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Kidney360 ◽  
2021 ◽  
pp. 10.34067/KID.0006132021
Author(s):  
Richard A. Hirth ◽  
Tammie Nahra ◽  
Jonathan H. Segal ◽  
Joseph Gunden ◽  
Grecia Marrufo ◽  
...  

Background: Poor adherence to scheduled dialysis treatments is common and can cause adverse clinical and economic outcomes. In 2015, the Center for Medicare and Medicaid Innovation launched the Comprehensive End-Stage Renal Disease Care (CEC) Model, a novel modification of the Accountable Care Organization framework. Many Model participants reported efforts to increase dialysis adherence and promptly reschedule missed treatments. Methods: With Medicare databases covering 2014-2019, we used difference-in-differences models to compare treatment adherence among patients aligned to 1,037 CEC facilities relative to those aligned to matched comparison facilities, while accounting for their differences at baseline. Using dates of service, we identified patients who typically received three weekly treatments and the days when treatments typically occurred. Skipped treatments were defined as days when the patient was not hospitalized but did not receive an expected treatment, and rescheduled treatments as days when a patient who had skipped their previous treatment received an additional treatment before their next expected treatment date. Results: Patients in the CEC Model had higher odds of attending as-scheduled sessions relative to the comparison group, though the effect was only marginally significant (OR=1.018, p=0.076). Effects were stronger among females (OR=1.028, p=0.062) than males (OR=1.010, p=0.485), and among those under 70 years (OR=1.024, p=0.040) than those 70+ (OR=0.999, p=0.963). The CEC was associated with higher odds of rescheduled sessions (OR=1.092, p<0.001). Effects were significant for both sexes, but were larger among males (OR=1.109, p<0.0001) than females (OR=1.070, p=0.012), and effects were significant among those under 70 years (OR=1.121, p<0.0001), but not those 70+ years (OR=0.990, p=0.796). Conclusions: The CEC Model is intended to incentivize strategies to prevent costly interventions. Because poor dialysis adherence may precipitate hospitalizations or other adverse events, many CEC Model participants encouraged adherence and promptly rescheduled missed treatments as strategic priorities. This study suggests the success of these efforts, though the absolute magnitudes of the effects were modest.


2021 ◽  
Vol 923 (2) ◽  
pp. 157
Author(s):  
Abigail J. Lee ◽  
Wendy L. Freedman ◽  
Barry F. Madore ◽  
Kayla A. Owens ◽  
In Sung Jang

Abstract The recently developed J-region asymptotic giant branch (JAGB) method has extraordinary potential as an extragalactic standard candle, capable of calibrating the absolute magnitudes of locally accessible Type Ia supernovae, thereby leading to an independent determination of the Hubble constant. Using Gaia Early Data Release 3 (EDR3) parallaxes, we calibrate the zero-point of the JAGB method, based on the mean luminosity of a color-selected subset of carbon-rich AGB stars. We identify Galactic carbon stars from the literature and use their near-infrared photometry and Gaia EDR3 parallaxes to measure their absolute J-band magnitudes. Based on these Milky Way parallaxes we determine the zero-point of the JAGB method to be M J = −6.14 ± 0.05 (stat) ± 0.11 (sys) mag. This Galactic calibration serves as a consistency check on the JAGB zero-point, agreeing well with previously published, independent JAGB calibrations based on geometric, detached eclipsing binary distances to the LMC and SMC. However, the JAGB stars used in this study suffer from the high parallax uncertainties that afflict the bright and red stars in EDR3, so we are not able to attain the higher precision of previous calibrations, and ultimately will rely on future improved DR4 and DR5 releases.


2021 ◽  
Vol 923 (2) ◽  
pp. 145
Author(s):  
Shu Wang ◽  
Xiaodian Chen

Abstract Red clump stars (RCs) are useful tracers of distances, extinction, chemical abundances, and Galactic structures and kinematics. Accurate estimation of RC parameters—absolute magnitude and intrinsic color—is the basis for obtaining high-precision RC distances. By combining astrometric data from Gaia; spectroscopic data from APOGEE and LAMOST; and multiband photometric data from Gaia, APASS, Pan-STARRS1, 2MASS, and WISE surveys, we use a Gaussian process regression to train machine learners to derive the multiband absolute magnitudes M λ and intrinsic colors ( λ 1 − λ 2 ) 0 for each spectral RC. The dependence of M λ on metallicity decreases from optical to infrared bands, while the dependence of M λ on age is relatively similar in each band. ( λ 1 − λ 2 ) 0 are more affected by metallicity than age. The RC parameters are not suitable to be represented by simple constants but are related to the Galactic stellar population structure. By analyzing the variation of M λ and ( λ 1 − λ 2 ) 0 in the spatial distribution, we construct (R, z) dependent maps of mean absolute magnitudes and mean intrinsic colors of the Galactic RCs. Through external and internal validation, we find that using three-dimensional (3D) parameter maps to determine RC parameters avoids systematic bias and reduces dispersion by about 20% compared to using constant parameters. Based on Gaia's EDR3 parallax, our 3D parameter maps, and extinction–distance profile selection, we obtain a photometric RC sample containing 11 million stars with distance and extinction measurements.


