Multiple Instability Research Articles

Multiple interaction solutions, parameter analysis, chaotic phenomena and modulation instability for a (3+1)-dimensional Kudryashov–Sinelshchikov equation in ideal liquid with gas bubbles

Multiple interaction solutions, parameter analysis, chaotic phenomena and modulation instability for a (3+1)-dimensional Kudryashov–Sinelshchikov equation in ideal liquid with gas bubbles

Inter-ELM pedestal turbulence dynamics dependence on q95 and temperature gradient

A series of dedicated experiments from the DIII-D tokamak provide spatially and temporally resolved measurements of electron density and temperature, and multiscale and multichannel fluctuations over a wide range of conditions. Measurements of long wavelength density fluctuations in the type-I ELMing H-mode pedestals routinely reveal a coexistence of multiple instabilities that exhibit dramatic different dynamic behaviors as q95 and temperature gradients are varied, apparently responsible for limiting pedestal temperature profiles. Two distinct frequency bands of density fluctuations are modulated by an ELM cycle with frequency above 200 kHz propagating in the electron diamagnetic direction in the lab frame (electron mode) and below 200 kHz propagating in the ion diamagnetic direction (ion mode). The electron mode amplitude peaks near the electron temperature gradient region and increases with q95 which seems to be correlated with the increased χe at higher q95, similar to the characteristics expected for the micro-tearing mode (MTM). At higher q95, during the inter-ELM period, the ion mode decays at the later phase of the ELM cycle. Consistently, the poloidal correlation length of the ion mode is also found to reduce, which suggests the possible E × B flow shear suppression of the ion mode at the later phase of the ELM cycle as the Er well recovers. In contrast, the electron mode grows during the ELM cycle and reaches saturation at around 50%–60% of the ELM period. Linear gyrokinetic simulations find the MTMs to be the most unstable mode in the pedestal electron temperature gradient region. The higher q95 and lower magnetic shear destabilize the MTMs. These observations provide key insights into the underlying physics of multifield properties and a rich dataset of experimental ‘fingerprints’ that enable new tests of theoretical pedestal models and lead to the development of a predictive model for pedestal formation on the ITER and future burning plasma experiments.

Hidden Charge Order and Multiple Electronic Instabilities in EuTe4.

The rare-earth telluride compound EuTe4 exhibits a charge density wave (CDW) and an unconventional thermal hysteresis transition. Herein, we report a comprehensive study of the CDW states in EuTe4 by using low-temperature scanning tunneling microscopy. Two types of charge orders are observed at 4 K, including a newly discovered spindle-shaped pattern and a typical stripe-like pattern. As an exotic charge order, the spindle-shaped CDW is off-axis and barely visible at 77 K, indicating that it is a hidden order developed at low temperature. Based on our first-principles calculations, we reveal the origins of the observed electronic instabilities. The spindle-shaped charge order stems from a subsequent transition based on the stripe-like CDW phase. Our work demonstrates that the competition and cooperation between multiple charge orders can generate exotic quantum phases.

The perils of fiscal feedback rules

This paper introduces a fiscal feedback rule (FFR) in an endogenous growth model with public debt dynamics. We assume that part of the debt burden is covered by tax increases (we name this “sterilization”), while the remaining part is financed by issuing new debt. We show that while low sterilization does not ensure the existence of a long-run steady state, high sterilization can lead to multiple steady states and aggregate instability in the form of local and global indeterminacy, potentially condemning the economy to a low-growth/high-debt trap steady state and long-lasting public debt cycles. By combining econometric estimations and a calibration exercise on developed economies, we highlight that these various perils can occur for empirically plausible values of the sterilization coefficient.

Unconventional Polarization Response in Titanite-Type Oxides due to Hashed Antiferroelectric Domains.

Domains in a crystal, which have crystallographic uniformity and are geometrically segmented, typically arise from various phase transitions. The physical properties within individual domains are inherently the same as those in the homogeneous bulk. As a result, sufficiently large domains have little influence on the bulk properties. However, as the domains decrease in size to the nanoscale, for instance, due to multiple phase instabilities or spatial inhomogeneities, then the materials often acquire exceptional functionalities that are unattainable without these domains. This effect is exemplified by the ultrahigh dielectric and piezoelectric responses observed in ferroelectric oxides with nanoscale polar domains as well as in ferroelectric relaxors with polar nanoclusters. Here, we demonstrate that hashed nanoscale domains in an antiferroelectric material are also capable of boosting dielectric permittivity in an unconventional way. This discovery has been made in an antiferroelectric titanite-type oxide, CaTi(Si1-xGex)O5, in which the permittivity significantly increases when the antiferroelectric order becomes short-range. Our transmission electron microscopy observations have clarified that polar regions simultaneously appear around antiphase boundaries in the antiferroelectric phase of CaTi(Si1-xGex)O5. As the concentration of the antiphase boundary increases, the polar regions become denser and play a crucial role in boosting the permittivity. At the composition of x = 0.5, the value of the permittivity finally reaches double that in the bulk and shows excellent linearity, at least until an electric field of 500 kV/cm is applied. The present findings highlight the promise of domain engineering for boosting the permittivity in antiferroelectrics as a way to develop materials with excellent dielectric properties.

