Hidden orders in amorphous structures: extraction of nearest neighbor networks of amorphous Nd-Fe alloys with Gabriel graph analyses

Using the scheme of Delaunay and Gabriel graphs, we analyzed the amorphous structures of computationally created Nd-Fe alloys for several composition ratios based on melt quench simulations with finite temperature first-principles molecular dynamics.By the comparison of the radial distribution functions of the whole system and those derived from the Delaunay and Gabriel graphs, it was shown that the Gabriel graphs represent the first nearest neighbor networks well in the examined amorphous systems. From the Gabriel graph analyses, we examined the coordination structures of amorphous Nd-Fe alloys statistically. We found that the ranges of distributions of coordination numbers vary depending on the composition ratio. The angular distributions among three adjacent atoms were also analyzed, and it was found that the angular distributions behave differently in the Nd-rich and Fe-rich samples. We found that the orders in the amorphous system becomes stronger as increasing the Nd ratio, which corresponds to the appearance of crystalline grain boundary phases at high Nd composition ratio [T. T. Sasaki et al., Acta Mater. 115, 269-277 (2016)].Comment: 9 pages, 9 figure

Caenorhabditis elegans ortholog of the p24/p22 subunit, DNC-3, is essential for the formation of the dynactin complex by bridging DNC-1/p150Glued and DNC-2/dynamitin

Dynactin is a multisubunit protein complex required for the activity of cytoplasmic dynein. In Caenorhabditis elegans, although 10 of the 11 dynactin subunits were identified based on the sequence similarities to their orthologs, the p24/p22 subunit has not been detected in the genome. Here, we demonstrate that DNC-3 (W10G11.20) is the functional counterpart of the p24/p22 subunit in C. elegans. RNAi phenotypes and subcellular localization of DNC-3 in early C. elegans embryos were nearly identical to those of the known dynactin components. All other dynactin subunits were co-immunoprecipitated with DNC-3, indicating that DNC-3 is a core component of dynactin. Furthermore, the overall secondary structure of DNC-3 resembles to those of the mammalian and yeast p24/p22. We found that DNC-3 is required for the localization of the DNC-1/p150Glued and DNC-2/dynamitin, the two components of the projection arm of dynactin, to the nuclear envelope of meiotic nuclei in the adult gonad. Moreover, DNC-3 physically interacted with DNC-1 and DNC-2 and significantly enhanced the binding ability between DNC-1 and DNC-2 in vitro. These results suggest that DNC-3 is essential for the formation of the projection arm subcomplex of dynactin

The Electoral Impact of Direct-Democratic Practices

In recent years there has been a growing interest in the integration of mechanisms of direct citizen participation in the institutional structure of representative democracy, particularly at the local level. This essay examines the electoral impact of mechanisms of direct citizen participation. Although it is often considered that participatory schemes can be a means to achieve electoral success in the hands of politicians seeking re-election, quantitative analyses of 65 Spanish municipalities demonstrate that electoral success is far from being an immediate consequence of direct democratic practices (DDPs). The qualitative analysis of four cases shows that electoral consequences directly attributable to participatory devices depend on their design and on how they fit into the whole political process. Participatory processes that are too rigid and those, especially, that generate expectations that cannot be translated into real policies may end up having a negative effect. On the other hand, DDPs may account for network-building and improved information among citizens that, in turn, may have electoral consequences. DDPs are thus neither a blessing nor a cure "per se" in their electoral effects. Instead, as with representative democracy, their consequences and success will ultimately depend upon their procedural dimension. Copyright (c) 2008 The Authors. Journal Compilation (c) 2008 Joint Editors and Blackwell Publishing Ltd.

Unveiling the origin of the large coercivity in (Nd, Dy)-Fe-B sintered magnets

Abstract Nd-Fe-B-based permanent magnets are widely used for energy conversion applications. However, their usage at elevated temperatures is difficult due to the relatively low coercivity (H c) with respect to the anisotropy field (H A) of the Nd2Fe14B compound, which is typically 0.2H A. In this work, we found that the coercivity of an (Nd0.8Dy0.2)-Fe-B sintered magnet could reach 0.4H A, which was twice as high as the H c/H A of its Dy-free counterpart. Detailed microstructural characterizations, density functional theory and micromagnetic simulations showed that the large value of coercivity, H c = 0.4H A, originated not only from the enhanced H A of the main phase (intrinsic factor) but also from the reduced magnetization of the thin intergranular phase (extrinsic factor). The latter was attributed to the dissolution of 4 at.% Dy in the intergranular phase that anti-ferromagnetically coupled with Fe. The reduction in the magnetization of the intergranular phase resulted in a change in the angular dependence of coercivity from the Kondorsky type for the Dy-free magnet to the Stoner–Wohlfarth-like shape for the Dy-containing magnet, indicating that the typical pinning-controlled coercivity mechanism began to show nucleation features as the magnetization of the intergranular phase was reduced by Dy substitution