113 research outputs found
Developmental analyses of mouse embryos and adults using a non-overlapping tracing system for all three germ layers
Evidence for Spin–Orbit Alignment in the TRAPPIST-1 System
In an effort to measure the Rossiter–McLaughlin effect for the TRAPPIST-1 system, we performed high-resolution spectroscopy during transits of planets e, f, and b. The spectra were obtained with the InfraRed Doppler spectrograph on the Subaru 8.2 m telescope, and were supplemented with simultaneous photometry obtained with a 1 m telescope of the Las Cumbres Observatory Global Telescope. By analyzing the anomalous radial velocities, we found the projected stellar obliquity to be λ = 1 ± 28° under the assumption that the three planets have coplanar orbits, although we caution that the radial-velocity data show correlated noise of unknown origin. We also sought evidence for the expected deformations of the stellar absorption lines, and thereby detected the "Doppler shadow" of planet b with a false-alarm probability of 1.7%. The joint analysis of the observed residual cross-correlation map including the three transits gave λ = 19_(-15)^(+13)°. These results indicate that the the TRAPPIST-1 star is not strongly misaligned with the common orbital plane of the planets, although further observations are encouraged to verify this conclusion
Planet(esimal)s Around Stars with TESS (PAST) III: A Search for Triplet He I in the Atmospheres of Two 200 Myr-old Planets
We report a search for excess absorption in the 1083.2 nm line of ortho
(triplet) helium during transits of TOI-1807b and TOI-2076b, 1.25 and
2.5R planets on 0.55- and 10.4-day orbits around nearby
200~Myr-old K dwarf stars. We limit the equivalent width of any
transit-associated absorption to 4 and 8 mA, respectively. We limit the
escape of solar-composition atmospheres from TOI-1807b and TOI-2076b to
1 and 0.1M Gyr, respectively,
depending on wind temperature. The absence of a H/He signature for TOI-1807b is
consistent with a measurement of mass indicating a rocky body and the
prediction by a hydrodynamic model that any H-dominated atmosphere would be
unstable and already have been lost. Differential spectra obtained during the
transit of TOI-2076b contain a He I-like feature, but this closely resembles
the stellar line and extends beyond the transit interval. Until additional
transits are observed, we suspect this to be the result of variation in the
stellar He I line produced by rotation of active regions and/or flaring on the
young, active host star. Non-detection of escape could mean that TOI-2076b is
more massive than expected, the star is less EUV-luminous, the models
overestimate escape, or the planet has a H/He-poor atmosphere that is primarily
molecules such as HO. Photochemical models of planetary winds predict a
semi-major axis at which triplet He I observations are most sensitive to mass
loss: TOI-2076b orbits near this optimum. Future surveys could use a distance
criterion to increase the yield of detections.Comment: Accepted to MNRA
Multiplexed Molecular Profiling of Lung Cancer Using Pleural Effusion
Introduction:Pleural effusion is frequently observed in patients with advanced lung cancer. Although effusion can be obtained less invasively and repeatedly, its use in multiplexed molecular profiling has not been fully investigated.Methods:Between July 2011 and April 2013, pleural effusion samples were obtained from patients with lung cancer at Shizuoka Cancer Center. They were analyzed for EGFR, KRAS, BRAF, PIK3CA, NRAS, MEK1, AKT1, PTEN, and HER2 mutations, EGFR, MET, FGFR1, FGFR2, and PIK3CA amplifications, and ALK, ROS1, and RET fusion genes using pyrosequensing and/or capillary electrophoresis, quantitative reverse-transcriptase polymerase chain reaction, and reverse-transcriptase polymerase chain reaction, respectively.Results:One hundred and two samples from 84 patients were analyzed. Adenocarcinoma was the most common histological subtype (82%). Genetic abnormalities were detected in 42% of patients. The most common abnormality was EGFR mutation (29%), followed by EML4-ALK rearrangement (5%), KRAS mutation, and EGFR amplification (4%, each). Concordance rates between pleural effusion and matched formalin-fixed, paraffin-embedded samples were 88%. Among 11 patients who provided samples at multiple time points, changes in molecular profile over the course of treatment were observed in five patients.Conclusions:The use of pleural effusion for multiplexed molecular testing and real-time monitoring in lung cancer was demonstrated
Limits on the Spin-Orbit Angle and Atmospheric Escape for the 22 Myr-old Planet AU Mic b
We obtained spectra of the pre-main sequence star AU Microscopii during a
transit of its Neptune-sized planet to investigate its orbit and atmosphere. We
used the high-dispersion near-infrared spectrograph IRD on the Subaru telescope
to detect the Doppler "shadow" from the planet and constrain the projected
stellar obliquity. Modeling of the observed planetary Doppler shadow suggests a
spin-orbit alignment of the system ( degrees), but
additional observations are needed to confirm this finding. We use both the IRD
data and spectra obtained with NIRSPEC on Keck-II to search for absorption in
the 1083 nm line of metastable triplet He I by the planet's atmosphere and
place an upper limit for the equivalent width of 3.7 m\AA at 99
confidence. With this limit and a Parker wind model we constrain the escape
rate from the atmosphere to Gyr, comparable to
the rates predicted by an XUV energy-limited escape calculation and
hydrodynamic models, but refinement of the planet mass is needed for rigorous
tests.Comment: 10 pages, 5 figures, accepted for publication in ApJ Letter
Absence of extended atmospheres in low-mass star radius-gap planets GJ 9827 b, GJ 9827 d and TOI-1235 b
\textit{Kepler} showed a paucity of planets with radii of 1.5 - 2 around solar mass stars but this radius-gap has not been well
studied for low-mass star planets. Energy-driven escape models like
photoevaporation and core-powered mass-loss predict opposing transition regimes
between rocky and non-rocky planets when compared to models depicting planets
forming in gas-poor environments. Here we present transit observations of three
super-Earth sized planets in the radius-gap around low-mass stars using
high-dispersion InfraRed Doppler (IRD) spectrograph on the Subaru 8.2m
telescope. The planets GJ 9827 b and d orbit around a K6V star and TOI-1235 b
orbits a M0.5 star. We limit any planet-related absorption in the 1083.3 nm
lines of triplet He I by placing an upper-limit on the equivalent width of
14.71 m{\AA}, 18.39 m{\AA}, and 1.44 m{\AA}, for GJ 9827 b (99% confidence), GJ
9827 d (99% confidence) and TOI-1235 b (95% confidence) respectively. Using a
Parker wind model, we cap the mass-loss at 0.25
Gyr and 0.2 Gyr for GJ 9827 b and d,
respectively (99% confidence), and 0.05 Gyr for
TOI-1235 b (95\% confidence) for a representative wind temperature of 5000 K.
Our observed results for the three planets are more consistent with the
predictions from photoevaporation and/or core-powered mass-loss models than the
gas-poor formation models. However, more planets in the radius-gap regime
around the low-mass stars are needed to robustly predict the atmospheric
evolution in planets around low-mass stars.Comment: Accepted for MNRAS. 12 pages, 15 figure
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