129 research outputs found
FIGS -- Faint Infrared Grism Survey: Description and Data Reduction
The Faint Infrared Grism Survey (FIGS) is a deep Hubble Space Telescope (HST)
WFC3/IR (Wide Field Camera 3 Infrared) slitless spectroscopic survey of four
deep fields. Two fields are located in the Great Observatories Origins Deep
Survey-North (GOODS-N) area and two fields are located in the Great
Observatories Origins Deep Survey-South (GOODS-S) area. One of the southern
fields selected is the Hubble Ultra Deep Field. Each of these four fields were
observed using the WFC3/G102 grism (0.8-1.15 continuous coverage)
with a total exposure time of 40 orbits (~ 100 kilo-seconds) per field. This
reaches a 3 sigma continuum depth of ~26 AB magnitudes and probes emission
lines to . This paper details the four
FIGS fields and the overall observational strategy of the project. A detailed
description of the Simulation Based Extraction (SBE) method used to extract and
combine over 10000 spectra of over 2000 distinct sources brighter than
m_F105W=26.5 mag is provided. High fidelity simulations of the observations is
shown to significantly improve the background subtraction process, the spectral
contamination estimates, and the final flux calibration. This allows for the
combination of multiple spectra to produce a final high quality, deep,
1D-spectra for each object in the survey.Comment: 21 Pages. 17 Figures. To appear in Ap
A New Era in Extragalactic Background Light Measurements: The Cosmic History of Accretion, Nucleosynthesis and Reionization
(Brief Summary) What is the total radiative content of the Universe since the
epoch of recombination? The extragalactic background light (EBL) spectrum
captures the redshifted energy released from the first stellar objects,
protogalaxies, and galaxies throughout cosmic history. Yet, we have not
determined the brightness of the extragalactic sky from UV/optical to
far-infrared wavelengths with sufficient accuracy to establish the radiative
content of the Universe to better than an order of magnitude. Among many
science topics, an accurate measurement of the EBL spectrum from optical to
far-IR wavelengths, will address: What is the total energy released by stellar
nucleosynthesis over cosmic history? Was significant energy released by
non-stellar processes? Is there a diffuse component to the EBL anywhere from
optical to sub-millimeter? When did first stars appear and how luminous was the
reionization epoch? Absolute optical to mid-IR EBL spectrum to an
astrophysically interesting accuracy can be established by wide field imagingat
a distance of 5 AU or above the ecliptic plane where the zodiacal foreground is
reduced by more than two orders of magnitude.Comment: 7 pages; Science White Paper for the US Astro 2010-2020 Decadal
Survey. If interested in further community-wide efforts on this topic please
contact the first autho
A Strong-Lensing Model for the WMDF JWST/GTO Very Rich Cluster Abell 1489
We present a first strong-lensing model for the galaxy cluster RM
J121218.5+273255.1 (; hereafter RMJ1212; also known as Abell 1489).
This cluster is amongst the top 0.1\% richest clusters in the redMaPPer
catalog; it is significantly detected in X-ray and through the
Sunyaev-Zel'dovich effect in ROSAT and \emph{Planck} data, respectively; and
its optical luminosity distribution implies a very large lens, following
mass-to-light scaling relations. Based on these properties it was chosen for
the Webb Medium Deep Fields (WMDF) JWST/GTO program. In preparation for this
program, RMJ1212 was recently imaged with GMOS on Gemini North and in seven
optical and near-infrared bands with the \emph{Hubble Space Telescope}. We use
these data to map the inner mass distribution of the cluster, uncovering
various sets of multiple images. We also search for high-redshift candidates in
the data, as well as for transient sources. We find over a dozen high-redshift
() candidates based on both photometric redshift and the dropout
technique. No prominent () transients were found in the data
between the two HST visits. Our lensing analysis reveals a relatively large
lens with an effective Einstein radius of
(), in broad agreement with the scaling-relation expectations. RMJ1212
demonstrates that powerful lensing clusters can be selected in a robust and
automated way following the light-traces-mass assumption.Comment: 17 pages, 6 figures, 2 tables; To be submitte
The Global Brain Health Survey: Development of a Multi-Language Survey of Public Views on Brain Health.
