9,221 research outputs found

    Lyman alpha line formation in starbursting galaxies II. Extremely Thick, Dustless, and Static HI Media

    Full text link
    The Lya line transfer in an extremely thick medium of neutral hydrogen is investigated by adopting an accelerating scheme in our Monte Carlo code to skip a large number of core or resonant scatterings. This scheme reduces computing time significantly with no sacrifice in the accuracy of the results. We applied this numerical method to the Lya transfer in a static, uniform, dustless, and plane-parallel medium. Two types of photon sources have been considered, the midplane source and the uniformly distributed sources. The emergent profiles show double peaks and absorption trough at the line-center. We compared our results with the analytic solutions derived by previous researchers, and confirmed that both solutions are in good agreement with each other. We investigated the directionality of the emergent Lya photons and found that limb brightening is observed in slightly thick media while limb darkening appears in extremely thick media. The behavior of the directionality is noted to follow that of the Thomson scattered radiation in electron clouds, because both Lya wing scattering and Thomson scattering share the same Rayleigh scattering phase function. The mean number of wing scatterings just before escape is in exact agreement with the prediction of the diffusion approximation. The Lya photons constituting the inner part of the emergent profiles follow the relationship derived from the diffusion approximation. We present a brief discussion on the application of our results to the formation of Lya broad absorption troughs and P-Cygni type Lya profiles seen in the UV spectra of starburst galaxies.Comment: 24 papges, 12 figures, The revised version submitted to Ap

    Identification of presumed pathogenic KRT3 and KRT12 gene mutations associated with Meesmann corneal dystrophy.

    Get PDF
    PurposeTo report potentially pathogenic mutations in the keratin 3 (KRT3) and keratin 12 (KRT12) genes in two individuals with clinically diagnosed Meesmann corneal dystrophy (MECD).MethodsSlit-lamp examination was performed on the probands and available family members to identify characteristic features of MECD. After informed consent was obtained, saliva samples were obtained as a source of genomic DNA, and screening of KRT3 and KRT12 was performed. Potentially pathogenic variants were screened for in 200 control chromosomes. PolyPhen-2, SIFT, and PANTHER were used to predict the functional impact of identified variants. Short tandem repeat genotyping was performed to confirm paternity.ResultsSlit-lamp examination of the first proband demonstrated bilateral, diffusely distributed, clear epithelial microcysts, consistent with MECD. Screening of KRT3 revealed a heterozygous missense variant in exon 1, c.250C>T (p.(Arg84Trp)), which has a minor allele frequency of 0.0076 and was not identified in 200 control chromosomes. In silico analysis with PolyPhen-2 and PANTHER predicted the variant to be damaging to protein function; however, SIFT analysis predicted tolerance of the variant. The second proband demonstrated bilateral, diffusely distributed epithelial opacities that appeared gray-white on direct illumination and translucent on retroillumination. Neither parent demonstrated corneal opacities. Screening of KRT12 revealed a novel heterozygous insertion/deletion variant in exon 6, c.1288_1293delinsAGCCCT (p.(Arg430_Arg431delinsSerPro)). This variant was not present in either of the proband's parents or in 200 control chromosomes and was predicted to be damaging by PolyPhen-2, PANTHER, and SIFT. Haplotype analysis confirmed paternity of the second proband, indicating that the variant arose de novo.ConclusionsWe present a novel KRT12 mutation, representing the first de novo mutation and the first indel in KRT12 associated with MECD. In addition, we report a variant of uncertain significance in KRT3 in an individual with MECD. Although the potential pathogenicity of this variant is unknown, it is the first variant affecting the head domain of K3 to be reported in an individual with MECD and suggests that disease-causing variants associated with MECD may not be restricted to primary sequence alterations of either the helix-initiation or helix-termination motifs of K3 and K12

    Two aspects of decadal ENSO variability modulating the long-term global carbon cycle

    Get PDF
    The El Niño–Southern Oscillation (ENSO) drives variations in terrestrial carbon fluxes by affecting the terrestrial ecosystem via atmospheric teleconnections and thus plays an important role in interannual variability of the global carbon cycle. However, we lack such knowledge on decadal time scales, that is, how the carbon cycle can be affected by decadal variations of ENSO characteristics. Here we examine how, and by how much, decadal ENSO variability affects decadal variability of the global carbon cycle by analyzing a 1,801‐year preindustrial control simulation. We identify two different aspects, together explaining ~36% of the decadal variations in the global carbon cycle. First, climate variations induced by decadal ENSO‐like variability regulate terrestrial carbon flux and hence atmospheric CO2 on decadal time scales. Second, decadal changes in the asymmetrical response of the terrestrial ecosystem, resulting from decadal modulation of ENSO amplitude and asymmetry, rectify the background mean state, thereby generating decadal variability of land carbon fluxes

