Description: This article discusses the reciprocal links between evolutionary-ecological sciences and environmental ethics. Confronted with the current environmental crisis, the academic community faces a conceptual and practical problem of dissociation: Ecologists approach nature with the aim of understanding it, whereas environmental ethicists approach nature asking how we should relate to it, or inhabit it. Ecology looks for the "is" of nature, and environmental ethics seeks an "ought" with respect to nature. How can these still largely disconnected and yet parallel courses be bridged? How can the is of ecologists and the ought of eco-philosophers be interrelat-ed? More basically, how can the links between the cognitive-scientific and the practical-ethical spheres be recovered? In this article, the author illustrates the reciprocal relationships between sciences and environmental ethics by examining the Darwinian theory of evolution and discussing its implications for ecologists and ethicists.

Description: This article discusses dynamic approach to the thermodynamics of superdiffusion. Abstract: We address the problem of relating thermodynamics to mechanics in the case of microscopic dynamics without a finite time scale. The solution is obtained by expressing the Tsallis entropic index q as a function of the Lévy index α, and using dynamic rather than probabilistic arguments.

Description: This article discusses fractional calculus as a macroscopic manifestation of randomness. Abstract: We generalize the method of Van Hove [Physica (Amsterdam) 21, 517 (1955)] so as to deal with the case of nonordinary statistical mechanics, that being phenomena with no time-scale separation. We show that in the case of ordinary statistical mechanics, even if the adoption of the Van Hove method imposes randomness upon Hamiltonian dynamics, the resulting statistical process is described using normal calculus techniques. On the other hand, in the case where there is no time-scale separation, this generalized version of Van Hove's method not only imposes randomness upon the microscopic dynamics, but it also transmits randomness to the macroscopic level. As a result, the correct description of macroscopic dynamics has to be expressed in terms of the fractional calculus.

Description: This article discusses estimating solid-liquid phase change enthalpies and entropies. Abstract: A group additivity method based on molecular structure is described that can be used to estimate solid-liquid total phase change entropy (∆₀ᵀ(fus)S(tpce)) and enthalpy (∆₀ᵀ(fus)H(tpce)) of organic molecules. The estimation of these phase changes is described and numerous examples are provided to guide the user in evaluating these properties for a broad range of organic structures. A total of 1858 compounds were used in deriving the group values and these values are tested on a database of 260 additional compounds. The absolute average and relative errors between experimental and calculated values for these 1858 compounds are 9.9 J-mol⁻¹·K⁻¹ and 3.52 kJ·mol⁻¹, and 0.154 and 0.17 for ∆₀ᵀ(fus)S(tpce) and ∆₀ᵀ(fus)H(tpce), respectively. For the 260 test compounds, standard deviations of ± 13.0 J·mol⁻¹·K⁻¹ (∆₀ᵀ(fus)S(tpce)) and ±4.88 kJ mol⁻¹ (∆₀ᵀ(fus)H(tpce)) between experimental and calculated values were obtained. Estimations are provided for both databases. Fusion enthalpies for some additional compounds not included in the statistics are also included in the tabulation.

Description: This article discusses structural dichotomy in six-coordinate d⁰ complexes. Utilization of the bulky acetylide, ᵗBu₃SiC≡C⁻, enabled the synthesis of several early metal polyacetylides. Addition of NaC≡CH to ᵗBu₃SiBr in dimethyl sulfoxide afforded ᵗBu₃SiC≡CH, which was deprotonated to yield ᵗBu₃SiC≡CLi. Treatment of ZrCl₄, HfCl₄, adn TaCl₅ with varying amounts of ᵗBu₃SiC≡CLi gave {(THF)₂Li(ᵗBu₃SiC≡C)₂}Zr(C≡CSiᵗBu₃)₃(THF) (1; THF = tetrahydrofuran), {Et₂O)Li(ᵗBu₃SiC≡C)₂}Hf(C≡CSiᵗBu₃)₃(OEt₂) (2), {Li(ᵗBu₃SiC≡C)₃}₂M(M = Zr, 6; Hf, 7), and {Li(ᵗBu₃SiC≡C)₃}Ta(C≡CSiᵗBu₃)₃ (3). Metathesis of 3 with KOTf generated KTa(C≡CSiᵗBu₃)₆ (4) and cation sequestration of 4 with crypt 2.2.2 provided [K(crypt 2.2.2)][Ta(C≡CSiᵗBu₃)₆](5). Single-crystal X-ray structural studies determined the structures (core symmetry) of 1 (Oh), 2, (Oh), 3 (D₃), 5 (D₃), 6 (Oh), and 7 (Oh). The D₃h to D₃ twist in 3 and 5 has a steric origin, and the counterion position appears inconsequential. Origins of the structural preferences illustrated by the dichotomous twisted trigonal prismatic and octahedral cores of the d⁰ hexaacetylides 5 and 6 were probed through density functional (ADF) and effective core potential (GAMESS) calculations. The structural difference results from a lessening electronic preference for the trigonal prism-primarily a greater HOMO/LUMO gap-upon moving from Ta to Zr, minor steric factors, and increased interligand repulsions in the dianion (VSEPR).