Semi-Bogomol'nyi-Prasad-Sommerfield sphaleron and its dynamics.

We construct a simple field theory in which a sphaleron, i.e., a saddle-point particle-like solution, forms a semi-BPS state with a background defect that is an impurity.

Relativistic moduli space and critical velocity in kink collisions.

One important tool in the analysis of the collision of kinks and other topological solitons is the reduction of the original field theory to a finite-dimensional system of so-called collective coordinates. Here we study one recent proposal of a collective coordinate model (CCM), the perturbative relativistic moduli space (pRMS), where the amplitudes of the Derrick modes are promoted to collective coordinates. In particular, we analyze the possibility to calculate within the pRMS the critical velocity, i.

Observing changes in human functioning during induced sleep deficiency and recovery periods.

Prolonged periods of sleep restriction seem to be common in the contemporary world. Sleep loss causes perturbations of circadian rhythmicity and degradation of waking alertness as reflected in attention, cognitive efficiency and memory. Understanding whether and how the human brain recovers from chronic sleep loss is important not only from a scientific but also from a public health perspective.

Collective Coordinate Model of Kink-Antikink Collisions in ϕ^{4} Theory.

The fractal velocity pattern in symmetric kink-antikink collisions in ϕ^{4} theory is shown to emerge from a dynamical model with two effective moduli: the kink-antikink separation and the internal shape mode amplitude. The shape mode usefully approximates Lorentz contractions of the kink and antikink, and the previously problematic null vector in the shape mode amplitude at zero separation is regularized.

Virtual surgical planning and cone beam computed tomography in reconstruction of head and neck tumors - pilot study.

<b>Introduction:</b> The aim of the study was to prove that a combination of visual surgical planning (VSP) and cone beam computed tomography (CBCT) is an optimal technique in fibular free flap reconstructions after complex tumor resections in the head and neck region and that it leads to better functional and aesthetic outcomes. <br><b>Material and method:</b> Six patients (3 females, 3 males) with head and neck tumors were included in the study. The region concerned midface in 2 cases and mandible in 4 patients.