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Operation of the Collective Thomson Scattering Diagnostic in the OP2.2 Experimental Campaign of the Wendelstein7-X Stellarator
No full textIncreased muscle coactivation is linked with fast feedback control when reaching in unpredictable visual environments
No full textHumans encounter unpredictable disturbances in daily activities and sports. When encountering unpredictable physical disturbances, healthy participants increase the peak velocity of their reaching movements, muscle coactivation, and responses to sensory feedback. Emerging evidence suggests that muscle coactivation may facilitate responses to sensory feedback and may not solely increase stiffness to resist displacements. We tested this idea by examining how healthy participants alter the control of reaching movements and responses to sensory feedback when encountering variable visuomotor rotations. The rotations changed amplitude and direction between movements, creating unpredictable errors that required fast online corrections. Participants increased the peak velocity of their movements, muscle coactivation, and responses to visual and proprioceptive feedback with the variability of the visuomotor rotations. The findings highlight an increase in neural responsiveness to sensory feedback and suggest that muscle coactivation may prime the nervous system for fast responses to sensory feedback that accommodate properties of unpredictable visual environments
The effects of the 11+ Dance neuromuscular program on jump height and lower extremity biomechanics in female adolescent dancers: A non-randomized controlled pilot trial
No full textIntroduction:
Neuromuscular warm-up programs, such as FIFA 11+ were developed as early as 2006. These programs have been effective in reducing the risk of injury in female athletes by decreasing the moments surrounding the knee and improving neuromuscular control during static and dynamic movements such as jumping and landing. In addition, they have been effective for improving jump height in soccer, volleyball, and basketball.
Methods:
The effects of the 11+ Dance, a dance-specific neuromuscular warm-up program, was examined on jump height and lower extremity biomechanics during bilateral and single leg countermovement jumps in recreational dancers. Twenty female adolescents from 2 dance schools participated in this 2-centered 8-week controlled non-randomized trial. The intervention group (IG) performed the 11+ Dance program 3×/week for 8-weeks during the first 30-minute of their regularly scheduled dance classes. The control group (CG) continued with their regular dance classes routine. Ground reaction force and motion capture data were used to assess jump height and lower extremity biomechanics pre and post intervention.
Results:
Both groups statistically increased their jump height (CG: Z = 1.89-2.45, P ≤ .0167; IG: Z = 2.18-2.76, P ≤ .0167). However, no statistical between group differences were observed (Z = 0.38-1.22, P > .05). During takeoff, the IG statistically reduced peak knee extension moments (t(18) = -3.04 to -3.77, P ≤ .0167) while increasing peak hip extension moments (t(18) = 2.16-2.79, P ≤ .05) and peak hip flexion angles (t(18) = 2.68-3.72, P ≤ .0167) compared to the CG. The IG also increased the hip flexion angles compared to the CG during landing (t(18) = 2.78-5.13, P ≤ .0167) while no systematic differences were observed in all other variables of lower extremity biomechanics.
Conclusion:
The reduced joint load at the knee observed during takeoff needs further investigation. Neuromuscular training, such as the 11+ Dance, is supported by numerous quality research. Due to its simplicity, the 11+ Dance may be feasible and beneficial to complement regular warm-ups in recreational dance practice
An experimental and numerical study on the influence of inherent and induced anisotropy of a fine-grained soil
No full textThis study investigates the inherent and induced anisotropy of reconstituted kaolin samples through a series of triaxial tests in both extension and compression under various preloading conditions. Triaxial specimens were extracted from pre-consolidated cylinders either in the vertical or horizontal direction to assess anisotropic behaviour. Additionally, different preshearing steps were applied to examine their influence on inherent anisotropy. Numerical simulations using the modified Cam Clay model and the anisotropic visco-hypoplastic model failed to capture the effects of inherent anisotropy. To address this limitation, the latter model was extended by incorporating a cross-isotropic elastic stiffness formulation. By increasing the number of parameters and model complexity, this study systematically evaluates which parameters and mathematical formulations are essential for accurately describing the stiffness anisotropy of reconstituted fine-grained soils
Coordination Chemistry at the Hard–Soft Interface: Phosphine Oxide-Based Rare Earth/Transition Metal Complexes
No full textA series of monometallic Al(III), Sm(III), Dy(III), Er(III), and Yb(III) complexes, featuring tetraphenyldiphosphine monoxide (PPO) as a ligand, were synthesized and characterized. These complexes served as precursors for the construction of
heterobimetallic rare earth (RE)/transition metal (TM) assemblies. Attempts to introduce soft TMs, such as Cu(I) and Au(I), into the preformed RE−PPO synthons predominantly afforded equilibriumdriven TM-based POP species, underscoring the challenges of incorporating hard and soft metal centers directly. This observation
led to an alternative route employing a presynthesized Mo−PPO synthon, which led to the successful formation of RE/Mo heterobimetallic complexes upon addition of the RE ions. The molecular structures of both mono- and heterobimetallic species were strongly influenced by the solvent environment. Notably, reactions in dichloromethane, a noncoordinating solvent, yielded RE2 complexes featuring chloride bridges, a motif absent when coordinating solvents, such as THF or MeCN were employed. This solvent-dependent structural divergence offers a straightforward strategy for modulating the metal nuclearity within the complexes
The prevalence of Arctic multilayer clouds and their observed and modelled characteristics
No full textMultilayer clouds (MLCs) are common in the Arctic. With a limited-area setup and 2.5 km horizontal grid spacing, 32 ICON simulations from 22 August to 23 September 2020 were analysed to examine the MLC abundance and characteristics across the Arctic. The model was evaluated against observations from the MOSAiC campaign. An immersion freezing parameterisation was developed to capture the local ice-nucleating particle concentration, increasing the cloud ice number concentration by up to 16 % at temperatures above −12 °C. Overall, the model captured most cloudy events with a dry (moist) bias at lower (higher) altitudes. Simulated water paths were underestimated, roughly 3-fold for liquid water and 100-fold for frozen hydrometeors.
