109 research outputs found
Pediatric Feeding Disorder: Consensus Definition and Conceptual Framework
Pediatric feeding disorders (PFDs) lack a universally accepted definition. Feeding disorders require comprehensive assessment and treatment of 4 closely related, complementary domains (medical, psychosocial, and feeding skill-based systems and associated nutritional complications). Previous diagnostic paradigms have, however, typically defined feeding disorders using the lens of a single professional discipline and fail to characterize associated functional limitations that are critical to plan appropriate interventions and improve quality of life. Using the framework of the World Health Organization International Classification of Functioning, Disability, and Health, a unifying diagnostic term is proposed: “Pediatric Feeding Disorder” (PFD), defined as impaired oral intake that is not age-appropriate, and is associated with medical, nutritional, feeding skill, and/or psychosocial dysfunction. By incorporating associated functional limitations, the proposed diagnostic criteria for PFD should enable practitioners and researchers to better characterize the needs of heterogeneous patient populations, facilitate inclusion of all relevant disciplines in treatment planning, and promote the use of common, precise, terminology necessary to advance clinical practice, research, and health-care policy
The IGRINS YSO Survey III: Stellar parameters of pre-main sequence stars in Ophiuchus and Upper Scorpius
We used the Immersion GRating Infrared Spectrometer (IGRINS) to determine
fundamental parameters for 61 K- and M-type young stellar objects (YSOs)
located in the Ophiuchus and Upper Scorpius star-forming regions. We employed
synthetic spectra and a Markov chain Monte Carlo approach to fit specific
K-band spectral regions and determine the photospheric temperature (), surface gravity ( g), magnetic field strength (B), projected
rotational velocity (), and K-band veiling (). We
determined B for 46% of our sample. Stellar parameters were compared to
the results from Taurus-Auriga and the TW Hydrae Association (TWA) presented in
Paper I of this series. We classified all the YSOs in the IGRINS survey with
infrared spectral indices from 2MASS and WISE photometry between 2 and
24~m. We found that Class II YSOs typically have lower g and , similar B, and higher K-band veiling than their Class III counterparts.
Additionally, we determined the stellar parameters for a sample of K and M
field stars also observed with IGRINS. We have identified intrinsic
similarities and differences at different evolutionary stages with our
homogeneous determination of stellar parameters in the IGRINS YSO Survey.
Considering g as a proxy for age, we found that the Ophiuchus and Taurus
samples have a similar age. We also find that Upper Scorpius and TWA YSOs have
similar ages, and are more evolved than Ophiuchus/Taurus YSOs.Comment: 21 pages, 8 figures, 4 tables. Accepted for publication in Ap
A highly efficient measure of mass segregation in star clusters
Investigations of mass segregation are of vital interest for the
understanding of the formation and dynamical evolution of stellar systems on a
wide range of spatial scales. Our method is based on the minimum spanning tree
(MST) that serves as a geometry-independent measure of concentration. Compared
to previous such approaches we obtain a significant refinement by using the
geometrical mean as an intermediate-pass. It allows the detection of mass
segregation with much higher confidence and for much lower degrees of mass
segregation than other approaches. The method shows in particular very clear
signatures even when applied to small subsets of the entire population. We
confirm with high significance strong mass segregation of the five most massive
stars in the Orion Nebula Cluster (ONC). Our method is the most sensitive
general measure of mass segregation so far and provides robust results for both
data from simulations and observations. As such it is ideally suited for
tracking mass segregation in young star clusters and to investigate the long
standing paradigm of primordial mass segregation by comparison of simulations
and observations.Comment: 11 pages, 9 figures, accepted by A&
Refining the Stellar Parameters of Ceti: a Pole-on Solar Analog
To accurately characterize the planets a star may be hosting, stellar
parameters must first be well-determined. Ceti is a nearby solar analog
and often a target for exoplanet searches. Uncertainties in the observed
rotational velocities have made constraining Ceti's inclination
difficult. For planet candidates from radial velocity (RV) observations, this
leads to substantial uncertainties in the planetary masses, as only the minimum
mass () can be constrained with RV. In this paper, we used new
long-baseline optical interferometric data from the CHARA Array with the MIRC-X
beam combiner and extreme precision spectroscopic data from the Lowell
Discovery Telescope with EXPRES to improve constraints on the stellar
parameters of Ceti. Additional archival data were obtained from a
Tennessee State University Automatic Photometric Telescope and the Mount Wilson
Observatory HK project. These new and archival data sets led to improved
stellar parameter determinations, including a limb-darkened angular diameter of
mas and rotation period of days. By combining
parameters from our data sets, we obtained an estimate for the stellar
inclination of . This nearly-pole-on orientation has implications
