140 research outputs found
Pulsation period variations in the RRc Lyrae star KIC 5520878
Learned et. al. proposed that a sufficiently advanced extra-terrestrial
civilization may tickle Cepheid and RR Lyrae variable stars with a neutrino
beam at the right time, thus causing them to trigger early and jogging the
otherwise very regular phase of their expansion and contraction. This would
turn these stars into beacons to transmit information throughout the galaxy and
beyond. The idea is to search for signs of phase modulation (in the regime of
short pulse duration) and patterns, which could be indicative of intentional,
omnidirectional signaling.
We have performed such a search among variable stars using photometric data
from the Kepler space telescope. In the RRc Lyrae star KIC 5520878, we have
found two such regimes of long and short pulse durations. The sequence of
period lengths, expressed as time series data, is strongly auto correlated,
with correlation coefficients of prime numbers being significantly higher
(\%). Our analysis of this candidate star shows that the prime number
oddity originates from two simultaneous pulsation periods and is likely of
natural origin.
Simple physical models elucidate the frequency content and asymmetries of the
KIC 5520878 light curve.
Despite this SETI null result, we encourage testing other archival and future
time-series photometry for signs of modulated stars. This can be done as a
by-product to the standard analysis, and even partly automated.Comment: Accepted for publication in ApJ. 49 pages, 16 figure
Fingerprints of biocomplexity: Taxon‐specific growth of phytoplankton in relation to environmental factors
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110012/1/lno2004494part21446.pd
Perceived Stress After Acute Myocardial Infarction: A Comparison Between Young and Middle-Aged Women Versus Men
Objective: The aim of the study was to examine how psychological stress changes over time in young and middle-aged patients after experiencing an acute myocardial infarction (AMI) and whether these changes differ between men and women.
Methods: We analyzed data obtained from 2358 women and 1151 men aged 18 to 55 years hospitalized for AMI. Psychological stress was measured using the 14-item Perceived Stress Scale (PSS-14) at initial hospitalization and at 1 month and 12 months after AMI. We used linear mixed-effects models to examine changes in PSS-14 scores over time and sex differences in these changes, while adjusting for patient characteristics and accounting for correlation among repeated observations within patients.
Results: Overall, patients' perceived stress decreased over time, especially during the first month after AMI. Women had higher levels of perceived stress than men throughout the 12-month period (difference in PSS-14 score = 3.63, 95% confidence interval = 3.08 to 4.18, p < .001), but they did not differ in how stress changed over time. Adjustment for patient characteristics did not alter the overall pattern of sex difference in changes of perceived stress over time other than attenuating the magnitude of sex difference in PSS-14 score (difference between women and men = 1.74, 95% confidence interval = 1.32 to 2.16, p < .001). The magnitude of sex differences in perceived stress was similar in patients with versus without post-AMI angina, even though patients with angina experienced less improvement in PSS-14 score than those without angina.
Conclusions: In young and middle-aged patients with AMI, women reported higher levels of perceived stress than men throughout the first 12 months of recovery. However, women and men had a similar pattern in how perceived stress changed over time
GAMA: towards a physical understanding of galaxy formation
The Galaxy And Mass Assembly (GAMA) project is the latest in a tradition of
large galaxy redshift surveys, and is now underway on the 3.9m Anglo-Australian
Telescope at Siding Spring Observatory. GAMA is designed to map extragalactic
structures on scales of 1kpc - 1Mpc in complete detail to a redshift of z~0.2,
and to trace the distribution of luminous galaxies out to z~0.5. The principal
science aim is to test the standard hierarchical structure formation paradigm
of Cold Dark Matter (CDM) on scales of galaxy groups, pairs, discs, bulges and
bars. We will measure (1) the Dark Matter Halo Mass Function (as inferred from
galaxy group velocity dispersions); (2) baryonic processes, such as star
formation and galaxy formation efficiency (as derived from Galaxy Stellar Mass
Functions); and (3) the evolution of galaxy merger rates (via galaxy close
pairs and galaxy asymmetries). Additionally, GAMA will form the central part of
a new galaxy database, which aims to contain 275,000 galaxies with
multi-wavelength coverage from coordinated observations with the latest
international ground- and space-based facilities: GALEX, VST, VISTA, WISE,
HERSCHEL, GMRT and ASKAP. Together, these data will provide increased depth
(over 2 magnitudes), doubled spatial resolution (0.7"), and significantly
extended wavelength coverage (UV through Far-IR to radio) over the main SDSS
spectroscopic survey for five regions, each of around 50 deg^2. This database
will permit detailed investigations of the structural, chemical, and dynamical
properties of all galaxy types, across all environments, and over a 5 billion
year timeline.Comment: GAMA overview which appeared in the October 2009 issue of Astronomy &
Geophysics, ref: Astron.Geophys. 50 (2009) 5.1
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Biological, clinical and population relevance of 95 loci for blood lipids.
