Edge Of Disk Research Articles

Optical Quenching of Magnetic Vortex Visualized In Situ by Lorentz Electron Microscopy

Understanding the fundamental dynamics of topological vortex and antivortex naturally formed in micro/nanoscale ferromagnetic building blocks under external perturbations is crucial to magnetic vortex based information processing and spintronic devices. All previous studies have focused on magnetic vortex-core switching via external magnetic fields, spin-polarized currents, or spin waves, which have largely prohibited the investigation of novel spin configurations that could emerge from the ground states in ferromagnetic disks and their underlying dynamics. Here, we report in situ visualization of femtosecond laser quenching induced magnetic vortex change in various symmetric ferromagnetic Permalloy disks by Lorentz phase imaging using 4D electron microscopy. Besides the switching of magnetic vortex chirality and polarity, we observed with distinct occurrence frequencies a plenitude of complex magnetic structures that have never been observed by magnetic field or current assisted switching. These complex magnetic structures consist of a number of newly created topological magnetic defects (vortex and antivortex) strictly conserving the topological winding number, demonstrating the direct impact of topological invariant on the magnetization dynamics in ferromagnetic disks. Their spin configurations show mirror or rotation symmetry due to the geometrical confinement of the disks. Combined micromagnetic simulations with the experimental observations reveal the underlying magnetization dynamics and formation mechanism of the optical quenching induced complex magnetic structures. Their distinct occurrence rates are pertinent to their formation-growth energetics and pinning effects at the disk edge. Based on these findings, we propose a paradigm of optical-quenching-assisted fast switching of vortex cores for the control of magnetic vortex based information recording and spintronic devices.

Dark Memories of the Past: Discovery of Ultra-Diffuse Objects around NGC 1068

AbstractWe have searched for a sign of the past dynamical disturbance events on NGC 1068, an archetypical Type-2 Seyfert galaxy, using deep and wide optical imaging data by the Subaru telescope. The data taken by Hyper Suprime-Cam (HSC) as well as the archived data by Suprime-Cam reveal several faint outer structures of the galaxy, most of which were never reported before. We discover three large (re = 3 -5.5 kpc), extremely diffuse objects (UDOs) within 45 kpc from the center of NGC 1068. We suggest that two of these UDOs are actually a part of a large loop-like structure surrounding NGC 1068. Such an extremely faint loop or stream is the direct evidence for a past minor merger event. The third UDO has a distorted morphology, suggesting that it is under the influence of strong tidal field. Furthermore, we have identified another ultra-diffuse but compact (μ0,r > 25 mag arcsec-2, re ~ 0.8kpc) dwarf galaxy within ~140 kpc from NGC 1068. We speculate that this ultra-diffuse dwarf could be the object related to the ancient tidal disruption event (tidal dwarf) during the early mass assembly period of NGC 1068. We also detect an asymmetric outer one-arm structure emanated from the western edge of the outermost disk of NGC 1068 together with a ripple-like structure at the opposite side. These structures are also expected to arise in a late phase (up to several billion years ago) of a minor merger, according to numerical simulations. Our findings are consistent with the idea that the AGN activity in NGC 1068 is caused by a past minor merger.

On the nature of the 35-day cycle in the X-ray binary Her X-1/HZ Her

AbstractThe X-ray binary Her X-1 consists of an accreting neutron star and the optical companion HZ Her. The 35-day X-ray variability of this system is known since its discovery in 1972 by the UHURU satellite and is believed to be caused by forced precession of the warped accretion disk tilted to the orbital plane. We argue that the observed features of the optical variability of HZ Her can be explained by free precession of the neutron star with a period close to that of the forced disk precession. The model parameters include a) the intensity (power) of the stream of matter flowing out of the optical star; b) the X-ray luminosity of the neutron star; c) the optical flux of the accretion disk; d) the X-ray irradiation pattern on the donor star; e) the tilt of the inner and outer edge of the accretion disk. A possible synchronization mechanism based on the coupling between the neutron star free precession and the dynamical action of non-stationary gas streams is discussed shortly.

