6,989 research outputs found

    Growth and Persistence of Large Business Groups in India

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    The international business literature is belatedly recognizing the significance of large family-controlled business groups in emerging markets. Most research has focused on analyzing the impact of concentrations of private wealth on economic development in home countries using panel data. This paper examines the growth and persistence of business groups since 1951 in one country – India. Since Independence, the government has attempted to operate an economic policy framework that had, amongst its prime objectives, the curbing of the tendency of business groups to concentrate economic power. As their growth was seen as synonymous with concentration of wealth, business groups became obvious candidates for regulation. Various policy instruments were introduced, such as the Industries (Development and Regulation) (IDR) Act 1951 and the Monopolies and Restrictive Trade Practices (MRTP) Act 1969, with the aim of erecting barriers to their growth. In 1991, economic reform ushered in the removal of the legislative barriers to business group growth. The analysis in this paper concludes that large business groups expanded their share of wealth between 1951 and 1969, but this growth was arrested between 1970 and 1990, and since 1991, it has dwindled. The pre-eminent position of Tata and Birla, as the two largest business groups, remained unchallenged from 1951 until the emergence of the Reliance Group in the late 1990s. However, there has been frequent change in the relative positions of other groups in and out of the Top-20. After economic liberalisation accelerated from 1991, there was significant change in the ranks of business groups in the Top-20. Existing smaller groups or newly emerging groups, particularly in the IT and telecommunications sectors, have replaced many of the previously dominant older groups. This is interpreted as indicating the central role of entrepreneurship in combination with technological innovation, and the opening up of the Indian economy to international competition, in disturbing established business hierarchies in India. More generally, policy intervention appears to have been less effective in breaking up concentrations of economic power in India than economic liberalization and increased competition

    Nuclear thermal propulsion transportation systems for lunar/Mars exploration

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    Nuclear thermal propulsion technology development is underway at NASA and DoE for Space Exploration Initiative (SEI) missions to Mars, with initial near-earth flights to validate flight readiness. Several reactor concepts are being considered for these missions, and important selection criteria will be evaluated before final selection of a system. These criteria include: safety and reliability, technical risk, cost, and performance, in that order. Of the concepts evaluated to date, the Nuclear Engine for Rocket Vehicle Applications (NERVA) derivative (NDR) is the only concept that has demonstrated full power, life, and performance in actual reactor tests. Other concepts will require significant design work and must demonstrate proof-of-concept. Technical risk, and hence, development cost should therefore be lowest for the concept, and the NDR concept is currently being considered for the initial SEI missions. As lighter weight, higher performance systems are developed and validated, including appropriate safety and astronaut-rating requirements, they will be considered to support future SEI application. A space transportation system using a modular nuclear thermal rocket (NTR) system for lunar and Mars missions is expected to result in significant life cycle cost savings. Finally, several key issues remain for NTR's, including public acceptance and operational issues. Nonetheless, NTR's are believed to be the 'next generation' of space propulsion systems - the key to space exploration

    Image-based Quantification of 3D Morphology for Bifurcations in the Left Coronary Artery: Application to Stent Design

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    Background Improved strategies for stent‐based treatment of coronary artery disease at bifurcations require a greater understanding of artery morphology. Objective We developed a workflow to quantify morphology in the left main coronary (LMCA), left anterior descending (LAD), and left circumflex (LCX) artery bifurcations. Methods Computational models of each bifurcation were created for 55 patients using computed tomography images in 3D segmentation software. Metrics including cross‐sectional area, length, eccentricity, taper, curvature, planarity, branching law parameters, and bifurcation angles were assessed using open‐sources software and custom applications. Geometric characterization was performed by comparison of means, correlation, and linear discriminant analysis (LDA). Results Differences between metrics suggest dedicated or multistent approaches should be tailored for each bifurcation. For example, the side branch of the LCX (i.e., obtuse marginal; OM) was longer than that of the LMCA (i.e., LCXprox) and LAD (i.e., first diagonal; D1). Bifurcation metrics for some locations (e.g., LMCA Finet ratio) provide results and confidence intervals agreeing with prior findings, while revised metric values are presented for others (e.g., LAD and LCX). LDA revealed several metrics that differentiate between artery locations (e.g., LMCA vs. D1, LMCA vs. OM, LADprox vs. D1, and LCXprox vs. D1). Conclusions These results provide a foundation for elucidating common parameters from healthy coronary arteries and could be leveraged in the future for treating diseased arteries. Collectively the current results may ultimately be used for design iterations that improve outcomes following implantation of future dedicated bifurcation stents

    Doming Modes and Dynamics of Model Heme Compounds

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    Synchrotron far-IR spectroscopy and density-functional calculations are used to characterize the low-frequency dynamics of model heme FeCO compounds. The “doming” vibrational mode in which the iron atom moves out of the porphyrin plane while the periphery of this ring moves in the opposite direction determines the reactivity of oxygen with this type of molecule in biological systems. Calculations of frequencies and absorption intensities and the measured pressure dependence of vibrational modes in the model compounds are used to identify the doming and related normal modes

    The evolution of RNAs with multiple functions

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    Increasing numbers of transcripts have been reported to transmit both protein-coding and regulatory information. Apart from challenging our conception of the gene, this observation raises the question as to what extent this phenomenon occurs across the genome and how and why such dual encoding of function has evolved in the eukaryotic genome. To address this question, we consider the evolutionary path of genes in the earliest forms of life on Earth, where it is generally regarded that proteins evolved from a cellular machinery based entirely within RNA. This led to the domination of protein-coding genes in the genomes of microorganisms, although it is likely that RNA never lost its other capacities and functionalities, as evidenced by cis-acting riboswitches and UTRs. On the basis that the subsequent evolution of a more sophisticated regulatory architecture to provide higher levels of epigenetic control and accurate spatiotemporal expression in developmentally complex organisms is a complicated task, we hypothesize: (i) that mRNAs have been and remain subject to secondary selection to provide trans-acting regulatory capability in parallel with protein-coding functions; (ii) that some and perhaps many protein-coding loci, possibly as a consequence of gene duplication, have lost protein-coding functions en route to acquiring more sophisticated trans-regulatory functions; (iii) that many transcripts have become subject to secondary processing to release different products; and (iv) that novel proteins have emerged within loci that previously evolved functionality as regulatory RNAs. In support of the idea that there is a dynamic flux between different types of informational RNAs in both evolutionary and real time, we review recent observations that have arisen from transcriptomic surveys of complex eukaryotes and reconsider how these observations impact on the notion that apparently discrete loci may express transcripts with more than one function. In conclusion, we posit that many eukaryotic loci have evolved the capacity to transact a multitude of overlapping and potentially independent functions as both regulatory and protein-coding RNAs
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