The shortest period M-dwarf eclipsing system BW3 V38, II: determination of absolute elements

The spectroscopic data for the short-period (0.1984 d)eclipsing binary V38, discovered by the OGLE micro-lensing team in Baade's Window field BW3, are analyzed. Radial velocity curves are derived from mid-resolution spectra obtained with EMMI-NTT at ESO - La Silla, and a simultaneous solution of the existing light curve by OGLE and of the new radial velocity curves is obtained. The system is formed by almost twin M3e dwarf components that are very close, but not yet in contact. The spectra of both dwarfs show signatures of the presence of strong chromospheres. Spectroscopy definitely confirms, therefore, what was suggested on the basis of photometry: BW3 V38 is indeed a unique system, as no other similar binary with M components and in such a tight orbit is known. Within the limits posed by the relatively large errors, due to the combined effect of system faintness and of the constraints on exposure time, the derived physical parameters seem to agree with the relations obtained from the other few known eclipsing binaries with late type components (which indicate a discrepancy between the available evolutionary models and the data at ~ 10% level). A possible explanation is the presence of strong magnetic fields and fast rotation (that applies to the BW3 V38 case as well). A simple computation of the system secular evolution by angular momentum loss and spin orbit synchronization shows that the evolution of a system with M dwarfs components is rather slow, and indicates as well a possible reason why systems similar to BW3 V38 are so rare.Comment: 9 pages, 7 figures, 3 tables, accepted for publication in A&

A-type stars: evolution, rotation and binarity

We discuss the internal structure of stars in the mass range 1.5 to 4 M_sun from the PMS to the subgiant phase with a particular emphasis on the convective core and the convective superficial layers. Different physical aspects are considered such as overshooting, treatment of convection, microscopic diffusion and rotation. Their influence on the internal structure and on the photospheric chemical abundances is briefly described. The role of binarity in determining the observed properties and as a tool to constrain the internal structure is also introduced and the current limits of theories of orbital evolution and of available binary data--sets are discussed. keywords{stars: evolution, stars: binaries: general, stars: rotation}Comment: 11 pages, 7 figures, conference: The A-star Puzzle, IAU Simp. 224, 200

Precision Masses of the low-mass binary system GJ 623

We have used Aperture Masking Interferometry and Adaptive Optics (AO) at the Palomar 200'' to obtain precise mass measurements of the binary M dwarf GJ 623. AO observations spread over 3 years combined with a decade of radial velocity measurements constrain all orbital parameters of the GJ 623 binary system accurately enough to critically challenge the models. The dynamical masses measured are m_{1}=0.371\pm0.015 M_{\sun} (4%) and m_{2}=0.115\pm0.0023 M_{\sun} (2%) for the primary and the secondary respectively. Models are not consistent with color and mass, requiring very low metallicities.Comment: 7 pages, 5 figures. Accepted for Ap

Network Selection Over 5G-Advanced Heterogeneous Networks Based on Federated Learning and Cooperative Game Theory

5G-Advanced and Beyond claims a 3D ecosystem with cooperation between terrestrial and non-terrestrial networks to achieve seamless coverage, improve capacity, and enable advanced applications with strict quality of service (QoS) requirements. This complex environment requires a disaggregated Radio Access Network (RAN) deployment with open interfaces, such as the architecture promoted by the O-RAN Alliance. This architecture, supporting the slicing paradigm, is a prominent solution to guarantee dynamism and differentiated traffic management. Furthermore, intelligence is critical for future wireless networks to enable Machine Learning (ML)-based optimization for autonomous RANs, handling ultra-dense heterogeneous environments, and adapting to numerous scenarios. This paper presents an enhanced Dynamic Radio Access Network Selection (eDRANS) algorithm based on Federated Double Deep Q-Network (F-DDQN) and inserted in the novel O-RAN architecture. The proposal selects the most suitable base station (BS) to satisfy multiple service requests, optimizing QoS and slicing resource utilization. Moreover, the solution employs a Cooperative Game Theory (CGT) approach to manage resources in overload situations. This load-balancing process enables the acceptance of new clients without abruptly degrading the active users' perception. eDRANS is adapted to diverse network conditions, multiple service constraints, and several user types with different priorities and mobility behaviors. The proposal is validated through network-level simulations, recreating a heterogeneous environment composed of terrestrial-airborne nodes and using the Max-SINR criterion, a heuristic algorithm, and centralized and distributed ML solutions as benchmarks. Results show that eDRANS correctly learns during multiple trial-and-error interactions with the environment, fulfilling the Service Level Agreement (SLA) and maximizing user satisfaction

Progressive MS trials: Lessons learned.

