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Se hace una descripción del movimiento de una partícula en rotación haciendo uso del plano complejo y utilizando procedimientos similares al de la construcción de una teoría gauge local. El análisis permite describir el comportamiento de la partícula partiendo de la exigencia de la invariancia gauge de la ecuación de posición. Invariancia que al ser exigida conduce a la introducción de un parámetro compensatorio que se interpreta como la velocidad angular de la partícula. A partir del análisis se obtienen los efectos dinámicos que determinan su movimiento, los cuales son equivalentes a los obtenidos desde una descripción hecha respecto a un sistema de referencia en rotación haciendo uso de coordenadas polares. Este análisis presenta una manera novedosa de deducir las ecuaciones dinámicas de una partícula en rotación, lo cual representa un aporte original y pedagógico para la enseñanza de la física. A description is performed on the dynamics of a particle in rotational motion, using a complex plane and similar procedures to those implemented in the construction of a local gauge theory. The analysis allows the description of the behavior of the particle, by requiring gauge invariance in its equation of position. Requiring gauge invariance leads to the addition of an extra term in the equation, which is interpreted as the angular velocity of the particle. From this analysis, the dynamical effects that determine the motion of the particle are obtained, which are equivalent to those obtained by describing the rotating system using polar coordinates. This kind of analysis is important since it presents a new method to obtain the equations that describe the dynamics of a particle in rotational motion.

The dynamics of in situ 2D HeLa cell quasi-linear and quasi-radial colony fronts in a standard culture medium is investigated. For quasi-radial colonies, as the cell population increased, a kinetic transition from an exponential to a constant front average velocity regime was observed. Special attention was paid to individual cell motility evolution under constant average colony front velocity looking for its impact on the dynamics of the 2D colony front roughness. From the directionalities and velocity components of cell trajectories in colonies with different cell populations, the influence of both local cell density and cell crowding effects on individual cell motility was determined. The average dynamic behaviour of individual cells in the colony and its dependence on both local spatio-temporal heterogeneities and growth geometry suggested that cell motion undergoes under a concerted cell migration mechanism, in which both a limiting random walk-like and a limiting ballistic-like contribution were involved. These results were interesting to infer how biased cell trajectories influenced both the 2D colony spreading dynamics and the front roughness characteristics by local biased contributions to individual cell motion. These data are consistent with previous experimental and theoretical cell colony spreading data and provide additional evidence of the validity of the Kardar-Parisi-Zhang equation, within a certain range of time and colony front size, for describing the dynamics of 2D colony front roughness., Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas

Biofilms are bacterial aggregates that grow on moist surfaces. Thin homogeneous biofilms naturally formed on the walls of conducts may serve as biosensors, providing information on the status of microsystems (MEMS) without disrupting them. However, uncontrolled biofilm growth may largely disturb the environment they develop in, increasing the drag and clogging the tubes. To ensure controlled biofilm expansion we need to understand the effect of external variables on their structure. We formulate a hybrid model for the computational study of biofilms growing in laminar microflows. Biomass evolves according to stochastic rules for adhesion, erosion and motion, informed by numerical approximations of the flow fields at each stage. The model is tested studying the formation of streamers in three dimensional corner flows, gaining some insight on the effect of external variables on their structure.

Las lesiones en la médula espinal representan un porcentaje importante como causa de discapacidad en México y en el mundo, siendo la tercera causa con un porcentaje superior a 25%. Este tipo de pacientes sufre múltiples complicaciones y una de ellas es la que corresponde al sistema urológico al que muchas veces no se le da un seguimiento de manera regular. Dentro de las lesiones de las vías neurológicas, que inervan a la vejiga, pueden afectar a uno o varios aspectos de la fisiología, ya sea su fase de llenado, de almacenamiento o de vaciamiento, lo anterior según el área nerviosa alcanzada y la naturaleza de la lesión; estas lesiones deben ser manejadas por el mismo urólogo que debe seleccionar la opción terapéutica adecuada en su ámbito de competencia, tomando en cuenta los pros y contras de cada una de ellas, ya que esto tendrá una repercusión en la calidad de vida del paciente, así como continuar un programa de seguimiento para la detección de complicaciones de manera oportuna. Particularmente el cateterismo urinario es pilar fundamental para el manejo de las lesiones medulares postraumáticas, ya que puede contribuir a la disminución de las complicaciones. As lesões da medula espinhal representam um percentual significativo das causas de deficiência no México e no mundo, sendo a terceira causa, com um percentual acima de 25%. Estes pacientes sofrem de múltiplas complicações, e uma delas é do sistema urológico, ao qual muitas vezes não é dado seguimento adequado. Entre as lesões das vias neurológicas que enervam a bexiga, pode ser afetados um ou mais aspectos da fisiologia, seja na fase de o armazenamento, esvaziamento ou enchimento, dependendo da área do nervo afectado e da natureza da lesão, tais lesões devem ser tratadas pelo urologista, que deve selecionar a opção terapêutica apropriada em sua área de competência, levando em conta os prós e contras de cada um, pois isso impacta a qualidade de vida dos pacientes, bem como continuar um programa de monitoramento para a detecção de complicações em tempo hábil. A cateterização urinária é, particularmente, um pilar fundamental para a gestão da lesão traumática da medula espinal, uma vez que pode contribuir para a redução de complicações. Spinal cord injuries represent a significant percentage of causes of disability in Mexico and worldwide, being the third largest cause, with a percentage of more than 25%. These patients suffer from multiple complications, one of which relates to the urological system, which often does not receive appropriate follow-up. Among the lesions of the neurological pathways that innervate the bladder, one or more aspects of its physiology may be affected, whether in the filling, storage or voiding phases, depending on the nerve area affected and the nature of the injury. These lesions should be handled by the urologist, who should select the most suitable therapeutic option within his or her area of competence and taking into account the advantages and disadvantages of each option, as this will have an impact on the quality of life of the patient, as well as continuing a monitoring program for timely detection of complications. Urinary catheterization is, in particular, a fundamental pillar for the management of traumatic lesion of the spinal cord, as it can help reduce complications.