Structural Modelling of Female Labour Participation and Occupation Decisions

The objective of this paper is to estimate the parameters defining female labour participation and occupation decisions. Departing from a theoretical framework, we use micro data to estimate the wage-participation elasticity in Mexico. Consistency between the selectivity-adjusted wages and the multinomial participation equations is achieved via a two-step estimation procedure following Lee (1984). We use the results of our model to test and quantify three hypotheses explaining recent increases in female labour participation in Mexico. Our results show that the observed 12 per cent increase in female labour participation in Mexico between 1994 and 2000 is explained by the combination of a negative income shock caused by the 1994-95 Peso crisis, the increase in expected wages taking place in the manufacturing sector during the post-NAFTA period and a reduction in the female reservation wage

Control of fluorescence in quantum emitter and metallic nanoshell hybrids for medical applications

We study the light emission from quantum emitter and double metallic nanoshell hybrid systems. Quantum emitters act as local sources which transmit their light efficiently due to a double nanoshell near field. The double nanoshell consists a dielectric core and two outer nanoshells

Pattern formation from consistent dynamical closures of uniaxial nematic liquid crystals

Pattern formation in uniaxial polymeric liquid crystals is studied for different dynamic closure approximations. Using the principles of mesoscopic non-equilibrium thermodynamics in a mean-field approach, we derive a Fokker-Planck equation for the single-particle non-homogeneous distribution function of particle orientations and the evolution equations for the second and fourth order orientational tensor parameters. Afterwards, two dynamic closure approximations are discussed, one of them considering the relaxation of the fourth order orientational parameter and leading to a novel expression for the free-energy like function in terms of the scalar order parameter. Considering the evolution equation of the density of the system and values of the interaction parameter for which isotropic and nematic phases coexist, our analysis predicts that patterns and traveling waves can be produced in lyotropic uniaxial nematics even in the absence of external driving.Comment: 34 pages, 7 figure

The generation of student engagement as a cognition-affect-behaviour process in a Twitter learning experience

Twitter is a microblog that allows users to interact about a topic in online discussion. This makes it an interesting interactive tool with possibilities to increase student engagement and learning performance through active collaboration in an informal learning environment. However, few articles take a quantitative approach to investigate the creation of student engagement using this social networking site. To address this gap, we propose a series of activities conducted through Twitter to analyse the engagement generation process in a sample of 110 students in the first year of a business and administration degree at a large Spanish university. The results show that the engagement process is created through active collaborative learning and enjoyment, and that engaged students are more satisfied with the activity and perceive greater learning performance. This leads us to recommend teachers to encourage active and collaborative activities to make students more engaged and satisfied, and improve their performance.es consisting of applying the concepts studied in class to practical environments, and activities where students browse for online information and take part in a debate, are more enjoyable

The impact of a large object with Jupiter in July 2009

On 2009 July 19, we observed a single, large impact on Jupiter at a planetocentric latitude of 55^{\circ}S. This and the Shoemaker-Levy 9 (SL9) impacts on Jupiter in 1994 are the only planetary-scale impacts ever observed. The 2009 impact had an entry trajectory opposite and with a lower incidence angle than that of SL9. Comparison of the initial aerosol cloud debris properties, spanning 4,800 km east-west and 2,500 km north-south, with those produced by the SL9 fragments, and dynamical calculations of pre-impact orbit, indicate that the impactor was most probably an icy body with a size of 0.5-1 km. The collision rate of events of this magnitude may be five to ten times more frequent than previously thought. The search for unpredicted impacts, such as the current one, could be best performed in 890-nm and K (2.03-2.36 {\mu}m) filters in strong gaseous absorption, where the high-altitude aerosols are more reflective than Jupiter's primary cloud.Comment: 15 pages, 5 figure

Symmetry-projected variational approach for ground and excited states of the two-dimensional Hubbard model

