9,262 research outputs found
Young star clusters in circumnuclear starburst rings
We analyse the cluster luminosity functions (CLFs) of the youngest star
clusters in three galaxies exhibiting prominent circumnuclear starburst rings.
We focus specifically on NGC 1512 and NGC 6951, for which we have access to
H data that allow us to unambiguously identify the youngest sample
clusters. To place our results on a firm statistical footing, we first explore
in detail a number of important technical issues affecting the process from
converting the observational data into the spectral-energy distributions of the
objects in our final catalogues. The CLFs of the young clusters in both
galaxies exhibit approximate power-law behaviour down to the 90 per cent
observational completeness limits, thus showing that star cluster formation in
the violent environments of starburst rings appears to proceed similarly as
that elsewhere in the local Universe. We discuss this result in the context of
the density of the interstellar medium in our starburst-ring galaxies.Comment: 14 pages, incl. 12 figures. Accepted for publication in MNRA
The lifetime cost estimation of human papillomavirus-related diseases in China : a modeling study
Objectives: To estimate the lifetime treatment costs of patients with human papillomavirus (HPV) infection-related diseases in China and to provide cost estimates for the economic evaluation of HPV intervention strategies. Methods: We extracted real-world hospital data from 2012 to 2019 and screened for subjects who met the criteria of clinical diagnosis of HPV-related diseases to obtain country-specific inputs into a Markov decision model. The model simulated lifetime treatment costs for HPV from the perspective of a national payer. A 5% discount rate was applied. Costs were converted and inflated to 2020 US dollars (USD) Results: Using 2021 as the base year, the lifetime costs per patient for carcinoma in situ, local metastasis, and distant metastasis cervical cancer are 19,562 (95%CI: 14,456-25,567), and 17,593 (95%CI: 14,962-23,596), 22,411 (95%CI: 12,172-22,249), respectively. The base-case lifetime cost per patient for different stages of vulvar cancer/penile cancer/anal cancer/oral cancer/oropharyngeal cancer/laryngeal cancer falls within 58,236. Conclusions: Using real-world data, we calculated lifetime treatment costs of HPV-related cancer in China and found that the lifetime cost for patients exceeded $17,000 for various stages of disease. The national burden of HPV-related disease could be significantly reduced by eliminating HPV infection
An electron microscopy study of the effect of Ce on plasma sprayed bronze coatings
The Cu-Al eutectoid alloy is an excellent material for mould due to its superior low friction. The conventional sand casting technique, however, is not feasible to fabricate high Al bronze because of high hardness and brittleness. Plasma arc spray has been used to produce high Al/Fe bronze coatings for mould. The inherent impurities such as H, O, N, S during the spray, however, may affect the coating's mechanical strength. One approach is to utilise the active rare earth Ce to clean up these impurities. The study is to investigate the effect of Ce on the microstructure, which has few reported in the literature<br/
The meson annihilation to leptons and inclusive light hadrons
The annihilation of the meson to leptons and inclusive light hadrons is
analyzed in the framework of nonrelativistic QCD (NRQCD) factorization. We find
that the decay mode, which escapes from the helicity suppression, contributes a
sizable fraction width. According to the analysis, the branching ratio due to
the contribution from the color-singlet component of the meson can be of
order (10^{-2}). We also estimate the contributions from the color-octet
components. With the velocity scaling rule of NRQCD, we find that the
color-octet contributions are sizable too, especially, in certain phase space
of the annihilation they are greater than (or comparative to) the color-singlet
component. A few observables relevant to the spectrum of charged lepton are
suggested, that may be used as measurements on the color-octet and
color-singlet components in the future experiments. A typical long
distance contribution in the annihilation is estimated too.Comment: 26 pages, 5 figures (6 eps-files), submitted to Phys. Rev.
