Giant Monopole Resonances and nuclear incompressibilities studied for the zero-range and separable pairing interactions

Background: Following the 2007 precise measurements of monopole strengths in tin isotopes, there has been a continuous theoretical effort to obtain a precise description of the experimental results. Up to now, there is no satisfactory explanation of why the tin nuclei appear to be significantly softer than 208Pb. Purpose: We determine the influence of finite-range and separable pairing interactions on monopole strength functions in semi-magic nuclei. Methods: We employ self-consistently the Quasiparticle Random Phase Approximation on top of spherical Hartree-Fock-Bogolyubov solutions. We use the Arnoldi method to solve the linear-response problem with pairing. Results: We found that the difference between centroids of Giant Monopole Resonances measured in lead and tin (about 1 MeV) always turns out to be overestimated by about 100%. We also found that the volume incompressibility, obtained by adjusting the liquid-drop expression to microscopic results, is significantly larger than the infinite-matter incompressibility. Conclusions: The zero-range and separable pairing forces cannot induce modifications of monopole strength functions in tin to match experimental data.Comment: 11 RevTeX pages, 16 figures, 1 table, extended versio

Increasing silicon concentrations in Bohemian Forest lakes

International audienceLong-term trends of dissolved silicon (Si) concentrations in five glacial lakes in the Bohemian Forest, Czech Republic, recovering from acidification show higher mobility of Si from the soil to surface waters despite lower atmospheric deposition of acids. Si increased by 0.95 to 1.95 µmol yr-1 (36 to 51%) from 1986-2004 and with increasing pH. A change in soil solution conditions because of a sharp decrease in acidic deposition has led to marked decline in Al mobility and to considerable decreases in dissolved Al, especially Al3+. The increase in Si may be related to: (1) unblocking of the inhibitory effect of dissolved Al on weathering of aluminosilicates, (2) biogenic opal (phytoliths) dissolving faster, and/or (3) lower Si precipitation as secondary aluminosilicates in soil. The change in Al speciation on the dissolution rate of biogenic silica is critical. A lack of change in Si at sites outside central Europe may be explained by small or no decline in mobility of dissolved Al. The effect of a long-term increase in temperature was probably minor

Self-consistent studies of the dipole response in neutron rich nuclei using realistic potentials

The dipole response in neutron rich nuclei is investigated within self-consistent approaches which make direct use of a nucleon-nucleon optimized chiral potential complemented with a density dependent term simulating a three-body force. Hartree-Fock-Bogoliubov plus Tamm-Dancoff and random-phase approximations show that such a potential improves the description of the dipole modes with respect to other realistic interactions. The inclusion of the two-phonon states within an equation of motion method induces a pronounced fragmentation of both giant and pygmy resonances in agreement with recent experiments

Nuclear Spectroscopic Properties within a Selfconsistent Multiphonon Approach

The equation of motion phonon method is adopted to investigate the dipole response in neutron rich nuclei. The calculation is carried out in a space spanned by one- and two-phonon basis states. It makes direct use of a nucleon-nucleon optimized chiral potential complemented with a density dependent term simulating a three-body force and is fully selfconsistent. The inclusion of the two-phonon states induces a pronounced fragmentation of both giant and pygmy resonances consistently with recent experiments

Selfconsistent mean field calculations of the nuclear response using a realistic nucleon-nucleon interaction with a density dependent corrective term

Tamm-Dancoff and random-phase approximations are formulated in the canonical Hartree-Fock-Bogoliubov quasi-particle basis and adopted to compute the E1 response in Ca isotopes using an intrinsic Hamiltonian composed of a Vlowk potential, deduced from the CD-Bonn nucleon-nucleon interaction, corrected with phenomenological density dependent and spin-orbit terms. Attention is focused on the evolution of the dipole strength distribution, including the low-lying transitions associated to the pygmy resonance, in going from the N = Z 40Ca to Ca isotopes with neutron excess

Coupling computer-interpretable guidelines with a drug-database through a web-based system – The PRESGUID project

BACKGROUND: Clinical Practice Guidelines (CPGs) available today are not extensively used due to lack of proper integration into clinical settings, knowledge-related information resources, and lack of decision support at the point of care in a particular clinical context. OBJECTIVE: The PRESGUID project (PREScription and GUIDelines) aims to improve the assistance provided by guidelines. The project proposes an online service enabling physicians to consult computerized CPGs linked to drug databases for easier integration into the healthcare process. METHODS: Computable CPGs are structured as decision trees and coded in XML format. Recommendations related to drug classes are tagged with ATC codes. We use a mapping module to enhance computerized guidelines coupling with a drug database, which contains detailed information about each usable specific medication. In this way, therapeutic recommendations are backed up with current and up-to-date information from the database. RESULTS: Two authoritative CPGs, originally diffused as static textual documents, have been implemented to validate the computerization process and to illustrate the usefulness of the resulting automated CPGs and their coupling with a drug database. We discuss the advantages of this approach for practitioners and the implications for both guideline developers and drug database providers. Other CPGs will be implemented and evaluated in real conditions by clinicians working in different health institutions

Predators and parasitoids of the harlequin ladybird, Harmonia axyridis, in its native range and invaded areas

The harlequin ladybird Harmonia axyridis (Coleoptera: Coccinellidae) has rapidly spread in several continents over the past 30 years and is considered an invasive alien species. The success of H. axyridis as an invader is often attributed to weak control by natural enemies. In this paper, we provide an overview of current knowledge on predators and parasitoids of H. axyridis. The common feature of predators and parasitoids is that they directly kill exploited organisms. Currently available data show that H. axyridis, displaying a variety of chemical, mechanical, and microbiological anti-predator defenses, is usually avoided by predators. However, some birds and invertebrates can eat this ladybird without harmful consequences. The primary defenses of H. axyridis against parasitoids include immune response and physiological and nutritional unsuitability for parasitoid development. These defenses are probably relatively efficient against most ladybird parasitoids, but not against flies of the genus Phalacrotophora. The latter are idiobiont parasitoids and hence can evade the host’s immune response. Indeed, rates of parasitism of H. axyridis by Phalacrotophora in the Palaearctic region (both in the native range in Asia and in Europe) are relatively high. While strong evidence for enemy release on the invasive populations of H. axyridis is lacking, several cases of parasitoid acquisition have been recorded in Europe, North America, and South America. We conclude that enemy release cannot be excluded as a possible mechanism contributing to the spread and increase of H. axyridis in the early stages of invasion, but adaptation of parasitoids may lead to novel associations which might offset previous effects of enemy release. However, further work is required to elucidate the population-level effects of such interactions