682 research outputs found
GASP II. A MUSE view of extreme ram-pressure stripping along the line of sight: kinematics of the jellyfish galaxy JO201
This paper presents a spatially-resolved kinematic study of the jellyfish
galaxy JO201, one of the most spectacular cases of ram-pressure stripping (RPS)
in the GASP (GAs Stripping Phenomena in Galaxies with MUSE) survey. By studying
the environment of JO201, we find that it is moving through the dense
intra-cluster medium of Abell 85 at supersonic speeds along our line of sight,
and that it is likely accompanied by a small group of galaxies. Given the
density of the intra-cluster medium and the galaxy's mass, projected position
and velocity within the cluster, we estimate that JO201 must so far have lost
~50% of its gas during infall via RPS. The MUSE data indeed reveal a smooth
stellar disk, accompanied by large projected tails of ionised (Halpha) gas,
composed of kinematically cold (velocity dispersion <40km/s) star-forming knots
and very warm (>100km/s) diffuse emission which extend out to at least ~50 kpc
from the galaxy centre. The ionised Halpha-emitting gas in the disk rotates
with the stars out to ~6 kpc but in the disk outskirts becomes increasingly
redshifted with respect to the (undisturbed) stellar disk. The observed
disturbances are consistent with the presence of gas trailing behind the
stellar component, resulting from intense face-on RPS happening along the line
of sight. Our kinematic analysis is consistent with the estimated fraction of
lost gas, and reveals that stripping of the disk happens outside-in, causing
shock heating and gas compression in the stripped tails.Comment: ApJ, revised version after referee comments, 15 pages, 16 figures.
The interactive version of Figure 9 can be viewed at
web.oapd.inaf.it/gasp/publications.htm
Directed flow of antiprotons in Au+Au collisions at AGS
Directed flow of antiprotons is studied in Au+Au collisions at a beam
momentum of 11.5A GeV/c. It is shown that antiproton directed flow is
anti-correlated to proton flow. The measured transverse momentum dependence of
the antiproton flow is compared with predictions of the RQMD event generator.Comment: 16 pages, 6 figure
Particles at oil–air surfaces : powdered oil, liquid oil marbles, and oil foam
The type of material stabilized by four kinds of fluorinated particles (sericite and bentonite platelet clays and spherical zinc oxide) in air–oil mixtures has been investigated. It depends on the particle wettability and the degree of shear. Upon vigorous agitation, oil dispersions are formed in all the oils containing relatively large bentonite particles and in oils of relatively low surface tension (γla < 26 mN m⁻¹) like dodecane, 20 cS silicone, and cyclomethicone containing the other fluorinated particles. Particle-stabilized oil foams were obtained in oils having γla > 26 mN m⁻¹ where the advancing air–oil–solid contact angle θ lies between ca. 90° and 120°. Gentle shaking, however, gives oil-in-air liquid marbles with all the oil–particle systems except for cases where θ is <60°. For oils of tension >24 mN m⁻¹ with omniphobic zinc oxide and sericite particles for which advancing θ ≥ 90°, dry oil powders consisting of oil drops in air which do not leak oil could be made upon gentle agitation up to a critical oil:particle ratio (COPR). Above the COPR, catastrophic phase inversion of the dry oil powders to air-in-oil foams was observed. When sheared on a substrate, the dry oil powders containing at least 60 wt % of oil release the encapsulated oil, making these materials attractive formulations in the cosmetic and food industries
Two-Proton Correlations from 14.6A GeV/c Si+Pb and 11.5A GeV/c Au+Au Central Collisions
Two-proton correlation functions have been measured in Si+Pb collisions at
14.6A GeV/c and Au+Au collisions at 11.5A GeV/c by the E814/E877 collaboration.
