34,835 research outputs found

    Chemical Evolution in VeLLOs

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    A new type of object called "Very Low Luminosity Objects (VeLLOs)" has been discovered by the Spitzer Space Telescope. VeLLOs might be substellar objects forming by accretion. However, some VeLLOs are associated with strong outflows, indicating the previous existence of massive accretion. The thermal history, which significantly affects the chemistry, between substellar objects with a continuous low accretion rate and objects in a quiescent phase after massive accretion (outburst) must be greatly different. In this study, the chemical evolution has been calculated in an episodic accretion model to show that CO and N2H+ have a relation different from starless cores or Class 0/I objects. Furthermore, the CO2 ice feature at 15.2 micron will be a good tracer of the thermal process in VeLLOs.Comment: corrected e-mail addres

    Integrated genomic and transcriptomic analyses of radiation-induced malignancies

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    Cancer is a genetic disease caused by an unregulated expansion of a clone of cells (Sompayrac, 2004). The genetic abnormalities in cancer are the consequences of defective DNA replication, repair, maintenance, and modification, genetic background, and exposure to mutagens (Alexandrov et al., 2013). Ionizing radiation (IR), a mutagen exposed to cancer patients during clinical radiotherapy (RT), can cause DNA damage, genomic instability, and mutagenesis (Sherborne et al., 2015). While RT has been effective in treating cancer, it increases the risk of second malignant neoplasm (SMN), a severe delayed complication associated with mainly pediatric cancer survivors many decades after the treatment of their first cancer (Robison & Hudson, 2014). As the mortality of patients with childhood cancer has been decreasing, cases of radiation-induced cancers has been increasing (Robison & Hudson, 2014). The considerable contribution by RT to SMN risk illustrate the need to characterize the genetic mechanism directly responsible for radiation-induced malignancies. To better our understanding of the mutational landscape of SMNs, our specific aims are to identify potential driver mutations implicated in radiation-induced malignancies through genome and transcriptome analysis and to assess whether genetic background, specifically germline polymorphisms and mutations in tumor suppressor gene TP53, has an impact on the formation of secondary malignancies

    An endomorphism of the Khovanov invariant

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    We construct an endomorphism of the Khovanov invariant to prove H-thinness and pairing phenomena of the invariants for alternating links. As a consequence, it follows that the Khovanov invariant of an oriented nonsplit alternating link is determined by its Jones polynomial, signature, and the linking numbers of its components.Comment: To appear in Adv. Math.; Brief summary of Khovanov invariant (math.QA/9908171) and previous result of the author (math.GT/0201105) adde

    [Review of the book \u3ci\u3eSustainable Prosperity in the New Economy? Business Organization and High-Tech Employment in the United States\u3c/i\u3e]

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    [Excerpt] Best known as a business and economic historian, William (Bill) Lazonick may often escape the view of academics in human resource studies, organizational behavior, and labor relations. This is a mistake. Lazonick\u27s new book, Sustainable Prosperity in the New Economy?, is a must-read for scholars and students in these fields. He has chosen to study an important problem in the real world, has marshaled detailed empirical evidence to support his argument, and has used this evidence to critique conventional theory in economics and management
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