Global Tilt Research Articles

Minority Vulnerability in South Asia and China

Abstract In recent years, a global tilt toward rightist majoritarianism has made Muslim and Christian minorities of Asia more vulnerable to violence and displacement. China’s program of “de-extremification” among the Uyghurs, Myanmar’s military operations against the Rohingya, and Hindutva-inspired violence in India illustrate strong-handed homogenizing impulses, even by governments that profess to embrace diversity. By examining these different contexts through a common lens, it becomes possible to recognize recurring patterns and think beyond the nation-state as the only framework for addressing minority vulnerability. After comparing Muslim and Christian vulnerability across a variety of Asian contexts, the essay explores the possibility of “Islamo-Christian” solidarity in the face of majoritarian violence. This new alignment defies a longstanding imperialist framework, whose geopolitics pits a Christian West against a Muslim other. It also embraces an ethic of empathy that transcends the language of “religious freedom” – a principle arising from the same geopolitics that manufactured majority-minority distinctions to begin with.

Sagittal alignment cut-off values for predicting future fall-related fractures in community-dwelling osteoporotic women.

Determining the optimal cut-off value of sagittal alignment for detecting osteoporotic patients at high risk for fall-related fractures is essential for understanding fracture risk and informing clinicians and physical therapists. We determined the optimal cut-off value of sagittal alignment for detecting osteoporotic patients at high risk for fall-related fractures in this study. In the retrospective cohort study, we enrolled a total of 255 women aged ≥ 65years who visited an outpatient osteoporosis clinic. We measured participants' bone mineral density and sagittal alignment, including sagittal vertical axis (SVA), pelvic tilt, thoracic kyphosis, pelvic incidence, lumbar lordosis, global tilt, and gap score at the initial visit. The cut-off value for sagittal alignment that was significantly associated with fall-related fractures was calculated after using multivariate Cox proportional hazards regression analysis. Ultimately, 192 patients were included in the analysis. After a mean follow-up of 3.0years, 12.0% (n = 23) had fractures due to falls. Multivariate Cox regression analysis confirmed that SVA (hazard ratio [HR] = 1.022, 95% confidence interval [CI] = 1.005-1.039) was the only independent predictor of fall-related fracture occurrence. The predictive ability of SVA for the occurrence of fall-related fractures was moderate (area under the curve [AUC] = 0.728, 95% CI = 0.623-0.834), with a cut-off value of 100mm for SVA. SVA classified by cut-off value was also associated with an increased risk of developing fall-related fractures (HR = 17.002, 95% CI = 4.102-70.475). We found that assessing the cut-off value of sagittal alignment would be useful information in understanding fracture risk in postmenopausal older women.

Correlation between surgical restoration of lumbar lordosis and the change in global tilt (GT) in adult spinal deformity

Correlation between surgical restoration of lumbar lordosis and the change in global tilt (GT) in adult spinal deformity

Association between sagittal alignment and loads at the adjacent segment in the fused spine: a combined clinical and musculoskeletal modeling study of 205 patients with adult spinal deformity

PurposeSagittal malalignment is a risk factor for mechanical complications after surgery for adult spinal deformity (ASD). Spinal loads, modulated by sagittal alignment, may explain this relationship. The aims of this study were to investigate the relationships between: (1) postoperative changes in loads at the proximal segment and realignment, and (2) absolute postoperative loads and postoperative alignment measures.MethodsA previously validated musculoskeletal model of the whole spine was applied to study a clinical sample of 205 patients with ASD. Based on clinical and radiographic data, pre-and postoperative patient-specific alignments were simulated to predict loads at the proximal segment adjacent to the spinal fusion.ResultsWeak-to-moderate associations were found between pre-to-postop changes in lumbar lordosis, LL (r = − 0.23, r = − 0.43; p < 0.001), global tilt, GT (r = 0.26, r = 0.38; p < 0.001) and the Global Alignment and Proportion score, GAP (r = 0.26, r = 0.37; p < 0.001), and changes in compressive and shear forces at the proximal segment. GAP score parameters, thoracic kyphosis measurements and the slope of upper instrumented vertebra were associated with changes in shear. In patients with T10-pelvis fusion, moderate-to-strong associations were found between postoperative sagittal alignment measures and compressive and shear loads, with GT showing the strongest correlations (r = 0.75, r = 0.73, p < 0.001).ConclusionsSpinal loads were estimated for patient-specific full spinal alignment profiles in a large cohort of patients with ASD pre-and postoperatively. Loads on the proximal segments were greater in association with sagittal malalignment and malorientation of proximal vertebra. Future work should explore whether they provide a causative mechanism explaining the associated risk of proximal junction complications.

