| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Crowe, S., et al.
(författare)
-
Near-infrared observations of outflows and young stellar objects in the massive star-forming region AFGL 5180
- 2024
-
Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 682
-
Tidskriftsartikel (refereegranskat)abstract
- Context. Massive stars play important roles throughout the universe; however, their formation remains poorly understood. Observations of jets and outflows in high-mass star-forming regions, as well as surveys of young stellar object (YSO) content, can help test theoretical models of massive star formation. Aims. We aim at characterizing the massive star-forming region AFGL 5180 in the near-infrared (NIR), identifying outflows and relating these to sub-mm/mm sources, as well as surveying the overall YSO surface number density to compare to massive star formation models. Methods. Broad- and narrow-band imaging of AFGL 5180 was made in the NIR with the Large Binocular Telescope, in both seeing-limited (~0.5′) and high angular resolution (~0.09′) Adaptive Optics (AO) modes, as well as with the Hubble Space Telescope. Archival continuum data from the Atacama Millimeter/Submillimeter Array (ALMA) was also utilized. Results. At least 40 jet knots were identified via NIR emission from H2 and [FeII] tracing shocked gas. Bright jet knots outflowing from the central most massive protostar, S4 (estimated mass ~11 M⊙, via SED fitting), are detected towards the east of the source and are resolved in fine detail with the AO imaging. Additional knots are distributed throughout the field, likely indicating the presence of multiple driving sources. Sub-millimeter sources detected by ALMA are shown to be grouped in two main complexes, AFGL 5180 M and a small cluster ~15′ (0.15 pc in projection) to the south, AFGL 5180 S. From our NIR continuum images we identify YSO candidates down to masses of ~0.1 M⊙. Combined with the sub-mm sources, this yields a surface number density of such YSOs of N* ~ 103pc-2 within a projected radius of about 0.1 pc. Such a value is similar to those predicted by models of both core accretion from a turbulent clump environment and competitive accretion. The radial profile of N* is relatively flat on scales out to 0.2 pc, with only modest enhancement around the massive protostar inside 0.05 pc, which provides additional constraints on these massive star formation models. Conclusions. This study demonstrates the utility of high-resolution NIR imaging, in particular with AO, for detecting outflow activity and YSOs in distant regions. The presented images reveal the complex morphology of outflow-shocked gas within the large-scale bipolar flow of a massive protostar, as well as clear evidence for several other outflow driving sources in the region. Finally, this work presents a novel approach to compare the observed YSO surface number density from our study against different models of massive star formation.
|
|
| 5. |
- Zhang, Y. T., et al.
(författare)
-
Predicting AT(N) pathologies in Alzheimer's disease from blood-based proteomic data using neural networks
- 2022
-
Ingår i: Frontiers in Aging Neuroscience. - : Frontiers Media SA. - 1663-4365. ; 14
-
Tidskriftsartikel (refereegranskat)abstract
- Background and objective: Blood-based biomarkers represent a promising approach to help identify early Alzheimer's disease (AD). Previous research has applied traditional machine learning (ML) to analyze plasma omics data and search for potential biomarkers, but the most modern ML methods based on deep learning has however been scarcely explored. In the current study, we aim to harness the power of state-of-the-art deep learning neural networks (NNs) to identify plasma proteins that predict amyloid, tau, and neurodegeneration (AT[N]) pathologies in AD.Methods: We measured 3,635 proteins using SOMAscan in 881 participants from the European Medical Information Framework for AD Multimodal Biomarker Discovery study (EMIF-AD MBD). Participants underwent measurements of brain amyloid 13 (A13) burden, phosphorylated tau (p-tau) burden, and total tau (t-tau) burden to determine their AT(N) statuses. We ranked proteins by their association with A13, p-tau, t-tau, and AT(N), and fed the top 100 proteins along with age and apolipoprotein E (APOE) status into NN classifiers as input features to predict these four outcomes relevant to AD. We compared NN performance of using proteins, age, and APOE genotype with performance of using age and APOE status alone to identify protein panels that optimally improved the prediction over these main risk factors. Proteins that improved the prediction for each outcome were aggregated and nominated for pathway enrichment and protein-protein interaction enrichment analysis.Results: Age and APOE alone predicted A13, p-tau, t-tau, and AT(N) burden with area under the curve (AUC) scores of 0.748, 0.662, 0.710, and 0.795. The addition of proteins significantly improved AUCs to 0.782, 0.674, 0.734, and 0.831, respectively. The identified proteins were enriched in five clusters of AD-associated pathways including human immunodeficiency virus 1 infection, p53 signaling pathway, and phosphoinositide-3-kinase-protein kinase B/Akt signaling pathway.Conclusion: Combined with age and APOE genotype, the proteins identified have the potential to serve as blood-based biomarkers for AD and await validation in future studies. While the NNs did not achieve better scores than the support vector machine model used in our previous study, their performances were likely limited by small sample size.
