193 research outputs found
Temporal disorder in up-down symmetric systems
The effect of temporal disorder on systems with up-down Z2 symmetry is
studied. In particular, we analyze two well-known families of phase
transitions: the Ising and the generalized voter universality classes, and
scrutinize the consequences of placing them under fluctuating global
conditions. We observe that variability of the control parameter induces in
both classes "Temporal Griffiths Phases" (TGP). These recently-uncovered phases
are analogous to standard Griffiths Phases appearing in systems with quenched
spatial disorder, but where the roles of space and time are exchanged. TGPs are
characterized by broad regions in parameter space in which (i) mean
first-passage times scale algebraically with system size, and (ii) the system
response (e.g. susceptibility) diverges. Our results confirm that TGPs are
quite robust and ubiquitous in the presence of temporal disorder. Possible
applications of our results to examples in ecology are discussed
Profile and competences of Spanish industrial engineers in the European Higher Education Area (EHEA)
The aim of this document is to develop a clear definition of the role of the industrial engineer. This is important in the Spanish context, where the engineer curricula are evolved in a different way than in other countries, due to the role developed by the Professional Associations of Engineers and Technical Engineers. To this end we identify here the professional profiles to be expected of those graduating from such courses, the sectors where they are most likely to be recruited, and the context within which industrial engineers are employed. We deal with meanings and proposals for Industrial Engineers within a European context, drawing information from the academic debate which has been launched in a number of scientific publications. The text summarizes our personal reflections, which are integrated within a proposal for action intended as an additional contribution to the critical debate as to the situation, rather than a final responsePeer Reviewe
Profile and competences of Spanish industrial engineers in the European Higher Education Area (EHEA)
Potential of the three-Terminal heterojunction bipolar transistor solar cell for space applications
Multi-Terminal multi-junction solar cells (MJSC) offer higher efficiency potential than series connected (two-Terminal) ones. In addition, for terrestrial applications, the efficiency of multi-Terminal solar cells is less sensitive to solar spectral variations than the two-Terminal series-connected one. In space, generally, cells are always illuminated with AM0 spectrum and no impact is expected from spectral variations. Still, in space, the multi-Terminal approach offers some advantages in comparison with the series-connected architecture approach derived from a higher end of life (EOL) efficiency. In this work we review the potential of multi-Terminal solar cells for achieving extended EOL efficiencies with emphasis in the potential of the three-Terminal heterojunction bipolar transistor solar cell, a novel multi-Terminal MJSC architecture with a simplified structure not requiring, for example, tunnel junctions
Resonant hyper-Raman scattering in spherical quantum dots
A theoretical model of resonant hyper-Raman scattering by an ensemble of
spherical semiconductor quantum dots has been developed. The electronic
intermediate states are described as Wannier-Mott excitons in the framework of
the envelope function approximation. The optical polar vibrational modes of the
nanocrystallites (vibrons) and their interaction with the electronic system are
analized with the help of a continuum model satisfying both the mechanical and
electrostatic matching conditions at the interface. An explicit expression for
the hyper-Raman scattering efficiency is derived, which is valid for incident
two-photon energy close to the exciton resonances. The dipole selection rules
for optical transitions and Fr\"ohlich-like exciton-lattice interaction are
derived: It is shown that only exciton states with total angular momentum
and vibrational modes with angular momentum contribute to the
hyper-Raman scattering process. The associated exciton energies, wavefunctions,
and vibron frequencies have been obtained for spherical CdSe zincblende-type
nanocrystals, and the corresponding hyper-Raman scattering spectrum and
resonance profile are calculated. Their dependence on the dot radius and the
influence of the size distribution on them are also discussed.Comment: 12 pages REVTeX (two columns), 2 tables, 8 figure
Inhomogeneous free-electron distribution in InN nanowires: Photoluminescence excitation experiments
Guidance on noncorticosteroid systemic immunomodulatory therapy in noninfectious uveitis: fundamentals of care for uveitis (focus) initiative
Topic: An international, expert-led consensus initiative to develop systematic, evidence-based recommendations for the treatment of noninfectious uveitis in the era of biologics.
Clinical Relevance: The availability of biologic agents for the treatment of human eye disease has altered practice patterns for the management of noninfectious uveitis. Current guidelines are insufficient to assure optimal use of noncorticosteroid systemic immunomodulatory agents.
Methods: An international expert steering committee comprising 9 uveitis specialists (including both ophthalmologists and rheumatologists) identified clinical questions and, together with 6 bibliographic fellows trained in uveitis, conducted a Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol systematic reviewof the literature (English language studies from January 1996 through June 2016; Medline [OVID], the Central Cochrane library, EMBASE,CINAHL,SCOPUS,BIOSIS, andWeb of Science). Publications included randomized controlled trials, prospective and retrospective studies with sufficient follow-up, case series with 15 cases or more, peer-reviewed articles, and hand-searched conference abstracts from key conferences. The proposed statements were circulated
among 130 international uveitis experts for review.Atotal of 44 globally representativegroupmembersmet in late 2016 to refine these guidelines using a modified Delphi technique and assigned Oxford levels of evidence.
Results: In total, 10 questions were addressed resulting in 21 evidence-based guidance statements covering the following topics: when to start noncorticosteroid immunomodulatory therapy, including both biologic and nonbiologic agents; what data to collect before treatment; when to modify or withdraw treatment; how to select agents based on individual efficacy and safety profiles; and evidence in specific uveitic conditions. Shared decision-making, communication among providers and safety monitoring also were addressed as part of the recommendations. Pharmacoeconomic considerations were not addressed.
Conclusions: Consensus guidelines were developed based on published literature, expert opinion, and practical experience to bridge the gap between clinical needs and medical evidence to support the treatment of patients with noninfectious uveitis with noncorticosteroid immunomodulatory agents
Food loss and waste metrics: a proposed nutritional cost footprint linking linear programming and life cycle assessment
Purpose: The main purpose of this article is to assess the nutritional and economic efficiency of food loss and waste (FLW) along the supply of 13 food categories included in the Spanish food basket by means of the definition of a new method which combines two indexes.
Methods: The nutrient-rich foods index and the economic food loss and waste (EFLW) index were combined by means of linear programming to obtain the nutritional cost footprint (NCF) indicator under a life cycle perspective. The functional unit used was the daily supply of food for a Spanish citizen in year 2015.
Results and discussion: Results showed that vegetables and cereals were the food categories most affected by the inefficiencies in the food supply chain under a nutritional perspective, being agricultural production and household consumption the main stages in which the nutritional content of food is lost or wasted. Moreover, according to the NCF index, vegetables represented 27% of total nutritional-economic wastage throughout the entire Spanish agri-food chain. They are followed by fruits, which add up to 19%. Hence, specific food waste management strategies should be established for these specific products and supply stages. Finally, the sensitivity analysis performed highlighted that results were mostly independent from the importance attributed to either nutritional or economic variables.
Conclusions: The methodology described in this study proposes an indicator quantifying the nutritional-economic cost of different food categories in the Spanish food basket. This NCF indicator makes it possible to define reduction strategies to promote the use of food waste fractions for waste-to-energy valorization approaches or the extraction of different types of pharmacological, chemical, or cosmetic compounds.The authors are grateful for the funding of the Spanish Ministry of Economy and Competitiveness through the Ceres-Procom: Food production and consumption strategies for climate change mitigation (CTM2016-76176-C2-1-R) (AEI/FEDER, UE)
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