Numerical modeling of biochemical transport processes with heterogeneous source terms. Application to wastewater models

Subsurface flow constructed wetlands are one of the different types of wastew- ater treatments used nowadays. There, water is treated by physical, biological and chem- ical processes while flowing through a porous media. Many aspects of detailed processes which take place there are not well-known. In fact, a key point of their behavior is that simultaneously aerobic and anaerobic conditions take place in different parts of the do- main. Mathematically the problem is a Convection – Diffusion – Reaction system of equations, highly coupled because of the nonlinear reaction term that models the biochem- ical processes. An stabilized Galerkin formulation is used for spatial discretization, and the Runge-Kutta-Fehlberg 4-5 scheme is used for time integration. Homogeneous exam- ples with and without oxygen entrance throughout all domain have been used to check the numerical performance of the approach. The Activated Sludge Model No.1 (ASM1) and a six–equations model based on it are used as examples of complex reaction models. Two dimensional examples with oxygen entrance in just part of the domain have been also computed. It has been check that under horizontal low–velocity conditions a discontinuity in oxygen vertical profile is found, even if continuous transition in oxygen entrance is imposed. In this situation, classical convection stabilization has shown to be usefulness to smooth discontinuities produced by source terms. Further numerical improvements needed are indicated, as well as an extension to more realistic biochemical models for subsurface flow constructed wetlandsPeer ReviewedPostprint (published version

Theoretical study of Ga-based nanowires and the interaction of Ga with single-wall carbon nanotubes

Gallium displays physical properties which can make it a potential element to produce metallic nanowires and high-conducting interconnects in nanoelectronics. Using first-principles pseudopotential plane method we showed that Ga can form stable metallic linear and zigzag monatomic chain structures. The interaction between individual Ga atom and single-wall carbon nanotube (SWNT) leads to a chemisorption bond involving charge transfer. Doping of SWNT with Ga atom gives rise to donor states. Owing to a significant interaction between individual Ga atom and SWNT, continuous Ga coverage of the tube can be achieved. Ga nanowires produced by the coating of carbon nanotube templates are found to be stable and high conducting.Comment: 8 pages, 8 figure

Mesozoic structural inheritance in the Cenozoic evolution of the central Catalan Coastal Ranges (western Mediterranean): Structural and magnetotelluric analysis in the Gaià-Montmell High

The control exerted by the Mesozoic basin configuration on the Cenozoic tectonic evolution of the Catalan Coastal Ranges has been frequently recognized as a key factor to explain its present-day structure. However, details of this structural inheritance and its evolution through geological time is still under discussion. In this work we present two structural cross-sections based on fieldwork, well and magnetotelluric data in order to illustrate the structural styles and tectonic evolution of the Gaià-Montmell High. Here, the Montmell Fault not only constitutes the SW segment of one of the major Neogene faults in the Catalan Coastal Ranges (the Montmell-Vallès Fault System), but also the NW limit of a Late Jurassic-Early Cretaceous extensional basin(the Montmell-Garraf Basin), facts that denote a major role of this fault in the tectonic evolution of the area. The present-day structure of the Gaià-Montmell High resulted, therefore, from two successive episodes of inversion during the Cenozoic. The first one reactivated the Montmell Fault as compressional during the Paleogene. As a result, and among other inversion-related structures, the Gaià-El Camp Thrust developed sa major NW-directed basement footwall shortcut. Later on, the previously formed compressional structure during the Paleogene became reactivated as extensional during the Neogene. During this phase, the reactivation of the Montmell Fault looks limited and, hence, the extension is transmitted to the Baix Penedès Fault. The reactivation of the Gaià-El Camp Thrust is also manifest in the development of an array of extensional faults in the backlimb of the Carme-Cabra Anticline that corresponds to the NE-end of El Camp Fault. This episode of negative inversion developed accommodation zones between the four major faults present in the area ( Vallès-Penedès, Montmell, El Camp and Baix Penedès faults) that are characterized by the presence of relay ramps with breaching faults

The Duration of the Trial Influences the Effects of Mineral Deficiency and the Effective Phytase Dose in Broilers' Diets

[EN] Two trials varying in duration (short- and long-term) were conducted to evaluate the effects of providing deficient (NC) or sufficient (PC) Ca and P levels, and different doses of a new phytase (250, 500, and 1000 FTU/kg feed), in broiler feed on growth performance, nutrient digestibility and retention, and tibia mineralization. A total of 80 and 490 male chicks (Ross) of 21 and 1 days of age were used in the short- and long-term trials, respectively. In the long-term trial, chicks fed NC diets showed a lower (p < 0.05) average daily gain and feed intake compared to chicks fed PC and a greater (p < 0.05) feed conversion ratio compared to 500 and 1000 FTU/kg feed during the starting period. Regarding the effects on minerals¿ and nutrients¿ coefficients of retention, animals fed NC showed a significantly higher digestibility for P than those fed the PC diet in the long-term trial. Additionally, feeding 250 to 500 FTU/kg diets increased most of the nutrients¿ digestibility in the short-term but only P digestibility in the long-term trial. Tibia mineralization increased linearly with phytase addition (p < 0.05) only in the long-term trial. In conclusion, the effects of dietary mineral and phytase levels on growth performance are more noticeable in young animals. In addition, the duration of the trial is key due to a possible adaptation phenomenon of birds to low P supplementary levels.This research was funded by the Centre for the Development of Industrial Technology (CDTI), supported by the Ministry of Science and Innovation, Government of Spain.Javadi, M.; Cerisuelo, A.; Cambra López, M.; Macias-Vidal, J.; Donadeu, A.; Dupuy, J.; Carpintero, L.... (2022). The Duration of the Trial Influences the Effects of Mineral Deficiency and the Effective Phytase Dose in Broilers' Diets. Animals. 12(11):1-19. https://doi.org/10.3390/ani12111418119121

