3,904 research outputs found
Weak-lensing analysis of the z ~ 0.8 cluster CL 0152-1357 with the advanced camera for surveys
No full textWe present a weak-lensing analysis of the X-ray-luminous cluster CL 0152-1357 at z similar or equal to 0.84 using Hubble Space Telescope/Advanced Camera for Surveys (ACS) observations. The unparalleled resolution and sensitivity of ACS enable us to measure weakly distorted, faint background galaxies to the extent that the number density reaches similar to175 arcmin(-2). The point-spread function (PSF) of ACS has a complicated shape that also varies across the field. We construct a PSF model for ACS from an extensive investigation of 47 Tuc stars in a modestly crowded region. We show that this model PSF excellently describes the PSF variation pattern in the cluster observation when a slight adjustment of ellipticity is applied. The high number density of source galaxies and the accurate removal of the PSF effect through moment-based deconvolution allow us to restore the dark matter distribution of the cluster in great detail. The direct comparison of the mass map with the X-ray morphology from Chandra observations shows that the two peaks of intracluster medium traced by X-ray emission are lagging behind the corresponding dark matter clumps, indicative of an ongoing merger. The overall mass profile of the cluster can be well described by an NFW profile with a scale radius of r(s) = 309 +/- 45 kpc and a concentration parameter of c = 3.7 +/- 0.5. The mass estimates from the lensing analysis are consistent with those from X-ray and Sunyaev-Zel'dovich analyses. The predicted velocity dispersion is also in good agreement with the spectroscopic measurement from VLT observations. In the adopted cosmology where Omega(M) = 0.27, Omega(Lambda) = 0.73, and h = 0.71, the total projected mass and the mass-to-light ratio within 1 Mpc are estimated to be (4.92 +/- 0.44) x 10(14) M-circle dot and 95 +/- 8 M-circle dot/L-Bcircle dot, respectively
Self-compression of 4.9 µm pulses to sub-40 fs with 2 mJ energy in Zinc Sulfide
No full textNonlinear self-compression of few-cycle multi-mJ pulses at 4.9 µm in ZnS is presented. 80 fs input pulses are compressed to 37 fs with 2.1 mJ energy at a 1 kHz repetition rate. © 2024 The Author(s
p53 and cell-cycle-regulated protein expression in small intestinal cells after fast-neutron irradiation in mice
No full textThe involvement of the p53 gene in apoptosis of many cell types towards gamma-radiation is well established. However, little information is available on the relationship between p53 status and cells' ability to undergo apoptosis following exposure to fast neutrons. The aim of this study was to characterize the apoptotic pathway traveled by neutrons in mouse intestinal crypt cells. Each mouse received whole body doses of 0.25-8 Gy fast neutrons and were sacrificed 0, 4, 6, 12, 24, 48, and 72 h, respectively, after irradiation. Apoptosis of crypt cells and expression of p53, cyclin A, cyclin B, cyclin D, and cyclin E were measured. The apoptosis in crypt cells was maximal at 4 and 6 h after irradiation, showing a gradual decline at 24 h. The highest frequency of apoptosis was seen at a 1 Gy dose and then declined gradually beyond a 2 Gy dose with high levels of damage. In immunoblot analysis, apoptosis was confirmed to be dependent on p53 function after fast-neutron irradiation. In addition, cyclin B1, cyclin D, and cyclin E were overexpressed in intestinal cells after fast-neutron irradiation and their immunoreactivities were increased strongly in round and oval cells of laminar propria in villi core and crypts. The results of the current study suggest that apoptosis in crypt cells shows a time- and dose-dependent increase after fast-neutron irradiation. In addition, fast-neutron-induced apoptosis in mouse intestinal crypt cells appears to be related to the increase in functional p53 proteins to a level sufficient to initiate apoptosis and up-regulation of cell-cycle-regulated proteins, which may lead to resistance to DNA damage through cell cycle arrest, is involved deeply in protection of gastrointestinal cells after low doses of fast-neutron irradiation
Correction to: Chamoun et al., Bacterial pathogenesis and interleukin-17: interconnecting mechanisms of immune regulation, host genetics, and microbial virulence that influence severity of infection
No full textChamoun MN, Blumenthal A, Sullivan MJ, Schembri MA, Ulett GC. 2018. Bacterial pathogenesis and interleukin-17: interconnecting mechanisms of immune regulation, host genetics, and microbial virulence that influence severity of infection. Critical Reviews in Microbiology. https://doi.org/10.1080/1040841X.2018.1426556.
When the above article was first published online, the below three corrections were missed.
The author ‘Antje Blumenthal’ was wrongly affiliated to the affiliation “cSchool of Chemistry and Molecular Biosciences, and Australian Infectious Disease Research Centre, The University of Queensland, Brisbane, Australia”. Now this affiliation has been removed for this author.
The affiliation ‘bTranslational Research Institute, The University of Queensland Diamantina Institute, Woolloongabba, Australia’ of the author ‘Antje Blumenthal’ should read ‘bThe University of Queensland Diamantina Institute, Translational Research Institute, Brisbane, Australia’.
