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In this communication, we have explored spatially homogeneous, anisotropic Bianchi-II space-time in f(R, T) theory of gravity. Here, we have obtained an explicit solution of the field equations of f(R, T) theory with time dependent fractional linear varying deceleration parameter (FLVDP) i.e. q(t) . The accelerating expanding nature of the cosmos has been also discussed under the suitable assumption q ( t ) = α ( 1 − t ) 1 + t , here α > 0. It is observed that the universe was originated from a singularity in the past and is expanding at an accelerating rate. The FLVDP depicts a transitional phase i.e., early deceleration to the current accelerating phase.

The dynamics of an isothermal gas suspension is studied. A spherically symmetric stationary submodel is derived and partially integrated. In a barochronous case, this submodel is fully integrated and results are discussed. Different modes of motion are analytically described in the barochronous case. The interpretation of the solutions is proposed. We highlight three essentially different modes of motion. In the first mode, we have a dispersion of gas suspension from the origin with a relaxation of velocities and leading to the uniform motion. In the second mode, phases focus in the origin with finite nonzero velocities and infinitely increasing densities. In the third mode, phases are interpenetrating to each other and decelerating due to the friction force, that leads to an accumulation of particles and an unlimited increase of densities in different nonzero raduises with zero velocities.

Purpose Increased vagal activity plays a prominent role in vasovagal syncope (VVS). The aim of this study was to characterize vagal function in VVS by evaluating the heart rate (HR) deceleration capacity (DC) and the HR deceleration runs (DRs) in patients with VVS between attacks. Methods A total of 188 consecutive VVS patients were enrolled in the study, of whom 129 had positive head-up tilt test (HUTT); 132 healthy participants were enrolled as controls. DC, DRs (DR2, i.e., episodes of 2 consecutive beat-to-beat HR decelerations), and the sum of DR8-10 (very long DR [VLDR]) were calculated using 24-h electrograms. Clinical characteristics, DC, and DRs were compared among syncope groups and controls. Results Patients with VVS had higher DC (10.63 ± 2.1 vs. 6.58 ± 1.7 ms; P  < 0.001) and lower minimum HR and DR6-10 than controls. No significant differences in DC or DR6-10 were found between the patients with positive and those with negative HUTT results. In multivariate logistic regression analysis, minimum HR ≥ 40 bpm (odds ratio [OR] 0.408, 95% confidence interval [CI] 0.167–0.989; P  = 0.048), daytime DC ≥ 7.37 ms (OR 3.040, 95% CI 1.220–7.576; P  = 0.013), and VLDR ≥ 0.046% (OR 0.306, 95% CI 0.138–0.679; P  = 0.004) were demonstrated to be risk factors significantly associated with VVS. Conclusion Compared to healthy controls, patients with VVS demonstrated distinct HR deceleration profiles between attacks, including overall higher DC and lower DR6-10.

Polydopamine is a biomimetic self-adherent polymer, which can be easily deposited on a wide variety of materials. Despite the rapidly increasing interest in polydopamine-based coatings, the polymerization mechanism and the key intermediate species formed during the deposition process are still controversial. Herein, we report a systematic investigation of polydopamine formation on halloysite nanotubes; the negative charge and high surface area of halloysite nanotubes favour the capture of intermediates that are involved in polydopamine formation and decelerate the kinetics of the process, to unravel the various polymerization steps. Data from X-ray photoelectron and solid-state nuclear magnetic resonance spectroscopies demonstrate that in the initial stage of polydopamine deposition, oxidative coupling reaction of the dopaminechrome molecules is the main reaction pathway that leads to formation of polycatecholamine oligomers as an intermediate and the post cyclization of the linear oligomers occurs subsequently. Furthermore, TRIS molecules are incorporated into the initially formed oligomers. Polydopamine is a biomimetic self-adherent polymer, which can be easily deposited on a wide variety of materials but the polymerization mechanism and the key intermediate species formed during the deposition process are still controversial. Here, the authors report a systematic investigation of polydopamine formation on halloysite nanotubes.

Quantifying the dynamics of land use change is critical in tackling global societal challenges such as food security, climate change, and biodiversity loss. Here we analyse the dynamics of global land use change at an unprecedented spatial resolution by combining multiple open data streams (remote sensing, reconstructions and statistics) to create the HIstoric Land Dynamics Assessment + (HILDA +). We estimate that land use change has affected almost a third (32%) of the global land area in just six decades (1960-2019) and, thus, is around four times greater in extent than previously estimated from long-term land change assessments. We also identify geographically diverging land use change processes, with afforestation and cropland abandonment in the Global North and deforestation and agricultural expansion in the South. Here, we show that observed phases of accelerating (~1960–2005) and decelerating (2006–2019) land use change can be explained by the effects of global trade on agricultural production. Quantifying land use change is critical in tackling global challenges related to food, climate and biodiversity. Here the authors show that land use change has affected 32 % of the global land area in six decades (1960- 2019) by combining multiple open datasets to create the HIstoric Land Dynamics Assessment +.

