Comprehensive Optimization of the Tripolar Concentric Ring Electrode with Respect to the Accuracy of Laplacian Estimation Based on the Finite Dimensions Model of the Electrode

Optimization performed in this study is based on the finite dimensions model of the concentric ring electrode as opposed to the negligible dimensions model widely used in the past. This makes the optimization problem comprehensive since all of the electrode parameters, including, for the first time, the radius of the central disc and individual widths of concentric rings, are optimized simultaneously. The optimization criterion used is maximizing the accuracy of the surface Laplacian estimation since the ability to estimate the Laplacian at each electrode constitutes the primary biomedical significance of concentric ring electrodes. Even though the obtained results and derived principles defining optimal electrode configurations are illustrated on tripolar (two concentric rings) electrodes, they were also confirmed for quadripolar (three rings) and pentapolar (four rings) electrodes and are likely to continue to hold for any higher number of concentric rings. For tripolar concentric ring electrodes, the optimal configuration was compared to previously proposed, linearly increasing inter-ring distances and constant inter-ring distances in configurations of the same size and based on the same finite dimensions model of the electrode. The obtained results suggest that previously proposed configurations correspond to almost two-fold and more than three-fold increases in Laplacian estimation error, respectively, compared to the optimal configuration proposed in this study.

DETERMINATION OF IMMERSION RESISTANCE OF THE CENTRAL DISC OF SEEDING SECTION AND ITS TECHNICAL SOLUTION

Nowadays, the methods of performing research in agricultural engineering, as well as the used equipment, have stepped forward. Many instruments for determining pressure, torque, travel speed, rotational speed, and so on, are based on the use of electrical impulses, magnetic fields and other fundamentals. As a rule, such devices are quite expensive and not always available. Therefore, in the field, researchers use strain gauge equipment, make strain gauge blocks, and calibrate them. Our task is to determine the resistance force of a flat disc sinking into the soil when the unit moves. Therefore, it was decided to develop and calibrate the installation for determining the immersion resistance force of the central disc of the seeding section. The article presents a diagram of a device for determining the immersion resistance force of the central disc of the seeding section, which made it possible to obtain experimental data and to find the dependence of the resistance force of a flat disc when deepening into the soil.

xGASS: passive discs do not host unexpectedly large reservoirs of cold atomic hydrogen

ABSTRACT We use the extended GALEX Arecibo SDSS Survey (xGASS) to quantify the relationship between atomic hydrogen (H i) reservoir and current star formation rate (SFR) for central disc galaxies. This is primarily motivated by recent claims for the existence, in this sample, of a large population of passive discs harbouring H i reservoirs as large as those observed in main-sequence galaxies. Across the stellar mass range 109 < M*/M⊙ < 1011, we practically find no passive (≳2σ below the star forming main sequence) disc galaxies with H i reservoirs comparable to those typical of star-forming systems. Even including H i non-detections at their upper limits, passive discs typically have ≥0.5 dex less H i than their active counterparts. We show that previous claims are due to the use of aperture-corrected SFR estimates from the MPA/JHU SDSS DR7 catalogue, which do not provide a fair representation of the global SFR of H i-rich galaxies with extended star-forming discs. Our findings confirm that the bulk of the passive disc population in the local Universe is H i-poor. These also imply that the reduction of star formation, even in central disc galaxies, has to be accompanied by a reduction in their H i reservoir.

Validating the Comparison Framework for the Finite Dimensions Model of Concentric Ring Electrodes Using Human Electrocardiogram Data

While progress has been made in design optimization of concentric ring electrodes maximizing the accuracy of the surface Laplacian estimation, it was based exclusively on the negligible dimensions model of the electrode. Recent proof of concept of the new finite dimensions model that adds the radius of the central disc and the widths of concentric rings to the previously included number of rings and inter-ring distances provides an opportunity for more comprehensive design optimization. In this study, the aforementioned proof of concept was developed into a framework allowing direct comparison of any two concentric ring electrodes of the same size and with the same number of rings. The proposed framework is illustrated on constant and linearly increasing inter-ring distances tripolar concentric ring electrode configurations and validated on electrocardiograms from 20 human volunteers. In particular, ratios of truncation term coefficients between the two electrode configurations were used to demonstrate the similarity between the negligible and the finite dimension models analytically (p = 0.077). Laplacian estimates based on the two models were calculated on electrocardiogram data for emulation of linearly increasing inter-ring distances tripolar concentric ring electrode. The difference between the estimates was not statistically significant (p >> 0.05) which is consistent with the analytic result.

