PURSE 2000

Permanent URI for this collection

https://ir.lib.pdn.ac.lk/handle/20.500.14444/46

Browse

Now showing 1 - 20 of 33

Design and construction of an electronic water level indicator
(University of Peradeniya, 2000-12-16) Bandara, H. M. P.; Dissanayake, M. A. K. L.
The increasing availability of low cost semiconductor devices has led to the rapid proliferation of economical electronic devices applicable to all aspects of life. However. in Sri Lanka. though there is a large market for electronic devices of all types. design and development of new electronic devices remain a weak sector. For those who depend on water from an overhead tank. it is important to know the amount of water available in the tank. This is particularly important when the main water supply is not reliable. The possibility to know the amount of water in an overhead tank without having to frequently access it is therefore important and useful. Commercially available water level indicators are expensive and needs frequent care and maintenance. The aim of this project is to design and construct an electronic water level indicator using readily available low cost electronic devices and materials. In designing the instrument special emphasis was laid on minimising cost without compromising accuracy. At the same time a special effort was made to make the instrument simple and thereby reducing the need for maintenance.
Retroesophageal right subclavian artery
(University of Peradeniya, 2000-12-16) Banneheka, B. M. H. S. K.; Samaraweera, P.; Satoda, T
Retroesophageal right subclavian artery is a congenital anomaly of the aortic arch which is said to be found in a frequency of 0.2 - 2.5 % (Rahman 1993). A cadaver of a 45 year-old Sri Lankan male with this anomaly was found during a routine dissection class. Instead of its normal origin from the right brachiocephalic trunk, here the right subclavian artery (RSA) originated independently from the arch of aorta as its fourth branch, i.e. dorsal and distal to the left subclavian artery. A KommereII's diverticulum was observed at its origin (42 mm in diameter) Then the artery coursed upwards behind the trachea and the oesophagus to the right side of the thoracic cavity where it was distributed as the normal artery. The right inferior laryngeal nerve passed directly into the larynx as a non- recurrent laryngeal nerve The oesophagus showed a marked oblique groove (37 mm long and 6 mm deep), on its posterior aspect where it was in contact with the RSA This is known to be an unusual cause of dysphagia ("dysphagia Iusoria") in adults. The subclavian artery and the recurrent laryngeal nerve on the left side had a normal course of origin and distribution.
Skanda as a guardian god of Lanka the significance of the Tamil slab-inscription from Budumuttava
(University of Peradeniya, 2000-12-16) Pathmanathan, S.
The god of Kataragama identified by many as Skanda is one of the four guardian-gods of Sri Lanka. These guardian gods occupy an important position in the Sri Lankan Buddhist tradition and images of these divinities are found installed in many Buddhist temples. Besides, there are many separate shrines called devale dedicated for the worship of these divinities; also other are separate devales dedicated only to these deities. One of the earliest of such shrines could be assigned to the 14th century. Many of them are endowed with lands granted by kings in former times. Each devale has a traditional system of management in respect of temple ; services and the administration of its endowments. The importance of the guardian gods is highlighted by the perahera or annual festival. In Kandy, four guardian-deities namely Skanda, Visnu, Natha and Pattini - are venerated annually in the of Esala Perahara in colourful procession held along with the procession of the Temple of the Sacred Tooth Relic. This festivalhas been conducted with an almost unbroken continuity since the 17th century'. This annual festival is said to have been re-organized on an elaborate scale under Kirtti Sri Rajasingha in the 18th century.
