Fatiguing Effects of Indirect Vibration Stimulation in Upper Limb Muscles- pre, post and during Isometric Contractions Superimposed on Upper Limb Vibration

© 2019 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/ , which permits unrestricted use, provided the original author and source are credited.Whole-body vibration and upper limb vibration (ULV) continue to gain popularity as exercise intervention for rehabilitation and sports applications. However, the fatiguing effects of indirect vibration stimulation are not yet fully understood. We investigated the effects of ULV stimulation superimposed on fatiguing isometric contractions using a purpose developed upper limb stimulation device. Thirteen healthy volunteers were exposed to both ULV superimposed to fatiguing isometric contractions (V) and isometric contractions alone Control (C). Both Vibration (V) and Control (C) exercises were performed at 80% of the maximum voluntary contractions. The stimulation used was 30 Hz frequency of 0.4 mm amplitude. Surface-electromyographic (EMG) activity of the Biceps Brachii, Triceps Brachii and Flexor Carpi Radialis were measured. EMG amplitude (EMGrms) and mean frequency (MEF) were computed to quantify muscle activity and fatigue levels. All muscles displayed significantly higher reduction in MEFs and a corresponding significant increase in EMGrms with the V than the Control, during fatiguing contractions (p < 0.05). Post vibration, all muscles showed higher levels of MEFs after recovery compared to the control. Our results show that near-maximal isometric fatiguing contractions superimposed on vibration stimulation lead to a higher rate of fatigue development compared to the isometric contraction alone in the upper limb muscles. Results also show higher manifestation of mechanical fatigue post treatment with vibration compared to the control. Vibration superimposed on isometric contraction not only seems to alter the neuromuscular function during fatiguing efforts by inducing higher neuromuscular load but also post vibration treatment.Peer reviewedFinal Published versio

Deviations from Matthiessen rule and resistivity saturation effects in Gd and Fe

According to earlier first-principles calculations, the spin-disorder contribution to the resistivity of rare-earth metals in the paramagnetic state is strongly underestimated if Matthiessen's rule is assumed to hold. To understand this discrepancy, the resistivity of paramagnetic Fe and Gd is evaluated by taking into account both spin and phonon disorder. Calculations are performed using the supercell approach within the linear muffin-tin orbital method. Phonon disorder is modeled by introducing random displacements of the atomic nuclei, and the results are compared with the case of fictitious Anderson disorder. In both cases the resistivity shows a nonlinear dependence on the square of the disorder potential, which is interpreted as a resistivity saturation effect. This effect is much stronger in Gd than in Fe. The non-linearity makes the phonon and spin-disorder contributions to the resistivity non-additive, and the standard procedure of extracting the spin-disorder resistivity by extrapolation from high temperatures becomes ambiguous. An "apparent" spin-disorder resistivity obtained through such extrapolation is in much better agreement with experiment compared to the results obtained by considering only spin disorder. By analyzing the spectral function of the paramagnetic Gd in the presence of Anderson disorder, the resistivity saturation is explained by the collapse of a large area of the Fermi surface due to the disorder-induced mixing between the electronic and hole sheets.Comment: 9 pages, 7 figure

Spectral signatures of thermal spin disorder and excess Mn in half-metallic NiMnSb

Effects of thermal spin disorder and excess Mn on the electronic spectrum of half-metallic NiMnSb are studied using first-principles calculations. Temperature-dependent spin disorder, introduced within the vector disordered local moment model, causes the valence band at the $\Gamma$ point to broaden and shift upwards, crossing the Fermi level and thereby closing the half-metallic gap above room temperature. The spectroscopic signatures of excess Mn on the Ni, Sb, and empty sites (Mn$_\mathrm{Ni}$, Mn$_\mathrm{Sb}$, and Mn$_\mathrm{E}$) are analyzed. Mn$_\mathrm{Ni}$ is spectroscopically invisible. The relatively weak coupling of Mn$_\mathrm{Sb}$ and Mn$_\mathrm{E}$ spins to the host strongly deviates from the Heisenberg model, and the spin of Mn$_\mathrm{E}$ is canted in the ground state. While the half-metallic gap is preserved in the collinear ground state of Mn$_\mathrm{Sb}$, thermal spin disorder of the weakly coupled Mn$_\mathrm{Sb}$ spins destroys it at low temperatures. This property of Mn$_\mathrm{Sb}$ may be the source of the observed low-temperature transport anomalies.Comment: 5 pages, 7 figures, updated version with minor revisions and an additional figure, accepted in Phys. Rev. B (Rapid Communication

