3,100 research outputs found
A Multi-Criteria Non-Linear Optimization Model for the Control and Management of a Tropical Fishery
One of the principal problems when dealing with fishery resource management is to estimate strategies that satisfy biological, economic and social objectives simultaneously. As a contribution to solving this problem in the Yucatan Shelf Octopus (Octopus may a) fishery, a multi-criteria non-linear optimization procedure was applied to a dynamic bioeconomic model of the fishery. The procedure coped simultaneously with non linearities and system stochasticity. The min-max optimization, iteratively minimized the difference between the manager's objectives and model output values for the bioeconomic variables in a Pareto-optimal way. Results showed that it was possible to achieve explicit managerial objectives under different scenarios, such as those that simulate the normal 1988 fishing season, the impact of natural phenomena (hurricane Gilbert) and the reaction to such phenomena. Implications of the results are discussed.fishery management, management objectives, multi-criteria nonlinear optimization, tropical fishery, octopus, yucatan, optimal control, Environmental Economics and Policy, Resource /Energy Economics and Policy,
CWPO of bisphenol A with iron catalysts supported on microporous carbons from grape seeds activation
This accepted manuscript is available under a CC BY-NC-ND licence after the 24 months embargo periodThe catalytic wet peroxide oxidation (CWPO) of bisphenol A (BPA) with Fe catalysts supported on activated carbon from grape seeds (GS) has been studied. The GS were pyrolized (N2, 600 °C, 2 h) and subjected to activation upon partial gasification with air (400 °C, 2 h). Oxidized samples of the char and activated carbon were also obtained upon treatment with HNO3. The Fe catalysts were prepared by incipient wetness impregnation with ferric nitrate solution. They showed narrow microporosity, with surface area values â350â500 m2 gâ1 and total iron contents between 2.8 and 4.2% wt. The CWPO experiments were carried out at 50â80 °C. The best catalyst allowed complete conversion of BPA (100 mg Lâ1) and a 60% TOC reduction in 3 h reaction time at 80 °C and the theoretical stoichiometric amount of H2O2 (530 mg Lâ1). The ecotoxicity of the effluent was negligible and the biodegradability was highly improved. In a long-term experiment (100 h), the catalyst suffered a loss of activity upon the early stages on stream (â15 h), where about 20% of Fe was lost, followed by a highly stable behavior for the rest of the experimentThe authors wish to thank the Spanish MINECO and Comunidad de Madrid for the financial support through the projects CTM2013-43803-P and S2013/MAE-2716, respectively. I. F. Mena wishes to thank the MINECO and the ESF for a research gran
Aldol Reactions between L-Erythrulose Derivatives and Chiral α-Amino and α -Fluoro Aldehydes: Competition between FelkinâAnh and Cornforth Transition States
Both matched and mismatched diastereoselection have been observed in aldol reactions of a boron
enolate of a protected l-erythrulose derivative with several chiral α-fluoro and α-Amino aldehydes. Strict
adherence to the FelkinâAnh model for the respective transition structures does not account satisfactorily
for all the observed results, as previously observed in the case of α-oxygenatedaldehydes. In some cases,
only the Cornforth model provides a good explanation. The factors that influence this dichotomy are
discussed and a general mechanistic model is proposed for aldol reactions with a-heteroatom-substituted
aldehydes. Additional support for the model was obtained from density functional calculation
On the Transverse-Traceless Projection in Lattice Simulations of Gravitational Wave Production
It has recently been pointed out that the usual procedure employed in order
to obtain the transverse-traceless (TT) part of metric perturbations in lattice
simulations was inconsistent with the fact that those fields live in the
lattice and not in the continuum. It was claimed that this could lead to a
larger amplitude and a wrong shape for the gravitational wave (GW) spectra
obtained in numerical simulations of (p)reheating. In order to address this
issue, we have defined a consistent prescription in the lattice for extracting
the TT part of the metric perturbations. We demonstrate explicitly that the GW
spectra obtained with the old continuum-based TT projection only differ
marginally in amplitude and shape with respect to the new lattice-based ones.
