Spatial rogue waves in photorefractive SBN crystals

We report on the excitation of large-amplitude waves, with a probability of around 1% of total peaks, on a photorefractive SBN crystal by using a simple experimental setup at room temperature. We excite the system using a narrow Gaussian beam and observe different dynamical regimes tailored by the value and time rate of an applied voltage. We identify two main dynamical regimes: a caustic one for energy spreading and a speckling one for peak emergence. Our observations are well described by a two-dimensional Schr\"odinger model with saturable local nonlinearity.Comment: 4 pages, 4 figure

New Transition Wedge Design Composed by Prefabricated Reinforced Concrete Slabs

[EN] Important track degradation occurs in structure-embankment transitions, in which an abrupt change in track vertical stiffness arises, leading to a reduction in passengers comfort and safety. Although granular wedges are suggested by different railroad administrations as a solution to avoid these problems, they present some disadvantages which may affect track long-term performance. In this paper, a new solution designed with prefabricated reinforced concrete slabs is proposed. The aim of this solution is to guarantee a continuous and gradual track vertical stiffness transition in the vicinity of structures, overcoming granular wedges disadvantages. The aim of this study is to assess the performance of the novel wedge design by means of a 3-D FEM model and to compare it with the current solution.Real Herráiz, JI.; Zamorano-Martín, C.; Real-Herraiz, TP.; Morales-Ivorra, S. (2016). New Transition Wedge Design Composed by Prefabricated Reinforced Concrete Slabs. Latin American Journal of Solids and Structures. 13(8):1431-1449. doi:10.1590/1679-78252556S14311449138Gallego Giner, I., & López Pita, A. (2009). Numerical simulation of embankment—structure transition design. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 223(4), 331-343. doi:10.1243/09544097jrrt234Gallego, I., Muñoz, J., Rivas, A., & Sánchez-Cambronero, S. (2011). Vertical Track Stiffness as a New Parameter Involved in Designing High-Speed Railway Infrastructure. Journal of Transportation Engineering, 137(12), 971-979. doi:10.1061/(asce)te.1943-5436.0000288Insa, R., Salvador, P., Inarejos, J., & Roda, A. (2011). Analysis of the influence of under sleeper pads on the railway vehicle/track dynamic interaction in transition zones. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 226(4), 409-420. doi:10.1177/0954409711430174Li, D., & Davis, D. (2005). Transition of Railroad Bridge Approaches. Journal of Geotechnical and Geoenvironmental Engineering, 131(11), 1392-1398. doi:10.1061/(asce)1090-0241(2005)131:11(1392)Pita, A. L., Teixeira, P. F., & Robuste, F. (2004). High speed and track deterioration: The role of vertical stiffness of the track. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 218(1), 31-40. doi:10.1243/095440904322804411Molatefi, H., & Izadbakhsh, S. (2013). Continous rail absorber design using decay rate calculation in FEM. Structural Engineering and Mechanics, 48(4), 455-466. doi:10.12989/sem.2013.48.4.455Montalbán, L., Real, J., & Real, T. (2012). Mechanical characterization of railway structures based on vertical stiffness analysis and railway substructure stress state. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 227(1), 74-85. doi:10.1177/0954409712452348Montalbán Domingo, L., Real Herraiz, J. I., Zamorano, C., & Real Herraiz, T. (2014). Design of a new high lateral resistance sleeper and performance comparison with conventional sleepers in a curved railway track by means of finite element models. Latin American Journal of Solids and Structures, 11(7), 1238-1250. doi:10.1590/s1679-78252014000700009Montalbán Domingo, L., Zamorano Martín, C., Palenzuela Avilés, C., & Real Herráiz, J. I. (2014). Analysis of the Influence of Cracked Sleepers under Static Loading on Ballasted Railway Tracks. The Scientific World Journal, 2014, 1-10. doi:10.1155/2014/363547Real, J. I., Gómez, L., Montalbán, L., & Real, T. (2012). Study of the influence of geometrical and mechanical parameters on ballasted railway tracks design. Journal of Mechanical Science and Technology, 26(9), 2837-2844. doi:10.1007/s12206-012-0734-7Shan, Y., Albers, B., & Savidis, S. A. (2013). Influence of different transition zones on the dynamic response of track–subgrade systems. Computers and Geotechnics, 48, 21-28. doi:10.1016/j.compgeo.2012.09.006Shi, J., Burrow, M. P. N., Chan, A. H., & Wang, Y. J. (2012). Measurements and simulation of the dynamic responses of a bridge–embankment transition zone below a heavy haul railway line. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 227(3), 254-268. doi:10.1177/095440971246097

