Identification of cryptic species of rodents (Mastomys, Aethomys, Saccostomus) in the Kruger National Park

Mastomys natalensis, Aethomys chrysophilus and Saccostomus campestris are three common and widespread rodent species in the Kruger National Park. Chromosomal and protein electrophoretic investigations reveal that these species are in fact complexes of morphologically similar, though genetically distinct, species. Their respective distributions in the Kruger National Park are reported and species diagnostic characters (diploid chromosome number, genitalia, spermatozoa and electromorphs) are presented for the practical identification of the cryptic species. The value of a genetical approach to resolving cryptic species is emphasized with respect to ecological studies

Effects of Anabolic Implants on Reproductive Function, Carcass Characteristics and Performance in Postweaned Beef Bulls

Angus bulls averaging 620 lb were used to study the effects of implants on performance, carcass characteristics and reproductive parameters of intact males. Sixty-six bulls were randomly assigned to four treatments. These treatments were (1) nonimplanted, (2) implanted with 36 mg of Ralgro every 60 t o 70 days, (3) implanted with 220 mg of Synovex-S every 60 t o 70 days, (4) implanted with 24 mg of Compudose every 180 days. Body weights were taken a t the initiation of the trial and every 28 days. Blood samples were collected v i a jugular venipuncture weekly for 9 weeks and then monthly for 4 months with the f i n a l sample taken a t slaughter. Blood was evaluated f o r testosterone, luteinizing hormone and growth hormone levels . Bulls were on test 217 days. Final average weight and hip height were 1142 lb and 49.6 in ., respectively. Nonimplanted bulls had the largest final scrotal circumference of 39.6 cm compared to 38.8 cm for Ralgro-, 38.6 cm for Compudose- and 37.8 cm for Synovex-implanted bulls. Implanting postweaning had little effect on average daily gain, hip height, testicular weight, testosterone, luteinizing hormone levels and sperm chromatin structure. Synovex implanted bulls had the highest growth hormone levels. Compudose- and Synovex-implanted bulls had the heaviest (PC .01) carcass weights and dressing percentage. Also, the Synovex-implanted bulls had the greatest (P\u3c.01) fat thickness at the 12th rib and least desirable yield grade. No difference was present for longissimus muscle, and KPH fat

On the properties of the transition matrix in bouncing cosmologies

We elaborate further on the evolution properties of cosmological fluctuations through a bounce. We show this evolution to be describable either by ``transmission'' and ``reflection'' coefficients or by an effective unitary S-matrix. We also show that they behave in a time reversal invariant way. Therefore, earlier results are now interpreted in a different perspective and put on a firmer basis.Comment: 4 pages, 1 figure, to appear in PR

Multiple field inflation

Inflation offers a simple model for very early evolution of our Universe and the origin of primordial perturbations on large scales. Over the last 25 years we have become familiar with the predictions of single-field models, but inflation with more than one light scalar field can alter preconceptions about the inflationary dynamics and our predictions for the primordial perturbations. I will discuss how future observational data could distinguish between inflation driven by one field, or many fields. As an example, I briefly review the curvaton as an alternative to the inflaton scenario for the origin of structure.Comment: 27 pages, no figures. To appear in proceedings of 22nd IAP Colloquium, Inflation +25, Paris, June 200

An Observational Test of Two-field Inflation

We study adiabatic and isocurvature perturbation spectra produced by a period of cosmological inflation driven by two scalar fields. We show that there exists a model-independent consistency condition for all two-field models of slow-roll inflation, despite allowing for model-dependent linear processing of curvature and isocurvature perturbations during and after inflation on super-horizon scales. The scale-dependence of all spectra are determined solely in terms of slow-roll parameters during inflation and the dimensionless cross-correlation between curvature and isocurvature perturbations. We present additional model-dependent consistency relations that may be derived in specific two-field models, such as the curvaton scenario.Comment: 6 pages, latex with revtex, no figures; v2, minor changes, to appear in Physical Review

