Next-to-next-to-leading-order epsilon expansion for a Fermi gas at infinite scattering length

We extend previous work on applying the epsilon-expansion to universal properties of a cold, dilute Fermi gas in the unitary regime of infinite scattering length. We compute the ratio xi = mu/epsilon_F of chemical potential to ideal gas Fermi energy to next-to-next-to-leading order (NNLO) in epsilon=4-d, where d is the number of spatial dimensions. We also explore the nature of corrections from the order after NNLO.Comment: 28 pages, 14 figure

Models of G-spectra as presheaves of spectra

Let G be a finite group. We give Quillen equivalent models for the category of G-spectra as categories of spectrally enriched functors from explicitly described domain categories to nonequivariant spectra. Our preferred model is based on equivariant infinite loop space theory applied to elementary categorical data. It recasts equivariant stable homotopy theory in terms of point-set level categories of G-spans and nonequivariant spectra. We also give a more topologically grounded model based on equivariant Atiyah duality.Comment: 38 pages. v4. A number of relatively small changes and corrections. The introduction has been rewritten in response to suggestions from a referee. To make this paper more self-contained, section 4 on enriched model categories of G-spectra has been added. A new section 5 addresses a minor error in the previous version

Critical Exponents of the pure and random-field Ising models

We show that current estimates of the critical exponents of the three-dimensional random-field Ising model are in agreement with the exponents of the pure Ising system in dimension 3 - theta where theta is the exponent that governs the hyperscaling violation in the random case.Comment: 9 pages, 4 encapsulated Postscript figures, REVTeX 3.

Inhibition of pancreatic cancer cell growth in vitro by the tyrphostin group of tyrosine kinase inhibitors.

Tyrphostins are a group of low molecular weight synthetic inhibitors of protein tyrosine kinases (PTK). The intracellular domains of the receptors for epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), insulin-like growth factor 1 (IGF-1) possess PTK activity. Since EGF, TGF-alpha and IGF-1 are considered to play an important role in the proliferation of pancreatic cancer cells, we studied the effects of tyrphostins on the growth of three human pancreatic cancer cell lines (MiaPaCa-2, Panc-1 and CAV). The tyrphostins AG17, T23 and T47 all inhibited EGF and serum-stimulated DNA synthesis. AG17 was found to be the most potent of these agents and caused a dose-dependent but reversible inhibition of cell growth. Furthermore using an immunoblotting procedure we also found AG17 to inhibit EGF-induced tyrosine phosphorylation in the MiaPaCa-2 cell line. Tyrosine kinase inhibitors may prove to be useful agents for the treatment of pancreatic cancer

Human pancreatic cancer cell lines do not express receptors for somatostatin.

The in vivo administration of somatostatin (SS) or its analogues is capable of suppressing the growth of pancreatic cancer in experimental animals. We examined the effects of SS-14 and its analogue RC-160 on the in vitro growth of two human pancreatic cancer cell lines MiaPaCa-2 and Panc-1 stimulated with epidermal growth factor (EGF) or insulin-like growth factor 1 (IGF-1). Neither SS-14 nor RC-160 inhibited the growth of either cell line. In contrast RC-160 did inhibit the EGF-stimulated growth of a rat pancreatic cancer cell line AR42J. Binding studies with 125I-Tyr11 somatostatin revealed the presence of a single class of high affinity binding sites with a Kd of 0.20 +/- 0.05 nM and a Bmax of 2.1 +/- 0.26 pmoles mg-1 protein on AR42J but not displaceable binding was observed on MiaPaCa-2 or Panc-1. We conclude that lack of receptors accounts for the failure of SS-14 and RC-160 to influence the growth of human pancreatic cancer in vitro. These results, taken together with other findings, lead us to question the therapeutic efficacy of somatostatin and its analogues as mono-therapy in the treatment of human pancreatic cancer

Quantum phase transitions in the J-J' Heisenberg and XY spin-1/2 antiferromagnets on square lattice: Finite-size scaling analysis

We investigate the critical parameters of an order-disorder quantum phase transitions in the spin-1/2 $J-J'$ Heisenberg and XY antiferromagnets on square lattice. Basing on the excitation gaps calculated by exact diagonalization technique for systems up to 32 spins and finite-size scaling analysis we estimate the critical couplings and exponents of the correlation length for both models. Our analysis confirms the universal critical behavior of these quantum phase transitions: They belong to 3D O(3) and 3D O(2) universality classes, respectively.Comment: 7 pages, 3 figure

Identification sérologique rapide de Clostridium perfringens par une microtechnique d’immunodiffusion sur lame

Guillou J.-P., Chevrier L. Identification sérologique rapide de Clostridium perfringens par une microtechnique d’immunodiffusion sur lame. In: Bulletin de l'Académie Vétérinaire de France tome 125 n°5, 1972. pp. 239-249

The DICE calibration project: design, characterization, and first results

We describe the design, operation, and first results of a photometric calibration project, called DICE (Direct Illumination Calibration Experiment), aiming at achieving precise instrumental calibration of optical telescopes. The heart of DICE is an illumination device composed of 24 narrow-spectrum, high-intensity, light-emitting diodes (LED) chosen to cover the ultraviolet-to-near-infrared spectral range. It implements a point-like source placed at a finite distance from the telescope entrance pupil, yielding a flat field illumination that covers the entire field of view of the imager. The purpose of this system is to perform a lightweight routine monitoring of the imager passbands with a precision better than 5 per-mil on the relative passband normalisations and about 3{\AA} on the filter cutoff positions. The light source is calibrated on a spectrophotometric bench. As our fundamental metrology standard, we use a photodiode calibrated at NIST. The radiant intensity of each beam is mapped, and spectra are measured for each LED. All measurements are conducted at temperatures ranging from 0{\deg}C to 25{\deg}C in order to study the temperature dependence of the system. The photometric and spectroscopic measurements are combined into a model that predicts the spectral intensity of the source as a function of temperature. We find that the calibration beams are stable at the $10^{-4}$ level -- after taking the slight temperature dependence of the LED emission properties into account. We show that the spectral intensity of the source can be characterised with a precision of 3{\AA} in wavelength. In flux, we reach an accuracy of about 0.2-0.5% depending on how we understand the off-diagonal terms of the error budget affecting the calibration of the NIST photodiode. With a routine 60-mn calibration program, the apparatus is able to constrain the passbands at the targeted precision levels.Comment: 25 pages, 27 figures, accepted for publication in A&