Orbital symmetry fingerprints for magnetic adatoms in graphene

In this paper, we describe the formation of local resonances in graphene in the presence of magnetic adatoms containing localized orbitals of arbitrary symmetry, corresponding to any given angular momentum state. We show that quantum interference effects which are naturally inbuilt in the honeycomb lattice in combination with the specific orbital symmetry of the localized state lead to the formation of fingerprints in differential conductance curves. In the presence of Jahn-Teller distortion effects, which lift the orbital degeneracy of the adatoms, the orbital symmetries can lead to distinctive signatures in the local density of states. We show that those effects allow scanning tunneling probes to characterize adatoms and defects in graphene.Comment: 15 pages, 11 figures. Added discussion about the multi-orbital case and the validity of the single orbital picture. Published versio

Estabilidade durante armazenamento de hambúrguer vegetal elaborado à base de caju.

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Natural Disasters and Financial Technology Adoption

This paper investigates the adoption of financial technology, with a specific focus on the introduction of a new instant payment technology called PIX by the Brazilian Central Bank. To assess adoption patterns, we use Brazilian data and leverage the occurrence of natural disasters in Brazilian municipalities as an exogenous variation. Our empirical findings indicate that adopting the new payment technology increases after a natural disaster, with increases in transaction volume ranging from 6.4% to 8.9% after eight months. Furthermore, we document that changes in other banking transactions do not drive these findings. We also conduct a series of analyses to confirm the robustness of our results in the context of the COVID-19 pandemic, the seasonality of tourist cities, and the number of bank branches

Noninvasive measurement of sciatic nerve stiffness in patients with chronic low back related leg pain using shear wave elastography

Objectives—The purpose of this study was to determine whether sciatic nerve stiffness is altered in people with chronic low back–related leg pain by using shear wave elastography. Methods—In this cross-sectional study, the sciatic nerve shear wave velocity (ie, an index of stiffness) was measured in both legs of 16 participants (8 with unilateral low back–related leg pain and 8 healthy controls). Sciatic stiffness was measured during a passive ankle dorsiflexion motion performed at 28/s in an isokinetic dynamometer. The ankle range of motion and passive torque, as well as muscle activity, were also measured. Results—In people with low back–related leg pain, the affected limb showed higher sciatic nerve stiffness compared to the unaffected limb (111.3%; P5.05). However, no differences were observed between the unaffected limb of people with low back–related leg pain and the healthy controls (P5.34). Conclusions—People with chronic low back–related leg pain have interlimb differences in sciatic nerve stiffness, as measured by a safe and noninvasive method: shear wave elastography. The changes found may be related to alterations in nerve mechanical properties, which should be confirmed by future investigations.info:eu-repo/semantics/publishedVersio

Theory of Scanning Tunneling Spectroscopy of Magnetic Adatoms in Graphene

We examine theoretically the signatures of magnetic adatoms in graphene probed by scanning tunneling spectroscopy (STS). When the adatom hybridizes equally with the two graphene sublattices, the broadening of the local adatom level is anomalous and can scale with the cube of the energy. In contrast to ordinary metal surfaces, the adatom local moment can be suppressed by the proximity of the probing scanning tip. We propose that the dependence of the tunneling conductance on the distance between the tip and the adatom can provide a clear signature for the presence of local magnetic moments. We also show that tunneling conductance can distinguish whether the adatom is located on top of a carbon atom or in the center of a honeycomb hexagon.Comment: 4.1 pages, 4 figure

Hamstring stiffness pattern during contraction in healthy individuals: analysis by ultrasound-based shear wave elastography