Posterior Shoulder Instability, Part II—Glenoid Bone Grafting, Glenoid Osteotomy, and Rehabilitation/Return to Play—An International Expert Delphi Consensus Statement

The purpose of this study was to establish consensus statements on glenoid bone-grafting, glenoid osteotomy, rehabilitation, return to play, and follow-up for posterior shoulder instability. A consensus process on the treatment of posterior shoulder instability was conducted, with 71 shoulder/sports surgeons from 12 countries participating based on their level of expertise in the field. Experts were assigned to one of 6 working groups defined by specific subtopics within posterior shoulder instability. Consensus was defined as achieving 80-89% agreement, whereas strong consensus was defined as 90-99% agreement, and unanimous consensus was indicated by 100% agreement with a proposed statement. All of the statements relating to rehabilitation, return to play, and follow-up achieved consensus. There was unanimous consensus that the following criteria should be considered: restoration of strength, range of motion, proprioception, and sport-specific skills, with a lack of symptoms. There is no minimum time point required to return to play. Collision athletes and military athletes may take longer to return because of their higher risk for recurrent instability, and more caution should be exercised in clearing them to return to play, with elite athletes potentially having different considerations in returning to play. The relative indications for revision surgery are symptomatic apprehension, multiple recurrent instability episodes, further intra-articular pathologies, hardware failure, and pain. The study group achieved strong or unanimous consensus on 59% of statements. Unanimous consensus was reached regarding the criteria for return to play, collision/elite athletes having different considerations in return to play, indications for revision surgery, and imaging only required as routine for those with glenoid bone-grafting/osteotomies at subsequent follow-ups. There was no consensus on optimal fixation method for a glenoid bone-block, the relative indications for glenoid osteotomy, whether fluoroscopy is required or if the labrum should be concomitantly repaired. Level V Expert Opinion.

On the laminar wake of curved plates

Numerical simulations are performed to investigate the effect of the Reynolds number (Re) on flow over curved plates. Concave and convex plates, obtained by introducing curvature on a flat plate, are analyzed in the Reynolds number range 0.1 ≤Re≤ 120. It is observed that for a concave plate, the separation point is dependent on Re, while for a convex plate, the flow separates from the outermost tips for all Reynolds numbers. The analysis of time-averaged quantities reveals that concave and convex plates behave differently for the same Reynolds number. In the steady flow regime, visualization of streamlines reveals the presence of a recirculation bubble on the front side of the concave plate, even for the lowest Reynolds number (Re = 0.1). However, at higher Reynolds numbers (Re = 110, 120), the near wake of concave plate witnesses secondary and tertiary recirculating entities. The present simulations also report the unique phenomenon of vortex realignment and divergence of vortex street in the wake of a concave plate. For a convex plate, the vortex realignment is followed by the movement of upper and lower vortices as two parallel vortex streets. The existence of multiple instabilities is another highlight in the near and far wakes of the concave plate, some of which arise due to the secondary vortex interactions. A comprehensive analysis further reveals a handful of novel phenomenal occurrences in the wake of concave surfaces.

Single-shot fast cinematic imaging during merging process of multiple electron filaments in electrostatic potential well.

For the first time, details of the spatial and temporal acceptable evolution of the merging process of co-rotating electron vortices in a potential well are successfully captured using a "single-shot method" with a high temporal resolution of 10 µs. Four-electron filaments are trapped inside the Beam eXperiment-Upgrade linear trap [H. Himura, Nucl. Instrum. Methods Phys. Res. A 811, 100 (2016)] with a uniform axial magnetic field and co-axial multi-ring electrodes. Images of non-emitting electron filaments are captured using a high-speed camera with up to 1 000 000fps, a microchannel plate, a fast-decay phosphor screen of which fluorescence duration is 0.15 µs, and a super fine metallic mesh with an open area ratio of 89%. Images captured every 10 µs clearly show the growth of multiple short-wave instabilities in the wing trailing electron vortices. The experimental methods and measurement techniques presented in this paper can contribute to revealing exactly how small vortices evolve into a large structure or turbulence in a potential well through complex processes.

