Search Results (1,574)

The fine-structure constant is an empirical boundary datum of quantum electrodynamics (QED), not a value derived by the Standard Model. We give a conditional structural derivation in which its inverse is matched to the response capacity of a neutral codimension-two holonomy defect. The Indefinite Reconstruction Stability Principle and the topology of a punctured transverse space select codimension two and an integer winding group $\mathbb{Z}$. Phase and spin read-outs are represented by native norm-one groups $\mathrm{U}\left(1\right)$ and $\mathrm{SU}\left(2\right)$. Preserving their algebraic identities and multiplicative norms fixes the measures $2\pi$ and $2{\pi }^2$. Their three nonempty exposures have total capacity $\Omega =4{\pi }^3+{\pi }^2+\pi$. Four first-interface roles and one protected identity select $\mathbb{Z}/5\mathbb{Z}$; its 24 nonzero outgoing–returning state pairs form one symmetry orbit, fixing the first correction. At later resolutions, a separately declared asymmetric complete-source/exposed-target transfer rule—not the Chinese remainder theorem used only for common refinement—fixes the coefficients by unit counting without assuming composite-level transitivity. With a declared paired-interface grading rule, they yield an absolutely convergent odd-power tower with an exact logarithmic sum. A separate low-energy QED matching postulate identifies the structural response with the renormalized zero-momentum Maxwell coefficient, giving $\alpha {\left(0\right)}^{-1}=137.035999176142$, $0.041$ standard deviations below the 2022 CODATA value. No numerical coefficient is adjusted once the declared read-out, counting, transfer, grading, and matching assumptions are fixed. The construction does not derive QED dynamics or the running coupling. Full article

Parkinson’s disease (PD) is associated with alterations in gait symmetry and plantar loading that can be examined using vertical ground reaction force (VGRF) recordings. This study presents a confidence-stratified, physiology-anchored multiple-instance learning framework with concept-bottleneck-inspired pathways (implementation identifier: DRO-PAS-MIL-CBM; hereafter, PAS-MIL) for retrospective session-level PD-versus-control classification. Each gait session is represented as a bag of temporal windows. Eight predefined bilateral signal descriptors are combined with eight learned latent temporal dimensions, aggregated through attention-based pooling, and processed by concept-guided, prototype, anchor-only, and static-feature expert pathways. The evaluation used five-fold person-grouped cross-validation on 306 sessions from 165 participants in the PhysioNet Gait in Parkinson’s Disease database.Inner person-grouped out-of-fold ExtraTrees probabilities were used to construct the confidence strata and distillation targets. PAS-MIL achieved a pooled session-level area under the receiver operating characteristic curve of 0.771, average precision of 0.890, and a mean fold AUC of $0.826\pm 0.041$. Relevance analysis identified C05 (asymmetry variability) and C08 (bilateral change mismatch) as the highest-weighted predefined physiological anchor descriptors. Protocol-stratified sensitivity analysis showed variation across the three source sub-studies, with AUCs ranging from 0.740 to 0.790. Probability calibration remained suboptimal after temperature scaling (mean per-fold ECE, $0.291\pm 0.042$). The results demonstrate the feasibility of integrating physiology-informed descriptors, temporal representation learning, and session-level aggregation. The study is a retrospective proof of concept and does not establish external robustness or clinical deployment readiness. Full article

In guided-wave stimulated Brillouin scattering (SBS), the opto-mechanical coupling strength is determined by the spatial overlap of optical and elastic fields, fundamentally constrained by symmetry. Conventional analyses based on ordinary point groups assume that fields share the waveguide’s symmetry, which is valid for standing-wave modes with zero longitudinal wavenumber. However, in waveguides with longitudinal-axis-reversing operations, such operations flip the wavenumber sign for traveling-wave modes, making the conventional framework insufficient—a limitation not addressed before. Here, we introduce the type-III Shubnikov (magnetic) point groups, combining time reversal with axis-reversing spatial operations, and establish a co-representation theory for such traveling-wave modes. We prove that these modes obey a conjugate symmetry derived from the antiunitary elements of the magnetic point group. From this, we derive a general selection rule for backward SBS: if the waveguide possesses only one nontrivial axis-reversing operation (and no other independent symmetry), the conjugate symmetry allows the coupling to be nonzero. Numerical validations on single-crystal lithium niobate, fused silica, and single-crystal silicon waveguides of a trapezoidal cross-section confirm the predicted conjugate symmetry and show that materials with lower intrinsic symmetry more favorably realize such symmetry-enabled backward SBS. This work represents a systematic introduction of magnetic group theory to nonmagnetic waveguides, offering new insights for material selection and coupling control in guided-wave SBS. Full article

