Dynamical coupled-channels: the key to understanding resonances

Recent developments on a dynamical coupled-channels model of hadronic and electromagnetic production of nucleon resonances are summarized.Comment: Invited Plenary talk at the 20th European Conference on Few-Body Problems in Physics (EFB20), September 10-14 2007, Pisa, Italy. To appear in the proceedings in Few-Body System

Slope failure in Caracas, Venezuela: The influence of squatter settlement

In Caracas, Venezuela, landslides have become an increasing problem frequently associated with the rainy season and the creation of more vulnerable areas by the urbanization process. Their effects have been particularly evident in the squatter settlements or barrios in the hillsides surrounding Caracas. The purpose of this research is to examine the incidence of slope failure in the barrios. An account of the urban growth of Caracas is given in order to illustrate how population has been progressively occupying the valley and its hillsides. A data set of 205 slope failures which occurred over a six year period is set up. The slope failures in the Metropolitan Area are analyzed both spatially and over time in order to elucidate some of the factors responsible for their incidence. Besides location and date of occurrence, the data set incorporates rainfall seasonality and cumulative totals, lithology, slope angle, type of mass movement, and location within the urban context. The role of the rainfall as a triggering factor for the slope failures is examined. Cumulative rainfall values are considered for 10, 30 days and seasonally. With the help of a sequence of aerial photographs, the evolution of slope failure in barrio El Cipres is used to examine the links between the settlement process and the evolution of the local geomorphology. A Landslide Susceptibility Map is then produced. The research shows that rainfall plays an important role in the incidence of slope failures, but its influence in barrios is also compounded by other factors such as enhanced infiltration and the changes in slope produced by the settlements process. In this connection improvements in services and the consolidation of the barrio may add to the problem if they are not carefully planned

Displacement of Cranial Reference Landmarks Used in Jarabak and Ricketts Cephalometric Analysis During Active Growth

Indexación: Web of Science; Scielo.RESUMEN: El objetivo de este trabajo fue evaluar el desplazamiento de los puntos craneales: Nasion, Silla, Basion, Porion, Orbitario y Pterigoideo, utilizados como referencia en los análisis cefalométricos de Jarabak y Ricketts durante el crecimiento activo. Se seleccionaron 120 telerradiografías de perfil en formato digital, correspondientes a 60 pacientes con 2 telerradiografías cada uno, tomadas con un intervalo de tiempo mínimo de 1 año (T1 y T2), en donde T1 se encuentra antes o durante el peak de crecimiento según el Estado de Maduración Cervical Vertebral (CVM) I, II ó III de Baccetti y T2 en estadio CVM IV,V,VI (después del peak de crecimiento). Un examinador previamente calibrado, ubicó los puntos analizados y para evaluar su desplazamiento, se realizaron mediciones en T1 y T2 (3 variables para cada punto), usando como referencia 2 planos que no se modifican a partir de los 5 años de edad (LCB y Vert-T). Para determinar el desplazamiento de los puntos, se calculó la variación promedio observada entre T1 y T2 y se realizó la prueba t para muestras pareadas o Wilcoxon (según distribución) para determinar la existencia de diferencias significativas. Además, se comparó la muestra por sexo, CVM inicial y CVM final. Se encontraron variaciones entre T1 y T2 en todas las medidas, aunque sólo en 5 de ellas se encontraron diferencias significativas; no se encontró diferencias al comparar por sexo, CVM inicial y final. Es así como podemos concluir que todos los puntos craneales analizados sufren desplazamiento durante el crecimiento. Los puntos Basion y Orbitario son los que sufren mayor desplazamiento. Es necesario analizar las implicancias de estas variaciones en los resultados obtenidos de los análisis cefalométrico y evaluar la necesidad de utilizar puntos de referencia alternativos.SUMMARY: The objective of this study was to evaluate the displacement of cranial reference points: Nasion, Sella, Basion, Porion, Orbitale and Pterygomaxillary, used in Jarabak and Ricketts cephalometric analysis, during active growth. Hundred and twenty digitalized lateral telerradiographies, corresponding to 60 patients (2 teleradiographies each one), were collected. The radiographies were taken with a minimum interval of one year between them (T1 and T2), where T1 is taken before or during the pubertal growth peack according to the cervical vertebral maturation stages developed by baccetti (CVM) I, II or III and T2 in CVM IV,V,VI (after the growth peak). Then, a previously calibrated examinator marked reference points and cephalometric measurements were taken (2 variables for each landmark). Measurements were made using craniofacial stable structures as references (stable basicranial line and Vertical T). To detect displacement in the landmark positions, t test or Wilcoxon test according to the distribution of each variable, was used to compare the data between T1 and T2. Also, comparisons were made by sex, and by initial and final CVM. All of the variables have variations between T1 y T2, but only 5 have a statistically significant difference. There were no differences between sexes and at initial and final CVM. In conclusion, all of the reference landmarks analyzed had displacement during active growth. Point Basion and Orbitale suffered the largest displacement. It is necessary to analyze the clinical implications of this displacement in order to evaluate the convenience of using alternative reference landmarks.http://ref.scielo.org/rf877

