The fundamental properties of low-mass stars are not as well understood as those of their more massive counterparts. The best method for constraining these properties, especially masses and radii, is to study eclipsing binary systems, but only a small number of late-type ( M0) systems have been identified and well characterized to date. We present the discovery and characterization of six new M dwarf eclipsing binary systems. The 12 stars in these eclipsing systems have masses spanning 0.38-0.59 M and orbital periods of 0.6-1.7 days, with typical uncertainties of ∼0.3% in mass and ∼0.5%-2.0% in radius. Combined with six known systems with high-precision measurements, our results reveal an intriguing trend in the low-mass regime. For stars with M = 0.35-0.80 M , components in short-period binary systems (P 1 day; 12 stars) have radii which are inflated by up to 10% (μ = 4.8% ± 1.0%) with respect to evolutionary models for low-mass main-sequence stars, whereas components in longer-period systems (>1.5 days; 12 stars) tend to have smaller radii (μ = 1.7% ± 0.7%). This trend supports the hypothesis that short-period systems are inflated by the influence of the close companion, most likely because they are tidally locked into very high rotation speeds that enhance activity and inhibit convection. In summary, very close binary systems are not representative of typical M dwarfs, but our results for longer-period systems indicate that the evolutionary models are broadly valid in the M ∼ 0.35-0.80 M regime.

Abstract-This paper presents a generalized statistical texture analysis technique for characterizing and recognizing typical, diagnostically most important, vascular patterns relating to cervical lesions from colposcopic images. The contributions of the research include: 1) the introduction of a generalized texture analysis technique based on the combination of the conventional statistical and structural textural analysis approaches by using a statistical description of geometric primitives; 2) the introduction of a set of textural measures that capture the specific characteristics of cervical textures as perceived by human. Experimental study with real images demonstrated the feasibility and promising of the proposed approach in discriminating between cervical texture patterns indicative of different stages of cervical lesions.

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Photoelectric observations of eight optically identified radio sources and comparison stars in nearby fields are presented. Six of these objects have continuous spectra and may belong to the BL Lac class of variables. The reported observations indicate possible short-term, smallamplitude variations in some of the optical counterparts of the radio sources.