Solution of the SU(N) Vertex Model with Non-Diagonal Open Boundaries

We diagonalize the double-row transfer matrix of the SU(N) vertex model for certain classes of non-diagonal boundary conditions. We derive explicit expressions for the corresponding eigenvectors and eigenvalues by means of the algebraic Bethe ansatz approach.Comment: 10 page

Integrable supersymmetric correlated electron chain with open boundaries

We construct an extended Hubbard model with open boundaries from a $R$-matrix based on the $U_q[Osp(2|2)]$ superalgebra. We study the reflection equation and find two classes of diagonal solutions. The corresponding one-dimensional open Hamiltonians are diagonalized by means of the Bethe ansatz approach.Comment: latex, 14 page

Reaction-controlled diffusion

The dynamics of a coupled two-component nonequilibrium system is examined by means of continuum field theory representing the corresponding master equation. Particles of species A may perform hopping processes only when particles of different type B are present in their environment. Species B is subject to diffusion-limited reactions. If the density of B particles attains a finite asymptotic value (active state), the A species displays normal diffusion. On the other hand, if the B density decays algebraically ~t^{-a} at long times (inactive state), the effective attractive A-B interaction is weakened. The combination of B decay and activated A hopping processes gives rise to anomalous diffusion, with mean-square displacement ~ t^{1-a} for a < 1. Such algebraic subdiffusive behavior ensues for n-th order B annihilation reactions (n B -> 0) with n >=3, and n = 2 for d < 2. The mean-square displacement of the A particles grows only logarithmically with time in the case of B pair annihilation (n = 2) and d >= 2 dimensions. For radioactive B decay (n = 1), the A particles remain localized. If the A particles may hop spontaneously as well, or if additional random forces are present, the A-B coupling becomes irrelevant, and conventional diffusion is recovered in the long-time limit.Comment: 7 pages, revtex, no figures; latest revised versio

The spectrum of an open vertex model based on the U_q[SU(2)] at roots of unity

We study the exact solution of an $N$-state vertex model based on the representation of the $U_q[SU(2)]$ algebra at roots of unity with diagonal open boundaries. We find that the respective reflection equation provides us one general class of diagonal $K$-matrices having one free-parameter. We determine the eigenvalues of the double-row transfer matrix and the respective Bethe ansatz equation within the algebraic Bethe ansatz framework. The structure of the Bethe ansatz equation combine a pseudomomenta function depending on a free-parameter with scattering phase-shifts that are fixed by the roots of unity and boundary variables.Comment: 21 page

Exact solution and finite size properties of the Uq[osp(2∣2m)]U_{q}[osp(2|2m)] vertex model

We have diagonalized the transfer matrix of the $U_{q}[osp(2|2m)]$ vertex model by means of the algebraic Bethe ansatz method for a variety of grading possibilities. This allowed us to investigate the thermodynamic limit as well as the finite size properties of the corresponding spin chain in the massless regime. The leading behaviour of the finite size corrections to the spectrum is conjectured for arbitrary $m$. For $m=1$ we find a critical line with central charge $c=-1$ whose exponents vary continuously with the $q$-deformation parameter. For $m\geq 2$ the finite size term related to the conformal anomaly depends on the anisotropy which indicates a multicritical behaviour typical of loop models.Comment: 40 pages, 8 figures, late

Influence of Phragmites australis on the seasonal evolution of biogeochemical conditions (pH/Eh) and N cycling in eutrophic wetlands

[SPA] El objetivo del trabajo fue evaluar en qué medida humedales eutrofizados, en presencia y ausencia de Phragmites australis, actúan como depuradores de NO3- y productores de N2O (gas de efecto invernadero). Para ello se realizó un experimento en mesocosmos con suelo y plantas de Phragmites, que se sometieron a seis períodos de inundación-desecación durante doce meses con aguas de distinta composición: alta carga (200 mg·L-1 NO3-) y baja carga (20 mg·L-1 NO3-) de nutrientes. Los tratamientos ensayados fueron: sin planta+baja carga; sin planta+alta carga; con planta+baja carga; con planta+alta carga. Se monitorizó Eh y pH, y se analizó la concentración de NO3- y NH4+ en la solución edáfica así como el N2O desprendido a la atmósfera. Todos los tratamientos fueron efectivos en la retirada de NO3- del agua (>70%) lo que acarreó la emisión de elevadas cantidades de N2O a la atmósfera. Phragmites contribuyó a reducir las emisiones de N2O durante las fases de secado al favorecer la retirada de NO3- del agua y disminuir su disponibilidad para ser transformado en gas vía desnitrificación. Por tanto, la presencia de planta en los suelos de los humedales puede contribuir a que se reduzca la emisión de N2O a la atmósfera. [ENG] The aim of the study was to assess to what extend eutrophic wetlands, with and without Phragmites australis, act as sinks of NO3- and as sources of N2O (greenhouse gas). A one-year mesocosms experiment, with alternating flooding-drying conditions, was performed with soil and plants of Phragmites. Two types of water were used: one with high nutrient load (200 mg·L-1 NO3-) and another one with low nutrient load (20 mg·L-1 NO3-). The treatments assayed were: no plant+low nutrient content; no plant+high nutrient content; plant+low nutrient content; plant+high nutrient content. The Eh and pH were monitored, and the concentration of NO3- and NH4+ in the soil solution and of evolved N2O were analyzed. All the treatments were effective in the removal of NO3- from water (>70%), leading to the emission of high amounts of N2O into the atmosphere. The presence of Phragmites favored lower N2O emissions mainly during drying phases due to a higher reduction of NO3- concentrations in water, decreasing its availability to be transformed into gas via denitrification. Therefore, the presence of plant in wetland soils may contribute to reduce the emission of N2O into the atmosphere.Proyecto financiado por el Ministerio de Ciencia e Innovación (Referencia CGL2010-20214)

