Description: This article discusses a comparison of density functional theory with single- and multireference correlation consistent composite approaches. Abstract: The kinetics and thermodynamics of copper-mediated nitrene insertion into C-H and H-H bonds (the former of methane) have been studied using several levels of theory: B3LYP/6-311++G(d,p), B97-1/cc-pVTZ, PBE1KCIS/cc-pVTZ, and ccCA (correlation consistent Composite Approach). The results show no significant difference among the DFT methods. All three DFT methods predict the ground state of the copper-nitrene model complex, L'Cu(NH), to be a triplet, while single reference ccCA predicts the singlet to be the ground state. The contributions to the total ccCA energy indicate that the singlet state is favored at the MP2/CBS level of theory, while electron correlation beyond this level (CCSD(T)) favors a triplet state, resulting in a close energetic balance between the two states. A multireference ccCA method is applied to the nitrene active species and supports the assignment of a singlet ground state. In general, the largest difference in the model reaction cycles between DFT and ccCA methods is for processes involving radicals and bond dissociation.

Description: This article discusses the activation of water on the TiO2 (110) surface. Abstract: Using first-principles calculations the authors have studied the reactions of water over Ti adatoms on the (110) surface of rutile TiO2. The authors' results provide fundamental insights into the microscopic mechanisms that drive this reaction at the atomic level and assess the possibility of using this system to activate the water dissociation reaction. In particular, the authors show that a single water molecule dissociates exothermically with a small energy barrier of 0.17 eV. After dissociation, both H⁺ and OH⁻ ions bind strongly to the Ti adatom, which serves as an effective reactive center on the TiO2 surface. Finally, clustering of Ti adatoms does not improve the redox activity of the system and results in a slightly higher energy barrier for water dissociation.

Description: This article discusses aging rejuvenation with fractional derivatives. Abstract: We discuss a dynamic procedure that makes a fractional derivatives emerge in the time asymptotic limit of non-Poisson processes. We find that two-state fluctuations, with an inverse power-law distribution of waiting times, finite first moment, and divergent second moment, namely, with the power index μ in the interval 2<μ<3, yield a generalized master equation equivalent to the sum of an ordinary Markov contribution and a fractional derivative term. We show that the order of the fractional derivative depends on the age of the process under study. If the system is infinitely old, the order of the fractional derivative, o, is given by o=3-μ. A brand new system is characterized by the degree o=μ-2. If the system is prepared at time -tₐ<0 and the observation begins at time t=0, we derive the following scenario. For times 0<t«tₐ the system is satisfactorily described by the fractional derivative with o=3-μ. Upon time increase the system undergoes a rejuvenation process that in the time limit t⪢tₐ yields o=μ-2. The intermediate time regime is probably incompatible with a picture based on fractional derivatives, or, at least, with a mono-order fractional derivative.

Description: This poster discusses an analysis of how business students engage in learning in an introductory data analysis course. A variety of pedagogical activities are used in this introductory data analysis course for business students. In fall of 2012, students were able to score points on each of the following activities: experiential group projects, clicker questions, learning modules, online post chapter quizzes, in class exams, and extra credit questions. An analysis was performed to determine how these activities relate to each other and to improvement in student grades.

Description: This article discusses the annual variation of abundance and composition in forest bird assemblages on Navarino Island, Cape Horn Biosphere Reserve, Chile. Abstract: The structure and dynamics of avian communities in the temperate forests of southern South America have been generally studied during the breeding season (November - March), and reports about seasonal variations and migratory behavior of species are almost lacking. This study examined intra-annual variations on a monthly basis in bird species composition and abundance in the world's southernmost forested ecosystems, found in the Cape Horn Biosphere Reserve, Chile (55°S). Combining data obtained through point-count surveys, mist-netting, and checklist methods, the authors recorded a total of 34 bird species belonging to 20 families. Eighteen of these species were Passeriformes, and the most abundant year-round resident species were Thorn-tailed Rayadito (Aphrastura spinicauda) and Patagonian Sierra-Finch (Phrygilus patagonicus). The most abundant seasonal migrants species were White-crested Elaenia (Elaenia albiceps) and Southern House Wren (Troglodytes musculus). Point-count and mist-netting methods showed a reduction in species richness and abundance during winter, with one third of the bird assemblage absent. This proportion was lower than that documented for more northern Nothofagus forests. Additionally, the authors' data provided no evidence that intra-annual patterns of ...