116 research outputs found

    The nuclear energy density functional formalism

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    The present document focuses on the theoretical foundations of the nuclear energy density functional (EDF) method. As such, it does not aim at reviewing the status of the field, at covering all possible ramifications of the approach or at presenting recent achievements and applications. The objective is to provide a modern account of the nuclear EDF formalism that is at variance with traditional presentations that rely, at one point or another, on a {\it Hamiltonian-based} picture. The latter is not general enough to encompass what the nuclear EDF method represents as of today. Specifically, the traditional Hamiltonian-based picture does not allow one to grasp the difficulties associated with the fact that currently available parametrizations of the energy kernel E[g,g]E[g',g] at play in the method do not derive from a genuine Hamilton operator, would the latter be effective. The method is formulated from the outset through the most general multi-reference, i.e. beyond mean-field, implementation such that the single-reference, i.e. "mean-field", derives as a particular case. As such, a key point of the presentation provided here is to demonstrate that the multi-reference EDF method can indeed be formulated in a {\it mathematically} meaningful fashion even if E[g,g]E[g',g] does {\it not} derive from a genuine Hamilton operator. In particular, the restoration of symmetries can be entirely formulated without making {\it any} reference to a projected state, i.e. within a genuine EDF framework. However, and as is illustrated in the present document, a mathematically meaningful formulation does not guarantee that the formalism is sound from a {\it physical} standpoint. The price at which the latter can be enforced as well in the future is eventually alluded to.Comment: 64 pages, 8 figures, submitted to Euroschool Lecture Notes in Physics Vol.IV, Christoph Scheidenberger and Marek Pfutzner editor

    Football friends: adolescent boys’ friendships inside an English professional football (soccer) academy.

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    This qualitative research draws on data from semi-structured, in-depth interviews to examine the friendships of twelve adolescent (14 and 15-year-old) boys within a professional football club Academy: a setting marked by competition for places. Findings highlight how boys fail to develop ‘deep’ friendships with other boys inside the club; their peer-relationships, even when described as ‘friendships,’ are devoid of trust and emotional intimacy. Instead, ‘being mates’ is experienced within parameters of instrumentalism and individualism leading to superficial and inauthentic friendships. There is some indication that boys developed closer friendships with boys outside of the Academy, suggesting that competition is implicated negatively in friendship-building and hinders the capabilities of these boys to develop close friendships with teammates. Concluding this paper, we acknowledge limitations of our data, discuss implications and challenges for football academies, and highlight directions for future research

    The non-adoption of supply chain management

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    This is an Accepted Manuscript of an article published by Taylor & Francis in Construction Management and Economics on 10th October 2013, available online: http://wwww.tandfonline.com/10.1080/01446193.2013.830186.Largely taken for granted within the UK construction sector has been a view that supply chain management theory is robust, relevant and reliable. As such it has formed a substantial aspect of previous and contemporary policy and government funded research. Despite this, the general view of its development and diffusion over the last 15 years within the construction industry has been problematic. Coincidentally, prevailing debates within the supply chain management academic community point to the lack of unified theory, models of diffusion and strong connections to organization theory. Using Straussian grounded theory, iterations between data and organization theory provided a fresh perspective on the development and diffusion of supply chain management in construction. This inductive research provided contextually rich explanations for development and diffusion that explicitly connected with and drew upon robust, relevant and reliable theories of institutions, innovation diffusion, triads, quasifirms and mechanisms of organizational governance. These explanations challenge the simplistic assumption that chains and networks of organizations are holistically managed and controlled by any single organization or institution in the construction industry. The debate therefore shifts away from proselytizing supply chain management towards research that explores the rigour, relevance and reliability of supply chain management assumptions in construction. The gap between industry practice and policy is exposed and the question is posed: to what extent policy and practice do, or should, constitute a recursive relationship.© 2013 Taylor & Francis

    Performance of novel VUV-sensitive Silicon Photo-Multipliers for nEXO

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    Liquid xenon time projection chambers are promising detectors to search for neutrinoless double beta decay (0νββ\nu \beta \beta), due to their response uniformity, monolithic sensitive volume, scalability to large target masses, and suitability for extremely low background operations. The nEXO collaboration has designed a tonne-scale time projection chamber that aims to search for 0νββ\nu \beta \beta of \ce{^{136}Xe} with projected half-life sensitivity of 1.35×10281.35\times 10^{28}~yr. To reach this sensitivity, the design goal for nEXO is \leq1\% energy resolution at the decay QQ-value (2458.07±0.312458.07\pm 0.31~keV). Reaching this resolution requires the efficient collection of both the ionization and scintillation produced in the detector. The nEXO design employs Silicon Photo-Multipliers (SiPMs) to detect the vacuum ultra-violet, 175 nm scintillation light of liquid xenon. This paper reports on the characterization of the newest vacuum ultra-violet sensitive Fondazione Bruno Kessler VUVHD3 SiPMs specifically designed for nEXO, as well as new measurements on new test samples of previously characterised Hamamatsu VUV4 Multi Pixel Photon Counters (MPPCs). Various SiPM and MPPC parameters, such as dark noise, gain, direct crosstalk, correlated avalanches and photon detection efficiency were measured as a function of the applied over voltage and wavelength at liquid xenon temperature (163~K). The results from this study are used to provide updated estimates of the achievable energy resolution at the decay QQ-value for the nEXO design

