Thread Configuration Research Articles

Towards bit threads in general gravitational spacetimes

The concept of the generalized entanglement wedge was recently proposed by Bousso and Penington, which states that any bulk gravitational region a possesses an associated generalized entanglement wedge E(a) ⊃ a on a static Cauchy surface M in general gravitational spacetimes, where E(a) may contain an entanglement island I(a). It suggests that the fine-grained entropy for bulk region a is given by the generalized entropy Sgen(E(a)). Motivated by this proposal, we extend the quantum bit thread description to general gravitational spacetimes, no longer limited to the AdS spacetime. By utilizing the convex optimization techniques, a dual flow description for the generalized entropy Sgen(E(a)) of a bulk gravitational region a is established on the static Cauchy surface M, such that Sgen(E(a)) is equal to the maximum flux of any flow that starts from the boundary ∂M and ends at bulk region a, or equivalently, the maximum number of bit threads that connect the boundary ∂M to the bulk region a. In addition, the nesting property of flows is also proved. Thus the basic properties of the entropy for bulk regions, i.e. the monotonicity, subadditivity, Araki-Lieb inequality and strong subadditivity, can be verified from flow perspectives by using properties of flows, such as the nesting property. Moreover, in max thread configurations, we find that there exists some lower bounds on the bulk entanglement entropy of matter fields in the region E(a) \\ a, particularly on an entanglement island region I(a) ⊂ (E(a) \\ a), as required by the existence of a nontrivial generalized entanglement wedge. Our quantum bit thread formulation may provide a way to investigate more fine-grained entanglement structures in general spacetimes.

Geometrizing the partial entanglement entropy: from PEE threads to bit threads

We give a scheme to geometrize the partial entanglement entropy (PEE) for holographic CFT in the context of AdS/CFT. More explicitly, given a point x we geometrize the two-point PEEs between x and any other points in terms of the bulk geodesics connecting these two points. We refer to these geodesics as the PEE threads, which can be naturally regarded as the integral curves of a divergenceless vector field Vxμ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {V}_{\ extbf{x}}^{\\mu } $$\\end{document}, which we call PEE thread flow. The norm of Vxμ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {V}_{\ extbf{x}}^{\\mu } $$\\end{document} that characterizes the density of the PEE threads can be determined by some physical requirements of the PEE. We show that, for any static interval or spherical region A, a unique bit thread configuration can be generated from the PEE thread configuration determined by the state. Hence, the non-intrinsic bit threads are emergent from the intrinsic PEE threads. For static disconnected intervals, the vector fields describing a divergenceless flow is no longer suitable to reproduce the RT formula. We weight a PEE thread with the number of times it intersects with any homologous surface. Instead, the RT formula is perfectly reformulated by the minimization of the summation of PEE threads with all possible assignment of weights.

The Potential of Double-Faced Polyester-Viscose Woven Fabric as a Porous Substrate for Direct-Coating and Multilayer Concept.

Textile-based sensors fabricated using the direct-coating method are the appropriate choice to meet the aspects of flexibility, non-invasiveness, and lightness for continuous monitoring of the human body. The characteristics of the sensor substrate are directly influenced by factors such as the type of weave, thread fineness, fabric density, and the type of polymeric constituent fibers. The fabric used as the sensor substrate, fabricated using the direct-coating method, must be capable of retaining the electrode paste solution, which has higher viscosity, on one surface of the fabric to avoid short circuits during the fabrication process. However, during its application, this fabric should allow the easy passage of analyte solutions with low viscosity as much as possible. Hence, an appropriate fabric construction is required to serve as the substrate for textile-based sensors to ensure the success of the fabrication process and the effectiveness of the resulting sensor's performance. The development of the structural design of the fabric to be used as a substrate for non-invasive biosensors with a multilayer concept is carried out by weaving and sewing processes utilizing polyester-viscose fibers. During the production process, variations are applied, such as weft yarn density, the characterization of wetting time, absorption rate, maximum wetted radius, spreading speed, and accumulative one-way transport index. The most suitable fabric for use as a substrate for non-invasive biosensors with a multilayer concept, such as in this research, is a fabric with a weft thread density of 70 strands per inch, along with the addition of an analyte transfer thread configuration.

