PURSE 2005

Permanent URI for this collectionhttps://ir.lib.pdn.ac.lk/handle/20.500.14444/52

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The effect of soil potassium on postharvest fungal diseases of banana
(University of Peradeniya, Sri Lanka, 2005-11-10) Weerakoon, W. R. W. M. A. U.; Abayasekara, C. L.; Adikaram, N. K. B.
Potassium (K) is generally known to increase resistance in plants against diseases and enhance quality. According to literature, application of K during the growth period of varied crops resulted in beneficial effects against disease development in 65% and deleterious effects in 28% of the cases studied. The objective of the current study was to determine the effect of K application to soil on natural disease resistance in fruits of banana cv. "Embul" to postharvest fungal pathogens. Plants obtained from tissue culture were grown in a completely randomized block design in two sites at the University of Peradeniya. Treatments consisted of four levels of potassium (as mutriate of potash), TO (0 g/pit), Tl (190 g/pit-recommended dose), 1'2 (380 glpit) and T4 (760 glpit) applied three times prior to flowering at 2,,5 and 9 months after planting together with Department of Agriculture recommended doses ofN (110 glpit as urea) and P (150 glpit as rock phosphate). Fruits were harvested 13 weeks after flowering and allowed to ripen at room temperature (28±1 0q. Intensity of freckle disease at harvest, anthracnose development from natural infections and following artificial inoculation and stalk-end rot during ripening were estimated. Presence of scIerenchyma tissue in the peel was observed. Soil, leaf and fruit peel were analyzed for N, P, K, Mg, Mn, Cu and Zn. Certain postharvest quality parameters, vegetative growth, flowering time and yield were also evaluated and compared with the control. The results were analyzed statistically by ANOYA (SAS computer package). Site 1 had four times higher soil K level than the Site 2 prior to treatment. Fruits harvested from Site 2 with 1'2 K level developed significantly lesser (P ~ 0.05) anthracnose disease than the control in artificially inoculated fruits. However, higher K levels (T4) enhanced anthracnose in contrast. The stalk end rot was less (P ~ 0.05) in fruits harvested from K treated plants. A progressive reduction of freckle disease was observed with increasing K levels and the reduction in T4 was significant (p = 0.05, Kruscal-Wallis test) compared to the control. Peel sclerenchyma was higher in fruits harvested from T2 plants. Fruit peel tissue from T2 plants contained higher levels of K. However, fruit peels from T4 had lower K than TO. Plants treated with all K levels flowered earlier than TO and recorded increases in growth and yield at T2 K level. Further the thickness of the fruit pulp was significantly higher in fruits at all K levels while the peel/pulp ratio decreased with increasing K levels. Other quality parameters measured (firmness of fruit or pulp, thickness of peel, pH of peel or pulp, total soluble solid content, shelf life) were not affected. Considering Site I, the application of K had no effect on disease development, sclerenchyma production, growth or yield. However, pulp thickness and total soluble solids content increased significantly in fruits treated with 380 glpit K (T2). Analysis of peel K content showed higher levels in the control compared to treated plants.
System reliability modeling of riveted wrought Iron railway bridges
(University of Peradeniya, Sri Lanka, 2005-11-10) Karunananda, P. A. K.; Dissanayake, P. B. R.
This paper proposes a methodology to predict the remaining service lives and estimation of the condition of riveted wrought iron railway bridges based on structural reliability theory. Fatigue and corrosion are two of the most vulnerable forms of damages in these bridges. In this study, how to model both of these processes in terms of remaining service lives of steel bridges is considered. When a member in a bridge is subjected to cyclic loading in a repetitive manner, it is liable to fail in fatigue, with the operating stresses well below the yield stress. For such a member, the failure can be modeled by the reliability approach as shown below, (Mathematical Formula 1 ) where M₁ is called the safety margin and it is the criterion used to express how close the element to failure; Nf is the total number of stress cycles that can be applied to the bridge material; Nn is the number of stress cycles that has been applied up to now. For corrosion, the proposed failure mode is as follows, (Mathematical formula 2) where M₂ is the safety margin, (As)(current) is the effective steel area present at the time of consideration and (As)(required) is the steel area required to carry the load. From fundamentals of reliability theory, failure probability for the first mode of failure is (Pf1,) and that of the second mode of failure ( Pf2) and these can be found as follows, (Mathematical formula ) If the total failure probability is Pf it can be mathematically represented as follows; (Mathematical Formula 3) Hence, total failure probability can be found if three components of failure probabilities are known. With a target value of failure probability, remaining service life and the current condition of the bridge can be determined. As a case study, nine spanned riveted wrought iron railway bridge has been selected and first component of failure probability has been found while others are currently being done.
Tooth dimentions of masillary incesors in realtion to body height, age and sex
(University of Peradeniya, Sri Lanka, 2005-11-10) Jayawardena, J. A. C. K.; Priyadarshani, A.; Nanayakkara, D.; Chanrasekara, M. S.
