477 research outputs found
Closed-Form Solutions of Zero Dimensional -Field Theory Using Bessel Functions: A Non-Perturbative Approach
The integral is used as an
introductory learning tool in the study of Quantum Field Theory and path
integrals. Typically it is analysed via perturbation theory. Close form
solutions have been quoted but it is not clear how they were derived. So I set
about deriving the close form solution on my own and using the same methodology
obtain closed form expressions for the even positive integer moments.Comment: 6 page
Morphotypes of Phytoliths in Selected Traditional Rice Landraces
Rice (Oryza sativa), belong to family Poaceae can absorb Silica from the soil solution to the plant structure in the form of monosilicic acid (H4SiO4) via the silica transporters available in plasma membrane of root cells thus forming amorphous structures known as phytoliths. Among the diverse morphotypes of phytoliths available in Sri Lankan traditional rice varieties, abundant number of bilobate, rectangular and bulliform phytolith shapes could be observed. The major objective of this study is to determine the statistical relationship of selected three phytolith types; bilobate, rectangular and bulliform shapes in thirteen selected Sri Lankan traditional rice varieties and to determine the statistical variations among them. Dry Ashing method was used to extract phytoliths from dried leaf samples of selected Sri Lankan traditional rice varieties and the specimens were observed using B350 OPTIKA microscope. The dimensions of each phytolith morphotype; length: breadth of bilobate shape, length: height and width of the base of bulliform shape and length: breadth of rectangular shape were measured. Phytoliths of selected Sri Lankan traditional rice varieties showed different sizes among selected varieties and the statistical analysis showed lowest and highest length to breadth ratio in Herath Banda and Sulai varieties respectively in which Herath Banda variety does not exceed the ratio value 2 while other selected Sri Lankan traditional rice varieties exceed the ratio value 2 showing elongated bilobate shapes. A considerable variation of length: breadth ratio of rectangular shape phytoliths is shown by Kahawanu variety in which the ratio exceeds 1.25 whereas all other rectangular phytoliths of selected varieties are below 1.20 ratio value. Length: width of the base and height: width of the base ratios of bulliform phytoliths show similar distribution of each selected variety but, length: height ratios show variations in which Kalu Heenati exceeds the ratio value 1 while all the other varieties are below the ratio value 1. Comparison of the ratio values of phytolith types of selected Sri Lankan traditional rice varieties show the size variations of the same phytolith type among traditional rice varieties of the same species. These statistical variations could be used for the identification of fossilised phytoliths of rice varieties used in ancient history of human civilisation.Keywords: Phytoliths, Morphotypes, Bilobate, Bullifor
PRESCHOOL TEACHERSâ CONCERNS ON EDUCATIONAL THEORIES AND VIEWS OF EDUCATIONISTS TO DEVELOP CREATIVITY IN THE TEACHING- LEARNING PROCESS
The global attention on research in preschool education has increased and there is an immense motivation in the field of research in Sri Lanka. This research shows that the preschool education is a critical way to introduce and develop all aspects of a childâs development with a focus on creativity. The mixed method design approach was used in this research and a stratified random sample was used to collect data during 2015 and 2016. Questionnaires, Interviews and observations were used to collect data from the selected preschools in the Colombo district, Sri Lanka. Descriptive statistics were used for data analysis.The findings showed that the majority of preschools are run by Non- Government organizations, and the State does operate some preschools. Most of the preschool teachers of Government and Non- Government preschools were not aware of creativity as a learning concept. It was observed that teachers use several methods that did not promote creativity. Preschool teachers mostly provided instructions while trying to keep children quiet in order to manage the classroom. The majority of preschool teachers stated that they faced problems in preparing lessons to develop childrenâs creativity. In conclusion, it showed that preschool teachers do not have adequate training and knowledge regarding the importance of creativity and its implications for the education of children.Findings of this research are expected to be shared with relevant authorities in order to improve teacher training, curriculum development and further research on preschool education