Background: Brain health is a multi-faceted concept used to describe brain physiology, cognitive function, mental health and well-being. Diseases of the brain account for one third of the global burden of disease and are becoming more prevalent as populations age. Diet, social interaction as well as physical and cognitive activity are lifestyle factors that can potentially influence facets of brain health. Yet, there is limited knowledge about the population's awareness of brain health and willingness to change lifestyle to maintain a healthy brain. This paper introduces the Global Brain Health Survey protocol, designed to assess people's perceptions of brain health and factors influencing brain health. Methods: The Global Brain Health Survey is an anonymous online questionnaire available in 14 languages to anyone above the age of 18 years. Questions focus on (1) willingness and motivation to maintain or improve brain health, (2) interest in learning more about individual brain health using standardized tests, and (3) interest in receiving individualized support to take care of own brain health. The survey questions were developed based on results from a qualitative interview study investigating brain health perceptions among participants in brain research studies. The survey includes 28 questions and takes 15-20 min to complete. Participants provide electronically informed consent prior to participation. The current survey wave was launched on June 4, 2019 and will close on August 31, 2020. We will provide descriptive statistics of samples distributions including analyses of differences as a function of age, gender, education, country of residence, and we will examine associations between items. The European Union funded Lifebrain project leads the survey in collaboration with national brain councils in Norway, Germany, and Belgium, Brain Foundations in the Netherlands and Sweden, the National University of Ostroh Academy and the Women's Brain Project. Discussion: Results from this survey will provide new insights in peoples' views on brain health, in particular, the extent to which the adoption of positive behaviors can be encouraged. The results will contribute to the development of policy recommendations for supporting population brain health, including measures tailored to individual needs, knowledge, motivations and life situations
Asymmetric thinning of the cerebral cortex across the adult lifespan is accelerated in Alzheimer’s disease
© 2021, The Author(s). Aging and Alzheimer’s disease (AD) are associated with progressive brain disorganization. Although structural asymmetry is an organizing feature of the cerebral cortex it is unknown whether continuous age- and AD-related cortical degradation alters cortical asymmetry. Here, in multiple longitudinal adult lifespan cohorts we show that higher-order cortical regions exhibiting pronounced asymmetry at age ~20 also show progressive asymmetry-loss across the adult lifespan. Hence, accelerated thinning of the (previously) thicker homotopic hemisphere is a feature of aging. This organizational principle showed high consistency across cohorts in the Lifebrain consortium, and both the topological patterns and temporal dynamics of asymmetry-loss were markedly similar across replicating samples. Asymmetry-change was further accelerated in AD. Results suggest a system-wide dedifferentiation of the adaptive asymmetric organization of heteromodal cortex in aging and AD
High-Redshift Galaxy Candidates at as Revealed by JWST Observations of WHL0137-08
JWST was designed to peer into the distant universe and study galaxies nearer
the beginning of time than previously. Here we report the discovery of 12
galaxy candidates observed 300-600 Myr after the Big Bang with photometric
redshifts between z ~ 8.5-13 measured using JWST NIRCam imaging of the galaxy
cluster WHL0137 observed in 8 filters spanning 0.8-5.0 m, plus 9 HST
filters spanning 0.4-1.7 m. Three of these candidates are gravitationally
lensed by the foreground galaxy cluster and have magnifications of . The remaining nine candidates are located in a second JWST NIRCam module,
centered ~29' from the cluster center, with expected magnifications of <~
1.1. Our sample of high-redshift candidates have observed F200W AB magnitudes
between 25.9 and 28.1 mag and intrinsic F200W AB magnitudes between 26.4 and
29.7 mag ( = -22.5 to -17). We find the stellar masses of these
galaxies are in the range = 8 - 9, and down to 7.5 for
the lensed galaxies. All are young with mass-weighted ages < 100 Myr, low dust
content < 0.15 mag, and high specific star formation rates sSFR ~10-50
Gyr for most. One z ~ 9 candidate is consistent with an age < 5 Myr and
a sSFR ~250 Gyr, as inferred from a strong F444W excess, implying
[OIII]+H-beta rest-frame equivalent width ~2000 Angstrom, although an older and
