32 research outputs found
Coupled tensorial form for atomic relativistic two-particle operator given in second quantization representation
General formulas of the two-electron operator representing either atomic or
effective interactions are given in a coupled tensorial form in relativistic
approximation. The alternatives of using uncoupled, coupled and antisymmetric
two-electron wave functions in constructing coupled tensorial form of the
operator are studied. The second quantization technique is used. The considered
operator acts in the space of states of open-subshell atoms
QED Calculation of E1M1 and E1E2 Transition Probabilities in One-Electron Ions with Arbitrary Nuclear Charge
The quantum electrodynamical theory of the two-photon transitions in
hydrogenlike ions is presented. The emission probability for 2s1/2 -> 2E1+1s1/2
transitions is calculated and compared to the results of the previous
calculations. The emission probabilities 2p12 -> E1E2+1s1/2 and 2p1/2 ->
E1M1+1s1/2 are also calculated for the nuclear charge Z values 1-100. This is
the first calculation of the two latter probabilities. The results are given in
two different gauges.Comment: 14 pages, 4 tables, 1 figur
Endovascular therapy for advanced post-thrombotic syndrome: Proceedings from a multidisciplinary consensus panel
Patients with advanced post-thrombotic syndrome (PTS) and chronic iliac vein obstruction suffer major physical limitations and impairment of health-related quality of life. Currently there is a lack of evidence-based treatment options for these patients. Early studies suggest that imaging-guided, catheter-based endovascular therapy can eliminate iliac vein obstruction and saphenous venous valvular reflux, resulting in reduced PTS severity; however, these observations have not been rigorously validated. A multidisciplinary expert panel meeting was convened to plan a multicenter randomized controlled clinical trial to evaluate endovascular therapy for the treatment of advanced PTS. This article summarizes the findings of the panel, and is expected to assist in developing a National Institutes of Health-sponsored clinical trial and other studies to improve the care of patients with advanced PTS
Dirac electrons in graphene-based quantum wires and quantum dots
In this paper we analyse the electronic properties of Dirac electrons in
finite-size ribbons and in circular and hexagonal quantum dots made of
graphene.Comment: Contribution for J. Phys.: Cond. Mat. special issue on graphene
physic
Early infant HIV-1 diagnosis programs in resource-limited settings: opportunities for improved outcomes and more cost-effective interventions
Early infant diagnosis (EID) of HIV-1 infection confers substantial benefits to HIV-infected and HIV-uninfected infants, to their families, and to programs providing prevention of mother-to-child transmission (PMTCT) services, but has been challenging to implement in resource-limited settings. In order to correctly inform parents/caregivers of infant infection status and link HIV-infected infants to care and treatment, a 'cascade' of events must successfully occur. A frequently cited barrier to expansion of EID programs is the cost of the required laboratory assays. However, substantial implementation barriers, as well as personnel and infrastructure requirements, exist at each step in the cascade. In this update, we review challenges to uptake at each step in the EID cascade, highlighting that even with the highest reported levels of uptake, nearly half of HIV-infected infants may not complete the cascade successfully. We next synthesize the available literature about the costs and cost effectiveness of EID programs; identify areas for future research; and place these findings within the context of the benefits and challenges to EID implementation in resource-limited settings
Relativistic quantum mechanical calculations of electron-impact broadening for spectral lines in Be-like ions
Aims. We present relativistic quantum mechanical calculations of electron-impact broadening of the singlet and triplet transition 2s3s <- 2s3p in four Be-like ions from N IV to Ne VII. Methods. In our theoretical calculations, the K-matrix and related symmetry information determined by the colliding systems are generated by the DARC codes. Results. A careful comparison between our calculations and experimental results shows good agreement. Our calculated widths of spectral lines also agree with earlier theoretical results. Our investigations provide new methods of calculating electron-impact broadening parameters for plasma diagnostics.Astronomy & AstrophysicsSCI(E)EI2ARTICLEnull54
Endovascular therapy for advanced post-thrombotic syndrome: Proceedings from a multidisciplinary consensus panel
Patients with advanced post-thrombotic syndrome (PTS) and chronic iliac vein obstruction suffer major physical limitations and impairment of health-related quality of life. Currently there is a lack of evidence-based treatment options for these patients. Early studies suggest that imaging-guided, catheter-based endovascular therapy can eliminate iliac vein obstruction and saphenous venous valvular reflux, resulting in reduced PTS severity; however, these observations have not been rigorously validated. A multidisciplinary expert panel meeting was convened to plan a multicenter randomized controlled clinical trial to evaluate endovascular therapy for the treatment of advanced PTS. This article summarizes the findings of the panel, and is expected to assist in developing a National Institutes of Health-sponsored clinical trial and other studies to improve the care of patients with advanced PTS