High early solar activity inferred from helium and neon excesses in the oldest meteorite inclusions

Astronomical observations show that early in their evolution, stars experience stages of high activity associated with enhanced energetic particle fluxes1. The Sun’s early activity is often inferred from the spallogenic isotope record (for example, 10Be) in the Solar System’s oldest materials2, calcium–aluminium-rich inclusions (CAIs) in meteorites3,4. However, the 10Be record could be affected by processes other than in situ irradiation by solar particles5. Noble gases can give less ambiguous insights because they are inert volatiles and hence not incorporated into CAIs during their formation6. Here we show that hibonite-rich CAIs, considered to have formed before 26Al-rich CAIs7,8, contain helium and neon excesses that can be unambiguously attributed to in situ irradiation by energetic particles. Given their volatile nature, we infer that the noble gases were produced by irradiation in a relatively cold region at a considerable distance from the Sun (not at the inner disk edge), requiring high particle fluxes and thus high early solar activity. Because more evolved CAIs lack comparable noble gas irradiation records9, we conclude that the oldest Solar System materials experienced a phase of intense irradiation not recorded by materials that formed later. Consequently, disk properties or energetic particle fluxes changed significantly during the very early phases of Solar System evolution. Noble gas abundances measured in the oldest calcium–aluminium-rich inclusions (CAIs) reveal a burst of intense solar irradiation early in the Solar System’s history, not recorded by CAIs that formed later. This result is consistent with a T Tauri phase for the Sun.

Numerical simulation of solid-liquid two phase flow on a rotating disk

Currently, sediment abrasion is becoming more and more serious in hydraulic machinery. In this paper, the internal flow field of solid-liquid two phase was analyzed. In order to improve the uniformity of solid distribution on the surface of rotating disk, the solid particle diameter and inlet concentration need be reduced. With the increasing of the particle diameter and concentration, the difference of solid volume fraction increases between the rotation center and edge of disk. Particles’ velocity of impact the disk’s surface linearly increases along the increasing disk radius. The impact velocity at the outer edge of the disk is maximal, reaching over 40m/s. The change of impact velocity at each radius is not obvious with the variety of particle diameter.

Thick turbulent gas disks with magnetocentrifugal winds in active galactic nuclei

Infrared high-resolution imaging and interferometry show that the dust distribution is frequently elongated along the polar direction of an AGN. In addition, interferometric mm line observations have revealed a bipolar outflow in a direction nearly perpendicular to the nuclear disk. To explain these findings, we developed a model scenario for the inner ~30 pc of an AGN. The structure of the gas within this region is entirely determined by the gas inflow from larger scales. We assumed a rotating thick gas disk between about one and ten parsec. External gas accretion adds mass and injects energy via gas compression into this gas disk and drives turbulence. We extended the description of a massive turbulent thick gas disk developed in a recent paper by adding a magnetocentrifugal wind. Our disks are assumed to be strongly magnetized via equipartition between the turbulent gas pressure and the energy density of the magnetic field. In a second step, we built 3D density cubes based on the analytical model, illuminated them with a central source, and made radiative transfer calculations. In a third step, we calculated mid-infrared (MIR) visibility amplitudes and compared them to available interferometric observations. We show that magnetocentrifugal winds starting from a thin and thick gas disk are viable in active galaxy centers. The magnetic field associated with this thick gas disk plays a major role in driving a magnetocentrifugal wind at a distance of ~1 pc from the central black hole. Once the wind is launched, it is responsible for the transport of angular momentum and the gas disk can become thin. A magnetocentrifugal wind is also expected above the thin magnetized gas disk. The structure and outflow rate of this wind is determined by the properties of the thick gas disk. The outflow scenario can account for the elongated dust structures, outer edges of the thin maser disks, and molecular outflows observed in local AGN. The models reproduce the observed terminal wind velocities, the scatter of the MIR – intrinsic X-ray correlation, and point source fractions. An application of the model to the Circinus galaxy and NGC 1068 shows that the infrared spectral energy distribution, available MIR interferometric observations, and optical polarization can be reproduced in a satisfactory way, provided that (i) a puff-up at the inner edge of the thin disk is present and (ii) a local screen with an optical depth of τV ~ 20 in form of a local gas filament and/or a warp of the thick disk hide a significant fraction of both nuclei. Our thick disk, wind, thin disk model is thus a promising scenario for local Seyfert galaxies.

