Electric and Magnetic Fluxes in SU(2) Yang-Mills Theory

We measure the free energies in SU(2) of static fundamental charges and center monopoles. Dual to temporal center fluxes, the former provide a well-defined (dis)order parameter for deconfinement. In contrast, the monopole free energies vanish in the thermodynamic limit at all temperatures and are thus irrelevant for the transition.Comment: 3 pages, LaTeX2e (espcrc2.sty), 4 figures (epsfig), for Lattice2002(topology

Pension fund finance and sponsoring companies: Empirical evidence on theoretical hypotheses

This study presents empirical evidence on the influence of sponsoring companies on the funding and portfolio allocation of pension funds, an issue on which most extant literature is theoretical. We use a unique microdataset of 550 Dutch defined benefit company pension funds and 100 sponsoring firms over 1996-2005 to test the relevance of the main theoretical hypotheses, the first paper to do so in a comprehensive manner. We find that pension funds have lower cover ratios when (1) their sponsoring company is highly leveraged, (2) the fund’s return on assets is relatively low, and (3) the sponsoring firm is small. Further, defined benefit pension funds are found to invest more in shares when their sponsoring companies are highly leveraged. These links in general suggest higher risk in the sponsor leads to correspondingly higher risk in the fund, and warrant close attention by regulators

Cosmic D-Strings and Vortons in Supergravity

Recent developments in string inspired models of inflation suggest that D-strings are formed at the end of inflation. Within the supergravity model of D-strings there are 2(n-1) chiral fermion zero modes for a D-string of winding n. Using the bounds on the relic vorton density, we show that D-strings with winding number n>1 are more strongly constrained than cosmic strings arising in cosmological phase transitions. The D-string tension of such vortons, if they survive until the present, has to satisfy 8\pi G_N \mu \lesssim p 10^{-26} where p is the intercommutation probability. Similarly, D-strings coupled with spectator fermions carry currents and also need to respect the above bound. D-strings with n=1 do not carry currents and evade the bound. We discuss the coupling of D-strings to supersymmetry breaking. When a single U(1) gauge group is present, we show that there is an incompatibility between spontaneous supersymmetry breaking and cosmic D-strings. We propose an alternative mechanism for supersymmetry breaking, which includes an additional U(1), and might alleviate the problem. We conjecture what effect this would have on the fermion zero modes.Comment: 11 page

Racetrack inflation with matter fields and cosmic strings

We consider the coupling of racetrack inflation to matter fields as realized in the D3/D7 brane system. In particular, we investigate the possibility of cosmic string formation in this system. We find that strings can form before or at the onset of racetrack inflation is possible, but they are then inflated away. Furthermore, string formation at the end of inflation is prevented by the presence of the moduli sector. As a consequence, no strings survive racetrack inflation

Phyllotaxis and handedness in date palm (Phoenix dactylifera L.)

The present study had as objectives to measure the palm leaf divergence angle in the field, to determine the frequency of trees and offshoots showing clockwise and counterclockwise phyllotaxis, to establish the relationship between phyllotaxis of the mother tree and that of its offshoots, and, finally, to determine the effect of the divergence angle value on production. Materials and methods. The vegetal material was composed of four Moroccan cultivars of Phoenix dactylifera L. Observations were conducted in the south of Morocco on 20 trees per cultivar and four offshoots per tree. The divergence angle was measured on adult trees whereas phyllotaxic direction (clockwise or counterclockwise) was noted for both offshoots and adult trees. Results and discussion. This study showed that the phyllotaxic direction of the offshoots presents a clockwise or counterclockwise phyllotaxis independently of the mother plant. The divergence angle varied depending on the cultivar. This character is an interesting criterion, both for the selection of the best adapted cultivars for the marginal date palm growing regions, and for an optimal production

A cross-country comparison of market structures in European banking

In order to assess the effect of EMU on market conditions for banks based in countries which adopt the Single Currency, we use the H indicator suggested by Panzar and Rosse (1987). Our contribution is to assess results separately for large and small banks, and for interest income and total income as a dependent variable. From a panel of banks over the period 1992-1996, we provide evidence that European banking markets for large banks in the mid-1990s were still characterised by monopolistic competition, as compared to the United States. Regarding small banks, the level of competition appears to be even lower, especially in France and Germany. EMU would therefore imply a notable rise in competition for small banks in France and Germany, as well as an increase in competition for large banks, especially in Italy. JEL Classification: G21, L12banking, competition, contestability, EMU, panel data analysis

Brane-World Cosmology, Bulk Scalars and Perturbations

We investigate aspects of cosmology in brane world theories with a bulk scalar field. We concentrate on a recent model motivated from supergravity in singular spaces. After discussing the background evolution of such a brane-world, we present the evolution of the density contrast. We compare our results to those obtained in the (second) Randall-Sundrum scenario and usual 4D scalar-tensor theories.Comment: 29 pages, one figure, JHEP3-styl