Two-proton radioactivity and three-body decay. V. Improved momentum distributions

Nowadays quantum-mechanical theory allows one to reliably calculate the processes of 2p radioactivity (true three-body decays) and the corresponding energy and angular correlations up to distances of the order of 1000 fm. However, the precision of modern experiments has now become sufficient to indicate some deficiency of the predicted theoretical distributions. In this paper we discuss the extrapolation along the classical trajectories as a method to improve the convergence of the theoretical energy and angular correlations at very large distances (of the order of atomic distances), where only the long-range Coulomb forces are still operating. The precision of this approach is demonstrated using the "exactly" solvable semianalytical models with simplified three-body Hamiltonians. It is also demonstrated that for heavy 2p emitters, the 2p decay momentum distributions can be sensitive to the effect of the screening by atomic electrons. We compare theoretical results with available experimental data.Comment: 13 pages, 18 figure

Spatial beam self-cleaning and supercontinuum generation with Yb-doped multimode graded-index fiber taper based on accelerating self-imaging and dissipative landscape

We experimentally demonstrate spatial beam self-cleaning and supercontinuum generation in a tapered Ytterbium-doped multimode optical fiber with parabolic core refractive index profile when 1064 nm pulsed beams propagate from wider (122 µm) into smaller (37 µm) diameter. In the passive mode, increasing the input beam peak power above 20 kW leads to a bell-shaped output beam profile. In the active configuration, gain from the pump laser diode permits to combine beam self-cleaning with supercontinuum generation between 520-2600 nm. By taper cut-back, we observed that the dissipative landscape, i.e., a non-monotonic variation of the average beam power along the MMF, leads to modal transitions of self-cleaned beams along the taper length

Dependence of the Energy Spectrum of UHE Cosmic Rays on the Latitude of an Extensive Air Shower Array

Several energy spectra of cosmic rays with energies E_0 \geq 10^17 eV measured at the Yakutsk EAS, AGASA, Haverah Park, HiRes, Auger, and SUGAR arrays are considered. It is shown that the fairly good mutual agreement of the spectrum shapes can be achieved if the energy of each spectrum is multiplied by a factor K specific for each spectrum. These factors exhibit a pronounced dependence on the latitude of the above-mentioned arrays.Comment: 4 pages, 4 figure

Failing systemic right ventricle in a patient with dextrocardia and complex congenitally corrected transposition of the great arteries: a case report of successful transvenous cardiac resynchronization therapy

Background Patients with congenitally corrected transposition of the great arteries (ccTGA) are prone to the development of advanced atrio-ventricular block requiring chronic ventricular pacing. The morphological right ventricle (RV) often develops systolic dysfunction as it is unable to withstand the chronic pressure overload it is exposed to when supporting the systemic circulation.Case summary A 56-year-old woman with dextrocardia and complex ccTGA with a history of dual-chamber implantable cardioverter-defibrillator (DDD-ICD, high degree atrio-ventricular-block and syncopal ventricular tachycardia), presented with progressive heart failure and symptomatic atrial arrhythmias. She underwent a successful ablation and concomitant invasive haemodynamic evaluation of potential alternative/biventricular pacing modalities. During biventricular pacing, the QRS narrowed and the systemic RV intraventricular pressure (Dp/Dt) increased with 30%. She underwent a successful transvenous upgrade to cardiac resynchronization therapy (CRT). The electrocardiogram post-implantation showed biventricular capture and patient showed subjective and objective clinical improvement.Discussion Systemic RV dysfunction in ccTGA can be aggravated by chronic pacing-induced dyssynchrony, contributing to progression of heart failure in this patient group. Transvenous CRT is feasible in ccTGA anatomy and may be pursued in order to improve or preserve the functional status of pacing-dependent ccTGA patients. Invasive haemodynamic contractility evaluation can help assess the potential benefit of CRT in patients with complex anatomy.Cardiolog

The observation of long-range three-body Coloumb effects in the decay of 16Ne

The interaction of an $E/A$=57.6-MeV $^{17}$Ne beam with a Be target was used to populate levels in $^{16}$Ne following neutron knockout reactions. The decay of $^{16}$Ne states into the three-body $^{14}$O+$p$+$p$ continuum was observed in the High Resolution Array (HiRA). For the first time for a 2p emitter, correlations between the momenta of the three decay products were measured with sufficient resolution and statistics to allow for an unambiguous demonstration of their dependence on the long-range nature of the Coulomb interaction. Contrary to previous experiments, the intrinsic decay width of the $^{16}$Ne ground state was found to be narrow ($\Gamma<60$~keV), consistent with theoretical estimates.Comment: 6 pages, 5 figure

