52 research outputs found

    CCD photometric study of the W UMa-type binary II CMa in the field of Berkeley 33

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    The CCD photometric data of the EW-type binary, II CMa, which is a contact star in the field of the middle-aged open cluster Berkeley 33, are presented. The complete R light curve was obtained. In the present paper, using the five CCD epochs of light minimum (three of them are calculated from Mazur et al. (1993)'s data and two from our new data), the orbital period P was revised to 0.22919704 days. The complete R light curve was analyzed by using the 2003 version of W-D (Wilson-Devinney) program. It is found that this is a contact system with a mass ratio q=0.9q=0.9 and a contact factor f=4.1f=4.1%. The high mass ratio (q=0.9q=0.9) and the low contact factor (f=4.1f=4.1%) indicate that the system just evolved into the marginal contact stage

    A Critical Analysis Of The State-Of-The-Art On Automated Detection Of Deceptive Behavior In Social Media

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    Recently, a large body of research has been devoted to examine the user behavioral patterns and the business implications of social media. However, relatively little research has been conducted regarding users’ deceptive activities in social media; these deceptive activities may hinder the effective application of the data collected from social media to perform e-marketing and initiate business transformation in general. One of the main contributions of this paper is the critical analysis of the possible forms of deceptive behavior in social media and the state-of-the-art technologies for automated deception detection in social media. Based on the proposed taxonomy of major deception types, the assumptions, advantages, and disadvantages of the popular deception detection methods are analyzed. Our critical analysis shows that deceptive behavior may evolve over time, and so making it difficult for the existing methods to effectively detect social media spam. Accordingly, another main contribution of this paper is the design and development of a generic framework to combat dynamic deceptive activities in social media. The managerial implication of our research is that business managers or marketers will develop better insights about the possible deceptive behavior in social media before they tap into social media to collect and generate market intelligence. Moreover, they can apply the proposed adaptive deception detection framework to more effectively combat the ever increasing and evolving deceptive activities in social medi

    A Probabilistic Generative Model for Latent Business Networks Mining

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    The structural embeddedness theory posits that a company’s embeddedness in a business network impacts its competitive performance. This highlights the theoretical and practical values toward business network mining and analysis. Given the fact that latent business relationships may exist and business networks continuously evolve over time, a manual approach for the discovery and analysis of business network is ineffective. Though numerous research has been devoted to social network discovery and analysis, relatively little research is conducted on business network discovery. Guided by the design science research methodology, the main contribution of our research is the design and development of a novel probabilistic generative model for latent business relationship mining. The proposed method can effectively and efficiently discover evolving latent business networks over time. Our experimental results confirm that the proposed method outperforms the well-known vector space model based latent business relationship mining method by 28% in terms of AUC value

    Integrity and Junkiness Failure Handling for Embedding-based Retrieval: A Case Study in Social Network Search

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    Embedding based retrieval has seen its usage in a variety of search applications like e-commerce, social networking search etc. While the approach has demonstrated its efficacy in tasks like semantic matching and contextual search, it is plagued by the problem of uncontrollable relevance. In this paper, we conduct an analysis of embedding-based retrieval launched in early 2021 on our social network search engine, and define two main categories of failures introduced by it, integrity and junkiness. The former refers to issues such as hate speech and offensive content that can severely harm user experience, while the latter includes irrelevant results like fuzzy text matching or language mismatches. Efficient methods during model inference are further proposed to resolve the issue, including indexing treatments and targeted user cohort treatments, etc. Though being simple, we show the methods have good offline NDCG and online A/B tests metrics gain in practice. We analyze the reasons for the improvements, pointing out that our methods are only preliminary attempts to this important but challenging problem. We put forward potential future directions to explore

    Formulation and characterization of a novel, photoinitiated small intestinal sub-mucosal wound-healing hydrogel