Revisiting thread configuration of SpMV kernels on GPU: A machine learning based approach

Sparse matrix-vector multiplication (SpMV) optimization on GPUs has been challenging due to irregular memory accesses and unbalanced workloads. The majority of existing solutions assign a fixed number of threads to one or more rows of sparse matrices according to empirical formulas. However, this method does not give the optimal thread configuration and results in a significant performance loss. This paper proposes a new machine learning-based thread assignment strategy for SpMV on GPU, predicting the near-optimal thread configuration for matrices. Further, we partition irregular sparse matrices into blocks according to the distribution of non-zero elements and predict the optimal thread configuration for each block. A new SpMV kernel is designed to accelerate the execution of different blocks. Experimental results show that our machine learning-based approach can select the near-optimal thread configuration for most matrices. The efficiency of SpMV for irregular matrices is also improved by matrix partitioning and blockwise prediction. Finally, we dive into the trained model to find out the connection between the features of a sparse matrix and its optimal thread configuration.

Improving dental implant stability by optimizing thread design: Simultaneous application of finite element method and data mining approach

Lack of knowledge regarding the optimal design of thread configuration in dental implants, which can offer a satisfactory level of stability in the implant-bone construct, is a significant challenge in the field of dental biomechanics. The purpose of this finite element analysis study was to identify the optimal thread design by investigating the effects of thread parameters such as thread depth (TD), thread width (TW), and thread pitch (TP), as well as upper (α) and lower (β) thread angles, on the maximum principal stress in cancellous and cortical bone, maximum von Mises stress in the dental implant, and maximum shear stress at the implant-bone interface. A finite element model of an alveolar bone segment with a dental implant was developed. The Latin hypercube sampling method was used to generate a dataset of virtual experiments, which were analyzed by using the decision tree method to identify suitable thread designs that minimize mechanical stimuli. Additionally, the effectiveness of thread parameters on stress levels in the bone, implant, and their interface were assessed. The results of this study, verified by comparison with previous literature, indicated that TD, TW, and upper thread angle were the most effective parameters in promoting implant stability. By analyzing the decision trees, optimum ranges for all the thread parameters were determined as follows: 0.25<TD<0.34, 0.25≤TW≤0.28, 0.8≤TP≤0.88, 66.2≤α≤80, and β≤65.4, which led to the V-shape thread design.

Full-Stack Optimizing Transformer Inference on ARM Many-Core CPU

The past several years have witnessed tremendous success of transformer models in natural language processing (NLP), and their current landscape is increasingly diverse. Although GPU gradually becomes the dominating workhorse and de facto standard for deep learning, there are still many scenarios where using CPU remains a prevalent choice. Recently, ARM many-core processor starts emigrating to cloud computing and high-performance computing, which is promising to deploy transformer inference. In this paper, we identify several performance bottlenecks of existing inference runtime on many-core CPU including low-core usage, isolated thread configuration, inappropriate implementation of general matrix multiply (GEMM), and redundant computations for variable-length inputs. To tackle these problems, full-stack and cross-layer optimizations are conducted for these challenges from deep learning service level to the neural network operator level. We explore multi-instance parallelization at the service level to improve CPU core usage. To improve parallel efficiency of the inference runtime, we design NUMA-aware thread scheduling and a look-up table for optimal parallel configurations. The GEMM implementation is tailored for some critical modules such self-attention module to exploit the characteristics of transformer workload. To eliminate redundant computations, a novel storage format is designed and implemented to pack sparse data and a load balancing strategy is proposed for tasks with different sparsity. Experimental results show that our implementation can outperform existing solutions by 1.1x to 6x for different transformer-based models with fixed-length inputs. For variable-length inputs, it achieves 1.9x to 6x speedups on Kungpeng920 processor and 3x to 8x speedups on Ampere Altra processor depending on different sequence lengths and batch sizes.

