An exact master equation for the system-reservoir dynamics under the strong coupling regime and non-Markovian dynamics

In this paper we present a method to derive an exact master equation for a bosonic system coupled to a set of other bosonic systems, which plays the role of the reservoir, under the strong coupling regime, i.e., without resorting to either the rotating-wave or secular approximations. Working with phase-space distribution functions, we verify that the dynamics are separated in the evolution of its center, which follows classical mechanics, and its shape, which becomes distorted. This is the generalization of a result by Glauber, who stated that coherent states remain coherent under certain circumstances, specifically when the rotating-wave approximation and a zero-temperature reservoir are used. We show that the counter-rotating terms generate fluctuations that distort the vacuum state, much the same as thermal fluctuations.Finally, we discuss conditions for non-Markovian dynamics

Plasma nitric oxide in dogs with pulmonary hypertension secondary or not to left-sided heart disease

ABSTRACT Nitric oxide (NO) is an important mediator responsible for vasodilation in pulmonary hypertension (PH) in humans. Based on human literature, it is suggested that in dogs there is also NO production decrease in lung tissue in the presence of PH with hypoxia. Therefore, the aim of this research was to determine the indirect plasmatic NO concentration in dogs with PH secondary or not to the left-side heart disease (LHD) and also with low, intermediate and high probability of PH to characterize the NO involvement on PH in dogs. Blood samples were collected from 35 dogs with probability of PH to NO measurement. NO concentration was estimated by the nitrite/nitrate concentration, and it was significantly different (p=0.002) in dogs with PH secondary to LHD (median=14 µM, range 11.19-16.59) and not secondary to LHD (median=25.88µM, range 15.08-36.71). However, this was not significant for the probability of low, intermediate, and high PH, although there was a tendency for NO concentration to be higher in dogs with high PH. The results of this study demonstrate that there is release of NO in dogs with PH, as well as that its dosage could differentiate dogs with PH secondary to LHD from dogs with non-secondary PH

Melting a Hubbard dimer: benchmarks of 'ALDA' for quantum thermodynamics

The competition between evolution time, interaction strength, and temperature challenges our understanding of many-body quantum systems out-of-equilibrium. Here we consider a benchmark system, the Hubbard dimer, which allows us to explore all the relevant regimes and calculate exactly the related average quantum work. At difference with previous studies, we focus on the effect of increasing temperature, and show how this can turn competition between many-body interactions and driving field into synergy. We then turn to use recently proposed protocols inspired by density functional theory to explore if these effects could be reproduced by using simple approximations. We find that, up to and including intermediate temperatures, a method which borrows from ground-state adiabatic local density approximation improves dramatically the estimate for the average quantum work, including, in the adiabatic regime, when correlations are strong. However at high temperature and at least when based on the pseudo-LDA, this method fails to capture the counterintuitive qualitative dependence of the quantum work with interaction strength, albeit getting the quantitative estimates relatively close to the exact results

TRPV4 activates autonomic and behavioural warmth-defence responses in Wistar rats

Aim In this study, we aimed at investigating the involvement of the warmth-sensitive channel - TRPV4 (in vitro sensitive to temperatures in the range of approx. 24-34 degrees C) - on the thermoregulatory mechanisms in rats.MethodsWe treated rats with a chemical selective agonist (RN-1747) and two antagonists (RN-1734 and HC-067047) of the TRPV4 channel and measured core body temperature, metabolism, heat loss index and preferred ambient temperature.ResultsOur data revealed that chemical activation of TRPV4 channels by topical application of RN-1747 on the skin leads to hypothermia and this effect was blocked by the pre-treatment with the selective antagonist of this channel. Intracerebroventricular treatment with RN-1747 did not cause hypothermia, indicating that the observed response was indeed due to activation of TRPV4 channels in the periphery. Intravenous blockade of this channel with HC-067047 caused an increase in core body temperature at ambient temperature of 26 and 30 degrees C, but not at 22 and 32 degrees C. At 26 degrees C, HC-067047-induced hyperthermia was accompanied by increase in oxygen consumption (an index of thermogenesis), while chemical stimulation of TRPV4 increased tail heat loss, indicating that these two autonomic thermoeffectors in the rat are modulated through TRPV4 channels. Furthermore, rats chemically stimulated with TRPV4 agonist choose colder ambient temperatures and cold-seeking behaviour after thermal stimulation (28-31 degrees C) was inhibited by TRPV4 antagonist.ConclusionOur results suggest, for the first time, that TRPV4 channel is involved in the recruitment of behavioural and autonomic warmth-defence responses to regulate core body temperature.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP