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Search Results: 1 - 10 of 1263 matches for " Subhojit Datta "
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Conventional and Molecular Approaches towards Genetic Improvement in Pigeonpea for Insects Resistance  [PDF]
Arbind K. Choudhary, Ranjeet Sharad Raje, Subhojit Datta, Rafat Sultana, Timmanna Ontagodi
American Journal of Plant Sciences (AJPS) , 2013, DOI: 10.4236/ajps.2013.42A049
Abstract:
Pigeonpea [Cajanus cajan (L.) Millspaugh] is an important food legume of the semi-arid tropics (SAT) sustaining livelihood of millions of people. Stagnant and unstable yield per hectare all over the world is the characteristic feature of this crop. This is primarily ascribed to its susceptibility/sensitivity to a number of biotic and abiotic factors. Among biotic factors, insects such as pod borer (Helicoverpa armigera), pod fly (Melanoagromyza obtusa) and spotted borer (Maruca vitrata) substantially damage the crop and result in significant economic losses. Management of these insects by genetic means has always been considered environment friendly approach. However, genetic improvement has always been impeded by limited genetic variability in the primary gene pool of pigeonpea. Wild species present in the secondary and tertiary gene pools have been reported to carry resistance for such insects. However, transfer of resistance through conventional backcrossing has not been much successful. It calls for gene introgression through marker assisted backcrossing (MABC) or advanced backcross breeding (AB breeding). In this review, we have attempted to assess the progress made through conventional and molecular breeding and suggested the ways to move further towards genetic enhancement for insects resistance in pigeonpea
Mapping of Mungbean Yellow Mosaic India Virus (MYMIV) and powdery mildew resistant gene in black gram [Vigna mungo(L.) Hepper]
Tuba Anjum,K. Sanjeev Gupta and Subhojit Datta
Electronic Journal of Plant Breeding , 2010,
Abstract: Black gram, one of the important species of Asian Vigna group of grain legumes, is widely grown in South Asia and is animportant source of dietary protein. The two main biological constraints particularly Mungbean Yellow Mosaic IndiaVirus(MYMIV) and powdery mildew pose a major threat to black gram production in India. Several reports on mappingmungbean yellow mosaic virus disease and powdery mildew resistant genes on black gram using parental lines suitable forcountries viz. Australia and Japan are available. However, to achieve precision in plant breeding, it is important that mappingof traits are done using parental lines which are best suited for the target area/country. Microsatellite markers facilitateeffective screening of mapping population and marker assisted selection for target traits such as disease resistance in manycrops. Linkage mapping for identification of genes conferring resistance to these target traits in the crop is underway. Theparents selected for MYMIV mapping population are DPU 88-31 as resistant source and AKU 9904 as susceptible one. Forestablishment of powdery mildew mapping population RBU 38 was used as resistant and DPU 88-31 as the susceptible one.Parental polymorphism was assessed using 363 SSR and 24 RGH markers. Efforts are being made to identify the markerstightly linked to the genes responsible for resistance which will be useful for marker assisted breeding for developingMYMIV and powdery mildew resistant cultivars in black gram.
Genetic Diversity in Selected Indian Mungbean [Vigna radiata (L.) Wilczek] Cultivars Using RAPD Markers  [PDF]
Subhojit Datta, Sarika Gangwar, Shiv Kumar, Sanjeev Gupta, Rita Rai, Mayank Kaashyap, Pallavi Singh, Sushil Kumar Chaturvedi, Brij Bhuvan Singh, Nagaswamy Nadarajan
American Journal of Plant Sciences (AJPS) , 2012, DOI: 10.4236/ajps.2012.38130
Abstract: Random amplified polymorphic DNA (RAPD) markers were used to study the DNA polymorphism in Indian mungbean cultivars. A total of 60 random primers were used in the study and 33 of them generated reproducible RAPD patterns. Amplification of genomic DNA of most popular 24 Indian mungbean cultivars with these RAPD primers yielded 249 fragments that could be scored, of which 224 were polymorphic, with an average of 7.0 polymorphic fragments per primer. Number of amplified fragments with random primers ranged from 2 (OPI 9) to 17 (OPD 7). Percentage polymorphism ranged from 33% (OPX 5) to a maximum of 100% (OPX 4, OPX 6, OPX 13, OPX 15, OPX 19, OPD 5, OPD 7, OPD 20, OPI 4, OPI 6, OPI 13, OPI 14, OPI 18 and OPF 1), with an average of 90%. The Jaccard’s similarity indices based on RAPD profiles were subjected to UPGMA cluster analysis. And genotypes grouped in two major groups. Sixteen out of 24 released cultivars grouped to cluster I. This indicated the narrow genetic base in the Indian mungbean cultivars used in the study. The details of diversity analysis and possible reasons for narrow genetic base in mungbean cultivars are discussed in the present study.
