205 research outputs found
Statistical Properties and Economic Implications of Jump-Diffusion Processes with Shot-Noise Effects
This paper analyzes the Shot-Noise Jump-Diffusion model of Altmann, Schmidt and Stute (2008), which introduces a new situation where the effects of the arrival of rare, shocking information to the financial markets may fade away in the long run. We analyze several economic implications of the model, providing an analytical expression for the process distribution. We also prove that certain specifications of this model can provide negative serial persistence. Additionally, we find that the degree of serial autocorrelation is related to the arrival and magnitude of abnormal information. Finally, a GMM framework is proposed to estimate the model parameters.Filtered Poisson Process, Characteristic Function, Generalized Method of Moments
Multiwavelengt analysis of two peculiar High Mass X-Ray Binary systems : 4U 2206+54 and SAX J2103.5+4545 : New insights from Integral
Valuation and modeling of EQ-5D-5L health states using a hybrid approach
Background: The EQ-5D instrument is the most widely used preference-based health-related quality of life questionnaire in cost-effectiveness analysis of health care technologies. Recently, a version called EQ-5D-5L with 5 levels on each dimension was developed. This manuscript explores the performance of a hybrid approach for the modeling of EQ-5D-5L valuation data. Methods: Two elicitation techniques, the composite time trade-off, and discrete choice experiments, were applied to a sample of the Spanish population (n=1000) using a computer-based questionnaire. The sampling process consisted of 2 stages: stratified sampling of geographic area, followed by systematic sampling in each area. A hybrid regression model combining composite time trade-off and discrete choice data was used to estimate the potential value sets using main effects as starting point. The comparison between the models was performed using the criteria of logical consistency, goodness of fit, and parsimony. Results: Twenty-seven participants from the 1000 were removed following the exclusion criteria. The best-fitted model included 2 significant interaction terms but resulted in marginal improvements in model fit compared to the main effects model. We therefore selected the model results with main effects as a potential value set for this methodological study, based on the parsimony criteria. The results showed that the main effects hybrid model was consistent, with a range of utility values between 1 and -0.224. Conclusion: This paper shows the feasibility of using a hybrid approach to estimate a value set for EQ-5D-5L valuation data.</p
Fast oxidation of the neonicotinoid pesticides listed in the EU Decision 2018/840 from aqueous solutions
Neonicotinoid pesticides family is nowadays identified as the most important type of insecticides in the world. Their consequent widespread occurrence in the environment represents not only a well-known risk for bees but also a significant negative impact in aquatic ecosystems. In this work, the capability of catalytic wet peroxide oxidation (CWPO) (Fe3O4-R400/H2O2) as a low-cost and environmentally-friendly system for the treatment of the neonicotinoid pesticides listed in the EU Watch List (Decision 2018/840) (acetamiprid (ACT), clothianidin (CLT), imidacloprid (IMD), thiacloprid (THC) and thiamethoxam (THM)) has been investigated. Remarkably, complete elimination of the pollutants (1000 g L-1)and the aromatic by-products was reached in 20 min reaction time operating at 25 °C, 1 atm, and pH0 = 5,, with the stoichiometric H2O2 amount (~4 – 5 mg L-1) and 1 g L-1 catalyst load. The reactivity order of the insecticides decreased as follows: THC>IMD>THM>CLT>ACT, being the pseudo-first order rate constant values within the range of 0.26 – 0.61 min-1. Notably, high mineralization yields were obtained (>50%) being the final effluents non-toxic. As example, the oxidation pathway of ACT was proposed. Finally, the catalytic system was tested in real surface waterThis research has been founded by the CTM2016-76454-R project (Spanish MINECO) and
by the S2013/MAE-2716 project (CM). M. Munoz thanks the postdoctoral Ramón y Cajal contract (RYC-2016-20648) to the Spanish MINEC
Study of tyrosine and dopa enantiomers as tyrosinase substrates initiating L‐ and D‐melanogenesis pathways
