447 research outputs found

    Charge Kondo effect toward a non-Fermi-liquid fixed point in the orbitally degenerate exchange model

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    We show that a Kondo-type model with an orbital degeneracy has a new non-Fermi-liquid fixed point. Near the fixed point the spin degrees of freedom are completely quenched, and the residual charge degrees of freedom lead to the multi-channel Kondo effect. Anomalous behavior appears in electric and thermal properties, but the magnetic susceptibility should show the local Fermi-liquid behavior. The non-Fermi-liquid fixed point becomes unstable against perturbations breaking the particle-hole symmetry. We derive these results using the third-order scaling for a spherically symmetric model with a fictitious spin. In contrast to the Coqblin-Schrieffer model, the present model respects different time-reversal properties of multipole operators.Comment: 4 pages, 2 eps figures, to appear in J. Phys. Soc. Jpn. 68 No.

    Crossover between Fermi Liquid and non-Fermi Liquid in Orbitally Degenerate Kondo Systems

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    Entanglement of spin and orbital Kondo effect is investigated on the basis of a Kondo-type exchange model with twofold orbital degeneracy. By using Wilson's numerical renormalization-group method, we examine dynamical and thermal properties respecting the difference in time-reversal property of multipole operators. In the presence of particle-hole symmetry, the model has a new non-Fermi-liquid fixed point with a fractional entropy. The spectral intensity of the quadrupole susceptibility diverges in the zero-frequency limit, while the dipole susceptibility shows a Fermi-liquid-like behavior. This is understood by mapping to the two-channel Kondo model, in which the dipole moment is mapped onto the operators with the scaling dimension Δm=1\Delta_m=1, while the quadrupole moment onto the operators with another scaling dimension Δe=1/2\Delta_e=1/2. Even for a fairly particle-hole asymmetric case with the Fermi-liquid ground state, the non-Fermi-liquid behavior has significant influences in electric and thermal properties.Comment: 7 pages, 9 figures, to appear in J. Phys Soc. Jpn. Vol. 68 No. 12, title changed and some corrections mad

    Transnational reflections on transnational research projects on men, boys and gender relations

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    This article reflects on the research project, ‘Engaging South African and Finnish youth towards new traditions of non-violence, equality and social well-being’, funded by the Finnish and South African national research councils, in the context of wider debates on research, projects and transnational processes. The project is located within a broader analysis of research projects and projectization (the reduction of research to separate projects), and the increasing tendencies for research to be framed within and as projects, with their own specific temporal and organizational characteristics. This approach is developed further in terms of different understandings of research across borders: international, comparative, multinational and transnational. Special attention is given to differences between research projects that are in the Europe and the EU, and projects that are between the global North and the global South. The theoretical, political and practical challenges of the North-South research project are discussed

    'A habitual disposition to the good': on reason, virtue and realism

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    Amidst the crisis of instrumental reason, a number of contemporary political philosophers including Jürgen Habermas have sought to rescue the project of a reasonable humanism from the twin threats of religious fundamentalism and secular naturalism. In his recent work, Habermas defends a post-metaphysical politics that aims to protect rationality against encroachment while also accommodating religious faith within the public sphere. This paper contends that Habermas’ post-metaphysical project fails to provide a robust alternative either to the double challenge of secular naturalism and religious fundamentalism or to the ruthless instrumentalism that underpins capitalism. By contrast with Habermas and also with the ‘new realism’ of contemporary political philosophers such as Raymond Geuss or Bernard Williams, realism in the tradition of Plato and Aristotle can defend reason against instrumental rationality and blind belief by integrating it with habit, feeling and even faith. Such metaphysical–political realism can help develop a politics of virtue that goes beyond communitarian thinking by emphasising plural modes of association (not merely ‘community’), substantive ties of sympathy and the importance of pursuing goodness and mutual flourishing

    Comparison of sequencing-based methods to profile DNA methylation and identification of monoallelic epigenetic modifications.

