Search

A subthreshold pulse of transcranial magnetic stimulation (TMS) on the motor cortex can modulate the amplitude of the monosynaptic reflex (H-reflex) elicited in the flexor carpi radialis (FCR) muscle, a method known as TMS-conditioning of the H-reflex. The purpose of this study was to establish the intersession reliability of this method over the course of three sessions. Eleven healthy participants received either peripheral nerve stimulation (PNS), TMS or a combination of the two. The intensity of the PNS stimuli was set to evoke a monosynaptic response (H-reflex) corresponding to 10 % of the maximum motor response (Mmax), HM10 %. The conditioning effect of TMS on the monosynaptic reflex was assessed by delivering subthreshold cortical pulses at different conditioning-test intervals (from -7 ms to 7 ms) from peripheral nerve stimulation. The first interval at which facilitation could be observed was deemed early facilitation (EF). Using intraclass correlation coefficients (ICCs), we found excellent reliability for Mmax amplitudes (ICC = 0.98), HM10 % amplitudes (ICC = 0.85) and TMS-conditioned H-reflexes recorded at the interval following EF (EF + 2 ms) (ICC = 0.87). Good reliability (ICCs ranging from 0.67 to 0.77) was found for the other conditioning-test intervals. We conclude that TMS-conditioned H-reflexes are reliable parameters to assess the excitability of corticospinal circuits.

AA-6061 aluminum alloy is extensively used in automobile and aerospace industries due to its high strength-to-weight ratio. However, this material shows limited formability in age-hardened condition at room temperature. Therefore, a new forming method known as single point incremental forming (SPIF) to deform the sheet was adopted. The SPIF experiments and finite element method (FEM) simulation were performed to form the sheet into the desired conical shape. Digital image correlation (DIC) method was used to measure the major and minor strains post deformation experimentally, and results were compared with FEM results. Detailed microstructural study was performed to understand the deformation behavior of AA-6061 aluminum alloy sheets during SPIF. It is observed that plastic anisotropy has strong effect on microstructure and texture development in different directions of AA-6061 alloy sheet during SPIF. It is also observed that volume fraction of goss and S texture components remains stable, whereas volume fraction of cube and brass texture changes significantly.

A Bayesian approach to spatial filtering is presented, which is robust to uncertain or erroneous direction-of-arrival (DOA) information. The proposed framework aims to capture multiple sound sources at each time-frequency instant with an arbitrary direction-dependent gain, while attenuating diffuse sound and noise. For robustness, the DOA corresponding to each sound source is assumed to be a discrete random variable with a prior defined on a discrete set of candidate DOAs over the whole DOA space. With this assumption, the desired spatial filter is given as a weighted sum of spatial filters corresponding to a specific combination of probable DOA values, where the weights are given by the joint posterior probabilities of the combination of DOA values. Assuming the whole DOA space as the support for each random variable results in redundant computations and contributes to a high computational cost. To alleviate this problem, a narrowband DOA estimate-based posterior proba bility approximation method is proposed, which isolates regions in the DOA space with high probability of containing the actual source DOAs to compute timeadaptive supports for each random variable. Through experimental analysis, we demonstrate the robustness of the proposed framework againstDOAestimation errors. Experimental evaluation with simulated and measured room impulse responses, in terms of objective performance measures, demonstrates the effectiveness of the framework to perform spatial filtering in noisy and reverberant acoustic environments.

A set of 20 diverse accessions of bottle gourd (Lagenaria siceraria (Molina) Standl.), exhibited wide range of variability for qualitative and quantitative traits. The seed oil content ranged from 18.6 % (IC446598) to 28.0 % (IC446592). The fatty acid composition of bottle gourd seed oil also varied. Days to 50% flowering and peduncle length had significant positive correlation with seed oil content, whereas inter nodal length had significant negative correlation. The intermodal length and number of primary branches per plant had high positive direct effect on fruit yield per plant. Based on the traits, the accessions clustered into three distinct clusters. The diversity may be exploited for crop improvement and the potential of bottle gourd as edible oil source further explored.

We analyze the conditions for numerical instability in the solution of a linearly constrained minimum variance (LCMV) beamformer with multiple directional constraints for a uniform linear array. An analytic expression is presented to determine the frequencies (for broadband signals such as speech) where the inverse term in the solution of the LCMV beamformer does not exist. Simulation results and power patterns are provided to further illustrate the problem. In addition, we investigate and discuss possible solutions to the problem.

The paper presents a generalized understanding on the dynamics of the sliding variable for discrete time sliding mode control systems via a fresh approach involving several bands in the space of the sliding variable. Using this analysis, controller parameters can be obtained once the ultimate band is chosen. It is shown that on choosing the least ultimate band, the control becomes non-switching and Gao's reaching law becomes identical to Utkin's reaching law. On other occasions, the ultimate band obtained using this approach is clearly less than that obtained in previous works using Gao's reaching law. The analysis is presented for both state feedback and multirate output feedback cases.