Observation of correlations up to the micrometer scale in sliding charge-density waves

High-resolution coherent x-ray diffraction experiment has been performed on the charge density wave (CDW) system K$_{0.3}$MoO$_3$. The $2k_F$ satellite reflection associated with the CDW has been measured with respect to external dc currents. In the sliding regime, the $2k_F$ satellite reflection displays secondary satellites along the chain axis which corresponds to correlations up to the micrometer scale. This super long range order is 1500 times larger than the CDW period itself. This new type of electronic correlation seems inherent to the collective dynamics of electrons in charge density wave systems. Several scenarios are discussed.Comment: 4 pages, 3 figures Typos added, references remove

Spatial Characterization of Fraunhofer Diffraction in a Four-Level Light-Matter Coupling System

We explore the spatial features of various orders of Fraunhofer diffraction patterns in a four-level N-type atomic system. The system interacts with a weak probe light, a standing wave (SW) coupling field in the x-direction, and a cylindrical beam of composite optical vortex type. We derive the first-order linear and third-order cross-Kerr nonlinear parts of the probe susceptibility by expanding the probe susceptibility of the system into the second order of the SW beam. This allows us to solve the integral equation of Fraunhofer diffraction, decoding its varying degrees to specific degrees of Bessel functions containing the nonlinear susceptibility. Notably, the nonlinear susceptibility exhibits dependence on the Orbital Angular Momentum (OAM) of the light beam, leading to spatial variations in the Bessel functions and, consequently, in the different orders of Fraunhofer diffraction. Leveraging the manipulation of OAM, we achieve precise control over the spatial mapping of diverse diffraction orders at various locations. Our research sheds new light on the spatial behavior of Fraunhofer diffraction in complex atomic systems. It presents exciting prospects for harnessing the OAM characteristics of light in future optical technologies

Cultural brokering with Syrian refugee families with young children: an exploration of challenges and best practices in psychosocial adaptation

This study examined the challenges and critical psychosocial needs of Syrian refugee families with young children in Western Canada, and the role of cultural brokering in facilitating their psychosocial adaptation. Using a community-based participatory research approach and critical incident method, the study involved nine Arabic-speaking cultural brokers who were working with Syrian refugee families using holistic supports during early resettlement. Data collected through focus groups and semi-structured interviews are presented in five illustrative case studies, and reveal that Syrian families struggled with feeling safe and secure in Canada, adjusting to the changing roles in the family, and trying to find meaning in their lives. These struggles were attributed to families’ overall challenges navigating various domains of integration (i.e., health, social services, and education), resulting in a heavy reliance on cultural brokers for social linking and bonding activities (Ager & Strang, 2008), including connecting families to needed supports and helping family members build relationships with one another. Challenges faced by families mapped onto the five psychosocial needs of Silove’s (2013) Adaptation after Persecution and Trauma (ADAPT) conceptual framework as well as most of the core domains of Ager and Strang’s (2008) Social Integration framework. This study provides evidence for the use of both of these frameworks in further studies involving Syrian refugee populations; they proved useful for understanding how families can develop necessary skills to engage on their own in linking activities with various Canadian institutions and bridging activities with communities at large

PECULIARITIES OF THE EPIDEMIC PROCESS OF EPIDEMIC PAROTITIS UNDER THE CONDITIONS OF MASS IMMUNOPROPHYLAXIS

Some specific features of the mumps epidemic process under the conditions of mass immunoprevention were analyzed. Incidence rates were higher when there was a remoteness of the primary immunization by live parotitis vaccine. Certain opportunities for amending the epidemic control with this vaccine to avoid infection were emphasized

Wigner crystallization in a polarizable medium

We present a variational study of the 2D and 3D Wigner crystal phase of large polarons. The method generalizes that introduced by S. Fratini,P.\ Qu{\'{e}}merais [Mod. Phys. Lett. B {\bf 12} 1003 (1998)]. We take into account the Wigner crystal normal modes rather than a single mean frequency in the minimization procedure of the variational free energy. We calculate the renormalized modes of the crystal as well as the charge polarization correlation function and polaron radius. The solid phase boundaries are determined via a Lindemann criterion, suitably generalized to take into account the classical-to-quantum cross-over. In the weak electron-phonon coupling limit, the Wigner crystal parameters are renormalized by the electron-phonon interaction leading to a stabilization of the solid phase for low polarizability of the medium. Conversely, at intermediate and strong coupling, the behavior of the system depends strongly on the polarizability of the medium. For weakly polarizable media, a density crossover occurs inside the solid phase when the renormalized plasma frequency approaches the phonon frequency. At low density, we have a renormalized polaron Wigner crystal, while at higher densities the electron-phonon interaction is weakened irrespective of the {\it bare} electron-phonon coupling. For strongly polarizable media, the system behaves as a Lorentz lattice of dipoles. The abrupt softening of the internal polaronic frequency predicted by Fratini and Quemerais is observed near the actual melting point only at very strong coupling, leading to a possible liquid polaronic phase for a wider range of parameters.Comment: 24 pages, 13 figures v1.

