5,872 research outputs found
Scientometric portrait of Ram Gopal Rastogi
No full textPublication productivity of Indian scientist (R.G. Rastogi) has been documented.
Scientometric analysis of 312 papers by Ram Gopal Rastogi published during 1954 to 1992 in various domains: (a) Luni -solar activity and quiet -time E & F- region (57); (b) Equatorial electric field and low and mid latitude iof:osphere (78); (c) Ionospheric E- region irregularities (19); (dj Ionospheric F- region irregularities (32); and (e) Magnetic disturbance effects on the equatorial low and mid latitude ionosphere (23) were analysed. Interdomainery contents and of the number of papers: a+b were 36; b+c and b+d were 20 each; b+e were 16;. c+e were 5; a+e were 3; d+e were 2; and a+d had only one publication. Highest collaborations were with H. Chandra (61), M.R. Deshpande (42), and G. Sethia (19) out of his total 97 collaborators. His highest productivity was during 1978 with 28 papers followed by 19 papers during 1977. The core journals preferred by him for publishing papers were: Indian Journal of Radio & Space Physics, India, and Journal of Atomic & Terrestrial Physics, UK (59 each), followed by Proceedings of the Indian Academy of Sciences, India (34). Most prolific title keywords with their frequencies were: Ionosphere (92); Equatorial (61); F-region (53); Equatorial electrojet region (40), and Magnetic equator (30)
Biodiversity in Wetlands: assessment, function and conservation. Vol. 1
No full textPreface (B. Gopal, W.J. Junk, J.A. Davis) Biodiversity in wetlands: an introduction. B. Gopal, W.J.Junk The importance of stream-wetland-systems for biodiversity. K.M. Wantzen, W.J. Junk Riverine wetlands and biodiversity conservation in tropical Asia. D. Dudgeon Fish biodiversity in floodplains and their associated rivers. R.L. Welcomme Biodiversity in high Paran River floodplain. A.A. Agostinho, S.M. Thomaz, C.V. Minte-Vera, K.O. Winemiller Mechanisms for development and maintenance of biodiversity in neotropical floodplains. W.J. Junk Biodiversity of a Danubian floodplain: structural, functional and compositional aspects. K. Tockner, C. Baumgartner, F. Schiemer, J.V. Ward Determinants of avian diversity in neotropical mangrove forests. G. Lefebrvre, B. Poulin Biodiversity in wetlands of dry regions. L. Brendonck, W.D. Williams Floristic diversity inthe Okavango Delta, Botswana as an endogenous product of biological activity. W.N. Ellery, T.S. McCarthy, J.M. Dangerfield Karst wetlands biodiversity and continuity through major climatic change: an example from arid tropical Western Australia. W.F. Humphreys Biodiversity of Estonian wetlands. V. Masing, J. Paal, A. Kuresoo Bacterial biodiversity in wetlands. P.I. Boon Restoration of biodiversity to costal and inland wetlands. J.B. Zedler International mechanisms for the conservation and sustainable use of wetlands. D.M.Bartle
Governor of W. B. Mr. Gopal Krishna Gandhi visited IACS during 2007
No full textThe governor of W. B. Mr. Gopal Krishna Gandhi visited IACS during 2007. He and the Director Prof. D. Mukherjee had visited IACS library to see an archival exhibition
Structural And Biophysical Analysis Of The Regulatory Mechanism Of Mycobacterium Tuberculosis Sigma Factors
No full textMycobacterium tuberculosis has one ribosomal RNA operon. The survival of this bacillus thus depends on a transcription mechanism that can effectively couple gene expression to changes in the environment. σ factors are transcription proteins that bind to the RNA polymerase (RNAP) and dictate gene expression. Extra Cytoplasmic Function σ factors (ECF) are a subset of σ factors that coordinate environment-induced changes in transcription. The environment specific binding of ECF σ factors to the RNAP presents an effective mechanism for the bacillus to modulate gene expression. ECF σ factors, in turn, are regulated by their interaction with an anti-σ factor. The active σ factor is released from this complex upon specific cellular or environmental stimuli. The aim of this study was to understand the structural and mechanistic aspects of σ factor activation. Towards this goal, two ECF σ factors, σC and σL, were examined. Structural and biophysical studies on M. tuberculosis σC provided a novel insight into ECF σ factor regulation. Inter-domain interactions in σC were sufficient to occlude the DNA recognition regions even in the absence of an interacting protein. The structure of M. tuberculosis σL in complex with the anti-σ factor RslA provides a structural basis to rationalize the release of active σL under oxidative stress. The other chapters of this thesis include a description of the structure and biochemical features of a hypothetical protein Rv2704 that is co-transcribed with the primary σ factor σA. In an effort to understand the collaboration-competition-redundancy model of prokaryotic σ factors, we performed a computational analysis of this system compiling experimental data from the E. coli and B. subtilis model systems. These results are also presented in this thesis. Put together, the structural and biochemical characteristics of the σ factors presented in this thesis suggest substantial variations in the regulatory mechanisms of the M. tuberculosis σ factors when compared to the canonical E. coli or B. subtilis model systems.
