This study evaluates the capability of atmospheric CO column measurements under cloudy conditions using an airborne intensity-modulated continuous-wave integrated-path-differential-absorption lidar operating in the 1.57-μm CO absorption band. The atmospheric CO column amounts from the aircraft to the tops of optically thick cumulus clouds and to the surface in the presence of optically thin clouds are retrieved from lidar data obtained during the summer 2011 and spring 2013 flight campaigns, respectively.
View Article and Find Full Text PDFA new modulation technique for Continuous Wave (CW) Lidar is presented based on Binary Phase Shift Keying (BPSK) using orthogonal carriers closely spaced in frequency, modulated by Maximum Length (ML) sequences, which have a theoretical autocorrelation function with no sidelobes. This makes it possible to conduct multi-channel atmospheric differential absorption measurements in the presence of thin clouds without the need for further processing to remove errors caused by sidelobe interference while sharing the same modulation bandwidth. Flight tests were performed and data were collected using both BPSK and linear swept frequency modulation.
View Article and Find Full Text PDFAn interpolation method is described for range measurements of high precision altimetry with repeating intensity modulated continuous wave (IM-CW) lidar waveforms using binary phase shift keying (BPSK), where the range profile is determined by means of a cross-correlation between the digital form of the transmitted signal and the digitized return signal collected by the lidar receiver. This method uses reordering of the array elements in the frequency domain to convert a repeating synthetic pulse signal to single highly interpolated pulse. This is then enhanced further using Richardson-Lucy deconvolution to greatly enhance the resolution of the pulse.
View Article and Find Full Text PDFAn interpolation method is described for range measurements of high precision and altimetry using repeating intensity-modulated continuous wave (IM-CW) lidar waveforms, where the range is determined by means of a cross-correlation between the digital form of the transmitted signal and the digitized return signal collected by the lidar receiver. This method uses reordering of the array elements in the frequency domain to convert a repeating synthetic pulse signal to single highly interpolated pulse. The computation of this processing is marginally greater than the correlation itself, as it only involves reordering of the correlation in the frequency domain, which makes it possible to implement this in a real time application.
View Article and Find Full Text PDFThe 2007 National Research Council (NRC) Decadal Survey on Earth Science and Applications from Space recommended Active Sensing of CO(2) Emissions over Nights, Days, and Seasons (ASCENDS) as a midterm, Tier II, NASA space mission. ITT Exelis, formerly ITT Corp., and NASA Langley Research Center have been working together since 2004 to develop and demonstrate a prototype laser absorption spectrometer for making high-precision, column CO(2) mixing ratio measurements needed for the ASCENDS mission.
View Article and Find Full Text PDFVernalized gemmules of the marine sponge Haliclona loosanoffi were cultured at 20°C, fixed at 24-hour intervals (0-11 days), and processed for light microscopy by using a variety of absorption and fluorescent staining methods. The cytochemistry and morphology of development were compared to the well-studied developmental patterns of freshwater sponges and to the patterns described in the marine sponge Suberites domuncula. The precocious development of H.
View Article and Find Full Text PDFDissection and a variety of absorption and fluorescent cytochemical methods have demonstrated that Antrodiaetus unicolor females have only one type of silk gland and spigot and, consequently, the simplest silk production system of any spider yet investigated histochemically. The small spherical to pear-shaped glands are grouped into four clusters, each cluster serving one of the four spinnerets. The spigots are long, slender, and slightly bent distally.
View Article and Find Full Text PDFActa Embryol Morphol Exp (Halocynthia Assoc)
January 1983
The spongillid freshwater sponges asexually produce an encapsulated dormant stage, the gemmule. With release from dormancy, internal, yolk-laden, binucleate thesocytes differentiate into histoblasts or archeocytes. The histoblasts emerging first from the gemmule form the initial pinacoderm of the hatching sponge.