Probing Spin-Charge Relation by Magnetoconductance in One-Dimensional Polymer Nanofibers

Polymer nanofibers are one-dimensional organic hydrocarbon systems containing conducting polymers where the non-linear local excitations such as solitons, polarons and bipolarons formed by the electron-phonon interaction were predicted. Magnetoconductance (MC) can simultaneously probe both the spin and charge of these mobile species and identify the effects of electron-electron interactions on these nonlinear excitations. Here we report our observations of a qualitatively different MC in polyacetylene (PA) and in polyaniline (PANI) and polythiophene (PT) nanofibers. In PA the MC is essentially zero, but it is present in PANI and PT. The universal scaling behavior and the zero (finite) MC in PA (PANI and PT) nanofibers provide evidence of Coulomb interactions between spinless charged solitons (interacting polarons which carry both spin and charge)

Large scale numerical investigation of excited states in poly(phenylene)

A density matrix renormalisation group scheme is developed, allowing for the first time essentially exact numerical solutions for the important excited states of a realistic semi-empirical model for oligo-phenylenes. By monitoring the evolution of the energies with chain length and comparing them to the experimental absorption peaks of oligomers and thin films, we assign the four characteristic absorption peaks of phenyl-based polymers. We also determine the position and nature of the nonlinear optical states in this model.Comment: RevTeX, 10 pages, 4 eps figures included using eps

Reconstructing Generalized Logical Networks of Transcriptional Regulation in Mouse Brain from Temporal Gene Expression Data

Gene expression time course data can be used not only to detect differentially expressed genes but also to find temporal associations among genes. The problem of reconstructing generalized logical networks to account for temporal dependencies among genes and environmental stimuli from transcriptomic data is addressed. A network reconstruction algorithm was developed that uses statistical significance as a criterion for network selection to avoid false-positive interactions arising from pure chance. The multinomial hypothesis testing-based network reconstruction allows for explicit specification of the false-positive rate, unique from all extant network inference algorithms. The method is superior to dynamic Bayesian network modeling in a simulation study. Temporal gene expression data from the brains of alcohol-treated mice in an analysis of the molecular response to alcohol are used for modeling. Genes from major neuronal pathways are identified as putative components of the alcohol response mechanism. Nine of these genes have associations with alcohol reported in literature. Several other potentially relevant genes, compatible with independent results from literature mining, may play a role in the response to alcohol. Additional, previously unknown gene interactions were discovered that, subject to biological verification, may offer new clues in the search for the elusive molecular mechanisms of alcoholism

Red blood cell membrane conductance in hereditary haemolytic anaemias

Congenital haemolytic anaemias are inherited disorders caused by red blood cell membrane and cytoskeletal protein defects, deviant hemoglobin synthesis and metabolic enzyme deficiencies. In many cases, although the causing mutation might be known, the pathophysiology and the connection between the particular mutation and the symptoms of the disease are not completely understood. Thus effective treatment is lagging behind. As in many cases abnormal red blood cell cation content and cation leaks go along with the disease, by direct electrophysiological measurements of the general conductance of red blood cells, we aimed to assess if changes in the membrane conductance could be a possible cause. We recorded whole-cell currents from 29 patients with different types of congenital haemolytic anaemias: 14 with hereditary spherocytosis due to mutations in α-spectrin, β-spectrin, ankyrin and band 3 protein; 6 patients with hereditary xerocytosis due to mutations in Piezo1; 6 patients with enzymatic disorders (3 patients with glucose-6-phosphate dehydrogenase deficiency, 1 patient with pyruvate kinase deficiency, 1 patient with glutamate-cysteine ligase deficiency and 1 patient with glutathione reductase deficiency), 1 patient with β-thalassemia and 2 patients, carriers of several mutations and a complex genotype. While the patients with β-thalassemia and metabolic enzyme deficiencies showed no changes in their membrane conductance, the patients with hereditary spherocytosis and hereditary xerocytosis showed largely variable results depending on the underlying mutation