Baterias para una movilidad sostenible: avances, retos y perspectiva

La aplicación de baterías acopladas a sistemas de conversión de energía renovable en las ciudades ayudará en gran medida a superar algunos de los retos tecnológicos para la electrificación de la red y el transporte, como la difícil accesibilidad a puntos de carga, y de coste, mejorando sus capacidades técnicas y haciendo que el sistema energético a nivel global sea más sostenible. Además, su aplicación tendrá un efecto inmediato en la salud de los ciudadanos debido a la disminución de las emisiones de gases de efecto invernadero a la atmósfera, así como otros contaminantes. A continuación, presentamos una revisión de los esfuerzos recientes para desarrollar nuevas tecnologías avanzados para las futuras baterías sostenibles. También destacaremos las estrategias actuales de reciclado de baterías que se aplican hacia un futuro con cero emisiones de carbono y basado en el concepto de economía circular. The application of batteries coupled to renewable energy conversion systems in cities will greatly help to overcome some of the technological challenges for grid electrification and transport, such as difficult accessibility to charging points, and cost, by improving their technical capabilities and making the energy system globally more sustainable. Furthermore, its implementation will have an immediate effect on citizens'' health due to the reduction of greenhouse gas emissions into the atmosphere, as well as other pollutants. Below is a review of recent efforts to develop new advanced technologies for future sustainable batteries. We will also highlight current battery recycling strategies that are being implemented towards a zero-carbon future based on the concept of the circular economy

Analytical validation of an automated assay for the measurement of adenosine deaminase (ADA) and its isoenzymes in saliva and a pilot evaluation of their changes in patients with SARS-CoV-2 infection

Objectives The aim of the present study was to validate a commercially available automated assay for the measurement of total adenosine deaminase (tADA) and its isoenzymes (ADA1 and ADA2) in saliva in a fast and accurate way, and evaluate the possible changes of these analytes in individuals with SARS-CoV-2 infection. Methods The validation, in addition to the evaluation of precision and accuracy, included the analysis of the effects of the main procedures that are currently being used for SARS-CoV-2 inactivation in saliva and a pilot study to evaluate the possible changes in salivary tADA and isoenzymes in individuals infected with SARS-CoV-2. Results The automated assay proved to be accurate and precise, with intra- and inter-assay coefficients of variation below 8.2%, linearity under dilution linear regression with R2 close to 1, and recovery percentage between 80 and 120% in all cases. This assay was affected when the sample is treated with heat or SDS for virus inactivation but tolerated Triton X-100 and NP-40. Individuals with SARS-CoV-2 infection (n=71) and who recovered from infection (n=11) had higher mean values of activity of tADA and its isoenzymes than healthy individuals (n=35). Conclusions tADA and its isoenzymes ADA1 and ADA2 can be measured accurately and precisely in saliva samples in a rapid, economical, and reproducible way and can be analyzed after chemical inactivation with Triton X-100 and NP-40. Besides, the changes observed in tADA and isoenzymes in individuals with COVID-19 open the possibility of their potential use as non-invasive biomarkers in this disease

Field theoretic approach to metastability in the contact process

A quantum field theoretic formulation of the dynamics of the Contact Process on a regular graph of degree z is introduced. A perturbative calculation in powers of 1/z of the effective potential for the density of particles phi(t) and an instantonic field psi(t) emerging from the quantum formalism is performed. Corrections to the mean-field distribution of densities of particles in the out-of-equilibrium stationary state are derived in powers of 1/z. Results for typical (e.g. average density) and rare fluctuation (e.g. lifetime of the metastable state) properties are in very good agreement with numerical simulations carried out on D-dimensional hypercubic (z=2D) and Cayley lattices.Comment: Final published version; 20 pages, 5 figure