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The interaction of light with solids can be dramatically enhanced owing to electron-photon momentum matching. This mechanism manifests when light scattering from nanometer-sized clusters including a specific case of self-assembled nanostructures that form a long-range translational order but local disorder (crystal-liquid duality). In this paper, a new strategy based on both cases for the light-matter-interaction enhancement in a direct bandgap semiconductor - lead halide perovskite CsPbBr3 - by using electric pulse-driven structural disorder, is addressed. The disordered state allows the generation of confined photons, and the formation of an electronic continuum of static/dynamic defect states across the forbidden gap (Urbach bridge). Both mechanisms underlie photon-momentum-enabled electronic Raman scattering (ERS) and single-photon anti-Stokes photoluminescence (PL) under sub-band pump. PL/ERS blinking is discussed to be associated with thermal fluctuations of cross-linked [PbBr6]4- octahedra. Time-delayed synchronization of PL/ERS blinking causes enhanced spontaneous emission at room temperature. These findings indicate the role of photon momentum in enhanced light-matter interactions in disordered and nanostructured solids.
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In this paper, a novel fractional-order stochastic gradient descent with momentum and energy (FOSGDME) approach is proposed. Specifically, to address the challenge of converging to a real extreme point encountered by the existing fractional gradient algorithms, a novel fractional-order stochastic gradient descent (FOSGD) method is presented by modifying the definition of the Caputo fractional-order derivative. A FOSGD with moment (FOSGDM) is established by incorporating momentum information to accelerate the convergence speed and accuracy further. In addition, to improve the robustness and accuracy, a FOSGD with moment and energy is established by further introducing energy formation. The extensive experimental results on the image classification CIFAR-10 dataset obtained with ResNet and DenseNet demonstrate that the proposed FOSGD, FOSGDM and FOSGDME algorithms are superior to the integer order optimization algorithms, and achieve state-of-the-art performance.
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The contribution of body part angular momentum (BPAM) to whole body angular momentum (WBAM) in the frontal plane during walking differs across age groups. We investigated age related differences in BPAM and WBAM during walking. We used marker coordinate data from a publicly available database for 54 individuals aged 20-30 years and 78 aged 60-70 years. Angular momentum in the frontal plane was calculated as the sum of the translational component and the rotational component for each segment. The angular momentum of each segment was categorized into five BPAM: right and left lower limbs (foot, shank, and thigh), right and left arms (hand, forearm, and upper arm), and torso (head, thorax, and pelvis). BPAM at WBAM peak frames during stride cycles was compared between older and younger adults. The peak WBAM, angular momentum of the stance-and swing side upper limbs, and torso in older adults was significantly larger than that in younger adults, with increases of 74.6% in the stance-side upper limb, 127.5% in the swing-side upper limb, and 30.9% in the torso. These results suggest that interventions aimed at improving torso control could decrease the amplitude of WBAM in the frontal plane in older adults.
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Tronco , Caminhada , Humanos , Caminhada/fisiologia , Idoso , Pessoa de Meia-Idade , Adulto , Masculino , Feminino , Fenômenos Biomecânicos , Adulto Jovem , Tronco/fisiologia , Fatores Etários , Marcha/fisiologia , Envelhecimento/fisiologiaRESUMO
We investigate the use of various momentum methods in combination with an ensemble approximation of gradients, for accelerated optimization. Although momentum gradient descent methods are popular in machine learning, it is unclear how they perform when applied to time-consuming dynamic problems such as production optimization for petroleum reservoir management. Four different momentum methods are extensively tested on a reservoir test case in one deterministic and one robust setting. The numerical experiments show that momentum strategies yield, on average, a higher net present value with fewer simulations needed.
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In the epi-cadmium neutron induced fission of 235U, independent isomeric yield ratios (IR) of fission products 130,132Sb, 131,133Te, 134,136I, 135Xe and 138Cs have been measured by using an off-line gamma-ray spectrometric technique. The average neutron energy of the epi-cadmium reactor neutron spectrum is 1.9 MeV. From the IR values, the root mean square fragment angular momenta (JRMS) were deduced by using spin dependent statistical model analysis. The IR and JRMS values of considered fission products in the epi-cadmium neutron induced fission of 235U were compared with the literature data in the thermal neutron induced fission of 235U to examine the influence of excitation energy on nuclear structure effect.
