No relationship between fecundity and annual reproductive rate in bony fish

Background. There is still a widespread notion that bony fishes with high fecundities are more productive and therefore more resistant to overexploitation. The purpose of this study was to formally explore the relationship between fecundity and reproductive success expressed as maximum annual reproductive rate, i.e. the number of new spawners produced by existing spawners at low population densities. Material and methods. We used maximum annual reproductive rate from a recent study covering 49 species of bony fish; we used fecundity estimates from the published literature. Results. We found no significant relationship between fecundity (ranging from 368 to 10 million eggs) and maximum annual reproductive rate (ranging from 0.4 to 13.5 replacement spawners). Conclusion. Fecundity in oviparous bony fish without parental care has no relation with reproductive success. Apparently high fecundity in bony fish has evolved to counterbalance pre-adult mortality, as indicated by the fact that variance in fecundity is 3 orders of magnitude larger than variance in annual reproductive rate

The 125 GeV boson: A composite scalar?

Assuming that the 125 GeV particle observed at the LHC is a composite scalar and responsible for the electroweak gauge symmetry breaking, we consider the possibility that the bound state is generated by a non-Abelian gauge theory with dynamically generated gauge boson masses and a specific chiral symmetry breaking dynamics motivated by confinement. The scalar mass is computed with the use of the Bethe-Salpeter equation and its normalization condition as a function of the SU(N) group and the respective fermionic representation. If the fermions that form the composite state are in the fundamental representation of the SU(N) group, we can generate such light boson only for one specific number of fermions for each group. In the case of small groups, like SU(2) to SU(5), and two fermions in the adjoint representation we find that is quite improbable to generate such light composite scalar.Comment: 24 pages, 5 figures, discussion extended, references added; version to appear in Phys. Rev.

Soft Pomerons and the Forward LHC Data

Recent data from LHC13 by the TOTEM Collaboration on $\sigma_{tot}$ and $\rho$ have indicated disagreement with all the Pomeron model predictions by the COMPETE Collaboration (2002). On the other hand, as recently demonstrated by Martynov and Nicolescu (MN), the new $\sigma_{tot}$ datum and the unexpected decrease in the $\rho$ value are well described by the maximal Odderon dominance at the highest energies. Here, we discuss the applicability of Pomeron dominance through fits to the \textit{most complete set} of forward data from $pp$ and $\bar{p}p$ scattering. We consider an analytic parametrization for $\sigma_{tot}(s)$ consisting of non-degenerated Regge trajectories for even and odd amplitudes (as in the MN analysis) and two Pomeron components associated with double and triple poles in the complex angular momentum plane. The $\rho$ parameter is analytically determined by means of dispersion relations. We carry out fits to $pp$ and $\bar{p}p$ data on $\sigma_{tot}$ and $\rho$ in the interval 5 GeV - 13 TeV (as in the MN analysis). Two novel aspects of our analysis are: (1) the dataset comprises all the accelerator data below 7 TeV and we consider \textit{three independent ensembles} by adding: either only the TOTEM data (as in the MN analysis), or only the ATLAS data, or both sets; (2) in the data reductions to each ensemble, uncertainty regions are evaluated through error propagation from the fit parameters, with 90 \% CL. We argument that, within the uncertainties, this analytic model corresponding to soft Pomeron dominance, does not seem to be excluded by the \textit{complete} set of experimental data presently available.Comment: 10 pages, 4 figures, 1 table. Two paragraphs and four references added. Accepted for publication in Phys. Lett.