43 research outputs found

    Fitness costs and inheritance of Bt Cry2Ab2 resistance in fall armyworm, Spodoptera frugiperda (J.E. Smith)

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    Evolution of resistance in target pest populations is a major threat to the sustainability of transgenic crops expressing Bacillus thuringiensis (Bt) proteins. Fall armyworm, Spodoptera frugiperda (J.E. Smith), is a cross-crop target pest of Bt corn, Bt cotton, and Bt soybean. This pest, thus far, is the only target pest species that has developed field resistance to Bt crops in multiple areas across countries. Cry2Ab2 is a common Bt protein expressed in transgenic corn and cotton targeting lepidopteran pests including S. frugiperda. The objective of this study was to characterize fitness costs and inheritance of Cry2Ab2 resistance in S. frugiperda. In the fitness cost test, performance of the Cry2Ab2-resistant, -susceptible, and two reciprocal F1 colonies of S. frugiperda was assayed on non-toxic diet and non-Bt corn leaf tissue. Biological parameters measured were 7-day larval weight, neonate-to-pupa development time, neonate-to-pupa survivorship, pupal weight, sex ratio, and egg production. In the inheritance study, larval mortalities of the resistant- and –susceptible parents, and eight other cross-strains were assayed using diet-incorporated and leaf tissue bioassays with Cry2Ab2. Maternal effects were examined by comparing the larval mortalities between the two F1 strains. Dominance levels of resistance were measured by comparing the larval mortalities of resistant, susceptible, and F1 heterozygous strains. Number of genes associated with the resistance was estimated by fitting the observed mortalities of F2 and backcross strains with the Mendelian monogenic inheritance model. There were no significant differences among the four insect strains for all the fitness parameters measured with few exceptions, suggesting that the resistance was not associated with fitness costs. The Cry2Ab2 resistance in S. frugiperda was likely inherited as a single, autosomal, recessive gene. Information generated from this study should be useful in assessing resistance risk and developing management strategies for the sustainable use of Bt crop technology

    Production economics of Ginger (Zingiber officinale Rose.) in Salyan district of Nepal

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    This study investigates the economics of ginger (Zingiber officinale Rose.) production in the Salyan district of Nepal. The production economics was assessed by the household survey in purposively selected Sharada municipality and Siddhakumakh Rural Municipalities. The semi-structured interview schedule was administered to interview randomly selected forty-three producers from Sharada Municipality and thirty-one producers from Siddhakumakh Rural Municipality. The results indicated that the ginger production was found to be a profitable enterprise in the study area with an average B:C ratio of 1.55. The overall productivity of ginger in the study area was found to be 16.28 MT/ha. The Cobb-Douglas production function indicates that ginger production exhibited increasing returns to scale at a decreasing rate. The regression function of 0.784 implies that if all the inputs specified in the production function are increased by 100%, the gross return will increase by about 78.4%

    Response of maize (Zea mays L.) hybrids to different levels of nitrogen

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    Nitrogen is one of the key factors for higher grain production of hybrid maize (Zea mays L.). The use of improved varieties and optimal use of nitrogen (N) fertilizer is important for exploiting yield potential of maize. This work was carried out to evaluate the effects of N rates on grain yield and yield attributing traits of hybrid maize. Two hybrids (RML-86/RML-96 and RML-95/RML-96) and five levels of nitrogen (120, 150, 180, 210 and 240 kg N/ha) were evaluated at research field of National Maize Research Program (NMRP), Rampur, Chitwan, Nepal in spring season of  2017 and 2018. The experiments were conducted in two factorial randomized complete block design (RCBD) with three replications under rainfed condition. The pooled analysis (2017 and 2018) showed that the highest grain yield 10.5 and 10.5 t/ha were given by hybrids RML86/RML96 and RML95/RML96, respectively with the use of 150 kg N/ha in 2017. The hybrids RML-86/RML-96 and RML-95/RML-96 produced the highest grain yield 7.49 and 7.68 t/ha, respectively with the use of 150 kg N/ha in 2018. The mean grain yield (2017 and 2018) showed that both maize hybrids produced the highest grain yield 10.5 t/ha in 2017 and 7.58 t/ha year in 2018 with the application of 150 kg N/ha. The application of nitrogen fertilizer on grain yield was found significant (P<0.05) in both years. Therefore, the application of 150 kg N/ha has significantly increased grain yield of maize, Therefore, this dose of nitrogen can be recommended for higher maize production in Chitwan, Nepal in spring season under rainfed condition

    A Short Note on Linkage of Climatic Records between Terai and Mid-mountain of Central Nepal

