65 research outputs found
Induced earthquake families reveal distinctive evolutionary patterns near disposal wells
The timing of events in seismic sequences can provide insights into the physical processes controlling fault slip. In southern Kansas, the rate of earthquakes rose rapidly starting in 2013 following expansion of energy production into the area, demanding the disposal of large volumes of wastewater into deep wells. Seismicity catalogs that are complete to low magnitudes can provide insights into the physical processes that induce seismicity near wastewater disposal. We develop a catalog of over 130,000 earthquakes recorded in southern Kansas from midâMarch 2014 through December 2017 by applying a matched filter algorithm to an original catalog of 5,831 template earthquakes. Detections have nearly identical waveforms to their associated template event and represent slip on nearly coâlocated sections of a fault. We select template events with at least 100 associated detections and examine the characteristics of these prolific families of earthquakes. We find that families located close (<10 km) to areas with significant volumes of injected fluids have nearâPoissonian interevent times and the families remain active over longer durations. Families farther from highâvolume injection wells show strong clustering of interevent times and shorter sequence durations. We conclude that increasing pore fluid pressures from nearby disposal of large volumes of wastewater is the primary driver of these long duration episodes, with earthquakeâearthquake interactions driving sequences at greater distance from the wells
A Modular Strategy for Fully Conjugated DonorâAcceptor Block Copolymers
A novel strategy for the synthesis of fully conjugated donorâacceptor block copolymers, in a single reaction step employing Stille coupling polymerization of end-functional polythiophene and AA + BB monomers, is presented. The unique donorâacceptor structure of these block copolymers provides a rich self-assembly behavior, with the first example of a fully conjugated donorâacceptor block copolymer having two separate crystalline domains being obtained
Induced earthquake families reveal distinctive evolutionary patterns near disposal wells
The timing of events in seismic sequences can provide insights into the physical processes controlling fault slip. In southern Kansas, the rate of earthquakes rose rapidly starting in 2013 following expansion of energy production into the area, demanding the disposal of large volumes of wastewater into deep wells. Seismicity catalogs that are complete to low magnitudes can provide insights into the physical processes that induce seismicity near wastewater disposal. We develop a catalog of over 130,000 earthquakes recorded in southern Kansas from midâMarch 2014 through December 2017 by applying a matched filter algorithm to an original catalog of 5,831 template earthquakes. Detections have nearly identical waveforms to their associated template event and represent slip on nearly coâlocated sections of a fault. We select template events with at least 100 associated detections and examine the characteristics of these prolific families of earthquakes. We find that families located close (<10 km) to areas with significant volumes of injected fluids have nearâPoissonian interevent times and the families remain active over longer durations. Families farther from highâvolume injection wells show strong clustering of interevent times and shorter sequence durations. We conclude that increasing pore fluid pressures from nearby disposal of large volumes of wastewater is the primary driver of these long duration episodes, with earthquakeâearthquake interactions driving sequences at greater distance from the wells
A Modular Strategy for Fully Conjugated DonorâAcceptor Block Copolymers
A novel strategy for the synthesis of fully conjugated donorâacceptor block copolymers, in a single reaction step employing Stille coupling polymerization of end-functional polythiophene and AA + BB monomers, is presented. The unique donorâacceptor structure of these block copolymers provides a rich self-assembly behavior, with the first example of a fully conjugated donorâacceptor block copolymer having two separate crystalline domains being obtained
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An ANXA11 P93S variant dysregulates TDPâ43 and causes corticobasal syndrome
IntroductionVariants of uncertain significance (VUS) surged with affordable genetic testing, posing challenges for determining pathogenicity. We examine the pathogenicity of a novel VUS P93S in Annexin A11 (ANXA11) - an amyotrophic lateral sclerosis/frontotemporal dementia-associated gene - in a corticobasal syndrome kindred. Established ANXA11 mutations cause ANXA11 aggregation, altered lysosomal-RNA granule co-trafficking, and transactive response DNA binding protein of 43 kDa (TDP-43) mis-localization.MethodsWe described the clinical presentation and explored the phenotypic diversity of ANXA11 variants. P93S's effect on ANXA11 function and TDP-43 biology was characterized in induced pluripotent stem cell-derived neurons alongside multiomic neuronal and microglial profiling.ResultsANXA11 mutations were linked to corticobasal syndrome cases. P93S led to decreased lysosome colocalization, neuritic RNA, and nuclear TDP-43 with cryptic exon expression. Multiomic microglial signatures implicated immune dysregulation and interferon signaling pathways.DiscussionThis study establishes ANXA11 P93S pathogenicity, broadens the phenotypic spectrum of ANXA11 mutations, underscores neuronal and microglial dysfunction in ANXA11 pathophysiology, and demonstrates the potential of cellular models to determine variant pathogenicity.HighlightsANXA11 P93S is a pathogenic variant. Corticobasal syndrome is part of the ANXA11 phenotypic spectrum. Hybridization chain reaction fluorescence in situ hybridization (HCR FISH) is a new tool for the detection of cryptic exons due to TDP-43-related loss of splicing regulation. Microglial ANXA11 and related immune pathways are important drivers of disease. Cellular models are powerful tools for adjudicating variants of uncertain significance
