Pub Date : 2024-04-09DOI: 10.4038/jnsfsr.v52i1.11647
K. Deshani, D.T. Attygalle, L.L. Hansen
With the advancement of technology, time series data are automatically collected without human intervention. As the data collection process becomes effortless, the next change encountered is to identify the best method to forecast time series data with high accuracies. In this regard, hybrid approaches have gained much attention where the strengths of two approaches can be combined to lessen the weaknesses of each individual approach. When exploring the features of time series data, some depict repetitive patterns and also data can be observed at several levels. The repeating curves can be considered as the higher level, whereas each individual observation can be considered as the lower level. Thus, in order to handle the data in a more effective way, the series can be handled at two levels by giving prominence to the features of each level separately. This paper proposes a novel algorithm named two level neuro-functional forecaster, which is capable of handling data at two levels, hybridizing a statistical approach with an artificial intelligence approach, to gain high accuracy levels. In addition, as this approach handles data at two levels, data sparsity at a particular level can be accommodated at the other level. To apply this algorithm to a real world dataset, electricity demand data in Sri Lanka was considered where the series consisted of daily load curves with repetitive pattern across the days. The proposed hybrid algorithm, outperforms the two approaches when individually used, with a MAPE of 3.324% for a year.
{"title":"Two level neuro-functional forecaster: A novel dynamic hybridization for functional data forecasting","authors":"K. Deshani, D.T. Attygalle, L.L. Hansen","doi":"10.4038/jnsfsr.v52i1.11647","DOIUrl":"https://doi.org/10.4038/jnsfsr.v52i1.11647","url":null,"abstract":"With the advancement of technology, time series data are automatically collected without human intervention. As the data collection process becomes effortless, the next change encountered is to identify the best method to forecast time series data with high accuracies. In this regard, hybrid approaches have gained much attention where the strengths of two approaches can be combined to lessen the weaknesses of each individual approach. When exploring the features of time series data, some depict repetitive patterns and also data can be observed at several levels. The repeating curves can be considered as the higher level, whereas each individual observation can be considered as the lower level. Thus, in order to handle the data in a more effective way, the series can be handled at two levels by giving prominence to the features of each level separately. This paper proposes a novel algorithm named two level neuro-functional forecaster, which is capable of handling data at two levels, hybridizing a statistical approach with an artificial intelligence approach, to gain high accuracy levels. In addition, as this approach handles data at two levels, data sparsity at a particular level can be accommodated at the other level. To apply this algorithm to a real world dataset, electricity demand data in Sri Lanka was considered where the series consisted of daily load curves with repetitive pattern across the days. The proposed hybrid algorithm, outperforms the two approaches when individually used, with a MAPE of 3.324% for a year.","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140721052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-09DOI: 10.4038/jnsfsr.v52i1.11460
N. Alkan, M.C. Pardo, B.B. Alkan
The Cox regression analysis is used to determine the relationship between a dependent variable and covariates in survival analysis involving censored data. The proportional hazards assumption is one of the most important assumptions of Cox regression. Outliers may have a strong influence on the Cox regression model’s parameter estimates and lead to violation of the proportional hazard assumption. Therefore, having outliers in the data set is a problem for researchers. In this case, robust estimations are commonly used to infer the parameters in a more robust way. However, we explore a new approach consisting of considering an outlier as missing data and replacing it by the multiple imputation method. The aim of this study is to compare these two methods through simulation. Furthermore, an analysis of a lung cancer data set is considered for illustration. According to the results of the study carried out based on simulated data sets and a real data set, the multiple imputation method, which is a missing data analysis method, solves the problem of outliers better than the robust estimation method, as the outcome is closer to the results obtained through original data.
