Demonstration of the stability or instability of multibreathers at low coupling

Whereas there exists a mathematical proof for one-site breathers stability, and an unpublished one for two-site breathers, the methods for determining the stability properties of multibreathers rely on numerical computation of the Floquet multipliers or on the weak nonlinearity approximation leading to discrete nonlinear Schrödinger equations. Here we present a set of multibreather stability theorems (MST) that provides a simple method to determine multibreathers stability in Klein–Gordon systems. These theorems are based in the application of degenerate perturbation theory to Aubry’s band theory. We illustrate them with several examples.European Union under the RTN project, LOCNET, HPRN-CT-1999-0016

Interaction of moving discrete breathers with vacancies

In this paper a Frenkel–Kontorova model with a nonlinear int eraction potential is used to describe a vacancy defect in a crystal. According t o recent numerical results [Cuevas et al . Phys. Lett. A 315, 364 (2003)] the vacancy can migrate when it interacts with a moving breather. We study more thoroughl y the phenomenology caused by the interaction of moving breathers with a single v acancy and also with double vacancies. We show that vacancy mobility is strongly correlated with the existence and stability properties of stationary breather s centered at the particles adjacent to the vacancy, which we will now call vacancy breat hers.Ministerio de Educación y Ciencia, Spain, project FIS2004-0118

Excessive thoracic computed tomographic scanning in sarcoidosis

Background: The clinical value of computed tomographic (CT) scanning of the chest in the initial assessment of sarcoidosis was investigated. Methods: One hundred consecutive patients referred to the sarcoidosis outpatient services of the Mount Sinai Medical Center, New York from 1990 to 1992 with a presumptive diagnosis of sarcoidosis were studied. The diagnosis was subsequently confirmed in all by a positive tissue biopsy sample or the Kveim-Siltzbach test. Clinical and laboratory data of each patient were reviewed. Chest radiographs were classified according to the classical stages of sarcoidosis. Thirty five of the 100 patients had a CT scan of the chest performed before presentation. The CT scans were compared with the presenting clinical data and standard chest radiographs in order to determine if they yielded useful additional information regarding diagnosis or treatment. Results: The chest CT scan revealed no additional clinically relevant information compared with conventional chest radiographs in any of the 35 studies performed. In two patients mediastinal adenopathy was detected by CT scan which was not seen on standard radiographs. Two patients thought to exhibit hilar adenopathy and pulmonary infiltrations by standard radiography had no parenchymal disease on the CT scan. Bilateral parenchymal infiltrates were seen in one patient which were interpreted as unilateral infiltrates by standard radiographs. The variance between conventional radiographs and CT scans in these five patients was not clinically valuable. Conclusions: CT scans of the chest do not add clinically useful information to the standard chest radiographs in the initial assessment of sarcoidosis in patients presenting with the typical standard radiological patterns. CT scanning of the thorax is indicated in patients with proven or suspected sarcoidosis when the standard chest radiographs are normal or not typical of sarcoidosis, when signs or symptoms of upper airway obstruction are present, when the patient has haemoptysis, if there is a suspicion of a complicating second intrathoracic disease, or the patient is a candidate for lung transplantation

Immunohistochemical Expression of Growth Factors in the Follicular Wall of Normal and Cystic Ovaries of Sows

