108 results on '"Kumar, Amit"'
Search Results
102. Economic analysis of different greenhouse gas mitigation technologies in rice-wheat cropping system of the Indo-Gangetic Plains.
- Author
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Gupta, Dipak Kumar, Bhatia, Arti, Das, T. K., Singh, Parmendra, Kumar, Amit, Jain, Niveta, and Pathak, Himanshu
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GREENHOUSE gas mitigation , *WHEAT , *RICE straw , *SOIL management , *GRASSES - Abstract
To reduce the greenhouse gas (GHG) emission from rice and wheat cultivation several mitigation options have been suggested. However, economic impact of these technologies has been poorly documented. In the present study economic analysis of some emerging GHG mitigation technologies for rice-wheat system of the Indo-Gangetic Plains has been carried out. The experiment consisted of six combinations of wheat- rice crop rotation using eight treatments, including conventionally tilled wheat (CTW), zero tilled wheat (ZTW), transplanted puddled rice (TPR), dry direct seeded rice (DSR), intermittent wetting and drying (IWD), application of rice straw (RS) with ZTW and use of neem oil-coated urea (NOCU) in TPR and ZTW. Cost of various inputs and income from grain and straw were used for computing the benefit to cost (B : C) ratio in the different treatments. ZTW showed higher yield and B : C ratio compared to CTW along with reduction in fuel consumption during tillage operation. In spite of lower yield under DSR and IWD, saving of water, labour and energy in these treatments lowered the cost of cultivation and enhanced B : C ratio similar to TPR. Application of rice straw and NOCU also showed positive impact on crop yield. B : C ratio of rice-wheat system ranged from 1.62 to 1.86 in the first year and from 1.86 to 2.16 in the second year. B : C ratio was significantly higher in all the treatments in the experimented rice-wheat system compared to conventional system, i.e. CTW-TPR. The ZTW + RR - DSR (WR5) showed highest B : C ratiofollowed by ZTW + DSR (WR4) in both the seasons. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
103. Visible Emission Line Coronagraph on Aditya-L1.
- Author
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Prasad, B. Raghavendra, Banerjee, Dipankar, Singh, Jagdev, Nagabhushana, S., Kumar, Amit, Kamath, P. U., Kathiravan, S., Venkata, Suresh, Rajkumar, N., Natarajan, V., Juneja, Madhur, Somu, Pawan, Pant, Vaibhav, Shaji, Nigar, Sankarsubramanian, K., Patra, Asit, Venkateswaran, R., Adoni, Abhijit Avinash, Narendra, S., and Haridas, T. R.
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CORONAGRAPHS , *CORONAL mass ejections , *SOLAR corona , *MAGNETIC field measurements , *SIGNAL-to-noise ratio - Abstract
Solar coronagraph mimics total solar eclipse by blocking the solar disk and enabling the observation of extended coronal atmosphere of the Sun. Visible Emission Line Coronagraph (VELC), on-board Aditya-L1 space mission, is an internally occulted solar coronagraph capable of simultaneous imaging, spectroscopy and spectro-polarimetry close to the solar limb. This payload is designed to study the coronal plasma and heating of the solar corona. Studying development, dynamics and origin of coronal mass ejections and measurement of coronal magnetic fields over active regions are other important science goals. VELC is designed to image the solar corona at 500 nm with an angular resolution of 5" over a field of view (FOV) of 1.05-3 Ro. It also facilitates simultaneous multi-slit spectroscopy at three emission lines, viz. Fe XIV (530.3 nm), Fe XI (789.2 nm) and Fe XIII (1074.7 nm) with a spectral resolution of 28, 31 and 202 mÅ/pixel respectively, over an FOV of 1.05-1.5 Ro. The payload has a dual-beam spectro-polarimetry channel for magnetic field measurements at 1074.7 nm. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
104. Monitoring of glacier changes and response time in Chorabari Glacier, Central Himalaya, Garhwal, India.
- Author
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Mehta, Manish, Dobhal, D. P., Kesarwani, Kapil, Pratap, Bhanu, Kumar, Amit, and Verma, Akshya
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GLACIERS , *ICE formation & growth , *CRYOSPHERE , *SURVEYS - Abstract
Chorabari Glacier (6.6 sq. km) in the Mandakini River basin, a tributary of the River Alaknanda, Central Himalaya, Garhwal (India) has been monitored in terms of its length and frontal area (snout) changes for the period between 1962 and 2012. Global Positioning System, Survey of India toposheet (1 : 50,000) and ground-based measurements were used to obtain the changes in morphology and size of the glacier. The result shows that the frontal area of the glacier has shrunk by 1% and 344 ± 24 m length loss, with an average rate of 6.8 ± 0.5 m a-1 from 1962 to 2012. The observed terminus records of Chorabari Glacier indicate that the positive mass balance can cause terminus advance in about a 17-year timescale. The lag time of glacier signal transferred from accumulation area to the snout by glacier flow is about 562 years. These observations as well as other studies carried out in the region show a significant reduction in glacier area. The increased retreat rate of the glacier snout is probably a direct consequence of global warming. [ABSTRACT FROM AUTHOR]
- Published
- 2014
105. Modelling potential distribution of Sapium sebiferum - an invasive tree species in western Himalaya.
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Jaryan, Vikrant, Datta, Arunava, Uniyal, Sanjay Kr., Kumar, Amit, Gupta, R. C., and Singh, R. D.
