Affolter, C., Kedzierska, J., Vielma, T., Weisse, B., & Aiyangar, A. (2020). Estimating lumbar passive stiffness behaviour from subjectspecific finite element models and in vivo 6DOF kinematics. J. Biomech., 102, 11 pp.
Abstract: Passive rotational stiffness of the osseoligamentous spine is an important input parameter for estimating invivo spinal loading using musculoskeletal models. These data are typically acquired from cadaveric testing. Increasingly, they are also estimated from subjectspecific imagingbased finite element (FE) models, which are typically built from CT/MR data obtained in supine position and employ pure rotation kinematics. We explored the sensitivity of FEbased lumbar passive rotational stiffness to two aspects of functional invivo kinematics: (a) passive strain changes from supine to upright standing position, and (b) invivo coupled translationrotation kinematics. We developed subjectspecific FE models of four subjects' L4L5 segments from supine CT images. Sagittally symmetric flexion was simulated in two ways: (i) pure flexion up to 12 degrees under a 500 N follower load directly from the supine pose. (ii) First, a displacementbased approach was implemented to attain the upright pose, as measured using Dynamic Stereo Xray (DSX) imaging. We then simulated invivo flexion using DSX imagingderived kinematics. Datasets from weightbearing motion with three different external weights [(4.5 kg), (9.1 kg), (13.6 kg)] were used. Accounting for supineupright motion generated compressive preloads approximate to 468 N (+/ 188 N) and a “pretorque” approximate to 2.5 Nm (+/ 2.2 Nm), corresponding to 25% of the reaction moment at 10 degrees flexion (case (i)). Rotational stiffness estimates from DSXbased coupled translationrotation kinematics were substantially higher compared to pure flexion. Reaction Moments were almost 90% and 60% higher at 5 degrees and 10 degrees of L4L5 flexion, respectively. Withinsubject differences in rotational stiffness based on external weight were small, although betweensubject variations were large. (C) 2020 Elsevier Ltd. All rights reserved.

Armaza, C., Hojman, S. A., Koch, B., & Zalaquett, N. (2016). On the possibility of nongeodesic motion of massless spinning tops. Class. Quantum Gravity, 33(14), 18 pp.
Abstract: The motion of spinning massless particles in gravitationally curved backgrounds is revisited by considering new types of constraints. Those constraints guarantee zero mass (P μP μ= 0) and they allow for the possibility of trajectories which are not simply null geodesics. To exemplify this previously unknown possibility, the equations of motion are solved for radial motion in Schwarzschild background. It is found that the particle experiences a spininduced energy shift, which is proportional to the Hawking temperature of the black hole background.

Chandia, O. (2011). The b ghost of the pure spinor formalism is nilpotent. Phys. Lett. B, 695(14), 312–316.
Abstract: The ghost for worldsheet reparametrization invariance is not a fundamental field in the pure spinor formalism. It is written as a combination of pure spinor variables which have conformal dimension two and such that it commutes with the BRST operator to give the worldsheet stress tensor. We show that the ghost variable defined in this way is nilpotent since the OPE of b with itself does not have singularities. (C) 2010 Elsevier B.V. All rights reserved.

Chandia, O., & Vallilo, B. C. (2016). Onshell type II supergravity from the ambitwistor pure spinor string. Class. Quantum Gravity, 33(18), 9 pp.
Abstract: We obtain all the type II supergravity constraints in the pure spinor ambitwistor string by imposing consistency of local worldsheet gauge symmetries.

Cisternas, J., Navarro, M., Duarte, S., & Concha, A. (2022). Equilibrium and symmetries of altitudinal magnetic rotors on a circle. Chaos, 32(12), 123120.
Abstract: Macroscopic magnets can easily be manipulated and positioned so that interactions between themselves and with external fields induce interesting dynamics and equilibrium configurations. In this work, we use rotating magnets positioned in a line or at the vertices of a regular polygon. The rotation planes of the magnets can be modified at will. The rich structure of stable and unstable configurations is dictated by symmetry and the side of the polygon. We show that both symmetric solutions and their symmetrybreaking bifurcations can be explained with group theory. Our results suggest that the predicted magnetic textures should emerge at any length scale as long as the interaction is polar, and the system is endowed with the same symmetries.

