PURSE 1998

Permanent URI for this collection

https://ir.lib.pdn.ac.lk/handle/20.500.14444/45

Browse

Now showing 1 - 20 of 118

A case of juvenile active or aggressive ossifying fibroma(JAOF) in relation to the maxilla
(University of Peradeniya, 1998-11-07) Prabaharan, P. J.; Mendis, B. R. R. N.; Attygalla, A. M.
In the view of many pathologists and surgeons, the group of fibro-osseous lesions (FOL) occur by the replacement of the normal bone by fibrous tissue. Thereafter there is the formation of a new form of calcifying mass by the process of mataplasia. The FOL comprise of a diverse, interesting and challenging group of lesions that pose difficulty in classification and management. The FOL of the jaws may vary from asymptomatic lesions discovered by accident in routine radiographs to extensive, cosmetically and functionally disturbing lesions. Proper diagnosis of these lesions depend on a good correlation of the history, clinical findings, radiographic characteristics, and the histopathological appearances. Microscopically the lesion consists plump osteoblast like cells, surrounding areas of osteoid. The patient is a 18 years old male, from Vavuniya. He first reported to the Kandy General Hospital (Centre for sight), with a gradually progressing right sided proptosis and swelling in relation to the right eye. He had no pain but reduced vision on the right eye. He later reported to the Dental Hospital, Peradeniya with the same symptoms and an initial diagnosis of fibrous-dysplasia of bone was made. Further investigations such as like C.T Scans and histopathological observations reveals the diagnosis of Juvenile Active or Aggressive Ossifying Fibroma. Discussion A. JAOF is most often seen in the maxilla and the patients are in the first or second decade of life. This tumour is more cellular than any other fibro-osseous lesion. Some of these cells produce streams of osteoid that may bear some resemblance to the osteogenic sarcoma. B. According to the Johnson (1967) these lesions are aggressive and extend into antrum and approach the nasal septum and medial wall of the obit, causing proptosis and exopthalamos. Some of these lesions become osteogenic sarcomas while others mature into ossifying fibromas. JAOF may have an ancestral relationship to osteoblastoma because of the overlapping histological features of both lesions. Reed and Hagy (1965) also consider the JAOF and osteoblastoma to be the identical lesion.
A case of recurrent Central Giant Cell Granuloma in relation of the Maxilla
(University of Peradeniya, 1998-11-07) Attygalla, A. M.; Amaratunge, N. A. De S.; Mendis, A. R. R. N.
Central giant cell granuloma ( CGCG) of the jaws is an uncommon lesion which accounts for less than 7 percent of all benign lesions of the jaws. The CGCG is defined by the WHO as 'an intra osseous lesion consisting of a more or less cellular fibrous tissue containing multiple foci of haemorrhage, focal aggregations of multinuclear giant cells, and sometimes trabeculae of woven bone formation within the septa of more mature fibrous tissue that may traverse the lesion. The aetiology of the CGCG is unknown and its biological behaviour is poorly understood. In 1953, Jaffe identified these lesions as "giant cell reparative granulomas" to distinguish them from the giant cell turnours that are usually found in the epiphysial regions of the long bones. There are reports in the literature of CGCG behaving as slow growing neoplasms. The features of such lesions are gross bone destruction, displacement of teeth, enveloping and often erosion of roots, perforation of the cortex and also pathological fractures. A case of central giant cell granuloma of a 26-year-old Sinhalese woman is presented. The lesion was in relation to the left maxilla, involving the hard palate and extending from ~ crossing the midline. The occipitomental radiograph showed a mixed radiolucent lesion involving the left maxilla with ill-defined margins. The CT scan revealed a lobulated expanded lesion arising from the left maxilla which extends in to L nasal cavity, L maxillary and ethmoidal sinuses, L nasopharynx and infero medial aspect of L orbit. The management of this lesion and the difficulty of differentiating it from central giant cell tumour of bone are discussed. The comparisons of the CGCG and the Central Giant Cell tumour of Bone are given below. Detailed diagram is availble in the pdf
A design of solar energy crop dryer
(University of Peradeniya, 1998-11-07) Obeyesekara, B. R. K.; Elankathir, A.
