PURSE 1998

Permanent URI for this collectionhttps://ir.lib.pdn.ac.lk/handle/20.500.14444/45

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Victims of political violence in the Hambantota District: a case study of Angunakola Palassa
(University of Peradeniya, 1998-11-07) Samaranayake, G.
Political violence has been a vital issue in the body politics of Sri Lanka since the early 1970s. There have been two patterns of political violence one involving the Sinhalease youth and the other Tamil youth. The first is the left-wing political violence with a view to establishing an egalitarian society of the socialist time. The second is the Tamil ethnic insurgency with a view to establishing a separate Tamil estate popularity known as the 'Eelam' state, comprising of the Northern and Eastern Province of Sri Lanka. A noteworthy feature of these two patterns of political violence is that civilience have become the targets of the strategy of both political violence and counter- violence by the government to crush the former. As a result, causalities or victims among civilience are higher than members of the armed groups and government force. Although much has been written on such violence, there is dearth of series writing probing into the causes of such violence. For example, there is no systematic study of the impact of political violence on civilience in the country apart from monitoring the result and displacement and migration of people.
Treatment of industrial effluents by natural susbstances.
(University of Peradeniya, 1998-11-07) Priyantha, Namal
Rapid growth of industrialization has caused serious environmental problems resulting in contamination of water resources with organic and inorganic pollutants. Consequently, increase in the levels of pollution parameters, such as suspended matter, chemical oxygen demand (COD), biological oxygen demand (BOD), heavy metals, nitrates and phosphates, would result in. Effective treatment of industrial effluent which would decrease these levels below the tolerance limits would therefore be of great importance. It is desirable that treatment methods be economical and environmentally friendly, to be practiced in developing countries. Naturally available substances such as dolomite, different types of clay (burnt brick, ball-clay, kaolinite, etc.), saw-dust, feldspar and laterite have become attractive in this regard. Treatment of laboratory prepared solutions, with added pollutants with the above stated natural substances, in beakers (static condition) indicates that ions of many heavy metals (chromium, manganese, iron, cobalt, copper, zinc, cadmium and lead) can effectively be removed by clay-based substances, feldspar, laterite and saw-dust. More importantly, some of these metals are removed to undetectable levels by some substances. Phosphates and sulfates are removed by dolomite and feldspar, respectively. Chemical Oxygen Demand (COD) is also decreased significantly by many of these substances. Efficiency of removal can be maintained at levels similar to those determined under static condition, when laboratory prepared samples are passed through glass columns packed with each substance (dynamic condition). Extension of this technology for treatment of effluents collected at brewery, ceramic, soft-drink and garment industries produces satisfactory results. However, the efficiency of removal of many pollutants is less as compared to laboratory prepared solutions due to interference problems. Improvement of the efficiency of the treatment process by employing mixtures of substances packed in filters will be the next logical step of this research.
Technologies for global information infrastructure
(University of Peradeniya, 1998-11-07) Muthukkumarasamy, V.
The building of Information Infrastructure is almost changing the mission of communication engineering. The world needs better ways of finding and sharing information. The information that people want has not readily available online and low- cost multimedia communication has been available only in rudimentary forms. Differences between telecommunication networks and computer networks are being marginalised. Many activities have been directed towards achieving Global Information Infrastructure (011) and National Information Infrastructure (NIl) based on the consensus reached. As the demand for new applications, which require very high speed data transfer mechanism and large scale integrated networks, increases dramatically the performance of conventional equipment, network architecture and the telecommunication network management techniques need to be critically evaluated. The objective of this article is to examine the wide range of networking technologies available and to compare their performances using different performance measures. The scope of technologies include Ethernet, Frame Relay, xDSL, Gigabit Ethernet, ATM Cell Relay / B-ISDN. Variety of networks using transmission media ranging from dial-up lines, leased lines, microwave links, optical fibre, and wireless mobile links are considered. The study highlights issues such as interoperability, quality of service (QoS), reliability, BER, guaranteed QoS of different technologies and their application support for real time and non-real time systems including standard datacom services, multimedia communication, MPE02 live video, super high definition image systems and voice over IP. Due to continuous advancement in technologies, fast growing demand for wide ranging new services, all confusing claims by competitive marketing personal for their products and changing attitudes of the telecommunity world over, it becomes difficult for the netrnanagers to decide what to order and what to expect. They not only have to evaluate the performance and suitability of the various available technologies for their current needs but also have to forecast almost imaginatively the possible future trends in OIl and NIl for their strategic planning and deployment of information infrastructure.
Verrucous carcinoma in the oral cavity
(University of Peradeniya, 1998-11-07) Baheerathan, N. N.; Mendis, B. R. R.; Amemiya, A.