If a star gets too close to a supermassive black hole, it gets ripped apart in a tidal disruption event (TDE). Mattila et al. discovered a transient source in the merging galaxy pair Arp 299, which they interpret as a TDE. The optical light is hidden by dust, but the TDE generated copious infrared emission. Radio observations reveal that a relativistic jet was produced as material fell onto the black hole, with the jet expanding over several years. The results elucidate how jets form around supermassive black holes and suggest that many TDEs may be missed by optical surveys. Science , this issue p. 482 A relativistic radio jet is seen switching on after a star is ripped apart by a black hole. Tidal disruption events (TDEs) are transient flares produced when a star is ripped apart by the gravitational field of a supermassive black hole (SMBH). We have observed a transient source in the western nucleus of the merging galaxy pair Arp 299 that radiated >1.5 × 10 52 erg at infrared and radio wavelengths but was not luminous at optical or x-ray wavelengths. We interpret this as a TDE with much of its emission reradiated at infrared wavelengths by dust. Efficient reprocessing by dense gas and dust may explain the difference between theoretical predictions and observed luminosities of TDEs. The radio observations resolve an expanding and decelerating jet, probing the jet formation and evolution around a SMBH.

People increasingly seek out opportunities to escape from a sped-up pace of life by engaging in slow forms of consumption. Drawing from the theory of social acceleration, we explore how consumers can experience and achieve a slowed-down experience of time through consumption. To do so, we ethnographically study the Camino de Santiago pilgrimage in Spain and introduce the concept of consumer deceleration. Consumer deceleration is a perception of a slowed-down temporal experience achieved via a decrease in certain quantities (traveled distance, use of technology, experienced episodes) per unit of time through altering, adopting, or eschewing forms of consumption. Consumers decelerate in three ways: embodied, technological, and episodic. Each is enabled by consumer practices and market characteristics, rules, and norms, and results in time being experienced as passing more slowly and as being an abundant resource. Achieving deceleration is challenging, as it requires resynchronization to a different temporal logic and the ability to manage intrusions from acceleration. Conceptualizing consumer deceleration allows us to enhance our understanding of temporality and consumption, embodied consumption, extraordinary experiences, and the theory of social acceleration. Overall, this study contributes to consumer research by illuminating the role of speed and rhythm in consumer culture.

The present study deals with the investigation of the Friedmann-Lemaitre-Robertson-Walker models (often FLRW-models) with time varying G and ∧ in the framework of General theory of Relativity. The Einstein field equations have been solved by considering the time-varying deceleration parameter q(t) and Scale factor α ( t ) = e β t + ( sinh β t ) 1 m , where m and β are arbitrary constants. We have analysed the value of m , which will generate a transition for universe from early decelerating phase to recent acceleration phase. The physical and graphic behaviour have also been planned to study in this communication.

Strong light–matter interaction in cavity environments is emerging as a promising approach to control chemical reactions in a non-intrusive and efficient manner. The underlying mechanism that distinguishes between steering, accelerating, or decelerating a chemical reaction has, however, remained unclear, hampering progress in this frontier area of research. We leverage quantum-electrodynamical density-functional theory to unveil the microscopic mechanism behind the experimentally observed reduced reaction rate under cavity induced resonant vibrational strong light-matter coupling. We observe multiple resonances and obtain the thus far theoretically elusive but experimentally critical resonant feature for a single strongly coupled molecule undergoing the reaction. While we describe only a single mode and do not explicitly account for collective coupling or intermolecular interactions, the qualitative agreement with experimental measurements suggests that our conclusions can be largely abstracted towards the experimental realization. Specifically, we find that the cavity mode acts as mediator between different vibrational modes. In effect, vibrational energy localized in single bonds that are critical for the reaction is redistributed differently which ultimately inhibits the reaction. Hybridization of dark optical cavity modes with vibrational states of molecules can alter chemical reactions. Here, the authors use ab-initio methods to shine light on the associated mechanism and highlight the role of the optical mode to redistribute the vibrational energy.

We propose an extension of the symmetric teleparallel gravity, in which the gravitational action L is given by an arbitrary function f of the non-metricity Q and of the trace of the matter-energy-momentum tensor T, so that \\[L=f(Q,T)\\]. The field equations of the theory are obtained by varying the gravitational action with respect to both metric and connection. The covariant divergence of the field equations is obtained, with the geometry–matter coupling leading to the nonconservation of the energy-momentum tensor. We investigate the cosmological implications of the theory, and we obtain the cosmological evolution equations for a flat, homogeneous and isotropic geometry, which generalize the Friedmann equations of general relativity. We consider several cosmological models by imposing some simple functional forms of the function f(Q, T), corresponding to additive expressions of f(Q, T) of the form \\[f(Q,T)=\\alpha Q+\\beta T\\], \\[f(Q,T)=\\alpha Q^{n+1}+\\beta T\\], and \\[f(Q,T)=-\\alpha Q-\\beta T^2\\]. The Hubble function, the deceleration parameter, and the matter-energy density are obtained as a function of the redshift by using analytical and numerical techniques. For all considered cases the Universe experiences an accelerating expansion, ending with a de Sitter type evolution. The theoretical predictions are also compared with the results of the standard \\[\\Lambda \\]CDM model.