The Eccentric Cavity, Triple Rings, Two-armed Spirals, and Double Clumps of the MWC 758 Disk

Abstract Spatially resolved structures in protoplanetary disks hint at unseen planets. Previous imaging observations of the transitional disk around MWC 758 revealed an inner cavity, a ring-like outer disk, emission clumps, and spiral arms, all possibly generated by companions. We present ALMA dust continuum observations of MWC 758 at 0.87 mm wavelength with 43 × 39 mas angular resolution (6.9 × 6.2 au) and 20 μJy beam−1 rms. The central submillimeter emission cavity is revealed to be eccentric; once deprojected, its outer edge can be well fitted by an ellipse with an eccentricity of 0.1 and one focus on the star. The broad ring-like outer disk is resolved into three narrow rings with two gaps in between. The outer two rings tentatively show the same eccentricity and orientation as the innermost ring bounding the inner cavity. The two previously known dust emission clumps are resolved in both the radial and azimuthal directions, with radial widths equal to ∼4× the local scale height. Only one of the two spiral arms previously imaged in near-infrared (NIR) scattered light is revealed in ALMA dust emission, at a slightly larger stellocentric distance owing to projection effects. We also submit evidence of disk truncation at ∼100 au based on comparing NIR imaging observations with models. The spirals, the north clump, and the truncated disk edge are all broadly consistent with the presence of one companion exterior to the spirals at roughly 100 au.

Tertiary structure of apolipoprotein A-I in nascent high-density lipoproteins

Understanding the function of high-density lipoprotein (HDL) requires detailed knowledge of the structure of its primary protein, apolipoprotein A-I (APOA1). However, APOA1 flexibility and HDL heterogeneity have confounded decades of efforts to determine high-resolution structures and consistent models. Here, molecular dynamics simulations totaling 30 μs on two nascent HDLs, each with 2 APOA1 and either 160 phospholipids and 24 cholesterols or 200 phospholipids and 20 cholesterols, show that residues 1-21 of the N-terminal domains of APOA1 interact via strong salt bridges. Residues 26-43 of one APOA1 in the smaller particle form a hinge on the disc edge, which displaces the C-terminal domain of the other APOA1 to the phospholipid surface. The proposed structures are supported by chemical cross-linking, Rosetta modeling of the N-terminal domain, and analysis of the lipid-free ∆185APOA1 crystal structure. These structures provide a framework for understanding HDL maturation and revise all previous models of nascent HDL.

Inflow-rotor interaction in Tesla disc turbines: Effects of discrete inflows, finite disc thickness, and radial clearance on the fluid dynamics and performance of the turbine

The article establishes the physics of the complex interaction of discrete multiple inflows with the stationary shroud and the rotating channel of a Tesla disc turbine. Using a large number (150) of separate, fully three-dimensional computational fluid dynamic simulations, we demonstrate the (sometimes dramatic) role of four important input parameters, namely the number of nozzles ([Formula: see text]), rotational speed of the discs (Ω), radial clearance between the rotor and the shroud ([Formula: see text]), and disc thickness ( dt), in the fluid dynamics and performance of a Tesla turbine. An increase in [Formula: see text] or [Formula: see text] assists in the attainment of axisymmetric condition at rotor inlet. Ω influences significantly the distribution of radial velocity including the fundamental shape of its z-profile (parabolic, flat or W-shaped). The paper demonstrates the existence of an optimum [Formula: see text] for which the efficiency of the rotor (η) is maximized. Present computational fluid dynamics simulations for many combinations of [Formula: see text] and Ω establish that the η versus Ω curves, for each fixed value of [Formula: see text], are of the shape of an inverted bucket. With increasing [Formula: see text], the operable range of Ω decreases, the buckets become more peaky and the maximum possible η increases substantially (by a factor of 2 in the example calculation shown). The present systematic work thus demonstrates quantitatively, for the first time, that an axisymmetric rotor inflow condition represents the best possible design for the rotor. It is further shown that, as the disc thickness is increased, the efficiency may decrease substantially (even dramatically) and its maxima occur at lower rotational speeds. Chamfering of the disc edge or partial admission decreases the turbine efficiency. Thus, small disc thickness, flat disc edge, full nozzle opening, optimum radial clearance, and inlet condition as close to axisymmetry as is possible are recommended for the design of an efficient Tesla disc turbine.