Odontometry has valuable contributions in establishing biologic differences between populations. The aim of the present study was to (i) establish the dimensions of maxillary incisors (ii) determine relationships of tooth dimensions to body height, age and sex. The study sample consisted of permanent maxillary incisors (135) extracted from adult patients attending Hospital Dental Clinics in Kandy, and Peradeniya. Age, sex, race and height of the patient was recorded. The length of total tooth (TTL), crown (CL) and root (RL) were measured on the labial side using a Dental vernier caliper to the nearest 0.1 mm. Mean TIL (mm) of males and females for the central incisor was 23.79 and 23.02, respectively. For the lateral incisor, they were 22.27 and 21.96, respectively. The mean RL (mm) of males and females for the central incisor was 13.39 and 12.72 and for the lateral incisor, they were 13.59 and 13.14, respectively. The ratio between CURL for the central and lateral incisors were 0.85 and 0.72, respectively. There was no significant difference in tooth dimensions between the two gender groups. A significant correlation was not observed between body height and any of the tooth dimensions. A positive correlation (P = 0.0 I) was found to exist between root length (RL) and age. Although the sample size of the present study was too small to establish norms for the Sri Lankan population, we were able to obtain tooth dimensions of maxillary incisors. The absence of a significant correlation between any of the tooth dimensions and body height indicates that tooth length is not a good parameter to determine body height. The positive correlation between root length and age denotes that with age, the root elongates due to the formation of cementum at the root apex.
Teacher attitudes to school based evaluation programs: a case study from a few schools in the Kandy district
(University of Peradeniya, Sri Lanka, 2005-11-10) Embekke, Susila Kumari
The school based evaluation system was implemented in 1999 based on the recommendations of the National Education Commission (NEC). It was an innovative change which aimed at assessing students in schools at regular intervals. The primary objective of this new scheme was to evaluate cognitive abilities, affective traits and psycho motor skills as well as personality traits of the students, thus eradicating the drawbacks of the existing system which focused heavily on evaluating cognitive skills only. This new program also included a follow up remedial action package aimed at improving any weaknesses identified by the assessment procedure. It focused further on improving the quality of teaching The research was conducted using a number of research sites which comprised three national schools, four 1 AB schools , four 1C schools and four type 2 schools. The sample consisted of 100 teachers drawn from the above 15 schools in the Kandy District. The subject areas which came under observation were Mathematics, Social Studies, Sinhala and Science. Primary data was collected using the Lickert Attitude Scale. This was followed by several interviews conducted with the chosen sample. Data was analyzed using both quantitative and qualitative research methods and techniques adopted in the Social Sciences. The findings from the study indicate several positive and negative aspects of the new scheme. The teachers were quite critical of the training provided to them before the scheme was implemented. They indicated that they need more guidance from the officers of the Department of Education to implement the change more meaningfully. This proved that the targeted outcome could not be reached due to the limited knowledge the teachers possessed about the implementation process. However, the teachers were of the opinion that the new scheme is more beneficial to the students provided it is implemented properly. They further added that more training and time is needed for the teachers to get acquainted with the system properly.
Teaching staff empowerment and the concept of academic freedom : the perceptions of social scientists
(University of Peradeniya, Sri Lanka, 2005-11-10) Ekanayake, E. M. A. S. B.; Maheswaran, S.
Unemployment among university graduates has been highlighted recently, and given much publicity by the media. In particular, the unemployment rate is very high among graduates in the Social Sciences. Undoubtedly, there could be a large number of reasons for this situation. However, one of the main reasons is the low degree of empowerment of academics in the Social Sciences. This paper presents an empirical investigation of the degree of the teaching staff empowerment and the academic freedom contributed to the relevance and quality of undergraduate education to mitigate graduates' unemployability in Sri Lanka. Institutions of higher educations are maintained for the common good and not to further interests of either the individual teacher or the institution as a whole. The common good depends on the free search for truth and its free expression. Academic freedom and empowerment of the mind are essential to these purposes, and apply to both teaching and research. In knowledge based socio-economic environment, it has been recognized that empowerment is an as intrinsic motivational factor that enhances work performance and value creation processes. In addition, theoretically academics are given a much higher level of academic freedom in executing their duties; hence academic freedom is regarded as a core concept in universities. Present studies emphasize mainly two areas: the management practices of empowering perceived by academic staff, and the current issue of the concept of academic freedom The degree of empowerment and the academic freedom have been measured in terms of five factors: power, information, knowledge, resources, and rewards passed on for university performance. Data was gathered through the distribution of a structured questionnaire among fifty academics. This questionnaire was analyzed by using descriptive statistical methods. It was concluded that academics of the Social Sciences are relatively empowered with power, information, and knowledge, while they lack resources and rewards.
