2,018 research outputs found
The MASSIVE Survey - I. A Volume-Limited Integral-Field Spectroscopic Study of the Most Massive Early-Type Galaxies within 108 Mpc
Massive early-type galaxies represent the modern-day remnants of the earliest
major star formation episodes in the history of the universe. These galaxies
are central to our understanding of the evolution of cosmic structure, stellar
populations, and supermassive black holes, but the details of their complex
formation histories remain uncertain. To address this situation, we have
initiated the MASSIVE Survey, a volume-limited, multi-wavelength,
integral-field spectroscopic (IFS) and photometric survey of the structure and
dynamics of the ~100 most massive early-type galaxies within a distance of 108
Mpc. This survey probes a stellar mass range M* > 10^{11.5} Msun and diverse
galaxy environments that have not been systematically studied to date. Our
wide-field IFS data cover about two effective radii of individual galaxies, and
for a subset of them, we are acquiring additional IFS observations on
sub-arcsecond scales with adaptive optics. We are also acquiring deep K-band
imaging to trace the extended halos of the galaxies and measure accurate total
magnitudes. Dynamical orbit modeling of the combined data will allow us to
simultaneously determine the stellar, black hole, and dark matter halo masses.
The primary goals of the project are to constrain the black hole scaling
relations at high masses, investigate systematically the stellar initial mass
function and dark matter distribution in massive galaxies, and probe the
late-time assembly of ellipticals through stellar population and kinematical
gradients. In this paper, we describe the MASSIVE sample selection, discuss the
distinct demographics and structural and environmental properties of the
selected galaxies, and provide an overview of our basic observational program,
science goals and early survey results.Comment: 19 pages, 14 figures. ApJ (2014) vol. 795, in pres
The MASSIVE Survey II: Stellar Population Trends Out to Large Radius in Massive Early Type Galaxies
We examine stellar population gradients in ~100 massive early type galaxies
spanning 180 < sigma* < 370 km/s and M_K of -22.5 to -26.5 mag, observed as
part of the MASSIVE survey (Ma et al. 2014). Using integral-field spectroscopy
from the Mitchell Spectrograph on the 2.7m telescope at McDonald Observatory,
we create stacked spectra as a function of radius for galaxies binned by their
stellar velocity dispersion, stellar mass, and group richness. With excellent
sampling at the highest stellar mass, we examine radial trends in stellar
population properties extending to beyond twice the effective radius (~2.5
R_e). Specifically, we examine trends in age, metallicity, and abundance ratios
of Mg, C, N, and Ca, and discuss the implications for star formation histories
and elemental yields. At a fixed physical radius of 3-6 kpc (the likely size of
the galaxy cores formed at high redshift) stellar age and [alpha/Fe] increase
with increasing sigma* and depend only weakly on stellar mass, as we might
expect if denser galaxies form their central cores earlier and faster. If we
instead focus on 1-1.5 R_e, the trends in abundance and abundance ratio are
washed out, as might be expected if the stars at large radius were accreted by
smaller galaxies. Finally, we show that when controlling for \sigmastar, there
are only very subtle differences in stellar population properties or gradients
as a function of group richness; even at large radius internal properties
matter more than environment in determining star formation history.Comment: 17 pages, 9 figures, accepted by ApJ; resubmitted with updated
reference
Preplanned Studies: Orofacial Clefts in High Prevalence Area of Birth Defects ā Five Counties, Shanxi Province, China, 2000ā2020
What is already known on this topic?: The prevalence of structural birth defects, especially neural tube defects, decreased after national folic acid (FA) supplementation initiation. /
What is added by this report?: The prevalence of orofacial clefts (OFCs) in five counties of Shanxi Province in northern China, including most subtypes except cleft palate, showed a downward trend in the past two decades. In this study, pre-perinatal prevalence increased due to earlier detection. /
What are the implications for public health practice?: Periconceptional supplementation with FA may contribute to the decline in OFCs prevalence, while the effect on the OFCs subtype needs further investigation. Continuing to advocate for earlier supplementation (3 months before conception) and increased supplementation frequency (daily consumption) could promote further reduction in the prevalence of OFCs. Specific surveillance of this effect in the era of universal three-child policy is warranted
Changes in PPARĪ“ Protein Content following Acute Aerobic Exercise in Human Vastus Lateralis Muscle.