Evaluation of the triangular fibrocartilage: comparison of two-compartment wrist CT arthrography using the distal radioulnar and radiocarpal joints and unicompartment wrist CT arthrography using the radiocarpal joint

Objective: To compare the diagnostic performance of two-compartment wrist CT arthrography of the distal radioulnar and radiocarpal joints and unicompartment wrist CT arthrography of the radiocarpal joint in depiction of the triangular fibrocartilage tear. Methods: From January 2016 to December 2017, two-compartment CT arthrography of 74 consecutive patients (36 females, 38 males; mean age, 37.2 years) and unicompartment CT arthrography of 51 consecutive patients (18 females, 33 males; mean age, 40.1 years) were obtained. All CT arthrography images were independently and blindly evaluated by two radiologists for the presence of the triangular fibrocartilage tear by grade (partial or full thickness) per its locations: central disc proper, central-peripheral junction, proximal and distal laminae of its ulnar attachment. Fisher’s exact test was used for a statistical analysis, and a p-value less than 0.05 was considered as significant. The arthroscopic findings of 47 patients (34 patients with two-compartment CT arthrography and 13 patients with unicompartment CT arthrography) were evaluated for calculating sensitivity, specificity, and accuracy. Results: All partial and full thickness triangular fibrocartilage tears were identified more commonly by their location except for distal laminae on two-compartment CT arthrography than were unicompartment CT arthrography (p = 0.001–0.022). Two-compartment CT arthrography had high sensitivity (90.9–100%) and low specificity (33.3–76.5%) for detecting central disc proper and proximal lamina tears, comparing with unicompartment CT arthrography. Conclusion: Two-compartment wrist CT arthrography is more helpful for detecting triangular fibrocartilage tears than unicompartment wrist CT arthrography. Advances in knowledge: It could be important to evaluate the ulnar foveal insertion of the TFCC in clinical practice, which plays the most important role in DRUJ instability and ulnar-sided wrist pain. Two-compartment wrist CTA of the DRUJ and RCJ could improve diagnostic sensitivity in the TFC tear in terms of its location and torn degree over that of unicompartment wrist CTA of the RCJ. Two-compartment wrist CTA of the DRUJ and RCJ may be recommended as a diagnostic imaging, rather than unicompartment wrist CTA of the RCJ, when peripheral foveal tear of TFC is suspected, especially in young patients.

A new species of Conocybe (Bolbitaceae) from Punjab, Pakistan

Conocybe punjabensis sp. nov., a species belonging to the saprobic family Bolbitaceae, is illustrated and described from Pakistan based on morphology and molecular evidence. The species can be distinguished on the basis of medium-sized fruiting bodies, a pileus with a dark brown central disc, a fibrillose stipe, forked lamellae near pileus margin, ellipsoid angular basidiospores with an apical germ pore, cheilocystidia and pleurocystidia varying from catenulate, lecythiform to clavate, and lecythiform caulocystidia. Molecular phylogenetic analysis of the nuclear ribosomal ITS region also supports the recognition of this new species in Conocybe. Detailed descriptions, photographs, illustrations and comparison with allied taxa are given.

Strain-controlled Graphene-Polymer Angular Actuator

ABSTRACTWe demonstrate a suspended graphene-(poly(methyl methacrylate) (PMMA) polymer angular displacement actuator enabled by variable elastic modulus of the perforated stacked structure. Azimuthal flexures support a central disc-shaped membrane, and compression of the membrane can be used to control the rotation of the entire structure. Irradiating the PMMA on graphene stack with 5 kV electrons in a convention scanning electron microscope reduces the elastic modulus of the PMMA and allows graphene’s built in strain to dominate and compress the flexures, thus rotating the actuator.

Setitheca lativalva gen. et sp. nov., a fossil flower of Laurales from mid-Cretaceous Myanmar amber

A single staminate flower preserved in mid-Cretaceous Myanmar amber is described as Setitheca lativalva gen. et sp. nov. The fossil’s affinities appear to be with Monimiaceae and allied families of order Laurales. The perianth is composed of ca. 12 spirally arranged tepals of varying size and shape. A single whorl of 10 stamens is attached to the margin of a flat central disc. There is no gynoecium. In some of the stamens, the bilocular anthers are held upright, but in the others, the filaments are arched abaxially and the anthers are reflexed. Dehiscence is extrorse via 2 lateral, dorsally-hinged valves, as also occurs in some members of Hernandiaceae. The spherical pollen appears to be inaperturate. Such features as the unisexual flowers, valvate anthers, and a perianth of numerous, spirally arranged tepals are consistent with assignment of the fossil to this order of angiosperms.