Length-weight relationships for some important forage crustaceans from South Africa

The diet of marine animals is usually determined by stomach content analysis. Although partially digested prey fragments can often be identified to species level, it is difficult to estimate the original mass of the prey organism. This information, however, is essential for calculating both the total food intake as well as the relative contribution of each prey item. In this study we present regression equations that can be used to estimate the original mass of 18 common South African crustaceans from various indigestible fragments such as the carapace (length and width), chelae (length and width of left and right dactylus) and eye (length and width)

Slaughterhouse zoonoses: Are workers reservoirs of zoonotic disease?

Slaughterhouse workers are considered a high risk group for zoonotic disease due to increased contact with animals, animal products and excreta. Globally, slaughterhouse workers have been shown to have an increased seroprevalence to zoonotic pathogens, though no such studies exist in Kenya. Slaughterhouse workers may also act as reservoirs of these zoonotic organisms and asymptomatic carriage of pathogenic bacteria has been demonstrated. This study aimed to determine the carriage of enteropathogens in slaughterhouse workers in rural western Kenya and to determine if there was asymptomatic carriage of Staphylococcus aureus specifically Methicillin Resistant S. aureus (MRSA). This study was conducted in the Lake Victoria Crescent region of western Kenya. Five hundred slaughterhouse workers from this region were asked a comprehensive questionnaire regarding risk factors for zoonotic disease, faecal samples were collected for examination and culture and a nasal swab was cultured for S. aureus. This study reports on the seroprevalence of Salmonella spp, Shigella spp, pathogenic Escherichia coli and Campylobacter spp. in these individuals as well as reporting the nasal carriage of S. aureus and MRSA. This is the first community based study regarding S. aureus and MRSA in Kenya. The asymptomatic carriage of these organisms in slaughterhouse workers highlights a reservoir that may be important in the dissemination of these pathogens. The study further comments on the risk factors for infection with these pathogens and suggestions are made for simple hygiene interventions that can reduce disease in slaughterhouse workers and dissemination to the wider communit

Moduli Instability in Warped Compactifications of the Type IIB Supergravity

We show that the conifold and deformed-conifold warped compactifications of the ten-dimensional type IIB supergravity, including the Klebanov-Strassler solution, are dynamically unstable in the moduli sector representing the scale of a Calabi-Yau space, although it can be practically stable for a quite long time in a region with a large warp factor. This instability is associated with complete supersymmetry breaking except for a special case and produces significant time-dependence in the structure of the four-dimensional base spacetime as well as of the internal space.Comment: 24 pages, no figure. Typos corrected, and some arguments in section 5 are adde

Potential and mass-matrix in gauged N=4 supergravity

We discuss the potential and mass-matrix of gauged N=4 matter coupled supergravity for the case of six matter multiplets, extending previous work by considering the dependence on all scalars. We consider all semi-simple gauge groups and analyse the potential and its first and second derivatives in the origin of the scalar manifold. Although we find in a number of cases an extremum with a positive cosmological constant, these are not stable under fluctuations of all scalar fields.Comment: 28 pages, LaTe

Holographic Dark Energy Model and Scalar-Tensor Theories

We study the holographic dark energy model in a generalized scalar tensor theory. In a universe filled with cold dark matter and dark energy, the effect of potential of the scalar field is investigated in the equation of state parameter. We show that for a various types of potentials, the equation of state parameter is negative and transition from deceleration to acceleration expansion of the universe is possible.Comment: 11 pages, no figure. To appear in General Relativity and Gravitatio

Can induced gravity isotropize Bianchi I, V, or IX Universes?

We analyze if Bianchi I, V, and IX models in the Induced Gravity (IG) theory can evolve to a Friedmann--Roberson--Walker (FRW) expansion due to the non--minimal coupling of gravity and the scalar field. The analytical results that we found for the Brans-Dicke (BD) theory are now applied to the IG theory which has $\omega \ll 1$ ($\omega$ being the square ratio of the Higgs to Planck mass) in a cosmological era in which the IG--potential is not significant. We find that the isotropization mechanism crucially depends on the value of $\omega$. Its smallness also permits inflationary solutions. For the Bianch V model inflation due to the Higgs potential takes place afterwads, and subsequently the spontaneous symmetry breaking (SSB) ends with an effective FRW evolution. The ordinary tests of successful cosmology are well satisfied.Comment: 24 pages, 5 figures, to be published in Phys. Rev. D1

Tachyonic Inflation in a Warped String Background

We analyze observational constraints on the parameter space of tachyonic inflation with a Gaussian potential and discuss some predictions of this scenario. As was shown by Kofman and Linde, it is extremely problematic to achieve the required range of parameters in conventional string compactifications. We investigate if the situation can be improved in more general compactifications with a warped metric and varying dilaton. The simplest examples are the warped throat geometries that arise in the vicinity of of a large number of space-filling D-branes. We find that the parameter range for inflation can be accommodated in the background of D6-branes wrapping a three-cycle in type IIA. We comment on the requirements that have to be met in order to realize this scenario in an explicit string compactification.Comment: Latex, JHEP class, 20 pages, 4 figures. v2: references added, small error in section 7 corrected, published versio

Non-minimally Coupled Tachyonic Inflation in Warped String Background

We show that the non-minimal coupling of tachyon field to the scalar curvature, as proposed by Piao et al, with the chosen coupling parameter does not produce the effective potential where the tachyon field can roll down from T=0 to large $T$ along the slope of the potential. We find a correct choice of the parameters which ensures this requirement and support slow-roll inflation. However, we find that the cosmological parameter found from the analysis of the theory are not in the range obtained from observations. We then invoke warped compactification and varying dilaton field over the compact manifold, as proposed by Raeymaekers, to show that in such a setup the observed parameter space can be ensured.Comment: minor typos corrected and references adde