Description of nuclear systems with a self-consistent configuration-mixing approach. I: Theory, algorithm, and application to the 12^{12}C test nucleus

Although self-consistent multi-configuration methods have been used for decades to address the description of atomic and molecular many-body systems, only a few trials have been made in the context of nuclear structure. This work aims at the development of such an approach to describe in a unified way various types of correlations in nuclei, in a self-consistent manner where the mean-field is improved as correlations are introduced. The goal is to reconcile the usually set apart Shell-Model and Self-Consistent Mean-Field methods. This approach is referred as "variational multiparticle-multihole configuration mixing method". It is based on a double variational principle which yields a set of two coupled equations that determine at the same time the expansion coefficients of the many-body wave function and the single particle states. The formalism is derived and discussed in a general context, starting from a three-body Hamiltonian. Links to existing many-body techniques such as the formalism of Green's functions are established. First applications are done using the two-body D1S Gogny effective force. The numerical procedure is tested on the $^{12}$C nucleus in order to study the convergence features of the algorithm in different contexts. Ground state properties as well as single-particle quantities are analyzed, and the description of the first $2^+$ state is examined. This study allows to validate our numerical algorithm and leads to encouraging results. In order to test the method further, we will realize in the second article of this series, a systematic description of more nuclei and observables obtained by applying the newly-developed numerical procedure with the same Gogny force. As raised in the present work, applications of the variational multiparticle-multihole configuration mixing method will however ultimately require the use of an extended and more constrained Gogny force.Comment: 22 pages, 18 figures, accepted for publication in Phys. Rev. C. v2: minor corrections and references adde

Garden Theatre

Garden Theatre is a fifteen-minute piece for voices and chamber ensemble, which sets to music two poems by William Carlos Williams entitled Daisy and Queen Anne’s Lace. This piece is divided into two scenes (movements), each comprising three distinct sections. Garden Theatre will combine allusions to early music elements such as forms and methods of motivic development with a modern music aesthetic. In Garden Theatre there are four main pitch collections from which pitch material is derived. Continuity is promoted throughout the work by using many large and small-scale inter-referential elements such as recurring instrumental textures, pitch structures and thematic material. Garden Theatre also explores varying degrees of distinction between background and foreground. The utilization of a variety of vocal techniques and styles is a focal point of Garden Theatre

Impact of Beyond the Standard Model Physics in the Detection of the Cosmic Neutrino Background

We discuss the effect of Beyond the Standard Model charged current interactions on the detection of the Cosmic Neutrino Background by neutrino capture on tritium in a PTOLEMY-like detector. We show that the total capture rate can be substantially modified for Dirac neutrinos if scalar or tensor right-chiral currents, with strength consistent with current experimental bounds, are at play. We find that the total capture rate for Dirac neutrinos, $\Gamma_{\rm D}^{\rm BSM}$, can be between 0.3 to 2.2 of what is expected for Dirac neutrinos in the Standard Model, $\Gamma_{\rm D}^{\rm SM}$, so that it can be made as large as the rate expected for Majorana neutrinos with only Standard Model interactions. A non-negligible primordial abundance of right-handed neutrinos can only worsen the situation, increasing $\Gamma_{\rm D}^{\rm BSM}$ by 30 to 90\%. On the other hand, if a much lower total rate is measured than what is expected for $\Gamma_{\rm D}^{\rm SM}$, it may be a sign of new physics.Comment: Version published in JHEP. Some comments and references adde

A mathematical model quantifies proliferation and motility effects of TGF--β\beta on cancer cells

Transforming growth factor (TGF) $\beta$ is known to have properties of both a tumor suppressor and a tumor promoter. While it inhibits cell proliferation, it also increases cell motility and decreases cell--cell adhesion. Coupling mathematical modeling and experiments, we investigate the growth and motility of oncogene--expressing human mammary epithelial cells under exposure to TGF--$\beta$. We use a version of the well--known Fisher--Kolmogorov equation, and prescribe a procedure for its parametrization. We quantify the simultaneous effects of TGF--$\beta$ to increase the tendency of individual cells and cell clusters to move randomly and to decrease overall population growth. We demonstrate that in experiments with TGF--$\beta$ treated cells \textit{in vitro}, TGF--$\beta$ increases cell motility by a factor of 2 and decreases cell proliferation by a factor of 1/2 in comparison with untreated cells.Comment: 15 pages, 4 figures; to appear in Computational and Mathematical Methods in Medicin

A Minor Dihydropyran Apocarotenoid from Mated Cultures of Blakeslea trispora

The heterocyclic C15 apocarotenoid 1 was isolated from mated cultures of the strains F986 (+) and F921 (−) of Blakeslea trispora. This new compound formed during sexual interaction is a minor constituent of the culture media and its structure was elucidated by spectroscopic data, including 2D-NMR. A plausible biosynthetic pathway involving a double degradation of β-carotene, followed by several oxidations of the resulting monocyclofarnesane C15 fragment is proposed.This research was financed by Junta de Andalucía (Grants FQM 340, CVI 910, and P08-CVI-03901) and the Spanish Government (Grant CTQ 2010-16818, subprogram BQ)

Recycling of sludge from drinking water treatment as ceramic material for the manufacture of tiles

Currently, the main destination for sludge from Drinking Water Treatment Plants (DWTP) is its disposal in sanitary landfills. However, its chemical composition and physical properties make it suitable for use as a building material. In this work, the use of spray-dried DWTP sludge on the manufacture of cladding ceramic material for the production of tiles as an alternative to the final disposal of sludge is analysed. The work is based on an experimental study carried out on a laboratory scale. Clay and spray-dried DWTP sludge (average humidity of 3¿wt%) were mixed with different percentages of sludge (from 0 to 70¿wt%) to form a slurry to be extruded. Specimens were then fired up to 980¿°C. Chemical and mineralogical composition of raw materials was analysed. Technical properties of the ceramic samples were determined. The results obtained showed that the DWTP sludge became a powder with low organic content and a high-micronised calcareous content (14.4¿wt% calcium oxide). The ceramic samples had a high open porosity, which increases with the increase in sludge addition percentage. They also had a high dilatometric coefficient. Taking into account these two properties, a possible application of this material would be the manufacture of glazed tiles. The resulting ceramic material does not pose any environmental problem, far surpassing the NEN-7345 leaching test and accelerated degassing tests (outgassing PSS-01-702 and offgassing PSS-01-729 standards of the European Space Agency).Peer ReviewedPostprint (author's final draft