5,024 research outputs found

    High-power CW ultraviolet ion lasers

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    Over 1 watt of continuous ultraviolet output has been obtained from an argon ion laser in the 3500-3700Å range. This paper describes the discharge tube structure used and the operating characteristics of high-power ultraviolet laser transitions in argon and other noble gas ions. Operation at new wavelengths as well as CW operation of transitions previously observed only in pulsed operation are reported. Measurements of the dependence of spontaneous emission intensity from different ionization states on current and pressure are related to the excitation mechanisms for visible and uv ion lasers. The technique of population modulation by intracavity interruption has been used to study processes in the throat and uniform bore regions of ion laser discharges. The results of these studies are described. Problems encountered in the CW operation of ion laser discharge tubes at current densities above 1000Å/cm^2 are described

    Identification of proteins in the postsynaptic density fraction by mass spectrometry

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    Our understanding of the organization of postsynaptic signaling systems at excitatory synapses has been aided by the identification of proteins in the postsynaptic density (PSD) fraction, a subcellular fraction enriched in structures with the morphology of PSDs. In this study, we have completed the identification of most major proteins in the PSD fraction with the use of an analytical method based on mass spectrometry coupled with searching of the protein sequence databases. At least one protein in each of 26 prominent protein bands from the PSD fraction has now been identified. We found 7 proteins not previously known to be constituents of the PSD fraction and 24 that had previously been associated with the PSD by other methods. The newly identified proteins include the heavy chain of myosin-Va (dilute myosin), a motor protein thought to be involved in vesicle trafficking, and the mammalian homolog of the yeast septin protein cdc10, which is important for bud formation in yeast. Both myosin-Va and cdc10 are threefold to fivefold enriched in the PSD fraction over brain homogenates. Immunocytochemical localization of myosin-Va in cultured hippocampal neurons shows that it partially colocalizes with PSD-95 at synapses and is also diffusely localized in cell bodies, dendrites, and axons. Cdc10 has a punctate distribution in cell bodies and dendrites, with some of the puncta colocalizing with PSD-95. The results support a role for myosin-Va in transport of materials into spines and for septins in the formation or maintenance of spines

    Selective cooling of the brain in reindeer

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    Selective cooling of the brain during hyper-thermia has been demonstrated in several species of mammals (Baker 1979, 1982). Such cooling is achieved by heat exchange between the cooled venous blood returning from the nasal mucosa and the warmer arterial blood entering the brain via the carotid rete. Spot measurements of brain temperature (Tbr) and carotid blood temperature (TCar) were made within 1 min. of death in 40 wild reindeer (Rangifer tarandus tarandus). At Tear lower than 40.5°C Tbr was higher than T c a r. With increasing Tear above 40.5°C Tbr remained at approxima-tely 40.5°C, indicating that selective cooling of the brain had occurred

    Ancient Egypt 1916 Part 2

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    Part 2 of the 1916 Ancient Egypt books. Contents include the Gorringe collection, an early figure of Taurt, Egypt in the Grail Romance, and the queenly title, XXIInd dynasty.https://knowledge.e.southern.edu/kweeks_coll/1006/thumbnail.jp

    Carriage of an ACME II variant may have contributed to methicillin-resistant staphylococcus aureus sequence type 239-like strain replacement in Liverpool hospital, Sydney, Australia

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    Approximately 39% of methicillin-resistant Staphylococcus aureus (MRSA) sequence type 239 (ST239)-like bloodstream isolates from Liverpool Hospital (obtained between 1997 and 2008) carry an arginine catabolic mobile element (ACME). Whole-genome sequencing revealed that an ACME II variant is located between orfX and SCCmec III, and based on pulsed-field gel electrophoresis patterns and temporal relationships of all ST239-like isolates (n = 360), ACME carriage may have contributed to subpulsotype strain replacement

