96 research outputs found
The SOUL view of IRAS20126+4104. Kinematics and variability of the H jet from a massive protostar
We exploit the increased sensitivity of the recently installed AO SOUL at the
LBT to obtain new high-spatial-resolution NIR images of the massive young
stellar object IRAS20126+4104 and its outflow. We aim to derive the jet proper
motions and kinematics, as well as to study its photometric variability by
combining the novel performances of SOUL together with previous NIR images. We
used both broad-band (, ) and narrow-band (Br, H2)
observations from a number of NIR cameras
(UKIRT/UFTI,SUBARU/CIAO,TNG/NICS,LBT/PISCES,and LBT/LUCI1) to derive maps of
the continuum and the H emission in the 2.12 m line. Three sets of
images, obtained with AO systems (CIAO,2003; FLAO,2012; SOUL,2020), allowed us
to derive the proper motions of a large number of H knots along the jet.
Photometry from all images was used to study the jet variability. We derived
knot proper motions in the range of 1.7-20.3 mas yr (i.e. 13-158 km
s at 1.64 kpc, avg. outflow tangential velocity 80 km s).
The derived knot dynamical age spans a 200-4000 yr interval. A ring-like
H feature near the protostar location exhibits peculiar kinematics and may
represent the outcome of a wide-angle wind impinging on the outflow cavity.
Both H geometry and velocities agree with those inferred from proper
motions of the HO masers, located at a smaller distance from the protostar.
Although the total H line emission from the knots does not exhibit time
variations at a 0.3 mag level, we have found a clear continuum
flux variation (radiation scattered by the dust in the cavity opened by the
jet) which is anti-correlated between the blue-shifted and red-shifted lobes
and may be periodic (with a period of 12-18 yr). We suggest that the
continuum variability might be related to inner-disc oscillations which have
also caused the jet precession.Comment: 26 pages, 22 figures, 2 mpeg files, accepted by Astronomy &
Astrophysic
Near-Infrared Observations of Outflows and YSOs in the Massive Star-Forming Region AFGL 5180
Methods: Broad- and narrow-band imaging of AFGL 5180 was made in the NIR with
the LBT, in both seeing-limited (\sim0.5\arcsec) and high angular resolution
(\sim0.09\arcsec) Adaptive Optics (AO) modes, as well as with HST. Archival
ALMA continuum data was also utilized.
Results: At least 40 jet knots were identified via NIR emission from H
and [FeII] tracing shocked gas. Bright jet knots outflowing from the central
most massive protostar, S4, are detected towards the east of the source and are
resolved in fine detail with the AO imaging. Additional knots are distributed
throughout the field, likely indicating the presence of multiple driving
sources. Sub-millimeter sources detected by ALMA are shown to be grouped in two
main complexes, AFGL 5180 M and a small cluster \sim15\arcsec to the south,
AFGL 5180 S. From our NIR continuum images we identify YSO candidates down to
masses of . Combined with the sub-mm sources, this yields a
surface number density of such YSOs of within a
projected radius of about 0.1 pc. Such a value is similar to those predicted by
models of both Core Accretion from a turbulent clump environment and
Competitive Accretion. The radial profile of is relatively flat on scales
out to 0.2~pc, with only modest enhancement around the massive protostar inside
0.05~pc.
Conclusions: This study demonstrates the utility of high-resolution NIR
imaging, in particular with AO, for detecting outflow activity and YSOs in
distant regions. The presented images reveal the complex morphology of
outflow-shocked gas within the large-scale bipolar flow of a massive protostar,
as well as clear evidence for several other outflow driving sources in the
region. Finally, this work presents a novel approach to compare the observed
YSO surface number density from our study against different models of massive
star formation.Comment: Accepted to Astronomy & Astrophysics (A&A
GMP-selected dual and lensed AGNs: selection function and classification based on near-IR colors and resolved spectra from VLT/ERIS, KECK/OSIRIS, and LBT/LUCI
The Gaia-Multi-Peak (GMP) technique can be used to identify large numbers of
dual or lensed AGN candidates at sub-arcsec separation, allowing us to study
both multiple SMBHs in the same galaxy and rare, compact lensed systems. The
observed samples can be used to test the predictions of the models of SMBH
merging once 1) the selection function of the GMP technique is known, and 2)
each system has been classified as dual AGN, lensed AGN, or AGN/star alignment.