Grub Density of Lepidiota mansueta (Coleoptera: Scarabaeidae) in Different Habitats of the Majuli River Island of Assam, India

Grub density of Lepidiota mansueta beetle was assessed in five ecologically different habitats viz., open grassland; open cultivated land; cultivated field near tree; grassland near stream and cultivated land near stream on the basis of soil sampling carried out in five selected villages of the Majuli river island of Assam. Highest mean density of grub (8.0 and 6.5/m3) was recovered from grasslands near stream, followed by open grassland (4.6 and 4.7/m3), cultivated field near stream (1.8 and 1.4/m3), open cultivated field (1.1 and 1.2/ m3) and cultivated field near tree (1.0 and 1.2/m3) during 2011 and 2012, respectively. Fortnightly soil sampling conducted in grassland and cultivated land revealed that grubs of L. mansueta were confined in the upper most layer of soil (0–20 cm depth) during summer season (April–September) and moved to deeper soil layers during winter season (October–March). Majority of the grubs (81.83 per cent in grassland and 72.73 per cent in cultivated land) were recorded within the top 20 cm of soil. However, no grubs were noticed beyond 40 cm of soil depth

SVM and ANN Based Classification of Plant Diseases Using Feature Reduction Technique

Computers have been used for mechanization and automation in different applications of agriculture/horticulture. The critical decision on the agricultural yield and plant protection is done with the development of expert system (decision support system) using computer vision techniques. One of the areas considered in the present work is the processing of images of plant diseases affecting agriculture/horticulture crops. The first symptoms of plant disease have to be correctly detected, identified, and quantified in the initial stages. The color and texture features have been used in order to work with the sample images of plant diseases. Algorithms for extraction of color and texture features have been developed, which are in turn used to train support vector machine (SVM) and artificial neural network (ANN) classifiers. The study has presented a reduced feature set based approach for recognition and classification of images of plant diseases. The results reveal that SVM classifier is more suitable for identification and classification of plant diseases affecting agriculture/horticulture crops

Accuracy of the implant impression obtained from different impression materials and techniques: review

With the predictable integration of implants, the emphasis is shifted towards precise prosthesis. Reproducing the intraoral relationship of implants through impression procedures is the first step in achieving an accurate, passively fitting prosthesis. The critical aspect is to record the three dimensional orientation of the implant as it is present intraorally, other than reproducing fine surface detail for successful implant prosthodontic treatment. The development of impression techniques to accurately record implant position has become more complicated and challenging. During the prosthetic phase of implant therapy there are numerous options available to the implantologist in relation to different impression techniques and materials available for impression making. It is critical to ensure that implant – prosthesis interface have passive fit and original position of the implant maintained in the master cast. There is no evidence supporting that one impression technique or material is better than the other. In the present article the various parameters affecting the accuracy of implant impression along with impression material and technique pertaining to different clinical situations is reviewed

Deviations from Matthiessen’s rule and resistivity saturation effects in Gd and Fe from first principles

According to earlier first-principles calculations, the spin-disorder contribution to the resistivity of rare-earth metals in the paramagnetic state is strongly underestimated if Matthiessen’s rule is assumed to hold. To understand this discrepancy, the resistivity of paramagnetic Fe and Gd is evaluated by taking into account both spin and phonon disorder. Calculations are performed using the supercell approach within the linear muffin-tin orbital method. Phonon disorder is modeled by introducing random displacements of the atomic nuclei, and the results are compared with the case of fictitious Anderson disorder. In both cases, the resistivity shows a nonlinear dependence on the square of the disorder potential, which is interpreted as a resistivity saturation effect. This effect is much stronger in Gd than in Fe. The nonlinearity makes the phonon and spin-disorder contributions to the resistivity nonadditive, and the standard procedure of extracting the spin-disorder resistivity by extrapolation from high temperatures becomes ambiguous. An “apparent” spin-disorder resistivity obtained through such extrapolation is in much better agreement with experiment compared to the results obtained by considering only spin disorder. By analyzing the spectral function of the paramagnetic Gd in the presence of Anderson disorder, the resistivity saturation is explained by the collapse of a large area of the Fermi surface due to the disorder-induced mixing between the electron and hole sheets