A robust route to randomness in a simple Cournot duopoly game where ambiguity aversion meets constant expectations

In this paper we investigate the dynamics of a duopoly game with ambiguity aversion regarding uncertainty in demand and constant expectations concerning competitor production. The focus is on an asymmetric Cournot game where players engage in robust optimization and have different beliefs about the possible realizations of the random parameters of the price function. The players’ ambiguity aversion introduces multiple equilibria and instability that otherwise would not be present. The investigation of the global dynamics of the game reveals the emergence, through border-collision bifurcations, of periodic and chaotic dynamics.

Interaction and breakdown induced by multiple optimal disturbances in hypersonic boundary layer

The present paper finds that the coexistence of multiple primary instability waves may cause a non-trivial nonlinear interaction and breakdown process, which has not been reported before. In the considered Mach 6 flat-plate boundary layer, a global resolvent analysis reports three optimal disturbances (local maxima): a high-frequency planar wave, a low-frequency oblique wave and a stationary streak. For the dominant planar and oblique waves, a parabolised stability equation analysis identifies the initial non-modal transient growth and downstream modal growth. Initiated by these two optimal disturbances jointly, the complete linear and nonlinear instability processes until breakdown to turbulence are shown with direct numerical simulation. Owing to the transient growth, the oblique wave may be more significant than the planar wave in the breakdown. The oblique wave and scales of nonlinear interactions are pronounced in the outer layer, whose significance may not be comprehensively characterised by the wall pressure measurement. Fourier modes characterising the oblique-wave oblique breakdown, the planar-wave fundamental resonance, the planar-wave subharmonic resonance and the combination resonance related to a detuned mode are observed successively. The detuned mode seems to dominate the near-wall dynamics in the late nonlinear stage, characterised by $\varLambda$ -like structures. Meanwhile, the existence of this detuned mode is independent of the initial amplitude ratio and the absolute amplitude of the oblique and planar waves. Weakly nonlinear stability analyses demonstrate that the detuned mode is mainly a consequence of the secondary instability under the combination of planar and oblique primary waves. Wave vector plots reveal the resonant state of multiple triads. Energy budget and amplitude-correction analyses provide a clear physical image of energy transfer.

A Multiple-Burner Approach to Passive Control of Multiple Longitudinal Acoustic Instabilities in Combustors

Abstract Presently, passive methods of controlling combustion instability fall short when one considers stabilizing multiple acoustic modes. In this paper, we present a passive control approach based on the locations of the burners to stabilize multiple acoustic modes. The approach is demonstrated using linear stability analysis performed on a canonical open–open rectangular tube enclosing a flame. A linear flame model based on the kinematic description of the flame surface is used. A simultaneous solution method, as opposed to a segregated method, is developed to calculate the mean flow and to evaluate mode shapes and eigenvalues. The stability analysis is performed both on single and on multiple-burner combustors. In the latter case, the axial and transversal arrangement of burners considered preserves the net volumetric heat release rate and exit temperature. The problem of stabilizing the first three acoustic modes is cast as a multi-objective optimization problem for both types of combustors using the location(s) of the burner(s) as decision variable(s). We show that the use of multiple burners markedly increases the stability of the first three modes while not disturbing the combustor design parameters.

Patellar Dislocation: Workup and Decision-Making.

