Functional Co-substituted Poly[(amino acid ester)phosphazene] Biomaterials

The development of new and improved biomaterials is essential for tissue engineering and regenerative medicine applications. Amino acid-based polyphosphazenes are being explored as scaffold materials for tissue engineering applications due to their non-toxic degradation products and tunable material properties. This work focuses on the synthesis of non-functional and novel functional poly[(amino acid ester)phosphazene]s using a facile method of thermal ring opening polymerization followed by one-pot room temperature substitution. The family of polyphosphazenes developed in this work is based on L-alanine (PNEAs), L-phenylalanine (PNEFs), and L-methionine (PNEMs) with L-glutamic acid imparting the functionality. Characterization of these materials demonstrated that the one-pot substitution was successful in developing mono- and co-substituted poly[(amino acid ester)phosphazene]s. Cytotoxicity studies on two-dimensional films showed these materials to be compatible with NIH-3T3 fibroblasts over the five-day study. The PNEFs also showed significantly enhanced cell viability over tissue culture polystyrene at day 1 (

Contribution of Scalar Loops to the Three-Photon Decay of the Z

I corrected 3 mistakes from the first version: that were an omitted Feynman integration in the function f^3_{ij}, a factor of 2 in front of log f^3_{ij} in eq.2 and an overall factor of 2 in Fig.1 c). The final result is changed drastically. Doing an expansion in the Higgs mass I show that the matrix element is identically 0 in the order (MZ/MH)^2, which is due to gauge invariance. Left with an amplitude of the order (MZ/MH)^4 the final result is that the scalar contribution to this decay rate is several orders of magnitude smaller than those of the W boson and fermions.Comment: 6 pages, plain Tex, 1 figure available under request via fax or mail, OCIP/C-93-5, UQAM-PHE-93/0

Detecting and Studying Higgs Bosons at a Photon-Photon Collider

We examine the potential for detecting and studying Higgs bosons at a photon-photon collider facility associated with a future linear collider. Our study incorporates realistic \gam\gam luminosity spectra based on the most probable available laser technology. Results include detector simulations. We study the cases of: a) a SM-like Higgs boson; b) the heavy MSSM Higgs bosons; c) a Higgs boson with no $WW/ZZ$ couplings from a general two Higgs doublet model.Comment: 52 pages, 26 figures, revised version with new appendi

H-alpha Kinematics of the SINGS Nearby Galaxies Survey. II

This is the second part of an H-alpha kinematics follow-up survey of the Spitzer Infrared Nearby Galaxies Survey (SINGS) sample. The aim of this program is to shed new light on the role of baryons and their kinematics and on the dark/luminous matter relation in the star forming regions of galaxies, in relation with studies at other wavelengths. The data for 37 galaxies are presented. The observations were made using Fabry-Perot interferometry with the photon-counting camera FaNTOmM on 4 different telescopes, namely the Canada-France-Hawaii 3.6m, the ESO La Silla 3.6m, the William Herschel 4.2m, and the Observatoire du mont Megantic 1.6m telescopes. The velocity fields are computed using custom IDL routines designed for an optimal use of the data. The kinematical parameters and rotation curves are derived using the GIPSY software. It is shown that non-circular motions associated with galactic bars affect the kinematical parameters fitting and the velocity gradient of the rotation curves. This leads to incorrect determinations of the baryonic and dark matter distributions in the mass models derived from those rotation curves.Comment: 18 pages, 5 figures, 4 tables. Accepted for publication in MNRAS. All high-res. figures are available at http://www.astro.umontreal.ca/fantomm/singsII

The Higgs - photon - Z boson coupling revisited

We analyze the coupling of CP-even and CP-odd Higgs bosons to a photon and a Z boson in extensions of the Standard Model. In particular, we study in detail the effect of charged Higgs bosons in two-Higgs doublet models, and the contribution of SUSY particle loops in the minimal supersymmetric extension of the Standard Model. The Higgs-$\gamma Z$ coupling can be measured in the decay $Z \to \gamma$+Higgs at $e^+e^-$ colliders running on the Z resonance, or in the reverse process Higgs $\to Z \gamma$ with the Higgs boson produced at LHC. We show that a measurement of this coupling with a precision at the percent level, which could be the case at future $e^+e^-$ colliders, would allow to distinguish between the lightest SUSY and standard Higgs bosons in large areas of the parameter space.Comment: 18 pages LaTex + 7 figures (ps). Typo corrected in eq.(5

