1,720,960 research outputs found
Conformational Analysis of a Synthetic Antimicrobial Peptide in Water and Membrane-Mimicking Solvents: A Molecular Dynamics Simulation Study
Full text linkWe have investigated structural and dynamic properties of the synthetic peptide hlF1-11 (GRRRSVQWCA, i.e., the first 11 N-terminal amino acids of the human lactoferrin protein) in water, 250 mM NaCl solution, 50% (V/V) water–trifluoroethanol mixture, and in the membrane mimetic 4:4:1 methanol–chloroform–water mixture. For comparison, we have also performed analogous simulations for the biologically inactive control peptide featuring Ala substitutions in the 2, 3, 6 and 9 positions of the hlF1-11 sequence. Statistical analyses of the trajectories indicate that only in the membrane-mimicking medium hlF1-11 adopts preferentially a conformation suitable to interact effectively with the membrane. In this conformation the peptide cationic region is rather flexible and elongated, while the C-terminal hydrophobic moiety appears as a more rigid hairpin-shaped loop approximately perpendicular to the cationic region. No such conformation is statistically relevant for the control peptide
A Configuration-Independent Score-Based Benchmark for Distributed Databases
Full text linkThe business potential of big data is leading to a data-driven economy, where low-cost and low-latency data analysis represents a major competitive advantage. The research community has proposed many technological solutions for big data, such as NoSQL databases, which are difficult to evaluate and compare via standard IT procurement procedures. In addition, lack of competences in big data domains make procurement of big data solutions a tedious and uncertain process, which might impair the success of a business. In this paper, we present a score-based benchmark for distributed databases, which supports adopters in selecting a solution that fits their needs. The proposed benchmark is independent from the configurations of the specific database and deployment environment, requires low effort on the part of end users, is extensible and can be applied to both SQL and NoSQL databases, can be used to evaluate databases according to different properties (e.g., performance, consistency), and can be integrated with existing benchmarks to reduce the burden of their execution. We experimentally evaluate our methodology to validate its effectiveness
The open source virtual lab : a case study
No full textE-Learning is becoming a standard issue for Information Technologies degree courses. Video lessons, on-line exercises, and didactic forums, with interactions with tutors and teachers are already provided by current on-line degree courses. Within this scenario, there is a lack of virtual environments to allow students to make real experiences on network programming and configuration. In order to plug this gap, within the on-line degree course of ``Security of Informatics Systems and Networks'' provided by University of Milan, our group designed and realized the Virtual Lab, to offer to students a complete training environment accessible via web directly from normal web browser. This paper describes our fully open source solution and supplies a road map for other future works on virtual laboratories and online teaching
Learning computer networking on open paravirtual laboratories
No full textLearning practical information communication technology skills such as network configuration and security planning requires hands-on experience with a number of different devices which may be unavailable or too costly to provide, especially for institutions under tight budget constraints. This paper describes how a specific open software technology, paravirtualization, can be used to set up open source virtual networking labs (VNLs) easily and at virtually no cost. The paper highlights how paravirtual labs can be adopted jointly by partner organizations, e.g., when the institution hosting the virtual lab provides hands-on training and students' skill evaluation as a service to partner institutions overseas. A practical VNL implementation, the open virtual lab (OVL), is used to describe the added value that open source VNLs can give to e-Learning frameworks, achieving a level of students' performance comparable or better than the one obtained when students directly interact with physical networking equipment
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Scalability patterns for Platform-as-a-Service
No full textPlatform-as-a-Service is a cloud-based approach that provides enterprises with all the functionalities for developing, deploying, and administering services, without the burden of installing, configuring, and managing the underlying middleware, operating system, and hardware. In this context, scalability becomes a fundamental requirement, and appropriate solutions need to be studied and evaluated. In this paper, we present different scalability patterns for a Platform-as-a-Service infrastructure and a two-level approach to performance monitoring allowing automatic scalability management. We also provide a performance evaluation of the scalability patterns on a Service-Oriented Architecture (SOA) PaaS, which considers the impact on performance of SOA security standards
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