This paper discusses how to improve the qualitative characteristics of cereals by utilizing the Solar Energy Ventilating systems. As the economy of the rural community of developing countries is mainly based on their agricultural crops, securing the quality of the product would be one of the main and essential aspect in agricultural industry. As harvest of the various crops is reaped in different time during the year, it requires the necessity to keep the crops for longer period of time without causing any damages to them. Damage can be caused by insects, fungal, thermal etc. High quality of agricultural crops such as cereals, make available to draw foreign currency in to the country in to the country and also crops will be marketed as high quality product by maintaining its moisture content, color shape, sizes and so on. In village community, the farmers who deal with cereals in small scale, finally sale to the whole sale dealers. At most of the time, the product itself shows poor quality subjected to different undefined techniques of drying. As a result of this most of the cereals end up with fungal attacks and discolour of products as they are exposed to the moisture environment and the direct sunlight. Hence the total quality of the cereals naturally falls down. Further the paper discusses the methodology to solve this problem. It is suggested to have a Solar collector system, hot air of which passes to a chamber in which the cereals are kept for further drying after initial drying of direct sun light. As the experimental study is new in this nature (crop drying) and it gives couple of recommendations and values of parameters of the geometrical configuration of the Solar Energy ventilator for different types of cereals. The temperature and the flow of hot air can be controlled by changing the geometry of the solar collector. Further the experimental study shows that serious limitations for the diameters of inlet and out let of solar collector ducts. This new mathematical models show how to control the flow and temperature of the air flow inorder to run with maximum gain more heat. A design of solar energy collector is now been constructed at the Nawa Nilambe Estate for drying of 1000 kg. of Pepper, Coffee, etc.
A low cost electronic solar rediation sensor
(University of Peradeniya, 1998-11-07) Alahakoon, P. M. K.
The two most important parameters which govern the environment are temperature and relative humidity. These, collectively alter the moisture content offood commodities. Therefore, continuous monitoring of relative humidity and temperature has become extremely important in many applications where food produce such as grains are stored under controlled environments. Relative humidity measurement is also a very important component in weather monitoring that rovides information on most favourable conditions for plant growth and optimum yield. The design and development of a new sensor for monitoring humidity of air was carried out. Upon considering the types of transducers and their characteristic features, it was decided to construct a new sensor, primarily based on the technique used in the hair hygrometer. This method was considered to be one of the most simple and versatile with respect to the transducer mechanism and possible application areas. A band of hair was obtained by attaching each strand to two supports. A low tension was maintained so that all the strands were uniformly stressed under tension. A fast drying glue (Super-Glue) was used to affix hair to the supports at both ends. The band of hair (length 27 em and approximately twenty four individual strands) thus prepared was used in this research to obtain the moisture dependent displacement. A piece of a high carbon steel hack-saw blade of length 5 em was used to transform the deflection caused by the hair band due to its common availability and good mechanical properties. In order to detect the mechanical deflection caused by the contracting and expanding band of hair, strain gauges were affixed to both sides at one end of this blade. A 30 em long,S em high L-shaped Poly Vinyl Chloride (PVC) frame was prepared and used as the supporting frame for the hair band and the steel blade. The sensor was calibrated and tested in the laboratory along with a standard wet and dry bulb type relative humidity measurement system. The moisture level was varied by using an air-conditioner output and adding heat and moisture to the flow stream as required. . The designed moisture sensor worked successfully providing a voltage output that varied linearly with the relative humidity of the surrounding environment. The device was inexpensive (total cost: Rs. 985.00) compared to the other devices available. The analog voltage output provided by the sensor was compatible with all automated data logging systems. The sensor could be used to measure relative humidity values with an accuracy of ± 2.3 %RH, and it was found to work successfully within the full range of relative humidity levels used during calibration (from 20% to 95% RH).
