613 research outputs found

    An evaluation of Bradfordizing effects

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    The purpose of this paper is to apply and evaluate the bibliometric method Bradfordizing for information retrieval (IR) experiments. Bradfordizing is used for generating core document sets for subject-specific questions and to reorder result sets from distributed searches. The method will be applied and tested in a controlled scenario of scientific literature databases from social and political sciences, economics, psychology and medical science (SOLIS, SoLit, USB Köln Opac, CSA Sociological Abstracts, World Affairs Online, Psyndex and Medline) and 164 standardized topics. An evaluation of the method and its effects is carried out in two laboratory-based information retrieval experiments (CLEF and KoMoHe) using a controlled document corpus and human relevance assessments. The results show that Bradfordizing is a very robust method for re-ranking the main document types (journal articles and monographs) in today’s digital libraries (DL). The IR tests show that relevance distributions after re-ranking improve at a significant level if articles in the core are compared with articles in the succeeding zones. The items in the core are significantly more often assessed as relevant, than items in zone 2 (z2) or zone 3 (z3). The improvements between the zones are statistically significant based on the Wilcoxon signed-rank test and the paired T-Test

    Quantum algorithm and circuit design solving the Poisson equation

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    The Poisson equation occurs in many areas of science and engineering. Here we focus on its numerical solution for an equation in d dimensions. In particular we present a quantum algorithm and a scalable quantum circuit design which approximates the solution of the Poisson equation on a grid with error \varepsilon. We assume we are given a supersposition of function evaluations of the right hand side of the Poisson equation. The algorithm produces a quantum state encoding the solution. The number of quantum operations and the number of qubits used by the circuit is almost linear in d and polylog in \varepsilon^{-1}. We present quantum circuit modules together with performance guarantees which can be also used for other problems.Comment: 30 pages, 9 figures. This is the revised version for publication in New Journal of Physic

    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

    Deciphering the chemical dialogue between Bacillus and pathogenic fungi.

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    In nature, bacteria frequently form bacterial communities known as biofilms, where cells are embedded within an extracellular matrix (ECM) that provides protection against external aggressions or facilitates the efficient uptake and utilization of available resources. Interactions with other microbes can notably alter the community structure and, consequently, the nature of the relationship with the environment1. Previous studies of our laboratory have demonstrated the significance of biofilm formation in the antagonistic interaction between Bacillus and the phytopathogenic fungi Botrytis in the melon phyllosphere2. Our hypothesis is that the ECM plays a complementary role to the structural aspects of this antagonistic interaction. In this study, we dissect how the different components of Bacillus ECM mediate the adhesion of bacterial cells to Botrytis hyphae, which could enhance the efficient release of antifungal metabolites. We also describe how several purified components of the ECM and specific secondary metabolites of Bacillus participate in the chemical communication between Bacillus and Botrytis, thereby altering the physiology and metabolism of Botrytis. Our findings unveil that during this antagonistic interaction, Botrytis secrets different oxylipins, defence molecules capable of killing Bacillus. In response, Bacillus increases the production of several secondary metabolites, which appears to have antifungal effects. Our results underscore the urgency of further investigation of these interactions with the aim of identifying and describing adaptation processes that either lead to the exclusion or coexistence of two initially antagonistic microorganisms.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    Science Models as Value-Added Services for Scholarly Information Systems

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    The paper introduces scholarly Information Retrieval (IR) as a further dimension that should be considered in the science modeling debate. The IR use case is seen as a validation model of the adequacy of science models in representing and predicting structure and dynamics in science. Particular conceptualizations of scholarly activity and structures in science are used as value-added search services to improve retrieval quality: a co-word model depicting the cognitive structure of a field (used for query expansion), the Bradford law of information concentration, and a model of co-authorship networks (both used for re-ranking search results). An evaluation of the retrieval quality when science model driven services are used turned out that the models proposed actually provide beneficial effects to retrieval quality. From an IR perspective, the models studied are therefore verified as expressive conceptualizations of central phenomena in science. Thus, it could be shown that the IR perspective can significantly contribute to a better understanding of scholarly structures and activities.Comment: 26 pages, to appear in Scientometric

    Stable Modality-Specific Activity Flows As Reflected by the Neuroenergetic Approach to the fMRI Weighted Maps

