2,439 research outputs found
Synthetic Galaxy Images and Spectra from the Illustris Simulation
We present our methods for generating a catalog of 7,000 synthetic images and
40,000 integrated spectra of redshift z = 0 galaxies from the Illustris
Simulation. The mock data products are produced by using stellar population
synthesis models to assign spectral energy distributions (SED) to each star
particle in the galaxies. The resulting synthetic images and integrated SEDs
therefore properly reflect the spatial distribution, stellar metallicity
distribution, and star formation history of the galaxies. From the synthetic
data products it is possible to produce monochromatic or color-composite
images, perform SED fitting, classify morphology, determine galaxy structural
properties, and evaluate the impacts of galaxy viewing angle. The main
contribution of this paper is to describe the production, format, and
composition of the image catalog that makes up the Illustris Simulation
Obsevatory. As a demonstration of this resource, we derive galactic stellar
mass estimates by applying the SED fitting code FAST to the synthetic galaxy
products, and compare the derived stellar masses against the true stellar
masses from the simulation. We find from this idealized experiment that
systematic biases exist in the photometrically derived stellar mass values that
can be reduced by using a fixed metallicity in conjunction with a minimum
galaxy age restriction.Comment: 21 pages, 17 figures, submitted to MNRAS. Comments welcom
Onset of experimental severe cardiac fibrosis is mediated by overexpression of angiotensin-converting enzyme 2
Angiotensin-converting enzyme (ACE) 2 is a recently identified homologue of ACE. There is great interest in the therapeutic benefit for ACE2 overexpression in the heart. However, the role of ACE2 in the regulation of cardiac structure and function, as well as maintenance of systemic blood pressure, remains poorly understood. In cell culture, ACE2 overexpression led to markedly increased myocyte volume, assessed in primary rabbit myocytes. To assess ACE2 function in vivo, we used a recombinant adeno-associated virus 6 delivery system to provide 11-week overexpression of ACE2 in the myocardium of stroke-prone spontaneously hypertensive rats. ACE2, as well as the ACE inhibitor enalapril, significantly reduced systolic blood pressure. However, in the heart, ACE2 overexpression resulted in cardiac fibrosis, as assessed by histological analysis with concomitant deficits in ejection fraction and fractional shortening measured by echocardiography. Furthermore, global gene expression profiling demonstrated the activation of profibrotic pathways in the heart mediated by ACE2 gene delivery. This study demonstrates that sustained overexpression of ACE2 in the heart in vivo leads to the onset of severe fibrosis
Galaxy morphology and star formation in the Illustris Simulation at
We study how optical galaxy morphology depends on mass and star formation rate (SFR) in the Illustris Simulation. To do so, we measure automated galaxy structures in 10 808 simulated galaxies at z = 0 with stellar masses 10[superscript 9.7] < M*/Mȯ < 10[superscript12.3]. We add observational realism to idealized synthetic images and measure non-parametric statistics in rest-frame optical and near-IR images from four directions. We find that Illustris creates a morphologically diverse galaxy population, occupying the observed bulge strength locus and reproducing median morphology trends versus stellar mass, SFR, and compactness. Morphology correlates realistically with rotation, following classification schemes put forth by kinematic surveys. Type fractions as a function of environment agree roughly with data. These results imply that connections among mass, star formation, and galaxy structure arise naturally from models matching global star formation and halo occupation functions when simulated with accurate methods. This raises a question of how to construct experiments on galaxy surveys to better distinguish between models. We predict that at fixed halo mass near 10[superscript 12] Mȯ, disc-dominated galaxies have higher stellar mass than bulge-dominated ones, a possible consequence of the Illustris feedback model. While Illustris galaxies at M* ∼ 10[superscript 11] Mȯ have a reasonable size distribution, those at M* ∼ 10[superscript 10] Mȯ have half-light radii larger than observed by a factor of 2. Furthermore, at M* ∼ 10[superscript 10.5]–10[superscript 11] Mȯ, a relevant fraction of Illustris galaxies have distinct ‘ring-like’ features, such that the bright pixels have an unusually wide spatial extent
The Lantern Vol. 3, No. 2, March 1935
• Puppets of Propaganda • Reluctance • Reflections From My Diary • Reverie • Bash Turner Enters the Limelight • The College Students\u27 Obligation • The Schwenkfelders • Love\u27s Desire • Verse • On the Squirt of a Grapefruit • Pioneers! • Whither Fraternities? • Mary Peters: A Book Review • Different as Night and Day • Ode to an Alley Cathttps://digitalcommons.ursinus.edu/lantern/1005/thumbnail.jp
Microbiota Modulate Behavioral and Physiological Abnormalities Associated with Neurodevelopmental Disorders
Neurodevelopmental disorders, including autism spectrum disorder (ASD), are defined by core behavioral impairments; however, subsets of individuals display a spectrum of gastrointestinal (GI) abnormalities. We demonstrate GI barrier defects and microbiota alterations in the maternal immune activation (MIA) mouse model that is known to display features of ASD. Oral treatment of MIA offspring with the human commensal Bacteroides fragilis corrects gut permeability, alters microbial composition, and ameliorates defects in communicative, stereotypic, anxiety-like and sensorimotor behaviors. MIA offspring display an altered serum metabolomic profile, and B. fragilis modulates levels of several metabolites. Treating naive mice with a metabolite that is increased by MIA and restored by B. fragilis causes certain behavioral abnormalities, suggesting that gut bacterial effects on the host metabolome impact behavior. Taken together, these findings support a gut-microbiome-brain connection in a mouse model of ASD and identify a potential probiotic therapy for GI and particular behavioral symptoms in human neurodevelopmental disorders
C5 Palsy After Cervical Spine Surgery: A Multicenter Retrospective Review of 59 Cases.