Tyrosinase starts melanogenesis and determines its course, catalyzing the oxidation by molecular oxygen of tyrosine to dopa, and that of dopa to dopaquinone. Then, nonenzymatic coupling reactions lead to dopachrome, which evolves toward melanin. Recently, it has been reported that d‐tyrosine acts as tyrosinase inhibitor and depigmenting agent. The action of tyrosinase on the enantiomers of tyrosine (l‐tyrosine and d‐tyrosine) and dopa (l‐dopa and d‐dopa) was studied for the first time focusing on quantitative transient phase kinetics. Post‐steady‐state transient phase studies revealed that l‐dopachrome is formed more rapidly than d‐dopachrome. This is due to the lower values of Michaelis constants for l‐enantiomers than for d‐enantiomers, although the maximum rates are equal for both enantiomers. A deeper analysis of the inter‐steady‐state transient phase of monophenols demonstrated that the enantiomer d‐tyrosine causes a longer lag period and a lower steady‐state rate, than l‐tyrosine at the same concentration. Therefore, d‐melanogenesis from d‐tyrosine occurs more slowly than does l‐melanogenesis from l‐tyrosine, which suggests the apparent inhibition of melanin biosynthesis by d‐tyrosine. As conclusion, d‐tyrosine acts as a real substrate of tyrosinase, with low catalytic efficiency and, therefore, delays the formation of d‐melanin
La inclusión laboral de personas con diversidad funcional e imagen corporativa en empresas en Colombia: caso Securitas, Sodimac Homecenter y Alkosto
El trabajo muestra de que manera influye la inclusión laboral de personas con diversidad funcional en la imagen corporativa de las empresas, tomando como base el caso de 3 empresas en Colombia, Securitas, Home center y Alkosto. También se recolecto información valiosa de fundaciones que apoyan en estos procesos como lo son Arcángeles y Best Buddies. Todo se hizo partiendo de entrevistas a personal de talento humano de las empresas y fundaciones y encuestas a clientes y consumidores.1. Revisión de literatura ; 2. Metodología ; 3. Desarrollo de objetivos ; 4. Resuñltados de la investigación ; 5. Conclusiones ; 6. Recomendaciones ; 7. ReferenciasAdministrador de EmpresasPregrad
IUmote: A Framework for the Efficient Modelling, Evaluation, and Deployment of Algorithms and Hardware for Underwater Communications
We present an approach for the modelling and simulating of the modem section of underwater sensor networks. The proposal is based on a specially designed modem architecture and the use of simulation tools and models that represent each of the communication elements: the water medium, physical transducers, electronics, and coding/decoding software. The algorithms can be simulated in the modelling environment; this framework does not require recoding and allows the combination of real and modelled elements. In physical terms, the modem engine provides a decoupled pipelined design of the processing path for the algorithms which allows users to run complex algorithms without requiring a highly demanding specific hardware. The proposal includes a methodology that has allowed us to significantly reduce the effort required in the process, from algorithm development to the effective deployment of the system. As a case study, this paper shows its application and results in the evaluation of a multipath and Doppler-shift correction algorithms.The authors gratefully acknowledge financial support from the CICYT ANDREA: Automated Inspection and Remote Performance of Marine Fish Farms (CTM2011-29691-C02-01), RIDeWAM: Research on Improvement of the Dependability of WSN based Applications by developing a hybrid monitoring platform (TIN2011-28435-C03-01), Valencian Regional Government under Research Project GV/2014/012, and Universitat Politecnica de Valencia under Research Project UPV PAID-02-12. The translation of this paper was funded by the Universitat Politecnica de Valencia, Spain.Sánchez Matías, AM.; Perles Ivars, A.; Yuste Pérez, P.; Capella Hernández, JV.; Serrano Martín, JJ. (2015). IUmote: A Framework for the Efficient Modelling, Evaluation, and Deployment of Algorithms and Hardware for Underwater Communications. International Journal of Distributed Sensor Networks. 2015:1-14. https://doi.org/10.1155/2015/358315S114201
Spectroscopic observations of the δ Scorpii binary during its recent periastron passage
The bright star δ Sco has been considered a typical B0-type object for many years. Spectra of the star published prior to 1990 showed no evidence of emission, but only of short-term line profile variations attributed to nonradial pulsations. Speckle interferometric observations show that δ Sco is a binary system with a highlyeccentric orbit and a period of ~10.6 years. Weak emission in the Hα line was detected in its spectrum for the rst time during a periastron passage in 1990. Shortly before the next periastron passage in the summer of 2000, the binary entered a strong Hα emission and enhanced mass-loss phase. We monitored the spectroscopic development of the Be outburst from July 2000 through March 2001. In this paper we present results from our spectroscopy, refine elements of the binary orbit, and discuss possible mechanisms for the mass loss.Fabregat Llueca, Juan, [email protected] ;
