296 research outputs found
Density profiles and collective excitations of a trapped two component Fermi vapour
We discuss the ground state and the small-amplitude excitations of a
degenerate vapour of fermionic atoms placed in two hyperfine states inside a
spherical harmonic trap. An equations-of-motion approach is set up to discuss
the hydrodynamic dissipation processes from the interactions between the two
components of the fluid beyond mean-field theory and to emphasize analogies
with spin dynamics and spin diffusion in a homogeneous Fermi liquid. The
conditions for the establishment of a collisional regime via scattering against
cold-atom impurities are analyzed. The equilibrium density profiles are then
calculated for a two-component vapour of 40K atoms: they are little modified by
the interactions for presently relevant values of the system parameters, but
spatial separation of the two components will spontaneously arise as the number
of atoms in the trap is increased. The eigenmodes of collective oscillation in
both the total particle number density and the concentration density are
evaluated analytically in the special case of a symmetric two-component vapour
in the collisional regime. The dispersion relation of the surface modes for the
total particle density reduces in this case to that of a one-component Fermi
vapour, whereas the frequencies of all other modes are shifted by the
interactions.Comment: 14 pages, 4 figure
Spirulina in Clinical Practice: Evidence-Based Human Applications
Spirulina or Arthrospira is a blue-green alga that became famous after it was successfully used by NASA as a dietary supplement for astronauts on space missions. It has the ability to modulate immune functions and exhibits anti-inflammatory properties by inhibiting the release of histamine by mast cells. Multiple studies investigating the efficacy and the potential clinical applications of Spirulina in treating several diseases have been performed and a few randomized controlled trials and systematic reviews suggest that this alga may improve several symptoms and may even have an anticancer, antiviral and antiallergic effects. Current and potential clinical applications, issues of safety, indications, side-effects and levels of evidence are addressed in this review. Areas of ongoing and future research are also discussed
Embryo with XYY syndrome presenting with clubfoot: a case report
Talipes equinovarus (clubfoot) is a skeletal anomaly of the embryo’s legs, with a frequency of 1-3:1000 living born babies. It may occur as an independent anomaly, or as part of a syndrome with concomitant chromosomal abnormalities
Multi-disciplinary analysis of light shelves application within a student dormitory refurbishment
The achievement of sustainable cities and communities is closely linked to an accurate design of the buildings. In this context, the transparent elements of the building envelope have a crucial role since, on one hand, they are a bottleneck in regards to heat and mass transfers and sound propagation, while, on the other hand, they must allow daylight penetration. Thus, they are responsible for occupants' thermal and visual comfort and their health. Considering passive solutions for windows, the light shelves can improve natural light penetration, reducing the lights' electricity demand and controlling windows' related thermal aspects. The scientific literature is characterized by several studies that analyze this topic, which, however, focus only on the daylight field and sometimes the energy saving for lights. Moreover, they often refer to fixed sky type for the simulations. The aim of the present study is to analyze the application of the light shelves with a multi-disciplinary approach, by means of dynamic simulations, in the EnergyPlus engine, for a whole year. A new methodological approach is presented in order to investigate the technology under different fields of interest: daylight, lighting energy, cooling and heating needs, and thermo-hygrometric comfort. The case study chosen is an existing building, a student dormitory belonging to the University of Athens. It is subject to a deep energy renovation to conform to the "nearly Zero Energy Building" target, in the frame of a European research project called Pro-GET-onE (G.A No. 723747). By means of the calibrated numerical model of this HVAC-building system, ten different configurations of light shelves have been investigated. The best solution is given by the application of an internal horizontal light shelf placed at 50 cm from the top of the window with a depth of 90 or 60 cm. It has been found that despite the reduction in electricity demand for lighting, the variation in heating and cooling needs does not always lead to a benefit
Application of light shelves in a refurbished student dormitory: Energy, lightings and comfort aspects
