Optimized Effective Potential Method in Current-Spin Density Functional Theory

Current-spin density functional theory (CSDFT) provides a framework to describe interacting many-electron systems in a magnetic field which couples to both spin- and orbital-degrees of freedom. Unlike in usual (spin-) density functional theory, approximations to the exchange-correlation energy based on the model of the uniform electron gas face problems in practical applications. In this work, explicitly orbital-dependent functionals are used and a generalization of the Optimized Effective Potential (OEP) method to the CSDFT framework is presented. A simplifying approximation to the resulting integral equations for the exchange-correlation potentials is suggested. A detailed analysis of these equations is carried out for the case of open-shell atoms and numerical results are given using the exact-exchange energy functional. For zero external magnetic field, a small systematic lowering of the total energy for current-carrying states is observed due to the inclusion of the current in the Kohn-Sham scheme. For states without current, CSDFT results coincide with those of spin density functional theory.Comment: 11 pages, 3 figure

Scheduling aircraft’s engines repair process: a mathematical model

In this talk, we discuss a scheduling problem that originated at TAP - Maintenance & Engineering - the maintenance, repair and overhaul organization of Portugal’s leading airline. In the repair process of aircrafts’ engines, the operations to be scheduled may be executed on a certain workstation by any processor of a given set, and the objective is to minimize the total weighted tardiness. A mixed integer linear programming formulation, based on the flexible job shop scheduling, is presented here, along with computational experiment on a real instance, provided by TAP-ME, from a regular working week. The model was also tested using benchmarking instances available in literature

The generator coordinate method in time-dependent density-functional theory: memory made simple

The generator coordinate (GC) method is a variational approach to the quantum many-body problem in which interacting many-body wave functions are constructed as superpositions of (generally nonorthogonal) eigenstates of auxiliary Hamiltonians containing a deformation parameter. This paper presents a time-dependent extension of the GC method as a new approach to improve existing approximations of the exchange-correlation (XC) potential in time-dependent density-functional theory (TDDFT). The time-dependent GC method is shown to be a conceptually and computationally simple tool to build memory effects into any existing adiabatic XC potential. As an illustration, the method is applied to driven parametric oscillations of two interacting electrons in a harmonic potential (Hooke's atom). It is demonstrated that a proper choice of time-dependent generator coordinates in conjunction with the adiabatic local-density approximation reproduces the exact linear and nonlinear two-electron dynamics quite accurately, including features associated with double excitations that cannot be captured by TDDFT in the adiabatic approximation.Comment: 10 pages, 13 figure

Survival in COPD patients treated with bronchoscopic lung volume reduction

Background and objective: Severe COPD patients can significantly benefit from bronchoscopic lung volume reduction (BLVR) treatments with coils or endobronchial valves. However, the potential impact of BLVR on survival is less understood. Therefore, our aim was to investigate the survival rate in patients who are evaluated for BLVR treatment and whether there is a difference in survival rate between patients who undergo BLVR treatment and patients who do not. Methods: We included patients with COPD who visited our hospital for a consultation evaluating their eligibility for BLVR treatment and who performed pulmonary function tests during this visit. Furthermore, vital status was verified. Results: In total 1471 patients were included (63% female, mean age 61 years). A total of 531 patients (35%) died during follow-up and the median survival time of the total population was 2694 days (95% confidence interval(CI) 2462–2926) which is approximately 7.4 years. The median survival time of patients who were treated with BLVR was significantly longer compared to patients who were not treated with BLVR (3133 days versus 2503 days, p < 0.001), and BLVR was found to be an independent predictor of survival when adjusting for other survival-influencing factors such as age, gender or severity of disease. Conclusions: Our results suggest that bronchoscopically reducing lung volume in patients with severe hyperinflation may lead to a survival benefit for a population with a severely reduced life expectancy

NBS monograph

From Abstract: "This Monograph presents an outline of the methods used at the National Bureau of Standards to predict the performance of lenses from an analysis of their designs. The technique is based on the use of spot diagrams, which are analogs of star image tests, and makes extensive use of high-speed digital computers.

Density-functional calculation of ionization energies of current-carrying atomic states

Current-density-functional theory is used to calculate ionization energies of current-carrying atomic states. A perturbative approximation to full current-density-functional theory is implemented for the first time, and found to be numerically feasible. Different parametrizations for the current-dependence of the density functional are critically compared. Orbital currents in open-shell atoms turn out to produce a small shift in the ionization energies. We find that modern density functionals have reached an accuracy at which small current-related terms appearing in open-shell configurations are not negligible anymore compared to the remaining difference to experiment.Comment: 7 pages, 2 tables, accepted by Phys. Rev.