for the previously-reported exoplanets. An analysis of the system dynamics
suggests that the planetary architecture described by Feng et al. (2017) may
not retain long-term stability for low orbital inclinations. Additionally, the
inclination of Ceti reveals a misalignment between the inclinations of
the stellar rotation axis and the previously-measured debris disk rotation axis
().Comment: 14 pages, 3 figures, 4 tables, 1 appendix, accepted for publication
to A
Endangered right whales enhance primary productivity in the bay of fundy
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Marine mammals have recently been documented as important facilitators of rapid and efficient nutrient recycling in coastal and offshore waters. Whales enhance phytoplankton nutrition by releasing fecal plumes near the surface after feeding and by migrating from highly productive, high-latitude feeding areas to low-latitude nutrient-poor calving areas. In this study, we measured NH4 + and PO4 3- release rates from the feces of North Atlantic right whales (Eubalaena glacialis), a highly endangered baleen whale. Samples for this species were primarily collected by locating aggregations of whales in surface- Active groups (SAGs), which typically consist of a central female surrounded by males competing for sexual activity. When freshly collected feces were incubated in seawater, high initial rates of N release were generally observed, which decreased to near zero within 24 hours of sampling, a pattern that is consistent with the active role of gut microflora on fecal particles. We estimate that at least 10% of particulate N in whale feces becomes available as NH4 + within 24 hours of defecation. Phosphorous was also abundant in fecal samples: Initial release rates of PO4 3- were higher than for NH4 +, yielding low N/P nutrient ratios over the course of our experiments. The rate of PO4 3- release was thus more than sufficient to preclude the possibility that nitrogenous nutrients supplied by whales would lead to phytoplankton production limited by P availability. Phytoplankton growth experiments indicated that NH4 + released from whale feces enhance productivity, as would be expected, with no evidence that fecal metabolites suppress growth. Although North Atlantic right whales are currently rare (approximately 450 individuals), they once numbered about 14,000 and likely played a substantial role in recycling nutrients in areas where they gathered to feed and mate. Even though the NH4 + released from fresh whale fecal material is a small fraction of total whale fecal nitrogen, and recognizing the fact that the additional nitrogen released in whale urine would be difficult to measure in a field study, the results of this study support the idea that the distinctive isotopic signature of the released NH4 + could be used to provide a conservative estimate of the contribution of the whale pump to primary productivity in coastal regions where whales congregate
Efficacious Intermittent Dosing of a Novel JAK2 Inhibitor in Mouse Models of Polycythemia Vera
A high percentage of patients with the myeloproliferative disorder polycythemia vera (PV) harbor a Val617→Phe activating mutation in the Janus kinase 2 (JAK2) gene, and both cell culture and mouse models have established a functional role for this mutation in the development of this disease. We describe the properties of MRLB-11055, a highly potent inhibitor of both the WT and V617F forms of JAK2, that has therapeutic efficacy in erythropoietin (EPO)-driven and JAK2V617F-driven mouse models of PV. In cultured cells, MRLB-11055 blocked proliferation and induced apoptosis in a manner consistent with JAK2 pathway inhibition. MRLB-11055 effectively prevented EPO-induced STAT5 activation in the peripheral blood of acutely dosed mice, and could prevent EPO-induced splenomegaly and erythrocytosis in chronically dosed mice. In a bone marrow reconstituted JAK2V617F-luciferase murine PV model, MRLB-11055 rapidly reduced the burden of JAK2V617F-expressing cells from both the spleen and the bone marrow. Using real-time in vivo imaging, we examined the kinetics of disease regression and resurgence, enabling the development of an intermittent dosing schedule that achieved significant reductions in both erythroid and myeloid populations with minimal impact on lymphoid cells. Our studies provide a rationale for the use of non-continuous treatment to provide optimal therapy for PV patients
Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans
Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have
fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in
25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16
regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of
correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP,
while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in
Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium
(LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region.
Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant
enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the
refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa,
an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of
PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent
signals within the same regio
Multi-messenger observations of a binary neutron star merger
On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta
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