Acute patellar dislocation (PD) is usually a problem of adolescents and young adults. In most cases, it is a sports-related injury. It is the result of an indirect force on the knee joint, which leads to valgus and external rotation of the tibia relative to the femur. PD is unlikely to occur on a knee with normal patellofemoral joint (PFJ) anatomy. Acute PD consists of an acute injury of the ligamentous medial patellar stabilizers in the background of factors predisposing to patellar instability. These factors are classified into three groups. The first group refers to the integrity of the ligamentous medial patellar restraints, particularly, the medial patellofemoral ligament (MPFL). The second group refers to an abnormal PFJ anatomy, which renders the patella inherently unstable inside the trochlea. The third group refers to the overall axial and torsional profile of the lower limb and to systemic factors, such as ligament laxity and neuromuscular coordination of movement. PD at a younger age is associated with an increased number and severity of patellar instability predisposing factors and lower stress to dislocate the patella. Acute primary PD is usually treated conservatively, while surgical treatment is reserved for recurrent PD. The aim of treatment is to restore the stability and function of the PFJ and to reduce the risk of patellar redislocation. Surgical procedures to treat patellar instability are classified into non-anatomic and anatomic procedures. Non-anatomic procedures are extensor mechanism realignment techniques that aim to center the patella into the trochlear groove. Anatomic procedures aim to restore the PFJ anatomy (ruptured ligaments, osteochondral fractures), which has been severed after the first incident of PD. Anatomic procedures, especially MPFL reconstruction, are more effective in preventing recurrent PD, compared with non-anatomic techniques. Theoretically, all factors that affect PFJ stability should be evaluated and, if possible, addressed. This is practically impossible. Considering that the MPFL ruptures in almost all PDs, MPFL reconstruction is the primary procedure, which is currently selected by most surgeons as a first-line treatment for patients with recurrent PD. Restoration of the axial and torsional alignment of the lower limbs is also increasingly implemented by surgeons. Non-anatomic surgical techniques, such as tibial-tuberosity osteotomy, are used as an adjunct to anatomic procedures. In the presence of multiple PFJ instability factors, acute MPFL reconstruction may be the treatment of choice for acute primary PD as well. Skeletal immaturity of the patient precludes osseous procedures to avoid premature physis closure and subsequent limb deformity. Unfortunately, restoration of the patient's previous activity level or participation in more strenuous sports is questionable and not easy to predict. In the case of competitive athletes, PD may prevent participation in elite levels of sports.

Shape and diffusion instabilities of two non-spherical gas bubbles under ultrasonic conditions

Ultrasonic cavitation involves dynamic oscillation processes induced by small bubbles in a liquid under the influence of ultrasonic waves. This study focuses on the investigation of shape and diffusion instabilities of two bubbles formed during cavitation. The derived equations for two non-spherical gas bubbles, based on perturbation theory and the Bernoulli equation, enable the analysis of their shape instability. Numerical simulations, utilizing the modified Keller–Miksis equation, are performed to examine the shape and diffusion instabilities. Three types of shape instabilities, namely, Rayleigh–Taylor, Rebound, and parametric instabilities, are observed. The results highlight the influence of initial radius, distance, and perturbation parameter on the shape and diffusion instabilities, as evidenced by the R 0–P a phase diagram and the variation pattern of the equilibrium curve. This research contributes to the understanding of multiple bubble instability characteristics, which has important theoretical implications for future research in the field. Specifically, it underscores the significance of initial bubble parameters, driving pressure, and relative gas concentration in determining the shape and diffusive equilibrium instabilities of non-spherical bubbles.

Machine learning‐based predictions of buckling behaviour of cold‐formed steel structural elements

AbstractDesigning thin‐walled structural members is a complex process due to the possibility of multiple instabilities. This study aimed to develop machine learning algorithms to predict the buckling behavior of thin‐walled channel elements under axial compression or bending. The algorithms were trained using feed‐forward multi‐layer Artificial Neural Networks (ANNs), with the input variables including the cross‐sectional dimensions, the thickness, the presence and location of intermediate stiffeners, and the element length. The output data included the elastic critical buckling load or moment, as well as a modal decomposition of the buckled shape into the pure buckling mode categories: local, distortional and global buckling. The Finite Strip Method (FSM) and the Equivalent Nodal Force Method (ENFM) were used to prepare the sample output for training. To ensure the accuracy of the developed algorithms, the ANN models were subjected to a K‐fold cross‐validation technique and featured optimized hyperparameters. The results showed that the trained algorithms had a remarkable accuracy of 98% in predicting the elastic critical buckling loads and modal decomposition of the critical buckled shapes.

Simultaneous Observation of Whistler‐Mode Chorus and Fast Magnetosonic Waves During the Magnetic Peak in the Inner Magnetosphere

AbstractSimultaneous observations of whistler‐mode chorus and magnetosonic (MS) waves are reported within a magnetic peak in the inner magnetosphere for the first time. During the magnetic peak, Van Allen Probe A observes flux enhancements of both ring current electrons and relativistic electrons, while medium‐energy proton fluxes are reduced but high‐energy proton fluxes are raised. Those flux variations of ring current particles are almost concentrated in the perpendicular direction of the background magnetic field, leading to enhancements of the electron temperature anisotropy and a positive gradient of proton velocity distributions. The calculated linear growth rates show that unstable electrons with temperature anisotropic instabilities and unstable protons with ring distribution during the magnetic peak structure can provide free energy for the excitation of whistler‐mode chorus and MS waves, respectively. Our findings suggest that injected particles encountering the magnetic peak structure may form more complex unstable electron and ion distributions driving multiple instabilities simultaneously.

