Schwinger particle production: rapid switch off of the external field versus dynamical assistance

We consider the process of electron-positron pair production in the presence of strong electric backgrounds being rapidly switched on and off and examine the total particle yield. For sufficiently sharp field profiles, the particle number can be substantially enhanced. It is demonstrated that this enhancement is quite similar to the phenomenon of dynamical assistance by a weak high-frequency field superimposed on a strong background. Both these mechanisms are analyzed by means of exact numerical computations and the locally-constant field approximation. We identify the time scale of the switching profile leading to the pair-production enhancement and argue that the particle yield is highly unlikely to be increased by shaping the switch off of realistic laser pulses. On the other hand, we confirm that it is feasible to observe the dynamically assisted Schwinger effect by adding a rapidly oscillating field to a strong electric background.Comment: 9 pages, 5 figures, 1 tabl

Multiplicative slices, relativistic Toda and shifted quantum affine algebras

We introduce the shifted quantum affine algebras. They map homomorphically into the quantized $K$-theoretic Coulomb branches of $3d\ {\mathcal N}=4$ SUSY quiver gauge theories. In type $A$, they are endowed with a coproduct, and they act on the equivariant $K$-theory of parabolic Laumon spaces. In type $A_1$, they are closely related to the open relativistic quantum Toda lattice of type $A$.Comment: 125 pages. v2: references updated; in section 11 the third local Lax matrix is introduced. v3: references updated. v4=v5: 131 pages, minor corrections, table of contents added, Conjecture 10.25 is now replaced by Theorem 10.25 (whose proof is based on the shuffle approach and is presented in a new Appendix). v6: Final version as published, references updated, footnote 4 adde

Fermionic formulas for eigenfunctions of the difference Toda Hamiltonian

We use the Whittaker vectors and the Drinfeld Casimir element to show that eigenfunctions of the difference Toda Hamiltonian can be expressed via fermionic formulas. Motivated by the combinatorics of the fermionic formulas we use the representation theory of the quantum groups to prove a number of identities for the coefficients of the eigenfunctions.Comment: 33 pages, Late

The classical R-matrix of AdS/CFT and its Lie dialgebra structure

The classical integrable structure of Z_4-graded supercoset sigma-models, arising in the AdS/CFT correspondence, is formulated within the R-matrix approach. The central object in this construction is the standard R-matrix of the Z_4-twisted loop algebra. However, in order to correctly describe the Lax matrix within this formalism, the standard inner product on this twisted loop algebra requires a further twist induced by the Zhukovsky map, which also plays a key role in the AdS/CFT correspondence. The non-ultralocality of the sigma-model can be understood as stemming from this latter twist since it leads to a non skew-symmetric R-matrix.Comment: 22 pages, 2 figure

Комплексное использование перфузионных технологий при трансплантации почек от донора с внегоспитальной остановкой кровообращения (клинический случай)

Objective: to present the successful experience with a donor with out-of-hospital cardiac arrest (OHCA) in whom a set of modern perfusion techniques was used to obtain kidneys suitable for transplantation.Materials and methods. Automatic chest compression was resumed in an OHCA donor (after biological death has been confirmed in the hospital) to maintain minimal perfusion under mechanical ventilation with 100% FiO2. With femoral vein cannulation, an extracorporeal circuit with a centrifuge pump and oxygenator was connected and abdominal normothermic regional perfusion was initiated. After 215 minutes, kidney was explanted under normothermic machine perfusion. Next, the left kidney was placed in the LifePort Kidney Transporter for hypothermic machine perfusion of donor kidneys. Perfusion time was 285 minutes. The right kidney was transplanted without additional ex-vivo perfusion.Results. Due to the complex use of perfusion techniques both in the donor body and ex-vivo, donor kidneys, after OHCA, with a total warm ischemia time of 110 minutes, were transplanted to recipients with good results. In the postoperative period, there was delayed function of the left and right renal grafts. The patients were discharged in a satisfactory condition under outpatient follow-up.Conclusion. The possibility and efficiency of organ donation after OHCA, facilitated by modern perfusion techniques and devices, open up a new perspective in addressing the organ shortage crisis.Цель: представить успешный опыт работы с донором с внегоспитальной остановкой кровообращения, у которого использовался комплекс современных перфузионных технологий, направленных на получение почек, пригодных для трансплантации.Материалы и методы. У донора с внегоспитальной остановкой кровообращения после констатации биологической смерти в стационаре возобновлена автоматическая компрессия грудной клетки для поддержания минимальной перфузии в условиях искусственной вентиляции легких c FiO2 100%. Путем канюляции бедренных сосудов подключен экстракорпоральный контур с центрифужным насосом и оксигенатором и начата нормотермическая перфузия абдоминальных органов. По истечении 215 минут в условиях нормотермической перфузии выполнена эксплантация почек. Далее левая почка помещена в устройство для гипотермической перфузии донорских почек LifePort, время перфузии составило 285 минут. Правая почка пересажена без дополнительной перфузии ex vivo. Результаты. Благодаря комплексному использованию перфузионных технологий как в организме донора, так и ex vivo почки донора после внегоспитальной остановки кровообращения с общим временем тепловой ишемии 110 минут были пересажены реципиентам с хорошими результатами. В послеоперационном периоде отмечалась отсроченная функция левого и правого почечного трансплантатов. Пациенты выписаны в удовлетворительном состоянии под амбулаторное наблюдение.Заключение. Возможность и эффективность донорства органов после внегоспитальной остановки кровообращения, обеспечиваемого современными перфузионными технологиями и устройствами, открывает новую перспективу в решении дефицита донорских органов для трансплантации.

