Magnetic and orbital order in overdoped bilayer manganites

The magnetic and orbital orders for the bilayer manganites in the doping region $0.5 < x <1.0$ have been investigated from a model that incorporates the two $e_g$ orbitals at each Mn site, the inter-orbital Coulomb interaction and lattice distortions. The usual double exchange operates via the $e_g$ orbitals. It is shown that such a model reproduces much of the phase diagram recently obtained for the bilayer systems in this range of doping. The C-type phase with ($\pi,0,\pi$) spin order seen by Ling et al. appears as a natural consequence of the layered geometry and is stabilised by the static distortions of the system. The orbital order is shown to drive the magnetic order while the anisotropic hopping across the $e_g$ orbitals, layered nature of the underlying structure and associated static distortions largely determine the orbital arrangements.Comment: 8 pages, 5 figure

Quantitative Microbial Risk Assessment Using Azred Water Quality Models

Cryptosporidiosis is a common gastrointestinal disease that significantly impacts immune-compromised individuals. In this study, water quality analysis and doseresponse models are used to calculate the location-based risk of Cryptosporidium infection within 24 hours of an intrusion into a drinking water system. Current water quality models such as EP ANET are based upon two main assumptions: complete mixing occurs at pipe cross junctions, and axial dispersion of a solute does not occur along the length of a pipe. To improve the accuracy of EPANET, two newly developed models, AZRED I and II, consider these assumptions. EP ANET-generated simulations model plug flow-the movement of large contaminant concentration pulses with respect to time-while AZRED-generated simulations model solute dispersion, which results in lower contaminant concentrations over a longer period of time. The risk of infection was calculated for populations at four specific locations in a network using an exponential model. Results obtained using AZRED, when compared to results obtained from EPANET, predicted a higher risk of infection at downstream locations.Digitized from a paper copy provided by the Physiological Sciences Graduate Interdisciplinary Program

Task specificity and neural adaptations after balance learning in young adults

Background: Only 30 min of balance skill training can significantly improve behavioral and neuromuscular outcomes. However, it is unclear if such a rapidly acquired skill is also retained and transferred to other untrained balance tasks.Research question: What are the effects of a single balance training session on balance skill acquisition, retention, and transferability and on measures of neural plasticity examined by transcranial magnetic brain stimulation (TMS) and inter-muscular coherence?Methods: Healthy younger adults (n = 36, age 20.9, 18 M) were randomly assigned to: Balance training (BT); Active control (cycling training, CT) or non-active control (NC) and received a 20min intervention. Before, immediately and similar to 7 days after the interventions, we assessed performance in the trained wobble board task, untrained static standing tasks and dynamic beam walking balance tasks. Underlying neural plasticity was assessed by tibialis anterior motor evoked potential, intracortical facilitation, short-interval intracortical inhibition and long-interval intracortical inhibition using TMS and by inter-muscular coherence.Results: BT, but not CT (18%, d = 0.32) or NC (-1%, d = -0.02), improved balance performance in the trained, wobble board task by 207% (effect size d = 2.12). BT retained the acquired skill after a 1-week no-training period (136%, d = 1.57). No changes occurred in 4 measures of balance beam walking, in 8 measures of static balance, in 8 measures of intermuscular coherence, and in 4 TMS measures of supra-spinal plasticity (all p &gt; 0.05).Significance: Healthy young adults can learn a specific balance skill very rapidly but one should be aware that while such improvements were retained, the magnitude of transfer (32%, d = 0.94) to other balancing skills was statistically not significant. Additional studies are needed to determine the underlying neural mechanisms of rapid balance skill acquisition, retention, and transfer.</p

Effect of hydrostatic pressure and alloying on thermoelectric properties of van der Waals solid KMgSb: An \textit{ab-initio} study

Through a combined first-principles and Boltzmann transport theory, we systematically investigate the thermal and electrical transport properties of the unexplored ternary quasi two-dimensional KMgSb system of KMgX (X = P, As, Sb, and Bi) family. Herein, the transport properties of KMgSb under the application of hydrostatic pressure and alloy engineering are reported. At a carrier concentration of $\sim8\times10^{19}~\mathrm{cm^{-3}}$, the figure of merit zT ($\sim0.75$) for both the $n$-type and $p$-type of KMgSb closely matched, making it an attractive option for engineering both legs of a thermoelectric device using the same material. This is particularly desirable for high-performance thermoelectric applications. Furthermore, the zT value increases as pressure decreases, further enhancing its potential for use in thermoelectric devices. In the case of substitutional doping (replacing 50 \% Sb by Bi atom), we observed $\sim49~\%$ (in-plane) increase in the peak thermoelectric figure of merit (zT). The maximum zT value obtained after alloy engineering is $\sim1.45$ at 900~K temperature. Hydrostatic pressure is observed to be a great tool to tune the lattice thermal conductivity ($\kappa_L$). We observed that the negative pressure-like effects could be achieved by chemically doping bigger-size atoms, especially when $\kappa_L$ is a property under investigation. Through our computational investigation, we explain that hydrostatic pressure and alloy engineering may improve thermoelectric performance dramatically.Comment: 10 pages, 8 figures, and Supplementary Informatio