|
|
| 6. |
- Zurlo, A., et al.
(författare)
-
Orbital and dynamical analysis of the system around HR 8799 New astrometric epochs from VLT/SPHERE and LBT/LUCI
- 2022
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 666
-
Tidskriftsartikel (refereegranskat)abstract
- Context. HR 8799 is a young planetary system composed of four planets and a double debris belt. Being the first multi-planetary system discovered with the direct imaging technique, it has been observed extensively since 1998. This wide baseline of astrometric measurements, counting over 50 observations in 20 years, permits a detailed orbital and dynamical analysis of the system.Aims. To explore the orbital parameters of the planets, their dynamical history, and the planet-to-disk interaction, we made follow-up observations of the system during the VLT/SPHERE guaranteed time observation program. We obtained 21 observations, most of them in favorable conditions. In addition, we observed HR 8799 with the instrument LUCI at the Large Binocular Telescope (LBT).Methods. All the observations were reduced with state-of-the-art algorithms implemented to apply the spectral and angular differential imaging method. We re-reduced the SPHERE data obtained during the commissioning of the instrument and in three open-time programs to have homogeneous astrometry. The precise position of the four planets with respect to the host star was calculated by exploiting the fake negative companions method. We obtained an astrometric precision of the order of 6 mas in the worst case and 1 mas in the best case. To improve the orbital fitting, we also took into account all of the astrometric data available in the literature. From the photometric measurements obtained in different wavelengths, we estimated the masses of the planets following the evolutionary models.Results. We obtained updated parameters for the orbits with the assumption of coplanarity, relatively small eccentricities, and periods very close to the 2:1 resonance. We also refined the dynamical mass of each planet and the parallax of the system (24.49 ± 0.07 mas), which overlap with the recent Gaia eDR3/DR3 estimate. Hydrodynamical simulations suggest that inward migration of the planets caused by the interaction with the disk might be responsible for the planets being locked in resonance. We also conducted detailed N-body simulations indicating possible positions of a putative fifth planet with a mass below the present detection limits of ≃3 MJup.
|
|
| 7. |
- El-Khatib, Z, et al.
(författare)
-
Patterns and Predictors of Insufficient Antenatal Care Utilization in Nigeria over a Decade: A Pooled Data Analysis Using Demographic and Health Surveys
- 2020
-
Ingår i: International journal of environmental research and public health. - : MDPI AG. - 1660-4601. ; 17:21
-
Tidskriftsartikel (refereegranskat)abstract
- This study investigated the patterns of antenatal care (ANC) utilization and insufficient use of ANC as well as its association with some proximate socio-demographic factors. This was a cross-sectional study using pooled data Nigeria Demographic and Health Surveys from years 2008, 2013 and 2018. Participants were 52,654 women of reproductive age who reported at least one birth in the five years preceding the surveys. The outcome variables were late attendance, first contact after first trimester and less than four antenatal visits using multivariable logistic regression analysis. The overall prevalence of late timing was 74.8% and that of insufficient ANC visits was 46.7%. In the multivariable regression analysis; type of residency, geo-political region, educational level, household size, use of contraceptives, distance to health service, exposure to the media and total number of children were found to be significantly associated with both late and insufficient ANC attendance. About half of the pregnant women failed to meet the recommendation of four ANC visits. Investing on programs to improve women’s socio-economic status, addressing the inequities between urban and rural areas of Nigeria in regard to service utilization, and controlling higher fertility rates may facilitate the promotion of ANC service utilization in Nigeria.
|
|
| 8. |
|
|
