2,122 research outputs found

    Demonstration of a state-insensitive, compensated nanofiber trap

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    We report the experimental realization of an optical trap that localizes single Cs atoms ≃ 215 nm from surface of a dielectric nanober. By operating at magic wavelengths for pairs of counterpropagating red- and blue-detuned trapping beams, dierential scalar light shifts are eliminated, and vector shifts are suppressed by ≈ 250. We thereby measure an absorption linewidth Γ/2π = 5.7 ± 0.1 MHz for the Cs 6S_(1/2), F = 4 → 6P_(3/2), F' = 5 transition, where Γ_0/2π = 5.2 MHz in free space. Optical depth d ≃ 66 is observed, corresponding to an optical depth per atom d_1 ≃ 0.08. These advances provide an important capability for the implementation of functional quantum optical networks and precision atomic spectroscopy near dielectric surfaces

    Cystic fibrosis mice carrying the missense mutation G551D replicate human genotype phenotype correlations

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    We have generated a mouse carrying the human G551D mutation in the cystic fibrosis transmembrane conductance regulator gene (CFTR) by a one-step gene targeting procedure. These mutant mice show cystic fibrosis pathology but have a reduced risk of fatal intestinal blockage compared with 'null' mutants, in keeping with the reduced incidence of meconium ileus in G551D patients. The G551D mutant mice show greatly reduced CFTR-related chloride transport, displaying activity intermediate between that of cftr(mlUNC) replacement ('null') and cftr(mlHGU) insertional (residual activity) mutants and equivalent to approximately 4% of wild-type CFTR activity. The long-term survival of these animals should provide an excellent model with which to study cystic fibrosis, and they illustrate the value of mouse models carrying relevant mutations for examining genotype-phenotype correlations

    G92-1068 Planting and Harvesting Information for Nebraska Crops

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    This NebGuide gives information on the normal practices of planting and harvesting crops grown in Nebraska. This publication is a guide for some basic crop management practices for a variety of Nebraska crops. There are many special or unique cropping situations that will require some adjustments to these suggestions

    G92-1068 Planting and Harvesting Information for Nebraska Crops

    Get PDF
    This NebGuide gives information on the normal practices of planting and harvesting crops grown in Nebraska. This publication is a guide for some basic crop management practices for a variety of Nebraska crops. There are many special or unique cropping situations that will require some adjustments to these suggestions

    Efficient routing of single photons by one atom and a microtoroidal cavity

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    Single photons from a coherent input are efficiently redirected to a separate output by way of a fiber-coupled microtoroidal cavity interacting with individual Cesium atoms. By operating in an overcoupled regime for the input-output to a tapered fiber, our system functions as a quantum router with high efficiency for photon sorting. Single photons are reflected and excess photons transmitted, as confirmed by observations of photon antibunching (bunching) for the reflected (transmitted) light. Our photon router is robust against large variations of atomic position and input power, with the observed photon antibunching persisting for intracavity photon number 0.03 \lesssim n \lesssim 0.7

    Variability in bacteriophage and antibiotic sensitivity in serial Pseudomonas aeruginosa isolates from cystic fibrosis airway cultures over 12 months

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    Antibiotic treatment for Pseudomonas aeruginosa (Pa) in cystic fibrosis is limited in efficacy and may lead to multi-drug resistance (MDR). Alternatives such as bacteriophages are being explored but well designed, and controlled trials are crucial. The rational selection of patients with bacteriophage susceptible infections is required for both safety and efficacy monitoring. We questioned whether bacteriophage susceptibility profiles were constant or variable over time, variability having been reported with antibiotics. Serial Pa isolates (n = 102) from 24 chronically infected cystic fibrosis (CF) patients over one year were investigated with plaque and antibiotic disc diffusion assays. Variable number tandem repeat (VNTR) analysis identified those patients with >1 isolate. A median (range) of 4 (3–6) isolates/patient were studied. Twenty-one (87.5%) individuals had a single VNTR type; three (12.5%) had two VNTR types at different times. Seventy-five percent of isolates were sensitive to bacteriophage at ≥ 1 concentration; 50% of isolates were antibiotic multidrug resistant. Serial isolates, even when representing a single VNTR type, varied in sensitivity to both bacteriophages and antibiotics. The rates of sensitivity to bacteriophage supports the development of this therapy; however, the variability in response has implications for the selection of patients in future trials which must be on the basis of current, not past, isolate testing

    Mapping the submillimeter spiral wave in NGC 6946

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    We have analysed SCUBA 850\mum images of the (near) face-on spiral galaxy NGC 6946, and found a tight correlation between dust thermal emission and molecular gas. The map of visual optical depth relates well to the distribution of neutral gas (HI+H2) and implies a global gas-to-dust ratio of 90. There is no significant radial variation of this ratio: this can be understood, since the gas content is dominated by far by the molecular gas. The latter is estimated through the CO emission tracer, which is itself dependent on metallicity, similarly to dust emission. By comparing the radial profile of our visual optical depth map with that of the SCUBA image, we infer an emissivity (dust absorption coefficient) at 850\mum that is 3 times lower than the value measured by COBE in the Milky Way, and 9 times lower than in NGC 891. A decomposition of the spiral structure half way out along the disk of NGC 6946 suggests an interarm optical depth of between 1 and 2. These surprisingly high values represent 40-80% of the visual opacity that we measure for the arm region (abridged).Comment: 12 pages, 9 figures, accepted in A&

    Dense Cloud Ablation and Ram Pressure Stripping of the Virgo Spiral NGC 4402

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    We present optical, HI and radio continuum observations of the highly inclined Virgo Cluster Sc galaxy NGC 4402, which show evidence for ram-pressure stripping and dense cloud ablation. VLA HI and radio continuum maps show a truncated gas disk and emission to the northwest of the main disk emission. In particular, the radio continuum emission is asymmetrically extended to the north and skewed to the west. The Halpha image shows numerous HII complexes along the southern edge of the gas disk, possibly indicating star formation triggered by the ICM pressure. BVR images at 0.5" resolution obtained with the WIYN Tip-Tilt Imager show a remarkable dust lane morphology: at half the optical radius, the dust lane of the galaxy curves up and out of the disk, matching the HI morphology. Large dust plumes extend upward for ~1.5 kpc from luminous young star clusters at the SE edge of the truncated gas disk. These star clusters are very blue, indicating very little dust reddening, which suggests dust blown away by an ICM wind at the leading edge of the interaction. To the south of the main ridge of interstellar material, where the galaxy is relatively clean of gas and dust, we have discovered 1 kpc long linear dust filaments with a position angle that matches the extraplanar radio continuum tail; we interpret this angle as the projected ICM wind direction. One of the observed dust filaments has an HII region at its head. We interpret these dust filaments as large, dense clouds which were initially left behind as the low-density ISM is stripped, but are then ablated by the ICM wind. These results provide striking new evidence on the fate of molecular clouds in stripped cluster galaxies.Comment: 17 pages, 4 figures, accepted for publication in AJ. See ftp://ftp.astro.yale.edu/pub/hugh/papers/crowl_n4402.ps.gz for a version with high-resolution figure
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