60,440 research outputs found
Variability In The Ecoraces Of Tropical Tasar Sillkworm Antheraea Mylitta Drury
No full textTropical tasar silkworm, Antheraea mylitta Drury is exploited in countries for commercial silk production and improved varieties of these silkworms can be evolved by employing various breeding techniques. As the insect has established itself in various forms of ecological populations (Commonly called as ecoraces) in different geographical niches of the country depending on food plants and micro-environmental conditions available to them, the species exists in the form of nearly 44 ecoraces (Singh and Srivastava,1997, Srivastava,2002 and Srivastava et at. 2007) distributed over different states. However, due to free interbreeding in nature for centuries, the fauna is highly heterogeneous.

Tasar culture is a forest based industry being practiced as tradition, since time immemorial by the tribes of Central India, extending from West Bengal in the East to Karnataka in South. The species A. mylitta D. is polyphagous in nature. The present study comprises the ecoraces of tropical tasar silkworm of A. mylitta D. These ecoraces are mainly restricted in the tropical moist deciduous forest area where the average rainfall varies between 1200-2000 mm and the deciduous zone of the dry tropical forest area where the average rainfall has been observed to be about 1000 mm. The Primary food plants of the insects are Terminalia tomentosa, Terminalia arjuna and Shorea robusta and secondary food plants are Terminalia chebula, T. bellerica, T. peniculata, Zizyphus jujuba etc. The phenotypic and genotypic variability is very much prominent. The present review paper comprises the extent and degree of natural variation in tropical tasar silkworm A. mylitta D
Relationship of changes in strain rate indices estimated from velocity-encoded MR imaging to loss of muscle force following disuse atrophy
No full textPurpose: This study explores changes in strain rate (SR) (rate of regional deformation) parameters extracted from velocity-encoded MRI and their relationship to muscle force loss following 4-week unilateral lower limb suspension in healthy humans. Methods: Two-dimensional SR maps were derived from three directional velocity-encoded MR phase-contrast images of the medial gastrocnemius in seven subjects. Atrophy-related and regional differences in the SR eigenvalues, angle between the SR and muscle fiber (SR-fiber angle), and strain rates in the fiber basis were statistically analyzed using analysis of variance and linear regression. Results: During isometric contraction, SR in the fiber cross section (SRin-plane) was significantly lower, and the SR-fiber angle was significantly higher postsuspension (P < 0.05). On multiple variable regression analysis, the volume of medial gastrocnemius, SRin-plane, and SR-fiber angle were significantly associated with force and changes in the, and the SR eigenvalues and shear SR were significantly associated with change in force with disuse. Conclusions: Changes in SR-fiber angle, SRin-plane, and shear SR as well as their ability to predict force and force changes may reflect the role of remodeling of the extracellular matrix in disuse atrophy and its functional consequence in reducing lateral transmission of force. Magn Reson Med 79:912–922, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicin
Testing quantum foundations with quantum computers
No full textWe present two complementary viewpoints for combining quantum computers and the foundations of quantum mechanics. On the one hand, ideal devices can be used as test beds for experimental tests of the foundations of quantum mechanics: We provide algorithms for the Peres test for complex numbers in quantum superpositions and the Sorkin test of Born's rule. On the other hand, noisy intermediate-scale quantum devices can be benchmarked using these same tests. These are deep quantum benchmarks based on the foundations of quantum theory itself. We present test data from Rigetti hardware
A Dynamic Subfilter-scale Stress Model for Large Eddy Simulations Based on Physical Flow Scales
No full textWe propose a new definition of the length scale in an eddy-viscosity model for large-eddy simulations (LES). This formulation extends and generalizes a previous proposal [Piomelli, Rouhi and Geurts, Proc. ETMM10, 2014], in which the LES length scale was expressed in terms of the integral length-scale of turbulence determined by the flow characteristics and explicitly decoupled from the simulation grid; this approach was named Integral Length-Scale Approximation (ILSA). As in the original ILSA, the model coefficient was determined by the user, and required to maintain a desired contribution of the unresolved, subfilter scales (SFS) to the global transport. We propose a local formulation (local ILSA) in which the model coefficient is local in space, allowing a precise control over SFS activity as a function of location. This new formulation preserves the properties of the global model; application to channel flow and backward-facing step verifies its features and accuracy