This thesis is organized as follows:
Chapter 1: The introductory chapter of this thesis is organized to frame the pertinent mechanistic issues involved in the σ factor-regulatory protein interactions in the context of the underlying biology of M. tuberculosis. The first part of this chapter provides an overview of σ factors and a summary of the classification of these proteins and their roles in different prokaryotes. The latter part of this chapter is a summary of the pathogen M. tuberculosis in terms of its genetic composition, gene expression as well as aspects of virulence and pathogenecity.
Chapter 2: This chapter describes the characterization of the ECF σ factor, σC. Here we report the structure of an ECF σ factor σC from M. tuberculosis. σC is essential for the lethality of M. tuberculosis in a mouse model of infection. Our studies suggest that M. tuberculosis σC differs from the canonical ECF σ factors as it has an N-terminal domain comprising of 126 amino acids that precedes the σC2 and σC4 domains. In an effort to understand the regulatory mechanism of this protein, the crystal structures of the σC2 and C4 domains of σC were determined. These promoter recognition domains are structurally similar to the corresponding domains of E. coli σA despite the low sequence similarity. Fluorescence experiments using the intrinsic tryptophan residues of σC2 as well as surface plasmon resonance measurements reveal that the σC2 and σC4 domains interact with each other. Mutational analysis suggests that the Pribnow box-binding region of σC2 is involved in this inter-domain interaction. Interactions between the promoter recognition domains in M. tuberculosis σC are thus likely to regulate the activity of this protein even in the absence of an anti-σ factor.
Chapter 3 provides an account of the regulatory features of the ECF σ factor, σL. ECF σ factors are often regulated by their interactions with an anti-σ factor that can sense diverse environmental stimuli. Transcriptional responses to changes in the oxidation state are particularly important for M. tuberculosis as it adapts to the environment of the host alveoli and macrophages. Here we demonstrate that the protein RslA binds Zinc and can sequester σL in a reducing environment. Our data suggests that the cytosolic domain at the N-terminus of RslA alone is involved in binding σL. Under oxidizing conditions, the σL/RslA complex undergoes substantial conformational rearrangements that coincide with the release of the Zinc cofactor. In the absence of Zinc, the affinity of RslA for σL reduces by ca 8 fold compared to the holo form. The CXXC motif of RslA acts as a redox sensor. In response to oxidative stimuli, the proximal cysteines in this motif can form a disulfide bond with the release of the bound Zn2+ ion. This observation could be rationalized based on the crystal structure of the σL4/RslA complex. Put together, RslA is a distinct variant of the Zinc binding anti-σ factor (ZAS) family. The structural and biophysical parameters that control σL/RslA interactions demonstrate how variations in the rate of Zinc release and associated conformational changes in RslA could regulate the release of free σL in a measured response to oxidative stress.
Chapter 4 is based on the biochemical and structural characterization of a hypothetical protein Rv2704. The gene for M. tuberculosis Rv2704 is located in the same operon as the principal σ factor σA. The biochemical and structural features of Rv2704 were thus examined to identify its role, if any, in the regulation of σA. This protein is a trimer in solution and adopts a chorismate mutase-like fold. The crystal structure reveals that Rv2704 is a member of the functionally diverse YjgF family of proteins. The important structural differences between Rv2704 and other YjgF proteins lie in the arrangement of secondary structural elements and the putative functional clefts between the subunit interface. Although Rv2704 does not interact with σA in vitro, the structural similarities to the YjgF family suggests that this protein could interact with a variety of metabolites, potentially influencing its function.
Chapter 5 of this thesis is based on a computational analysis of σ factors. Four conformational segments of σ factors, referred to as σ1, σ2, σ3 and σ4 interact with specific regions of promoter DNA. ECF σ factors are a subset of σ factors that coordinate environment-induced transcription. ECF σ factors are minimalist σ factors with two DNA binding domains viz., σ2 and σ4 that recognize the –10 and –35 promoter elements and are unable to interact with either upstream-activating regions or the extended –10 element of the promoter. There are several ECF σ factors in a typical bacterium often characterized by substantial overlap in function. Here we present an analysis of B. subtilis ECF σ factors and their cognate promoters to understand functional overlap and redundancy in this class of proteins. As expected, conserved bases in the –10 element appear more critical for promoter selectivity than the –35 element. However, we note distinct conformational features in the –35 promoter interaction with the helix-turn-helix (HTH) motif when compared to a data-set of known HTH-DNA complexes. Furthermore, we note differences in –35 element interaction between σ factors that act alone and those that overlap in function. The σ factor promoter interactions were then examined vis-à-vis the estimated cellular concentration of these proteins and their affinity to bind the core RNAP. Put together, this analysis suggests that while the cellular protein concentration dictates the choice of an ECF σ factor to form a complex with the RNAP, conformational features of the –35 element serve to select potential collaborative members, a subset of which eventually initiate transcription. Collaborative arrangements and functional redundancy in ECF σ factors are thus possible within the limits placed by these two parameters.