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Acoustic manipulation has emerged as a valuable tool for precision controls and dynamic programming of cells and particles. However, conventional acoustic manipulation approaches lack the finesse necessary to form intricate, configurable, continuous, and 3D patterning of particles. Here, this study reports acoustography by Beam Engineering and Acoustic Control Node (BEACON), which delivers intricate, configurable patterns by guiding particles along custom paths with independent phase modulation. Leveraging analytical methods of orbital angular momentum beam via iterative Wirtinger hologram algorithm, this study accomplish acoustography by facilitating orbital angular momentum traps, enabling continuous 2D and 3D acoustic manipulation of microparticles in any desired geometry, with phase modulation independent of intensity. Utilizing on-chip acoustography, the BEACON platform markedly increases the space-bandwidth product to 31 000 while attaining an enhanced resolution with a pixel size of ≈25 µm, surpassing the typical resolution of over 200 µm in previous holographic particle manipulation methods. The capabilities of BEACON are demonstrated in creating intricate triple helical tracing structures using microdroplets (20 µm in diameter) and those carrying DNA to validate the effectiveness of the acoustography and phase control methods. This study offers new particle manipulation opportunities, paving the way for next-generation biomedical systems and the future of contact-free precision manufacturing.
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INTRODUCTION: Diagnostic errors in emergency departments (ED) are a significant concern and exacerbated by cognitive biases during patient handoffs. The timing and accuracy of disclosing working diagnoses during these handoffs potentially influence diagnostic decisions, yet empirical evidence remains limited. MATERIALS AND METHODS: This parallel, quasi-experimental study involved 40 interns from Japanese teaching hospitals, randomly assigned to control or intervention groups. Each group reviewed eight audio-recorded patient handoff scenarios where working diagnoses were disclosed at the start (control) or end (intervention). Four cases presented correct diagnoses, while four featured incorrect ones. The main measure was diagnostic error rate, calculated as the proportion of incorrect post-handoff responses to total questions asked. RESULTS: No significant difference in diagnostic error rates emerged between the control (39.4â¯%, 63/160) and intervention (38.8â¯%, 62/160) groups (point estimate -0.6â¯%; 95â¯% CI: -11.3-10.1â¯%, p=0.91). However, a substantial difference was evident between diagnostic errors after correct (20.6â¯%, 33/160) and incorrect (57.5â¯%, 92/160) working diagnoses presented (point estimate: 36.9â¯%; 95â¯% CI: 27.0-46.8â¯%, p<0.001). Diagnostic momentum accounted for 52â¯% (48/92) of errors under incorrect diagnoses. DISCUSSION: While the timing of working diagnosis disclosure did not significantly alter diagnostic accuracy during ED handoffs, exposure to incorrect diagnoses markedly increased error rates. These findings underscore the imperative to refine diagnostic skills and reconsider ED handoff protocols to mitigate cognitive biases and optimize patient care outcomes.
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Silicate glasses containing silicon, sodium, phosphorous, and calcium have the ability to promote bone regeneration and biodegrade as new tissue is generated. Recently, it has been suggested that adding SrO can benefit tissue growth and silicate glass dissolution. Motivated by these recent developments, the effect of SrO/CaO-CaO/SrO substitution on the local structure and dynamics of Si-Na-P-Ca-O oxide glasses has been studied in this work. Differential thermal analysis has been performed to determine the thermal stability of the glasses after the addition of strontium. The local structure has been studied by neutron diffraction augmented by Reverse Monte Carlo simulation, and the local dynamics by neutron Compton scattering and Raman spectroscopy. Differential thermal analysis has shown that SrO-containing glasses have lower glass transition, melting, and crystallisation temperatures. Moreover, the addition of the Sr2+ ions decreased the thermal stability of the glass structure. The total neutron diffraction augmented by the RMC simulation revealed that Sr played a similar role as Ca in the glass structure when substituted on a molar basis. The bond length and the coordination number distributions of the network modifiers and network formers did not change when SrO (x = 0.125, 0.25) was substituted for CaO (25-x). However, the network connectivity increased in glass with 12.5 mol% CaO due to the increased length of the Si-O-Si interconnected chain. The analysis of Raman spectra revealed that substituting CaO with SrO in the glass structure dramatically enhances the intensity of the high-frequency band of 1110-2000 cm-1. For all glasses under investigation, the changes in the relative intensities of Raman bands and the distributions of the bond lengths and coordination numbers upon the SrO substitution were correlated with the values of the widths of nuclear momentum distributions of Si, Na, P, Ca, O, and Sr. The widths of nuclear momentum distributions were observed to soften compared to the values observed and simulated in their parent metal-oxide crystals. The widths of nuclear momentum distributions, obtained from fitting the experimental data to neutron Compton spectra, were related to the amount of disorder of effective force constants acting on individual atomic species in the glasses.
