9,972 research outputs found
Double-lined M dwarf eclipsing binaries from Catalina Sky Survey and LAMOST
Eclipsing binaries provide a unique opportunity to determine fundamental
stellar properties. In the era of wide-field cameras and all-sky imaging
surveys, thousands of eclipsing binaries have been reported through light curve
classification, yet their basic properties remain unexplored due to the
extensive efforts needed to follow them up spectroscopically. In this paper we
investigate three M2-M3 type double-lined eclipsing binaries discovered by
cross-matching eclipsing binaries from the Catalina Sky Survey wtih
spectroscopically classified M dwarfs from the Large Sky Area Multi-Object
Fiber Spectroscopic Telescope survey data release one and two. Because these
three M dwarf binaries are faint, we further acquire radial velocity
measurements using GMOS on the Gemini North telescope with R~40000, enabling us
to determine the mass and radius of individual stellar components. By jointly
fitting the light and radial velocity curves of these systems, we derive the
mass and radius of the primary and secondary components of these three systems,
in the range between 0.28-0.42 M_sun and 0.29-0.67 R_sun, respectively. Future
observations with a high resolution spectrograph will help us pin down the
uncertainties in their stellar parameters, and render these systems benchmarks
to study m dwarfs, providing inputs to improving stellar models in the low mass
regime, or establishing an empirical mass-radius relation for M dwarf stars.Comment: RAA accepted. arXiv admin note: text overlap with arXiv:1701.0529
A Retinex-based Image Enhancement Scheme with Noise Aware Shadow-up Function
This paper proposes a novel image contrast enhancement method based on both a
noise aware shadow-up function and Retinex (retina and cortex) decomposition.
Under low light conditions, images taken by digital cameras have low contrast
in dark or bright regions. This is due to a limited dynamic range that imaging
sensors have. For this reason, various contrast enhancement methods have been
proposed. Our proposed method can enhance the contrast of images without not
only over-enhancement but also noise amplification. In the proposed method, an
image is decomposed into illumination layer and reflectance layer based on the
retinex theory, and lightness information of the illumination layer is
adjusted. A shadow-up function is used for preventing over-enhancement. The
proposed mapping function, designed by using a noise aware histogram, allows
not only to enhance contrast of dark region, but also to avoid amplifying
noise, even under strong noise environments.Comment: To appear in IWAIT-IFMIA 201
Cleavage of the Pt-S bond of thiolated terpyridine-platinum(II) complexes by copper(II) and zinc(II) ions in phosphate buffer
[[abstract]]Using the chelation of a triamine moiety and an S-bridged heterodinuclear unit, cleavage of the Pt–S bond in the thiolate–platinum complexes, [Pt(terpy)(BAT)]4+ and [Pt- (terpy)(AET)]+
is induced by adding transition metals such as Cu2+ or Zn2+ in phosphate buffer (pH 7–8) at room temp.[[booktype]]紙
Secretory Carcinoma: A Silent Mass Increasing in the Parotid Gland
BACKGROUND: Secretory carcinoma (SC) of the salivary gland, also known as mammary analog secretory carcinoma, is a rare tumor in the parotid gland. This kind of tumor is characterized by generally indolent clinical behavior and expression of a break in the ETV6 gene.
CASE REPORT: We present a unique case of secretory carcinoma and show its favorable prognoses.
CONCLUSION: Secretory carcinoma of the salivary gland is a low-grade carcinoma with a favorable prognosis. It has low regional lymph node and distant metastasis potential. Due to the possibility of misdiagnosis, immunohistochemical studies and FISH are suggested. The most effective treatment is complete surgical excision with negative surgical margins
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