{"title":"Comparison of methods for handling outliers in Cox regression model","authors":"N. Alkan, M.C. Pardo, B.B. Alkan","doi":"10.4038/jnsfsr.v52i1.11460","DOIUrl":"https://doi.org/10.4038/jnsfsr.v52i1.11460","url":null,"abstract":"The Cox regression analysis is used to determine the relationship between a dependent variable and covariates in survival analysis involving censored data. The proportional hazards assumption is one of the most important assumptions of Cox regression. Outliers may have a strong influence on the Cox regression model’s parameter estimates and lead to violation of the proportional hazard assumption. Therefore, having outliers in the data set is a problem for researchers. In this case, robust estimations are commonly used to infer the parameters in a more robust way. However, we explore a new approach consisting of considering an outlier as missing data and replacing it by the multiple imputation method. The aim of this study is to compare these two methods through simulation. Furthermore, an analysis of a lung cancer data set is considered for illustration. According to the results of the study carried out based on simulated data sets and a real data set, the multiple imputation method, which is a missing data analysis method, solves the problem of outliers better than the robust estimation method, as the outcome is closer to the results obtained through original data.","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140725546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-09DOI: 10.4038/jnsfsr.v52i1.12015
C. Jayawardene, W. Navaratna, J. Senadheera
A new area of Graph theory emerged in the last few decades is the calculation of Star critical Ramsey numbers related to different classes of graphs. Formally, we will say that Kn → (G,H) if given any coloring of Kn there is a copy of G in the first color, red, or a copy of H in the second color, blue. The Ramsey number r(G,H) is defined as the smallest positive integer n such that Kn → (G,H). A closely related concept of Ramsey number is the Star critical Ramsey number r∗(G,H) defined as the largest value of k such that Kr(G,H)−1 ⊔ K1,k → (G,H). A two-coloring of Kr(G,H)−1 such that Kr(G,H)−1 ̸→ (G,H) is called a Ramsey critical coloring. A Ramsey critical r(G,H) graph is a graph induced by the first color of a Ramsey critical coloring. Lower bounds for Star critical Ramsey numbers are usually found with the aid on Ramsey critical graphs. The particular problem we handle in this paper, on Star critical Ramsey numbers, is based on a conjecture posed in 1973 by Bondy and Erdos relating to Ramsey numbers for large cycles versus complete graphs. Based on certain lemmas we present with proof, furthermore we show that there exist exactly sixty eight non-isomorphic Ramsey critical r(Cn,K6) graphs, when n ≥ 15
{"title":"All Ramsey critical graphs for large cycles vs a complete graph of order six","authors":"C. Jayawardene, W. Navaratna, J. Senadheera","doi":"10.4038/jnsfsr.v52i1.12015","DOIUrl":"https://doi.org/10.4038/jnsfsr.v52i1.12015","url":null,"abstract":"A new area of Graph theory emerged in the last few decades is the calculation of Star critical Ramsey numbers related to different classes of graphs. Formally, we will say that Kn → (G,H) if given any coloring of Kn there is a copy of G in the first color, red, or a copy of H in the second color, blue. The Ramsey number r(G,H) is defined as the smallest positive integer n such that Kn → (G,H). A closely related concept of Ramsey number is the Star critical Ramsey number r∗(G,H) defined as the largest value of k such that Kr(G,H)−1 ⊔ K1,k → (G,H). A two-coloring of Kr(G,H)−1 such that Kr(G,H)−1 ̸→ (G,H) is called a Ramsey critical coloring. A Ramsey critical r(G,H) graph is a graph induced by the first color of a Ramsey critical coloring. Lower bounds for Star critical Ramsey numbers are usually found with the aid on Ramsey critical graphs. The particular problem we handle in this paper, on Star critical Ramsey numbers, is based on a conjecture posed in 1973 by Bondy and Erdos relating to Ramsey numbers for large cycles versus complete graphs. Based on certain lemmas we present with proof, furthermore we show that there exist exactly sixty eight non-isomorphic Ramsey critical r(Cn,K6) graphs, when n ≥ 15","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140726548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-02DOI: 10.4038/jnsfsr.v51i4.11473
N. Batapola, N. Dushyantha, N. Ratnayake, H. Premasiri, H. Panagoda, C. Jayawardena, R. Chandrajith, I. Ilankoon, L. Rohitha, A. Ratnayake, J. Koongolla, A. Abeysinghe, D. Dissanayake, R. Ratnayake