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The heat and momentum transfer of tomato puree through a concentric-tube heat exchanger over a range of generalized Reynolds number (0.05 < Re < 66.5) was experimentally and numerically analyzed. Thermophysical and rheological properties of tomato puree (12°Brix) were measured from 20 to 60°C. The velocity, pressure, and temperature were calculated using the computational fluid dynamics (CFD) software FLUENTTM with temperature-dependent transport properties. The thermal operation of the concentric-tube exchanger was satisfactorily predicted using CFD, indicating accurate measurement of tomato puree properties with temperature variations. A concordance was found between the calculated Fanning friction factor and generalized Reynolds with the experimental correlation. A modified Sieder-Tate correlation was established, which allows properly expressing the Nusselt number as a function of the Peclet number. Simple correlations for the mechanical work and the heat transfer rate as a function of the volumetric flow rate were derived. The thermal efficiency was high at low puree flow rates but decreased with higher rates. However, at high flow rates, ceased its decline, instead showing a slight improvement. The analysis confirmed higher heat transfer rates in the concentric-tube heat exchanger compared to a plain tube at low puree flow rates. The results offer valuable insights for assessing diverse operational conditions in dairy, beverage, sauce, and concentrated food industries. Additionally, they also enhance the analysis and design of concentric-tube heat exchangers. PRACTICAL APPLICATION: The knowledge of the rheological and hydrodynamical behavior of fluids in concentric-tube heat exchangers allows to explore a set of different operating conditions to improve the yield and effectiveness on the system heating/cooling design.
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While walking, ground reaction forces point from the centre of pressure to the neighbourhood of a focal point, namely the virtual pivot point (VPP), that adjusts angular momentum around the centre of mass (CoM). This study explores how age and speed affect the VPP quality and position during walking. Analysing an experimental dataset reveals high quality of the VPP in the sagittal plane for both young and elderly groups, regardless of speed. However, in the frontal plane, the VPP quality decreases with increasing speed, with elderly participants exhibiting significantly lower quality. Although not a direct measure of balance, VPP quality reflects changes in whole-body angular momentum owing to ageing and speed. Additionally, a template model is used to reproduce the VPP quality and position trends observed in the experiment. Simulation results highlight the sensitivity of VPP quality to leg force feedback and show that changing VPP height has minimal effect on gait speed. Furthermore, energy redistribution occurs through increased hip extension and leg damping, associated with a greater horizontal VPP distance from the CoM, observed in elderly walking. This study shows promise for analysing gait based on VPP, potentially aiding clinical interventions and supporting locomotion in the elderly.
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Internal hernias account for a minority of cases of intestinal obstruction. Within this group, internal hernias through the foramen of Winslow (FW) are an even rarer subcategory with a paucity of cases reported in the literature. We present a case of a 48-year-old female presenting with right upper quadrant pain akin to biliary colic with sonographic evidence of cholelithiasis. Her symptoms swiftly worsened, and she re-presented with symptoms of bowel obstruction. She was subsequently found to have a caecal volvulus herniating through the FW on computed tomography (CT). She underwent an emergency laparotomy to reduce the hernia and prevent further recurrence, which highlighted the importance of a comprehensive history and the increasing role of cross-sectional imaging in emergency surgery.
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We explore the propagation of structured vortex laser beams-shaped light carrying orbital angular momentum (OAM)-through complex multiple scattering medium. These structured vortex beams consist of a spin component, determined by the polarization of electromagnetic fields, and an orbital component, arising from their spatial structure. Although both spin and orbital angular momenta are conserved when shaped light propagates through a homogeneous, low-scattering medium, we investigate the conservation of these angular momenta during the propagation of Laguerre-Gaussian (LG) beams with varying topological charges through a turbid multiple scattering environment. Our findings demonstrate that the OAM of the LG beam is preserved, exhibiting a distinct phase shift indicative of the 'twist of light' through the turbid medium. This preservation of OAM within such environments is confirmed by in-house developed Monte Carlo simulations, showing strong agreement with experimental studies. Our results suggest exciting prospects for leveraging OAM in sensing applications, opening avenues for groundbreaking fundamental research and practical applications in optical communications and remote sensing.
