Showing 6 results for Gautam
Volume 1, Issue 4 (12-2013)
Abstract
This paper presents the analysis of the onset and withdrawal dates and the duration of summer monsoon over Nepal for last 63 years (1951-2013). The trend analysis revealed that both the onset and withdrawal of summer monsoon are delayed in recent years. The statistical analysis using cumulative deviation and Worsley likelihood tests showed a step jump in mean withdrawal date after the year 1997. The mean withdrawal date after 1997 is later than the normal withdrawal date by 10 days. Although, the trend for onset is statistically insignificant, the trend for withdrawal is significant at 5% level. Stationarity tests for the period of 1951-1996 and 1997-2013 also revealed that both the onset and withdrawal series are non-stationary. A step change in withdrawal date with delayed trend on both onset and withdrawal coupled with longer duration suggests a temporal shift in the monsoon pattern over Nepal after 1997. The temporal shift in the monsoon is consistent with published findings on the effect of global climate change on the dynamics of the South Asian summer monsoon precipitation. The shifting pattern of the summer monsoon exerts a strong stress on agriculture, water resources, ecosystems, human health and the overall economy of the country.
Volume 2, Issue 4 (12-2014)
Abstract
Precipitation data is of utmost importance to carry out many hydro-meteorological studies. Observed warming over several decades has been linked to changes in the large-scale hydrological cycle such as: increasing atmospheric water vapour content, changing precipitation patterns, intensity and extremes, reduced snow cover and widespread melting of ice, and changes in soil moisture and runoff. Precipitation changes show substantial spatial and inter-decadal variability. General Circulation Models (GCMs), representing physical processes in the atmosphere, ocean, cryosphere and land surface, are the most advanced tools currently available for simulating the response of the global climate system. Recent interest in global warming has also increased concerns about the possible changes in rainfall amount including floods and drought patterns. This study is based on statistical downscaling, which provide good example of focusing on predicting the rainfall using the input of coarse GCM outputs. In this study, we have used GCM outputs for predicting the rainfall. It is obtained from the study that predicted rain values are higher for the first 30 years in compared to remaining prediction periods. The result has shown that winter rainfall may highly decrease in compared to monsoon, post monsoon and pre-monsoon seasons
Volume 5, Issue 4 (12-2016)
Abstract
This paper deals with the study of a leaf spot disease observed on Aloe vera leaves in various nurseries and botanical gardens during the routine surveys of two consecutive years of 2010 and 2011. The symptoms appeared in the form of circular to oval, brown to black, sunken spots on abaxial surface of leaves. The disease was observed only in January to February during the survey. Colonieson PDA were velvety, dark olivaceous to greenish black in colour. The identification of the pathogen was done phenotypically using disease symptoms and microscopic characteristics. Further investigation identified it as Cladosporium sphaerospermum Penzig which was also confirmed at Indian Type Culture Collection (ITCC), IARI, New Delhi, India. According to the literature, this is the first report of Cladosporium sphaerospermum as causal agent of leaf spot disease on A. vera from India.
Manoj Sharma, Buddhi Ram Oli, Ishan Gautam,
Volume 10, Issue 3 (9-2024)
Abstract
Dragonflies and damselflies are bioindicator species belonging to the class Insecta. The research was conducted in the Karnali River basin from April to early October 2022 to contribute and update the Odonata checklist of Nepal including documenting regional new species. From the odonatological survey, four species viz., Aristocypha spuria Selys, 1879, Pseudocopera ciliata (Selys, 1863), Aciagrion occidentale Laidlaw, 1919 and Zyxomma petiolatum Rambur, 1842 were recorded for the first time from Nepal. Besides these, Copera marginipes (Rambur, 1842), Copera vittata (Selys, 1863), Prodasineura autumnalis (Fraser, 1922), Agriocnemis clauseni Fraser, 1992, Ceriagrion cerinorubellum (Brauer, 1865), Cephalaeschna viridifrons (Fraser, 1923), Gynacantha incisura Fraser, 1935, Gynacanthaeschna sikkima (Karsch, 1891), Lamelligomphus risi (Fraser, 1922), Scalmogomphus bistrigatus (Hagen in Selys, 1854), Rhodothemis rufa (Rambur, 1842), Tetrathemis platyptera Selys, 1868 and Urothemis signata signata (Rambur, 1862) were newly recorded for western region of Nepal.
Volume 10, Issue 4 (11-2021)
Abstract
Butterflies are flagship taxa and bio-indicator of terrestrial ecosystems. Studies of butterflies are performed in different regions of Nepal, but no detailed research has been carried out in Tanahun. Hence, this study was conducted to determine the species diversity and abundance of butterflies in Byas municipality-6 of the Tanahun, Nepal, from March to November 2020. The Pollard walk method was used for the data collection. A total of six transects of 500 m, two in each habitat type (forests, settlements, and agricultural lands), were laid out randomly. The study was performed in three seasons (9 months); Pre-Monsoon (March to May), Monsoon (June to September), and Post-Monsoon (October to November). Each transect was surveyed nine times (once a month) to record species in each month. Data were pooled and analyzed with SPSS. A total of 1,753 individuals of 149 butterfly species from 92 genera and six families were recorded during the study. The overall Shannon-Wiener and Margalef diversity indices were H = 4.17 and R = 19.95. Pielou’s Evenness was E = 0.83. Nymphalidae was the most diverse, richest species, and most abundant family (H = 3.33, R = 8.30, N = 851). Species evenness was maximum in the family Papilionidae (E = 0.88). The forests comprised the maximum number of species (115 species, 898 individuals). The maximum number of species was recorded in March (106 species), while the highest species abundance was in June (268 individuals). The result of this study could be the baseline for further researches on butterflies in the Tanahun district.
Volume 15, Issue 5 (9-2013)
Abstract
Molecular characterization of 19 Jatropha accessions that included 15 accessions of J.curcas and 4 different species was carried out using 3 different markers systems. Highest polymorphism (96.67%) was recorded by RAPD followed by DAMD (91.02%) and ISSR (90%). Polymorphism Information Content (PIC) was higher for DAMD (0.873) and almost equal for RAPD (0.863) and ISSR (0.862) markers, whereas Resolving Power (Rp) was found to be higher for RAPD as compared to the other two marker systems. Marker Index (MI) values varied greatly with highest (19.07) in RAPD. Shannon index (i), observed number of alleles (na), effective number of alleles (ne) and Nei’s genetic diversity (h) values were found to be significantly higher for ISSR as compared to RAPD and DAMD markers. Thus, all the markers proved to be equally efficient for diversity studies in Jatropha. Several alleles in all the markers indicated J. gossypiifolia as one of the parents of J. tanjorensis. Dendrograms and PCA plots generated based on RAPD showed three major clusters with J. integerrima and J. podagrica falling in group I, fifteen J. curcas accessions in group II, and J. gossypiifolia as an outlier in group III. DAMD markers also showed similar clustering pattern whereas ISSR showed last cluster of J. gossypiifolia and J. tanjorensis. These results may provide a future base for conservation and characterization of available Jatropha genetic resources.
