7,581 research outputs found
Sarcoidosis presenting as granulomatous myositis in a 16-year-old adolescent
BACKGROUND: Sarcoidosis is a multi-system disease characterized by the presence of non-caseating epithelioid granulomas in affected tissues, including skeletal muscle. These organized collections of immune cells have important pathophysiologic action including cytokine production leading to inflammation as well as enzymatic conversion of cholecalciferol to calcitriol via 1-α hydroxylase. There are limited reports of isolated granulomatous myositis causing hypercalcemia in pediatric patients. Our patient uniquely presented with symptoms from hypercalcemia and renal insufficiency caused by an overwhelming burden of granulomatous myositis in her lower extremities, but was otherwise asymptomatic. CASE PRESENTATION: A 16 year old Caucasian female presented with protracted symptoms of fatigue, nausea and prominent weight loss with laboratory evidence of hypercalcemia and renal insufficiency. She lacked clinical and physical findings of arthritis, weakness, rash, uveitis, fever, lymphadenopathy or respiratory symptoms. After extensive negative investigations, re-examination yielded subtle soft tissue changes in her lower extremities, with striking MRI findings of extensive myositis without correlative weakness or serum enzyme elevation. Biopsy showed the presence of non-caseating epithelioid granulomas and calcium oxalate crystals. The patient responded well to prednisone and methotrexate but relapsed with weaning of steroids. She reachieved remission with addition of adalimumab. CONCLUSIONS: Sarcoidosis should be considered in patients presenting with symptomatic hypercalcemia with no apparent causes and negative routine workup. The absences of decreased muscle strength or elevated muscle enzymes do not preclude the diagnosis of granulomatous myositis
The Large-scale and Small-scale Clustering of Lyman-Break Galaxies at 3.5 < z< 5.5 from the GOODS survey
We report on the angular correlation function of Lyman-break galaxies (LBGs)
at z~4 and 5 from deep samples obtained from the Great Observatories Deep
Origins Survey (GOODS). Similar to LBGs at z~3, the shape of w(theta) of the
GOODS LBGs is well approximated by a power-law with slope beta~0.6 at angular
separation theta > 10 arcsec. The clustering strength of z~4, 5 LBGs also
depends on the rest-frame UV luminosity, with brighter galaxies more strongly
clustered than fainter ones, implying a general correlation between halos' mass
and LBGs' star-formation rate. At smaller separations, w(theta) of deep samples
significantly exceeds the extrapolation of the large-scale power-law fit,
implying enhanced spatial clustering at scales r < 1 Mpc. We also find that
bright LBGs statistically have more faint companions on scales theta < 20
arcsec than fainter ones, showing that the enhanced small-scale clustering is
very likely due to sub-structure, namely the fact that massive halos can host
multiple galaxies. A simple model for the halo occupation distribution and the
CDM halo mass function reproduce well the observed w(theta). The scaling
relationship of the clustering strength with volume density and with redshift
is quantitatively consistent with that of CDM halos. A comparison of the
clustering strength of three samples of equal luminosity limit at z ~ 3, 4 and
5 shows that the LBGs at z~5 are hosted in halos about one order of magnitude
less massive than those in the lower redshift bins, suggesting that
star-formation was more efficient at higher-redshift.Comment: replaced with the version accepted for publication in ApJ. 46 pages,
10 figures; minor changes to text, one subsection adde
Modulation of synaptic function by VAC14, a protein that regulates the phosphoinositides PI(3,5)P 2 and PI(5)P
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102191/1/embj2012200.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/102191/2/embj2012200-sup-0001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/102191/3/embj2012200-reviewer_comments.pd
2MASS Galaxies in the Fornax Cluster Spectroscopic Survey
The Fornax Cluster Spectroscopic Survey (FCSS) is an all-object survey of a
region around the Fornax Cluster of galaxies undertaken using the 2dF
multi-object spectrograph on the Anglo-Australian Telescope. Its aim was to
obtain spectra for a complete sample of all objects with 16.5 < b_j < 19.7