A study of the musical poetical forms and their contribution to the emotional expressions in the sokari drama
(University of Peradeniya, 2000-12-16) Seneheweera, L
Kolam, Nadagam. and the Sokari have been established as the folk drama in Sri Lanka. Kolam is a kind of a dramatic pcrfonnance. which survives today chiefly in coastal townships in South in Sri Lanka. particularly in Ambalangoda and Bentara. Nadagamas have been popular mostly in villages and townships along the western coast. from Chilaw in the north right down to places like Tangalle in the South. The Sokari is a folk ritual drama with much dramatic entertainment. confined to the Uda Rata and the Vanniya. Presently it is performed in the villages around Kandy. Traditions of Sokari performed at Uda Dumbara. Matale. Konakallagala. Vehigala arc well known, This ritual play in many of its tradition is performed to get the blessings of the goddess Paththini, However. in some tradition Kataragama with that part is emphasized: the story enumerates how Guruhamy and Sokari after their marriage came to Sri Lanka from South India to visit the famous devale of Kataragarna in order to get the blessings of that god to beget a child. The story is dramatically presented by players who resort to mime. dance and stylized movements as a backup for the normal prose and verse dialogue. In addition. there is much variation in poetical forms. although it may seem monotonous for a non-initiate. The play is lyrical and consists of a large number of verses. These could be divided into two categories of metrical and non-metrical composition, both of which could again be subdivided into measured and unmeasured forms: a large number of meters including Samudurugos. yagi. so on. Furthermore. it uses a large number of poetical forms such as sivupada. gi. sahali. as well as musical forms of rhythm. melody. and tempo. One could sum up that Sokan play is based on the genuine folk. poetical. and musical traditions of the upcountry tradition of Sri Lanka. The aim of the present research is to highlight this basic musical tradition,
Managing shoot borers by using acacia auriculiformis as a nurse crop for establishing mahogany seedlings
(University of Peradeniya, 2000-12-16) Mahroof, R. M.; Edirisinghe, J. P.; Hauxwell, C
TIle main factor. which has limited cultivation of mahogany. Swietenia macrophylla, King (Meliaceae: Swietenoideae) is damage by shoot borers (Hypsipvlo spp.). Attack results in destruction of the apical shoot, causing branching of the tree. and significantly reducing the economic value of the timber. Although shoot borers have been intensively investigated no consistently effective control methods currently exist. However, some observations suggested that overhead shade provided by a nurse crop during early growing phase of mahogany seedlings might reduce the attack. Yet much of the information available is anecdotal. Although shade reduces attack by shoot borer. mahogany being a light demander. shade also may reduce the growth of seedlings. Hence a study was designed to assess the effect of different light availability on survival, growth and attack by shoot borers under different light conditions. This study was done from 1997-99 at three sites. two from Rambukkana and one from Mirigama under a nurse crop .-Icacia auriculiformis A. Cunn. Ex Benth. (Miruosaceae). Each site composed of three plots with different canopy openings of high. medium and low shade obtained by pruning of Acacia trees. Within pruned area (5 m x 5 m), 18 mahogany seedlings of similar origin. age and height were planted. TIle Photosynthetically Active Radiation (PAR) reaching each plot was measured using a data logger with a PAR sensor. Pattern of flushing and growth of mahogany seedlings were recorded monthly. Number of shoot borer attacks per plant was recorded l~ months after planting. Relative PAR values in the three sites varied from 21.6 ± U % in the higher shade gap to 93.1 ± 3.3 % in tlle lower shade gap. Seedling survival a year after planting did not show significant differences between light regimes. Under low shade. seedling height was 57.~ % greater than under high shade. and was highly significant in ANOYA (d.f.=2. P=0.00(1). TIle root collar diameter under low shade was U ± 0.09 em, while that under high shade was 0.8 ± 0.04 cm (d.f=2, P=O.OOUI).Seasonal variation in shoot phenology showed a similar trend in all shade regimes. with increased flushing observed during the rainy period, but shoot remained dormant during the dry spell. Number of attacks per plant in low shade plot was 112 times higher than under high shade (d.f=2. P=O.OOOI).Observations of this study show that high shade (20-30 % PAR) reduces growth of mahogany even though it might reduce attack by shoot borer and the best rapprochement to manage shoot borer problem while achieving reasonably good growth would be medium shade conditions (~5-50 % PAR).
Investigating the possibilities
(University of Peradeniya, 2000-12-16) Padmasiri, S. I.
Prawn-shell derivatives extracted in the laboratory in two different methods were tested for their turbidity removal efficiency and pH dependency and the results were compared with those of alum and commercially available chitosan. One method gave a product which behaved similar to commercial chitosan in turbidity removal efficiency. It was discovered that the diluted supernatant also showed very high turbidity removal capabilities.
