1,048 research outputs found

    Studies of extra-solar OORT clouds and the Kuiper disk

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    This is the second report for NAGW-3023, Studies of Extra-Solar Oort Clouds and the Kuiper Disk. We are conducting research designed to enhance our understanding of the evolution and detectability of comet clouds and disks. This area holds promise for also improving our understanding of outer solar system formation, the bombardment history of the planets, the transport of volatiles and organics from the outer solar system to the inner planets, and the ultimate fate of comet clouds around the Sun and other stars. According to 'standard' theory, both the Kuiper Disk and Oort Cloud are (at least in part) natural products of the planetary accumulation stage of solar system formation. One expects such assemblages to be a common attribute of other solar systems. Therefore, searches for comet disks and clouds orbiting other stars offer a new method for infering the presence of planetary systems. Our three-year effort consists of two major efforts: (1) observational work to predict and search for the signatures of Oort Clouds and comet disks around other stars; and (2) modelling studies of the formation and evolution of the Kuiper Disk (KD) and similar assemblages that may reside around other stars, including Beta Pic. These efforts are referred to as Task 1 and 2, respectively

    Studies of extra-solar Oort Clouds and the Kuiper disk

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    In 1991 we detected extended 1.1 mm emission around Fomalhaut (alpha PsA) at distances in order of magnitude beyond previous detections. This emission is plausibly related to the presence of an extended comet cloud, like our Oort Cloud, and may therefore represent indirect evidence for the formation of a planetary system at Fomalhaut. We propose now to extend this work to create a map of the angular and spatial extent of this emission. Fomalhaut is the only known main-sequence, submm-resolved IR excess source besides beta Pic

    Collisional evolution in the Vulcanoid region: Implications for present-day population constraints

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    We explore the effects of collisional evolution on putative Vulcanoid ensembles in the region between 0.06 and 0.21 AU from the Sun, in order to constrain the probable population density and population structure of this region today. Dynamical studies have shown that the Vulcanoid Zone (VZ) could be populated. However, we find that the frequency and energetics of collisional evolution this close to the Sun, coupled with the efficient radiation transport of small debris out of this region, together conspire to create an active and highly intensive collisional environment which depletes any very significant population of rocky bodies placed in it, unless the bodies exhibit orbits that are circular to ~10^-3 or less, or highly lossy mechanical properties that correspond to a fraction of impact energy significantly less than 10% being imparted to ejecta. The most favorable locale for residual bodies to survive in this region is in highly circular orbits near the outer edge of the dynamically stable Vulcanoid Zone (i.e., near 0.2 AU), where collisional evolution and radiation transport of small bodies and debris proceed most slowly. If the mean random orbital eccentricity in this region exceeds ~10^-3, then our work suggests it is unlikely that more than a few hundred objects with radii larger than 1 km will be found in the entire VZ; assuming the largest objects have a radius of 30 km, then the total mass of bodies in the VZ down to 0.1 km radii is likely to be no more than ~10^-6Mearth, <10^-3 the mass of the asteroid belt. Despite the dynamical stability of large objects in this region (Evans & Tabachnik 1999), it is plausible that the entire region is virtually empty of km-scale and larger objects.Comment: text plus 7 .ps figures, gzipped. Icarus, 2000, in pres

    Designing a Pro-Active Stance for India in the Doha Development Agenda Negotiations

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    In this paper, we first summarize the framework that has been agreed upon as the basis for the WTO Doha Development Agenda (DDA) negotiations. We then discuss briefly the design and mission of the WTO and the economic effects of multilateral trade liberalization. Thereafter, we discuss the conditions for India’s realization of the maximum benefits from the DDA negotiations and the implications for broader Indian domestic policy reforms. We then set out our recommendations for India’s pro-active involvement and negotiating strategies in the DDA negotiations for multilateral trade liberalization in agricultural products, manufactures, and services, and for improvements in WTO rules governing trade and related issues. We conclude with a brief discussion of the policy agenda adopted by India’s newly elected coalition parties, the implications of the emphasis on social reform and equity for India’s negotiating strategies in the DDA negotiations, and a vision of the role that India might play in the global trading system and in world politics.

