2,521 research outputs found

    A special class of solutions in F(R)F(R)-gravity

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    We consider a special class of vacuum F(R)F(R)-modified gravity models. The form of their Lagrangian is such that the field equations are trivially satisfied when the Ricci scalar is constant. There are many interesting F(R)F(R)-models for inflation and dark energy that fall in this class. However, little is known outside the domain of cosmology therefore we aim to explore the class of solutions that are static and spherically symmetric. After some general considerations, we investigate in more detail black hole solutions, traversable wormhole metrics and, finally, configurations that can match the anomalous rotation curves of galaxies.Comment: Minor typos corrected, references added. Version accepted for publication in the European Physical Journal

    The divine spirit of bees. A note on honey and the origins of yeast-driven fermentation

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    One of the earliest domesticated organisms is perhaps the eukaryote microorganism known as Saccharomyces cerevisiae, or more simply ‚Äúthe yeast‚ÄĚ. Its decisive role in triggering fermentation as a process useful for agricultural products preservation and transformation into consumable food, though known from the Palaeolithic in the ancient Near East, became decisive in the Neolithic Period. The earliest agriculturalists of the Fertile Crescent accidentally triggered fermentation with the addition of honey to fruits juices, as attested to in the archaeological record. The yeast, that lives inside the guts of bees and wasps, is responsible for this fermentation process. Honey contains both yeast and sugar that facilitates its growth generating fermentation. The creative capability of the bees let these insects to be credited of a divine skill

    Conceptual Design of a Decision Support System for the Economic Sustainability of Nonprofit Organizations

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    AbstractIn Italy, a continuous growth of nonprofit organizations has occurred in the last years. These organizations have been favoured by the concomitant reduction of direct public intervention (due to spending review) and the effect of the economic crisis on the business system. Despite their growth, nonprofit organizations present usually a critical lack in financial and economic management. In other words, their management does not consider all the factors related to economic balance, social success, reputation and promotion of their projects. The managerial role appears often to be overlooked compared to the actual needs and this results in a real limit for the growth and sustainability of these organizations. The present paper introduces a complete management review for the nonprofit using an Axiomatic Design based on the case study of one ‚ÄúMisericordia‚ÄĚ (onlus) located in Florence. The proposed application leads to the definition of the minimum set of assessment tools that have to be considered and used as a Decision Support System (DSS) to support the management in a nonprofit organization. The DSS is developed as an integrated system of tools which allows a systemic approach tailored to meet the specificity of this kind of organization

    GPGPU for track finding in High Energy Physics

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    The LHC experiments are designed to detect large amount of physics events produced with a very high rate. Considering the future upgrades, the data acquisition rate will become even higher and new computing paradigms must be adopted for fast data-processing: General Purpose Graphics Processing Units (GPGPU) is a novel approach based on massive parallel computing. The intense computation power provided by Graphics Processing Units (GPU) is expected to reduce the computation time and to speed-up the low-latency applications used for fast decision taking. In particular, this approach could be hence used for high-level triggering in very complex environments, like the typical inner tracking systems of the multi-purpose experiments at LHC, where a large number of charged particle tracks will be produced with the luminosity upgrade. In this article we discuss a track pattern recognition algorithm based on the Hough Transform, where a parallel approach is expected to reduce dramatically the execution time.Comment: 6 pages, 4 figures, proceedings prepared for GPU-HEP 2014 conference, submitted to DESY-PROC-201

    MARIO: A Versatile and User-Friendly Software for Building Input-Output Models

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    MARIO (Multi-Regional Analysis of Regions through Input-Output) is a Python-based framework for building input-output models. It automates the parsing of well-known databases (e.g. EXIOBASE, EORA, Eurostat) and of customized tables. With respect to similar tools, like pymrio, it broadens the scope of application to supply-use tables and handles both monetary and physical units. Employing an intuitive Excel-based API, it facilitates advanced table manipulations and allows for modelling additional supply chains through a hybrid LCA approach. It provides built-in functions for footprinting and scenario analyses as well as for visualizations of model outcomes. Results are exportable into various formats, possibly supplemented by a metadata file tracking the full history of applied changes. MARIO comes with extensive documentation and is available on Zenodo, GitHub, or installable via PyPI
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