Types Of Pulsations Research Articles

THE CONDITION OF UTEROPLACENTAL HEMODYNAMICS IN PREGNANT WOMEN AS A RESULT OF THE ASSISTED REPRODUCTIVE TECHNOLOGIES APPLICATION

The aim of research. To study in the dynamics of the First trimester of pregnancy the features of hemodynamics in pregnant women after ART .Materials and methods. 299 pregnant women were comprehensively examined: the main group included 249 women whose pregnancy occurred as a result of the ART application. The control group consisted of 50 pregnant women with spontaneous pregnancy and its physiological course, which were registered in antenatal clinic at 6-8 weeks. The I group included 94 women with tubal-peritoneal factor of infertility, the II group was formed by 87 women with endocrine factor of infertility, and the III group included 68 women whose infertility is caused by the male factor.Common clinical and laboratory tests were performed on pregnant women of the examined groups, which included a General analysis of blood, urine, and Doppler measurements of uterine arteries indicators.The results of the research and their discussion. Determination of utero-placental hemodynamics in women of the main group after the ART application indicates the need for their dynamic monitoring during the I trimester of pregnancy.As a result of the analysis of the obtained data, it was found that the highest intensity of hemodynamics in the uterine artery basin at 11-12 weeks of gestation was registered in the group of patients with the physiological course of pregnancy. Thus, the systolic-diastolic ratio in the right and left uterine arteries in these patients was 1,9 (1,8-2,7) and 2,1 (1,9-2,6), respectively.In contrast to the subjects with uncomplicated course (group IV), in pregnant women after the ART application analyzed indicators were significantly higher (1,6 – 1,9 times, p<0,0001). The systolic-diastolic ratio in the right uterine artery in group III was 3,0 (2,4-3,5), and in group I – 3,3 (3,1- 3,4). Similar data were obtained during the curves of blood flow rates analyses the in the left uterine artery – 2,9 (2,1-3,5) and 3,0 (2,7-3,6), respectively.The highest peripheral resistance, both in the right (3,6 (3,4-3,7)) and in the left (3,5 (3,2-3,8)) uterine arteries, was registered naturally in group II pregnant women.Own research has shown that the vast majority of 36 (72,0%) patients with uncomplicated course and favorable gestational outcome at 11-12 weeks of pregnancy did not register blood flow in the interval space. Less than one-third of the patients - 14 (28,0%) color Doppler mapping revealed continuous venous-like blood flow. Arterioid-like pulsating type of flow does not reveal any one pregnant in this group.In contrast, the vast majority - 50 (73,5%) of group I pregnant women registered two types of blood flow in the intervertebral space: pulsating arterioid and continuous venous flow. Only 18 (26,5%) patients of this group the blood flow in intervention space was not determined.Conclusions. The results of the research allow us to attribute Doppler to highly informative research methods, which makes it possible to predict pregnancy complications in pregnant women as a result of art quite effectively. Pregnant women with no hemodynamic abnormalities in the utero-placental pool in combination with normal ultrasound data, including assessment of the fetal condition, constitute a group with a truly low risk of an adverse outcome

On the first δ Sct–roAp hybrid pulsator and the stability of p and g modes in chemically peculiar A/F stars

