Protein structure prediction from the complementary science perspective.

A comparative analysis between two problems-apparently unrelated-which are solved in a period of ~400 years, viz., the accurate prediction of both the planetary orbits and the protein structures, leads to inferred conjectures that go far beyond the existence of a common path in their resolution, i.e., observation → pattern recognition → modeling. The preliminary results from this analysis indicate that complementary science, together with a new perspective on protein folding, may help us discover common features that could contribute to a more in-depth understanding of still-unsolved problems such as protein folding.

Periodic complex map germs and foliations

Abstract In this paper we study topological and analytical conditions on the orbits of a germ of diffeomorphism in the complex plane in order to obtain periodicity. In particular, we give a simple proof of a finiteness criteria for groups of analytic diffeomorphisms, stated in Brochero Martínez 2003. As an application, we derive some consequences about the integrability of complex vector fields in dimension three in a neighborhood of a singular point.

Innermost stable circular orbits and epicyclic frequencies around a magnetized neutron star / Órbitas circulares marginalmente estables y frecuencias epicíclicas alrededor de una estrella de neutrones magnetizada / Órbitas circulares marginalmente estáveis e frequencias epicicloidais nas proximidades de uma estrela de neutrons magnetizada

El formalismo de la relatividad general es usado para calcular el radio de la órbita marginalmente estable (ROME), las frecuencias kepleriana, de Lense-Thirring, de precesion y oscilación de los movimientos radiales y verticales, de una partícula de prueba neutra que orbita el plano ecuatorial de una estrella de neutrones magnetizada. El espacio tiempo alrededor de la estrella se modela por medio de la solución seis paramétrica derivada por Pachón et al. (2012). Se concluye que la presencia del campo magnético de la fuente tiene efectos apreciables en las cantidades físicas mencionadas arriba y, por tanto, su inclusión es necesaria si se desea describir con más exactitud los procesos físicos que ocurren en la vecindad de este tipo de estrellas tales como la dinámica de discos de acreción. Los resultados presentados aquí también sugieren que la presencia de campos magnéticos intensos pueden introducir correcciones apreciables en, por ejemplo, las predicciones de la masa de estrellas de neutrones hechas con base en el modelo de precesión relativista.

A full-relativistic approach is used to compute the radius of the innermost stable circular orbit (ISCO), the Keplerian, frame-dragging, precession and oscillation frequencies of the radial and vertical motions of neutral test particles orbiting the equatorial plane of a magnetized neutron star. The space-time around the star is modelled by the six parametric solution derived by Pachón et al. (2012) It is shown that the inclusion of an intense magnetic field, such as the one of a neutron star, have non-negligible effects on the above physical quantities, and therefore, its inclusion is necessary in order to obtain a more accurate and realistic description of physical processes, such as the dynamics of accretion disks, occurring in the neighbourhood of this kind of objects. The results discussed here also suggest that the consideration of strong magnetic fields may introduce non-negligible corrections in, e.g., the relativistic precession model and therefore on the predictions made on the mass of neutron stars.

O formalismo da relatividade geral é usado para calcular o raio da órbita marginalmente estável (ROME), as frequencias keplerianas de Lense Thirring, precessao e oscilaçao de movimentos radiais e verticais, de uma partícula de prova neutra em órbita equatorial de uma estrela de neutrón magnetizada. O espaço-tempo ao redor da estrela é modelado por meio da soluçao seis paramétrica derivada por Pachón et al. (2012). Conclui-se que a presença do campo magnético da fonte tem efeitos apreciáveis nas quantidades físicas mencionadas acima e, portanto, a sua inclusão é necessária se se deseja descrever com mais exatidão os processos físicos que ocorrem na vizinhança deste tipo de estrelas tais como a dinâmica dos discos de acreção. Os resultados apresentados também sugerem que a precessão de campos magnéticos intensos podem introduzir correcções apreciáveis em, por exemplo, as predições da massa da estrela de neutróns feitas com base nos modelos de precessão relativista.

Sarcoma de Ewing extraóseo / Extraosseous Ewing sarcoma

Introducción. La familia de sarcomas de Ewing incluye el sarcoma de Ewing óseo, el tumor neuroectodérmico primitivo, el sarcoma de Ewing extraóseo y el tumor de Askim (sarcoma de Ewing de la pared torácica). Los sitios más comunes de estos tumores son tórax y extremidades. Estos tumores malignos surgen del hueso o de tejidos blandos. Histológicamente, se caracterizan por alta celularidad de pequeño tamaño, redondas, azules y con tendencia a formar estructuras rosetoides. Caso clínico. Se presentó el caso de un adolescente de 14 años de edad que, tres meses previos a su ingreso, inició con cefalea fronto-parietal izquierda con irradiación hacia el globo ocular. Al examen neurológico se encontró proptosis y disminución de la agudeza visual, además de atrofia papilar. Se realizó una tomografía computarizada de cráneo, donde se identificó una lesión intraorbitaria izquierda y otra parietotemporal ipsilateral. Se realizó la exéresis tumoral, reportando positividad para marcadores de tumor neuroectodérmico primitivo, vimentina y CD99. Conclusiones. El sarcoma de Ewing es extremadamente raro a nivel de la órbita. Sin embargo, es prudente considerarlo como diagnóstico diferencial en lesiones de esta región, ya que el pronóstico depende de la precisión diagnóstica temprana.