Blay Serrano, Pedro Jose, [email protected]
Evaluation of the Damper Condition in Synchronous Motors through the Analysis of the Transient Stray Fluxes and Currents considering the Effect of the Remanent Magnetism
(c) 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.[EN] This paper proposes the qualitative and quantitative analysis of stray-flux and current data under starting to detect damper faults in cylindrical rotor synchronous machines. These machines are typically employed in high power applications and their possible outages may imply huge costs for the industries or plants where they operate. The damper cage is a critical part of these machines and a potential source of catastrophic failures. However, few research works have provided feasible alternatives to monitor the condition of such element. This work analyses the viability of analyzing the electromotive force signals induced by the stray-flux in external coil sensors as well as current signals under starting to diagnose damper faults. The results obtained with laboratory machines with different levels of damper damage show that the analyses of those signals can provide very useful information for determining how the damper degrades over time. Moreover, the paper studies the effect of the remanent magnetism over the viability of the approaches and provides solutions to overcome this problem. The conclusions are valuable for field engineers since, nowadays, there are few available solutions that allow monitoring the condition of such element without motor disassembly.This work was supported in part by the Spanish "Ministerio de Ciencia Innovacion y Universidades" and in part by the FEDER program in the framework of the "Proyectos de I+D de Generacion de Conocimiento del Programa Estatal de Generacion de Conocimiento y Fortalecimiento Cientifico y Tecnologico del Sistema de I+D+i, Subprograma Estatal de Generacion de Conocimiento" (ref: PGC2018-095747-B-I00).Castro-Coronado, H.; Antonino-Daviu, JA.; Quijano-Lopez, A.; Llovera Segovia, P.; Fuster Roig, VL.; Serrano Iribarnegaray, L.; Dunai, L. (2021). Evaluation of the Damper Condition in Synchronous Motors through the Analysis of the Transient Stray Fluxes and Currents considering the Effect of the Remanent Magnetism. IEEE Transactions on Industry Applications. 57(5):4665-4674. https://doi.org/10.1109/TIA.2021.30894574665467457
Quadrol-Pd(II) complexes: phosphine-free precatalysts for the room-temperature Suzuki-Miyaura synthesis of nucleoside analogues in aqueous media
Commercially available Quadrol, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine
(THPEN), has been used for the first time as N^N- donor neutral hydrophilic ligand in
the synthesis and characterization of new water soluble palladium (II) complexes
containing chloride, phthalimidate or saccharinate as co-ligands. [PdCl2(THPEN)] (1)
[Pd(phthal)2(THPEN)] (2), [Pd(sacc)2(THPEN)] (3) and the analogous complex with
the closely related N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine (THEEN)
[Pd(sacc)2(THEEN)] (4) were efficiently prepared in a one-pot reaction from
[PdCl2(CH3CN)2] or Pd(OAc)2. Structural characterization of 1 and 3 by single crystal
X-ray diffraction produced the first structures reported to date of palladium complexes
with Quadrol. The resultant palladium complexes are highly soluble in water and were
found to be effective as phosphine-free catalysts for the synthesis of functionalized
nucleoside analogues under room-temperature Suzuki-Miyaura cross-coupling
conditions between 5-iodo-2'-deoxyuridine (& 5-iodo-2'-deoxycytidine) with different
aryl boronic acids in neat water. This is the first report of the coupling process
performed on nucleosides in water at room temperature.This work has been partially supported by RTI2018-098233-B-C21 (MICINN) and
20790/PI/18 (Fundación SENECA CARM) grants. A.R.K would like to acknowledge
SERB for EMR grant (EMR/2016/005439). Professor Gregorio Sánchez, who recently
passed away, is gratefully acknowledged for his contribution to this work and his wise
and continuous advice and support
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