ABSTRACT Strong magnetic fields in chemically peculiar A-type (Ap) stars typically suppress low-overtone pressure modes (p modes) but allow high-overtone p modes to be driven. KIC 11296437 is the first star to show both. We obtained and analysed a Subaru spectrum, from which we show that KIC 11296437 has abundances similar to other magnetic Ap stars, and we estimate a mean magnetic field modulus of 2.8 ± 0.5 kG. The same spectrum rules out a double-lined spectroscopic binary, and we use other techniques to rule out binarity over a wide parameter space, so the two pulsation types originate in one δ Sct–roAp hybrid pulsator. We construct stellar models depleted in helium and demonstrate that helium settling is second to magnetic damping in suppressing low-overtone p modes in Ap stars. We compute the magnetic damping effect for selected p and g modes, and find that modes with frequencies similar to the fundamental mode are driven for polar field strengths ≲4 kG, while other low-overtone p modes are driven for polar field strengths up to ∼1.5 kG. We find that the high-order g modes commonly observed in γ Dor stars are heavily damped by polar fields stronger than 1–4 kG, with the damping being stronger for higher radial orders. We therefore explain the observation that no magnetic Ap stars have been observed as γ Dor stars. We use our helium-depleted models to calculate the δ Sct instability strip for metallic-lined A (Am) stars, and find that driving from a Rosseland mean opacity bump at ∼5 × 104 K caused by the discontinuous H-ionization edge in bound-free opacity explains the observation of δ Sct pulsations in Am stars.

On the Calculation of the Main Characteristics of the Pulsation Crystallizer

The article considers the problem of calculation and evaluation of the efficiency of industrial apparatus, meaning in particular the columns of pulsation type. A numerical calculation method for determining the main hydrodynamic characteristics of the pulsating crystallizer is proposed. Numerical results are obtained for analyzing the pulsation mode and determining the possibility of improving the design of the crystallizer. Recommendations for improving the operation of the crystallizer are given.

Синхронность сейсмогравитационных пульсаций

Введение: Пульсации силы тяжести были впервые обнаружены при обработке стационарных наблюдений на Геодинамическом полигоне РАН в г. Бишкеке (2014 г.). Как оказалось, такие же пульсации характерны для сейсмических колебаний, которые синхронно совпадали с гравиметрическими пульсациями. Методика: Сейсмические и гравиметрические наблюдения осложнены влиянием Луны и Солнца. Основной задачей при обработке является исключение этого влияния. Исключение лунно-солнечного влияния производится путем теоретических расчетов лунно-солнечных вариаций силы тяжести и их временного градиента. Кроме того, сейсмо-гравиметрические измерения подвержены влиянию атмосферного давления и температуры воздуха. Метеорологические помехи устраняются использованием метода осреднения. Результаты и обсуждение: Анализ сейсмогравитационных пульсаций на различных континентах показал, что пульсации полностью синхронны между собой. Такая синхронность характерна в основном для внутриконтинентальных станций. Таким образом, на основании изучения сейсмогравитационных пульсаций можно утверждать о наличии двух типов источников. Первый тип пульсаций связан с ударами метеорных потоков по земной атмосфере, для него присущ планетарный характер. В прибрежных зонах и в океане дополнительно возникают пульсации за счет атмосферных процессов (тайфуны, циклоны и т.д.) Выводы: Полученные результаты в дальнейшем могут быть использованы при изучении внутреннего строения Земли, для определения мощности метеорных потоков и повышения точности гравиметрических измерения.

Invisible Soliton Pulsation: Visualizing the “Invisible” Soliton Pulsation in an Ultrafast Laser (Laser Photonics Rev. 14(4)/2020)

In article number 1900317, Wen-Cheng Xu, Zhi-Chao Luo, and co-workers unveil a novel type of soliton pulsation in an ultrafast laser. The observed pulsating dynamics cannot be resolved by routine diagnostic methods because of the almost unchanged energy, which is termed as “invisible” soliton pulsation. Here, a real-time spectroscopy technique is skillfully applied to identify the newly discovered pulsating dynamics. The cover shows an artistic representation of the pulsating dynamics in both the spectral and temporal domains.