Kepler K2 observations of the transitional millisecond pulsar PSR J1023+0038

For 80 days in 2017, the Kepler Space Telescope continuously observed the transitional millisecond pulsar system PSR J1023+0038 in its accreting state. We present analyses of the 59 second cadence data, focusing on investigations of the orbital light curve of the irradiated companion star, and of flaring activity in the neutron star's accretion disc. The underlying orbital modulation from the companion star retains a similar amplitude and asymmetric heating profile as seen in previous photometric observations of the system in its radio pulsar state, suggesting that the heating mechanism has not been affected by the state change. We also find tentative evidence that this asymmetry may vary with time. The light curve also exhibits "flickering" activity, evident as short time-scale flux correlations throughout the observations, and periods of rapid mode-switching activity on time scales shorter than the observation cadence. Finally, the system spent 20% of the observations in a flaring state, with the length of these flares varying from 2 minutes up to several hours. The flaring behaviour is consistent with a self-organised criticality mechanism, most likely related to the build up and release of mass at the inner edge of the accretion disc.

Rolling Centrifuge Repulsion Force Spacecraft

A Rolling Centrifugal Repulsion force UFO Introduction: Any object that rolls along a straight line will generate a centrifugal repulsive force that is away from the body being rolled, it is rolling centrifugal repulsive force. Utilizing this phenomenon, rolling the round ring along the edge of the UFO's disk will produce a constant lift, And then use the electric wheel technology to set the ballast rock at the bottom of the UFO to change the position of the ballast stone at the bottom of the chamber. In order to change the position of the center of gravity of the UFO, the purpose of driving the UFO can be achieved. This is a basic scientific research and applied science both the paper, this paper mainly in the previous article subvert the traditional scientific theory of Cao universal repulsion based on the universal gravitation The further research on the rolling condition and the research on the rolling condition of the ring under gravitation are carried out. The principle of the precession in the spin and the reason of precession are deeply studied. At the same time, on the basis of this principle, from the perspective of a chief designer, designed a man-riding centrifugal universal repulsion flying bike, a powered centrifugal universal repulsion flying car and the use of this flying car as a tool for flight Vehicle manned flying on the moon sampling double aircraft, for which the demand for high speed bearing research and design, in order to be used for aircraft supporting high speed bearing design and manufacturing. Here is the simplest language to explain the most complex issues. This is also a kind of learning。

Non-uniform contact characteristics of the friction disc during the initial period of a braking process

To reveal the contact characteristics of the hydraulic brake friction pair during the initial period of braking process and improve its working stability, by using ABAQUS software, we analyzed numerically the contact characteristics of the friction pair, including temperature, contact stress and heat flux variation laws of the contact surface. Theoretical analysis was verified by experiments. The results show that 1) the variations of the circumferential temperature distribution increase at first and then decrease; 2) the maximum value of the contact stress is near the inner edge of the friction disc, from t = 0.15 s the relatively larger contact stresses begin to intersperse on the entire contact surface; 3) heat flux distributions are similar to the temperature distributions; 4) the nonuniformity of the contact characteristics decreases with the increase of the friction disc thickness. It indicates that a friction disc of thickness 6 mm should be selected preferentially in the design of the hydraulic brake.

