Origin Of Jets Research Articles

Theoretical breakthrough in the dynamics of a jet in a free-stream flow around a corner

For the first time, the laminar jet in a free-stream flow around a corner with/without a moving wall condition (as it assists the flow) is studied theoretically. The corner may contract the streamlines or expand them depending on the angle of inclination. In the context of incompressibility, it is presented a composite non-similar transformation of the Navier-Stokes (N-S) equations in Cartesian space to approximately decipher the nature of the boundary layer flow over the entire physical domain; i.e. 0 ≤ x, y < ∞. The transformed Partial Differential Equations (PDEs) are then solved by an in-house MATLAB code, which employs an implicit algorithm of a tridiagonal form with quasi-linearization technique. For a stationary wall, as the negative angle of the corner meets Falkner-Skan (F-S) limitation and expands beyond, the predictive model starts to show a critical location, which reveals directly the flow separation point. This critical location moves toward the jet origin as the angle of inclination becomes more negative. Here, these locations are extracted as a function of the inclination parameter in order to manifest the suitability of a jet to delay boundary layer separation. A similar scenario also applies to the moving wall case. In this case, it was recorded that a moving wall condition delays separation for a considerable distance. It should be pointed out that up to date, there is no theoretical investigation on this specific flow geometry despite the many associated applications; and the limited available reports on an analogous flow geometry are those from the Computational Fluid Dynamics (CFD) and on a case by case basis. More specifically, the present geometry is quite similar to the flow passing the way down to the trailing edge of an airfoil, with a jet generator mechanism such as Dielectric Barrier Discharge (DBD) plasma actuator to delay flow separation on the backside of the airfoil.Here, by the use of the theoretical non-similarity concept empowered by some recent advancements (see Jafarimoghaddam, 2020 and Jafarimoghaddam, 2021), the fundamental problem of a jet discharged in the lower boundary of a freestream flow over a wedge is successfully solved.This theoretical breakthrough suggests promising avenues for the future design of airfoils with moving parts/flaps as an innovative step forward to enhance maneuverability of the flying objects.

Making Fanaroff-Riley I radio sources

Extragalactic radio sources appear under different morphologies, the most frequent ones are classified as Fanaroff-Riley type I (FR I), typically with lower luminosities, and Fanaroff-Riley type II, (FR II), typically more luminous. This simple classification, however, has many exceptions that we intend to investigate. Following previous analyses in the three-dimensional Hydrodynamic and Magneto-Hydrodynamic limits, we extend the numerical investigation to the Relativistic Magneto-Hydrodynamic regime, to include sources whose jet kinetic power sets in the range that separates FR Is from FR IIs. We consider weakly and mildly relativistic, underdense, supersonic jets that propagate in a stratified medium. In the model, the ambient temperature increases with distance from the jet origin maintaining constant pressure. We present three cases with low, high and intermediate kinetic luminosity that evolve into different morphologies. We find that the resulting morphology can be highly time dependent and that, apart from the jet power, the jet-to-ambient density ratio and the magnetization parameter play a crucial role in the jet evolution as well.

GRMHD Simulations and Modeling for Jet Formation and Acceleration Region in AGNs

Relativistic jets are collimated plasma outflows with relativistic speeds. Astrophysical objects involving relativistic jets are a system comprising a compact object such as a black hole, surrounded by rotating accretion flows, with the relativistic jets produced near the central compact object. The most accepted models explaining the origin of relativistic jets involve magnetohydrodynamic (MHD) processes. Over the past few decades, many general relativistic MHD (GRMHD) codes have been developed and applied to model relativistic jet formation in various conditions. This short review provides an overview of the recent progress of GRMHD simulations in generating relativistic jets and their modeling for observations.