In Table 3, the sentence ‘Benefit of manipulating IL-17 levels to improve immunization strategies M. tuberculosis’ should read “Benefit of manipulating IL-17 levels to improve immunization strategies against M. tuberculosis”.No Full Tex
Generation of 22-mJ, 2.0-ps Pulses from a 1-kHz Ho:YLF Regenerative Chirped Pulse Amplifier
No full textWe report a CW-pumped Ho:YLF regenerative amplifier (RA) delivering pulses with 22.5-mJ energy and 2.0-ps duration at 1 kHz. The RA emitting at 2051 nm is broadband-seeded and implemented in a chirped pulse amplification system. © 2024 The Author(s
Superconducting properties in heavily overdoped Ba(Fe0.86Co0.14)2As2 single crystals
No full textWe report the intrinsic superconducting parameters in a heavily overdoped Ba(Fe1-xCox)(2)As-2 (x=0.14) single crystal and their influence in the resulting vortex dynamics. We find a bulk superconducting critical temperature of 9.8 K, magnetic penetration depth lambda(ab) (0)=660 +/- 50 nm, coherence length xi(ab) (0)=6.4 +/- 0.2 nm, and the upper critical field anisotropy gamma(T -> Tc) approximate to 3.7. The vortex phase diagram, in comparison with the optimally doped compound, presents a narrow collective creep regime. The intrinsic pinning energy plays an important role in the resulting vortex dynamics as compared with similar pinning landscape and comparable intrinsic thermal fluctuations. (C) 2014 Elsevier Ltd. All rights reserved.X1111Ysciescopu
Pure-rotational 1D-CARS spatiotemporal thermometry with a single regenerative amplifier system
No full textWe report spatiotemporal pure-rotational coherent anti-Stokes Raman spectroscopy (CARS) in a one-dimensional imaging arrangement obtained with a single ultrafast regenerative amplifier system. The femtosecond pump/Stokes photon pairs, used for impulsive excitation, are delivered by an external compressor operating on a ∼35% beam split of the uncompressed amplifier output (2.5 mJ/pulse). The picosecond 1.2 mJ probe pulse is produced via the second-harmonic bandwidth compression (SHBC) of the ∼65% remainder of the amplifier output (4.5 mJ/pulse), which originates from the internal compressor. The two pump/Stokes and probe pulses are spatially, temporally, and repetition-wise correlated at the measurement, and the signal generation plane is relayed by a wide-field coherent imaging spectrometer onto the detector plane, which is refreshed at the same repetition rate as the ultrafast regenerative amplifier system. We demonstrate 1 kHz cinematographic 1D-CARS gas-phase thermometry across an unstable premixed methane/air flame-front, achieved with a single-shot precision <1% and accuracy <3%, 1.4 mm field of view, and an excellent <20 µm line-spread function.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Flight Performance and Propulsio
Discovery of a very bright strongly lensed galaxy candidate at z ~ 7.6
No full textUsing Hubble Space Telescope (HST) and Spitzer IRAC imaging, we report the discovery of a very bright strongly lensed Lyman break galaxy (LBG) candidate at z similar to 7.6 in the field of the massive galaxy clusterAbell 1689 (z = 0.18). The galaxy candidate, which we refer to as A1689-zD1, shows a strong z(850) - J(110) break of at least 2.2 mag and is completely undetected (= 25). . A1689- zD1 has an observed (lensed) magnitude of 24.7 AB (8 sigma) in the NICMOS H(160) band and is similar to 1.3 mag brighter than the brightest known z(850)-dropout galaxy. When corrected for the cluster magnification of similar to 9.3 at z similar to 7.6, the candidate has an intrinsic magnitude of H(160) = 27.1 AB, or about an L(*) galaxy at z similar to 7: 6. The source- plane deprojection shows that the star formation is occurring in compact knots of size less than or similar to 300 pc. The best- fit stellar population synthesis models yield a median redshift of 7.6, stellar masses (1.6-3.9) x 10(9) M(circle dot), stellar ages 45-320 Myr, star formation rates less than or similar to 7.6M(circle dot) yr(-1), and low reddening with A(V) 7.0 galaxy candidate found to date
Evolution of the color-magnitude relation in high-redshift clusters: Early-type galaxies in the lynx supercluster at z similar to 1.26
No full textColor-magnitude relations (CMRs) have been derived in two high-redshift clusters, RX J0849+4452 and RX J0848+4453 ( with redshifts of z = 1.26 and 1.27, respectively), that lie in the highest redshift cluster superstructure known today, the Lynx Supercluster. The CMR was determined from ACS imaging in the WFC F775W (i(775)) and F850LP (z(850)) filters combined with ground-based spectroscopy. Early-type cluster candidates have been identified according to the Postman et al. morphological classification. In both clusters the bright red early-type population defines a tight CMR very similar in color, although the two clusters present different X-ray luminosities and shapes. The elliptical galaxy CMRs in RX J0849+4452 and RX J0848+4453 show an intrinsic (i(775) - z(850)) color scatter of 0.026 +/- 0.012 and 0.024 +/- 0.015 mag, respectively, within 2' (similar to 1 Mpc at z = 1.26) from the cluster X-ray emission centers. Simple modeling of the scatters using stellar population models from Bruzual and Charlot gives a mean luminosity-weighted age (t) over bar > 2.5 Gyr (z(f) > 2.75) and (t) over bar > 2.6 Gyr (z(f) > 2.8) for ellipticals in RXJ0849+4452 and RX J0848+4453, respectively. S0 galaxies follow the elliptical CMR; they show larger scatters about the CMR. The intrinsic scatter decreases and the CMR slopes are steeper at smaller radii, within both clusters. Within 10 from the cluster X-ray emission centers, elliptical CMR scatters imply a mean luminosity-weighted age (t) over bar > 3.2 Gyr (z(f) > 3.7). We conclude that old stellar populations in cluster elliptical galaxies are already in place at z = 1.26, both in the more evolved cluster RX J0849+4452 and in its less evolved companion RX J0848+4453. Even at a look-back time of 9 Gyr, in the early merging and buildup of massive clusters, the bulk of the stellar content of the bright elliptical galaxy population was in place - apparently formed some 2.5 Gyr earlier at z similar to 3
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