The verrucous carcinoma (VC) is a distinct variant of squamous cell carcinoma. It has low grade malignancy, slow growth and low metastatic potential. VC is chiefly exophytic. However VC can invade and destroy oral tissues including bone. Although it has been reported in other sites such as larynx and genitalia, the tumour is most frequently found in the oral cavity. As VC runs a relatively benign course, it could be effectively treated surgically and is prognostically favourable. Thirty-eighty cases ofVC of the oral cavity were reviewed for their clinical and histopathological characteristics. Data for this study was gathered from specimens available at the Department of Pathology at the Faculty of Dental Sciences from 1978 to 1998. All biopsies diagnosed histopathologically as VC was reviewed by using the histologic criteria defined by Ackerman in 1948. The criteria are: 1) Papillary or verrucous projections on the surface 2) No connective tissue invasion at the basement membrane zone 3) Mild or no dysplasia of the epithelium 4) Parakeratin or orthokeratin plugging on the surface 5) A broad and advancing front of the lesion into the subjacent connective tissue and 6) A chronic inflammatory cell infiltrate in the connective tissue, mainly lymphocytes and plasma cells. The cases which did not meet the above histopathologic criteria were eliminated.Clinical data were collected from the submitted biopsy request forms. The tumour occurred chiefly in older patients ( age range from 15 to 76 years,mean age 54.3) and more often in males than in females (32 males- 84.2% and 5 females-13.15%) The sex of one patient (2.65%)was not available. The site of lesion was known only in 19 patients. The most common site of occurrence was the buccal mucosa (10 cases). Macroscopic appearance of lesion was reported as either exophytic or warty and white. All the cases showed marked epithelial thickening with series of irregular papillary projections .All the biopsies showed broad rete ridges .These rete ridges showed no evidence of invasion at the connective tissue interface and basement membrane was intact.71.1% (27) of the cases showed no epithelial dysplasia and 28.9% (II) of biopsies showed mild epithelial dysplasia .Moderate to intense inflammatory cells infiltration was present in 84.2% (32)of cases, predominantly lymphocytes.Less intense inflammatory cells present in 15.8%(6) of cases.In 94.8%(36) of the cases,keratin plugging was present but the absence of keratin plugging did not exclude our diagnosis of VC
A survey of calf management practices among farmers in mid-country dairy production system
(University of Peradeniya, 1998-11-07) Abeygunawardena, I. S.
Calf management stands out to be one of the key determinants of success of dairy fanning. Calf survival, prepubertal growth, postpartum fertility and total milk available for sale and hence the profitability of the farm operation very much depends on the method of suckling of calves that the fanner adopts in the farm. A field survey, therefore was conducted to determine the prevalent calf suckling management practices among fanners in mid-country dairy production system as a prelude to a long term investigation into the effects of various calf rearing methods on the above aspects. Two hundred smallholder farms were selected randomly and a field survey was conducted using a structured questionnaire to collect data on calf management practices. Results of the study have shown that 53.0% and 46.5% farmers practiced intensive and semi- intensive management systems, respectively. Extensive management was practiced by 1.5% of the fanners. Almost all the fanners were aware of the value of colostrum feeding. Limited suckling by calves was practiced by 96.4% farmers while zero suckling was practiced by 2.0% of the fanners. The remainder (1.6%) practiced ad- libitum suckling. Within the limited sucking group, 17.0% and 83.0% of calves were allowed to suckle the mothers once and twice a day, respectively. Within this group further differences were found as regard to the method of suckling. Fifty one percent of the fanners left milk in one full quarter for the calf and milked the other three quarters completely while 49.0% farmers milked all four quarters and left the residual milk for the calf. There were also differences as regard to time of suckling; 44.2% allowed both pre-and post-milking suckling and 53.8% allowed only post-milking suckling. the remainder (2.0%) practiced only pre-milking suckling. The average age at weaning was 26.2+ 12.62 weeks.
Surface sensitive v-shaped switching in chiral smectic liquid crystals.
(University of Peradeniya, 1998-11-07) Chandani Perera, A. D. L.
Antiferroelectricity in chiral smectic liquid crystals shows tristable switching, which is the electric-field-induced transition between antiferroelectric (AF) and ferroelectric (F) phases and has characteristic DC threshold and hysteresis. Although antiferroelectric liquid crystals has some display characteristics superior to ferroelectric liquid crystals, the pretransitional effect in the electric-field-induced AF-F phase transition, which appears as a slight increase in the transmittance below the threshold prevents antiferroelectric liquid crystal displays from achieving much higher contrast. During the development of materials to suppress this pretransitional behaviour, liquid crystalline materials showing thresholdless, hysteresis-free, V-shaped switching have been discovered. This V -shaped switching has attractive display characteristics such as wide viewing angle with high contrast ratio, fast response to applied field etc. suggesting potential for active matrix or thin film addressing in display devices. This paper presents a study of the influence of the alignment layer coated on the substrate on the V -shaped switching. The liquid crystalline material 4-[(1- trifluoromethyl- 5 - ethoxy) phenyloxycarbonyl- 3 - fluoro] phenyI4'-(n-undecyloxy) biphenyl- 4 -carboxylate used has the following phase sequence. Isotropic (82 oc) Sm A (81 oc) Sm X* This material shows V -shaped switching in the phase denoted by Sm X'" in thin homogeneous cells. Several polyimides with different chemical structures were used as the alignment layer. In this study, we investigated the influence of the alignment layer on the V -shaped switching by measuring the optical transmittance of the liquid crystal cells made with various alignment layers, under crossed nicols while applying a triangular wave voltage at various frequencies and temperatures. One side rubbed thin homogeneous cells were prepared. The polarization switching current peaks were also observed in the same cells by applying a 1 Hz triangular wave voltage. In order to confirm the surface sensitiveness of V -shaped switching, typical ferroelectric and antiferroelectric liquid crystalline materials were used and carried out similar measurements. It was found that this V -shaped switching strongly depends on the thickness of the alignment layer coated on the substrate surface. Thick alignment layers give rise to ideal V-shaped switching while thin layers change V -shaped switching to W-shaped switching. Further, it was found that typical ferroelectric and antiferroelectric switching unlike V -shaped switching have essentially no dependence on the thickness of the alignment layer. Very broad switching current peaks were observed for V-shaped switching which is quite different from the shape of the typical switching current peaks of ferroelectric/antiferroelectric liquid crystals. This broad switching current peak would be a characteristic feature of V-shaped switching.
