We provide a calculation of Pan-STARRS' ability to detect objects similar to the interstellar object 1I/2017 U1 (hereafter 'Oumuamua), including the most detectable approach vectors and the effect of ...object size on detection efficiency. Using our updated detection cross section, we infer an interstellar number density of such objects ( ). This translates to a mass density of that cannot be populated unless every star is contributing. We find that, given current models, such a number density cannot arise from the ejection of inner solar system material during planet formation. We note that a stellar system's Oort cloud will be released after a star's main-sequence life time and may provide enough material to obtain the observed density. The challenge is that Oort cloud bodies are icy and 'Oumuamua was observed to be dry, which necessitates a crust-generation mechanism.
Efficient therapeutic options are needed to control the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that has caused more than 922,000 fatalities as of 13 September 2020. We ...report the isolation and characterization of two ultrapotent SARS-CoV-2 human neutralizing antibodies (S2E12 and S2M11) that protect hamsters against SARS-CoV-2 challenge. Cryo-electron microscopy structures show that S2E12 and S2M11 competitively block angiotensin-converting enzyme 2 (ACE2) attachment and that S2M11 also locks the spike in a closed conformation by recognition of a quaternary epitope spanning two adjacent receptor-binding domains. Antibody cocktails that include S2M11, S2E12, or the previously identified S309 antibody broadly neutralize a panel of circulating SARS-CoV-2 isolates and activate effector functions. Our results pave the way to implement antibody cocktails for prophylaxis or therapy, circumventing or limiting the emergence of viral escape mutants.
We examine the early phase intrinsic (B − V)0 color evolution of a dozen SNe Ia discovered within three days of the inferred time of first light (tfirst) and have (B − V)0 color information beginning ...within five days of tfirst. The sample indicates there are two distinct early populations. The first is a population exhibiting blue colors that slowly evolve, and the second population exhibits red colors and evolves more rapidly. We find that the early blue events are all 1991T/1999aa-like with more luminous, slower declining light curves than those exhibiting early red colors. Placing the first sample on the Branch diagram (i.e., ratio of Si ii λλ5972, 6355 pseudo-Equivalent widths) indicates that all blue objects are of the Branch shallow silicon (SS) spectral type, while all early red events except for the 2000cx-like SN 2012fr are of the Branch Core Normal (CN) or CooL (CL) type. A number of potential processes contributing to the early emission are explored, and we find that, in general, the viewing-angle dependance inherent in the companion collision model is inconsistent with all of the SS objects with early-time observations being blue and exhibiting an excess. We caution that great care must be taken when interpreting early phase light curves as there may be a variety of physical processes that are possibly at play and significant theoretical work remains to be done.
Nociceptin/Orphanin FQ (N/OFQ) is a 17 amino acid peptide that was deorphanized in 1995. The generation of specific agonists, antagonists and receptor deficient mice and rats has enabled progress in ...elucidating the biological functions of N/OFQ. Additionally, radio-imaging technologies have been advanced for investigation of this system in animals and humans. Together with traditional neurobehavioral techniques, these tools have been utilized to identify the biological significance of the N/OFQ system and its interacting partners. The present review focuses on the role of N/OFQ in the regulation of feeding, body weight homeostasis, stress, the stress-related psychiatric disorders of depression and anxiety, and in drug and alcohol dependence. Critical evaluation of the current scientific preclinical literature suggests that small molecule modulators of nociceptin opioid peptide receptors (NOP) might be useful in the treatment of diseases related to these biological functions. In particular, the literature data suggest that antagonism of NOP receptors will produce anti-obesity and antidepressant activities in humans. However, there are also contradictory data discussed. The current literature on the role of N/OFQ in anxiety and addiction, on the other hand points primarily to a role of agonist modulation being potentially therapeutic. Some drug-like molecules that function either as agonists or antagonists of NOP receptors have been optimized for human clinical study to test some of these hypotheses. The discovery of PET ligands for NOP receptors, combined with the pharmacological tools and burgeoning preclinical data set discussed here bodes well for a rapid advancement of clinical understanding and potential therapeutic benefit.
Abstract
We present the discovery that ASASSN-14ko is a periodically flaring active galactic nucleus at the center of the galaxy ESO 253-G003. At the time of its discovery by the All-Sky Automated ...Survey for Supernovae (ASAS-SN), it was classified as a supernova close to the nucleus. The subsequent 6 yr of
V
- and
g
-band ASAS-SN observations revealed that ASASSN-14ko has nuclear flares occurring at regular intervals. The 17 observed outbursts show evidence of a decreasing period over time, with a mean period of
P
0
= 114.2 ± 0.4 days and a period derivative of
. The most recent outburst in 2020 May, which took place as predicted, exhibited spectroscopic changes during the rise and had a UV bright, blackbody spectral energy distribution similar to tidal disruption events (TDEs). The X-ray flux decreased by a factor of 4 at the beginning of the outburst and then returned to its quiescent flux after ∼8 days. The Transiting Exoplanet Survey Satellite observed an outburst during Sectors 4–6, revealing a rise time of 5.60 ± 0.05 days in the optical and a decline that is best fit with an exponential model. We discuss several possible scenarios to explain ASASSN-14ko’s periodic outbursts, but currently favor a repeated partial TDE. The next outbursts should peak in the optical on UT 2020 September 7.4±1.1 and UT 2020 December 26.5±1.4.