Thread/State correspondence: from bit threads to qubit threads

Starting from an interesting coincidence between the bit threads and SS (surface/state) correspondence, both of which are closely related to the holographic RT formula, we introduce a property of bit threads that has not been explicitly proposed before, which can be referred to as thread/state correspondence (see [50] for a brief pre-release version). Using this thread/state correspondence, we can construct the explicit expressions for the SS states corresponding to a set of bulk extremal surfaces in the SS correspondence, and nicely characterize their entanglement structure. Based on this understanding, we use the locking bit thread configurations to construct a holographic qubit threads model as a new toy model of the holographic principle, and show that it is closely related to the holographic tensor networks, the kinematic space, and the connectivity of spacetime.

Reinforcement of Timber Dowel-Type Connections Using Self-Tapping Screws and the Influence of Thread Configurations

The application of self-tapping screws as reinforcement on glulam connections has been proven effective. However, the implication of different thread configurations on the effectiveness of reinforcement remains unknown. This paper conducted experiments using screws with various thread configurations in embedment-strength tests and tensile connection tests. Results show that self-tapping screws with one third of thread achieved similar improvement in the embedment strength and mechanical properties of connections as fully threaded screws. This implies that properly reducing the thread length on self-tapping screws ensures easier screw installation than using fully threaded screws. The influence of screw-to-dowel distance was also investigated and two distances (0.5 d and 1 d) were adopted, with ‘d’ being the diameter of the dowel. The difference in embedment strength due to different screw-to-dowel distances was insignificant. The group with screws placed in contact (0.5 d) with the dowel achieved 5% higher embedment strength than the group with screws placed at a 1 d distance. The connection tests showed good agreement with the embedment-strength tests. This confirms that self-tapping screws with reduced thread can enhance the load-carrying capacity and ductility of connections to a level similar to connections reinforced by fully threaded screws.

Optimization of thread configuration in dental implants through regulating the mechanical stimuli in neighboring bone

Background and objectiveThe threads, as the most critical component of dental implants, transfer the imposed occlusal loads to the adjacent bone. Moreover, regulation of the mechanical stimuli in the implant adjacent bone is crucial to maximize the bone-implant construct stability. An optimal thread design can be resulted when the distribution of mechanical stimuli within the bone, and at the implant-bone interface, lie in an advised confined range. In this work, with the goal of finding the optimal thread design, which can provide the maximum level of stability, the effects of thread parameters, namely, thread depth, thread width, and thread pitch, together with upper and lower thread angles, on maximum principal strain within the cortical and cancellous bone, and shear strain at the implant-bone interface, were investigated. MethodsIn this study, the response surface methodology (RSM), due to the central composite design (CCD), was employed to obtain a set of 53 experiments. Following that, they were numerically simulated using the finite element method (FEM). The polynomial regression model was then used to predict the response functions based on the magnitude of thread parameters. The effectiveness of each thread parameter was also evaluated through statistical tools. Moreover, the non-dominated sorting genetic algorithm (NSGA-II) was performed to find the optimum dimensions of the thread. ResultsThrough comparing the results obtained from analyzing initial and optimized configuration of threads, it was shown that the latter causes a reduction in the maximum principal strains in cancellous and cortical bones by about 25% and 30%, respectively, which is in favor of making a higher quality bone, and thus greater stability in dental implant-bone construct. Moreover, the maximum shear strains at the implant-bone interface in different planes were reduced by about 40%, in the optimized thread, compared with the initial design. ConclusionsThe optimized design found in this study is a buttress thread with a fine pitch, but deep thread, which keeps the mechanical stimuli in a safe range to grant an acceptable level of stability.

Evaluation of instrumentation and pedicle screw design for posterior lumbar fixation: A pre-clinical in vivo/ex vivo ovine model.

