116 research outputs found
From Courtroom to Classroom: Operationalizing Adequacy in Funding Teaching and Learning
A quality, standards-based reform would provide a framework and system of accountability that elevates the most possible number of our students to acquisition of an academic foundation and allows students the greatest number of future academic options and careers
RELICS: High-Resolution Constraints on the Inner Mass Distribution of the z=0.83 Merging Cluster RXJ0152.7-1357 from strong lensing
Strong gravitational lensing (SL) is a powerful means to map the distribution
of dark matter. In this work, we perform a SL analysis of the prominent X-ray
cluster RXJ0152.7-1357 (z=0.83, also known as CL 0152.7-1357) in \textit{Hubble
Space Telescope} images, taken in the framework of the Reionization Lensing
Cluster Survey (RELICS). On top of a previously known galaxy multiply
imaged by RXJ0152.7-1357, for which we identify an additional multiple image,
guided by a light-traces-mass approach we identify seven new sets of multiply
imaged background sources lensed by this cluster, spanning the redshift range
[1.79-3.93]. A total of 25 multiple images are seen over a small area of ~0.4
, allowing us to put relatively high-resolution constraints on the
inner matter distribution. Although modestly massive, the high degree of
substructure together with its very elongated shape make RXJ0152.7-1357 a very
efficient lens for its size. This cluster also comprises the third-largest
sample of z~6-7 candidates in the RELICS survey. Finally, we present a
comparison of our resulting mass distribution and magnification estimates with
those from a Lenstool model. These models are made publicly available through
the MAST archive.Comment: 15 Pages, 7 Figures, 4 Tables Accepted for publication in Ap
Evasion of anti-growth signaling: a key step in tumorigenesis and potential target for treatment and prophylaxis by natural compounds
The evasion of anti-growth signaling is an important characteristic of cancer cells. In order to continue to proliferate, cancer cells must somehow uncouple themselves from the many signals that exist to slow down cell growth. Here, we define the anti-growth signaling process, and review several important pathways involved in growth signaling: p53, phosphatase and tensin homolog (PTEN), retinoblastoma protein (Rb), Hippo, growth differentiation factor 15 (GDF15), AT-rich interactive domain 1A (ARID1A), Notch, insulin-like growth factor (IGF), and Krüppel-like factor 5 (KLF5) pathways. Aberrations in these processes in cancer cells involve mutations and thus the suppression of genes that prevent growth, as well as mutation and activation of genes involved in driving cell growth. Using these pathways as examples, we prioritize molecular targets that might be leveraged to promote anti-growth signaling in cancer cells. Interestingly, naturally-occurring phytochemicals found in human diets (either singly or as mixtures) may promote anti-growth signaling, and do so without the potentially adverse effects associated with synthetic chemicals. We review examples of naturally-occurring phytochemicals that may be applied to prevent cancer by antagonizing growth signaling, and propose one phytochemical for each pathway. These are: epigallocatechin-3-gallate (EGCG) for the Rb pathway, luteolin for p53, curcumin for PTEN, porphyrins for Hippo, genistein for GDF15, resveratrol for ARID1A, withaferin A for Notch and diguelin for the IGF1-receptor pathway. The coordination of anti-growth signaling and natural compound studies will provide insight into the future application of these compounds in the clinical setting
RELICS: Strong Lensing analysis of the galaxy clusters Abell S295, Abell 697, MACS J0025.4-1222, and MACS J0159.8-0849
We present a strong-lensing analysis of four massive galaxy clusters imaged
with the Hubble Space Telescope in the Reionization Lensing Cluster Survey. We
use a Light-Traces-Mass technique to uncover sets of multiply images and
constrain the mass distribution of the clusters. These mass models are the
first published for Abell S295 and MACS J0159.8-0849, and are improvements over
previous models for Abell 697 and MACS J0025.4-1222. Our analysis for MACS
J0025.4-1222 and Abell S295 shows a bimodal mass distribution supporting the
merger scenarios proposed for these clusters. The updated model for MACS
J0025.4-1222 suggests a substantially smaller critical area than previously
estimated. For MACS J0159.8-0849 and Abell 697 we find a single peak and
relatively regular morphology, revealing fairly relaxed clusters. Despite being
less prominent lenses, three of these clusters seem to have lensing strengths,
i.e. cumulative area above certain magnification, similar to the Hubble
Frontier Fields clusters (e.g., A() arcmin, A()
