615 research outputs found
Low temperature mean opacities for the carbon-rich regime
Asymptotic Giant Branch (AGB) stars undergo a change in their chemical
composition during their evolution. This in turn leads to an alteration of the
radiative opacities, especially in the cool layers of the envelope and the
atmosphere, where molecules are the dominant opacity sources. A key parameter
in this respect is the number ratio of carbon to oxygen atoms (C/O). In terms
of low temperature mean opacities, a variation of this parameter usually cannot
be followed in stellar evolution models, because up to now tabulated values
were only available for scaled solar metal mixtures (with C/O ~ 0.5). We thus
present a set of newly generated tables containing Rosseland mean opacity
coefficients covering both the oxygen-rich (C/O
1) regime. We compare our values to existing tabular data and investigate the
relevant molecular opacity contributors.Comment: 8 pages, 5 figures. To appear in the AIP Proceedings of the IXth
Torino Workshop on AGB Nucleosynthesi
Mobility recorded by wearable devices and gold standards: the Mobilise-D procedure for data standardization
Wearable devices are used in movement analysis and physical activity research to extract clinically relevant information about an individual’s mobility. Still, heterogeneity in protocols, sensor characteristics, data formats, and gold standards represent a barrier for data sharing, reproducibility, and external validation. In this study, we aim at providing an example of how movement data (from the real-world and the laboratory) recorded from different wearables and gold standard technologies can be organized, integrated, and stored. We leveraged on our experience from a large multi-centric study (Mobilise-D) to provide guidelines that can prove useful to access, understand, and re-use the data that will be made available from the study. These guidelines highlight the encountered challenges and the adopted solutions with the final aim of supporting standardization and integration of data in other studies and, in turn, to increase and facilitate comparison of data recorded in the scientific community. We also provide samples of standardized data, so that both the structure of the data and the procedure can be easily understood and reproduced
Low-mass lithium-rich AGB stars in the Galactic bulge: evidence for Cool Bottom Processing?
Context: The stellar production of the light element lithium is still a
matter of debate.
Aims: We report the detection of low-mass, Li-rich Asymptotic Giant Branch
(AGB) stars located in the Galactic bulge.
Methods: A homogeneous and well-selected sample of low mass, oxygen-rich AGB
stars in the Galactic bulge has been searched for the absorption lines of Li.
Using spectral synthesis techniques, we determine from high resolution UVES/VLT
spectra the Li abundance in four out of 27 sample stars, and an upper limit for
the remaining stars.
Results: Two stars in our sample have a solar Li abundance or above; these
stars seem to be a novelty, since they do not show any s-element enhancement.
Two more stars have a Li abundance slightly below solar; these stars do show
s-element enhancement in their spectra. Different scenarios which lead to an
increased Li surface abundance in AGB stars are discussed.
Conclusions: Of the different enrichment scenarios presented, Cool Bottom
Processing (CBP) is the most likely one for the Li-rich objects identified
here. Self-enrichment by Hot Bottom Burning (HBB) seems very unlikely as all
Li-rich stars are below the HBB mass limit. Also, the ingestion of a low mass
companion into the stars' envelope is unlikely because the associated
additional effects are lacking. Mass transfer from a former massive binary
companion is a possible scenario, if the companion produced little s-process
elements. A simple theoretical estimation for the Li abundance due to CBP is
presented and compared to the observed values.Comment: 5 pages, 3 figures, accepted by A&A Letter
Protocol for the DeFOG trial: A randomized controlled trial on the effects of smartphone-based, on-demand cueing for freezing of gait in Parkinson's disease
Background: Freezing of gait (FOG) is a highly incapacitating symptom that affects many people with Parkinson's disease (PD). Cueing triggered upon real-time FOG detection (on-demand cueing) shows promise for FOG treatment. Yet, the feasibility of implementation and efficacy in daily life is still unknown. Therefore, this study aims to investigate the effectiveness of DeFOG: a smartphone and sensor-based on-demand cueing solution for FOG. Methods: Sixty-two PD patients with FOG will be recruited for this single-blind, multi-center, randomized controlled phase II trial. Patients will be randomized into either the intervention group or the active control group. For four weeks, both groups will receive feedback about their physical activity using the wearable DeFOG system in daily life. In addition, the intervention group will also receive on-demand auditory cueing and instructions. Before and after the intervention, home-based assessments will be performed to evaluate the primary outcome, i.e., “percentage time frozen” during a FOG-provoking protocol. Secondary outcomes include the training effects on physical activity monitored over 7 days and the user-friendliness of the technology. Discussion: The DeFOG trial will investigate the effectiveness of personalized on-demand cueing in a controlled design, delivered for 4 weeks in the patient's home environment. We anticipate that DeFOG will reduce FOG to a greater degree than in the control group and we will explore the impact of the intervention on physical activity levels. We expect to gain in-depth insight into whether and how patients control FOG using cueing methods in their daily lives. Trial registration: Clinicaltrials.gov NCT03978507
