Experimental Phase-Space Tomography of Semiconductor Laser Dynamics

© 2015 American Physical Society. We perform phase-space tomography of semiconductor laser dynamics by simultaneous experimental determination of optical intensity, frequency, and population inversion with high temporal resolution. We apply this technique to a laser with delayed feedback, serving as prominent example for high-dimensional chaotic dynamics and as model system for fundamental investigations of complex systems. Our approach allows us to explore so far unidentified trajectories in phase space and identify the underlying physical mechanism.This work was supported by Comunitat Autònoma de les Illes Balears via program Grups Competitius, FEDER and MINECO via project TRIPHOP (TEC2012-36335).Peer Reviewe

Empowered communities or "cheap labour"? : Engaging volunteers in the rationalised management of invasive alien species in Great Britain

The authors would like to thank all the organisations and volunteers who participated in this study, as well as Anja Byg, Kerry Waylen, Michelle Pinard, Norman Dandy and three anonymous reviewers for their valuable comments on earlier versions of this paper. We acknowledge funding by the Natural Environment Research Council and the Rivers and Fisheries Trusts of Scotland (NERC-CASE PhD scholarship 12994499) and support by the Rural & Environment Science and Analytical Services Division of the Scottish Government.Peer reviewedPostprin

Elements to be Considered to Study a Possible Cannabis Legalization in Chile

Desde 1961 que los gobiernos del mundo han optado por una política de control de drogas basada en la prohibición de su consumo, en 1973 se prohíbe el consumo del cannabis en Chile. Desde entonces, el consumo de dicha sustancia no ha hecho más que aumentar dejando a nuestro país como uno de los mayores consumidores de América Latina. El propósito de este trabajo es identificar y proponer temas de discusión a los investigadores de políticas públicas para analizar una posible legalización del cannabis. Se realiza una revisión sistemática de las publicaciones sobre la marihuana en Chile a partir de lo cual se logra identificar tan solo nueve trabajos relacionados con las políticas públicas al respecto. En consecuencia, se proponen al menos tres líneas de investigación: la incorporación de la legalización del cannabis en la agenda pública, el diseño y la evaluación de políticas y programas relacionados y el tipo de tributación que le correspondería, lo anterior en el entendido estos temas deben tener un enfoque multisectorial y comprehensivo.Since 1961 world governments have opted for a drugs policy based on consumption prohibition, in 1973 the consumption of cannabis was prohibited in Chile. Since then, the consumption of that substance has done nothing but increase, situating our country among one of greatest consumers in Latin America. The aim of this work is to identify and propose discussion topics to public policy scholars for analyzing a possible legalization of cannabis. A systematic review of publications on cannabis in Chile was made, detecting only nine works dealt with related public policies. Consequently, at least three lines of research were proposed: inclusion of cannabis legalization on the public agenda, policy and related programs evaluation and design, the type of taxation that would be more appropriate, all of it understanding that these issues should be addressed with a comprehensive and multisectoral approach

A VARIAÇÃO LEXICAL E FONOLÓGICA NA LIBRAS NA EXPRESSÃO DO CONCEITO ‘ELEVADOR’

This work aims (1) to investigate the lexical and phonetic-phonological variation through the reanalysis of 21 productions referring to the concept ‘elevator’, originally collected by Xavier and F. Barbosa (2017) from 12 deaf signers from the state of São Paul, and (2) to compare our results with those of the aforementioned authors. To achieve this, unlike the previous study, the reanalyzed productions were first grouped by a deaf signer who uses Libras as her first language into different lexical variants based on their iconicity (motivation) and not on their formal similarity. Subsequently, the variant and stable phonetic-phonological aspects in the productions of each lexical variant were analyzed by their comparison. As a result, we observed a differece in the number of lexical variants in both studies, but similarities in the results related to the variable and stable phonetic-phological features.O presente trabalho objetiva (1) investigar a variação lexical e fonético-fonológica na libras através da reanálise de 21 produções referentes ao conceito ‘elevador’, originalmente coletadas por Xavier e F. Barbosa (2017) de 12 sinalizantes surdos do estado de São Paulo, e (2) comparar nossos resultados com os dos referidos autores. Para isso, diferentemente do estudo anterior, as produções reanalisadas foram primeiramente agrupadas por uma sinalizante surda usuária de libras como primeira língua em diferentes variantes lexicais com base em sua iconicidade (motivação) e não na sua semelhança formal. Posteriormente, foram analisados os aspectos fonético-fonológicos variantes e estáveis nas produções de cada variante lexical por meio de sua comparação. Como resultado, observou-se diferença em relação no número de variantes lexicais nos dois estudos, mas semelhanças nos resultados relacionados à variação e à estabilidade fonético-fonológicas

