Roads constructed in fragile Siwaliks are prone to large number of instabilities. Bhalubang–Shiwapur section of Mahendra Highway lying in Western Nepal is one of them. To understand the landslide causative factor and...Roads constructed in fragile Siwaliks are prone to large number of instabilities. Bhalubang–Shiwapur section of Mahendra Highway lying in Western Nepal is one of them. To understand the landslide causative factor and to predict future occurrence of the landslides, landslide susceptibility mapping(LSM) of this region was carried out using frequency ratio(FR) and weights-of-evidence(W of E) models. These models are easy to apply and give good results. For this, landslide inventory map of the area was prepared based on the aerial photo interpretation, from previously published/unpublished reposts, and detailed field survey using GPS. About 332 landslides were identified and mapped, among which 226(70%) were randomly selected for model training and the remaining 106(30%) were used for validation purpose. A spatial database was constructed from topographic, geological, and land cover maps. The reclassified maps based on the weight values of frequency ratio and weights-of-evidence were applied to get final susceptibility maps. The resultant landslide susceptibility maps were verified andcompared with the training data, as well as with the validation data. From the analysis, it is seen that both the models were equally capable of predicting landslide susceptibility of the region(W of E model(success rate = 83.39%, prediction rate = 79.59%); FR model(success rate = 83.31%, prediction rate = 78.58%)). In addition, it was observed that the distance from highway and lithology, followed by distance from drainage, slope curvature, and slope gradient played major role in the formation of landsides. The landslide susceptibility maps thus produced can serve as basic tools for planners and engineers to carry out further development works in this landslide prone area.展开更多
Antioxidant capacities and phenolic contents of medicinal plants namely Usnea longifolia, Cetraria nepalensis, Parmelia minarum, Everniastrum nepalense, Rhododendron anthopogon and Fritillaria delavayi were analyzed v...Antioxidant capacities and phenolic contents of medicinal plants namely Usnea longifolia, Cetraria nepalensis, Parmelia minarum, Everniastrum nepalense, Rhododendron anthopogon and Fritillaria delavayi were analyzed via Folin-Ciocaltau assay, Ferric reducing activity power assay and 2,2-Diphenyl-1-picrylhydrazyl assay. All the tested plants depicted the antioxidant activity with variation in extent of activity among the plants. The FRAP (F-value: 387.4), DPPH (F-value: 89.684) and TPC (F-value: 559.163) values between the extracts showed the highly significant differences (P < 0.01). This study indicated the strong antioxidant potential of R. anthopogon among the plants tested.展开更多
Acid lime (Citrus aurantifolia) fruits are cultivated in terai, mid hill and high hill districts of Nepal. It is cross-pollinated crop and has a high variation in fruit characters within the species. Fruit character i...Acid lime (Citrus aurantifolia) fruits are cultivated in terai, mid hill and high hill districts of Nepal. It is cross-pollinated crop and has a high variation in fruit characters within the species. Fruit character is the main basis of genotype selection. Study of fruit diversity is of utmost importance to select the elite genotypes for breeding and variety development program. Therefore, total of 620 fruit samples were collected and evaluated in the main production season of the year 2010 and 2011, from 62 bearing trees. Samples were collected from three agro-ecological domains, representing terai, mid hill and high hill areas of eastern Nepal. Elite landraces were selected on the basis of scoring fruit characters. High variation in vitamin C was observed between the terai (57.4 mg) and high hill (72.5 mg) samples. Amount of juice was 36.8% in mid hill and 44.1% in terai samples. Higher percent of juice and total soluble solids (TSS) observed in terai samples but tritable acidity (TA) and vitamin C was low as compare to high hills. There was significantly negative correlation found in fruit weight, fruit diameter, juice percent and seed number, whereas significantly positive correlation was in pulp and vitamin C, with altitude range. Total landraces were separated in five major cluster group. Variation in the level of similarity was observed among the cluster groups. The variability distance of fruit characters was highest in cluster group II (–17.45%) and lowest in cluster group V (58.5%). On the basis of scoring number of fruit characters, total four elite genotypes i.e. LD-49 from mid hills, LD-23 and LT-17 from higher hills and LM-44 from terai were selected for conservation, breeding and variety development purpose.展开更多
Acid lime (Citrus aurantifolia) is an important commercial fruits crop, cultivated in terai to high hills of Nepal. High variation of acid lime fruits are observed in existing landraces due to crossing within the othe...Acid lime (Citrus aurantifolia) is an important commercial fruits crop, cultivated in terai to high hills of Nepal. High variation of acid lime fruits are observed in existing landraces due to crossing within the other citrus species. Determination of genetic variation is important to the plant breeders for development of high yielding variety and hybrids. Therefore, an attempt has been made to study the genetic diversity of 62 acid lime landraces, collected from different altitudinal range in the eastern part of Nepal, using SSR markers. Twelve Simple Sequence Repeat (SSR) primer pairs were used to assess the genetic diversity of acid lime. The average genetic similarity level among the 62 accessions was 0.77, ranging from 0.54 to 1.0 and separated five major cluster groups. Total of 33 alleles were detected by eleven primer pairs and size of alleles ranged from 50 to 225. Average polymorphic information content (PIC) value was 0.50, whereas highest 0.75 and lowest 0.18 was observed in CAT01 and GT03 loci respectively. The results of the study clearly indicated that, SSR markers are highly polymorphic and more informative for the assessment of genetic diversity of acid lime landraces.展开更多
