A unique equilibrium efficient frontier with fixed-sum outputs in data envelopment analysis

Based on the equilibrium efficient frontier data envelopment analysis (EEFDEA) approach, Fang (J Oper Res Soc 67:412–420, 2015a) developed an equivalent linear programming model to improve and strengthen the EEFDEA approach. Furthermore, Fang (2015a) indicated that his secondary goal approach can achieve a unique equilibrium efficient frontier. However, through a simple counterexample we demonstrate that Fang’s secondary goal approach cannot always achieve uniqueness of the equilibrium efficient frontier. In this paper, we propose an algorithm based on the secondary goal approach to address the problem. The proposed algorithm is proven mathematically to be an effective approach to guaranteeing the uniqueness of the equilibrium efficient frontier.     

Reaction of α-bromocarboxylic acids with hydrazine and dimethylhydrazine

Nucleofilic reaction of a series of α-bromocarboxylic acids with hydrazine and dimethylhydrazine is studied. High reactivity of α-bromocarboxylic acids is revealed and a series of α-hydrazinoarboxylic acids and N-(1-carboxyalkyl)-N,N-dimethylhydrazinium bromides are synthesized.     

Field theory onR×S 3 topology. V:SU 2 gauge theory

A gauge theory on R×S ³ topology is developed. It is a generalization to the previously obtained field theory on R×S ³ topology and in which equations of motion were obtained for a scalar particle, a spin one-half particle, the electromagnetic field of magnetic moments, and a Shrödinger-type equation, as compared to ordinary field equations defined on a Minkowskian manifold. The new gauge field equations are presented and compared to the ordinary Yang-Mills field equations, and the mathematical and physical differences between them are discussed.On leave from Center for Theoretical Physics, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.     

Specific and nonspecific metal ion-nucleotide interactions at aqueous/solid interfaces functionalized with adenine, thymine, guanine, and cytosine oligomers

This article reports nonlinear optical measurements that quantify, for the first time directly and without labels, how many Mg(2+) cations are bound to DNA 21-mers covalently linked to fused silica/water interfaces maintained at pH 7 and 10 mM NaCl, and what the thermodynamics are of these interactions. The overall interaction of Mg(2+) with adenine, thymine, guanine, and cytosine is found to involve -10.0 ± 0.3, -11.2 ± 0.3, -14.0 ± 0.4, and -14.9 ± 0.4 kJ/mol, and nonspecific interactions with the phosphate and sugar backbone are found to contribute -21.0 ± 0.6 kJ/mol for each Mg(2+) ion bound. The specific and nonspecific contributions to the interaction energy of Mg(2+) with oligonucleotide single strands is found to be additive, which suggests that within the uncertainty of these surface-specific experiments, the Mg(2+) ions are evenly distributed over the oligomers and not isolated to the most strongly binding nucleobase. The nucleobases adenine and thymine are found to bind only three Mg(2+) ions per 21-mer oligonucleotide, while the bases cytosine and guanine are found to bind eleven Mg(2+) ions per 21-mer oligonucleotide.     

Quantum chemical comparison of vertical,adiabatic, and 0‐0 excitation energies: The PYP and GFP chromophores

A number of benchmark studies investigating the performance of quantum chemical methods for calculating vertical excitation energies are today available in the literature. However, less established is the variation between methods in their estimates of the differences between vertical, adiabatic, and 0‐0 excitation energies. To this end, such excitation energies are here calculated for the bright S₁ states of the anionic chromophores of the photoactive yellow protein (PYP) and the green fluorescent protein (GFP) in the gas phase using configuration interaction singles, complete active space self‐consistent field, coupled‐cluster singles and doubles, and time‐dependent density functional theory methods. Although the estimates of the excitation energies vary by more than 1 eV between the methods, the differences between the different types of excitation energies are found to be relatively method‐insensitive, varying by ～0.1 eV only for these particular chromophores. Specifically, the adiabatic energies are uniformly 0.10–0.17 (PYP) and 0.06–0.17 eV (GFP) lower than the vertical energies, and the 0‐0 energies are similarly 0.09–0.14 (PYP) and 0.07–0.17 eV (GFP) lower than the adiabatic energies. © 2012 Wiley Periodicals, Inc.     

Concentration enrichment of urea at cellulose surfaces: results from molecular dynamics simulations and NMR spectroscopy

A combined solid-state NMR and Molecular Dynamics simulation study of cellulose in urea aqueous solution and in pure water was conducted. It was found that the local concentration of urea is significantly enhanced at the cellulose/solution interface. There, urea molecules interact directly with the cellulose through both hydrogen bonds and favorable dispersion interactions, which seem to be the driving force behind the aggregation. The CP/MAS ¹³C spectra was affected by the presence of urea at high concentrations, most notably the signal at 83.4 ppm, which has previously been assigned to C4 atoms in cellulose chains located at surfaces parallel to the (110) crystallographic plane of the cellulose Iβ crystal. Also dynamic properties of the cellulose surfaces, probed by spin-lattice relaxation time ¹³CT ₁ measurements of C4 atoms, are affected by the addition of urea. Molecular Dynamics simulations reproduce the trends of the T ₁ measurements and lends new support to the assignment of signals from individual surfaces. That urea in solution is interacting directly with cellulose may have implications on our understanding of the mechanisms behind cellulose dissolution in alkali/urea aqueous solutions.     