Three layered rare-earth hydrogenselenite–selenite hydrates, Ln(HSeO₃)(SeO₃)·2H₂O (Ln = Yb, Dy, Eu), were synthesized under hydrothermal conditions and systematically characterized. Single-crystal and powder X-ray diffraction show that the compounds are isostructural and crystallize in the non-centrosymmetric orthorhombic Sohncke space group P2₁2₁2₁, featuring LnO₈ polyhedra and SeO₃/HSeO₃ units assembled into hydrogen-bonded layered frameworks. Two-component inversion-twin refinements gave Flack x values of 0.06(4), 0.27(3), and 0.22(3) for the Yb-, Dy-, and Eu-containing crystals, respectively; the Yb crystal is dominated by one inversion domain, whereas the Dy and Eu crystals contain appreciable inverted-domain fractions. Because L/D/DL descriptors conventionally refer to the absolute configuration of chiral molecular entities, they are not assigned to these extended inorganic frameworks. Under the present achiral synthesis conditions, crystals dominated by the opposite, inversion-related framework hand cannot be excluded. Photoluminescence measurements reveal characteristic Dy³⁺ and Eu³⁺ emissions, while the Yb analogue exhibits a broad visible band tentatively related to host-framework states. Magnetic measurements show no long-range ordering above 2 K; the Yb and Dy phases display dominant antiferromagnetic correlations, whereas the Eu phase is governed mainly by Van Vleck paramagnetism. These results identify Ln(HSeO₃)(SeO₃)·2H₂O as a layered Sohncke-symmetry platform with lanthanide-dependent optical and magnetic behavior. The observed lanthanide emissions and non-centrosymmetric framework suggest prospective photonic and nonlinear-optical applications, although device-level performance remains to be established. Full article

Background and Objectives: Presurgical infant orthopedics aims to reduce cleft severity and facilitate primary surgical repair during the early neonatal period, when increased tissue plasticity enhances molding. Nasoalveolar molding is widely used but requires intraoral appliances, laboratory support, specialized training, and frequent follow-up visits, which may limit accessibility and adherence. This case series reports the clinical application of presurgical lip–alveolus–nose approximation (PLANA), an extraoral technique for early presurgical cleft management, and describes the clinical changes observed during treatment in four infants. Materials and Methods: A prospective case series conducted in neonates with non-syndromic unilateral or bilateral cleft lip and/or palate referred within the first 10 days of life to the Alabama Cleft Center. Treatment consisted of a prefabricated silicone nasal aligner combined with hydrocolloid lip adhesive taping. No intraoral plates or dental impressions were used. Devices were worn 20 to 22 h daily. Follow up occurred every 2 to 4 weeks, with remote monitoring used when appropriate. Qualitative clinical observations focused on apparent changes in nasal symmetry, columellar length, septal alignment, nasal tip projection, premaxillary position, nostril dimensions, alar base width, cleft width, and lip approximation, as well as feeding tolerance, skin tolerance, and treatment adherence. These observations were assessed qualitatively through serial clinical examinations and clinical photographs; no standardized quantitative morphometric measurements were performed. Results: Four infants with complete unilateral or bilateral cleft lip and palate received PLANA treatment. Serial clinical examinations and photographs documented qualitative changes in nasolabial morphology over the course of treatment in all four patients. Qualitative clinical assessment of serial photographs and examinations suggested greater apparent nasal symmetry, apparent columellar elongation, more central-appearing nasal alignment, increased apparent nasal tip projection, apparent cleft-width reduction, and progressive lip approximation. In unilateral clefts, changes were observed in both the cleft and non-cleft nasal sides, while bilateral clefts demonstrated changes in nasal morphology bilaterally. No device-related complications or clinically significant skin intolerance were documented during the reported treatment periods. Parent-reported device wear was approximately 20–22 h per day. Conclusions: In this four-patient prospective descriptive case series, PLANA was applied clinically, with no clinically significant treatment-related complications documented during the reported treatment periods. Serial clinical observations suggested changes in nasolabial morphology during treatment. Given the small sample size, absence of a contemporaneous control group, and qualitative nature of the assessments, these findings should be interpreted as preliminary and hypothesis-generating rather than as evidence of treatment efficacy or comparative effectiveness. Larger prospective, multicenter comparative studies incorporating standardized quantitative measurements, objective adherence assessment, and long-term surgical and aesthetic outcomes are needed to evaluate the effectiveness, reproducibility, and clinical applicability of the PLANA approach. Full article