    Evidence for the Onset of Color Transparency in ρ0\rho^0 Electroproduction off Nuclei

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    We have measured the nuclear transparency of the incoherent diffractive A(e,eρ0)A(e,e'\rho^0) process in 12^{12}C and 56^{56}Fe targets relative to 2^2H using a 5 GeV electron beam. The nuclear transparency, the ratio of the produced ρ0\rho^0's on a nucleus relative to deuterium, which is sensitive to ρA\rho A interaction, was studied as function of the coherence length (lcl_c), a lifetime of the hadronic fluctuation of the virtual photon, and the four-momentum transfer squared (Q2Q^2). While the transparency for both 12^{12}C and 56^{56}Fe showed no lcl_c dependence, a significant Q2Q^2 dependence was measured, which is consistent with calculations that included the color transparency effects.Comment: 6 pages and 4 figure

    The immune landscape of cancer

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    We performed an extensive immunogenomic analysis of more than 10,000 tumors comprising 33 diverse cancer types by utilizing data compiled by TCGA. Across cancer types, we identified six immune subtypes—wound healing, IFN-γ dominant, inflammatory, lymphocyte depleted, immunologically quiet, and TGF-β dominant—characterized by differences in macrophage or lymphocyte signatures, Th1:Th2 cell ratio, extent of intratumoral heterogeneity, aneuploidy, extent of neoantigen load, overall cell proliferation, expression of immunomodulatory genes, and prognosis. Specific driver mutations correlated with lower (CTNNB1, NRAS, or IDH1) or higher (BRAF, TP53, or CASP8) leukocyte levels across all cancers. Multiple control modalities of the intracellular and extracellular networks (transcription, microRNAs, copy number, and epigenetic processes) were involved in tumor-immune cell interactions, both across and within immune subtypes. Our immunogenomics pipeline to characterize these heterogeneous tumors and the resulting data are intended to serve as a resource for future targeted studies to further advance the field

    The Immune Landscape of Cancer

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    We performed an extensive immunogenomic anal-ysis of more than 10,000 tumors comprising 33diverse cancer types by utilizing data compiled byTCGA. Across cancer types, we identified six im-mune subtypes\u2014wound healing, IFN-gdominant,inflammatory, lymphocyte depleted, immunologi-cally quiet, and TGF-bdominant\u2014characterized bydifferences in macrophage or lymphocyte signa-tures, Th1:Th2 cell ratio, extent of intratumoral het-erogeneity, aneuploidy, extent of neoantigen load,overall cell proliferation, expression of immunomod-ulatory genes, and prognosis. Specific drivermutations correlated with lower (CTNNB1,NRAS,orIDH1) or higher (BRAF,TP53,orCASP8) leukocytelevels across all cancers. Multiple control modalitiesof the intracellular and extracellular networks (tran-scription, microRNAs, copy number, and epigeneticprocesses) were involved in tumor-immune cell inter-actions, both across and within immune subtypes.Our immunogenomics pipeline to characterize theseheterogeneous tumors and the resulting data areintended to serve as a resource for future targetedstudies to further advance the field

    Perspective on Oncogenic Processes at the End of the Beginning of Cancer Genomics

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    The Cancer Genome Atlas (TCGA) has catalyzed systematic characterization of diverse genomic alterations underlying human cancers. At this historic junction marking the completion of genomic characterization of over 11,000 tumors from 33 cancer types, we present our current understanding of the molecular processes governing oncogenesis. We illustrate our insights into cancer through synthesis of the findings of the TCGA PanCancer Atlas project on three facets of oncogenesis: (1) somatic driver mutations, germline pathogenic variants, and their interactions in the tumor; (2) the influence of the tumor genome and epigenome on transcriptome and proteome; and (3) the relationship between tumor and the microenvironment, including implications for drugs targeting driver events and immunotherapies. These results will anchor future characterization of rare and common tumor types, primary and relapsed tumors, and cancers across ancestry groups and will guide the deployment of clinical genomic sequencing

    The Cancer Genome Atlas Comprehensive Molecular Characterization of Renal Cell Carcinoma

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    Renal cell carcinoma(RCC) is not a single disease, but several histologically defined cancers with different genetic drivers, clinical courses, and therapeutic responses. The current study evaluated 843 RCC from the three major histologic subtypes, including 488 clear cell RCC, 274 papillary RCC, and 81 chromophobe RCC. Comprehensive genomic and phenotypic analysis of the RCC subtypes reveals distinctive features of each subtype that provide the foundation for the development of subtype-specific therapeutic and management strategies for patients affected with these cancers. Somatic alteration of BAP1, PBRM1, and PTEN and altered metabolic pathways correlated with subtype-specific decreased survival, while CDKN2A alteration, increased DNA hypermethylation, and increases in the immune-related Th2 gene expression signature correlated with decreased survival within all major histologic subtypes. CIMP-RCC demonstrated an increased immune signature, and a uniform and distinct metabolic expression pattern identified a subset of metabolically divergent (MD) ChRCC that associated with extremely poor survival
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