A novel approach using nonlinear surfaces for dynamic aperture optimization in MBA synchrotron light sources.

MBA cell-based synchrotron light sources have enabled an unprecedented increase in beam coherence and brightness, greatly benefiting the scientific disciplines that rely on X-ray techniques. However, controlling the electron dynamics is a theoretical and technological challenge, due to the large number of parameters to adjust and constraints to satisfy when designing modern synchrotrons. Having versatile tools for the description and manipulation of electron dynamics could favor the design of these accelerators and lead to progress on several fronts in the understanding of matter. In this paper, a formalism based on the use of nonlinear geometric surfaces represented by polynomial quasi-invariants, to analyze and optimize the dynamic aperture of electrons in MBA storage rings, is introduced. The formalism considers on- and off-momentum particle dynamics. Within the optimization scheme, different objective functions defined in terms of the nonlinear surfaces, which are minimized using genetic algorithm methods, are proposed. A remarkable horizontal dynamic aperture exceeding 19 mm is obtained for the design particle of a synchrotron model with 86 pm [Formula: see text] rad emittance along with a dynamic aperture above 5 mm for momentum deviations of ± 3[Formula: see text]. According to the results presented, this formalism could be greatly useful for manipulating the dynamical properties of electrons in synchrotrons light sources close to the diffraction limit.

Increasing beam stability zone in synchrotron light sources using polynomial quasi-invariants.

The objective of this article is to propose a scheme to increase the stability zone of a charged particles beam in synchrotrons using a suitable objective function that, when optimized, inhibits the resonances onset in phase space and the dynamic aperture of electrons in storage rings can be improved. The proposed technique is implemented by constructing a quasi-invariant in a neighborhood of the origin of the phase space, then, by using symbolic computation software, sets of coupled differential equations for functions involved in nonlinear dynamics are obtained and solved numerically with periodic boundary conditions. The objective function is constructed by proposing that the innermost momentum solution branch of the polynomial quasi-invariant approaches to the corresponding ellipse of the linear dynamics. The objective function is optimized using a genetic algorithm, allowing the dynamic aperture to be increased. The quality of results obtained with this scheme are compared with particle tracking simulations performed with available software in the field, showing good agreement. The scheme is applied to a synchrotron light source model that can be classified as third generation due to its emittance.

Dermatozoonosis inespecífico por coleótero: reporte de tres casos en la regiòn del Chaco Paraguayo / Nonspecific dermatozoonoses by beetle: three case reports in the Chaco Paraguayo region

Las dermatozoonosis son afecciones cutáneas o cutáneo-sistémicas causadas por animales. Se analizaron tres casos de dermatitis de contacto producidas por sustancias vesicantes presentes en las familias de insectos Staphylinidae y Meloidae en residentes de la región del Chaco Boreal. La dermatitis de contacto por Staphylinidae y Meloidae, mejor llamada como dermatitis de contacto por paederina o cantaridina respectivamente, es una afección común en Paraguay pero frecuentemente subdiagnosticada o confundida con Herpes Zoster debido a sus características. Al informar sobre la epidemiología, condiciones clínicas y tratamiento de esta afección se puede prevenir su incidencia, ayudar en su proceso resolutivo y evitar diagnósticos errados que lleven a un tratamiento innecesario.

Dermatozoonosis are cutaneus or cutaneoussistemic afections caused by animals. Three cases of contact dermatitis produced by vesicant substances present in Staphylinidae and Meloidaeinsect families in residents ChacoBorealregionwere analyzed. Contact dermatitis due to Staphylinidae and Meloidae, better called Paederinor Cantharidin contact dermatitis respectively, isa common disease in Paraguay but it’s frequentlyunderdiagnosed or confused with Herpes Zoster be cause of their characteristics. Reporting on epidemiology, clinical conditions and treatment of these illness, it can prevent its occurrence, assistin their resolution process and avoid misdiagnosis that lead to an unnecessary treatment.

Randomized, controlled, prospective trial of the use of a mesh to prevent parastomal hernia.

BACKGROUND: The prevalence of terminal parastomal hernia (PH) after colostomy placement may be as high as 50%. The effect of the PH may range from discomfort to life-threatening complications. Surgical procedures for repairing PH are difficult to perform and present a high-failure rate. OBJECTIVE: To reduce the incidence of PH by implanting a lightweight mesh in the sublay position. MATERIAL AND METHODS: Randomized, controlled, prospective study. Patients were scheduled for permanent end colostomy surgery to treat cancer of the lower third of the rectum, performed by the same colorectal surgery team. An Ultrapro lightweight mesh was inserted in the sublay position in the study group. Using simple randomization, the sample size required was estimated to be 27 per group. Patients were followed-up clinically and radiologically with abdominal computed tomography by an independent clinician and a radiologist who were all blind to the aims of the study, 1 month and every 6 months after surgery. RESULTS: : The groups were homogeneous in terms of their clinical and demographic characteristics. Surgical time and postoperative morbidity were similar in the 2 groups. Mortality was 0. No mesh intolerance was reported. In the clinical follow-up (median: 29 months, range: 13-49), 11/27 (40.7%) hernias were recorded in the control group compared with 4/27 (14.8%) in the study group (P = 0.03). Abdominal computed tomography identified 14/27 (44.4%) hernias in the control group compared with 6/27 (22.2%) in the study group (P = 0.08). CONCLUSIONS: Parastomal placement of a mesh reduces the appearance of PH. The technique is safe, well-tolerated, and does not increase morbidity rates.

