Present status of the geochronology of the early Precambrian of South India

The present status of Precambrian geochronology of South India was summarized. Support was offered for Raith's conclusion of an extensive 3.3 to 3.4-Ga tonalite-forming event. Evidence that the Sargur supracrustal sequence predates this event, however, remains equivocal. The only reliably dated supracrustal rocks are the similar to 3.0-Ga Chitradurga acid volcanics, and these are separated from the older Bababudan supracrustals by a major gneiss-forming event. A major unsolved problem relates to the timing of the Sargur supracrustals in relation to the basal units of the Dharwar succession. An appeal was made for more geochronological work on South Indian samples

Learning to detect an oddball target with observations from an exponential family

The problem of detecting an odd arm from a set of K arms of a multi-armed bandit, with fixed confidence, is studied in a sequential decision-making scenario. Each arm's signal follows a distribution from a vector exponential family. All arms have the same parameters except the odd arm. The actual parameters of the odd and non-odd arms are unknown to the decision maker. Further, the decision maker incurs a cost for switching from one arm to another. This is a sequential decision making problem where the decision maker gets only a limited view of the true state of nature at each stage, but can control his view by choosing the arm to observe at each stage. Of interest are policies that satisfy a given constraint on the probability of false detection. An information-theoretic lower bound on the total cost (expected time for a reliable decision plus total switching cost) is first identified, and a variation on a sequential policy based on the generalised likelihood ratio statistic is then studied. Thanks to the vector exponential family assumption, the signal processing in this policy at each stage turns out to be very simple, in that the associated conjugate prior enables easy updates of the posterior distribution of the model parameters. The policy, with a suitable threshold, is shown to satisfy the given constraint on the probability of false detection. Further, the proposed policy is asymptotically optimal in terms of the total cost among all policies that satisfy the constraint on the probability of false detection

Bayesian Gait Optimization for Bipedal Locomotion

One of the key challenges in robotic bipedal locomotion is finding gait parameters that optimize a desired performance criterion, such as speed, robustness or energy efficiency. Typically, gait optimization requires extensive robot experiments and specific expert knowledge. We propose to apply data-driven machine learning to automate and speed up the process of gait optimization. In particular, we use Bayesian optimization to efficiently find gait parameters that optimize the desired performance metric. As a proof of concept we demonstrate that Bayesian optimization is near-optimal in a classical stochastic optimal control framework. Moreover, we validate our approach to Bayesian gait optimization on a low-cost and fragile real bipedal walker and show that good walking gaits can be efficiently found by Bayesian optimization. © 2014 Springer International Publishing

ETHNOMEDICINAL STUDIES IN SELECTED MEDICINAL PLANTS OF DHONI FOREST, WESTERN GHATS, KERALA.

Objective: The objective of the study was to identify and utilize medicinal plants used by Irula tribal's of Dhoni Forest, Kerala.Methods: Frequent field visits were made throughout the study period from October 2011 to June 2012 in the study area.Results: A total of 32 medicinal plant species used by the Irula tribes were documented. These medicinal plant species were distributed in 23 families and 32 genera. In terms of number of medicinal plant species, Apocynaceae, Malvaceae and Menispermaceae were the most dominant families of medicinal plants. The results of the present study provide evidences that medicinal plants continue to play an important role in the health care system of the tribal community.Conclusion: The treasure of knowledge on traditional medicine is gradually vanishing due to modernization and civilization of tribal community and also the younger generation not showing any interest in learning those practices. The collected detailed information on the list of plants and their therapeutic practices among Irula tribes may be helpful to improve the future pharmaceutical applications. Key words: Dhoni Forest, Irula tribe, medicinal plants, Ethnomedicinal uses

Synthesis and Characterisation of Nanomaterials

Development of synthesis protocols for realising nanomaterials over a range of sizes, shapes,and chemical compositions is an important aspect of nanotechnology. The remarkable size-dependent physico-chemical properties of nanoparticles have fascinated and inspired researchactivity in this direction. This paper describes some aspects on synthesis and characterisationof nanoparticles of metals, metal alloys, and oxides, either in the form of thin films or bulk shapes.A brief discussion on processing of two-phase nanocomposite magnets is also presented.Defence Science Journal, 2008, 58(4), pp.504-516, DOI:http://dx.doi.org/10.14429/dsj.58.167

Market liquidity, investor participation and managerial autonomy: why do firms go private?

We analyze a publicly-traded firm's decision to stay public or go private when managerial autonomy from shareholder intervention affects the supply of productive inputs by management. We show that both the advantage and the disadvantage of public ownership relative to private ownership lie in the liquidity of public ownership. While the liquidity of public ownership lets shareholders trade easily and supply capital at a lower cost, the liquidity-engendered trading also results in stochastic shocks to a firm's shareholder base. This exposes management to uncertainty regarding the identity of future shareholders and their extent of intervention in management decisions and in turn curtails managerial incentives. By contrast, because of its illiquidity, private ownership provides a stable shareholder base and improves these inputprovision incentives but results in a higher cost of capital. Thus, capital market liquidity, while being a principal advantage of public ownership, also has a surprising 'dark side' that discourages public ownership. Our model takes seriously a key difference between private and public equity markets in that, unlike the private market, the firm's shareholder base, namely the extent of investor participation, is stochastic in the public market. This allows us to extract predictions about the effects of investor participation on the stock price level and volatility and on the public firm's incentives to go private, thereby providing a link between investor participation and firm participation in public markets. Lesser investor participation induces lower and more volatile stock prices, encouraging public firms to go private, whereas greater investor participation encourages younger firms to go public. Moreover, IPO underpricing is optimal because it is shown to lead to a higher and less volatile post-IPO stock price, greater autonomy for the manager and a higher supply of privately-costly managerial inputs

High rate of extrapair paternity in a human population demonstrates diversity in human reproductive strategies.

Among nonhuman species, social monogamy is rarely accompanied by complete fidelity. Evolutionary theory predicts that the rate of extrapair paternity (EPP) should vary according to socioecological conditions. In humans, however, geneticists contend that EPP is negligible and relatively invariable. This conclusion is based on a limited set of studies, almost all of which describe European-descent groups. Using a novel, double-blind method designed in collaboration with a community of Himba pastoralists, we find that the rate of EPP in this population is 48%, with 70% of couples having at least one EPP child. Both men and women were very accurate at detecting cases of EPP. These data suggest that the range of variation in EPP across human populations is substantially greater than previously thought. We further show that a high rate of EPP can be accompanied by high paternity confidence, which highlights the importance of disaggregating EPP from the notion of "cuckoldry.