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In a trial involving patients with relapsed or refractory chronic lymphocytic leukemia, the BCL2 inhibitor venetoclax in combination with rituximab resulted in a higher 2-year rate of progression-free survival than bendamustine in combination with rituximab (85% vs. 36%).

Obinutuzumab, a glycoengineered anti-CD20 antibody with increased killing capacity, outperformed rituximab when used in combination with chlorambucil in patients with chronic lymphocytic leukemia who had coexisting illnesses. Chronic lymphocytic leukemia (CLL), which is characterized by a neoplastic accumulation of B lymphocytes, 1 is the most common leukemia in Western countries. The majority of patients with CLL are older than 70 years of age, and many present with coexisting conditions. 2 , 3 In the past, CLL was treated with chemotherapy without improving survival. 4 – 8 The addition of the monoclonal anti-CD20 antibody rituximab to fludarabine and cyclophosphamide has been shown to prolong overall survival in physically fit patients with previously untreated CLL. 9 – 11 However, randomized trials have not shown that targeting the CD20 antigen in patients with CLL and coexisting conditions . . .

Much is known about the processes driving accretion from protoplanetary disks onto low-mass pre-main-sequence stars (T Tauri stars). Nevertheless, it is unclear how accretion stops. To determine the accretion properties and their relation to stellar properties and gain insight into the last stages of accretion, we present a detailed analysis of 24 low and possible accretors, previously identified using the He i λ10830 line. We model moderate-resolution Hα profiles of these stars using magnetospheric accretion flow models that account for the chromospheric contribution at the line center. Based on parameters derived from the fits of 20 stars that can be reproduced with the models, we find a power-law relation between the disk truncation radius and the mass accretion rate consistent with predictions from theory and simulations. Comparing the corotation and truncation radii, we find that most of our targets are accreting in the unstable regime and rule out the propeller as the main process stopping accretion. For the truncation radius to be the same as the magnetic radius, the dipole magnetic field and/or the efficiency parameter ξ need to be smaller than previously determined, suggesting that higher-order fields dominate in low accretion rates. Lastly, we determine that the lowest accretion rates that can be detected by Hα line modeling are (1–3) × 10−11 M ☉ yr−1 for M3 stars and (3–5) × 10−11 M ☉ yr−1 for K5 stars. These limits are lower than the observed accretion rates in our sample, suggesting that we have reached a physical lower limit. This limit, Ṁ∼10−10M☉yr−1 , is consistent with EUV-dominated photoevaporation.

We use TESS full-frame imaging data to investigate the angular momentum evolution of young stars in the Orion Complex. We confirm recent findings that stars with rotation periods faster than 2 days are overwhelmingly binaries, with typical separations of tens of au; such binaries quickly clear their disks, leading to a tendency for rapid rotators to be diskless. Among (nominally single) stars with rotation periods slower than 2 days, we observe the familiar gyrochronological horseshoe-shaped relationship of rotation period versus T eff, indicating that the processes that govern the universal evolution of stellar rotation on gigayear timescales are already in place within the first few megayears. Using spectroscopic vsini , we determine the distribution of sini , revealing that the youngest stars are biased toward more pole-on orientations, which may be responsible for the systematics between stellar mass and age observed in star-forming regions. We are also able for the first time to make empirical, quantitative measurements of angular momenta and their time derivatives as functions of stellar mass and age, finding these relationships to be much simpler and monotonic as compared to the complex relationships involving rotation period alone; evidently, the relationship between rotation period and T eff is largely a reflection of mass-dependent stellar structure and not of angular momentum per se. Our measurements show that the stars experience spin-down torques in the range of ∼1037 erg at ∼1 Myr to ∼1035 erg at ∼10 Myr, which provide a crucial empirical touchstone for theoretical mechanisms of angular momentum loss in young stars.

We present precise measurements of radial (RV) and projected rotational ( vsini ) velocities of a sample of 258 M6 to L2 dwarfs with multiepoch, high-resolution (λ/Δλ = 22,500), near-infrared (1.514–1.696 μm) spectroscopic observations reported in the Apache Point Observatory Galactic Evolution Experiment Data Release 17. The spectra were modeled using a Markov Chain Monte Carlo forward-modeling method, which achieved median precisions of σ RV = 0.4 km s−1 and σvsini = 1.1 km s−1. One-half of our sample (138 sources) are previously known members of nearby young clusters and moving groups, and we identified three new kinematic members of the Argus or Carina Near moving groups, 2MASS J05402570+2448090, 2MASS J14093200+4138080, and 2MASS J21272531+5553150. Excluding these sources, we find that the majority of our sample have kinematics consistent with the Galactic thin disk, and 11 sources are associated with the intermediate thin/thick disk. The field sample has a velocity dispersion of 38.2 ± 0.3 km s−1, equivalent to an age of 3.30 ± 0.19 Gyr based on empirical age–velocity dispersion relations, and a median vsini of 17 km s−1. For 172 sources with multiepoch observations, we identified 37 as having significant RV variations, and determined preliminary orbit parameters for 26 sources with four or more epochs, nine of which are short-period binary candidates. For 40 sources with photometric variability periods from the literature less than 5 days and vsini > 20 km s−1, we find a decline in projected radii ( Rsini ) with age congruent with evolutionary models. Finally, we also present multiepoch RV and vsini measurements for additional 444 candidate ultracool dwarfs.

