39 research outputs found
Unsteady MHD free convection flow of casson fluid over an inclined vertical plate embedded in a porous media
No full textThe High-Energy Emission of Low-Mass Stars
No full textThe high-energy emission from low-mass stars is a product of stellar magnetism and turbulent convection as well as an input to the dynamics of planetary atmospheres. Observing this high-energy emission and understanding its formation are vital to understanding the physics of both stars and planets. One limitation to our knowledge of planetary atmospheric escape is the lack of observed extreme ultraviolet spectra for most stars, and to overcome this obstacle I present a method to use more accessible observations to infer the unobserved extreme ultraviolet. Then I measure the variability of emission from the upper layers of the stellar atmosphere for a number of stars across a range of rotation periods to characterize one aspect of how magnetic heating processes seem to collectively wane as stars age and spin down. That spin-down over time takes place after an initial phase of high activity during a star’s youth, an important period of time for early planetary evolution, and so I combine my method of extreme ultraviolet inference with existing studies of solar-type stars to estimate the cumulative irradiation of planets orbiting the young Solar analog V1298 Tau. Finally, I extend this approach of using stars across time and rotation period to map out how the high-energy spectrum evolves for M dwarfs, the most common type of star and exoplanet host.
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Analysis of basic motor behaviors in quadrupeds
No full textAbility to perform locomotion in different directions and maintain upright body posture is crucial for normal life. At present, mice, which allows employing genetic approaches, are widely used in studying the locomotor system. In these investigations different experimental setups are used to evoke locomotion. First aim of the present study was to compare kinematics of forward (FW) and backward (BW) locomotion performed in different environmental conditions (i.e. in a tunnel, on a treadmill and on an air-ball). On all set-ups, average speed, step amplitude and swing duration during BW locomotion were significantly smaller compared to those observed during FW locomotion. The extent of rostro-caudal paw trajectory in relation to the hip projection to the surface (HP) strongly depended on hip height. With high hip height, the trajectory was symmetrical in relation to HP (middle steps). When hip was low, steps were either displaced rostrally (anterior steps) or caudally (posterior steps) in relation to HP. During FW locomotion, predominantly anterior and posterior steps were observed, respectively, on the treadmill and air-ball, while all three stepping forms were observed in the tunnel. We observed only anterior steps during BW locomotion. Intralimb coordination depended on the form of stepping.Second aim of the present study was to reveal the role of two populations of commissural interneurons (V0V and V0D CINs) in control of a number of basic motor behaviours (BW locomotion, scratching, righting, and postural corrections). For this purpose two types of knockout mice (Vglut2Cre;Dbx1DTA mice and Hoxb8Cre;Dbx1DTA mice with only V0V and all V0 CINs ablated, respectively) as well as wild-type littermates were used. Our results suggest that the functional effect of excitatory V0V CINs during BW locomotion and scratching is inhibitory, and that execution of scratching involves active inhibition of the contralateral scratching CPG mediated by V0V CINs. By contrast, V0D CINs are elements of spinal postural network, generating postural corrections. Finally, both V0D and V0V CINs contribute to generation of righting behavior. Thus, our study shows the differential contribution of V0 neuron subpopulations in generation of diverse motor acts.Single steps in different directions are used for control of balance or body configuration. However, our knowledge about neural mechanisms responsible for their generation is limited. The third aim of the present study was to characterize postural response to disturbance of basic body configuration caused by forward, backward or outward displacement of the hindlimb. In intact rabbits, displacement of the hindlimb in any direction caused a postural response consisting of two components. First, a lateral trunk movement towards the supporting (contralateral) hindlimb was performed, and then a corrective step in the direction opposite to the direction of the initial limb displacement was executed. These two components were generated by different mechanisms activated in a strict order by sensory information from the deviated limb signalling distortion of the limb/limb-trunk configuration. We have shown that the integrity of the forebrain was not critical for generation of this postural response. We proposed a hypothesis about operation of mechanisms generating the postural response characterized in the present study.List of scientific papersI. Vemula M.G., Deliagina T.G., Zelenin P.V. (2019). Kinematics of forward and backward locomotion performed in different environmental conditions. J Neurophysiol. 122:2142-2155. https://doi.org/10.1152/jn.00239.2019 II. Zelenin P.V*., Vemula M.G*., Lyalka V.F., Talpalar A.E., Kiehn O., Deliagina T.G. Role of V0 commissural interneurons in control of basic motor behaviors. *Authors with equal contribution. [Manuscript]III. Hsu L.J., Zelenin P.V., Lyalka V.F., Vemula M.G., Orlovsky G.N., Deliagina T.G. (2017). Neural mechanisms of single corrective steps evoked in the standing rabbit. Neuroscience. 347:85-102. https://doi.org/10.1016/j.neuroscience.2017.02.007 </p