A mathematical model to predict groundwater contamination due to pesticide application
(University of Peradeniya, 1998-11-07) Kumaragamage, D
Mathematical models are often used to describe the transport of agro-chemicals in soils. Such models have been successfully used in many countries to predict the extent of groundwater contamination by various pesticides under certain soil and environmental conditions. The objective of this study was to formulate and validate a mathematical model to describe pesticide transport in soils, which can be used to predict the extent of groundwater contamination. The classical convective-dispersive transport equation was used considering irreversible removal of pesticide from solution due to adsorption and degradation. Preliminary experiments using carbofuran indicated that adsorption by soil particles is rapid and equilibrium was reached quickly, and that adsorption data in most soils fitted well to linear isotherm. Therefore, when formulating the model, a local equilibrium assumption with linear isotherm was used to characterize pesticide adsorption. The degradation of pesticide was assumed to be a first order kinetic process, and the degradation constants were obtained from literature. The model was validated using data obtained for carbofuran in a column leaching study, where the soil column was initially saturated with water. Four soils were used, including two ultisols, one alfisol and one inceptisol. A known carbofuran concentration was applied to the surface of the column and was thereafter followed by carbofuran free solution. The leachate samples were analyzed for carbofuran concentrations and leaching was continued until the carbofuran concentration in the leachate is undetectable. In curve fitting the numerical solution of the transport equation to the observed data, it was assumed that the solution sample represents volume-averaged concentrations. The average pore velocity was calculated by dividing the soil water flux by volumetric moisture content. In all soils, the model prediction fitted well to the observed data for carbofuran. This model therefore can be used to predict the concentration of carbofuran in moving water at any soil depth, given the soil conditions. However, to use this model for other pesticides, preliminary information regarding adsorption and degradation should be available and the transport model should be modified accordingly.
A Pathological study of white spot syndrome in Prawns(Peneaeus Monodon)
(University of Peradeniya, 1998-11-07) Andarawewa, P. K. L.; Wettimuny, S. G. De S.
The study was carried out in order to determine the gross and microscopic changes in White Spot Syndrome in prawns as early diagnosis of the disease is very necessary to control and prevent its spread. Samples of prawns weighing 8 to 24g were collected from randomly selected ponds in the Chilaw and Puttalam districts from April 1997 to April 1998 during sporadic outbreaks of the disease. Details pertaining to the out breaks, management systems, water parameters etc., were recorded. After gross examination of the prawns the gills, stomach, hepatopancreas and gut were fixed in Davidson's fixative for 24-72 hrs. They were then transferred to ethanol. The tissues were carefully trimmed, cleared and paraffin embedded. Paraffin sections were cut at 6~ and were stained with hematoxylin and eosin. During disease outbreaks there was a rapid reduction in feed intake with onset of high mortality within a few days. Most of the shrimps were seen surfacing frequently while some were seen at the pond edge. The majority of shrimps had white spots of 0.5 to 2mm in diameter on the cuticle. The histological sections of stomach, gills and mid gut revealed intranuclear eosinophilic to pale basophilic inclusion bodies in the epithelium. Some cells exhibited nuclei with basophilic marginated chromatin. Few inclusions were present in sections of mid gut. The inclusions were totally absent in the sections of hepatopancreas examined. The gills revealed certain structural changes in the lamellae. The lamellae were swollen and the cuticular layer was found separated from the underline tissue. The gross signs and histological changes were similar to those reported in literature.
A Preliminary study on the mode of inheritance of cleft lip and cleft palate patients
(University of Peradeniya, 1998-11-07) Arambawatta, A. K. S.; Chandrasekara, Malkanthi; Nanayakkara, D.