2021 ◽  
Vol 922 (1) ◽  
pp. L9
Author(s):  
Henry H. Hsieh ◽  
Colin O. Chandler ◽  
Larry Denneau ◽  
Alan Fitzsimmons ◽  
Nicolas Erasmus ◽  
...  

Abstract We report results from new and archival observations of the newly discovered active asteroid (248370) 2005 QN173 (also now designated Comet 433P), which has been determined to be a likely main-belt comet based on a subsequent discovery that it is recurrently active near perihelion. From archival data analysis, we estimate g ′ -, r ′ -, i ′ -, and z ′ -band absolute magnitudes for the nucleus of H g = 16.62 ± 0.13, H r = 16.12 ± 0.10, H i = 16.05 ± 0.11, and H z = 15.93 ± 0.08, corresponding to nucleus colors of g ′ − r ′ = 0.50 ± 0.16 , r ′ − i ′ = 0.07 ± 0.15 , and i ′ − z ′ = 0.12 ± 0.14 ; an equivalent V-band absolute magnitude of H V = 16.32 ± 0.08; and a nucleus radius of r n = 1.6 ± 0.2 km (using a V-band albedo of p V = 0.054 ± 0.012). Meanwhile, we find mean near-nucleus coma colors when 248370 is active of g ′ − r ′ = 0.47 ± 0.03 , r ′ − i ′ = 0.10 ± 0.04 , and i ′ − z ′ = 0.05 ± 0.05 and similar mean dust tail colors, suggesting that no significant gas coma is present. We find approximate ratios between the scattering cross sections of near-nucleus dust (within 5000 km of the nucleus) and the nucleus of A d /A n = 0.7 ± 0.3 on 2016 July 22 and 1.8 < A d /A n < 2.9 in 2021 July and August. During the 2021 observation period, the coma declined in intrinsic brightness by ∼0.35 mag (or ∼25%) in 37 days, while the surface brightness of the dust tail remained effectively constant over the same period. Constraints derived from the sunward extent of the coma and width of the tail as measured perpendicular to the orbit plane suggest that the terminal velocities of ejected dust grains are extremely slow (∼1 m s−1 for 1 μm particles), suggesting that the observed dust emission may be aided by rapid rotation of the nucleus lowering the effective escape velocity.


2021 ◽  
Vol 217 (6) ◽  
Author(s):  
Norbert Schörghofer ◽  
Mehdi Benna ◽  
Alexey A. Berezhnoy ◽  
Benjamin Greenhagen ◽  
Brant M. Jones ◽  
...  

AbstractWater ice, abundant in the outer solar system, is volatile in the inner solar system. On the largest airless bodies of the inner solar system (Mercury, the Moon, Ceres), water can be an exospheric species but also occurs in its condensed form. Mercury hosts water ice deposits in permanently shadowed regions near its poles that act as cold traps. Water ice is also present on the Moon, where these polar deposits are of great interest in the context of future lunar exploration. The lunar surface releases either OH or H2O during meteoroid showers, and both of these species are generated by reaction of implanted solar wind protons with metal oxides in the regolith. A consequence of the ongoing interaction between the solar wind and the surface is a surficial hydroxyl population that has been observed on the Moon. Dwarf planet Ceres has enough gravity to have a gravitationally-bound water exosphere, and also has permanently shadowed regions near its poles, with bright ice deposits found in the most long-lived of its cold traps. Tantalizing evidence for cold trapped water ice and exospheres of molecular water has emerged, but even basic questions remain open. The relative and absolute magnitudes of sources of water on Mercury and the Moon remain largely unknown. Exospheres can transport water to cold traps, but the efficiency of this process remains uncertain. Here, the status of observations, theory, and laboratory measurements is reviewed.


2021 ◽  
Author(s):  
Alvaro Alvarez-Candal ◽  
Paula Benavidez ◽  
Adriano Campo Bagatin ◽  
Toni Santana-Ros ◽  
Santiago Jimenez Corral

