11,595 research outputs found

    Accretion onto a Kiselev black hole

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    We consider accretion onto a Kiselev black hole. We obtain the fundamental equations for accretion without the back-reaction. We determine the general analytic expressions for the critical points and the mass accretion rate and find the physical conditions the critical points should fulfill. The case of polytropic gas are discussed in detail. It turns out that the quintessence parameter plays an important role in the accretion process.Comment: 7 page

    Optimal Estimation of a Classical Force with a Damped Oscillator in the non-Markovian Bath

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    We solve the optimal quantum limit of probing a classical force exactly by a damped oscillator initially prepared in the factorized squeezed state. The memory effects of the thermal bath on the oscillator evolution are investigated. We show that the optimal force sensitivity obtained by the quantum estimation theory approaches to zero for the non-Markovian bath, whereas approaches to a finite non-zero value for the Markovian bath as the energy of the damped oscillator goes to infinity.Comment: 5 pages, 4 figure

    A study on QOS routing for providing guaranteed services under multi-class traffic loads

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    Master'sMASTER OF ENGINEERIN

    Expression of miR-21 in Colorectal Cancer and Its Relationship with Clinicopathological Characteristics of Colorectal Cancer

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    Objective: To investigate the expression of miR-21 in colorectal cancer cells, and to analyze the relationship between the level of miR-21 and the clinicopathological characteristics of colorectal cancer patients. Methods: 210 patients with colorectal cancer treated in our hospital from January 2016 to June 2019 were selected. Cancer tissue specimens (study group) and adjacent normal tissue specimens (control group) were surgically collected, and the quantitative quantitative PCR was used to detect and compare the miR-21 expression of the two groups. Results: The expression of miR-21 in the study group was higher than that in the control group, and the difference was statistically significant (P <0.05). There were significant differences among patients with early and intermediate TNM, patients with low differentiation and patients with moderate to high differentiation, patients with lymph node metastasis and patients without lymph node metastasis, patients with high infiltration and patients with low infiltration, patients with high CEA levels, and patients with low CEA, and the difference was statistically significant (P <0.05). Conclusion: In colorectal cancer, miR-21 is highly expressed, which is closely related to stage and differentiation, and can be used to reflect the patient’s condition

    A Brief Summary of the Development of Farmer Cooperatives in China

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    Oral Presentatio

    Giving to Be Seen: the Influence of Facebook Charitable Advertisements on Conspicuous Donation Behavior

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    The arduous financial environments that nonprofit organizations face today motivate nonprofits to continuously search and leverage new communication platforms such as social media to approach a wider individual donor base. This thesis examines whether a Facebook charitable appeal promoting a donation via Facebook Gifts may attract Facebook users to give for conspicuousness (a public display of a donation behavior). Findings of this thesis revealed a gender difference in responses to the Facebook charitable appeal due to the gender difference in self-construals such that men were more likely to give via Facebook Gifts when the ad promoting the donation via Facebook Gifts signaled a lower level of popularity (with fewer Likes ) whereas women tended to give via Facebook Gifts when the ad signaled a higher level of popularity (with more Likes ). This thesis has theoretical contributions to existing literature on self-construals and prosocial behavior as well as significant practical implications for nonprofits to design compelling, effective charitable appeals to attract male and female social media users respectively
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