We present a spectroscopic analysis of a sample of 48 M-dwarf stars (0.2 M ⊙ < M < 0.6 M ⊙) from the Hyades open cluster using high-resolution H-band spectra from the Sloan Digital Sky Survey/Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey. Our methodology adopts spectrum synthesis with LTE MARCS model atmospheres, along with the APOGEE Data Release 17 line list, to determine effective temperatures, surface gravities, metallicities, and projected rotational velocities. The median metallicity obtained for the Hyades M dwarfs is [M/H] = 0.09 ± 0.03 dex, indicating a small internal uncertainty and good agreement with optical results for Hyades red giants. Overall, the median radii are larger than predicted by stellar models by 1.6% ± 2.3% and 2.4% ± 2.3%, relative to a MIST and DARTMOUTH isochrone, respectively. We emphasize, however, that these isochrones are different, and the fractional radius inflation for the fully and partially convective regimes have distinct behaviors depending on the isochrone. Using a MIST isochrone there is no evidence of radius inflation for the fully convective stars, while for the partially convective M dwarfs the radii are inflated by 2.7% ± 2.1%, which is in agreement with predictions from models that include magnetic fields. For the partially convective stars, rapid rotators present on average higher inflation levels than slow rotators. The comparison with SPOTS isochrone models indicates that the derived M-dwarf radii can be explained by accounting for stellar spots in the photosphere of the stars, with 76% of the studied M dwarfs having up to 20% spot coverage, and the most inflated stars with ∼20%–40% spot coverage.

We present a spectroscopic analysis of T Tauri stars (TTSs) observed with the wide-field multifiber spectrograph LAMOST in the substellar associations Ori OB1a located in the Orion Star-forming Complex. Based on GAIA-DR3 data, we selected stars with proper motions and parallaxes expected for TTSs belonging to the young association. We perform a spectroscopic analysis to obtain the spectral types and measure the equivalent widths of Li i and Hα to confirm the youth of the stars and estimate the accretion status. We also estimate extinctions, masses, and ages for the studied sample. Out of 342 TTSs with spectroscopic and kinematic properties indicating their membership of the subassociation, 2 are reported here for the first time. Finally, we detect four stellar kinematic groups located at different distances, two in the north fields and two in the south field. These groups also show different proper motions. This suggests that the star-forming scenario in this region is more complex than the traditional spatial-temporal scenario, in which a generation of stars triggers the formation of a new spatially differentiated generation of stars.

This document addresses the Nurse Scheduling Problem (NSP) and presents a dynamic multi-criteria optimization model for its solution considering a predefined time horizon. The purpose is to maximize the level of work of nurses formulated as the minimization of which translates into costs or penalties for certain undesirable work shifts. For this, a series of criteria are defined to estimate the preference structure of nurses according to the hospital center specifications by assigning costs for undesirable shift assignments. The proposed methodology involves developing a heuristic to decompose the global problem into daily subproblems for which a dynamic algorithm is implemented that considers a cost accumulation process for all criteria and all nurses. Daily models are dynamically solved by modifying the coefficients of the well-being function to achieve equity throughout the planning period by updating and accumulating different averages. This methodology has shown satisfactory results for scheduling work shifts for doctors, paramedics, security guards, and drivers in numerous hospital centers in Colombia.

We present a variability and morphological classification study of TESS light curves for T Tauri star candidates in the Orion, IC 348, γ Velorum, Upper Scorpius, Corona Australis, and Perseus OB2 regions. We propose 11 morphological classes linking brightness variation behaviors with possible physical or geometric phenomena present in T Tauri stars, and develop a supervised machine-learning algorithm to automate the classification among these. Our algorithm optimizes and compares the true positive rate (recall) among k-nearest neighbors, classification trees, random forests, and support vector machines. This is done characterizing light curves with features depending on time, periodicity, and magnitude distribution. Binary and multiclass classifiers are trained and interpreted in a way that allows our final algorithm to have single or mixed classes. In the testing sample, the algorithm assigns mixed classes to 27% of the stars, reaching up to five simultaneous classes. A catalog of 3672 T Tauri star candidates is presented, along with their possible period estimations, predicted morphological classes, and visually revised ones. The cross-validation estimated performance of the final classifiers is reported. Binary classifiers surpass multiclass recall values for classes with less representation in the training sample. Support vector machines and random forest classifiers obtain better recalls. For comparison, another performance estimation of the final classifiers is calculated using the revised classes of our testing sample, indicating that this performance excels in singled classed stars, which happens in about 75% of the testing sample.

The proliferation of high time resolution and decades-long monitoring of classical T Tauri stars provides a vast opportunity to test the variability of star–disk connections. However, most monitoring surveys use single broadband filters, which makes the conversion of photometric variability into accretion rate difficult. In this study, we analyze accretion bursts onto the nearby young star TW Hya over short (hours, days) and long (months, years) timescales by calibrating Transiting Exoplanet Survey Satellite (TESS) and All-Sky Automated Survey for Supernovae (ASAS-SN) g-band photometry to accretion rates with simultaneous spectroscopy. The high-cadence TESS light curve shows bursts of accretion in clumps with masses from a sensitivity limit of ∼10−13 M⊙ up to 3 × 10−11 M⊙. The average burst duration of 1.8 days is longer than a simple estimate of the thermal response timescale, supporting the interpretation that the photometric variability probes the instantaneous accretion rate. The reset timescale of 1.2–2 days derived from the structure function and previously reported quasi-periods of 3.5–4 days are consistent with bursts that may be related to the different rotation between the stellar magnetosphere and inner disk or with azimuthal asymmetries in the inner disk. The near-daily ASAS-SN light curve across 8 yr reveals some seasonal changes in brightness with a standard deviation of ∼0.13 mag, about half of the scatter seen on short timescales. This study demonstrates the importance of coordinating contemporaneous multiepoch spectroscopy with time domain surveys to interpret light curves of young stars.