Possibilities of Adaptive Optical Correction of the Global Wavefront Tilt Using Signals from Traditional and Polychromatic Laser Guide Stars

Possibilities of Adaptive Optical Correction of the Global Wavefront Tilt Using Signals from Traditional and Polychromatic Laser Guide Stars

Deep Reinforcement Learning for the Optimal Angle Control of Tracking Bifacial Photovoltaic Systems

An optimal tilt-angle control based on artificial intelligence (AI control) for tracking bifacial photovoltaic (BPV) systems is developed in this study, and its effectiveness and characteristics are examined by simulating a virtual system over five years. Using deep reinforcement learning (deep RL), the algorithm autonomously learns the control strategy in real time from when the system starts to operate. Even with limited deep RL input variables, such as global horizontal irradiance, time, tilt angle, and power, the proposed AI control successfully learns and achieves a 4.0–9.2% higher electrical-energy yield in high-albedo cases (0.5 and 0.8) as compared to traditional sun-tracking control; however, the energy yield of AI control is slightly lower in low-albedo cases (0.2). AI control also demonstrates a superior performance when there are seasonal changes in albedo. Moreover, AI control is robust against long-term system degradation by manipulating the database used for reward setting.

Iterative correction method of a retrace error in interferometry.

In interferometer measurements, the inconsistency of the optical range through which the reference and test lights pass introduces a retrace error in the phase measurement. In this study, we propose an iterative retrace error correction method in interferometry. A black-box model is established based on the linear and squared relationships between the retrace error and the tilt of the testing surface. The error correction phase is obtained using the least-squares method; thereafter, the global tilt is determined to iteratively correct the retrace error. The root mean square (RMS) of the residuals was > 3.2 × 10-5λ, >6.4 × 10-3λ, and >1.4 × 10-3λ in the simulation, experimentally computed retrace error correction in the planar measurement, and spherical measurement, respectively, proving that the retrace error can be effectively corrected.

Combined anterior-posterior versus all-posterior approaches for adult spinal deformity correction: a matched control study.

Anterior approaches are gaining popularity for adult spinal deformity (ASD) surgeries especially with the introduction of hyperlordotic cages and improvement in MIS techniques. Combined Approaches provide powerful segmental sagittal correction potential and increase the surface area available for fusion in ASD surgery, both of which would improve overall. This is the first study directly comparing surgical outcomes between combined anterior-posterior approaches and all-posterior approach in a matched ASD population. This is a retrospective matched control cohort analysis with substitution using a multicenter prospectively collected ASD data of patients with > 2year FU. Matching criteria include: age, American Society of Anesthesiologists Score, Lumbar Cobb angle, sagittal deformity (Global tilt) and ODI. In total, 1024 ASD patients were available for analysis. 29 Combined Approaches patients met inclusion criteria, and only 22 could be matched (1:2 ratio). Preoperative non-matched demographical, clinical, surgical and radiological parameters were comparable between both groups. Combined approaches had longer surgeries (548 mns vs 283) with more blood loss (2850ml vs 1471) and needed longer ICU stays (74h vs 27). Despite added morbidity, they had comparable complication rates but with significantly less readmissions (9.1% vs 38.1%) and reoperations (18.2% vs 43.2%) at 2years. Combined Approaches achieved more individualised and harmonious deformity correction initially. At the 2years control, Combined Approaches patients reported better outcomes as measured by COMI and SRS scores. This trend was maintained at 3years. Despite an increased initial surgical invasiveness, combined approaches seem to achieve more harmonious correction with superior sagittal deformity control; they need fewer revisions and have improved long-term functional outcomes when compared to all-posterior approaches for ASD deformity correction.

Global Alignment and Proportion (GAP) score in asymptomatic individuals: is it universal?

