Least action description of dynamic pairing correlations in the fission of Curium and Californium isotopes based on the Gogny energy density functional

The impact of dynamic pairing correlations and their interplay with Coulomb antipairing effects on the systematic of the spontaneous fission half-lives for the nuclei $^{240-250}$Cm and $^{240-250}$Cf is analyzed, using a hierarchy of approximations based on the parametrization D1M of the Gogny energy density functional (EDF). First, the constrained Hartree-Fock-Bogoliubov (HFB) approximation is used to compute deformed mean-field configurations, zero-point quantum corrections and collective inertias either by using the Slater approximation to Coulomb exchange and neglecting Coulomb antipairing or by fully considering the exchange and pairing channels of the Coulomb interaction. Next, the properties of the {\it{least action}} and {\it{least energy}} fission paths are compared. In the {\it{least action}} case, pairing is identified as the relevant degree of freedom in order to minimize the action entering the Wentzel-Kramers-Brillouin (WKB) approximation to the tunneling probability through the fission barrier. Irrespective of the treatment of Coulomb exchange and antipairing, it is shown that the {\it{least action}} path obtained taking into account the pairing degree of freedom leads to stronger pairing correlations that significantly reduce the spontaneous fission half-lives $t_{SF}$ improving thereby the comparison with the experiment by several orders of magnitude. It is also shown that the Coulomb antipairing effect is, to a large extent, washed out by the {\it{least action}} procedure and therefore the $t_{SF}$ values obtained by the two different treatments of the Coulomb exchange and pairing are of similar quality.Comment: 13 pages, 8 figure

Thermal and phase transformations analysis in a PREMOMET® steel

Thermal analysis in a PREMOMET® steel has been performed by differential scanning calorimetry (DSC) and highresolution dilatometry. The phase transformation temperatures (Ac1, Ac3, Ms and Mf) of this steel were obtained by the two methods at different heating rates showing good agreement between both techniques. The enthalpy of α-γ transformation for this steel was measured using the thermograms acquired by DSC and microstructure was analyzed by scanning electron microscope (SEM). The results showed that this steel retained a martensitic structure for all conditions

Active galactic nuclei synapses: X-ray versus optical classifications using artificial neural networks

(Abridged) Many classes of active galactic nuclei (AGN) have been defined entirely throughout optical wavelengths while the X-ray spectra have been very useful to investigate their inner regions. However, optical and X-ray results show many discrepancies that have not been fully understood yet. The aim of this paper is to study the "synapses" between the X-ray and optical classifications. For the first time, the new EFLUXER task allowed us to analyse broad band X-ray spectra of emission line nuclei (ELN) without any prior spectral fitting using artificial neural networks (ANNs). Our sample comprises 162 XMM-Newton/pn spectra of 90 local ELN in the Palomar sample. It includes starbursts (SB), transition objects (T2), LINERs (L1.8 and L2), and Seyferts (S1, S1.8, and S2). The ANNs are 90% efficient at classifying the trained classes S1, S1.8, and SB. The S1 and S1.8 classes show a wide range of S1- and S1.8-like components. We suggest that this is related to a large degree of obscuration at X-rays. The S1, S1.8, S2, L1.8, L2/T2/SB-AGN (SB with indications of AGN), and SB classes have similar average X-ray spectra within each class, but these average spectra can be distinguished from class to class. The S2 (L1.8) class is linked to the S1.8 (S1) class with larger SB-like component than the S1.8 (S1) class. The L2, T2, and SB-AGN classes conform a class in the X-rays similar to the S2 class albeit with larger fractions of SB-like component. This SB-like component is the contribution of the star-formation in the host galaxy, which is large when the AGN is weak. An AGN-like component seems to be present in the vast majority of the ELN, attending to the non-negligible fraction of S1-like or S1.8-like component. This trained ANN could be used to infer optical properties from X-ray spectra in surveys like eRosita.Comment: 15 pages, 7 figures, accepted for publication in A&A. Appendix B only in the full version of the paper here: https://dl.dropboxusercontent.com/u/3484086/AGNSynapsis_OGM_online.pd

