Femoral vectoring for hip dysplasia in neonates

The biomechanical factors influencing the reduction of dislocated hips with the Pavlik harness in patients of developmental hip dysplasia (DDH) were studied and simulated using a three-dimensional Finite Element Method (FEM) computer model. We identified five hip adductor muscles as key mediators in the prognosis of reduction for DDH, and determined the non-dimensional force contribution of each muscle in the direction necessary to achieve hip reduction for subluxated and fully dislocated hip joints. Results indicate that the effects of the muscles studied are functions of the severity of DDH. For an abducted and flexed subluxated hip, the Pectineus, Adductor Brevis, proximal Adductor Magnus, and Adductor Longus muscles aid reduction, while the portions of the Adductor Magnus muscle with middle and distal femoral insertion contribute negatively. For a fully dislocated hip all muscles contribute detrimentally. Consequently, our study points at the adductor muscles as the mediators of reductions of subluxated hips, and suggests the need for external traction to bring fully dislocated hips over the posterior acetabulum and labrum. Additionally, the reduction process of dysplastic hips was found to occur in two phases: (1) Release phase and (2) Reduction phase, and the muscles studied act distinctively in each phase. Moreover, we performed a cadaveric dissection to study the 3-dimensional orientation of the iliopsoas tendon in different hip configurations, and found that in hip abduction and flexion this tendon is likely not an obstruction to DDH reductions. We also report on the development of an improved three-dimensional anatomical computer model of the hip and femora of a 10-week old female infant for further study of hip dysplasia and other conditions of the hip using dynamic simulations and the Finite Element Method. This model was generated by combining CT-scans from four human subjects, as well as muscle positional data. It was segmented to encompass the distinct cartilaginous regions of infant anatomy, as well as the different regions of cortical and cancellous bone; these properties were retrieved from the literature. This engineering computer model of an infant anatomy is being employed f or ( 1) t he development of an anatomy-based finite element and dynamics computer model for simulations of hip dysplasia reductions using novel treatment approaches, (2) the determination of a path of least resistance in reductions of hip dysplasia based on a minimum potential energy approach, (3) the study of the mechanics of hyperflexion of the hip as alternative treatment for late-presenting cases of hip dysplasia, and (4) a comprehensive investigation of the effects of femoral anteversion angle (AV) variations in reductions of hip dysplasia. This study thus reports on an interdisciplinary effort between orthopedic surgeons and mechanical engineers to apply engineering fundamentals to solve medical problems. The results of this research are clinically relevant in pediatric orthopaedics

Bonn Potential and Shell-Model Calculations for 206,205,204Pb

The structure of the nuclei 206,205,204Pb is studied interms of shell model employing a realistic effective interaction derived from the Bonn A nucleon-nucleon potential. The energy spectra, binding energies and electromagnetic properties are calculated and compared with experiment. A very good overall agreement is obtained. This evidences the reliability of our realistic effective interaction and encourages use of modern realistic potentials in shell-model calculations for heavy-mass nuclei.Comment: 4 pages, 4 figures, submitted to Physical Review

Interpreting molecular hydrogen and atomic oxygen line emission of T Tauri disks with photoevaporative disk-wind models

Context. Winds in protoplanetary disks play an important role in their evolution and dispersal. However, the physical process that is actually driving the winds is still unclear (i.e. magnetically versus thermally driven), and can only be understood by directly confronting theoretical models with observational data. Aims. We aim to interpret observational data for molecular hydrogen and atomic oxygen lines that show kinematic disk-wind signatures in order to investigate whether or not purely thermally driven winds are consistent with the data. Methods. We use hydrodynamic photoevaporative disk-wind models and post-process them with a thermochemical model to produce synthetic observables for the spectral lines o-H2 1-0 S(1) at 2.12 μm and [OI] 1D2-3P2 at 0.63 μm and directly compare the results to a sample of observations. Results. We find that our photoevaporative disk-wind model is consistent with the observed signatures of the blueshifted narrow low-velocity component (NLVC) -which is usually associated with slow disk winds -for both tracers. Only for one out of seven targets that show blueshifted NLVCs does the photoevaporative model fail to explain the observed line kinematics. Our results also indicate that interpreting spectral line profiles using simple methods, such as the thin-disk approximation, to determine the line emitting region is not appropriate for the majority of cases and can yield misleading conclusions. This is due to the complexity of the line excitation, wind dynamics, and the impact of the actual physical location of the line-emitting regions on the line profiles. Conclusions. The photoevaporative disk-wind models are largely consistent with the studied observational data set, but it is not possible to clearly discriminate between different wind-driving mechanisms. Further improvements to the models are necessary, such as consistent modelling of the dynamics and chemistry, and detailed modelling of individual targets (i.e. disk structure) would be beneficial. Furthermore, a direct comparison of magnetically driven disk-wind models to the observational data set is necessary in order to determine whether or not spatially unresolved observations of multiple wind tracers are sufficient to discriminate between theoretical models

The Adiabatic Transport of Bose-Einstein Condensates in a Double-Well Trap: Case a Small Nonlinearity