Role of toxin activation on binding and pore formation activity of the Bacillus thuringiensis Cry3 toxins in membranes of Leptinotarsa decemlineata (Say)

AbstractBinding and pore formation constitute key steps in the mode of action of Bacillus thuringiensis δ-endotoxins.In this work, we present a comparative analysis of toxin-binding capacities of proteolytically processed Cry3A, Cry3B and Cry3C toxins to brush border membranes (BBMV) of the Colorado potato beetle Leptinotarsa decemlineata (CPB), a major potato coleopteran-insect pest. Competition experiments showed that the three Cry3 proteolytically activated toxins share a common binding site. Also heterologous competition experiments showed that Cry3Aa and Cry3Ca toxins have an extra binding site that is not shared with Cry3Ba toxin. The pore formation activity of the three different Cry3 toxins is analysed. High pore-formation activities were observed in Cry3 toxins obtained by proteolytical activation with CPB BBMV in contrast to toxins activated with either trypsin or chymotrypsin proteases. The pore-formation activity correlated with the formation of soluble oligomeric structures. Our data support that, similarly to the Cry1A toxins, the Cry3 oligomer is formed after receptor binding and before membrane insertion, forming a pre-pore structure that is insertion-competent

Co-option of the transcription factor SALL1 in mole ovotestis formation

Changes in gene expression represent an important source for phenotypical innovation. Yet, how such changes emerge and impact the evolution of traits remains elusive. Here, we explore the molecular mechanisms associated with the development of masculinizing ovotestes in female moles. By performing comparative analyses of epigenetic and transcriptional data in mole and mouse, we identified SALL1 as a co-opted gene for the formation of testicular tissue in mole ovotestes. Chromosome conformation capture analyses highlight a striking conservation of the 3D organization at the SALL1 locus, but a prominent evolutionary turnover of enhancer elements. Interspecies reporter assays support the capability of mole-specific enhancers to activate transcription in urogenital tissues. Through overexpression experiments in transgenic mice, we further demonstrate the capability of SALL1 to induce the ectopic gene expression programs that are a signature of mole ovotestes. Our results highlight the co-option of gene expression, through changes in enhancer activity, as a prominent mechanism for the evolution of traits

Formation of giant iron oxide-copper-gold deposits by superimposed, episodic hydrothermal pulses

Iron oxide-copper-gold deposits are a globally important source of copper, gold and critical commodities. However, they possess a range of characteristics related to a variety of tectono-magmatic settings that make development of a general genetic model challenging. Here we investigate micro-textural and compositional variations in actinolite, to constrain the thermal evolution of the Candelaria iron oxide-copper-gold deposit in Chile. We identify at least two mineralization stages comprising an early 675–800 °C iron oxide-apatite type mineralization overprinted by a later copper-rich fluid at around 550–700 °C. We propose that these distinct stages were caused by episodic pulses of injection of magmatic-hydrothermal fluids from crystallizing magmas at depth. We suggest that the mineralisation stages we identify were the result of temperature gradients attributable to changes in the magmatic source, rather than variations in formation depth, and that actinolite chemistry can be used as a proxy for formation temperature in iron oxide-copper-gold systems

Editorial expression of concern: Formation of giant iron oxide-copper-gold deposits by superimposed, episodic hydrothermal pulses

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