Acid Lime (Citrus aurantifolia Swingle) is one of the important commercial fruits cultivated from terai to high hill of Nepal. It is an important source of vitamin “C” (ascorbic acid) for human nutrition. Amount of ...Acid Lime (Citrus aurantifolia Swingle) is one of the important commercial fruits cultivated from terai to high hill of Nepal. It is an important source of vitamin “C” (ascorbic acid) for human nutrition. Amount of juice, TSS (Total soluble solids), TA (Titrable acid) and vitamin C are the determining factors of quality of acid lime fruits which may vary according to bearing sides of the trees. The main objective of this study is, to determine the variation of fruit quality at different sides of the tree. Total of 15 bearing trees were selected randomly (5 trees per site) from three different agro ecological domain representing terai (1200 m asl) and samples were collected from the selected trees. Randomly ten fruits (from east, west, centre, north and south sides) were collected from each tree and analyzed for amount of vitamin C, TSS, TA and juice. Highest ascorbic acid 79.6 mg and 69.9 mg was observed in south side fruits whereas lowest 62.8 mg and 55.1 mg was observed in centre fruits in the high and mid hills zone respectively, but in terai, highest ascorbic acid 58.7 mg was observed in north side and lowest 41.8 mg was observed in centre. Highest amount of juice 43.9% was observed in south side fruits and lowest 36.6% in centre fruits, but amount of TSS 8.2% and TA 7.2% was observed in south side fruits and lowest 7.3% TSS and 7.0% TA was observed in centre fruits in high hills. In terai highest TSS 8.3% and TA 7.4% was observed in north side fruits and lowest TSS 7.3% and TA 6.7% was observed in centre fruits. Variation of TSS, TA percent and ascorbic acids was observed according to the agro ecological zone.展开更多
Soil carbon dioxide emission: soil respiration is representing a major contributor of accumulating carbon dioxide in the atmosphere that aids to accelerate global warming and altering the climate. Soil temperature, so...Soil carbon dioxide emission: soil respiration is representing a major contributor of accumulating carbon dioxide in the atmosphere that aids to accelerate global warming and altering the climate. Soil temperature, soil water content, sun light and vegetation are considered most common regulators of soil respiration variations in ecosystem. The soil respiration was measured in grassland intended to examine how the soil respiration changed with varying climatic factors, for two years (2015 and 2016) in temperate grassland of Annapurna Conservation Area (ACA), Nepal. In the study, soil temperature accounted exponential function of soil respiration variation at 42.9%, 19.1% and 23.3%, and temperature sensitivity of the soil respiration (Q10) obtained at 6.2, 1.4 and 1.8 in October 2015 and April 2016 and both the measurements were combined, respectively. Significant negative (R2 = 0.50, p < 0.05, October 2015) and positive (R2 = 0.084, p < 0.05, April 2016) exponential function of soil respiration and soil water content were determined, where high soil respiration values were always measured between 30% and 35% of the soil water content. However, linear significant relationship was determined (R2 = 0.376, p < 0.05) between soil respiration and photosynthetic photon flux density (PPFD). Soil respiration value averaged in October 2015 was 357 mg CO2 m-2 h-1 and in April 2016 it was 444.6 mg CO2 m-2 h-1. Above- and below-ground plant biomasses were obtained at 231.1 g d w m-2 and 1538.8 g d w m-2 in October, and at 449.9 g d w m-2 and 349.0 g d w m-2 in April, respectively. This study showed variation of soil respiration in relation to the factors such as soil temperature, soil water content and photosynthetic photon flux density signifying their importance in governing ecosystem function and carbon balance of the temperate grassland ecosystem.展开更多
Owing to the high demand, Swertia chirayita populations in the wild are being depleted beyond its regeneration capacity. S. chirayita is one of the most valuable medicinal plants of Nepal in trade. Present Molecular i...Owing to the high demand, Swertia chirayita populations in the wild are being depleted beyond its regeneration capacity. S. chirayita is one of the most valuable medicinal plants of Nepal in trade. Present Molecular investigation was undertaken to understand the level of genetic diversity in five S. chirayita populations of Nepal using Polymerase Chain Reaction (PCR)-based Random amplified polymorphic DNA (RAPD) technique. Thirty four accessions of S. chirayita along with six outlier accessions were analyzed using 26 arbitrary primers. Of the total 285 amplified bands scored for S. chirayita, 263 bands (92.28%) were polymorphic. Two major clusters were revealed in the phenogram generated from cluster analysis using NTSYS-PC software (version 2.21i) for the geographic populations under study. Principal Coordinate Analysis further substantiated the results of the phenograms. Swertia chirayita populations from Sankhuwasabha and Terathum were found to be genetically closest (68%, similar) whilst Nagarjun and Terathum were found to be most distant (33%, similar).The high genetic polymorphism reflected in S. chirayita populations indicates the good survival potentiality and adaptability in changing environmental scenario. The results thus produced might be helpful to plant breeders for elite cultivar development. The RAPD-PCR technique is found to be the rapid and effective tool for genetic diversity assessment in S. chirayita populations and generated insights for the formulation of conservation strategy of this vulnerable species together with its phytochemical distinctiveness.展开更多
