Cephalometric traits in children and adolescents with and without atypical swallowing : a retrospective study

Aim It has been suggested that atypical swallowing (AS) may negatively influence the skeletal and alveolar development, but its specific effects are still unclear. The aim of this work is to compare the cephalometric characteristics of children and adolescents with and without AS. Materials and methods Study design: Case-control retrospective cross-sectional study. One hundred patients with (AS group) and 100 patients without AS (control group, C) were retrospectively selected. Their cephalometric data before orthodontic treatment were compared using a 3-way ANOVA variance test to detect any differences between groups considering: the type of swallowing (AS vs C); whether or not the second dentition was completed (SDC vs SDNC); and the gender (males-M and females-F). In addition, a Student-t test for unpaired data was carried out to detect differences between M and F within the AS and C groups. Results When compared to the controls, AS patients showed a significantly decreased SNB angle (p<.01), increased ANB and SN^Go. Me angles (p<.0001), increased overjet and lower facial height (p<.01), decreased overbite (p<.0001), and increased proclination of the upper incisors. AS-SDC patients also showed significantly increased alveolar length. Within the AS and C groups, skeletal and alveolar measurements were larger in males, with higher significance in the C group, suggesting a different trend of growth in AS patients. Conclusion AS seems to affect the skeletal growth causing mandibular clockwise rotation, skeletal Class II, open bite and incisor proclination. To compensate for these effects, an increase in alveolar growth together with molar eruption seems to be induced

Actin- and myosin-dependent vesicle loading of presynaptic docking sites prior to exocytosis.

Variance analysis of postsynaptic current amplitudes suggests the presence of distinct docking sites (also called release sites) where vesicles pause before exocytosis. Docked vesicles participate in the readily releasable pool (RRP), but the relation between docking site number and RRP size remains unclear. It is also unclear whether all vesicles of the RRP are equally release competent, and what cellular mechanisms underlie RRP renewal. We address here these questions at single glutamatergic synapses, counting released vesicles using deconvolution. We find a remarkably low variance of cumulative vesicle counts during action potential trains. This, combined with Monte Carlo simulations, indicates that vesicles transit through two successive states before exocytosis, so that the RRP is up to 2-fold higher than the docking site number. The transition to the second state has a very rapid rate constant, and is specifically inhibited by latrunculin B and blebbistatin, suggesting the involvement of actin and myosin

Improved Quantum Hard-Sphere Ground-State Equations of State

The London ground-state energy formula as a function of number density for a system of identical boson hard spheres, corrected for the reduced mass of a pair of particles in a sphere-of-influence picture, and generalized to fermion hard-sphere systems with two and four intrinsic degrees of freedom, has a double-pole at the ultimate \textit{regular} (or periodic, e.g., face-centered-cubic) close-packing density usually associated with a crystalline branch. Improved fluid branches are contructed based upon exact, field-theoretic perturbation-theory low-density expansions for many-boson and many-fermion systems, appropriately extrapolated to intermediate densities, but whose ultimate density is irregular or \textit{random} closest close-packing as suggested in studies of a classical system of hard spheres. Results show substantially improved agreement with the best available Green-function Monte Carlo and diffusion Monte Carlo simulations for bosons, as well as with ladder, variational Fermi hypernetted chain, and so-called L-expansion data for two-component fermions.Comment: 15 pages and 7 figure

Mechanisms driving alteration of the Landau state in the vicinity of a second-order phase transition

The rearrangement of the Fermi surface of a homogeneous Fermi system upon approach to a second-order phase transition is studied at zero temperature. The analysis begins with an investigation of solutions of the equation $\epsilon(p)=\mu$, a condition that ordinarily has the Fermi momentum $p_F$ as a single root. The emergence of a bifurcation point in this equation is found to trigger a qualitative alteration of the Landau state, well before the collapse of the collective degree of freedom that is responsible for the second-order transition. The competition between mechanisms that drive rearrangement of the Landau quasiparticle distribution is explored, taking into account the feedback of the rearrangement on the spectrum of critical fluctuations. It is demonstrated that the transformation of the Landau state to a new ground state may be viewed as a first-order phase transition.Comment: 16 pages, 10 figure

Ground state instability in systems of strongly interacting fermions

We analyze stability of a fermion system with model repulsive pair interaction potential. The possibility for different types of restructuring of the Fermi ground state (at sufficiently great coupling constant) is related to the analytic properties of such potential. In particular, for the screened Coulomb law it is shown that the restructuring cannot be of the Fermi condensation type, known earlier for some exactly solvable models, and instead it belongs to the class of topological transitions (TT). For this model, a phase diagram has been built in the variables "screening parameter - coupling constant" which displays two kinds of TT: a 5/2-kind similar to the known Lifshitz transitions in metals, and a 2-kind characteristic for a uniform strongly interacting system.Comment: The article has 11 pages, in Latex 2e (from Lyx), 3 eps figures or a ps fil

Origen de las arterias testiculares en caninos

Ante las discrepancias existentes entre distintos autores de difundidos textos de anatomía animal, el propósito del trabajo fue investigar eventuales diferencias en el origen de las arterias testiculares del perro. Se emplearon 15 cadáveres de caninos de diferente raza, edad y talla. Tras ser inyectados con pasta de repleción (látex coloreado), se les practicaron las disecciones correspondientes. Los resultados obtenidos indicaron que en el 80% de los casos la arteria testicular derecha se originaba de la aorta abdominal, cranealmente con respecto a la arteria testicular izquierda. En el 20% restante se comprobó que ambas lo hacían a la misma altura. Además de enriquecer los conocimientos anatómicos acerca del patrón de irrigación testicular, el hallazgo es aplicable en las técnicas quirúrgicas que involucren la topografía regional estudiada

Phase diagram of the Heisenberg antiferromagnet with four-spin interactions

We study the quantum phase diagram of the Heisenberg planar antiferromagnet with a subset of four-spin ring exchange interactions, using the recently proposed heirarchical mean-field approach. By identifying relevant degrees of freedom, we are able to use a single variational anzatz to map the entire phase diagram of the model and uncover the nature of its various phases. It is shown that there exists a transition between a N\'eel state and a quantum paramagnetic phase, characterized by broken translational invariance. The non-magnetic phase preserves the lattice rotational symmetry, and has a correlated plaquette nature. Our results also suggest that this phase transition can be properly described within the Landau paradigm.Comment: LaTeX 2e, 7 pages, 8 figure

Literacy practices of primary education children in Andalusia (Spain): a family-based perspective

Primary school children develop literacy practices in various domains and situations in everyday life. This study focused on the analysis of literacy practices of children aged 8–12 years from the perspec- tive of their families. 1,843 families participated in the non-experimental explanatory study. The children in these families speak Spanish as a first language and are schooled in this language. The instrument used was a self-report questionnaire about children’s home-literacy practices. The data obtained were analysed using categorical principal components analysis (CATPCA) and analysis of variance (ANOVA). The results show the complex relationship between literacy practices developed by children in the domains of home and school and the limited development of a literacy-promoting ‘third space’. In conclusion, the families in our study had limited awareness of their role as literacy- promoting agents and thought of literacy learning as restricted to formal or academic spaces