Contents: The expression of growth factors was evaluated immunohistochemically in normal and cystic ovaries of sows. The immunohistochemically stained area (IHCSA) was quantified by image analysis to analyse the expression of these proteins in the follicular wall of secondary, tertiary and cystic follicles. IGF-I immunoreactivity was strong in the granulosa cell layer (GC), moderate in the theca interna (TI) and mild in the theca externa (TE) of the normal follicles. There was severe reduction of the labelling to IGF-I in the GC of the follicular and luteinized cysts. In the normal follicles, the reactivity for IGF-II was very similar to pattern noted in IGF-I. There was reduction of the IHCSAs in the GC of the follicular and luteinized cysts, but the decrease was not significant. The staining of the IGF-II in the TI and TE of the cysts was increased, in comparison with normal follicles. The IHCSAs for VEGF were higher in the GC and TE of the normal follicles in contrast to TI, but this difference was noted only in the tertiary follicle. The VEGF reactivity increased in the GC of the cysts, in relation to normal follicles. The results of the current study show that the formation of ovarian cysts in sows is associated with alterations in the immunohistochemical expression of some growth factors.Fil: Sant'Ana, F. J. F.. Universidade do Brasília; BrasilFil: Reis Junior, J. L.. Universidade do Brasília; BrasilFil: Blume, G. R.. Universidade do Brasília; BrasilFil: Gimeno, Eduardo Juan. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rey, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Ortega, Hugo Hector. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentin

Classical and quantum nonlinear localized excitations in discrete systems

Pre-pint tomado de ArxivDiscrete breathers, or intrinsic localized modes, are spatially localized, time–periodic, nonlinear excitations that can exist and propagate in systems of coupled dynamical units. Recently, some experiments show the sighting of a form of discrete breather that exist at the atomic scale in a magnetic solid. Other observations of breathers refer to systems such as Josephson–junction arrays, photonic crystals and optical-switching waveguide arrays. All these observations underscore their importance in physical phenomena at all scales. The authors review some of their latest theoretical contributions in the field of classical and quantum breathers, with possible applications to these widely different physical systems and to many other such as DNA, proteins, quantum dots, quantum computing, etc

Estrangulado littre hernia

Littre´s hernia is a disease of unknown incidence, it’s clinical suspicion is infrequent given the lack of specificity of the symptoms, therefore it’s diagnosis is made intrasurgicaly. We report the case of a patient that consulted due to acute abdominal pain, irreducible and painful mass in the right inguinal region, who since admission was suspected of having a strangulated hernia. After an emergency surgery the intraoperative finding of perforated Littre hernia was performed. The patient was discharged on the sixth postoperative day in good general conditions.La Hernia de Littré es una patología rara de incidencia desconocida. Su sospecha clínica es infrecuente dada la inespecificidad de la sintomatología con la que debuta, por lo que su diagnóstico suele realizarse intraoperatoriamente. Se presenta el caso de un paciente con cuadro clínico de dolor abdominal agudo, masa no reductible y dolorosa en región inguinoescrotal derecha, a quien desde el ingreso se sospecha que presenta una hernia estrangulada. Tras una intervención quirúrgica de urgencia se realiza hallazgo intraoperatorio de hernia de Littré perforada. El paciente fue dado de alta en su sexto día postoperatorio en buenas condiciones generales. A hérnia de Littre é uma doença de incidência desconhecida, é suspeita clínica é infreqüente, dada a falta de especi­ficidade dos sintomas, portanto, seu diagnóstico é feito intra-cirúrgico. Relatamos o caso de um paciente que consul­tou devido a dor abdominal aguda, massa irredutível e dolorosa na região inguinal direita, que desde a admissão foi suspeita de ter uma hérnia estrangulada. Após uma cirurgia de emergência foi realizado o achado intraoperatório de hérnia de Littre perfurada. A paciente recebeu alta hospitalar no sexto dia pós-operatório em boas condições gerais

Static and moving breathers in a DNA model with competing short–range and long–range dispersive interactions

So far, all the studies on breathers on DNA have considered models with either short–range or long-range interaction. However, none of them have considered both kinds of interactions. When both interactions are taken into account, there appear a great number of phenomena, and some of them are considered here. One of these phenomena consists in that short–range interaction provide the existence of moving breathers, a fact that does not occur when only long–range interactions are taken into account. Other phenomena studied here are the existence, stability and shape of static breathers and the properties of moving breathers.Supported during 2001 by the EU project, LOCNET RTN project, HPRN-CT-1999-0016