Suppurative inflammation in the soles of the feet (Pododermatitis)of Sri Lankan elephants(elephas maximus, maximus, linnaeus, 1758) and the Causative Bacteria
(University of Peradeniya, 1998-11-07) Gamage, C. N. S. G.; Kuruwita, V. Y.; Dangolla, A.
Pododermatitis is a serious health problem in captive elephants in Sri Lanka (Elephas maximus maximum; Linnaeus, 1758) requiring intensive treatment for months or even years, and if neglected could lead to death. The objective of this study was to identify species of organisms (aerobes) involved in causing Pododermatitis in elephants to ascertain any relationship between cracks and severity of the disease. Hind legs of fifty five elephants were examined and, were categorised into groups according to the number of cracks on soles (low 1-5 cracks, medium 6-10 cracks and high 10 or more). Severity of the Pododermatitis was determined by the presence or absence of the exudate associated with the inflammation. The age groups studied were sub adults of 10-20 years, prime adults of 20-40 years and senior adults of more than 40 years. The studied population consisted of 23 males and 32 females. Thirty five (35) of the animals were senior adults, 19 were prime adults and only one was a sub adult. Thirty five (35) animals (62%) had Pododermatitis at least in one of the soles. Fifteen animals had lesions in both hind legs, eight in right hind leg and 9 in left hind leg. The numbers of elephants who had low, medium and high numbers of cracks were 14, 33 and 3 respectively. Eight(8), 21 and 3 animals of the above respective groups had lesions of Pododermatitis. The degree of Pododermatitis was severe in 18 of the above animals and especially in the 3 animals with high numbers of cracks. Streptococcus, Staphylococcus (s. Aureus), Klebsiella, Proteus, Corynebacterium and Escherichia coli species were identified from cultured pus samples obtained from the lesions. Severely overgrown soles with cracks require frequent foot trimming for recovery. Sanitation of the stable and frequent evacuation of urine and dung is necessary. Foot baths of 5% formalin can be used to harden the sole. It has been shown that a balanced diet could prevent this problem. Antibiotics are used to prevent septicaemia and to inhibit the rapid growth of bacteria which may occur as a secondary reaction to Pododermatitis.
A study on patients discharged from medical ward, Teaching Hospital, Peradeniya
(University of Peradeniya, 1998-11-07) Nugegoda, D. B.
A 15% random samples (355) of discharged patients from the medical ward were interviewed by medical officers using a questionnaire. Response rate was 100%. Thirty nine percent had by-passed their closest hospitals. Main reason for by-passing were lack offaith in local hospitals (50%) and no effect with treatment from local hospitals (33%). At discharge a third of the patients did not know the disease they had, while 42% did not know the cause/s for the disease, 28% did not know the after care. Almost half of the patients, said that they did not receive any education on their illness. Ninety three percent of the patients felt that hospitalization had cured! controlled their illness. Satisfaction of the patients regarding various aspects were as follows: adequately investigated 82%, adequately examined 87%, received drugs on time 94%, consultants care 95%, house officers care 99%, nurses care 99%, attendants care 97%. Ninety one percent found wards clean, 64% found the toilets clean. Only 48% had a bed during entire hospital stay. Fifty two percent did not consume hospital meals. Among the 48% who took hospital meals, satisfaction on various aspects were as follows: quantity 99%, taste 52%, cleanliness 89%, serving 92%, time served 94%. Ninety two percent of the patients said that they did not have any unpleasant experiences during their hospital stay. Overall patients seem to be happy with the hospital services and care. However, more effort should be taken to educate patients on their diseases and after care.
Study of total protein concentration, pH and salivary flow rate in the whole saliva collected from patients with rapidly progressive periodontitis( RPP)
(University of Peradeniya, Peradeniya, 1998-11-07) Ruwanpura, S. M. P. M.; Wimalasiri, W. R.; Chandrasekera, A.