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    The steep North to South (N-S) gradient and complex topography markssignificant variations in the spatial and temporal patterns of climatic variation surrounding within a few distances in the Nepal Himalayas. Hence,to validate climatic linkages between the stations under two distinct topographic conditions, the study examines the observational climatic data from 106m a.s.l. and 1801m a.s.l., as a representative station from a plain and hilly area. Different statistical tools including Pearson correlation analysis and a best-fit regression model were applied to analyze climate data. The analysis of 13129 daily average temperature records and 13147 daily total precipitation records showed that the variation in their sum and average of daily, five days, ten days, and monthly values between the stations in the different elevations marked significantly.Despite these variations, temperature records are measured to be consistent in different altitudes and strongly correlated. The precipitation data showed a comparatively weaker correlation. The coefficients (0.85-1.6) with R2 >0.50 in the regression models for the lower elevation and higher elevation station in the mid-mountain region except for the monsoon season. It indicated a similar fluctuation of temperature between these two stations in the respective area. The strong degree of association and the change of climatic parameters in different range and elevations indicate the possibilities of using climatic data from Terai to represent the Mid-mountain region of central Nepal

    Geotechnical Field Reconnaissance: Gorkha (Nepal) Earthquake of April 25, 2015 and Related Shaking Sequence

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    The April 25, 2015 Gorkha (Nepal) Earthquake and its related aftershocks had a devastating impact on Nepal. The earthquake sequence resulted in nearly 9,000 deaths, tens of thousands of injuries, and has left hundreds of thousands of inhabitants homeless. With economic losses estimated at several billion US dollars, the financial impact to Nepal is severe and the rebuilding phase will likely span many years. The Geotechnical Extreme Events Reconnaissance (GEER) Association assembled a reconnaissance team under the leadership of D. Scott Kieffer, Binod Tiwari and Youssef M.A. Hashash to evaluate geotechnical impacts of the April 25, 2015 Gorkha Earthquake and its related aftershocks. The focus of the reconnaissance was on time-sensitive (perishable) data, and the GEER team included a large group of experts in the areas of Geology, Engineering Geology, Seismology, Tectonics, Geotechnical Engineering, Geotechnical Earthquake Engineering, and Civil and Environmental Engineering. The GEER team worked in close collaboration with local and international organizations to document earthquake damage and identify targets for detailed follow up investigations. The overall distribution of damage relative to the April 25, 2015 epicenter indicates significant ground motion directivity, with pronounced damage to the east and comparatively little damage to the west. In the Kathmandu Basin, characteristics of recorded strong ground motion data suggest that a combination of directivity and deep basin effects resulted in significant amplification at a period of approximately five seconds. Along the margins of Kathmandu Basin structural damage and ground failures are more pronounced than in the basin interior, indicating possible basin edge motion amplification. Although modern buildings constructed within the basin generally performed well, local occurrences of heavy damage and collapse of reinforced concrete structures were observed. Ground failures in the basin included cyclic failure of silty clay, lateral spreading and liquefaction. Significant landsliding was triggered over a broad area, with concentrated activity east of the April 25, 2015 epicenter and between Kathmandu and the Nepal-China border. The distribution of concentrated landsliding partially reflects directivity in the ground motion. Several landslides have dammed rivers and many of these features have already been breached. Hydropower is a primary source of electric power in Nepal, and several facilities were damaged due to earthquake-induced landsliding. Powerhouses and penstocks experienced significant damage, and an intake structure currently under construction experienced significant dynamic settlement during the earthquake. Damage to roadways, bridges and retaining structures was also primarily related to landsliding. The greater concentration of infrastructure damage along steep hillsides, ridges and mountain peaks offers a proxy for the occurrence of topographic amplification. The lack of available strong motion records has severely limited the GEER team’s ability to understand how strong motions were distributed and how they correlate to distributions of landsliding, ground failure and infrastructure damage. It is imperative that the engineering and scientific community continues to install strong motion stations so that such data is available for future earthquake events. Such information will benefit the people of Nepal through improved approaches to earthquake resilient design

    Geotechnical Effects of the 2015 Magnitude 7.8 Gorkha, Nepal, Earthquake and Aftershocks

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    This article summarizes the geotechnical effects of the 25 April 2015 M 7.8 Gorkha, Nepal, earthquake and aftershocks, as documented by a reconnaissance team that undertook a broad engineering and scientific assessment of the damage and collected perishable data for future analysis. Brief descriptions are provided of ground shaking, surface fault rupture, landsliding, soil failure, and infrastructure performance. The goal of this reconnaissance effort, led by Geotechnical Extreme Events Reconnaissance, is to learn from earthquakes and mitigate hazards in future earthquakes

