42 research outputs found
A progressive diagonalization scheme for the Rabi Hamiltonian
A diagonalization scheme for the Rabi Hamiltonian, which describes a qubit
interacting with a single-mode radiation field via a dipole interaction, is
proposed. It is shown that the Rabi Hamiltonian can be solved almost exactly
using a progressive scheme that involves a finite set of one variable
polynomial equations. The scheme is especially efficient for lower part of the
spectrum. Some low-lying energy levels of the model with several sets of
parameters are calculated and compared to those provided by the recently
proposed generalized rotating-wave approximation and full matrix
diagonalization.Comment: 8pages, 1 figure, LaTeX. Accepted for publication in J. Phys. B: At.
Mol. Opt. Phy
Quasi-exactly solvable quartic Bose Hamiltonians
We consider Hamiltonians, which are even polynomials of the forth order with
the respect to Bose operators. We find subspaces, preserved by the action of
Hamiltonian These subspaces, being finite-dimensional, include, nonetheless,
states with an \QTR{it}{infinite} number of quasi-particles, corresponding to
the original Bose operators. The basis functions look rather simple in the
coherent state representation and are expressed in terms of the degenerate
hypergeometric function with respect to the complex variable labeling the
representation. In some particular degenerate cases they turn (up to the power
factor) into the trigonometric or hyperbolic functions, Bessel functions or
combinations of the exponent and Hermit polynomials. We find explicitly the
relationship between coefficients at different powers of Bose operators that
ensure quasi-exact solvability of Hamiltonian.Comment: 21 pages, REVTeX 3.0, no figures. In v.2 couple of misprints in
English corrected. To be published in J. Phys. A: Math. Ge
ФОРМАЛИЗАЦИЯ ГРАВИТАЦИОННОЙ МОДЕЛИ ДЛЯ РАСЧЕТА ПАРАМЕТРОВ МЕЖДУГОРОДНИХ ПАССАЖИРСКИХ КОРРЕСПОНДЕНЦИЙ
he paper considers a possibility to apply gravity models for calculation of intercity passenger transport corres- pondences which are implemented with the help of public transport. The Ukraine transportation system has been selected as an object of investigation and this approach extends application possibilities of the obtained results. Calibration coefficients used in calculation of the indicated correspondences are rather important and significant in case of forecasting passenger transport correspondences. Formalization of these factors is necessary for every transportation system if a calculation of pas-senger transport correspondences has been made for it. In this case searching for actual calibration parameters and other coef-ficients as components of gravitational models is a relevant objective of the given paper. Selection of the gravity model va- riant plays rather significant role in solution of this problem. The developed methods for calculation of passenger transport correspondences are proposed for their application in respect of various transport and trip types. The executed research works have made it possible to investigate a process pertaining to providing of services for passenger transportation while using public routes. The obtained characteristics on functioning of the studied system have allowed to assess the possibility for ap-plication of the known methods for calculation of passenger correspondences and analyze the quality of their application. Calibration coefficients have been empirically selected for calculation of the indicated correspondences while using method of gravity modeling. Formalization of previously unexplored parameters of gravity model component provides the possibility to apply the considered approach for calculation of passenger correspondences within the framework of the investigated trans-portion system. This makes it possible to plan and arrange interaction of various transport types and provides new data and knowledge on the studied system.Рассмотрена возможность применения гравитационных моделей для расчетов междугородних пассажирских транспортных корреспонденций, реализуемых при помощи общественного транспорта. В качестве объекта исследования была выбрана пассажирская транспортная система Украины, что расширяет возможности применения полученных результатов. При прогнозировании пассажирских транспортных корреспонденций большое значение имеют величины калибровочных коэффициентов, используемых в расчете указанных корреспонденций. Формализация данных коэффициентов необходима для каждой транспортной системы, для которой производится расчет пассажирских транспортных корреспонденций. Актуальной задачей является поиск фактических параметров калибровочных и других коэффициентов как составляющих гравитационных моделей. Значительную роль в этой проблеме играет выбор варианта гравитационной модели. Разработанные на данный момент способы расчетов пассажирских транспортных корреспонденций предлагают их использование на разных типах транспорта и для разных типов поездок. В результате проведенного изучения исследован процесс оказания услуг по перевозке пассажиров на маршрутах общего пользования. Полученные характеристики функционирования рассмотренной системы позволили оценить возможность применения известных способов расчета пассажирских корреспонденций и качество их применения. Эмпирическим способом подобраны калибровочные коэффициенты используемых при расчете указанных корреспонденций способом применения гравитационного моделирования. Формализация ранее неизученных параметров составляющих гравитационных моделей обеспечивает возможность применения рассмотренного подхода к расчету пассажирских корреспонденций в рамках изученной транспортной системы. Это обеспечивает возможность в планировании и взаимодействии функционирования различных видов транспорта и дает новые знания об изученной системе
General approach to potentials with two known levels
We present the general form of potentials with two given energy levels
, and find corresponding wave functions. These entities are
expressed in terms of one function and one parameter -. We show how the quantum numbers of both levels depend on
properties of the function . Our approach does not need resorting to
the technique of supersymmetric (SUSY) quantum mechanics but automatically
generates both the potential and superpotential.Comment: 14 pages, REVTeX 3.0. In v.2 misprints and inaccuracies in
presentation corrected, discussion of 3-dim. case added. In v.3 misprint in
eq. 41, several typos and inaccuracies in English corrected. To be published
