A quadriocellar scoliid wasp (Hymenoptera, Scoliidae) from Mallorca, with a brief account of supernumerary ocelli in insects

A remarkable teratological female of Megascolia (Regiscolia) maculata flavifrons (Fabricius, 1775) (Scoliidae: Scoliinae: Scoliini) with a supernumerary median ocellus is described and illustrated. While supernumerary ocelli have been reported before from Diptera, Orthoptera, and Hymenoptera, this is the first record of such a malformation from a scoliid wasp. Four other teratological scoliid wasps have been reported in the literature but all were gynandromorphs. A brief summary of known records of supernumerary ocelli among insects is provided

The wasp larva's last supper: 100 million years of evolutionary stasis in the larval development of rhopalosomatid wasps (Hymenoptera: Rhopalosomatidae)

Rhopalosomatidae are an unusual family of wasps (Hymenoptera: Aculeata) comprising less than 100 species found in the tropics and subtropics of all continents except Europe and Antarctica. Whereas some species resemble nocturnal Ichneumonidae, others might be mistaken for spider wasps or different groups of brachypterous Hymenoptera. Despite their varied morphology, all members of the family supposedly develop as larval ectoparasitoids of crickets (Orthoptera: Grylloidea). Here, we report on the first record of a fossil rhopalosomatid larva which was discovered in mid-Cretaceous amber from northern Myanmar (Burma). The larva is attached to the lateral side of a cricket between the metafemur and the abdomen, impacting the natural position of the hind leg, exactly as documented for modern species. Additionally, the larval gestalt is strikingly similar to those of extant forms. These observations imply that this behavioral specialization, e.g., host association and positioning on host, likely evolved in the stem of the family at least 100 million years ago

Interference in above-threshold-ionization electron distributions from molecules

We present quantum-mechanical studies on above-threshold ionization of molecular ions in two and three dimensions. The momentum distributions show signatures of interfering emissions from the molecular centers. These structures deviate from a simple double-slit model that ignores the electron-ion interaction, but they are reproduced by an eikonal model. Such distortions of the interference pattern are partly responsible for the absence of clear interference patterns in the angle-integrated electron energy spectra. © 2011 American Physical Society.Studienstiftung des Deutschen VolkesDFGEU Marie Curie Initial Training Network/FASTQUAS

Vibrational-state and isotope dependence of high-order harmonic generation in water molecules

We report calculations on high-order harmonic generation in water molecules. Spectra are determined for various initial vibrational states of H2O and its isotope D2O. It is demonstrated that the ratio of the spectra for D2O and H2O is close to unity when the initial state is the vibronic ground state, indicating that nuclear dynamics is of minor importance. For vibrationally excited initial states, the high-harmonic intensities show a clear dependence on both the initial-state quantum number and the isotopic species. © 2010 The American Physical Society

Noiseless limit of a ferrofluid ratchet

The noiseless limit of a thermal ratchet device using ferrofluids is studied in detail. Contrary to previous claims it is proved that no directed transport can occur in this model in the absence of fluctuations.Comment: 10 pages, 2 figure

Adiabaticity in the lateral electron-momentum distribution after strong-field ionization

By solving the time-dependent Schrödinger equation for atoms in short laser pulses of different polarizations, it is shown that in strong-field ionization without rescattering, the lateral width of the electron-momentum distribution corresponds adiabatically to the instantaneous laser field on a sub-laser-cycle time scale, as expected in pure tunneling ionization. In contrast to the distributions along the polarization direction, the width is affected little by depletion or Coulomb effects. © 2012 American Physical Society.DF

Role of interactions in ferrofluid thermal ratchets

Orientational fluctuations of colloidal particles with magnetic moments may be rectified with the help of external magnetic fields with suitably chosen time dependence. As a result a noise-driven rotation of particles occurs giving rise to a macroscopic torque per volume of the carrier liquid. We investigate the influence of mutual interactions between the particles on this ratchet effect by studying a model system with mean-field interactions. The stochastic dynamics may be described by a nonlinear Fokker-Planck equation for the collective orientation of the particles which we solve approximately by using the effective field method. We determine an interval for the ratio between coupling strength and noise intensity for which a self-sustained rectification of fluctuations becomes possible. The ratchet effect then operates under conditions for which it were impossible in the absence of interactions.Comment: 18 pages, 10 figure