6,811 research outputs found
Solar climate of Azores: results of monitoring at Faial and Terceira islands
The North Atlantic archipelago of Azores (Portugal) consists of nine islands, located about 1,500 km from mainland Europe. Currently the Azores has about 243,000 inhabitants, which depend heavily on imported fossil fuel for their energy supply. This is a concern for the regional Government and its Agency for Energy and Environment, ARENA, which naturally support energy efficiency and use of renewable energies. The Azores are rich in several renewable resources, and have even pioneered Portuguese exploitation of wind, wave, and high enthalpy geothermal energy for electricity generation. However, so far solar energy has not been a priority in the renewable energy panorama, probably because the Azores climate has been considered too cloudy. Nevertheless, this is true only in comparison with the Portuguese mainland, as the radiation levels are probably similar or even better than those of Northern Europe. In this context ARENA is developing efforts for increasing the use of solar systems. A collaboration, partly financed by an INTERREG III B Project of the European Community, has been established with INETI, the Portuguese Public Laboratory for the area of Energy, to improve the solar climatology of the Azores. This climatology is indeed quite incomplete. It consists mainly on daily measurements for two sites only at the S. Miguel and Terceira islands. Some sunshine records are available from Campbell-Stokes heliographs. Satellite data exists but their quality is uncertain due to the small size of the islands and the shallow view angle
Nonextensive thermostatistics and the H theorem
Using the Boltzmann's transport equation method, the kinetic foundations of Tsallis' nonextensive thermostatistics were investigated. The analysis follows from a nonextensive generalization of the 'molecular chaos hypothesis.' For q > 0, the q-transport equation satisfies an H theorem based on Tsallis entropy. It is also proved that the collisional equilibrium is given by Tsallis' q-nonextensive velocity distribution.Fil: Lima, J.A.. Universidade Federal do Rio Grande do Norte; BrasilFil: Silva, R.. Universidade Federal do Rio Grande do Norte; BrasilFil: Plastino, Ángel Ricardo. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Universitat de les Illes Balears; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin
Off diagonal charged scalar couplings with the Z boson: the Zee model as an example
Models with scalar doublets and charged scalar singlets have the interesting
property that they have couplings between one boson and two charged scalars
of different masses. This property is often ignored in phenomenological
analysis, as it is absent from models with only extra scalar doublets. We
explore this issue in detail, considering , , and the decay of a heavy charged scalar into a lighter one and a
boson. We propose that the latter be actively searched for at the LHC, using
the scalar sector of the Zee model as a prototype and proposing benchmark
points which obey all current experimental data and could be within reach of
the LHC.Comment: 40 pages, 28 Figures in PD
Scalable processing and autocovariance computation of big functional data
This is the peer reviewed version of the following article: Brisaboa NR, Cao R, Paramá JR, Silva-Coira F. Scalable processing and autocovariance computation of big functional data. Softw Pract Exper. 2018; 48: 123–140 which has been published in final form at https://doi.org/10.1002/spe.2524 . This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.[Abstract]: This paper presents 2 main contributions. The first is a compact representation of huge sets of functional data or trajectories of continuous-time stochastic processes, which allows keeping the data always compressed even during the processing in main memory. It is oriented to facilitate the efficient computation of the sample autocovariance function without a previous decompression of the data set, by using only partial local decoding. The second contribution is a new memory-efficient algorithm to compute the sample autocovariance function. The combination of the compact representation and the new memory-efficient algorithm obtained in our experiments the following benefits. The compressed data occupy in the disk 75% of the space needed by the original data. The computation of the autocovariance function used up to 13 times less main memory, and run 65% faster than the classical method implemented, for example, in the R package.This work was supported by the Ministerio de Economía y Competitividad (PGE and FEDER) under grants [TIN2016-78011-C4-1-R; MTM2014-52876-R; TIN2013-46238-C4-3-R], Centro para el desarrollo Tecnológico e Industrial MINECO [IDI-20141259; ITC-20151247; ITC-20151305; ITC-20161074]; Xunta de Galicia (cofounded with FEDER) under Grupos de Referencia Competitiva grant ED431C-2016-015; Xunta de Galicia-Consellería de Cultura, Educación e Ordenación Universitaria (cofounded with FEDER) under Redes grants R2014/041, ED341D R2016/045; Xunta de Galicia-Consellería de Cultura, Educación e Ordenación Universitaria (cofounded with FEDER) under Centro Singular de Investigación de Galicia grant ED431G/01.Xunta de Galicia; D431C-2016-015Xunta de Galicia; R2014/041Xunta de Galicia; ED341D R2016/045Xunta de Galicia; ED431G/0
Causal Reasoning for Algorithmic Fairness
In this work, we argue for the importance of causal reasoning in creating
fair algorithms for decision making. We give a review of existing approaches to
fairness, describe work in causality necessary for the understanding of causal
approaches, argue why causality is necessary for any approach that wishes to be
fair, and give a detailed analysis of the many recent approaches to
causality-based fairness
Overcoming inertia : drivers of the outsourcing process
Almost all managers have directly or indirectly been involved in the practice of outsourcing in recent years. But as they know, outsourcing is not straightforward. Outsourcing inertia, when companies are slow to adapt to changing circumstances that accommodate higher outsourcing levels, may undermine a firm’s performance. This article investigates the presence of outsourcing inertia and the factors that help managers overcome it. Using statistical evidence, we show that positive performance effects related to outsourcing can accumulate when circumstances change. This is then followed by rapid increases in outsourcing levels (i.e. outsourcing processes). We investigate what gives rise to these outsourcing processes through follow-up interviews with sourcing executives, which suggest five drivers behind outsourcing processes: managerial initiative (using outside experience); hierarchy (foreign headquarters); imitation (of competitors and of similar firms); outsider advice (from external institutions); knowledge sources (using external information). These five drivers all offer scope for managerial action. We tie them to academic literatures and suggest ways of investigating their presence and impact on the outsourcing process. Overall, we conclude that while economizing factors play a key role in explaining how much firms outsource, it is socializing factors that tend to drive outsourcing processes
KINEMATIC COMPARISON BETWEEN ATHLETES FROM THE INTERNATIONAL AND THE WORLD TAEKWONDO FEDERATIONS IN THE ROUNDHOUSE KICK
Taekwondo (TKD) is a combat sport organized by two main federations: International TKD (ITF) and the World TKD (WTF). The present study analyzed the kinematic differences in roundhouse kick performed by ITF and WTF athletes. Seventeen athletes participated in the study (8 ITF; 9 WTF). DVideo system was used to reconstruct the 3D coordinates of sixteen markers. Pelvis and hips angles and angular velocities were used to compare the groups. The results highlight two kick strategies to hit the target. WTF athletes performed the kick with increased pelvis left rotation while ITF used increased pelvis anteversion, hip flexion and abduction on supporting leg. These differences should be considered for adaptation of rules and training
Mathematical model of brain tumour with glia-neuron interactions and chemotherapy treatment
Acknowledgements This study was possible by partial financial support from the following Brazilian government agencies: Fundação Araucária, EPSRC-EP/I032606/1 and CNPq, CAPES and Science Without Borders Program Process nos. 17656125, 99999.010583/2013-00 and 245377/2012-3.Peer reviewedPreprin
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