Разработка искусственных почвогрунтов в смеси с различными местными агрорудами, мелиорантами, отходами сельскохозяйственного и промышленного производства

In the process of growth and development, cultivated plants synthesize dry matter by removing mineral nutrients from the soil. Therefore, the root layer of cultivated plants must be rich in elements of mineral nutrition. Their economic removal as a result of alienation from the grown crop requires a return to the soil to increase its fertility and ensure the productivity of the upcoming harvest. The research aims to develop artificial grounds mixed with various local agricultural ores, ameliorants, and waste from agricultural and industrial production, including macro- and microelements. Studies were conducted under artificial conditions in the phytotron of Bashkir State Agrarian University. In the control variant, oats had the highest productivity and plant survival (57.0%), slightly lower - in spring wheat (43.0%), and the lowest - in pea (28.0%) because of potting soil acidity. The authors believe that the addition of zeolite to the soil increases the productivity of peas by 20.0%; spring wheat by 20.9; oats by 24.0%; with phosphogypsum by 38.0, 24.9 and 30.0%, respectively. The most effective in the experiments was the variant of potting soils with defecate. The growth in pea plants was 44.0%, spring wheat - 29.10 and oats - 234.0%. Potting soils and their components have excellent prospects in crop production in Russia.В процессе роста и развития культурные растения синтезируют сухое вещество с выносом элементов минерального питания из почвы. Поэтому корнеобитаемый слой культурных растений должен быть богат элементами минерального питания, а хозяйственный вынос их в результате отчуждения с выращенным урожаем требует возвращения обратно в почву в целях повышения ее плодородия и обеспечения продуктивности предстоящей культуры. Целью исследований является разработка искусственных почвогрунтов в смеси с различными местными агрорудами, мелиорантами и отходами сельскохозяйственного и промышленного производства, включающими макро- и микроэлементы. Исследования проводились в искусственных условиях в фитотроне БГАУ. В контрольном варианте из-за кислотности почвогрунта наибольшая продуктивность и выживаемость растений отмечена у овса (57,0%), несколько меньшая – у яровой пшеницы (43,0%) и наименьшая – у гороха (28,0%). Добавление цеолита в почвогрунт обеспечило повышение продуктивности гороха на 20,0%, яровой пшеницы – на 20,9, овса – на 24,0%; с фосфогипсом соответственно на 38,0; 24,9 и 30,0%. Самым эффективным в опытах был вариант почвогрунта с дефекатом. Прирост у растений гороха составил 44,0%, яровой пшеницы – 29,10 и овса – 234,0%. Почвогрунты и их компоненты имеют большую перспективу в производстве продукции растениеводства в России

Raman spectra of single-walled carbon nanotubes synthesized by aerosol CVD-method using ferrocene and CuNi nanoparticles

Properties of single-walled carbon nanotubes (SWCNTs) obtained by aerosol method of chemical deposition from the gas phase using ethanol, ferrocene, and CuNi nanoparticles are studied. The structural and vibrational characteristics of synthesis products are determined by Raman spectroscopy. The influence of the catalyst nanoparticles introduced into the reaction mixture on the properties of the synthesized SWCNTs is discussed

Raman spectra of single-walled carbon nanotubes synthesized by aerosol CVD-method using ferrocene and CuNi nanoparticles

Properties of single-walled carbon nanotubes (SWCNTs) obtained by aerosol method of chemical deposition from the gas phase using ethanol, ferrocene, and CuNi nanoparticles are studied. The structural and vibrational characteristics of synthesis products are determined by Raman spectroscopy. The influence of the catalyst nanoparticles introduced into the reaction mixture on the properties of the synthesized SWCNTs is discussed