Dynamical properties induced by state-dependent delays in photonic systems

© 2015 Macmillan Publishers Limited. All rights reserved. In many dynamical systems and complex networks time delays appear naturally in feedback loops or coupling connections of individual elements. Moreover, in a whole class of systems, these delay times can depend on the state of the system. Nevertheless, so far the understanding of the impact of such state-dependent delays remains poor with a particular lack of systematic experimental studies. Here we fill this gap by introducing a conceptually simple photonic system that exhibits dynamics of self-organised switching between two loops with two different delay times, depending on the state of the system. On the basis of experiments and modelling on semiconductor lasers with frequency-selective feedback mirrors, we characterize the switching between the states defined by the individual delays. Our approach opens new perspectives for the study of this class of dynamical systems and enables applications in which the self-organized switching can be exploited.This work was supported by MINECO (Spain) under Project TEC2012-36335 (TRIPHOP) and FIS2012-30634 (INTENSE@COSYP), Govern de les Illes Balears via the program Grups Competitius and Formació de Personal Investigador and the European Commission via FEDER and European Social Fund.Peer Reviewe

Autocorrelation properties of chaotic delay dynamical systems: A study on semiconductor lasers

We present a detailed experimental characterization of the autocorrelation properties of a delayed feedback semiconductor laser for different dynamical regimes. We show that in many cases the autocorrelation function of laser intensity dynamics can be approximated by the analytically derived autocorrelation function obtained from a linear stochastic model with delay. We extract a set of dynamic parameters from the fit with the analytic solutions and discuss the limits of validity of our approximation. The linear model captures multiple fundamental properties of delay systems, such as the shift and asymmetric broadening of the different delay echoes. Thus, our analysis provides significant additional insight into the relevant physical and dynamical properties of delayed feedback lasers

Pd@UiO-66-Type MOFs Prepared by Chemical Vapor Infiltration as Shape-Selective Hydrogenation Catalysts

