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    Identification of large masses of citrus fruit and rice fields in eastern Spain

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    The SuperWorlds of SU(5) and SU(5)xU(1): A Critical Assessment and Overview

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    We present an overview of the simplest supergravity models which enforce radiative breaking of the electroweak symmetry, namely the minimal SU(5)SU(5) supergravity model and the class of string-inspired/derived supergravity models based on the flipped SU(5)×U(1)SU(5)\times U(1) structure supplemented by a minimal set of additional matter representations such that unification occurs at the string scale (\sim10^{18}\GeV). These models can be fully parametrized in terms of the top-quark mass, the ratio tanβ=v2/v1\tan\beta=v_2/v_1, and three supersymmetry breaking parameters (m1/2,m0,Am_{1/2},m_0,A). The latter are chosen in the minimal SU(5)SU(5) model such that the stringent constraints from proton decay and cosmology are satisfied. In the flipped SU(5)SU(5) case we consider two string-inspired supersymmetry breaking scenaria: SU(N,1)SU(N,1) no-scale supergravity and a dilaton-induced supersymmetry breaking scenario. Both imply universal soft supersymmetry breaking parameters: m0=A=0m_0=A=0 and m_0=\coeff{1}{\sqrt{3}}m_{1/2}, A=-m_{1/2} respectively. We present a comparative study of the sparticle and Higgs spectra of both flipped SU(5)SU(5) models and the minimal SU(5)SU(5) model and conclude that all can be partially probed at the Tevatron and LEPII (and the flipped models at HERA too). In both flipped SU(5)SU(5) cases there is a more constrained version which allows to determine tanβ\tan\beta in terms of mt,mg~m_t,m_{\tilde g} and which leads to much sharper and readily accessible experimental predictions. We also discuss the prospects for indirect experimental detection: a non-trivial fraction of the parameter space of the flipped SU(5)SU(5) models is in conflict with the present experimental allowed range for the bsγb\to s\gamma rare decay mode, and the one-loop electroweak radiative corrections imply the 90\% CL upper boundComment: CERN-TH.6934/93, CTP-TAMU-34/93, LaTeX, 58 pages, 20 embedded figures. Complete ps file (~12000 blocks, 5.24MB) available via anonymous ftp from site tamsun.tamu.edu in directory incoming, filename: CTP-TAMU-34-93.p

    Understanding the Mass-Radius Relation for Sub-Neptunes: Radius as a Proxy for Composition

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    Transiting planet surveys like Kepler have provided a wealth of information on the distribution of planetary radii, particularly for the new populations of super-Earth and sub-Neptune sized planets. In order to aid in the physical interpretation of these radii, we compute model radii for low-mass rocky planets with hydrogen-helium envelopes. We provide model radii for planets 1-20 Earth masses, with envelope fractions from 0.01-20%, levels of irradiation 0.1-1000x Earth's, and ages from 100 Myr to 10 Gyr. In addition we provide simple analytic fits that summarize how radius depends on each of these parameters. Most importantly, we show that at fixed composition, radii show little dependence on mass for planets with more than ~1% of their mass in their envelope. Consequently, planetary radius is to first order a proxy for planetary composition for Neptune and sub-Neptune sized planets. We recast the observed mass-radius relationship as a mass-composition relationship and discuss it in light of traditional core accretion theory. We discuss the transition from rocky super-Earths to sub-Neptune planets with large volatile envelopes. We suggest 1.75 Earth radii as a physically motivated dividing line between these two populations of planets. Finally, we discuss these results in light of the observed radius occurrence distribution found by Kepler.Comment: 17 pages, 9 figures, 7 tables, submitted to Ap

    A study of stopping power in nuclear reactions at intermediate energies

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    We show a systematic experimental study based on INDRA data of the stopping power in central symmetric nuclear reactions. Total mass of the systems goes from 80 to 400 nucleons while the incident energy range is from 12 AMeV to 100 AMeV. The role of isospin diffusion at 32 and 45 MeV/nucleon with 124,136Xe projectiles on 112,124Sn targets performed at GANIL is also discussed. Results suggest a strong memory of the entrance channel above 20 AMeV/A (nuclear transparency) and, as such, constitute valuable tests of the microscopic transport models.Comment: 7 pages, 3 figures, Proceedings of International Workshop on Multifragmentation and Related Topics (IWM 2009), Catania, Italy, 4 Nov-7 Nov 200
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