1,083 research outputs found
Red Nuggets at z~1.5: Compact passive galaxies and the formation of the Kormendy Relation
We present the results of NICMOS imaging of a sample of 16 high mass
passively evolving galaxies with 1.3<z<2, taken primarily from the Gemini Deep
Deep Survey. Around 80% of galaxies in our sample have spectra dominated by
stars with ages >1 Gyr. Our rest-frame R-band images show that most of these
objects have compact regular morphologies which follow the classical R^1/4 law.
These galaxies scatter along a tight sequence in the Kormendy relation. Around
one-third of the massive red objects are extraordinarily compact, with
effective radii under one kiloparsec. Our NICMOS observations allow the
detection of such systems more robustly than is possible with optical
(rest-frame UV) data, and while similar systems have been seen at z>2, this is
the first time such systems have been detected in a rest-frame optical survey
at 1.3<z<2. We refer to these compact galaxies as "red nuggets". Similarly
compact massive galaxies are completely absent in the nearby Universe. We
introduce a new "stellar mass Kormendy relation" (stellar mass density vs size)
which isolates the effects of size evolution from those of luminosity and color
evolution. The 1.1 < z < 2 passive galaxies have mass densities that are an
order of magnitude larger then early type galaxies today and are comparable to
the compact distant red galaxies at 2 < z < 3. We briefly consider mechanisms
for size evolution in contemporary models focusing on equal-mass mergers and
adiabatic expansion driven by stellar mass loss. Neither of these mechanisms
appears able to transform the high-redshift Kormendy relation into its local
counterpart. Comment: Accepted version (to appear in ApJ
Botulinum toxin type A injections for the management of muscle tightness following total hip arthroplasty: a case series
<p>Abstract</p> <p>Background</p> <p>Development of hip adductor, tensor fascia lata, and rectus femoris muscle contractures following total hip arthroplasties are quite common, with some patients failing to improve despite treatment with a variety of non-operative modalities. The purpose of the present study was to describe the use of and patient outcomes of botulinum toxin injections as an adjunctive treatment for muscle tightness following total hip arthroplasty.</p> <p>Methods</p> <p>Ten patients (14 hips) who had hip adductor, abductor, and/or flexor muscle contractures following total arthroplasty and had been refractory to physical therapeutic efforts were treated with injection of botulinum toxin A. Eight limbs received injections into the adductor muscle, 8 limbs received injections into the tensor fascia lata muscle, and 2 limbs received injection into the rectus femoris muscle, followed by intensive physical therapy for 6 weeks.</p> <p>Results</p> <p>At a mean final follow-up of 20 months, all 14 hips had increased range in the affected arc of motion, with a mean improvement of 23 degrees (range, 10 to 45 degrees). Additionally all hips had an improvement in hip scores, with a significant increase in mean score from 74 points (range, 57 to 91 points) prior to injection to a mean of 96 points (range, 93 to 98) at final follow-up. There were no serious treatment-related adverse events.</p> <p>Conclusion</p> <p>Botulinum toxin A injections combined with intensive physical therapy may be considered as a potential treatment modality, especially in difficult cases of muscle tightness that are refractory to standard therapy.</p
Interfaces of Modulated Phases
Numerically minimizing a continuous free-energy functional which yields
several modulated phases, we obtain the order-parameter profiles and
interfacial free energies of symmetric and non-symmetric tilt boundaries within
the lamellar phase, and of interfaces between coexisting lamellar, hexagonal,
and disordered phases. Our findings agree well with chevron, omega, and
T-junction tilt-boundary morphologies observed in diblock copolymers and
magnetic garnet films.Comment: 4 page
A CANDELS - 3D-HST Synergy: Resolved Star Formation Patterns at 0.7 < z < 1.5
We analyze the resolved stellar populations of 473 massive star-forming
galaxies at 0.7 < z < 1.5, with multi-wavelength broad-band imaging from
CANDELS and Halpha surface brightness profiles at the same kiloparsec
resolution from 3D-HST. Together, this unique data set sheds light on how the
assembled stellar mass is distributed within galaxies, and where new stars are
being formed. We find the Halpha morphologies to resemble more closely those
observed in the ACS I band than in the WFC3 H band, especially for the larger
systems. We next derive a novel prescription for Halpha dust corrections, which
accounts for extra extinction towards HII regions. The prescription leads to
consistent SFR estimates and reproduces the observed relation between the