Tensegrity structures, due to their lightweight and self-equilibrating characteristics, have found extensive applications across various engineering fields. The introduction of equal cable length as an additional geometric constraint enables a high degree of geometric symmetry, resulting in uniform internal force distribution and predictable mechanical responses. However, existing stiffness matrix assembly methods predominantly rely on conventional node-element topological connectivity matrices confined to classical one-to-one force-displacement systems, struggling to exploit the geometric regularities inherent in equal-length constraints and highly symmetric configurations. To address this, the paper proposes a stiffness matrix modeling method tailored for equal-cable-length tensegrity structures within the linear stiffness framework. A generalized connectivity matrix is introduced to unify the topological description of struts and cables while integrating displacement compatibility, internal equilibrium, and geometric constraints into a cohesive algebraic system. Leveraging symmetry properties and member categorization by loading type, the method embeds equal-length and symmetry grouping information directly into assembly, significantly reducing independent variables and construction complexity. A finite element model is established for numerical implementation, and experiments on a three-bar tensegrity structure validate the theoretical model, with minor deviations confirming its reliability. Full article

To address the challenges associated with operational ventilation in high-altitude tunnels, this study investigates the distribution patterns of ventilation flow fields and optimizes the spatial layout parameters of jet fans to determine the most effective configuration. Using a case study from the Zhuohe Expressway tunnel, numerical simulations were conducted to analyze four key design parameters: the lateral clear distance (L) between two jet fans in a single group, the vertical distance (H) from the fan center to the tunnel lining, the axial distance (T) from the fan to the tunnel entrance, and the longitudinal spacing (S) between two groups of fans. The results indicate that for a single-fan group, when the parameter L is 1.25D (D is the fan diameter), pressure rise and comprehensive influence coefficients reach peak values of 20.090 Pa and 0.886, respectively. As well as the parameter H between 1.20 m and 1.25 m, the diffusion of the vertical wind field velocity is continuously reduced due to the constraint of the tunnel lining on Section BB of the tunnel fan’s symmetry axis, and the interference of the tunnel lining on the stable flow state of the fan’s outlet airflow is relatively small. Moreover, parameter T has a relatively low sensitivity impact on the increase in pressure and the variation of the influence coefficient. When the parameter T is within the range of 50 m to 100 m, the airflow at the entrance of the tunnel is smoothly connected with the airflow at the suction section of the fan. Additionally, the pressure rise and the influence coefficient increase by the parameter T. Both the fan’s pressure rise and the influence coefficient reach their maximum values when the parameter T is 100 m. Furthermore, in the case of two-fan groups, the gas is fully mixed in the tunnel when the parameter S is 150 m, and the fan pressure rise and the influence coefficient increase as well as parameter S. The gas between the two sets of fans has been fully mixed in the parameter S at 175 m, and the pressure rise and the coefficient influence reach their maximum values of 40.231 Pa and 0.887, respectively. In light of these findings, the following optimal parameters ranges are recommended for similar tunnel ventilation designs: parameter L is 1.25D for two jet fans within a single group, parameter H is between 1.20 m and 1.25 m, parameter T is 100 m from the tunnel entrance, and parameter S is between 150 m and 175 m for two groups of fans. Full article