Atrial myxoma with cerebellar signs: a case report

BackgroundAtrial myxoma remains a rare clinical entity with an incidence of surgically resected cases of 0.5–0.7 per million population and prevalence of < 5 per 10,000. It typically manifests in woman after third decade of life; symptoms vary greatly and may present with arrhythmia, intracardiac flow obstruction, embolic phenomenon, and associated constitutional symptoms. Neurological complications associated with atrial myxoma most frequently include cerebral infarct due to embolus. Cerebellar involvement is very rare and only a few cases have been reported in the literature.Case presentationA 55-year-old Brahmin man with no history of diabetes mellitus and hypertension, presented with complaints of dizziness, headache, vomiting, double vision, and unsteadiness of gait for 2 weeks. His headache was sudden in onset, of a pulsating type and localized on left temporal side. Vomiting was projectile and bilious. Double vision was present in all directions of gaze and he had uncoordinated movement of his body and tilting to the left side. On examination, his cerebellar functions were impaired. He was thoroughly investigated for the cause of stroke after abnormal magnetic resonance imaging results with normal computed tomography angiography of his brain. Echocardiography and computed tomography of his chest showed a mass attached to intra-atrial septum and prolapsing through mitral valve, which was suggestive of left atrial myxoma. Five days following admission, he developed abdominal pain due to thromboembolism causing splenic and renal infarct.ConclusionAlthough rare, atrial myxoma has to be considered a cause of stroke and other embolic phenomenon causing multiorgan infarctions. Early and timely diagnosis of the condition can prevent further recurrence and inappropriate anticoagulant therapy. It would be pertinent to have echocardiography done in patients who present with a stroke, arrhythmias, and other constitutional symptoms. The tumor once detected must be removed surgically as early as possible, which not only reduces serious thromboembolic complications but can be potentially curative.

Diffuse and Pulsating Aurora

This chapter reviews fundamental properties and recent advances of diffuse and pulsating aurora. Diffuse and pulsating aurora often occurs on closed field lines and involves energetic electron precipitation by wave-particle interaction. After summarizing the definition, large-scale morphology, types of pulsation, and driving processes, we review observation techniques, occurrence, duration, altitude, evolution, small-scale structures, fast modulation, relation to high-energy precipitation, the role of ECH waves, reflected and secondary electrons, ionosphere dynamics, and simulation of wave-particle interaction. Finally we discuss open questions of diffuse and pulsating aurora.

Modeling of wave processes when the heterogeneous flow is moving in a low-frequency magnetic peristaltic pump of pulsating type

The paper presents the results of a multiphysical simulation of the movement of a heterogeneous flow in the working channel of a magnetic peristaltic pump, which describes in detail the state of the flow particles at all points of the considered area at different points in time, taking into account the design parameters of the channel. The developed model made it possible to reveal a rational range of parameters in the conditions of the wave variation of the internal cross section of the working channel of a magnetic peristaltic pump in a running magnetic field.

Bubble and conical forms of vortex breakdown in swirling jets

Experimental investigations of laminar swirling jets had revealed a new form of vortex breakdown, named conical vortex breakdown, in addition to the commonly observed bubble form. The present study explores these breakdown states that develop for the Maxworthy profile (a model of swirling jets) at inflow, from streamwise-invariant initial conditions, with direct numerical simulations. For a constant Reynolds number based on jet radius and a centreline velocity of 200, various flow states were observed as the inflow profile’s swirl parameter $S$ (scaled centreline radial derivative of azimuthal velocity) was varied up to 2. At low swirl ($S=1$) a helical mode of azimuthal wavenumber $m=-2$ (co-winding, counter-rotating mode) was observed. A ‘swelling’ appeared at $S=1.38$, and a steady bubble breakdown at $S=1.4$. On further increase to $S=1.5$, a helical, self-excited global mode ($m=+1$, counter-winding and co-rotating) was observed, originating in the bubble’s wake but with little effect on the bubble itself – a bubble vortex breakdown with a spiral tail. Local and global stability analyses revealed this to arise from a linear instability mechanism, distinct from that for the spiral breakdown which has been studied using Grabowski profile (a model of wing-tip vortices). At still higher swirl ($S=1.55$), a pulsating type of bubble breakdown occurred, followed by conical breakdown at 1.6. The latter consists of a large toroidal vortex confined by a radially expanding conical sheet, and a weaker vortex core downstream. For the highest swirls, the sheet was no longer conical, but curved away from the axis as a wide-open breakdown. The applicability of two classical inviscid theories for vortex breakdown – transition to a conjugate state, and the dominance of negative azimuthal vorticity – was assessed for the conical form. As required by the former, the flow transitioned from a supercritical to subcritical state in the vicinity of the stagnation point. The deviations from the predictions of the latter model were considerable.

