Search results for " symmetry"

Epidemiology of the sarcomas of the jaws in a Peruvian population

2010

Objective: Analysis of the clinical characteristics of patients with Sarcomas of the Jaws treated in the “Instituto Nacional de Enfermedades Neoplasicas. Dr. Eduardo Caceres Graziani” from 1952-2007. Study Design: Review of 155 clinical records of patients with Sarcomas of the Jaws and record of age, gender, size, location, clinical symptoms and signs, histopathological diagnoses and type of treatment. The data obtained were analyzed by means of Student’s statistical t-test, Fisher and Friedman’s test. Results: Analysis of 155 Sarcomas of the Jaws. The average age of patients was 36.8 years old (range: 1-80 years); the female gender was the most frequent (52.9%); the average tumor size was …

Autologous fat transfer to the cranio-maxillofacial region: updates and controversies.

2009

Abstract Background Autologous fat grafts have gained popularity among Cranio-Maxillofacial surgeons within the past years. Most publications report favourable outcomes but lack quantifiable evidence of graft survival. Objectives To assess autologous fat transfer for facial asymmetry, and review the literature focusing on current indications, techniques, complications, fat survival and patient satisfaction. Patients and methods Nine patients presented facial asymmetry due to onchological resection, congenital anomaly, or craniofacial traumatism. A total of 11 autologous fat transfers were performed. Four procedures followed the Coleman technique; in the other seven procedures, fat centrifug…

A comprehensive classification of craniofacial fractures: postmortem and clinical studies with two- and three-dimensional computed tomography.

2002

Abstract A comprehensive classification of midfacial/craniofacial fractures, based on two- and three-dimensional computed tomography (2D and 3D-CT) is presented. We performed a postmortem analysis of 24 patients who had died from trauma with signs of craniofacial fractures, based on 2D and 3D-CT studies with pathoanatomical findings. In addition, CT findings for 100 patients with craniofacial injuries requiring an emergency CT were correlated with surgical findings and follow-up results. On the basis of the analysis of a total of 377 fractures a classification system is proposed. The system is based on the use of the AO/ASIF (Arbeitsgemeinschaft fur Osteosynthesefragen/Association for the S…

Stochastic analysis of the critical velocity of an axially moving cracked elastic plate

2014

In this study, a probabilistic analysis of the critical velocity for an axially moving cracked elastic and isotropic plate is presented. Axially moving materials are commonly used in modelling of manufacturing processes, like paper making and plastic forming. In such systems, the most serious threats to runnability are instability and material fracture, and finding the critical value of velocity is essential for efficiency. In this paper, a formula for the critical velocity is derived under constraints for the probabilities of instability and fracture. The significance of randomness in different model parameters is investigated for parameter ranges typical of paper material and paper machin…

A descendent tropical Landau–Ginzburg potential for $\mathbb{P}^2$

2016

A rigidity theorem for Lagrangian deformations

2005

We consider deformations of singular Lagrangian varieties in symplectic manifolds. We prove that a Lagrangian deformation of a Lagrangian complete intersection is analytically rigid provided that this is the case infinitesimally. This result is given as a consequence of the coherence of the direct image sheaves of relative infinitesimal Lagrangian deformations.

Enumerative Aspects of the Gross-Siebert Program

2015

For the last decade, Mark Gross and Bernd Siebert have worked with a number of collaborators to push forward a program whose aim is an understanding of mirror symmetry. In this chapter, we’ll present certain elements of the “Gross-Siebert” program. We begin by sketching its main themes and goals. Next, we review the basic definitions and results of two main tools of the program, logarithmic and tropical geometry. These tools are then used to give tropical interpretations of certain enumerative invariants. We study in detail the tropical pencil of elliptic curves in a toric del Pezzo surface. We move on to a basic illustration of mirror symmetry, Gross’s tropical construction for \(\mathbb{P…

Optically detected magnetic resonance studied via the blue luminescence of Ti-doped

1998

The UV-excited blue and green luminescence bands of Ti:sapphire are characterized by ODMR. These emission bands are attributed to two centres, which show very similar properties and are created as a result of a charge-transfer transition of an electron from to ions. In both centres, the d electron of and the hole of are strongly coupled and form triplet states. Doublet systems can be ruled out as sources of the blue-green luminescence. The angular dependence of the ODMR can be explained with an appropriate spin Hamiltonian assuming orthorhombic local symmetry. The orientation of the principal axes of the g-tensor and the crystal-field tensor, found for both centres, suggest that the hole is…

Symmetry and models of single-walled TiO2 nanotubes with rectangular morphology

2011

Abstract The formalism of line symmetry groups for one-periodic (1D) nanostructures with rotohelical symmetry has been applied for symmetry analysis of single-walled titania nanotubes (SW TiO2 NTs) formed by rolling up the stoichiometric two-periodic (2D) slabs of anatase structure. Either six- or twelve-layer (101) slabs have been cut from TiO2 crystal in a stable anatase phase. After structural optimization, the latter keeps the centered rectangular symmetry of initial slab slightly compressed along a direction coincided with large sides of elemental rectangles. We have considered two sets of SW TiO2 NTs with optimized six- and twelve-layer structures, which possess chiralities (−n, n) an…

Relativistic simulations of rotational core collapse : I. Methods, initial models, and code tests

2002

We describe an axisymmetric general relativistic code for rotational core collapse. The code evolves the coupled system of metric and fluid equations using the ADM 3+1 formalism and a conformally flat metric approximation of the Einstein equations. The relativistic hydrodynamics equations are formulated as a first-order flux-conservative hyperbolic system and are integrated using high-resolution shock-capturing schemes based on Riemann solvers. We assess the quality of the conformally flat metric approximation for relativistic core collapse and present a comprehensive set of tests which the code successfully passed. The tests include relativistic shock tubes, the preservation of the rotatio…