We conclude that one can therefore trust the predictions appearing in the
literature on the spectra of GW produced during (p)reheating and similar
scenarios simulated on a lattice.Comment: 22 pages, 8 figures, Submitted to JCA
Parylene-AlOx Stacks for Improved 3D Encapsulation Solutions
The demand for ultra-tight encapsulation solutions with excellent barrier and high conformality properties has increased in recent years. To meet these challenges, thin-film barrier coatings have emerged as a promising solution. In this study, we investigate well-established silicon-based plasma-enhanced chemical vapor deposition (PECVD) and metal oxide atomic layer deposition (ALD) barrier coatings deposited at low temperatures (â€100 °C) regarding their abilities to address high-level 3D encapsulation applications. Various combinations of such layers are evaluated by measuring the water vapor transmission rate (WVTR) and considering the conformality properties. The impact and the benefits of the organic film integration, namely parylene VT4 grade, on the barrier performances is assessed. Among these combinations, parylene-AlOx stack emerges as one of the most effective solutions, obtaining a WVTR of 3.1 Ă 10^â4 g m^â2 day^â1 at 38°C and 90% relative humidity conditions
Double diastereoselection in anti aldol reactions mediated by dicyclohexylchloroborane between an L-erythrulose derivative and chiral aldehydes
Anti aldol reactions of an L-erythrulose derivative with several α-chiral aldehydes mediated by
dicyclohexylboron chloride are examined. Good yields and stereoselectivities are observed. The results
are best explained when the reactions are assumed to occur via boat-like transition states with
minimization of 1,3-allylic strain and avoidance of syn pentane interactions
Influence of STAT4 polymorphism in primary Sjögren's syndrome
Objective. To examine the influence of STAT4 rs7574865 gene polymorphism on patients with primary Sjögren's syndrome (SS). Methods. Two different cohorts were studied: 69 patients with primary SS and 296 controls from Colombia and 108 patients with primary SS and 227 controls from Germany. Samples were genotyped for the STAT4 rs7574865 single-nucleotide polymorphism with a predesigned TaqMan single-nucleotide polymorphism genotyping assay. We carried out a metaanalysis of our results combined with data published to date. Results. Although no significant differences were observed in the allele frequencies of STAT4 rs7574865 gene polymorphism between patients and controls in Colombians (p = 0.28, OR 1.24, 95% CI 0.82-1.87) and Germans (p = 0.08, OR 1.40, 95% CI 0.96-2.02), the metaanalysis disclosed a significant effect of the T allele on disease (p = 4.7 = 10-6, OR 1.40, 95% CI 1.21-1.62). Conclusion. These data reinforce the influence of STAT4 gene on primary SS and as a general autoimmune gene. The Journal of Rheumatology Copyright © 2010. All rights reserved
Sustainable Water-Energy Nexus towards Developing Countriesâ Water Sector Efficiency
Water management and energy recovery can improve a systemâs sustainability and efficiency in a cost-effective solution. This research assesses the renewable energy sources used in the water sector, as well as the related water sector performance indicators within Portuguese water management systems. A deep analysis of 432 water entities in Portugal, based on ERSAR data base, was conducted in order to identify factors to be improved regarding the system efficiency. On the other hand, the potential energy recovery developed in the REDAWN project was also used as a reference for the application of micro hydropower (MHP) solutions in the water sector. A water and energy nexus model was then developed to improve the systems efficiency and sustainability. A real case study in Africa, the Nampula water supply system, located in Mozambique, was selected as a promising potential for energy recovery. The application of a pump-as-turbine (PAT) allows the reduction in system costs and environmental impacts while increasing its efficiency. The proposed MHP has a capacity to generate ~23 MWh/year, providing significant savings. The developed economic analysis indicates the project is profitable, with an IRR ~40% depending on the energy selling price. This project can avoid the emission of more than 12 tCO2 to the atmosphere, and it can help to reduce the systemâs real losses by more than 10,000 m3/year. Consequently, it creates a total economic benefit of 7604 EUR/year
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