Hemodynamics of Mitral Stenosis

Hemodynamic is the intravascular pressure and flow that circulate blood throughout the body. In both the venous and arterial compartments, variations in pressure and flow will necessarily affect each other. Flow and pressure within and between the arterial and venous compartments are influenced by hemodynamic on a beat-to-beat basis. Hemodynamic values that are treated in one compartment are dependent on the state of the other compartments. There are several curved proximal isovelocity surface areas as the streamlines of flow approach the stenotic orifice. A stenotic valve's spatial flow velocity profile depends on its anatomy, inlet geometry, and degree of flow acceleration. A patient with Mitral Stenosis (MS) experiences a pressure gradient from the left atrium to the left ventricle that propels the flow abruptly across the stenotic orifice. An arc-shaped flow profile is created, and the atrioventricular valve will therefore have a hemi elliptical velocity profile. At the level of narrowed stenotic orifices, high-velocity jets form in laminar flow when it reaches the vena contracta, the narrowest cross-sectional area downstream from the anatomic orifice, the flow profile in cross-section is relatively flat at the jet's origin and remains flat until the jet reaches the anatomic orifice. Distally from the stenotic region, the blood flow becomes disorganized with multiple velocities and directions. Stenotic mitral valves exhibit thickened leaflets with a reduced excursion. In this review, we will discuss the challenges and changes which occur in hemodynamic of MS.

The Relativistic Jet and Central Engine of Fermi Blazars

Abstract The origin of jets is one of the most important issues concerning active galactic nuclei, yet it has remained obscure. In this work, we made use of information from emission lines, spectral energy distributions, and Fermi–LAT γ-ray emission to construct a blazar sample that contains 667 sources. We note that jet power originations are different for BL Lacertae objects (BL Lacs) and flat-spectrum radio quasars (FSRQs). The correlation between jet power P jet and the normalized disk luminosity L Disk/L Edd shows a slope of −1.77 for BL Lacs and a slope of 1.16 for FSRQs. The results seem to suggest that BL Lac jets are powered by extracting black hole (BH) rotation energy, while FSRQ jets are mostly powered by accretion disks. Meanwhile, we find the accretion ratio M ̇ / M ̇ Edd increases with the normalized γ-ray luminosity. Based on this, we propose a dividing line, log ( L BLR / L Edd ) = 0.25 log ( L γ / L Edd ) − 2.23 , to separate FSRQs and BL Lacs in the diagram of L BLR/L Edd against L γ /L Edd using a machine-learning method; the method gives an accuracy of 84.5%. In addition, we propose an empirical formula, M BH / M ☉ ≃ L γ 0.65 / 21.46 , to estimate BH mass based on a strong correlation between γ-ray luminosity and BH mass. Strong γ-ray emission is typical in blazars, and the emission is always boosted by a Doppler-beaming effect. In this work, we generate a new method to estimate a lower limit of Doppler factor δ and give δ BL Lac = 7.94 and δ FSRQ = 11.55.

Abstract 13922: Association Between Quadrileaflet Tricuspid Valve and Location of Regurgitation Jet Origin in Patients With Functional Severe Tricuspid Regurgitation

Introduction: It has been known that the posterior leaflet of the tricuspid valve (PTL) has several indentations or clefts in its free edge, giving the tricuspid valve (TV) equal to or more than four leaflets appearance. However, little is known about whether the indentations or clefts can be a location of tricuspid regurgitation (TR) jet origin in severe TR. Hypothesis: This study aimed to investigate the association between quadrileaflet TV and location of TR jet origin in patients with functional severe TR. Methods: We retrospectively studied 85 functional severe TR patients who underwent 3D transesophageal echocardiography which was performed using the EPIQ7 ultrasound system with a X8-2t probe (Philips Medical Systems). The morphology of the TV leaflets was ascertained using 3D volume-rendered images. Clefts extending over 50% of the depth of the leaflets were determined as a landmark between 2 adjacent leaflets. The location of TR jet origin and vena contracta area (VCA) were ascertained using real-time 3D color Doppler images. All images were analyzed by using QLAB 3D quantification software (Philips Medical Systems). Results: In 85 functional severe TR patients, a total of 3 (4%) patients with bileaflet, 60 (71%) patients with trileaflet and 22 (26%) patients with quadrileaflet were identified. All quadrileaflet TV had dichotomous PTLs (PTL 1 and PTL 2) and there was no patient who had equal to or more than five leaflets. In 22 patients with quadrileaflet, 10 (45%) patients showed TR jet origin located between PTL 1 and PTL 2 (Figure A). Also, quadrileaflet TV patients with TR jet origin located between PTL 1 and PTL 2 had significantly larger VCA than those without (185 vs. 62 mm2, P&lt;0.001, Figure B). Conclusions: In patients with functional severe TR, one fourth patients showed quadrileaflet TV morphology. Furthermore, TR jet origin located between PTL 1 and PTL 2 can be seen only in a condition of TR beyond severe.

