Bounds on the Zγγ couplings from HERA

The possibility of testing trilinear neutral gauge boson couplings in radiative neutral current scattering at HERA is analyzed using a Monte Carlo program that includes the Standard Model at tree level and the anomalous vertices. Acceptance and isolation cuts are applied as well as optimized cuts to enhance the signal from new physics. The bounds on Z\gamma\gamma couplings that can be achieved are not so stringent as present bounds, even for high luminosities, but probe a different kinematical region almost unsensitive to form factors.This work has been partially supported by the CICYT and the European Commission under contract CHRX-CT-92-0004

Effect of even and odd-order aberrations on the accommodation response.

AIM: To investigate the potential effect that odd and even-order monochromatic aberrations may have on the accommodation response of the human eye. METHODS: Eight healthy subjects with astigmatism below 1 D, best corrected visual acuity 20/20 or better and normal findings in an ophthalmic examination were enrolled. An adaptive optics system was used in order to measure the accommodation response of the subjects' eyes under different conditions: with the natural aberrations being present, and with the odd and even-order aberrations being corrected. Three measurements of accommodation response were monocularly acquired at accommodation demands ranging from 0 to 4 D (0.5 D step). RESULTS: The accommodative lag was greater for the accommodative demands of 1.5, 3, 3.5 and 4 D for the condition in which the even-order aberrations were corrected, in comparison to that obtained for the natural aberrations and corrected odd-order aberrations for the same accommodation demands. No statistically significant differences were found between the accommodation responses under the three conditions. CONCLUSION: The odd and even-order aberrations are not helping the visual system to accommodate, because their partial correction do not affect the accommodation performance

Testeo de oxímetro de pulso mediante optoelectrónica

El presente trabajo es el desarrollo de un prototipo que servirá para verificar el funcionamiento de la combinación sonda pulsioximetrica/equipo pulsioximetrico. La propuesta es un medidor funcional del tipo optoelectrónico definido en la ISO 9919:2005. El objetivo del trabajo es poder simular saturaciones de oxigeno (SpO2) y frecuencia cardiaca (pulsos por minuto – bpm) que servirán como variables para controlar el funcionamiento del equipo médico. El prototipo presentado se basa en un sistema embebido diseñado con un fin específico y a su vez planteado como un dispositivo de mano. El equipo propuesto tiene la capacidad de generar los siguientes valores: Saturación de oxígeno - 90, 95, 96, 97, 98 y 99% y Frecuencia cardíaca - 40, 60, 70, 80, 120 y 200 bpm. A su vez se tiene la posibilidad de simular condiciones de baja perfusión y además incorporar perturbaciones a la señal utilizada para testear el equipo médico. El prototipo fue corroborado con respecto a una marca de oxímetro de pulso – BCI, con lo que se obtiene conformidad del diseño propuesto, y además se efectuaron mediciones con marcas distintas de oxímetros de pulso para observar las variaciones entre estas. El prototipo está diseñado teniendo en cuenta la marca del equipo que se desea testear, generando las señales en función de la curva R de cada fabricante.Fil: Gallardo, José Rodrigo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Del Águila, R. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Laboratorio de Investigación Aplicada y Desarrollo; Argentina.Fil: Parlanti, Gustavo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Laboratorio de DSP; Argentina.Ingeniería Médic

Amplitude, Latency, and Peak Velocity in Accommodation and Disaccommodation Dynamics.

The aim of this work was to ascertain whether there are differences in amplitude, latency, and peak velocity of accommodation and disaccommodation responses when different analysis strategies are used to compute them, such as fitting different functions to the responses or for smoothing them prior to computing the parameters. Accommodation and disaccommodation responses from four subjects to pulse changes in demand were recorded by means of aberrometry. Three different strategies were followed to analyze such responses: fitting an exponential function to the experimental data; fitting a Boltzmann sigmoid function to the data; and smoothing the data. Amplitude, latency, and peak velocity of the responses were extracted. Significant differences were found between the peak velocity in accommodation computed by fitting an exponential function and smoothing the experimental data (mean difference 2.36 D/s). Regarding disaccommodation, significant differences were found between latency and peak velocity, calculated with the two same strategies (mean difference of 0.15 s and -3.56 D/s, resp.). The strategy used to analyze accommodation and disaccommodation responses seems to affect the parameters that describe accommodation and disaccommodation dynamics. These results highlight the importance of choosing the most adequate analysis strategy in each individual to obtain the parameters that characterize accommodation and disaccommodation dynamics

Evaluation of the iridocorneal angle with accommodation using optical coherence tomography.

The changes in the iridocorneal angle structure during accommodation are assessed by means of anterior segment optical coherence tomography. Thirteen right eyes were included in the study. The device used for the measurement was the Visante®omni system. The stimuli were set up at different vergences (0.0 D, -1.5 D, and -3.0 D). The angle opening distance 500 and 750, the trabecular iris space area 500 and 750, and the scleral spur angle parameters were assessed at the nasal and temporal regions. The results in the iridotrabecular angle comparing the three accommodative states of the eye did not yield any statistically significant difference at nasal or temporal angle sections. In light of our results and in the conditions of our study, the structures of the iridocorneal angle are not significantly changed with accommodation