Rosette-forming glioneuronal tumor: a pineal region case with IDH1 and IDH2 mutation analyses and literature review of 43 cases

Rosette-forming glioneuronal tumor (RGNT) of the fourth ventricle is a mixed glio-neuronal neoplasm recently codified by the World Health Organization WHO Classification of Central Nervous System (CNS) Tumors (2007). To date, 43 cases have been described in the literature; most occurring in the fourth ventricle region. We report the fourth case involving the pineal region in a 16-year-old female with signs of increased intracranial pressure (ICP). A stereotactic biopsy of the mass was followed by a debulking procedure. Both specimens revealed classic RGNT histology. The patient had stable scans 7 months post-resection. The clinical, radiological and histopathologic features of the previously described 43 cases are reviewed along with our illustrative case. Mean age of patients was 30 ± 12.8 years with 1.9:1 female to male ratio. The most common presenting signs related to increased ICP and posterior fossa involvement, including: headache (62.8%), ataxia (39.5%) and vomiting and vertigo (both 16.3%). This tumor usually presents with cystic changes (54.5%) with focal enhancement (60.9%) and hydrocephalus (43.2%). Microcalcifications and satellite lesions were common radiographic observations. All reported cases had the classic biphasic pattern. Rosenthal fibers and eosinophilic granular bodies are each present in approximately two thirds of cases. Ki-67 labeling index is consistently low (mean (%): 1.8 ± 0.75 SD). The isocitrate dehydrogenase 1 or 2 mutation found in low grade diffuse gliomas is not identified in this RGNT case. Reported outcome is nearly uniformly excellent after complete or subtotal resection. A solitary report of recurrence after 10 years and the limited experience with this entity suggest that long term follow up is advisable

Simultaneous quantification of human herpesvirus 8 DNA by real time PCR in different tissues of HIV infected cuban patients with Kaposi's sarcoma

In Cuba, previous reports have shown an increase of epidemic KS, reaching a total of 120 cases by the end of 2007, despite the use of HAART. To evaluate and compare the role of human herpes virus 8 (HHV-8) viral loads in different compartments of AIDS-related Kaposi's sarcoma (AIDS-KS) patients real-time polymerase chain reaction (RT-PCR) was used to determine the genome copy number of HHV-8 in plasma, saliva, tissue and peripheral blood mononuclear cells (PBMC) of 49 AIDS-KS patients. Overall, 98% of AIDS-KS patients harbored detectable HHV-8. HHV-8 could be detected in 91.6% of KS tissue lesions showing the highest viral load (median log = 3.14 copies/100 ng DNA) followed by saliva and PBMC which were positive in 78%, and 69.2%; respectively. In contrast, HHV-8 was detected in only 37% of plasma samples, which also showed lower viral loads. Men who had sex with men (MSM) were more likely to have three-times higher HHV-8 genome copies in KS lesions when compared with tissues from heterosexuals individuals (OR 3; 95% CI 1.1 to 12.5). These results emphasize the systemic nature of HHV-8-infection and demonstrate the possible role of saliva in HHV-8 transmission among MSM

Intoxicaciones exógenas agudas, aspectos clínicos y epidemiológicos

A retrospective descriptive study was conducted with the aim of describing the clinical and epidemiological aspects in children and adolescents who were admitted with a diagnosis of acute exogenous poisoning to the José Luis Miranda Provincial Pediatric University Hospital in Santa Clara during 2006. The universe was made up of 400 patients. The sample was formed by 115 patients from Villa Clara province who were admitted with the diagnosis of accidental poisoning, iatrogenic poisoning or suicide. Variables such as age, sex, etiologic agent, cause of intoxication, and patient’s outcome were studied. These data were collected on a form, and were processed in the version 11 of the SPSS. Drug poisonings predominated, followed by suicide attempts. The evolution was satisfactory for most patients and minimal the consequences. There was no report of death in this study.Se realizó un estudio descriptivo retrospectivo con el objetivo de describir los aspectos clínicos y epidemiológicos en los niños y adolescentes con diagnóstico de intoxicaciones exógenas agudas que ingresaron en el Hospital Pediátrico Provincial Universitario “José Luis Miranda” de Santa Clara en el año 2006. El universo lo conformaron 400 pacientes, la muestra estuvo representada por 115 enfermos que ingresaron con el diagnóstico de intoxicación accidental, iatrogénica o suicida pertenecientes a la Provincia de Villa Clara. Se estudiaron variables como la edad, el sexo, el agente etiológico, la causa de la intoxicación y la evolución del paciente; todos estos datos se recogieron en un formulario y se procesaron en la  versión 11 del SPSS. Predominaron las intoxicaciones por medicamentos seguidas por los intentos suicidas, la evolución fue satisfactoria para la mayoría de los pacientes y las secuelas mínimas; no se informó ningún fallecido en este estudio