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The structural symmetry of solids plays an important role in defining their linear and nonlinear optical properties. The quest for versatile, cost-effective, large-scale, and defect-free approaches and materials platforms for tailoring structural and optical properties on demand is underway since decades. A self-assembled spherulite material comprised of synthesized molecules with large dipole moments aligned azimuthally, forming a vortex polarity with spontaneously broken symmetry, is experimentally demonstrated. This unique self-assembled structure enables new linear and nonlinear light-matter interactions, including generating optical vortex beams with complex spin states and on-demand topological charges at the fundamental, doubled, and tripled frequencies. This work will likely enable numerous applications in areas such as high-dimensional quantum information processing with large capacity and high security, spatiotemporal optical vortices, and a novel optical manipulation and trapping platform.
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This paper introduces the flexible control and trajectory planning medical two-arm surgical robots, and employs effective collision detection methods to ensure the safety and precision during tasks. Firstly, the DH method is employed to establish relative rotation matrices between coordinate systems, determining the relative relationships of each joint link. A neural network based on a multilayer perceptron is proposed to solve FKP problem in real time. Secondly, a universal interpolator based on Non-Uniform Rational B-Splines (NURBS) is developed, capable of handling any geometric shape to ensure smooth and flexible motion trajectories. Finally, we developed a generalized momentum observer to detect external collisions, eliminating the need for external sensors and thereby reducing mechanical complexity and cost. The experiments verify the effectiveness of the kinematics solution and trajectory planning, demonstrating that the improved momentum torque observer can significantly reduce system overshoot, enabling the two-arm surgical robot to perform precise and safe surgical tasks under algorithmic guidance.
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Background: In volleyball, the jump serve is a crucial and commonly used serving technique. Nonetheless, the angular momentum developed during the jump serve remains unexplored. The objectives of the current study were to determine the angular momentum manifesting during the airborne phase of the jump serve and to analyse the correlations between the angular momentum variables and arm swing speed. Methods: Three-dimensional coordinate data were obtained during the jump serves of 17 professional male volleyball players. Correlation and linear regression analyses were used to identify the angular momentum variables linked to the arm swing speed at ball impact (BI). Results: The arm swing speed at BI exhibited significant correlations with the peak angular momentum of the attack arm (r = 0.551, p = 0.024), non-attack arm (r = 0.608, p = 0.011), non-attack leg (r = -0.516, p = 0.034), forearm (r = 0.527, p = 0.032), and hand (r = 0.824, p < 0.001). A stepwise regression model (R2 = 0.35, p = 0.043) predicted arm swing speed based on the peak angular momentum of the non-attack leg, forearm, and hand. Conclusions: The study results suggest that during the arm-acceleration phase, (1) increasing angular momentum with the non-attack leg helps maintain aerial body balance, thereby enhancing arm swing execution, and (2) controlling the magnitude and timing of the force exerted by the elbow and wrist is crucial for effectively transmitting angular momentum, contributing to an increase in arm swing speed.
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Braço , Voleibol , Humanos , Voleibol/fisiologia , Masculino , Fenômenos Biomecânicos/fisiologia , Braço/fisiologia , Adulto Jovem , Movimento/fisiologia , Adulto , Desempenho Atlético/fisiologiaRESUMO
Chiral light emission plays a key role in sensing, tomography, quantum communication, among others. Whereas, achieving highly pure, tunable chirality emission across a broad spectrum currently presents significant challenges. Free-electron radiation emerges as a promising solution to surpass these barriers, especially in hard-to-reach regimes. Here, chiral free-electron radiation is presented by exploiting the spin-momentum locking (SML) property of spoof surface plasmons (SSPs). When the phase velocity of free electrons matches that of the SSPs, the SSPs can be excited. By implementing wavenumber compensation through perturbations, the confined SSPs are transformed into free-space free-electron radiation. Owing to the law of angular momentum conservation, this process converts the transverse spin angular momentum of SSPs into the longitudinal spin angular momentum of free-electron radiation during the process, producing pure, tunable, and chiral free-electron radiation across a broad spectrum. This method achieves an optimal degree of circular polarization approaching -1. The innovative methodology can be adapted to SML-enabled guided states or silicon photonics platforms, offering new avenues for achieving chiral emission.
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Accelerating a free electron to high-energy forms the basis for studying particle and nuclear physics. Here it is shown that the wave function of such an energetic electron can be further manipulated with the femtosecond intense lasers. During the scattering between a high-energy electron and a circularly polarized laser pulse, a regime is found where the enormous spin angular momenta of laser photons can be efficiently transferred to the electron orbital angular momentum (OAM). The wave function of the scattered electron is twisted from its initial plane-wave state to the quantum vortex state. Nonlinear quantum electrodynamics (QED) theory suggests that the GeV-level electrons acquire average intrinsic OAM beyond ⟨ l ⟩ â¼ 100 â $\langle l \rangle \sim 100\hbar $ at laser intensities of 1020 W cm-2 with linear scaling. These electrons emit γ-photons with two-peak spectrum, which sets them apart from the ordinary electrons. The findings demonstrate a proficient method for generating relativistic leptons with the vortex wave functions based on existing laser technology, thereby fostering a novel source for particle and nuclear physics.
