Trace element analysis provides insight into the diets of early Late Miocene ungulates from the Rudabánya II locality (Hungary)

The early Late Miocene vertebrate locality of Rudabánya II (R. II) in northeastern Hungary preserves an abundance of forest-adapted ungulate species. To better understand the ecological relationships within this ancient ecosystem, we used analysis of enamel strontium/calcium (Sr/Ca) ratios to infer dietary preferences. The goals of the analysis were to: i) determine whether these ungulate species specialized in specific plants or plant parts; ii) discern whether the Sr/Ca ratios support what was previously suggested about the ecology of these species; and iii) evaluate the factors that may have acted to promote coexistence within this diverse community of predominantly browsing herbivores. Results show significant differences in the diets of the sampled species. The highest Sr/Ca ratios were displayed by the suids Parachleuastochoerus kretzoii [B1] and Propotamochoerus palaeochoerus implying a preference for Sr-rich underground plant parts. Elevated Sr/Ca ratios yielded by the cervid Lucentia aff. pierensis and equid Hippotherium intrans are indicative of intermediate feeding. The bovid Miotragocerus sp. showed higher Sr/Ca ratios than the gomphothere Tetralophodon longirostris, which is incongruent with morphological and stable isotope data, and suggested browsing by both taxa. This finding is likely the result of a difference in digestive physiology (ruminant vs. monogastric) rather than a difference in dietary behaviour. The lowest Sr/Ca ratios were displayed by the traguild Dorcatherium naui and moschid Micromeryx flourensianussuggesting a preference for Sr-poor fruits. Resource specialization and partitioning within the local environment likely acted to decrease interspecific competition and promote coexistence within the diverse ungulate community at R. II

Multiplicity Distributions in Canonical and Microcanonical Statistical Ensembles

The aim of this paper is to introduce a new technique for calculation of observables, in particular multiplicity distributions, in various statistical ensembles at finite volume. The method is based on Fourier analysis of the grand canonical partition function. Taylor expansion of the generating function is used to separate contributions to the partition function in their power in volume. We employ Laplace's asymptotic expansion to show that any equilibrium distribution of multiplicity, charge, energy, etc. tends to a multivariate normal distribution in the thermodynamic limit. Gram-Charlier expansion allows additionally for calculation of finite volume corrections. Analytical formulas are presented for inclusion of resonance decay and finite acceptance effects directly into the system partition function. This paper consolidates and extends previously published results of current investigation into properties of statistical ensembles.Comment: 53 pages, 7 figure

Particle Number Fluctuations in Relativistic Bose and Fermi Gases

Particle number fluctuations are studied in relativistic Bose and Fermi gases. The calculations are done within both the grand canonical and canonical ensemble. The fluctuations in the canonical ensemble are found to be different from those in the grand canonical one. Effects of quantum statistics increase in the grand canonical ensemble for large chemical potential. This is, however, not the case in the canonical ensemble. In the limit of large charge density a strongest difference between the grand canonical and canonical ensemble results is observed.Comment: 13 pages, 6 figure

Particle Number Fluctuations in the Microcanonical Ensemble

Particle number fluctuations are studied in the microcanonical ensemble. For the Boltzmann statistics we deduce exact analytical formulae for the microcanonical partition functions in the case of non-interacting massless neutral particles and charged particles with zero net charge. The particle number fluctuations are calculated and we find that in the microcanonical ensemble they are suppressed in comparison to the fluctuations in the canonical and grand canonical ensembles. This remains valid in the thermodynamic limit too, so that the well-known equivalence of all statistical ensembles refers to average quantities, but does not apply to fluctuations. In the thermodynamic limit we are able to calculate the particle number fluctuations in the system of massive bosons and fermions when the exact conservation laws of both the energy and charge are taken into account.Comment: REVTeX, 17 pages, 9 figures, v3: misprints a correcte