The Eppawala area in Sri Lanka has an agricultural-based economy. As a result, the recent agricultural intensification could increase the risk of heavy metal contamination in lakes in the area as the main water canal in the area, i.e., Jaya Ganga, flows across these lakes. Therefore, this study focuses on the risk assessment of heavy metals in the freshwater lake sediments in the Eppawala area and the identification of potential sources for heavy metal contamination in the lakes. Nine heavy metals (Cr, Mn, Co, Ni, Cu, Zn, As, Cd, and Pb) were investigated in surface sediments (n = 22) of the upstream and downstream lakes of the Eppawala Phosphate Deposit (EPD). The average heavy metal concentrations in the upstream lake sediments were higher than those downstream. Eppawala lake sediments were heavily polluted by As along with moderate to high Cr pollution. However, only As and Cd indicated considerable to moderate ecological risk levels to the local environment. The downstream lake sediments showed lower heavy metal contents compared to those upstream and had negative correlations between heavy metals and P2O5 contents. This reveals that the EPD does not contribute to the heavy metal contamination in the Eppawala lake sediments. However, the statistical analysis showed that heavy metals were mostly derived from similar pollution sources. Agrochemicals used in paddy cultivation in the vicinity might be a potential source of heavy metals. This study highlights the importance of implementing remediation to control the heavy metal pollution prevailing in the Eppawala lakes.
{"title":"Risk assessment of heavy metals in the freshwater lake sediments around Eppawala phosphate deposit, Sri Lanka","authors":"N. Batapola, N. Dushyantha, N. Ratnayake, H. Premasiri, H. Panagoda, C. Jayawardena, R. Chandrajith, I. Ilankoon, L. Rohitha, A. Ratnayake, J. Koongolla, A. Abeysinghe, D. Dissanayake, R. Ratnayake","doi":"10.4038/jnsfsr.v51i4.11473","DOIUrl":"https://doi.org/10.4038/jnsfsr.v51i4.11473","url":null,"abstract":"The Eppawala area in Sri Lanka has an agricultural-based economy. As a result, the recent agricultural intensification could increase the risk of heavy metal contamination in lakes in the area as the main water canal in the area, i.e., Jaya Ganga, flows across these lakes. Therefore, this study focuses on the risk assessment of heavy metals in the freshwater lake sediments in the Eppawala area and the identification of potential sources for heavy metal contamination in the lakes. Nine heavy metals (Cr, Mn, Co, Ni, Cu, Zn, As, Cd, and Pb) were investigated in surface sediments (n = 22) of the upstream and downstream lakes of the Eppawala Phosphate Deposit (EPD). The average heavy metal concentrations in the upstream lake sediments were higher than those downstream. Eppawala lake sediments were heavily polluted by As along with moderate to high Cr pollution. However, only As and Cd indicated considerable to moderate ecological risk levels to the local environment. The downstream lake sediments showed lower heavy metal contents compared to those upstream and had negative correlations between heavy metals and P2O5 contents. This reveals that the EPD does not contribute to the heavy metal contamination in the Eppawala lake sediments. However, the statistical analysis showed that heavy metals were mostly derived from similar pollution sources. Agrochemicals used in paddy cultivation in the vicinity might be a potential source of heavy metals. This study highlights the importance of implementing remediation to control the heavy metal pollution prevailing in the Eppawala lakes. ","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139453212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-02DOI: 10.4038/jnsfsr.v51i4.11558
N.M. De Alwis, N. Withanage, C.L. Jayasinghe, S. Ananda
Human Immunodeficiency Virus (HIV) case reporting usually represents only the trending pattern of HIV infected people in Sri Lanka. Having a decent level of knowledge about HIV largely contributes to preventing HIV prevalence in the country. People with HIV are not hazardous to the public who live together with them and with whom they have ordinary, non-sexual contact. However, suffering from HIV in a culture like Sri Lanka generates an extreme level of stigmatizing by people living with HIV and many psychological and social effects. This study aims to identify the factors that are associated with possessing knowledge, among ever married women in the reproductive age in Sri Lanka, regarding two prominent misbeliefs on HIV/AIDS transmission. This will be useful to identify various socio-economic, geographic subgroups who are lacking knowledge on HIV/AIDS spread. Secondary data from 2016 Sri Lanka Demographic and Health Survey was used in the analysis. Joint modelling was considered since it was found that two outcome variables are highly associated and hence the ever-married woman who believes one misconception is more likely to believe the second misconception too. To capture the association between two outcomes, we incorporated a shared random effect and assumed the bridge distribution for the random effect. Respondent’s province, highest level of education, access to mass media, religion, age and wealth index were found to have a significant effect on prominent misconceptions on HIV/AIDS transmission.