The prevalence of parastomal hernia after formation of an end colostomy. A new clinico-radiological classification.

INTRODUCTION: Parastomal hernia (PH) is a common complication of end colostomy, found in over 50% of patients. Abdominal computerized tomography (CT) may help diagnosis. The prevalence of PH may be higher than previously reported. We present a new CT classification for use in clinical practice. METHOD: A cross-sectional, descriptive observational study was carried out, assessing the clinical and radiological prevalence of PH in 75 patients with an end colostomy operated on since 1997. Clinical examinations were performed by a single surgeon. Abdominal CTs were assessed by a single radiologist. RESULTS: PH was observed clinically in 33 (44%) of 75 patients and 27 (82%) were symptomatic. Using the classification 0 (Normal), I (Hernial sac containing stoma loop), II (Sac containing omentum), III (Sac containing a loop other than stoma), radiological PH was observed in 35 (47%) patients. Clinical/radiological concordance (Kappa index = 0.4) increased proportionally with sac size. All type-III PHs (n = 9) were symptomatic. The combined prevalence of PH detected by one or other method was 60.8%. CONCLUSION: Clinical and radiological prevalence of PH is high. As there is no gold standard for PH detection, we recommend a combination of the two methods. A new classification for use in clinical practice is proposed.

[How are resident physicians evaluated? The residents' computerized activity record]. / 'Cómo evaluamos la actividad de los médicos internos residentes? El libro informático del residente.

INTRODUCTION: Because of the developments that have occurred in surgery in the last few years, updates are required not only in the content of resident physicians' training but also in evaluation of the knowledge acquired. The present article aims to present our experience of an integral evaluation model. This model is based on evaluation of theoretical knowledge and surgical skills. MATERIAL AND METHOD: The training program for resident physicians (medico interno residente [MIR]) has four main branches: clinical work, continuing training, research (doctorate) and evaluation of the activity performed (computerized activity record). This record allows the theoretical knowledge and skills acquired to be evaluated at the end of each rotation. Through 6-monthly evaluations, each resident's activity can be quantified over time and compared with that of other residents. RESULTS: The system was introduced in July 2004. Each resident was given his or her own database. All the activities performed were then introduced into the database. The results of overall activity and that of each resident are presented. CONCLUSIONS: The method used allows residents' integral progress to be followed-up and a completely objective evaluation to be made at the end of each year and at the end of the residency period. Widespread use of this system, or a similar system, would enable comparisons with other centers to be made under similar premises. This system could also help to unify criteria and identify deviations in training.

¿Cómo evaluamos la actividad de los médicos internos residentes? El libro informático del residente / How are resident physicians evaluated? The residents’ computerized activity record

Introducción. La evolución de nuestra especialidad en los últimos años obliga a realizar actualizaciones no sólo en contenidos, sino en una evaluación de los conocimientos aprendidos. El objetivo de este artículo es presentar nuestra experiencia en un modelo de evaluación integral. Se basa en una valoración de los conocimientos teóricos y las habilidades quirúrgicas. Material y método. El programa de formación para los MIR que hemos aplicado está fundamentado en 4 apartados: asistencial, formación continuada, investigación (doctorado) y control de la actividad realizada (libro informático del residente). Permite una evaluación de los conocimientos teóricos y las habilidades aprendidas al final de cada rotación. Mediante la creación del libro informático del residente que presentamos, se practica cada 6 meses una cuantificación de la actividad de forma continua y comparada. Resultados. En julio de 2004, iniciamos la puesta en marcha de este sistema de evaluación de la actividad de los residentes. Se entregó a cada uno de ellos su propia base de datos para que iniciara su desarrollo mediante la introducción de todas las actividades realizadas. Se presentan los resultados de la actividad global y particular de cada residente. Conclusiones. El método que utilizamos permite seguir la evolución integral del residente y realizar, al final de cada año y de la residencia, una valoración totalmente objetiva. La generalización de este método o uno similar facilitará la realización de comparaciones con otros centros y bajo premisas similares. Por otra parte, podría unificar criterios y determinar desviaciones de formación (AU)

Introduction. Because of the developments that have occurred in surgery in the last few years, updates are required not only in the content of resident physicians' training but also in evaluation of the knowledge acquired. The present article aims to present our experience of an integral evaluation model. This model is based on evaluation of theoretical knowledge and surgical skills. Material and method. The training program for resident physicians (medico interno residente [MIR]) has four main branches: clinical work, continuing training, research (doctorate) and evaluation of the activity performed (computerized activity record). This record allows the theoretical knowledge and skills acquired to be evaluated at the end of each rotation. Through 6-monthly evaluations, each resident's activity can be quantified over time and compared with that of other residents. Results. The system was introduced in July 2004. Each resident was given his or her own database. All the activities performed were then introduced into the database. The results of overall activity and that of each resident are presented. Conclusions. The method used allows residents' integral progress to be followed-up and a completely objective evaluation to be made at the end of each year and at the end of the residency period. Widespread use of this system, or a similar system, would enable comparisons with other centers to be made under similar premises. This system could also help to unify criteria and identify deviations in training (AU)