1,423 research outputs found
Rethinking transparency and accountability in medicines regulation in the United Kingdom
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The Utilization of Hiring High-Profile Head Football Coaches to Market the Athletic Department and Boost Fan Attendance at NCAA Division I Institutions
Robo-AO Kepler Survey IV: the effect of nearby stars on 3857 planetary candidate systems
We present the overall statistical results from the Robo-AO Kepler planetary
candidate survey, comprising of 3857 high-angular resolution observations of
planetary candidate systems with Robo-AO, an automated laser adaptive optics
system. These observations reveal previously unknown nearby stars blended with
the planetary candidate host star which alter the derived planetary radii or
may be the source of an astrophysical false positive transit signal. In the
first three papers in the survey, we detected 440 nearby stars around 3313
planetary candidate host stars. In this paper, we present observations of 532
planetary candidate host stars, detecting 94 companions around 88 stars; 84 of
these companions have not previously been observed in high-resolution. We also
report 50 more-widely-separated companions near 715 targets previously observed
by Robo-AO. We derive corrected planetary radius estimates for the 814
planetary candidates in systems with a detected nearby star. If planetary
candidates are equally likely to orbit the primary or secondary star, the
radius estimates for planetary candidates in systems with likely bound nearby
stars increase by a factor of 1.54, on average. We find that 35
previously-believed rocky planet candidates are likely not rocky due to the
presence of nearby stars. From the combined data sets from the complete Robo-AO
KOI survey, we find that 14.5\pm0.5% of planetary candidate hosts have a nearby
star with 4", while 1.2% have two nearby stars and 0.08% have three. We find
that 16% of Earth-sized, 13% of Neptune-sized, 14% of Saturn-sized, and 19% of
Jupiter-sized planet candidates have detected nearby stars.Comment: Accepted to the Astronomical Journa
Probability of Physical Association of 104 Blended Companions to Kepler Objects of Interest Using Visible and Near-Infrared Adaptive Optics Photometry
We determine probabilities of physical association for stars in blended Kepler Objects of Interest (KOIs), and find that 14.5%_(-3.4%)^(+3.8%) of companions within ~ 4" are consistent with being physically unassociated with their primary. This produces a better understanding of potential false positives in the Kepler catalog and will guide models of planet formation in binary systems. Physical association is determined through two methods of calculating multi-band photometric parallax using visible and near-infrared adaptive optics observations of 84 KOI systems with 104 contaminating companions within ~ 4". We find no evidence that KOI companions with separations of less than 1" are more likely to be physically associated than KOI companions generally. We also reinterpret transit depths for 94 planet candidates, and calculate that 2.6% ± 0.4% of transits have R > 15R_⊕, which is consistent with prior modeling work
Robo-AO Kepler Survey V: The effect of physically associated stellar companions on planetary systems
The Kepler light curves used to detect thousands of planetary candidates are
susceptible to dilution due to blending with previously unknown nearby stars.
With the automated laser adaptive optics instrument, Robo-AO, we have observed
620 nearby stars around 3857 planetary candidates host stars. Many of the
nearby stars, however, are not bound to the KOI. In this paper, we quantify the
association probability between each KOI and detected nearby stars through
several methods. Galactic stellar models and the observed stellar density are
used to estimate the number and properties of unbound stars. We estimate the
spectral type and distance to 145 KOIs with nearby stars using multi-band
observations from Robo-AO and Keck-AO. We find most nearby stars within 1" of a
Kepler planetary candidate are likely bound, in agreement with past studies. We
use likely bound stars as well as the precise stellar parameters from the
California Kepler Survey to search for correlations between stellar binarity
and planetary properties. No significant difference between the binarity
fraction of single and multiple planet systems is found, and planet hosting
stars follow similar binarity trends as field stars, many of which likely host
their own non-aligned planets. We find that hot Jupiters are ~4x more likely
than other planets to reside in a binary star system. We correct the radius
estimates of the planet candidates in characterized systems and find that for
likely bound systems, the estimated planetary candidate radii will increase on
average by a factor of 1.77, if either star is equally likely to host the
planet. We find that the planetary radius gap is robust to the impact of
dilution, and find an intriguing 95%-confidence discrepancy between the radius
distribution of small planets in single and binary systems.Comment: 19 pages, 12 figures, submitted to AAS Journal
DockoMatic - Automated Ligand Creation and Docking
Background: The application of computational modeling to rationally design drugs and characterize macro biomolecular receptors has proven increasingly useful due to the accessibility of computing clusters and clouds. AutoDock is a well-known and powerful software program used to model ligand to receptor binding interactions. In its current version, AutoDock requires significant amounts of user time to setup and run jobs, and collect results. This paper presents DockoMatic, a user friendly Graphical User Interface (GUI) application that eases and automates the creation and management of AutoDock jobs for high throughput screening of ligand to receptor interactions.
Results: DockoMatic allows the user to invoke and manage AutoDock jobs on a single computer or cluster, including jobs for evaluating secondary ligand interactions. It also automates the process of collecting, summarizing, and viewing results. In addition, DockoMatic automates creation of peptide ligand .pdb files from strings of single-letter amino acid abbreviations.
Conclusions: DockoMatic significantly reduces the complexity of managing multiple AutoDock jobs by facilitating ligand and AutoDock job creation and management
The Robo-AO KOI survey: laser adaptive optics imaging of every Kepler exoplanet candidate
The Robo-AO Kepler Planetary Candidate Survey is observing every Kepler planet candidate host star (KOI) with laser adaptive optics imaging to hunt for blended nearby stars which may be physically associated companions. With the unparalleled efficiency provided by the first fully robotic adaptive optics system, we perform the critical search for nearby stars (0.15" to 4.0" separation with contrasts up to 6 magnitudes) that dilute the observed planetary transit signal, contributing to inaccurate planetary characteristics or astrophysical false positives. We present 3313 high resolution observations of Kepler planetary hosts from 2012-2015, discovering 479 nearby stars. We measure an overall nearby star probability rate of 14.5±0.8%. With this large data set, we are uniquely able to explore broad correlations between multiple star systems and the properties of the planets which they host, providing insight into the formation and evolution of planetary systems in our galaxy. Several KOIs of particular interest will be discussed, including possible quadruple star systems hosting planets and updated properties for possible rocky planets orbiting with in their star's habitable zone
The cytoplasmic domain of the Plasmodium falciparum ligand EBA-175 is essential for invasion but not protein trafficking
The invasion of host cells by the malaria parasite Plasmodium falciparum requires specific protein–protein interactions between parasite and host receptors and an intracellular translocation machinery to power the process. The transmembrane erythrocyte binding protein-175 (EBA-175) and thrombospondin-related anonymous protein (TRAP) play central roles in this process. EBA-175 binds to glycophorin A on human erythrocytes during the invasion process, linking the parasite to the surface of the host cell. In this report, we show that the cytoplasmic domain of EBA-175 encodes crucial information for its role in merozoite invasion, and that trafficking of this protein is independent of this domain. Further, we show that the cytoplasmic domain of TRAP, a protein that is not expressed in merozoites but is essential for invasion of liver cells by the sporozoite stage, can substitute for the cytoplasmic domain of EBA-175. These results show that the parasite uses the same components of its cellular machinery for invasion regardless of the host cell type and invasive form
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