The late inspiral of supermassive black hole binaries with circumbinary gas discs in the LISA band

We present the results of 2D, moving-mesh, viscous hydrodynamical simulations of an accretion disc around a merging supermassive black hole binary (SMBHB). The simulation is pseudo-Newtonian, with the BHs modeled as point masses with a Paczynski-Wiita potential, and includes viscous heating, shock heating, and radiative cooling. We follow the gravitational inspiral of an equal-mass binary with a component mass M_bh=10^6 M_sun from an initial separation of 60r_g (where r_g=GM_bh/c^2 is the gravitational radius) to the merger. We find that a central, low-density cavity forms around the binary, as in previous work, but that the BHs capture gas from the circumbinary disc and accrete efficiently via their own minidiscs, well after their inspiral outpaces the viscous evolution of the disc. The system remains luminous, displaying strong periodicity at twice the binary orbital frequency throughout the entire inspiral process, all the way to the merger. In the soft X-ray band, the thermal emission is dominated by the inner edge of the circumbinary disc with especially clear periodicity in the early inspiral. By comparison, harder X-ray emission is dominated by the minidiscs, and the light curve is initially more noisy but develops a clear periodicity in the late inspiral stage. This variability pattern should help identify the EM counterparts of SMBHBs detected by the space-based gravitational-wave detector LISA.

Quasi-periodic oscillations and the global modes of relativistic, MHD accretion discs

The high-frequency quasi-periodic oscillations (HFQPOs) that punctuate the light curves of X-ray binary systems present a window onto the intrinsic properties of stellar-mass black holes and hence a testbed for general relativity. One explanation for these features is that relativistic distortion of the accretion disc's differential rotation creates a trapping region in which inertial waves (r-modes) might grow to observable amplitudes. Local analyses, however, predict that large-scale magnetic fields push this trapping region to the inner disc edge, where conditions may be unfavorable for r-mode growth. We revisit this problem from a pseudo-Newtonian but fully global perspective, deriving linearized equations describing a relativistic, magnetized accretion flow, and calculating normal modes with and without vertical density stratification. In an unstratified model, the choice of vertical wavenumber determines the extent to which vertical magnetic fields drive the r-modes toward the inner edge. In a global model fully incorporating density stratification, we confirm that this susceptibility to magnetic fields depends on disc thickness. Our calculations suggest that in thin discs, r-modes may remain independent of the inner disc edge for vertical magnetic fields with plasma betas as low as $\beta\approx 100-300$. We posit that the appearance of r-modes in observations may be more determined by a competition between excitation and damping mechanisms near the ISCO than the modification of the trapping region by magnetic fields.

Discovery of new dipper stars with K2: a window into the inner disc region of T Tauri stars

In recent years a new class of Young Stellar Object has been defined, referred to as dippers, where large transient drops in flux are observed. These dips are too large to be attributed to stellar variability, last from hours to days and can reduce the flux of a star by 10-50\%. This variability has been attributed to occultations by warps or accretion columns near the inner edge of circumstellar disks. Here we present 95 dippers in the Upper Scorpius association and $\rho$ Ophiuchus cloud complex found in K2 Campaign 2 data using supervised machine learning with a Random Forest classifier. We also present 30 YSOs that exhibit brightening events on the order of days, known as bursters. Not all dippers and bursters are known members, but all exhibit infrared excesses and are consistent with belonging to either of the two young star forming regions. We find 21.0 $\pm$ 5.5\% of stars with disks are dippers for both regions combined. Our entire dipper sample consists only of late-type (KM) stars, but we show that biases limit dipper discovery for earlier spectral types. Using the dipper properties as a proxy, we find that the temperature at the inner disk edge is consistent with interferometric results for similar and earlier type stars.