    Networks of gravitational wave detectors and three figures of merit

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    This paper develops a general framework for studying the effectiveness of networks of interferometric gravitational wave detectors and then uses it to show that enlarging the existing LIGO-VIRGO network with one or more planned or proposed detectors in Japan (LCGT), Australia, and India brings major benefits, including much larger detection rate increases than previously thought... I show that there is a universal probability distribution function (pdf) for detected SNR values, which implies that the most likely SNR value of the first detected event will be 1.26 times the search threshold. For binary systems, I also derive the universal pdf for detected values of the orbital inclination, taking into account the Malmquist bias; this implies that the number of gamma-ray bursts associated with detected binary coalescences should be 3.4 times larger than expected from just the beaming fraction of the gamma burst. Using network antenna patterns, I propose three figures of merit that characterize the relative performance of different networks... Adding {\em any} new site to the planned LIGO-VIRGO network can dramatically increase, by factors of 2 to 4, the detected event rate by allowing coherent data analysis to reduce the spurious instrumental coincident background. Moving one of the LIGO detectors to Australia additionally improves direction-finding by a factor of 4 or more. Adding LCGT to the original LIGO-VIRGO network not only improves direction-finding but will further increase the detection rate over the extra-site gain by factors of almost 2, partly by improving the network duty cycle... Enlarged advanced networks could look forward to detecting three to four hundred neutron star binary coalescences per year.Comment: 38 pages, 7 figures, 2 tables. Accepted for publication in Classical and Quantum Gravit

    Effects of delayed cord clamping on residual placental blood volume, hemoglobin and bilirubin levels in term infants: a randomized controlled trial

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    Objective: The objective of the study was to measure the effects of a 5-min delay (DCC) versus immediate cord clamping (ICC) on residual placental blood volume (RPBV) at birth, and hemoglobin and serum bilirubin at 24 to 48 h of age. Study Design: In this prospective randomized controlled trial, 73 women with term (37 to 41 weeks) singleton fetuses were randomized to DCC (5 min; n=37) or ICC (\u3c20 s; n=36). Results: Maternal and infant demographics were not different between the groups. Mean cord clamping time was 303±121 (DCC) versus 23±59 (ICC) s (P\u3c0.001) with 10 protocol violations. Cord milking was the proxy for DCC (n=11) when the provider could not wait. Infants randomized to DCC compared with ICC had significantly less RPBV (20.0 versus 30.8 ml kg−1, P\u3c0.001), higher hemoglobin levels (19.4 versus 17.8 g dl−1, P=0.002) at 24 to 48 h, with no difference in bilirubin levels. Conclusion: Term infants had early hematological advantage of DCC without increases in hyperbilirubinemia or symptomatic polycythemia

    The Bubbling Galactic Disk

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    A visual examination of the images from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) has revealed 322 partial and closed rings that we propose represent partially or fully enclosed three-dimensional bubbles. We argue that the bubbles are primarily formed by hot young stars in massive star formation regions. We have found an average of about 1.5 bubbles per square degree. About 25% of the bubbles coincide with known radio H II regions, and about 13% enclose known star clusters. It appears that B4-B9 stars (too cool to produce detectable radio H II regions) probably produce about three-quarters of the bubbles in our sample, and the remainder are produced by young O-B3 stars that produce detectable radio H II regions. Some of the bubbles may be the outer edges of H II regions where PAH spectral features are excited and may not be dynamically formed by stellar winds. Only three of the bubbles are identified as known SNRs. No bubbles coincide with known planetary nebulae or W-R stars in the GLIMPSE survey area. The bubbles are small. The distribution of angular diameters peaks between 1' and 3' with over 98% having angular diameters less than 10' and 88% less than 4'. Almost 90% have shell thicknesses between 0.2 and 0.4 of their outer radii. Bubble shell thickness increases approximately linearly with shell radius. The eccentricities are rather large, peaking between 0.6 and 0.7; about 65% have eccentricities between 0.55 and 0.85

    A burst search for gravitational waves from binary black holes

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    Compact binary coalescence (CBC) is one of the most promising sources of gravitational waves. These sources are usually searched for with matched filters which require accurate calculation of the GW waveforms and generation of large template banks. We present a complementary search technique based on algorithms used in un-modeled searches. Initially designed for detection of un-modeled bursts, which can span a very large set of waveform morphologies, the search algorithm presented here is constrained for targeted detection of the smaller subset of CBC signals. The constraint is based on the assumption of elliptical polarisation for signals received at the detector. We expect that the algorithm is sensitive to CBC signals in a wide range of masses, mass ratios, and spin parameters. In preparation for the analysis of data from the fifth LIGO-Virgo science run (S5), we performed preliminary studies of the algorithm on test data. We present the sensitivity of the search to different types of simulated CBC waveforms. Also, we discuss how to extend the results of the test run into a search over all of the current LIGO-Virgo data set.Comment: 12 pages, 4 figures, 2 tables, submitted for publication in CQG in the special issue for the conference proceedings of GWDAW13; corrected some typos, addressed some minor reviewer comments one section restructured and references updated and correcte
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