Dispersion Theory and the Low Energy Constants for Neutral Pion Photoproduction

The relativistic amplitudes of pion photoproduction are evaluated by dispersion relations at t=const. The imaginary parts of the amplitudes are taken from the MAID model covering the absorption spectrum up to center-of-mass energies W = 2.2 GeV. For sub-threshold kinematics the amplitudes are expanded in powers of the two independent variables \nu and t related to energy and momentum transfer. Subtracting the loop corrections from this power series allows one to determine the counter terms of covariant baryon chiral perturbation theory. The proposed continuation of the amplitudes into the unphysical region provides a unique framework to derive the low-energy constants to any given order as well as an estimate of the higher order terms by global properties of the absorption spectrum.Comment: 13 pages, 6 figures, 5 table

Light clusters in nuclear matter of finite temperature

We investigate properties and the distribution of light nuclei (A<4) in symmetric nuclear matter of finite temperature within a microscopic framework. For this purpose we have solved few-body Alt-Grassberger-Sandhas type equations for quasi-nucleons that include self-energy corrections and Pauli blocking in a systematic way. In a statistical model we find a significant influence in the composition of nuclear matter if medium effects are included in the microscopic calculation of nuclei. If multiplicities are frozen out at a certain time (or volume), we expect significant consequences for the formation of light fragments in a heavy ion collision. As a consequence of the systematic inclusion of medium effects the ordering of multiplicities becomes opposite to the law of mass action of ideal components. This is necessary to explain the large abundance of $\alpha$-particles in a heavy ion collision that are otherwise largely suppressed in an ideal equilibrium scenario.Comment: 9 pages, 9 figures, epja-style file

Evoked and Spontaneous Pain Assessment During Tooth Pulp Injury

Injury of the tooth pulp is excruciatingly painful and yet the receptors and neural circuit mechanisms that transmit this form of pain remain poorly defined in both the clinic and preclinical rodent models. Easily quantifiable behavioral assessment in the mouse orofacial area remains a major bottleneck in uncovering molecular mechanisms that govern inflammatory pain in the tooth. In this study we sought to address this problem using the Mouse Grimace Scale and a novel approach to the application of mechanical Von Frey hair stimuli. We use a dental pulp injury model that exposes the pulp to the outside environment, a procedure we have previously shown produces inflammation. Using RNAscope technology, we demonstrate an upregulation of genes that contribute to the pain state in the trigeminal ganglia of injured mice. We found that mice with dental pulp injury have greater Mouse Grimace Scores than sham within 24 hours of injury, suggestive of spontaneous pain. We developed a scoring system of mouse refusal to determine thresholds for mechanical stimulation of the face with Von Frey filaments. This method revealed that mice with a unilateral dental injury develop bilateral mechanical allodynia that is delayed relative to the onset of spontaneous pain. This work demonstrates that tooth pain can be quantified in freely behaving mice using approaches common for other types of pain assessment. Harnessing these assays in the orofacial area during gene manipulation should assist in uncovering mechanisms for tooth pulp inflammatory pain and other forms of trigeminal pain. © 2020, The Author(s)

Common European Sales Law (CESL) and Private International Law: Some Critical Remarks

