Quantum versus classical descriptions of sub-Poissonian light generation in three-wave mixing

Sub-Poissonian light generation in the non-degenerate three-wave mixing is studied numerically and analytically within quantum and classical approaches. Husimi Q-functions and their classical trajectory simulations are analysed to reveal a special regime corresponding to the time-stable sub-Poissonian photocount statistics of the sum-frequency mode. Conditions for observation of this regime are discussed. Theoretical predictions of the Fano factor and explanation of the extraordinary stabilization of the sub-Poissonian photocount behavior are obtained analytically by applying the classical trajectories. Scaling laws for the maximum sub-Poissonian behavior are found. Noise suppression levels in the non-degenerate vs degenerate three-wave mixing are discussed on different time scales compared to the revival times. It is shown that the non-degenerate conversion offers much better stabilization of the suppressed noise in comparison to that of degenerate process.Comment: 9 pages, 12 figures, to be published in J. Optics

Diffuse AIDS-related lymphoma

A 47-year-old woman was referred to the hospital with non-productive coughing, fever, fatigue, weight loss. She was known for a 3-year-long standing HIV infection. Blood tests showed an increased C-reactive protein (CRP: 3.6 mg/dl, nl < 1 mg/dl), an increased lactate deshydrogenase (LDH: 875 UI/L, nl < 248 UI/L) and an Epstein-Barr virus reactivation. A chest radiograph was performed (not shown), followed by a contrast-enhanced CT scan of the thorax (Fig. 1) and the abdomen (Fig. 2). Based on the CT scan examination, a pleural puncture was performed for cytological analysis (Fig. 3

5-HT inhibits N-type but not L-type Ca2+ channels via 5-HT1A receptors in lamprey spinal neurons

5-HT is a potent modulator of locomotor activity in vertebrates. In the lamprey, 5-HT dramatically slows fictive swimming. At the neuronal level it reduces the postspike slow afterhyperpolarization (sAHP), which is due to apamin-sensitive Ca2+-dependent K+ channels (K-Ca). Indirect evidence in early experiments suggested that the sAHP reduction results from a direct action of 5-HT on K-Ca channels rather than an effect on the Ca2+ entry during the action potential [Wallen et al., (1989) J. Neurophysiol., 61, 759-768]. In view of the characterization of different subtypes of Ca2+ channels with very different properties, we now reinvestigate if there is a selective action of 5-HT on a Ca2+ channel subtype in dissociated spinal neurons in culture. 5-HT reduced Ca2+ currents from high voltage activated channels. N-type, but not L-type, Ca2+ channel blockers abolished this 5-HT-induced reduction. It was also confirmed that 5-HT depresses Ca2+ currents in neurons, including motoneurons, in the intact spinal cord. 8-OH-DPAT, a 5-HT1A receptor agonist, also inhibited Ca2+ currents in dissociated neurons. After incubation in pertussis toxin, to block G(i/o) proteins, 5-HT did not reduce Ca2+ currents, further indicating that the effect is caused by an activation of 5-HT1A receptors. As N-type, but not L-type, Ca2+ channels are known to mediate the activation of K-Ca channels and presynaptic transmitter release at lamprey synapses, the effects of 5-HT reported here can contribute to a reduction in both actions

Microstructural and mechanical properties of 9%Ni steels used for the construction of LNG storage tanks

International audienc