Enhanced Parallel Generation of Tree Structures for the Recognition of 3D Images

Segmentations of a digital object based on a connectivity criterion at n-xel or sub-n-xel level are useful tools in image topological analysis and recognition. Working with cell complex analogous of digital objects, an example of this kind of segmentation is that obtained from the combinatorial representation so called Homological Spanning Forest (HSF, for short) which, informally, classifies the cells of the complex as belonging to regions containing the maximal number of cells sharing the same homological (algebraic homology with coefficient in a field) information. We design here a parallel method for computing a HSF (using homology with coefficients in Z/2Z) of a 3D digital object. If this object is included in a 3D image of m1 × m2 × m3 voxels, its theoretical time complexity order is near O(log(m1 + m2 + m3)), under the assumption that a processing element is available for each voxel. A prototype implementation validating our results has been written and several synthetic, random and medical tridimensional images have been used for testing. The experiments allow us to assert that the number of iterations in which the homological information is found varies only to a small extent from the theoretical computational time.Ministerio de Economía y Competitividad MTM2016-81030-

Kinematics of gas and stars in circumnuclear star-forming regions of early type spirals

(Abbr.) We present high resolution (R~20000) spectra in the blue and the far red of cicumnuclear star-forming regions (CNSFRs) in three early type spirals (NGC3351, NGC2903 and NGC3310) which have allowed the study of the kinematics of stars and ionized gas in these structures and, for the first time, the derivation of their dynamical masses for the first two. In some cases these regions, about 100 to 150 pc in size, are seen to be composed of several individual star clusters with sizes between 1.5 and 4.9 pc estimated from Hubble Space Telescope (HST) images. The stellar dispersions have been obtained from the Calcium triplet (CaT) lines at $\lambda\lambda$ 8494,8542,8662 \AA, while the gas velocity dispersions have been measured by Gaussian fits to the H$\beta$ and [OIII] $\lambda\lambda$ 5007 \AA lines on the high dispersion spectra. Values of the stellar velocity dispersions are between 30 and 68 km/s. We apply the virial theorem to estimate dynamical masses of the clusters, assuming that systems are gravitationally bounded and spherically symmetric, and using previously measured sizes. The measured values of the stellar velocity dispersions yield dynamical masses of the order of 10$^7$ to 10$^8$ solar masses for the whole CNSFRs. Stellar and gas velocity dispersions are found to differ by about 20 to 30 km/s with the H$\beta$ emission lines being narrower than both the stellar lines and the [OIII] $\lambda\lambda$ 5007 \AA lines. The twice ionized oxygen, on the other hand, shows velocity dispersions comparable to those shown by stars, in some cases, even larger. We have found indications of the presence of two different kinematical components in the ionized gas of the regions...Comment: 4 pages, proceeding of the meeting "Young massive star clusters - Initial conditions and environments", Granada, Spain, 200

Haro15: Is it actually a low metallicity galaxy?

We present a detailed study of the physical properties of the nebular material in multiple knots of the blue compact dwarf galaxy Haro 15. Using long slit and echelle spectroscopy, obtained at Las Campanas Observatory, we study the physical conditions (electron density and temperature), ionic and total chemical abundances of several atoms, reddening and ionization structure. The latter was derived by comparing the oxygen and sulphur ionic ratios to their corresponding observed emission line ratios (the eta and eta' plots) in different regions of the galaxy. Applying direct and empirical methods for abundance determination, we perform a comparative analysis between these regions.Comment: (Poster paper) 2 pages, 2 figure

Speeding up antidynamical Casimir effect with nonstationary qutrits

The antidynamical Casimir effect (ADCE) is a term coined to designate the coherent annihilation of excitations due to resonant external perturbation of system parameters, allowing for extraction of quantum work from nonvacuum states of some field. Originally proposed for a two-level atom (qubit) coupled to a single cavity mode in the context of nonstationary quantum Rabi model, it suffered from very low transition rate and correspondingly narrow resonance linewidth. In this paper we show analytically and numerically that the ADCE rate can be increased by at least one order of magnitude by replacing the qubit by an artificial three-level atom (qutrit) in a properly chosen configuration. For the cavity thermal state we demonstrate that the dynamics of the average photon number and atomic excitation is completely different from the qubit's case, while the behavior of the total number of excitations is qualitatively similar yet significantly faster.Comment: 9 pages, 4 figure

Prótesis de hombro tras fractura de húmero proximal: indicaciones, técnica quirúrgica y resultados

Las fracturas de húmero proximal suponen el 5% de todas las fracturas. La mayoría pueden ser tratadas de forma conservadora, sin embargo, el manejo de las fracturas desplazadas o complejas resulta controvertido. La hemiartroplastia está indicada en fracturas en tres y cuatro fragmentos de húmero proximal en ancianos con baja densidad ósea y en aquellas fracturas no susceptibles de tratamiento con osteosíntesis. Proporciona un buen control del dolor tras la fractura, sin embargo, los resultados funcionales son pobres si no se consigue una reparación anatómica de las tuberosidades. Respecto a la hemiartroplastia, la prótesis total inversa de hombro obtiene resultados funcionales más predecibles en términos de abducción, elevación anterior y alivio del dolor, sin embargo, presenta una tasa de complicaciones elevada y sus resultados a largo plazo son desconocidos.Proximal humeral fractures account for 5% of all fractures. Although the majority can be managed non-operatively, the optimal treatment of displaced or complex fractures remains controversial. Hemiarthroplasty is indicated for three and four-part proximal humeral fractures in elderly patients with poor bone stock and fractures in which internal fixation is difficult or unreliable. Hemiarthroplasty provides patients with reliable pain relief. However, funtional results are poor if anatomical repair of the tuberosities is not achieved. Reverse total shoulder prosthesis provides more predictable functional outcomes in terms of abduction, anterior elevation and pain relief, but has a high rate of complications and its long-term results are unknow