Crystal structures of four complexes produced by reaction of copper(I) cyanide with imidazoles

Four complexes of CuCN with imidazoles have been prepared by adding the ligand to a solution of CuCN in aqueous sodium thiosulfate. The imidazole ligands used were 2-methylimidazole (mim), 1,2-dimethylimidazole (dmim), 5-chloro-1-methylimidazole (clmim), and 2-phenylimidazole (phim). Complex 1, (CuCN)(mim) is monoclinic, C2/c, a = 9.565(3), b = 7.764(5), c = 8.983(8) Å, = 96.76(3)°, Z, = 4, Complex 2, (CuCN)(dmim) is monoclinic, P2₁/c, a = 8.120(2), b = 11.796(4), c = 16.375(9) Å, , = 100.87(4)°, Z = 8. Complex 3, (CuCN) (clmim) is monoclinic, C2/c, a = 24.907(4), b = 6.894(5), c = 18.259(4) Å, = 102.79(2)°, Z = 16. Complex 4, (CuCN)(phim) is orthorhombic, Pca2₁, a = 9.204(4), b = 8.125(2), c = 26.304(6) Å, Z, = 8. Complexes 1, 2, and 4 have one-dimensional chains –Cu–CN–Cu– with an imidazole bonded to each Cu. Complex 3 has a two-dimensional sheet of CuCN, again with an imidazole bonded to each Cu. In 1 the imidazole group is disordered by a two-fold rotation approximately around the N···N direction in the imidazole group. In 3 one of the imidazole groups has a disorder involving exchange of the Cl and CH₃.     

Structural disorder, octahedral coordination and two-dimensional ferromagnetism in anhydrous alums

The crystal structures of the triangular lattice, layered anhydrous alums KCr(SO₄)₂, RbCr(SO₄)₂ and KAl(SO₄)₂ are characterized by X-ray and neutron powder diffraction (NPD) at temperatures between 1.4 and 773 K. The compounds all crystallize in the space group , with octahedral coordination of the trivalent cations. In all cases, small amounts of disorder in the stacking of the triangular layers of corner sharing MO₆ octahedra and SO₄ tetrahedra is seen, with the MO₆−SO₄ network rotated in opposite directions between layers. The electron diffraction study of KCr(SO₄)₂ supports this model, which on an average can be taken to imply trigonal prismatic coordination for the M³⁺ ions; as was previously reported for the prototype anhydrous alum, KAl(SO₄)₂. The temperature-dependent magnetic susceptibilities for ACr(SO₄)₂ (A=K, Rb, Cs) indicate the presence of predominantly ferromagnetic interactions. Low-temperature powder neutron diffraction reveals that the magnetic ordering is ferromagnetic in-plane, with antiferromagnetic ordering between planes below 3 K.     

Heart rate variability analysis by chaotic global techniques in children with attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is characterized by decreased attention span, impulsiveness, and hyperactivity. Autonomic nervous system imbalance was previously described in this population. We aim to compare the autonomic function of children with ADHD and controls by analyzing heart rate variability (HRV). Children with ADHD (22 boys, mean age 9.964 years) and 28 controls (15 boys, mean age 9.857 years) rested in supine position with spontaneous breathing for 20 min. Heart rate was recorded beat by beat. HRV analysis was performed by use of chaotic global techniques. ADHD promoted an increase in the chaotic forward parameter. The algorithm which applied all three chaotic global parameters was only the second optimum statistically measured by Kruskal–Wallis (P < 0.0001) and low standard deviations. It was also highly influential by principal component analysis with almost all variation covered by the first two components. The third algorithm which lacked the (high spectral Detrended Fluctuation Analysis) parameter performed best statistically. However, we chose the algorithm which applied all three chaotic globals due to previous studies mentioned in the text—forward and inverse problems. Comparison of the autonomic function by analyzing HRV with chaotic global techniques suggests an increase in chaotic activity in children with ADHD in relation to the control group. © 2015 Wiley Periodicals, Inc. Complexity 21: 412–419, 2016     

Fermionic Ising glasses with BCS pairing interaction. Tricritical behaviour

We have examined the role of the BCS pairing mechanism in the formation of the magnetic moment and henceforth a spin glass (SG) phase by studying a fermionic Sherrington-Kirkpatrick model with a local BCS coupling between the fermions. This model is obtained by using perturbation theory to trace out the conduction electrons degrees of freedom in conventional superconducting alloys. The model is formulated in the path integral formalism where the spin operators are represented by bilinear combinations of Grassmann fields and it reduces to a single site problem that can be solved within the static approximation with a replica symmetric ansatz. We argue that this is a valid procedure for values of temperature above the de Almeida-Thouless instability line. The phase diagram in the T-g plane, where g is the strength of the pairing interaction, for fixed variance J ² /N of the random couplings J_ij, exhibits three regions: a normal paramagnetic (NP) phase, a spin glass (SG) phase and a pairing (PAIR) phase where there is formation of local pairs.The NP and PAIR phases are separated by a second order transition line g=g _c (T) that ends at a tricritical point T ₃ =0.9807J, g ₃ =5,8843J, from where it becomes a first order transition line that meets the line of second order transitions at T _c =0.9570J that separates the NP and the SG phases. For T<T _c the SG phase is separated from the PAIR phase by a line of first order transitions. These results agree qualitatively with experimental data in . Received 14 May 1998     

