Collisional Semiclassical Aproximations in Phase-Space Representation

The Gaussian Wave-Packet phase-space representation is used to show that the expansion in powers of $\hbar$ of the quantum Liouville propagator leads, in the zeroth order term, to results close to those obtained in the statistical quasiclassical method of Lee and Scully in the Weyl-Wigner picture. It is also verified that propagating the Wigner distribution along the classical trajectories the amount of error is less than that coming from propagating the Gaussian distribution along classical trajectories.Comment: 20 pages, REVTEX, no figures, 3 tables include

Quasiparticle Properties in Effective Field Theory

The quasiparticle concept is an important tool for the description of many-body systems. We study the quasiparticle properties for dilute Fermi systems with short-ranged, repulsive interactions using effective field theory. We calculate the proper self-energy contributions at order (K_f/Lambda)^3, where Lambda is the short-distance scale that sets the size of the effective range parameters and K_f the Fermi momentum. The quasiparticle energy, width, and effective mass to order O(K_f/Lambda)^3 are derived from the calculated self-energy.Comment: 15 pages, revtex4, 4 PS figure

Three-body Faddeev Calculation for 11Li with Separable Potentials

The halo nucleus $^{11}$Li is treated as a three-body system consisting of an inert core of $^{9}$Li plus two valence neutrons. The Faddeev equations are solved using separable potentials to describe the two-body interactions, corresponding in the n-$^{9}$Li subsystem to a p$_{1/2}$ resonance plus a virtual s-wave state. The experimental $^{11}$Li energy is taken as input and the $^{9}$Li transverse momentum distribution in $^{11}$Li is studied.Comment: 6 pages, RevTeX, 1 figur

A multi-scale hierarchical framework for developing understanding of river behaviour to support river management

The work leading to this paper was funded through the European Union’s FP7 programme under Grant Agreement No. 282656 (REFORM). The framework methodology was developed within the context of Deliverable D2.1 of the REFORM programme, and all partners who contributed to the development of the four parts of this deliverable are included in the author list of this paper. More details on the REFORM framework can be obtained from part 1 of Deliverable D2.1 (Gurnell et al. 2014), which is downloadable from http://​www.​reformrivers.​eu/​results/​deliverables

Erratum Analysis of the physical and photoelectrochemical properties of c Si p a SiC H p photocathodes for solar water splitting

The photoelectrochemical (PEC) properties of sputtered aluminum doped hydrogenated amorphous silicon carbide thin films grown on p-type crystalline silicon substrates were investigated in 1 M H2SO4<i solution under chopped light illumination. Optical and structural properties of the top absorber layer were systematically assessed after post-deposition isochronical annealing treatments. Samples exhibited a noticeable improvement of the opto-electronic properties after thermal treatments. In addition, an abrupt enhancement of the photocurrent was observed reaching a saturation value of 17 mA cm(-2) at -1.75 V vs. Ag/AgCl (3.5 M KCl). In this research we propose that this enhancement effect is associated to a charge transfer kinetic mechanism influenced by surface states and the p-type substrate. The latter most likely due to the space charge region extending beyond the absorber layer reaching the substrate. Current density-potential and electrochemical impedance spectroscopy measurements in dark revealed a reduction of the SiO2 native layer at cathodic potentials higher than -1 V vs. Ag/AgCl (3.5 M KCl), which contributes to the high charge transfer kinetic of the system. We believe that these results will contribute to understand the substrate influence in the PEC performance of top absorber layers in multilayer structures for solar water splitting.This research was funded by FONDECYT (National Fund for Scientific, Technological Development and Technological Innovation) under the agreement 147-2017. The author M Mejia has been supported by the CONCYTEC Peru (National Council for Science, Technology and Technological Innovation) doctoral scholarship under the Contract Number 236-2015-FONDECYT as well as by the PUCP vicechancellorship for research (VRI, Project No. CAP-2019-3-0041/702). The authors would like to thank the Katholischer Akademischer Auslander-Dienst institution (KAAD) for the short-term grants given to conduct research internships in the Technische Universitat Ilmenau (TU Ilmenau). Finally, the authors would like to thank the German Research Foundation (DFG) (DFG-Gz: INST 273/56-1 FUGG) and the Materials Characterization Center (CAM) at PUCP, for the financial support to conduct the characterization experiments

Polychaete invader enhances resource utilization in a species-poor system

Ecosystem consequences of biodiversity change are often studied from a species loss perspective, while the effects of invasive species on ecosystem functions are rarely quantified. In this experimental study, we used isotope tracers to measure the incorporation and burial of carbon and nitrogen from a simulated spring phytoplankton bloom by communities of one to four species of deposit-feeding macrofauna found in the species-poor Baltic Sea. The recently invading polychaete Marenzelleriaarctia, which has spread throughout the Baltic Sea, grows more rapidly than the native species Monoporeia affinis, Pontoporeia femorata (both amphipods) and Macoma balthica (a bivalve), resulting in higher biomass increase (biomass production) in treatments including the polychaete. Marenzelleria incorporated and buried bloom material at rates similar to the native species. Multi-species treatments generally had higher isotope incorporation, indicative of utilization of bloom material, than expected from monoculture yields of the respective species. The mechanism behind this observed over-yielding was mainly niche complementarity in utilization of the bloom input, and was more evident in communities including the invader. In contrast, multi-species treatments had generally lower biomass increase than expected. This contrasting pattern suggests that there is little overlap in resource use of freshly deposited bloom material between Marenzelleria and the native species but it is likely that interference competition acts to dampen resulting community biomass. In conclusion, an invasive species can enhance incorporation and burial of organic matter from settled phytoplankton blooms, two processes fundamental for marine productivity