Novel Insights to the Design of Apolipoprotein AI Mimetic Peptides

Peptides mimicking the major protein of high-density lipoprotein, apolipoprotein AI (APOA1), are promising therapeutics for cardiovascular diseases because they impede the development of atherosclerotic lesions. Similar to APOA1, their atheroprotective characteristic is attributed to the ability to form discoidal bilayer when lipid transporters pleat lipids and cholesterols from macrophages, a process called cholesterol efflux. Understanding the structure of nanodiscs generated by APOA1 mimetics is crucial to the rational design of such therapeutics. However, high-density lipoproteins are resistant to traditional high-resolution approaches, such as NMR or X-ray crystallography. Herein, all-atom Molecular Dynamics simulations on Anton-2 supercomputer determine the structure of nanodiscs and contrast behaviors of two peptides that were experimentally shown to be potent and inactive in cholesterol efflux. The peptides are α-helical, amphipathic, have 18 residues, and solely contain Glu, Leu, and Lys. A 3-μs simulation of a nanodisc with potent peptides shows that they migrate from the disc surface to the edge to cover acyl chains of lipids. In contrast to APOA1 which takes a “belt” configuration, the peptides form a “picket-fence” arrangement whereby they orient along the disc normal. Each peptide interacts with its two neighbors through Lys-Glu salt-bridges mostly in an antiparallel fashion, hence a peptide oligomer. A 2-μs simulation of a nanodisc with inactive peptides, in contrast, demonstrates their incapability to stabilize nanodiscs. Starting from an ideal antiparallel picket-fence on the disc edge, the peptides dimerize but dimers migrate from the edge to the surface leaving acyl chains exposed to water. This is due to the repulsion of negatively charged sidechains of adjacent dimers. Therefore, the simulations establish that APOA1 mimetics should oligomerize to effectively promote cholesterol efflux and that their dimerization is necessary but not sufficient. This insight informs the future design of these peptides.

Quasi-periodic Behavior of Mini-disks in Binary Black Holes Approaching Merger

Abstract We present the first magnetohydrodynamic simulation in which a circumbinary disk around a relativistic binary black hole feeds mass to individual accretion disks (“mini-disks”) around each black hole. Mass flow through the accretion streams linking the circumbinary disk to the mini-disks is modulated quasi-periodically by the streams’ interaction with a nonlinear m = 1 density feature, or “lump,” at the inner edge of the circumbinary disk: the stream supplying each mini-disk comes into phase with the lump at a frequency 0.74 times the binary orbital frequency. Because the binary is relativistic, the tidal truncation radii of the mini-disks are not much larger than their innermost stable circular orbits; consequently, the mini-disks’ inflow times are shorter than the conventional estimate and are comparable to the stream modulation period. As a result, the mini-disks are always in inflow disequilibrium, with their masses and spiral density wave structures responding to the stream’s quasi-periodic modulation. The fluctuations in each mini-disk’s mass are so large that as much as 75% of the total mini-disk mass can be contained within a single mini-disk. Such quasi-periodic modulation of the mini-disk structure may introduce distinctive time-dependent features in the binary’s electromagnetic emission.

Analysis of Photometric Observations of the New Cataclysmic Variable ASASSN-13cx

Photometric observations of the variable star ASASSN-13cx acquired in the course of a program of studies of cataclysmic variables and their parameters recently carried out at the Sternberg Astronomical Institute (SAI) are presented. The star was observed with the 50-cm and 60-cm telescopes of the SAI Crimean Astronomical Station and a CCD photometer (similar to 1800 images in the V and Rc filters) during the variable's outburst of August-September 2014 and in a period of quiescence in October-November 2016. The ASASSN-13cx system is confirmed to be a SU UMa variable. Parameters of the system are derived from eight light curves using a "composite" model that takes into account the presence of a hot spot on the lateral surface of the geometrically thick disk and of a region of enhanced energy release near the disk edge, at the base of the gas flow (the so-called "hot line"). Parameters of the system for three light curves during the outburst were obtained in the framework of a "spiral" model that additionally takes into account the presence of geometric perturbations on the accretion-disk surface. The parameters of ASASSN-13cx determined using these models provide good accuracy in reproducing the system's light curves in both states. The basic parameters of the system have been determined for the first time: the component mass ratio q = M (1)/M (2) = 7.0 +/- 0.2, the orbital inclination i = 79.9A degrees-80.1A degrees, the distance between the components' centers of mass a (0) = 0.821(1) R (Ey), and the sizes and temperatures of the stars: R (1) = 0.0124(5)a (0) = 0.0102(4) R (Ey), T (1) = 12 500 +/- 280 K, aEuroR (2)aEuroe = 0.236(4)a (0) = 0.194(3) R (Ey), T (2) = 2550 +/- 400 K, corresponding to M4-9V for the spectral type of the secondary. Parameters of the accretion disk have been derived for both activity states. The mass of matter in the accretion disk increased by almost a factor of two during similar to 400 orbital periods in quiescence.