Utilization of aquatic plants: a method to enhance the productivity of water in seasonal tanks in the Anuradhapura District
Heavy infestations of aquatic plants in a water body cause considerable economic and ecological losses. Many seasonal tanks in the Anuradhapura District suffer from this problem and cannot be neglected in water resource development and management schemes. This study was focused on the uses of aquatic plants and the problems caused by huge manifestations of aquatic plants in the selected seasonal tanks in the Anuradhapura District. The study was conducted in four seasonal tanks viz., Galkulama, Thirappane Maradankadawala and Thibbatuwewa in the Anuradhapura District. Information on the utilization of aquatic plants, exploitation level and harmful effects were gathered by using a structured questionnaire to interview people who were residing close to the study sites. The attitudes of the public towards the aquatic plants i.e., conservation of aquatic plants, the potential uses of native plants and harmful effects of invasive aquatic plants were collected. Twelve species were identified as economically important aquatic plants through the questionnaire survey. Among the 50 respondents, 92 % utilized aquatic plants for food, 58 % utilized flowers for offerings and decorations, 52 % utilized aquatic plants for medicinal purposes, 42 % utilized them as ornamental plants, 30 % used them as bio-fertilizers and 28 % utilized them for weaving. The edible aquatic plants consumed by the rural community in the Anuradhapura District are Ipomoea aquatica (72 %), Alternanthera sessilis (66 %), Nelumbo nucifera (64 %), Nymphaea pubescens (60 %) and Aponogeton spp. (52 %). Some edible aquatic plants, namely Neptunia oleracea, Ottelia alismoides and Ceratopteris thalictriodes, which are present in the Anuradhapura District, are not consumed, although these are consumed in many other countries. N. nucifera is the most commonly used flower for offerings in the temples and for decorations. In addition, N. pubescens, Nymphaea nouchali are also used for flowers. Bacopa monnieri, N. nucifera, Acanthus illicifolia, N. nouchali and Aponogeton spp. have been recorded as medicinally important plants. Though there are many ornamentally important aquatic plants, only N. pubescens, N. nouchali, B. monnieri, Nymphoides hydrophylla are used. Salvinia molesta and Eichhornia crassipes are the two aquatic plants commonly used as bio fertilizers. With reference to the questionnaire survey, there were seven major problems that were discovered to exist due to heavy infestations of aquatic weeds in the water bodies viz., sedimentation and unsuitability for domestic use, interference with navigation, effects on fisheries, blocking irrigation canals and evapotranspiration. The most problematic plants in the Anuradhapura District include E. crassipes, N. nucifera, S. molesta, Pistia stratiotes and Ceratophyllum demersum. Economically important aquatic plants available in the shallow water bodies of the Anuradhapura District, are marginally utilized, when compared with the utilization of aquatic plants in the global scenario. There appears to be a lack of a well organized action plan to cope with this situation. The public suffer a lot from the problems created by the heavy mass of aquatic plants, which covered the village tanks. The public are, however, willing to get organized and to engage in a participatory approach to restore their water bodies. There is a need for research and development of management strategies for the sustainable utilization of these valuable resources. Awareness programs should be conducted to promote sustainable utilization of aquatic plants. Creating awareness among the people about the nutritional and economic benefits of these natural resources will be useful for Sri Lanka, as a developing nation.Length: pp.23-32Aquatic plantsTanks
Seed dormancy and germination in three annual canarygrass (Phalaris canariensis L.) cultivars relative to spring wheat (Triticum aestivum L.)