Pulsating type entire solutions originating from three fronts for a bistable reaction–advection–diffusion equation in periodic media

The present paper is to study the pulsating type entire solutions of a reaction–advection–diffusion equation in periodic media with bistable nonlinearity. It is well-known that the equation has three different types of pulsating traveling wavefronts: a bistable front and two families of monostable fronts. The existence of entire solutions originating from two different types of those fronts has also been established by Bu et al. (2016).It is natural to ask whether there are entire solutions originating from three fronts. In this paper, we construct two different types of pulsating entire solutions with merging three fronts. These entire solutions behave as t→−∞ like a monostable and bistable pulsating fronts coming from opposite directions and like another monostable pulsating front between these two fronts.

Transient behaviors of pure soliton pulsations and soliton explosion in an L-band normal-dispersion mode-locked fiber laser.

As one of the most striking localized structures in dissipative systems, pulsating soliton has been widely studied in theory but rarely observed in experiments. Here, three typical types of soliton pulsations are experimentally demonstrated in an L-band normal-dispersion mode-locked fiber laser via the dispersive Fourier transform (DFT) technique. According to the distinctive features, they are classified as single-periodic pulsating soliton, double-periodic pulsating soliton and soliton explosion. These pulsations have common features such as energy oscillation, bandwidth breathing and temporal shift. However, the pulse is repeated every two oscillations for double-periodic pulsating soliton. When it comes to soliton explosion, because of the intermittent overdriven nonlinear effect induced by the extreme energy oscillation, the spectrum cracks into pieces at a periodic manner. To the best of our knowledge, it is the first time that both pure soliton pulsations and soliton explosion are observed experimentally in the same fiber laser. The results will enhance a more comprehensive understanding for the soliton pulsating phenomena.

Effect of the pulsation type (alternate or simultaneous) on milk yield and health status of the mammary gland of Murciano-Granadina goats

Recent research into how the pulsation type affects goat milking concluded that alternate pulsation (AP) and simultaneous pulsation (SP) similarly affect the milking efficiency (milking duration and milking fractioning) and teat end condition after milking when both pulsations are employed in short-term experiments. However, the use of SP in high pipeline milking machines led to higher vacuum fluctuations, which, in the long term, may entail a potential risk factor for the mammary gland health status. The aim of this work was to study how AP and SP affect the milk yield, mammary gland health status, and milk composition of goats in the long term, during a complete lactation period, in a high pipeline milking machine. With this objective, 100 Murciano-Granadina goats with similar parturition dates (4 ± 1 postpartum weeks) were divided into 2 similar groups (50 goats per group) according their parity, milk yield, mammary gland health status, and milking duration (after a 15-d pre-experimental period). Throughout the experimental period (7 mo), one group was milked using SP and the other group using AP. Every month, samplings were carried out of the variables related to sanitary status of the mammary gland, milk fractioning, milking duration, average and maximum milk flows, milk composition, teat end status, vacuum fluctuations at the short milk tube during milking, and pulsation tests. Results showed that the use of SP in a high pipeline milking machine showed higher vacuum fluctuations without involving any difference in the other variables studied. We concluded that the use of AP in the milking of Murciano-Granadina goats offers little improvement of the milking performance and increases the investment required for installation and maintenance of the milking machines.