Soil CO<sub>2</sub> efflux is an ongoing process of respiration from soil;plant parts/ microbes below the ground to the atmosphere which is known for faster cycling of carbon sources. A large portion of ca...Soil CO<sub>2</sub> efflux is an ongoing process of respiration from soil;plant parts/ microbes below the ground to the atmosphere which is known for faster cycling of carbon sources. A large portion of carbon sequestered and fixed by forests is returned to the atmosphere through soil CO<sub>2</sub> efflux and multiple controlling parameters mainly temperature, precipitation, and growth factors interact with the soil CO<sub>2</sub> efflux variation. This study assessed the soil CO<sub>2</sub> efflux every month for consecutive 2-years (August 2015 to July 2017) by using the closed chamber method to determine the role of ecological parameters that govern the soil CO<sub>2</sub> efflux and its temporal modification in a sub-tropical mixed forest of central region in Nepal. The results of this study manifested that soil CO<sub>2</sub> efflux accounted 63.2% (y = 31.96e<sup>0.128x</sup>), 71.3% (y = 44.77e<sup>0.123x</sup>) and 64.5% (y = 44.11e<sup>0.117x</sup>) variations in soil temperature with significantly (p < 0.05) exponential positive relation in the year 2015/2016, 2016/2017 and the two years when merged. And the temperature sensitivity value (Q<sub>10</sub>) of the soil CO<sub>2</sub> efflux was 3.6, 3.4, and 3.2, respectively. Soil water content also expressed significantly (p < 0.05) positive exponential effect on soil CO<sub>2</sub> efflux and accounted 62.0% (y = 138.3e<sup>0.057x</sup>), 46.1% (y = 88.42e<sup>0.052x</sup>) and 40.5% (y = 133.1e<sup>0.0447x</sup>) in its variability in different years and the merged years. Evident variations of soil CO<sub>2</sub> efflux, soil temperature, soil water content, and litter were observed in the forest seasonally and inter-annually. Two years mean total annual soil CO<sub>2</sub> efflux of the forest was estimated at 904.76 g C·m<sup>-2</sup>·y<sup>-1</sup>. The study revealed that sub-tropical forests could be more influenced by precipitation regimes in progressing warm climates i.e. vulnerable to climate change, illustrating the comprehensive dynamics of the representative forest carbon cycle in the tropical region.展开更多
The community forest program in Nepal is one of the successful conservation initiatives.Tree species in a forest ecosystem have a fundamental role in maintaining the vegetation structure,complexity,and heterogeneity.T...The community forest program in Nepal is one of the successful conservation initiatives.Tree species in a forest ecosystem have a fundamental role in maintaining the vegetation structure,complexity,and heterogeneity.This study analyzes the composition and regeneration of tree species in five community forests(CFs)of the sub-tropical region,Lamjung district,Nepal for preparing baseline data for long-term research projects and helps the community to manage their CFs scientifically.Tree species data were generated by stratified random sampling using 35 quadrate plots(size:20 m x 20 m).The density of adult trees in the forests ranged from 575 Ind ha^(-1)(Tilahar CF)to 1196 Ind/ha(Deurali Thadopakha CF).The sapling ranged from 2533 Ind ha^(-1)(Tilahar CF)to 4000 Ind ha^(-1)(Thuliban CF)and seedling from 19583 Ind ha^(-1)(Tilahar CF)to 37500 Ind ha^(-1)(Thuliban CF).Similarly,the adult tree basal area varied from 28.34 m^(2) ha^(-1)(Tilahar CF)to 49 m^(2) ha^(-1)(Deurali CF).The adult tree diversity index(Shannon-Weiner’s H)also ranged from 1.08(Thuliban CF)to 1.88(Tilahar CF).The tree species such as Sapium insigne,Ficus benghalensis,Lagerstroemia parviflore,Albizia sp.and Pinus roxburghii were weak regeneration.In general,the forests have good regeneration status except for Tilahar Community Forest,but based on the DBH size class distribution diagram,there is no sustainable regeneration.Among the five community forests the DBH size of adults was significantly different,and the DBH of Deurali Thadopakha was the lowest.But only few species have good regeneration and most of the species have weak,poor to no regeneration.The dominancy of fewer species like Shorea robusta,Castanopsis indica,and Schima wallichii accordingly maintain the overall regeneration of tree of CFs,so further plantation needs to be done inside the CF by triage accordingly those species whose regeneration has poor.展开更多
Research on social aspects of energy and those applying machine learning(ML)is limited compared to the‘hard’disciplines such as science and engineering.We aim to contribute to this niche through this multidisciplina...Research on social aspects of energy and those applying machine learning(ML)is limited compared to the‘hard’disciplines such as science and engineering.We aim to contribute to this niche through this multidisciplinary study integrating energy,social science and ML.Specifically,we aim:(i)to compare the applicability of different ML models in household(HH)energy;and(ii)to explain people’s perception of HH energy using the most appropriate model.We carried out cross-sectional survey of 323 HHs in a developing country(Nepal)and extracted 14 predictor variables and one response variable.We tested the performance of seven ML models:K-Nearest Neighbors(KNN),Multi-Layer Perceptron(MLP),Extra Trees Classifier(ETC),Random Forest(RF),Ridge Classifier(RC),Multinomial Regression–Logit(MR-L)and Probit(MR-P)in classifying people’s responses.The models were evaluated against six metrics(confusion matrix,precision,f1 score,recall,balanced accuracy and overall accuracy).In this study,ETC outperformed all other models demonstrating a balanced accuracy of 0.79,0.95 and 0.68 respectively for the Agree,Neutral and Disagree response categories.Results showed that,compared to conventional statistical models,data driven ML models are better in classifying people’s perceptions.It was seen that the majority of the surveyed people from rural(68%)and semi-urban areas(67%)tend to resist energy changes due to economic constraints and lack of awareness.Interestingly,most(73%)of the urban residents are open to changes,but still resort to fuel-stacking because of distrust in the state.These grass-root level responses have strong policy implications.展开更多
Objective:To study chemical constituents of essential oil of the roots of Nardostachys jatamansi found in different regions of Nepal and also to investigate phytochemical as well as antimicrobial activity of the sampl...Objective:To study chemical constituents of essential oil of the roots of Nardostachys jatamansi found in different regions of Nepal and also to investigate phytochemical as well as antimicrobial activity of the sample with high yield of essential oil.Methods:The essential oils of roots of plant from five different regions were extracted by hydro-distillation and analyzed by gas chromatography-mass spectroscopy for their chemical constituents.The root samples were also subjected to hydro-alcoholic extraction and then fractionated with hexane,chloroform,n-butanol and water so as to perform phytochemical screening and antimicrobial activity.Results:The essential oil yield of sample from Jumla was found to be the highest followed by a sample from Nepalgunj,Surkhet and Kathmandu whereas that of sample from Dharan was found to be the lowest.Gas chromatography-mass spectrometer analysis of essential oil of five samples showed that“2-beta pinene”appeared dominated in three samples,namely,6VJ Nepalgunj,9VJA Jumla and 10VJ Surkhet.Similarly“alkohol aus neoclovenoxid”in 8VJ Dharan and“methoxy phenyloxime”in 13VJA Kathmandu was found to be present in the highest amount.Phytochemical screening of different fractions of sample 9VJA Jumla showed the presence of alkaloids,terpenoids,glycosides,proteins and amino acids,and carbohydrates etc.Antimicrobial susceptibility test of same fractions showed the n-butanol fraction potent against all pathogens and most affected one was Escherichia coli.Conclusions:Our study suggests that the essential oil of Nardostachys jatamansi found in Nepal contains more than 80 compounds with their quality and quantity differing from place to place.展开更多