Real-time feedback-based training has emerged as a potentially time-efficient approach for enhancing neuromuscular performance, yet evidence in youth basketball athletes remains limited. This study examined the acute and short-term effects of a five-day simulator-based neuromuscular training program incorporating real-time feedback on vertical jump performance and reactive efficiency in youth basketball players. A quasi-experimental, single-group repeated-measures design was employed, with performance assessed at three time points: pre-intervention (T1), post-intervention (T2), and 7-day follow-up (T3). Twenty-one male junior athletes (15.1 ± 0.7 years) completed five consecutive sessions on a condition simulation device (ERGOSIM), designed to enhance force control and neuromuscular coordination through real-time visual feedback. Vertical jump performance was assessed using a 15 s repeated jump test (OptoJump), including bilateral and unilateral conditions. Primary outcomes were jump height (H), mean average power (PU), and contact time (CT), analyzed via the MGM-15 method. Repeated-measures ANOVA revealed significant time effects for bilateral performance: H (F(2,40) = 16.593, p < 0.001, η²_p = 0.453), PU (F(2,40) = 19.281, p < 0.001, η²_p = 0.491), and CT (F(2,40) = 6.009, p = 0.005, η²_p = 0.231). From T1 to T3, bilateral jump height increased by 17.0%, accompanied by a 14.5% increase in average power and a 10.3% reduction in contact time. Unilateral performance improved significantly in both limbs, with progressive reduction in inter-limb asymmetry across the intervention period. Performance gains were largely maintained at T3, indicating short-term retention of neuromuscular adaptations. These findings suggest that simulator-based, feedback-driven neuromuscular training represents a time-efficient strategy for optimizing explosive performance and inter-limb symmetry within competitive microcycles although the single-group design and absence of a control group warrant cautious interpretation. Full article

The increasing complexity of cyber–physical manufacturing systems demands simulation architectures that scale with the physical plant without a proportional growth in engineering effort. This paper introduces a formal, symmetry-based framework for behavioral reuse in arbitrary cyber–physical manufacturing systems, implemented within the Siemens NX Mechatronic Concept Designer (MCD), version NX 2506, environment. Symmetry is treated rigorously, as an equivalence relation induced by a symmetry-group action over the set of plant components, and three exploitable classes are defined on this basis: structural symmetry, arising from replicated kinematic configurations; functional symmetry, arising from shared behavioral specifications across instances of a common component class; and temporal symmetry, arising from synchronized cyclic behavior across concurrent actors. From these definitions, a four-condition behavioral inheritance protocol is derived, specifying the prerequisites under which a single behavioral library template is correctly instantiated across an arbitrary number of interchangeable components. The framework is demonstrated on a production cell comprising ten conveyor sections, nine CNC machining centers (5-axis, X/Y/Z/A/B/SP), and two COMAU NJ420-3.0 manipulators—each a 6-axis articulated arm extended by an external linear rail to seven controlled axes—governed through Siemens Sinumerik RunMyRobot/Direct Control and exercised in a co-simulation environment that integrates a Create MyVirtual Machine (CMVM) Software-in-the-Loop (SiL) controller, a Simit Model-in-the-Loop (MiL) communication layer, and MCD for kinematic and behavioral emulation. Using the number of independent behavioral configuration operations as the effort metric, the symmetry-driven approach reduces machining-center configuration effort by 88.9% (from nine independent configurations to one template instantiated nine times) and robot behavioral configuration effort by 100% (both manipulators inherit from a single seven-axis library entry), while preserving full kinematic and signal-level fidelity. The inheritance mechanism is shown to tolerate heterogeneous kinematic substitution: a COMAU NJ420-3.0 may be replaced by any kinematically equivalent 6-axis manipulator in the RunMyRobot database without behavioral reconfiguration. The component and capability mapping matrix (CCMM) introduced in prior work is extended with a symmetry-annotation layer that explicitly encodes instance relationships and inheritance chains, providing a structured input to automated behavioral-deployment workflows. The results establish symmetry-based modular simulation as a principled and scalable methodology for industrial digital-twin development in multi-robot manufacturing environments. Full article

