Functional Review and Macrostructure of the Caecum in Ardeidae

Situated on the lower digestive tract, caeca typically project cranially from the juncture of the small and large intestine. Recent studies have proposed that the role of caeca in the avian system is to act as fermentation chambers to synthesize vitamins, modulate gut microflora, and absorb nutrients; however, functionality differs with diet. Caeca are a typical characteristic of the avian gastrointestinal tract, with varying sizes and shapes, or even rudimentary or absent in some species. Caeca are notably singular and relatively small in Ardeids. Morphometric consistency in the number and presence of caeca on the lower intestinal tract of Ardeids was determined on a sample of 70 birds obtained from South Florida wildlife rehabilitation centers. This study also reports the findings of caeca length relative to morphometric and intestinal measurements. Caecum length relative to tarsus length was found to be significantly different between Cattle Egrets and Green Herons along with Green Herons and Great White Herons. Caecum length relative to small intestine length was significantly different between Great Egrets and Cattle Egrets. In order to further the understanding of Ardeid caeca, next steps include further research into the function of caeca in piscivorous birds and an in-depth look at the bacteria found in the avian caecum. In particular, future studies can be aimed at understanding why Green Herons differ so greatly from other Ardeids

Polarized micro-Raman studies of femtosecond laser written stress-induced optical waveguides in diamond

Understanding the physical mechanisms of the refractive index modulation induced by femtosecond laser writing is crucial for tailoring the properties of the resulting optical waveguides. In this work we apply polarized Raman spectroscopy to study the origin of stress-induced waveguides in diamond, produced by femtosecond laser writing. The change in the refractive index induced by the femtosecond laser in the crystal is derived from the measured stress in the waveguides. The results help to explain the waveguide polarization sensitive guiding mechanism, as well as providing a technique for their optimization.Comment: 5 pages, 4 figure

Integral cross sections for electron scattering by ground state Ba atoms

We have used the convergent close-coupling method and a unitarized first-order many-body theory to calculate integral cross sections for elastic scattering and momentum transfer, for excitation of the 5d^2 ^1S, 6s6p^1P_1, 6s7p^1P_1, 6s8p^1P_1, 6s5d^1D_2, 5d^2^1D_2, 6s6d^1D_2, 6p5d^1F_3, 6s4f^1F_3, 6p5d^1D_2, 6s6p^3P_{0,1,2}, 6s5d^3D_{1,2,3}, and 6p5d^3D_2 states, for ionization and for total scattering by electron impact on the ground state of barium at incident electron energies from 1 to 1000 eV. These results and all available experimental data have been combined to produce a recommended set of integral cross sections.Comment: 47 pages, 8 tables, 25 figure

Solid-state laser system for laser cooling of Sodium

We demonstrate a frequency-stabilized, all-solid laser source at 589 nm with up to 800 mW output power. The laser relies on sum-frequency generation from two laser sources at 1064 nm and 1319 nm through a PPKTP crystal in a doubly-resonant cavity. We obtain conversion efficiency as high as 2 W/W^2 after optimization of the cavity parameters. The output wavelength is tunable over 60 GHz, which is sufficient to lock on the Sodium D2 line. The robustness, beam quality, spectral narrowness and tunability of our source make it an alternative to dye lasers for atomic physics experiments with Sodium atoms

Performance extension of Raman lasers using synthetic diamond

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Wavelength selectable solid-state Raman lasers in the visible and ultraviolet ranges

Solid-state Raman lasers are known as important sources at normally difficult to access wavelengths, and our recent studies have shown that they also form the basis of a class of wavelength selectable lasers. This paper summarizes our recent studies in wavelength selectable Raman lasers in the visible (532-650nm) and ultraviolet (266-321 nm).9 page(s

Characteristics of emergent nano-structures formed on diamond by two-photon UV etching

Diamond surfaces etched in the UV at sub-ablation fluencies develop deep sub-wavelength nanostructures with morphology dependent on the incident polarization. Characterization of the development of etched patterns provides evidence for bond-selective scission and ejection of carbon species.2 page(s

Diamond Raman lasers : nonlinear optical beam conversion at high average powers

Recent advances in high power beam conversion in diamond are reviewed. It is shown that there are excellent prospects for developing high power (kilowatt) devices with diffraction-limited beam quality in bulk and at room temperature.2 page(s