Periodontitis is the clinical state produced due to the interaction between the microbial dental plaque and human host defenses. It is established that periodontitis is modulated by complex interactions between plaque bacteria and host immune - inflammation defense mechanisms. The products of the interactions are released through periodontal tissue and crevicular fluid to saliva. Therefore saliva could be used as a good diagnostic tool to diagnose various types of periodontitis in the very early stages of the disease. Moderate to Severe Adult Periodontitis (MSAP) and Rapidly Progressive Periodontitis (RPP) are two important types of periodontitis. MSAP is highly prevalent and less destructive and RPP, which is a type of early onset periodontitis, is less prevalent and highly destructive in nature. It is important to diagnose the type of periodontitis, as the treatment planning is different from one type to the other. It is also emphasized that early diagnosis is of paramount importance to avoid edentulousness in young age. The salivary constituents could be used to diagnose types of periodontitis. This study is a preliminary attempt to compare the salivary constituents of subjects with apparently healthy periodontium, MSAP and RPP. 30 subjects were studied. They were clinically diagnosed and divided into the healthy group, MSAP group and RPP groups, each group containing 10 subjects. Each group includes 6 females and 4 males. The age distribution ofRPP group was 25-29 Yrs. (4 subjects), 30-35 Yrs. (4 subjects) and 36-40 Yrs. (2 subjects). In the MSAP group it was 1 subject in the 25-29 Yr. group, 2 subjects in the 30-35 Yr. group, 4 subjects in the 36-40 Yr. group and 3 subjects in the 41-45Yr. group. In the healthy group we had 3 subjects each in the 25-29 Yr. group and the 36-40 Yr. group and 2 subjects each in the 30-35 Yr. group and the 41-45Yr. group. Unstimulated whole saliva from each individual was collected. The pH, total protein level (mg! L) and flow rate (mll Min.) was measured. The patients who are already being treated were not included in the study. According to the preliminary results, RPP patient's mean salivary flow rate was 0.43 mil Min. compared to the rate of the healthy group which was 0.55 mll Min. This is not statistically significant (p= 0.05.). Mean total protein in the RPP, MSAP and healthy groups were 5574 mg! L, 4068.8mg! Land 2643.5 mg! L respectively. This is statistically significant (p= 0.01). The mean pH of saliva of the diseased group was 6.8 and that of the healthy individuals was 7, a deferent that is statistically significant (p=O.OI).
A study of some of the factors affecting childhood obesity
(University of Peradeniya, 1998-11-07) Karunawansha, M. G. A. P. K.; Karunathilaka, R. L. L.; Kachchakaduge, B. L. K.; Kalansooriya, P. L. K.; Mihilar, M. M.; Sivakanesan, R.
The objective of this study was to identify factors associated with childhood obesity among a selected population of Sri Lankan children. One hundred and nineteen families (186 children below 12 years) were included in the study. Bio-data of the family members were obtained by interviewing. Weights were measured using a bathroom scale (sensitivity - 250g), height was measured using a simple device made for the study and the skin fold measurements were made with a Harpenden skin fold calliper. The weight expressed as a percentage of the reference weight to age and sex was considered as a measurement of obesity in children. Children whose weight exceeds 120% above the upper reference value were labelled obese. Reference weight were from the weight to age chart of the child health development record issued by the Family Health Bureau of the Ministry of Health and the weight to age and sex chart by Aponso (1991), for the age groups of 0 - 60 months and 5-12 years respectively. Multiple correlation analyses were used to assess the correlation between weight expressed as a percentage of reference weight and certain other variables which were treated as continuous. Secondly student's t - test was used to compare the mean values of some factors of obese and non obese children. Maternal body mass index (P< 0.01), maternal weight (p<0.0001), maternal biceps (P< 0.01), maternal triceps (P<0.0001), paternal weight (P<0.01), and paternal biceps (P<0.05) were positively correlated with childhood obesity. The weight of the children (as a percentage of the reference) correlated negatively with family size and intake of rice, and positively with intake of meat. It also tend to increase with the increasing maternal educationaIlevel. The only useful factor that was highly correlated with measures of childhood obesity was parental weight. In families with either one or both parents are obese, emphasis should be placed in the adoption of measures to prevent the development of obesity in children. References Aponso.H.A. (1991). Weight charts of children. Your child and your family.