    Serotyping and antibiotic susceptibility patterns of Vibrio and Shigella isolates from diarrheal patients visiting a Tropical and Infectious Diseases Hospital in central Nepal

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    Abstract Background Diarrheal diseases are the major infectious disease in developing countries like Nepal. Lack of proper sanitation and antimicrobial resistance gained by microbes have challenged to address diarrheal diseases in resource-limited countries. Early diagnosis of disease and proper antibiotic treatment can significantly reduce the disease burden. This study was designed to determine the recent antimicrobial susceptibility pattern of Vibrio cholerae and Shigella spp. to assure the proper antibiotic treatment. Stool specimens were processed following microbiological protocol and identified by biochemical and serological tests recommended by the Clinical Laboratory Standard Institute. Results Out of total 640 analyzed stool samples, 50 were culture positive, among them 29 were Shigella spp. (64.4%) and 21 were V. cholerae (46.6%). All V. cholerae strains belonged to the serogroup O1 and serovar Ogawa. Among the Shigella spp., Shigella flexneri 17 (59%) topped the list of serotype followed by Shigella sonnei 8 (28%), Shigella dysenteriae 3 (10%) and Shigella boydii 1 (3%) respectively. All the V. cholerae isolates (100%) were sensitive to cefotaxime while 71% were sensitive to tetracycline but 100 and 90.4% were resistance to co-trimoxazole and nalidixic acid respectively. Shigella isolates were mostly susceptible to cefotaxime (97%) while ciprofloxacin (48%) and ofloxacin (55%) were less effective drugs. Conclusions These results on the prevalence of enteropathogens and their antibiotic resistance pattern may help to guide accurate choice of therapy in clinical setting. Hence, development of evidence based National Guidelines for the treatment of diarrhea is needed

    Survey of current materials and impression techniques for Complete Dentures among Nepalese Prosthodontists

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    ABSTRACTBackground: Impression making is one of the critical factors in determining success or failure of complete denture therapy. The precise reproduction of edentulous foundation is essential for retention, stability, and support of the removable prosthesis. Evidence suggests that there is variability in materials and techniques regarding impressions making for complete dentures. There is little published information on studies conducted among Nepalese Prosthodontists. The purpose of this study was to evaluate current materials andmethods for impressions for complete denture prosthodontics in Nepal. Materials &amp; Methods: A questionnaire based survey was conducted among Nepalese Prosthodontists. Ethical approval for the beginning of the study was obtained via Institutional Review Committee, Nepal Medical College. A self-administered anonymous questionnaire was distributed to the participants. Data were analyzed by using frequency distribution.Results: Majority of responses indicated use of irreversible hydrocolloid in stock metal tray for making the preliminary impression. The selective pressure was the predominantly used impression philosophy (78.3%). The most common material for the fabrication of custom trays was autopolymerizing acrylic resin (96.7%). All respondents border molded the custom tray prior to making the final impression. The final impression materials used were zinc oxide eugenol impression paste (73.3%), polyvinylsiloxane (11.7%), polyether (11.7%) and polysulphide (3.3%). Conclusion: Although there is variability in impression materials andtechniques used by Prosthodontists in Nepal for the fabrication of complete dentures, the results showed interesting trends. Most practitioners followed the traditional techniques of complete denture impression procedures.Keywords: complete denture; custom tray; edentulism; impression. </p

    Determinants of Telehealth Service Use among Mental Health Patients: A Case of Rural Louisiana

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    The COVID-19 pandemic decreased the in-person outpatient visits and accelerated the use of telehealth services among mental health patients. Our study investigated the sociodemographic and clinical correlates of the intensity of telehealth use among mental health patients residing in rural Louisiana, United States. The study sample included 7069 telehealth visits by 1115 unique patients encountered from 1 April 2020 to 31 March 2021 at six mental health outpatient clinics managed by the Northeast Delta Human Services Authority (NEDHSA). We performed a negative binomial regression analysis with the intensity of service use as the outcome variable. Being younger, female, and more educated were associated with a higher number of telehealth visits. The prevalence of other chronic conditions increased telehealth visits by 10%. The telehealth service intensity varied across the nature of mental health diagnoses, with patients diagnosed with the schizophrenia spectrum and other psychotic disorders utilizing 15% fewer telehealth visits than patients diagnosed with depressive disorders. The promotion of telehealth services among mental health patients in the rural setting might require the elimination of the digital divide with a particular focus on the elderly, less educated, and those with serious mental health illnesses such as schizophrenia and psychotic disorders
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