Resonant nonstationary amplification of polychromatic laser pulses and conical emission in an optically dense ensemble of neon metastable atoms

Experimental and numerical investigation of single-beam and pump-probe interaction with a resonantly absorbing dense extended medium under strong and weak field-matter coupling is presented. Significant probe beam amplification and conical emission were observed. Under relatively weak pumping and high medium density, when the condition of strong coupling between field and resonant matter is fulfilled, the probe amplification spectrum has a form of spectral doublet. Stronger pumping leads to the appearance of a single peak of the probe beam amplification at the transition frequency. The greater probe intensity results in an asymmetrical transmission spectrum with amplification at the blue wing of the absorption line and attenuation at the red one. Under high medium density, a broad band of amplification appears. Theoretical model is based on the solution of the Maxwell-Bloch equations for a two-level system. Different types of probe transmission spectra obtained are attributed to complex dynamics of a coherent medium response to broadband polychromatic radiation of a multimode dye laser.Comment: 9 pages, 13 figures, corrected, Fig.8 was changed, to be published in Phys. Rev.

Adolescent growth and pubertal progression in the Silver-Russell syndrome.

The pattern of growth and development of 18 adolescent children with the Silver-Russell syndrome was studied. Mature height was about -3.6 standard deviation scores in both sexes. This is comparable to the height reduction at diagnosis, which has been reported previously. The pattern of puberty and adolescent growth was essentially normal and occurred at a marginally earlier time than normal, although in this small series the differences were not significant. In the girls there was a tendency to gain subcutaneous fat after puberty. This trend was not apparent in the boys

Crystal chemistry of a Mg-vesuvianite and implications of phase equilibria in the system CaO-MgO-Al 2 O 3 -SiO 2 -H 2 O-CO 2 1

Chemical analysis (including H 2 , F 2 , FeO, Fe 2 O 3 ) of a Mg-vesuvianite from Georgetown, Calif., USA, yields a formula, Ca 18.92 Mg 1.88 Fe 3+ 0.40 Al 10.97 Si 17.81- O 69.0.1 (OH) 8.84 F 0.14 , in good agreement on a cation basis with the analysis reported by Pabst (1936). X-ray and electron diffraction reveal sharp reflections violating the space group P4/nnc as consistent with domains having space groups P4/n and P4nc. Refinement of the average crystal structure in space group P4/nnc is consistent with occupancy of the A site with Al, of the half-occupied B site by 0.8 Mg and 0.2 Fe, of the half-occupied C site by Ca, of the Ca (1,2,3) sites by Ca, and the OH and O(10) sites by OH and O. We infer an idealized formula for Mg-vesuvianite to be Ca 19 Mg(MgAl 7 )Al 4 Si 18 O 69 (OH) 9 , which is related to Fe 3+- vesuvianite by the substitutions Mg + OH = Fe 3+ + O in the B and O(10) sites and Fe 3+ = Al in the AlFe site. Thermodynamic calculations using this formula for Mg-vesuvianite are consistent with the phase equilibria of Hochella, Liou, Keskinen & Kim (1982) but inconsistent with those of Olesch (1978). Further work is needed in determining the composition and entropy of synthetic vs natural vesuvianite before quantitative phase equilibria can be dependably generated. A qualitative analysis of reactions in the system CaO-MgO-Al 2 O 3 -SiO 2 -H 2 O-CO 2 shows that assemblages with Mg-vesuvianite are stable to high T in the absence of quartz and require water-rich conditions (XH 2 O > 0.8). In the presence of wollastonite, Mg-vesuvianite requires very water-rich conditions (XH 2 O > 0.97).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75453/1/j.1525-1314.1985.tb00311.x.pd