The mode of inheritance of cleft lip and cleft palate was studied in 35 cleft lip and cleft palate patients who attended the Teaching Hospital, Peradeniya and the Dental Hospital, Peradeniya during the period of July' 97 to September '98. The sample consisted of22 males and 13 females. Information regarding age, sex and ethnicity was recorded. Parents of cleft patients were interviewed to obtain the family history, medical history and dental history. The oral cavity was examined with a mirror and probe and the type of the cleft was recorded in each patient. Of the 35 cleft patients 18 (51.5%) had either unilateral or bilateral cleft lips and 17 (48.5%) had unilateral or bilateral cleft palates. The total sample consisted of 29 cleft lips and 27 cleft palates. Of the 35 cleft patients 5 (1.4%) had a family history of clefts and 5 (1.4%) had parents with consanguineous marriages. Mothers of two patients had taken anti-convulsant drugs during pregnancy. Pedigree charts of the five patients with a family history of cleft were drawn. Only two complete generations were included in the pedigrees. Analysis was done by the simple counting method to establish the pattern of inheritance. An autosomal dominant mode of inheritance was looked for. The paternal or maternal side of the pedigree was identified as informative. The total number of informative subjects were counted and classified as positive or negative. Irrespective of sex of the 184 informative subjects, 11 were positive and 174 were negative. With an autosomal dominant mode of inheritance 92 subjects would be expected to be positive from a total of 184, giving a ratio of 1: 1, irrespective of the sex. The observed number of 11 is significantly different from this value of 92. In this preliminary study autosomal dominant mode of inheritance was not observed.
A priliminary study on the prevalence of cemental caries in a Sri Lankan population
(University of Peradeniya, 1998-11-07) Ratnaweera, P. M.; Mendis, B. R. R. N.; Ekanayake, S. L. Samaranayaka, P. M.; Samaranayaka, P. M.
The exposure of the roots of the teeth to the oral environment has increased the prevalence of root surface caries, particularly that of cemental caries. The published studies that have documented the proportion of the population with untreated root surface caries report prevalences ranging from 17% for those over the age of30 years to 37% for over 50 years of age (Locket et al 1989). No data is available for Sri Lanka. Therefore a preliminary study was carried out to assess the prevalence of root caries in a Sri Lankan population. The sample for this study consisted of 85 patients aged 40 years and over from the village ofPanwilatenna in Udapalatha Divisional Secretariat in the Kandy District of the Central province of Sri Lanka. A visual intra-oral examination for caries was performed using a mouth mirror and explorer. Teeth present and root carious lesions were recorded on a custom designed form along with demographic data relating to the age and sex. The root caries index (RCI) proposed by Katz(1980) was used to record root caries. The index is represented in the following manner: (FORMULA) The RCI was calculated for each subject and the mean RCI scores by age and sex was analyzed. A total of 85 subjects aged between 40 and 80 years examined, 60 were females and 25were males. For the females; mean Root Caries Index was 0.65 and SD was. 1.61. For the males; mean RCI was 2.15 and SD was 6.60 (CHART) The results highlight the fact that Root Caries Index tends to increase with age and to be higher in males. RCI is increasing after the age of 50 years in females. These figures for both sexes are lower than those reported by other researchers abroad.
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.
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.
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.
Abuse, harassment and torture University style: a study of the forms and practices of ragging in the University of Peradeniya
(University of Peradeniya, 1998-11-07) Athukorale, K.; Pinnawala, S.
Department of Sociology, Faculty of Arts, University of Peradeniya. Legitimization of change of social status of individual members in traditional societies is done through a ritualistic process called initiation. A number of contemporary institutions are known to maintain similar traditions as part of their sub-culture. Ragging in the Universities is one such sub-cultural tradition. However, unlike the initiation rituals in traditional societies many of the modem day initiation practices are harmful to society and the individual. The aim of the paper is to understand the types and forms of ragging and to examine whether it can be considered an initiation ritual. The analysis is based on a survey that was carried out in 1995 in the University of Peradeniya. The use of 1995 data is justified as two years is not long enough to have any significant changes in the types and forms of ragging and its social basis. The study showed that ragging practices can be classified into two groups. The first is the activities that cause physical pain, leading even to injuries, on those who are ragged. The second is those that take the form of verbal abuse causing mental strain. The injuries caused by the latter are not often visible and immediate. Of the activities of ragging the majority fall into the first group. Ragging activities in the University show a parallel between hazing in the United States and ragging here indicating to a gradual Americanization of ragging in this country. Ragging in its physical form is predominantly a male activity. The clear majority of the students who are engaged in this form of ragging and those who are subjected to it are males. In inflicting mental abuse however both males and females showed similar involvement. Ragging across gender almost exclusively takes place in the form of verbal abuse. Ragging showed a close association with the socio-economic background of those who are involved. Contrary to the popular belief it is those who come from rural areas, regional schools and those who belong to low income groups are the ones who often get ragged and are very often the perpetrators of ragging. There is also a close relationship between ragging and political activities in the campus. Ragging is manipulated by political groups to recruit members. This happens in two ways. One way is to win the student over through sympathy. The other way is by subjecting one to extreme ragging. It helps to identify the stronger personalities and those who are won over in this manner remain loyal to the cause and the leadership. The claim that ragging promotes solidarity and friendship and also a great leveler is unfounded. Only a very small minority of those who get ragged continued to be friends with the raggers. Neither has it succeeded in promoting equality among the students. There is little evidence to show that ragging in its present form serves any function in the University community.
