1,184 research outputs found

    LexRank: Graph-based Lexical Centrality as Salience in Text Summarization

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    We introduce a stochastic graph-based method for computing relative importance of textual units for Natural Language Processing. We test the technique on the problem of Text Summarization (TS). Extractive TS relies on the concept of sentence salience to identify the most important sentences in a document or set of documents. Salience is typically defined in terms of the presence of particular important words or in terms of similarity to a centroid pseudo-sentence. We consider a new approach, LexRank, for computing sentence importance based on the concept of eigenvector centrality in a graph representation of sentences. In this model, a connectivity matrix based on intra-sentence cosine similarity is used as the adjacency matrix of the graph representation of sentences. Our system, based on LexRank ranked in first place in more than one task in the recent DUC 2004 evaluation. In this paper we present a detailed analysis of our approach and apply it to a larger data set including data from earlier DUC evaluations. We discuss several methods to compute centrality using the similarity graph. The results show that degree-based methods (including LexRank) outperform both centroid-based methods and other systems participating in DUC in most of the cases. Furthermore, the LexRank with threshold method outperforms the other degree-based techniques including continuous LexRank. We also show that our approach is quite insensitive to the noise in the data that may result from an imperfect topical clustering of documents

    Superconductivity in heavily compensated Mg-doped InN

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    We report superconductivity in Mg-doped InN grown by molecular beam epitaxy. Superconductivity phase transition temperature occurs Tc = 3.97 K as determined by magnetoresistance and Hall resistance measurements. The two-dimensional (2D) carrier density of the measured sample is n2D = 9×1014 cm−2 corresponding to a three-dimensional (3D) electron density of n3D = 1.8×1019 cm−3 which is within the range of values between Mott transition and the superconductivity to metal transition. We propose a plausible mechanism to explain the existence of the superconductivity in terms of a uniform distribution of superconducting InN nanoparticles or nanosized indium dots forming microscopic Josephson junctions in the heavily compensated insulating bulk InN matrix

    The role of learning on industrial simulation design and analysis

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    The capability of modeling real-world system operations has turned simulation into an indispensable problemsolving methodology for business system design and analysis. Today, simulation supports decisions ranging from sourcing to operations to finance, starting at the strategic level and proceeding towards tactical and operational levels of decision-making. In such a dynamic setting, the practice of simulation goes beyond being a static problem-solving exercise and requires integration with learning. This article discusses the role of learning in simulation design and analysis motivated by the needs of industrial problems and describes how selected tools of statistical learning can be utilized for this purpose

    A new multi-modal dataset for human affect analysis

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    In this paper we present a new multi-modal dataset of spontaneous three way human interactions. Participants were recorded in an unconstrained environment at various locations during a sequence of debates in a video conference, Skype style arrangement. An additional depth modality was introduced, which permitted the capture of 3D information in addition to the video and audio signals. The dataset consists of 16 participants and is subdivided into 6 unique sections. The dataset was manually annotated on a continuously scale across 5 different affective dimensions including arousal, valence, agreement, content and interest. The annotation was performed by three human annotators with the ensemble average calculated for use in the dataset. The corpus enables the analysis of human affect during conversations in a real life scenario. We first briefly reviewed the existing affect dataset and the methodologies related to affect dataset construction, then we detailed how our unique dataset was constructed

    Promoter methylation analysis of CDH1 and p14ARF genes in patients with urothelial bladder cancer

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    BACKGROUND/AIM: Urothelial bladder cancer arises from the accumulation of multiple epigenetic and genetic changes. We aimed to investigate the specificity and sensitivity of gene-specific promoter methylation of CDH1 and p14ARF genes in the early diagnosis of bladder cancer and compare those with other diagnostic tests in our population. PATIENTS AND METHODS: In the current study, 65 patients with urothelial bladder cancer and 35 controls without any history of cancer were recruited. Methylation profiles of CDH1 and p14ARF genes from tumor and urine samples were determined by methylation-specific polymerase chain reaction method. RESULTS: Methylation of CDH1 and p14ARF genes in tumor samples was 95.4% and 78.5%, respectively. The methylation frequencies were found to be 68.8% for CDH1 gene and 72.9% for p14ARF gene in urine samples. Sensitivities of CDH1, p14ARF and urine cytology were found to be 67.4%, 72.1% and 34.9%, respectively, while their specificities were 93.9%, 63.6% and 93.9%, respectively. CONCLUSION: Aberrant promoter methylation of CDH1 and p14ARF genes can be used to detect urothelial bladder cancer. In low-grade tumors, when compared with urine cytology, combined methylation analysis of CDH1 and p14ARF genes may not increase the sensitivity to identify malignant cells in urine samples

    Concise Review: Plasma and Nuclear Membranes Convey Mechanical Information to Regulate Mesenchymal Stem Cell Lineage

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    Numerous factors including chemical, hormonal, spatial, and physical cues determine stem cell fate. While the regulation of stem cell differentiation by soluble factors is well-characterized, the role of mechanical force in the determination of lineage fate is just beginning to be understood. Investigation of the role of force on cell function has largely focused on “outside-in” signaling, initiated at the plasma membrane. When interfaced with the extracellular matrix, the cell uses integral membrane proteins, such as those found in focal adhesion complexes to translate force into biochemical signals. Akin to these outside-in connections, the internal cytoskeleton is physically linked to the nucleus, via proteins that span the nuclear membrane. Although structurally and biochemically distinct, these two forms of mechanical coupling influence stem cell lineage fate and, when disrupted, often lead to disease. Here we provide an overview of how mechanical coupling occurs at the plasma and nuclear membranes. We also discuss the role of force on stem cell differentiation, with focus on the biochemical signals generated at the cell membrane and the nucleus, and how those signals influence various diseases. While the interaction of stem cells with their physical environment and how they respond to force is complex, an understanding of the mechanical regulation of these cells is critical in the design of novel therapeutics to combat diseases associated with aging, cancer, and osteoporosis

    The Highly Miniaturised Radiation Monitor

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    We present the design and preliminary calibration results of a novel highly miniaturised particle radiation monitor (HMRM) for spacecraft use. The HMRM device comprises a telescopic configuration of active pixel sensors enclosed in a titanium shield, with an estimated total mass of 52 g and volume of 15 cm3^3. The monitor is intended to provide real-time dosimetry and identification of energetic charged particles in fluxes of up to 108^8 cm2^{-2} s1^{-1} (omnidirectional). Achieving this capability with such a small instrument could open new prospects for radiation detection in space.Comment: 17 pages, 15 figure

    Association among sperm chromatin condensation, sperm DNA fragmentation and 8-OHdG in seminal plasma and semen parameters in infertile men with oligoasthenoteratozoospermia

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    The present study aimed to investigate the clinical role of standard sperm diagnosis parameters (sperm concentration, motility, morphology) as well as aniline blue staining of histones, 8-OHdG, TUNEL assay were performed on semen samples in infertile men with oligoasthenoteratozoospermia (OAT). Thirty-two infertile and ten proven fertile men were included in the study. Chromatin condensation sperm in infertile men was significantly lower compared to the fertile men (p < 0.0001). Age, sperm concentration, morphology and motility were significantly negatively correlated with chromatin condensation (p < 0.05). However, no significant correlations among the chromatin condensation, SDF and sperm DNA damage were detected in terms of 8- OHdG concentration
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