Single quantum dot emission at telecom wavelengths from metamorphic InAs/InGaAs nanostructures grown on GaAs substrates

3 figuras, 3 páginas.We report on the growth by molecular beam epitaxy and the study by atomic force microscopy and photoluminescence of low density metamorphic InAs/InGaAs quantum dots. subcritical InAs coverages allow to obtain 108 cm−2 dot density and metamorphic InxGa1−xAs (x = 0.15,0.30) confining layers result in emission wavelengths at 1.3 μm. We discuss optimal growth parameters and demonstrate single quantum dot emission up to 1350 nm at low temperatures, by distinguishing the main exciton complexes in these nanostructures. Reported results indicate that metamorphic quantum dots could be valuable candidates as single photon sources for long wavelength telecom windows.the financial support of the Generalitat Valenciana and the Spanish Ministry of Science (Project Nos. PROMETEO/2009/074 and TEC2008-06756-C03-03, respectively).Peer reviewe

Size dependent carrier thermal escape and transfer in bimodally distributed self assembled InAs/GaAs quantum dots

We have investigated the temperature dependent recombination dynamics in two bimodally distributed InAs self assembled quantum dots samples. A rate equations model has been implemented to investigate the thermally activated carrier escape mechanism which changes from exciton-like to uncorrelated electron and hole pairs as the quantum dot size varies. For the smaller dots, we find a hot exciton thermal escape process. We evaluated the thermal transfer process between quantum dots by the quantum dot density and carrier escape properties of both samples. © 2012 American Institute of Physics.We gratefully acknowledge the financial support of the Generalitat Valenciana, Comunidad Autnoma de Madrid and the Spanish Ministry Projects Nos. PROMETEO/2009/074, S2009ESP-1503 and TEC-2008-06756-C03-03, TEC2011-29120-C05-04/01. One of the authors D. Rivas thanks the Ministry of Science for his FPI fellowship. The AFM characterization has been carried out at CIM, University of Parma, Italy.Peer Reviewe

Solving Man-Induced Large-Scale Conservation Problems: The Spanish Imperial Eagle and Power Lines

[Background] Man-induced mortality of birds caused by electrocution with poorly-designed pylons and power lines has been reported to be an important mortality factor that could become a major cause of population decline of one of the world rarest raptors, the Spanish imperial eagle (Aquila adalberti). Consequently it has resulted in an increasing awareness of this problem amongst land managers and the public at large, as well as increased research into the distribution of electrocution events and likely mitigation measures.[Methodology/Principal Findings] We provide information of how mitigation measures implemented on a regional level under the conservation program of the Spanish imperial eagle have resulted in a positive shift of demographic trends in Spain. A 35 years temporal data set (1974–2009) on mortality of Spanish imperial eagle was recorded, including population censuses, and data on electrocution and non-electrocution of birds. Additional information was obtained from 32 radio-tracked young eagles and specific field surveys. Data were divided into two periods, before and after the approval of a regional regulation of power line design in 1990 which established mandatory rules aimed at minimizing or eliminating the negative impacts of power lines facilities on avian populations. Our results show how population size and the average annual percentage of population change have increased between the two periods, whereas the number of electrocuted birds has been reduced in spite of the continuous growing of the wiring network.[Conclusions] Our results demonstrate that solving bird electrocution is an affordable problem if political interest is shown and financial investment is made. The combination of an adequate spatial planning with a sustainable development of human infrastructures will contribute positively to the conservation of the Spanish imperial eagle and may underpin population growth and range expansion, with positive side effects on other endangered species.P. López-López was supported by FPU grant of the Spanish Ministerio de Educación (reference AP2005-0874) and wrote this paper during a pre-doctoral stay at Doñana Biological Station (CSIC) in Sevilla, Spain. The funders of this study (Spanish Ministry of Education, Natural Research Ltd. and Junta de Andalucía) had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewe

Post-fledging dependence period and onset of natal dispersal in Bearded Vultures (Gypaetus barbatus): new insights from GPS satellite telemetry.