Interaction of South Asian spices with conventional antibiotics: Implications for antimicrobial resistance for Mycobacterium abscessus and cystic fibrosis.

Antimicrobial resistance (AMR) has rendered certain species of Mycobacterium difficult to treat clinically, particularly, the nontuberculous Mycobacterium, Mycobacterium abscessus. This bacterium is emerging in specific disease populations, including amongst cystic fibrosis (CF) patients, where AMR represent a true treatment dilemma. Therefore, any innovation with traditional antimicrobial compounds in spices, which increases the potency of existing conventional antibiotics should be investigated. M. abscessus isolates (n = 9 multidrug-resistant clinical isolates from CF patients + 1 Reference Strain) were examined for their direct susceptibility to 27 spices, as well as the interactive effect of this spice combination to their susceptibility to amikacin and linezolid antibiotic, with standard disk diffusion assay. Five isolates of M. abscessus (5/10; 50%) failed to grow on the spice enriched medium, which included four clinical isolates and the National Culture Type Collection (NCTC) Reference Strain. Of the remaining five isolates which grew on the spice medium, no cultural phenotypic differences were observed, compared to unsupplemented controls. In the case of both amikacin and linezolid, the zone of inhibition increased with the inclusion of the spices. Initially, all isolates of M. abscessus were fully resistant to linezolid (mean zone of inhibition = 0 mm), and growth was to the edge of the antibiotic disk, whereas when in the presence of spices, large zones of inhibition were observed (mean zone of inhibition = 33.3 mm). With amikacin, the mean zone of inhibition increased from 23.2 mm to 32.0 mm, in the presence of spices. These data suggest that the spices were interacting synergistically with the antibiotics, thus making the antibiotic more potent against the bacteria tested. This study is significant as it demonstrates a positive interaction between spices and the conventional antimycobacterial antibiotics, amikacin, and linezolid. Given the burden of AMR to M. abscessus, particularly in a patient with chronic disease such as CF, any food-related innovation that can help maximize the potency of existing antimycobacterial antibiotics is to be encouraged and developed. The specific mechanism as to how spices increase the potency of such antibiotics with M. abscessus needs to be elucidated, as well as novel food (spice) delivery modalities developed, including novel medicinal foodstuffs or functional foods, that can harness this beneficial effect in vivo to medicine and society.

Determination of the Spins of Supermassive Black Holes in FR I and FR II Radio Galaxies

The spins of supermassive black holes in FR I and FR II radio galaxies are estimated using two models for the generation of the relativisitic jets, based on the Blandford–Znajek and Blandford–Payne mechanisms: the hybrid model of Meier and a flux-trapping model. The magnetic field at the event horizon is estimated assuming equipartition between the energy densities of the magnetic field and the accreting material. The magnetic field near the inner edge of the accretion disk is estimated assuming equipartition between the magnetic pressure and the radiation pressure, and also assuming proportionality between the magnetic field and the spin. In the case of FR I objects, both mechanisms for the generation of the jets (the hybrid model of Meier and a flux-trapping model) are efficient. For the FR II objects, equipartition between the energy densities of the magnetic field and the accretion flow facilitates stronger retrograde rotation of the supermassive black hole. Plots of spin versus mass suggest a predominantly chaotic character for the accretion in both types of radio galaxies.