Possible signatures of mixed-parity superconductivity in doped polar SrTiO3 films

Superconductors that possess both broken spatial inversion symmetry and spin-orbit interactions exhibit a mix of spin singlet and triplet pairing. Here, we report on measurements of the superconducting properties of electron-doped, strained SrTiO3 films. These films have an enhanced superconducting transition temperature and were previously shown to undergo a transition to a polar phase prior to becoming superconducting. We show that some films show signatures of an unusual superconducting state, such as an in-plane critical field that is higher than both the paramagnetic and orbital pair breaking limits. Moreover, nonreciprocal transport, which reflects the ratio of odd versus even pairing interactions, is observed. Together, these characteristics indicate that these films provide a tunable platform for investigations of unconventional superconductivity

Assessment and tuning of the behaviour of a microphysical characterisation scheme

International audienceThe correct classification of prevailing bulk hydrometeor type within a radar resolution volume is a challenge task even if a full set of polarimetric radar observables is available. Indeed scattering and propagation effects from the variety of hydrometeors present interact each others and sometimes, if not often, tend to obscure the characteristic signature of each weather radar target type. This consideration is enforced when the atmospheric volume is sampled with a wavelength where both Mie scattering effects and attenuation start to become relevant. In this paper, we utilize the hydrometeor classification scheme developed at the National Severe Storms Laboratory (USA). Briefly, the scheme uses a fuzzy logic approach to combine different polarimetric variables and environmental temperature in order to determine the most likely type of prevalent hydrometeor in the radar volume. This means that the resulting classification is based on two characteristics: the volume polarimetric responses and the thermal value. The relative balance between these two is managed through the coefficients in the fuzzy scheme. We have observed that these parameters are crucial in order to get "physical reasonable result", independently from the meteorological character of the event investigated. Our work is based on a reduced set of polarimetric variables (Z and ZDR) as input. Data used in this study were collected by a C-band radar over weather events ranging from convective to stratiform

A non-linear observer for unsteady three-dimensional flows

A method is proposed to estimate the velocity field of an unsteady flow using a limited number of flow measurements. The method is based on a non-linear low-dimensional model of the flow and on expanding the velocity field in terms of empirical basis functions. The main idea is to impose that the coefficients of the modal expansion of the velocity field give the best approximation to the available measurements and that at the same time they satisfy as close as possible the non-linear low-order model. The practical use may range from feedback flow control to monitoring of the flow in non-accessible regions. The proposed technique is applied to the flow around a confined square cylinder, both in two- and three-dimensional laminar flow regimes. Comparisons are provided. with existing linear and non-linear estimation techniques

Application of the Cloude-Pottier decomposition to weather radar signatures

In this paper we apply the Cloude-Pottier decomposition to Weather Radar Signatures. First, we present the results of a simulation carried out at the Chemnitz University of Technology and give the expected H-α values for different rain intensities. A comparison with standard radarmeteorological variables is also given. Then, first ever images of Entropy and Anisotropy are presented for clouds and precipitation. Experimental Data are from the POLDIRAD Weather Facility in Oberpfaffenhofen, Germany

Structural connectivity and functional properties of the macaque superior parietal lobule

Despite the consolidated belief that the macaque superior parietal lobule (SPL) is entirely occupied by Brodmann’s area 5, recent data show that macaque SPL also hosts a large cortical region with structural and functional features similar to that of Brodmann’s area 7. According to these data, the anterior part of SPL is occupied by a somatosensory-dominated cortical region that hosts three architectural and functional distinct regions (PE, PEci, PEip) and the caudal half of SPL by a bimodal somato-visual region that hosts four areas: PEc, MIP, PGm, V6A. To date, the most studied areas of SPL are PE, PEc, and V6A. PE is essentially a high-order somatomotor area, while PEc and V6A are bimodal somatomotor–visuomotor areas, the former with predominant somatosensory input and the latter with predominant visual input. The functional properties of these areas and their anatomical connectivity strongly suggest their involvement in the control of limb movements. PE is suggested to be involved in the preparation/execution of limb movements, in particular, the movements of the upper limb; PEc in the control of movements of both upper and lower limbs, as well as in their interaction with the visual environment; V6A in the control of reach-to-grasp movements performed with the upper limb. In humans, SPL is traditionally considered to have a different organization with respect to macaques. Here, we review several lines of evidence suggesting that this is not the case, showing a similar structure for human and non-human primate SPLs

Mixing sensitivity to the inclination of the lateral walls in a T-mixer

One of the simplest geometries for micro-mixers has a T-shape, i.e., the two inlets join perpendicularly the mixing channel. The cross-sections of the channels are usually square/rectangular, as straight walls facilitate experimental and modeling analysis. On the contrary, this work investigates through Computational Fluid Dynamics the effect of a cross-section with lateral walls inclined of an angle α as such an inclination may stem from different microfabrication techniques. Considering water as operating fluid, the same mixing performance as square/rectangular cross-sections is obtained for inclinations α≤3°; this indicates the maximum admissible error on the perpendicularity of the walls in the manufacturing process. Above this value, the presence of inclined walls delays the onset of the engulfment regime at higher Reynolds numbers, and for α≥23°the mixing is hampered dramatically, as the flow is unable to break the mirror symmetry and enter in the engulfment regime. At low Reynolds numbers, the mixing is moderately improved for α≥10°, because the vortex regime presents a lower degree of symmetry than that of T-mixers with straight walls