The Satanic verses : a semantic kaleidoscope
(University of Peradeniya, Sri Lanka, 2005-11-10) Jayaweera, Careema
This research draws upon M.A.K Haliday's Systemic Functional Grammar to investigate the status of blasphemy with regard to the Islamic context in Salman Rushde's novel The Satanic Verses. In employing Systemic Functional Grammar, the study favours transitivity and interpersonal analysis at the level of lexicogrammar. Transitivity and Interpersonal analyses are deployed to highlight the complex of relations involved in the characters portrayed in the novel. This analysis pays close attention to both character and event in order to show that a narrative like, Rushdie's is a kaleidoscope in which a number of possibilities are brought together by varying meaning connections reflected at various levels of the grammar. In using the Hallidayan semiotic model, I enter the lexicogrammatical level in order to realize the semantics of a few selected extracts from the novel. At the lexicogrammatical level, the focus of interest is the clause. The clause is viewed as a unit, which has three different structures: the textual, the interpersonal and the experiential, each expressing a different semantic component-these components are mapped on to one another to produce a single wording. The Muslim outcry against The Satanic Verses stemmed from their conviction that the author of the novel had distorted the beliefs and practices enshrined in the Quran. However, I believe that the controversy that ensued and the hurt expressed by those who have read the novel may have partly risen from the misconception of the aesthetic conventions deployed by the writer. This analysis shows the wealth of information that surface when the text is subjected to a lexicogrammatical analysis. In the exploration of the projected episodes, the evaluation will show that the novel is a semantic kaleidoscope, which offers a number of angles of interpretation that the Islamic world can make use of, to their advantage. This exploration aims to focus on some of the strengths of the novel, which those who oppose the work have opted to look upon as weaknesses. (Diagram)
Tumor necrosis factor α and interleukin-1β in oviductal contraction: possible involvement of gamete/embryo transport
(University of Peradeniya, Sri Lanka, 2005-11-10) Kodithuwakku, S. P.; Wijayagunawardane, M. P. B.; Miyamoto, A.
Tumor necrosis factor a (TNFα) and interleukin -Iβ (IL-Iβ) are important mediators of cell signaling. The existence of the bioactive form of cytokines as well as their binding sites in the various reproductive tissues has been reported and interaction with other substances in the control of reproductive functions has been postulated. Thus, the effect of cytokines in the regulation of biosynthesis and secretion of oviduct motility related substances in the cow oviduct were investigated. The study was further extended to examine the possible autonomous TNFα/ IL-Iβ systems. In vitro microdialysis system (MDS) was utilized to observe real time effect of TNFα/ IL-Iβ on the prostaglandin E2 (PGE2), prostaglandin F2α(PGF2α), endothelin-I (ET-l) and angiotensin II (Ang II) secretion by the cow oviduct. The lumen of 10 cm long portion of each oviductal segment was implanted with a MDS system and TNFα (100 ng) or IL-Iα (10 ng) was infused. After extraction, levels of Prostaglandins (PG), ET-I and Ang II were measured using second antibody enzymeimmunoassay (EIA). Bovine oviductal epithelial cells (BOEC) were collected from non-pregnant Holstein cows during the follicular phase and cultured in Ml99 under standard culture conditions until monolayer formation. Cells in second passage were incubated for 24 h with TNFα (10 ng) or IL-Iα (1 ng). The mRNA expressions of BOEC for enzymes involved in PG biosynthesis (COX-2, PGFS, PGES) ET-l biosynthesis (ECE-I, ET-I), and Ang II biosynthesis (ACE-I) were evaluated using real-time reverse transcription-polymerase chain reaction (real-rime RT-PCR). The quantification of mRNA expression was done using LightCycler® Software. Four hour infusion of TNFα and IL-Iβ stimulates the oviductal secretion of PG, ET-l and Ang II. Treatments with TNFα and IL-Iβ resulted in significant elevation of mRNA expressions for COX-2, PGES, PGFS, ET-l, ECE-l and ACE- I.The results reveal that TNFα and IL-Iβ increase the PGE2, PGF2α , ET-I and Ang Il biosynthesis and secretion in the bovine oviduct. The increased levels of these bioactive substances in the oviducts may actively participate in the control of oviductal contraction-relaxation. It can be concluded that TNFα and IL-Iβ increase the biosynthesis and release of PGE2, PGF2a ET-l and Ang II and thus, may actively participate in oviductal contraction -relaxation to regulate the trans-oviductal transport of the gamete/embryo.
Use of canonical forms to achieve asymptotic feedback controllability of switched control systems
(University of Peradeniya, Sri Lanka, 2005-11-10) Perera, S. P. C.
A switched system is a hybrid dynamical system consisting of a family of continuous- time subsystems and a rule that describes how the subsystems switch among them. Switching among different system structures is an essential feature of many engineering applications such as power systems. Furthermore, switched control systems have numerous applications in control of mechanical systems such as aircrafts and satellites. The class of continuous-time time-invariant controllable linear systems can be stabilized by means of controller canonical forms. Such canonical forms are not known in the context of switched control systems since a simultaneous transformation of two linear systems is not straightforward. Here, our attention is focused in developing such canonical forms for the controllable switched systems consisting of two continuous-time time-invariant linear subsystems. In this research, the transformation matrices are constructed by arranging the suitably chosen basis vectors of the state space of the relevant switched system as columns. Moreover, the existence and uniqueness of such canonical forms are established. These canonical forms are then used to devise switching strategies that guarantee asymptotic feedback controllability of switched control systems, and this process can briefly be explained as follows. First, using the canonical forms, a manifold M which contains the origin of the state space of the switched control system is constructed. Then, the state is steered to the Manifold M from an arbitrary initial state x(O) in the state space in finite time. Finally, the state is asymptotically driven to the origin without leaving M. The type of canonical forms developed in this work guarantees the robustness of the aforementioned process. The canonical forms developed in this work enable us to devise the switching strategy for the aforementioned process due to the appearance of 'zeros' and 'ones' in the appropriate positions. Moreover, an upper bound for the number of switchings can be estimated by use of the canonical forms established in this work. As future work, the canonical forms of the switched control systems consisting of more than two subsystems can be developed. To achieve this, one may need a better understanding of the topological structure of the switched systems consisting of continuous- time time-invariant linear subsystems. Thus, the complete investigation of the topological structure of such systems should be carried out in order to obtain canonical forms in the general case.
