modified entropy
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Author(s):  
Umesh Kumar Sharma ◽  
Vandna Srivastava

Within the framework of quantum gravity and modified entropy-area formalism, the Tsallis holographic dark energy is an effort to peep into a mysterious content of the Universe, the dark energy, to analyze its nature. The Tsallis parameter [Formula: see text] provides the main characteristic of the Tsallis holographic dark energy. Opting the value of Tsallis parameter [Formula: see text], a quintessence scalar field description of the Tsallis holographic dark energy model can be obtained. In this work, we present this quintessential explanation of the Tsallis holographic dark energy with [Formula: see text] and reconstruct the dynamics of the scalar field and the potential of quintessence.


2021 ◽  
Vol 217 ◽  
pp. 104423
Author(s):  
O. Valencia ◽  
M.C. Ortiz ◽  
M.S. Sánchez ◽  
L.A. Sarabia

F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 214
Author(s):  
Yuichi Nishikawa ◽  
Kohei Watanabe ◽  
Naoya Orita ◽  
Noriaki Maeda ◽  
Hiroaki Kimura ◽  
...  

Background: Despite the potential benefits, the effects of Hybrid Assistive Limb (HAL) gait training on changes in neuromuscular activation that accompany functional gains in individuals with spinal muscular atrophy (SMA) type III is not well known. In this article, we quantify the effects of HAL gait training on spatial muscle activity patterns in a patient with SMA type III using multi-channel surface electromyography (SEMG). Methods: A 21-years old male (168 cm, 47.8 kg) with spinal muscular atrophy type III, when diagnosed at 18-years old by genetic screening, participated in this case study. Although he presented with forearm distal muscle weakness, atrophy of the intrinsic muscles of the hand, and neuromuscular fatigue, his activities of daily living is independent. The patient underwent a separate, single 33-minute session of both HAL and treadmill gait training. To evaluate the coefficient of variation (CoV) of force and alterations in the SEMG spatial distribution patterns, modified entropy and CoV of root mean square (RMS) were calculated from the vastus lateralis (VL) muscle before and after the intervention of HAL and treadmill gait training. Each training session was separated by a period of one month to avoid cross-over effects. Results: There was a greater decrease in the ΔCoV of force and an increase in the magnitude of whole VL muscle activation from pre-intervention to post-intervention with the HAL gait training as compared to the treadmill gait training. In response to only HAL gait training, the CoV of RMS was higher, and the modified entropy was lower post-intervention than pre-intervention. Conclusions: Our results support the notion that HAL gait training has a positive benefit on motor output not only in the magnitude of SEMG generated but also the patterns of neural activation.


F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 214
Author(s):  
Yuichi Nishikawa ◽  
Kohei Watanabe ◽  
Naoya Orita ◽  
Noriaki Maeda ◽  
Hiroaki Kimura ◽  
...  

Background: Despite the potential benefits, the effects of Hybrid Assistive Limb (HAL) gait training on changes in neuromuscular activation that accompany functional gains in individuals with spinal muscular atrophy (SMA) type III is not well known. In this article, we quantify the effects of HAL gait training on spatial muscle activity patterns in a patient with SMA type III using multi-channel surface electromyography (SEMG). Methods: A 21-years old male (168 cm, 47.8 kg) with spinal muscular atrophy type III, when diagnosed at 18-years old by genetic screening, participated in this case study. Although he presented with forearm distal muscle weakness, atrophy of the intrinsic muscles of the hand, and neuromuscular fatigue, his activities of daily living is independent. The patient underwent a separate, single 33-minute session of both HAL and treadmill gait training. To evaluate the coefficient of variation (CoV) of force and alterations in the SEMG spatial distribution patterns, modified entropy and CoV of root mean square (RMS) were calculated from the vastus lateralis (VL) muscle before and after the intervention of HAL and treadmill gait training. Each training session was separated by a period of one month to avoid cross-over effects. Results: There was a greater decrease in the ΔCoV of force and an increase in the magnitude of whole VL muscle activation from pre-intervention to post-intervention with the HAL gait training as compared to the treadmill gait training. In response to only HAL gait training, the CoV of RMS was higher, and the modified entropy was lower post-intervention than pre-intervention. Conclusions: Our results support the notion that HAL gait training has a positive benefit on motor output not only in the magnitude of SEMG generated but also the patterns of neural activation.