Unsteady flow regimes in arrow-shaped micro-mixers with different tilting angles

Two arrow-shaped micro-mixers, obtained from the classical T-shaped geometry by tilting downward the inlet channels, are considered herein. The two configurations, having different tilting angle values, have been chosen since they show significantly different flow topologies and mixing performances at low Reynolds numbers. In the present paper, we use both experimental flow visualizations and direct numerical simulations to shed light on the mixing behavior of the two configurations for larger Reynolds numbers, for which the mixers present unsteady periodic flows, although in laminar flow conditions. The tilting angle influences the flow dynamics also in the unsteady regimes and has a significant impact on mixing. The configuration characterized by the lower tilting angle, i.e., α = 10°, ensures a better global mixing performance than the one with the larger angle, i.e., α = 20°

Covert Shift of Attention Modulates the Ongoing Neural Activity in a Reaching Area of the Macaque Dorsomedial Visual Stream

Background: Attention is used to enhance neural processing of selected parts of a visual scene. It increases neural responses to stimuli near target locations and is usually coupled to eye movements. Covert attention shifts, however, decouple the attentional focus from gaze, allowing to direct the attention to a peripheral location without moving the eyes. We tested whether covert attention shifts modulate ongoing neuronal activity in cortical area V6A, an area that provides a bridge between visual signals and arm-motor control. Methodology/Principal Findings: We performed single cell recordings from 3 Macaca Fascicularis trained to fixate straight-head, while shifting attention outward to a peripheral cue and inward again to the fixation point. We found that neurons in V6A are influenced by spatial attention. The attentional modulation occurs without gaze shifts and cannot be explained by visual stimulations. Visual, motor, and attentional responses can occur in combination in single neurons. Conclusions/Significance: This modulation in an area primarily involved in visuo-motor transformation for reaching may form a neural basis for coupling attention to the preparation of reaching movements. Our results show that cortical processes of attention are related not only to eye-movements, as many studies have shown, but also to arm movements, a finding that has been suggested by some previous behavioral findings. Therefore, the widely-held view that spatial attention is tightly intertwined with - and perhaps directly derived from - motor preparatory processes should be extended to a broader spectrum of motor processes than just eye movements

Influence of Topological Edge States on the Properties of Al/Bi2Se3/Al Hybrid Josephson Devices

In superconductor-topological insulator-superconductor hybrid junctions, the barrier edge states are expected to be protected against backscattering, to generate unconventional proximity effects, and, possibly, to signal the presence of Majorana fermions. The standards of proximity modes for these types of structures have to be settled for a neat identification of possible new entities. Through a systematic and complete set of measurements of the Josephson properties we find evidence of ballistic transport in coplanar Al-Bi2Se3-Al junctions that we attribute to a coherent transport through the topological edge state. The shunting effect of the bulk only influences the normal transport. This behavior, which can be considered to some extent universal, is fairly independent of the specific features of superconducting electrodes. A comparative study of Shubnikov - de Haas oscillations and Scanning Tunneling Spectroscopy gave an experimental signature compatible with a two dimensional electron transport channel with a Dirac dispersion relation. A reduction of the size of the Bi2Se3 flakes to the nanoscale is an unavoidable step to drive Josephson junctions in the proper regime to detect possible distinctive features of Majorana fermions.Comment: 11 pages, 14 figure

Bio-additives for CI engines from one-pot alcoholysis reaction of lignocellulosic biomass: An experimental activity

In the recent years the progressive decrease in fossil petroleum resources and gradual deprivation of the environment have attracted increasing interest towards the use of biomass as renewable carbon source for the production of chemicals and transportation fuels. In particular, lignocellulosic biomass represents an abundant and inexpensive renewable resource with high carbon sequestration ability and non-polluting. In this paper, the valorisation of mixtures made of n-butanol (n-BuOH), butyl levulinate (BL) and dibutyl ether (DBE), in different percentages, as additive fuel for compression ignition (CI) internal combustion engine (ICE) was studied. These mixtures can be directly obtained from the catalytic alcoholysis reaction of the cellulosic fraction of raw and pre-treated lignocellulosic biomasses. Moreover, the possibility to recycle and reutilize the excess alcohol (n-Butanol), during the catalytic alcoholysis reaction, has been considered since it represents an opportunity to reduce the overall costs of the process. Therefore, a blend constituted only by BL and DBE has been also tested. The model mixtures were prepared by using commercial reactants, characterized by compositions analogous to those of the reaction mixtures. These model mixtures were tested as blend with Diesel fuel in a CI-ICE with the measurement of pollutant emission and performance. Results have been compared with those obtained fuelling the engine with a commercial Diesel fuel. As a whole, tests results have evidenced the potentiality of these novel blending mixtures to reduce the emissions of particulate without any significant increase in the other pollutants and negligible changes in engine power and efficiency