Using fuzzy logic for adaptive role based access control for database security
(University of Peradeniya, Sri Lanka, 2005-11-10) Nawarathna, U. H. G. R. D.; Kodithuwakku, S. R.
One of the focuses of access control is protecting sensitive resources in the database of a system by determining whether or not a user is authorized to access those resources. The set of resources are usually static, and an access control policy associated with each resource specifies who is authorized to access the resource. Recently Role-Based Access Control (RBAC) was found to be among the most attractive solutions for providing access control for database security. Possibility of using RBAC approach to an environment with multiple policy domains further justifies the tremendous momentum seen in RBAC research in the recent years. The main objective of this research is to present a new RBAC model that provides additional level of security checks by extending an existing RBAC model, using Fuzzy logic concepts. The proposed model allows modeling of vague organizational security policies using fuzzy parameters. Also in contrast to current notion of RBAC, it provides both static and dynamic permission assignment. Every user requests to perform an operation on the database resources is validated through a Fuzzy Policy Evaluator. The Fuzzy Policy Evaluator determines whether a request to perform an operation on the database should be granted based on information such as the sensitivity level of the data being affected by the request, the type of request being made, and the need to write or read on those resources of the user making the request. Usually, such information is very difficult to determine precisely since the information depends on other attributes that are themselves imprecise or only partially known requiring a fuzzy approach. The report presents an algorithm for generating such fuzzy information based on their dependent attributes. The method is based on using fuzzy linguistic variables and some straightforward fuzzy decision-making.
Value of sialography and ultrasonography in the diagnosis of salivary gland diseases
(University of Peradeniya, Sri Lanka, 2005-11-10) Varathan, V.; Sivachandran, Y.; Sivakumaran, A.
Disorders of major salivary glands are relatively common and the most appropriate investigation for such disorders is often decided by the presenting symptoms of the patient. Sialography still is the most widely used radiographic method for examination of major salivary glands. Inflammatory and non-neoplastic diseases generally show changes in the ductal system. In many instances their clinical pictures are similar. However their sialographic images exhibit sufficient characteristic information for the clinician to arrive at a diagnosis. Ultrasonography is also one of the imaging methods used for examination of major salivary glands. The main application of ultrasonography in the diagnosis of major salivary gland disease is for differentiation of cystic or fluid-containing lesions from solid masses. Solid tumours larger than 5mm are readily visualized by ultrasonography because they are less echogenic than the surrounding normal salivary parenchyma. Fine needle aspiration biopsy also can be guided by ultrasonography in the diagnosis of salivary gland pathology. The aim of the study was to compare the diagnostic outcome of sialography and ultrasonography. A total of 29 patients referred to Division of Radiology for diagnostic sialography were included in this study. Of these 21 (72.4 %) had parotid salivary gland lesions and 8 (27.6 %) had submandibular salivary gland lesions. Having obtained informed consent, all patients were subjected to ultrasonography prior to sialography. The diagnostic outcome of the two techniques was compared. Eighteen patients (62.1 %) gave positive results for both sialography and ultrasonography investigations whereas 37.9 % of the patients did not. Each of these imaging procedures has its own value in the diagnosis of salivary gland diseases. But, ultrasonography being inexpensive, harmless and noninvasive technique could be used in combination with sialography to refine the diagnosis.
