Quantum speed limit for noisy dynamics

The laws of quantum physics place a limit on the speed of computation, in particular the evolution time of a system cannot be arbitrarily fast. Bounds on the speed of evolution for unitary dynamics have been long studied. A few bounds on the speed of evolution for noisy dynamics have also been obtained recently, these bounds, however, are in general not tight. In this article we present a new framework for quantum speed limit of noisy dynamics. With this framework we obtain the exact maximal angle that a noisy dynamics can achieve at any given time, this then provides tight bounds on the evolution time for noisy dynamics. The obtained bound reveals that noisy dynamics are generically different from unitary dynamics, in particular we show that the 'orthogonalization' time, which is the minimum time needed to evolve any state to its orthogonal states, is in general not applicable to noisy dynamics.Comment: 6 pages. Comments are welcom

An unstructured-grid based volume-of-fluid method for extreme wave and freely-floating structure interactions

A Volume of Fluid (VOF) technique has been further developed and coupled with an incompressible Euler/Navier Stokes solver operating on adaptive, unstructured grids to simulate the interactions of extreme waves and a LNG carrier with full or partially filled tanks. The present implementation follows the classic VOF implementation for the liquid-gas system, considering only the liquid phase. Extrapolation algorithms are used to obtain velocities and pressures in the gas region near the free surface. An arbitrary Lagrangian-Eulerian (ALE) frame of reference is used. The mesh is moved in such a way as to minimize the distortion of the mesh due to body movement. The incompressible Euler/Navier-Stokes equations are solved using projection schemes and a finite element method on unstructured grids, and the free surface is captured by the VOF method. The computer code developed based on the method described above is used in this study to simulate a numerical seakeeping tank, where the waves are generated by the sinusoidal excitation of a piston paddle, and a freely-floating LNG carrier with full or partially filled tanks moves in response to the waves. Both head sea and oblique sea are considered in the simulation. Highly nonlinear wave-body interactions, such as green water on deck and sloshing, have been modeled successfully

An unstructured-grid based volume-of-fluid method for extreme wave and freely-floating structure interactions

A Volume of Fluid (VOF) technique has been further developed and coupled with an incompressible Euler/Navier Stokes solver operating on adaptive, unstructured grids to simulate the interactions of extreme waves and a LNG carrier with full or partially filled tanks. The present implementation follows the classic VOF implementation for the liquid-gas system, considering only the liquid phase. Extrapolation algorithms are used to obtain velocities and pressures in the gas region near the free surface. An arbitrary Lagrangian-Eulerian (ALE) frame of reference is used. The mesh is moved in such a way as to minimize the distortion of the mesh due to body movement. The incompressible Euler/Navier-Stokes equations are solved using projection schemes and a finite element method on unstructured grids, and the free surface is captured by the VOF method. The computer code developed based on the method described above is used in this study to simulate a numerical seakeeping tank, where the waves are generated by the sinusoidal excitation of a piston paddle, and a freely-floating LNG carrier with full or partially filled tanks moves in response to the waves. Both head sea and oblique sea are considered in the simulation. Highly nonlinear wave-body interactions, such as green water on deck and sloshing, have been modeled successfully

Effects of Sulfur Amino Acids on Tyrosyl or Serine/Threonine Phosphorylation and Translocation of Cytosolic Compounds to Cell Membrane in Stimulus-treated Human Neutrophils

We investigated the effects of various sulfur amino acids on the phosphorylation of proteins and the translocation of cytosolic compounds to cell membrane in stimulus-treated human neutrophils using specific monoclonal antibodies. D,L-homocysteine and D,L-homocysteine-thiolactone enhanced fMLP-induced tyrosyl phosphorylation of proteins and the translocation of p47phox, p67phox, and rac to the cell membrane in a concentration-dependent manner. L-cystathionine, NAc-L-cysteine and carboxymethylcysteine suppressed the tyrosyl phophorylation and translocation of cytosolic compounds to the cell membrane. L-cystathionine, L-cysteine and NAc-L-cysteine suppressed PMA-induced serine/threonine phosphorylation and the translocation of cytosolic compounds to the cell membrane. L-cysteine, NAc-L-cysteine and D,L-homocysteine enhanced AA-induced serine/threonine phosphorylation and the translocation of cytosolic compounds to the cell membrane, but L-cystathionine had opposite effects. These results indicated that the effects of sulfur amino acids on tyrosyl or serine/threonine phosphorylation and the translocation of p47phox, p67phox, and rac to the cell membrane in the stimulus-treated human neutrophils were in parallel with those of the stimulus-induced superoxide generation reported in previous paper. L-cysteine, D,L-homocysteine and L-cystathionine weakly inhibited lipid peroxidation, but the other sulfur amino acids tested had no effect.</p

Static and dynamical properties of the spin-5/2 nearly ideal triangular lattice antiferromagnet Ba3MnSb2O9

We study the ground state and spin excitation in Ba3MnSb2O9, an easy-plane S = 5/2 triangular lattice antiferromagnet. By combining single-crystal neutron scattering, electric spin resonance (ESR), and spin wave calculations, we determine the frustrated quasi-two-dimensional spin Hamiltonian parameters describing the material. While the material has a slight monoclinic structural distortion, which could allow for isosceles triangular exchanges and biaxial anisotropy by symmetry, we observe no deviation from the behavior expected for spin waves in the in-plane 120o state. Even the easy-plane anisotropy is so small that it can only be detected by ESR in our study. In conjunction with the quasi-two-dimensionality, our study establishes that Ba3MnSb2O9 is a nearly ideal triangular lattice antiferromagnet with the quasi-classical spin S = 5/2, which suggests that it has the potential for an experimental study of Z- or Z2-vortex excitations

Mapping 123 million neonatal, infant and child deaths between 2000 and 2017

Since 2000, many countries have achieved considerable success in improving child survival, but localized progress remains unclear. To inform efforts towards United Nations Sustainable Development Goal 3.2—to end preventable child deaths by 2030—we need consistently estimated data at the subnational level regarding child mortality rates and trends. Here we quantified, for the period 2000–2017, the subnational variation in mortality rates and number of deaths of neonates, infants and children under 5 years of age within 99 low- and middle-income countries using a geostatistical survival model. We estimated that 32% of children under 5 in these countries lived in districts that had attained rates of 25 or fewer child deaths per 1,000 live births by 2017, and that 58% of child deaths between 2000 and 2017 in these countries could have been averted in the absence of geographical inequality. This study enables the identification of high-mortality clusters, patterns of progress and geographical inequalities to inform appropriate investments and implementations that will help to improve the health of all populations