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TALLOW tree , *LIFE sciences , *PLANT invasions , *MAXIMUM entropy method ,POTENTIAL distribution - Abstract
The use of species distribution models is gaining popularity in biological sciences. We used Maxent, a maximum entropy-based program, to predict distribution of Sapium sebiferum in western Himalaya. Sapium sebiferum is amongst the highly invasive species of the world and its spread in western Himalaya is a serious conservation issue. In order to model its distribution, we used field-collected coordinates of 177 presence locations of the species. Additionally, environmental data downloaded from the worldclim data portal were also used. Maxent was then run using default settings with 70% of the locations being used for training and the remaining 30% for testing the model. Area under curve for the receiving operator analyses measured at all possible threshold values training (0.993) and test (0.993) was close to 1, thereby showing the accuracy of the model. [ABSTRACT FROM AUTHOR]
- Published
- 2013
106. Long-term ecological and biodiversity monitoring in the western Himalaya using satellite remote sensing.
- Author
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Chawla, Amit, Yadav, Pawan K., Uniyal, Sanjay K., Kumar, Amit, Vats, Surender K., Kumar, Sanjay, and Ahuja, P. S.
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BIODIVERSITY , *REMOTE sensing , *ENVIRONMENTAL monitoring , *ECOTONES , *FOREST plants - Abstract
The IPCC in its Fourth Assessment Report (AR4) described the Himalayan Region as data-deficient in terms of climate monitoring. This is a serious impediment to global research initiatives and thus necessitates long-term ecological monitoring (LTEM) across the Himalaya. Being governed by low temperature conditions, the high-altitude regions in Himalaya are more responsive to changing environmental conditions and hence serve as better indicators. We identified few Protected Areas (PAs) and selected forest core area and ecotones along the temperate, sub-alpine, alpine and cold desert ecosystems in Himachal Pradesh to establish a network of permanent monitoring plots (PMPs). Land and vegetation cover map of three selected PAs has been prepared using Landsat TM satellite data. Among the 10 PMPs, the temperate and tree line forests in the GHNP were found to have the highest tree diversity with Taxus wallichiana showing good stand density and regeneration. The soil pH was found to be higher for cold desert and lower for tree line forests and alpine meadows. Soil total carbon and nitrogen contents ranged from 1.08% to 13.37% and 0.094% to 1.14% respectively. It was observed that the herbs diversity showed a positive trend with increasing soil carbon and nitrogen concentrations. Satellite remote sensing proves to be a useful tool in an LTEM study, including biodiversity assessment and climate change research in complex terrains such as the Himalaya. [ABSTRACT FROM AUTHOR]
- Published
- 2012
107. GENERAL ARTICLES: Proposed visible emission line space solar coronagraph.
- Author
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Singh, Jagdev, Raghavendra Prasad, B., Venkatakrishnan, P., Sankarasubramanian, K., Banerjee, Dipankar, Bayanna, Raja, Mathew, Shibu, Murthy, Jayant, Subramaniam, Prasad, Ramesh, R., Kathiravan, S., Nagabhushana, S., Mahesh, P. K., Manoharan, P. K., Uddin, Wahab, Sriram, S., Kumar, Amit, Srivastava, N., Rao, Koteswara, and Nagendra, C. L.
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CORONAL mass ejections , *CORONAGRAPHS , *SOLAR corona , *WAVELENGTHS , *ATMOSPHERE - Abstract
The outer atmosphere of the sun - called the corona - has been observed during total solar eclipse for short periods (typically < 6 min), from as early as the eighteenth century. In the recent past, space-based instruments have permitted us to study the corona uninterruptedly. In spite of these developments, the dynamic corona and its high temperature (1-2 million K) are yet to be fully understood. It is conjectured that their dynamic nature and associated energetic events are possible reasons behind the high temperature. In order to study these in detail, a visible emission line space solar coronagraph is being proposed as a payload under the small-satellite programme of the Indian Space Research Organisation. The satellite is named as Aditya-1 and the scientific objectives of this payload are to study: (i) the existence of intensity oscillations for the study of wavedriven coronal heating; (ii) the dynamics and formation of coronal loops and temperature structure of the coronal features; (iii) the origin, cause and acceleration of coronal mass ejections (CMEs) and other solar active features, and (iv) coronal magnetic field topology and three-dimensional structures of CMEs using polarization information. The uniqueness of this payload compared to previously flown space instruments is as follows: (a) observations in the visible wavelength closer to the disk (down to 1.05 solar radii); (b) high time cadence capability (better than two-images per second), and (c) simultaneous observations of at least two spectral windows all the time and three spectral windows for short durations. [ABSTRACT FROM AUTHOR]
- Published
- 2011
108. Brainstorming on the future of the highly threatened medicinal plants of the Western Himalaya, India.
- Author
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Mathela, Manisha, Bargali, Himanshu, Sharma, Monika, Sharma, Rupali, and Kumar, Amit
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MEDICINAL plants , *POACHING , *PLANT conservation , *BIOLOGICAL extinction , *NATURAL resources - Abstract
The article presents information related to the brainstorming on the future of the highly threatened medicinal plants of the Western Himalaya, India. It mentions that the Himalayan ecosystems are a hotspot of biodiversity; and also regulate climate and provide livelihoods to several people. It also mentions about the assessment of medicinal and aromatic plant (MAP) species, including their collection, usage, demand, market, price trend and life cycle.
- Published
- 2020
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