[EN] Host-guest inclusion properties of UiO-66 and UiO-67 metal-organic frameworks have been studied using ferrocene (FeCp2) as probe molecule. According to variable-temperature solid-state H-1 and C-13 CP-MAS-NMR, two different environments exist for adsorbed FeCp2 inside UiO-66 and UiO-67, which have been assigned to octahedral and tetrahedral cavities. At room temperature, a rapid exchange between these two adsorption sites occurs in UiO-67, while at -80 degrees C the intracrystalline traffic of FeCp2 through the triangular windows is largely hindered. In UiO-66, FeCp2 diffusion is already impeded at room temperature, in agreement with the smaller pore windows. Palladium nanoparticles (Pd NPs) encapsulated inside UiO-66 and UiO-67 have been prepared by chemical vapor infiltration of (allyl)Pd(Cp) followed by UV light irradiation. Infiltration must be carried out at low temperature (-10 degrees C) to avoid uncontrolled decomposition of the organometallic precursor and formation of Pd NPs at the external surface of the MOF. The resulting Pd-MOFs are shape selective catalysts, as shown for the hydrogenation of carbonyl compounds with different steric hindrance.Financial support from the Consolider-Ingenio 2010 (project MULTICAT), the Severo Ochoa program, and the Spanish Ministry of Science and Innovation (project MAT2011-29020-C02-01) is gratefully acknowledged. C. R. is grateful for a graduate student fellowship awarded by the Cluster of Excellence RESOLV (EXC 1069) funded by the German Deutsche Forschungsgemeinschaft (DFG). This project has further received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skolodowska-Curie grant agreement, number 641887.Luz Mínguez, I.; Roesler, C.; Epp, K.; Llabrés I Xamena, FX.; Fischer, RA. (2015). Pd@UiO-66-Type MOFs Prepared by Chemical Vapor Infiltration as Shape-Selective Hydrogenation Catalysts. European Journal of Inorganic Chemistry. 23:3904-3912. https://doi.org/10.1002/ejic.201500299S3904391223Corma, A., García, H., & Llabrés i Xamena, F. X. (2010). Engineering Metal Organic Frameworks for Heterogeneous Catalysis. Chemical Reviews, 110(8), 4606-4655. doi:10.1021/cr9003924Farrusseng, D., Aguado, S., & Pinel, C. (2009). Metal-Organic Frameworks: Opportunities for Catalysis. Angewandte Chemie International Edition, 48(41), 7502-7513. doi:10.1002/anie.200806063Gascon, J., Corma, A., Kapteijn, F., & Llabrés i Xamena, F. X. (2013). Metal Organic Framework Catalysis: Quo vadis? ACS Catalysis, 4(2), 361-378. doi:10.1021/cs400959kLlabres i Xamena, F., & Gascon, J. (Eds.). (2013). Metal Organic Frameworks as Heterogeneous Catalysts. Catalysis Series. doi:10.1039/9781849737586Li, B., Wang, H., & Chen, B. (2014). Microporous Metal-Organic Frameworks for Gas Separation. Chemistry - An Asian Journal, 9(6), 1474-1498. doi:10.1002/asia.201400031Li, J.-R., Kuppler, R. J., & Zhou, H.-C. (2009). Selective gas adsorption and separation in metal–organic frameworks. Chemical Society Reviews, 38(5), 1477. doi:10.1039/b802426jKreno, L. E., Leong, K., Farha, O. K., Allendorf, M., Van Duyne, R. P., & Hupp, J. T. (2011). Metal–Organic Framework Materials as Chemical Sensors. Chemical Reviews, 112(2), 1105-1125. doi:10.1021/cr200324tEsken, D., Turner, S., Lebedev, O. I., Van Tendeloo, G., & Fischer, R. A. (2010). Au@ZIFs: Stabilization and Encapsulation of Cavity-Size Matching Gold Clusters inside Functionalized Zeolite Imidazolate Frameworks, ZIFs. Chemistry of Materials, 22(23), 6393-6401. doi:10.1021/cm102529cHermes, S., Schröter, M.-K., Schmid, R., Khodeir, L., Muhler, M., Tissler, A., … Fischer, R. A. (2005). Metal@MOF: Loading of Highly Porous Coordination Polymers Host Lattices by Metal Organic Chemical Vapor Deposition. Angewandte Chemie International Edition, 44(38), 6237-6241. doi:10.1002/anie.200462515Meilikhov, M., Yusenko, K., Esken, D., Turner, S., Van Tendeloo, G., & Fischer, R. A. (2010). Metals@MOFs - Loading MOFs with Metal Nanoparticles for Hybrid Functions. European Journal of Inorganic Chemistry, 2010(24), 3701-3714. doi:10.1002/ejic.201000473Schröder, F., Esken, D., Cokoja, M., van den Berg, M. W. E., Lebedev, O. I., Van Tendeloo, G., … Fischer, R. A. (2008). Ruthenium Nanoparticles inside Porous [Zn4O(bdc)3] by Hydrogenolysis of Adsorbed [Ru(cod)(cot)]: A Solid-State Reference System for Surfactant-Stabilized Ruthenium Colloids. Journal of the American Chemical Society, 130(19), 6119-6130. doi:10.1021/ja078231uRösler, C., Esken, D., Wiktor, C., Kobayashi, H., Yamamoto, T., Matsumura, S., … Fischer, R. A. (2014). Encapsulation