Seismic evolution of low/intermediate mass PMS stars

This article presents a study of the evolution of the internal structure and seismic properties expected for low/intermediate mass Pre-Main Sequence (PMS) stars. Seismic and non-seismic properties of PMS stars were analysed. This was done using 0.8 to 4.4M$_\odot$ stellar models at stages ranging from the end of the Hayashi track up to the Zero-Age Main-Sequence (ZAMS). This research concludes that, for intermediate-mass stars (M$>$1.3M$_\odot$), diagrams comparing the effective temperature ($T_{eff}$) against the small separation can provide an alternative to Christensen-Dalsgaard (C-D) diagrams. The impact of the metal abundance of intermediate mass stars (2.5-4.4M$_\odot$) has over their seismic properties is also evaluated.Comment: 4 pages, 5 figures, accepted for publication on A&

Transcriptome of the deep-sea black scabbardfish, Aphanopus carbo (Perciformes: Trichiuridae) : tissue-specific expression patterns and candidate genes associated to depth adaptation

Deep-sea fishes provide a unique opportunity to study the physiology and evolutionary adaptation to extreme environments. We carried out a high throughput sequencing analysis on a 454 GS-FLX titanium plate using unnormalized cDNA libraries from six tissues of A. carbo. Assemblage and annotations were performed by Newbler and InterPro/Pfam analyses, respectively. The assembly of 544,491 high quality reads provided 8,319 contigs, 55.6% of which retrieved blast hits against the NCBI nonredundant database or were annotated with ESTscan. Comparison of functional genes at both the protein sequences and protein stability levels, associated with adaptations to depth, revealed similarities between A. carbo and other bathypelagic fishes. A selection of putative genes was standardized to evaluate the correlation between number of contigs and their normalized expression, as determined by qPCR amplification. The screening of the libraries contributed to the identification of new EST simple-sequence repeats (SSRs) and to the design of primer pairs suitable for population genetic studies as well as for tagging and mapping of genes. The characterization of the deep-sea fish A. carbo first transcriptome is expected to provide abundant resources for genetic, evolutionary, and ecological studies of this species and the basis for further investigation of depth-related adaptation processes in fishes.Publisher PDFPeer reviewe

The MIPSGAL View of Supernova Remnants in the Galactic Plane

We report the detection of Galactic supernova remnants (SNRs) in the mid-infrared (at 24 and 70 μm), in the coordinate ranges 10° < l < 65° and 285° < l < 350°, |b| < 1°, using MIPS aboard the Spitzer Space Telescope. We search for infrared counterparts to SNRs in Green's catalog and identify 39 out of 121, i.e., a detection rate of about 32%. Such a relatively low detection fraction is mainly due to confusion with nearby foreground/background sources and diffuse emission. The SNRs in our sample show a linear trend in [F_8/F_(24)] versus [F_(70)/F_(24)]. We compare their infrared fluxes with their corresponding radio flux at 1.4 GHz and find that most remnants have a ratio of 70 μm to 1.4 GHz which is similar to those found in previous studies of SNRs (with the exception of a few that have ratios closer to those of H II regions). Furthermore, we retrieve a slope close to unity when correlating infrared (24 and 70 μm) with 1.4 GHz emission. Our survey is more successful in detecting remnants with bright X-ray emission, which we find is well correlated with the 24 μm morphology. Moreover, by comparing the power emitted in the X-ray, infrared, and radio, we conclude that the energy released in the infrared is comparable to the cooling in the X-ray range