Development and performance evaluation of low pulsation type water hydraulic motor practicable under a radiation environment

Development and performance evaluation of low pulsation type water hydraulic motor practicable under a radiation environment

Design and development of low pulsation type water hydraulic motor practicable under a radiation environment

Design and development of low pulsation type water hydraulic motor practicable under a radiation environment

Particle Acceleration by Induced Electric Fields in Course of Electric Current Oscillations in Coronal Magnetic Loops

A mechanism for acceleration of electrons driven by the oscillations of the electric current in solar magnetic loops is considered. The magnetic loop is presented as an equivalent RLC-circuit with the electric current generated by convective motions in the photosphere. Eigen oscillations of the current in a loop induce the electric field directed along to the loop axis. It is shown that pulsating type III bursts and the sudden reductions that occur in the course of type IV continuum in solar flares provide evidence for acceleration and storage of energetic electrons in the coronal magnetic loops. Energization rate of electrons accelerated by sub-Dreicer electric field are determined. The energy spectra of fast electrons under both intermediate and strong regimes of pitch-angle diffusion are discussed. Two examples of the electron acceleration in the pulsating type III solar bursts are considered. We also discuss the efficiency of suggested mechanism as compared with the electron acceleration during 5-min photospheric oscillations and with the acceleration driven by the magnetic Rayleigh-Taylor instability.

V. A. Troitskaya: the Founder of the Russian School of Geomagnetic Pulsations

A thorough investigation of short-period oscillations in the Earth’s magnetic field as a fundamental natural process of the magnetospheric plasma began in Russia after V.A. Troitskaya established two oscillatory regimes in the geomagnetic field, namely, the regimes of continuous (Pc) and irregular pulsations (Pi). For studying these pulsations, 19 stations recording the telluric currents were installed during the International Geophysical Year (IGY, 1957–1959) on Troitskaya’s initiative. One of these stations was the Borok station. Subsequently, Borok has become the basic site for investigating geomagnetic pulsations and the main center for studying the short-period pulsations (SPPs) in the Earth’s magnetic field. This is the Borok scientific station where the key fundamental regularities of different types of geomagnetic pulsations were established. Troitskaya led and actively participated these works. Troitskaya organized and conducted the first complex geomagnetic observations in the world at the conjugate points Sogra (Arkhangelsk region, Russia) and Kerguelen (Indian Ocean). These studies were initially tested at the Borok observatory, where it was established that the wave packets of Pc1 geomagnetic pulsations are alternately observed in the northern and southern hemispheres in contrast to the other pulsation types which simultaneously occur in both hemispheres. The studies carried out at Borok promoted the establishment of a new direction in geophysics—diagnostics of the state of the magnetosphere based on the ground observations of geomagnetic pulsations. The analysis of simultaneous observations of the geomagnetic pulsations at polar latitudes of the Arctic and Antarctic was also for the first time conducted at the Borok observatory. This analysis revealed the main characteristics of wave phenomena at the geomagnetic poles and in the vicinity of the projection of the dayside polar cusp. Thus, for the first time in the world, Troitskaya and her Borok colleagues established the key patterns of the oscillatory regimes in the geomagnetic field of the Earth. This laid the basis for the further experimental and theoretical investigations which have shown that SPPs play a leading role in the dynamics of the magnetospheric plasma. In this paper we also list of 60 of Troitskaya’s main publications.

Visualization Study of Startup Modes and Operating States of a Flat Two-Phase Micro Thermosyphon