Outcomes of endovascular treatment of ruptured abdominal aortic aneurysms

IntroductionThe successful application of endovascular techniques for the elective repair of abdominal aortic aneurysms (AAAs) has stimulated a strong interest in their possible use in dealing with a long-standing surgical challenge: the ruptured abdominal aortic aneurysm (RAAA). The use of a conventional open procedure to repair ruptured aneurysms is associated with a high operative mortality of 45% to 50%. In this study, we evaluated the current frequency of endovascular repair of RAAAs in four large states and the impact of this technique on patient outcome.MethodsWe examined discharge data sets from 2000 through 2003 from the four states of California, Florida, New Jersey, and New York, whose combined population represents almost a third of the United States population. Proportions and trends were analyzed by χ2 analysis and continuous variables by the Student’s t test.ResultsWe found that since the year 2000, endovascular repair has begun to emerge as a viable treatment option for RAAAs, accounting for the repair of 6.2% of cases in 2003. During the same period, the use of open procedures for RAAAs declined. The overall mortality rate for the 4-year period was significantly lower for endovascular vs open repair (39.3% vs. 47.7%, P = .005). Moreover, compared with open repair, endovascular repair resulted in a significantly lower rate of pulmonary, renal, and bleeding complications. Survival after endovascular repair correlated with hospital experience, as assessed by the overall volume of elective and nonelective endovascular procedures. For endovascular repairs, mortality ranged from 45.9% for small volume hospitals to 26% for large volume hospitals (P = .0011). Volume was also a determinant of mortality for open repairs, albeit to a much lesser extent (51.5% for small volume hospitals, 44.3% for large volume hospitals; P < .0001).ConclusionWe observed a benefit to using endovascular procedures for RAAAs in institutions with significant endovascular experience; however, the analysis of administrative data cannot rule out selection bias as an explanation of better outcomes. These data strongly endorse the need for prospective studies to clarify to what extent the improved survival in RAAA patients is to be attributed to the endovascular approach rather than the selection of low-risk patients

Взаимозависимость природоохранной деятельности и инвестиционной привлекательности: финансы российской металлургии

All countries now share a long-term vision of the importance of implementing technology development and transfer to improve climate resilience and reduce greenhouse gas emissions. Metallurgical enterprises play a significant role in achieving this goal, since they produce a large amount of carbon dioxide emissions into the atmosphere. In connection with the changing operating conditions and changing markets of presence, the issues of ensuring their investment attractiveness are acquiring obvious importance in the framework of the finances of Russian metallurgical companies. The object of the study is an assessment of the investment attractiveness of Russian metallurgical companies. The subject of the study is the relationship between the investment attractiveness of metallurgical companies and the results of their environmental protection activities. The purpose of this study is to identify the interdependence of environmental metrics and the investment attractiveness of steel companies. The methodological basis is a regression analysis of the impact of environmental metrics on the investment attractiveness of metallurgical companies. The authors chose the following indicators of environmental performance: CO2 emissions, energy consumption, water recycling, waste. To assess the investment attractiveness of metallurgical companies, the following indicators were used: revenue, EBITDA, investment in R&amp;D. The authors concluded that the environmental activities of companies have a significant impact on their investment attractiveness. The scientific novelty of the study lies in identifying the interdependence of environmental protection activities and the investment attractiveness of Russian metallurgy companies. The results of the study can be used by both Russian steel companies and institutional investors as part of the development of an investment strategy.В настоящее время все страны разделяют долгосрочное видение важности реализации разработки и передачи технологий для повышения устойчивости к изменению климата и сокращения выбросов парниковых газов. Значительную роль в достижении этой цели играют предприятия металлургической отрасли, поскольку они являются производителями большого количества выбросов углекислого газа в атмосферу. В связи с меняющимися условиями функционирования и сменой рынков присутствия очевидную важность в рамках финансов российских металлургических компаний приобретают вопросы обеспечения их инвестиционной привлекательности. Объектом исследования является оценка инвестиционной привлекательности российских металлургических компаний. Предмет изучения — связь между инвестиционной привлекательностью металлургических компаний и результатами проводимой ими природоохранной деятельности. Целью данного исследования является выявление взаимозависимости экологических метрик и инвестиционной привлекательности металлургических компаний. Методологическую основу составляет регрессионный анализ влияния экологических метрик на инвестиционную привлекательность металлургических компаний. Авторы выбрали следующие показатели экологической деятельности: выбросы CO2 , потребление энергии, вторичное использование воды, отходы. Для оценки инвестиционной привлекательности металлургических компаний использовались следующие показатели: выручка, EBITDA, инвестиции в НИОКР. Авторами сделан вывод о существенном влиянии экологической деятельности компаний на их инвестиционную привлекательность. Научная новизна исследования заключается в выявлении взаимозависимости природоохранной деятельности и инвестиционной привлекательности компаний российской металлургии, результаты исследования могут быть использованы как российскими металлургическими компаниями, так и институциональными инвесторами в рамках разработки инвестиционной стратегии

Real-time observation of multiexcitonic states in ultrafast singlet fission using coherent 2D electronic spectroscopy.