Expression of Inwardly Rectifying Potassium Channels by an Inducible Adenoviral Vector Reduced the Neuronal Hyperexcitability and Hyperalgesia Produced by Chronic Compression of the Spinal Ganglion
BACKGROUND: A chronic compressed dorsal root ganglion (CCD) in rat produces pain behavior and an enhanced excitability of neurons within the compressed ganglion. Kir2.1 is an inwardly rectifying potassium channel that acts to stabilize the resting potential of certain cell types. We hypothesized that an inducible expression of Kir2.1 channels in CCD neurons might suppress neuronal excitability in the dorsal root ganglion (DRG) and reduce the associated pain behavior. RESULTS: We delivered, by microinjection into the fourth lumbar (L4) DRG, an adenoviral vector containing a reporter gene encoding the enhanced green fluorescent protein (GFP) and a Kir2.1 channel (AdKir). At the same time the ganglion was compressed by implantation of a rod through the intervertebral foramen (CCD). The in vivo expression of the transferred gene was controlled by an ecdysone analog via an ecdysone-inducible promoter in the viral vector. In comparison with the effects of vehicle or a control vector containing only the GFP gene, AdKir significantly reduced the neuronal hyperexcitability after CCD. Electrophysiological recordings, in vivo, from nociceptive and non-nociceptive DRG neurons expressing the virally produced Kir2.1 channels revealed a hyperpolarized resting membrane potential, an increased rheobase, and lack of spontaneous activity. Inducing the Kir2.1 gene at the beginning of CCD surgery partially prevented the development of mechanical hyperalgesia. However, a delayed induction of the Kir2.1 gene (3 days after CCD surgery) produced no significant effect on the pain behavior. CONCLUSIONS: We found that an inducible expression of Kir2.1 channels in chronically compressed DRG neurons can effectively suppress the neuronal excitability and, if induced at the beginning of CCD injury, prevent the development of hyperalgesia. We hypothesize that a higher level of neuronal hyperexcitability in the DRG is required to initiate than to maintain the hyperalgesia and that the hyperexcitability contributing to neuropathic pain is best inhibited as soon as possible after injury
On Two-Body Decays of A Scalar Glueball
We study two body decays of a scalar glueball. We show that in QCD a spin-0
pure glueball (a state only with gluons) cannot decay into a pair of light
quarks if chiral symmetry holds exactly, i.e., the decay amplitude is chirally
suppressed. However, this chiral suppression does not materialize itself at the
hadron level such as in decays into and , because in
perturbative QCD the glueball couples to two (but not one) light quark pairs
that hadronize to two mesons. Using QCD factorization based on an effective
Lagrangian, we show that the difference of hadronization into and
already leads to a large difference between and , even the decay amplitude is not chirally suppressed. Moreover,
the small ratio of of
measured in experiment does not imply to be a pure glueball. With
our results it is helpful to understand the partonic contents if or is measured reliably.Comment: revised versio
The Structure and Morphology of Galaxies during the Epoch of Reionization Revealed by JWST
We analyze 347 galaxies at redshift using JWST observations from
the CEERS program by fitting a two-dimensional parametric model simultaneously
to the seven-filter NIRCam images to measure the overall structural parameters
and quantify the global properties of the galaxies in the rest-frame optical
band. Particular attention is devoted to deriving robust uncertainties that
include, among other factors, the influence of cosmological surface brightness
dimming and resolution effects. Using the global S\'ersic index () and
observed axial ratio () as a guide, we place a conservative lower
limit of on the incidence of galactic disks. Galaxies follow a
relation between rest-frame optical luminosity and effective radius in the
redshift range , as well as separately over the intervals
and , with a very similar slope but a marginally lower zero
point in the higher redshift bin ( kpc) compared to the
lower redshift bin ( kpc). Within the limitations of the
current sample size, we find no significant redshift evolution of or
at these early epochs.Comment: 23 pages, 17 figures, 2 tables, accepted for publication in The
Astrophysical Journa
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