redder z~ 10 object is also allowed. Another z~9 candidate ID9356 is lensed
into an arc 2.6" long by the effects of strong gravitational lensing (~8),
and has at least two bright knots of unevenly distributed star formation. This
arc is the most spatially-resolved galaxy at z~9 known to date, revealing
structures ~30 pc across. Follow-up spectroscopy of WHL0137 with JWST/NIRSpec
is planned for later this year, which will validate some of these candidates
and study their physical properties in more detail.Comment: submitted to Ap
Large neutral amino acid supplementation exerts its effect through three synergistic mechanisms:Proof of principle in phenylketonuria mice
Phenylketonuria (PKU) was the first disorder in which severe neurocognitive dysfunction could be prevented by dietary treatment. However, despite this effect, neuropsychological outcome in PKU still remains suboptimal and the phenylalanine-restricted diet is very demanding. To improve neuropsychological outcome and relieve the dietary restrictions for PKU patients, supplementation of large neutral amino acids (LNAA) is suggested as alternative treatment strategy that might correct all brain biochemical disturbances caused by high blood phenylalanine, and thereby improve neurocognitive functioning.As a proof-of-principle, this study aimed to investigate all hypothesized biochemical treatment objectives of LNAA supplementation (normalizing brain phenylalanine, non-phenylalanine LNAA, and monoaminergic neurotransmitter concentrations) in PKU mice.C57Bl/6 Pah-enu2 (PKU) mice and wild-type mice received a LNAA supplemented diet, an isonitrogenic/isocaloric high-protein control diet, or normal chow. After six weeks of dietary treatment, blood and brain amino acid and monoaminergic neurotransmitter concentrations were assessed.In PKU mice, the investigated LNAA supplementation regimen significantly reduced blood and brain phenylalanine concentrations by 33% and 26%, respectively, compared to normal chow (p<0.01), while alleviating brain deficiencies of some but not all supplemented LNAA. Moreover, LNAA supplementation in PKU mice significantly increased brain serotonin and norepinephrine concentrations from 35% to 71% and from 57% to 86% of wild-type concentrations (p<0.01), respectively, but not brain dopamine concentrations (p = 0.307).This study shows that LNAA supplementation without dietary phenylalanine restriction in PKU mice improves brain biochemistry through all three hypothesized biochemical mechanisms. Thereby, these data provide proof-of-concept for LNAA supplementation as a valuable alternative dietary treatment strategy in PKU. Based on these results, LNAA treatment should be further optimized for clinical application with regard to the composition and dose of the LNAA supplement, taking into account all three working mechanisms of LNAA treatment
JWST reveals a possible galaxy merger in triply-lensed MACS0647JD
MACS0647JD is a triply-lensed galaxy originally discovered with
the Hubble Space Telescope. Here we report new JWST imaging, which clearly
resolves MACS0647JD as having two components that are either merging
galaxies or stellar complexes within a single galaxy. Both are very small, with
stellar masses and radii . The brighter
larger component "A" is intrinsically very blue (), likely due
to very recent star formation and no dust, and is spatially extended with an
effective radius . The smaller component "B" appears redder
(), likely because it is older () with mild dust
extinction (), and a smaller radius . We
identify galaxies with similar colors in a high-redshift simulation, finding
their star formation histories to be out of phase. With an estimated stellar
mass ratio of roughly 2:1 and physical projected separation ,
we may be witnessing a galaxy merger 400 million years after the Big Bang. We
also identify a candidate companion galaxy C away, likely
destined to merge with galaxies A and B. The combined light from galaxies A+B
is magnified by factors of 8, 5, and 2 in three lensed images JD1, 2, and
3 with F356W fluxes , , (AB mag 25.1, 25.6, 26.6).
MACS0647JD is significantly brighter than other galaxies recently discovered
at similar redshifts with JWST. Without magnification, it would have AB mag
27.3 (). With a high confidence level, we obtain a photometric
redshift of based on photometry measured in 6 NIRCam filters
spanning , out to rest-frame. JWST NIRSpec
observations planned for January 2023 will deliver a spectroscopic redshift and
a more detailed study of the physical properties of MACS0647JD.Comment: 27 pages, 14 figures, submitted to Natur
Organização do trabalho de enfermagem na Atenção Básica: uma questão para a saúde do trabalhador
Contains fulltext :
208073.pdf (publisher's version ) (Open Access
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