Central liquid jet emanating from an impacting drop on superheated laser-ablated surfaces

Drop impacts on superheated textured surfaces have been studied extensively due to the unique characteristics arising from the roughness, which can be controlled through texturing features. The characteristics include novel modifications of the wettability and boiling regimes. The increased roughness of a textured surface also results in an unusual phenomenon where a central liquid jet emanates from an impinging drop. The central jet can interfere with the designated objective of textures or can be used in other applications, but it has rarely been reported and analyzed. Therefore, this study provides detailed and quantitative information on the central jet. With sufficient spatial and temporal resolutions, the impact and boiling behaviors including the central jet are clearly acquired and explained. The time-resolved height and speed of the jets are correlated to varying impact conditions such as the impact momentum of droplets, roughness and temperature of the surfaces. To understand and estimate the origin of the central jet, we also analyze several key findings, such as the motion of a cluster of vapor bubbles and the rim pattern of contact boiling. In addition, a hypothetical mechanism of the jet formation is proposed based on experimental evidence and a simplified heat transfer situation.

The first interferometric survey of massive YSOs in the K-band

Context. Circumstellar discs are essential for the formation of high mass stars, while multiplicity, and in particular binarity, appears to be an inevitable outcome, as the vast majority of massive stars (&gt;8 M⊙) are found in binaries (up to 100%). Our understanding of the innermost regions of accretion discs around massive stars and the binarity of high-mass young stars is sparse because of the high spatial resolution and sensitivity required to trace these rare and distant objects. Aims. We aim to spatially resolve and constrain the sizes of the dust and ionised gas emission from the innermost regions of a sample of massive young stellar objects (MYSOs) for the first time, and to provide high-mass binary statistics for young stars at 2–300 au scales using direct interferometric measurements. Methods. We observed six MYSOs using long-baseline near-infrared K-band interferometry on the VLTI (GRAVITY, AMBER) in order to resolve and characterise the 2.2 μm hot dust emission originating from the inner rim of circumstellar discs around MYSOs, and the associated Brγ emission from ionised gas. We fitted simple geometrical models to the interferometric observables, and determined the inner radius of the dust emission. We placed MYSOs with K-band measurements in a size–luminosity diagram for the first time, and compared our findings to their low- and intermediate-mass counterparts (T Tauris and Herbig AeBes). We also compared the observed K-band sizes (i.e. inner rim radius) to the sublimation radius predicted by three different disc scenarios: a classical thick flattened structure with oblique heating in action, and direct heating from the protostar via an optically thin cavity with and without backwarming effects. Lastly, we applied binary geometries to trace close binarity among MYSOs. Results. The characteristic size of the 2.2 μm continuum emission towards this sample of MYSOs shows a large scatter at the given luminosity range. When the inner sizes of MYSOs are compared to those of lower mass Herbig AeBe and T Tauri stars, they appear to follow a universal trend in that the sizes scale with the square-root of the stellar luminosity. The Brγ emission originates from a similar or somewhat smaller and co-planar area compared to the 2.2 μm continuum emission. We discuss this new finding with respect to a disc-wind or jet origin. Finally, we report an MYSO binary fraction of 17–25% at milli-arcsecond separations (2–300 au). Conclusions. The size–luminosity diagram indicates that the inner regions of discs around young stars scale with luminosity independently of the stellar mass. The observed fraction of MYSO binaries in K-band is almost ‘flat’ for a wide range of separations (2–10 000 au). At the targeted scales (2–300 au), the MYSO binary fraction is lower than what was previously reported for the more evolved main sequence massive stars, which, if further confirmed, could implicate predictions from massive binary formation theories. Lastly, with this study, we can finally spatially resolve the crucial star–disc interface in a sample of MYSOs, showing that au-scale discs are prominent in high-mass star formation and are similar to their low-mass equivalents, while the ionised gas can be linked to disc wind and disc accretion models similar to Herbig AeBes.

