Characterization of multilayer stack parameters from X-ray reflectivity data using the PPM program: measurements and comparison with TEM results

Future hard (10 -100 keV) X-ray telescopes (SIMBOL-X, Con-X, HEXIT-SAT, XEUS) will implement focusing optics with multilayer coatings: in view of the production of these optics we are exploring several deposition techniques for the reflective coatings. In order to evaluate the achievable optical performance X-Ray Reflectivity (XRR) measurements are performed, which are powerful tools for the in-depth characterization of multilayer properties (roughness, thickness and density distribution). An exact extraction of the stack parameters is however difficult because the XRR scans depend on them in a complex way. The PPM code, developed at ERSF in the past years, is able to derive the layer-by-layer properties of multilayer structures from semi-automatic XRR scan fittings by means of a global minimization procedure in the parameters space. In this work we will present the PPM modeling of some multilayer stacks (Pt/C and Ni/C) deposited by simple e-beam evaporation. Moreover, in order to verify the predictions of PPM, the obtained results are compared with TEM profiles taken on the same set of samples. As we will show, PPM results are in good agreement with the TEM findings. In addition, we show that the accurate fitting returns a physically correct evaluation of the variation of layers thickness through the stack, whereas the thickness trend derived from TEM profiles can be altered by the superposition of roughness profiles in the sample image

Prevalencia de enteroparásitos en la población pediátrica de Pampayasta Sur

El objetivo del presente trabajo fue establecer la prevalencia de entero parásitos en la población infantil que concurre al colegio primario de Pampayasta Sur. Los estudios fueron realizados en materia fecal recogida de manera seriada durante cinco días, en formol al 5% y escobillado anal para investigación de E vermicularis. Las muestras fueron procesadas por métodos de concentración (Telleman) y flotación (Willis). Se estudiaron 51 pacientes (34%) sobre una población total de 150 niños que concurren al colegio primario. Los resultados mostraron que el 60,78% de los niños estudiados (31/51) estaban parasitados por al menos un entero parásito. La prevalencia de los coproparasitológicos fue del 54,90% (28/51), mientras que los escobillados anales fueron del 37,25% (19/51). La prevalencia encontrada por párasito fue la siguiente: E. vermicularis 37,25% (n: 19); G. lamblia y B hominis 29,41% (n: 15); E. coli 17,65% (n: 9); E nana 7,84% (n 4) y I. butschlii 3,92% (n: 2). No se recuperaron geohelmintos. Esto se debería al nivel socio cultural de la gente, como así también a los tratamientos antiparasitarios masivos implementados por el gobierno nacional. Estudios de este tipo son muy importantes, ya que permiten implementar medidas preventivas y por ende futuras acciones para su erradicación

Advancements in ion beam figuring of very thin glass plates

The high-quality surface characteristics, both in terms of figure error and of micro-roughness, required on the mirrors of a high angular resolution x-ray telescope are challenging, but in principle well suited with a deterministic and non-contact process like the ion beam figuring. This process has been recently proven to be compatible even with very thin (thickness around 0.4mm) sheet of glasses (like D263 and Eagle). In the last decade, these types of glass have been investigated as substrates for hot slumping, with residual figure errors of hundreds of nanometres. In this view, the mirrors segments fabrication could be envisaged as a simple two phases process: a first replica step based on hot slumping (direct/indirect) followed by an ion beam figuring which can be considered as a post-fabrication correction method. The first ion beam figuring trials, realized on flat samples, showed that the micro-roughness is not damaged but a deeper analysis is necessary to characterize and eventually control/compensate the glass shape variations. In this paper, we present the advancements in the process definition, both on flat and slumped glass samples

The future of Cybersecurity in Italy: Strategic focus area

This volume has been created as a continuation of the previous one, with the aim of outlining a set of focus areas and actions that the Italian Nation research community considers essential. The book touches many aspects of cyber security, ranging from the definition of the infrastructure and controls needed to organize cyberdefence to the actions and technologies to be developed to be better protected, from the identification of the main technologies to be defended to the proposal of a set of horizontal actions for training, awareness raising, and risk management

Progress in ion beam figuring of very thin slumped glass plates for lightweight x-ray telescope