{"title":"Socio-demographic and behavioural factors associated with prominent misconceptions of HIV/AIDS transmission among ever married women in Sri Lanka: An application of modelling correlated binary outcomes using a bridge distribution function","authors":"N.M. De Alwis, N. Withanage, C.L. Jayasinghe, S. Ananda","doi":"10.4038/jnsfsr.v51i4.11558","DOIUrl":"https://doi.org/10.4038/jnsfsr.v51i4.11558","url":null,"abstract":"Human Immunodeficiency Virus (HIV) case reporting usually represents only the trending pattern of HIV infected people in Sri Lanka. Having a decent level of knowledge about HIV largely contributes to preventing HIV prevalence in the country. People with HIV are not hazardous to the public who live together with them and with whom they have ordinary, non-sexual contact. However, suffering from HIV in a culture like Sri Lanka generates an extreme level of stigmatizing by people living with HIV and many psychological and social effects. This study aims to identify the factors that are associated with possessing knowledge, among ever married women in the reproductive age in Sri Lanka, regarding two prominent misbeliefs on HIV/AIDS transmission. This will be useful to identify various socio-economic, geographic subgroups who are lacking knowledge on HIV/AIDS spread. Secondary data from 2016 Sri Lanka Demographic and Health Survey was used in the analysis. Joint modelling was considered since it was found that two outcome variables are highly associated and hence the ever-married woman who believes one misconception is more likely to believe the second misconception too. To capture the association between two outcomes, we incorporated a shared random effect and assumed the bridge distribution for the random effect. Respondent’s province, highest level of education, access to mass media, religion, age and wealth index were found to have a significant effect on prominent misconceptions on HIV/AIDS transmission. ","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139453058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-02DOI: 10.4038/jnsfsr.v51i4.11286
S.K. Madarasinghe, K.K.A.S. Yapa, P.M.P. Udayakantha, B. Satyanarayana
Through the years, the green cover has been substantially reduced and transformed into human development projects and settlements in many cities of Sri Lanka. Hambantota, a southern coastal district, has faced similar changes over the last two decades. Therefore, this study was aimed at the Land-Use and Land-Cover (LULC) changes which had taken place along its coastal belt during the period, 1996–2017. Comparison was done among LULC maps bearing fourteen different classes for the years 1996 and 2017. The results reveal that all LULC classes except coconut plantations and paddy lands show significant area changes (p < 0.05) during the period considered. Among the LULC changes, forest cover showed the highest area change (2341 ha loss (p < 0.05)) while 358 ha of scrubland has been cleared to establish housing schemes. The settlements have significantly increased (1318 ha) and a considerable amount is due to development projects including the Hambantota port. The survey results show that 63.9% of the residents in the study area agreed that the natural environment of the city had been affected by the development projects. Analysis of LULC changes and Normalized Difference Vegetation Index (NDVI) data suggests that Hambantota coastal area has developed significantly at the cost of forests and associated vegetation from 1996 to 2017. Rapid economic and population growths are identified as the main driving forces for the LULC changes. These results deliver an important decision-making reference for LULC planning and sustainable development in the Hambantota coastal region, which is, in broad sense, valid for any booming city in the country and the world. The urban forestry concept can be an ideal sustainable move to compensate the green cover loss.
