Background The quest to quantify myocardial perfusion has been largely motivated by the desire to obtain quantitative, observer-independent, and reproducible measures of myocardial perfusion. Spiral pulse sequences have multiple advantages for myocardial perfusion imaging including high acquisition efficiency, high signal to noise (SNR) and robustness to motion. We have developed a spiral pulse...

Previous studies have shown significant differences in the enhancement of star-formation rate (SFR) and efficiency (SFE=SFR/M_mol) between spiral-spiral spiral-elliptical mergers. In order to shed light on physical mechanism these differences, we present NOEMA observations molecular gas distribution kinematics (linear resolutions ~ 2kpc) two representative close major-merger star-forming pairs:...

We show that trajectories of the ABC flow in the near-integrable regime are typically of two distinct types: spiral waves and edge transport orbits. We prove existence of special helical orbits (spiral waves), which belong to the Kolmogorov-Arnold-Moser (KAM) regime, by using the contraction mapping principle in the Hamiltonian formulation. In the non-integrable regime we also find and analyze ...

Chemotactic cell motion in aggregation patterns of the slime mould Dictyostelium discoideum is analyzed by a computerized cross-correlation method. In this excitable medium the movement of amoebae is selforganized by signals of cAMP that propagate as rotating spirals or expanding concentric circles (target patterns). A vortex-like rotation of cells is found close to the core of spiral waves, wi...

An extensible semiflexible filament moving on a motility assay of motor proteins undergoes first order re-entrant phase transition from open chain to spiral as function the extension rate and turnover proteins.

On the circular curve, lateral acceleration affects comfort. On the spiral, both lateral acceleration and jerk affect comfort.  The determination of maximum curving speed on the basis of lateral acceleration only is not critical because the lateral acceleration is proportional to the square of speed whereas jerk is proportional to cubic power of speed. The maximum speed on a curve is thus signi...