Masses, radii, and orbits of small Kepler planets : The transition from gaseous to rocky planets
We report on the masses, sizes, and orbits of the planets orbiting 22 Kepler stars. There are 49 planet candidates around these stars, including 42 detected through transits and 7 revealed by precise Doppler measurements of the host stars. Based on an analysis of the Kepler brightness measurements, along with high-resolution imaging and spectroscopy, Doppler spectroscopy, and (for 11 stars) asteroseismology, we establish low false-positive probabilities (FPPs) for all of the transiting planets (41 of 42 have an FPP under 1%), and we constrain their sizes and masses. Most of the transiting planets are smaller than three times the size of Earth. For 16 planets, the Doppler signal was securely detected, providing a direct measurement of the planet's mass. For the other 26 planets we provide either marginal mass measurements or upper limits to their masses and densities; in many cases we can rule out a rocky composition. We identify six planets with densities above 5 g cm-3, suggesting a mostly rocky interior for them. Indeed, the only planets that are compatible with a purely rocky composition are smaller than 2 R â. Larger planets evidently contain a larger fraction of low-density material (H, He, and H2O).Peer reviewedFinal Accepted Versio
Kepler-21b: A 1.6REarth Planet Transiting the Bright Oscillating F Subgiant Star HD 179070
We present Kepler observations of the bright (V=8.3), oscillating star HD
179070. The observations show transit-like events which reveal that the star is
orbited every 2.8 days by a small, 1.6 R_Earth object. Seismic studies of HD
179070 using short cadence Kepler observations show that HD 179070 has a
frequencypower spectrum consistent with solar-like oscillations that are
acoustic p-modes. Asteroseismic analysis provides robust values for the mass
and radius of HD 179070, 1.34{\pm}0.06 M{\circ} and 1.86{\pm}0.04 R{\circ}
respectively, as well as yielding an age of 2.84{\pm}0.34 Gyr for this F5
subgiant. Together with ground-based follow-up observations, analysis of the
Kepler light curves and image data, and blend scenario models, we
conservatively show at the >99.7% confidence level (3{\sigma}) that the transit
event is caused by a 1.64{\pm}0.04 R_Earth exoplanet in a 2.785755{\pm}0.000032
day orbit. The exoplanet is only 0.04 AU away from the star and our
spectroscopic observations provide an upper limit to its mass of ~10 M_Earth
(2-{\sigma}). HD 179070 is the brightest exoplanet host star yet discovered by
Kepler.Comment: Accepted to Ap
KELT-21b: A Hot Jupiter Transiting the Rapidly Rotating Metal-poor Late-A Primary of a Likely Hierarchical Triple System
We present the discovery of KELT-21b, a hot Jupiter transiting the V = 10.5 A8V star HD 332124. The planet has an orbital period of P = 3.6127647 ± 0.0000033 days and a radius of 1.586-0.040+0.039 RJ. We set an upper limit on the planetary mass of at confidence. We confirmed the planetary nature of the transiting companion using this mass limit and Doppler tomographic observations to verify that the companion transits HD 332124. These data also demonstrate that the planetary orbit is well-aligned with the stellar spin, with a sky-projected spin-orbit misalignment of λ = -5.6-1.91.7. The star has Teff = 7598-8481 K, Mz.ast; = 1.458-0.028+0.029 Mâ, Rz.ast; = 1.638 ± 0.034 Râ and v sin Iâ = 146 km s-1, the highest projected rotation velocity of any star known to host a transiting hot Jupiter. The star also appears to be somewhat metal poor and α-enhanced, with [Fe/H] = -405-0.033+0.032 and [α/Fe] = 0.145 ± 0.053; these abundances are unusual, but not extraordinary, for a young star with thin-disk kinematics like KELT-21. High-resolution imaging observations revealed the presence of a pair of stellar companions to KELT-21, located at a separation of 1.âł2 and with a combined contrast of ÎKs = 6.39 ± 0.06 with respect to the primary. Although these companions are most likely physically associated with KELT-21, we cannot confirm this with our current data. If associated, the candidate companions KELT-21 B and C would each have masses of âŒ0.12 Mâ, a projected mutual separation of âŒ20 au, and a projected separation of âŒ500 au from KELT-21. KELT-21b may be one of only a handful of known transiting planets in hierarchical triple stellar systems
Orbit and Dynamical Mass of the Late-T Dwarf Gl 758 B
Gl 758 B is a late-T dwarf orbiting a metal-rich Sun-like star at a projected
separation of 1.6" (25 AU). We present four epochs of
astrometry of this system with NIRC2 at Keck Observatory spanning 2010 to 2017
together with 630 radial velocities (RVs) of the host star acquired over the
past two decades from McDonald Observatory, Keck Observatory, and the Automated
Planet Finder at Lick Observatory. The RVs reveal that Gl 758 is accelerating
with an evolving rate that varies between 2-5 m s yr, consistent
with the expected influence of the imaged companion Gl 758 B. A joint fit of
the RVs and astrometry yields a dynamical mass of 42
M for the companion with a robust lower limit of 30.5
M at the 4- level. Gl 758 B is on an eccentric orbit
( = 0.26-0.67 at 95% confidence) with a semimajor axis of =
AU and an orbital period of = yr,
which takes it within 9 AU from its host star at periastron passage.
Substellar evolutionary models generally underpredict the mass of Gl 758 B for
nominal ages of 1-6 Gyr that have previously been adopted for the host star.
This discrepancy can be reconciled if the system is older---which is consistent
with activity indicators and recent isochrone fitting of the host star---or
alternatively if the models are systematically overluminous by 0.1-0.2
dex. Gl 758 B is currently the lowest-mass directly imaged companion inducing a
measured acceleration on its host star. In the future, bridging RVs and
high-contrast imaging with the next generation of extremely large telescopes
and space-based facilities will open the door to the first dynamical mass
measurements of imaged exoplanets.Comment: AJ, accepte
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