| 1. |
- Mohandasan, Anjana, et al.
(författare)
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Photometric binaries in 14 Magellanic Cloud star clusters
- 2024
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 681
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Tidskriftsartikel (refereegranskat)abstract
- Binary stars play a major role in determining the dynamic evolution of star clusters. We used images collected with the Hubble Space Telescope to study fourteen star clusters of the Magellanic Clouds that span an age interval between ∼0.6 and 2.1 Gyr and masses of 104 − 105 M⊙. We estimated the fraction of binary systems composed of two main-sequence stars and the fraction of candidate blue-straggler stars (BSSs). Moreover, we derived the structural parameters of the cluster, including the core radius, central density, mass function, and total mass. We find that the fraction of binaries with a mass ratio larger than 0.7 ranges from ∼7% in NGC 1846 to ∼20% in NGC 2108. The radial and luminosity distribution can change from one cluster to another. However, when we combine the results from all the clusters, we find that binaries follow a flat radial trend and no significant correlation with the mass of the primary star. We find no evidence for a relation between the fractions of binaries and BSSs. We combined the results on binaries in the studied Magellanic Cloud clusters with those obtained for 67 Galactic globular clusters and 78 open clusters. We detect a significant anti-correlation between the binary fraction in the core and the mass of the host cluster. However, star clusters with similar masses exhibit a wide range of binary fractions. Conversely, there is no evidence of a correlation between the fraction of binaries and the cluster age or the dynamic age.
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| 3. |
- Raufer, Stefan, et al.
(författare)
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Anatomy of the Human Osseous Spiral Lamina and Cochlear Partition Bridge: Relevance for Cochlear Partition Motion
- 2020
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Ingår i: Journal of the Association for Research in Otolaryngology. - : SPRINGER. - 1525-3961 .- 1438-7573. ; 21:2, s. 171-182
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Tidskriftsartikel (refereegranskat)abstract
- The classic view of cochlear partition (CP) motion, generalized to be for all mammals, was derived from basal-turn measurements in laboratory animals. Recently, we reported motion of the human CP in the cochlear base that differs substantially from the classic view. We described a human soft tissue "bridge" (non-existent in the classic view) between the osseous spiral lamina (OSL) and basilar membrane (BM), and showed how OSL and bridge move in response to sound. Here, we detail relevant human anatomy to better understand the relationship between form and function. The bridge and BM have similar widths that increase linearly from base to apex, whereas the OSL width decreases from base to apex, leading to an approximately constant total CP width throughout the cochlea. The bony three-dimensional OSL microstructure, reconstructed from unconventionally thin, 2-mu m histological sections, revealed thin, radially wide OSL plates with pores that vary in size, extent, and distribution with cochlear location. Polarized light microscopy revealed collagen fibers in the BM that spread out medially through the bridge to connect to the OSL. The long width and porosity of the OSL may explain its considerable bending flexibility. The similarity of BM and bridge widths along the cochlea, both containing continuous collagen fibers, may make them a functional unit and allow maximum CP motion near the bridge-BM boundary, as recently described. These anatomical findings may help us better understand the motion of the structures surrounding the organ of Corti and how they shape the input to the cochlear sensory mechanism.
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