Septaly Oriented Mild Aortic Regurgitant Jets Negatively Influence Left Ventricular Blood Flow-Insights From 4D Flow MRI Animal Study.

Objectives: Paravalvular leakage (PVL) and eccentric aortic regurgitation remain a major clinical concern in patients receiving transcatheter aortic valve replacement (TAVR), and regurgitant volume remains the main readout parameter in clinical assessment. In this work we investigate the effect of jet origin and trajectory of mild aortic regurgitation on left ventricular hemodynamics in a porcine model.Methods: A pig model of mild aortic regurgitation/PVL was established by transcatheter piercing and dilating the non-coronary (NCC) or right coronary cusp (RCC) of the aortic valve close to the valve annulus. The interaction between regurgitant blood and LV hemodynamics was assessed by 4D flow cardiovascular MRI.Results: Six RCC, six NCC, and two control animals were included in the study and with one dropout in the NCC group, the success rate of model creation was 93%. Regurgitant jets originating from NCC were directed along the ventricular side of the anterior mitral leaflet and integrated well into the diastolic vortex forming in the left ventricular outflow tract. However, jets from the RCC were orientated along the septum colliding with flow within the vortex, and progressing down to the apex. As a consequence, the presence as well as the area of the vortex was reduced at the site of impact compared to the NCC group. Impairment of vortex formation was localized to the area of impact and not the entire vortex ring. Blood from the NCC jet was largely ejected during the following systole, whereas ejection of large portion of RCC blood was protracted.Conclusions: Even for mild regurgitation, origin and trajectory of the regurgitant jet does cause a different effect on LV hemodynamics. Septaly oriented jets originating from RCC collide with the diastolic vortex, reduce its size, and reach the apical region of the left ventricle where blood resides extendedly. Hence, RCC jets display hemodynamic features which may have a potential negative impact on the long-term burden to the heart.

3D Space‐Time Adaptive Hybrid Simulations of Magnetosheath High‐Speed Jets

AbstractWe study the generation and evolution of spatially localized dynamic plasma pressure enhancements in the magnetosheath (high‐speed jets) by carrying out three‐dimensional hybrid simulations of the Earth's dayside magnetosphere with a novel, space‐time adaptive code, HYPERS. High‐speed jets are shown to occur downstream of quasi‐parallel bow shocks under southward and northward quasi‐radial interplanetary magnetic field conditions. The physical properties and three‐dimensional morphology of simulation jets are found to be consistent with general statistical knowledge acquired from the satellite observations. We discuss a “magnetokinetic” mechanism for jet origin whereby the compression of solar wind plasma and its penetration into the magnetosheath is tied to the turbulence‐driven magnetic field perturbations. We compare three‐dimensional jets to dynamic pressure structures observed in two‐dimensional hybrid simulations and demonstrate the impact of large jets on the magnetopause and the cusp.

Zooming into the Collimation Zone in a Massive Protostellar Jet

Abstract Protostellar jets have a fundamental role at the earliest evolution of protostars of all masses. In the case of low-mass (≲8 M ⊙) protostars, strong observational evidence exists that the launching and collimation is due to the X- and/or disk-wind mechanisms. In these models, it is the protostar/disk system that creates all the necessary conditions to launch and collimate the jets near the protostar via strong magnetic fields. The origin of jets from more massive protostars has been investigated much less, in part because of the difficulty of resolving the collimation zone in these more distant objects. Here we present the highest angular resolution observations of a jet powered by a massive protostar, the Cep A HW2 radio jet. We imaged the radio emission at projected distances of only ∼20 au from the protostar, resolving the innermost 100 au of a massive protostellar jet for the first time. The morphology of the radio jet emission in this massive object is very different than what is usually observed in jets from low-mass protostars. We found that the outflowing material in HW2 has two components: a wide-angle wind launched from the protostar/disk system, and a highly collimated jet starting at 20–30 au from the protostar. We discuss two possible scenarios: an extension of the classical disk-wind to a massive protostar, or external collimation of a wide-angle wind. These results have important consequences for our understanding of how stars of different masses are formed.