Fiscal expansion, government debt and economic growth: a post-Keynesian perspective

Constructing a post-Keynesian macro-model, we investigate the impact of fiscal expansion on aggregate demand and economic growth, explore public debt sustainability, and analyze whether fiscal policy plays any role in stabilizing the economy. We explore how the interaction between capital accumulation and government debt opens the possibility of multiple equilibria and instability in the economy. We investigate the impact of various parameters on short-run aggregate demand and long-run equilibrium growth rate, and public debt-capital ratio. We explore the relationship between a progressive tax system and a wage-led demand regime. In some cases, a sufficiently high government expenditure to GDP ratio is essential for achieving stability in the system. A sufficiently high government expenditure to GDP ratio ensures economic stability in other circumstances. The possibility of the limit cycle is also explored. Higher autonomous investment demand is desirable as it enhances the stable region of the economy.

Comprehensive ctDNA analysis to identify genome-instability and actionable mutation landscape in gynecologic cancers.

e17503 Background: Gynaecology malignancies are the second most prevalent cancers in women worldwide with rapid progression, high relapse, and mortality. Although HRR pathway inhibitors can greatly benefit clinical outcomes, patients without HRR pathway mutations may remain unbenefited while being profiled for tissue DNA or with a small target gene panel. Compelling data suggest that plasma genotyping shows a wide diversity of cancer mutations along genome instability indicators compared to tumor tissue. Here, we analyzed the mutational landscape of ctDNA and tissue DNA (tDNA) obtained from gynecologic cancer patients. We demonstrate the clinical utility of a comprehensive gene panel to identify multiple actionable mutations and genome instability indicators from ctDNA samples. Methods: We retrospectively analyzed the mutational landscape of 22 ovarian and endometrial cancer patients using target-hybridization enrichment of ctDNA and tDNA. Libraries prepared using a custom-designed comprehensive gene panel OncoIndx, targeting 600 cancer-relevant exons including MSI and HRR pathway genes, were sequenced on the Illumina NGS platform in pair-end mode. Variant calling was performed with an in-house developed bioinformatics pipeline. Results: NGS analysis revealed a total of 127 mutations consisting SNVs (45.6 %), truncations (40.94 %), amplifications (4.72 %), splice variants (4.72 %), and frameshift (3.94 %). Genome-wide mutational analysis showed a slightly higher mean TMB (15.7) for endometrial tumors compared to ovarian samples (11.85). The mean HRD score (45 %) was high for 90 % of patients and corroborated well with the HRR pathway gene mutation. 30 % of patients without HRR gene mutations including BRCA 1/2 had a high average HRD score (43 %) (LOH/TAI/LST) and may qualify for PARP inhibitors (PARPi). Alterations in Ras isoforms (H, K, and N) were the most frequent (36 %) followed by TP53 and PI3K (32 %). At the pathway level, DDR gene-variants were most frequently followed by alterations in proliferative signaling genes. ctDNA showed a wider mutational landscape, including clinically significant mutations, compared to tDNA. Additionally, ctDNA analysis revealed the presence of novel variants of SUFU and KIT, which remain unexplored in the context of cancer stem cells and relapse. Conclusions: Comprehensive mutational landscape showed the presence of genome-wide instability and the presence of mutations in the HRR pathway. Our results suggest that patients with high HRD scores and Ras pathway instability may benefit from Ras pathway inhibitors-PARPi combination. Mutational landscapes obtained from ctDNA were significantly wider and revealed multiple actionable targets compared to tDNA suggesting ctDNA as a viable and informative alternative for genotyping of gynecological cancers.

