Errors in Monte Carlo simulations using shift register random number generators

We report large systematic errors in Monte Carlo simulations of the tricritical Blume-Capel model using single spin Metropolis updating. The error, manifest as a $20\%$ asymmetry in the magnetisation distribution, is traced to the interplay between strong triplet correlations in the shift register random number generator and the large tricritical clusters. The effect of these correlations is visible only when the system volume is a multiple of the random number generator lag parameter. No such effects are observed in related models.Comment: 7 pages Revtex, 4 ps figures (uuencoded). Paper also available from: http://moses.physik.uni-mainz.de/~wilding/home_wilding.htm

Exact exchange optimized effective potential and self-compression of stabilized jellium clusters

In this work, we have used the exchange-only optimized effective potential in the self-consistent calculations of the density functional Kohn-Sham equations for simple metal clusters in stabilized jellium model with self-compression. The results for the closed-shell clusters of Al, Li, Na, K, and Cs with $N=$2, 8, 18, 20, 34, and 40 show that the clusters are 3% more compressed here than in the local spin density approximation. On the other hand, in the LSDA, neglecting the correlation results in a contraction by 1.4%.Comment: 7 pages, RevTex, 5 eps figures, 2 table

Magnetoelectric Cr_2 O_3 and relativity theory

Relativity theory is useful for understanding the phenomenology of the magnetoelectric effect of the antiferromagnet chromium sesquioxide Cr_2 O_3 in two respects: (i) One gets a clear idea about the physical dimensions of the electromagnetic quantities involved, in particular about the dimensions of the magnetoelectric moduli that we suggest to tabulate in future as dimensionless relative quantities; (ii) one can recognize and extract a temperature dependent, 4-dimensional pseudoscalar from the data of magnetoelectric experiments with Cr_2 O_3. This pseudoscalar piece of Cr_2 O_3 is odd under time reflections and parity transformations and is structurally related ("isomorphic") to the gyrator of electric network theory, the axion of particle physics, and the perfect electromagnetic conductor of electrical engineering.Comment: 9 pages latex, seminar at the Workshop on Magnetoelectric Interaction Phenomena in Crystals (MEIPIC-6), 25-28 Jan. 2009, Santa Barbara, US

It\u27s not just your dad and it\u27s not just your coach... The dual-role relationship in female tennis players

Parents and coaches were encouraged to keep their roles separate in order to promote optimal youth sport participation and avoid excessive and pressuring involvement (Gould, et al., 2008; Wolfenden & Hoyt, 2005). Despite these recommendations, the phenomenon of parents volunteering to coach their own children has dramatically increased (Brown, 1998). Managing the blurred boundaries of these coaching dual-role relationships throughout the athlete\u27s development is a delicate endeavor and remains unexplored in individual sports (Jowett, 2008; Weiss & Fretwell, 2005). Tennis has been identified as an ideal context to examine the dynamics of parenting and coaching relationships and is notorious for a high prevalence of parent-coaches (Agassi, 2009; Gould et al., 2008; Lauer, 2010). The purpose of this study was to examine the experiences of female tennis players who were coached by their fathers since childhood and then competed for an NCAA Division I college tennis team. All 318 NCAA Division I women\u27s tennis coaches were contacted and a purposive sampling method was used to identify eight eligible female tennis players willing to participate. A phenomenological interview approach was used to examine their experiences with the dual-role relationships and coaching transitions to college. A holistic narrative approach was used to build the trajectories of these relationships retrospectively. Findings were displayed following the four developmental periods where specific challenges emerged. Navigating the blurred boundaries was negatively influenced, to various degrees, by the participants\u27 dependency and urges to receive approval from their fathers, the presence of physical and emotional abuse, the lack of conflict resolution strategies, and the strain on family members. The coaching transitions helped normalize the father-daughter relationships and provided insight into the respective needs that were fulfilled through the dual-role relationships. One particular father-daughter dyad suggests that such relationships are not impossible to manage successfully and recommendations for parent-coaches are offered

Thermal Fluctuations in a Lamellar Phase of a Binary Amphiphile-Solvent Mixture: A Molecular Dynamics Study

We investigate thermal fluctuations in a smectic A phase of an amphiphile-solvent mixture with molecular dynamics simulations. We use an idealized model system, where solvent particles are represented by simple beads, and amphiphiles by bead-and-spring tetramers. At a solvent bead fraction of 20 % and sufficiently low temperature, the amphiphiles self-assemble into a highly oriented lamellar phase. Our study aims at comparing the structure of this phase with the predictions of the elastic theory of thermally fluctuating fluid membrane stacks [Lei et al., J. Phys. II 5, 1155 (1995)]. We suggest a method which permits to calculate the bending rigidity and compressibility modulus of the lamellar stack from the simulation data. The simulation results are in reasonable agreement with the theory

Mycophenolate mofetil inhibits lymphocyte binding and the upregulation of adhesion molecules in acute rejection of rat kidney allografts.

Mycophenolate mofetil (MMF) interacts with purine metabolism and possibly with the expression of adhesion molecules. In the present study, we analysed the expression of these molecules in transplanted kidney allografts treated with RS LBNF1 kidneys were orthotopically transplanted into Lewis rats and either treated with RS (20 mg/kg/day) or vehicle. Rats were harvested 3, 5 and 7 days following transplantation. For binding studies, fresh-frozen sections of transplanted kidneys were incubated with lymph node lymphocytes (LNL) derived from transplanted rats. Additionally, immunohistology was performed with various monoclonal antibodies. In general, MMF resulted in better preservation of graft structure by 7 days. Cellular infiltration and tubular atrophy were less pronounced. At day 3, macrophages were diminished in MMF-treated animals to a high extent, while the number of T cells was almost identical to that of controls. In addition, the number of cells positive for MHC class II and LFA-1 was reduced in the MMF-treated animals. These findings correlated with the binding results. Three days following engraftment, LNL bound to MMF-treated kidneys to a lesser extent compared to controls. In conclusion, MMF resulted in a markedly reduced leucocytic infiltrate, presumably based on a reduced expression of lymphocytic adhesion molecules and an interaction with macrophages