Compressive Imaging using Approximate Message Passing and a Markov-Tree Prior
Subhojit Som,Philip Schniter
Computer Science , 2011, DOI: 10.1109/TSP.2012.2191780
Abstract: We propose a novel algorithm for compressive imaging that exploits both the sparsity and persistence across scales found in the 2D wavelet transform coefficients of natural images. Like other recent works, we model wavelet structure using a hidden Markov tree (HMT) but, unlike other works, ours is based on loopy belief propagation (LBP). For LBP, we adopt a recently proposed "turbo" message passing schedule that alternates between exploitation of HMT structure and exploitation of compressive-measurement structure. For the latter, we leverage Donoho, Maleki, and Montanari's recently proposed approximate message passing (AMP) algorithm. Experiments with a large image database suggest that, relative to existing schemes, our turbo LBP approach yields state-of-the-art reconstruction performance with substantial reduction in complexity.
Genetic Patterns of Domestication in Pigeonpea (Cajanus cajan (L.) Millsp.) and Wild Cajanus Relatives
Mulualem T. Kassa, R. Varma Penmetsa, Noelia Carrasquilla-Garcia, Birinchi K. Sarma, Subhojit Datta, Hari D. Upadhyaya, Rajeev K. Varshney, Eric J. B. von Wettberg, Douglas R. Cook
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0039563
Abstract: Pigeonpea (Cajanus cajan) is an annual or short-lived perennial food legume of acute regional importance, providing significant protein to the human diet in less developed regions of Asia and Africa. Due to its narrow genetic base, pigeonpea improvement is increasingly reliant on introgression of valuable traits from wild forms, a practice that would benefit from knowledge of its domestication history and relationships to wild species. Here we use 752 single nucleotide polymorphisms (SNPs) derived from 670 low copy orthologous genes to clarify the evolutionary history of pigeonpea (79 accessions) and its wild relatives (31 accessions). We identified three well-supported lineages that are geographically clustered and congruent with previous nuclear and plastid sequence-based phylogenies. Among all species analyzed Cajanus cajanifolius is the most probable progenitor of cultivated pigeonpea. Multiple lines of evidence suggest recent gene flow between cultivated and non-cultivated forms, as well as historical gene flow between diverged but sympatric species. Evidence supports that primary domestication occurred in India, with a second and more recent nested population bottleneck focused in tropical regions that is the likely consequence of pigeonpea breeding. We find abundant allelic variation and genetic diversity among the wild relatives, with the exception of wild species from Australia for which we report a third bottleneck unrelated to domestication within India. Domesticated C. cajan possess 75% less allelic diversity than the progenitor clade of wild Indian species, indicating a severe “domestication bottleneck” during pigeonpea domestication.
What does the mediodorsal thalamus do?
Anna S. Mitchell,Subhojit Chakraborty
Frontiers in Systems Neuroscience , 2013, DOI: 10.3389/fnsys.2013.00037
Abstract: Dense amnesia can result from damage to the medial diencephalon in humans and in animals. In humans this damage is diffuse and can include the mediodorsal nuclei of the thalamus. In animal models, lesion studies have confirmed the mediodorsal thalamus (MD) has a role in memory and other cognitive tasks, although the extent of deficits is mixed. Anatomical tracing studies confirm at least three different subgroupings of the MD: medial, central, and lateral, each differentially interconnected to the prefrontal cortex (PFC). Moreover, these subgroupings of the MD also receive differing inputs from other brain structures, including the basal ganglia thus the MD subgroupings form key nodes in interconnected frontal-striatal-thalamic neural circuits, integrating critical information within the PFC. We will provide a review of data collected from non-human primates and rodents after selective brain injury to the whole of the MD as well as these subgroupings to highlight the extent of deficits in various cognitive tasks. This research highlights the neural basis of memory and cognitive deficits associated with the subgroupings of the MD and their interconnected neural networks. The evidence shows that the MD plays a critical role in many varied cognitive processes. In addition, the MD is actively processing information and integrating it across these neural circuits for successful cognition. Having established that the MD is critical for memory and cognition, further research is required to understand how the MD specifically influences these cognitive processing carried out by the brain.