Here we show that the GMP selection is very efficient for separations above
0.15'' when the secondary (fainter) object has magnitude G<20.5. We present the
spectroscopic classification of five GMP candidates using VLT/ERIS and
Keck/OSIRIS, and compare them with the classifications obtained from: a) the
near-IR colors of 7 systems obtained with LBT/LUCI, and b) the analysis of the
total, spatially-unresolved spectra. We conclude that colors and integrated
spectra can already provide reliable classifications of many systems. Finally,
we summarize the confirmed dual AGNs at z>0.5 selected by the GMP technique,
and compare this sample with other such systems from the literature, concluding
that GMP can provide a large number of confirmed dual AGNs at separations below
7 kpc.Comment: 14 pages,A&A, in pres
GMP-selected dual and lensed AGNs: Selection function and classification based on near-IR colors and resolved spectra from VLT/ERIS, Keck/OSIRIS, and LBT/LUCI
The Gaia Multipeak (GMP) technique can be used to identify large numbers of dual or lensed active galactic nucleus (AGN) candidates at subarcsec separation, allowing us to study both multiple supermassive black holes (SMBHs) in the same galaxy and rare, compact lensed systems. The observed samples can be used to test the predictions of the models of SMBH merging when (1) the selection function of the GMP technique is known, and (2) each system has been classified as a dual AGN, a lensed AGN, or an AGN/star alignment. Here we show that the GMP selection is very efficient for separations above 0:15′′ when the secondary (fainter) object has a magnitude G ≤ 20:5. We present the spectroscopic classification of five GMP candidates using VLT/ERIS and Keck/OSIRIS and compare them with the classifications obtained from (a) the near-IR colors of seven systems obtained with LBT/LUCI, and (b) the analysis of the total spatially unresolved spectra. We conclude that colors and integrated spectra can already provide reliable classifications of many systems. Finally, we summarize the confirmed dual AGNs at z > 0:5 selected by the GMP technique, and compare this sample with other such systems from the literature, concluding that GMP can provide a large number of confirmed dual AGNs at separations below 7 kpc
Paradoxical Evidence Integration in Rapid Decision Processes
Decisions about noisy stimuli require evidence integration over time. Traditionally, evidence integration and decision making are described as a one-stage process: a decision is made when evidence for the presence of a stimulus crosses a threshold. Here, we show that one-stage models cannot explain psychophysical experiments on feature fusion, where two visual stimuli are presented in rapid succession. Paradoxically, the second stimulus biases decisions more strongly than the first one, contrary to predictions of one-stage models and intuition. We present a two-stage model where sensory information is integrated and buffered before it is fed into a drift diffusion process. The model is tested in a series of psychophysical experiments and explains both accuracy and reaction time distributions
Structure-Guided Evolution of Potent and Selective CHK1 Inhibitors through Scaffold Morphing
Pyrazolopyridine inhibitors with low micromolar potency for CHK1 and good selectivity against CHK2 were previously identified by fragment-based screening. The optimization of the pyrazolopyridines to a series of potent and CHK1-selective isoquinolines demonstrates how fragment-growing and scaffold morphing strategies arising from a structure-based understanding of CHK1 inhibitor binding can be combined to successfully progress fragment-derived hit matter to compounds with activity in vivo. The challenges of improving CHK1 potency and selectivity, addressing synthetic tractability, and achieving novelty in the crowded kinase inhibitor chemical space were tackled by multiple scaffold morphing steps, which progressed through tricyclic pyrimido[2,3-b]azaindoles to N-(pyrazin-2-yl)pyrimidin-4-amines and ultimately to imidazo[4,5-c]pyridines and isoquinolines. A potent and highly selective isoquinoline CHK1 inhibitor (SAR-020106) was identified, which potentiated the efficacies of irinotecan and gemcitabine in SW620 human colon carcinoma xenografts in nude mice
