Modeling the Spatial Spread of Chagas Disease.

The aim of this work is to understand the spatial spread of Chagas disease, which is primarily transmitted by triatomines. We propose a mathematical model using a system of partial differential reaction-diffusion equations to study and describe the spread of this disease in the human population. We consider the respective subclasses of infected and uninfected individuals within the human and triatomine populations.

Energy-dependent dead-time correction in digital pulse processors applied to silicon drift detector's X-ray spectra.

Dead-time effects in X-ray spectra taken with a digital pulse processor and a silicon drift detector were investigated when the number of events at the low-energy end of the spectrum was more than half of the total, at counting rates up to 56 kHz. It was found that dead-time losses in the spectra are energy dependent and an analytical correction for this effect, which takes into account pulse pile-up, is proposed. This and the usual models have been applied to experimental measurements, evaluating the dead-time fraction either from the calculations or using the value given by the detector acquisition system.

Paleohydrological Changes in Highland Desert Rivers and Human Occupation, 7000-3000 Cal. Yr B.P., South-Central Andes, Argentina.

This article focuses on local paleohydrological changes experienced by the Las Pitas and Miriguaca Rivers in the south-central Andes of Argentina and their impacts on hunter-gatherers as they transitioned to food-producing communities 7000-3000 cal. yr B.P.

Experimental HPGe coaxial detector response and efficiency compared to Monte Carlo simulations.

The peak efficiency for photons hitting the frontal surface of a medium volume n-type HPGe coaxial detector is mapped using acutely collimated beams of energies between 31 and 383 keV from a (133)Ba radioactive source. Simulated values obtained with the Monte Carlo radiation transport code penelope, using a model that respected actual detector dimensions and physical constants while varying dead-layer thicknesses, allowed us to fit the experimental results in the detector bulk but not near its rim. The spectra of a (137)Cs source were measured using the detector shielded from the natural background radiation, with and without a broad angle collimator.

Optical transition radiation used in the diagnostic of low energy and low current electron beams in particle accelerators.

Optical transition radiation (OTR) plays an important role in beam diagnostics for high energy particle accelerators. Its linear intensity with beam current is a great advantage as compared to fluorescent screens, which are subject to saturation. Moreover, the measurement of the angular distribution of the emitted radiation enables the determination of many beam parameters in a single observation point.