Plasma concentrations of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglycerides are among the most important risk factors for coronary artery disease (CAD) and are targets for therapeutic intervention. We screened the genome for common variants associated with plasma lipids in >100,000 individuals of European ancestry. Here we report 95 significantly associated loci (P < 5 x 10(-8)), with 59 showing genome-wide significant association with lipid traits for the first time. The newly reported associations include single nucleotide polymorphisms (SNPs) near known lipid regulators (for example, CYP7A1, NPC1L1 and SCARB1) as well as in scores of loci not previously implicated in lipoprotein metabolism. The 95 loci contribute not only to normal variation in lipid traits but also to extreme lipid phenotypes and have an impact on lipid traits in three non-European populations (East Asians, South Asians and African Americans). Our results identify several novel loci associated with plasma lipids that are also associated with CAD. Finally, we validated three of the novel genes-GALNT2, PPP1R3B and TTC39B-with experiments in mouse models. Taken together, our findings provide the foundation to develop a broader biological understanding of lipoprotein metabolism and to identify new therapeutic opportunities for the prevention of CAD
Complete Genome Sequences of Chop, DelRio, and GrandSlam, Three Gordonia Phages Isolated from Soil in Central Arkansas
Chop, DelRio, and GrandSlam are phage with a Siphoviridae morphotype isolated from soil in Arkansas using the host Gordonia terrae 3612. All three are temperate, and their genomes share at least 96% nucleotide identity. These phage are assigned to cluster DI based on gene content similarity to other sequenced actinobacteriophage
The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey
The Sloan Digital Sky Survey III (SDSS-III) presents the first spectroscopic
data from the Baryon Oscillation Spectroscopic Survey (BOSS). This ninth data
release (DR9) of the SDSS project includes 535,995 new galaxy spectra (median
z=0.52), 102,100 new quasar spectra (median z=2.32), and 90,897 new stellar
spectra, along with the data presented in previous data releases. These spectra
were obtained with the new BOSS spectrograph and were taken between 2009
December and 2011 July. In addition, the stellar parameters pipeline, which
determines radial velocities, surface temperatures, surface gravities, and
metallicities of stars, has been updated and refined with improvements in
temperature estimates for stars with T_eff<5000 K and in metallicity estimates
for stars with [Fe/H]>-0.5. DR9 includes new stellar parameters for all stars
presented in DR8, including stars from SDSS-I and II, as well as those observed
as part of the SDSS-III Sloan Extension for Galactic Understanding and
Exploration-2 (SEGUE-2).
The astrometry error introduced in the DR8 imaging catalogs has been
corrected in the DR9 data products. The next data release for SDSS-III will be
in Summer 2013, which will present the first data from the Apache Point
Observatory Galactic Evolution Experiment (APOGEE) along with another year of
data from BOSS, followed by the final SDSS-III data release in December 2014.Comment: 9 figures; 2 tables. Submitted to ApJS. DR9 is available at
http://www.sdss3.org/dr
Space Radiation Alters Genotype–Phenotype Correlations in Fear Learning and Memory Tests
Behavioral and cognitive traits have a genetic component even though contributions from individual genes and genomic loci are in many cases modest. Changes in the environment can alter genotype–phenotype relationships. Space travel, which includes exposure to ionizing radiation, constitutes environmental challenges and is expected to induce not only dramatic behavioral and cognitive changes but also has the potential to induce physical DNA damage. In this study, we utilized a genetically heterogeneous mouse model, dense genotype data, and shifting environmental challenges, including ionizing radiation exposure, to explore and quantify the size and stability of the genetic component of fear learning and memory-related measures. Exposure to ionizing radiation and other external stressors altered the genotype–phenotype correlations, although different behavioral and cognitive measures were affected to different extents. Utilizing an integrative genomic approach, we identified pathways and functional ontology categories associated with these behavioral and cognitive measures
The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III
The Sloan Digital Sky Survey (SDSS) started a new phase in August 2008, with
new instrumentation and new surveys focused on Galactic structure and chemical
evolution, measurements of the baryon oscillation feature in the clustering of
galaxies and the quasar Ly alpha forest, and a radial velocity search for
planets around ~8000 stars. This paper describes the first data release of
SDSS-III (and the eighth counting from the beginning of the SDSS). The release
includes five-band imaging of roughly 5200 deg^2 in the Southern Galactic Cap,
bringing the total footprint of the SDSS imaging to 14,555 deg^2, or over a
third of the Celestial Sphere. All the imaging data have been reprocessed with
an improved sky-subtraction algorithm and a final, self-consistent photometric
recalibration and flat-field determination. This release also includes all data
from the second phase of the Sloan Extension for Galactic Understanding and
Evolution (SEGUE-2), consisting of spectroscopy of approximately 118,000 stars
at both high and low Galactic latitudes. All the more than half a million
stellar spectra obtained with the SDSS spectrograph have been reprocessed
through an improved stellar parameters pipeline, which has better determination
of metallicity for high metallicity stars.Comment: Astrophysical Journal Supplements, in press (minor updates from
submitted version
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