Large-eddy simulation of a separated flow with a sub-filter scale model based on the integral length-scale
No full textA new sub-filter scale model for large-eddy simulations, which uses a length-scale proportional to the integral scale of the turbulence instead of the grid resolution to parametrize the modelled stresses, will be assessed in the prediction of the flow of a boundary-layer over a rough surface, which includes separation and reattachment
Role of the Extracellular Matrix in Loss of Muscle Force With Age and Unloading Using Magnetic Resonance Imaging, Biochemical Analysis, and Computational Models
No full textThe focus of this review is the application of advanced MRI to study the effect of aging and disuse related remodeling of the extracellular matrix (ECM) on force transmission in the human musculoskeletal system. Structural MRI includes (i) ultra-low echo times (UTE) maps to visualize and quantify the connective tissue, (ii) diffusion tensor imaging (DTI) modeling to estimate changes in muscle and ECM microstructure, and (iii) magnetization transfer contrast imaging to quantify the macromolecular fraction in muscle. Functional MRI includes dynamic acquisitions during contraction cycles enabling computation of the strain tensor to monitor muscle deformation. Further, shear strain extracted from the strain tensor may be a potential surrogate marker of lateral transmission of force. Biochemical and histological analysis of muscle biopsy samples can provide “gold-standard” validation of some of the MR findings. The review summarizes biochemical studies of ECM adaptations with age and with disuse. A brief summary of animal models is included as they provide experimental confirmation of longitudinal and lateral force transmission pathways. Computational muscle models enable exploration of force generation and force pathways and elucidate the link between structural adaptations and functional consequences. MR image findings integrated in a computational model can explain and predict subject specific functional changes to structural adaptations. Future work includes development and validation of MRI biomarkers using biochemical analysis of muscle tissue as a reference standard and potential translation of the imaging markers to the clinic to noninvasively monitor musculoskeletal disease conditions and changes consequent to rehabilitative interventions
Near Wall PIV-Measurements on the Windward Slope of a Hill
No full textThe turbulent flow over periodic hills was measured near to the wall, using planar Particle-Image-Velocimetry (PIV) at high spatial resolution. Our focus is on the near wall turbulence structure on the windward slope of the hill. For large-eddy simulation (LES) we suspect that, if this was not predicted accurately, it affects the prediction of the velocity profiles over the hill crest which in turn will affect the recirculation length downstream of the hill. Regarding the time averaged velocities, we were able to resolve the linear viscous region of the boundary layer. The velocity distribution and also the Reynolds stress does not comply with the law of the wall as it is valid for a turbulent boundary layer at equilibrium
Energy dissipation and flux laws for unsteady turbulence
No full textDirect Numerical Simulations of spatially periodic unsteady turbulence show that the high Reynolds number scalings of the instantaneous energy dissipation rate and interscale energy flux at intermediate wavenumbers are qualitatively different from the well-known cornerstone scalings of equilibrium turbulence where and are time-dependent rms velocity and integral length-scales. Instead, they both scale as where and are length and velocity scales characterizing initial/overall unsteady turbulence conditions
Studies of human arm movements using three joints: control strategies for a manipulator with redundant degrees of freedom
No full textDean J, Brüwer M, Steinkühler U, Cruse H. Studies of human arm movements using three joints: control strategies for a manipulator with redundant degrees of freedom. In: Gupta M, Sinha NK, eds. Intelligent Control Systems. IEEE Press; 1993
Direct numerical simulation of turbulent Couette-Poiseuille flow with zero skin friction
No full textThe near-wall scaling of mean velocity U(y) is addressed for the case of zero skin friction on one wall of a fully turbulent channel flow. The present DNS results can be added to the evidence in support of the conjecture that U is proportional to √yw in the region just above the wall at which the mean shear dU/dy = 0
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