Role of Electon Excitation and Nature of Molecular Gas in Cluster Central Elliptical Galaxies

We present observations in CO(3-2) that, combined with previous observations in CO(2-1), constrain the physical properties of the filamentary molecular gas in the central $\sim$6.5 kpc of NGC 1275, the central giant elliptical galaxy of the Perseus cluster. We find this molecular gas to have a temperature $\gtrsim 20$ K and a density $\sim$$10^2$-$10^4 {\rm \ cm^{-3}}$, typically warmer and denser than the bulk of Giant Molecular Clouds (GMCs) in the Galaxy. Bathed in the harsh radiation and particle field of the surrounding intracluster X-ray gas, the molecular gas likely has a much higher ionization fraction than that of GMCs. For an ionization fraction of $\sim$$10^{-4}$, similar to that of Galactic diffuse ($\lesssim 250 {\rm \ cm^{-3}}$) partially-molecular clouds that emit in HCN(1-0) and HCO$^+$(1-0), we show that the same gas traced in CO can produce the previously reported emissions in HCN(3-2), HCO$^+$(3-2), and CN(2-1) from NGC 1275; the dominant source of excitation for all the latter molecules is collisions with electrons. To prevent collapse, as evidenced by the lack of star formation in the molecular filaments, they must consist of thin strands that have cross-sectional radii $\lesssim$0.2-2 pc if supported solely by thermal gas pressure; larger radii are permissible if turbulence or poloidal magnetic fields provide additional pressure support. We point out that the conditions required to relate CO luminosities to molecular gas masses in our Galaxy are unlikely to apply in cluster central elliptical galaxies. Rather than being virialized structures analogous to GMCs, we propose that the molecular gas in NGC 1275 comprises pressure-confined structures created by turbulent flows.Comment: 41 pages, 1 table, 12 figures; accepted by Ap

Validation of the 3-under-2 principle of cell wall growth in Gram-positive bacteria by simulation of a simple coarse-grained model

The aim of this work is to propose a first coarse-grained model of Bacillus subtilis cell wall, handling explicitly the existence of multiple layers of peptidoglycans. In this first work, we aim at the validation of the recently proposed "three under two" principle.Comment: Revised introduction, results unchange

Green Currents for Meromorphic Maps of Compact K\"ahler Manifolds

We consider the dynamics of meromorphic maps of compact K\"ahler manifolds. In this work, our goal is to locate the non-nef locus of invariant classes and provide necessary and sufficient conditions for existence of Green currents in codimension one.Comment: Statement of Theorem 1.5 is slightly improved. Proposition 5.2 and Theorem 5.3 are adde

Co-Morbidity of Pituitary Adenoma and Frontal Convexity Meningioma: A Case Report and Review of the Literature

Instruction: The current study reports a woman with pituitary adenoma and frontal convexity meningioma that was detected accidentially. To the best of our knowledge, this case is considered as a rare clinical scenario.Case presentation: A 37 years old woman suffering from amenorrhea and galactorrhea had her detail investigation showed hyperprolactinemia. The patient was diagnosed with a prolactinoma, and a frontal convexity meningioma was discovered on MRI. The prolactinoma controlled with Bromocriptine therapy, while the meningioma monitored through medical observation. After two months of pharmaceutical medication, her symptoms improved with the decrease in serum prolactin.Conclusion: Thanks to sophisticated MRI techniques, meningioma and prolactinoma were incidentally detected. It should be noted that co-morbidity of prolactinoma and meningioma is very rare. The mechanism of the association between these two familiar types of intracranial tumors has not yet been clarified, which indicates the need for further studies to offer possible targeted treatment for patients.Keyword: Meningiomas; Prolactinomas; Pituitary adenomas

Sur les exposants de Lyapounov des applications meromorphes

Let f be a dominating meromorphic self-map of a compact Kahler manifold. We give an inequality for the Lyapounov exponents of some ergodic measures of f using the metric entropy and the dynamical degrees of f. We deduce the hyperbolicity of some measures.Comment: 27 pages, paper in french, final version: to appear in Inventiones Mat

Resonant Diffraction Radiation from an Ultrarelativistic Particle Moving Close to a Tilted Grating

A simple model for calculating the diffraction radiation characteristics from an ultrarelativistic charged particle moving close to a tilted ideally conducting strip is developed. Resonant diffraction radiation (RDR) is treated as a superposition of the radiation fields for periodically spaced strips. The RDR characteristics have been calculated as a function of the number of grating elements, tilted angle, and initial particle energy. An analogy with both the resonant transition radiation in absorbing medium and the parametric X-ray radiation is noted.Comment: 17 pages, 12 figures, RevTe

Population of isomers in decay of the giant dipole resonance

The value of an isomeric ratio (IR) in N=81 isotones ($^{137}$Ba, $^{139}$Ce, $^{141}$Nd and $^{143}$Sm) is studied by means of the ($\gamma, n)$ reaction. This quantity measures a probability to populate the isomeric state in respect to the ground state population. In ($\gamma, n)$ reactions, the giant dipole resonance (GDR) is excited and after its decay by a neutron emission, the nucleus has an excitation energy of a few MeV. The forthcoming $\gamma$ decay by direct or cascade transitions deexcites the nucleus into an isomeric or ground state. It has been observed experimentally that the IR for $^{137}$Ba and $^{139}$Ce equals about 0.13 while in two heavier isotones it is even less than half the size. To explain this effect, the structure of the excited states in the energy region up to 6.5 MeV has been calculated within the Quasiparticle Phonon Model. Many states are found connected to the ground and isomeric states by $E1$, $E2$ and $M1$ transitions. The single-particle component of the wave function is responsible for the large values of the transitions. The calculated value of the isomeric ratio is in very good agreement with the experimental data for all isotones. A slightly different value of maximum energy with which the nuclei rest after neutron decay of the GDR is responsible for the reported effect of the A-dependence of the IR.Comment: 16 pages, 4 Fig