Background. The Ewing sarcoma family includes Ewing bone sarcoma, primitive neuroectodermal tumor, extraosseous Ewing's sarcoma, and Askim tumor (Ewing sarcoma of the chest wall). The most common sites of these tumors are chest and limbs. These malignancies arise from bone or soft tissues. Histologically, it is characterized by high cellularity, small, round, blue and with a tendency to form rosette structures. Case report. We report the case of a 14-year-old patient whose evolution began 3 months before admission with left frontoparietal headache radiating to the eyeball. During neurological examination, proptosis and decreased visual acuity were found, as well as papillary atrophy. Cranial computed tomography identifed a left intraorbital injury and another ipsilateral parietotemporal. Tumor exeresis was performed, reporting positive for primitive neuroectodermal tumor markers, vimentin and CD 99. Conclusions. Ewing sarcoma is extremely rare at the orbital level: however, it is prudent to consider this tumor as a differential diagnosis in lesions of this region. Prognosis depends on early diagnostic accuracy.

A morphometric study of the extraocular muscles / Estudio morfométrico de los músculos extraoculares

Extraocular muscles are important references in strabismus surgery and in placement of intraorbital devices. We analyzed extraocular muscles morphometry and possible anatomical variances of 20 orbits. We report the length, width, and points of insertion of the extraocular muscles. No anatomical variations in length, width and points of insertion were found. With regard to the rectus muscles, it was found that the superior rectus and lateral rectus are the longest muscles and that the width difference between the superior and inferior rectus is greater than that between the medial and lateral rectus and that the point of insertion of the rectus muscles has a variable morphology. The superior oblique muscle was smaller in caliber than the inferior oblique, as consistent with previous anatomical studies. Knowledge of the detailed morphology of extraocular muscles is fundamental in strabismus surgery and represents a key factor for the innovation of surgical techniques and orbital procedures.

Los músculos extraoculares son importantes en la cirugía de estrabismo y en la colocación de dispositivos intraorbitarios. Analizamos la morfometría de los músculos extraoculares y las posibles variaciones anatómicas en 20 orbitas. No encontramos variantes en longitud, anchura y sitios de inserción. Los músculos rectos superior y lateral son los mas largos; la diferencia en longitud entre los músculos rectos superior e inferior es mayor a la diferencia en longitud entre los músculos rectos medial y lateral. El músculo oblicuo superior es mas pequeño en calibre que el músculo oblicuo inferior, lo que coincide con otros estudios anatómicos. El conocimiento detallado de la morfología de los músculos extraoculares es fundamental en la cirugía de estrabismo y representa un factor clave para la innovación de técnicas quirúrgicas y procedimientos en la cavidad orbitaria.

Carcinoma de células escamosas con invasión orbitaria / Squamous cll carrcinoma with orbital extension

El carcinoma de células escamosas (CE) es una patología rara, su incidencia es del 0,13 a 1.9 casos por 100.000 habitantes, que acontece con más frecuencia en varones entre la quinta y séptima década de la vida. Presentamos el caso de una paciente de 42 años con CE con invasión a orbita de ojo izquierdo que fue sometida a exenteraciòn.

The carcinoma ofscaly cells (CE) it is a strange pathology, their incidence it is from the 0,13 to 1.9 cases for 100.000 inhabitants that it happens with more frequency in males between the fifth and seventh decade of the life. We present the case of a 42 year-old patient with CE with invasion to it orbits from left eye that was subjected to exenteracion.

Large amplitude oscillations for a class of symmetric polynomial differential systems in R³

In this paper we study a class of symmetric polynomial differential systems in R³, which has a set of parallel invariant straight lines, forming degenerate heteroclinic cycles, which have their two singular endpoints at infinity. The global study near infinity is performed using the Poincaré compactification. We prove that for all n Î N there is epsilonn > 0 such that for 0 < epsilon < epsilonn the system has at least n large amplitude periodic orbits bifurcating from the heteroclinic loop formed by the two invariant straight lines closest to the x-axis, one contained in the half-space y > 0 and the other in y < 0.

Neste trabalho estudamos uma classe de campos vetoriais polinomiais com simetria, definidos no R³ e dependendo de um parâmetro real épsilon, que possui um conjunto de retas invariantes paralelas que tendem para dois pontos singulares no infinito, formando ciclos heteroclínicos degenerados. A análise global na vizinhança dos pontos no infinito é desenvolvida utilizando-se a compactificação de Poincaré. Provamos que para todo n Î N existe épsilonn > 0 tal que, para todo 0 < épsilon < épsilonn, o sistema considerado possui pelo menos n órbitas periódicas de grande amplitude, que bifurcam do ciclo heteroclínico formado pelas duas retas invariantes mais próximas do eixo-x, uma contida no semi-espaço y > 0 e a outra contida no semi-espaço y < 0.