BACKGROUNDThe global alignment and proportion (GAP) score was established based on American and European subjects, which might limit its applicability to the Chinese population due to ethnicity-related difference of sagittal alignment. PURPOSETo analyze the applicability of GAP score in the Chinese population and to investigate the age- and gender-associated differences of spinopelvic and GAP score parameters. STUDY DESIGNA prospective cross-sectional radiographic study. PATIENTS SAMPLEOf 692 asymptomatic Chinese volunteers aged between 20 and 79 prospectively recruited between January 2017 and June 2019, 490 subjects were eventually included in this study. OUTCOME MEASURESThe pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), L1-S1 lordosis, L4-S1 lordosis, sagittal vertical axis (SVA), T1 pelvic angle (TPA) and global tilt (GT) were measured on lateral X-rays. The GAP scores and its parameters including relative pelvic version (RPV), relative lumbar lordosis (RLL), lordosis distribution index (LDI) and relative spinopelvic alignment (RSA) were calculated for each subject. METHODSSubjects were divided into four groups: Group 1M: male subjects <60 years old; Group 1F: female subjects <60 years old; Group 2M: male subjects ≥60 years old and Group 2F: female subjects ≥60 years old. The GAP scores and categories were determined and compared between groups. The results of sagittal alignment were compared with the previous studies evaluating the normative sagittal alignment in other populations. Univariate linear regression analysis was carried out between pelvic incidence (PI) and sacral slope (SS), lumbar lordosis (LL) and global tilt (GT) in each group. RESULTSThe distributions of GAP categories and the updated Roussouly classification were statistically different from other populations. Significantly different distribution of GAP categories was observed between Group 1M and Group 2M, Group 1F and Group 2F, and Group 1M and Group 1F. Radiographic measurements and GAP parameters were significantly different between Group 1M and Group 2M, and Group 1F and Group 2F. Gender-related difference of parameters was more prominent between Group 1M and Group 1F. Linear relationship of PI with SS, LL and GT were different from the regression models of “ideal” sagittal alignment in GAP score. CONCLUSIONSThe GAP score might be inappropriate in Chinese population due to ethnicity-related alignment difference. Worse feasibility of GAP score was observed in female and old subjects.

Variation of Global Sagittal Alignment Parameters According to Gender, Pelvic Incidence, and Age.

Retrospective cross-sectional study. The aim was to describe existing global sagittal alignment parameters across ages and to analyze differences according to gender and pelvic incidence (PI). Variability with age has been reported. It remains unclear how gender and spinopelvic morphology could additionally influence global alignment parameters. Radiographs of 2599 individuals (5-93 y) were analyzed. Translation parameters were: Sagittal Vertical Axis (SVA)-C7, SVA-C2, SVA-Center Acoustic Meatus (CAM), C7/Sacrofemoral Distance (SFD) ratio. Inclination parameters were: C7-Vertical Tilt (VT), T1-VT and T9-VT, Odontoid-Hip Axis (OD-HA), OD-CAM. Pelvic compensation parameters were: T1-Pelvic Angle (TPA), Global Tilt (GT), Spino-Sacral Angle (SSA). Global sagittal alignment (GSA) was considered among formulae. The distribution of parameters was analyzed using a Bayesian inference. Correlations with spinopelvic parameters were investigated. SVA-C7, SVA-C2, SVA-CAM were larger in males and high PI, and increased significantly after 50 years (Pr>0.9999). C7/SFD decreased during growth and was larger in low PI (Pr=0.951). There was no correlation with spinopelvic parameters. Age-related variations of inclination parameters were nonsignificant. T1-VT and T9-VT increased with PI and were significantly larger in high PI (Pr>0.95). C7-VT was significantly larger in low PI (Pr>0.9999). OD-HA and OD-CAM were constant and increased after 80 years. TPA and GT increased with PI (Pr>0.9999) and age after 35 years (Pr>0.9999). SSA decreased nonsignificantly after 50 years. TPA correlated with PI (ρ=0.6130) and pelvic tilt (PT) (ρ=0.8375). GT correlated with PI (ρ=0.5961) and PT (ρ=0.8996). SSA correlated with sacral slope (ρ=0.9026). GSA was larger in high PI (Pr>0.9999) and increased after 35 years (Pr>0.9999). GSA correlated with PT (ρ=0.7732). Translation parameters increase with age, more prominently in males and high PI. Variations of inclination parameters are smaller. Pelvic compensation parameters and GSA increase with age and are closely related to PT and spinopelvic morphology. Level III.

