219 research outputs found

    1881 and 1949 earthquakes at the Chios-Cesme Strait (Aegean Sea) and their relation to tsunamis

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    The most earthquake-prone areas in the eastern central Aegean Sea are the Izmir Bay, the Karaburun peninsula and the island of Chios. The level of seismic activity and tsunami potential are influenced by the presence of normal faults around the region. There have been about 20 moderate-size earthquakes from 496 BC to 1949 AD. Among these earthquakes, the ones on the dates 20 March 1389, 13 November 1856, 19/22 January 1866, 3 April 1881 and 23 July 1949 produced tsunamis. The Chios-Cesme earthquake (1881, Mw 6.5) took place in the South of the Cesme strait while the Chios-Karaburun earthquake (1949, Mw 6.7) occurred in the North. The tsunamis caused by the earthquakes affected the coasts of Chios Island and Cesme. These waves are thought to be associated with the earthquakes and co-seismic underwater failures possibly occurred along the coasts of the Chios Island and Karaburun Peninsula or on the complex subaqueous morphology between these lands. Some sea waves or oscillations observed following the aftershocks are believed to be related to other natural phenomena; e.g. the seiches occurred mainly in open-narrow bays as triggered by the earthquakes

    Genetic characterization of grape (Vitis vinifera L.) germplasm from Southeast Anatolia by SSR markers

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    Southeast Anatolia is located in close proximity to the center of origin of grapes and is an important grape producing area of Turkey. The important location of this region for grape genetic diversity together with its diverse ecological conditions may have led to the development of grape germplasm that is unique to this region. However, so far little has been done to genetically analyze this grape germplasm. In this study, we genetically analyzed 55 grape cultivars originating from six different provinces of this region using 14 simple sequence repeat (SSR) loci and a number of ampeolographic characteristics. Based on these analyses, one case of synonymous and four cases of homonymous grape cultivars were identified. The contribution of our results to better characterization of the grape germplasm of the region as well as future germplasm management and breeding efforts is discussed.

    Simple sequence repeat-based assessment of genetic diversity in 'Dimrit' and 'Gemre' grapevine accessions from Turkey

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    It is widely believed that Turkey has played an important role in the evolution of modern day grapes due to its unique geographical location with close proximity to the regions of grape diversity. Despite this, the rich grape germplasm found in Turkey has not been sufficiently analyzed genetically. In this study, 31 grapevine accessions from 'Dimrit' (or 'Dilmit') and 'Gemre' grape groups were genetically analyzed at eight SSR (microsatellite) loci (VVS2, VVMD5, VVMD7, VVMD24, VVMD27, VVMD28, VrZAG62 and VrZAG79) and for a number of ampeolographic characteristics. These analyses identified sufficient genetic diversity between these two grape groups that, in general, clustered separately in the dendrogram constructed based on the SSR data. However, the ecogeographical distribution and genetic relationship of the genotypes did not show any significant correlation. Two 'Gemre' accessions were determined as genetically identical. In addition, one case of synonym and several cases of homonym genotypes were identified. The results reported here are important first steps towards better characterization of these grape genotypes and would aid future germplasm management and breeding efforts.

    Time-Dependent Vacuum Energy Induced by D-Particle Recoil

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    We consider cosmology in the framework of a `material reference system' of D particles, including the effects of quantum recoil induced by closed-string probe particles. We find a time-dependent contribution to the cosmological vacuum energy, which relaxes to zero as 1/t2\sim 1/ t^2 for large times tt. If this energy density is dominant, the Universe expands with a scale factor R(t)t2R(t) \sim t^2. We show that this possibility is compatible with recent observational constraints from high-redshift supernovae, and may also respect other phenomenological bounds on time variation in the vacuum energy imposed by early cosmology.Comment: 14 pages LATEX, no figure

    Compactifications with S-Duality Twists

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    We consider generalised Scherk Schwarz reductions of supergravity and superstring theories with twists by electromagnetic dualities that are symmetries of the equations of motion but not of the action, such as the S-duality of D=4, N=4 super-Yang-Mills coupled to supergravity. The reduction cannot be done on the action itself, but must be done either on the field equations or on a duality invariant form of the action, such as one in the doubled formalism in which potentials are introduced for both electric and magnetic fields. The resulting theory in odd-dimensions has massive form fields satisfying a self-duality condition dAmAdA \sim m*A. We construct such theories in D=3,5,7.Comment: Latex, 26 pages. References adde

    Two-loop Radiative Neutrino Mechanism in an SU(3)L×U(1)NSU(3)_L\times U(1)_N Gauge Model