PPARĪ“ is a transcription factor which functions in the regulation of lipid and glucose metabolism, and may be implicated as a therapeutic target for several metabolic diseases. Exercise training has previously been shown to increase PPARĪ“ protein content, but the response of PPARĪ“ to acute exercise is not yet understood. PURPOSE: To explore changes in PPARĪ“ protein content following an acute bout of aerobic exercise in untrained obese adults. METHODS: 8 men and 4 women participated in the study. Subjectsā mean age, weight, VO2MAX (Bruce treadmill GXT), and body composition (DEXA) were 44 yr, 93.2 kg, 28.2 mL/kg/min, and 40.5% body fat, respectively. Subjects were asked to refrain from exercise for 1 week prior to the experiment and to maintain normal dietary habits during the study. Muscle biopsies were obtained from the vastus lateralis 3 days prior to acute exercise and again 24 hours after exercise. Subjects were exercised on a motorized treadmill at 70% VO2MAX for a target duration of 400kcal energy expenditure during the exercise session. PPARĪ“ protein content in biopsied tissue was determined by Western blot analysis. Data were analyzed by repeated measures ANOVA and expressed as means Ā± standard error. RESULTS: PPARĪ“ content was enhanced 24 hours following acute exercise in previously untrained, obese adults (unexercised 1.54Ā±0.38 vs. exercised 2.30Ā±0.39 arbitrary units, P\u3c0.05). Gel mobility shift indicated no difference in activity of PPARĪ“ (phosphorylated: total) following exercise (unexercised 0.36Ā±0.03 vs. exercised 0.34Ā±0.04). CONCLUSION: Our study shows that PPARĪ“ expression is enhanced in untrained, obese adults following a single bout of aerobic exercise with no relative change in phosphorylation of PPARĪ“. These data indicate that acute exercise plays a role in the expression of PPARĪ“. Funding for this research was provided by HydroWorx International, Inc., the Sydney & J.L. Huffines Institute for Sports Medicine and Human Performance at Texas A&M University and The Texas Chapter of The American College of Sports Medicin
Near Infrared Spectra and Intrinsic Luminosities of Candidate Type II Quasars at 2 < z < 3.4
We present JHK near-infrared (NIR) spectroscopy of 25 candidate Type II
quasars selected from the Sloan Digital Sky Survey, using Triplespec on the
Apache Point Observatory 3.5m telescope, FIRE at the Magellan/Baade 6.5m
telescope, and GNIRS on Gemini. At redshifts of 2 < z < 3.4, our NIR spectra
probe the rest-frame optical region of these targets, which were initially
selected to have strong lines of CIV and Ly alpha, with FWHM<2000 km/s from the
SDSS pipeline. We use the [OIII]5007 line shape as a model for the narrow line
region emission, and find that \halpha\ consistently requires a broad component
with FWHMs ranging from 1000 to 7500 km/s. Interestingly, the CIV lines also
require broad bases, but with considerably narrower widths of 1000 to 4500
km/s. Estimating the extinction using the Balmer decrement and also the
relationship in lower-z quasars between rest equivalent width and luminosity in
the [OIII] line, we find typical A_V values of 0-2 mag, which naturally explain
the attenuated CIV lines relative to Halpha. We propose that our targets are
moderately obscured quasars. We also describe one unusual object with three
distinct velocity peaks in its [OIII] spectrum.Comment: Accepted for publication in ApJ, 18 pages, 14 figure
Aquatic Treadmill Training Reduces Blood Pressure Reactivity to Acute Graded Exercise in Previously Sedentary Adults
Endurance exercise may reduce blood pressure and improve vasodilatory capacity thereby blunting the hypertensive response to stress. To test the efficacy of a novel model of low-impact endurance training, the aquatic-based treadmill (ATM), to improve blood pressure parameters, we recruited 60 sedentary adults and randomized to 12-weeks of either ATM (n = 36 [19 men, 17 women] , 41Ā±2 yr, 173.58 Ā±1.58cm, 93.19 Ā±3.15kg) or land-based treadmill (LTM, n = 24 [11 men, 13 women], 42 Ā±2yr, 170.39 Ā±1.94cm, 88.14 Ā±3.6kg) training; 3sessionsĀ·wk-1, progressing to 500 kcalĀ·session-1, 85% VO2max. The maximal Bruce treadmill test protocol was performed before and after training with blood pressures measured prior to, at the end of each stage, and for 5 minutes following exercise testing. Twelve subjects (5 ATM, 7 LTM) volunteered for biopsies of the vastus lateralis before and after training, and muscle samples were assessed for eNOS content. Blood pressure data were analyzed using group by training ANCOVA repeated across training, Ī± = 0.05. Data obtained from muscle sample analysis were analyzed using group by training ANOVA repeated across training Ī± = 0.05. Training reduced systolic blood pressure (9- 18.2mmHg), diastolic blood pressure (3.2-8.1 mmHg), mean arterial pressure (4.8-8.3mmHg), pulse pressure (7.5-15mmHg), and rate pressure product (1.8-3.9 bpmĀ·mm HgĀ·103) during exercise stress and recovery in the ATM group, but not in the LTM group. Additionally, the ATM group, but not the LTM group, displayed a 31% increase in skeletal muscle eNOS content following training. Both groups improved VO2max (+3.6mL O2Ā·kg-1Ā·min-1), but resting blood pressure was not changed following training. These data support the use of ATM training as a novel therapeutic modality to combat hypertension
Candidate Type II Quasars at 2 < z < 4.3 in the Sloan Digital Sky Survey III
At low redshifts, dust-obscured quasars often have strong yet narrow
permitted lines in the rest-frame optical and ultraviolet, excited by the
central active nucleus, earning the designation Type II quasars. We present a
sample of 145 candidate Type II quasars at redshifts between 2 and 4.3,
encompassing the epoch at which quasar activity peaked in the universe. These
objects, selected from the quasar sample of the Baryon Oscillation
Spectroscopic Survey of the Sloan Digital Sky Survey III, are characterized by
weak continuum in the rest-frame ultraviolet (typical continuum magnitude of i
\approx 22) and strong lines of CIV and Ly \alpha, with Full Width at Half
Maximum less than 2000 kms-1. The continuum magnitudes correspond to an
absolute magnitude of -23 or brighter at redshift 3, too bright to be due
exclusively to the host galaxies of these objects. Roughly one third of the
objects are detected in the shorter-wavelength bands of the WISE survey; the
spectral energy distributions (SEDs) of these objects appear to be intermediate
between classic Type I and Type II quasars seen at lower redshift. Five objects
are detected at rest frame 6\mu m by Spitzer, implying bolometric luminosities
of several times 10^46 erg s-1. We have obtained polarization measurements for
two objects; they are roughly 3% polarized. We suggest that these objects are
luminous quasars, with modest dust extinction (A_V ~ 0.5 mag), whose
ultraviolet continuum also includes a substantial scattering contribution.
