THE PHYSIOLOGICAL RESPONSE OF THE CIRCULATORY SYSTEM TO EXPERIMENTAL ALTERATIONS : II. THE EFFECT OF VARIATIONS IN TOTAL BLOOD VOLUME.

The pericardium presents a limiting or constricting action to acute dilatation of the heart. The diastolic pressure tends to approach the systolic pressure in a circulatory system distended with blood. The limiting action of the pericardium may be responsible for the small differences in the size of the heart noted by Meek and Eyster in their studies on the effect of plethora. The views concerning the function of the pericardium are divergent. That it may restrict the heart in cases of acute dilatation is shown in the above experiments. If the tension upon the pericardium be exerted over a prolonged period of time, as occurs in cases of pericardial effusion, the pericardium readily enlarges. If, however, the intrapericardial pressure should at any time equal the pressure in the venæ cavæ, blood would no longer enter the heart and the condition would become fatal. In recovery experiments, pericardiectomy was followed by no demonstrable effect upon the general health of the dog, upon the response to exercise, or upon the size of the heart (6)

On the effect of charge self-consistency in DFT+DMFT calculations for complex transition metal oxides

We investigate the effect of charge self-consistency (CSC) in density functional theory plus dynamical mean-field theory (DFT+DMFT) calculations compared to simpler "one-shot" calculations for materials where interaction effects lead to a strong redistribution of electronic charges between different orbitals or between different sites. We focus on two systems close to a metal-insulator transition, for which the importance of CSC is currently not well understood. Specifically, we analyze the strain-related orbital polarization in the correlated metal CaVO$_3$ and the spontaneous electronic charge disproportionation in the rare-earth nickelate LuNiO$_3$. In both cases, we find that the CSC treatment reduces the charge redistribution compared to cheaper one-shot calculations. However, while the MIT in CaVO$_3$ is only slightly shifted due to the reduced orbital polarization, the effect of the site polarization on the MIT in LuNiO$_3$ is more subtle. Furthermore, we highlight the role of the double-counting correction in CSC calculations containing different inequivalent sites.Comment: 11 pages, 6 figure

Acid and non-acid gastro-esophageal refluxes in children with chronic pulmonary diseases

SummaryObjectivesAcid gastro-esophageal reflux has been shown associated with chronic pulmonary diseases. The role of non-acid refluxes in these children is still unknown. Therefore we investigated the prevalence of acid and non-acid refluxes, and their association with desaturations, in children with chronic pulmonary symptoms.MethodsIn 25 children aged 6 months to 15 years with unexplained chronic cough, wheeze or sputum production, refluxes were assessed by 24h-multiple intra-esophageal impedance measurements, simultaneous pH metry and continuous recording of oxygen saturation.ResultspH in the proximal and distal esophagus as well as six impedance channels were evaluated in all subjects. A mean of 129.4 refluxes per day per patient was detected. Complete and technically usable readings of oxygen saturation were obtained in 14 children. In this group the subjects had a mean of 112.6 refluxes and 92.6 desaturations per day per patient. The symptom index and symptom sensitivity index for acid refluxes were 34.7% and 24.6%, respectively, for non-acid refluxes 3.0% and 66.7%, respectively.ConclusionsWe found a high prevalence of acid reflux and a very low number of non-acid refluxes in this population. The symptom index was negative for all types of reflux, whereas the symptom sensitivity index was positive for both acid and non-acid reflux. Our data support a relation between acid gastro-esophageal refluxes and chronic pulmonary symptoms; however, this study does not support a role of non-acid reflux in children with respiratory symptoms, which are not on antacid medication

Training biases in machine learning for the analytic continuation of quantum many-body Green's functions

We address the problem of analytic continuation of imaginary-frequency Green's functions, which is crucial in many-body physics, using machine learning based on a multi-level residual neural network. We specifically address potential biases that can be introduced due to the use of artificially created spectral functions that are employed to train the neural network. We also implement an uncertainty estimation of the predicted spectral function, based on Monte Carlo dropout, which allows to identify frequency regions where the prediction might not be accurate, and we study the effect of noise, in particular also for situations where the noise level during training is different from that in the actual data. Our analysis demonstrates that this method can indeed achieve a high quality of prediction, comparable or better than the widely used maximum entropy method, but that further improvement is currently limited by the lack of true data that can be used for training. We also benchmark our approach by applying it to the case of SrVO$_3$, where an accurate spectral function has been obtained from dynamical mean-field theory using a solver that works directly on the real frequency axis

Exciton Condensation Driving the Periodic Lattice Distortion of 1T-TiSe₂

We address the lattice deformation of 1T-TiSe₂ within the exciton condensate phase. We show that, at low temperature, condensed excitons influence the lattice through electron-phonon interaction. It is found that at zero temperature, in the exciton condensate phase of 1T-TiSe₂, this exciton condensate exerts a force on the lattice generating ionic displacements comparable in amplitude to what is measured in experiment. This is thus the first quantitative estimation of the amplitude of the periodic lattice distortion observed in 1T-TiSe₂ as a consequence of the exciton condensate phase

Impact of electron-hole correlations on the 1T-TiSe21T\text{-}{\mathrm{TiSe}}_{2} electronic structure

Several experiments have been performed on 1T−TiSe2 in order to identify whether the electronic structure is semimetallic or semiconducting without reaching a consensus. In this Letter, we theoretically study the impact of electron-hole and electron-phonon correlations on the bare semimetallic and semiconducting electronic structure. The resulting electron spectral functions provide a direct comparison of both cases and demonstrate that 1T−TiSe2 is of predominant semiconducting character with some spectral weight crossing the Fermi level

Charge self-consistent electronic structure calculations with dynamical mean-field theory using Quantum ESPRESSO, Wannier90 and TRIQS

We present a fully charge self-consistent implementation of dynamical mean field theory (DMFT) combined with density functional theory (DFT) for electronic structure calculations of materials with strong electronic correlations. The implementation uses the Quantum ESPRESSO package for the density functional theory calculations, the Wannier90 code for the up-/downfolding and the TRIQS software package for setting up and solving the DMFT equations. All components are available under open source licenses, are MPI-parallelized, fully integrated in the respective packages, and use an hdf5 archive interface to eliminate file parsing. We show benchmarks for three different systems that demonstrate excellent agreement with existing DFT+DMFT implementations in other ab-initio electronic structure codes.Comment: 13 pages, 11 figure