Serum testosterone level in captive male elephants (Elephas Maximus Maximus ) in Sri Lanka
(University of Peradeniya, Sri Lanka, 2005-11-10) Hettiarachchi, G. C.; Dangolla, A.; Watawana, L.; Udugama, J. M. C
Changes in Serum Testosterone Levels (STL) in captive male elephants were examined and categorized according to stage of musth (n=42), time of the day (n=4; 2 in pre- musth and 2 in non-musth) and age of the animal (n=32 in non-musth). The association between STL and the "temperament" of the captive elephants studied (n=33) during non- musth period was also evaluated. Further, attempts were made to determine the effect of anti- androgenic drug -"Flutamide" (250mg tablets) and "Oestradiol benzoate" (0.2mglml; "lntervet International B,V., Boxmeer - Holland") as means of controlling musth (n=I). Samples were collected during 6.00 h to 12.00 h except for the evaluation carried out to determine the variations of STL during the time of the day. Blood samples were collected from an ear vein and serum testosterone levels were measured by using the ImmuChemᵀᴹ radio immunoassay kit ("ICN Pharmaceuticals, Inc., Diagnostic Division, Costa Mesa, CA 92626"). The STL ranged from 0.02-27.33 nmol/L (n=32) in non-musth, 26.31-49.97 nmol/L (n=6) in pre-musth, 47.36 - >68 nmollL (n=3) in full-musth and 40.16 nmol/L (n=l) during post-musth period, respectively. Two male elephants in non-musth, at 6.00 - 12.00 h, 12.00- 18.00 hand 18.00 - 24.00 h, had STL of2.9 ± 2.7 nmol/L (n=2), 0.65 nmol/L (n=I) and 2.32 nmol/L (n=l ), respectively. Two other males during pre-musth also had similar pattern of STL, but slightly elevated levels. Average STL of adult elephants (10-25 years) was 5.92 ± \.5 nmol/L (n= 18), of prime-adults (26-50 years) was 3.46 ± 2.1 nmol/L (n= 11) and of senior adults (51-75 years) was 0.23 ± 0.06 nmol/L (n=3). Serum testosterone levels in "non- obedient" elephants ranged from 0.02-11.53 nmol/L while in "obedient" elephants it varied from 0.02-27.33 nmol/L, The mean STL for "non-obedient" elephants was 3.59 ± 1.5 nmol/L (n=9) and in "obedient" elephants it was 4.42 ± 1.5 nmol/L (n=24). One month after the onset of tnusth in a non-obedient male, signs had to be controlled for which, 7 tablets of Flutamide was given daily for 2 weeks. Serum testosterone level was reduced in this animal to 24.76 nmol/L following treatment. A subsequent intramuscular injection of20 mg of Oestradiol benzoate could reduce it further to 9.47 nmol/L. It can be stated that, STL in captive male elephants in Sri Lanka are comparable to published values. The relative increase in STL when approaching musth was anticipated. Inverse relationship between STL and age of the animal was expected. Higher levels of hormone in the morning may indicate that the keeper has to be careful in the morning hours when releasing the animal. In addition, when captive breeding is attempted, morning hours would possibly produce better quality semen. However, male elephants that are known to be "obedient" did not always have low levels STL. Three extremely corporative males had very high level of testosterone indicating the possibility of contribution by other factors for temperament. This finding has immediate use for elephant owners and keepers, for their safety. When keepers are being changed, this factors need to be considered by elephant owners.
Single-phase digital energy meter
(University of Peradeniya, Sri Lanka, 2005-11-10) Sureshkumar, S.; Atputharajah, A.; Wijayakulasooriya, J. V.
It is being well recognized that one of the major reason for electrical energy loss and waste is lack of accountability. In order to properly audit energy consumption in different departments in distributor's and consumer's networks, it is required to monitor power consumption in boundaries. This will demand accurate and cost effective monitoring equipment such as a digital power meter. A PIC based digital energy meter is a good contender for this purpose, with remote metering and web based billing can also be incorporated. The work presented in this paper explains the design and implementation of a single phase digital energy meter, which is having two sensor modules, a data processing module, a user interface and a PC interface. Voltage and current sensors are two separate modules, which sense voltage and current of the main power line. The main power line voltage values are mapped in to an analogue voltage signal with the range of 0-5V. It is assumed that the main supply voltage cannot exceed 240V. So the voltage is stepped down and linearly mapped with 0-5V by the voltage sensor module. One of the key features of this meter design is, facilitating of switched scaling, which was incorporated to increase the accuracy of the meter in current measurement. By and large, in a single phase domestic load, the current is less than 30A. But it may grow up to 50-60A in some sporadic circumstances. Therefore the current sensing module is implemented with two 0-5V output scale circuits, which are mapped with 0-30A and 0-60A of input current ranges. Depending on the transient current value in domestic load, the data processing module automatically selects either one of these current scale circuits. Data processing module consists of a PIC16F877A micro controller, which is fed by sensors with three voltage signals. Input signals are sampled with the built-in NO converters of the PIC and their instantaneous values are driven. To reduce the errors due to the delay in AID conversion, voltage signal is sampled two times before and after the current sampling, and the average voltage is taken for the process. For the current measurement, the output of 0-30A scale circuit is taken as the default. If this value reaches 5V then the 0 - 60A scale circuit is taken as input source. So, this switching of scaled input is automatically done respect to the sensed transient current on main supply. From these instantaneous values all other parameters such as instantaneous power, cumulated energy, power factor, average power, apparent power and the peak values are driven by using several mathematical algorithms. User interface module consists of an LCD to display the parameter and its value according to the user's request. Push buttons help users to select the parameter to be displayed. PC interface is a serial interface with the data processing module, and which is used to calibrate the meter initially and for continuous data monitoring. This research work boosts energy meter technology with the newly added scaling circuitry to increase its accuracy and measurement range.
Socio-economic upliftment of the community around Dambulu-Oya reservoir by applying pri model
(University of Peradeniya, Sri Lanka, 2005-11-10) Edirisinhge, U.; Weerathilake, W. A. D. V.; Ediriweera, E. W. A. C.; Piyarathne, R. S.; Yatapana, Y. T. D.; Kodithuwakku, D.; Athapaththu, A.
Community around Dambulu-oya reservoir lives in three villages. viz Pohoranwewa, Ibbankatuwa and Tennekoonpura. Main livelihood activities in this area are fishing and farming. By identifying Fisheries Co-operative Society as a nucleus, a socio-economic upliftment programme for the sustainable development and management of common pool resources of this community was developed with the assistance of the Regional Economic Advancement Project (REAP), Matale. This programme was implemented by selecting 403 families whose monthly legal income was lower than Rs 6000.00. Using a pre-tested questionnaire, basic data were collected in 2002 (at the inception of the project) and at the end of 2004. Data were analyzed using SPSS package. There is a high contribution from Socio-Economic Upliftment Project for the individual development through training programmes, loans, assisting children's education and motivation and guidance. Identified problems related with farming are market price fluctuation, high cost of agro-chemicals and fertilizers, pests and diseases, financial problems and less availability of lands. In fishing, unavailability of fishing crafts and nets, low fish production and illegal fishing were the major problems. In livestock rearing, diseases, low feed availability, low milk yield and non-availability of suitable animals were the major constraints. The holistic approach of the Participatory Rapid Implementation Model (PRI) developed by Aquatic Resources.Development Project (ADP) has shown to be a success. PRT model is to be applied for socio-economic development of communities in developing countries. This model could be implemented within three months after an initial survey. PRT utilizes all resources in the area by common agreement with all the stakeholders. It tries to utilize different resources of the farmers simultaneously which reduces the risk of failure due to the influence of complementary activities. Socio- economic conditions are at a satisfactory level in this community. As a result of this programme monthly income, percentages of integrated farmers and motivation towards the education of children have improved. Alcoholism has significantly reduced. Co- operative society functions as a bank, and caters to the financial needs of the members.
Sol-gel synthesis of LiCoO₂ and LiCo₀.₄Ni₀.₆O₂, their electrochemical performances and applications in Li-Ion batteries as cathode material
(University of Peradeniya, Sri Lanka, 2005-11-10) Balasooriya, N. W. B.; Bandaranayake, P. W. S. K.
Lithium cobalt oxide (LiCoO₂) is extensively used as a cathode material in commercially available Li-ion batteries due its high energy density and good cycle-life performances. However, the high cost of this material and toxicity of cobalt are some drawbacks. Recently, the cathodes of the type LiMₓNiᵧ0₂ where M is one of the transition or alkaline earth metals are being extensively used as less-costly cathodic material in Li-ion batteries. The aims of the present work are to study the structural and electrochemical properties of LiCoO₂ and lithiated nickel cobalt oxide, LiCo₀.₄Ni₀.₆O₂, and to assess their applications in Li-ion batteries. LiCoO₂ and LiCo₀.₄Ni₀.₆O₂ were synthesized by using the sol-gel technique. The properties of the compounds were studied using XRD, ITIR and DSC. The oxides LiCoO₂ and LiCo₀.₄Ni₀.₆O₂ were used as cathode materials for rechargeable lithium-batteries and their electrochemical performances were studied. The potentiostat and galvanostat techniques were used to determine the electrochemical characteristics. The discharge capacities of the LiCoO₂ were 155 and 145 mA h g⁻¹ of the LiCo₀.₄Ni₀.₆O₂ were 19 and 15 mA h g⁻¹ for the 1st and 15th cycles, respectively. The overall electrochemical capacity of LiCo₀.₄Ni₀.₆O₂ oxide has been drastically reduced due to the s-block or p-block metal substitution and impurity remained during the synthesis and showed very poor cycleability. However, more stable charge-discharge cycling performances have been observed for LiCoO₂ oxide at different current rates. Differences and similarities between these two cathode materials are also discussed. Using the synthesized LiCoO₂ as the cathode and natural untreated vein graphite of Sri Lanka as anode with 1 M LiPF₆ in EC/DMC as liquid electrolyte Li-ion batteries were assembled and tested.
Species composition and abundance of dung beetles in cattle dung
(University of Peradeniya, Sri Lanka, 2005-11-10) Jayasekara, T. N.; Edirisinghe, Jayanthi P.; Karunaratne, W. A. Inoka P.