The Most Intense Deflation of the Last Two Decades at Mt. Etna: The 2019–2021 Evolution of Ground Deformation and Modeled Pressure Sources

AbstractWe analyze Global Navigation Satellite System (GNSS) and tilt data from the permanent monitoring networks of Etna volcano starting just after the 24 December 2018 eruption to an unusual two‐month period of deflation in February–March, 2021, which coincided with the occurrence of 17 lava fountain episodes. Based on changes in slope in the GNSS displacement time series, we divide the period starting 7 months after the eruption into five phases, spanning the continued inflation of the edifice punctuated by short periods of effusive and strombolian activity (four phases) and a 2‐month phase of intensive deflation. Our model indicates a progressive deepening of the internal pressure sources followed by a fast ascending source starting two‐months before the first 2021 paroxysms. We explain these results in light of a recent volcanological model on the nature and behavior of magma ascending through the Etnean feeding system.

Does the thoracolumbar kyphosis secondary to ankylosing spondylitis affect the iliac trajectory of S2AI screw?

BackgroundThe study aimed to evaluate the influence of thoracolumbar kyphosis secondary to ankylosing spondylitis (AS) on parameters of S2AI trajectory and to compare the ideal S2AI trajectory with those of the non-deformity patients with AS, sagittal deformity patients without AS, and the normal population reported in literatures.MethodsSagittal parameters including global kyphosis (GK), pelvic tilt (PT) and sacral slope (SS) were measured. Besides, according to the simulated ideal S2AI trajectory on the CT images, trajectory parameters were measured including Sag angle, Tsv angle, Max-length, Sacral distance and Iliac width. Starting-point parameters were also measured including PSIS distance, Skin distance, Iliac wing and S2 midline.ResultsNinety-four AS-related thoracolumbar kyphosis patients were included. After adjusting the age and gender, twenty non-deformity patients with AS and 20 sagittal deformity patients without AS were selected to compare with patients with AS-related thoracolumbar kyphosis, respectively. Sag angle in deformity patients with AS was smaller than other two groups (P < 0.001). No difference was found in Tsv angle and Sacral distance between AS patients with and without deformity. However, these two parameters were shown significant differences between deformity patients with AS and without AS. In deformity patients with AS, no significant differences were found in all parameters between genders Furthermore, there were strong correlations between PT and the bilateral Sag angle (P < 0.001).ConclusionsThe thoracolumbar kyphosis secondary to AS affects the Sag angle of the ideal S2AI trajectory which was approximately 20° smaller than that in non-deformity patients with AS, sagittal deformity patients without AS, and the normal population. Additionally, the Tsv angle and the Sacral distance in AS patients with thoracolumbar kyphosis were about 10° and 10 mm larger than those in sagittal deformity patients without AS, and the normal population reported in literatures.

Design and Optimize the Performance of Self-Powered Photodetector Based on PbS/TiS3 Heterostructure by SCAPS-1D.

Titanium trisulphide (TiS3) has been widely used in the field of optoelectronics owing to its superb optical and electronic characteristics. In this work, a self-powered photodetector using bulk PbS/TiS3 p-n heterojunction is numerically investigated and analyzed by a Solar Cell Capacitance Simulator in one-Dimension (SCAPS-1D) software. The energy bands, electron-holes generation or recombination rate, current density-voltage (J-V), and spectral response properties have been investigated by SCAPS-1D. To improve the performance of photodetectors, the influence of thickness, shallow acceptor or donor density, and defect density are investigated. By optimization, the optimal thickness of the TiS3 layer and PbS layer are determined to be 2.5 μm and 700 nm, respectively. The density of the superior shallow acceptor (donor) is 1015 (1022) cm−3. High quality TiS3 film is required with the defect density of about 1014 cm−3. For the PbS layer, the maximum defect density is 1017 cm−3. As a result, the photodetector based on the heterojunction with optimal parameters exhibits a good photoresponse from 300 nm to 1300 nm. Under the air mass 1.5 global tilt (AM 1.5G) illuminations, the optimal short-circuit current reaches 35.57 mA/cm2 and the open circuit voltage is about 870 mV. The responsivity (R) and a detectivity (D*) of the simulated photodetector are 0.36 A W−1 and 3.9 × 1013 Jones, respectively. The simulation result provides a promising research direction to further broaden the TiS3-based optoelectronic device.