Acoustic quality of buildings
(University of Peradeniya, 1998-11-07) Dilhani, M. P. P.; Hussain, F. M.; Karunasinghe, D. S. K.; Somaratna, A. P. N.
Department of Civil Engineering, Faculty of Engineering, University of Peradeniya There are certain types of buildings whose acoustic qualities assume great importance. Some examples are: auditoria, concert halls, recording studios, and lecture theatres etc. In the design of such buildings careful attention has to be paid to achieving superior acoustic qualities. This study was aimed at exploring the available design practices with respect to acoustic quality and also at investigating the methods for the assessment of acoustic quality in buildings after construction. The acoustic requirements of different types of buildings are different. Rooms meant for speech such as lecture theatres should ensure that every member of the audience hears the speaker clearly. A concert hall needs to ensure that the music lingers on for a short time without dying down too rapidly. A recording studio for speech should minimize the reverberations. The most important parameter that governs the acoustic quality of such a room is the reverberation time. It is defined as the time taken for a sound to decay by 60 db. In addition, the sound level distribution within a room also is an important consideration. Both these depend on the geometric shape and the dimensions of the room, and the acoustic properties of the materials used in the construction of the room including the furniture. Some guidelines are available for the design of buildings with good acoustic qualities. For example, there are recommended values for reverberation time, volume per seat, ratios of room dimensions etc. There are recommendations regarding the shapes of rooms, roofs, ceilings etc. These guidelines were compiled as the first step in the present study. In order to investigate their effectiveness two lecture rooms in the Faculty of Engineering - viz. room no. 9 (considered to have poor acoustic qualities) and room no. 2 (thought to have good acoustic qualities) - were selected for experimental testing. The dimensions of these rooms were compared against the recommendations. The reverberation times of each of these two lecture rooms were first computed using analytical methods. Then they were measured experimentally and the values were compared with the recommended values. In addition the sound level distributions within each room were studied to see whether there were any areas of poor reception. Based on the results the following conclusions were drawn: (a) The guidelines given in literature for good acoustic design of buildings do in fact help to produce good results. (b) The analytical procedures available for the calculation of reverberation times are capable of yielding satisfactory estimates and the reverberation time is a good measure of the acoustic quality of a room. (c) Proper design procedures which pay adequate attention to guidelines regarding acoustics can improve the acoustic quality of buildings a great deal.
Adenomatoid Odontogenic Tumour(AOT) in the Posterior Mandible with Unusual Presentation
(University of Peradeniya, 1998-11-07) Gunatilaka, B. R. P. L.; Mendis, B. R. R. N.; Amaratunga, E. A. P. D.; Ranasinghe, A.