&lt;p class=&quot;p1&quot;&gt;&lt;span class=&quot;s1&quot;&gt;Phase curves of minor bodies describe their brightness change with phase angle, once distance effects have been removed. Using phase curves it is possible to obtain absolute magnitudes, useful parameters as they can be used as a proxy of sizes, with limitations due to albedo. In particular, in this work, we present phase curves of several thousands of minor objects in the filter system of the SLOAN Digital Sky Survey (SDSS).&lt;/span&gt;&lt;/p&gt; &lt;p class=&quot;p1&quot;&gt;&lt;span class=&quot;s1&quot;&gt;We obtained the phase curves using the Moving Object Catalog (MOC) of the SDSS including in the final uncertainties those of the input magnitudes and also the uncertainty due to the likely change in magnitude due to rotational variation of the objects. The final products are the absolute magnitudes H&lt;/span&gt;&lt;span class=&quot;s2&quot;&gt;&lt;sub&gt;&amp;#955;&lt;/sub&gt;&lt;/span&gt;&lt;span class=&quot;s1&quot;&gt; and G12&lt;/span&gt;&lt;span class=&quot;s2&quot;&gt;&lt;sub&gt;&amp;#955;&lt;/sub&gt;&lt;/span&gt;&lt;span class=&quot;s1&quot;&gt;, where &amp;#955; indicates any of the five central wavelengths of the SDSS filter system. We computed colors at zero phase angle, or absolute colors, that are not affected by phase effects and could be used as a benchmark for future studies. We also analyze the behavior at small phase angles (&lt;7.5 degrees) where the opposition effect dominates.&lt;/span&gt;&lt;/p&gt;


Author(s):  
Kazantsev Anatolii ◽  
Kazantseva Lilia

ABSTRACT The paper analyses possible transfers of bodies from the main asteroid belt (MBA) to the Centaur region. The orbits of asteroids in the 2:1 mean motion resonance (MMR) with Jupiter are analysed. We selected the asteroids that are in resonant orbits with e &gt; 0.3 whose absolute magnitudes H do not exceed 16 m. The total number of the orbits amounts to 152. Numerical calculations were performed to evaluate the evolution of the orbits over 100,000-year time interval with projects for the future. Six bodies are found to have moved from the 2:1 commensurability zone to the Centaur population. The transfer time of these bodies to the Centaur zone ranges from 4,600 to 70,000 yr. Such transfers occur after orbits leave the resonance and the bodies approach Jupiter Where after reaching sufficient orbital eccentricities bodies approach a terrestrial planet, their orbits go out of the MMR. Accuracy estimations are carried out to confirm the possible asteroid transfers to the Centaur region.


Author(s):  
J. Martikainen ◽  
K. Muinonen ◽  
A. Penttilä ◽  
A. Cellino ◽  
X.-B. Wang

2021 ◽  
Vol 502 (4) ◽  
pp. 6117-6139
Author(s):  
V Christiaens ◽  
M-G Ubeira-Gabellini ◽  
H Cánovas ◽  
P Delorme ◽  
B Pairet ◽  
...  

ABSTRACT Understanding how giant planets form requires observational input from directly imaged protoplanets. We used VLT/NACO and VLT/SPHERE to search for companions in the transition disc of 2MASS J19005804-3645048 (hereafter CrA-9), an accreting M0.75 dwarf with an estimated age of 1–2 Myr. We found a faint point source at ∼0.7-arcsec separation from CrA-9 (∼108 au projected separation). Our 3-epoch astrometry rejects a fixed background star with a 5σ significance. The near-IR absolute magnitudes of the object point towards a planetary-mass companion. However, our analysis of the 1.0–3.8$\,\mu$m spectrum extracted for the companion suggests it is a young M5.5 dwarf, based on both the 1.13-μm Na index and comparison with templates of the Montreal Spectral Library. The observed spectrum is best reproduced with high effective temperature ($3057^{+119}_{-36}$K) BT-DUSTY and BT-SETTL models, but the corresponding photometric radius required to match the measured flux is only $0.60^{+0.01}_{-0.04}$ Jovian radius. We discuss possible explanations to reconcile our measurements, including an M-dwarf companion obscured by an edge-on circum-secondary disc or the shock-heated part of the photosphere of an accreting protoplanet. Follow-up observations covering a larger wavelength range and/or at finer spectral resolution are required to discriminate these two scenarios.


2021 ◽  
Vol 14 ◽  
Author(s):  
Matthew Yedutenko ◽  
Marcus H. C. Howlett ◽  
Maarten Kamermans

The goal of sensory processing is to represent the environment of an animal. All sensory systems share a similar constraint: they need to encode a wide range of stimulus magnitudes within their narrow neuronal response range. The most efficient way, exploited by even the simplest nervous systems, is to encode relative changes in stimulus magnitude rather than the absolute magnitudes. For instance, the retina encodes contrast, which are the variations of light intensity occurring in time and in space. From this perspective, it is easy to understand why the bright plumage of a moving bird gains a lot of attention, while an octopus remains motionless and mimics its surroundings for concealment. Stronger contrasts simply cause stronger visual signals. However, the gains in retinal performance associated with higher contrast are far more than what can be attributed to just a trivial linear increase in signal strength. Here we discuss how this improvement in performance is reflected throughout different parts of the neural circuitry, within its neural code and how high contrast activates many non-linear mechanisms to unlock several sophisticated retinal computations that are virtually impossible in low contrast conditions.


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