Setting the stage for new catalytic functions in designed proteins--exploring the imine pathway in the efficient decarboxylation of oxaloacetate by an Arg-Lys site in a four-helix bundle protein scaffold

Fourteen 42-residue polypeptides have been designed to identify reactive sites for the catalysis of the decarboxylation of oxaloacetate, a chemical transformation that proceeds through the formation of an imine intermediate. The sequences fold into helix-loop-helix motifs and dimerize to four-helix bundles. The catalytically active lysine residues were incorporated in several surface exposed positions, but also in positions characterised by hydrophobic properties to reduce their pKa values. The molecular environments of the Lys residues were systematically varied, to find which residues were able to stabilise and bind the imine intermediate in the decarboxylation reaction. A two-residue Arg-Lys site formed the main component of the reactive site of the helix-loop-helix dimer Decarb-K34_R33, which obeyed saturation kinetics in catalysing the reaction with a kcat/KM of 0.59 M-1S-1. The rate constant measured was nearly three orders of magnitude larger than the second-order rate constant of the butylamine-catalysed reaction (0.0011 M-1S-1), and four orders of magnitude larger than the pseudo first-order rate constant of the uncatalyzed reaction (1.3 x 10(-5) s(-1)). The sequence of Decarb-K34_R33 contained only a single lysine residue. It was flanked by an arginine in the preceding position in the sequence. A flanking Arg residue provided more efficient catalysis than a flanking Lys or Gln residue. Arginines in flanking positions in the helix, in positions four residues before or after the Lys in the sequence, are not as important in catalysis as the Arg of the Arg-Lys pair. The effect of pKa on the catalytic efficiency of the Lys residue in the decarboxylation reaction is well known. The identification of the role of the flanking Arg residue in catalysing decarboxylation, its optimal position, and the importance of conformational stability reported here sets the stage for developing a number of catalytic systems that depend on the formation of imine intermediates, but that lead to different reaction products.     

Evaluation of the structure/cross-reactivity relationship of polycyclic aromatic compounds using an enzyme-linked immunosorbent assay kit

A commercially available enzyme-linked immunosorbent assay (ELISA) kit, the PAH soil test, was evaluated with regard to cross-reactivity. Phenanthrene in methanol was used as reference substance. Anthracene, naphthalene and fluorene were chosen as representatives of the 16 US-EPA priority-pollutant polycyclic aromatic hydrocarbons (PAHs). In addition, a number of polycyclic aromatic compounds (PACs), including methyl-, phenyl-, and carbonyl-PAHs, as well as NSO-heterocyclic PACs, found at former industrial sites, were chosen for elucidation of structure/cross-reactivity relationships. The study emphasizes the importance of a priori knowledge of sample composition for accurate interpretation of test results.     

Green efficiency performance analysis of the logistics industry in China: based on a kind of machine learning methods

This paper aims to analyze the green efficiency performance of the logistics industry in China’s 30 provinces from 2008 to 2017. We first evaluate the green efficiency of the logistics industry through the non-directional distance function method. Then, we use the functional clustering method funHDDC, which is one of the popular machine learning methods, to divide 30 provinces into 4 clusters and analyze the similarities and differences in green efficiency performance patterns among different groups. Further, we explore the driving factors of dynamic changes in green efficiency through the decomposition method. The main conclusions of this paper are as follows: (1) in general, the level of green efficiency is closely related to the geographical location. From the clustering results, we can find that most of the eastern regions belong to the cluster with higher green efficiency, while most of the western regions belong to the cluster with lower green efficiency. However, the green efficiency performance in several regions with high economic levels, such as Beijing and Shanghai, is not satisfactory. (2) Based on the analysis of decomposition results, the innovation effect of China’s logistics industry is the most obvious, but the efficiency change still needs to be improved, and technical leadership should be strengthened. Based on these conclusions, we further propose some policy recommendations for the green development of the logistics industry in China.

     

The collapse of quantum states: A new interpretation

The collapse of quantum states is analyzed in terms of a breakdown into two generic phases: Phase I, in which the field of potentialities that the quantum state represents undergoes a discontinuous and unpredictable change into one of the base states which corresponds to the measurement performed, and phase II, in which a transition from the level of potentialities to the level of actualities takes place. Phase I is discussed in relation to a comment about collapse, made by Dirac in conversation with the author, Nature makes a choice. An analysis of phase II leads to the suggestion that it occurs only through and as an act of experience. This postulate is shown to elucidate basic questions regarding the interpretation of quantum mechanics, such as the elusive demarcation line between the classical and quantum domains, and the controversy of the ontological vs. epistemological interpretation of quantum mechanics.This work was supported in part by the Colgate Research Council.