Stabilization procedures of the lumbar spine are routinely performed for various conditions, such as spondylolisthesis and scoliosis. Spine surgery has become even more common, with the incidence rates increasing ~30% between 2004 and 2015. Various solutions to increase the success of lumbar stabilization procedures have been proposed, ranging from the device's geometrical configuration to bone quality enhancement via grafting and, recently, through modified drilling instrumentation. Conventional (manual) instrumentation renders the excavated bony fragments ineffective, whereas the "additive" osseodensification rotary drilling compacts the bone fragments into the osteotomy walls, creating nucleating sites for regeneration. This study aimed to compare both manual versus rotary Osseodensification (OD) instrumentation as well as two different pedicle screw thread designs in a controlled split animal model in posterior lumbar stabilization to determine the feasibility and potential advantages of each variable with respect to mechanical stability and histomorphology. A total of 164 single thread (82 per thread configuration), pedicle screws (4.5× 35 mm) were used for the study. Each animal received eight pedicles (four per thread design) screws, which were placed in the lumbar spine of 21 adult sheep. One side of the lumbar spine underwent rotary osseodensification instrumentation, while the contralateral underwent conventional, hand, instrumentation. The animals were euthanized after 6- and 24-weeks of healing, and the vertebrae were removed for biomechanical and histomorphometric analyses. Pullout strength and histologic analysis were performed on all harvested samples. The rotary instrumentation yielded statistically (p= 0.026) greater pullout strength (1060.6N ± 181) relative to hand instrumentation (769.3N ± 181) at the 24-week healing time point. Histomorphometric analysis exhibited significantly higher degrees of bone to implant contact for the rotary instrumentation only at the early healing time point (6 weeks), whereas bone area fraction occupancy was statistically higher for rotary instrumentation at both healing times. The levels of soft tissue infiltration were lower for pedicle screws placed in osteotomies prepared using OD instrumentation relative to hand instrumentation, independent of healing time. The rotary instrumentation yielded enhanced mechanical and histologic results relative to the conventional hand instrumentation in this lumbar spine stabilization model.

Entropy production and enhanced thermal performance studies on counter-flow double-channel hydrogen/ammonia-fuelled micro-combustors with different shaped internal threads

This study presents a numerical analysis of first and second Law performances of counterflow double-channel micro-combustors. A parametric analysis is conducted to determine the influence of the inlet velocity, the chamber geometry, and the fuel composition on the mean wall temperature, the uniformity of the wall temperature, and the second law characteristics. We show that the double-channel combustor greatly increases the uniformity of the wall compared to the single channel configuration. The oval shaped thread configuration results in the highest wall temperature and the wall temperature uniformity. Increasing inlet velocity results in an increased mean wall temperature and a slightly reduced wall temperature uniformity. The greatest contributor to entropy generation is found to be resulting from chemical reaction. The analysis showed that the second law efficiency was just below 0.5 regardless of the thread shapes. The thread shapes had no major influence on the combustor exergy. A blended ammonia-hydrogen fuel is shown to be resulted in a slightly higher mean wall temperature and a less uniform wall temperature.

Crossing Versus Locking: Bit Threads and Continuum Multiflows

Bit threads are curves in holographic spacetimes that manifest boundary entanglement, and are represented mathematically by continuum analogues of network flows or multiflows. Subject to a density bound, the maximum number of threads connecting a boundary region to its complement computes the Ryu–Takayanagi entropy. When considering several regions at the same time, for example in proving entropy inequalities, there are various inequivalent density bounds that can be imposed. We investigate for which choices of bound a given set of boundary regions can be “locked”, in other words can have their entropies computed by a single thread configuration. We show that under the most stringent bound, which requires the threads to be locally parallel, non-crossing regions can in general be locked, but crossing regions cannot, where two regions are said to cross if they partially overlap and do not cover the entire boundary. We also show that, under a certain less stringent density bound, a crossing pair can be locked, and conjecture that any set of regions not containing a pairwise crossing triple can be locked, analogously to the situation for networks.