Study of internal browning and some associated physico-chemical and biochemical parameters in two pineapple cultivars during cold storage
(University of Peradeniya, 1998-11-07) Weerahewa, Darshani; Dharmasiri, Sunethra
Internal browning is a physiological disorder, commonly encountered in pineapples during prolonged cold storage under low temperature (8-15 c). 'Mauritius', the most popular dessert cultivar is more susceptible to internal browning. This condition prevents sea-freight transportation of local pineapple to the distant markets of the world forcing the exporters to air-freight pineapple which results in increased transport cost and reduction in export volume. The characteristic symptom is the development of translucent areas on the tissue adjacent to the core areas which subsequently spread into the core. The affected areas enlarge and turn brown as severity of the condition increases. Typical internal browning symptoms are often exhibited by the cultivar 'Mauritius' and in the cultivar 'Kew' the symptoms are confined only to isolated patches of tissues adjacent to the core region. Pineapple cultivar 'Mauritius' show internal browning symptoms within 10 days of cold storage at 10 C whereas in the cultivar 'Kew' the symptoms appear 14 days after cold storage. Storage of fruits of cultivar 'Mauritius' packed in polythene bags under vacuum low temperature delayed the symptom appearance compared to the fruits stored without polythene bags. But such a difference was not observed in the cultivar 'Kew'. The internal browning results from a combination of both cellular damage and brown pigmentation due to the phenolic metabolism. The enzymes, phenyl alanin ammonia-lyase (PAL), polyphenol oxidase (PPO), and peroxidases (POD) are known to be involved in the synthesis of phenols and hence in the development of internal browning disorder. Activity of these enzymes was assayed using acetone powder prepared from tissues removed from areas around the core region of pineapples 7,lO,14,18,and 21 days after cold storage. It was found that the two enzymes, PPO and POD, were associated with the development of internal browning in both varieties, however the activities of these enzymes were higher in cultivar 'Mauritius' than in 'Kew.' PAL activity of fruits belonging to both cultivars was similar when they were Both 'Mauritius' and 'Kew' fruits cold stored under normal and modified atmosphere, showed similar phenylalanin ammonia lyase activity (PAL) at all stages. The fruits stored at modified atmospheric conditions (polythene bags under vacuum) showed contrast in POD and PPO enzyme activities. The varieties 'Mauritus' and 'Kew' stored under MA conditions showed higher values of enzyme activities compared to the fruits stored under normal atmospheric conditions.But PAL activity was similar in two varieties in both conditions. The % titratable acidity was higher in vatriety 'Maurtius', than the variety 'Kew' during the days of cold storage.
Stresses in Stupas of different shapes
(University of Peradeniya, 1998-11-07) Ranaweera, M. P.
Stupa, the most notable feature of almost every Buddhist temple in Sri Lanka, is found in many sizes and shapes. Jetavana stupa, considered the tallest brick structure in the world, is said to have been 122 metres (400 feet) tall and it has a dome in the shape of a paddy-heap. Sri Lankan stupas have domes of many shapes. Traditional domes are bell shaped (ghantakara), bubble shaped (bubbulakara), pot shaped (ghatakara), paddy- heap shaped (dhanyakara), lotus shaped (padmakara), and nelli-fruit shaped (amalakara). Of these bell shape is the most common and the largest stupas are of paddy-heap shape. Some stupas have changed in size and shape during re-constructions and restorations. Of these shapes some are more stable than others, and the ancient stupa builders would have arrived at the most stable shape for the required height by trial-and-error processes, rather than by mathematical analyses. However recent restoration and conservation work of ancient stupas has necessitated studies of stress analysis, as some ill-prepared restorations had resulted in disastrous consequences. This paper presents some results of a study of stresses in the domes of the four most common shapes of stupas, taking as examples Mahiyangana stupa (bell shape), Mirisaveti stupa (bubble shape), Jetavana stupa (paddy-heap shape), and Tissamaharama stupa (pot shape). The stresses in their domes due to self weight loading were computed by finite element analyses using the SAP90 general purpose package, and treating the problems as axisymmetric ones. Vertical, radial, circumferential, and shear stress contours, as well as displacements were obtained for each stupa, and some comparisons were made after normalizations. The results show that most parts of the domes are in compression with the maximum compressive stresses well below the compressive strength of ancient bricks. Tensile zones are present in some of the domes, with the pot shaped dome having the largest tensile zone and the maximum tensile stress. The latter is also well below the tensile strength of ancient bricks.
Strategic feeding and feed resources for sustainable milk production
(1998-11-07) Perera, A. N. F.; Perera, E. R. K.
Feeding system and nutrition are two major determinant factors of sustainable milk production. Ruminants are unlike monogastric livestock, they require feeding round the clock, due to its anatomical and physiological nature of the highly specialized digestive tract. Nutritional requirement of the cow is mainly obtained from roughage based feeds and about 80% of the digestion is microbial based. In feeding ruminants one have to consider not only the requirements of the animal but also the microbes that assist the digestion. The availability of feed for ruminants is another limitation in present day dairy production. Considering the cost involved and the land pressure, cultivation of forages in the limited land area of the resource poor dairy farmer is unrealistic. Therefore, crop residues and agro industrial by products with other non conventional feed stuffs should be able to satisfy the bulk requirement of the animal. Rice straw is one of the major feed source extensively available but rice straw alone cannot provide required nutrients, due to low bio availability and digestibility. Sugarcane by products also available extensively along with other cereal and pulse straws. However, not even 15% of these crop residues are properly used in feeding dairy livestock. In addition, enormous quantities of other non conventional feeds are also available in the country. India the worlds largest milk producer, more than 80% of the nutritional requirements of their dairy animals are obtained through crop residues and agro industrial by products. Quality of these by products can be elevated by supplementation. Digestibility of straw can be increased from 28% to 52% by supplementation alone. Generally, supplements are expensive and high in demand. Tree fodder playa vital role in utilizing the roughage by elevating the digestibility and inducing a substitutional effect. This can be easily and economically obtained. Urea molasses mineral block (UMMB) is the latest feed supplement introduced to the Sri Lankan dairy animals and presently it is satisfactorily used. This UMMB has a dual effect; as a catalyst by improving the rumen conditions for rumen microbes for efficient roughage digestion and as a supplement to satisfy the deficient nutrients in the basal roughage. UMMB is easy to use and the cost is about 30% of the traditional supplements for similar performances. Presently using different feeding strategies and appropriate supplements, local dairy farmers realized the importance of economical and sustainable. milk production.