in J. of Phys. A: Math. Ge
Modern information technology in the teaching of pharmacognosy
Sets out guidelines for the teaching of pharmacognosy at Zaporozhye State Medical University for credit-modular system, which contributes to students' motivation to learn throughout the training period. The use of modern information technologies in teaching Pharmacognosy
ИССЛЕДОВАНИЕ СПРОСА НА «ПЕРЕХВАТЫВАЮЩИЕ» ПАРКОВКИ
The paper presents results of demand research for “park and ride” parking lots in the city of Kharkiv. The analysis of the previous research pertaining to demand for “park and ride” parking lots has been carried out in the paper. Disadvantages of the existing methods have been identified as well. A methodology in research on demand for “park and ride” demand for “park and ride” parking lots in the city of Kharkiv according to various characteristics. Distribution of traffic parking lots in the city of Kharkiv has been developed and it is based on modelling of transportation correspondence distribution on traffic networks and a questionnaire survey of car drivers. The obtained data have made it possible to segment the demand for drivers representing suburban areas according to frequency of visits to the city by private cars has been determined in the paper. Drivers’ satisfaction with their efficient movement through the city has been assessed in the paper. Segmentation of traffic demand in the places of possible locations for “park and ride” parking lots has been made according to urban transportation distance and on the basis of modelling distribution of transport correspondences. Quantity demanded for “park and ride” parking lots in the Kharkiv city in dependence to conditions for services has been calculated according to a questionnaire survey of car drivers. It has been established that conditions for parking services significantly determine the demand for “park and ride” parking lots. Analysis of segmentation results concerning the demand for “park and ride” parking lots has shown that under current condions demand for this type of parkings in Kharkiv is at rather low level and they are practically absent in case of 5 km urban transportation distance. Parameters demonstrating dependence of demand for “park and ride” parking lots on transportation distance through the city have beendetermined in the paper. The obtained results of the research are considered as initial data to study demand for “park and ride” parking lots.В статье приведены результаты исследований спроса на «перехватывающие» парковки в городе Харькове. Проанализированы выполненные ранее исследования по проблеме изучения спроса на них и определены недостатки существующих методов. Представлена методика исследований спроса на «перехватывающие» парковки в Харькове, которая основана на моделировании распределения транспортных корреспонденций по сети города и анкетном опросе водителей автомобилей. Полученные в результате исследований данные позволили сегментировать спрос на «перехватывающие» парковки в г. Харькове по различным признакам. Определено распределение транспортного спроса водителей пригородных зон в зависимости от регулярности поездок в город на личных автомобилях. Произведена оценка удовлетворенности водителей эффективностью их передвижений по городу. На основе моделирования распределения транспортных корреспонденций проведено сегментирование транспортного спроса в узлах возможного расположения «перехватывающих» парковок по признаку расстояния сообщения по городу. По данным анкетного опроса водителей автомобилей определена величина спроса на «перехватывающие» парковки в Харькове в зависимости от условий предоставлений услуг. Установлено, что условия предоставления услуг в парковании в значительной степени определяют спрос на «перехватывающие» парковки. Анализ результатов сегментирования спроса на «перехватывающие» парковки показал, что в современных условиях спрос на этот вид парковок в г. Харькове находится на достаточно низком уровне, а при расстоянии сообщения по городу до 5 км практически отсутствует. Определены параметры зависимости спроса на «перехватывающие» парковки от расстояния сообщения по городу. Полученные результаты исследований являются исходными данными для определения потребности в «перехватывающих» парковках
Hypertension control during the COVID-19 pandemic: results of the MMM2021 in Russia
Repetitive quarantines and social restrictions during the coronavirus disease 2019 (COVID-19) pandemic have negatively affected the population health in general, and the control of hypertension (HTN) in particular.Aim. To evaluate the control of HTN in the Russian population during the COVID-19 period based on the results of screening for HTN May Measurement Month 2021 (MMM2021).Material and methods. During May-August 2021, 2491 participants from 11 Russian regions took part in the screening. Participation was voluntary without restrictions on sex. All participants were over 18 years of age. During the screening, blood pressure (BP) was measured three times using automatic and mechanical BP monitors. In addition, a questionnaire was filled out on behavioral risk factors, comorbidities and therapy. HTN was diagnosed with systolic BP ≥140 mmHg and/ or diastolic blood pressure ≥90 mmHg and/or taking antihypertensive therapy. The questionnaire included questions about prior COVID-19, vaccinations and their impact on the intake of antihypertensive drugs.Results. The analysis included data from 2461 respondents aged 18 to 92, of which 963 were men (39,1%). The proportion of hypertensive patients was 41,0%, while among them 59,0% took antihypertensives and 30,9% were effectively treated. In comparison with pre-pandemic period according to MMM2018-2019, the higher proportion of HTN patients in the Russian sample was revealed during MMM2021 (41,0% vs 31,3%, p<0,001) with a comparable proportion of patients receiving antihypertensive therapy (60,7% vs 59,0%, p=0,05) and treatment efficacy (28,7% vs 30,9%, p=0,36). Monotherapy was received in 44,7% of cases, while dual and triple combination therapy — in 30,9% and 14,1%, respectively. The majority of respondents (~90%) did not adjust their antihypertensive therapy during the COVID-19 pandemic.Conclusion. According to HTN screening in Russia, there is persistent ineffective control of HTN, which may be due to both the worsening pattern of behavioral risk factors, limited access to healthcare during COVID-19, and the inertia of physicians and low adherence of patients due to the asymptomatic HTN course in the majority