Lithium abundances along the RGB: FLAMES-GIRAFFE spectra of a large sample of low-mass Bulge stars
Context: A small number of K-type giants on the red giant branch (RGB) is
known to be very rich in lithium (Li). This fact is not accounted for by
standard stellar evolution theory. The exact phase and mechanism of Li
enrichment is still a matter of debate. Aims: Our goal is to probe the
abundance of Li along the RGB, from its base to the tip, to confine Li-rich
phases that are supposed to occur on the RGB. Methods: For this end, we
obtained medium-resolution spectra with the FLAMES spectrograph at the VLT in
GIRAFFE mode for a large sample of 401 low-mass RGB stars located in the
Galactic bulge. The Li abundance was measured in the stars with a detectable Li
670.8 nm line by means of spectral synthesis with COMARCS model atmospheres. A
new 2MASS (J-K) - Teff calibration from COMARCS models is presented in the
Appendix. Results: Thirty-one stars with a detectable Li line were identified,
three of which are Li-rich according to the usual criterion (). The stars are distributed all along the RGB, not concentrated in
any particular phase of the red giant evolution (e.g. the luminosity bump or
the red clump). The three Li-rich stars are clearly brighter than the
luminosity bump and red clump, and do not show any signs of enhanced mass loss.
Conclusions: We conclude that the Li enrichment mechanism cannot be restricted
to a clearly defined phase of the RGB evolution of low-mass stars
(M\sim1M_{\sun}), contrary to earlier suggestions from disk field stars.Comment: 6 pages (14 with appendix), 5 figures (1 in appendix), accepted for
publication in A&
Algorithms for walking speed estimation using a lower-back-worn inertial sensor: A cross-validation on speed ranges
Walking/gait speed is a key measure for daily mobility characterization. To date, various studies have attempted to design algorithms to estimate walking speed using an inertial sensor worn on the lower back, which is considered as a proper location for activity monitoring in daily life. However, these algorithms were rarely compared and validated on the same datasets, including people with different preferred walking speed. This study implemented several original, improved, and new algorithms for estimating cadence, step length and eventually speed. We designed comprehensive cross-validation to compare the algorithms for walking slow, normal, fast, and using walking aids. We used two datasets, including reference data for algorithm validation from an instrumented mat (40 subjects) and shanks-worn inertial sensors (88 subjects), with normal and impaired walking patterns. The results showed up to 50% performance improvements. Training of algorithms on data from people with different preferred speeds led to better performance. For the slow walkers, an average RMSE of 2.5 steps/min, 0.04 m, and 0.10 m/s were respectively achieved for cadence, step length, and speed estimation. For normal walkers, the errors were 3.5 steps/min, 0.08 m, and 0.12 m/s. An average RMSE of 1.3 steps/min, 0.05 m, and 0.10 m/s were also observed on fast walkers. For people using walking aids, the error significantly increased up to an RMSE of 14 steps/min, 0.18 m, and 0.27 m/s. The results demonstrated the robustness of the proposed combined speed estimation approach for different speed ranges. It achieved an RMSE of 0.10, 0.18, 0.15, and 0.32 m/s for slow, normal, fast, and using walking aids, respectively
Revascularization for Unprotected Left Main Coronary Artery Disease: An Evolution in Clinical Decision Making
Coronary artery bypass grafting (CABG) has been considered the standard therapy for unprotected (nonrevascularized) left main coronary disease (ULM). However, increasing experience with ULM percutaneous coronary intervention (PCI) has resulted in high procedural success and favorable early and late clinical outcomes. In particular, reduction in clinical restenosis with drug-eluting stents, evolution of procedural technique, and demonstration of favorable outcomes from comparative trials with CABG have promoted consideration of PCI as an alternative revascularization strategy in selected patients with ULM disease. This review summarizes the results from comparative studies examining PCI versus CABG for ULM disease, discusses changing indications for ULM PCI and identifies outstanding issues that must be considered before further advancing treatment recommendations
Tumoral immune-infiltrate (IF), PD-L1 expression and role of CD8/TIA-1 lymphocytes in localized osteosarcoma patients treated within protocol ISG-OS1
Background: We hypothesized that immune-infiltrates were associated with superior survival, and examined a primary osteosarcoma tissue microarrays (TMAs) to test this hypothesis.