Sagittal balance and intervertebral disc composition in patients with low back pain.

The aim of this study was to verify the relationship between quantitative T2 relaxation measurements of lumbar intervertebral discs (IVDs) and spinopelvic parameters in patients with chronic low back pain. The study was approved by the Clinical Hospital of the Ribeirao Preto Medical School (USP) Ethics Committee, and written consent was obtained from all patients. A total of 455 IVDs from 91 consecutive patients with chronic low back pain were included in this prospective study. All subjects were assessed using the Oswestry Disability Index and visual analogue scale questionnaires and were confirmed to have no other spine diseases except disc degeneration. Spinopelvic parameters including the pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), sagittal vertical axis (SVA), global tilt (GT), T1 pelvic angle (TPA), lumbar lordosis (LL), thoracic kyphosis (TK), pelvic incidence minus lumbar lordosis mismatch (PI-LL), and lack of lumbar lordosis (LLL) were measured. The study group was categorized according to the Roussouly classification. Sagittal T2 maps were acquired to extract the IVD relaxation times, and the complete manual segmentation of IVDs at all levels was performed using Display® software. Lumbar IVD T2 relaxation times showed significant correlation with PT (P<0.01), GT (P<0.01), TPA (P<0.01), PI-LL (P=0.01), and LLL (P=0.01). No difference was noted between Roussouly subtypes regarding T2 relaxation times at any disc level. Data from questionnaires showed no correlation with T2 relaxation times. Global tilt and T1 pelvic angle were correlated with IVD composition changes (T2 relaxometry). There was no correlation between clinical symptoms and IVD T2 relaxation times.

Possibilities of adaptive optical correction of the global wavefront tilt using signals from traditional and polychromatic laser guide stars

Possibilities of adaptive optical correction of the global wavefront tilt using signals from traditional and polychromatic laser guide stars

Obeid-Coronal Malalignment Classification Is Age Related and Independently Associated to Personal Reported Outcome Measurement Scores in the Nonfused Spine.

ObjectiveTo evaluate Obeid-coronal malalignment (O-CM) modifiers according to age, sagittal alignment, and patient-reported outcome measures (PROMs), in the mobile spine. MethodsRetrospective review of a prospective multicenter adult spinal deformity (ASD) database with 1,243 (402 nonoperative, 841 operative) patients with no prior fusion surgery. Patients were included if they were aged over 18 years and were affected by spinal deformity defined by one of: Cobb angle ≥ 20°, pelvic tilt ≥ 25°, sagittal vertical axis ≥ 5 cm, thoracic kyphosis ≥ 60°. Patients were classified according to the O-CM classification and compared to coronally aligned patients. Multivariate analysis was performed on the relationship between PROMs and age, global tilt (GT) and coronal malalignment (CM). ResultsFour hundred forty-three patients had CM of more than 2 cm compared to 800 who did not. The distribution of these modifiers was correlated to age. After multivariate analysis, using age and GT as confounding factors, we found that before the age of 50 years, 2A1 patients had worse sex life and greater satisfaction than patients without CM. After 50 years of age, patients with CM (1A1, 1A2) had worse self-image and those with 2A2, 2B had worse self-image, satisfaction, and 36-item Short Form Health Survey physical function. Self-image was the consistent determinant of patients opting for surgery for all ages. ConclusionCM distribution according to O-CM modifiers is age dependent. A clear correlation between the coronal malalignment and PROMs exists when using the O-CM classification and in the mobile spine, this typically affects self-image and satisfaction. Thus, CM classified according to O-CM modifiers is correlated to PROMs and should be considered in ASD.

Radiographic outcomes and complications after L4 or L5 pedicle subtraction osteotomy for fixed sagittal malalignment in 102 adult spinal deformity patients with a minimum 2-year follow-up.