{"title":"Land-use and land cover changes along the coastal belt of Hambantota district, southern Sri Lanka, over the period 1996- 2017","authors":"S.K. Madarasinghe, K.K.A.S. Yapa, P.M.P. Udayakantha, B. Satyanarayana","doi":"10.4038/jnsfsr.v51i4.11286","DOIUrl":"https://doi.org/10.4038/jnsfsr.v51i4.11286","url":null,"abstract":"Through the years, the green cover has been substantially reduced and transformed into human development projects and settlements in many cities of Sri Lanka. Hambantota, a southern coastal district, has faced similar changes over the last two decades. Therefore, this study was aimed at the Land-Use and Land-Cover (LULC) changes which had taken place along its coastal belt during the period, 1996–2017. Comparison was done among LULC maps bearing fourteen different classes for the years 1996 and 2017. The results reveal that all LULC classes except coconut plantations and paddy lands show significant area changes (p < 0.05) during the period considered. Among the LULC changes, forest cover showed the highest area change (2341 ha loss (p < 0.05)) while 358 ha of scrubland has been cleared to establish housing schemes. The settlements have significantly increased (1318 ha) and a considerable amount is due to development projects including the Hambantota port. The survey results show that 63.9% of the residents in the study area agreed that the natural environment of the city had been affected by the development projects. Analysis of LULC changes and Normalized Difference Vegetation Index (NDVI) data suggests that Hambantota coastal area has developed significantly at the cost of forests and associated vegetation from 1996 to 2017. Rapid economic and population growths are identified as the main driving forces for the LULC changes. These results deliver an important decision-making reference for LULC planning and sustainable development in the Hambantota coastal region, which is, in broad sense, valid for any booming city in the country and the world. The urban forestry concept can be an ideal sustainable move to compensate the green cover loss.","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139453146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-02DOI: 10.4038/jnsfsr.v51i4.11429
K. T. Premakantha, R.P.D.S. Chandani, G.G.J.R. Silva, R.P.S.I.K. Gunatilaka, D.K.N.G. Pushpakumara
Trees are found in various formations, ranging from individual trees to randomly occurring tree clusters and systematically established tree plantations, as well as natural forests. Accurate information about trees, their distribution and density is crucial for the development of national policies, strategies, and management decisions related to tree planting, and environmental management. While some organizations and individuals have mapped forests, home gardens, and trees outside forests at different scales, the lack of comprehensive and systematic spatial distribution data on trees and tree cover density in Sri Lanka has been a significant challenge for policymakers. To address this issue, this study utilized the tree cover mapping (TCM) tool developed by U.S. Geological Survey. High-resolution images were visually interpreted within a geographic information system interface to map tree cover. The TCM tool employed a systematic sample grid, with a sampling interval of 200 m. The study encompassed 1.64 million sampling units, and mapping and interpretation were conducted at a scale of 1:3000. The resulting tree density map had a resolution of 200 m. Results show that 78% of the country’s land area has a tree cover density exceeding 10%, resembling open and sparse forests, while 64% of the country exhibits a tree cover density exceeding 40%, comparable to dense forest areas. The study found that although forest cover was limited in districts such as Colombo, Gampaha, and Jaffna, these areas still displayed a significant level of tree cover density, offering services and functions similar to those provided by forests.