Current Therapeutic Options for the Main Monogenic Autoinflammatory Diseases and PFAPA Syndrome: Evidence-Based Approach and Proposal of a Practical Guide

Monogenic autoinflammatory diseases are rare conditions caused by genetic abnormalities affecting the innate immunity. Previous therapeutic strategies had been mainly based on results from retrospective studies and physicians' experience. However, during the last years, the significant improvement in their genetic and pathogenic knowledge has been accompanied by a remarkable progress in their management. The relatively recent identification of the inflammasome as the crucial pathogenic mechanism causing an aberrant production of interleukin 1β (IL-1β) in the most frequent monogenic autoinflammatory diseases led to the introduction of anti–IL-1 agents and other biologic drugs as part of the previously limited therapeutic armamentarium available. Advances in the treatment of autoinflammatory diseases have been favored by the use of new biologic agents and the performance of a notable number of randomized clinical trials exploring the efficacy and safety of these agents. Clinical trials have contributed to increase the level of evidence and provided more robust therapeutic recommendations. This review analyzes the treatment of the most frequent monogenic autoinflammatory diseases, namely, familial Mediterranean fever, tumor necrosis factor receptor–associated periodic fever syndrome, hyperimmunoglobulin D syndrome/mevalonate kinase deficiency, and cryopyrin-associated periodic syndromes, together with periodic fever with aphthous stomatitis, pharyngitis, and cervical adenitis syndrome, which is the most common polygenic autoinflammatory disease in children, also occurring in adult patients. Finally, based on the available expert consensus recommendations and the highest level of evidence of the published studies, a practical evidence-based guideline for the treatment of these autoinflammatory diseases is proposed

Tailoring the microstructure and tribological properties in commercially pure aluminium processed by High Pressure Torsion Extrusion

High Pressure Torsion Extrusion (HPTE) as a novel approach in mechanical nanostructuring of metallic materials and alloys has the potential to be utilized in industrial applications due to its unique features in fabricating bulk-nanostructured materials with enhanced mechanical and functional properties. Three different HPTE regimes based on the extrusion speed of the punch (v, mm/min) and rotational speed of the die (ω, rpm) were used in this work: v7w1, v1w1, and v1w3. The grain refinement obtained by this technique was outstanding since the initial grain size of 120 μm in annealed conditions was reduced to the final grain size of 0.7 μm in v1w3 in merely one pass of extrusion; however, each regime showed a different level of grain refinement depending on the imposed strain. Examination of the tribological properties by reciprocal wear testing in dry conditions revealed no significant change in the coefficient of friction; nevertheless, the mechanism of the wear from adhesion shifted to abrasion and the amount of displaced volume decreased. This modification is associated with the improvement of hardness and the reduction of plasticity in materials that confined the plastic shearing. Increasing the induced strain by changing the HPTE regimes decreased the overall displaced volume and reduced the built-up edge around the wear track

Low energy magnetic excitations of the Mn_{12}-acetate spin cluster observed by neutron scattering

We performed high resolution diffraction and inelastic neutron scattering measurements of Mn_{12}-acetate. Using a very high energy resolution, we could separate the energy levels corresponding to the splitting of the lowest S multiplet. Data were analyzed within a single spin model (S=10 ground state), using a spin Hamiltonian with parameters up to 4^{th} order. The non regular spacing of the transition energies unambiguously shows the presence of high order terms in the anisotropy (D= -0.457(2) cm^{-1}, B_4^0 = -2.33(4) 10^{-5}cm^{-1}). The relative intensity of the lowest energy peaks is very sensitive to the small transverse term, supposed to be mainly responsible for quantum tunneling. This allows an accurate determination of this term in zero magnetic field (B_4^4 = \pm 3.0(5) 10^{-5} cm^{-1}). The neutron results are discussed in view of recent experiments and theories.Comment: 4 pages ? 3 figures, submitted to Physical Review Lette