Resonances in low-energy electron scattering from <i>para</i>-benzoquinone

We present detailed ab initio scattering calculations for electron collisions with para-benzoquinone. The R-matrix method has been used to study elastic and electronically inelastic scattering. We have identified 25 resonances of shape, Feshbach, core-excited shape and mixed character between 0 and 8 eV. Agreement of our resonance spectrum with existing literature is discussed, in particular that of the low-lying resonances that participate in the photodetachment process. Integral elastic and total inelastic cross sections are also presented

Low-energy electron collisions with water: elastic and rotationally inelastic scattering

Differential, integral and momentum transfer cross sections for the vibrationally elastic and rotationally inelastic scattering of electrons from water at low collision energies (E < 7 eV) are reported. The R-matrix method is used to compute the body-fixed T-matrices while the scattering calculations are performed within the fixed-nuclei approximation corrected with the standard Born-closure formula. Our calculations are compared with the very recent experimental results of Cho et al (2003 Radiat. Phys. Chem. 68 115). The differential and momentum transfer cross sections are in good agreement with the experimental results. The relative contribution of the rotationally inelastic processes is investigated in some detail. In particular, the importance of the pure elastic process at very low energy is emphasized

Cytoskeletal turnover and Myosin contractility drive cell autonomous oscillations in a model of Drosophila Dorsal Closure

Oscillatory behaviour in force-generating systems is a pervasive phenomenon in cell biology. In this work, we investigate how oscillations in the actomyosin cytoskeleton drive cell shape changes during the process of Dorsal Closure, a morphogenetic event in Drosophila embryo development whereby epidermal continuity is generated through the pulsatile apical area reduction of cells constituting the amnioserosa (AS) tissue. We present a theoretical model of AS cell dynamics by which the oscillatory behaviour arises due to a coupling between active Myosin-driven forces, actin turnover and cell deformation. Oscillations in our model are cell-autonomous and are modulated by neighbour coupling, and our model accurately reproduces the oscillatory dynamics of AS cells and their amplitude and frequency evolution. A key prediction arising from our model is that the rate of actin turnover and Myosin contractile force must increase during DC in order to reproduce the decrease in amplitude and period of cell area oscillations observed in vivo. This prediction opens up new ways to think about the molecular underpinnings of AS cell oscillations and their link to net tissue contraction and suggests the form of future experimental measurements.Comment: 17 pages, 6 figures; added references, modified and corrected Figs. 1 and 3, corrected typos, expanded discussio

Electron Collisions with Molecules and Molecular Clusters

State-of-the art computational studies of electron collisions with molecules and small molecular clusters are illustrated with results obtained from the application of the R-matrix method and the UKRMol/UKRMol+ suites. High-level calculations of electronic excitation cross sections and core-excited resonances, mainly of core-excited shape character, show excellent agreement with experiment for mid-size molecules like pyrimidine and thiophene. Simpler calculations are paving the way for an in-depth understanding of the effect of hydration on resonance formation: how the shift in resonance energy depends on the characteristics of the hydrogen bond and the resonance being studied. Finally, applications of the software to a little studied process, interatomic coulombic electron capture are also illustrated

Resonances in molecules and molecular clusters

Resonances play an important role in a number of atomic and molecular processes. Identifying and characterising resonances in electron scattering is essential as they can both enhance a number of processes (e.g. electronic and vibrational excitation) and are crucial in others like dissociative electron attachment and dissociative recombination. We discuss recent theoretical studies of shape and core-excited resonances, both in isolated molecules of biological relevance and in small molecular clusters. The latter are investigated to understand the effect of the environment, in particular hydration, in electron collisions in biological matter

Más que cuidadoras: ciudadanas de nuevas dinámicas sociales

España se ha convertido en un país de atracción de población inmigrante. Ésta se incorpora en el mercado de trabajo local, siendo el ámbito del empleo en las actividades de la reproducción social uno de los más significativos. Los inmigrantes, sin embargo, no se insertan exclusivamente a sus puestos de trabajo sino que también lo hacen en los nuevos espacios de la ciudad. A través de una investigación de tipo cualitativo con empleadas y empleadoras del sector del trabajo doméstico de menores se analizan las distintas formas en que esta población inmigrante se incorpora a los nuevos ámbitos de su vida cotidiana. La ambivalencia entre las inclusiones y exclusiones que experimentan en la sociedad de destino constituye un elemento constante de las nuevas dinámicas sociales.Immigration has become a major issue in Spanish society today, and the issue of migrants entering society to perform social reproduction tasks is among the most prominent ones. Migrant populations do not only join new societies as workers but also as actors in their new city and its everyday life. There are different ways in which they become a part of new social spheres – from a spatial standpoint to an emotional one-, and this article deals with this phenomenon. The analysis is based on qualitative research conducted through interviews with employers and employees in the child care sector, and it reveals the ambivalence of social exclusion and inclusion that migrant populations experience in modern social dynamics

Care labour market and the creation of global care chains: how the reconciliation of carers take place?