The objective of this retrospective study was to provide the radiographic outcomes and complications for pedicle subtraction osteotomy (PSO) performed at the low lumbar spine, i.e., L4 or L5 for ASD patients with fixed sagittal malalignment. ASD patients who underwent L4 or L5 PSO with a minimum 2-year follow-up were included. Preoperative and postoperative radiographs, and complications were collected. Radiographic analysis included lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), thoracic kyphosis (TK), sagittal vertical axis (SVA), spinal lordosis (SL) ratio and global tilt (GT) on standing long-cassette radiographs. A total of 102 patients from 2 spinal centers were analyzed. 66 patients underwent PSO at L4 and 36 patients at L5. From preoperatively to the final follow-up, significant improvements occurred in LL (from -31° to -52°), SVA (from 13 to 5cm), and GT (from 44° to 27°) (all, p < 0.05). 12 patients had transient neurological deficits, and 8 patients had persistent neurological deficit. 23 patients underwent revision for PJK (2), pseudarthrosis (10), neurological deficit (2), epidural hematoma (1), or deep surgical site infection (8). No PJK was observed in any of the patients with L5 PSO. PSO at the level of L4 or L5 remains a challenging technique but with an acceptable rate of complications and revisions. It enables correction of fixed sagittal malalignment in ASD patients with a globally satisfactory outcome. In comparison with L4 PSO, L5 PSO patients did not show PJK as a mechanical complication. Distal lumbar PSO at the level of L5 may represent one of the factors that may help preventing the proximal junctional kyphosis complication.

Analysis of Aero-Optical Jitter in Convective Turbulent Flows Using Stitching Method

In the typical analysis of aero-optical wave-front data, the three lowest-order spatial modes (namely, unsteady piston as well as and tilts) are removed from the experimentally measured wave fronts. These modes are commonly corrupted by mechanical disturbances. In this work, an algorithm called the stitching method was developed that takes advantage of the advective nature of the optical aberrations caused by turbulent structures to recover the unsteady global X-tilt and piston modes from experimental time-resolved wave fronts. One-dimensional modeling and related uncertainty analysis showed that for the wave fronts collected with sufficient sampling frequency, the algorithm is able to correctly recover the aero-optical component of the unsteady X tilt. In this manner, the time series of true wave fronts can be recovered. To further validate the stitching method, spatiotemporal wave-front measurements were conducted on a Mach 0.6/0.1 forced shear layer. The predicted results for the rms of the aero-optical X tilt from the stitching method agree well with the modeled results. Since the stitching method recovers the time series of the aero-optical global X tilt, the global tilt spectra were also computed and presented. This information can be used by system designers to specify the requirements for adaptive-optics system components, such as fast steering mirrors in airborne directed energy systems.

Strain states and relaxation for alpha-(Al_xGa_{1-x})_2O_3 thin films on prismatic planes of alpha-Al_2O_3 in the full composition range: Fundamental difference of a- and m-epitaxial planes in the manifestation of shear strain and lattice tilt

Pseudomorphic and relaxed alpha-(Al_xGa_{1-x})_2O_3 thin films are grown by combinatorial pulsed laser deposition in the entire composition range on prismatic a- and m-plane alpha-Al_2O_3 substrates. Pseudomorphic growth on m-plane sapphire has been achieved for x ge 0.45. A distinct difference between the a- and m-epitaxial plane is observed in reciprocal space map measurements being in agreement with continuum elasticity theory for rhombohedral heterostructures. While pseudomorphic layers on m-plane sapphire show a pronounced shear strain e'_5 along the c-axis direction, relaxed layers exhibit a global lattice tilt in the same direction. Both effects are not present on the a-epitaxial plane. Out-of-plane lattice constants as well as e'_5 are modeled as function of x employing elasticity theory, confirming theoretical values of the elastic stiffness tensor for alpha-Ga_2O_3, especially the non-zero value of the C_{14} component. Possible pyramidal slip systems for strain relaxation in c-axis direction are examined to explain and numerically model the difference in lattice tilt for the two substrate orientations.Graphic abstract

P84. Which components of the global alignment proportionality score have the greatest impact on outcomes in adult spinal deformity corrective surgery?

P84. Which components of the global alignment proportionality score have the greatest impact on outcomes in adult spinal deformity corrective surgery?