On the Electromagnetic Vacuum Origins of Dark Energy, Dark Matter, and Astrophysical Jets

We use a semiclassical version of the Nexus paradigm of quantum gravity in which the quantum vacuum at large scales is dominated by the second quantized electromagnetic field to demonstrate that a virtual photon field can affect the geometric evolution of Einstein manifolds or Ricci solitons. This phenomenon offers a cogent explanation of the origins of astrophysical jets, the cosmological constant, and a means of detecting galactic dark matter.

Magnetic outflows from turbulent accretion disks

Context. Astrophysical disks are likely embedded in an ambient vertical magnetic field generated by its environment. This ambient field is known to drive magneto-rotational turbulence in the disk bulk, but it is also responsible for launching magnetised outflows at the origin of astrophysical jets. Yet, the interplay between turbulence and outflows is not understood. In particular, the vertical structure and long-term (secular) evolution of such a system lack quantitative predictions. It is, nevertheless, this secular evolution which is proposed to explain time variability in many accreting systems such as FuOr, X-ray binaries, and novae like systems. Aims. We seek to constraint the structure and long-term evolution of turbulent astrophysical disks subject to magnetised outflows in the non-relativistic regime. More specifically we aim to characterise the mechanism driving accretion, the dynamics of the disk atmosphere, the role played by the outflow, and the long-term evolution of mass and magnetic flux distributions. Methods. We computed and analysed global 3D ideal magnetohydrynamic (MHD) simulations of an accretion disk threaded by a large-scale magnetic field. We measured the turbulent state of the system by Reynolds averaging the ideal MHD equations and evaluate the role of the turbulent terms in the equilibrium of the system. We then computed the transport of mass, angular momentum, and magnetic fields in the disk to characterise its secular evolution. Finally, we performed a parameter exploration survey in order to characterise how the transport properties depend on the disk properties. Results. We find that weakly magnetised disks drive jets that carry a small fraction of the disk angular momentum away. The mass-weighted accretion speed remains subsonic, although there is always an upper turbulent atmospheric region where transsonic accretion takes place. We show that this turbulence is driven by a strongly magnetised version of the magneto-rotational instability. The internal disk structure therefore appears drastically different from the conventional hydrostatic picture. We expect that the turbulent atmosphere region will lead to non-thermal features in the emission spectra from compact objects. In addition, we show that the disk is subject to a secular viscous-type instability, which leads to the formation of long-lived ring-like structures in the disk surface density distribution. This instability is likely connected to the magnetic field transport. Finally, we show that for all of the parameters explored, the ambient magnetic field is always dragged inward in the disk at a velocity which increases with the disk magnetisation. Beyond a threshold on the latter, the disk undergoes a profound radial readjustment. It leads to the formation of an inner accretion-ejection region with a supersonic mass-weighted accretion speed and where the magnetic field distribution becomes steady and reaches a magnitude near equipartition with the thermal pressure. This inner structure shares many properties with the jet emitting disk model. Overall, these results pave the way for quantitative self-consistent secular disk models.

Study of Radial Wall Jets from Ceiling Diffusers at Variable Air Volume

The knowledge of the air velocity distribution in the supply jets is essential when designing ventilation and air conditioning systems. In this study, we tested and analyzed the velocity distributions in the radial wall jets—these jets are commonly used in ventilated rooms. Tests included jets from two ceiling diffusers of different constructions, at three airflow rates. The mean air speed distributions were measured with a 16-channel hot-sphere anemometer both in the self-similarity zone and in the terminal zone. A specially developed method of converting the mean speed to mean velocity was used. The measurement results show that the spread coefficients of the jets from both diffusers were the same, but the positions of the virtual origin were different. Due to the friction of the jet with the ceiling and the transfer of momentum to the recirculating flows, the momentum flux in the self-similarity zone decreased by up to 50%. An improved method for calculating velocity distributions in radial wall jets was developed and validated. This method takes into account the decrease of momentum, non-zero position of the jet origin, and faster velocity decrease in the terminal zone. A reliable method of predicting air velocity distribution in radial wall jets (RWJs) from ceiling diffusers may allow to properly select the diffuser size, its location, and the range of flow rate changes. The design process for variable air volume systems can be facilitated.