Halpha/UV luminosity ratio and visual extinction, both on a pixel-by-pixel and
on a galaxy-integrated level. We find the surface density of star formation to
correlate with the surface density of assembled stellar mass for spatially
resolved regions within galaxies, akin to the so-called 'main sequence of star
formation' established on a galaxy-integrated level. Deviations from this
relation towards lower equivalent widths are found in the inner regions of
galaxies. Clumps and spiral features, on the other hand, are associated with
enhanced Halpha equivalent widths, bluer colors, and higher specific star
formation rates compared to the underlying disk. Their Halpha/UV luminosity
ratio is lower than that of the underlying disk, suggesting the ACS clump
selection preferentially picks up those regions of elevated star formation
activity that are the least obscured by dust. Our analysis emphasizes that
monochromatic studies of galaxy structure can be severely limited by
mass-to-light ratio variations due to dust and spatially inhomogeneous star
formation histories.Comment: Accepted by The Astrophysical Journal, 18 pages, 1 table, 10 figure
Astrocytes regulate GLP-1 receptor-mediated effects on energy balance
© 2016 the authors. Astrocytes are well established modulators of extracellular glutamate, but their direct influence on energy balance-relevant behaviors is largely understudied. As the anorectic effects of glucagon-like peptide-1 receptor (GLP-1R) agonists are partly mediated by central modulation of glutamatergic signaling, we tested the hypothesis that astrocytic GLP-1R signaling regulates energy balance in rats. Central or peripheral administration of a fluorophore-labeled GLP-1R agonist, exendin-4, localizes within astrocytes and neurons in the nucleus tractus solitarius (NTS), a hindbrain nucleus critical for energy balance control. This effect is mediated by GLP-1R, as the uptake of systemically administered fluorophore-tagged exendin-4 was blocked by central pretreatment with the competitive GLP-1R antagonist exendin-(9–39). Ex vivo analyses show prolonged exendin-4-induced activation (live cell calcium signaling) of NTS astrocytes and neurons; these effects are also attenuated by exendin-(9–39), indicating mediation by the GLP-1R. In vitro analyses show that the application of GLP-1R agonists increases cAMP levels in astrocytes. Immunohistochemical analyses reveal that endogenous GLP-1 axons form close synaptic apposition with NTS astrocytes. Finally, pharmacological inhibition of NTS astrocytes attenuates the anorectic and body weight-suppressive effects of intra-NTS GLP-1R activation. Collectively, data demonstrate a role for NTS astrocytic GLP-1R signaling in energy balance control
CANDELS Multi-wavelength Catalogs: Source Detection and Photometry in the GOODS-South Field
We present a UV-to-mid infrared multi-wavelength catalog in the
CANDELS/GOODS-S field, combining the newly obtained CANDELS HST/WFC3 F105W,
F125W, and F160W data with existing public data. The catalog is based on source
detection in the WFC3 F160W band. The F160W mosaic includes the data from
CANDELS deep and wide observations as well as previous ERS and HUDF09 programs.
The mosaic reaches a 5 limiting depth (within an aperture of radius
0.17 arcsec) of 27.4, 28.2, and 29.7 AB for CANDELS wide, deep, and HUDF
regions, respectively. The catalog contains 34930 sources with the
representative 50% completeness reaching 25.9, 26.6, and 28.1 AB in the F160W
band for the three regions. In addition to WFC3 bands, the catalog also
includes data from UV (U-band from both CTIO/MOSAIC and VLT/VIMOS), optical
(HST/ACS F435W, F606W, F775W, F814W, and F850LP), and infrared (HST/WFC3 F098M,
VLT/ISAAC Ks, VLT/HAWK-I Ks, and Spitzer/IRAC 3.6, 4.5, 5.8, 8.0 m)
observations. The catalog is validated via stellar colors, comparison with
other published catalogs, zeropoint offsets determined from the best-fit
templates of the spectral energy distribution of spectroscopically observed
objects, and the accuracy of photometric redshifts. The catalog is able to
detect unreddened star-forming (passive) galaxies with stellar mass of
10^{10}M_\odot at a 50% completeness level to z3.4 (2.8), 4.6 (3.2), and
7.0 (4.2) in the three regions. As an example of application, the catalog is
used to select both star-forming and passive galaxies at z2--4 via the
Balmer break. It is also used to study the color--magnitude diagram of galaxies
at 0<z<4.Comment: The full resolution article is now published in ApJS (2013, 207, 24).
22 pages, 21 figures, and 5 tables. The catalogue is available on the CANDELS
website: http://candels.ucolick.org/data_access/GOODS-S.html MAST:
http://archive.stsci.edu/prepds/candels and Rainbow Database:
https://arcoiris.ucolick.org/Rainbow_navigator_public and
https://rainbowx.fis.ucm.es/Rainbow_navigator_publi
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