The control ofblack and odorous substances in sediments is of crucial importance to improve the urban ecological landscape and to restore water environments accordingly.In this study,chemical oxidation by the oxidants...The control ofblack and odorous substances in sediments is of crucial importance to improve the urban ecological landscape and to restore water environments accordingly.In this study,chemical oxidation by the oxidants NaClO,H2O2,and KMnO4 was proposed to achieve rapid control of black and odorous substances in heavily-polluted sediments.Results indicate that NaClO and KMnO4 are effective at removing Fe(II)and acid volatile sulfides.The removal efficiencies of Fe(II)and AVS were determined to be 45.2%,94.1%,and 93.7%,89.5%after 24-h exposure to NaClO and KMnO4 at 0.2 mmol/g,respectively.Additionally,rapid oxidation might accelerate the release of pollutants from sediment.The release of organic matters and phosphorus with the maximum ratios of 22.1%and 51.2%was observed upon NaClO oxidation at 0.4 mmol/g.Moreover,the introduction of oxidants contributed to changes in the microbial community composition in sediment.After oxidation by NaClO and KMnO4 at 0.4 mmol/g,the Shannon index decreased from 6.72 to 5.19 and 4.95,whereas the OTU numbers decreased from 2904 to 1677 and 1553,respectively.Comparatively,H2O2 showed a lower effect on the removal of black and odorous substances,pollutant release,and changes in sediment microorganisms.This study illustrates the effects of oxidant addition on the characteristics of heavily polluted sediments and shows that chemical oxidants may be an option to achieve rapid control of black and odorous substances prior to remediation of water environments.展开更多
Objective:To determine the antibacterial efficacy and brine shrimp toxicity of extracts(hexane,dichloromethane,ethyl acetate,methanol and water)obtained from the bark of Schleichera oleosa.Methods:The powdered bark sa...Objective:To determine the antibacterial efficacy and brine shrimp toxicity of extracts(hexane,dichloromethane,ethyl acetate,methanol and water)obtained from the bark of Schleichera oleosa.Methods:The powdered bark sample was Soxhlet extracted sequentially in hexanes,dichloromethane,ethyl acetate,methanol and water.Antibacterial evaluation was carried out by following the agar diffusion method and amoxicillin disc was used as a reference.Slightly modified Meyer’s method was used to determine the toxicity of the extracts in brine shrimps.Results:Among the nine bacterial strains tested,the methanolic and aqueous extracts showed promising antibacterial efficacy against Serratia marcescens,Escherarichia coli,Bacillus subtilis and Micrococcus luteus.None of the extracts were found significantly toxic to brine shrimps.Conclusions:Strong antibacterial activity and low brine shrimp toxicity of methanolic and aqueous extracts can provide new antibacterial compounds.展开更多
Water resource is required for agricultural, industrial, and domestic activities and for environmental preservation. However, with the increase in population and growth of urbanization, industrialization, and commerci...Water resource is required for agricultural, industrial, and domestic activities and for environmental preservation. However, with the increase in population and growth of urbanization, industrialization, and commercial activities, planning and management of water resources have become a challenging task to meet various water demands globally. Information and data on streamflow hydrology are, thus, crucial for this purpose. However, availability of measured flow data in many cases is either inadequate or not available at all. When there is no gauging station available at the site of interest, various empirical methods are generally used to estimate the flow there and the best estimation is chosen. This study is focused on the estimation of monthly average flows by such methods popular in Nepal and assessment of how they compare with the results of hydrological simulation. Performance evaluation of those methods was made with a newly introduced index, Global Performance Index (GPI) utilizing six commonly used goodness-of-fit parameters viz. coefficient of determination, mean absolute error, root mean square error, percentage of volume bias, Nash Sutcliff Efficiency and Kling-Gupta Efficiency. This study showed that hydrological modeling is the best among the considered methods of flow estimation for ungauged catchments.展开更多
Lichens are unique individuals which have been widely used in traditional medicines. This study was focused on the bioassayguided phytochemical investigation, and bioactivity evaluation on a lichens species, Parmotrem...Lichens are unique individuals which have been widely used in traditional medicines. This study was focused on the bioassayguided phytochemical investigation, and bioactivity evaluation on a lichens species, Parmotrema cooperi. This first bioassaydirected chemical study on P. cooperi has led to the isolation of ethyl heamatomate （1）, atraric acid （2）, ethyl orsellinate （3）, orsellinic acid （4）, lecanoric acid （5）, gyrophoric acid （6）, and licanorin （7）. The structures of 1-7 were mainly elucidated from spectroscopic methods including 1D, and 2D NMR spectroscopy, and mass spectrometry. These compounds were evaluated for their antiglycation, urease, a-chymotrypsin, and β-glucoronidase inhibitory activities. Few of the phenolic compounds showed significant, while most of them showed good inhibition of protein glycation, and urease activities.展开更多