Effect of environmental physiological and managemental parameters at insemination on conception rate of exotic (European) indigenous cows
(University of Peradeniya, 2000-12-16) Perera, E. R. K.; Udayanga, H. N. R.; Jayaweera, N.; Perera, A. N. F.
One hundred and one Exotic (European) * Indigenous crossbred cows presented for artificial insemination (AI) at Pannala Veterinary Range from April to July. 2000 were used to examine the effect. of environmental temperature (ET). various physiological parameters of the cows. and management factors at the time of insemination. on conception rate (CR) of Exotic (European) * Indigenous crossbred cows in Sri Lanka. Data on breed. age. parity, date of last calving, average daily milk yield and interval from detection of heat to insemination (IDI) of each cow were recorded based on the information provided by the owner. Environmental temperature (ET), vaginal temperature (VT). rectal temperature (RT). pulse rate (PR), respiration rate (RR), length and width of vulva, and body condition score (BCS) of individual cows at the time of insemination were measured. Heat signs (HS) of each cow at the time of insemination were assessed by adopting a scoring system, which assigned a score for each heat symptom examined. based on its intensity of expression, Two experienced technicians performed all 101 inseminations. Time of insemination and inseminator number were recorded for each insemination. Per rectal pregnancy diagnosis was performed at 75 days after insemination. Data were subjected to correlation and regression analysis. and analysis of variance procedures. Mean ET at the time of insemination was 31.2 ± 1.5 "C. resembling the typical daytime temperature conditions prevailing during these months in the intermediate zone of Sri Lanka. Mean age, parity, days postpartum (OPP) and BCS of cows were 5.39 ±2.74 yr, 2.52 ±1.55, 213±115 d and 2.7-1-± 0.65, respectively. These values suggest that the cows included in the study were a representative sample of the normal population of breedable cows. Mean PRo RR. VT and RT of 101 cows at the time of insemination were 68.-1-±2.4 beats/min. 24.6 ±1.5 breaths/min. 39.-1-5±0.38 °C and 38.5 ±0.4 °C, respectively. The values of physiological parameters were within the nonnal range for cattle. Relationships between ET at the time of insemination. and individual PRo RR, RT, and VT were positive. indicating increase in body temperature at higher ET despite induced thermoregulatory responses. Mean VT was 0.9 ± 0.1 ° C higher than mean RT in cows. and VT and RT were positively correlated (r = 0.58. p<0.05). Conception rate (65.-1-±1.2 %) was not significantly different between the two technicians. CR was highest in cows with BCS of 2 to 3, parity of 2 to 3. between 61 and 150 DPP. and when ID! was <13 hr. Inseminations performed after 19 hr lapse from detection of heat were not successful. CR declined (p < 0.05) by 8%,3.9"10. 5.2% and 4.9% with every 1°C, O.I°C. D.l°C and 1 hr increase in ET, RT. VT. at the time of insemination. and delay in time from detection of heat to insemination. respectively, CR was lowest when ET. RT. VT, and IDI at insemination were above 31.7 °C. 38.6 "C. 39.6 "C. and 19 hr. Highest CR resulted from inseminations performed whenET. RT. VT. and IDI at insemination were below 30.9 "C. 38.2 °C, 39.3 "C. and 13 hr. respectively. These trends are in the same direction. but the values are different to those reported for Holstein cows. The results suggest that CR in Exotic (European) * Indigenous cross bred cows in the sample was affected by ET. RT. yr. BCS. parity. DPP and IDI. Highest CR was resulted from inseminating cows having BCS of 2·3. parity of 3. between 61 to 150 DPP. within 13 hours of detection of heat. and when ET. RT. VI' were below 30.9 "C, 38.2 "C, and 39.3 "C. respectively.
Is the pattern of invasion a reliable predictor of metastasis of oral cancer
(University of Peradeniya, 2000-12-16) Siriwardena, B. S. M. S.; Tilakaratne, W. M.
