Gurugram University

This work investigates the coupled thermo–electro–mechanical behavior of a piezo-semiconductor medium by integrating spatial nonlocality, temporal nonlocality, Kelvin–Voigt (KV) viscoelasticity, and memory-dependent derivatives into a unified analytical framework. The governing equations combine a Klein–Gordon (KG) type nonlocal operator with three-phase-lag heat conduction, semiconductor transport, and piezoelectric coupling, and are solved using the normal-mode approach. The analysis reveals that wave-field modifications remain highly concentrated within a thin boundary-interaction zone determined by the KG nonlocal parameters, where the competing effects of spatial nonlocality, temporal relaxation, KV viscosity, and memory-driven kernels jointly influence the penetration and strength of thermo–electro–mechanical responses. Spatial nonlocality suppresses the mechanical deformation and reduces the near-surface thermal amplitude, while simultaneously intensifying the coupled stress, carrier concentration, electric potential, and electric-displacement fields. Temporal relaxation mechanisms moderate these variations by redistributing amplitudes over depth and smoothing sharp spatial gradients. KV-viscosity significantly suppresses the electrical fields. By capturing the coupled roles of nonlocality, viscoelasticity, thermal relaxation, and memory-driven carrier–electromechanical interactions, the model provides a comprehensive basis for analyzing multiphysics wave behavior in piezoelectric semiconductor media relevant to SAW sensors, acousto-electronic components, transducers, and high-frequency signal-processing devices.

Introduction: A state of musculoskeletal equilibrium with little to no physical strain or stress is known as proper posture. While poor posture is caused by body parts that are not aligned with gravity, proper alignment with gravity lessens the strain on tissues. Reducing cardiovascular risks, mortality rates, and maintaining extended physical activity all depend on aerobic fitness. Aim: The current study aimed to investigate the effect of increasing severity of Forward Head Posture (FHP) on aerobic fitness of young adults between 18-25 years of age therefore, depicting their cardiovascular status. Materials and Methods: The present cross-sectional observational study was carried out over the course of six months from Feb 2020 to August 2020 at the Rehabilitation Centre of Jamia Hamdard, Hamdard Nagar, New Delhi, India. It evaluated the cardiovascular fitness levels of 82 college students over the course of six months using the 3-minute step test and FHP utilising University of Texas Health Science Center at San Antonio, (UTHSCA) 3.0. Healthy adults (Male: 41: Female: 41; Mean BMI: 48.2 +/- 5 kg; Mean age: 21.32 +/- 5 years for females, 20.58 +/- 5 years for males) from a variety of university courses who did not appear to have a history of lower limb injuries, cardiopulmonary disease, congenital malformations, neurological disorders, balance and proprioception issues, or cervical/thoracic spine trauma, were included in the study. The 3-minute step test was used to gauge aerobic fitness by measuring oxygen intake and endurance capacity during resting levels, 15 and 30 seconds post the completion of test, and the photogrammetric method of postural evaluation was used to measure postural misalignment. Results: The results showed a positive relationship between reduced aerobic fitness and the degree of FHP, especially in female students with a p-value of 0.0525 for the resting pulse rate, p=0.530 for the 15-second post-test, and p=0.039 for the 30-second post-test. According to the findings, bad posture may be associated with a decrease in cardiovascular endurance. It also depicted no statistically significant differences for males with a p-values of 0.325, 0.306 and 0.933 for resting pulse rate, post 15 seconds and 30 seconds of test, respectively for males. Conclusion: According to the study, maintaining good posture and reaching appropriate fitness levels is crucial, particularly for young people who are more likely to lead sedentary lives. More research is encouraged to examine the wider consequences of FHP on fitness and health, given its detrimental impacts.