Non-Peer ReviewedSeed dormancy in annual canarygrass may lead to unsatisfactory germination in seed tests. The objectives of this study were (i) to quantify the levels of seed dormancy in three morphologically diverse annual canarygrass cultivars (âKeetâ, âCDC Mariaâ, & âCY 184â) relative to spring wheat & (ii) to determine the effectiveness of three treatments (GA3, KNO3, & chilling) & two temperature regimes (15/25°C & 15°C) in promoting germination of dormant annual canarygrass seeds. The hard red spring wheat cultivar âKatepwaâ control was included as a representative of a cereal crop that has been extensively characterized with regards to seed dormancy. In 1998 & 1999, the four cultivars were grown at Saskatoon, Canada. At maturity, panicles & spikes were hand harvested & stored at â20°C. Four replications of 50 seeds per cultivar were used in each experiment. Three experiments were conducted: (i) seeds were germinated at 10, 15, 20, & 25°C for one week, (ii) seeds were stored at 24°C for zero to eight weeks prior to germination at 22°C for one week, & (iii) seeds were treated with GA3, KNO3, & chilling prior to germination at 15/25°C (16/8h) or 15°C for two weeks. For experiment one & three, a split-plot analysis was used to analyze arc sin transformed percentage germination data. Average percentage germination data in experiment two were tested to be significantly different from 98% germination (P=0.05) based on one-tailed t-tests. Annual canarygrass developed deeper dormancy than the wheat cultivar in both years, particularly when germinated at 20 & 25°C. The highest percentage germination was observed at 15°C. Two (1998) & four weeks (1999) of storage at 24°C were required to overcome dormancy in annual canarygrass. Pre-chilling or KNO3 treatment prior to germination at 15/25°C (16/8h in darkness) resulted in average germination levels of 94% (1998) & 66% (1999). Potassium nitrate treatment prior to incubation at 15°C in darkness was the most effective method of promoting germination in dormant seeds, resulting in 99% (1998) & 97%
(1999) germination. Thus, we recommend the use of the latter method, instead of the former or currently recommended method (pre-chilling or KNO3 treatment prior to germination at 15/25°C [16/8h] in darkness), for testing germination levels of dormant seed of annual canarygrass
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Impact of laparoscopic versus open surgery on hospital costs for colon cancer: a population-based retrospective cohort study
OBJECTIVE: Laparoscopy is increasingly being used as an alternative to open surgery in the treatment of patients with colon cancer. The study objective is to estimate the difference in hospital costs between laparoscopic and open colon cancer surgery.
DESIGN: Population-based retrospective cohort study.
SETTINGS: All acute hospitals of the National Health System in England.
POPULATION: A total of 55â
358 patients aged 30 and over with a primary diagnosis of colon cancer admitted for planned (elective) open or laparoscopic major resection between April 2006 and March 2013.
PRIMARY OUTCOMES: Inpatient hospital costs during index admission and after 30 and 90â
days following the index admission.
RESULTS: Propensity score matching was used to create comparable exposed and control groups. The hospital cost of an index admission was estimated to be ÂŁ1933 (95% CI 1834 to 2027; p<0.01) lower among patients who underwent laparoscopic resection. After including the first unplanned readmission following index admission, laparoscopy was ÂŁ2107 (95% CI 2000 to 2215; p<0.01) less expensive at 30â
days and ÂŁ2202 (95% CI 2092 to 2316; p<0.01) less expensive at 90â
days. The difference in cost was explained by shorter hospital stay and lower readmission rates in patients undergoing minimal access surgery. The use of laparoscopic colon cancer surgery increased 4-fold between 2006 and 2012 resulting in a total cost saving in excess of ÂŁ29.3 million for the National Health Service (NHS).