Correlation Functions by Cluster Variation Method for Ising Model with NN, NNN, and Plaquette Interactions

We consider a procedure for calculating the pair correlation function in the context of cluster variation methods (CVM). As specific cases, we study the pair correlation function in the paramagnetic phase of the Ising model with nearest neighbors, next to nearest neighbors, and plaquette interactions in two and three dimensions. In presence of competing interactions, the so-called disorder line separates in the paramagnetic phase a region where the correlation function has the usual exponential behavior from a region where the correlation has an oscillating, exponentially damped behavior. In two dimensions, using the plaquette as the maximal cluster of the CVM approximation, we calculate the phase diagram and the disorder line for a case where a comparison is possible with known results for the eight-vertex model. In three dimensions, in the CVM cube approximation, we calculate the phase diagram and the disorder line in some cases of particular interest. The relevance of our results for experimental systems like mixtures of oil, water, and surfactant is also discussed.     

Paradoxical vocal fold motion: Presentation and treatment options

Paradoxical vocal fold motion is a rare disorder in which adduction of the folds occurs on inspiration. The disorder presents with signs of airway obstruction and often airway distress, so proper diagnosis by the otorhinolaryngologist is critical to subsequent management. We present a retrospective review of 10 patients with the diagnosis of paradoxical vocal fold motion seen over a 6-year period. Eight patients were females, and 6 required an acute airway intervention at presentation; 3 patients eventually underwent tracheotomy for respiratory decompensation. Six patients had a prior diagnosis of asthma, and this was determined to contribute to their respiratory status. Five patients were treated with botulinum toxin and 2 with flexible nasolaryngoscopic biofeedback, which improved the outcome. A review of the literature confirms a female predominance of patients presenting with paradoxical adduction and airway distress, often with a history of asthma and psychopathology. Our experience with botulinum toxin and biofeedback suggests that these procedures are viable treatment options in the management of patients with this disorder.     

Replica Symmetry Breaking in Short-Range Spin Glasses: Theoretical Foundations and Numerical Evidences

We discuss replica symmetry breaking (RSB) in spin glasses. We update work in this area, from both the analytical and numerical points of view. We give particular attention to the difficulties stressed by Newman and Stein concerning the problem of constructing pure states in spin glass systems. We mainly discuss what happens in finite-dimensional, realistic spin glasses. Together with a detailed review of some of the most important features, facts, data, and phenomena, we present some new theoretical ideas and numerical results. We discuss among others the basic idea of the RSB theory, correlation functions, interfaces, overlaps, pure states, random field, and the dynamical approach. We present new numerical results for the behaviors of coupled replicas and about the numerical verification of sum rules, and we review some of the available numerical results that we consider of larger importance (for example, the determination of the phase transition point, the correlation functions, the window overlaps, and the dynamical behavior of the system).     

Order–Disorder Transitions in Model Liquids of Mesogenic Trimers

Monte Carlo simulations have been performed for realistically dense liquids of model trimers consisting of rigid cores connected by virtual bonds representing semiflexible spacers. The conformational characteristics of the trimers are approximately regulated in two cases to mimic (CH₂)_n spacers with n odd or even. All simulated systems undergo reversible isotropic–nematic phase transitions at well defined temperatures, showing odd–even oscillations in good agreement with experiments. The transitions are coupled with a conformational selection favoring extended conformations in the nematic liquids. The odd–even oscillations and the conformational distribution in the nematic liquids are fully explained on the basis of the intrinsic conformational characteristics of the model trimers.     

Many-Body Localization and the Emergence of Quantum Darwinism

Quantum Darwinism (QD) is the process responsible for the proliferation of redundant information in the environment of a quantum system that is being decohered. This enables independent observers to access separate environmental fragments and reach consensus about the system’s state. In this work, we study the effect of disorder in the emergence of QD and find that a highly disordered environment is greatly beneficial for it. By introducing the notion of lack of redundancy to quantify objectivity, we show that it behaves analogously to the entanglement entropy (EE) of the environmental eigenstate taken as an initial state. This allows us to estimate the many-body mobility edge by means of our Darwinistic measure, implicating the existence of a critical degree of disorder beyond which the degree of objectivity rises the larger the environment is. The latter hints the key role that disorder may play when the environment is of a thermodynamic size. At last, we show that a highly disordered evolution may reduce the spoiling of redundancy in the presence of intra-environment interactions.     

Statistical Analysis of Disordered Polytype Structures Observed by HREM Method

A statistical analysis of cp-layer distribution in ZnS:Al crystal was carried out. It was based on examinations of crystal structure by HREM (High Resolution Electron Microscopy). The analysis was carried out to compare the observed structures and structures expected from the Superlattice Model of Polytype Structure Formation (SMP). This comparison occurs acceptable to the Model.