Sequestration of lichen compounds by the Butterfly talicadia Nyseus Nyseus
(University of Peradeniya, 1998-11-07) Bombuwala, K.; Karunaratne, V.; Ranawana, K. B.; Weerasooriya, A.; Wijesundara, S.; De Silva, E. D.
Lichens comprise about 20,000 species and are distributed throughout the world commonly growing on rocks and poorly developed soils such as arid lands and boreal- Arctic regions or as epiphytes on trees. In habitats which are poor in nutrients and subject to extreme environmental conditions (such as hot or cold deserts), lichens may form the dominant flora and thus provide important potential resources for herbivores. In spite of the toxic and deterrent effects of such lichen substances toward generalist herbivores, there are examples of specialised lichen feeders, such as orbit mites terrestrial gastropods and Lepidopterra, for example, family Arctiidae. In the present study we report, for the first time, occurrence of lichen substances in a butterfly identified as Talicadia nyseus nyseus (Guer) (red pierrot) which is closely associated with a crustaceous lichen growing on a roadside rock at the Beragala junction on the Badulla- Colombo road. Twelve adult butterflies of Talicadia nyseus nyseus who were found in close proximity to the lichen B802 (herbarium specimen number) were collected near Beragala junction. Twelve pupae which were suspected to be belonging to Talicadia nyseus nyseus were also collected from the lichen surface at same location. Butterflies were extracted into CH2CIz at room temperature. The dried lichen B802 (herbarium specimen maintained in the Department of Chemistry) was also extracted into CH2CI2 at room temperature. The CH2CIz extracts of both butterfly and lichen were subjected to thin layer chromatographic analysis (TLC). Adult Talicadia nyseus nyseus that emerged from the pupae were also extracted into CH2Ch and subjected TLC analysis, as before. The dichloromethane extract of the lichen BE/02 showed six clear spots upon (eluent dichloromethane) TLC. Three spots were identified as usnic acid, atranonin and ~-sitosterol, by co-TLC with authentic samples. Upon comparison, the dichloromethane extract of Talicadia nyseus nyseus exhibited four of the six compounds which the lichen contained namely f)-sitosterol, atranonin and two other as yet unidentified compounds. The presence of the lichen substances such as atranonin and f3-sitosterol in adult Talicadia nyseus nyseus indicate that their larvae feed on the lichen B802. Although larvae of moths (Arctiidae) are known to be lichen feeders, to the best of our knowledge, there arc no previous reports of the butterfly family (Lycaenidae) feeding on lichens. Talicadia nyseus nyseus usually feeds on crassulaceous plants such as Bryophyllum calcinum. Financial Assistance from NSF (RO/96/C/04) is acknowledged.
Solid state electrochemical cells based on Peo-Mg(CIO4)2 polymer electrolyte and Mg/Cu electrodes
(University of Peradeniya, 1998-11-07) Bandara, L. R. A. K.; Dissanayake, M. A. K. L.; Careem, M. A.; Amaleswaran, R.
Polymer electrolytes have been of great interest partially due to its possible application in advanced high-energy electrochemical devices, i.e., batteries/fuel cells, electrochromic display devices/smart windows, photo-electrochemical solar cells, etc. Many of the solid state electrochemical cells that are being used or being developed at present are based on u: ion conductors which are more expensive and less stable. Magnesium ion conducting solid polymer electrolytes have the advantage of low cost and the cells based on these electrolytes have the possibility of using magnesium metal as an electrode material. It is, therefore, interesting to study characteristics of Mg+2 ion based solid state cells. In this work, we report the results of studies on various polymer electrolyte films developed based on PEO complexed with Mg(Cl04h salt with the plasticizer, ethylene carbonate (EC). Polymer electrolyte films have been prepared by solvent-cast method. DC polarization technique and Differential Scanning Calorimetry (DSC) have been employed for studying the complexation of the salts with the polymer and the plasticizer. The AC conductivity measurements have been made in these plasticized polymer electrolyte systems in the temperature range from 25 to 110°C. The conductivity of the system with maximum conductivity was found to vary from 10-4to 10.3 ohm'! cm-! within the above temperature range and the maximum conductivity of 6.43x 10-4S cm-! at room temperature was found for the sample with composition Mg(Cl04h[0.5PEO + 0.5EC]10·The transference number suggests that the charge transport in these polymer electrolyte systems is mainly due to ions, with a negligible contribution from electronic. The conductivity vs temperature behavior is found to be of VTF type for all the complexes studied over the entire temperature range. The amorphous nature of the studied system was further confirmed by the DSC results. Solid state electrochemical cells have been assembled by using the above electrolyte film as the electrolyte and Cu and Mg as electrodes. The performance of these polymer based solid electrochemical cells have been studied by the discharge characteristics at different loads. The open circuit voltage (Voc) and the short circuit current (lsc) for the cell configuration Mg/Mg(CI04MO.5PEO + 0.5EC]lO/CUwere found to be 1.36 V and 1.63 mA respectively. The capacity of the cell was found to be 3.01 mAh.