Probing Jet Launching in Neutron Star X-Ray Binaries: The Variable and Polarized Jet of SAX J1808.4–3658

Abstract We report on an optical photometric and polarimetric campaign on the accreting millisecond X-ray pulsar (AMXP) SAX J1808.4–3658 during its 2019 outburst. The emergence of a low-frequency excess in the spectral energy distribution in the form of a red excess above the disk spectrum (seen most prominently in the z, i, and R bands) is observed as the outburst evolves. This is indicative of optically thin synchrotron emission due to a jet, as seen previously in this source and in other AMXPs during outburst. At the end of the outburst decay, the source enters a reflaring state. The low-frequency excess is still observed during the reflares. Our optical (BVRI) polarimetric campaign shows variable linear polarization (LP) throughout the outburst. We show that this is intrinsic to the source, with low-level but significant detections (0.2%–2%) in all bands. The LP spectrum is red during both the main outburst and the reflaring state, favoring a jet origin for this variable polarization over other interpretations, such as Thomson scattering with free electrons from the disk or the propelled matter. During the reflaring state, a few episodes with stronger LP levels (1%–2%) are observed. The low-level, variable LP is suggestive of strongly tangled magnetic fields near the base of the jet. These results clearly demonstrate how polarimetry is a powerful tool for probing the magnetic field structure in X-ray binary jets, as for active galactic nuclei jets.

Complete theory of the elastic wall jet: A new flow geometry with revisited two-phase nanofluids

In the present research, it is solved in an innovative manner the essentially Non-Similar nanofluids jet discharged over a generalized non-linearly stretching wall. The Non-Similar set-up is interpreted as a combination of wall jet flow at the leading edge and non-linearly stretching sheet flow far away from it. Nanofluids are simulated employing Buongiorno’s two-phase model together with a modified boundary condition for nanoparticles transport equation. The compositely-transformed partial differential equations (PDE) of Non-Similar forms were solved numerically after employing a new mapping function to abridge the horizontal coordinate of an infinite length into a finite one. The numerical algorithm contains quasi-linearization technique together with an implicit algorithm of tridiagonal form. It should be pointed out that such a new Non-Similar setup is brought into account for the first time in the literature. In this respect, we summarize the outstanding novel findings of the present work as: •[I.] Accounting a modified boundary condition for nanoparticles concentration at the wall, the so-called and widely-used Brownian motion parameter, namely Nb, will have absolutely NO impact on Nusselt number or more precisely, on Energy Equation. In this respect, it is presented a new way of defining dimensionless variables.•[II.] As the stretching ratio increases, it is observed a discrepancy in boundary layer thickness; it expands close to the jet area, shrinks in the transition region and adapts the far-field condition, either by expanding or shrinking, depending on the stretching ratio.•[III.] As the stretching ratio increases, Nusselt number decreases slightly shortly after the jet origin and then increases dramatically to match the stretching region.•[IV.] As the stretching ratio increases, nanoparticles at the wall become more concentrated at the downstream and hence, close to the jet region as well as the transition region, the concentration is sparse.•[V.] As thermophoresis parameter, namely Nt, increases, convective heat transfer coefficient drops non-uniformly, from the leading edge to downstream, as well as nanoparticles concentration at the wall.•[V1.] As Schmidt number increases, convective heat transfer drops; however, nanoparticles concentration at the wall increases over the entire spatial domain.

