95 research outputs found
Simultaneous Magneto-Optical Trapping of Two Lithium Isotopes
We confine 4 10^8 fermionic 6Li atoms simultaneously with 9 10^9 bosonic 7Li
atoms in a magneto-optical trap based on an all-semiconductor laser system. We
optimize the two-isotope sample for sympathetic evaporative cooling. This is an
essential step towards the production of a quantum-degenerate gas of fermionic
lithium atoms.Comment: 4 pages, 3 figure
Evolution of the Color-Magnitude Relation in Galaxy Clusters at z ~1 from the ACS Intermediate Redshift Cluster Survey
We apply detailed observations of the Color-Magnitude Relation (CMR) with the
ACS/HST to study galaxy evolution in eight clusters at z~1. The early-type red
sequence is well defined and elliptical and lenticular galaxies lie on similar
CMRs. We analyze CMR parameters as a function of redshift, galaxy properties
and cluster mass. For bright galaxies (M_B < -21mag), the CMR scatter of the
elliptical population in cluster cores is smaller than that of the S0
population, although the two become similar at faint magnitudes. While the
bright S0 population consistently shows larger scatter than the ellipticals,
the scatter of the latter increases in the peripheral cluster regions. If we
interpret these results as due to age differences, bright elliptical galaxies
in cluster cores are on average older than S0 galaxies and peripheral
elliptical galaxies (by about 0.5Gyr). CMR zero point, slope, and scatter in
the (U-B)_z=0 rest-frame show no significant evolution out to redshift z~1.3
nor significant dependence on cluster mass. Two of our clusters display CMR
zero points that are redder (by ~2sigma) than the average (U-B)_z=0 of our
sample. We also analyze the fraction of morphological early-type and late-type
galaxies on the red sequence. We find that, while in the majority of the
clusters most (80% to 90%) of the CMR population is composed of early-type
galaxies, in the highest redshift, low mass cluster of our sample, the CMR
late-type/early-type fractions are similar (~50%), with most of the late-type
population composed of galaxies classified as S0/a. This trend is not
correlated with the cluster's X-ray luminosity, nor with its velocity
dispersion, and could be a real evolution with redshift.Comment: ApJ, in press, 27 pages, 22 figure
Early-type galaxies at z = 1.3. I. The Lynx supercluster: cluster and groups at z=1.3. Morphology and color-magnitude relation
We confirm the detection of 3 groups in the Lynx supercluster, at z~1.3, and
give their redshifts and masses. We study the properties of the group galaxies
as compared to the central clusters, RXJ0849+4452 and RXJ0848+4453, selecting
89 galaxies in the clusters and 74 galaxies in the groups. We morphologically
classify galaxies by visual inspection, noting that our early-type galaxy (ETG)
sample would have been contaminated at the 30% -40% level by simple automated
classification methods (e.g. based on Sersic index). In luminosity selected
samples, both clusters and groups show high fractions of Sa galaxies. The ETG
fractions never rise above ~50% in the clusters, which is low compared to the
fractions observed in clusters at z~1. However, ETG plus Sa fractions are
similar to those observed for ETGs in clusters at z~1. Bulge-dominated galaxies
visually classified as Sas might also be ETGs with tidal features or merger
remnants. They are mainly red and passive, and span a large range in
luminosity. Their star formation seems to have been quenched before
experiencing a morphological transformation. Because their fraction is smaller
at lower redshifts, they might be the spiral population that evolves into ETGs.
For mass-selected samples, the ETG fraction show no significant evolution with
respect to local clusters, suggesting that morphological transformations occur
at lower masses and densities. The ETG mass-size relation shows evolution
towards smaller sizes at higher redshift in both clusters and groups, while the
late-type mass-size relation matches that observed locally. The group ETG red
sequence shows lower zero points and larger scatters than in clusters, both
expected to be an indication of a younger galaxy population. The estimated age
difference is small when compared to the difference in age at different galaxy
masses.Comment: ApJ, submitted - referee report answered - iterating with the refere
Randomized Noninferiority Trial of Telephone vs In-Person Genetic Counseling for Hereditary Breast and Ovarian Cancer: A 12-Month Follow-Up
Background: Telephone delivery of genetic counseling is an alternative to in-person genetic counseling because it may extend the reach of genetic counseling. Previous reports have established the noninferiority of telephone counseling on short-term psychosocial and decision-making outcomes. Here we examine the long-term impact of telephone counseling (TC) vs inperson counseling (usual care [UC]).
Methods: We recruited high-risk women for a noninferiority trial comparing TC with UC. Of 1057 potentially eligible women, 669 were randomly assigned to TC (n = 335) or UC (n = 334), and 512 completed the 12-month follow-up. Primary outcomes were patient-reported satisfaction with genetic testing decision, distress, and quality of life. Secondary outcomes were uptake of cancer risk management strategies.