Non-Gaussianity from Inflation

Correlated adiabatic and isocurvature perturbation modes are produced during inflation through an oscillation mechanism when extra scalar degrees of freedom other than the inflaton field are present. We show that this correlation generically leads to sizeable non-Gaussian features both in the adiabatic and isocurvature perturbations. The non-Gaussianity is first generated by large non-linearities in some scalar sector and then efficiently transferred to the inflaton sector by the oscillation process. We compute the cosmic microwave background angular bispectrum, providing a characteristic feature of such inflationary non-Gaussianity,which might be detected by upcoming satellite experiments.Comment: Revised version accepted for publication in Phys. Rev. D. 19 pages, LaTeX fil

Curvatons in Supersymmetric Models

We study the curvaton scenario in supersymmetric framework paying particular attention to the fact that scalar fields are inevitably complex in supersymmetric theories. If there are more than one scalar fields associated with the curvaton mechanism, isocurvature (entropy) fluctuations between those fields in general arise, which may significantly affect the properties of the cosmic density fluctuations. We examine several candidates for the curvaton in the supersymmetric framework, such as moduli fields, Affleck-Dine field, $F$- and $D$-flat directions, and right-handed sneutrino. We estimate how the isocurvature fluctuations generated in each case affect the cosmic microwave background angular power spectrum. With the use of the recent observational result of the WMAP, stringent constraints on the models are derived and, in particular, it is seen that large fraction of the parameter space is excluded if the Affleck-Dine field plays the role of the curvaton field. Natural and well-motivated candidates of the curvaton are also listed.Comment: 34 pages, 5 figure

Adiabatic and Isocurvature Perturbations for Multifield Generalized Einstein Models

Low energy effective field theories motivated by string theory will likely contain several scalar moduli fields which will be relevant to early Universe cosmology. Some of these fields are expected to couple with non-standard kinetic terms to gravity. In this paper, we study the splitting into adiabatic and isocurvature perturbations for a model with two scalar fields, one of which has a non-standard kinetic term in the Einstein-frame action. Such actions can arise, e.g., in the Pre-Big-Bang and Ekpyrotic scenarios. The presence of a non-standard kinetic term induces a new coupling between adiabatic and isocurvature perturbations which is non-vanishing when the potential for the matter fields is nonzero. This coupling is un-suppressed in the long wavelength limit and thus can lead to an important transfer of power from the entropy to the adiabatic mode on super-Hubble scales. We apply the formalism to the case of a previously found exact solution with an exponential potential and study the resulting mixing of adiabatic and isocurvature fluctuations in this example. We also discuss the possible relevance of the extra coupling in the perturbation equations for the process of generating an adiabatic component of the fluctuations spectrum from isocurvature perturbations without considering a later decay of the isocurvature component.Comment: 11 pages, 3 figures, one equation corrected, typos fixed, conclusions unchange

The Primordial Perturbation Spectrum from Various Expanding and Contracting Phases

In this paper, focusing on the case of single scalar field, we discuss various expanding and contracting phases generating primordial perturbations, and study the relation between the primordial perturbation spectrum from these phases and the parameter w of state equation in details. Furthermore, we offer an interesting classification for the primordial perturbation spectrum from various phases, which may have important implications for building an early universe scenario embedded in possible high energy theories.Comment: 5 pages, 3 eps figure

Upper bounds on wavepacket spreading for random Jacobi matrices

A method is presented for proving upper bounds on the moments of the position operator when the dynamics of quantum wavepackets is governed by a random (possibly correlated) Jacobi matrix. As an application, one obtains sharp upper bounds on the diffusion exponents for random polymer models, coinciding with the lower bounds obtained in a prior work. The second application is an elementary argument (not using multiscale analysis or the Aizenman-Molchanov method) showing that under the condition of uniformly positive Lyapunov exponents, the moments of the position operator grow at most logarithmically in time.Comment: final version, to appear in CM