Digital innovation platform ecosystems can scale rapidly without becoming durable because broad participation does not ensure sustained value circulation. Existing models homogenize complementors, obscuring horizontal coopetition among distinct groups and its interaction with vertical governance. We examine how vertical and horizontal relations shape value-flow architecture and sustainability. Drawing on ecological symbiosis theory, we distinguish a platform orchestrator, technology-extending complementors, and service-integrating complementors. We construct an extended three-actor Lotka–Volterra model and use the Global Value-Flow Symmetry (GV) index and the continuous directional indicator ${\delta }_c$ to assess symmetry and direction. Designed for theory building rather than empirical calibration or testing, the analysis uses no empirical data and compares 35 vertical–horizontal configurations through deterministic simulation and sensitivity analysis. Results show the following: (1) Greater symmetry is associated with higher aggregate maintained output, but vertical backflow direction shapes its distribution; $\mathrm{G}\mathrm{V}$ must therefore be interpreted with ${\delta }_c$. (2) Under complementor-favoring vertical parasitism, horizontal mutualism expands complementor output but intensifies negative vertical backflow, simultaneously increasing aggregate output and reducing platform equilibrium—a cooperation paradox. (3) The same horizontal mutualism yields three focal outcomes across the examined vertical structures: Negative complementor-to-platform effects produce the cooperation paradox, absent effects produce value decoupling, and mutually positive vertical exchange produces systemic resonance. Thus, horizontal cooperation does not necessarily enhance sustainability; its effect depends on whether complementor gains feed back to support platform capability. This study advances platform-ecosystem sustainability research and offers theoretical guidance for optimizing value backflow and cooperative governance. Full article

Background/Objectives: This study aims to evaluate the pulp space morphology (PSM) of both first and second mandibular premolars in a sample of a Greek population using cone beam computed tomography (CBCT). Methods: Two hundred and ninety nine CBCTs of a Greek population were assessed to evaluate the PSM using Vertucci’s classification. CBCTs were prescribed for non-endodontic reasons. Results: In the aforementioned data set, the most common PSM was Vertucci’s 1 (V1) in all subgroups of mandibular premolars. V3 was the second most frequent PMS in the #34 group (10.67%), and it was V5 in the #35 group (3.1%), V3 in the #44 group (14%), and V8 in the #45 group (2.7%), with the rest of the morphologies being sparse. Across the four teeth, there was a statistically significant difference in Vertucci class distribution (p = 0.001). No significant difference was found between genders (p = 0.120); bilateral symmetry analysis showed high concordance for both premolars. Conclusions: Within the limitations of this study, it is concluded that the reported pulp space morphology in the mandibular premolars of a Greek sub-population sample presented as less complicated compared to other similar reports of (sub)-populations of different descent. Full article

We prove the existence and uniqueness of weak solutions to an obstacle problem for a nonlinear elliptic operator in divergence form. The variational inequality under consideration involves an integral over the domain of the Frobenius inner product of the operator $\mathcal{S}(z,\nabla u-\mathcal{O}(u\left)\right)$ with the gradient difference $\nabla (v-u)$, plus the Euclidean inner product of u and $v-u$, which is required to be nonnegative for all admissible functions v. The admissible set consists of functions in the Sobolev space $W^{1,2}(\mathrm{\Omega };{\mathbb{R}}^m)$ with prescribed Dirichlet boundary trace and lying above a given obstacle $\psi$ almost everywhere. The obstacle condition $v\ge \psi$ a.e. models a lower bound constraint (e.g., a membrane or a displacement limit) that the admissible functions must respect, while the boundary value $\delta$ prescribes the Dirichlet data. The principal part contains a solution-dependent shift $\mathcal{O}\left(u\right)$, which is Lipschitz continuous, while $\mathcal{S}$ is assumed to be globally Lipschitz and strongly monotone with respect to equal shifts, with quadratic growth and coercivity. This structural framework can be interpreted in terms of symmetry: the strong monotonicity condition expresses a quantitative symmetry property of $\mathcal{S}$ with respect to equal shifts, and the shift $\mathcal{O}\left(u\right)$ introduces a symmetry-breaking coupling. The smallness condition ensures that this asymmetry remains under control. However, we do not pursue a full group-invariance or Lie-symmetry analysis; the symmetry perspective is used here as a heuristic and interpretative tool. The main difficulty lies in the mismatch of shifts when comparing two admissible functions. This is resolved by a three-term decomposition of the monotonicity estimate, combined with Young’s inequality and Poincaré’s inequality, under the smallness condition that the product of the Lipschitz constant of $\mathcal{S}$, the Lipschitz constant of $\mathcal{O}$, and the Poincaré constant is bounded above by one quarter of the strong monotonicity modulus. Existence follows from the Kinderlehrer–Stampacchia theorem; uniqueness is obtained from the same decomposition. The result unifies and extends previous contributions that treated either the lower-order term or the shift coupling separately, and it does so within a unified quadratic framework that avoids the technical overhead of variable exponents and Young measures. Full article