Cortez, V., Saravia, G., & Vogel, E. E. (2014). Phase diagram and reentrance for the 3D EdwardsAnderson model using information theory. J. Magn. Magn. Mater., 372, 173–180.
Abstract: Data compressor techniques are used to study the phase diagram of the generalized EdwardsAnderson model in three dimensions covering the full range of mixture between ferromagnetic (concentration 1x) and antiferromagnetic interactions (concentration x). The recently proposed data compressor wlzip is used to recognize criticality by the maximum information content in the files storing the simulation processes. The method allows not only the characterization of the ferromagnetic to paramagnetic (FP) transition (x < 0.22, or x > 0.78) but also it equally well yields the spinglass to paramagnetic (SP) transition (0.22 < x < 0.78). A reentrance of a ferromagnetic phase into the spinglass phase is found in the vicinity of the multicritical point. The differences in the ways to apply the new method to FP and SP transitions are reported. A phase diagram for the entire range of x based entirely on the use of compression techniques is obtained and discussed. The advantages and disadvantages of the method of data compression as compared to other methods to deal with magnetic phase transitions are brought out and explained. (C) 2014 Elsevier B.V. All rights reserved.

Hojman, S. A., & Asenjo, F. A. (2017). Spinning particles coupled to gravity and the validity of the universality of free fall. Class. Quantum Gravity, 34(11), 8 pp.
Abstract: Recent experimental work has determined that free falling Rb87 atoms on Earth, with vertically aligned spins, follow geodesics, thus apparently ruling out spingravitation interactions. It is showed that while some spinning matter models coupled to gravitation referenced to in that work seem to be ruled out by the experiment, those same experimental results confirm theoretical results derived from a Lagrangian description of spinning particles coupled to gravity constructed over forty years ago. A proposal to carry out (similar but) different experiments which will help to test the validity of the universality of free fall as opposed to the correctness of the aforementioned Lagrangian theory, is presented.

Mellado, P. (2020). Timescales in the thermal dynamics of magnetic dipolar clusters. Phys. Rev. B, 102(21), 214442.
Abstract: The collective behavior of thermally active structures offers clues on the emergent degrees of freedom and the physical mechanisms that determine the lowenergy state of a variety of systems. Here, the thermally active dynamics of magnetic dipoles at square plaquettes is modeled in terms of Brownian oscillators in contact with a heat bath. Solution of the Langevin equation for a set of interacting xy dipoles allows the identification of the timescales and correlation length that reveal how interactions, temperature, damping, and inertia may determine the frequency modes of edge and bulk magnetic mesospins in artificial dipolar systems.

Mellado, P. (2022). Intrinsic topological magnons in arrays of magnetic dipoles. Sci. Rep., 12(1), 1420.
Abstract: We study a simple magnetic system composed of periodically modulated magnetic dipoles with an easy axis. Upon adjusting the geometric modulation amplitude alone, chains and twodimensional stacked chains exhibit a rich magnon spectrum where frequency gaps and magnon speeds are easily manipulable. The blend of anisotropy due to dipolar interactions between magnets and geometrical modulation induces a magnetic phase with fractional Zak number in infinite chains and end states in open onedimensional systems. In two dimensions it gives rise to topological modes at the edges of stripes. Tuning the amplitude in twodimensional lattices causes a band touching, which triggers the exchange of the Chern numbers of the volume bands and switches the sign of the thermal conductivity.