{"title":"Assessment of tree cover density of Sri Lanka using visual interpretation of open-source high-resolution imagery and geographic information system interface mapping","authors":"K. T. Premakantha, R.P.D.S. Chandani, G.G.J.R. Silva, R.P.S.I.K. Gunatilaka, D.K.N.G. Pushpakumara","doi":"10.4038/jnsfsr.v51i4.11429","DOIUrl":"https://doi.org/10.4038/jnsfsr.v51i4.11429","url":null,"abstract":"Trees are found in various formations, ranging from individual trees to randomly occurring tree clusters and systematically established tree plantations, as well as natural forests. Accurate information about trees, their distribution and density is crucial for the development of national policies, strategies, and management decisions related to tree planting, and environmental management. While some organizations and individuals have mapped forests, home gardens, and trees outside forests at different scales, the lack of comprehensive and systematic spatial distribution data on trees and tree cover density in Sri Lanka has been a significant challenge for policymakers. To address this issue, this study utilized the tree cover mapping (TCM) tool developed by U.S. Geological Survey. High-resolution images were visually interpreted within a geographic information system interface to map tree cover. The TCM tool employed a systematic sample grid, with a sampling interval of 200 m. The study encompassed 1.64 million sampling units, and mapping and interpretation were conducted at a scale of 1:3000. The resulting tree density map had a resolution of 200 m. Results show that 78% of the country’s land area has a tree cover density exceeding 10%, resembling open and sparse forests, while 64% of the country exhibits a tree cover density exceeding 40%, comparable to dense forest areas. The study found that although forest cover was limited in districts such as Colombo, Gampaha, and Jaffna, these areas still displayed a significant level of tree cover density, offering services and functions similar to those provided by forests.","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139453492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-02DOI: 10.4038/jnsfsr.v51i4.11438
H. Kumari, P.U. Nisansala, E.P. Wijewardhana, D.P. Sumanasinghe, D.S. De Z. Abeysiriwardena, T.L.C.N. Kusalani
The present study was undertaken to ascertain the genetic control of external fruit colour, fruit length, and the number of fruits per vine in bitter gourd using reciprocal crosses of Momordica charantia var. muricata and M. charantia var. charantia and to identify suitable lines of M. charantia var. muricata to be used in bitter gourd improvement programmes. Muricata accession collected from Girandurukotte (GK), Sri Lanka, was selected as a suitable accession for crop improvement based on higher gynoecy and consistency of characteristics. Crossing success between Charantia and Muricata varieties was 100 % indicating cross-compatibility between the two types. External fruit colour, fruit length and the number of fruits per vine of bitter gourd were found to be quantitative traits, potentially controlled by many genes, each with a small effect. The number of fruits per vine was found to show cytoplasmic inheritance, as the F1 generation recorded fruit numbers per vine similar to those of Charantia varieties, when Charantia varieties were used as the female parent of the reciprocal crosses made between Charantia and Muricata varieties. However, the suspected cytoplasmic effect was not useful, as it influenced to reduce the number of fruits per vine. In addition, the number of fruits per vine showed several transgressive segregants in both extremes of the F2 populations. In bitter gourd improvement programmes, GK Muricata accession may be used to improve cultivated Charantia varieties with respect to fruit characteristics such as external fruit colour, fruit length and the number of fruits per vine through a breeding program with the directional selection made towards obtaining the desired characters.
