Description: This article discusses bonding and structure of copper nitrenes. Abstract: Copper nitrenes are of interest as intermediates in the catalytic aziridination of olefins and the amination of C-H bonds. However, despite advances in the isolation and study of late-transition-metal multiply bonded complexes, a bona fide structurally characterized example of a terminal copper nitrene has, to our knowledge, not been reported. In anticipation of such a report, terminal copper nitrenes are studied from a computational perspective. The nitrene complexes studied here are of the form (ß-diketiminate)Cu(NPh). Density functional theory (DFT), complete active space self-consistent-field (CASSCF) electronic structure techniques, and hybrid quantum mechanical/molecular mechanical (QM/MM) methods are employed to study such species. While DFT methods indicate that a triplet (S + 1) is the ground state, CASSCF calculations indicate the a singlet (S = 0) is the ground state, with only a small energy gap between the singlet and triplet. Moreover, the ground-state (open-shell) singlet copper nitrene is found to be highly multiconfigurational (i.e., biradical) and to possess a bent geometry about the nitrene nitrogen, contrasting with the linear nitrene geometry of the triplet copper nitrenes. CASSCF calculations also reveal the existence of a closed-shell singlet state with some degree of multiple ...

Description: This article discusses brain, music, and non-Poisson renewal processes. Abstract: In this paper we show that both music composition and brain function, as revealed by the electroencephalogram (EEG) analysis, are renewal non-Poisson processes living in the nonergodic dominion. To reach this important conclusion the authors process the data with the minimum spanning tree method, so as to detect significant events, thereby building a sequence of times, which is the time series to analyze. The the authors show that in both cases, EEG and music composition, these significant events are the signature of a non-Poisson renewal process. This conclusion is reached using a technique of statistical analysis recently developed by the authors' group, the aging experiment (AE). First, the authors find that in both cases the distances between two consecutive events are described by nonexponential histograms, thereby proving the non-Poisson nature of these processes. The corresponding survival probabilities ψ(t) are well fitted by stretched exponentials [ψ(t) ∝ exp (-(yt)a), with 0.5<a<1.] The second step rests on the adoption of AE, which shows that these are renewal processes. The authors show that the stretched exponential, due to its renewal character, is the emerging tip of an iceberg, whose underwater part has slow ...

Description: This article discusses building a Chilean network for long-term socio-ecological research. Abstract: Since their formal inception in 1980, long-term ecological research (LTER) programs have served as a successful organizing framework to create research agendas and funding mechanisms that allow scientists to address meaningful ecological phenomena at the scales they occur. In its 30 years of existence, LTER has expanded its geographic range (currently the International LTER network has more than 40 country members with sites on every continent) and disciplinary foci (principally encompassing the natural and social sciences and leading some to call for a name change to long-term socio-ecological research efforts exist in both Chile and Argentina, and in 2008, the Institute of Ecology and Biodiversity launched Chile's first concerted effort to link three existing sites (Fray Jorge Forest National Park -33° S, Senda Darwin Biological Station - 43° S, and Omora Ethnobotanical Park - 55° S). Here, the authors present a special feature of the Revista Chilena de Historia Natural, dedicated to LTSER, with the aim of 1) providing a synthesis of some of the most emblematic cases of long-term socio-ecological research in Chile; 2) demonstrating the value of these efforts for the integration of research, education and ...

Description: This article discusses C-H functionalization reactivity of a Nickel-Imide. Abstract: We report report bifunctional reactivity of the β-diketiminato Ni(III)-imide [Me₃NN]Ni=NAd (1), which undergoes H-atom abstraction (HAA) reactions with benzylic substrates R-H (indane, ethylbenzene, toluene). Nickel-imide 1 competes with the nickel-amide HAA product [Me₃NN]Ni-NHAd (2) for the resulting hydrocarbyl radical R• to give the nickel-amide [Me₃NN]Ni-N(CHMePh)Ad (3) (R-H = ethylbenzene) or aminoalkyl tautomer [Me₃NN]Ni(ɳ²-CH(Ph)NHAd) (4) (R-H = toluene). A significant amount of functionalized amine R-NHAd is observed in the reaction of 1 with indane along with the dinickel imide {[Me₃NN]Ni}₂(μ-NAd) (5). Kinetic and DFT analyses point to rate-limiting HAA from R-H by 1 to give R•, which may add to either imide 1 or amide 2, each featuring significant N-based radical character. Thus, these studies illustrate a fundamental competition possible in C-H amination systems that proceed via a HAA/radical rebound mechanism.

Description: This article discusses calculating changes in worklife expectancies and lost earnings in personal injury cases. Abstract: This paper utilizes the Bureau of Labor Statistics (BLS) new worklife tables' information on workforce participation probabilities to estimate the effect of an injury on a worker's life expectancy, worklife expectancy and discounted expected income. After a medical opinion has been obtained concerning the effect of an injury on a worker's probabilities of living and remaining active, the BLS's probability figures can be adjusted and incorporated into a Markov process to estimate the impact of the injury. It is shown that Alter and Becker's technique can be adapted to estimate the present value of the lost expected income.