Observations of time delayed all-optical routing in a slow light regime

We report an observation of a delayed all-optical routing/switching phenomenon based on ultraslow group velocity of light via nondegenerate four-wave mixing processes in a defected solid medium. Unlike previous demonstrations of enhanced four-wave mixing processes using the slow light effects, the present observation demonstrates a direct retrieval of the resonant Raman-pulse excited spin coherence into photon coherence through coherence conversion processes.Comment: 5 pages with 3 figures include

The Mass-Loss Return From Evolved Stars to The Large Magellanic Cloud VI: Luminosities and Mass-Loss Rates on Population Scales

We present results from the first application of the Grid of Red Supergiant and Asymptotic Giant Branch ModelS (GRAMS) model grid to the entire evolved stellar population of the Large Magellanic Cloud (LMC). GRAMS is a pre-computed grid of 80,843 radiative transfer (RT) models of evolved stars and circumstellar dust shells composed of either silicate or carbonaceous dust. We fit GRAMS models to ~30,000 Asymptotic Giant Branch (AGB) and Red Supergiant (RSG) stars in the LMC, using 12 bands of photometry from the optical to the mid-infrared. Our published dataset consists of thousands of evolved stars with individually determined evolutionary parameters such as luminosity and mass-loss rate. The GRAMS grid has a greater than 80% accuracy rate discriminating between Oxygen- and Carbon-rich chemistry. The global dust injection rate to the interstellar medium (ISM) of the LMC from RSGs and AGB stars is on the order of 1.5x10^(-5) solar masses/yr, equivalent to a total mass injection rate (including the gas) into the ISM of ~5x10^(-3) solar masses/yr. Carbon stars inject two and a half times as much dust into the ISM as do O-rich AGB stars, but the same amount of mass. We determine a bolometric correction factor for C-rich AGB stars in the K band as a function of J - K color, BC(K) = -0.40(J-K)^2 + 1.83(J-K) + 1.29. We determine several IR color proxies for the dust mass-loss rate (MLR) from C-rich AGB stars, such as log (MLR) = (-18.90)/((K-[8.0])+3.37)-5.93. We find that a larger fraction of AGB stars exhibiting the `long-secondary period' phenomenon are O-rich than stars dominated by radial pulsations, and AGB stars without detectable mass-loss do not appear on either the first-overtone or fundamental-mode pulsation sequences.Comment: 19 pages, 19 figure

Effect of disorder on transport properties in a tight-binding model for lead halide perovskites

The hybrid organic-inorganic lead halide perovskite materials have emerged as remarkable materials for photovoltaic applications. Their strengths include good electric transport properties in spite of the disorder inherent in them. Motivated by this observation, we analyze the effects of disorder on the energy eigenstates of a tight-binding model of these materials. In particular, we analyze the spatial extension of the energy eigenstates, which is quantified by the inverse participation ratio. This parameter exhibits a tendency, and possibly a phase transition, to localization as the on-site energy disorder strength is increased. However, we argue that the disorder in the lead halide perovskites corresponds to a point in the regime of highly delocalized states. Our results also suggest that the electronic states of mixed-halide materials tend to be more localized than those of pure materials, which suggests a weaker tendency to form extended bonding states in the mixed-halide materials and is therefore not favourable for halide mixing.Comment: 24 pages (preprint), 11 figure

The morphology of the cellular constituents of the blood of Salmo trutta

Thesis (M.A.)--Boston UniversityThe morphology of the cellular constituents of the blood of Salmo trutta was investigated. Blood cell counts and differential counts were included. Cellular elements of the blood were found to be nucleated erythrocytes, lymphocytes, neutrophils, monocytes and thrombocytes. Dried smears of blood which had been stained with Wright's stain indicated the erythrocytes were flat elliptical cells . However, the phase microscope revealed the biconcave shape of the mature erythrocyte, the concavity being interrupted by the central nucleus. Average cell rreasurements were 16.5 microns in length and 10.2 microns in width. [TRUNCATED

An analysis of the peculiar A star HD 204411

Spectrum analysis of cool Ap star HD 20441

The Lyman-alpha Forest at z~4: Keck HIRES Observations of Q 0000-26

This paper describes a study of the Lyman-alpha forest absorption clouds along the quasar sightline Q0000-26 (zem=4.1). The spectrum was obtained with the High Resolution Spectrometer on the 10m Keck telescope. We derive accurate H I column density and Doppler width distributions for the clouds from Voigt profile fitting. We also analyze simulated Lyman-alpha forest spectra of matching characteristics in order to gauge the effects of line blending/blanketing and noise in the data. The results are compared with similar studies at lower redshifts in order to study any possible evolution in the clouds' properties. We also estimate the mean intensity of the UV background at z=4 from an analysis of the proximity effect.Comment: plain TeX containing 23 PS pages, 3 PS tables, and 9 PS figures, ApJ, Dec 1, 1996 issue replacing an earlier version which contains an corrupted table

CO J = 2 - 1 Emission from Evolved Stars in the Galactic Bulge

We observe a sample of 8 evolved stars in the Galactic Bulge in the CO J = 2 - 1 line using the Submillimeter Array (SMA) with angular resolution of 1 - 4 arcseconds. These stars have been detected previously at infrared wavelengths, and several of them have OH maser emission. We detect CO J = 2 - 1 emission from three of the sources in the sample: OH 359.943 +0.260, [SLO2003] A12, and [SLO2003] A51. We do not detect the remaining 5 stars in the sample because of heavy contamination from the galactic foreground CO emission. Combining CO data with observations at infrared wavelengths constraining dust mass loss from these stars, we determine the gas-to-dust ratios of the Galactic Bulge stars for which CO emission is detected. For OH 359.943 +0.260, we determine a gas mass-loss rate of 7.9 (+/- 2.2) x 10^-5 M_Sun/year and a gas-to-dust ratio of 310 (+/- 89). For [SLO2003] A12, we find a gas mass-loss rate of 5.4 (+/- 2.8) x 10^-5 M_Sun/year and a gas-to-dust ratio of 220 (+/- 110). For [SLO2003] A51, we find a gas mass-loss rate of 3.4 (+/- 3.0) x 10^-5 M_Sun/year and a gas-to-dust ratio of 160 (+/- 140), reflecting the low quality of our tentative detection of the CO J = 2 - 1 emission from A51. We find the CO J = 2 - 1 detections of OH/IR stars in the Galactic Bulge require lower average CO J = 2 - 1 backgrounds.Comment: 40 pages, 16 figures, appeared in the 1 March 2013 issue of the Astrophysical Journa

Letter from C. S. Sargent to John Muir, 1894 Jan 8.

ARNOLD ARBORETUM,HARVARD UNIVERSITY.Jamaica Plain Mass., January 8, 1894My dear Mr. Muir:Thank you. The Silva is coming on slowly. The fifth volume appeared in October and the sixth is fairly on the way. I am working hard at it in order to get it off my hands in time to pay you a visit this spring. I should have accomplished this easily if the grip had not got the best of me in December and caused me to lose nearly a month\u27s time. However, I still want to get away, if I can, in time to see something of the Spring vegetation of California which will be quite new to me.Planned it [illegible] a dozen years [illegible] - 1893When we meet we can talk over that trip to India which I am still keen for, and all the more so if I can have the pleasure of your company.We often think and speak of your visit to Brookline and I hope the time is not far distant when you will come and see us again. I am glad you had such a good time on the other side of the ocean.With kind regards,I am,always faithfully yours,C. S. Sargent.John Muir, Esq.,Martinez, Cal.0176