of Bimetallic Nanoparticles into a Metal-Organic Framework: Preparation and Microstructure Characterization of Pd/Au@ZIF-8. European Journal of Inorganic Chemistry, 2014(32), 5514-5521. doi:10.1002/ejic.201402409Müller, M., Hermes, S., Kähler, K., van den Berg, M. W. E., Muhler, M., & Fischer, R. A. (2008). Loading of MOF-5 with Cu and ZnO Nanoparticles by Gas-Phase Infiltration with Organometallic Precursors: Properties of Cu/ZnO@MOF-5 as Catalyst for Methanol Synthesis. Chemistry of Materials, 20(14), 4576-4587. doi:10.1021/cm703339hMüller, M., Zhang, X., Wang, Y., & Fischer, R. A. (2009). Nanometer-sized titania hosted inside MOF-5. Chem. Commun., (1), 119-121. doi:10.1039/b814241fRösler, C., & Fischer, R. A. (2015). Metal–organic frameworks as hosts for nanoparticles. CrystEngComm, 17(2), 199-217. doi:10.1039/c4ce01251hHermannsdörfer, J., Friedrich, M., Miyajima, N., Albuquerque, R. Q., Kümmel, S., & Kempe, R. (2012). Ni/Pd@MIL-101: Synergistic Catalysis with Cavity-Conform Ni/Pd Nanoparticles. Angewandte Chemie International Edition, 51(46), 11473-11477. doi:10.1002/anie.201205078Cirujano, F. G., Llabrés i Xamena, F. X., & Corma, A. (2012). MOFs as multifunctional catalysts: One-pot synthesis of menthol from citronellal over a bifunctional MIL-101 catalyst. Dalton Transactions, 41(14), 4249. doi:10.1039/c2dt12480gCirujano, F. G., Leyva-Pérez, A., Corma, A., & Llabrés i Xamena, F. X. (2013). MOFs as Multifunctional Catalysts: Synthesis of Secondary Arylamines, Quinolines, Pyrroles, and Arylpyrrolidines over Bifunctional MIL-101. ChemCatChem, 5(2), 538-549. doi:10.1002/cctc.201200878Guo, Z., Xiao, C., Maligal-Ganesh, R. V., Zhou, L., Goh, T. W., Li, X., … Huang, W. (2014). Pt Nanoclusters Confined within Metal–Organic Framework Cavities for Chemoselective Cinnamaldehyde Hydrogenation. ACS Catalysis, 4(5), 1340-1348. doi:10.1021/cs400982nLi, X., Guo, Z., Xiao, C., Goh, T. W., Tesfagaber, D., & Huang, W. (2014). Tandem Catalysis by Palladium Nanoclusters Encapsulated in Metal–Organic Frameworks. ACS Catalysis, 4(10), 3490-3497. doi:10.1021/cs5006635Zhang, W., Lu, G., Cui, C., Liu, Y., Li, S., Yan, W., … Huo, F. (2014). A Family of Metal-Organic Frameworks Exhibiting Size-Selective Catalysis with Encapsulated Noble-Metal Nanoparticles. Advanced Materials, 26(24), 4056-4060. doi:10.1002/adma.201400620Chen, L., Chen, H., Luque, R., & Li, Y. (2014). Metal−organic framework encapsulated Pd nanoparticles: towards advanced heterogeneous catalysts. Chem. Sci., 5(10), 3708-3714. doi:10.1039/c4sc01847hRamsahye, N. A., Gao, J., Jobic, H., Llewellyn, P. L., Yang, Q., Wiersum, A. D., … Maurin, G. (2014). Adsorption and Diffusion of Light Hydrocarbons in UiO-66(Zr): A Combination of Experimental and Modeling Tools. The Journal of Physical Chemistry C, 118(47), 27470-27482. doi:10.1021/jp509672cCatal. Today 2014Cirujano, F. G., Corma, A., & Llabrés i Xamena, F. X. (2015). Conversion of levulinic acid into chemicals: Synthesis of biomass derived levulinate esters over Zr-containing MOFs. Chemical Engineering Science, 124, 52-60. doi:10.1016/j.ces.2014.09.047Vermoortele, F., Ameloot, R., Vimont, A., Serre, C., & De Vos, D. (2011). An amino-modified Zr-terephthalate metal–organic framework as an acid–base catalyst for cross-aldol condensation. Chem. Commun., 47(5), 1521-1523. doi:10.1039/c0cc03038dVermoortele, F., Bueken, B., Le Bars, G., Van de Voorde, B., Vandichel, M., Houthoofd, K., … De Vos, D. E. (2013). Synthesis Modulation as a Tool To Increase the Catalytic Activity of Metal–Organic Frameworks: The Unique Case of UiO-66(Zr). Journal of the American Chemical Society, 135(31), 11465-11468. doi:10.1021/ja405078uVermoortele, F., Vandichel, M., Van de Voorde, B., Ameloot, R., Waroquier, M., Van Speybroeck, V., & De Vos, D. E. (2012). Electronic Effects of Linker Substitution on Lewis Acid Catalysis with Metal-Organic Frameworks. Angewandte Chemie International Edition, 51(20), 4887-4890. doi:10.1002/anie.201108565McClellan, W. R., Hoehn, H. H., Cripps, H. N., Muetterties, E. L., & Howk, B. W. (1961). π-Allyl Derivatives of Transition Metals. Journal of the American Chemical Society, 83(7), 1601-1607. doi:10.1021/ja01468a013Schaate, A., Roy, P., Godt, A., Lippke, J., Waltz, F., Wiebcke, M., & Behrens, P. (2011). Modulated Synthesis of Zr-Based Metal-Organic Frameworks: From Nano to Single Crystals. Chemistry - A European Journal, 17(24), 6643-6651. doi:10.1002/chem.20100321

