Theory of Stellar Oscillations

In recent years, astronomers have witnessed major progresses in the field of stellar physics. This was made possible thanks to the combination of a solid theoretical understanding of the phenomena of stellar pulsations and the availability of a tremendous amount of exquisite space-based asteroseismic data. In this context, this chapter reviews the basic theory of stellar pulsations, considering small, adiabatic perturbations to a static, spherically symmetric equilibrium. It starts with a brief discussion of the solar oscillation spectrum, followed by the setting of the theoretical problem, including the presentation of the equations of hydrodynamics, their perturbation, and a discussion of the functional form of the solutions. Emphasis is put on the physical properties of the different types of modes, in particular acoustic (p-) and gravity (g-) modes and their propagation cavities. The surface (f-) mode solutions are also discussed. While not attempting to be comprehensive, it is hoped that the summary presented in this chapter addresses the most important theoretical aspects that are required for a solid start in stellar pulsations research.Comment: Lecture presented at the IVth Azores International Advanced School in Space Sciences on "Asteroseismology and Exoplanets: Listening to the Stars and Searching for New Worlds" (arXiv:1709.00645), which took place in Horta, Azores Islands, Portugal in July 201

Prospects for asteroseismology

The observational basis for asteroseismology is being dramatically strengthened, through more than two years of data from the CoRoT satellite, the flood of data coming from the Kepler mission and, in the slightly longer term, from dedicated ground-based facilities. Our ability to utilize these data depends on further development of techniques for basic data analysis, as well as on an improved understanding of the relation between the observed frequencies and the underlying properties of the stars. Also, stellar modelling must be further developed, to match the increasing diagnostic potential of the data. Here we discuss some aspects of data interpretation and modelling, focussing on the important case of stars with solar-like oscillations.Comment: Proc. HELAS Workshop on 'Synergies between solar and stellar modelling', eds M. Marconi, D. Cardini & M. P. Di Mauro, Astrophys. Space Sci., in the press Revision: correcting abscissa labels on Figs 1 and

Common Missense Variant in the Glucokinase Regulatory Protein Gene Is Associated With Increased Plasma Triglyceride and C-Reactive Protein but Lower Fasting Glucose Concentrations

OBJECTIVE—Using the genome-wide association approach, we recently identified the glucokinase regulatory protein gene (GCKR, rs780094) region as a novel quantitative trait locus for plasma triglyceride concentration in Europeans. Here, we sought to study the association of GCKR variants with metabolic phenotypes, including measures of glucose homeostasis, to evaluate the GCKR locus in samples of non-European ancestry and to fine- map across the associated genomic interval

Synovial Sarcoma of the Tongue: Case Report and Review of the Literature

[No abstract available

A Clinical, Pathologic, And Molecular Study Of P53 And Murine Double Minute 2 In Penile Carcinogenesis And Its Relation To Prognosis

Penile carcinoma constitutes up to 16% of male malignancies in developing countries. Changes in the P53 and murine double minute 2 pathway are important events in various cancers. Associate alterations in murine double minute 2 and P53 expression were evaluated by molecular techniques, with the clinical data of 297 cases of penile carcinoma. Automated immunohistochemistry was performed for murine double minute 2 and P53 using the primary antibodies SPM14 and DO7, respectively. Fluorescent in situ hybridization was performed using the probes murine double minute 2 at 12q15 and TP53 at 17p13.1. Slides were digitalized, and bright-field and fluorescent images were analyzed. TP53 was sequenced in 16 cases. The expression of P53 was higher in poorly differentiated, infiltrative border, corpus spongiosum, corpora cavernosa, and invasive urethral carcinomas. Patients who died of disease also expressed higher levels of P53. P53-negative tumors were associated with higher overall survival. Murine double minute 2 showed no difference of expression in any group of tumors, no correlation with P53 expression. No alterations in genes or chromosomes were observed. Mutations in TP53 were observed in 4 of 16 cases: p.T170M, p.L252P, p.C176Y, and the novel c.803-810del8; these changes correlated with P53 expression by immunohistochemistry. Murine double minute 2 is not useful in the prognosis of penile carcinoma by immunohistochemistry. Additional studies on the transcriptional, posttranscriptional, and epigenetic aspects are necessary to understand the interactions between P53 and murine double minute 2 because we did not observe any numeric alterations by fluorescent in situ hybridization. Examining P53 is helpful in identifying patients with more aggressive tumors and may be crucial in selecting the most suitable surgical procedure. © 2012 Elsevier Inc. 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