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The changes in brain function in response to mild head injury are usually subtle and go undetected. Physiological biomarkers would aid in the early diagnosis of mild head injury. In this study we used hypercapnia to follow changes in cerebral vascular reactivity after repetitive mild head injury. We hypothesized head injury would reduce vascular reactivity. Rats were maintained on a reverse light-dark cycle and head impacted daily at 24 h intervals over three days. All head impacts were delivered while rats were fully awake under red light illumination. There was no neuroradiological evidence of brain damage. After the 3rd impact rats were exposed to 5% CO2 and imaged for changes in BOLD signal. All imaging was done while rats were awake without the confound of anesthesia. The data were registered to a 3D MRI rat atlas with 171 segmented brain areas providing site specific information on vascular reactivity. The changes in vascular reactivity were not uniform across the brain. The prefrontal cortex, somatosensory cortex and basal ganglia showed the hypothesized decrease in vascular reactivity while the cerebellum, thalamus, brainstem, and olfactory system showed an increase in BOLD signal to hypercapnia.
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Modelos Animais de Doenças , Hipercapnia , Imageamento por Ressonância Magnética , Ratos Sprague-Dawley , Vigília , Animais , Masculino , Ratos , Vigília/fisiologia , Hipercapnia/fisiopatologia , Encéfalo/fisiopatologia , Encéfalo/diagnóstico por imagem , Circulação Cerebrovascular/fisiologia , Oxigênio/sangueRESUMO
BACKGROUND: Previous research has suggested that spatiotemporal step parameters differ between settings; however, it remains unclear how different settings influence walking balance control. RESEARCH QUESTION: How do settings and sex influence walking balance control during walking at different speeds for young adults? METHODS: Forty-two adults (21 male (23 ± 4 years), 21 female (24 ± 5 years)) completed overground walking trials in four settings: laboratory (10â¯m), hallway, indoor open, and outdoor pathway (all 20â¯m) at three self-selected speeds (slow, preferred, fast) following verbal instructions. Participants wore 17 inertial sensors (Xsens Awinda, Movella, Henderson, NV) to capture total body kinematics. The number of included strides was matched across all conditions, with six strides included in each condition for all participants. Medial-lateral and anterior-posterior total body angular momentum range over each stride was calculated (HML range and HAP range). Setting × speed × sex mixed factorial analysis of variance with repeated measures on setting and speed were used for statistical analysis (α =.05). RESULTS: Significant setting × speed interactions (p <.001) were present for both outcomes. HML range was greater in the laboratory and hallway compared to the indoor open and outdoor pathway settings for slow walking speed only. HAP range was lower in the outdoor pathway compared to all indoor settings at slow and preferred walking speeds. Differences in HAP range between settings was more pronounced at the slow speed condition. Across setting and speed conditions, HML range was greater for males compared to females. SIGNIFICANCE: Young adults may alter their balance control strategy depending on the setting (laboratory, indoor open and outdoor pathway), particularly at slow speeds. Researchers and clinicians are cautioned not to assume walking in laboratory settings reflects walking in all settings nor that males and females can be examined as a single group.
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Heart failure (HF) remains a public health concern affecting millions of individuals worldwide. Despite recent advances in device-related therapies, the prognosis for patients with chronic HF remains poor with significant long-term risk of morbidity and mortality. Left ventricular assist devices (LVADs) have transformed the landscape of advanced HF management, offering circulatory support as destination therapy or as a bridge for heart transplantation. Among the latest generation of LVADs, the HeartMate 3 has gained popularity due to improved clinical outcomes and lower risk of serious adverse events when compared with previous similar devices. The ELEVATE (Evaluating the HeartMate 3 with Full MagLev Technology in a Post-Market Approval Setting) Registry and the MOMENTUM 3 (Multicenter Study of MagLev Technology in Patients Undergoing Mechanical Circulatory Support Therapy with HeartMate 3) trial represent landmark investigations into the performance and comparative effectiveness of the HeartMate 3 LVAD. This review provides a comprehensive synthesis of the safety and efficacy of the 2-year and 5-year HeartMate LVAD outcomes, highlighting key findings, methodological considerations, implications for clinical practice, and future directions.