Sato-Crutchfield formulation for some Evolutionary Games

The Sato-Crutchfield equations are studied analytically and numerically. The Sato-Crutchfield formulation is corresponding to losing memory. Then Sato-Crutchfield formulation is applied for some different types of games including hawk-dove, prisoner's dilemma and the battle of the sexes games. The Sato-Crutchfield formulation is found not to affect the evolutionarily stable strategy of the ordinary games. But choosing a strategy becomes purely random independent on the previous experiences, initial conditions, and the rules of the game itself. Sato-Crutchfield formulation for the prisoner's dilemma game can be considered as a theoretical explanation for the existence of cooperation in a population of defectors.Comment: 9 pages, 3 figures, accepted for Int. J. Mod. Phys.

Testing saturation with diffractive jet production in deep inelastic scattering

We analyse the dissociation of a photon in diffractive deep inelastic scattering in the kinematic regime where the diffractive mass is much bigger than the photon virtuality. We consider the dominant q\bar{q}g component keeping track of the transverse momentum of the gluon which can be measured as a final-state jet. We show that the diffractive gluon-jet production cross-section is strongly sensitive to unitarity constraints. In particular, in a model with parton saturation, this cross-section is sensitive to the scale at which unitarity effects become important, the saturation scale. We argue that the measurement of diffractive jets at HERA in the limit of high diffractive mass can provide useful information on the saturation regime of QCD.Comment: 12 pages, 5 figures, misprints corrected, published versio

Propofol-Based Procedural Sedation with or without Low-Dose Ketamine in Children

Objective Examine comparative dosing, efficacy, and safety of propofol alone or with an initial, subdissociative dose of ketamine approach for deep sedation. Background Propofol is a sedative-hypnotic agent used increasingly in children for deep sedation. As a nonanalgesic agent, use in procedures (e.g., bone marrow biopsies/aspirations, renal biopsies) is debated. Our intensivist procedural sedation team sedates using one of two protocols: propofol-only (P-O) approach or age-adjusted dose of 0.25 or 0.5 mg/kg intravenous ketamine (K + P) prior to propofol. With either approach, an initial induction dose of 1 mg/kg propofol is recommended and then intermittent dosing throughout the procedure to achieve adequate sedation to safely and effectively perform the procedure. Approach: Retrospective evaluation of 754 patients receiving either the P-O or K + P approach to sedation. Results A total of 372 P-O group patients and 382 K + P group. Mean age (7.3 ± 5.5 years for P-O; 7.3 ± 5.4 years for K + P) and weight (30.09 ± 23.18 kg for P-O; 30.14 ± 24.45 kg for K + P) were similar in both groups (p = NS). All patients successfully completed procedures with a 16% combined incidence of hypoxia (SPO2 < 90%). Procedure time was 3 minutes longer for K + P group than P-O group (18.68 ± 15.13 minutes for K + P; 15.11 ± 12.77 minutes for P-O; p < 0.01), yet recovery times were 5 minutes shorter (17.04 ± 9.36 minutes for K + P; 22.17 ± 12.84 minutes for P-O; p < 0.01). Mean total dose of propofol was significantly greater in P-O than in K + P group (0.28 ± 0.20 mg/kg/min for K + P; 0.40 ± 0.26 mg/kg/min for P-O; p < 0.0001), and might explain the shorter recovery time. Conclusion Both sedation approaches proved to be well tolerated and equally effective. Addition of ketamine was associated with reduction in the recovery time, probably explained by the statistically significant decrease in the propofol dose

Coulomb blockade in silicon based structures at temperatures up to 50 K

Coulomb blockade has been observed in the current-voltage characteristics of structures fabricated in silicon germanium delta-doped material at temperatures up to 50 K. This is consistent with the estimated effective tunnel capacitance of 10 aF which is significantly smaller than the reported capacitances of tunnel junctions made from Al or GaAs/AlGaAs heterostructures

Mutual Fund Performance Advertising: Inherently and Materially Misleading?

Mutual fund companies routinely advertise the pastreturns of their strong-performing, actively-managedequity funds. These performance advertisements implythat the advertised high past returns are likely tocontinue. Indeed, investors flock to these funds despitehigh past returns being a poor predictor of high futurereturns. Thus, fund performance advertising is inherentlyand materially misleading and violates federal securitiesantifraud standards. In addition, the SEC-mandatedwarning in these advertisements that past performancedoes not guarantee future results fails to temper investors\u27focus on past returns.The SEC should do more to prevent investors from beingmisled by fund performance advertisements. It should atleast require a stronger warning that makes clear thathigh returns by actively-managed mutual funds generallydo not persist. The SEC should also seriously considerreinstating its prior prohibition of performanceadvertisements. Such a ban would help investors focus onmore important fund characteristics,such a fund\u27s costs,risk, and the extent to which the fund\u27s investmentobjective matches that of the investor

Reflectionless Potentials and PT Symmetry

Large families of Hamiltonians that are non-Hermitian in the conventional sense have been found to have all eigenvalues real, a fact attributed to an unbroken PT symmetry. The corresponding quantum theories possess an unconventional scalar product. The eigenvalues are determined by differential equations with boundary conditions imposed in wedges in the complex plane. For a special class of such systems, it is possible to impose the PT-symmetric boundary conditions on the real axis, which lies on the edges of the wedges. The PT-symmetric spectrum can then be obtained by imposing the more transparent requirement that the potential be reflectionless.Comment: 4 Page

Unitarization of Gluon Exchange Amplitudes and Rapidity Gaps at the Tevatron

Rapidity gaps between two hard jets at the Tevatron have been interpreted as being due to the exchange of two gluons which are in an overall color-singlet state. We show that this simple picture involves unitarity violating amplitudes. Unitarizing the gluon exchange amplitude leads to qualitatively different predictions for the fraction of $t$-channel color singlet exchange events in forward $qq$, $qg$ or $gg$ scattering, which better fit Tevatron data.Comment: 21 pages, Revtex, 7 postscript figures included via epsf.sty. Compressed postscript file of complete paper also available at http://pheno.physics.wisc.edu/pub/preprints/1998/madph-98-1024.ps.Z or at ftp://pheno.physics.wisc.edu/pub/preprints/1998/madph-98-1024.ps.

Germline genetic variation in prostate susceptibility does not predict outcomes in the chemoprevention trials PCPT and SELECT

Background The development of prostate cancer can be influenced by genetic and environmental factors. Numerous germline SNPs influence prostate cancer susceptibility. The functional pathways in which these SNPs increase prostate cancer susceptibility are unknown. Finasteride is currently not being used routinely as a chemoprevention agent but the long term outcomes of the PCPT trial are awaited. The outcomes of the SELECT trial have not recommended the use of chemoprevention in preventing prostate cancer. This study investigated whether germline risk SNPs could be used to predict outcomes in the PCPT and SELECT trial. Methods Genotyping was performed in European men entered into the PCPT trial (n = 2434) and SELECT (n = 4885). Next generation genotyping was performed using Affymetrix® Eureka™ Genotyping protocols. Logistic regression models were used to test the association of risk scores and the outcomes in the PCPT and SELECT trials. Results Of the 100 SNPs, 98 designed successfully and genotyping was validated for samples genotyped on other platforms. A number of SNPs predicted for aggressive disease in both trials. Men with a higher polygenic score are more likely to develop prostate cancer in both trials, but the score did not predict for other outcomes in the trial. Conclusion Men with a higher polygenic risk score are more likely to develop prostate cancer. There were no interactions of these germline risk SNPs and the chemoprevention agents in the SELECT and PCPT trials