arcmin), which in part can be attributed to their merging
configurations. We make our lens models publicly available through the Mikulski
Archive for Space Telescopes. Finally, using Gemini-N/GMOS spectroscopic
observations we detect a single emission line from a high-redshift
galaxy candidate lensed by Abell 697. While we cannot rule
out a lower-redshift solution, we interpret the line as Ly at
, in agreement with its photometric redshift and dropout
nature. Within this scenario we measure a Ly rest-frame equivalent
width of \AA, and an observed Gaussian width of km/s.Comment: 23 pages, 16 figures; V2, accepted for publication in Ap
RELICS: A Very Large () Cluster Lens -- RXC J0032.1+1808
Extensive surveys with the \textit{Hubble Space Telescope} (HST) over the
past decade, targeting some of the most massive clusters in the sky, have
uncovered dozens of galaxy-cluster strong lenses. The massive cluster
strong-lens scale is typically \theta_{E}\sim10\arcsec to \sim30-35\arcsec,
with only a handful of clusters known with Einstein radii
\theta_{E}\sim40\arcsec or above (for , nominally). Here we
report another very large cluster lens, RXC J0032.1+1808 (), the
second richest cluster in the redMapper cluster catalog and the 85th most
massive cluster in the Planck Sunyaev-Zel'dovich catalog. With our
Light-Traces-Mass and fully parametric (dPIEeNFW) approaches, we construct
strong lensing models based on 18 multiple images of 5 background galaxies
newly identified in the \textit{Hubble} data mainly from the
\textit{Reionization Lensing Cluster Survey} (RELICS), in addition to a known
sextuply imaged system in this cluster. Furthermore, we compare these models to
Lenstool and GLAFIC models that were produced independently as part of the
RELICS program. All models reveal a large effective Einstein radius of
\theta_{E}\simeq40\arcsec (), owing to the obvious
concentration of substructures near the cluster center. Although RXC
J0032.1+1808 has a very large critical area and high lensing strength, only
three magnified high-redshift candidates are found within the field targeted by
RELICS. Nevertheless, we expect many more high-redshift candidates will be seen
in wider and deeper observations with \textit{Hubble} or \emph{JWST}. Finally,
the comparison between several algorithms demonstrates that the total error
budget is largely dominated by systematic uncertainties.Comment: 23 pages, accepted for publication in Ap
The Hobby–Eberly Telescope Dark Energy Experiment (HETDEX) Survey Design, Reductions, and Detections
We describe the survey design, calibration, commissioning, and emission-line detection algorithms for the Hobby–Eberly Telescope Dark Energy Experiment (HETDEX). The goal of HETDEX is to measure the redshifts of over a million Lyα emitting galaxies between 1.88 < z < 3.52, in a 540 deg2 area encompassing a comoving volume of 10.9 Gpc3. No preselection of targets is involved; instead the HETDEX measurements are accomplished via a spectroscopic survey using a suite of wide-field integral field units distributed over the focal plane of the telescope. This survey measures the Hubble expansion parameter and angular diameter distance, with a final expected accuracy of better than 1%. We detail the project’s observational strategy, reduction pipeline, source detection, and catalog generation, and present initial results for science verification in the Cosmological Evolution Survey, Extended Groth Strip, and Great Observatories Origins Deep Survey North fields. We demonstrate that our data reach the required specifications in throughput, astrometric accuracy, flux limit, and object detection, with the end products being a catalog of emission-line sources, their object classifications, and flux-calibrated spectra
3 Markets, Bureaucracies, and Clans The Nature of Organizations
E valuating organizations according to an efficiency criterion would make it possible to predict the form organizations will take under certain conditions. Organization theory has not developed such a criterion because it has lacked a conceptual scheme capable of describing organizational efficiency in sufficiently microsopic terms. The transactions cost approach provides such a framework because it allows us to identify the conditions which give rise to the costs of mediating exchanges between individuals: goal incongruence and performance ambiguity. Different combinations of these causes distinguish three basic mechanisms of mediation or control: markets, which are efficient when performance ambiguity is low and goal incongruence is high; bureaucracies, which are efficient when both goal incongruence and performance ambiguity are moderately high; and clans, which are efficient when goal incongruence is low and performance ambiguity is high
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