We present the first results of our ongoing project conducting simultaneous multiwavelength observations of flares on nearby active M dwarfs. We acquired data of the nearby dM3.5e star EV Lac using ...five different observatories: NASA's Transiting Exoplanet Survey Satellite (TESS), NASA's Neil Gehrels Swift Observatory (Swift), NASA's Neutron Interior Composition Explorer (NICER), the University of Hawaii 2.2-meter telescope (UH88), and the Las Cumbres Observatory Global Telescope (LCOGT) Network. During the ∼25 days of TESS observations, we acquired three simultaneous UV/X-ray observations using Swift that total ∼18 ks, 21 simultaneous epochs totaling ∼98 ks of X-ray data using NICER, one observation (∼3 hr) with UH88, and one observation (∼3 hr) with LCOGT. We identified 56 flares in the TESS light curve with estimated energies in the range log E(T) (erg) = (30.5–33.2), nine flares in the Swift UVM2 light curve with estimated energies in the range log E(UV) (erg) = (29.3–31.1), 14 flares in the NICER light curve with estimated minimum energies in the range log E(N) (erg) = (30.5–32.3), and 1 flare in the LCOGT light curve with log E(L) (erg) = 31.6. We find that the flare frequency distributions (FFDs) of TESS and NICER flares have comparable slopes, β(T) = −0.67 ± 0.09 and β(N) = − 0.65 ± 0.19, and the FFD of UVOT flares has a shallower slope (β(U) = −0.38 ± 0.13). Furthermore, we do not find conclusive evidence for either the first ionization potential (FIP) or the inverse FIP effect during coronal flares on EV Lac.
We present the first discovery from the COol Companions ON Ultrawide orbiTS (COCONUTS) program, a large-scale survey for wide-orbit planetary and substellar companions. We have discovered a comoving ...system COCONUTS-1, composed of a hydrogen-dominated white dwarf (PSO J058.9855+45.4184; d = 31.5 pc) and a T4 companion (PSO J058.9869+45.4296) at a 40 6 (1280 au) projected separation. We derive physical properties for COCONUTS-1B from (1) its near-infrared spectrum using cloudless Sonora atmospheric models, and (2) its luminosity and the white dwarf's age ( Gyr) using Sonora evolutionary models. The two methods give consistent temperatures and radii, but atmospheric models infer a lower surface gravity and therefore an unphysically young age. Assuming evolutionary model parameters ( K, dex, ), we find that cloudless model atmospheres have brighter Y- and J-band fluxes than the data, suggesting that condensate clouds have not fully dispersed around 1300 K. The W2 flux (4.6 m) of COCONUTS-1B is fainter than models, suggesting non-equilibrium mixing of CO. To investigate the gravity dependence of the L/T transition, we compile all 60 known L6−T6 benchmarks and derive a homogeneous set of temperatures, surface gravities, and masses. As is well known, young, low-gravity late-L dwarfs have significantly fainter, redder near-infrared photometry and 200-300 K cooler temperatures than old, high-gravity objects. Our sample now reveals such gravity dependence becomes weaker for T dwarfs, with young objects having comparable near-infrared photometry and 100 K cooler temperatures compared to old objects. Finally, we find that young objects have a larger amplitude J-band brightening than old objects, and also brighten at H band as they cross the L/T transition.
Mutations in the transcription factor Forkhead box p1 (FOXP1) are causative for neurodevelopmental disorders such as autism. However, the function of FOXP1 within the brain remains largely ...uncharacterized. Here, we identify the gene expression program regulated by FoxP1 in both human neural cells and patient-relevant heterozygous Foxp1 mouse brains. We demonstrate a role for FoxP1 in the transcriptional regulation of autism-related pathways as well as genes involved in neuronal activity. We show that Foxp1 regulates the excitability of striatal medium spiny neurons and that reduction of Foxp1 correlates with defects in ultrasonic vocalizations. Finally, we demonstrate that FoxP1 has an evolutionarily conserved role in regulating pathways involved in striatal neuron identity through gene expression studies in human neural progenitors with altered FOXP1 levels. These data support an integral role for FoxP1 in regulating signaling pathways vulnerable in autism and the specific regulation of striatal pathways important for vocal communication.
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