211 research outputs found

    Domain wall dynamics in a two-component Bose-Mott insulator

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    We model the dynamics of two species of bosonic atoms trapped in an optical lattice within the Mott regime by mapping the system onto a spin model. A field gradient breaks the cloud into two domains. We study how the domain wall evolves under adiabatic and diabatic changes of this gradient. We determine the timescales for adiabaticity, and study how temperature evolves for slow ramps. We show that after large, sudden changes of the field gradient, the system does not equilibrate on typical experimental timescales. We find interesting spin dynamics even when the initial temperature is large compared to the super-exchange energy. We discuss the implication of our results for experiments wishing to use such a two-component system for thermometry, or as part of a cooling scheme.Comment: 6 pages, 5 figures Minor typographical errors corrected. Figure labels changed. Added concluding statement

    Anomalous supersolidity in a weakly interacting dipolar Bose mixture on a square lattice

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    We calculate the mean-field phase diagram of a zero-temperature, binary Bose mixture on a square optical lattice, where one species possesses a non-negligible dipole moment. Remarkably, this system exhibits supersolidity for anomalously weak dipolar interaction strengths, which are readily accessible with current experimental capabilities. The supersolid phases are robust, in that they occupy large regions in the parameter space. Further, we identify a first-order quantum phase transition between supersolid and superfluid phases. Our results demonstrate the rich features of the dipolar Bose mixture, and suggest that this system is well suited for exploring supersolidity in the experimental setting

    Functional, physical and psychosocial impact of Temporomandibular Disorders in adolescents and young adults

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    This community-based study investigated the functional, physical and psychosocial impact of Temporomandibular Disorders (TMDs) in adolescents and young adults. It also determined the discriminative capacity of a TMDs-specific oral health related quality of life (OHRQoL) instrument and compared three formats of appraising OHRQoL data. Subjects were recruited from a local Polytechnic. The presence of TMDs was established with the Fonseca Anamnestic Index (FAI), whilst TMDs-specific OHRQoL was evaluated with the Oral Health Impact Profile?TMDs (OHIP-TMDs). Demographic information, FAI and OHIP-TMDs responses were gathered with an on-line questionnaire. Data was analysed using Mann-Whitney U-test, chi-square test and Spearman?s rho correlation with significance level set at 0.05. Data from a total of 244 participants were compiled and examined. The ?no TMDs? (NT) group consisted of 140 subjects (119 females; 21 males) with a mean age of 20.41±3.29 years, while the ?with TMDs? (WT) group composed of 104 subjects (88 females; 16 males) aged 19.82±3.04 years. Significant differences in median severity scores were observed between subjects with and without TMDs for all OHIP-TMDs domains and total OHIP (p values < 0.001). For appraisal of extent and prevalence, significant differences were again observed (p values < 0.05) with the exception of the functional limitation and handicap domains. TMDs impacted physical and psychosocial well-being of adolescents and young adults. OHIP-TMDs, preferably appraised by severity, extent and prevalence, was able to discriminate between subjects with and without TMDs. It holds promise as a TMDs-specific OHRQoL instrument for epidemiological studies

    Real-space mean-field theory of a spin-1 Bose gas in synthetic dimensions

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    The internal degrees of freedom provided by ultracold atoms give a route for realizing higher dimensional physics in systems with limited spatial dimensions. Non-spatial degrees of freedom in these systems are dubbed synthetic dimensions . This connection is useful from an experimental standpoint but complicated by the fact that interactions alter the condensate ground state. Here we use the Gross-Pitaevskii equation to study ground state properties of a spin-1 Bose gas under the combined influence of an optical lattice, spin-orbit coupling, and interactions at the mean field level. The associated phases depend on the sign of the spin-dependent interaction parameter and the strength of the optical lattice potential. We find charge and spin density wave phases which are directly related to helical spin order in real space and affect the behavior of edge currents in the synthetic dimension. We determine the resulting phase diagram as a function of the spin-orbit coupling and spin-dependent interaction strength, considering both attractive (ferromagnetic) and repulsive (polar) spin-dependent interactions. Our results are applicable to current and future experiments, specifically with 87Rb, 7Li, 41K, and 23Na

    Cardiotoxicity of immune spleen cells treated with specific antigen of antiserum

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    Apparent thinning of human visual cortex during childhood is associated with myelination

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    Human cortex appears to thin during childhood development. However, the underlying microstructural mechanisms are unknown. Using functional magnetic resonance imaging (fMRI), quantitative MRI (qMRI), and diffusion MRI (dMRI) in children and adults, we tested what quantitative changes occur to gray and white matter in ventral temporal cortex (VTC) from childhood to adulthood, and how these changes relate to cortical thinning. T1 relaxation time from qMRI and mean diffusivity (MD) from dMRI provide independent and complementary measurements of microstructural properties of gray and white matter tissue. In face- and character-selective regions in lateral VTC, T1 and MD decreased from age 5 to adulthood in mid and deep cortex, as well as in their adjacent white matter. T1 reduction also occurred longitudinally in children’s brain regions. T1 and MD decreases 1) were consistent with tissue growth related to myelination, which we verified with adult histological myelin stains, and 2) were correlated with apparent cortical thinning. In contrast, in place-selective cortex in medial VTC, we found no development of T1 or MD after age 5, and thickness was related to cortical morphology. These findings suggest that lateral VTC likely becomes more myelinated from childhood to adulthood, affecting the contrast of MR images and, in turn, the apparent gray–white boundary. These findings are important because they suggest that VTC does not thin during childhood but instead gets more myelinated. Our data have broad ramifications for understanding both typical and atypical brain development using advanced in vivo quantitative measurements and clinical conditions implicating myelin
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