Up to very recently, no treatments had proved effective in progressive multiple sclerosis (MS). In 2016, four drugs, two tested in phase 3 and two in phase 2 trials, showed a beneficial effect in primary or secondary progressive MS. Although this could indicate a turning point in progressive MS treatment, most of these successes have been modest and mainly restricted to patients with active inflammation, in the context of trials with powerful anti-inflammatory agents. This paper summarises these reasons, particularly focusing on the main lessons learned for the design of future trials. First, a drug’s mechanism of action should tackle the specific pathogenic mechanisms that characterise progressive MS. Second, trial populations where new drugs are to be tested should be carefully chosen, possibly including younger patients with shorter disease durations, which have greater chances of showing active deterioration during the trial, therefore increasing the power to detect treatment effects. Third, outcome measures used in future phase 2 and phase 3 trials should be highly sensitive and be accompanied by smart trial designs

Non-radial oscillations in the red giant HR7349 measured by CoRoT

Convection in red giant stars excites resonant acoustic waves whose frequencies depend on the sound speed inside the star, which in turn depends on the properties of the stellar interior. Therefore, asteroseismology is the most robust available method for probing the internal structure of red giant stars. Solar-like oscillations in the red giant HR7349 are investigated. Our study is based on a time series of 380760 photometric measurements spread over 5 months obtained with the CoRoT satellite. Mode parameters were estimated using maximum likelihood estimation of the power spectrum. The power spectrum of the high-precision time series clearly exhibits several identifiable peaks between 19 and 40 uHz showing regularity with a mean large and small spacing of Dnu = 3.47+-0.12 uHz and dnu_02 = 0.65+-0.10 uHz. Nineteen individual modes are identified with amplitudes in the range from 35 to 115 ppm. The mode damping time is estimated to be 14.7+4.7-2.9 days.Comment: 8 pages, A&A accepte

Artificial Intelligence Aided Low Complexity RRM Algorithms for 5G-MBS

For the upcoming 5G-Advanced, the multicast/broadcast services (5G-MBS) capability is one of the most appealing use cases. The effective integration of point-to-multipoint communication will address the ever-growing traffic demands, disruptive multimedia services, massive connectivity, and low-latency applications. This paper proposes novel approaches for the dynamic access technique selection and resource allocation for multicast groups (MGs) subject to the 5G-MBS paradigm. Our proposal is oriented to address and contextualize the complexity associated with multicast radio resource management (RRM) and the implications of fast variations in the reception conditions of the MG members. We propose a solution structured by a multicast-oriented trigger to avoid overrunning the algorithm, a K-means clustering for group-oriented detection and splitting, a classifier for selecting the most suitable multicast access technique, and a final resource allocation algorithm. To choose the multicast access technique that better fits the specific reception conditions of the users, we evaluate heuristic strategies and machine learning (ML) multiclass classification solutions. We consider the conventional multicast scheme (MCS) and subgrouping based on orthogonal/non-orthogonal multiplex access (OMA/NOMA) as access techniques. We assess the effectiveness of our solution in terms of the quality of service (QoS) parameters and complexity. The proposed technical solution is validated through extensive simulation for a single-cell 5G-MBS use case in the microwave (\mu Wave) and millimeter wave (mmWave) band with different mobility behaviors

Effect of Evobrutinib on Slowly Expanding Lesion Volume in Relapsing Multiple Sclerosis: A Post Hoc Analysis of a Phase 2 Trial

