Numerically Precise Benchmark of Many-Body Self-Energies on Spherical Atoms.

We investigate the performance of beyond-GW approaches in many-body perturbation theory by addressing atoms described within the spherical approximation via a dedicated numerical treatment based on B-splines and spherical harmonics. We consider the GW, second Born (2B), and GW + second order screened exchange (GW+SOSEX) self-energies and use them to obtain ionization potentials from the quasi-particle equation (QPE) solved perturbatively on top of independent-particle calculations. We also solve the linearized Sham-Schlüter equation (LSSE) and compare the resulting xc potentials against exact data. We find that the LSSE provides consistent starting points for the QPE but does not present any practical advantage in the present context. Still, the features of the xc potentials obtained with it shed light on possible strategies for the inclusion of beyond-GW diagrams in the many-body self-energy. Our findings show that solving the QPE with the GW+SOSEX self-energy on top of a PBE or PBE0 solution is a viable scheme to go beyond GW in finite systems, even in the atomic limit. However, GW shows a comparable performance if one agrees to use a hybrid starting point. We also obtain promising results with the 2B self-energy on top of Hartree-Fock, suggesting that the full time-dependent Hartree-Fock vertex may be another viable beyond-GW scheme for finite systems.

Many-body perturbation theory calculations using the yambo code.

yambo is an open source project aimed at studying excited state properties of condensed matter systems from first principles using many-body methods. As input, yambo requires ground state electronic structure data as computed by density functional theory codes such as Quantum ESPRESSO and Abinit. yambo's capabilities include the calculation of linear response quantities (both independent-particle and including electron-hole interactions), quasi-particle corrections based on the GW formalism, optical absorption, and other spectroscopic quantities. Here we describe recent developments ranging from the inclusion of important but oft-neglected physical effects such as electron-phonon interactions to the implementation of a real-time propagation scheme for simulating linear and non-linear optical properties. Improvements to numerical algorithms and the user interface are outlined. Particular emphasis is given to the new and efficient parallel structure that makes it possible to exploit modern high performance computing architectures. Finally, we demonstrate the possibility to automate workflows by interfacing with the yambopy and AiiDA software tools.

Optoelectronic properties of natural cyanin dyes.

An integrated theoretical/experimental study of the natural cyanin dye is presented in terms of its structural and optoelectronic properties for different gas-phase and prototypical device configurations. Our microscopic analysis reveals the impact of hydration and hydroxylation reactions, as well as of the attached sugar, on ground and optically excited states, and it illustrates the visible-light harvesting capability of the dye. Our optical experiments at different and controlled pH concentrations allow for a direct comparison with theoretical results. We analyze the many different contributions to photocurrent of the various portions of a prototypical device and, as a proof of principle, we propose the addition of specific ligands to control the increase of the photocurrent yield in the cyanin-based electrochemical device.

Photoexcitation of a light-harvesting supramolecular triad: a time-dependent DFT study.

We present the first time-dependent density functional theory (TDDFT) calculation on a light-harvesting triad carotenoid-diaryl-porphyrin-C(60). Besides the numerical challenge that the ab initio study of the electronic structure of such a large system presents, we show that TDDFT is able to provide an accurate description of the excited-state properties of the system. In particular, we calculate the photoabsorption spectrum of the supramolecular assembly, and we provide an interpretation of the photoexcitation mechanism in terms of the properties of the component moieties. The spectrum is in good agreement with experimental data, and provides useful insight on the photoinduced charge-transfer mechanism which characterizes the system.

Ultrasonographic and computed tomographic diagnosis of benign masseteric hypertrophy.

Benign masseteric hypertrophy in a young child is presented. Diagnosis was confirmed by sonography and computed tomography. Recognition of this disorder obviates the need for further invasive investigations.

Severe dyspnea and dysphagia resulting from an aberrant cervical thymus.

A 5-month-old infant presented with severe dyspnea and dysphagia resulting from a right-sided cervical mass. At 5 months of age, a large aberrant thymus was excised, resulting in the disappearance of all symptoms. Pathological examination showed normal thymus tissue. Since the preoperative chest X-ray film showed a normal thymic shadow and the T-lymphocyte functions were normal, we conclude that this was not an ectopic gland but an undescended thymic implant.

Intestinal obstruction due to Ascaris lumbricoides mimicking intussusception.

Two children were admitted for clinical and radiologic signs of small-bowel obstruction. Examination revealed an abdominal mass that was suspected of being a mass of intussusception. Bowel obstruction caused by Ascaris lumbricoides was found at surgery. The laboratory, radiologic, and surgical findings are presented with a short review of the literature with emphasis on diagnosis, incidence, complications, and treatment.

Pseudo-precocious puberty in a young boy due to interstitial cell adenomas of the testis.

A case of pseudo-precocious puberty in a 2 4/12-year-old boy, due to Leydig cell adenomas of the testicle, is described. The special endocrine investigations revealed high levels of plasma testosterone and other androgens together with suppressed plasma gonadotropins unresponsive to stimulation. After operation the hormones returned to normal. The growth velocity and bone age were only gradually decreased, during a period of one year, while the sexual manifestations were the last to disappear, in the third year.

Intramural esophageal diverticulosis in an infant.

In the course of evaluating an infant with recurrent episodes of bronchiolitis, the esophagus was radiologically examined. A totally unexpected finding was the presence of intramural diverticulosis of the upper part of the esophagus. On reexamination four months later, the diverticula had disappeared.

A boy with 46, X, del, Y, due to a de nove mutation.

A newborn male referred for genetic investigation because of a large sized head and dysplastic ears, but with apparently normal male genitalia was found to have a deletion of all of the brightly fluorescent part of the long are of chromosome Y and absence of the Y fluorescent body on buccal smear. His father and his two brothers had normal Y chromosomes. Social and family history as well as marker investigation make illegitimacy most unlikely and leaves an occurrence of a new chromosomal mutation in the father the most probably interpretation. Follow-up of the infant to the age of 9 months revealed a large baby with normal development.