This article is an updated and revised version of the contribution published by the author in XI Anuario Español de Derecho Internacional Privado, 2011, 25-61, under the title: “La Propuesta de Reglamento relativo a una normativa común de compraventa europea y el Derecho internacional privado”.La Propuesta de Reglamento del Parlamento Europeo y del Consejo relativo a una normativa común de compraventa europea de 11 de octubre de 2011 (PCESL) introduce una reglamentación material para algunas compraventas transfronterizas que no desplaza la aplicación de las normas de conflicto (en particular de las contenidas de los Reglamentos “Roma I” y “Roma II”). Al contrario, el instrumento opcional contenido en la Propuesta de Reglamento (CESL) presupone la aplicación de la ley de un Estado miembro, como lex contractus. Una vez escogida por las partes, la CESL desplaza a las normas internas cobre compraventa de la ley del Estado miembro. Esta opción del legislador comunitario plantea numerosos problemas e interrogantes acerca de las relaciones entre la CESL y las normas de Derecho internacional privado y en torno a su coexistencia con otros convenios internacionales y el propio acervo comunitario. El análisis de estas relaciones es el objeto del presente estudio, que permite concluir con una valoración negativa de la competitividad internacional de este nuevo instrumento comunitario.The Proposal for a Regulation of the European Parliament and of the Council on a Common European Sales Law of 11 October 2011 (PCESL) introduces a substantive regulation for some cross-border sales contracts that does not displace the application of conflict-of-laws rules (especially those included in “Rome I” and “Rome II” Regulations). On the contrary, the optional instrument included in the Proposal (CESL) presupposes the application of the law of a Member State as lex contractus. Once the parties have chosen the CESL, this regime prevails over the internal rules on sales contracts of the law of that Member State. The formula used by the European legislator gives rise to many concerns and questions about the relationships between the CESL and the conflict-of-laws rules and about its cohabitation with other international conventions and the European acquis itself. The analysis of these relationships is the subject of this article, which concludes with a negative assessment on the international competitiveness of the new European instrument

Quasiparticle Description of the QCD Plasma, Comparison with Lattice Results at Finite T and Mu

We compare our 2+1 flavor, staggered QCD lattice results with a quasiparticle picture. We determine the pressure, the energy density, the baryon density, the speed of sound and the thermal masses as a function of T and $\mu_B$. For the available thermodynamic quantities the difference is a few percent between the results of the two approaches. We also give the phase diagram on the $\mu_B$--T plane and estimate the critical chemical potential at vanishing temperature.Comment: 13 pages, 10 figure

Enhanced absorption Hanle effect on the Fg=F->Fe=F+1 closed transitions

We analyse the Hanle effect on a closed $F_g\to F_e=F_g+1$ transition. Two configurations are examined, for linear- and circular-polarized laser radiation, with the applied magnetic field collinear to the laser light wavevector. We describe the peculiarities of the Hanle signal for linearly-polarized laser excitation, characterized by narrow bright resonances at low laser intensities. The mechanism behind this effect is identified, and numerical solutions for the optical Bloch equations are presented for different transitions.Comment: to be published in J. Opt. B, special issue on Quantum Coherence and Entanglement (February 2001

Reduction of the Ordered Magnetic Moment and its Relationship to Kondo Coherence in Ce₁₋ₓLaₓCu₂Ge₂

The microscopic details of the suppression of antiferromagnetic order in the Kondo-lattice series Ce1-xLaxCu2Ge2 due to nonmagnetic dilution by La are revealed through neutron diffraction results for x = 0.20, 0.40, 0.75, and 0.85. Magnetic Bragg peaks are found for 0.20 ≤ x ≤ 0.75, and both the Néel temperature TN and the ordered magnetic moment per Ce μ linearly decrease with increasing x. The reduction in μ points to strong hybridization of the increasingly diluted Ce 4f electrons, and we find a remarkable quadratic dependence of μ on the Kondo-coherence temperature. We discuss our results in terms of local-moment- versus itinerant-type magnetism and mean-field theory and show that Ce1-xLaxCu2Ge2 provides an exceptional opportunity to quantitatively study the multiple magnetic interactions in a Kondo lattice

Single-photon-emitting diodes: a review

Compact and reliable sources of non-classical light could find many applications in emerging technologies such as quantum cryptography, quantum imaging and also in fundamental tests of quantum physics. Single self-assembled quantum dots have been widely studied for this reason, but the vast majority of reported work has been limited to optically excited sources. Here we discuss the progress made so far, and prospects for, electrically driven single-photon-emitting diodes (SPEDs).Comment: 13 pages, 10 figure