35 research outputs found
Simultaneous Exoplanet Characterization and deep wide-field imaging with a diffractive pupil telescope
High-precision astrometry can identify exoplanets and measure their orbits
and masses, while coronagraphic imaging enables detailed characterization of
their physical properties and atmospheric compositions through spectroscopy. In
a previous paper, we showed that a diffractive pupil telescope (DPT) in space
can enable sub-microarcsecond accuracy astrometric measurements from wide-field
images by creating faint but sharp diffraction spikes around the bright target
star. The DPT allows simultaneous astrometric measurement and coronagraphic
imaging, and we discuss and quantify in this paper the scientific benefits of
this combination for exoplanet science investigations: identification of
exoplanets with increased sensitivity and robustness, and ability to measure
planetary masses to high accuracy. We show how using both measurements to
identify planets and measure their masses offers greater sensitivity and
provides more reliable measurements than possible with separate missions, and
therefore results in a large gain in mission efficiency. The combined
measurements reliably identify potentially habitable planets in multiple
systems with a few observations, while astrometry or imaging alone would
require many measurements over a long time baseline. In addition, the combined
measurement allows direct determination of stellar masses to percent-level
accuracy, using planets as test particles. We also show that the DPT maintains
the full sensitivity of the telescope for deep wide-field imaging, and is
therefore compatible with simultaneous scientific observations unrelated to
exoplanets. We conclude that astrometry, coronagraphy, and deep wide-field
imaging can be performed simultaneously on a single telescope without
significant negative impact on the performance of any of the three techniques.Comment: 15 pages, 6 figures. This second paper, following the paper
describing the diffractive pupil telescope (DPT) astrometric technique, shows
how simultaneous astrometry and coronagraphy observations, enabled by the DPT
concept, constrain the orbital parameters and mass of exoplanet
Temporal Associations between Psychological and Physical Intimate Partner Violence: A Cross-Lag Analysis
The present study examined the relationship between psychological and physical forms of intimate partner violence (IPV) across four waves of data during the developmental period of young adulthood. The links from early psychological aggression to later physical aggression and from early physical aggression to later psychological aggression across waves were tested while controlling for their cross-time stabilities and concurrent associations. IPV data were collected annually from 434 young adult respondents involved in a romantic relationship at least once during the respective years from the ages of 22-25. On average, participants provided IPV data for three out of the four years covered by the study (M = 2.82; SD = 1.14). Results of a cross-lagged SEM model indicated significant cross-time stabilities as well as significant, positive concurrent associations for both forms of aggression. Most important to this study were the findings that, controlling for these stabilities and concurrent associations, early psychological aggression was a consistent positive predictor of later physical aggression across waves whereas the opposite direction from early physical aggression to later psychological aggression was either non-significant or significant and negative
Systems Engineering on the James Webb Space Telescope
The James Web Space Telescope (JWST) is a large, infrared-optimized space telescope scheduled for launch in 2014. System-level verification of critical performance requirements will rely on integrated observatory models that predict the wavefront error accurately enough to verify that allocated top-level wavefront error of 150 nm root-mean-squared (rms) through to the wave-front sensor focal plane is met. This paper describes the systems engineering approach used on the JWST through the detailed design phase
Survival probability of mutually killing Brownian motions and the O'Connell process
Recently O'Connell introduced an interacting diffusive particle system in
order to study a directed polymer model in 1+1 dimensions. The infinitesimal
generator of the process is a harmonic transform of the quantum Toda-lattice
Hamiltonian by the Whittaker function. As a physical interpretation of this
construction, we show that the O'Connell process without drift is realized as a
system of mutually killing Brownian motions conditioned that all particles
survive forever. When the characteristic length of interaction killing other
particles goes to zero, the process is reduced to the noncolliding Brownian
motion (the Dyson model).Comment: v2: AMS-LaTeX, 20 pages, 2 figures, minor corrections made for
publication in J. Stat. Phy
The Science Performance of JWST as Characterized in Commissioning
This paper characterizes the actual science performance of the James Webb
Space Telescope (JWST), as determined from the six month commissioning period.
We summarize the performance of the spacecraft, telescope, science instruments,
and ground system, with an emphasis on differences from pre-launch
expectations. Commissioning has made clear that JWST is fully capable of
achieving the discoveries for which it was built. Moreover, almost across the
board, the science performance of JWST is better than expected; in most cases,
JWST will go deeper faster than expected. The telescope and instrument suite
have demonstrated the sensitivity, stability, image quality, and spectral range
that are necessary to transform our understanding of the cosmos through
observations spanning from near-earth asteroids to the most distant galaxies.Comment: 5th version as accepted to PASP; 31 pages, 18 figures;
https://iopscience.iop.org/article/10.1088/1538-3873/acb29
Rural Cooperatives Magazine
Features- Ownership succession crucial for rural america; Groomed for success; Expanding your customer base; Climbing the hill; Agriculture of the Middle: Opportunity for co-ops; Tomato co-ops help craft better food safety standards; Sailing turbulent seas; Co-op ideas can help educatio
Recommended from our members
Rural Cooperatives Magazine
Features- Ownership succession crucial for rural america; Groomed for success; Expanding your customer base; Climbing the hill; Agriculture of the Middle: Opportunity for co-ops; Tomato co-ops help craft better food safety standards; Sailing turbulent seas; Co-op ideas can help educatio
High rates of regional failure in squamous cell carcinoma of the hard palate and maxillary alveolus
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Building Block-Based Binding Predictions for DNA-Encoded Libraries.
DNA-encoded libraries (DELs) provide the means to make and screen millions of diverse compounds against a target of interest in a single experiment. However, despite producing large volumes of binding data at a relatively low cost, the DEL selection process is susceptible to noise, necessitating computational follow-up to increase signal-to-noise ratios. In this work, we present a set of informatics tools to employ data from prior DEL screen(s) to gain information about which building blocks are most likely to be productive when designing new DELs for the same target. We demonstrate that similar building blocks have similar probabilities of forming compounds that bind. We then build a model from the inference that the combined behavior of individual building blocks is predictive of whether an overall compound binds. We illustrate our approach on a set of three-cycle OpenDEL libraries screened against soluble epoxide hydrolase (sEH) and report performance of more than an order of magnitude greater than random guessing on a holdout set, demonstrating that our model can serve as a baseline for comparison against other machine learning models on DEL data. Lastly, we provide a discussion on how we believe this informatics workflow could be applied to benefit researchers in their specific DEL campaigns