Dung beetles (Coleoptera:Scarabaeidae:Coprinae) play an important role in the degradation and recycling of dung, specifically of herbivores. In forest ecosystems they play a key role by performing subterranean burial and dispersal of seeds. Dung beetle assemblages comprise of 3 distinct guilds; the dung rollers (telecoprids), dwellers (endocoprids) and tunnelers (paracoprids). The species composition of dung beetles belonging to these 3 guilds varies geographically and in different habitats. Telecoprids collect dung into.balls, roll away from the source and deposit in burrows or tunnels. Dung balls are either fed upon or are used for deposition of eggs and thereafter as a source of food for the emerging larvae. Dung dwellers remain within the dung pat, feeding and breeding in the dung. Tunnelers excavate deep tunnels in the soil underneath dung pats and deposit dung balls in the tunnels on which they feed and breed. This study reports preliminary findings on the species composition of dung beetles, their abundance and colonization in cattle dung pats held in a grassy area of the Peradeniya University Park. Fresh cattle dung pats (I kg) obtained from a near by cattle shed were used in the study. By exposing pats (d = 23.0 em) diurnally (8:00-16:00 h) and nocturnally (18:00-6:00 h), the diel variation in dung beetle colonization was examined. Variation in dung beetle community with time was studied by exposing dung pats for 1-10 days. After the exposure period, dung pats and the soil underneath were removed separately and beetles were extracted using the flotation method. Collected dung beetles were counted and identified using keys and descriptions given in the Fauna of British India, Ceylon and Burma and confirmed by F. Krell, Coleopterist of the Natural History Museum, London. A total of 17 species of dung beetles in 7 genera were recorded. Thirteen species belonged to the endocoprid guild represented by Aphodius sp. 1, 2 land 3, Drepanocerus setosus (Wied.), Onthophagus cervus (F.), 0. cemricornis (F.), 0. pygmaeus Schall., 0. unifasciatus (Schall.), Oidama (F.), 0. turbatus Walk., 0. militaris Bouc., 0. rectecornutus Lansb., 0. gemma Sharp. The three species, Catharsius molossus (L.), Copris signa/US Walk. and Onitis subopacus Arrow. belonged to the paracoprid guild. Only a single species, Sisyphus hirtus Wied. belonging to the telecoprid guild was recorded. The species first to colonize diurnal pats were Onthophagus centricomis. and Onthophagus pygmaeus followed by Sisyphus hirtus, Onthophagus unifasciatus, and Drepanocerous setosus. First to colonize nocturnal pats were Onthophagus cervus and 0. dama followed by Onitis subopacus and Copris signatus. The three species of Aphodius, Catharsius molossus and 0. turbatus colonized both -day and night pats. The highest abundance of dung beetles (Mean 133, Range 66-175) was in day-old pats. The numbers declined almost threefold by day 3 and reached very low numbers by day 5 and thereafter. The hard crust of the pat remained intact for several more days and the underneath was filled with excavated soil.
Spot urinary osmolality : creatinine ratio in healthy humans
(University of Peradeniya, Sri Lanka, 2005-11-10) Kanankearachchi, K. A. P. P.; Godevithanage, S.; Dissanayake, D. M. M. P.; Jayalath, W. A. T. A.; Chandrasiri; Jinasena, P. H. R. P.; Goonasekera, C. D. A.
Spot urine albumin/ creatinine ratio is a reliable estimate of 24-hour urine albumin excretion since it accounts for the variability in urine concentrations over time. Similarly urine osmolaliy: creatinine (Osm/cr) ratio of a spot urine sample may give an overall estimate of urinary excretion of solutes and renal concentrating ability. We have previously presented data to support that urine Osm/cr in healthy adults is a reproducible entity. The objective of this study was to establish influence of age, sex, body weight and height on spot urine Osm/cr ratio in healthy humans. Two hundred and thirty two healthy volunteers participated. They were stratified to 7 age groups (a) 1.5-5 years, (b) > 5-10 years, (c) > 10-20 years, (d) > 20-30 years, (e) > 30 to 45 (f) > 45-60 years, (g) > 60 years. 15 males and 15 females were allocated for each age category. A spot urine sample was collected from all patients and was analyzed for urine osmolality and creatinine in batches of 50. The influence of age, sex, body weight and height on the Osm/cr was analyzed using multiple linear regression and only the height showed significant correlation. [Osm/cr = 265.3 ± 0.9588 (height)] R square was 0.02 suggesting height may make 2 % influence on urine Osm/cr ratio. In conclusion, urine Osm/cre ratio needs no correction for gender, age and body weight.
Steiner triple system in higher order
(University of Peradeniya, Sri Lanka, 2005-11-10) Maheepala, M. M. J. D.; Perera, A. A. I.
Combinatorics could be described as the art of arranging objects according to specified rules. We want to know whether a particular arrangement is possible at all, and if so, the number of ways by which it can be done. If the rules are simple (like picking a cricket team from a class of schoolboys), the existence of an arrangement is clear, and we concentrate on the counting problem. But for more involved rules, it may not be clear whether the arrangement is possible at all, for example, Kirkmans's schoolgirls' problem. The main objective of this project is to construct Steiner Triple System of higher order, which could be used to solve many combinatorics problems. A pair (X, B), where X is an n-set and B is a family of m-subsets of X, such that any l-set lies in almost one member of B is called Steiner system S (l, m, n). S (2, 3, n) is called the Steiner Triple System and is denoted by STS (n). We construct Steiner triple system for higher order n. For these constructions, we use difference sets, block designs, quadratic residues and orbits. Both graphical and recursive construction are given in our work and we have shown that the recursive construction method can be used to construct higher order Steiner Triple Systems.
Student perception of true/false type multiple choice questions (MCQ) as a method of evaluation in forensic medicine
(University of Peradeniya, Sri Lanka, 2005-11-10) Chinthika, H. L. H.; Edussuriya, D. H.; Marambe, K.