Although oral cancer accounts for over 35% of all the cancers in our patients, there is no reliable way to predict prognosis. Various studies have shown different relationship of histological features to prognosis. but the results are not conclusive. Arrangement of cells at the advancing front of the tumour may playa significant role in predicting prognosis. Metastasis is considered as a key clinical and histological parameter which decides the outcome of a given patient. Therefore the aim of this study was to compare the relationship between the pattern of invasion and metastasis. Fifty cases of oral squamous cell carcinoma which have been excised with the neck lymph nodes, received at the Department of Oral Pathology, Faculty of Dental Sciences, University of Peradeniya from July 1999 to August 2000 were selected for this study. Pattern of invasion has been graded as type 1.2.3, and 4 according to the arrangement of tumour cells at the advancing front. Statistical analysis showed metastasis of 22% in type 2. 50% in type 3, and 71% in type 4 oral squamous cell carcinoma patients. These results were statistically significant and the p value was 0.001
Changes in physicochemical characteristics in saanan goat milk throughout a lactation
(University of Peradeniya, 2000-12-16) Dangolla, A; Silva, I. D.; Gunawardena, A.
Values on cellular and physicochemical characteristics of milk are helpful to detect the degree of sub clinical and/or clinical mastitis in goats. Since these values are likely to change throughout a lactation, for diagnosis of mastitis, a correlation with the stage of lactation is necessary The objective of the present investigation was to examine the changes in cellular and physicochemical characteristics of goat milk throughout a lactation. Composite milk samples from 10 goats from a farm in Matara, were collected into sterile glass containers, sealed air tight, labelled, and transported in ice to the veterinary diagnostic laboratory of the University of Peradeniya. At the onset of sampling, the goats were either in their 2nd or 3rd lactation and were approximately 2 weeks after kidding. Seven successive samplings were done in approximately one-month intervals by the same person. The somatic cell count (See), California Mastitis Test (CMT) reading, electrical conductivity (EC) and chloride ion concentration (Cl %) were measured within 48-72 hours after sampling. The climatic data for the area were also recorded. Sampling commenced in July 1999 and continued till January 2000. Only thirty-eight samples were processed and analyzed, as all the 10 goats were not sampled on every occasion due to unavoidable circumstances. The mean SCC (xl03/ml) values on the 7 consecutive sampling dates were 380, 1055, 3087, 2495, 4460, 2931, and 1600; the EC (milliSiemens/cm) values were 4.80,5.34,432,5.34,4.55, 10.86, and 7.01; and CI % values were 0.08,0.08,0.08,0.06,0.06, and 0.11 %, respectively The chloride ion concentration was not analyzed on the first sample collected. The average temperature, relative humidity, and rainfall during the period were 28.3° F, 78%, and 1200 mm respectively The goats were fed with jak leaves, Bracharia brizantha, and Prima feed mixture, containing 9-12%,8.5%, and 15% protein, respectively on dry matter basis). A progressive elevation in the sce during the first 4 months, followed by a decline during the last two months was observed. However, 16 out of 38 samples analyzed had CMT scores> 1 indicating a substantial frequency of subclinical mastitis. Consequently, the increase followed by the decline in sec remained even after disregarding the high SCC values corresponding to > J CMT scores. There was no obvious difference in the values between the 2nd and 3rd lactation, at any of the sampling dates. A notable change was not evident in EC or CI% throughout a lactation. There is evidence in these data to suggest that there is an increase in sec throughout a lactation in Saanan goats and therefore, the sce values must be interpreted in relation to the stage of lactation. However, further studies on a larger number of samples are necessary to establish this 202 phenomenon on SCC (if any), in EC, or CI % throughout a given lactation. It appears that CMT readings on goat milk do not correspond well with SCC values when performed 48 hours after milk collection. This finding becomes important when dispatching and transporting goat milk samples to a distant laboratory, in order to detect subclinical mastitis in the field.
Study of callus formation and regeneration of selected rice varieties and transfer of sytheticcry1 Gene rice callus
(University of Peradeniya, 2000-12-16) Wickramaratne, N. A. A. D.; Bandara, J. M. R. S.