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    This article uses the ideas of neuroenergetic and neural field theories to detect stimulation-driven energy flows in the brain during face and auditory word processing. In this analysis, energy flows are thought to create the stable gradients of the fMRI weighted summary images. The sources, from which activity spreads in the brain during face processing, were detected in the occipital cortex. The following direction of energy flows in the frontal cortex was described: the right inferior frontal = >the left inferior frontal = >the triangular part of the left inferior frontal cortex = >the left operculum. In the left operculum, a localized circuit was described. For auditory word processing, the sources of activity flows were detected bilaterally in the middle superior temporal regions, they were also detected in the left posterior superior temporal cortex. Thus, neuroenergetic assumptions may give a novel perspective for the analysis of neuroimaging data

    Solenodon genome reveals convergent evolution of venom in eulipotyphlan mammals

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    Venom systems are key adaptations that have evolved throughout the tree of life and typically facilitate predation or defense. Despite venoms being model systems for studying a variety of evolutionary and physiological processes, many taxonomic groups remain understudied, including venomous mammals. Within the order Eulipotyphla, multiple shrew species and solenodons have oral venom systems. Despite morphological variation of their delivery systems, it remains unclear whether venom represents the ancestral state in this group or is the result of multiple independent origins. We investigated the origin and evolution of venom in eulipotyphlans by characterizing the venom system of the endangered Hispaniolan solenodon (Solenodon paradoxus). We constructed a genome to underpin proteomic identifications of solenodon venom toxins, before undertaking evolutionary analyses of those constituents, and functional assessments of the secreted venom. Our findings show that solenodon venom consists of multiple paralogous kallikrein 1 (KLK1) serine proteases, which cause hypotensive effects in vivo, and seem likely to have evolved to facilitate vertebrate prey capture. Comparative analyses provide convincing evidence that the oral venom systems of solenodons and shrews have evolved convergently, with the 4 independent origins of venom in eulipotyphlans outnumbering all other venom origins in mammals. We find that KLK1s have been independently coopted into the venom of shrews and solenodons following their divergence during the late Cretaceous, suggesting that evolutionary constraints may be acting on these genes. Consequently, our findings represent a striking example of convergent molecular evolution and demonstrate that distinct structural backgrounds can yield equivalent functions

    Introduction revisiting the Argentine crisis a decade on: changes and continuities

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    This introductory chapter to the book "Argentina Since the 2001 Crisis Recovering the Past, Reclaiming the Future" analyses crisis and its associated responses and subsequent recovery in the context of Argentina’s multiple implosion of 2001-02 whilst also assessing its legacies for the country’s social, cultural, economic and political realms during the last decade. It recognises that "crisis" is a term that is much used in the post-Lehman Brothers world and that the subsequent responses and associated recoveries (or lack of) have been the subject of a cascade of academic, government, media, and think-tank investigation ever since. The chapter instead seeks to understand the nature of how crisis and its impacts should be investigated and interrogated, by rejecting false dichotomies of ‘old’ and ‘new’ and synthesising understanding to form an analysis that draws both elements of continuity and elements of change. Secondly, it argues that crisis manifests itself in a number of realms, and that heuristic devices employed to investigate them must subsequently also be drawn from across a range of disciplinary perspectives. Thirdly, it examines how the 2001-02 crisis in Argentina led to a series of responses that both rejected the neoliberal model yet also recovered elements of it. Finally it outlines the structure of the rest of the book, briefly summarising the chapters in turn

    Evaluation of SLC11A1 as an inflammatory bowel disease candidate gene

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    BACKGROUND: Significant evidence suggests that a promoter polymorphism withinthe gene SLC11A1 is involved in susceptibility to both autoimmune and infectious disorders. The aim of this study was to evaluate whether SLC11A1 has a role in the susceptibility to inflammatory bowel disease (IBD) by characterizing a promoter polymorphism within the gene and two short tandem repeat (STR) markers in genetic proximity to SLC11A1. METHODS: The studied population consisted of 484 Caucasians with IBD, 144 population controls, and 348 non-IBD-affected first-degree relatives of IBD patients. IBD subjects were re-categorized at the sub-disease phenotypic level to characterize possible SLC11A1 genotype-phenotype correlations. Polymorphic markers were amplified from germline DNA and typed using gel electrophoresis. Genotype-phenotype correlations were defined using case-control, haplotype, and family-based association studies. RESULTS: This study did not provide compelling evidence for SLC11A1 disease association; most significantly, there was no apparent evidence of SLC11A1 promoter allele association in the studied Crohn's disease population. CONCLUSION: Our results therefore refute previous studies that have shown SLC11A1 promoter polymorphisms are involved in susceptibility to this form of IBD
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