High--order connected moments expansion for the Rabi Hamiltonian

We analyze the convergence properties of the connected moments expansion (CMX) for the Rabi Hamiltonian. To this end we calculate the moments and connected moments of the Hamiltonian operator to a sufficiently large order. Our large--order results suggest that the CMX is not reliable for most practical purposes because the expansion exhibits considerable oscillations.Comment: 12 pages, 5 figures, 1 tabl

MAGNETIC PROPERTIES AND CRYSTAL STRUCTURE OF NONSTOICHIOMETRIC COMPOUNDS TbFe2MnX (0 ≤ X ≤ 0.4)

In this work, the magnetic properties and crystal structure of the TbFe2Mnx Laves phase were studied. It is shown that magnetic anisotropy constant Keff. decreases with increase of Mn content, while lattice constant increases.Работа выполнена при поддержке РФФИ (проект № 20-42-660008) и правительства Свердловской области

Towards crystal structure prediction of complex organic compounds - a report on the fifth blind test

Following on from the success of the previous crystal structure prediction blind tests (CSP1999, CSP2001, CSP2004 and CSP2007), a fifth such collaborative project (CSP2010) was organized at the Cambridge Crystallographic Data Centre. A range of methodologies was used by the participating groups in order to evaluate the ability of the current computational methods to predict the crystal structures of the six organic molecules chosen as targets for this blind test. The first four targets, two rigid molecules, one semi-flexible molecule and a 1: 1 salt, matched the criteria for the targets from CSP2007, while the last two targets belonged to two new challenging categories - a larger, much more flexible molecule and a hydrate with more than one polymorph. Each group submitted three predictions for each target it attempted. There was at least one successful prediction for each target, and two groups were able to successfully predict the structure of the large flexible molecule as their first place submission. The results show that while not as many groups successfully predicted the structures of the three smallest molecules as in CSP2007, there is now evidence that methodologies such as dispersion-corrected density functional theory (DFT-D) are able to reliably do so. The results also highlight the many challenges posed by more complex systems and show that there are still issues to be overcome

Organizational problems and possible ways of its resolve when providing emergency surgical care to patients with comorbid status in a highly specialized medical institution

Purpose of the study. To demonstrate the difficulties of objective interpretation of providing medical care to patients with critical limb ischemia.Materials and methods. The results of treatment of more than 29 thousand patients of one of the highly specialized medical organizations of St. Petersburg were studied, in which the main activity of the staff is the examination of patients with surgical infection of soft tissues (particularly, the critical limb ischemia).Results. It has been ascertained that, despite the unconditional success of providing medical care to patients with critical limb ischemia, a high frequency of unsatisfactory treatment results for this category of patients remains (in 2017, among 685 patients of the specialized department of the highly specialized medical organization, the proportion of cases of performing high amputations of limbs and mortality, respectively, was 11,7% (80) and 2,6% (18)). It has been demonstrated on clinical examples that the pronounced comorbidity of critical limb ischemia patients and the severity of their general condition (combined with organizational difficulties in providing them with providing medical care in conditions of highly specialized medical organization) contribute to the formation of complications (up to lethal outcomes) of not only the underlying, but also concomitant diseases. Difficulties in providing medical care of adequate quality in life-threatening conditions for patients of highly specialized medical organization in cases of critical limb ischemia necessitate a wider interaction between specialists in narrow and multidisciplinary hospitals as part of the emergency surgery service.Conclusion. When creating specialized medical centers outside of multidisciplinary medical institutions, the possibilities should be provided for the regulated involvement of highly professional consultants with a reasonable algorithm for routing patients in cases of the need for their emergency re-hospitalization to other medical institutions