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    Analysis of DNA methylation patterns relies increasingly on sequencing-based profiling methods. The four most frequently used sequencing-based technologies are the bisulfite-based methods MethylC-seq and reduced representation bisulfite sequencing (RRBS), and the enrichment-based techniques methylated DNA immunoprecipitation sequencing (MeDIP-seq) and methylated DNA binding domain sequencing (MBD-seq). We applied all four methods to biological replicates of human embryonic stem cells to assess their genome-wide CpG coverage, resolution, cost, concordance and the influence of CpG density and genomic context. The methylation levels assessed by the two bisulfite methods were concordant (their difference did not exceed a given threshold) for 82% for CpGs and 99% of the non-CpG cytosines. Using binary methylation calls, the two enrichment methods were 99% concordant and regions assessed by all four methods were 97% concordant. We combined MeDIP-seq with methylation-sensitive restriction enzyme (MRE-seq) sequencing for comprehensive methylome coverage at lower cost. This, along with RNA-seq and ChIP-seq of the ES cells enabled us to detect regions with allele-specific epigenetic states, identifying most known imprinted regions and new loci with monoallelic epigenetic marks and monoallelic expression

    Governance and Interpretation: What are the Implications of Postfoundationalism?

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    Interpretive approaches to governance include poststructuralism, constructivist institutionalism, practical philosophy, and democratic pluralism. All of these interpretive approaches share a focus on meanings, sympathy for bottom-up studies, and an emphasis on contingency. All of them also confront theoretical issues that have arisen from the postfoundational turn within philosophy. They face questions about the nature of the meanings we study, the possibilities for recentring given an emphasis on diversity, and the normative and policy implications of their approach. Although poststructuralists have made the running in addressing these questions, their answers are ambiguous or even misleading. They often appear, in particular, mistakenly to renounce situated agency along with autonomy. This essay seeks to provide alternative answers to these theoretical questions and thereby to provide a more robust theoretical framework for interpretive approaches to governance

    deFuse: An Algorithm for Gene Fusion Discovery in Tumor RNA-Seq Data

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    Gene fusions created by somatic genomic rearrangements are known to play an important role in the onset and development of some cancers, such as lymphomas and sarcomas. RNA-Seq (whole transcriptome shotgun sequencing) is proving to be a useful tool for the discovery of novel gene fusions in cancer transcriptomes. However, algorithmic methods for the discovery of gene fusions using RNA-Seq data remain underdeveloped. We have developed deFuse, a novel computational method for fusion discovery in tumor RNA-Seq data. Unlike existing methods that use only unique best-hit alignments and consider only fusion boundaries at the ends of known exons, deFuse considers all alignments and all possible locations for fusion boundaries. As a result, deFuse is able to identify fusion sequences with demonstrably better sensitivity than previous approaches. To increase the specificity of our approach, we curated a list of 60 true positive and 61 true negative fusion sequences (as confirmed by RT-PCR), and have trained an adaboost classifier on 11 novel features of the sequence data. The resulting classifier has an estimated value of 0.91 for the area under the ROC curve. We have used deFuse to discover gene fusions in 40 ovarian tumor samples, one ovarian cancer cell line, and three sarcoma samples. We report herein the first gene fusions discovered in ovarian cancer. We conclude that gene fusions are not infrequent events in ovarian cancer and that these events have the potential to substantially alter the expression patterns of the genes involved; gene fusions should therefore be considered in efforts to comprehensively characterize the mutational profiles of ovarian cancer transcriptomes

    INSGFP/w human embryonic stem cells facilitate isolation of in vitro derived insulin-producing cells

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    AIMS/HYPOTHESIS: We aimed to generate human embryonic stem cell (hESC) reporter lines that would facilitate the characterisation of insulin-producing (INS⁺) cells derived in vitro. METHODS: Homologous recombination was used to insert sequences encoding green fluorescent protein (GFP) into the INS locus, to create reporter cell lines enabling the prospective isolation of viable INS⁺ cells. RESULTS: Differentiation of INS(GFP/w) hESCs using published protocols demonstrated that all GFP⁺ cells co-produced insulin, confirming the fidelity of the reporter gene. INS-GFP⁺ cells often co-produced glucagon and somatostatin, confirming conclusions from previous studies that early hESC-derived insulin-producing cells were polyhormonal. INS(GFP/w) hESCs were used to develop a 96-well format spin embryoid body (EB) differentiation protocol that used the recombinant protein-based, fully defined medium, APEL. Like INS-GFP⁺ cells generated with other methods, those derived using the spin EB protocol expressed a suite of pancreatic-related transcription factor genes including ISL1, PAX6 and NKX2.2. However, in contrast with previous methods, the spin EB protocol yielded INS-GFP⁺ cells that also co-expressed the beta cell transcription factor gene, NKX6.1, and comprised a substantial proportion of monohormonal INS⁺ cells. CONCLUSIONS/INTERPRETATION: INS(GFP/w) hESCs are a valuable tool for investigating the nature of early INS⁺ progenitors in beta cell ontogeny and will facilitate the development of novel protocols for generating INS⁺ cells from differentiating hESCs
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