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    By using the LeL_e - LμL_\mu - LτL_\tau symmetry, we construct an SU(3)L×U(1)NSU(3)_L\times U(1)_N gauge model that provides two-loop radiative neutrino masses as well as one-loop radiative neutrino masses. The generic smallness of two-loop neutrino masses leading to Δm2\Delta m^2_\odot compared with one-loop neutrino masses leading to Δmatm2\Delta m^2_{atm} successfully explains Δmatm2\Delta m^2_{atm} >>>> Δm2\Delta m^2_{\odot} by invoking the LeL_e - LμL_\mu - LτL_\tau breaking. The Higgs scalar (h+h^+) that initiates radiative mechanisms is unified into a Higgs triplet together with the standard Higgs scalar (ϕ+\phi^+, ϕ0\phi^0) to form (ϕ+\phi^+, ϕ0\phi^0, h+h^+), which calls for three families of lepton triplets: (νLi\nu^i_L, Li\ell^i_L, ωLi\omega^i_L) (i = 1,2,3), where ωi\omega^i denote heavy neutral leptons. The two-loop radiative mechanism is found possible by introducing a singly charged scalar, which couples to RiωRj\ell^i_R\omega^j_R (i,j = 2,3).Comment: with 10 pages, revtex, including 2 figures, accepted for publication in Phys. Rev. D (with undefined latex citation indices removed

    Supersymmetry and the relationship between a class of singular potentials in arbitrary dimensions

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    The eigenvalues of the potentials V1(r)=A1r+A2r2+A3r3+A4r4V_{1}(r)=\frac{A_{1}}{r}+\frac{A_{2}}{r^{2}}+\frac{A_{3}}{r^{3}}+\frac{A_{4 }}{r^{4}} and V2(r)=B1r2+B2r2+B3r4+B4r6V_{2}(r)=B_{1}r^{2}+\frac{B_{2}}{r^{2}}+\frac{B_{3}}{r^{4}}+\frac{B_{4}}{r^ {6}}, and of the special cases of these potentials such as the Kratzer and Goldman-Krivchenkov potentials, are obtained in N-dimensional space. The explicit dependence of these potentials in higher-dimensional space is discussed, which have not been previously covered.Comment: 13 pages article in LaTEX (uses standard article.sty). Please check "http://www1.gantep.edu.tr/~ozer" for other studies of Nuclear Physics Group at University of Gaziante

    Majoron emitting neutrinoless double beta decay in the electroweak chiral gauge extensions

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    Fundamental mechanisms for Majoron emitting neutrinoless double beta decay in SU(3)_C x G_W x U(1) models, for electroweak flavor chiral extensions, G_W = SU(3)_L and SU(4)_L are pointed out. Both kinds of known Majoron emitting processes, charged Majoron emitting where the massless Nambu-Goldstone boson itself carries lepton charge, L=2L=-2, and the ordinary Majoron emitting where the boson has a small mass are found possible. PACS numbers: 11.15.Ex, 12.60.Fr, 14.80.CpComment: 18 pages, Revtex, 3 Postscript figures. To be published in Phys.Rev.D(1 May 1998

    Evolution of the Scale Factor with a Variable Cosmological Term

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    Evolution of the scale factor a(t) in Friedmann models (those with zero pressure and a constant cosmological term Lambda) is well understood, and elegantly summarized in the review of Felten and Isaacman [Rev. Mod. Phys. 58, 689 (1986)]. Developments in particle physics and inflationary theory, however, increasingly indicate that Lambda ought to be treated as a dynamical quantity. We revisit the evolution of the scale factor with a variable Lambda-term, and also generalize the treatment to include nonzero pressure. New solutions are obtained and evaluated using a variety of observational criteria. Existing arguments for the inevitability of a big bang (ie., an initial state with a=0) are substantially weakened, and can be evaded in some cases with Lambda_0 (the present value of Lambda) well below current experimental limits.Comment: 29 pages, 12 figures (not included), LaTeX, uses Phys Rev D style files (revtex.cls, revtex.sty, aps.sty, aps10.sty, prabib.sty). To appear in Phys Rev

    Perturbation evolution in cosmologies with a decaying cosmological constant

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    Structure formation models with a cosmological constant are successful in explaining large-scale structure data, but are threatened by the magnitude-redshift relation for Type Ia supernovae. This has led to discussion of models where the cosmological `constant' decays with time, which might anyway be better motivated in a particle physics context. The simplest such models are based on scalar fields, and general covariance demands that a time-evolving scalar field also supports spatial perturbations. We consider the effect of such perturbations on the growth of adiabatic energy density perturbations in a cold dark matter component. We study two types of model, one based on an exponential potential for the scalar field and the other on a pseudo-Nambu Goldstone boson. For each potential, we study two different scenarios, one where the scalar field presently behaves as a decaying cosmological constant and one where it behaves as dust. The initial scalar field perturbations are fixed by the adiabatic condition, as expected from the inflationary cosmology, though in fact we show that the choice of initial condition is of little importance. Calculations are carried out in both the zero-shear (conformal newtonian) and uniform-curvature gauges. We find that both potentials allow models which can provide a successful alternative to cosmological constant models.Comment: 14 pages RevTeX file with three figures incorporated (uses RevTeX and epsf). Also available by e-mailing ARL, or by WWW at http://star-www.maps.susx.ac.uk/papers/lsstru_papers.html Revised version corrects an error in Eq10; results unchange
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