The transparent elements of the building envelope have a crucial role not only in term of heat and mass transfers control, but also for natural light penetration, sound insulation, thermal and visual comfort of the occupants and their health. Among passive technologies, the light shelves could be architectural solutions for improving daylight penetration and for controlling thermal loads. The available research papers usually focus on one aspect. For this reason, the aim of the present study is to analyse the application of the light shelves with multidisciplinary approach and thus, taking into account: daylight, electricity for lighting, cooling and heating needs and thermo-hygrometric comfort. The case study is a real dormitory building placed in Athens and subject to a deep energy renovation toward the nearly zero energy building target. EnergyPlus, by means of DesignBuilder interface, has been used as dynamic simulation tool. Among ten different configurations, the optimal one turns out to be the internal horizontal light shelf placed at 50 cm from the top of the window with a depth of 90 cm or 60 cm. It has been found that in some cases the reduction of electricity for lighting cannot balance the variation in heating and cooling needs
Designing normative open virtual enterprises
This is an Accepted Manuscript of an article published by Taylor & Francis Group in
Enterprise Information Systems on 23/03/2016, available online: http://www.tandfonline.com/10.1080/17517575.2015.1036927.[EN] There is an increasing interest on developing virtual enterprises in order to deal with
the globalisation of the economy, the rapid growth of information technologies and the
increase of competitiveness. In this paper we deal with the development of normative
open virtual enterprises (NOVEs). They are systems with a global objective that are
composed of a set of heterogeneous entities and enterprises that exchange services
following a specific normative context. In order to analyse and design systems of this
kind the multi-agent paradigm seems suitable because it offers a specific solution for
supporting the social and contractual relationships between enterprises and for formalising
their business processes. This paper presents how the Regulated Open Multiagent
systems (ROMAS) methodology, an agent-oriented software methodology, can
be used to analyse and design NOVEs. ROMAS offers a complete development
process that allows identifying and formalising of the structure of NOVEs, their
normative context and the interactions among their members. The use of ROMAS is
exemplified by means of a case study that represents an automotive supply chain.This work was partially supported by the projects [PROMETEOII/2013/019], [TIN2012-36586-C03-01], [FP7-29493], [TIN2011-27652-C03-00] and [CSD2007-00022], and the CASES project within the 7th European Community Framework Programme [grant agreement number 294931].Garcia Marques, ME.; Giret Boggino, AS.; Botti Navarro, VJ. (2016). Designing normative open virtual enterprises. Enterprise Information Systems. 10(3):303-324. https://doi.org/10.1080/17517575.2015.1036927S303324103Cardoso, H. L., Urbano, J., Brandão, P., Rocha, A. P., & Oliveira, E. (2012). ANTE: Agreement Negotiation in Normative and Trust-Enabled Environments. Advances on Practical Applications of Agents and Multi-Agent Systems, 261-264. doi:10.1007/978-3-642-28786-2_33Chu, X. N., Tso, S. K., Zhang, W. J., & Li, Q. (2002). Partnership Synthesis for Virtual Enterprises. The International Journal of Advanced Manufacturing Technology, 19(5), 384-391. doi:10.1007/s001700200028Davidsson, P., & Jacobsson, A. (s. f.). Towards Norm-Governed Behavior in Virtual Enterprises. Studies in Computational Intelligence, 35-55. doi:10.1007/978-3-540-88071-4_3DeLoach, S. A., & Ojeda, J. C. G. (2010). O-MaSE: a customisable approach to designing and building complex, adaptive multi-agent systems. International Journal of Agent-Oriented Software Engineering, 4(3), 244. doi:10.1504/ijaose.2010.036984DI MARZO SERUGENDO, G., GLEIZES, M.-P., & KARAGEORGOS, A. (2005). Self-organization in multi-agent systems. The Knowledge Engineering Review, 20(2), 165-189. doi:10.1017/s0269888905000494Dignum, V. 2003. “A Model for Organizational Interaction: Based on Agents, Founded in Logic.” PhD diss., Utrecht University.Dignum, V., and F. Dignum. 2006.A Landscape of Agent Systems for the Real World. Technical Report 44-CS-2006-061. Utrecht: Institute of Information and Computing Sciences, Utrecht University.Dignum, V., Meyer, J.-J. C., Dignum, F., & Weigand, H. (2003). Formal Specification of Interaction in Agent Societies. Lecture Notes in Computer Science, 37-52. doi:10.1007/978-3-540-45133-4_4Garcia, E. 2013. “Engineering Regulated Open Multiagent Systems.” PhD diss., Universitat Politecnica de Valencia.Garcia, E., Giret, A., & Botti, V. (s. f.). Software Engineering for Service-Oriented MAS. Lecture Notes in Computer Science, 86-100. doi:10.1007/978-3-540-85834-8_9Garcia, E., Giret, A., & Botti, V. (2013). A Model-Driven CASE tool for developing and verifying regulated open MAS. Science of Computer Programming, 78(6), 695-704. doi:10.1016/j.scico.2011.10.009Garcia, E., Giret, A., & Botti, V. (2011). Evaluating software engineering techniques for developing complex systems with multiagent approaches. Information and Software Technology, 53(5), 494-506. doi:10.1016/j.infsof.2010.12.012Garcia, E., Giret, A., & Botti, V. (2011). Regulated Open Multi-Agent Systems Based on Contracts. Information Systems Development, 243-255. doi:10.1007/978-1-4419-9790-6_20Garcia, E., Giret, A., & Botti, V. (2014). ROMAS Methodology. Handbook on Agent-Oriented Design Processes, 331-369. doi:10.1007/978-3-642-39975-6_11Hollander, C. D., & Wu, A. S. (2011). The Current State of Normative Agent-Based Systems. Journal of Artificial Societies and Social Simulation, 