Alzheimer’s disease(AD),a neurodegenerative disorder,has been determined as an outcome of genetic as well as behavioral conditions.The complete understanding of its generation and progress is yet to be understood.How...Alzheimer’s disease(AD),a neurodegenerative disorder,has been determined as an outcome of genetic as well as behavioral conditions.The complete understanding of its generation and progress is yet to be understood.However,there has been a significant progress in the diagnosis and identification of the associated risk factors of AD.Several of the risk factors were found connected with cholesterol.Scientists are mainly focusing on the reduction of amyloid β and stabilization of tau protein towards the development of its drugs.To modulate amyloid β,the key components of cholesterol metabolism have been attractive targets and the enzymes involved in the phosphorylation of tau have been tried to stabilize tau protein.This review article briefly highlights the symptoms,risk factors,and drug targets of AD.展开更多
文摘Roads constructed in fragile Siwaliks are prone to large number of instabilities. Bhalubang–Shiwapur section of Mahendra Highway lying in Western Nepal is one of them. To understand the landslide causative factor and to predict future occurrence of the landslides, landslide susceptibility mapping(LSM) of this region was carried out using frequency ratio(FR) and weights-of-evidence(W of E) models. These models are easy to apply and give good results. For this, landslide inventory map of the area was prepared based on the aerial photo interpretation, from previously published/unpublished reposts, and detailed field survey using GPS. About 332 landslides were identified and mapped, among which 226(70%) were randomly selected for model training and the remaining 106(30%) were used for validation purpose. A spatial database was constructed from topographic, geological, and land cover maps. The reclassified maps based on the weight values of frequency ratio and weights-of-evidence were applied to get final susceptibility maps. The resultant landslide susceptibility maps were verified andcompared with the training data, as well as with the validation data. From the analysis, it is seen that both the models were equally capable of predicting landslide susceptibility of the region(W of E model(success rate = 83.39%, prediction rate = 79.59%); FR model(success rate = 83.31%, prediction rate = 78.58%)). In addition, it was observed that the distance from highway and lithology, followed by distance from drainage, slope curvature, and slope gradient played major role in the formation of landsides. The landslide susceptibility maps thus produced can serve as basic tools for planners and engineers to carry out further development works in this landslide prone area.
文摘Antioxidant capacities and phenolic contents of medicinal plants namely Usnea longifolia, Cetraria nepalensis, Parmelia minarum, Everniastrum nepalense, Rhododendron anthopogon and Fritillaria delavayi were analyzed via Folin-Ciocaltau assay, Ferric reducing activity power assay and 2,2-Diphenyl-1-picrylhydrazyl assay. All the tested plants depicted the antioxidant activity with variation in extent of activity among the plants. The FRAP (F-value: 387.4), DPPH (F-value: 89.684) and TPC (F-value: 559.163) values between the extracts showed the highly significant differences (P < 0.01). This study indicated the strong antioxidant potential of R. anthopogon among the plants tested.
文摘Acid lime (Citrus aurantifolia) fruits are cultivated in terai, mid hill and high hill districts of Nepal. It is cross-pollinated crop and has a high variation in fruit characters within the species. Fruit character is the main basis of genotype selection. Study of fruit diversity is of utmost importance to select the elite genotypes for breeding and variety development program. Therefore, total of 620 fruit samples were collected and evaluated in the main production season of the year 2010 and 2011, from 62 bearing trees. Samples were collected from three agro-ecological domains, representing terai, mid hill and high hill areas of eastern Nepal. Elite landraces were selected on the basis of scoring fruit characters. High variation in vitamin C was observed between the terai (57.4 mg) and high hill (72.5 mg) samples. Amount of juice was 36.8% in mid hill and 44.1% in terai samples. Higher percent of juice and total soluble solids (TSS) observed in terai samples but tritable acidity (TA) and vitamin C was low as compare to high hills. There was significantly negative correlation found in fruit weight, fruit diameter, juice percent and seed number, whereas significantly positive correlation was in pulp and vitamin C, with altitude range. Total landraces were separated in five major cluster group. Variation in the level of similarity was observed among the cluster groups. The variability distance of fruit characters was highest in cluster group II (–17.45%) and lowest in cluster group V (58.5%). On the basis of scoring number of fruit characters, total four elite genotypes i.e. LD-49 from mid hills, LD-23 and LT-17 from higher hills and LM-44 from terai were selected for conservation, breeding and variety development purpose.
文摘Acid lime (Citrus aurantifolia) is an important commercial fruits crop, cultivated in terai to high hills of Nepal. High variation of acid lime fruits are observed in existing landraces due to crossing within the other citrus species. Determination of genetic variation is important to the plant breeders for development of high yielding variety and hybrids. Therefore, an attempt has been made to study the genetic diversity of 62 acid lime landraces, collected from different altitudinal range in the eastern part of Nepal, using SSR markers. Twelve Simple Sequence Repeat (SSR) primer pairs were used to assess the genetic diversity of acid lime. The average genetic similarity level among the 62 accessions was 0.77, ranging from 0.54 to 1.0 and separated five major cluster groups. Total of 33 alleles were detected by eleven primer pairs and size of alleles ranged from 50 to 225. Average polymorphic information content (PIC) value was 0.50, whereas highest 0.75 and lowest 0.18 was observed in CAT01 and GT03 loci respectively. The results of the study clearly indicated that, SSR markers are highly polymorphic and more informative for the assessment of genetic diversity of acid lime landraces.
