Anharmonic properties of double giant dipole resonance

A systematic microscopic study of the anharmonic properties of the double giant dipole resonance (DGDR) has been carried out, for the first time, for nuclei with mass number $A$ spanning the whole mass table. It is concluded that the corrections of the energy centroid of the $J^{\pi} = 0^+$ and $2^+$ components of the DGDR from its harmonic limit are negative, have a value of the order of few hundred keV and follow an $A^{-1}$ dependence.Comment: 4 pages, 2 figure

Semiclassical theory of surface plasmons in spheroidal clusters

A microscopic theory of linear response based on the Vlasov equation is extended to systems having spheroidal equilibrium shape. The solution of the linearized Vlasov equation, which gives a semiclassical version of the random phase approximation, is studied for electrons moving in a deformed equilibrium mean field. The deformed field has been approximated by a cavity of spheroidal shape, both prolate and oblate. Contrary to spherical systems, there is now a coupling among excitations of different multipolarity induced by the interaction among constituents. Explicit calculations are performed for the dipole response of deformed clusters of different size. In all cases studied here the photoabsorption strength for prolate clusters always displays a typical double-peaked structure. For oblate clusters we find that the high--frequency component of the plasmon doublet can get fragmented in the medium size region ($N \sim 250$). This fragmentation is related to the presence of two kinds of three-dimensional electron orbits in oblate cavities. The possible scaling of our semiclassical equations with the valence electron number and density is investigated.Comment: 23 pages, 8 figures, revised version, includes discussion of scalin

An orbital-free molecular dynamics study of melting in K_20, K_55, K_92, K_142, Rb_55 and Cs_55 clusters

The melting-like transition in potasium clusters K_N, with N=20, 55, 92 and 142, is studied by using an orbital-free density-functional constant-energy molecular dynamics simulation method, and compared to previous theoretical results on the melting-like transition in sodium clusters of the same sizes. Melting in potasium and sodium clusters proceeds in a similar way: a surface melting stage develops upon heating before the homogeneous melting temperature is reached. Premelting effects are nevertheless more important and more easily established in potasium clusters, and the transition regions spread over temperature intervals which are wider than in the case of sodium. For all the sizes considered, the percentage melting temperature reduction when passing from Na to K clusters is substantially larger than in the bulk. Once those two materials have been compared for a number of different cluster sizes, we study the melting-like transition in Rb_55 and Cs_55 clusters and make a comparison with the melting behavior of Na_55 and K_55. As the atomic number increases, the height of the specific heat peaks decreases, their width increases, and the melting temperature decreases as in bulk melting, but in a more pronounced way.Comment: LaTeX file. 6 pages with 17 pictures. Final version with minor change

Resource Re-allocation for Data Inter-dependent Continuous Tasks in Grids

Many researchers focus on resource intensive tasks which have to be run continuously over long periods. A Grid may offer resources for these tasks, but they are contested by multiple client agents. Hence, a Grid might be unwilling to allocate its resources for long terms, leading to tasks’ interruptions. This issue becomes more substantial when tasks are data inter-dependent, where one interrupted task may cause an interruption of a bundle of other tasks. In this paper, we discuss a new resource re-allocation strategy for a client, in which resources are re-allocated between the client tasks in order to avoid prolonged interruptions. Those re-allocations are decided by a client agent, but they should be agreed with a Grid and can be performed only by a Grid. Our strategy has been tested within different Grid environments and noticeably improves client utilities in almost all cases