Parallel evolution of chimeric fusion genes

To understand how novel functions arise, we must identify common patterns and mechanisms shaping the evolution of new genes. Here, we take advantage of data from three Drosophila genes, jingwei, Adh-Finnegan, and Adh-Twain, to find evolutionary patterns and mechanisms governing the evolution of new genes. All three of these genes are independently derived from Adh, which enabled us to use the extensive literature on Adh in Drosophila to guide our analyses. We discovered a fundamental similarity in the temporal, spatial, and types of amino acid changes that occurred. All three genes underwent rapid adaptive amino acid evolution shortly after they were formed, followed by later quiescence and functional constraint. These genes also show striking parallels in which amino acids change in the Adh region. We showed that these early changes tend to occur at amino acid residues that seldom, if ever, evolve in Drosophila Adh. Changes at these slowly evolving sites are usually associated with loss of function or hypomorphic mutations in Drosophila melanogaster. Our data indicate that shifting away from ancestral functions may be a critical step early in the evolution of chimeric fusion genes. We suggest that the patterns we observed are both general and predictive

Staphylococcus aureus virulence factors identified by using a high-throughput Caenorhabditis elegans-killing model

Staphylococcus aureus is an important human pathogen that is also able to kill the model nematode Caenorhabditis elegans. We constructed a 2,950-member Tn917 transposon insertion library in S. aureus strain NCTC 8325. Twenty-one of these insertions exhibited attenuated C. elegans killing, and of these, 12 contained insertions in different genes or chromosomal locations. Ten of these 12 insertions showed attenuated killing phenotypes when transduced into two different S. aureus strains, and 5 of the 10 mutants correspond to genes that have not been previously identified in signature-tagged mutagenesis studies. These latter five mutants were tested in a murine renal abscess model, and one mutant harboring an insertion in nagD exhibited attenuated virulence. Interestingly, Tn917 was shown to have a very strong bias for insertions near the terminus of DNA replication

Multiplicity fluctuations in relativistic nuclear collisions

Multiplicity distributions of hadrons produced in central nucleus-nucleus collisions are studied within the hadron-resonance gas model in the large volume limit. In the canonical ensemble conservation of three charges (baryon number, electric charge, and strangeness) is enforced. In addition, in the micro-canonical ensemble energy conservation is included. An analytical method is used to account for resonance decays. Multiplicity distributions and scaled variances for negatively charged hadrons are presented along the chemical freeze-out line of central Pb+Pb (Au+Au) collisions from SIS to LHC energies. Predictions obtained within different statistical ensembles are compared with preliminary NA49 experimental results on central Pb+Pb collisions in the SPS energy range. The measured fluctuations are significantly narrower than a Poisson reference distribution, and clearly favor expectations for the micro-canonical ensemble.Comment: 6 pages, 3 figure

Multiplicity fluctuations in relativistic nuclear collisions: statistical model versus experimental data

The multiplicity distributions of hadrons produced in central nucleus-nucleus collisions are studied within the hadron-resonance gas model in the large volume limit. The microscopic correlator method is used to enforce conservation of three charges - baryon number, electric charge, and strangeness - in the canonical ensemble. In addition, in the micro-canonical ensemble energy conservation is included. An analytical method is used to account for resonance decays. The multiplicity distributions and the scaled variances for negatively, positively, and all charged hadrons are calculated along the chemical freeze-out line of central Pb+Pb (Au+Au) collisions from SIS to LHC energies. Predictions obtained within different statistical ensembles are compared with the preliminary NA49 experimental results on central Pb+Pb collisions in the SPS energy range. The measured fluctuations are significantly narrower than the Poisson ones and clearly favor expectations for the micro-canonical ensemble. Thus this is a first observation of the recently predicted suppression of the multiplicity fluctuations in relativistic gases in the thermodynamical limit due to conservation laws.Comment: 27 pages, 9 figures, corrected reference

Multiplicity Fluctuations in Hadron-Resonance Gas

The charged hadron multiplicity fluctuations are considered in the canonical ensemble. The microscopic correlator method is extended to include three conserved charges: baryon number, electric charge and strangeness. The analytical formulae are presented that allow to include resonance decay contributions to correlations and fluctuations. We make the predictions for the scaled variances of negative, positive and all charged hadrons in the most central Pb+Pb (Au+Au) collisions for different collision energies from SIS and AGS to SPS and RHIC.Comment: 19 pages, 4 figure