Sparsity Pattern Recovery in Bernoulli-Gaussian Signal Model
Subhojit Som,Lee C Potter
Mathematics , 2010,
Abstract: In compressive sensing, sparse signals are recovered from underdetermined noisy linear observations. One of the interesting problems which attracted a lot of attention in recent times is the support recovery or sparsity pattern recovery problem. The aim is to identify the non-zero elements in the original sparse signal. In this article we consider the sparsity pattern recovery problem under a probabilistic signal model where the sparse support follows a Bernoulli distribution and the signal restricted to this support follows a Gaussian distribution. We show that the energy in the original signal restricted to the missed support of the MAP estimate is bounded above and this bound is of the order of energy in the projection of the noise signal to the subspace spanned by the active coefficients. We also derive sufficient conditions for no misdetection and no false alarm in support recovery.
Exterior Sourcing and Technology Distinctness as Indicators for Radical Innovations: Evidence from Patents in Information Technology Industry  [PDF]
Avimanyu Datta
Technology and Investment (TI) , 2011, DOI: 10.4236/ti.2011.23020
Abstract: We hypothesized and tested the role of looking beyond a firm’s focal industry on technology distinctness and both of their impacts on radicalness of innovations. We used patent filings from 1996 through 2009 (N = 192,070) from the IT industry within the S & P-500 database. We also classified exterior sourcing as high and low, and divided technology distinctness as high, medium, and low. We found that when innovations are primarily sourced exteriorly, there is a negative relationship with technology distinctness. We also found that the relationship between technology distinctness and radicalness is stronger at lower levels of exterior sourcing than at higher levels. Further, when exterior sourcing is unable to create highly distinct technologies, the relationship between technology distinctness and radicalness goes from sparsely significant to significantly negative.
Application of Bootstrap in Dose Apportionment of Nuclear Plants Via Uncertainty Modeling of the Effluent Released from Plants  [PDF]
Debabrata Datta
World Journal of Nuclear Science and Technology (WJNST) , 2012, DOI: 10.4236/wjnst.2012.21007
Abstract: Nuclear power plants are always operated under the guidelines stipulated by the regulatory body. These guidelines basically contain the technical specifications of the specific power plant and provide the knowledge of the discharge limit of the radioactive effluent into the environment through atmospheric and aquatic route. However, operational constraints sometimes may violate the technical specification due to which there may be a failure to satisfy the stipulated dose apportioned to that plant. In a site having multi facilities sum total of the dose apportioned to all the facilities should be constrained to 1 mSv/year to the members of the public. Dose apportionment scheme basically stipulates the limit of the gaseous and liquid effluent released into the environment. Existing methodology of dose apportionment is subjective in nature that may result the discharge limit of the effluent in atmospheric and aquatic route in an adhoc manner. Appropriate scientific basis for dose apportionment is always preferable rather than judicial basis from the point of harmonization of establishing the dose apportionment. This paper presents an attempt of establishing the discharge limit of the gaseous and liquid effluent first on the basis of the existing value of the release of the same. Existing release data for a few years (for example 10 years) for any nuclear power station have taken into consideration. Bootstrap, a resampling technique, has been adopted on the existing release data sets to generate the corresponding population distribution of the effluent release. Cumulative distribution of the population distribution obtained is constructed and using this cumulative distribution, 95th percentile (upper bound) of the discharge limit of the radioactive effluents is computed. Dose apportioned for a facility is evaluated using this estimated upper bound of the release limit. Paper de- scribes the detail of the bootstrap method in evaluating the release limit and also presents the comparative study of the dose apportionment using this new method and the existing adhoc method.
Construction of Zero Autocorrelation Stochastic Waveforms  [PDF]
Somantika Datta
Advances in Pure Mathematics (APM) , 2012, DOI: 10.4236/apm.2012.26065
Abstract: Stochastic waveforms are constructed whose expected autocorrelation can be made arbitrarily small outside the origin. These waveforms are unimodular and complex-valued. Waveforms with such spike like autocorrelation are desirable in waveform design and are particularly useful in areas of radar and communications. Both discrete and continuous waveforms with low expected autocorrelation are constructed. Further, in the discrete case, frames for Cd are constructed from these waveforms and the frame properties of such frames are studied.
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