Serotonergic Contribution to Boys' Behavioral Regulation
Animal and human adult studies reveal a contribution of serotonin to behavior regulation. Whether these findings apply to children is unclear. The present study investigated serotonergic functioning in boys with a history of behavior regulation difficulties through a double-blind, acute tryptophan supplementation procedure.Participants were 23 boys (age 10 years) with a history of elevated physical aggression, recruited from a community sample. Eleven were given a chocolate milkshake supplemented with 500 mg tryptophan, and 12 received a chocolate milkshake without tryptophan. Boys engaged in a competitive reaction time game against a fictitious opponent, which assessed response to provocation, impulsivity, perspective taking, and sharing. Impulsivity was further assessed through a Go/No-Go paradigm. A computerized emotion recognition task and a staged instrumental help incident were also administered.Boys, regardless of group, responded similarly to high provocation by the fictitious opponent. However, boys in the tryptophan group adjusted their level of responding optimally as a function of the level of provocation, whereas boys in the control group significantly decreased their level of responding towards the end of the competition. Boys in the tryptophan group tended to show greater perspective taking, tended to better distinguish facial expressions of fear and happiness, and tended to provide greater instrumental help to the experimenter.The present study provides initial evidence for the feasibility of acute tryptophan supplementation in children and some effect of tryptophan supplementation on children's behaviors. Further studies are warranted to explore the potential impact of increased serotonergic functioning on boys' dominant and affiliative behaviors
Spread of artemisinin resistance in Plasmodium falciparum malaria.
BACKGROUND: Artemisinin resistance in Plasmodium falciparum has emerged in Southeast Asia and now poses a threat to the control and elimination of malaria. Mapping the geographic extent of resistance is essential for planning containment and elimination strategies. METHODS: Between May 2011 and April 2013, we enrolled 1241 adults and children with acute, uncomplicated falciparum malaria in an open-label trial at 15 sites in 10 countries (7 in Asia and 3 in Africa). Patients received artesunate, administered orally at a daily dose of either 2 mg per kilogram of body weight per day or 4 mg per kilogram, for 3 days, followed by a standard 3-day course of artemisinin-based combination therapy. Parasite counts in peripheral-blood samples were measured every 6 hours, and the parasite clearance half-lives were determined. RESULTS: The median parasite clearance half-lives ranged from 1.9 hours in the Democratic Republic of Congo to 7.0 hours at the Thailand-Cambodia border. Slowly clearing infections (parasite clearance half-life >5 hours), strongly associated with single point mutations in the "propeller" region of the P. falciparum kelch protein gene on chromosome 13 (kelch13), were detected throughout mainland Southeast Asia from southern Vietnam to central Myanmar. The incidence of pretreatment and post-treatment gametocytemia was higher among patients with slow parasite clearance, suggesting greater potential for transmission. In western Cambodia, where artemisinin-based combination therapies are failing, the 6-day course of antimalarial therapy was associated with a cure rate of 97.7% (95% confidence interval, 90.9 to 99.4) at 42 days. CONCLUSIONS: Artemisinin resistance to P. falciparum, which is now prevalent across mainland Southeast Asia, is associated with mutations in kelch13. Prolonged courses of artemisinin-based combination therapies are currently efficacious in areas where standard 3-day treatments are failing. (Funded by the U.K. Department of International Development and others; ClinicalTrials.gov number, NCT01350856.)
Use of anticoagulants and antiplatelet agents in stable outpatients with coronary artery disease and atrial fibrillation. International CLARIFY registry
Finishing the euchromatic sequence of the human genome
The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead
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