En los últimos años en España se ha producido un reequilibrio en las responsabilidades del cuidado, logrado, fundamentalmente, por la introducción de nuevos actores en su realización. La realidad socio-laboral impide que las mujeres se ocupen como antaño de la crianza de los hijos, por lo que se presenta necesario delegarla en otras personas: las trabajadoras de los cuidados. Se ha generado, de esta manera, un nuevo mercado laboral con claras consecuencias para la organización de las familias involucradas. Los puestos de trabajo de cuidado se encuentran ocupados, en su mayoría, por mujeres inmigrantes quienes, además de prestar cuidados de forma remunerada, deben garantizar la atención de sus propios hijos. Muchas veces éstos permanecen en los países de origen desarrollándose de esta manera relaciones a un nivel internacional que se han dado en llamar cadenas globales de cuidado.In the last few years Spain has been developing a new equilibrium in relation to the responsibilities of care. This is based, mainly, on the introduction of new actors to take responsibility of this activity. The new socio-economic reality implies that women not longer take the solely responsibility of these functions and, therefore, it becomes necessary to delegate them to other people: the care workers. A new labour market has consequently been generated, bringing many consequences to the ways families get organized. Migrant women constitute the big majority of the labour force of this new market, and besides being care workers they can also be mothers themselves. In many occasions, their children remain in the countries of origin giving place to an international process of relations known as global care chains

Interatomic Coulombic electron capture from first principles

Interatomic Coulombic electron capture (ICEC) is an environment-assisted process in which a free electron can efficiently attach to an ion, atom or molecule by transferring the excess energy to a neighboring species. Absolute cross sections are necessary to evaluate the relative importance of this process. In this work, we employ the R-matrix method to compute ab initio these cross sections for a singly charged neon ion embedded in small helium clusters. Our results show that the ICEC cross sections are several orders of magnitude higher than anticipated and dominate other competing processes. Electron energy loss spectra on an absolute scale are provided for the Ne+@He20 cluster. Such spectra exhibit an unambiguous signature of the ICEC process. The finding is expected to stimulate experimental observations

Electron-H-3(+) collisions at intermediate energies

A new procedure is presented for the ab initio study of electron-molecule collision at energies straddling the target ionization threshold. The R-matrix with pseudostates method, which allows for the inclusion of discretized continuum states in a close-coupling expansion, is adapted to molecular targets using even-tempered basis sets. Calculations for electron collisions with the H-3(+) molecular ion provide converged polarizabilities, electronic excitation and ionization cross sections

El mercado de trabajo de los cuidados y la creación de las cadenas globales de cuidado: ¿cómo concilian las cuidadoras?

In the last few years Spain has been developing a new equilibrium in relation to the responsibilities of care. This is based, mainly, on the introduction of new actors to take responsibility of this activity. The new socio-economic reality implies that women not longer take the solely responsibility of these functions and, therefore, it becomes necessary to delegate them to other people: the care workers. A new labour market has consequently been generated, bringing many consequences to the ways families get organized. Migrant women constitute the big majority of the labour force of this new market, and besides being care workers they can also be mothers themselves. In many occasions, their children remain in the countries of origin giving place to an international process of relations known as global care chains.En los últimos años en España se ha producido un reequilibrio en las responsabilidades del cuidado, logrado, fundamentalmente, por la introducción de nuevos actores en su realización. La realidad socio-laboral impide que las mujeres se ocupen como antaño de la crianza de los hijos, por lo que se presenta necesario delegarla en otras personas: las trabajadoras de los cuidados. Se ha generado, de esta manera, un nuevo mercado laboral con claras consecuencias para la organización de las familias involucradas. Los puestos de trabajo de cuidado se encuentran ocupados, en su mayoría, por mujeres inmigrantes quienes, además de prestar cuidados de forma remunerada, deben garantizar la atención de sus propios hijos. Muchas veces éstos permanecen en los países de origen desarrollándose de esta manera relaciones a un nivel internacional que se han dado en llamar cadenas globales de cuidado