Utilizamos telemetría satelital para estudiar el periodo de dependencia post emplumamiento de tres individuos silvestres y seis individuos cautivos de Gypaetus barbatus. El primer vuelo tuvo lugar cuando los pollos tenían 126 ± 7 días de edad (rango  =  111-134 días) y el inicio de la dispersión ocurrió a los 193 ± 40 días desde el primer vuelo (rango  =  143-231 días). Los jóvenes permanecieron en sus áreas natales (o de liberación, en el caso de aves criadas en cautiverio) durante los primeros dos meses desde la fecha de emplumamiento. Luego, comenzaron a incrementar progresivamente la distancia a sus áreas natales; durante este tiempo, la mayoría de los desplazamientos de larga distancia (>15 km) tuvieron lugar antes del mediodía. Los tamaños de las áreas de acción registrados en este estudio fueron superiores a los descritos con anterioridad para la especie, principalmente debido a la diferencia en los métodos de rastreo empleados: la telemetría satelital permitió la detección de movimientos de larga distancia más allá del rango de medición del rastreo por radio convencional. Finalmente, la adquisición de la independencia (i.e., emancipación) se solapó con la siguiente temporada de cría de los adultos

Synergistic activation of AMPK prevents from polyglutamine-inducedtoxicity inCaenorhabditis elegans

11 páginas, 4 figuras. Supplementary material related to this article can be found, in the online version, at doi: https://doi.org/10.1016/j.phrs.2020.105105.Expression of abnormally long polyglutamine (polyQ) tracks is the source of a range of dominant neurodegenerative diseases, such as Huntington disease. Currently, there is no treatment for this devastating disease, although some chemicals, e.g., metformin, have been proposed as therapeutic solutions. In this work, we show that metformin, together with salicylate, can synergistically reduce the number of aggregates produced after polyQ expression in Caenorhabditis elegans. Moreover, we demonstrate that incubation polyQ-stressed worms with low doses of both chemicals restores neuronal functionality. Both substances are pleitotropic and may activate a range of different targets. However, we demonstrate in this report that the beneficial effect induced by the combination of these drugs depends entirely on the catalytic action of AMPK, since loss of function mutants of aak-2/AMPKα2 do not respond to the treatment. To further investigate the mechanism of the synergetic activity of metformin/salicylate, we used CRISPR to generate mutant alleles of the scaffolding subunit of AMPK, aakb-1/AMPKβ1. In addition, we used an RNAi strategy to silence the expression of the second AMPKβ subunit in worms, namely aakb-2/AMPKβ2. In this work, we demonstrated that both regulatory subunits of AMPK are modulators of protein homeostasis. Interestingly, only aakb-2/AMPKβ2 is required for the synergistic action of metformin/salicylate to reduce polyQ aggregation. Finally, we showed that autophagy acts downstream of metformin/salicylate-related AMPK activation to promote healthy protein homeostasis in worms.We thank the CGC, funded by the NIH Office of ResearchInfrastructure Programs (P40 OD010440), for worm strains. [...] RPVMis aMiguel Servet type IIresearcher (CPII16/00004) funded by Institutode Salud Carlos III (ISCIII, Madrid, Spain). Grants from the ISCIII wereused to perform this work (PI14/00949 and PI17/00011). All grantsfrom ISCIII are co-financed by the European Development RegionalFund”A way to achieve Europe”(ERDF). JBY holds a grant from theGeneralitat Valenciana and the European Social Fund (ACIF/2019/249). Some equipment used in this work has been funded in partnershipbetween the Generalitat Valenciana (Conselleria de Sanitat I SalutPública, Valencian Community, Spain) and European Funds (ERDF/FSE), through the call "Improvement of research infrastructures for rarediseases”CV FEDER 2014-2020. This work has been partially supportedby a grant from the Fundació Telemarató de la TV3 (Reference 559),which covered the work of MDS. The funds from the ISCIII are partiallysupported by the European Regional Development Fund. RPVM is also aMarie Curie fellow (CIG322034, EU). This work has been partiallysupported by a grant from the CIBERER (ACCI2016), a grant from theFundación Ramón Areces (CIVP19S8119) and anAyuda Miguel Gilgrantto RPVM (VII Convocatoria Ayudas a la Investigación MHER, 2019Peer reviewe

Quantum point contact on graphite surface

The conductance through a quantum point contact created by a sharp and hard metal tip on the graphite surface has features which to our knowledge have not been encountered so far in metal contacts or in nanowires. In this paper we first investigate these features which emerge from the strongly directional bonding and electronic structure of graphite, and provide a theoretical understanding for the electronic conduction through quantum point contacts. Our study involves the molecular-dynamics simulations to reveal the variation of interlayer distances and atomic structure at the proximity of the contact that evolves by the tip pressing toward the surface. The effects of the elastic deformation on the electronic structure, state density at the Fermi level, and crystal potential are analyzed by performing self-consistent-field pseudopotential calculations within the local-density approximation. It is found that the metallicity of graphite increases under the uniaxial compressive strain perpendicular to the basal plane. The quantum point contact is modeled by a constriction with a realistic potential. The conductance is calculated by representing the current transporting states in Laue representation, and the variation of conductance with the evolution of contact is explained by taking the characteristic features of graphite into account. It is shown that the sequential puncturing of the layers characterizes the conductance.Comment: LaTeX, 11 pages, 9 figures (included), to be published in Phys. Rev. B, tentatively scheduled for 15 September 1998 (Volume 58, Number 12