An improved method for statistical studies of the internal kinematics of HII regions: the case of M 83

We present the integrated Halpha emission line profile for 157 HII regions in the central 3.4' x 3.4' of the galaxy M 83 (NGC 5236). Using the Fabry-Perot interferometer GHaFaS, on the 4.2 m William Herschel on La Palma, we show the importance of a good characterization of the instrumental response function for the study of line profile shapes. The luminosity-velocity dispersion relation is also studied, and in the log(L)-log(sigma) plane we do not find a linear relation, but an upper envelope with equation log(L)=0.9 *log(sigma)+38.1. For the adopted distance of 4.5 Mpc, the upper envelope appears at the luminosity L=10^38.5 ergs, in full agreement with previous studies of other galaxies, reinforcing the idea of using HII regions as standard candles.Comment: 13 pages, 9 figures, accepted for publication in MNRA

Supersymmetry Relations Between Contributions To One-Loop Gauge Boson Amplitudes

We apply ideas motivated by string theory to improve the calculational efficiency of one-loop weak interaction processes with massive external gauge bosons. In certain cases ``supersymmetry'' relations between diagrams with a fermion loop and with a gauge boson loop hold. This is explicitly illustrated for a particular one-loop standard model process with four-external gauge bosons. The supersymmetry relations can be used to provide further significant improvements in calculational efficiency.Comment: 21 pages of plain TeX + 5 PostScript figures (compressed and uuencoded), UCLA/93/TEP/36 and DTP/93/8

Interacting mindreaders

Could interacting mindreaders be in a position to know things which they would be unable to know if they were manifestly passive observers? This paper argues that they could. Mindreading is sometimes reciprocal: the mindreader's target reciprocates by taking the mindreader as a target for mindreading. The paper explains how such reciprocity can significantly narrow the range of possible interpretations of behaviour where mindreaders are, or appear to be, in a position to interact. A consequence is that revisions and extensions are needed to standard theories of the evidential basis of mindreading. The view also has consequences for understanding how abilities to interact combined with comparatively simple forms of mindreading may explain the emergence, in evolution or development, of sophisticated forms of social cognition

Callous-unemotional traits, low cortisol reactivity and physical aggression in children: findings from the Wirral Child Health and Development Study

Callous-unemotional (CU) traits are thought to confer risk for aggression via reduced amygdala responsivity to distress cues in others. Low cortisol reactivity is thought to confer risk for aggression via reduced arousal and this effect may be confined to boys. We tested the hypothesis that the association between childhood CU traits and aggression would be greatest in the absence of the inhibitory effects of cortisol reactivity, and that this effect would be sex dependent. Participants were 283 members of a stratified subsample within an epidemiological longitudinal cohort (WCHADS). Cortisol reactivity to a social stressor was assessed at 5 years. CU traits were reported by mothers at 5 years, and physical aggression by mothers and teachers at age 7. Results showed that CU traits were associated with elevated aggression at 7 years controlling for earlier aggression. There was no main effect of cortisol reactivity on regression. The association between CU traits and aggression was moderated by cortisol reactivity (p = .011) with a strong association between CU traits and aggression in the presence of low reactivity, and a small and non-significant association in the presence of high reactivity. This association was further moderated by child sex (p = .041) with the joint effect of high CU traits and low cortisol reactivity seen only in boys (p = .016). We report first evidence that a combined deficit in inhibitory processes associated with CU traits and low cortisol reactivity increases risk for childhood aggression, in a sex-dependent manner

Chargino-Sneutrino Production in Electron-Photon Collisions

We study the production of charginos and sneutrinos in electron-photon collisions within the minimal supersymmetric standard model (MSSM). The high energy photons can be generated by Compton backscattering of intense laser pulses off one of the beams of the Next Linear Collider (NLC). This process could offer a significant opportunity to identify sneutrinos, which exclusively decay invisibly into a neutrino and the LSP, since the cross sections are two orders of magnitude higher than for the radiative production of invisible sneutrinos. For three scenarios of gaugino-higgsino mixing the cross sections and polarization asymmetries are computed and the resulting signatures are compared with the SM background.Comment: 22 pages, REVTEX, including 11 Postscript figures, complete psfile also available at ftp://ftp.physik.uni-wuerzburg.de/pub/preprint/1996/WUE-ITP-96-005.ps.gz ; revised version: number of figures reduced, minor changes in text, final versio