Improved Delineation of Cardiac Pathology Using a Novel Three-Dimensional Echocardiographic Tissue Transparency Tool

Accurate visualization of cardiac valves and lesions by three-dimensional (3D) echocardiography is integral for optimal guidance of structural procedures and appropriate selection of closure devices. A new 3D rendering tool known as transillumination (TI), which integrates a virtual light source into the data set, was recently reported to effectively enhance depth perception and orifice definition. We hypothesized that adding the ability to adjust transparency to this tool would result in improved visualization and delineation of anatomy and pathology and improved localization of regurgitant jets compared with TI without transparency and standard 3D rendering. We prospectively studied 30 patients with a spectrum of structural heart disease who underwent 3D transesophageal imaging (EPIQ system, Philips) with standard acquisition and TI with and without the transparency feature. Six experienced cardiologists and sonographers were shown randomized images of all three display types in a blinded fashion. Each image was scored independently by all experts using a Likert scale from 1 to 5, while assessing each of the following aspects: (1) ability to recognize anatomy, (2) ability to identify pathology, including regurgitant jet origin, (3) depth perception, and (4) quality of border delineation. TI images with transparency were successfully obtained in all cases. All experts perceived an incremental value of the transparency mode, compared with TI without transparency and standard 3D rendering, in terms of ability to recognize anatomy (respective scores: 4.5±1.1 vs 4.1±1.1 vs 3.6±1.1, P<.05), ability to identify pathology (4.1±1.1 vs 3.9±1.2 vs 3.3±1, P<.05), depth perception (4.6±0.7 vs 4.1±0.8 vs 3.2±1.0, P<.05), and border delineation (4.6±0.8 vs 4.1±1.0 vs 3.1±1.1, P<.05). The addition of the transparency mode to TI rendering significantly improves the diagnostic and clinical utility of 3D echocardiography and has the potential to markedly enhance echocardiographic guidance of cardiac structural interventions.

COMPARISON BETWEEN MITRAL CLIP THERAPY AND SURGICAL REPAIR OF MITRAL REGURGITATION IN PATIENTS WITH LEFT VENTRICULAR DYSFUNCTION

Background: Mitral-valve repair can be accomplished with a procedure that involves the percutaneous implantation of a clip that grasps and approximates the edges of the mitral leaflets at the origin of the regurgitate jet. Objective: Our study was performed to compare surgical repair and mitral clip repair for severe secondary MR after failure of maximum medical treatment. Patients and methods: We none randomly were sixty patients with moderately severe or severe (grade 3+ or 4+) mitral regurgitation, 30 patients underwent percutaneous repair by clip and 30 patients underwent conventional surgery for repair of the mitral valve. The primary composite end point for efficacy was freedom from death, required surgery for mitral valve dysfunction (stenosis or regurgitation), and absence of significant MR (grade 3+ or 4+) at 6 months follow up. Results: At 6 months, the rates of the primary end point for efficacy were 79% in the percutaneous repair group and 60% in the surgery group (P = 0.020). The respective rates of the components of the primary end point were as follows: death, 6.9%versus 25%, required surgery for mitral-valve dysfunction, 6.9% versus 10.7%; and significant MR, 16% versus 33%. Major adverse events occurred in 20% of patients in the percutaneous-repair group and 50% of patients in the surgery group at 30 days (P<0.001). Conclusions: Percutaneous treatment was associated with increased safety, improved left ventricular volumes, clinical improvements in NYHA classes and quality of life.

The origin of plasma jets generated in Z-pinch discharges

The results of modeling in the framework of magnetic hydrodynamics (MHD) for the development of a plasma jet in Z-pinches are presented. It has been shown that plasma jet origin is associated with the development of MHD instability m = 0, but not with the conical current sheath structure. MHD modeling is also carried out for θ-pinch systems where generation of plasma jets is much less effective. The corresponding analysis is presented.

Fast inference of Boosted Decision Trees in FPGAs for particle physics

We describe the implementation of Boosted Decision Trees in the hls4ml library, which allows the translation of a trained model into FPGA firmware through an automated conversion process. Thanks to its fully on-chip implementation, hls4ml performs inference of Boosted Decision Tree models with extremely low latency. With a typical latency less than 100 ns, this solution is suitable for FPGA-based real-time processing, such as in the Level-1 Trigger system of a collider experiment. These developments open up prospects for physicists to deploy BDTs in FPGAs for identifying the origin of jets, better reconstructing the energies of muons, and enabling better selection of rare signal processes.