Impact of Sb degrees of freedom on the charge density wave phase diagram of the kagome metal CsV3Sb5

Elucidating the microscopic mechanisms responsible for the charge density wave (CDW) instability of the AV$_3$Sb$_5$ (A=Cs, K, Rb) family of kagome metals is critical for understanding their unique properties, including superconductivity. In these compounds, distinct CDW phases with wave-vectors at the $M$ and $L$ points are energetically favorable, opening the possibility of tuning the type of CDW order by appropriate external parameters. Here, we shed light on the CDW landscape of CsV$_3$Sb$_5$ via a combination of first-principles calculations and phenomenology, which consists of extracting the coefficients of the CDW Landau free-energy expansion from density functional theory. We find that while the main structural distortions of the kagome lattice in the staggered tri-hexagonal CDW phase are along the nearest-neighbor V-V bonds, distortions associated with the Sb ions play a defining role in the energy gain in this and all other CDW states. Moreover, the coupling between ionic displacements from different unit cells is small, thus explaining the existence of multiple CDW instabilities with different modulations along the c-axis. We also investigate how pressure and temperature impact the CDW phase of CsV$_3$Sb$_5$. Increasing pressure does not change the staggered tri-hexagonal CDW ground state, even though the $M$-point CDW instability disappears before the $L$-point one, a behavior that we attribute to the large nonlinear coupling between the order parameters. Upon changing the temperature, we find a narrow regime in which another transition can take place, toward a tri-hexagonal Star-of-David CDW phase. We discuss the implications of our results by comparing them with experiments on this compound.

Patients Aged >50 Years With Anterior Shoulder Instability Have a Decreased Risk of Recurrent Dislocation After Operative Treatment Compared With Non-Operative Treatment

To compare the clinical outcomes of operative and nonoperative management, identify risk factors for recurrent instability, and identify risk factors for progression to surgery after failed nonoperative management for patients with first-time anterior shoulder dislocation after the age of 50 years. An established geographic medical record system was used to identify patients who experienced a first-time anterior shoulder dislocation after the age of 50 years. Patient medical records were reviewed to identify treatment decisions and outcomes of interest, including rates of frozen shoulder and nerve palsy, progression to osteoarthritis, recurrent instability, and progression to surgery. Outcomes were evaluated using Chi-square tests and survivorship curves were generated using Kaplan-Meier methods. A Cox model was developed to evaluate for potential risk factors of recurrent instability and progression to surgery after an initial trail of at least 3 months of nonoperative treatment. 179 patients were included with a mean follow-up of 11 years. 14% (n= 26) underwent early surgery within 3 months and 86% (n= 153) were initially treated nonoperatively. Mean age (59 years), was similar for both groups, but those that underwent early surgery had an increased rate of full-thickness rotator cuff tears (82% vs 55%; P= .01), labral tears (24% vs 8.0%; P= .01), and humeral head fracture (23% vs 8.5%; P= .03). When comparing the early surgery group to the nonoperative group, there were similar rates of persistent moderate-severe pain (19% vs 17%; P= .78) and frozen shoulder (8 vs 9%, respectively; P= .87) at final follow-up. Although nerve palsy (19% vs 8%; P= .08) and progression to osteoarthritis (20% vs 14%; P= .40) were more common in surgical patients, they experienced lower rates of recurrent instability after surgical intervention (0% vs 15%; P= .03) compared to nonoperatively treated patients. Increasing number of instability events prior to presentation was the greatest risk factor for recurrent instability (HR 232; P < .01). Fourteen percent (n= 21) failed initial nonoperative treatment and proceeded to surgical intervention at an average of 4.6 years after the initial instability event, and the greatest risk factors for progression to surgery were recurrent instability (HR 3.41; P < .01). Although the majority of patients >50 years that experience ASI are treated nonoperatively, those that require surgery tend to have more significant injury pathology, a lower risk of recurrent instability after surgery, but a higher progression to osteoarthritis compared to patients that do not require surgical intervention. There was no difference in pain severity at final follow-up, rates of frozen shoulder or nerve palsy between patients who underwent initial nonoperative treatment after instability and those who underwent surgery. A history of multiple instability episodes prior to presentation was the greatest predictor of recurrent instability and failure of nonoperative treatment and progression to surgery. Level III, retrospective cohort study.

CINmetrics: an R package for analyzing copy number aberrations as a measure of chromosomal instability.

Genomic instability is an important hallmark of cancer and more recently has been identified in others like neurodegenrative diseases. Chromosomal instability, as a measure of genomic instability, has been used to characterize clinical and biological phenotypes associated with these diseases by measuring structural and numerical chromosomal alterations. There have been multiple chromosomal instability scores developed across many studies in the literature; however, these scores have not been compared because of the lack of a single tool available to calculate and facilitate these various metrics. Here, we provide an R package CINmetrics, that calculates six different chromosomal instability scores and allows direct comparison between them. We also demonstrate how these scores differ by applying CINmetrics to breast cancer data from The Cancer Genome Atlas (TCGA). The package is available on CRAN at https://cran.rproject.org/package=CINmetrics and on GitHub at https://github.com/lasseignelab/CINmetrics.