In this study, we investigate the wCDM dynamical dark energy model with spatial curvature utilizing the recently released DESI Collaboration data (DR1 and DR2) in conjunction with other observational probes such as BBN, Observational Hubble Data (OHD), and Pantheon Plus (PP). Our investigation attempts to discover which DESI dataset gives a better match to the wCDM framework and assess the impact of spatial curvature on cosmological constraints. We find that the cosmic curvature parameter, Omega k, disfavors the cosmological constant for the DR2+BBN and DR2+BBN+OHD data combinations. However, the deviation from the cosmological constant remains below the 1 sigma level, indicating a mild preference for a open universe. In contrast, when using the DR1 based combinations namely DR1+BBN and DR1+BBN+OHD-the deviation from the cosmological constant increases to approximately 1.2 sigma, suggesting a slightly stronger indication of a open geometry. Also, the best-fit values of the Hubble constant (H0) obtained from the DR1+BBN+OHD+PP and DR2+BBN+OHD+PP combinations within the dynamical dark energy model are consistent with the results reported by the Planck Collaboration. Our findings provide constraints on the dark energy EoS parameter w0, reveal a mild but notable deviation from the vacuum energy (w = -1) scenario at a significance level 1.8 sigma from DR2+BBN+OHD+PP and 0.5 sigma from DR1+BBN+OHD+PP, both favoring the quintessence region of dark energy. Furthermore, the key physical distance measures DH, DV, and DM show better consistency with our model when analyzed with the DR2 data.

The ΛCDM model has long served as the cornerstone of modern cosmology, offering an elegant and successful framework for interpreting a wide range of cosmological observations. However, the rise of high-precision datasets has revealed statistically significant tensions, most notably the Hubble tension and the S_8 discrepancy, which challenge the completeness of this standard model. In this context, we explore the Λ_ sCDM model-an extension of ΛCDM featuring a single additional parameter, z_†, corresponding to a sign-switching cosmological constant. This minimal modification aims to alleviate key observational tensions without compromising the model's overall coherence. Recent findings present in the literature indicate that the Λ_ sCDM model not only provides a better fit to Lyman-α forest data for z_† < 2.3, but also accommodates both the SH0ES measurement of H_0 and the angular diameter distance to the last scattering surface when 2D BAO data are included. We present a comprehensive analysis combining the full Planck 2018 CMB data, the Pantheon Type Ia Supernovae sample, and the recently released Baryon Acoustic Oscillation (BAO) measurements from the Dark Energy Spectroscopic Instrument (DESI). Our finding reveal that the Preliminary DESI results, a possible 3.9σ deviation from ΛCDM expectations, reinforce the importance of exploring such dynamic dark energy frameworks. In sum, our study underscores the potential of Λ_ sCDM to reconcile multiple cosmological tensions and sheds light on the role of upcoming high-precision observations in reshaping our understanding of the universe's expansion history and the nature of dark energy.

In recent years, modifications to General Relativity (GR) have been explored to address cosmological observations, particularly in the context of late-time cosmic acceleration. Among these, modifications based on the Teleparallel Equivalent of General Relativity (TEGR), particularly f(T) gravity, have gained significant attention. In this work, we investigate the scalar perturbations in f(T) gravity, focusing on how these perturbations modify the Poisson and lensing equations and how they impact cosmological observables. By incorporating observational data from cosmic chromatometers, Big Bang nucleosynthesis, the DESI BAO survey, and Type Ia Supernovae (SNe Ia), we derive constraints on the parameters of the f(T) power-law model. Our results suggest that f(T) gravity can effectively alleviate some of the tensions observed in the standard ΛCDM model, including the Hubble constant (H_0) discrepancy. Furthermore, the evolution of the supernova luminosity and its dependence on the gravitational constant are considered to refine the measurement of cosmological parameters. The model's ability to address the H_0 tension is critically examined, and we find that f(T) gravity offers a viable alternative to the standard model. The work concludes by comparing the fits of the f(T) gravity model to the ΛCDM model using various information criteria, revealing key insights into the viability of modified gravity in contemporary cosmology.