irrespective of their morphology (i.e. including `stars', `galaxies' and
`merged' images). We explore the extent to which (nearby) cluster galaxies are
present in 2MASS. We consider the reasons for the omission of 2MASS galaxies
from the FCSS and vice versa. We consider the intersection (2.9 square degrees
on the sky) of our data set with the infra-red 2 Micron All-Sky Survey (2MASS),
using both the 2MASS Extended Source Catalogue (XSC) and the Point Source
Catalogue (PSC). We match all the XSC objects to FCSS counterparts by position
and also extract a sample of galaxies, selected by their FCSS redshifts, from
the PSC. We confirm that all 114 XSC objects in the overlap sample are
galaxies, on the basis of their FCSS velocities. A total of 23 Fornax Cluster
galaxies appear in the matched data, while, as expected, the remainder of the
sample lie at redshifts out to z = 0.2 (the spectra show that 61% are early
type galaxies, 18% are intermediate types and 21% are strongly star
forming).The PSC sample turns out to contain twice as many galaxies as does the
XSC. However, only one of these 225 galaxies is a (dwarf) cluster member. On
the other hand, galaxies which are unresolved in the 2MASS data (though almost
all are resolved in the optical) amount to 71% of the non-cluster galaxies with
2MASS detections and have redshifts out to z=0.32.Comment: 5 pages, accepted by A&A, resubmitted due to missing reference
The ACS LCID project. X. The Star Formation History of IC 1613: Revisiting the Over-Cooling Problem
We present an analysis of the star formation history (SFH) of a field near
the half light radius in the Local Group dwarf irregular galaxy IC 1613 based
on deep Hubble Space Telescope Advanced Camera for Surveys imaging. Our
observations reach the oldest main sequence turn-off, allowing a time
resolution at the oldest ages of ~1 Gyr. Our analysis shows that the SFH of the
observed field in IC 1613 is consistent with being constant over the entire
lifetime of the galaxy. These observations rule out an early dominant episode
of star formation in IC 1613. We compare the SFH of IC 1613 with expectations
from cosmological models. Since most of the mass is in place at early times for
low mass halos, a naive expectation is that most of the star formation should
have taken place at early times. Models in which star formation follows mass
accretion result in too many stars formed early and gas mass fractions which
are too low today (the "over-cooling problem"). The depth of the present
photometry of IC 1613 shows that, at a resolution of ~1 Gyr, the star formation
rate is consistent with being constant, at even the earliest times, which is
difficult to achieve in models where star formation follows mass assembly.Comment: 13 pages, 12 figures, accepted for publication in the Ap
The Star Formation History and Dust Content in the Far Outer Disc of M31
We present a detailed analysis of two fields located 26 kpc (~5 scalelengths)
from the centre of M31. One field samples the major axis populations--the Outer
Disc field--while the other is offset by ~18' and samples the Warp in the
stellar disc. The CMDs based on HST/ACS imaging reach old main-sequence
turn-offs (~12.5 Gyr). We apply the CMD-fitting technique to the Warp field to
reconstruct the star formation history (SFH). We find that after undergoing
roughly constant SF until about 4.5 Gyr ago, there was a rapid decline in
activity and then a ~1.5 Gyr lull, followed by a strong burst lasting 1.5 Gyr
and responsible for 25% of the total stellar mass in this field. This burst
appears to be accompanied by a decline in metallicity which could be a
signature of the inflow of metal-poor gas. The onset of the burst (~3 Gyr ago)
corresponds to the last close passage of M31 and M33 as predicted by detailed
N-body modelling, and may have been triggered by this event. We reprocess the
deep M33 outer disc field data of Barker et al. (2011) in order to compare
consistently-derived SFHs. This reveals a similar duration burst that is
exactly coeval with that seen in the M31 Warp field, lending further support to
the interaction hypothesis. The complex SFHs and the smoothly-varying
age-metallicity relations suggest that the stellar populations observed in the
far outer discs of both galaxies have largely formed in situ rather than
migrated from smaller galactocentric radii. The strong differential reddening
affecting the CMD of the Outer Disc field prevents derivation of the SFH.