Department of Oral Pathology, Faculty of Dental Sciences, University of Peradeniya, and * Dental Institute, Colombo The WHO classifies the AOT as an odontogenic tumour, derived from the epithelial components of the developing tooth germ. The recent literature suggests that the odontogenic ectomescenchyme plays a part in the pathogenesis of this turnour. The early cases have been reported as glandular adamantinoma, pseudo-adenoma adamantum or adenoameloblastoma. Philipson named the turnour Adenomatoid Odontogenic Turnour. Some authors however believe that the AOT is a harmatomatous lesion. The AOT accounts for about 0.1% of all turnours and cysts seen in the jaws. It comprises about 3% of all odontogenic turnours. Case Report: A 13 years old girl presented with pain in relation to the 61. On examination there was pain on percussion and exaggerated response to pulp testing with heated G.P. Radiologically, a radiolucent lesion could be seen in the right side of the mandible extending from 41 to unerupted 8i region. An incisional biopsy was done. The clinical diagnosis was aneurysmal bone cyst. Microscopically , the connective tissue contained many proliferating epithelial islands arranged in the form of islands, cords and knots. There was also evidence of abnormal calcification in the connective tissue. Also the lesion seems to merge with the oral epithelium. Myxomatous tissue with irregular calcification could also be seen.These histopathological features are consistent with that of an AOT in relation to the 876541 region. T he definitive surgery was done and the unerupted 81was removed with the lesion. The patient is being followed up at the Dental Institute, Colombo. What makes this case unusual is summarized below. resent case Diagram is available in Pdf copy of the abstract.
Agrarian Change in a Peasant Colony of Sri Lanka
(University of Peradeniya, 1998-11-07) Mendis, T. I.
Department of Geography, Faculty of Arts, University of Peradeniya. The capitalist form the agrarian transformation and differentiation is seen as a progress in social and economic terms. This thinking, based on the experience of now developed western world, compelled the development thinkers to advocate the need for the dissolution of peasant form of production in rice growing societies in the Asian region. However several researcher studies on wet rice agriculture in Asian region sow that rice growing societies in this part of the world experience a different type of agrarian change which is not a hindrance to the social and economic progress. In this context, present study examine and explain the agrarian change taking place in peasant colonies in Sri Lanka in order to see whether we need a capitalist mode of agricultural development in Sri Lanka. The qualitative research craft provided the basic guidelines for the present study which is mainly based on the field study carried out in two selected villages in the Minipe Peasant Colonization scheme in Sri Lanka. This study localities were selected to represent to older phases of settlement development in Minipe Scheme. Two non random samples each for one village to comprise thirty respondent from one village were used to generate empirical data. Indepth interviewing constituted the main method used in collecting information. Temporal scope of study covered two decades period from 1977 to 1997. In addition to this, secondary sources were consulted to obtain the background information relating to the Minipe Colonization Scheme.
Allelopathic Effects of Gliricidia(Gliricidia Sepium) and Ipil Ipil (Leucaena Leuconcephala) Green manure on Seedling Growth of Rice Maize and Cowpea
(University of Peradeniya, 1998-11-07) Gunasekara, J. M. D. M.; Jayakody, A. N.
Department of Soil Science, Faculty of Agriculture, University of Peradeniya. There are ample evidences that some plants found in intercropping systems and organic residuce of those produce and release chemicals to the environment which may interfere the performances of other crops. Such chemicals cause reductions of the growth of neighbouring crops which is termed as allelopathy. Hence the allelopathic effects of Gliricidia and Ipil-Ipil green manure on seedling growth of rice, maize and cowpea were tested adopting a pot experimental technique as these are been frequently used as green manures for other crops. Seedling biossays were conducted in acid washed sand, in a Reddish Brown Earth soil (RBE) and in a Immature Brown Loam soil (IBL) of Sri Lanka to ascertain the modifications of the allelopathic effects by soils. The experiment was conducted in a poly-tunnel and duration was 5 weeks. Green manures were incorporated to above substrata at a rate representing 3tJha dry matter. Each pot was consisted of 500 g of substratum and moisture levels were maintained at 60% maximum water holding capacity throughout. The treatments tested were substratum alone, substratum with Gliricidia and substratum with Ipil- Ipil. The treatments were triplicated. Plant heights and internode lengths were measured at weekly intervals. Root and shoot dry matter were determined at the harvest. N,P and K taken up by the plants in each pot was also determined. The results showed that the Gliricidia has negatively affected the growth performance of cowpea, rice as well as maize. This effect was to be seen only in relation to shoot dry weight in cowpea, root dry weight in rice and maize and N uptake in rice. N uptake in Ipil-Ipil treatment was reduced in rice. Besides, the modification of the possible allelopathic effect could be observed by different substrata. Growth performances by Gliricidia in RBE soil was significantly lower than the control whereas in the IBL the effects were not much considerable. When growth parameters were considered the plant heights were not affected by green manure, but the dry matter yields and N, P and K uptake have shown negative and positive differences. Negative effects observed may have been caused either by allelochemicals already present in green manure or by the chemicals produced in the process of decomposition. Hence, it could be concluded that there may be negative effects of green manure on different crops which may be modified by different substrata. Thus it is appropriate to test the compatibility of crops to different green manure before use to achieve maximum benefits in improved cropping systems.