Rice (Oryza sativa. L) is one of the most important food crop of the world serving as a major staple food crop for about 3 billion people In developing countries, 35%.55% of the potential yield of rice is lost mainly due to pest and diseases. In South and Southeast Asia, the average yield lost due to insect pest is 18.5%. Mordern methods of important include gene transfer to obtain pest resistant varieties. Tissue culture is a principal tool in gene transformation. In this study callus formation and regeneration of selected rice varieties Bg300, Bg304. Bg380. Bg352, Bg350 & IR8 were examined. Seeds were cultured on R2 medium with two 2. 4-D levels (I mg/l and 2 mg/l). Callus formation percentage was observed after 2 weeks of culturing. calli colour was observed at first subculturing and size was also measured prior to transfer to the regeneration medium Rice calli (Bg352) were co-cultivated with Agerobateriurn.' . bi C\\rBI\ !1()! ith heti I strain C58 carrying recom mant vector p .. . . Wit synt etrc cry gene. Transformation efficiency was checked by the GUS assay. Bg352 was the best in callus formation with favourable colour and favourable size. It is also the quickest to respond bv becoming green when transferred to regeneration medium, , f l 'I'd II' GL'S" T DN'A f 'h C.\.\fB1.\ Fifty three percent 0 t ie co-cu tivate ca I were I positive - 1 part 0 t e p 1.101has integrated successfullv with a genome of Bg352.
Udas: an inquiry into the South Asian state of mind
(University of Peradeniya, 2000-12-16) Goonasekera, S.
A state of the mind known as udas is widespread in Rajasthan, India. Although accurate statistical infonnation regarding its distribution is hard to obtain. linguistic data indicate its prevalence throughout the South Asian cultural area from ancient times. In Rajasthan, in tile central regions around Jaipur, Bikaner and Jodhpur, in tile region known as Marwar where I conducted my field research. This is a well-known phenomenon. Adults of every age seem to experience this condition of being. Field data show and lexicographic research confirms that there is a common definition for this state of mind. According to the common definition, udas refers to a heart heavy with sadness. dissatisfaction one feels about one' s lot in life and disquiet about tile nature of the world and how people live in it. What are the characteristics of individuals who experience udas? How do the Jains identify, classify, and evaluate them? What methods are available in tile local culture to deal with this condition? What methodological and philosophical issues render the Jain cultural constructions about this mental state incommensurable with the psychiatric constructions about it? I address these issues in my essay.
Monocolonal antibody based flow cytometric method for the detection of enterotoxigenic clostridium perfringens
(University of Peradeniya, 2000-12-16) Piyankarage, R. H.; Uemura, T.
An assay combining flow cytometry (FCM) and C. perfringens enterotoxin (CPE) specific monoclonal antibody ( MAb ) was developed for the detection of enterotoxigenic Clostridium perfringens. Biotin conjugated anti-CPE MAb and fluorescent avidin was used to study the sporangia I cells of C. perfringens, which were collected from 6-8 hour sporulation cultures. Using this assay. eight strains of C. perfringens which possessed the enterotoxin gene and belonged to distinct Hobb s types were analyzed. FCM profiles of C. perfringens sporangia harvested from 6-8 hr sporulation cultures in Duncan and Strong (OS) medium revealed positive reaction for CPE. whereas vegetative cells and heat-treated sporangia of the same strain produced a negative reaction. Among eight different strains. high CPE producing strains showed high peak channel number and poor CPE producers demonstrated low peak channel numbers under FCM analysis. The flow cytometric method was found to be rapid, specific. accurate and reproducible. and can be used effectively in the detection of enterotoxigenic C. perfringens. Furthermore it might be of immense use in the diagnosis of food poisoning outbreaks.
Evaluation of Salmonella test method of Sri Lanka Standard Institute
(University of Peradeniya, 2000-12-16) Chandrasekara, R. A. N.; Jayasinghe, S.; Silva, I.
This study was conducted to evaluate the microbiological test method of Sri Lanka Standards Institution to detect Salmonella in foods. The SLS method was compared with the method published by Food and Agriculture Organization for detection of Salmonella by applying it to several food items. Black pepper. cinnamon, cardamom, cloves, and milk powder were artificially contaminated with Salmonella serotype H culture and uninoculated eggs were used for the study. A control test was carried out without adding the inoculum. Method of preparation of the food samples for isolation of Salmonella and the pre-enrichment media used. are specific for each food to be tested in the FAO method. However. SLS method employs the same preparatory procedure and the pre-enrichment media for almost all foods. Both methods gave positive reactions for artificially inoculated black pepper. cardamom. and milk powder. In the tests carried out for cloves and cinnamon by SLS method no positive reactions were observed whereas FAD method was able to identity the serotype H in these two spices. The anti-microbial substances in cloves and cinnamon appear to inhibit the growth of Salmonella by SLS method. In the fresh egg sample that was tested by the SLS method colonies were observed only in XLD agar. but not in Brilliant Green agar. These discrepancies observed for the test results for Salmonella leave room to suspect the applicability of the SLS method to foods.