Methods: 129 patients (pts) with localized osteosarcoma treated within protocol ISG-OS1 were included in the study. Clinical characteristics, expression of CD8, CD3, FOXP3, CD20, CD68/CD163 (tumor associated macrophage, TAM), Tia-1 (cytotoxic T cell), CD303 (plasmacytoid dendritic cells: pDC), Arginase-1 (myeloid derived suppressor cells: MDSC), PD-1 on immune-cells (IC), and PD-L1 on tumoral cells (TC) and IC were analysed and correlated with outcome.
Results: Most of the cases presented tumor infiltrating lymphocytes (TILs) (CD3+ 90%; CD8+ 86%). Tia-1 was detected in 73% of the samples. PD-L1 expression was found in 14% patients in IC and 0% in TC; 22% showed PD-1 expression in IC.
With a median follow-up of 8 years (range 1-13), the 5-year overall survival (5-year OS) was 74% (95% CI 64-85). Univariate analysis showed better 5-year OS for: a) pts with a good histologic response to neoadjuvant chemotherapy (p = 0.0001); b) pts with CD8/Tia1 tumoral infiltrates (p = 0.002); c) pts with normal alkaline phosphatas (sALP) (p = 0.04). After multivariate analysis, histologic response (p = 0.007) and CD8/Tia1 infiltration (p = 0.01) were independently correlated with survival. In the subset of pts with CD8+ infiltrate, worse (p 0.02) OS was observed for PD-L1(IC)+ cases.
Conclusions: Our findings support the hypothesis that CD8/Tia1 infiltrate in tumor microenvironment at diagnosis confers superior survival for pts with localized osteosarcoma, while PD-L1 expression is associated with worse survival
Trabectedin for patients with advanced soft tissue sarcoma: A non-interventional, retrospective, multicenter study of the italian sarcoma group
The Italian Sarcoma Group performed this retrospective analysis of patients with advanced soft tissue sarcoma, pretreated with ≥1 anthracycline-based treatment, and treated with trabectedin every three weeks. Primary endpoint was to describe real-life use of trabectedin across Italy. Secondary endpoints included objective response rate (ORR) and safety. Overall, 512 patients from 20 Italian centers were evaluated. Leiomyosarcoma (37.7%)/liposarcoma (30.3%) were the most prevalent histological types (abbreviated as L-sarcoma). Patients received a median of four trabectedin cycles (range: 1–40), mostly as a second-line treatment (~60% of patients). The ORR was 13.7% superior (p < 0.0001) in patients with L-sarcoma compared with patients with non-L-sarcoma (16.6% vs. 9.0%). Median progression-free survival (PFS) was 5.1 months, whereas median overall survival (OS) was 21.6 months. Significantly better PFS and OS were observed in patients with L-sarcoma, those with objective responses and/or disease stabilization, treated in an early line and treated with reduced dose. Bone marrow toxicity (61.4%) and transaminase increases (21.9%) were the most common grade 3/4 adverse events. The results of this real-life study suggest that trabectedin is an active treatment, which is mostly given as a second-line treatment to patients with a good performance status and high-grade, metastatic L-sarcoma (clinical trial information: NCT02793050)
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