The High-Energy Emission of Low-Mass Stars
No full textThe high-energy emission from low-mass stars is a product of stellar magnetism and turbulent convection as well as an input to the dynamics of planetary atmospheres. Observing this high-energy emission and understanding its formation are vital to understanding the physics of both stars and planets. One limitation to our knowledge of planetary atmospheric escape is the lack of observed extreme ultraviolet spectra for most stars, and to overcome this obstacle I present a method to use more accessible observations to infer the unobserved extreme ultraviolet. Then I measure the variability of emission from the upper layers of the stellar atmosphere for a number of stars across a range of rotation periods to characterize one aspect of how magnetic heating processes seem to collectively wane as stars age and spin down. That spin-down over time takes place after an initial phase of high activity during a star’s youth, an important period of time for early planetary evolution, and so I combine my method of extreme ultraviolet inference with existing studies of solar-type stars to estimate the cumulative irradiation of planets orbiting the young Solar analog V1298 Tau. Finally, I extend this approach of using stars across time and rotation period to map out how the high-energy spectrum evolves for M dwarfs, the most common type of star and exoplanet host.
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Impact of tab location relative to the nozzle exit on the shock structure of a supersonic jet
No full textA study on the functional and radiological outcome with complications in the management of proximal humerus fractures operated with proximal humerus internal locking osteosynthesis system
No full textBackground: A number of opinions exist regarding the management of proximal humerus fractures starting from conservative to tension band-wiring to internal fixation with plates. The aim of this study is to assess the functional outcome, the radiological outcome and the complications associated with the management of proximal humerus fractures treated with proximal humerus interlocking osteosynthesis system (PHILOS).
Methods: A prospective descriptive study was undertaken comprising of 40 patients. Closed proximal humerus fractures meeting Neer’s criteria for operative displacement were enrolled. Patients underwent open reduction internal fixation with PHILOS plate. Post-operative radiological outcome was estimated with follow-up x-rays, functional outcome using the Constant and Murley score.
Results: 60% patients were female, with the most common mode of injury being fall at a ground level. Late complications were noted in 25% of patients, which were malunion 5%, joint stiffness 10%, joint instability 5% and heterotopic ossification 5%. The mean Constant and Murley score was 79.5 and it was found to be statistically significant to the type of fracture according to the Neer’s classification (Kruskal Wallis test, p=0.005). Joint stiffness was also found to be statistically significantly correlated to the type of fracture pattern (Chi square test, p=0.016). The average time to union was 10 weeks.
Conclusions: Thus, by this study it can be expressed due to appropriate articular reduction by open reduction and by the use of a fixed angle implant like the PHILOS plate, operative management of proximal humerus fractures by the said implant is a viable option to enable quick and early rehabilitation of patients
Attack Graphs for EPCglobal RFID
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A WiFi and Bluetooth Low-Energy Backscatter Combo Chip With Beam Steering Capabilities
No full textThis article introduces a dual-mode backscatter integrated circuit that supports both WiFi and Bluetooth low-energy (BLE) transmissions. It enables a multiantenna WiFi mode with reconfigurable beam steering of single-sideband (SSB) quadrature phase shift-keying (QPSK) signals, while also facilitating omnidirectional SSB BLE-to-BLE backscatter communication. To achieve beam steering, two techniques are proposed: 1) a transmission-line-less fully reflective SP4T backscatter switch is employed to minimize power loss and maximize the communication range and 2) a multiantenna array is constructed using the aforementioned SP4T switches together with a baseband phase-shifting technique to reradiate the incident WiFi signal with a controllable angle of direction. The chip implementation is based on a 65-nm CMOS process and operates at a power consumption of in standby mode. In backscattering mode, it consumes for the single-antenna approach and for the multiantenna approach. The proposed design achieves a worst-case access point (AP)-to-AP range of 35 and 56 m for the single-antenna and multiantenna approaches, respectively