View Article and Find Full Text PDFHistochemistry
November 1976
Dansylhydrazine, previously introduced in a selective fluorescent cytochemical method for the demonstration of sialic acid residues of cellular glycoconjungates, may be broadly applied as a specific, covalently bonded fluorochrome of aldehyde residues, both those naturally occurring as in elastin or those generated through PAS or Feulgen-type procedures.
View Article and Find Full Text PDFUltrastructure and shell formation in the testaceous ameba, Lesquereusia spiralis, were investigated with both scanning and transmission electron microscopy and X-ray microanalysis. The nucleus, surrounded by a fibrous lamina, contains multiple nucleoli. The cytoplasm, containing a well developed granular endoplasmic reticulum, also contains remnants of starch granules in stages of digestion.
View Article and Find Full Text PDFA new method for the fluorescent staining of stalic acid-containing glycoconjugates in fixed tissues is described. The procedure uses mild periodate oxidation, followed by condensation with dansylhydrazine and reduction of the hydrazones to hydrazines. The specificity of the reaction for sialic acid is tested on model glycoconjugates.
View Article and Find Full Text PDFMicrospectrophotometric measurements of nuclei of adult choanocytes and archeocytes and larval archeocytes and flagellated ectodermal epithelia from stages III and IV were undertaken on tissues from the freshwater sponge, Eunapius fragilis (Leidy). The condensed nuclei of differentiated choanocytes and state IV flagellated epithelial cells presented integrated extinction values about 64% of those obtained for either adult or larval archeocytes. This suggests that such measurements represent sensitive indicators of deoxyribonucleoprotein-complex organization; thus, nuclear differentiation.
View Article and Find Full Text PDFFreshwater sponges, Corvomeyenia carolinensis Harrison, were placed into tap water to induce degenerative reduction body formation. Reduction bodies were examined using light and electron microscopy in order to define their histochemical and ultrastructural characteristics. The reduction body of freshwater sponges is an extremely simple developmental system consisting primarily of an archeocyte reserve delimited by a simple squamous pinacoderm.
View Article and Find Full Text PDFFreshwater sponges of the family Spongillidae reproduce sexually through formation of a parenchymula larva. The cytochemical characteristics of parenchymula larval metamorphosis - beginning with the blastula and terminating with the motile escape stage - for the spongillid Eunapius fragilis (Leidy) have been defined using both absorption and fluorescent cytochemical methods, particularly those demonstrating protein end-groups. Morphogenesis of the parenchymula larva of E.
View Article and Find Full Text PDFHistochemical preparations stained by a variant of the Morel-Sisley reaction for protein tyrosine were found to produce a red fluorescence when excited by broadband blue light which is topologically identical to the distribution of chromophore when viewed by absorption (equal transmission) microscopy. The fluorescence mode of viewing preparations stained by this method gave greater sensitivity and contrast than the absorption mode. The p-dimethylaminobenzaldehyde (DMAB)-nitrate method for protein tryptophan did not result in a useful fluorescent end-group method.
View Article and Find Full Text PDFFluorescent cytochemical techniques, chiefly end-group methods, have been employed in the characterization of cells in calid and algid normal and LUCKE tumor-bearing kidneys of the leopard frog, Rana pipiens. Cytoplasmic RNA and glycogen distribution reflect the known patterns of general metabolic activity of the respective cells in question. Protein sulfhydryl distribution is similar in normal distal tubules and tumors while both differ significantly from proximal tubules.
View Article and Find Full Text PDFThe cytology of the testaceous ameba, Lesquereusia spiralis (EHRENBERG) PENARD, has been described using a broad spectrum of cytochemical methods. Most cytological characteristics lie within the range of variability reported for free living non-shelled amebas. The shell of L.
View Article and Find Full Text PDFHistochemistry
October 1975
The hydroxy-naphthoic acid hydrazide (HNAH) procedure can be employed not only for selective fluorochroming of side chain carboxyl groups of proteins, but also for demonstration of certain exoplasmic structures---particularly basement membranes. The demonstration of basement membranes by the HNAH procedure is likely related to the relatively high levels of available side chain carboxyl groups in the noncollagen glycoproteins of basement membranes.
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