Screw Thread Configuration Has No Effect on Operative Outcomes of Slipped Capital Femoral Epiphysis

INTRODUCTION The current “gold standard” treatment for slipped capital femoral epiphysis (SCFE) is insertion of a single cannulated screw down the epiphyseal center. Debate remains as to whether partially- (PTCS) or fully-threaded (FTCS) cannulated screws, and what number, are optimal. The present retrospective cohort study compares such constructs in a clinical model. METHODS IRB approval was obtained. Patients (N=158) presenting to a level-one pediatric trauma center for in situ pinning of SCFE between January 2005 and April 2018 were included. Covariates analyzed were sex, race, BMI, history of endocrinopathy, and preoperative designation of unstable SCFE. Outcomes included return to the operating room (OR), avascular necrosis (AVN), hardware failure/removal, and the sequelae of femoroacetabular impingement (FAI). Multivariable logistic regression models included covariates with significant univariate effects, as well as thread configuration, number of screws, preoperative instability, and the screw*thread and screw*instability interactions. RESULTS Average patient age at surgery was 12.3±1.9 years; 63% of patients were male; 68% of patients were White/Caucasian and the remaining 32% were Black/African American. Mean BMI was 28.4±6.4 kg∙m-2. PTCS were utilized in 81.0% of constructs and 1 screw was placed in 83.5% of hips. Outcome rates were as follows: return to OR=15.8%, AVN=7.6%, FAI=7.0%, hardware failure/removal=9.5%. Univariate modeling demonstrated no significant covariate effects on return to OR (each P≥0.181) or AVN (each P≥0.099). Sex had a significant effect on FAI (P=0.012). Age and bilateral SCFE were significantly related to hardware failure/removal (P=0.039 and P=0.015, respectively). Multivariable models found that 2 screw constructs were associated with increased odds of return to OR [P=0.027; OR=3.01 (1.13-7.98)]. Odds of AVN were increased by older age (P=0.024; OR=1.45 [1.03-2.03]) and 2 screw constructs in stable SCFE [screws*stability interaction: P&lt;0.001; OR=60.5 (5.60-652.31)]. Female sex increased odds of FAI (P=0.012; OR=5.17 [1.31-20.36]). Finally, odds of hardware failure/removal were increased by 2 screw constructs [P=0.038; OR=3.64 (1.13-11.70)] and bilateral SCFE [P=0.027; OR=3.51 (1.15-10.74)]. DISCUSSION AND CONCLUSION A single, PTCS comprises the majority of SCFE constructs, and this construct carries the least risk for negative outcomes in cases of stable SCFE. These data demonstrate no significant effects of thread configuration on outcomes. The authors caution orthopaedic surgery providers against using more than one screw in cases of stable SCFE, as well as to monitor older, female, and/or bilateral SCFE patients more closely due to an increased risk for complications.

Thread-Based Modeling and Analysis in Multi-Core-Based V2X Communication Device

We propose a thread-based modeling and analysis method for a vehicle-to-everything (V2X) communication device, according to the performance requirements of the V2X application. For a developer to develop a V2X device or application, its performance requirements must first be determined. Furthermore, the developer selects the hardware system to enable the service to function while satisfying the performance requirements. Through this process, the developer designs and creates the program in a manner that considers thread configuration and core mapping with the given hardware resources. Then, the performance evaluation of a system is tested via instruction-level program analysis with executable programs. This process is an essential procedure for developing a program that satisfies the performance requirements. However, the debugging procedure repeated through program development, performance analysis, and program modification requires significant time and is costly. Hence, to reduce the time and cost of unnecessary work, we propose a thread-level modeling and analysis method using a queueing theory for a V2X communication device that can be applied at the design level. First, we propose a thread-level performance modeling and analysis method based on queuing theory in a multi-core-based vehicle service system. Furthermore, we analyze the performance of a multi-core-based vehicle service system utilizing the proposed method.

