The assessment of size in fossil felidae

Estimations of body size in fossil vertebrates depend on establishing the relationships between body mass, overall length or some measure of stature and measurements taken on skeletal elements in living relatives or close proxies. However, most osteological collections lack information on body size for individual specimens, and published investigations usually fa11 back on summary data derived from the literature to plot against measurements taken directly on the skeletal material. The utility of such approaches beyond very general indications of size is open to question. In an effort to reduce these problems we attempt to establish some objective basis for using skeletal elements for the purpose of size estimation in the larger Felidae of the genus Panthera, using data for the jaguar, Panthera onca. We show that cranial length offers a good indication of overall size in the living animal, and that various other cranial dimensions correlate closely with that measurement, while individual teeth, despite their frequent occurrence in assemblages, show a looser relationship and therefore appear less useful for size estimations of fossil material than has been thought.Las estimaciones de la talla corporal en vertebrados fósiles depende de las relaciones establecidas entre el peso corporal, la longitud total o alguna medida de estatura tomada de los elementos esqueléticos de animales actuales emparentados o muy afines. Sin embargo, en muchas colecciones osteológicas falta información sobre la talla corporal de los ejemplares, de forma que las investigaciones publicadas usualmente recurren a datos sintetizados de la literatura que se relacionan con medidas tomadas directamente del material esquelético. La utilidad de estas aproximaciones más allá de indicaciones generales sobre la talla es discutible. En un esfuerzo de minimizar estos problemas intentamos establecer bases objetivas para el uso de los elementos esqueléticos con el propósito de estimar la talla de los grandes Felidae del género Panthera, utilizando los datos obtenidos del jaguar, Panthera onca. Se muestra que la longitud craneal ofrece una buena indicación de la talla total en los animales actuales, y que otras dimensiones craneales se correlacionan estrechamente con esta medida, mientras que los dientes aislados, a pesar de su hallazgo frecuente en las asociaciones fósiles, muestra una menor correlación y por lo tanto es menos útil para la estimación de la talla en formas fósiles de lo que anteriormente se había pensado

Tetrahedral Symmetry in Ground- and Low-Lying States of Exotic A ~ 110 Nuclei

Recent theoretical calculations predict a possible existence of nuclei with tetrahedral symmetry: more precisely, the mean-field hamiltonians of such nuclei are symmetric with respect to double point-group Td. In this paper, we focus on the neutron-rich Zirconium isotopes as an example and present realistic mean-field calculations which predict tetrahedral ground-state configurations in 108,110Zr and low-lying excited states of tetrahedral symmetry in a number of N > 66 isotopes. The motivations for focusing on these nuclei, as well as a discussion of the possible experimental signatures of tetrahedral symmetry are also presented.Comment: Accepted in Phys. Rev. C - Rapid Communication

Microscopic Surface Structure of Liquid Alkali Metals

We report an x-ray scattering study of the microscopic structure of the surface of a liquid alkali metal. The bulk liquid structure factor of the eutectic K67Na33 alloy is characteristic of an ideal mixture, and so shares the properties of an elemental liquid alkali metal. Analysis of off-specular diffuse scattering and specular x-ray reflectivity shows that the surface roughness of the K-Na alloy follows simple capillary wave behavior with a surface structure factor indicative of surface induced layering. Comparison of thelow-angle tail of the K67Na33 surface structure factor with the one measured for liquid Ga and In previously suggests that layering is less pronounced in alkali metals. Controlled exposure of the liquid to H2 and O2 gas does not affect the surface structure, indicating that oxide and hydride are not stable at the liquid surface under these experimental conditions.Comment: 12 pages, 3 figures, published in Phys. Rev.

Searches for violation of fundamental time reversal and space reflection symmetries in solid state experiments

The electric dipole moment (EDM) of a particle violates both time reversal (T) and space reflection (P) symmetries. There have been recent suggestions for searches of the electron EDM using solid state experiments [1,2]. These experiments could improve the sensitivity compared to present atomic and molecular experiments by several orders of magnitude. In the present paper we calculate the expected effect. We also suggest that this kind of experiment is sensitive to T,P-violation in nuclear forces and calculate effects caused by the nuclear Schiff moment. The compounds under consideration contain magnetic Gd$^{3+}$ ions and oxygen O$^{2-}$ ions. We demonstrate that the main mechanism for the T,P-odd effects is related to the penetration of the Oxygen 2p-electrons to the Gd core. All the effects are related to the deformation of the crystal lattice.Comment: 13 pages, 6 figure

T-odd Correlations in the Decay of Scalar Fermions

We define a CP sensitive asymmetry in the sfermion decays \ti f \to f \ti\chi^0_j \ell \bar \ell, f \ti\chi^0_j q \bar q, based on triple product correlations between the momenta of the outgoing fermions. We study this asymmetry in the MSSM with complex parameters. We show that the asymmetry is sensitive to the phases of the parameters $\mu$ and $M_1$. The leading contribution stems from the decay chain \ti f\to f \ti\chi^0_j\to f \ti\chi^0_1 Z\to f \ti\chi^0_1 \ell \bar \ell (f \ti\chi^0_1 q \bar q), for which we obtain analytic formulae for the amplitude squared. The asymmetry can go up to 3% for \ti f\to f \ti\chi^0_1 \ell \bar \ell, and up to 20% for \ti f\to f \ti\chi^0_1 q \bar q. We also estimate the rates necessary to measure the asymmetry.Comment: 18 pages, 5 figures, 2 tables; comments and references added; two tables added; version to appear in Eur. Phys.

Energy levels and lifetimes of Gd IV and enhancement of the electron dipole moment

We have calculated energy levels and lifetimes of 4f7 and 4f6 5d configurations of Gd IV using Hartree-Fock and configuration interaction methods. This allows us to reduce significantly the uncertainty of the theoretical determination of the electron electric dipole moment (EDM) enhancement factor in this ion and, correspondingly, in gadolinium-containing garnets for which such measurements were recently proposed. Our new value for the EDM enhancement factor of Gd+3 is -2.2 +- 0.5. Calculations of energy levels and lifetimes for Eu~III are used to control the accuracy.Comment: Submitted to Phys. Rev. A 6 pages, 0 figures, 3 table