Before failures are known, an after-sales provider must decide where to open service centers, how to staff and cross-train technicians, how much spare-part throughput to reserve, and how much service capacity to keep in-house. Two features of this planning problem require separate attention. Technicians with the same primary skill can be relabeled without changing the network, whereas conservative service-time reservations can make in-house capacity appear smaller and increase outsourcing. We study these issues with a two-stage stochastic mixed-integer program in which each demand scenario is covered by reserved in-house bundles or by outsourcing. For homogeneous primary-skill pools, we identify the technician-relabeling group and show that a simple hiring-order rule preserves the optimal objective while removing only the active/inactive selection symmetry. The computational study uses a frozen campaign of 113 MIP runs in IBM ILOG CPLEX Optimization Studio 22.1 (64-bit). It retains six valid censored observations, repeats four representative Size-2 instances under four categorical solver seeds, and audits 54 designs with exact service times for $\rho \in \{0,0.5,1\}$. All 113 MIP rows and all 54 audits pass the registered structural checks, and 107 MIPs reach their size-specific target. The hiring-order rule is not a general accelerator. Its median PAR10 ratios (on/off) are 1.231, 0.885, and 0.832 for Sizes 1–3, and the direction of the effect changes across solver seeds for three of the four Size-2 diagnostic instances. Automatic solver symmetry gives a Size-2 median ratio of 0.861, although the bootstrap interval extends to 1.024; the Size-3 result is mixed. Stronger reservation protection increases total cost and reduces exact-time overload. The Size-3 minus Size-1 difference in outsourcing cost share is uncertain at $\rho =0$, but positive at $\rho =0.5$ and $\rho =1$. The group-theoretic tools are classical. The contribution lies in certifying their role in this after-sales model and evaluating them with explicit treatment of variability and censoring. Solver-side symmetry handling is the tested default, the model-side rule is cost-preserving but its computational effect is conditional, and outsourcing results should be interpreted together with reservation reliability. Full article

The spontaneous emergence of macroscopic order in driven, far-from-equilibrium complex fluids lacks a generalized framework capable of bridging continuous and discrete symmetry-breaking transitions. In this study, we propose a non-equilibrium phenomenological framework that synthesizes irreversible thermodynamics, coupled Landau–de Gennes potential expansions, and active hydrodynamics. The formulation employs a single tensorial order parameter, a nonlinear state-dependent jamming mobility closure, and a generalized set of dimensionless groups to map the non-equilibrium phase space. The model predicts a sequential symmetry-breaking cascade and reproduces the emergence of polar heliconical smectic and antiferroelectric phases in driven liquid crystals, as well as the transition from isotropic active gases to macroscopic fluid flocks and active Wigner crystals in purely repulsive Janus colloids. Across these systems, a dimensionless active torque number acts as the principal bifurcation parameter, suggesting that their macroscopic structural transitions are governed by a common balance between thermodynamic and kinematic effects rather than by the details of their microscopic interactions. Full article

The structural phase transition and associated orientational domain configurations in perovskite-type Bi_xCa_1−xMnO₃ ceramics were investigated in this work. A series of Bi_xCa_1−xMnO₃ solid solutions with x = 0.05, 0.25, 0.33 were synthesized, and Bi_0.25Ca_0.75MnO₃ with moderate orthorhombic lattice distortion was selected as the representative sample for systematic TEM characterization. Upon cooling from high temperature, the material undergoes a symmetry-lowering transition from the cubic phase with Pm$\overline{3}$m space group to the orthorhombic phase with Pnma space group. Selected-area electron diffraction (SAED) and bright-field TEM observations reveal the formation of multiple orientational domains, including both 90° and 120° configurations, within individual grains. High-resolution TEM (HRTEM) further confirms the coexistence of three distinct domain orientations at the atomic scale, with well-defined lattice fringes and domain boundaries. The reciprocal-space orientational relationships derived from SAED patterns demonstrate that these domains originate from the symmetry breaking of the parent cubic lattice during the phase transition. These findings provide direct crystallographic insight into the domain structures of BCMO, and such microstructural features are essential for revealing the structural stability and intrinsic functional behaviors of BCMO manganites. Full article