuisance and it has long been suspected as a vector of several human and animal diseases. Accordingly, controlling of house flies is very important and integrated housefly management is regarded as the best approach. Biological control is one of the key elements of a successful integrated housefly management program. During recent times, the prospect of using parasitoids is higher than the other biological controlling agents and it has been practiced in North America and several other countries in the world. Although a considerable amount of research data are available on the global scale, no work has been done on these parasitoids of house flies in Sri Lanka. As the first step towards developing a biological control method for houseflies in Sri Lanka, this study was conducted in two locations in the mid- and low-country of Sri Lanka with the objectives of assessing the pupal parasitoid community associated with housefly pupae. Samples of housefly pupae were collected from two sites at Peradeniya, namely a goat rearing facility and a poultry rearing facility and two sites at Dankotuwa, a garbage dumping site and poultry rearing facility at two-week intervals from June to August, 2012. Collected pupae were placed in separate micro well plates and incubated under room temperature until the emergence of parasitoids. Emerged parasitoid species were identified using the taxonomic key of Rueda and Axtell and evaluated for their capacity of parasitism. Six species of parasitoids belonging to Family Pteromalidae were identified and their relative abundances were Spalangia cameroni Perkins (34.9%), Spalangia endius Walker (22.2%), Spalangia nigroaenea Curtis (33.3%), Spalangia drosophilae Ashmead (0.5%), Muscidifurax raptor Girault and Sanders (8.8%) and Nasonia vitripennis Walker (0.2%). Identities of S. cameroni, S. endius and S. nigroaenea were confirmed by the Natural History Museum in London. Out of these six species of parasitoids, S. cameroni, and S. nigroaenea were the most predominant parasitoids attacking the house fly pupae. The levels of parasitism on house fly pupae by parasitoids were different with sampling time throughout the survey and it varied with the geographical location in addition to its association with breeding habitats. Among the two sampling locations, Peradeniya had a higher level of total parasitism of house fly pupae (60.7%) as compared to Dankotuwa area (55.0%).
Evaluvation of genetic diversity in estate selections of tea (Camellia Sinensis L.) using floral characteristics and ssr markers
(The university of Perdeniya, 2013-07-04) Jayaweera, J. K. P. T. P.; Wickremasinghe, I. P.; Ranatunga, M. A. B.
Evaluation of genetic diversity of the tea germplasm is a vital requirement for its conservation and utilization in a tea yield improvement programme. The objectives of this study were to evaluate the genetic diversity of estate selections while investigating ancestral relationships among them and to compare the genetic relatedness with geographical locations using SSR markers. Fifty estate selections were selected to represent all the tea growing Agro Ecological Regions (AER) in Sri Lanka. The floral characterization was done using five standard morphological descriptors that revealed considerable variation among the estate selections. Correlation analysis among the floral traits illustrated a significant negative correlation between split pattern of style and style length/column length ratio. Floral data were subjected to Principle Component Analysis and 74% of the total variability was explained by the first two Principle Components. The resultant biplot clearly categorized estate selections into four groups viz Assam, China, Cambod and Assam – Cambod hybrids. A majority of the estate selections were grouped into Assam and Cambod types while China types were poorly represented in the germplasm studied. Highly informative eight SSR primers specially developed for the genus Camellia were used for the molecular assay which generated 33 polymorphic bands. The average polymorphism was 93.75% where the Polymorphism Information Content value for primers ranged from 0.5 to 0.91. Data obtained by the SSR primers were subjected to genetic variation analysis, according to which the diversity among the estate selections originating from different AERs ranged from 0.02 to 0.63. The population derived from the WM2a region clustered with the highest distance in the dendrogram indicating that this population is genetically diverse from the others. The dissimilarity matrix generated from the genetic variation analysis showed that genetic distance among estate selections ranged from 0.03 to 0.82 indicating wide genetic variation. Ten clusters were obtained for the cluster analysis and six estate cultivars (TC 10, CV 4B1, CH 13, QT 4/4, CV 5B1 and MO 241) were identified as diverse phenotypes in the neighbour joining tree and could be used as diverse parents in tea breeding programs after they have been evaluated for traits such as the quality of made tea, resistance to drought, pests and diseases. Molecular characterization of the evaluated estate cultivars showed a different clustering pattern as compared to the grouping pattern resulting from floral characterization. This indicated that molecular characterization does not reflect the sub-species level variation of the tea germplasm.
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.

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