Alternatively, the line of sight to the central engines of these objects may be
partially obscured by optically thick material.Comment: 26 pages, 13 figures, 10 tables, 4 machine readable tables. Accepted
for publication in MNRA
Arene oxidation with malonoyl peroxides
Malonoyl peroxide 7, prepared in a single step from the commercially available diacid, is an effective reagent for the
oxidation of aromatics. Reaction of an arene with peroxide 7 at room temperature leads to the corresponding protected phenol
which can be unmasked by aminolysis. An ionic mechanism consistent with the experimental findings and supported by isotopic
labeling, Hammett analysis, EPR investigations and reactivity profile studies is proposed
Vangl2 disruption alters the biomechanics of late spinal neurulation leading to spina bifida in mouse embryos
peer-reviewedHuman mutations in the planar cell polarity component VANGL2 are associated with the neural tube defect spina bifida. Homozygous Vangl2 mutation in mice prevents initiation of neural tube closure, precluding analysis of its subsequent roles in neurulation. Spinal neurulation involves rostral-to-caudal āzipperingā until completion of closure is imminent, when a caudal-to-rostral closure point, āClosure 5ā, arises at the caudal-most extremity of the posterior neuropore (PNP). Here, we used Grhl3Cre to delete Vangl2 in the surface ectoderm (SE) throughout neurulation and in an increasing proportion of PNP neuroepithelial cells at late neurulation stages. This deletion impaired PNP closure after the ā¼25-somite stage and resulted in caudal spina bifida in 67% of Grhl3Cre/+Vangl2Fl/Fl embryos. In the dorsal SE, Vangl2 deletion diminished rostrocaudal cell body orientation, but not directional polarisation of cell divisions. In the PNP, Vangl2 disruption diminished mediolateral polarisation of apical neuroepithelial F-actin profiles and resulted in eversion of the caudal PNP. This eversion prevented elevation of the caudal PNP neural folds, which in control embryos is associated with formation of Closure 5 around the 25-somite stage. Closure 5 formation in control embryos is associated with a reduction in mechanical stress withstood at the main zippering point, as inferred from the magnitude of neural fold separation following zippering point laser ablation. This stress accommodation did not happen in Vangl2-disrupted embryos. Thus, disruption of Vangl2-dependent planar-polarised processes in the PNP neuroepithelium and SE preclude zippering point biomechanical accommodation associated with Closure 5 formation at the completion of PNP closure
The MASSIVE Survey. VI. The spatial sistribution and kinematics of warm ionized gas in the most massive local early-type galaxies
We present the first systematic investigation of the existence, spatial distribution, and kinematics of warm ionized gas as traced by the [O ii] 3727 Ć
emission line in 74 of the most massive galaxies in the local universe. All of our galaxies have deep integral-field spectroscopy from the volume- and magnitude-limited MASSIVE survey of early-type galaxies with stellar mass (M K < ā25.3 mag) and distance D < 108 Mpc. Of the 74 galaxies in our sample, we detect warm ionized gas in 28, which yields a global detection fraction of 38 Ā± 6% down to a typical [O ii] equivalent width limit of 2 Ć
. MASSIVE fast rotators are more likely to have gas than MASSIVE slow rotators with detection fractions of 80 Ā± 10% and 28 Ā± 6%, respectively. The spatial extents span a wide range of radii (0.6ā18.2 kpc; 0.1ā4R e ), and the gas morphologies are diverse, with 17/28 ā 61 Ā± 9% being centrally concentrated, 8/28 ā 29 Ā± 9% exhibiting clear rotation out to several kiloparsecs, and 3/28 ā 11 Ā± 6% being extended but patchy. Three out of four fast rotators show kinematic alignment between the stars and gas, whereas the two slow rotators with robust kinematic measurements available exhibit kinematic misalignment. Our inferred warm ionized gas masses are roughly ~105 M ā. The emission line ratios and radial equivalent width profiles are generally consistent with excitation of the gas by the old underlying stellar population. We explore different gas origin scenarios for MASSIVE galaxies and find that a variety of physical processes are likely at play, including internal gas recycling, cooling out of the hot gaseous halo, and gas acquired via mergers
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