Data are compared with predictions of the transport model RQMD and the source
size is inferred from this comparison. Our analysis shows that, for both
reactions, the characteristic size of the system at freeze-out exceeds the size
of the projectile, suggesting that the fireball created in the collision has
expanded. For Au+Au reactions, the observed centrality dependence of the
two-proton correlation function implies that more central collisions lead to a
larger source sizes.Comment: RevTex, 12 pages, 5 figure
Tear secretion dysfunction among women workers engaged in light-on tests in the TFT-LCD industry
BACKGROUND: The TFT-LCD (thin film transistor liquid crystal display) industry is rapidly growing in Taiwan and many other countries. A large number of workers, mainly women, are employed in the light-on test process to detect the defects of products. At the light-on test workstation, the operator is generally exposed to low humidity (in the clean room environment), flashing light, and low ambient illumination for long working hours. Many workers complained about eye discomfort, and therefore we conducted a study to evaluate the tear secretion function of light-on test workers of a TFT-LCD company. METHODS: We recruited workers engaged in light-on tests in the company during their periodical health examination. In addition to a questionnaire survey of demographic characteristics and ophthalmic symptoms, we evaluated the tear secretion function of both eyes of each participant using the Schirmer's lacrimal basal secretion test with anaesthesia. A participant with one or both eyes yielding abnormal test results was defined as a case of tear secretion dysfunction. RESULTS: During the study period, a total of 371 light-on test workers received the health examination at the clinic of the park, and 52 of them were excluded due to having ophthalmic diseases and other systemic diseases that may affect ophthalmic function. All the remaining 319 qualified workers agreed to participate in this study, and they were all females working by 4-shift rotations. The average age was 24.2 years old (standard deviation [SD] = 3.8), and the average employment duration was 13.6 months (SD = 5.7). Among the 11 ophthalmic symptoms evaluated, eye dryness was the most prevalent (prevalence = 43.3%). In addition, the prevalence of tear secretion dysfunction in at least one eye was 40.1% (128 cases), and contact lens users had an odds ratio of 1.73 (95% confidence interval = 1.02–2.94) in comparison with non-contact lens users. Comparing the Schirmer's test results of those who also participated in the screening in the previous year, we found 40 of the 156 participants (17.2%) with normal test results in the previous year turned abnormal in 2001. In contrast, only 21 of the 76 participants (9.1%) with abnormal test results in the previous year turned normal, and the difference was statistically significant (p = 0.02 for McNemar's test). CONCLUSION: The prevalence of tear secretion dysfunction in woman workers engaged in light-on tests is high and increases with a one-year duration of employment. The use of contact lens may further increase the risk
The Look-back Time Evolution of Far-Ultraviolet Flux from the Brightest Cluster Elliptical Galaxies at z < 0.2
We present the GALEX UV photometry of the elliptical galaxies in Abell
clusters at moderate redshifts (z < 0.2) for the study of the look-back time
evolution of the UV upturn phenomenon. The brightest elliptical galaxies (M_r <
-22) in 12 remote clusters are compared with the nearby giant elliptical
galaxies of comparable optical luminosity in the Fornax and Virgo clusters. The
sample galaxies presented here appear to be quiescent without signs of massive
star formation or strong nuclear activity, and show smooth, extended profiles
in their UV images indicating that the far-UV (FUV) light is mostly produced by
hot stars in the underlying old stellar population. Compared to their
counterparts in nearby clusters, the FUV flux of cluster giant elliptical
galaxies at moderate redshifts fades rapidly with ~ 2 Gyrs of look-back time,
and the observed pace in FUV - V color evolution agrees reasonably well with
the prediction from the population synthesis models where the dominant FUV
source is hot horizontal-branch stars and their progeny. A similar amount of
color spread (~ 1 mag) in FUV - V exists among the brightest cluster elliptical
galaxies at z ~ 0.1, as observed among the nearby giant elliptical galaxies of
comparable optical luminosity.Comment: Accepted for publication in the Special GALEX ApJ Supplement,
December 200
Maternal corticotropin-releasing hormone is associated with LEP DNA methylation at birth and in childhood: an epigenome-wide study in Project Viva
BackgroundCorticotropin-releasing hormone (CRH) plays a central role in regulating the secretion of cortisol which controls a wide range of biological processes. Fetuses overexposed to cortisol have increased risks of disease in later life. DNA methylation may be the underlying association between prenatal cortisol exposure and health effects. We investigated associations between maternal CRH levels and epigenome-wide DNA methylation of cord blood in offsprings and evaluated whether these associations persisted into mid-childhood.MethodsWe investigated mother-child pairs enrolled in the prospective Project Viva pre-birth cohort. We measured DNA methylation in 257 umbilical cord blood samples using the HumanMethylation450 Bead Chip. We tested associations of maternal CRH concentration with cord blood cells DNA methylation, adjusting the model for maternal age at enrollment, education, maternal race/ethnicity, maternal smoking status, pre-pregnancy body mass index, parity, gestational age at delivery, child sex, and cell-type composition in cord blood. We further examined the persistence of associations between maternal CRH levels and DNA methylation in children's blood cells collected at mid-childhood (n = 239, age: 6.7-10.3 years) additionally adjusting for the children's age at blood drawn.ResultsMaternal CRH levels are associated with DNA methylation variability in cord blood cells at 96 individual CpG sites (False Discovery Rate <0.05). Among the 96 CpG sites, we identified 3 CpGs located near the LEP gene. Regional analyses confirmed the association between maternal CRH and DNA methylation near LEP. Moreover, higher maternal CRH levels were associated with higher blood-cell DNA methylation of the promoter region of LEP in mid-childhood (P < 0.05, β = 0.64, SE = 0.30).ConclusionIn our cohort, maternal CRH was associated with DNA methylation levels in newborns at multiple loci, notably in the LEP gene promoter. The association between maternal CRH and LEP DNA methylation levels persisted into mid-childhood
The importance of dietary calcium consumption in two species of semi-terrestrial grapsoid crabs
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