Results: TC was noninferior to UC on all primary outcomes. Satisfaction with decision (d = 0.13, lower bound of 97.5% confidence interval [CI] = -0.34) did not cross its one-point noninferiority limit, cancer-specific distress (d = -2.10, upper bound of 97.5% CI = -0.07) did not cross its four-point noninferiority limit, and genetic testing distress (d = -0.27, upper bound of 97.5% CI = 1.46), physical function (d = 0.44, lower bound of 97.5% CI = -0.91) and mental function (d = -0.04, lower bound of 97.5% CI = -1.44) did not cross their 2.5-point noninferiority limit. Bivariate analyses showed no differences in risk-reducing mastectomy or oophorectomy across groups; however, when combined, TC had significantly more risk-reducing surgeries than UC (17.8% vs 10.5%; chi(2) = 4.43, P = .04).
Conclusions: Findings support telephone delivery of genetic counseling to extend the accessibility of this service without long-termadverse outcomes.This study was supported by grants (R01 CA108933 and P30 CA051008) from the National Cancer Institute and by the Jess and Mildred Fisher Center for Hereditary Cancer and Clinical Genomics Research.Peer Reviewe
Spatial distribution characteristics and optimized reconstruction analysis of China’s rural settlements during the process of rapid urbanization
The Luminosity Functions of the Galaxy Cluster MS1054-0321 at z=0.83 based on ACS Photometry
We present new measurements of the galaxy luminosity function (LF) and its
dependence on local galaxy density, color, morphology, and clustocentric radius
for the massive z=0.83 cluster MS1054-0321. Our analyses are based on imaging
performed with the ACS onboard the HST in the F606W, F775W and F850LP passbands
and extensive spectroscopic data obtained with the Keck LRIS. Our main results
are based on a spectroscopically selected sample of 143 cluster members with
morphological classifications derived from the ACS observations. Our three
primary findings are (1) the faint-end slope of the LF is steepest in the
bluest filter, (2) the LF in the inner part of the cluster (or highest density
regions) has a flatter faint-end slope, and (3) the fraction of early-type
galaxies is higher at the bright end of the LF, and gradually decreases toward
fainter magnitudes. These characteristics are consistent with those in local
galaxy clusters, indicating that, at least in massive clusters, the common
characteristics of cluster LFs are established at z=0.83. We also find a 2sigma
deficit of intrinsically faint, red galaxies (i-z>0.5, Mi>-19) in this cluster.
This trend may suggest that faint, red galaxies (which are common in z<0.1 rich
clusters) have not yet been created in this cluster at z=0.83. The
giant-to-dwarf ratio in MS1054-0321 starts to increase inwards of the virial
radius or when Sigma>30 Mpc^-2, coinciding with the environment where the
galaxy star formation rate and the morphology-density relation start to appear.
(abridged)Comment: ApJ in press, references update
Association of Variants in the SPTLC1 Gene With Juvenile Amyotrophic Lateral Sclerosis
Importance: Juvenile amyotrophic lateral sclerosis (ALS) is a rare form of ALS characterized by age of symptom onset less than 25 years and a variable presentation.Objective: To identify the genetic variants associated with juvenile ALS.Design, Setting, and Participants: In this multicenter family-based genetic study, trio whole-exome sequencing was performed to identify the disease-associated gene in a case series of unrelated patients diagnosed with juvenile ALS and severe growth retardation. The patients and their family members were enrolled at academic hospitals and a government research facility between March 1, 2016, and March 13, 2020, and were observed until October 1, 2020. Whole-exome sequencing was also performed in a series of patients with juvenile ALS. A total of 66 patients with juvenile ALS and 6258 adult patients with ALS participated in the study. Patients were selected for the study based on their diagnosis, and all eligible participants were enrolled in the study. None of the participants had a family history of neurological disorders, suggesting de novo variants as the underlying genetic mechanism.Main Outcomes and Measures: De novo variants present only in the index case and not in unaffected family members.Results: Trio whole-exome sequencing was performed in 3 patients diagnosed with juvenile ALS and their parents. An additional 63 patients with juvenile ALS and 6258 adult patients with ALS were subsequently screened for variants in the SPTLC1 gene. De novo variants in SPTLC1 (p.Ala20Ser in 2 patients and p.Ser331Tyr in 1 patient) were identified in 3 unrelated patients diagnosed with juvenile ALS and failure to thrive. A fourth variant (p.Leu39del) was identified in a patient with juvenile ALS where parental DNA was unavailable. Variants in this gene have been previously shown to be associated with autosomal-dominant hereditary sensory autonomic neuropathy, type 1A, by disrupting an essential enzyme complex in the sphingolipid synthesis pathway.Conclusions and Relevance: These data broaden the phenotype associated with SPTLC1 and suggest that patients presenting with juvenile ALS should be screened for variants in this gene.</p
Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector
A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements
The genetic architecture of the human cerebral cortex
The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder
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