Relations between the diffusion anomaly and cooperative rearranging regions in a hydrophobically nanoconfined water monolayer

We simulate liquid water between hydrophobic walls separated by 0.5 nm, to study how the diffusion constant D_\parallel parallel to the walls depends on the microscopic structure of water. At low temperature T, water diffusion can be associated with the number of defects in the hydrogen bonds network. However, the number of defects solely does not account for the peculiar diffusion of water, with maxima and minima along isotherms. Here, we calculate a relation that quantitatively reproduces the behavior of D_\parallel, focusing on the high-T regime. We clarify how the interplay between breaking of hydrogen bonds and cooperative rearranging regions of 1-nm size gives rise to the diffusion extrema, possibly relevant for both bulk and nanoconfined water.Comment: Published version; extended references, 5 pages, 3 figure

Identifying wave packet fractional revivals by means of information entropy

Wave packet fractional revivals is a relevant feature in the long time scale evolution of a wide range of physical systems, including atoms, molecules and nonlinear systems. We show that the sum of information entropies in both position and momentum conjugate spaces is an indicator of fractional revivals by analyzing three different model systems: $(i)$ the infinite square well, $(ii)$ a particle bouncing vertically against a wall in a gravitational field, and $(iii)$ the vibrational dynamics of hydrogen iodide molecules. This description in terms of information entropies complements the usual one in terms of the autocorrelation function

Snapshot of macroalgae and fish assemblages in temperate reefs in the Southern European Atlantic Ecoregion

Most of the biodiversity studies in the South European Atlantic Shelf ecoregion are limited to shallow subtidal or intertidal habitats, while deeper reef habitats, also of relevant ecological importance, are particularly understudied. Macroalgal communities, associated fauna, and sea surface temperature were studied in deep reefs (25-30 m) at two locations in this ecoregion: Parcel, North of Portugal (41 degrees N), and Tarifa, Southern Spain (35 degrees N). Specifically, algal assemblages were assessed using biomass collection and associated ichthyofauna was assessed using visual census techniques using scuba. Seawater surface temperature was higher (>3 degrees C) in the southern region-Tarifa, compared to the northern region-Parcel. Our survey revealed 18 fish species and 23 algae species. The highest abundance of cold-water species (both macroalgae and fish species) was recorded in Parcel and warm-water species were dominant in Tarifa. In light of climate global trends, both regions might experience biodiversity shifts towards tropicalization. Current knowledge on their biodiversity is imperative to further evaluate potential shifts.info:eu-repo/semantics/publishedVersio

Quantum recurrence times in nanostructures

We compute the classical and revival times of electron currents in several bulk nanostructured, semiconductor materials. We have used a nonparabolic Schrödinger equation to model the conduction band of semiconductors. We have calculated the classical and revival periods for quantum dots of Si, Ge and InAs quantum dots. The obtained results are of the order of tenths of nanoseconds to picoseconds, which are within reach of current technologies.This work is part of the Project of I+D+i Ref. PID2020-113681GB-I00, financed by MICIN/AEI/10.13039/501100011033 and FEDER “A way to make Europe”

El sindicato en la microempresa y la pequeña empresa

La infra representación de los trabajadores en las pequeñas empresas y microempresas es una realidad que obedece a una serie de causas legales y de organización y credibilidad sindical y que, por desgracia, ocasiona graves situaciones de desamparo a ingentes cantidades de trabajadores. Se hace necesario pues, un aumento de la representatividad en estas empresas y, dado que hoy por hoy es una utopía esperar cambios legislativos en esa dirección, se debe ahondar –y ese es el fin de este trabajo– en las posibilidades que ofrece nuestro ordenamiento jurídico –sobre todo, desde el prisma de la libertad sindical– para extraer todas las oportunidades que nos conduzcan a ese fin. Para ello, se debieran tomar dos caminos: El primero el de la negociación colectiva, a través de la cual se podrían ampliar las facultades representativas de la sección sindical en la empresa y de su representante o portavoz así como también crear secciones sindicales en ámbitos que sobrepasen el centro de trabajo y/o la empresa. De igual manera, podría dotarse a las diversas comisiones con participación paritaria que contempla nuestro ordenamiento (Comisión de igualdad o Comisión paritaria del convenio colectivo, por ejemplo) de atribuciones para estar presentes en las pequeñas empresas huérfanas de representación. Como también se debiera potenciar la creación de organismos especializados en salud laboral que puedan extender su actividad a todas aquellas empresas sin representantes de un sector y territorio determinado o de comisiones representativas de los sindicatos más representativos para enfrentar las reestructuraciones empresariales. El segundo recorrido a seguir –pero que irá inextricablemente unido al anterior– sería el de posibilitar cambios de organización y estrategias de acción en el seno de los mismos sindicatos que faciliten esa representatividad, como la misma creación de secciones sectoriales que, posteriormente, deban llevarse a la negociación colectiva; o el uso sindical del cargo electivo y del crédito horario que, a la postre, también tendría que quedar plasmado en el convenio colectivo correspondiente.The under-representation of workers in small enterprises and micro-enterprises is a reality that is due to a number of legal grounds and credibility of Association and organization, which, unfortunately, resulting in serious situations of helplessness to vast amounts of workers. Becomes necessary as, an increase of representation in these companies and, given that today is a utopia expected changes in legislation in this direction, it must deepen - and that is the end of this work - in the possibilities offered by our legal system - above all, through the prism of the freedom of Association - to remove all the opportunities that lead us to that end. Therefore you should take two paths: the first collective bargaining, through which you could extend the powers of the representative of the trade union section in the enterprise and its representative or spokesperson as well as also create unions in areas that exceed the work center and/or the company. Similarly, it could give to the various committees with joint participation that includes our legal system (Equality Commission) or Joint Committee of the collective agreement, for example of powers to be orphans of representation in small enterprises. As it should also promote the creation of agencies specializing in occupational health that they can extend its activity all companies without representatives of a sector and specific territory or commissions representing the most representative trade unions to address the restructuring. The second route to follow - but that it will be inextricably attached to the above - would be the enabling organizational changes and strategies for action in the bosom of the same unions that facilitate that representativeness as the creation of sectoral sections which, subsequently, should lead to collective bargaining or Union use of elected office and time credit that, to the dessert, should also be reflected in the corresponding collective bargaining agreement

The τ-fixed point property for left reversible semigroups

In this article we use the generalized Gossez-Lami Dozo property and the Opial condition to study the fixed point property for left reversible semigroups in separable Banach spaces. As a consequence, some previous results will be deduced and new examples of Banach spaces satisfying the fixed point property for left reversible semigroups are shown. We will also extend some previous theorems when we consider the semigroup formed by a unique nonexpansive mapping and its iterates.Ministerio de Ciencia e InnovaciónJunta de Andalucí