Screw Thread Configuration Has No Effect on Outcomes of In Situ Fixation for Stable Slipped Capital Femoral Epiphysis.

No consensus exists regarding the optimal surgical management of slipped capital femoral epiphysis (SCFE). Treatment goals include avoiding slip progression and sequelae such as avascular necrosis (AVN). Factors associated with surgical implants merit further research. This study investigates the effect of screw thread configuration and the number of screws on surgical outcomes. A total of 152 patients undergoing cannulated, stainless steel, in situ screw fixation of SCFE between January 2005 and April 2018 were included. Procedure laterality, screw number and thread configuration (partially threaded/fully threaded), bilateral diagnosis, Loder classification, final follow-up, patient demographics, and endocrinopathy history were analyzed. Primary outcomes were return to the operating room (ROR), AVN, hardware failure/removal, and femoroacetabular impingement (FAI). Most patients received a single (86.2%), partially threaded (81.6%) screw; most were unilateral (67.8%) and stable (79.6%). Mean follow-up was 2.0±2.7 years, with a 15.8% rate of ROR, 5.3% exhibiting AVN, 6.6% exhibiting FAI, and 9.2% experiencing hardware failure/removal. Number of screws was the sole predictor of ROR [odds ratio (OR)=3.35, 95% confidence interval (CI): 1.18-9.49]. Unstable SCFE increased the odds of AVN (OR=38.44; 95% CI: 4.35-339.50) as did older age (OR=1.43, 95% CI: 1.01-2.03). Female sex increased risk for FAI (OR=4.87, 95% CI: 1.20-19.70), and bilateral SCFE elevated risk for hardware failure/removal versus unilateral SCFE (OR=4.41, 95% CI: 1.39-14.00). Screw thread configuration had no significant effect on any outcome (for each, P ≥0.159). Rates of ROR, AVN, FAI, and hardware failure/removal did not differ between patients treated with partially threaded or fully threaded screws. The use of 2 screws was associated with an increased likelihood of ROR. These findings suggest that screw thread configuration has no impact on complication rates, whereas screw number may be an important consideration in SCFE fixation. Level III-retrospective cohort study.

Additive Manufacturing of Novel Hybrid Monolithic Ceramic Substrates

Additive manufacturing (AM) can revolutionise engineering by taking advantage of unconstrained design and overcoming the limitations of traditional manufacturing capabilities. A promising application of AM is in catalyst substrate manufacturing, aimed at the enhancement of the catalytic efficiency and reduction in the volume and weight of the catalytic reactors in the exhaust gas aftertreatment systems. This work addresses the design and fabrication of innovative, hybrid monolithic ceramic substrates using AM technology based on Digital Light Processing (DLP). The designs are based on two individual substrates integrated into a single, dual-substrate monolith by various interlocking systems. These novel dual-substrate monoliths lay the foundation for the potential reduction in the complexity and expense of the aftertreatment system. Several examples of interlocking systems for dual substrates were designed, manufactured and thermally post-processed to illustrate the viability and versatility of the DLP manufacturing process. Based on the findings, the sintered parts displayed anisotropic sintering shrinkage of approximately 14% in the X–Y direction and 19% in the Z direction, with a sintered density of 97.88 ± 0.01%. Finally, mechanical tests revealed the mechanical integrity of the designed interlocks. U-lock and Thread configurations were found to sustain more load until complete failure.

