2,780 research outputs found
A special class of solutions in -gravity
We consider a special class of vacuum -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
-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
One of the earliest domesticated organisms is perhaps the eukaryote microorganism known as Saccharomyces cerevisiae, or more simply âthe yeastâ. 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
Assessing environmental and market implications of steel decarbonisation strategies: a hybrid input-output model for the European union
As a key material for manufacturing clean energy technologies, steel is crucial for energy transition, but its production causes 2.6 Gton of CO2 emissions at global level each year. In 2020 the European Union (EU) set a net-zero emissions target by 2050, fostering innovation in the steel industry to reduce its environmental impact. However, a scenario-oriented and technologically comprehensive analysis assessing prospected environmental and market implications of steel decarbonisation strategies remains a gap, which is addressed in this paper. The analysis adopts a hybrid input-output-based life-cycle assessment model built in the MARIO framework, extending the Exiobase database to represent the supply chains of the most promising low-carbon steelmaking technologies in the EU, such as hydrogen- or charcoal-injected blast furnaces and natural gas- and hydrogen-based direct reduction routes. The penetration of these technologies is explored by formulating scenarios resembling European climate targets. The results show a reduction in the carbon footprint of steel across all scenarios, ranging up to -26% in 2030 and to -60% in 2050. However, the extent of footprint reduction is highly dependent on the share of clean electricity in the European supply mix, highlighting the relevance of holistic decarbonisation strategies. Economic implications affect steel prices, which rise up to 25% in 2030 and 56% in 2050, opening discussions on the need for suitable policies such as CBAM to avoid protectionism and encourage international technological progress
Conceptual Design of a Decision Support System for the Economic Sustainability of Nonprofit Organizations
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 âMisericordiaâ (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
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
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