Spin and current transport in the robust half-metallic magnet cc-CoFeGe

Spintronics is an emerging form of electronics based on the electrons' spin degree of freedom for which materials with robust half-metallic ferromagnet (HMF) character are very attractive. Here we determine the structural stability, electronic, magnetic, and mechanical properties of the half-Heusler (hH) compound CoFeGe, in particular also in its cubic form. The first-principles calculations suggest that the electronic structure is robust with 100 \% spin polarization at the Fermi level under hydrostatic pressure and uni-axial strain. Both the longitudinal and Hall current polarization are calculated and the longitudinal current polarization ($P_{L}$) is found to be $>99\%$ and extremely robust under uniform pressure and uni-axial strain. The anomalous Hall conductivity (AHC) and Spin Hall conductivity (SHC) of hH cubic CoFeGe (\textit{c}-CoFeGe) are found to be $\sim -100$ S/cm and $\sim 39~\hbar/e$ S/cm, respectively. Moreover, the Curie temperature of the alloy is calculated to be $\sim$524 K with a 3 $\mu_{B}$ magnetic moment. Lastly, the calculated mechanical properties indicate that \textit{c}-CoFeGe is ductile and mechanically stable with a bulk modulus of $\approx$ 154 GPa. Overall, this analysis reveals that cubic CoFeGe is a robust half-metallic ferromagnet and an interesting material for spintronic applications.Comment: 8 pages, 6 figures, and 2 table

tDCS induced GABA change is associated with the simulated electric field in M1, an effect mediated by grey matter volume in the MRS voxel

Background and objective Transcranial direct current stimulation (tDCS) has wide ranging applications in neuro-behavioural and physiological research, and in neurological rehabilitation. However, it is currently limited by substantial inter-subject variability in responses, which may be explained, at least in part, by anatomical differences that lead to variability in the electric field (E-field) induced in the cortex. Here, we tested whether the variability in the E-field in the stimulated cortex during anodal tDCS, estimated using computational simulations, explains the variability in tDCS induced changes in GABA, a neurophysiological marker of stimulation effect. Methods Data from five previously conducted MRS studies were combined. The anode was placed over the left primary motor cortex (M1, 3 studies, N = 24) or right temporal cortex (2 studies, N = 32), with the cathode over the contralateral supraorbital ridge. Single voxel spectroscopy was performed in a 2x2x2cm voxel under the anode in all cases. MRS data were acquired before and either during or after 1 mA tDCS using either a sLASER sequence (7T) or a MEGA-PRESS sequence (3T). sLASER MRS data were analysed using LCModel, and MEGA-PRESS using FID-A and Gannet. E-fields were simulated in a finite element model of the head, based on individual structural MR images, using SimNIBS. Separate linear mixed effects models were run for each E-field variable (mean and 95th percentile; magnitude, and components normal and tangential to grey matter surface, within the MRS voxel). The model included effects of time (pre or post tDCS), E-field, grey matter volume in the MRS voxel, and a 3-way interaction between time, E-field and grey matter volume. Additionally, we ran a permutation analysis using PALM to determine whether E-field anywhere in the brain, not just in the MRS voxel, correlated with GABA change. Results In M1, higher mean E-field magnitude was associated with greater anodal tDCS-induced decreases in GABA (t(24) = 3.24, p = 0.003). Further, the association between mean E-field magnitude and GABA change was moderated by the grey matter volume in the MRS voxel (t(24) = −3.55, p = 0.002). These relationships were consistent across all E-field variables except the mean of the normal component. No significant relationship was found between tDCS-induced GABA decrease and E-field in the temporal voxel. No significant clusters were found in the whole brain analysis. Conclusions Our data suggest that the electric field induced by tDCS within the brain is variable, and is significantly related to anodal tDCS-induced decrease in GABA, a key neurophysiological marker of stimulation. These findings strongly support individualised dosing of tDCS, at least in M1. Further studies examining E-fields in relation to other outcome measures, including behaviour, will help determine the optimal E-fields required for any desired effects

Document Image Binarization and Segmentation

Conceptually the Binarization of the chronicled archives is NP-difficult issue since the picture contains commotion, source debasements, and enlightenment. The point of binarization is to locate the best possible picture pixels' limit to enhance the general execution of the framework. This paper presents another half and half meta-heuristic calculation to decide the best edge an incentive for picture archives binarization. The point of Binarization is to locate the correct picture pixels' limit to enhance the general execution of the framework. Record division is a strategy for ripping the archive into unmistakable areas. In this proposed framework at first we displaying Wavelet deterioration and to binarize the record picture, and furthermore utilizes the projection profile to section lines and associated part investigation to fragment the characters. The normal result will be the binarized and fragmented characters, these character can be bolster to OCR for acknowledgement

As Standing Task Difficulty Increases, Corticospinal Excitability Increases in Proportion to COP velocity but M1 Excitability Changes are Participant-Specific:Corticospinal and M1 Excitability in Standing

Reductions in the base of support (BOS) make standing difficult and require adjustments in the neural control of sway. In healthy young adults, we determined the effects of reductions in mediolateral (ML) BOS on peroneus longus (PL) motor evoked potential (MEP), intracortical facilitation (ICF), short interval intracortical inhibition (SICI) and long interval intracortical inhibition (LICI) using transcranial magnetic stimulation (TMS). We also examined whether participant-specific neural excitability influences the responses to increasing standing difficulty. Repeated measures ANOVA revealed that with increasing standing difficulty MEP size increased, SICI decreased (both p < 0.05) and ICF trended to decrease (p = 0.07). LICI decreased only in a sub-set of participants, demonstrating atypical facilitation. Spearman’s Rank Correlation showed a relationship of ρ = 0.50 (p = 0.001) between MEP size and ML center of pressure (COP) velocity. Measures of M1 excitability did not correlate with COP velocity. LICI and ICF measured in the control task correlated with changes in LICI and ICF, i.e., the magnitude of response to increasing standing difficulty. Therefore, corticospinal excitability as measured by MEP size contributes to ML sway control while cortical facilitation and inhibition are likely involved in other aspects of sway control while standing. Additionally, neural excitability in standing is determined by an interaction between task difficulty and participant-specific neural excitabilit