{"title":"Genetic control of fruit length, external colour and number of fruits per vine in bitter gourd studied using Charantia × Muricata crosses","authors":"H. Kumari, P.U. Nisansala, E.P. Wijewardhana, D.P. Sumanasinghe, D.S. De Z. Abeysiriwardena, T.L.C.N. Kusalani","doi":"10.4038/jnsfsr.v51i4.11438","DOIUrl":"https://doi.org/10.4038/jnsfsr.v51i4.11438","url":null,"abstract":"The present study was undertaken to ascertain the genetic control of external fruit colour, fruit length, and the number of fruits per vine in bitter gourd using reciprocal crosses of Momordica charantia var. muricata and M. charantia var. charantia and to identify suitable lines of M. charantia var. muricata to be used in bitter gourd improvement programmes. Muricata accession collected from Girandurukotte (GK), Sri Lanka, was selected as a suitable accession for crop improvement based on higher gynoecy and consistency of characteristics. Crossing success between Charantia and Muricata varieties was 100 % indicating cross-compatibility between the two types. External fruit colour, fruit length and the number of fruits per vine of bitter gourd were found to be quantitative traits, potentially controlled by many genes, each with a small effect. The number of fruits per vine was found to show cytoplasmic inheritance, as the F1 generation recorded fruit numbers per vine similar to those of Charantia varieties, when Charantia varieties were used as the female parent of the reciprocal crosses made between Charantia and Muricata varieties. However, the suspected cytoplasmic effect was not useful, as it influenced to reduce the number of fruits per vine. In addition, the number of fruits per vine showed several transgressive segregants in both extremes of the F2 populations. In bitter gourd improvement programmes, GK Muricata accession may be used to improve cultivated Charantia varieties with respect to fruit characteristics such as external fruit colour, fruit length and the number of fruits per vine through a breeding program with the directional selection made towards obtaining the desired characters.","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139452505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-02DOI: 10.4038/jnsfsr.v51i4.11306
N.V.T. Jayaprada, S. Fukai, S. Geekiyanage
The anthurium is a popular cut flower worldwide having red, pink, coral, white, green, or brown spathes. There is a constant demand for new flower colours in the commercial market. Flower colour in plants is mainly determined by anthocyanins. Understanding anthocyanin variation and other factors affecting anthurium spathe colour is important for genetic engineering approaches. Therefore, our objectives were to assess the factors affecting colour variation of selected commercially available cut flower anthuriums and to determine the associated regulatory networks and transcription factors (TFs). Nineteen commercial cut flower anthurium cultivars were selected for this purpose. The colour of the spathe surface, anthocyanin location, anthocyanidin type and vacuolar pH were recorded. Anthocyanin associated Gene Network Model generation and analysis were carried out. The CIELAB colourimeter procedure indicated the colour variation among the selected 19 cultivars in terms of colour type, colour intensity, chroma, and hue angle. The location of anthocyanin was limited to mesophyll and epidermal cells. Cyanidin was detected in tested anthurium cultivars as the main anthocyanidin. The pH gradient in pigment extracts indicated a variation with a range of 4.6 to 4.94. The gene pathways of anthocyanin biosynthesis and transport were associated with that of the vacuolar pH/H+ pump according to Gene Network Model. Three pathways were regulated by an R2R3-MYB transcription factor. Although, cyanidin was the only pigment in all the tested cultivars, different pH levels by R2R3-MYB regulated V-H+ synthase was suggested to be the cause of the high colour variation in addition to the anthocyanidin type and location. Our results indicate the application of R2R3-MYB transcription factor genes for desirable vacuolar pH maintenance in genetic engineering of the blue anthurium in the future.
{"title":"Does an R2R3-MYB transcription factor affect anthurium spathe colour variation via regulation of vacuolar pH?","authors":"N.V.T. Jayaprada, S. Fukai, S. Geekiyanage","doi":"10.4038/jnsfsr.v51i4.11306","DOIUrl":"https://doi.org/10.4038/jnsfsr.v51i4.11306","url":null,"abstract":"The anthurium is a popular cut flower worldwide having red, pink, coral, white, green, or brown spathes. There is a constant demand for new flower colours in the commercial market. Flower colour in plants is mainly determined by anthocyanins. Understanding anthocyanin variation and other factors affecting anthurium spathe colour is important for genetic engineering approaches. Therefore, our objectives were to assess the factors affecting colour variation of selected commercially available cut flower anthuriums and to determine the associated regulatory networks and transcription factors (TFs). Nineteen commercial cut flower anthurium cultivars were selected for this purpose. The colour of the spathe surface, anthocyanin location, anthocyanidin type and vacuolar pH were recorded. Anthocyanin associated Gene Network Model generation and analysis were carried out. The CIELAB colourimeter procedure indicated the colour variation among the selected 19 cultivars in terms of colour type, colour intensity, chroma, and hue angle. The location of anthocyanin was limited to mesophyll and epidermal