Singlet fission is the spin-allowed conversion of a spin-singlet exciton into a pair of spin-triplet excitons residing on neighbouring molecules. To rationalize this phenomenon, a multiexcitonic spin-zero triplet-pair state has been hypothesized as an intermediate in singlet fission. However, the nature of the intermediate states and the underlying mechanism of ultrafast fission have not been elucidated experimentally. Here, we study a series of pentacene derivatives using ultrafast two-dimensional electronic spectroscopy and unravel the origin of the states involved in fission. Our data reveal the crucial role of vibrational degrees of freedom coupled to electronic excitations that facilitate the mixing of multiexcitonic states with singlet excitons. The resulting manifold of vibronic states drives sub-100 fs fission with unity efficiency. Our results provide a framework for understanding singlet fission and show how the formation of vibronic manifolds with a high density of states facilitates fast and efficient electronic processes in molecular systems.This is the author accepted manuscript. The final version is available from NPG via http://dx.doi.org/10.1038/nchem.237

Research of the autocytokinins influence on the large intestine’s microflora in gastroenterological patients

Вивчено вплив препаратів аутоцитокінів на зміну біологічних властивостей мікроорганізмів, виділених від хворих на неспецифічний виразковий коліт. Установлено стимулювальну дію препаратів аутоцитокінів на ріст представників нормальної мікрофлори товстої кишки та пригнічувальний ефект відносно умовно-патогенних мікроорганізмів. З’ясовано, що аутоцитокіни не виявляють достовірного впливу на зміну антибіотикочутливості мікроорганізмів. Изучено влияние препаратов аутоцитокинив на смену биологических свойств микроорганизмов, выделенных от больных неспецифический язвенный колит. Установлено стимулирующее действие препа-ратов аутоцитокинив на рост представителей нормальной микрофлоры толстой кишки и подавляли ный эффект в отношении условно-патогенных микроорганизмов. Выяснено, что аутоцитокины не проявляют существенного влияния на изменение антибиотикочувствительности микроорганизмов.The autocytokinins’ influence on the change of biological characteristics of the microorganisms secured from patients with non-specific ulcerous colitis has been studied. It has been found that autocytokinin samples have a stimulating influence on the growth of large intestine’s normal microflora and inhibiting effect to opportunistic pathogenic microorganisms. Autocytokinins are proved to have no significant influence on the antibiotic sensitivity of microorganisms

ВЛИЯНИЕ МАГНИТНОГО ПОЛЯ НА ПРОЦЕСС КРИСТАЛЛИЗАЦИИ АЛЮМИНИЕВЫХ РАСПЛАВОВ

Conscious management of metal crystallization processes in order to obtain a defined ingot microstructure is provided by using various physical fields. These fields affect the melt and change its internal state, and therefore its crystallization kinetics. The paper describes the thermodynamics and kinetics of aluminum crystallization when the melt is treated with magnetic field. A quite simple experimental setup is created to allow studying the magnetic field effect on molten aluminum or other metals and alloys. It consists of several main components: (1) electrical furnace; (2) water-cooled copper crucible combined with an electromagnetic coil; (3) mechanical device for rapid movement of the aluminum melt crucible; (4) system for melt temperature monitoring and control and (5) electronics for data recording and processing. It is experimentally proved that magnetic field changes the melt-crystal phase equilibrium temperature, latent heat of phase transition and temperature of melt supercooling at crystallization. It is shown that changes in these parameters reduce the radius of critical nuclei and increases the speed of their origin. Temperature-time relationship are obtained for the crystallization process. It is experimentally proved that aluminum melt treatment with magnetic field reduces the time of crystallization. The analysis of aluminum samples obtained under the influence of magnetic field has shown that their structure has more fine grains compared with untreated samples.Для сознательного управления процессом кристаллизации металлов с целью получения заданной микроструктуры слитка используют различные физические поля, которые при воздействии на расплав изменяют его внутреннее состояние, а значит, и кинетику кристаллизации. В работе описаны термодинамика и кинетика процесса кристаллизации алюминия при обработке расплава магнитным полем. Создана достаточно простая экспериментальная установка, позволяющая изучать процессы воздействия магнитного поля на расплавы алюминия или других металлов и сплавов. Она состоит из нескольких основных узлов: (1) электропечи; (2) водоохлаждаемого медного кристаллизатора, совмещенного с электро- магнитной катушкой; (3) механического устройства для быстрого перемещения тигля с расплавом алюминия; (4) системы контроля и управления температурой расплава; (5) электронной части для записи и обработки информации. Экспериментально установлено, что магнитное поле изменяет температуру фазового равновесия расплав–кристалл, скрытую теплоту фазового перехода и температуру переохлаждения расплава при кристаллизации. Показано, что изменение этих параметров приводит к уменьшению радиуса критических зародышей и увеличению скорости их зарождения. Получены температурно-временные зависимости процесса кристаллизации. Выявлено, что при обработке расплава алюминия магнитным полем время кристаллизации уменьшается. Анализ алюминиевых образцов, полученных под воздействием магнитного поля, показал, что их структура имеет более мелкие зерна, чем у образцов, не подверженных такой обработке