Development of "EdRex" a computer pakage for the automation of examination procedures in the Faculty of Agriculture
(University of Peradeniya, 2000-12-16) Wickramasuriya, H. V. A.; Basnayake, M.; Angammana, A.
The efficient functioning of the Examination Unit is essential for the smooth administration of a university faculty. Therefore. the objective was to develop a software package for the Examination Unit. It was an in-house development through End User Computing at negligible financial cost. The package was developed as an application of Access' with Visual Basic'. Product development took two years during which time a Beta version and two other versions were rigorously tested. At present the product enables instantaneous registration of a full batch. of compulsory courses, and easy registration of optional courses. the generation of class lists. class attendance sheets. admission cards, examination attendance sheets. mark sheets. results sheets. and transcripts. Response time for each process is less than 2 seconds. enabling a very significant increase in the efficiency of the Unit. Some security features were provided. User support and training "ere provided. This package is currently being used in the Faculty and the response received has been extremely positive.
Grid connected wind turbines-Sri Lanka experience
(University of Peradeniya, 2000-12-16) Ekanayake, J. B.
All over the world wind energy sources are becoming widely used as environmentallv friendly. small scale energy sources. In Sri Lanka. first grid connected' wind farm is now installed in Hanbantota as a pilot project. In this paper a simple model. which can be used to represent a grid-connected induction generator especially as a fixed speed and a variable speed wind turbine. is presented. Modifications that are required in the model for the analysis of variable speed wind turbine are performed. The characteristics of the fixed speed and the variable speed operation of the induction generator are obtained using the mathematical model developed. The wind statistics obtained from a site 2 km away from the pilot wind farm in Sri Lanka is analyzed. The output yield so far from this pilot wind farm is compared with the expected output. Advantages of variable speed wind turbines oyer fixed speed wind turbines for the site studied is also discussed. Finally. problems associated with grid connection of fixed speed and variable speed wind turbines are highlighted.
Diagnostic testing of power transformer insulation by response measurements in frequency domain
(University of Peradeniya, 2000-12-16) Mularachchi, K.; Fernando, M.
This paper presents results of frequency domain response measurements on field-aged power transformer insulation comprising oil and cellulose material (paper. pressboard. etc.). Different types of oil-paper insulated power transformers were selected from the hydropower stations in Sri Lanka. The loss tangent of the transformer insulation was measured over a broad frequency range. It is shown that the variation of loss tangent over frequency provides an easy classification of new and aged transformers.
An anlysis of legislation for protection of the environment and its impact on health
(University of Peradeniya, 2000-12-16) Gooneratne, I.; Gooneratne, N.
Health services in Sri Lanka are provided mainly through the Ministry of Health, local authorities, and private sector, but at present it is the government that is responsible to render public health! community health services. It is a known fact that the environment has an impact on health. For many years environmental health has been a legal responsibility of national and provincial health authorities, but the control of environmental factors affecting health has long been shared by other ministries, agencies and agents. The purpose of this study was to analyze the legislation for protection of the environment and its impact on health. Among the laws that have been enacted to protect the environment, quarantine and prevention of diseases ordinance, housing and town improvement ordinance, town and country planning ordinance, food act, cosmetic and drugs act, control of pesticides act, national environmental act, medical ordinance, urban development authority act, the nuisance act. central environmental authority law, and constitution of Sri Lanka and its amendments were shown to have an impact on health
Knowledge of patients regarding their disease condition following treatment at a general hospital
(University of Peradeniya, 2000-12-16) Kularatne, M. S. M.; Liyanagama, K. L. T. N.; Wanigasundara, P. C.