Purpose To assess the stiffness of hamstring muscles during isometric contractions in healthy individuals, using ultrasoundbased shear wave elastography to (1) determine the intra- and inter-day assessment repeatability, (2) characterize the stiffness of semitendinosus (ST) and biceps femoris long head (BFlh) along the contraction intensity, and (3) characterize stiffness distribution among the hamstring muscles and inter-limb symmetry. Methods Two experiments were conducted. In experiment I (n = 12), the intra-day repeatability in assessing the BFlh and ST stiffness were determined at intensities between 10–60% of maximal voluntary isometric contraction (MVIC) in a single session. In experiment II (n = 11), the stiffness of the hamstring muscles of both thighs was assessed at 20% of MVIC in the first session; and retested (for one randomly chosen thigh) in a second session. Isometric contraction of knee flexors was performed with the knee flexed at 30° and with the hip in a neutral position. Results Moderate-to-very-high intra- and inter-day repeatability was found (ICC = 0.69–0.93). The BFlh/ST stiffness ratio increased with contraction intensity. At 20% of MVIC, the ST showed the highest stiffness among the hamstring muscles (p 0.474). No differences were found between limbs (p = 0.12). Conclusions The stiffness distribution among the hamstring muscles during submaximal isometric contractions is heterogeneous, but symmetric between limbs, and changes depending on the contraction intensity. Shear wave elastography is a reliable tool to assess the stiffness of hamstring muscles during contraction.info:eu-repo/semantics/publishedVersio

Diffusivities of linear unsaturated ketones and aldehydes in compressed liquid ethanol

For the accurate design, optimization and simulation of chemical processes limited by mass transfer kinetics it is important the knowledge of transport properties, namely, diffusion coefficients, D12. In this work, the D12 values of six unsaturated linear ketones (i.e., propanone, butanone, propan-2-one, propan-3-one, hexan-2-one and hexan-3-one) and three unsaturated linear aldehydes (i.e., butanal, pentanal and hexanal) in (compressed) liquid ethanol were measured at temperatures from 303.15 K to 333.15 K and pressures up to 150 bar. The D12 values of ketones are in the range of 1.28 × 10−5 – 2.89 × 10−5 cm2 s−1 and of the aldehydes are between 1.39 × 10−5 and 2.68 × 10−5 cm2 s−1. The general trends of D12 regarding temperature, pressure, Stokes-Einstein coordinate, and free volume are presented and discussed. The diffusivities of the various ketones position isomers and aldehyde/ketone isomers were statistically compared, being possible to conclude that the former ones exhibit indistinguishable diffusivities while different values appear for aldehydes/ketones isomers. Finally, five models and a machine learning algorithm from the literature were tested to predict/correlate the new data. It is suggested that the TLSM model should be the preferred approach for D12 prediction of linear unsaturated aldehydes and ketones in liquid compressed ethanol.publishe

Magnetic control of Weyl nodes and wave packets in three-dimensional warped semimetals

We investigate the topological phase transitions driven by band warping and a transverse magnetic field, for three-dimensional Weyl semimetals. First, we use the Chern number as a mathematical tool to derive the topological phase diagram. Next, we associate each of the topological sectors to a given angular momentum state of a rotating wave packet. Then we show how the position of the Weyl nodes can be manipulated by a transverse external magnetic field that ultimately quenches the wave packet rotation, first partially and then completely, thus resulting in a sequence of field-induced topological phase transitions. Finally, we calculate the current-induced magnetization and the anomalous Hall conductivity of a prototypical warped Weyl material. Both observables reflect the topological transitions associated with the wave packet rotation and can help to identify the elusive 3D quantum anomalous Hall effect in three-dimensional, warped Weyl materials.Comment: 6 pages, 5 figure

Some interesting features of new massive gravity

A proof that new massive gravity - the massive 3D gravity model proposed by Bergshoeff, Hohm and Townsend (BHT) - is the only unitary system at the tree level that can be constructed by augmenting planar gravity through the curvature-squared terms, is presented. Two interesting gravitational properties of the BHT model, namely, time dilation and time delay, which have no counterpart in the usual Einstein 3D gravity, are analyzed as well.Comment: Submitted to Classical and Quantum Gravit