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    Purpose: To design and characterize a novel 3-D photo-initiated small intestinal sub-mucosal (SIS) hydrogel for use as a scaffold.Methods: Two concentrations of hydrogel were used: 10 mg/mL SIS gel (designated as 1 % hydrogel) and 20 mg/mL SIS gel (designated as 2 % hydrogel). Cross-sections of the hydrogels were examined by scanning electron microscope. In vitro cell culture was carried out on the hydrogels, and cell count was obtained on each hydrogel at different time points. In addition, hematoxylin-eosin (H&E) staining was used to assess in vivo biodegradability of the gels, as well as tissue regeneration.Results: The 1 % hydrogel possessed a larger pore size (143 ± 22 Όm) than the 2 % hydrogel (113 ± 17 Όm) and showed significantly higher biodegradation rate (22.79 ± 2.47 % of gel left on day 5) than 2% hydrogel (35.37 ± 4.51 % of gel left on day 5) (p < 0.05). However, results from cell culture showed that the 2 % hydrogel had better biocompatibility than 1 % hydrogel. In vivo data revealed that the gels supported cell growth (cell count on days 3 and 5 were 48.33 ± 17.61 and 105.67 ± 21.36, respectively).Conclusion: These results suggest that SIS hydrogels have a high potential for application in tissue regeneration.Keywords: Extracellular matrix, Small intestinal sub-mucosa, Hydrogel, Wound healin

    Discovery of [11C]MK-6884: a positron emission tomography (PET) imaging agent for the study of M4 muscarinic receptor positive allosteric modulators (PAMs) in neurodegenerative diseases

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    The measurement of receptor occupancy (RO) using positron emission tomography (PET) has been instrumental in guiding discovery and development of CNS directed therapeutics. We and others have investigated muscarinic acetylcholine receptor 4 (M4) positive allosteric modulators (PAMs) for the treatment of symptoms associated with neuropsychiatric disorders. In this article, we describe the synthesis, in vitro, and in vivo characterization of a series of central pyridine-related M4 PAMs that can be conveniently radiolabeled with carbon-11 as PET tracers for the in vivo imaging of an allosteric binding site of the M4 receptor. We first demonstrated its feasibility by mapping the receptor distribution in mouse brain and confirming that a lead molecule 1 binds selectively to the receptor only in the presence of the orthosteric agonist carbachol. Through a competitive binding affinity assay and a number of physiochemical properties filters, several related compounds were identified as candidates for in vivo evaluation. These candidates were then radiolabeled with 11C and studied in vivo in rhesus monkeys. This research eventually led to the discovery of the clinical radiotracer candidate [11C]MK-6884

    Impossible Differential Distinguishers of Two Generalized Feistel Structures

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    Generalized Feistel structures are widely used in the design of block ciphers. In this paper, we focused on retrieving impossible differentials for two kinds of generalized Feistel structures: CAST256-like structure with Substitution-Permutation (SP) or Substitution-Permutation-Substitution (SPS) round functions (named CAST256SP and CAST256SPS, respectively) and MARS-like structure with SP/SPS round function (named MARSSP and MARSSPS, respectively). Known results show that for bijective round function, CAST256-like structures and MARS-like structures have (m2−1) and (2m−1) rounds impossible differentials, respectively. By our observation, there existed (m2+m) rounds impossible differentials in CAST256SP and (3m−3) rounds impossible differentials in MARSSPS (this result does not require the P layer to be invertible). When the diffusion layer satisfied some special conditions, CAST256SPS had (m2+m−1) rounds impossible differentials and MARSSPS had (3m−3) rounds impossible differentials

    Effects of Overexpression and Inhibited Expression of Thymosin, an Actin‐interacting Protein from Bombyx Mori, on BmNPV Proliferation and Replication

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    Previous study showed that exogenously applied recombinant thymosin from Bombyx mori (BmTHY) reduces B. mori nucleopolyhedrovirus (BmNPV) proliferation in silkworm. Which stands to reason that BmTHY in B. mori is crucial for the defense against BmNPV. However, little is known about the effect of endogenously overexpressed or repressed BmTHY on B. mori resistance to virus infection. To study this issue, we constructed an overexpression and inhibited expression systems of BmTHY in BmN cells. The viral titer and the analysis from the quantitative real‐time polymerase chain reaction (PCR) revealed that overexpression of BmTHY decreased the copies of BmNPV gene gp41, which goes over to inhibit the proliferation of BmNPV in BmN cells, while the inhibited expression of BmTHY significantly enhanced viral proliferation in infected BmN cells. These results indicated that endogenous BmTHY can inhibit BmNPV proliferation and replication in infected BmN cells. Furthermore, Co‐IP showed that BmTHY could bind to actin in BmN cells. Also, the overexpression or inhibited expression of BmTHY shifted the ratio of F/G‐actin in infected BmN cells. Lastly, the BmTHY, an actin‐interacting protein, might be one of the key host factors against BmNPV, which inhibits viral proliferation and replication in BmN cells
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