282 research outputs found
Bott periodicity and stable quantum classes
We use Bott periodicity to relate previously defined quantum classes to
certain "exotic Chern classes" on . This provides an interesting
computational and theoretical framework for some Gromov-Witten invariants
connected with cohomological field theories. This framework has applications to
study of higher dimensional, Hamiltonian rigidity aspects of Hofer geometry of
, one of which we discuss here.Comment: prepublication versio
Spherical Bondi accretion onto a magnetic dipole
Quasi-spherical supersonic (Bondi-type) accretion to a star with a dipole
magnetic field is investigated using resistive magnetohydrodynamic simulations.
A systematic study is made of accretion to a non-rotating star, while sample
results for a rotating star are also presented. A new stationary subsonic
accretion flow is found with a steady rate of accretion to the magnetized star
smaller than the Bondi accretion rate. Dependences of the accretion rate and
the flow pattern on the magnetic momentum of the star and the magnetic
diffusivity are presented. For slow star's rotation the accretion flow is
similar to that in non-rotating case, but in the case of fast rotation the
structure of the subsonic accretion flow is fundamentally different and
includes a region of ``propeller'' outflow. The methods and results described
here are of general interest and can be applied to systems where matter
accretes with low angular momentum.Comment: 15 pages, 15 figures, used emulapj.st
Calculations of the binding-energy differences for highly-charged Ho and Dy ions
The binding-energy differences for and
ions with ionization degrees , , and
are calculated. The calculations are performed using the large-scale
relativistic configuration-interaction and relativistic coupled-clusters
methods. The contributions from quantum-electrodynamics, nuclear-recoil, and
frequency-dependent Breit-interaction effects are taken into account. The final
uncertainty does not exceed eV. Combining the obtained results with the
binding-energy difference for neutral atoms calculated in [Savelyev et al.,
Phys. Rev. A 105, 012806 (2022)], we get the secondary differences of the
ion-atom binding energies. These values can be used to evaluate the amount of
energy released in the electron capture process in atom
(the value), provided mass differences of highly charged ions
and is known from experiment.
The value is required by experiments on the determination of the absolute
scale of the electron neutrino mass by studying the beta-decay process.Comment: 4 pages, Jetp Lett. (2023
Ground state of superheavy elements with : systematic study of the electron-correlation, Breit, and QED effects
For superheavy elements with atomic numbers , the concept
of the ground-state configuration is being reexamined. To this end,
relativistic calculations of the electronic structure of the low-lying levels
are carried out by means of the Dirac-Fock and configuration-interaction
methods.The magnetic and retardation parts of the Breit interaction as well as
the QED effects are taken into account. The influence of the relativistic, QED,
and electron-electron correlation effects on the determination of the
ground-state is analyzed
Calculation of sulfur removal in ladle furnace unit by means of ionic theory of slags
This article describes issues of sulfur removal in ladle furnace unit. First of all, metal desulfurization in ladle steel treatment units is achieved due to transition of sulfur to the slag phase. Coefficient of partition of sulfur between metal and slag is affected by sulfide capacity of slag, coefficient of activity of sulfur in the metal, oxidation potential of medium and reaction equilibrium constant of partition of sulfur between metal and slag. Temperature of liquid state in the ladle has significant impact on sulfide capacity of slag. Proposed calculation procedure based on provisions of ionic structure of slags allows evaluating a concentration of sulfur in steel on the basis of determination of coefficient of its partition between metal and slag. Optical basicity is suggested as criterion of refining property of slag, it has been shown that the amphoteric oxide Al2O3 is essential to calculation of this indicator. Its impact on sulfide capacity of slag is detected. © Published under licence by IOP Publishing Ltd
Sulfur partition by process stages of metallurgical production of JSC EVRAZ NTMK
The current level of development of the industry requires the manufacture of steel with high purity in relation to detrimental impurities. Sulfur is one of such impurities that significantly reduces the service properties, the content of which is strictly regulated in the finished product. Deep desulfurization may be achieved through development of cross-cutting technology of metal production as a single process including agglomeration and blast-furnace process and steelmaking. Sulfur partition by metallurgical process stages via conversion from raw materials of the blast-furnace process to steel continuously cast blank is studied in this work. It is shown that removal of sulfur from the half-finished product at the desulfurization plant will not provide the required sulfur content (less than 0.005 %) in the steel ingot. It is determined that the activity plan comprising treatment of the half-finished product at the desulfurization plant, smelting in the converter, treatment of steel at the ladle furnace unit and then in the vacuum vessel is required to obtain the final content of sulfur of less than 0.005%. © Published under licence by IOP Publishing Ltd
Comparative assessment of modern parameters of glycemic control in children with type 1 diabetes after switching to fast-acting insulin aspart using Flash Glucose Monitoring in real clinical practice
BACKGROUND: Postprandial hyperglycaemia contributes significantly to the lack of glycaemic control in patients with type 1 diabetes mellitus (DM1). At least a quarter of patients forget to inject insulin before meals once a week, and more than 40% of them inject bolus insulin immediately before meals, which does not correspond to the pharmacokinetic effects of ultrashort insulins and determines the need to use insulins with better imitations of physiological insulin secretion.AIM: To assess the effect of fast acting insulin aspart (FIAsp) on the current parameters of glycaemic control in children with DM1 after switching from insulin Asp (iAsp) using continuous glucose monitoring.MATERIALS AND METHODS: A multicenter observational 12-week prospective open-label uncontrolled comparative study was initiated. A group of insufficiently controlled patients were identified (n = 48) including a group on multiple insulin injections therapy (MII) (insulin degludec and IAsp) and a group on continuous subcutaneous insulin infusion (CSII) of iAsp. Three 14-day flash glucose monitoring (FMG) were performed: before transferring patients to FiAsp and after 2 and 12 weeks of the transfer. Key endpoints: HbA1c after 2 and 12 weeks on FiAsp relative to baseline, analysis of 5 FMG target glucose ranges, presented as an ambulatory glycemic profile. Additional indicators: dynamics of insulin daily dose, frequency of glucose self- monitoring, the number of severe hypoglycemia, adverse events that occurred during treatment.RESULTS: 2 weeks after the transfer from IAsp to FIAsp, TIR increased in the entire group of patients: from 53% [44.3; 66.5] to 57% [47.4; 71.0] (p-value = 0.010) and TAR decreased from 38% [24.8; 50.2] to 30.5% [22.0; 45, 0] (p-value = 0.0124). Maintaining and increase time spent in the target glucose ranges during a 12-week observation period, in parallel with a significant decrease in hypoglycemic episodes <3.9 mmol / L per week, on FIAsp therapy naturally leads to an improvement in diabetes control: a decrease in HbA1c from 8.15% up to 7.75% (p-value = 0.0224), more pronounced in the group of patients on CSII — from 7.9% to 7.5% (p-value = 0.028).CONCLUSION: Switching from IAsp to BDIAsp in routine clinical practice in the MII and CSII regimen in children and adolescents with type 1 diabetes allows achieving better glycemic control compared to the previous generation prandial insulin analog Iasp. The better diabetes control is associated with an increase or a trend towards an increase in TIR and a decrease or a trend towards a decrease in TAR and TBR, as well as a significant decrease in episodes of hypoglycemia
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