    Dilatonic wormholes: construction, operation, maintenance and collapse to black holes

    Get PDF
    The CGHS two-dimensional dilaton gravity model is generalized to include a ghost Klein-Gordon field, i.e. with negative gravitational coupling. This exotic radiation supports the existence of static traversible wormhole solutions, analogous to Morris-Thorne wormholes. Since the field equations are explicitly integrable, concrete examples can be given of various dynamic wormhole processes, as follows. (i) Static wormholes are constructed by irradiating an initially static black hole with the ghost field. (ii) The operation of a wormhole to transport matter or radiation between the two universes is described, including the back-reaction on the wormhole, which is found to exhibit a type of neutral stability. (iii) It is shown how to maintain an operating wormhole in a static state, or return it to its original state, by turning up the ghost field. (iv) If the ghost field is turned off, either instantaneously or gradually, the wormhole collapses into a black hole.Comment: 9 pages, 7 figure

    Schr\"{o}dinger Fields on the Plane with non-Abelian Chern-Simons Interactions

    Full text link
    Physical content of the nonrelativistic quantum field theory with non-Abelian Chern-Simons interactions is clarified with the help of the equivalent first- quantized description which we derive in any physical gauge.Comment: 12 pages, LaTex, SNUTP 94-1

    Separate muscle bundles of the flexor digitorum superficialis overlying the ulnar nerve

    Get PDF
    Background: The aim of this study was to elucidate the morphological charac­teristics of the muscle bundles of the flexor digitorum superficialis (FDS) attached to the intermuscular aponeurosis (IMA) and any related structure that could potentially compress the ulnar nerve. Materials and methods: Fifty embalmed limbs of 34 adult cadavers were studied. Results: The FDS arose as multiple separate bundles from the IMA of the lateral surface of the flexor carpi ulnaris in 76% of specimens. Below their origin, these separate bundles became attached continuously as a single mass to form the muscle belly. There were 1, 2, 3, 4 and 5 arising FDS muscle bundles in 28%, 30%, 4%, 10% and 4% of specimens, respectively. The muscle bundles were attached either only superficially (24% of cases) or across the entire width (20% of cases) of the IMA. In 32% of the specimens, bundles arose from the IMA in a combined fashion, being attached to the IMA superficially, deep and across the entire structure. The muscle bundles that arose from the deep part or entire width of the IMA were in contact with the ulnar nerve in 52% of specimens. In 11 (22%) specimens, the deep borders of the lowest muscle bundles close to the ulnar nerve were composed of tendinous fibres that divided from the IMA of the lateral surface of the flexor carpi ulnaris. The distance from the medial epicondyle to the lowest point of the FDS arising from the IMA was 62.0 ± 19.7 mm. Conclusions: The thick tendinous deep border of the lowest muscle bundle of the FDS where it attaches to the IMA is a potential cause of ulnar nerve compression

    Direct observation of a liquid film under a vapor environment in a pool boiling using a nanofluid

    Get PDF
    The existence of a liquid film separating a vapor bubble from a heated solid surface is confirmed using a nanofluid. The existence of such a liquid film had been a theoretical premise of the critical heat flux mechanism, significantly difficult to verify through experimental observations. Here, we show that a liquid film under a massive vapor bubble adheres to a heated solid surface. The liquid film comes into being trapped in a dynamic coalescence environment of nucleate bubbles, which grow and depart continuously from the heated surface. In its dryout process, the liquid film displays vapor "holes" originating from the rupture of discrete nucleating bubbles. The dryout process of the liquid film can be understood from the vaporization of rims of the holes and of smooth film region.open51

    Evidence for a Nodeless Gap from the Superfluid Density of Optimally Doped Pr_{1.855}Ce_{0.145}CuO_{4-y} Films

    Full text link
    We present measurements of the ab-plane magnetic penetration depth, \lambda(T), in five optimally doped Pr_{1.855}Ce_{0.145}CuO_{4-y} films for 1.6 K \leq T \leq T_c \sim 24 K. Low resistivities, high superfluid densities n_s(T)\propto \lambda^{-2}(T), high T_c's, and small transition widths are reproducible and indicative of excellent film quality. For all five films, \lambda^{-2}(T)/\lambda^{-2}(0) at low T is well fitted by an exponential temperature dependence with a gap, \Delta_{min}, of 0.85 k_B T_c. This behavior is consistent with a nodeless gap and is incompatible with d-wave superconductivity.Comment: 5 pages, 4 figures, reorganized for clarit
    • 

    corecore