Chapter 6 is a summary of the work reported in this thesis and the conclusions that can be drawn based on these studies.
The appendix section of this thesis comprises of technical details that were not included in the main text of this thesis. Appendix I describes the initial characterization of the M. tuberculosis σD/anti-σD complex. Appendix II provides the experimental protocols as well as some of the supplementary data to the work reported in Chapters 2-5 of this thesis
Biodiversity in wetlands: assessment, function and conservation. Vol. 2
No full textVol. 2 Preface Biodiversity of the French river Rhône and its floodplain: current state, historical changes and restoration potential Jean-François Fruget and Jean-Louis Michelot Biodiversity changes in the lower Danube river system A. Vadineanu, S. Cristofor and V. Iordache Plant diversity of fen landscapes in the Netherlands Jos T.A. Verhoeven and Roland Bobbink Factors influencing biodiversity in coastal plain wetlands of Southwestern Australia Jenny A. Davis, Stuart A. Halse and Ray H. Froend Wetlands of East Africa: biodiversity, exploitation and policy perspectives Lauren J. Chapman, J. Balirwa, F.W.B. Bugenyi, C. Chapman and T.L. Crisman Biodiversity and conservation of afrotropical wetland invertebrates Nic. Pacini and David M. Harper Diversity in some tropical wetland systems of South America Juan José Neiff Biodiversity in the pantanal wetland, Brazil Carolina Joana da Siva, Karl Matthias Wantzen, Cátia Nunes da Cunha and Francisco de Arruda Machado Biodiversity and management of Keoladeo National Park (India) - a wetland of International importance Malavika Chauhan and Brij Gopal South Asian wetlands and their biodiversity: the role of monsoons Brij Gopal and Malavika Chauhan Assessment, determinants, function and conservation of biodiversity in wetlands: present staus and future needs Brij Gopal and W.J. Jun
コウホシュ キジュツ ゲンゴ カクチョウ Gopal ヲ モチイタ イゴ プログラム ノ シサク
No full text囲碁のパターン知識を記述するための言語Gopalを、定石などの一連の手順や手順の分岐、手抜きなどを記述しやすいように拡張した‘ 拡張Gopal' を定義し、実際にその実行系を実現した。この拡張Gopalの実行系を用いて、箇碁プ口グラムを作成中である。一方、この囲碁プ口グラムが行う探索の方法として、探索の深さが一定でなく、真の値の存在する範囲の上下限をノードの値として使用するB*サーチアルゴリズムを採用し、現在実現中である。拡張Gopa1 実行系が出力する候補手をB*サーチアルゴリズムで探索することにより、探索の回数を少なくなり、深い先読みができると考えている。また、探索の際に使用する評価関数についても試作している。Gopal is a language for describing pattern knowledge of Go. We have extended Gopal so that we can easily describe a sequence of moves such as Jyoseki. Using extend Gopal， branches of Jyoseki and Tenuki are also described easily. We have actual implemented extended Gopal processor which outputs candidate moves for a pattern of the Go board. We are developing an experimental Go program which includes the extended Gopal processor、As a search algorithm for the next move， B* search has been implemented. The candidate moves generated by the extended Gopal processor are only investigated precisely by B*search. We are developing evaluation function used with then B* search
Scientometric analysis of synchronous references in the Physics Nobel lectures, 1981-1985 : a pilot study
No full textScientometric analysis of synchronous references in the nine Physics Nobel lectures by Nicolaas Bloembergen (1981), Arthur L. Schawlow (1981), Kai M. Siegbahn (1981), Kenneth G. Wilson (1982), Subrahmanyan Chandrasekhar (1983), William A. Fowler (1983), Carlo Rubbia (1984), Simon van der Meer (1984), and Klaus von Klitzing (1985) indicated high variations: No. of Synchronous References ranged from 24 (Meer) to 283 (Siegbahn); Synchronous Self-References ranged from 5 (Rubbia) to 88 (Siegbahn); synchronous references to others ranged from 10 (Chandrasekhar) to 255 (Wilson); Synchronous Self-Reference Rates ranged from 6.66 % (Rubbia) to 65.51 % (Chandrasekhar); Single-Authored References ranged from 15 (Klitzing) to 160 (Wilson); Multi-Authored References ranged from 4 (Chandrasekhar) to 194 (Siegbahn); Collaboration Coefficient in the synchronous references ranged from 0.14 (Chandrasekhar) to 0.75 (Klitzing); and Recency (age of 50 % of the latest references) ranged from 2 (Klitzing) to 18 (Chandrasekhar) years. Seventy five per cent of the references belonged to journal articles. Highly referred journals were Astrophysical Journal, Physical Review B, Physical Review Letters, Arkiv Fuer Fysik, Surface Science, Physics Letters, and IEEE Transactions on Nuclear Science.
