Classification of Mediterranean hedgerows: A methodological approximation.

The present paper addresses the methodology carried out to obtain a new classification of hedgerow networks in the Mediterranean region using GIS and Remote Sensing. A new methodology has been developed due to the need to establish a typification of the hedgerows in this sector of southern Europe, where the variable conditioning the localization, area and type of these landscapes is degree of surface soil moisture. In the continental Mediterranean context, this age-old agricultural system is closely linked to access to, and management of, water resources, which are vital in the dry season. For this reason, we mapped the hedgerow network of a continental Mediterranean mountain, establishing different levels of surface soil moisture provided by images from the satellite Sentinel-2. The results render three types of hedgerows: moist, semi-moist and dry, each one presenting clearly differentiated localizations and characteristics. To this can be added the analysis of the evolution of their area from 1956 to the present time from aerial pictures and satellite images and their correlation with surface soil moisture and slope. We present results on this tested method from the central sector of the Iberian Peninsula, Spain.•The presented procedure focuses on a new classification of hedgerow networks in the Mediterranean region based on the degree of surface soil moisture.•The method stablishes different levels of surface soil moisture provided by images from the satellite Sentinel-2.•The procedure allows us to analyze and correlate the evolution of Mediterranean hedgerows with surface soil moisture.

Impact of Gamma Radiation on Dynamic RDSON Characteristics in AlGaN/GaN Power HEMTs.

GaN high-electron-mobility transistors (HEMTs) are promising next-generation devices in the power electronics field which can coexist with silicon semiconductors, mainly in some radiation-intensive environments, such as power space converters, where high frequencies and voltages are also needed. Its wide band gap (WBG), large breakdown electric field, and thermal stability improve actual silicon performances. However, at the moment, GaN HEMT technology suffers from some reliability issues, one of the more relevant of which is the dynamic on-state resistance (RON_dyn) regarding power switching converter applications. In this study, we focused on the drain-to-source on-resistance (RDSON) characteristics under 60Co gamma radiation of two different commercial power GaN HEMT structures. Different bias conditions were applied to both structures during irradiation and some static measurements, such as threshold voltage and leakage currents, were performed. Additionally, dynamic resistance was measured to obtain practical information about device trapping under radiation during switching mode, and how trapping in the device is affected by gamma radiation. The experimental results showed a high dependence on the HEMT structure and the bias condition applied during irradiation. Specifically, a free current collapse structure showed great stability until 3.7 Mrad(Si), unlike the other structure tested, which showed high degradation of the parameters measured. The changes were demonstrated to be due to trapping effects generated or enhanced by gamma radiation. These new results obtained about RON_dyn will help elucidate trap behaviors in switching transistors.

On the Entropy of Oscillator-Based True Random Number Generators under Ionizing Radiation.

The effects of ionizing radiation on field-programmable gate arrays (FPGAs) have been investigated in depth during the last decades. The impact of these effects is typically evaluated on implementations which have a deterministic behavior. In this article, two well-known true-random number generators (TRNGs) based on sampling jittery signals have been exposed to a Co-60 radiation source as in the standard tests for space conditions. The effects of the accumulated dose on these TRNGs, an in particular, its repercussion over their randomness quality (e.g., entropy or linear complexity), have been evaluated by using two National Institute of Standards and Technology (NIST) statistical test suites. The obtained results clearly show how the degradation of the statistical properties of these TRNGs increases with the accumulated dose. It is also notable that the deterioration of the TRNG (non-deterministic component) appears before that the degradation of the deterministic elements in the FPGA, which compromises the integrated circuit lifetime.

Estudio de los abandonos de tratamiento / A sutdy of treatment drop-out

El abandono del tratamiento es un fenómeno generalizado que distorsiona el funcionamiento de los servicios médicos y puede acabar afectando a la propia evolución de los pacientes. Para investigar sus causas, se ha estudiado su incidencia y los factores potencialmente asociados, en una cohorte de pacientes mayores de 17 años ingresados por primera vez en nuestro Servicio de Salud Mental durante el año 1997. Los resultados confirman una elevada tasa de abandonos (62.7 per cent), formado por un grupo heterogéneo en el que la primera causa es la mejoría (43 per cent), seguida de la ineficacia del tratamiento (23 per cent). Como factores predictivos del abandono, únicamente hemos podido distinguir el número menor de contactos y el tratamiento con un neuropsiquiatra. Los abandonos precoces (con sólo 4 contactos) suponen el 30 per cent del total, y en general se producen por mejoría y, sobre todo, entre los pacientes atendidos por los psiquiatras. No parece que el abandono agrave la evolución de los pacientes, en parte quizás porque en los procesos más graves (psicosis) se consigue mantener un buen cumplimento terapéutico (AU)