Galvanic oxidation of bimetallic Zn-Fe nanoparticles for oxygen scavenging

Bimetallic nanoparticles (NP) have demonstrated outstanding multifunctional characteristics, which depend on their size, distribution and composition. In this study, we show the possibility of tailoring the oxidation behavior of Zn-Fe bimetallic nanoparticles produced by magnetron sputtering and gas agglomeration system. Zn and Fe metals were coupled to promote faster oxidation of Zn, stimulating a galvanic mechanism due to the dissimilar corrosion potential in the nanoparticles. The results revealed Zn dissolution occurring at high humidity environments for bimetallic Zn-Fe nanoparticles where no intermix exists between Zn and Fe; however, such dissolution is excluded for ZnFe alloys. The effect of the galvanic couple on the Zn dissolution was confirmed by molecular dynamic simulations. This bimetallic system can be exploited as moisture-activated oxygen scavenger materials due to the acceleration in the oxidation mechanism.This research is sponsored by FEDER funds through the program COMPETE – Programa Operacional Factores de Competitividade and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2019, and UID/ EMS/00285/2013 and in the framework of ERA-SIINN/0004/2013, PTDC/CTM-NAN/4242/2014 and PTDC/NAN-MAT/30789/2017 projects, and through IDMEC, under LAETA, project UIDB/50022/2020. This research was supported by Norte Regional Operational Program 2014-2020 (Norte2020) through the European Regional Development Fund (ERDF) Nanotechnology based functional solutions (NORTE-01- 0145-FEDER-000019) and through European Social Fund (FSE), under the National Doctoral Program in “Surfaces Engineering and Protection”, NORTE-08-5369-FSE-000047. The authors would like to acknowledge that this project received funding from the EU Framework Programme for Research and Innovation H2020, scheme COFUND – Cofunding of Regional, National and International Programmes, under Grant Agreement 713640. The authors also thank the financial support by Portuguese Foundation for Science and Technology (FCT) in the framework of the HEALTHYDENT (co-financed via FEDER (PT2020) POCI-01-0145-FEDER-030708 and FCT (PIDDAC)), in the framework of the ATRITO-0 (co-financed via FEDER (PT2020) POCI-01-0145-FEDER030446 and FCT (PIDDAC)) and in the framework of the project NANOXYPACK co-financed via FEDER (PT2020) POCI-01-0145-FEDER030789

Ectopic hbox12 Expression Evoked by Histone Deacetylase Inhibition Disrupts Axial Specification of the Sea Urchin Embryo

Dorsal/ventral patterning of the sea urchin embryo depends upon the establishment of a Nodal-expressing ventral organizer. Recently, we showed that spatial positioning of this organizer relies on the dorsal-specific transcription of the Hbox12 repressor. Building on these findings, we determined the influence of the epigenetic milieu on the expression of hbox12 and nodal genes. We find that Trichostatin-A, a potent and selective histone-deacetylases inhibitor, induces histone hyperacetylation in hbox12 chromatin, evoking broad ectopic expression of the gene. Transcription of nodal concomitantly drops, prejudicing dorsal/ventral polarity of the resulting larvae. Remarkably, impairing hbox12 function, either in a spatially-restricted sector or in the whole embryo, specifically rescues nodal transcription in Trichostatin-A-treated larvae. Beyond strengthen the notion that nodal expression is not allowed in the presence of functional Hbox12 in the same cells, these results highlight a critical role of histone deacetylases in regulating the spatial expression of hbox12

Security lies in obedience - Voices of young women of a slum in Pakistan

<p>Abstract</p> <p>Background</p> <p>Existing literature shows that young people, especially women, have poor knowledge about sexuality and reproductive health. Many of the difficulties young women experience are related to beliefs and expectations in society making them more vulnerable to reproductive ill health. The objective of this study was to explore how young women living in a slum in Islamabad are prepared for marriage and how they understand and perceive their transition to marriage and the start of sexual and childbearing activity.</p> <p>Methods</p> <p>Twenty qualitative interviews and three focus group discussions were conducted with young women residing in a slum of Islamabad. Content analysis was used to explore how the participants represented and explained their situation and how decisions about their marriage were made.</p> <p>Results</p> <p>The main theme identified was <it>security lies in obedience</it>. The two sub-themes contributing to the main theme were <it>socialization into submissiveness </it>and <it>transition into adulthood in silence</it>. The theme and the sub-themes illustrate the situation of young women in a poor setting in Pakistan.</p> <p>Conclusion</p> <p>The study demonstrates how, in a culture of silence around sexuality, young women's socialization into submissiveness lays the foundation for the lack of control over the future reproductive health that they experience.</p