See: Scientometrics Vol. 61 No.1, pp.55-68
ICAS:MP Lecture by Niraja Gopal Jayal (Jawaharlal Nehru University)
No full textChair: Kalpana Kannabiran (Council for Social Development, Hyderabad) 23 September 2019 Venue: CSDS, Seminar Room, 6 pm – 8 pm Niraja Gopal Jayal is Professor at the Centre for the Study of Law and Governance at the Jawaharlal Nehru University, New Delhi. Her book Citizenship and its Discontents (Harvard University Press, 2013) won the Ananda Kentish Coomaraswamy Prize for 2015. She is also the author of Representing India: Ethnic Diversity and the Governance of Public Institutions (Palgrave ..
The Physics of E×B-Drifting Jets
No full textAbstract. E×B-drifting jets have been generally ignored for the past 25 years even though they may well describe all the astrophysical jet sources, both on galactic and stellar scales. Here we present closed-form solutions for their joint field-and-particle distribution, argue that the observed jets are near equipartition, with extremely relativistic, monoenergetic e±-pairs of bulk Lorentz factor γ < ∼ 104, and are first-order stable. We describe plausible mechanisms for the jets ’ (i) formation, (ii) propagation, and (iii) termination. Wherever a beam meets with resistance, its frozen-in Poynting flux transforms the delta-shaped energy distribution of the pairs into an almost white power law, E2NE ∼ E− with > ∼ 0, via single-step falls through the huge convected potential. Key words. Jet sources—monoenergetic beams—E × B-drift—unified scheme. 1. Background Pair-plasma jets with ultra-relativistic bulk motion have been proposed twenty-five years ago by one of us (Kundt 1979), then jointly elaborated by us (Kundt & Gopal-Krishna 1980). They were also proposed by Morrison (1981), but have usually no
ASIP data-plane processor for multi-standard wireless protocol processing
No full textEvolving Multi-Protocol Multi-Band Software Defined Radio (SDR) devices aim at supporting multiple protocols seamlessly and efficiently. The design of such radios necessitates flexibility in physical layer processing, flexibility in routing packets through processing engines and flexibility in radio frequency reception/transmission. This dissertation addresses an efficient implementation of flexible physical layer processing (PHY) for Interleaving, De-Interleaving and linear Minimum Mean Square Error (MMSE) detection in Multiple Input Multiple Output (MIMO) receivers through Application Specific Instruction Set Processors (ASIPs). The thesis defines and develops a WINLAB cognitive radio (WiNC2R) compatible data-plane ASIP architecture along with suitable hardware-software partitioning of the Processing Engine unit. Given the requirement of very significant design time and the lack of the flexibility after design, dedicated ASIC for PHY may not be a viable option although it has the best performance among all available options. The software application running on general purpose processor cannot satisfy the throughput requirements of the wireless standards. ASIPs provide a better trade-off between flexibility and performance, with the advantage of considerably lower design time than ASICs. We design an efficient multi-standard (802.11a, 802.16e/m) supporting Interleaver/De-Interleaver ASIP, satisfying the throughput requirements for all the modulation-schemes/data-rates in both of the standards. It can be programmed to scale for supporting future wireless standards (that use Block Interleaving/De-Interleaving). We also study viability of a flexible MIMO MMSE detector ASIP supporting variable MR (Number of receiving antennas) * MT (Number of transmitting antennas) operations. We have analyzed the implementation of an hardware-centric algorithm for MIMO detection on an ASIP and also improved its performance with the help of techniques such as fixed point implementation, Single Instruction Multiple Data (SIMD) and Very Long Instruction Word (VLIW). Analysis of the design performance results for MIMO ASIP indicates the limitations of hardware-implementation-specific algorithms on ASIP. We also provide the account of design decisions such as custom ports, memory interfaces and registers that are added to the data-plane processor ASIPs in order to substitute them for dedicated hardware engines in the WiNC2R platform.M.S.Includes bibliographical referencesby Mohit Gopal Wan
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