The aim of this study was to assess the knowledge of patients regarding their disease condition following treatment at a general hospital. A convenient sample of 100 patients who were leaving the General Hospital, Peradeniya, after obtaining care were interviewed using a pre-tested structured questionnaire, to determine their awareness of the diagnosis, any special investigations that had been carried out and the treatment plan. The patients were graded into 4 categories depending on the level of knowledge they possessed. It was found that on the whole, patients had limited knowledge about various aspects of their condition. Patients with chronic conditions were better informed than those who had reported with some acute problem. There was a tendency of patients who had received more formal education having more knowledge.
A device made to measure and control bite force of human subjects in recording EMG activity of muscles of mastication
(University of Peradeniya, 2000-12-16) Pallegama, L. N.; Pallegama, R. W.; Sitheeque, M. A. M.; Weerasinghe, V.S.; Ranasinghe, A.W.; Somaratne, A.P.N.
Electromyographic activity (EMG) of muscles of mastication is recorded for various research and clinical activities related to masticatory complex. Integrated EMG activity· as well as the degree of biting force generated depend on the number of motor units involved in contraction of the muscles. Therefore, in recording EMG activity of muscles of mastication the bite force has to be controlled. Further, subjects must have a visual feedback to control and maintain the bite force during the recording period. The objective of the present study was to design and prepare a reusable and reliable electronic device that can be used to control and measure the bite force of human subjects in recording EMG activity of muscles of mastication. This prepared transducer consists of a stainless steel bite piece that can withstand the bite force of humans within the elastic limit of the material. A strain gauge (KFG-I 0-120-C I L5 M3 S) was attached to the outer surface of the stainless steel bite piece to measure the strain that is directly proportional to the bite force. The strain gauge was connected to a bridge circuit and the resultant signal was passed through an amplifier and then fed to an analogue multimeter. The multimeter reading provided the visual feedback required by the subject. The EMG activity of masseter and anterior temporalis was recorded in ten dentulous young adults while maintaining the bite force with this transducer. The visual feedback given through the multimeter was sufficient for subjects to maintain the bite force during the recording period The bite piece of the transducer was placed in between upper and lower incisors on each subject and they were asked to maintain four different loads using the visual feedback. The EMG activity was recorded under four different loads in all subjects. The recorded EMG activity was proportional (y = 0.9) to the bite force and it can be concluded that with the aid of this device the bite force of human subjects can be satisfactorily controlled in recording EMG activity of muscles of mastication.
Interactions among bees, wasps and some agricultural crop adjacent to the secondary forest at Gannoruwa
(University of Peradeniya, 2000-12-16) Karunaratne, W. A. I. P.; Gunatilleke, C. V. S.; Gunatilake, I. A. U. N.
Bees and wasps are economicaly imporatant insects as pollinators and predators. Decline of these insects is of global concern because of its impact on agricultural productivity, biological control of pests, and genetic diversity. This decline has been attributed to reduction in their natural habitats and the heavy use of insecticides. In this study the diversity of bees, their nesting sites, and activities on 37 agricultural crop species cultivated in the research fields at Gannoruwa, were examined in order to identify the specific pollinators of the crop species. Weed species and plant species found in the adjacent secondary forests were surveyed to acess its role in maintaing the populations of beneficial insects. Pollen found in the scopa (pollen carrying hairs) of bees were examined to recognize their true foraging plants. Xylocopa colonies were found nesting in wooden logs close to the cultivated lands while Ceratina sp. nested in rose stems. Colonies of social bees were not in the vicinity. Sweep netting off the vegetation caught 21 species of bees belonging to 11 (':') genera and four families of which Apis cerana. A ..florea and Trigona iridipennis were the most frequent visitors. Of the agricultural crop species surveyed Ipomoea batatas, So/anum melongena, Cucumis sativus, Persea americana and Luffa sp. were mostly foraged by bees for collecting pollen and/or nectarHedyotis and Tagetes were among the non-agricultural species frequently foraged by the bees.A number of polinators appear to be generalists visiting both agricultural and non-agricultural plant species suggesting the importance of the latter in maintaining the populations of pollinators especially during the lean periods resulting from the harvesting of annual crops at the end of their growing season.

Browse

Browsing PURSE 2000 by Issue Date

Results Per Page

Sort Options