Alluvial Placer Minerals in the Walawe Ganga Basin with Special Reference to Gemstones and Gold
(University of Peradeniya, 1998-11-07) Nawaratne, S. W.
Department of Geology, Faculty of Science, University of Peradeniya. Sri Lanka's gemstones have been among the most known gemstones in the world. Most of the gemstones of Sri Lanka come from the south-western part of the country, however, north-central and southern parts have also contributed largely. In the Walawe Ganga basin which lies at the boundary zone between the Highland Complex and the Vijayan Complex a variety of gemstones of occur. They include precious stones such as blue-sapphire, ruby, star- sapphire, star-ruby mainly and also cat's eye and alexandrite. Various colours of spinel, zircon and tourmaline and chrysoberyl, topaz and gem quality quartz which fall into the semi-precious category are also common. The gemstones invariably occur in the placer sediments which are characterized by mostly rounded or sub-rounded quartz pebbles and gravel. These sediments mainly occur in the stream-beds and flood plains. In addition to the gemstones the interface zone between the gem-bearing layer and the underlying 'malawa' contain variable amounts of gold particles. The gold particles vary from dust size particles to nuggets weighing more than 1.5g having a length of about 7mm. The composition of gold grains varies from almost pure gold to natural gold-silver alloy known as electrum having Au to Ag ratio of 3:2. The gold content in the sediments goes up to levels as high as 9g of gold per ton of sediment which could be considered as economical concentration for exploitation. The rocks of the area falls well within the Highland Complex consisting of crystalline limestone, charnockite, quartzite, garnet granulitic gneiss, biotite gneiss and schists containing graphite and garnet. The rocks are commonly intruded by dykes and numerous pegmatites and quartz veins. The weak structural zones such as fractures and shears are characterized by sulphide bearing mineralization and some alteration assemblages. These mineralized alteration zones, intrusive rocks and skams of the area appear to be the source of gem minerals and gold.
Ambewalamides A and B, Novel Antineoplastic Compounds from a Sri Lankan USNEA SP
(University of Peradeniya, 1998-11-07) Karunaratne, V.; Bombuwala, K.; De Silva, E. D.
Department of Chemistry, University of Peradeniya *Department of Chemistry, University of Colombo Lichens produce a wide range of natural products and many are unique to lichens and an appreciable number have been shown to have antimicrobial, and other biological activities of potential medicinal value. The present study describes the isolation of two novel endodisulphides from an Usnea species. Specimens of the Usnea sp. were collected from the surface of a decaying tree, identified asAcacia deccurens in Ambewala, Central Province, Sri Lanka. The air- dried lichen (950 g) was exhaustively extracted with CH2Cl2 at room temperature to give a crude gum (5.1 g) that was fractionated via silica gel medium pressure liquid chromatography (eluent: step gradient from hexane to MeOH/CH2CI2, 4:96), silica gel preparative chromatography (eluent CH2CI2) and Sephadex LH-20 chromatography (eluent: CH2CI2/MeOH, 2:8) to give a crystalline fraction that contained the mixture of ambewelamides A and B. Final purification was accomplished using normal phase HPLC (Waters Radical PAK cartridge; eluent: CH2CI2/McOH, 20: 1) to give 13.4 mg of ambewelamide A and 1.4 mg of anbewelamide B, both as optically active, clear crystalline plates. The structure of the compounds were elucidated by a combination of high resolution FAB mass spectroscopy, and lD and 2D NMR (COSY & HMBC) spectroscopy. The final confirmation was arrived at by single crystal X-ray diffraction techniques. Ambewelarnide A exhibited potent in vitro cytotoxicity (murine leukemia P388: IC50 = 8.6 ng/ml.) and it also showed significant in vivo antineoplastic activity (P388: % CIT 140 @ 160 ~lg/Kg). To [he best of our knowledge, this is the most potent and most promising anticancer compound to be discovered from a Sri Lankan source (both terrestrial and marine). Diagram(See the pdf version of the Scanned copy) Ambewelamide A: R = (CHz) ZCH3 Ambewelamide B: R = (CHz) 4CH3
An approach for irrigation scheduling in an irrigation system
(University of Peradeniya, 1998-11-07) Ratnayake, U. R.; Nandalal, K. D. W.