Instead, we quantify this reddening and find that the fine-scale distribution
of dust precisely follows that of the HI gas. This indicates that the outer HI
disc of M31 contains a substantial amount of dust and therefore suggests
significant metal enrichment in these parts, consistent with inferences from
our CMD analysis.Comment: Abstract shortened. 17 pages, 12 figures (+ 6 pages & 5 figures in
Appendix). MNRAS, in pres
The ISLAndS project II: The Lifetime Star Formation Histories of Six Andromeda dSphs
The Initial Star formation and Lifetimes of Andromeda Satellites (ISLAndS)
project uses Hubble Space Telescope imaging to study a representative sample of
six Andromeda dSph satellite companion galaxies. The main goal of the program
is to determine whether the star formation histories (SFHs) of the Andromeda
dSph satellites demonstrate significant statistical differences from those of
the Milky Way, which may be attributable to the different properties of their
local environments. Our observations reach the oldest main sequence turn-offs,
allowing a time resolution at the oldest ages of ~ 1 Gyr, which is comparable
to the best achievable resolution in the MW satellites. We find that the six
dSphs present a variety of SFHs that are not strictly correlated with
luminosity or present distance from M31. Specifically, we find a significant
range in quenching times (lookback times from 9 to 6 Gyr), but with all
quenching times more than ~ 6 Gyr ago. In agreement with observations of Milky
Way companions of similar mass, there is no evidence of complete quenching of
star formation by the cosmic UV background responsible for reionization, but
the possibility of a degree of quenching at reionization cannot be ruled out.
We do not find significant differences between the SFHs of the three members of
the vast, thin plane of satellites and the three off-plane dSphs. The primary
difference between the SFHs of the ISLAndS dSphs and Milky Way dSph companions
of similar luminosities and host distances is the absence of very late
quenching (< 5 Gyr ago) dSphs in the ISLAndS sample. Thus, models that can
reproduce satellite populations with and without late quenching satellites will
be of extreme interest.Comment: 24 pages, 11 figures, 3 tables, submitted to the Ap
Cover crop productivity and subsequent soybean yield in the western Corn Belt
Cover crops (CC) in corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] rotations may prevent N loss and provide other ecosystem services but CC productivity in the western Corn Belt is limited by the short growing season. Our objective was to assess CC treatment and planting practice effects on CC biomass, spring soil nitrate concentrations, and soybean yield at two rainfed sites in eastern and one irrigated site in south-central Nebraska over 4 yr. Cover crop treatments (cereal rye [Secale cereale L.] [RYE] and a mix of rye, legume, and brassica species [MIX]) were planted by broadcast interseeding into corn stands in September (pre-harvest broadcast) or drilling after corn harvest (post-harvest drilled) and terminated 2 wk before planting soybean. Cover crop biomass and N uptake varied between years, but generally at the eastern sites, pre-harvest broadcasting produced more biomass than post-harvest drilling (1.64 and 0.79 Mg haâ1, respectively) and had greater N uptake (37 and 24 kg haâ1, respectively). At the south-central site, post-harvest drilling produced more than pre-harvest broadcasting (1.44 and 1.20 Mg haâ1, respectively). RYE had more biomass than MIX (1.41 and 1.09 Mg haâ1, respectively), but the same N uptake. Soil nitrate reductions after CC were small. In 3 of 12 site-years, soybean yielded less after pre-harvest CC. Yield reductions were not correlated to CC biomass, but were likely due to greater weed pressure. High CC productivity is necessary for high N uptake, and requires site-specific selection of planting practice and CC treatments
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