Evobrutinib; Lesion; Relapsing multiple sclerosisEvobrutini; Lesión; Esclerosis múltiple recurrenteEvobrutinib; Lesió; Esclerosi múltiple recurrentBackground and Objectives Chronic active lesions (CALs) are demyelinated multiple sclerosis (MS) lesions with ongoing microglia/macrophage activity, resulting in irreversible neuronal damage and axonal loss. Evobrutinib is a highly selective, covalent, CNS-penetrant, Bruton tyrosine kinase inhibitor. This post hoc analysis evaluated the effect of evobrutinib on slowly expanding lesion (SEL) volume, an MRI marker of CALs, assessed baseline–week 48 in a phase 2, double-blind, randomized trial (NCT02975349) in relapsing MS (RMS). Methods In the 48-week, double-blind trial, adult patients received evobrutinib (25 mg once daily [QD], 75 mg QD, or 75 mg twice daily [BID]), placebo (switched to evobrutinib 25 mg QD after week 24), or open-label dimethyl fumarate (DMF) 240 mg BID. SELs were defined as slowly and consistently radially expanding areas of preexisting T2 lesions of ≥10 contiguous voxels (∼30 mm3) over time. SELs were identified by MRI and assessed by the Jacobian determinant of the nonlinear deformation from baseline to week 48. SEL volume analysis, stratified by baseline T2 lesion volume tertiles, was based on week 48/end-of-treatment status (completers/non-completers). Treatment effect was analyzed using the stratified Hodges-Lehmann estimate of shift in distribution and stratified Wilcoxon rank-sum test. Comparisons of evobrutinib and DMF vs placebo/evobrutinib 25 mg QD were made. Subgroup analyses used pooled treatment groups (evobrutinib high dose [75 mg QD/BID] vs low dose [placebo/evobrutinib 25 mg QD]). Results The SEL analysis set included 223 patients (mean [SD] age: 42.4 [10.7] years; 69.3% female; 87.4% relapsing/remitting MS). Mean (SD) SEL volume was 2,099 (2,981.0) mm3 with evobrutinib 75 mg BID vs 2,681 (3,624.2) mm3 with placebo/evobrutinib 25 mg QD. Median number of SELs/patient ranged from 7 to 11 across treatments. SEL volume decreased with increasing evobrutinib dose vs placebo/evobrutinib 25 mg QD, and no difference with DMF vs placebo/evobrutinib 25 mg QD was noted. SEL volume significantly decreased with evobrutinib 75 mg BID vs placebo/evobrutinib 25 mg QD (−474.5 mm3 [−1,098.0 to −3.0], p = 0.047) and vs DMF (−711.6 [−1,290.0 to −149.0], p = 0.011). SEL volume was significantly reduced for evobrutinib high vs low dose within baseline Expanded Disability Status Scale ≥3.5 and longer disease duration (≥8.5 years) subgroups. Discussion Evobrutinib reduced SEL volume in a dose-dependent manner in RMS, with a significant reduction with evobrutinib 75 mg BID. This is evident that evobrutinib affects brain lesions associated with chronic inflammation and tissue loss. Trial Registration Information ClinicalTrials.gov number: NCT02975349. Submitted to ClinicalTrials.gov on November 29, 2016. First patient enrolled: March 7, 2017. Classification of Evidence This study provides Class II evidence that evobrutinib reduces the volume of SELs assessed on MRI comparing baseline with week 48, in patients with RMS.The trial was sponsored by the healthcare business of Merck KGaA, Darmstadt, Germany (CrossRef Funder ID: 10.13039/100009945)

T2 lesion location really matters: a 10 year follow-up study in primary progressive multiple sclerosis

Objectives: Prediction of long term clinical outcome in patients with primary progressive multiple sclerosis (PPMS) using imaging has important clinical implications, but remains challenging. We aimed to determine whether spatial location of T2 and T1 brain lesions predicts clinical progression during a 10-year follow-up in PPMS. Methods: Lesion probability maps of the T2 and T1 brain lesions were generated using the baseline scans of 80 patients with PPMS who were clinically assessed at baseline and then after 1, 2, 5 and 10 years. For each patient, the time (in years) taken before bilateral support was required to walk (time to event (TTE)) was used as a measure of progression rate. The probability of each voxel being ‘lesional’ was correlated with TTE, adjusting for age, gender, disease duration, centre and spinal cord cross sectional area, using a multiple linear regression model. To identify the best, independent predictor of progression, a Cox regression model was used. Results: A significant correlation between a shorter TTE and a higher probability of a voxel being lesional on T2 scans was found in the bilateral corticospinal tract and superior longitudinal fasciculus, and in the right inferior fronto-occipital fasciculus (p<0.05). The best predictor of progression rate was the T2 lesion load measured along the right inferior fronto-occipital fasciculus (p=0.016, hazard ratio 1.00652, 95% CI 1.00121 to 1.01186). Conclusion: Our results suggest that the location of T2 brain lesions in the motor and associative tracts is an important contributor to the progression of disability in PPMS, and is independent of spinal cord involvement