The demand for water in recent times has increased due to new developments in water uses and climatic changes. One of the major uses of water is in irrigation schemes. The emphasis has therefore shifted to optimally operating these systems to minimize waste of water. This paper presents a model, developed to optimally operate a diversion type irrigation scheme. A technique is developed to particularly apply in diversion schemes where a constant water requirement is preferred. Dynamic Programming (DP) is selected as the optimization technique due to its ability to incorporate non-linear objective functions and constraints. The model optimally allocates irrigation water to different plots along a main canal. This spatial distribution is limited to a single time step and the optimum results are sequentially integrated in time to form the final policy. Physical canal properties of the system such as reach length, maximum canal capacities, area of plots, evapotranpiration and rainfall are the initial inputs required for the model. The modeling process is separated into two stages. In the first, weekly total irrigation requirements of each plot were estimated and various different patterns of daily releases during the week were derived to supply these requirements. The second stage applies DP to find the best combination from these alternatives, which provide a flow with a least amount of deviations within a period. The model is applied to GampoIawela Rajaela Irrigation Scheme in the Kandy District to test the applicability. The scheme irrigates a command area of 162 ha by diverting water from UIapane Oya. The command area is divided into seven tracts located along the canal. The last tract of 77 ha is fed by a feeder canal bringing water from Mahaweli river. < * Comparison of observed and optimum releases in the canal- Yala 1997 Figure 1. is in original Article, Detailed diagram is availble in Pdf> The results show the effectiveness of the developed model. The optimum releases have lesser fluctuations compared to the observed releases. Also, it allocates water efficiently. The model could be applied at the planning and operational stages.
An examination of learning styles of undergraduates in different academic disciplines
(University of Peradeniya, 1998-11-07) Perera, E. B. P.
The objectives of this study is to investigate whether there is a pattern of distribution in the learning styles of undergraduates in different academic disciplines of Sri Lankan universities. Some of the background variables associated with learning styles were also investigated. The sample consisted of 1138 first year undergraduates of three Sri Lankan universities in the disciplines of arts, Engineering, Medicine, Management, Science and Agriculture. A Sinhala version of Kolb's Learning style inventory was used to identify the learning styles of Undergraduates. In addition to this a short questionnaire was utilized to obtain relevant information for the identification of background factors associated with student learning styles. The investigation revealed some important findings. There is a clear differentiation of learning styles between students in Arts, and Science disciplines and this is parallel to Hudson's Arts/Science converger/ diverger differentiation. The learning styles of undergraduates in Engineering , Medicine, Management, Science and Agriculture except in the arts discipline were significantly unequal in distribution. The learning styles in these disciplines were directed towards the converger style. This shows a similarity between universities in western counties and in Sri Lanka. Occupations of the fathers and parental education were found to be background factors in the accentuation of learning styles of students. It was revealed that the children of fathers in higher occupational levels were convergers while children of fathers in lower occupational levels were divergers and the children of parents who had obtained a higher educational level were convergers. These findings show Kolb's Inventory could be successfully used in the identification of students learning styles and confirms the validity of further use as an instrument in the identification of student learning styles.

Browse

Browsing PURSE 1998 by Title

Results Per Page

Sort Options