Sensorless control of permanent-magnet synchronous motors for improved performance
(University of Peradeniya, 1998-11-07) Alahakoon, S.; Walgama, K.; Leksell, M.; Harnefors, L.
Energy efficiency, low acoustic and electromagnetic noise emISSIOn are becoming prime demands for commercial AC drives. The solution for this is to employ more and more controlled motor drives rather than using DC or induction motors that operate open loop. Even though the industries in North America and Europe have been developing their products to meet those demands, the tendency of using efficient variable speed AC drives in domestic and industrial environment is not at a satisfactory level in developing countries like Sri Lanka. Availability of efficient and fast switched voltage supplies (inverters) and powerful digital signal processing devices (micro-controllers, Digital Signal Processors (DSP), etc.) has enabled the design engineers to produce variable speed AC drives with feedback control loops for either speed or angular position. The invention of Permanent Magnet Synchronous Machines (PMSM) has now emerged as a challenging alternative to the conventional Induction Machine (1M). In recent years there has been significant development and attention for the control of PMSMs of various types. There are definite advantages of PMSMs over IMs due to their high efficiency, high torque to current ratio, high power density and low inertia. Conventional PMSM drives employ a shaft mounted encoder or a resolver to identify the rotor flux position. This maintains the synchronism that is an essential requirement in drive control. But on the other hand, in most applications the presence of an encoder or resolver causes several disadvantages due to additional cabling cost, a higher number of connections between motor and controller, noise interference and reduced robustness. This arises the need to develop sensorless (i.e. measurement is replaced by estimation) control schemes for PMSM drive systems. We can basically identify two categories of position (and speed) estimation methods proposed so far. One is the extraction of position information available in the back emf. The other method is the injection of a high-frequency sinusoidal voltage or some other disturbance in order to detect the saliency of the rotor. The aim of this paper is to introduce a new position (and speed) estimation method using the back emf technique. It also presents some results obtained in dealing with periodic disturbances occurred during real-time implementation of the above method. Authors would like to pay thair gratitude to the funding organisation on SIDA Sweeden for financing the project.
Self-Medication in a defined community in Sri Lanka
(University of Peradeniya, 1998-11-07) Wijeratne, P. D. P.; Paranathala, D. M. L. B.
To findout the extent and practice of self-medication in a defined community and compare the results with a control group. (Medical students) A randomly selected 144 subjects aged> 18 years in the MOH area Hindagala and 100 first year medical students (95/96) formed the study subjects. Data was collected using a pre- printed questionnaire from August to December 1997 and the results analysed statistically. 112 completed questionnaires received from the community. The prevalence of self-medication in the community (77.68% n=87/112) was lower than that in the student population (p < 0.001). In the community, self-medication was associated with literacy and there was a tendency to self-medicate both 'over-the-counter' and 'prescription only' drugs; 60.9% (n=53) self-medicated 1 to 5 times frequency in the previous 6 months, "Good past experience" was the main reason for their self-medication. 89.65% (n=78) in the community expressed satisfaction with their self-medication. None in either population stated any untoward effects of their self-medication. This study reveals that a significant percentage of subjects in the community indulge in self-medication practice. Furthermore it was associated with literacy, the educated beingpracticing more (P < 0.05). The self-medication of 'prescription only drugs' in the community as in the student population is a cause for concern. According to this study self-medication appears to have been practiced without untoward effects that merit mention.
Role of grandparents in Sri Lanka: a pilot study
(University of Peradeniya, 1998-11-07) Wikramanayake, Eugene
In the human species women lose their fertility after menopause around fifty years of age. Although men continue to produce germ cells till late in life, due to social constraints it is rare for a man too, to father a child after fifty years. The increasing life expectancyespecially of the women has led anthropologists to speculate whether there was a selective advantage in having grandmothers around even in the stone age with a hunter gatherer life style. The hypothesis is that the older women did the gathering while the men did the hunting. The younger women bore children and looked after them. However the life expectancy of both sexes keeps on increasing even though life styles have changed dramatically.Human young when compared to those of other mammals have to go through a prolonged maturation period of psychosocial development before they themselves can become parents. Most of this maturation involves learning. The hypothesis made in this studyis that having grandparents more mature than the younger parents may be of selective advantage in the human species in contributing towards the psychosocial development of the human young. A study was designed to elicit the role of grandparents in the maturation period form preschool through primary and secondary schooling in the 2nd year medical undergraduates at Peradeniya. A questionnaire to elicit the role of the four grandparents, maternaland paternal grandmothers and maternal and paternal grandfathers was prepared. Informationregarding the number of grandparents alive at the birth of the undergraduates, the number living at home and the number of years of association during the formative years was also elicited. Eighty three males and forty females entered the study. Eighty percent were from rural backgrounds and in 80% at least one parent was a teacher. Fifty percent of the mothers worked away from home. The average age of the undergraduates was 23 years with a range of 19-25 years. Eighty two percent of the maternal grandmothers, 69% of the paternal grandmothers, 62% of the maternal grandfathers and 56% of the paternal grandfathers were alive when the undergraduates were born. Of these 86% lived in the same house or close by. The average years of associationwas seven for the maternal grandmother, six for paternal grandmother, four for the maternal grandfather and three for the paternal grandfather. In general the grand parents contributed to a considerable extent in the "upbringing" of the undergraduates as reflected in the positive responses to the test item. The greatest involvement was by the maternal grandmother. The paternal grandmother and maternal grandfather in that order also contributed significantly. The least involved was the paternal grandfather. Definite involvement of grandparents in non-formal education and helping in caring for the grandchildren has been shown. More in depth studies are required to confirm that the increasing life expectancy of grandparents reflects a selective advantage in the socio-bilogical evolution of the human species.