Sewing spacetime with Lorentzian threads: complexity and the emergence of time in quantum gravity

Holographic entanglement entropy was recently recast in terms of Riemannian flows or ‘bit threads’. We consider the Lorentzian analog to reformulate the ‘complexity=volume’ conjecture using Lorentzian flows — timelike vector fields whose minimum flux through a boundary subregion is equal to the volume of the homologous maximal bulk Cauchy slice. By the nesting of Lorentzian flows, holographic complexity is shown to obey a number of properties. Particularly, the rate of complexity is bounded below by conditional complexity, describing a multi-step optimization with intermediate and final target states. We provide multiple explicit geometric realizations of Lorentzian flows in AdS backgrounds, including their time-dependence and behavior near the singularity in a black hole interior. Conceptually, discretized flows are interpreted as Lorentzian threads or ‘gatelines’. Upon selecting a reference state, complexity thence counts the minimum number of gatelines needed to prepare a target state described by a tensor network discretizing the maximal volume slice, matching its quantum information theoretic definition. We point out that suboptimal tensor networks are important to fully characterize the state, leading us to propose a refined notion of complexity as an ensemble average. The bulk symplectic potential provides a specific ‘canonical’ thread configuration characterizing perturbations around arbitrary CFT states. Consistency of this solution requires the bulk satisfy the linearized Einstein’s equations, which are shown to be equivalent to the holographic first law of complexity, thereby advocating for a principle of ‘spacetime complexity’. Lastly, we argue Lorentzian threads provide a notion of emergent time. This article is an expanded and detailed version of [1], including several new results.

Lorentzian Threads as Gatelines and Holographic Complexity.

The continuous min flow-max cut principle is used to reformulate the "complexity=volume" conjecture using Lorentzian flows-divergenceless norm-bounded timelike vector fields whose minimum flux through a boundary subregion is equal to the volume of the homologous maximal bulk Cauchy slice. The nesting property is used to show the rate of complexity is bounded below by "conditional complexity," describing a multistep optimization with intermediate and final target states. Conceptually, discretized Lorentzian flows are interpreted in terms of threads or gatelines such that complexity is equal to the minimum number of gatelines used to prepare a conformal field theory (CFT) state by an optimal tensor network (TN) discretizing the state. We propose a refined measure of complexity, capturing the role of suboptimal TNs, as an ensemble average. The bulk symplectic potential provides a "canonical" thread configuration characterizing perturbations around arbitrary CFT states. Its consistency requires the bulk to obey linearized Einstein's equations, which are shown to be equivalent to the holographic first law of complexity, thereby advocating a notion of "spacetime complexity."

The Effects of Different Screw Combinations on the Initial Stability of Ankle Arthrodesis.

The literature is scanty regarding the biomechanical effects of different thread configurations on the initial stability of ankle arthrodesis. This study aims to compare the initial stability of tibiotalar fusion site in ankle arthrodesis using cannulated screws with different thread designs. We biomechanically tested under cyclic loading the effects of different screw combinations on the initial stability of ankle arthrodesis. A total of 28 synthetic ankle models were divided into four groups: two partially threaded cancellous screws (group A), partially and fully threaded cancellous screws (group B), a partially threaded cancellous screw with a headless compression screw (group C), and a fully threaded cancellous screw and a headless compression screw (group D). Biomechanical variables including ultimate failure load, initial stiffness, ultimate stiffness, and failure angulation were analyzed. There were no differences in any of the biomechanical variables among the four groups (P = .41 for ultimate failure load, P = .079 for initial stiffness, P = .084 for ultimate stiffness, and P = .937 for failure angulation). Combinations of different cannulated screws showed similar results in terms of the stability and stiffness of the tibiotalar fusion site.

Deriving the PEE proposal from the locking bit thread configuration

In the holographic framework, we argue that the partial entanglement entropy (PEE) can be explicitly interpreted as the component flow flux in a locking bit thread configuration. By applying the locking theorem of bit threads, and constructing a concrete locking scheme, we obtain a set of uniquely determined component flow fluxes from this viewpoint, and successfully derive the PEE proposal and its generalized version in the multipartite cases. Moreover, from this perspective of bit threads, we also present a coherent explanation for the coincidence between the BPE (balanced partial entanglement)/EWCS (entanglement wedge cross section) duality proposed recently and the EoP (entanglement of purification)/EWCS duality. We also discuss the issues implied by this coincident between the idea of the PEE and the picture of locking thread configuration.