14(2). doi:10.18564/jasss.1750HORLING, B., & LESSER, V. (2004). A survey of multi-agent organizational paradigms. The Knowledge Engineering Review, 19(4), 281-316. doi:10.1017/s0269888905000317Julian, V., Rebollo, M., Argente, E., Botti, V., Carrascosa, C., & Giret, A. (2009). Using THOMAS for Service Oriented Open MAS. Lecture Notes in Computer Science, 56-70. doi:10.1007/978-3-642-10739-9_5Luck, M., Barakat, L., Keppens, J., Mahmoud, S., Miles, S., Oren, N., … Taweel, A. (2011). Flexible Behaviour Regulation in Agent Based Systems. Lecture Notes in Computer Science, 99-113. doi:10.1007/978-3-642-22427-0_8Meneguzzi, F., Modgil, S., Oren, N., Miles, S., Luck, M., & Faci, N. (2012). Applying electronic contracting to the aerospace aftercare domain. Engineering Applications of Artificial Intelligence, 25(7), 1471-1487. doi:10.1016/j.engappai.2012.06.004Presley, A., Sarkis, J., Barnett, W., & Liles, D. (2001). International Journal of Flexible Manufacturing Systems, 13(2), 145-162. doi:10.1023/a:1011131417956Saeki, M., & Kaiya, H. (2008). Supporting the Elicitation of Requirements Compliant with Regulations. Active Flow and Combustion Control 2018, 228-242. doi:10.1007/978-3-540-69534-9_18Such, J. M., García-Fornes, A., Espinosa, A., & Bellver, J. (2013). Magentix2: A privacy-enhancing Agent Platform. Engineering Applications of Artificial Intelligence, 26(1), 96-109. doi:10.1016/j.engappai.2012.06.009Telang, P. R., & Singh, M. P. (2009). Enhancing Tropos with Commitments. Lecture Notes in Computer Science, 417-435. doi:10.1007/978-3-642-02463-4_22Wooldridgey, M., & Ciancarini, P. (2001). Agent-Oriented Software Engineering: The State of the Art. Lecture Notes in Computer Science, 1-28. doi:10.1007/3-540-44564-1_
New measurement of neutron capture resonances of 209Bi
The neutron capture cross section of Bi209 has been measured at the CERN n
TOF facility by employing the pulse-height-weighting technique. Improvements
over previous measurements are mainly because of an optimized detection system,
which led to a practically negligible neutron sensitivity. Additional
experimental sources of systematic error, such as the electronic threshold in
the detectors, summing of gamma-rays, internal electron conversion, and the
isomeric state in bismuth, have been taken into account. Gamma-ray absorption
effects inside the sample have been corrected by employing a nonpolynomial
weighting function. Because Bi209 is the last stable isotope in the reaction
path of the stellar s-process, the Maxwellian averaged capture cross section is
important for the recycling of the reaction flow by alpha-decays. In the
relevant stellar range of thermal energies between kT=5 and 8 keV our new
capture rate is about 16% higher than the presently accepted value used for
nucleosynthesis calculations. At this low temperature an important part of the
heavy Pb-Bi isotopes are supposed to be synthesized by the s-process in the He
shells of low mass, thermally pulsing asymptotic giant branch stars. With the
improved set of cross sections we obtain an s-process fraction of 19(3)% of the
solar bismuth abundance, resulting in an r-process residual of 81(3)%. The
present (n,gamma) cross-section measurement is also of relevance for the design
of accelerator driven systems based on a liquid metal Pb/Bi spallation target.Comment: 10 pages, 5figures, recently published in Phys. Rev.
Measurement of the (90,91,92,93,94,96)Zr(n,gamma) and (139)La(n,gamma) cross sections at n_TOF
Open AccessNeutron capture cross sections of Zr and La isotopes have important implications in the field of nuclear astrophysics as well as in the nuclear technology. In particular the Zr isotopes play a key role for the determination of the neutron density in the He burning zone of the Red Giant star, while the (139)La is important to monitor the s-process abundances from Ba up to Ph. Zr is also largely used as structural materials of traditional and advanced nuclear reactors. The nuclear resonance parameters and the cross section of (90,91,92,93,94,96)Zr and (139)La have been measured at the n_TOF facility at CERN. Based on these data the capture resonance strength and the Maxwellian-averaged cross section were calculated
Measurement of the neutron capture cross section of the s-only isotope 204Pb from 1 eV to 440 keV
The neutron capture cross section of 204Pb has been measured at the CERN
n_TOF installation with high resolution in the energy range from 1 eV to 440
keV. An R-matrix analysis of the resolved resonance region, between 1 eV and
100 keV, was carried out using the SAMMY code. In the interval between 100 keV
and 440 keV we report the average capture cross section. The background in the
entire neutron energy range could be reliably determined from the measurement
of a 208Pb sample. Other systematic effects in this measurement could be
investigated and precisely corrected by means of detailed Monte Carlo
simulations. We obtain a Maxwellian average capture cross section for 204Pb at
kT=30 keV of 79(3) mb, in agreement with previous experiments. However our
cross section at kT=5 keV is about 35% larger than the values reported so far.
The implications of the new cross section for the s-process abundance
contributions in the Pb/Bi region are discussed.Comment: 8 pages, 3 figures, article submitted to Phys. Rev.
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