School processes: a study of the taching-learning Processes within the classroom based on a selected sample drawn from the schools in the educational deistrict of Kandy.
(University of Peradeniya, 1998-11-07) Embakke, E. K. S. K.
This is an ethnographic study conducted to ascertain the quality and to evaluate the teaching -learning process in the schools. The research was conducted using eight schools, which represented different social class backgrounds in the Kandy District as research sites. In addition to the data obtained from observing the teaching-learning process in the classrooms, the researcher collected data from analyzing documents and by interviewing students and teachers as well. This enabled the researcher to triangulate and maintain the reliability and the validity of the data. The different stages of a classroom lesson namely planning, beginning, development and evaluation and feedback were continuously observed in the selected subject areas using various ethnographic research methods. The data thus collected and analyzed enabled the researcher to arrive at the following conclusions. 1. A majority of the teachers do not resort to yearly, termly, weekly or daily planning of their classroom lessons. Consequently the teaching-learning process is done without any prior planning. 2. The teachers do not care to plan their work because they are not subjected to any evaluation or supervision process. 3. Most of the teachers do not understand the significance of planning their classroom lessons. 4. The teachers in the schools attended by the lower socio-economic class children pay better attention prior preparation than those teachers in the superior schools in the urban areas. 5. Since the teachers do not resort to planning they are unable to motivate their students or to do any effective teaching. 6. In the daily teaching-learning process there is plenty of teacher talk which is carried on using only the blackboard and the textbook only. The result is a boring lesson. 7. Most of the teachers do not make any attempt to evaluate and ascertain whether the objectives of the lessons are achieved by using proper and suitable evaluation procedures. It is the opinion of a large number of them that evaluation and feedback unnecessary. The ultimate result is that half-baked knowledge is transmitted. The above conclusions clearly indicate the realistic picture of what is happening in our classrooms. The eradicate the weaknesses and the drawbacks in the existing systems, various remedial measures have been suggested by the researcher. Among these suggestions the significant ones are, that a close monitoring of teacher activities in the classrooms are essential in addition to the step that should be undertaken to educate the teachers of the teaching methodologies that could be adopted in our classrooms. It is also suggested that various teacher education institutions should be given the opportunity to get involved in the implementation of such programs. The researcher sincerely hopes that this study would lead to the improvement in the quality of the teaching-learning process and that the future researchers would study as to how these suggested programs could be successfully implemented so as to maintain the quality of the teaching-learning process in our schools.
Provenance variation in condensed tannin content of calliandra calothyrsus
(University of Peradeniya, 1998-11-07) Premaratne, Sujatha.; Perera, H. G. D.
A field experiment was conducted with fifteen provenances to evaluate the provenance variation in condensed tannin content of fresh leaves of Calliandra calothyrsus. Experimental design consisted of line planting on double hedge rows (3m long plot, 112 meter interval, 45 plants in each plot) with 5 replicates. Plants were lopped every 5 months and samples (10 different plants within a plot; 4 newly flushed leaves, 4 partially expanded leaves and 4 mature full expanded leaves from each of 10 trees in a plot) were collected and kept on ice before transferred to the laboratory. The proanthocyanidine were extracted in aqueous acetone and total extractable proanthocyanidine (TEPA) and total proanthocyanidine (TOP A) were measured by the standard method. TEPA content ranged from 11.22 (Georgesville - Belize) to 16.01 (Patulul - Gautamala) (measured as absorbance at 550 nm.g" OM) whereas local provenance had a lower TEPA content (11.91 as absorbance at 550 nm gotDM). TOPA content ranged from 24.57 (Georgesville - BeUise) to 31.72 (Santa Marie de Jesus - Gautamala) (measured as absorbance at 550 nm, got OM).TOPA content of the local provenance was higher compared to some of the imported provenances. Based on the nutitive value, provenances, such as Georgesville (Belize), local, Coban (Gautamala), Patulul (Gautamala) and Bombana (Mexico) can be selected.

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