cells. Cyanidin was detected in tested anthurium cultivars as the main anthocyanidin. The pH gradient in pigment extracts indicated a variation with a range of 4.6 to 4.94. The gene pathways of anthocyanin biosynthesis and transport were associated with that of the vacuolar pH/H+ pump according to Gene Network Model. Three pathways were regulated by an R2R3-MYB transcription factor. Although, cyanidin was the only pigment in all the tested cultivars, different pH levels by R2R3-MYB regulated V-H+ synthase was suggested to be the cause of the high colour variation in addition to the anthocyanidin type and location. Our results indicate the application of R2R3-MYB transcription factor genes for desirable vacuolar pH maintenance in genetic engineering of the blue anthurium in the future.","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139453135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-02DOI: 10.4038/jnsfsr.v51i4.11991
A. Abeysekera
The confidence that scientists and the public have in the reliability of the primary scientific literature stems from a cardinal feature of scientific knowledge itself; that it is public knowledge open to verification by anyone independently, and that its validity does not depend upon the authority of the individual/persons reporting the knowledge. Thus, it has been the norm that extravagant claims made on deliberately falsified data (or wrongly interpreted data driven by an overabundance of enthusiasm) were rare, and exposed early on after publication. Retractions, when made by authors due to honest errors, served to enhance the confidence in scientific knowledge, and is considered a demonstration of the inherent nature of scientific knowledge to correct itself, as it progresses.However, the large number of retractions by publishers that are now being reported has made a dent in this confidence. It was recently reported in Nature that there were over 10,000 retractions in 2023. The reasons for the retractions were multifarious, and included papers identified as coming from paper mills, papers where images and data had been manipulated and papers published after fraudulent peer review.Of special interest was the observation that the largest number of retractions were from special issues related to specific topics or conference proceedings. There is a legitimate view that special issues serve a purpose and can enhance the profile of a journal. Nevertheless, it is ironical that special issues today are not special, but have become common, and have lost the original high purpose for which they were intended; to bring together a limited number of papers by established scientists on an emerging topic of relevance and current interest, which could spur on further development.Editorial boards need to be alert to the increasing amount of malpractice among unethical practitioners professing to be scientists. The COPE documents on retractions provide sound and practical guidelines to minimize the publication of dubious papers which would need to be retracted later.
{"title":"Reliability of the primary scientific literature","authors":"A. Abeysekera","doi":"10.4038/jnsfsr.v51i4.11991","DOIUrl":"https://doi.org/10.4038/jnsfsr.v51i4.11991","url":null,"abstract":"The confidence that scientists and the public have in the reliability of the primary scientific literature stems from a cardinal feature of scientific knowledge itself; that it is public knowledge open to verification by anyone independently, and that its validity does not depend upon the authority of the individual/persons reporting the knowledge. Thus, it has been the norm that extravagant claims made on deliberately falsified data (or wrongly interpreted data driven by an overabundance of enthusiasm) were rare, and exposed early on after publication. Retractions, when made by authors due to honest errors, served to enhance the confidence in scientific knowledge, and is considered a demonstration of the inherent nature of scientific knowledge to correct itself, as it progresses.However, the large number of retractions by publishers that are now being reported has made a dent in this confidence. It was recently reported in Nature that there were over 10,000 retractions in 2023. The reasons for the retractions were multifarious, and included papers identified as coming from paper mills, papers where images and data had been manipulated and papers published after fraudulent peer review.Of special interest was the observation that the largest number of retractions were from special issues related to specific topics or conference proceedings. There is a legitimate view that special issues serve a purpose and can enhance the profile of a journal. Nevertheless, it is ironical that special issues today are not special, but have become common, and have lost the original high purpose for which they were intended; to bring together a limited number of papers by established scientists on an emerging topic of relevance and current interest, which could spur on further development.Editorial boards need to be alert to the increasing amount of malpractice among unethical practitioners professing to be scientists. The COPE documents on retractions provide sound and practical guidelines to minimize the publication of dubious papers which would need to be retracted later.","PeriodicalId":17429,"journal":{"name":"Journal of the National Science Foundation of Sri Lanka","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139453204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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