On the type species of Aubignyna and a description of A. hamblensis, a new microforaminifer from temperate shallow waters

The genus Aubignyna Margerel, 1970 (type A. mariei) was originally described from the upper Pliocene of NW France. Examination and re-illustration of topotypes of A. mariei Margerel, 1970, the holotype of Buccella planidorso Atkinson, 1969 (from the Recent of Cardigan Bay, Wales) and syntypes of Rotalia perlucida Heron-Allen and Earland, 1913 (from the Clare Island Survey, western Ireland) shows them to be conspecific. Consequently, the type-species of Aubignyna becomes R. perlucida, for which a lectotype is chosen. A new species of microforaminifera formally described here is assigned to Aubignyna and shown to occur in a wide range of intertidal - shallow subtidal, brackish - normal marine estuaries and lagoons in Europe and North America

Ash grains of the 1991 Mt. Pinatubo eruption as a tracer in Rose Bengal stained deep sea agglutinated foraminifera: How old is Freddy?

The use of volcanic ash particles (including dark-coloured grains) by agglutinated foraminifera that survived the 1991 eruption of Mt Pinatubo volcano provides a useful tracer to help determine growth rates and longevity in the deep sea. In the case of a specimen of Cyclammina pusilla Brady, the rate of chamber addition in this Rose Bengal stained sub-adult individual is three chambers over a timespan of five and one-half years

Easy on that trigger dad: a study of long term family photo retrieval

We examine the effects of new technologies for digital photography on people's longer term storage and access to collections of personal photos. We report an empirical study of parents' ability to retrieve photos related to salient family events from more than a year ago. Performance was relatively poor with people failing to find almost 40% of pictures. We analyze participants' organizational and access strategies to identify reasons for this poor performance. Possible reasons for retrieval failure include: storing too many pictures, rudimentary organization, use of multiple storage systems, failure to maintain collections and participants' false beliefs about their ability to access photos. We conclude by exploring the technical and theoretical implications of these findings

Vacuum polarization induced by a uniformly accelerated charge

We consider a point charge fixed in the Rindler coordinates which describe a uniformly accelerated frame. We determine an integral expression of the induced charge density due to the vacuum polarization at the first order in the fine structure constant. In the case where the acceleration is weak, we give explicitly the induced electrostatic potential.Comment: 13 pages, latex, no figures, to appear in Int. J. Theor. Phys

On the instability of classical dynamics in theories with higher derivatives

The development of instability in the dynamics of theories with higher derivatives is traced in detail in the framework of the Pais-Uhlenbeck fourth oder oscillator. For this aim the external friction force is introduced in the model and the relevant solutions to equations of motion are investigated. As a result, the physical implication of the energy unboundness from below in theories under consideration is revealed.Comment: 9 pages, no figures and no tables, revtex4; a few misprints are correcte

Adiabatic-Impulse approximation for avoided level crossings: from phase transition dynamics to Landau-Zener evolutions and back again

We show that a simple approximation based on concepts underlying the Kibble-Zurek theory of second order phase transition dynamics can be used to treat avoided level crossing problems. The approach discussed in this paper provides an intuitive insight into quantum dynamics of two level systems, and may serve as a link between the theory of dynamics of classical and quantum phase transitions. To illustrate these ideas we analyze dynamics of a paramagnet-ferromagnet quantum phase transition in the Ising model. We also present exact unpublished solutions of the Landau-Zener like problems.Comment: 12 pages & 6 figures, minor corrections, version accepted in Phys. Rev.