755 research outputs found

    Multiple coaxial rings in the bipolar nebula hubble 12

    Get PDF
    A series of two-dimensional rings along a common axis aligned with the bipolar lobes is found in the planetary nebula Hb 12. The rings have separations of about 0.3″, which can be translated into physical separations of ∼ 1000 AU, or time separations of the order of 50 yr. We suggest that the existence of the rings is a manifestation of the interaction between a time-variable, collimated fast outflow with the circumstellar envelope created by the stellar wind of an asymptotic giant branch star. Comparison of Hb 12 with other bipolar nebulae with hourglass structures such as Hen 2-104, MyCn 18, and SN 1987A suggests that the nebula of Hb 12 may represent the inner nebula of a much larger bipolar structures, and we propose to search for such outer structures with a wide-field infrared camera. © 2007. The American Astronomical Society. All rights reserved.published_or_final_versio

    Picosecond all-optical logic gates (XOR, OR, NOT, and AND) in a fiber optical parametric amplifier

    Get PDF
    We demonstrate all-optical XOR, OR, NOT, and AND gates in a fiber optical parametric amplifier within the same experimental setup. Error-free operation was achieved for 10Gb/s RZ signals with pulsewidth suitable for 100Gb/s operation. © 2007 Optical Society of America.published_or_final_versio

    Ethnic inequities in routine childhood vaccinations in England 2006–2021: an observational cohort study using electronic health records

    Get PDF
    Background: Population groups that are underserved by England's childhood vaccination programme must be identified to address the country's declining vaccination coverage. We examined routine childhood vaccination coverage in England by maternal ethnicity between 2006 and 2021. Methods: We created first, second and fifth birthday cohorts using mother-child linked electronic health records from the Clinical Practice Research Datalink (CPRD) Aurum. After validation against the UK Health Security Agency (UKHSA) and National Health Service England (NHSE) annual statistical reports, we described vaccination coverage for each vaccine by ethnicity and year. We used modified Poisson regression to analyse the effect of ethnicity on receiving the primary and full course of each vaccine. Findings: Up to 1,170,804 children born after 1 April 2006 were included in the first birthday cohort, reducing to 645,492 by the fifth birthday. Children were followed up until 31 March 2021 at the latest. Children born to mothers in 9 minority ethnic groups and those of unknown ethnicity had lower vaccination coverage (61.3–97.5%) than the White British group (79.9–97.8%) for all vaccines. Indian, Pakistani, Bangladeshi, Chinese, Any other Asian background, and White and Asian ethnic groups had similar vaccination coverage to the White British group (above 90% for most vaccines in most years). Inequities particularly affected the Caribbean group (e.g. 61% coverage for the 6/5/4-in-1 full course in 2020–21 by children's fifth birthday; RR 0.66, 95% CI 0.6–0.74 compared with the White British group) and Any other Black, African and Caribbean background (e.g. coverage 68% for the MMR primary course in 2020–21; RR 0.71, 95% CI 0.64–0.78). These inequities widened over the study period. For example, the absolute difference in coverage between the Caribbean and White British groups for the full course of MMR increased from 12% in 2011–12 to 22% in 2019–20. These inequities remained even after accounting for sociodemographic, maternal and birth related factors, and also widened from primary course to full course. Interpretation: Our findings suggest that urgent policy action is needed to address the ethnic inequities throughout England's routine childhood vaccination programme, which have been worsening over time

    [Fe iii] lines in the planetary nebula NGC 2392

    Get PDF
    The Eskimo Nebula (NGC 2392) is a young double-shell planetary nebula (PN). Its intrinsic structure and the responsible shaping mechanism are still not fully understood. We present new optical spectroscopy of NGC 2392 at two different locations to obtain the spectra of the inner and outer shells. Several [Fe iii] lines are clearly detected. We find that these [Fe iii] lines mostly originate from the inner shell. Therefore, we suggest that NGC 2392 might have an intrinsic structure similar to the Ant Nebula Mz 3, which exhibits a number of [Fe iii] lines from the central dense regions. In this scenario, the inner and outer shells correspond to the central emission core and the outer lobes of Mz 3, respectively. © 2012 International Astronomical Union.published_or_final_versio

    Understanding and promoting oral health of Indonesian domestic helpers in Hong Kong

    Get PDF
    Includes bibliographical references (p. 44).published_or_final_versio

    Design and development of an RFID-based HIS - a case study

    Get PDF
    Author name used in this publication: S. K. KwokAuthor name used in this publication: G. T. S. HoAuthor name used in this publication: C. Y. Chan2010-2011 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Lead-free ceramics for pyroelectric applications

    Get PDF
    Author name used in this publication: S. T. LauAuthor name used in this publication: S. H. ChoyAuthor name used in this publication: D. M. LinAuthor name used in this publication: K. W. KwokAuthor name used in this publication: H. L. W. Chan2007-2008 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    The role of survivin in angiogenesis during zebrafish embryonic development

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Survivin is the smallest member of the inhibitor of apoptosis (IAP) gene family. Recently, the zebrafish <it>survivin-1 </it>gene has been cloned, showing remarkable sequence identity and similarity over the BIR domain compared with human and mouse <it>survivin </it>gene. Here we investigated the role of survivin in angiogenesis during zebrafish development. Morpholinos (MOs) targeting the 5' untranslated region (UTR) (Sur<sub>UTR</sub>) and sequences flanking the initiation codon (Sur<sub>ATG</sub>) of zebrafish <it>survivin-1 </it>gene were injected into embryos at 1–4 cell stage. Vasculature was examined by microangiography and GFP expression in <it>Tg(fli1:EGFP)</it><sup><it>y</it>1 </sup>embryos. Results: In embryos co-injected with Sur<sub>UTR </sub>and Sur<sub>ATG</sub>-MOs, vasculogenesis was intact but angiogenesis was markedly perturbed, especially in the inter-segmental vessels (ISV) and dorsal longitudinal anastomotic vessels (DLAV) of the trunk, the inner optic circle and optic veins of developing eyes and the sub-intestinal vessels. Apoptosis was increased, as shown by TUNEL staining and increase in caspase-3 activity. Efficacy of Sur<sub>UTR </sub>and Sur<sub>ATG</sub>-MOs was demonstrated by translation inhibition of co-injected 5'UTR survivin:GFP plasmids. The phenotypes could be recapitulated by splice-site MO targeting the exon2-intron junction of <it>survivin </it>gene and rescued by <it>survivin </it>mRNA. Injection of human vascular endothelial growth factor (VEGF) protein induced ectopic angiogenesis and increased survivin expression, whereas treatment with a VEGF receptor inhibitor markedly reduced angiogenesis and suppressed survivin expression. Conclusion: Survivin is involved in angiogenesis during zebrafish development and may be under VEGF regulation.</p

    Evaluation of anti-oxidant capacity of root of Scutellaria baicalensis Georgi, in comparison with roots of polygonum multiflorum thunb and Panax ginseng CA Meyer

    Get PDF
    Author name used in this publication: Jian-Hong WuAuthor name used in this publication: Alice Lai-Shan AuAuthor name used in this publication: Peter Hoi-Fu Yu2009-2010 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe
    corecore