Studies on the respiratory modulation of sympathetic activity

Sympathetic activity is modulated by central respiratory drive. Studies using whole nerve recordings in the rat have demonstrated different patterns of respiratory modulation in various sympathetic nerves. These regional differences in the discharge patterns of sympathetic outflows may result from either varying proportions of sympathetic neurones with a particular respiratory-related discharge pattern contributing to each whole-nerve activity or sympathetic preganglionic neurones (SPNs) projecting into different nerves having characteristic respiratory modulations. The present study has investigated the respiratory-related discharge patterns of a group of SPNs projecting to the lumbar sympathetic chain (LSC). Furthermore, the hypothesis that caudal raphe nuclei (raphe obscurus, pallidus and magnus) convey central respiratory drive onto sympathetic outflow has been examined. In anaesthetized and vagotomized rats extracellular recordings were made from identified SPNs projecting to or through the lumbar sympathetic chain between L4 and L5 ganglia, and from caudal raphe neurones with axons projecting to the spinal cord. The respiratory-related firing patterns were analysed. Differences in patterns of respiratory modulation and the proportion of SPNs with a certain pattern of respiratory modulation were found between SPNs recorded in the present study and SPNs located in upper thoracic spinal segments reported previously. These findings provide an explanation of the regional differences of respiratory modulation in various sympathetic nerves. Many caudal raphe-spinal neurones with respiratory-related activity could be activated antidromically from the area of the intermediolateral cell column (IML) and activity in some of these neurons correlated to the 2 to 6 Hz rhythm of cervical sympathetic activity. The findings are consistent with the idea that caudal raphe neurones within the region from which I recorded in this study are part of a supraspinal network that contributes to the 2 to 6 Hz component of sympathetic nerve activity. Therefore some raphe-spinal neurones may relay both "respiratory" and "sympathetic" rhythmic components to the sympathetic outflow. These spinally- projecting neurones in caudal raphe nuclei are different from those in the rostral ventrolateral medulla (RVLM) as they have no baroreceptor-related activity. Additionally, they do not have the "typical" characteristics of 5-HT containing neurones which have slow conduction velocities, and slow regular firing characteristics: the majority had small myelinated axons as indicated by their conduction velocities and relatively high discharge rates and irregular firing characteristics

4-Methyl-7-[2-(1H-1,2,4-triazol-1-yl)eth­oxy]-2H-chromen-2-one

In the title mol­ecule, C14H13N3O3, the dihedral angle between the triazole ring and coumarin ring system is 73.01 (4)°. The crystal structure is stabilized by weak inter­molecular C—H⋯N and C—H⋯O hydrogen bonds

Parton shower algorithm with saturation effect

We extend the previously developed small $x$ parton shower algorithm to include the kinematic constraint effect and $k_t$ resummation effect. This work enables the Monte Carlo generator to simultaneously resum large $k_t$ and small $x$ logarithms in the saturation regime for the first time. It is an important step towards simulating processes involving multiple well separated hard scales, such as di-jet production in eA collisions at EIC.Comment: 12 pages, 4 figures. arXiv admin note: text overlap with arXiv:2211.0717

Accelerating Stochastic Sequential Quadratic Programming for Equality Constrained Optimization using Predictive Variance Reduction

In this paper, we propose a stochastic method for solving equality constrained optimization problems that utilizes predictive variance reduction. Specifically, we develop a method based on the sequential quadratic programming paradigm that employs variance reduction in the gradient approximations. Under reasonable assumptions, we prove that a measure of first-order stationarity evaluated at the iterates generated by our proposed algorithm converges to zero in expectation from arbitrary starting points, for both constant and adaptive step size strategies. Finally, we demonstrate the practical performance of our proposed algorithm on constrained binary classification problems that arise in machine learning.Comment: 41 pages, 5 figures, 4 table

Influence of wastewater composition on nutrient removal behaviors in the new anaerobic–anoxic/nitrifying/induced crystallization process

AbstractIn this study, the new anaerobic–anoxic/nitrifying/induced crystallization (A2N–IC) system was compared with anaerobic-anoxic/nitrifying (A2N) process to investigate nutrient removal performance under different influent COD and ammonia concentrations. Ammonia and COD removal rates were very stable in both processes, which were maintained at 84.9% and 86.6% when the influent ammonia varied from 30mgL−1 to 45mgL−1 and COD ranged from 250mgL−1 to 300mgL−1. The effluent phosphorus always maintained below 0.2mgL−1 in A2N–IC, whereas in A2N the effluent phosphorus concentration was 0.4–1.7mgL−1, demonstrating that A2N–IC is suitable to apply in a broader influent COD and ammonia concentration range. Under higher influent COD (300mgL−1) or lower ammonia conditions (30mgL−1), the main function of chemical induced crystallization was to coordinate better nutrient ratio for anoxic phosphorus uptake, whereas under high phosphorus concentration, it was to reduce phosphorus loading for biological system. Under the similar influent wastewater compositions, phosphorus release amounts were always lower in A2N–IC. To clarify the decrease procedure of phosphorus release in the A2N–IC, the equilibrium between chemical phosphorus removal and biological phosphorus removal in A2N–IC was analyzed by mass balance equations. During the long-term experiment, some undesirable phenomena were observed: the declining nitrification in post-aerobic tank and calcium phosphorus precipitation in the anaerobic tank. The reasons were analyzed; furthermore, the corresponding improvements were proposed. Nitrification effect could be enhanced in the post-aerobic tank, therefore ammonia removal rate could be increased; and biologically induced phosphorus precipitation could be inhibited by controlling pH at the anaerobic stage, so the phosphorus release and recovery could be improved