A 35 %–65 % MLC occurrence, smoothly distributed across the Arctic region, was simulated. Modelled MOSAiC occurrence frequencies span 42 %–76 %, compared to an observed 32 %–59 %. While large differences in the total MLC occurrence are found, two-layered systems occur with a systematic frequency of about 22 %. The sub-saturated layer between cloud layers is typically < 1 km, indicating a high likelihood of the seeder-feeder mechanism (up to 52 %), consistent with observations
Study of the over-response of radiochromic films in ultra-high dose rate and dose per pulse electron beams
No full textObjective: Many pre-clinical experiments on FLASH radiotherapy, in which biological samples are irradiated at conventional and ultra-high dose rate (UHDR), make use of radiochromic films as an absolute dose reference because their response is typically assumed to be dose rate independent. While several previous experiments confirmed this assumption, a recent study with protons found an over-response for Gafchromic EBT3 films at UHDR [doi:10.1002/mp.15526]. If EBT3 is used as a reference in FLASH experiments, the over-response could result in an underdosing that falsely appears as sparing of normal tissue.
Approach: To investigate whether the reported dose rate dependence of EBT3 can be reproduced with UHDR electron radiation as well, about 600 EBT3 samples were irradiated at the metrological linar accelerator facility at Physikalisch Technische Bundesanstalt, Braunschweig, and at the ELBE research accelerator at Helmholtz-Zentrum Dresden-Rossendorf, with different beam parameters. As dosimetric reference served a PTW flashDiamond detector which has been verified to show no deviation in the studied UHDR range as well as PTB\u27s alanine dosimetry system. In addition, several OC-1 films, which have been shown to be dose rate independent in previous studies, were irradiated together with EBT3 films.
Main results: EBT3 shows a significant over-response at ultra-high dose per pulse and intra-pulse dose rates. Up to 3 Gy per pulse no significant deviations were observed.However, for larger doses per pulse an over-response was observed that increases with dose per pulse to up to 50%. For OC-1 films no significant effects were found.
Significance: We provide evidence for the over-response of EBT3 films in UHDR electron beams. Therefore, EBT3 films should be used with caution in FLASH experiments
Novacrate v1.8.1
No full textWebbasierter interaktiver Editor für die Erstellung, Bearbeitung, Validierung und Visualisierung von Research Object Crates
Synthetic Photogrammetric Dataset for Two-Media 3D Reconstruction: Shipwreck & Terrain
No full textThe data in this repository serves as a benchmark for the development of new image-based processing pipelines that consider two separate optical media, i.e., water and air, including refraction effects. Ground truth datasets representing the true geometry form the basis of the simulation.
The synthetic scene showcases an environment constructed from both real-world laser scanning data (Jamtal glacial valley - WGS84: 46.90° N, 10.17° E) and a synthetic CAD model of a sailing ship. Although the Jamtal scan depicts a riverbed, the original data were not acquired underwater and is only synthetically flooded. The ship was chosen because of the fine details of the ropes, which are well-suited for determining the quality of the reconstruction, and larger structured areas on the hull, where classic photogrammetric methods should perform well. In the simulation dataset the entire ship is submerged and large parts of the scene are submerged (up to 8 m depth), therefore the influence of refraction must be taken into account for an accurate reconstruction of these areas. The planar water surface serves as an idealized baseline to evaluate geometric refraction correction without the interference of dynamic wave patterns.
Further technical details can be found in description_dataset.pdf
Finite element discretization of nonlinear models of ultrasound heating
No full textHeating generated by high-intensity focused ultrasound waves is central to many emerging medical applications, including non-invasive cancer therapy and targeted drug delivery. In this study, we aim to gain a fundamental understanding of numerical simulations in this context by analyzing conforming finite element approximations of the underlying nonlinear models that describe ultrasound- heat interactions. These models are based on a coupling of a nonlinear Westervelt–Kuznetsov acoustic wave equation to the heat equation with a pressure-dependent source term. A particular challenging feature of the system is that the acoustic medium parameters may depend on the temperature. The core of our new arguments in the a priori error analysis lies in devising energy estimates for the coupled semi-discrete system that can accommodate the nonlinearities present in the model. To derive them, we exploit the parabolic nature of the system thanks to the strong damping present in the acoustic component. Theoretically obtained optimal convergence rates in the energy norm are confirmed by the numerical experiments. In addition, we conduct a further numerical study of the problem, where we simulate the propagation of acoustic waves in liver tissue for an initially excited profile and under high-frequency sources