CONCLUSIONS: Laparoscopy is associated with lower hospital costs than open surgery in elective patients with colon cancer suitable for both interventions
3-D Printed Strain Sensor for Structural Health Monitoring
Additive manufacturing, or 3D printing, is evolving from a technology that can only aid rapid prototyping, to one that can be used to directly manufacture large-scale, real-world equipment. Gravity Separation Spirals (GSS) are vital to the mining industry for separating mineral-rich slurry into its different density components. In order to overcome inherent drawbacks of the traditional mould base manufacturing methods, including significant tooling costs, limited customisation and worker exposure to hazardous materials, a 3D printer is under development to directly print spirals. By embedding small Internet of Things (IoT) sensors inside the GSS, it is possible to remotely determine the operation conditions, predict faults, and use collected data to optimise production output. This work presents a 3D printed strain sensor, which can be directly printed into the GSS. This approach uses a carbon-based conductive filament to print a strain gauge on top of a Polylactic Acid (PLA) base material. Printed sensors have been tested using an Instron E10000 testing machine with an optical extensometer to improve accuracy. Testing was conducted by both loading and unloading conditions to understand the effect of hysteresis. Test results show a near-linear relationship between strain and measured resistance, and show a 6.05% increase in resistance after the test, which indicates minor hysteresis. Moreover, the impact of viscoelastic behaviour is identified, where the resistance response lags the strain. Results from both conductive and non-conductive material show the impact of the conductive carbon upon the tensile strength, which will help to inform future decisions about sensor placement
Environmental Performance of Backyard Poultry Production System in Sri Lanka
Livestock production systems exert severe negative impacts on environment. In the light of projected increase in livestock product consumption, production systems that exert lower environmental impacts are to be identified and promoted. Despite the recent popularity of intensive poultry production systems, backyard poultry production systems (BY) still play an important role in socio-economic fabric of rural communities. However, environmental performance of BY are less documented. Objective of this study was to ascertain environmental performance of BY in Sri Lanka. Two hundred and ninety five backyard poultry farms in ten districts of six provinces were selected using three stage random sampling technique (provinces, districts and farms). Production performance and information related to spent litter disposal practices, the level of dust emission, presence of mal-odour and phenotypical characters of the flocks were collected. Based on an emission factor reported in literature, ammonia emission was estimated to as high as 21 g of NH3 N per dozen of eggs. Emission rate was significantly higher for those who considered backyard poultry keeping a hobby than those who considered it an additional income source or the main income source. Emission rate was significantly lower when purchased supplemental feeds were given than when not (18 and 22 g NH3 N/dozen egg, respectively). Ammonia smell was felt just outside the pens of the 60% of the farms. Risk of polluting water resources was found to be high in 28% of farms which used to dump spent litter indiscriminately. Dust emission was judged at a problematic level in 46% of the poultry houses, among them 73% considered backyard poultry an additional income source. Flocks in 94% farms were comprised of genetically non-descriptive birds of numerous crosses. NH3 smell was felt at 12% the houses which practice backyard poultry production. However, only a 50% of them admitted that they normally sense ammonia smell at their houses. BY was identified as an important mean of conserving livestock biodiversity. Environmental performance parameters such as ammonia emission, risk of polluting water resources and dust emission of BY were concluded to be weak.Keywords: Ammonia, Backyard, Dust, Environment, Poultr
Impact of Destination Attributes on Tourists Destination Selection: With Special Reference to Cultural Triangle of Sri Lanka
Sri Lanka is one of the fastest-growing tourist destinations in the world. Amongst touristsâattractions, âCultural Triangleâ, a region of the cultural heritage of the country has becomethe highest income generating destination. However, when compared with the othertouristsâ destinations of the country, the number of tourists visiting the cultural triangle islow. As the literature reveals, the attributes of the destination matter in destinationselection by the international tourists. Thus, considering the importance of this region asthe top income contributor but not in terms of the number of tourists' visits, this studyproblematizes the impacts of destination attributes on tourist`s destination selection.Accordingly, the objective of this study is to identify the destination attributes and theirrelationship with the touristsâ destination selection decisions. Data was collected throughquestionnaires from a sample of 222 foreign tourists who visited the cultural triangleduring 2019 through a selected travel agent. Results of the multiple regression analysisrevealed that attributes of Amenities, Destination Attractions, Accessibility, AncillaryServices, and Destination Environment as having a moderate positive relationship whilst,the service quality weak positive relationship with Touristâs Destination selection.Destination attraction was identified as the most influential factor of all attributes. Thefindings of this study can be used by policymakers in developing destinations for touristsâattractions in the country
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