文摘Acid Lime (Citrus aurantifolia Swingle) is one of the important commercial fruits cultivated from terai to high hill of Nepal. It is an important source of vitamin “C” (ascorbic acid) for human nutrition. Amount of juice, TSS (Total soluble solids), TA (Titrable acid) and vitamin C are the determining factors of quality of acid lime fruits which may vary according to bearing sides of the trees. The main objective of this study is, to determine the variation of fruit quality at different sides of the tree. Total of 15 bearing trees were selected randomly (5 trees per site) from three different agro ecological domain representing terai (1200 m asl) and samples were collected from the selected trees. Randomly ten fruits (from east, west, centre, north and south sides) were collected from each tree and analyzed for amount of vitamin C, TSS, TA and juice. Highest ascorbic acid 79.6 mg and 69.9 mg was observed in south side fruits whereas lowest 62.8 mg and 55.1 mg was observed in centre fruits in the high and mid hills zone respectively, but in terai, highest ascorbic acid 58.7 mg was observed in north side and lowest 41.8 mg was observed in centre. Highest amount of juice 43.9% was observed in south side fruits and lowest 36.6% in centre fruits, but amount of TSS 8.2% and TA 7.2% was observed in south side fruits and lowest 7.3% TSS and 7.0% TA was observed in centre fruits in high hills. In terai highest TSS 8.3% and TA 7.4% was observed in north side fruits and lowest TSS 7.3% and TA 6.7% was observed in centre fruits. Variation of TSS, TA percent and ascorbic acids was observed according to the agro ecological zone.
文摘Soil carbon dioxide emission: soil respiration is representing a major contributor of accumulating carbon dioxide in the atmosphere that aids to accelerate global warming and altering the climate. Soil temperature, soil water content, sun light and vegetation are considered most common regulators of soil respiration variations in ecosystem. The soil respiration was measured in grassland intended to examine how the soil respiration changed with varying climatic factors, for two years (2015 and 2016) in temperate grassland of Annapurna Conservation Area (ACA), Nepal. In the study, soil temperature accounted exponential function of soil respiration variation at 42.9%, 19.1% and 23.3%, and temperature sensitivity of the soil respiration (Q10) obtained at 6.2, 1.4 and 1.8 in October 2015 and April 2016 and both the measurements were combined, respectively. Significant negative (R2 = 0.50, p < 0.05, October 2015) and positive (R2 = 0.084, p < 0.05, April 2016) exponential function of soil respiration and soil water content were determined, where high soil respiration values were always measured between 30% and 35% of the soil water content. However, linear significant relationship was determined (R2 = 0.376, p < 0.05) between soil respiration and photosynthetic photon flux density (PPFD). Soil respiration value averaged in October 2015 was 357 mg CO2 m-2 h-1 and in April 2016 it was 444.6 mg CO2 m-2 h-1. Above- and below-ground plant biomasses were obtained at 231.1 g d w m-2 and 1538.8 g d w m-2 in October, and at 449.9 g d w m-2 and 349.0 g d w m-2 in April, respectively. This study showed variation of soil respiration in relation to the factors such as soil temperature, soil water content and photosynthetic photon flux density signifying their importance in governing ecosystem function and carbon balance of the temperate grassland ecosystem.
文摘Owing to the high demand, Swertia chirayita populations in the wild are being depleted beyond its regeneration capacity. S. chirayita is one of the most valuable medicinal plants of Nepal in trade. Present Molecular investigation was undertaken to understand the level of genetic diversity in five S. chirayita populations of Nepal using Polymerase Chain Reaction (PCR)-based Random amplified polymorphic DNA (RAPD) technique. Thirty four accessions of S. chirayita along with six outlier accessions were analyzed using 26 arbitrary primers. Of the total 285 amplified bands scored for S. chirayita, 263 bands (92.28%) were polymorphic. Two major clusters were revealed in the phenogram generated from cluster analysis using NTSYS-PC software (version 2.21i) for the geographic populations under study. Principal Coordinate Analysis further substantiated the results of the phenograms. Swertia chirayita populations from Sankhuwasabha and Terathum were found to be genetically closest (68%, similar) whilst Nagarjun and Terathum were found to be most distant (33%, similar).The high genetic polymorphism reflected in S. chirayita populations indicates the good survival potentiality and adaptability in changing environmental scenario. The results thus produced might be helpful to plant breeders for elite cultivar development. The RAPD-PCR technique is found to be the rapid and effective tool for genetic diversity assessment in S. chirayita populations and generated insights for the formulation of conservation strategy of this vulnerable species together with its phytochemical distinctiveness.