2021 ◽  
pp. 322-322
Author(s):  
Mengmeng Cui ◽  
Rui Song

As the pressure drop and pump power increase with the enhancement of heat transfer, it is of great value to investigate the comprehensive performance of the heat exchanger based on common accurate correlations of heat transfer and flow friction. This paper adopts a generalized air-side thermal-hydraulic correlation to study the comprehensive performances of the plate fin heat exchanger with wavy fins. To better understand the fin characteristics, performance indexes under the same flow rate, pressure drop and pump power are employed to estimate the comprehensive flow and heat transfer performances. The nonlinear optimization problem is established in consideration of the multiple independent variables with the maximum effectiveness or the minimum modified entropy generation number as the optimization objective function, which is solved by the genetic algorithm. Comparative analysis is conducted for results obtained from the parametric analysis and heat exchanger optimization, indicating that the objective function of the modified entropy generation number is effective for the design optimization of the comprehensive performance.


2020 ◽  
Vol 29 (15) ◽  
pp. 2050101
Author(s):  
Abdul Jawad ◽  
Iqra Siddique ◽  
Iarley P. Lobo ◽  
Wardat us Salam

In this paper, the thermodynamics of Reissner–Nordström-anti de Sitter black hole surrounded by quintessence is studied and the impact of the Gauss–Bonnet term is measured. The modified entropy, first law of thermodynamics and corresponding Smarr relation are derived due to the combined action of the Gauss–Bonnet term and quintessence fluid. We study the so-called black hole chemistry from the analysis of the corresponding equation-of-state, conjugate potential and the critical points in the extended phase space. To study the phase transitions, we plotted [Formula: see text], [Formula: see text] and [Formula: see text] diagrams and analyzed the conditions for the coexistence of phases.


Entropy ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. 935
Author(s):  
Juan F. García-Camacho ◽  
Gonzalo Ares de Parga ◽  
Karen Arango-Reyes ◽  
Encarnación Salinas-Hernández ◽  
Samuel Domínguez-Hernández

A modified expression of the electron entropy production in a plasma is deduced by means of the Kelly equations of state instead of the ideal gas equations of state. From the Debye–Hückel model which considers the interaction between the charges, such equations of state are derived for a plasma and the entropy is deduced. The technique to obtain the modified entropy production is based on usual developments but including the modified equations of state giving the regular result plus some extra terms. We derive an expression of the modified entropy production in terms of the tensorial Hermitian moments hr1…rm(m) by means of the irreducible tensorial Hermite polynomials.


2020 ◽  
Vol 29 (09) ◽  
pp. 2050064
Author(s):  
I. Díaz-Saldaña ◽  
J. C. López-Domínguez ◽  
M. Sabido

In this work, we study a Friedmann–Robertson–Walker (FRW) universe derived from a modified entropy–area relationship. By applying the first law of thermodynamics to the so-called apparent horizon and a modified entropy–area relationship, we obtain a modified Friedmann equation. Solving this model for a perfect fluid with vanishing cosmological constant, we find that for early times, the scale factor is the same as that of an FRW universe. In the late-time regime, although the cosmological constant is zero, the asymptotic behavior of the scale factor is exponential, and therefore, we can identify an effective cosmological constant. The origin of the effective cosmological constant can be traced to the modifications of the entropy–area relation.


Entropy ◽  
2020 ◽  
Vol 22 (6) ◽  
pp. 654
Author(s):  
Domenica Mirauda ◽  
Maria Grazia Russo

In narrow open channels, the three-dimensional nature of the flow and the transport momentum from the sidewalls to the central region cause the maximum longitudinal velocity to occur below the water surface. The entropy model is unable to accurately describe the velocities near the free surface when the dip phenomenon exists. The present paper proposes a new dip-modified entropy law for steady open channel flows, which consists of three additional terms: the first one similar to Coles’ function; the second one linearly proportional to the logarithmic distance from the free surface; and the third one depending on the cubic correction near the maximum velocity. The validity of the new model was tested on a set of laboratory measurements carried out in a straight rectangular flume with smooth boundaries and for different values of water discharge, bottom slope, and aspect ratio. A detailed error analysis showed good agreement with the data measured through the present research and a more accurate prediction of the velocity-dip-position compared with the one evaluated through the original entropy model. In addition, the modified entropy wake law matched very well with other literature data collected in rectangular cross-sections with different flow conditions.


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