Polarization-dependent light extinction in ensembles of polydisperse, vertical semiconductor nanowires : a Mie scattering effective medium

We present an experimental and theoretical study of the angle- and polarization-dependent light extinction in random arrays of polydisperse semiconductor nanowires epitaxially grown on substrates. The specular reflectance is described by averaging the scattering properties of individual nanowires obtained from Mie theory over the diameter distribution. The complex effective refractive index describing the propagation and attenuation of the coherent beam scattered in a forward direction is determined in the independent scattering approximation and used to calculate the angle- and polarization-dependent reflectance. Our measurements demonstrate the highly anisotropic scattering in ensembles of aligned nanowires

HMGXB4 targets Sleeping Beauty transposition to vertebrate germinal stem sells

Transposons are parasitic genetic elements that frequently hijack key cellular processes of the host. HMGXB4 is a Wnt signalling-associated HMG-box protein, previously identified as a transcriptional regulating host factor of Sleeping Beauty (SB) transposition. Here, we establish that HMGXB4 is highly expressed from the zygote stage, and declines after transcriptional genome activation. Nevertheless, HMGXB4 is activated by its own promoter at 4-cell stage, responding to the parental-to-zygotic transition, marks stemness, and maintains its expression during germ cell specification. The HMGXB4 promoter is located at an active chromatin domain boundary. As a vertebrate-specific modulator of SETD1A and NuRF complexes, HMGXB4 links histone H3K4 methyltransferase- and ATP-dependent nucleosome remodelling activities. The expression of HMGXB4 is regulated by the KRAB-ZNF/TRIM28 epigenetic repression machinery. A post-transcriptional modification by SUMOylation diminishes its transcriptional activator function and regulates its nucleolar trafficking. Collectively, HMGXB4 positions SB transposition into an elaborate stem cell-specific transcriptional regulatory mechanism that is active during early embryogenesis and germline development, thereby potentiating heritable transposon insertions in the germline

Silicon Mie Resonators for Highly Directional Light Emission from monolayer MoS2

Controlling light emission from quantum emitters has important applications ranging from solid-state lighting and displays to nanoscale single-photon sources. Optical antennas have emerged as promising tools to achieve such control right at the location of the emitter, without the need for bulky, external optics. Semiconductor nanoantennas are particularly practical for this purpose because simple geometries, such as wires and spheres, support multiple, degenerate optical resonances. Here, we start by modifying Mie scattering theory developed for plane wave illumination to describe scattering of dipole emission. We then use this theory and experiments to demonstrate several pathways to achieve control over the directionality, polarization state, and spectral emission that rely on a coherent coupling of an emitting dipole to optical resonances of a Si nanowire. A forward-to-backward ratio of 20 was demonstrated for the electric dipole emission at 680 nm from a monolayer MoS2 by optically coupling it to a Si nanowire

Social times, reproduction and social inequality at work : contrasts and comparative perspectives between countries

Production of INCASI Project H2020-MSCA-RISE-2015 GA 691004If the focus is placed specifically on the problem of work and family, the daily life of people and their use of time are a main problem. This time is expressed in both freely available time, which is related to activities, and time of the productive and reproductive sphere. This chapter considers work in a broad sense and takes into account the sexual division of labour. Specifically, this chapter will explore transformations in time use and social inequality in unpaid work. For this purpose, a comparative analysis of time-use surveys will be used, analysing the time spent, and the time dedicated to household chores in Chile, Argentina, Uruguay and Spain. From an analytical viewpoint, the analysis will place social reproduction at the centre of the socio-economic system, showing that the economic crisis has affected women and men differently, and that in both Europe and Latin America the family pattern is being replaced by a dominant family model of a male provider and a double presence of women. The large-scale incorporation of women into the labour market has emphasised the role that women assume in the domestic sphere perpetuating gender segregation in employment and in domestic and care work

The role of Drosophila boundary elements and insulators in chromatin mobility

The question how the structure influences the gene function is one of the most important problems in nuclear architecture research. Molecular genetic evidences suggest that eukaryotic chromatin is organized into domains that separate neighboring genes physically and functionally. Specialized DNA elements called chromatin boundaries or insulators have been identified that delimit genome regions of distinct chromatin structure and gene activity. Although the exact mechanism underlying insulator activity is not known, recent studies suggest that regulated assembly of chromatin boundaries result in higher order protein complexes and organization of the chromatin architecture. The thesis project consisted of the generation of flylines containing insulator elements combined with LacO/LacI-GFP reporter system in order to investigate the influence of these elements on the mobility of chromatin sequences

The role of Drosophila boundary elements and insulators in chromatin mobility

The question how the structure influences the gene function is one of the most important problems in nuclear architecture research. Molecular genetic evidences suggest that eukaryotic chromatin is organized into domains that separate neighboring genes physically and functionally. Specialized DNA elements called chromatin boundaries or insulators have been identified that delimit genome regions of distinct chromatin structure and gene activity. Although the exact mechanism underlying insulator activity is not known, recent studies suggest that regulated assembly of chromatin boundaries result in higher order protein complexes and organization of the chromatin architecture. The thesis project consisted of the generation of flylines containing insulator elements combined with LacO/LacI-GFP reporter system in order to investigate the influence of these elements on the mobility of chromatin sequences