We present a symmetry-projected configuration mixing scheme to describe ground and excited states, with well defined quantum numbers, of the two-dimensional Hubbard model with nearestneighbor hopping and periodic boundary conditions. Results for the half-filled 2{\times}4, 4{\times}4, and 6{\times}6 lattices, as well as doped 4 {\times} 4 systems, compare well with available results, both exact and from other state-of-the-art approximations. We report spectral functions and density of states obtained from a well-controlled ansatz for the (Ne {\pm} 1)-electron system. Symmetry projected methods have been widely used for the many-body nuclear physics problem but have received little attention in the solid state community. Given their relatively low (mean-field) computational cost and the high quality of results here reported, we believe that they deserve further scrutiny

The seasonal origins and ages of water provisioning streams and trees in a tropical montane cloud forest

Determining the sources of water provisioning streams, soils, and vegetation can provide important insights into the water that sustains critical ecosystem functions now and how those functions may be expected to respond given projected changes in the global hydrologic cycle. We developed multi-year time series of water isotope ratios (δ18O and δ2H) based on twice-monthly collections of precipitation, lysimeter, and tree branch xylem waters from a seasonally dry tropical montane cloud forest in the southeastern Andes mountains of Peru. We then used this information to determine indices of the seasonal origins, the young water fractions (Fyw), and the new water fractions (Fnew) of soil, stream, and tree water. There was no evidence for intra-annual variation in the seasonal origins of stream water and lysimeter water from 1 m depth, both of which were predominantly comprised of wet-season precipitation even during the dry seasons. However, branch xylem waters demonstrated an intra-annual shift in seasonal origin: xylem waters were comprised of wet-season precipitation during the wet season and dry-season precipitation during the dry season. The young water fractions of lysimeter (&lt; 15 %) and stream (5 %) waters were lower than the young water fraction (37 %) in branch xylem waters. The new water fraction (an indicator of water ≤ 2 weeks old in this study) was estimated to be 12 % for branch xylem waters, while there was no significant evidence for new water in stream or lysimeter waters from 1 m depth. Our results indicate that the source of water for trees in this system varied seasonally, such that recent precipitation may be more immediately taken up by shallow tree roots. In comparison, the source of water for soils and streams did not vary seasonally, such that precipitation may mix and reside in soils and take longer to transit into the stream. Our insights into the seasonal origins and ages of water in soils, streams, and vegetation in this humid tropical montane cloud forest add to understanding of the mechanisms that govern the partitioning of water moving through different ecosystems.</p

Supersymmetric sound in fluids

We consider the hydrodynamics of supersymmetric fluids. Supersymmetry is broken spontaneously and the low energy spectrum includes a fermionic massless mode, the $\mathit{phonino}$. We use two complementary approaches to describe the system: First, we construct a generating functional from which we derive the equations of motion of the fluid and of the phonino propagating through the fluid. We write the form of the leading corrections in the derivative expansion, and show that the so called diffusion terms in the supercurrent are in fact not dissipative. Second, we use an effective field theory approach which utilizes a non-linear realization of supersymmetry to analyze the interactions between phoninos and phonons, and demonstrate the conservation of entropy in ideal fluids. We comment on possible phenomenological consequences for gravitino physics in the early universe.Comment: Modified introduction and discussion of diffusion terms in the supercurren

Challenges while MOOCifying a HE eLearning course on Universal Accessibility

There are some similarities in developing a traditional Higher Education (HE) eLearning course and MOOCs (Massive Open Online Courses), due to the use of the basis of eLearning instructional design. But in MOOCs, students should be continually influenced by information, social interactions and experiences forcing the faculty to come up with new approaches and ideas to develop a really engaging course. In this paper, the process of MOOCifying an online course on Universal Accessibility is detailed. The needed quality model is based upon the one used for all online degree programs at our university and on a variable metric specially designed for UNED MOOC courses making possible to control how each course was structured, what kind of resources were used and how activities, interaction and assessment were included. The learning activities were completely adapted, along with the content itself and the on-line assessment. For this purpose, the Gardner's Multiple Intelligences Product Grid has been selected