文摘Soil CO<sub>2</sub> efflux is an ongoing process of respiration from soil;plant parts/ microbes below the ground to the atmosphere which is known for faster cycling of carbon sources. A large portion of carbon sequestered and fixed by forests is returned to the atmosphere through soil CO<sub>2</sub> efflux and multiple controlling parameters mainly temperature, precipitation, and growth factors interact with the soil CO<sub>2</sub> efflux variation. This study assessed the soil CO<sub>2</sub> efflux every month for consecutive 2-years (August 2015 to July 2017) by using the closed chamber method to determine the role of ecological parameters that govern the soil CO<sub>2</sub> efflux and its temporal modification in a sub-tropical mixed forest of central region in Nepal. The results of this study manifested that soil CO<sub>2</sub> efflux accounted 63.2% (y = 31.96e<sup>0.128x</sup>), 71.3% (y = 44.77e<sup>0.123x</sup>) and 64.5% (y = 44.11e<sup>0.117x</sup>) variations in soil temperature with significantly (p < 0.05) exponential positive relation in the year 2015/2016, 2016/2017 and the two years when merged. And the temperature sensitivity value (Q<sub>10</sub>) of the soil CO<sub>2</sub> efflux was 3.6, 3.4, and 3.2, respectively. Soil water content also expressed significantly (p < 0.05) positive exponential effect on soil CO<sub>2</sub> efflux and accounted 62.0% (y = 138.3e<sup>0.057x</sup>), 46.1% (y = 88.42e<sup>0.052x</sup>) and 40.5% (y = 133.1e<sup>0.0447x</sup>) in its variability in different years and the merged years. Evident variations of soil CO<sub>2</sub> efflux, soil temperature, soil water content, and litter were observed in the forest seasonally and inter-annually. Two years mean total annual soil CO<sub>2</sub> efflux of the forest was estimated at 904.76 g C·m<sup>-2</sup>·y<sup>-1</sup>. The study revealed that sub-tropical forests could be more influenced by precipitation regimes in progressing warm climates i.e. vulnerable to climate change, illustrating the comprehensive dynamics of the representative forest carbon cycle in the tropical region.
文摘The community forest program in Nepal is one of the successful conservation initiatives.Tree species in a forest ecosystem have a fundamental role in maintaining the vegetation structure,complexity,and heterogeneity.This study analyzes the composition and regeneration of tree species in five community forests(CFs)of the sub-tropical region,Lamjung district,Nepal for preparing baseline data for long-term research projects and helps the community to manage their CFs scientifically.Tree species data were generated by stratified random sampling using 35 quadrate plots(size:20 m x 20 m).The density of adult trees in the forests ranged from 575 Ind ha^(-1)(Tilahar CF)to 1196 Ind/ha(Deurali Thadopakha CF).The sapling ranged from 2533 Ind ha^(-1)(Tilahar CF)to 4000 Ind ha^(-1)(Thuliban CF)and seedling from 19583 Ind ha^(-1)(Tilahar CF)to 37500 Ind ha^(-1)(Thuliban CF).Similarly,the adult tree basal area varied from 28.34 m^(2) ha^(-1)(Tilahar CF)to 49 m^(2) ha^(-1)(Deurali CF).The adult tree diversity index(Shannon-Weiner’s H)also ranged from 1.08(Thuliban CF)to 1.88(Tilahar CF).The tree species such as Sapium insigne,Ficus benghalensis,Lagerstroemia parviflore,Albizia sp.and Pinus roxburghii were weak regeneration.In general,the forests have good regeneration status except for Tilahar Community Forest,but based on the DBH size class distribution diagram,there is no sustainable regeneration.Among the five community forests the DBH size of adults was significantly different,and the DBH of Deurali Thadopakha was the lowest.But only few species have good regeneration and most of the species have weak,poor to no regeneration.The dominancy of fewer species like Shorea robusta,Castanopsis indica,and Schima wallichii accordingly maintain the overall regeneration of tree of CFs,so further plantation needs to be done inside the CF by triage accordingly those species whose regeneration has poor.
文摘Research on social aspects of energy and those applying machine learning(ML)is limited compared to the‘hard’disciplines such as science and engineering.We aim to contribute to this niche through this multidisciplinary study integrating energy,social science and ML.Specifically,we aim:(i)to compare the applicability of different ML models in household(HH)energy;and(ii)to explain people’s perception of HH energy using the most appropriate model.We carried out cross-sectional survey of 323 HHs in a developing country(Nepal)and extracted 14 predictor variables and one response variable.We tested the performance of seven ML models:K-Nearest Neighbors(KNN),Multi-Layer Perceptron(MLP),Extra Trees Classifier(ETC),Random Forest(RF),Ridge Classifier(RC),Multinomial Regression–Logit(MR-L)and Probit(MR-P)in classifying people’s responses.The models were evaluated against six metrics(confusion matrix,precision,f1 score,recall,balanced accuracy and overall accuracy).In this study,ETC outperformed all other models demonstrating a balanced accuracy of 0.79,0.95 and 0.68 respectively for the Agree,Neutral and Disagree response categories.Results showed that,compared to conventional statistical models,data driven ML models are better in classifying people’s perceptions.It was seen that the majority of the surveyed people from rural(68%)and semi-urban areas(67%)tend to resist energy changes due to economic constraints and lack of awareness.Interestingly,most(73%)of the urban residents are open to changes,but still resort to fuel-stacking because of distrust in the state.These grass-root level responses have strong policy implications.
文摘Objective:To study chemical constituents of essential oil of the roots of Nardostachys jatamansi found in different regions of Nepal and also to investigate phytochemical as well as antimicrobial activity of the sample with high yield of essential oil.Methods:The essential oils of roots of plant from five different regions were extracted by hydro-distillation and analyzed by gas chromatography-mass spectroscopy for their chemical constituents.The root samples were also subjected to hydro-alcoholic extraction and then fractionated with hexane,chloroform,n-butanol and water so as to perform phytochemical screening and antimicrobial activity.Results:The essential oil yield of sample from Jumla was found to be the highest followed by a sample from Nepalgunj,Surkhet and Kathmandu whereas that of sample from Dharan was found to be the lowest.Gas chromatography-mass spectrometer analysis of essential oil of five samples showed that“2-beta pinene”appeared dominated in three samples,namely,6VJ Nepalgunj,9VJA Jumla and 10VJ Surkhet.Similarly“alkohol aus neoclovenoxid”in 8VJ Dharan and“methoxy phenyloxime”in 13VJA Kathmandu was found to be present in the highest amount.Phytochemical screening of different fractions of sample 9VJA Jumla showed the presence of alkaloids,terpenoids,glycosides,proteins and amino acids,and carbohydrates etc.Antimicrobial susceptibility test of same fractions showed the n-butanol fraction potent against all pathogens and most affected one was Escherichia coli.Conclusions:Our study suggests that the essential oil of Nardostachys jatamansi found in Nepal contains more than 80 compounds with their quality and quantity differing from place to place.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51820105011,51578537 and 51778603)the Chinese Academy of Sciences(No.QYZDY-SSWDQC004).
