A quantum chemical model for a series of self-assembled nanocages: the origin of stability behind the coordination-driven formation of transition metal complexes up to [M₁₂L₂₄]²⁴⁺

Herein, we present a systematic computational model to study the electronic states and free energies of a self-assembled multi-metal complex series. By combining the previously developed model Hamiltonian approach for transition-metal complexes and the generalized Born model, the thermodynamics, optimized geometries, and electronic states of the [Pd12L24]24+ nanocage are revealed, together with [PdnLm]2n+ complex series. The effective model Hamiltonian is a theoretical method to obtain the d-electron wavefunction and potential energy including interaction energy between the transition-metal and ligands. In the present improvement, the electronic state on each transition-metal center is focused as a building unit and solved under the whole electronic field of the assembling system. We realize a reliable and systematic treatment of multi-transition-metal complexes with different sizes and charges. Consequently, our model could reproduce binding energies of the [PdnLm]2n+ complex series quantitatively as compared to density functional theory (DFT). Regarding free energy, we revealed that the assembling solute becomes unstable due to the electrostatic interaction, and effects of the solvent and counter anions mainly compensated it. Optimized geometries were also analysed. The local square-planar coordination structures around the palladium centres were characterized in the complex series. The relationships between the entire symmetrical geometries and the local coordination structures are also discussed. Finally, electronic structures of the [Pd12L24]24+ nanocage were well characterized as a single-determinant, where only dx2−y2 is unoccupied due to the ligand-field effect. We also found that the solvent polarized the electronic states of the Pd ions, whereas the counter anion suppressed the polarization. The present method realizes size-independent reliable and rapid computations, and therefore can be expected to further application studies on self-assembly dynamics

Introduction to the Supplementary Issue “Progress in African Food Culture Research”

Historically, food cultures in various parts of Africa have been nurtured through the interrelationships among people, crops and the natural environment. However, the study on food in sub-Saharan Africa so far has largely been confined to agriculture and food production; there has been little discussions on consumption patterns or eating cultures. Based on fieldwork in rural villages and literature studies, this supplementary issue focuses on the diverse food choices made by local farmers in sub-Saharan Africa in the context of crop selection and consumption and analyzes indigenous knowledge that informs farmers' choices. Moreover, it considers the relationships among the natural environment, crops and food cultures, and should facilitate future study of food cultures in sub-Saharan Africa and elsewhere

Paulo Freire’s Initial Thoughts on Education

The current paper sought to clarify the character of Paulo Freire’s earliest thoughts about education. Freire wrote an article entitled “Educação e Atualidade Brasileira” to gain an educational history and educational philosophy professor at Recife University in 1959. This article preceded his educational practice in the literacy project at Recife, which began in 1962. In “Educação e Atualidade Brasileira”, Freire treats the important problem of “inexperience of democracy” in Brazil and highlights the role of education in democratization. Freire’s ideas are based on the ontology and empiricism of John Dewey. “Inexperience of democracy” was described in the Brazilian historical context of Portuguese colonization and dependence. Thus, Freire argued that Brazilian education was an important part of making Brazil independent. This means that the goal of education is to create new experiences in which people participate and change the historical and cultural context of the country. In the middle period of his career, Freire incorporated Marx’s dialectical materialism into his own thinking. However, the origins and germination of Freire’s initial thinking are represented in “Educação e Atualidade Brasileira”

On the classification of ruled minimal surfaces in pseudo-Euclidean space

This paper gives, in generic situations, a complete classification of ruled minimal surfaces in pseudo-Euclidean space with arbitrary index. In addition, we discuss the condition for ruled minimal surfaces to exist, and give a counter-example on the problem of Bernstein type

Conscientization in Life Guidance Studies

This study clarifies the treatment and problem of consciousness in Life Guidance Studies to explore the significance of Freire’s conscientization in educational practice. There are three aspects to Freire’s consciousness: i.e., (1) critical awareness towards a subject; (2) acting to change reality by critically recognizing the subject; and (3) a growing ability to transform reality through the dialectical development of critical awareness and transformation of reality. These three aspects increasingly influence each other in how conscientization is treated in the Life Guidance Studies curriculum. The concept of conscientization was also adapted in a book published in 1990. The main issue of conscientization is how teachers direct their students’ ability to know and transform reality; therefore, the students can obtain a perspective that avoids the danger of falling into the idealism and activism of conscientization

VARIATIONAL PROBLEMS FOR INTEGRAL INVARIANTS OF THE SECOND FUNDAMENTAL FORM OF A MAP BETWEEN PSEUDO-RIEMANNIAN MANIFOLDS

We study variational problems for integral invariants, which are defined as integrations of invariant functions of the second fundamental form, of a smooth map between pseudo-Riemannian manifolds. We derive the first variational formulae for integral invariants defined from invariant homogeneous polynomials of degree two. Among these integral invariants, we show that the Euler–Lagrange equation of the Chern–Federer energy functional is reduced to a second order PDE. Then we give some examples of Chern–Federer submanifolds in Riemannian space forms

Cosmological Phase Transitions in Composite Higgs Models

We investigate cosmological phase transitions in various composite Higgs models consisting of four-dimensional asymptotically-free gauge field theories. Each model may lead to a confinement-deconfinement transition and a phase transition associated with the spontaneous breaking of a global symmetry that realizes the Standard Model Higgs field as a pseudo-Nambu-Goldstone boson. Based on the argument of universality, we discuss the order of the phase transition associated with the global symmetry breaking by studying the renormalization group flow of the corresponding linear sigma model at finite temperature, which is calculated by utilizing the $\epsilon$-expansion technique at the one-loop order. Our analysis indicates that some composite Higgs models accommodate phenomenologically interesting first-order phase transitions. We also explore the confinement-deconfinement transition in a UV-completed composite Higgs model based on a $Sp(2N_c)$ gauge theory. It is found that the first-order phase transition is favored when the number of degrees of freedom for the $Sp(2N_c)$ gauge field is much larger than that of matter fields in the fundamental representation of $Sp(2N_c)$. We comment on the gravitational wave signal generated by the confinement-deconfinement transition and its detectability at future observations. Our discussions motivate further studies on phase transitions in composite Higgs models with the use of lattice simulations.Comment: 17 pages, 2 figure

Carbonyl-Iron/Epoxy Composite Magnetic Core for Planar Power Inductor Used in Package-Level Power Grid

Our research objective is to realize the basic technology for a next generation package-level power grid (PLPG) for plural application large scale integrated circuits (LSIs). In this study, a carbonyl-iron powder (CIP)/epoxy composite magnetic core, for large-current power inductor used for the main dc-dc converter in the PLPG, has been fabricated and evaluated. 54 vol.%-CIP/epoxy composite core made by screen-printing had a relative permeability of 7.5 and loss tangent of about 0.03 at 100 MHz. The planar power inductor using composite core was fabricated and evaluated, which had a quasi closed magnetic circuit consisting of low permeability composite core and embedded 35-mu m-thick, two-turn copper spiral coil. The fabricated inductor with a 1-mm-square in size had 5.5 nH inductance, Q-factor of 15 at 100 MHz, and 18 m Omega dc coil resistance. Inductance was constant even when the superimposed dc current increased up to around 5.5 A.ArticleIEEE TRANSACTIONS ON MAGNETICS. 49(7):4172-4175 (2013)journal articl