Pandiyarajan, T., Mangalaraja, R. V., Karthikeyan, B., Arulraj, A., & GraciaPinilla, M. A. (2023). Fabrication and spectroscopic investigation of sandwichlike ZnO:rGO:ZnO: rGO:ZnO structure by layerbylayer approach. Inorg. Chem. Commun., 149, 110383.
Abstract: Transparent conducting materials (TCMs) are the heart of modern optoelectronic industries and the properties of TCMs could be improved by the introduction of 2D carbon materials. In this report, the influence of order layering on microstructural, transparency and emission characteristics of ZnO:rGO:ZnO:rGO:ZnO and rGO:ZnO: rGO:ZnO:rGO sandwich structures has been investigated. The layerbylayer approach has been adopted for the fabrication of sandwich structured materials ZnO:rGO:ZnO:rGO:ZnO and rGO:ZnO:rGO:ZnO:rGO through the spin coating technique. The sandwich structures of ZnO and rGO exhibited hexagonal wurtzite structure of ZnO without any impurities were identified through XRD. The ordering of layer's influenced the microstructural parameters and were significantly altered. The spherical nature of the particles and the formation of the sandwich structures were confirmed by using SEM micrograph. The reduction in an optical transparency and narrowing bandgap of the ZnO upon the order of layering were identified through transmission spectra. The lower energy shift of near band edge (NBE) emission and reduction in the emission intensity with respect to pure ZnO nanostructures was observed. The present work provides a simple layerbylayer approach to fabricating sandwich structures and improving the optical properties which have potential applications in various optoelectronic devices.

Rice, M., Wang, X. Y., Wang, S. H., Shporer, A., Barkaoui, K., Brahm, R., et al. (2023). Evidence for Lowlevel Dynamical Excitation in Nearresonant Exoplanet Systems. Astron. J., 166(6), 266.
Abstract: The geometries of nearresonant planetary systems offer a relatively pristine window into the initial conditions of exoplanet systems. Given that nearresonant systems have likely experienced minimal dynamical disruptions, the spinorbit orientations of these systems inform the typical outcomes of quiescent planet formation, as well as the primordial stellar obliquity distribution. However, few measurements have been made to constrain the spinorbit orientations of nearresonant systems. We present a RossiterMcLaughlin measurement of the nearresonant warm Jupiter TOI2202 b, obtained using the Carnegie Planet Finder Spectrograph on the 6.5 m Magellan Clay Telescope. This is the eighth result from the Stellar Obliquities in Longperiod Exoplanet Systems survey. We derive a skyprojected 2D spinorbit angle lambda = 26(15)(+12 degrees) and a 3D spinorbit angle Psi = 31(11)(+13 degrees), finding that TOI2202 bthe most massive nearresonant exoplanet with a 3D spinorbit constraint to datelikely deviates from exact alignment with the host star's equator. Incorporating the full census of spinorbit measurements for nearresonant systems, we demonstrate that the current set of nearresonant systems with period ratios P2/P1 less than or similar to 4 is generally consistent with a quiescent formation pathway, with some room for lowlevel (less than or similar to 20 degrees) protoplanetary disk misalignments or postdiskdispersal spinorbit excitation. Our result constitutes the first populationwide analysis of spinorbit geometries for nearresonant planetary systems.

Zalaquett, N., Hojman, S. A., & Asenjo, F. A. (2014). Spinning massive test particles in cosmological and general static spherically symmetric spacetimes. Class. Quantum Gravity, 31(8), 21 pp.
Abstract: A Lagrangian formalism is used to study the motion of a spinning massive particle in FriedmannRobertsonWalker and Godel spacetimes, as well as in a general Schwarzschildlike spacetime and in static spherically symmetric conformally flat spacetimes. Exact solutions for the motion of the particle and general exact expressions for the momenta and velocities are displayed for different cases. In particular, the solution for the motion in spherically symmetric metrics is presented in the equatorial plane. The exact solutions are found using constants of motion of the particle, namely its mass, its spin, its angular momentum, and a fourth constant, which is its energy when the metric is timeindependent, and a different constant otherwise. These constants are associated to Killing vectors. In the case of the motion on the FriedmannRobertsonWalker metric, a new constant of motion is found. This is the fourth constant which generalizes previously known results obtained for spinless particles. In the case of general Schwarzschildlike spacetimes, our results allow for the exploration of the case of the ReissnerNordstrom(Anti) de Sitter metric. Finally, for the case of the conformally flat spacetimes, the solution is explicitly evaluated for different metric tensors associated to a universe filled with static perfect fluids and electromagnetic radiation. For some combination of the values of the constants of motion the particle trajectories may exhibit spacelike velocity vectors in portions of the trajectories.