    Enhancing the Benefits for Developing Countries in the Doha Development Agenda Negotiations

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    This is a position paper dealing with the major issues of the Doha Round negotiations that are of importance for developing countries. It was prepared for circulation prior to the Cancun Ministerial Meeting of the WTO. It provides recommendations for WTO decision making, agricultural policies, market access, intellectual property, services, the Singapore issues, technical assistance, and special treatment. These are accompanied by brief arguments in support of these recommendations.

    Globalization’s Bystanders: Does Trade Liberalization Hurt Countries that Do Not Participate?

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    This paper uses trade theory to examine the effects of trade liberalization on countries that do not participate in it. These include both countries that fail to participate in multilateral trade negotiations, and also countries that lie outside of preferential trading arrangements such as free trade areas. The analysis suggests that, while it is theoretically possible for excluded countries to gain, through improved terms of trade, from trade liberalization, several reasons suggest that they are more likely to lose.Trade liberalization, Globalization

    A CCD search for distant satellites of asteroids 3 Juno and 146 Lucina

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    The results of CCD searches for satellites of asteroids 146 Lucina and 3 Juno are reported. Juno is one of the largest asteroids (D = 244 km); no previous deep imaging search for satellites around it has been reported. A potential occultation detection of a small satellite orbiting 146 Lucina (D = 137 km) km was reported by Arlot et al. (1985), but has not been confirmed. Using the 2.1 m reflector at McDonald Observatory in 1990 and 1991 with a CCD camera equipped with a 2.7 arc-sec radius occulting disk, limiting magnitudes of m(sub R) = 19.5 and m(sub R) = 21.4 were achieved around these two asteroids. This corresponds to objects of 1.6 km radius at Juno's albedo and distance, and 0.6 km radius at Lucina's albedo and distance. No satellite detections were made. Unless satellites were located behind our occultation mask, these two asteroids do not have satellites larger than the radii given above

    Enhancing the Benefits for India and Other Developing Countries in the Doha Development Agenda Negotiations

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    The Doha Round of multilateral trade negotiations in the World Trade Organization (WTO) has been billed from the start as the “Doha Development Agenda,” with the promise in the Doha Ministerial Declaration to “place [developing countries’] needs and interests at the heart of the Work Programme adopted in this Declaration.” The reason for this emphasis was in part the perception that previous rounds had neglected the interests of developing countries or, in the case of the Uruguay Round, had brought developing countries on board with promises that were misleading or not likely to be kept. The collapse of the September 2003 Cancun Ministerial Meeting reinforced the need to address the interests of developing countries, and recent agreements reached at the WTO in Geneva suggest that the Doha negotiations may now be on track. What is now important to emphasize, as the negotiations get under way, is to follow through with actions that are designed to fulfill the special needs of developing countries and to address their problems in implementing these actions. In our paper we lay out what we believe to be the most important actions that could be taken in the Doha Round for the benefit of developing countries, including India. We base these suggestions primarily on the understanding of the economics of international trade that has been developed over the last two centuries and is widely taught in the universities of the world, and also on the research in recent years dealing with specific aspects of trade negotiations in general and of the Doha Round in particular. With regard to the interests of developing countries generally, we provide recommendations for WTO decision-making, agricultural policies, market access, intellectual property, services, the Singapore issues, technical assistance, and special treatment. Each of these recommendations is accompanied by brief arguments in support. The paper then goes on to review several more specific policy and negotiating recommendations focused on India. It is essential that India and other developing countries participate actively and constructively in the Doha negotiations to further their own interests. They cannot rely on the best-intentioned developed countries to do this for them, since the developed countries will inevitably find themselves making compromises in favor of their own interests and in response to powerful pressures from their domestic constituents. Many developing countries are at a disadvantage in the negotiating process, due to their resource limitations, and in many cases due also to their inexperience in negotiations. Offsetting these disadvantages, however, are their large numbers and the compelling case that can be made for meeting their needs. What the developing countries need is leadership and cooperation, which India is well suited to provide. What is also needed is a willingness to listen and be flexible on the part of their developed country counterparts.
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