STUDY DESIGN: A multicenter, retrospective review of C5 palsy after cervical spine surgery.
OBJECTIVE: Postoperative C5 palsy is a known complication of cervical decompressive spinal surgery. The goal of this study was to review the incidence, patient characteristics, and outcome of C5 palsy in patients undergoing cervical spine surgery.
METHODS: We conducted a multicenter, retrospective review of 13 946 patients across 21 centers who received cervical spine surgery (levels C2 to C7) between January 1, 2005, and December 31, 2011, inclusive. P values were calculated using 2-sample t test for continuous variables and χ(2) tests or Fisher exact tests for categorical variables.
RESULTS: Of the 13 946 cases reviewed, 59 patients experienced a postoperative C5 palsy. The incidence rate across the 21 sites ranged from 0% to 2.5%. At most recent follow-up, 32 patients reported complete resolution of symptoms (54.2%), 15 had symptoms resolve with residual effects (25.4%), 10 patients did not recover (17.0%), and 2 were lost to follow-up (3.4%).
CONCLUSION: C5 palsy occurred in all surgical approaches and across a variety of diagnoses. The majority of patients had full recovery or recovery with residual effects. This study represents the largest series of North American patients reviewed to date
Teleost Growth Factor Independence (Gfi) Genes Differentially Regulate Successive Waves of Hematopoiesis
Growth Factor Independence (Gfi) transcription factors play essential roles in hematopoiesis, differentially activating and repressing transcriptional programs required for hematopoietic stem/progenitor cell (HSPC) development and lineage specification. In mammals, Gfi1a regulates hematopoietic stem cells (HSC), myeloid and lymphoid populations, while its paralog, Gfi1b, regulates HSC, megakaryocyte and erythroid development. In zebrafish, gfi1aa is essential for primitive hematopoiesis; however, little is known about the role of gfi1aa in definitive hematopoiesis or about additional gfi factors in zebrafish. Here, we report the isolation and characterization of an additional hematopoietic gfi factor, gfi1b. We show that gfi1aa and gfi1b are expressed in the primitive and definitive sites of hematopoiesis in zebrafish. Our functional analyses demonstrate that gfi1aa and gfi1b have distinct roles in regulating primitive and definitive hematopoietic progenitors, respectively. Loss of gfi1aa silences markers of early primitive progenitors, scl and gata1. Conversely, loss of gfi1b silences runx-1, c-myb, ikaros and cd41, indicating that gfi1b is required for definitive hematopoiesis. We determine the epistatic relationships between the gfi factors and key hematopoietic transcription factors, demonstrating that gfi1aa and gfi1b join lmo2, scl, runx-1 and c-myb as critical regulators of teleost HSPC. Our studies establish a comparative paradigm for the regulation of hematopoietic lineages by gfi transcription factors.Stem Cell and Regenerative Biolog
Vulnerable warriors: the atmospheric marketing of military and policing equipment before and after 9/11
In this article, we analyse changes in the circulation of advertisements of policing products at security expos between 1995 and 2013. While the initial aim of the research was to evidence shifts in terrorist frames in the marketing of policing equipment before and after 9/11, our findings instead suggested that what we are seeing is the rise of marketing to police as “vulnerable warriors”, law enforcement officers in need of military weapons both for their offensive capabilities and for the protection they can offer to a police force that is always under threat
Stable fiber-illumination for extremely precise radial velocities with NEID
NEID is a high-resolution red-optical precision radial velocity (RV)
spectrograph recently commissioned at the WIYN 3.5 m telescope at Kitt Peak
National Observatory, Arizona, USA. NEID has an extremely stable environmental
control system, and spans a wavelength range of 380 to 930 nm with two
observing modes: a High Resolution (HR) mode at R 112,000 for maximum RV
precision, and a High Efficiency (HE) mode at R 72,000 for faint
targets. In this manuscript we present a detailed description of the components
of NEID's optical fiber feed, which include the instrument, exposure meter,
calibration system, and telescope fibers. Many parts of the optical fiber feed
can lead to uncalibratable RV errors, which cannot be corrected for using a
stable wavelength reference source. We show how these errors directly cascade
down to performance requirements on the fiber feed and the scrambling system.
We detail the design, assembly, and testing of each component. Designed and
built from the bottom-up with a single-visit instrument precision requirement
of 27 , close attention was paid to the error contribution
from each NEID subsystem. Finally, we include the lab and on-sky tests
performed during instrument commissioning to test the illumination stability,
and discuss the path to achieving the instrumental stability required to search
for a true Earth twin around a Solar-type star.Comment: Accepted in A
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