文摘The control ofblack and odorous substances in sediments is of crucial importance to improve the urban ecological landscape and to restore water environments accordingly.In this study,chemical oxidation by the oxidants NaClO,H2O2,and KMnO4 was proposed to achieve rapid control of black and odorous substances in heavily-polluted sediments.Results indicate that NaClO and KMnO4 are effective at removing Fe(II)and acid volatile sulfides.The removal efficiencies of Fe(II)and AVS were determined to be 45.2%,94.1%,and 93.7%,89.5%after 24-h exposure to NaClO and KMnO4 at 0.2 mmol/g,respectively.Additionally,rapid oxidation might accelerate the release of pollutants from sediment.The release of organic matters and phosphorus with the maximum ratios of 22.1%and 51.2%was observed upon NaClO oxidation at 0.4 mmol/g.Moreover,the introduction of oxidants contributed to changes in the microbial community composition in sediment.After oxidation by NaClO and KMnO4 at 0.4 mmol/g,the Shannon index decreased from 6.72 to 5.19 and 4.95,whereas the OTU numbers decreased from 2904 to 1677 and 1553,respectively.Comparatively,H2O2 showed a lower effect on the removal of black and odorous substances,pollutant release,and changes in sediment microorganisms.This study illustrates the effects of oxidant addition on the characteristics of heavily polluted sediments and shows that chemical oxidants may be an option to achieve rapid control of black and odorous substances prior to remediation of water environments.
基金Supported by Nepal Academy of Science and Technology.
文摘Objective:To determine the antibacterial efficacy and brine shrimp toxicity of extracts(hexane,dichloromethane,ethyl acetate,methanol and water)obtained from the bark of Schleichera oleosa.Methods:The powdered bark sample was Soxhlet extracted sequentially in hexanes,dichloromethane,ethyl acetate,methanol and water.Antibacterial evaluation was carried out by following the agar diffusion method and amoxicillin disc was used as a reference.Slightly modified Meyer’s method was used to determine the toxicity of the extracts in brine shrimps.Results:Among the nine bacterial strains tested,the methanolic and aqueous extracts showed promising antibacterial efficacy against Serratia marcescens,Escherarichia coli,Bacillus subtilis and Micrococcus luteus.None of the extracts were found significantly toxic to brine shrimps.Conclusions:Strong antibacterial activity and low brine shrimp toxicity of methanolic and aqueous extracts can provide new antibacterial compounds.
文摘Water resource is required for agricultural, industrial, and domestic activities and for environmental preservation. However, with the increase in population and growth of urbanization, industrialization, and commercial activities, planning and management of water resources have become a challenging task to meet various water demands globally. Information and data on streamflow hydrology are, thus, crucial for this purpose. However, availability of measured flow data in many cases is either inadequate or not available at all. When there is no gauging station available at the site of interest, various empirical methods are generally used to estimate the flow there and the best estimation is chosen. This study is focused on the estimation of monthly average flows by such methods popular in Nepal and assessment of how they compare with the results of hydrological simulation. Performance evaluation of those methods was made with a newly introduced index, Global Performance Index (GPI) utilizing six commonly used goodness-of-fit parameters viz. coefficient of determination, mean absolute error, root mean square error, percentage of volume bias, Nash Sutcliff Efficiency and Kling-Gupta Efficiency. This study showed that hydrological modeling is the best among the considered methods of flow estimation for ungauged catchments.
基金the financial support of the Higher Education Commission,Pakistan,through the project entitled"High Resolution X-Ray Analysis of Pharmaceutically Important Enzymes in Complex with Plant-based Inhibitions as basis for Rational Drug Design (20-1364/ R&D/09)"
文摘Lichens are unique individuals which have been widely used in traditional medicines. This study was focused on the bioassayguided phytochemical investigation, and bioactivity evaluation on a lichens species, Parmotrema cooperi. This first bioassaydirected chemical study on P. cooperi has led to the isolation of ethyl heamatomate （1）, atraric acid （2）, ethyl orsellinate （3）, orsellinic acid （4）, lecanoric acid （5）, gyrophoric acid （6）, and licanorin （7）. The structures of 1-7 were mainly elucidated from spectroscopic methods including 1D, and 2D NMR spectroscopy, and mass spectrometry. These compounds were evaluated for their antiglycation, urease, a-chymotrypsin, and β-glucoronidase inhibitory activities. Few of the phenolic compounds showed significant, while most of them showed good inhibition of protein glycation, and urease activities.
文摘Alzheimer’s disease(AD),a neurodegenerative disorder,has been determined as an outcome of genetic as well as behavioral conditions.The complete understanding of its generation and progress is yet to be understood.However,there has been a significant progress in the diagnosis and identification of the associated risk factors of AD.Several of the risk factors were found connected with cholesterol.Scientists are mainly focusing on the reduction of amyloid β and stabilization of tau protein towards the development of its drugs.To modulate amyloid β,the key components of cholesterol metabolism have been attractive targets and the enzymes involved in the phosphorylation of tau have been tried to stabilize tau protein.This review article briefly highlights the symptoms,risk factors,and drug targets of AD.