A complete adiabatic transport of Bose-Einstein condensate in a double-well trap is investigated within the Landau-Zener (LZ) and Gaussian Landau-Zener (GLZ) schemes for the case of a small nonlinearity, when the atomic interaction is weaker than the coupling. The schemes use the constant (LZ) and time-dependent Gaussian (GLZ) couplings. The mean field calculations show that LZ and GLZ suggest essentially different transport dynamics. Significant deviations from the case of a strong coupling are discussed.Comment: 6 pages, 3 figures, to be published in Laser Physic

Tunneling dynamics in exactly-solvable models with triple-well potentials

Inspired by new trends in atomtronics, cold atoms devices and Bose-Einstein condensate dynamics, we apply a general technique of N=4 extended Supersymmetric Quantum Mechanics to isospectral Hamiltonians with triple-well potentials, i.e. symmetric and asymmetric. Expressions of quantum-mechanical propagators, which take into account all states of the spectrum, are obtained, within the N = 4 SQM approach, in the closed form. For the initial Hamiltonian of a harmonic oscillator, we obtain the explicit expressions of potentials, wavefunctions and propagators. The obtained results are applied to tunneling dynamics of localized states in triple-well potentials and for studying its features. In particular, we observe a Josephson-type tunneling transition of a wave packet, the effect of its partial trapping and a non-monotonic dependence of tunneling dynamics on the shape of a three-well potential. We investigate, among others, the possibility of controlling tunneling transport by changing parameters of the central well, and we briefly discuss potential applications of this aspect to atomtronic devices.Comment: Latex, 28 pages, 7 Figs, 2 Tables; minor presentation changes, journal versio

Disk Evolution Study Through Imaging of Nearby Young Stars (DESTINYS): Scattered light detection of a possible disk wind in RY Tau

Disk winds are an important mechanism for accretion and disk evolution around young stars. The accreting intermediate-mass T-Tauri star RY Tau has an active jet and a previously known disk wind. Archival optical and new near-infrared observations of the RY Tau system show two horn-like components stretching out as a cone from RY Tau. Scattered light from the disk around RY Tau is visible in near-infrared but not seen at optical wavelengths. In the near-infrared, dark wedges that separates the horns from the disk, indicating we may see the scattered light from a disk wind. We use archived ALMA and SPHERE/ZIMPOL I-band observations combined with newly acquired SPEHRE/IRDIS H-band observations and available literature to build a simple geometric model of the RY Tau disk and disk wind. We use Monte Carlo radiative transfer modelling \textit{MCMax3D} to create comparable synthetic observations that test the effect of a dusty wind on the optical effect in the observations. We constrain the grain size and dust mass needed in the disk wind to reproduce the effect from the observations. A model geometrically reminiscent of a dusty disk wind with small micron to sub-micron size grains elevated above the disk can reproduce the optical effect seen in the observations. The mass in the obscuring component of the wind has been constrained to $1\times10^{-9} M_{\odot} \leq M \leq 5\times10^{-8} M_{\odot}$ which corresponds to a lower limit mass loss rate in the wind of about $\sim 1\times10^{-8}M_{\odot}\mathrm{yr}^{-1}$. While an illuminate dust cavity cannot be ruled out without measurements of the gas velocity, we argue that a magnetically launched disk wind is the most likely scenario.Comment: 11 pages, 5 figure

Properties of odd nuclei and the impact of time-odd mean fields: A systematic Skyrme-Hartree-Fock analysis

We present a systematic analysis of the description of odd nuclei by the Skyrme-Hartree-Fock approach augmented with pairing in BCS approximation and blocking of the odd nucleon. Current and spin densities in the Skyrme functional produce time-odd mean fields (TOMF) for odd nuclei. Their effect on basic properties (binding energies, odd-even staggering, separation energies and spectra) is investigated for the three Skyrme parameterizations SkI3, SLy6, and SV-bas. About 1300 spherical and axially-deformed odd nuclei with 16 < Z < 92 are considered. The calculations demonstrate that the TOMF effect is generally small, although not fully negligible. The influence of the Skyrme parameterization and the consistency of the calculations are much more important. With a proper choice of the parameterization, a good description of binding energies and their differences is obtained, comparable to that for even nuclei. The description of low-energy excitation spectra of odd nuclei is of varying quality depending on the nucleus

Accuracy and repeatability of wrist joint angles in boxing using an electromagnetic tracking system

© 2019, The Author(s). The hand-wrist region is reported as the most common injury site in boxing. Boxers are at risk due to the amount of wrist motions when impacting training equipment or their opponents, yet we know relatively little about these motions. This paper describes a new method for quantifying wrist motion in boxing using an electromagnetic tracking system. Surrogate testing procedure utilising a polyamide hand and forearm shape, and in vivo testing procedure utilising 29 elite boxers, were used to assess the accuracy and repeatability of the system. 2D kinematic analysis was used to calculate wrist angles using photogrammetry, whilst the data from the electromagnetic tracking system was processed with visual 3D software. The electromagnetic tracking system agreed with the video-based system (paired t tests) in both the surrogate ( 0.9). In the punch testing, for both repeated jab and hook shots, the electromagnetic tracking system showed good reliability (ICCs > 0.8) and substantial reliability (ICCs > 0.6) for flexion–extension and radial-ulnar deviation angles, respectively. The results indicate that wrist kinematics during punching activities can be measured using an electromagnetic tracking system