ALEVIN - A framework to develop, compare, and analyze virtual network embedding algorithms

Network virtualization is recognized as an enabling technology for the Future Internet. Applying virtualization of network resources leads to the problem of mapping virtual resources to physical resources, known as “Virtual Network Embedding” (VNE). Several algorithms attempting to solve this problem have been discussed in the literature, so far. However, comparison of VNE algorithms is hard, as each algorithm focuses on different criteria. To that end, we introduce a framework to compare different algorithms according to a set of metrics, which allow to evaluate the algorithms and compute their results on a given scenario for arbitrary parameters.Peer ReviewedPostprint (published version

An experiment-based method for parameter identification of a reduced multiscale parametric viscoelastic model of a laminated composite beam

Usual CAE tools simulate the behavior of composite parts from models considering the structures as being homogenized. Such approach reveals itself not to be effective when the engineer aims at determining the number of plies and the material characteristics of each ply to aim a specific dynamic behavior. To reply to this problem, we developed a multi-scale model that explicitly integrates the different design parameters of the composite structure being considered at different scales: the number of plies, the orthotropic law of each ply and the characteristics of each interface between the plies made by the matrix. This paper is detailing the method that we developed to lead to our multi-scale and parametric model. This method is coupled to an experimental approach that allows specific variables named fractional variables to be identified. These variables add to the detailed representation of the dynamic capacities of the laminated composite beams that led our study. In the case of our composite beams, the effect of damping due to the ply-interface behavior is significant, and consequently we dealt with the viscoelastic response of the laminated composite beam under dynamic load. As a result, the strategy of simulation based on our reduced, viscoelastic and multi-scale beam model is presented: solutions with low computational resources may be obtained. Keywords Fast simulation for CAE · Reduced model · Multi-scale model · viscoelastic behavior · Model parametrization · Method based on numerical and experimental approach List of symbols E Young's modulus (MPa) G Shear modulus = G 0 (MPa) v Poisson's ratio l Beam length (m) h Beam height (m) w Beam width (m) u Direction x B Xavier Fische