The flat two-phase thermosyphon has been recognized as a promising technique to realize uniform heat dissipation for high-heat-flux electronic devices. In this paper, a visualization experiment is designed and conducted to study the startup modes and operating states in a flat two-phase thermosyphon. The dynamic wall temperatures and gas–liquid interface evolution are observed and analyzed. From the results, the sudden startup and gradual startup modes and three quasi-steady operating states are identified. As the heat load increases, the continuous large-amplitude pulsation, alternate pulsation, and continuous small-amplitude pulsation states are experienced in sequence for the evaporator wall temperature. The alternate pulsation state can be divided into two types of alternate pulsation: lengthy single-large-amplitude-pulsation alternated with short multiple-small-amplitude-pulsation, and short single-large-amplitude-pulsation alternated with lengthy multiple-small-amplitude alternate pulsation state. During the continuous large-amplitude pulsation state, the bubbles were generated intermittently and the wall temperature fluctuated cyclically with a continuous large amplitude. In the alternate pulsation state, the duration of boiling became longer compared to the continuous large-amplitude pulsation state, and the wall temperature of the evaporator section exhibited small fluctuations. In addition, there was no large-amplitude wall temperature pulsation in the continuous small-amplitude pulsation state, and the boiling occurred continuously. The thermal performance of the alternate pulsation state in a flat two-phase thermosyphon is inferior to the continuous small-amplitude pulsation state but superior to the continuous large-amplitude pulsation state.

Signs of rotating equatorial density enhancements around SRb pulsators

AbstractWe observed the circumstellar environments (CSEs) of the semiregular AGB stars L2 Puppis, R Doradus and EP Aquarii with ALMA. (1) The molecular emission in the L2 Pup nebula reveals an edge-on rotating disk. (2) PV diagrams of the 28SiO emission in the inner CSE of R Dor expose a pattern pointing to an inclined rotating disk. (3) The CO emission in the CSE of EP Aqr reveals a nearly face-on equatorial density enhancement (EDE). The inner EDE strongly resembles theoretical wind-Roche-lobe-overflow models. The SiO emission points to a potential companion. The combination of (1), (2) and (3) suggests that a link may exist between the type of AGB pulsations and the morphological nature of the CSE.

OGLE-ing the Magellanic System: Three-Dimensional Structure

AbstractWe present a three-dimensional structure of the Magellanic System using over 9 000 Classical Cepheids and almost 23 000 RR Lyrae stars from the OGLE Collection of Variable Stars. Given the vast coverage of the OGLE-IV data and very high completeness of the sample, we were able to study the Magellanic System in great details.We very carefully studied the distribution of both types of pulsators in the Magellanic Bridge area. We show that there is no evident physical connection between the Clouds in RR Lyrae stars distribution. We only see the two extended structures overlapping. There are few classical Cepheids in the Magellanic Bridge area that seem to form a genuine connection between the Clouds. Their on-sky locations match very well young stars and neutral hydrogen density contours. We also present three-dimensional distribution of classical pulsators in both Magellanic Clouds.

Design optimisation of high sensitivity MEMS piezoresistive intracranial pressure sensor using Taguchi approach

MEMS piezoresistive pressure sensors have been contemporarily used to measure intracranial pressure. Since an intracranial signal is of the pulsating type, the microsensor must be very sensitive to detect these changes. The sensitivity of the existing MEMS piezoresistive intracranial pressure sensors are in the range of 2 µV/V/mmHg to 0.17 mV/V/mmHg. Factors influencing the sensitivity and linearity of the sensor include the diaphragm thickness, the shape and placement of the piezoresistors, and the doping concentration. This paper will discuss the incorporation of these factors, which were tested to obtain higher sensitivity silicon-based piezoresistive intracranial pressure sensor, while maintaining the linearity of the sensor. In order to achieve this objective, the Taguchi robust design method of L27 orthogonal array was employed. The sensing outputs of these designs, with different combinations of factors were determined through simulations using COMSOL Multiphysics. The results indicated that the diaphragm thickness and perpendicular piezoresistors play important roles in the sensitivity performance of the MEMS piezoresistive intracranial pressure sensor. The findings also showed that the doping concentration of the piezoresistors have significant effect on the linearity performance of the sensor. Consequently, the design that consolidated the 3-turns (perpendicular) and 0-turn (parallel) meander shaped piezoresistors of 1017 cm−3 dopant concentration on a 2 μm diaphragm thickness was found to be the optimum design, with sensitivity of 0.1272 mV/V/mmHg and linearity of 99%. This design has been proven to be an improved version for the small diaphragm piezoresistive intracranial pressure sensor.