Multiple Choice Questions (MCQ) are an important component in the process of evaluation in Forensic Medicine. Compared to evaluation by long essay type questions and viva-voce examinations, MCQ ensure objectivity and are reliable. High quality MCQs conforming to existing guidelines on MCQ construction is a convenient method of assessing all three cognitive levels of knowledge of large numbers of students. Thus medical students' perceptions of the currently used MCQs in Forensic medicine are explored with a view to revising and improving the existing bank. A questionnaire was administered to 174 students of the 2001/2002 batch and 178 Students of the 2000/2001 batch with the intention of documenting students' views on current MCQs. The response rate was 67.89 % (239). Analysis of the responses to the questionnaire revealed that a vast majority (86.06 %) of students perceived MCQs as an important evaluation tool. A majority of students also had no objections to the frequency of the MCQ assessments (82.30 %) or the time allocated per question (82.86 %). The majority endorsed the view that the questions were clinically relevant (68.91 %) and that reading material in addition to the recommended textbooks and lecture notes were needed in answering forensic medicine MCQs (70.90 %). However, it was disturbing to note that a nearly half the number of students have had problems with understanding MCQs (42.86 %). Most students also indicated that the Forensic Medicine MCQs only evaluate recall ability (76.11 %) MCQs would remain a major component in Forensic Medicine examination. Thus a mechanism has to be developed to improve the quality of this evaluation tool.
Study of calcium as a bone marker in gingival crevicular fluid of healthy adolescents with class 1 crowding: a preliminary study
(University of Peradeniya, Sri Lanka, 2005-11-10) Wellappuli, N. C.; Chandrasekera, A.; Kalyanarathne, K. A.; Amarasena, J.; Peiris, B. B. M.
During orthodontic tooth movement, light forces applied to teeth induce resorption of the supporting alveolar bone. These tooth movements can be assessed by using markers of bone turnover around the tooth and, supporting structures such as gingival crevicular fluid (GCF) and alveolar bone surfaces. Evaluation of such bone markers in GCF may be important in assessing the outcome of orthodontic treatment. The aim of this study was to determine whether simple bone markers like calcium, magnesium and alkaline phosphates could be detected in GCF of healthy adolescents with class I crowding. Ten subjects (5 females and 5 males) were selected from successive patients who were referred to the Division of Orthodontics, Dental Hospital (Teaching), Peradeniya prior to commencement of treatment. All subjects had a healthy periodontal status (Gingival index = 0; pocket depth < 3 mm GCF samples were collected from the crevice region of the distal surface of the maxiIIay canines using filter paper strips according to Griffith (1998). After drying and isolating the area concerned, a filter paper strip was placed at the entrance to the gingival crevice for 5 s. After I min,another strip was used to obtain another 5 s sample. This was followed by a 30 s interval and final 30 s collection from both the left and right sides. After removing from the crevice entrance, the filter paper strips were immediately placed in the micro- centrifuge tubes and caps were fitted to prevent evaporation. I The concentration of calcium was estimated using electrode technique. This study revealed that calcium could be detected in GCF of healthy individuals. Mean calcium concentrations of males and females were 1.86 g/dl (SD= ± 3) and 1.61 g/dl (SD = ± 2.9) respectively. There was no significant difference between the two gender groups with regard to the level of calcium (P> 0.05). This study will be continued to ascertain the possibility of detection of other markers and to explore their relationship to different types of orthodontic tooth movements.
Study of rapid rock weathering: a case study from Samanalawewa project, Sri Lanka
(University of Peradeniya, Sri Lanka, 2005-11-10) Udagedara, Tharanga; Gunatilake, Jagath
Rocks utilized for the Samanalawewa Project have undergone severe weathering after excavation. Rocks in the project area have undergone differential weathering and therefore, various weathering grades can be observed in the project area. The rocks used as construction materials, foundation materials and road aggregates suffer this calamity and they became incongruous for the sustainability of the project. Further, the Adit "D" and rip rap zone of the dam are under intimidation owing to this weathering. Eventhough several rock types are utilized for the project, only one rock type has undergone rapid weathering for the last fifteen years. This rock type is identified as garnet sillimanite gneiss. Once water interacts with the particular rock, water becomes acidic with time and this acidity causes rock weathering. This process is called acid hydrolysis. In order to generate such acidic nature, sulphuric acid forms during the rock water interaction. In reality, the acidity is the consequence of the dissolution of pyrite (FeS₂) in water. It is a complex series of chemical weathering reactions which are spontaneously initiated under an oxidizing environment. The reactions are analogous to "geologic weathering" which take place over extended periods of time, but the rates of reaction are orders of magnitude greater than in "natural" weathering systems. The accelerated reaction rates can release damaging quantities of acids, metal ions and other soluble components into the environment. Spatial distribution of the pyrite is imperative, when the rock contains extra quantity of pyrite, low pH results. Therefore, different grades of weathered rock exist in the quarry site, along the adit and within the dam. In this particular case, geological structures also play an important role. To facilitate water movement, permeability of the rock is crucial. The permeability is a consequence of the micro-fractures in the rock produced, either by brittle deformation or during and after blasting. Eventhough the reaction initiates under oxidizing environment, it then proceeds without oxygen, hence once the reaction commences it will continue even under reducing environment. With the intention of preventing the rock from further weathering, the weathered part should be removed and then oxidizing environment should be deactivated.

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