The combination of the hot slumping and the Ion Beam Figuring (IBF) technologies can be a very competitive solution for the realization of x-ray optics with excellent imaging capabilities and high throughput. While very thin mirrors segments can be realized by slumping with residual figure errors below few hundreds of nanometres, a non-contact and deterministic process (dependent on dwell time), like IBF, is a very effective post facto correction, as it avoids all the problems due to the handling and the supporting system. In the last years, the two processes were proven compatible with very thin sheet of Eagle XG glasses (0.4 mm thickness). Nevertheless, the fast convergence of the process is a key factor to limit the cost of the mirror plate production. A deeper characterization of removal function stability showed that its repeatability between each run has to be improved for a real enhancement of the process convergence factor. A new algorithm based on de-convolution has been implemented and tested, with important advantages in terms of calculation speed, minimum material removal and optimization possibilities. By analysing the metrological data of test slumped glasses, we showed how the IBF is effective in the correction of figure errors on scales above 8 - 10 mm. An overall figuring time of few hours is required with surface error around 100 nm rms. Thanks to the thickness measurement data, which are performed in transmission mode with an interferometric set-up, we demonstrated that it is possible to disentangle the effective amount of the material removed and the deformations introduced during the process

Pensando un rediseño de agroecosistemas campesinos del Chaco Semiárido argentino: el caso de la asociación campesinos del Valle del Conlara (San Luis, Argentina)

La expansión del modelo de agricultura industrial en la región chaqueña ha generado fuertes cambios ambientales y sociales (desmontes masivos, pérdida de biodiversidad, expulsión de campesinos). Desde 2009, estudiantes, docentes e investigadores de la Universidad de Buenos Aires trabajan junto a campesinos y técnicos locales de la Asociación Campesinos del Valle del Conlara (San Luis, Argentina; ACVC), en pensar cómo mejorar la cantidad, calidad y estabilidad de la oferta forrajera del monte nativo. Partimos de una caracterización preliminar de los agroecosistemas campesinos, publicada en SOCLA (2013). Aquí, nos proponemos compartir las reflexiones sobre alternativas de rediseño y manejo agroecológico, así como los trabajos que se realizaron en la ACVC en este sentido. Este trabajo se enmarca dentro de un proyecto interdisciplinario, cuyo propósito es contribuir al fortalecimiento de la autonomía ecológica y económica de los campesinos, una alternativa al modelo hegemónico.Eje: B5 Sistemas de conocimiento (Relatos de experiencias)Facultad de Ciencias Agrarias y Forestale

Pensando un rediseño de agroecosistemas campesinos del Chaco Semiárido argentino: el caso de la asociación campesinos del Valle del Conlara (San Luis, Argentina)

La expansión del modelo de agricultura industrial en la región chaqueña ha generado fuertes cambios ambientales y sociales (desmontes masivos, pérdida de biodiversidad, expulsión de campesinos). Desde 2009, estudiantes, docentes e investigadores de la Universidad de Buenos Aires trabajan junto a campesinos y técnicos locales de la Asociación Campesinos del Valle del Conlara (San Luis, Argentina; ACVC), en pensar cómo mejorar la cantidad, calidad y estabilidad de la oferta forrajera del monte nativo. Partimos de una caracterización preliminar de los agroecosistemas campesinos, publicada en SOCLA (2013). Aquí, nos proponemos compartir las reflexiones sobre alternativas de rediseño y manejo agroecológico, así como los trabajos que se realizaron en la ACVC en este sentido. Este trabajo se enmarca dentro de un proyecto interdisciplinario, cuyo propósito es contribuir al fortalecimiento de la autonomía ecológica y económica de los campesinos, una alternativa al modelo hegemónico.Eje: B5 Sistemas de conocimiento (Relatos de experiencias)Facultad de Ciencias Agrarias y Forestale

Pensando un rediseño de agroecosistemas campesinos del Chaco Semiárido argentino: el caso de la asociación campesinos del Valle del Conlara (San Luis, Argentina)

La expansión del modelo de agricultura industrial en la región chaqueña ha generado fuertes cambios ambientales y sociales (desmontes masivos, pérdida de biodiversidad, expulsión de campesinos). Desde 2009, estudiantes, docentes e investigadores de la Universidad de Buenos Aires trabajan junto a campesinos y técnicos locales de la Asociación Campesinos del Valle del Conlara (San Luis, Argentina; ACVC), en pensar cómo mejorar la cantidad, calidad y estabilidad de la oferta forrajera del monte nativo. Partimos de una caracterización preliminar de los agroecosistemas campesinos, publicada en SOCLA (2013). Aquí, nos proponemos compartir las reflexiones sobre alternativas de rediseño y manejo agroecológico, así como los trabajos que se realizaron en la ACVC en este sentido. Este trabajo se enmarca dentro de un proyecto interdisciplinario, cuyo propósito es contribuir al fortalecimiento de la autonomía ecológica y económica de los campesinos, una alternativa al modelo hegemónico.Eje: B5 Sistemas de conocimiento (Relatos de experiencias)Facultad de Ciencias Agrarias y Forestale

Testing the robustness of controllers for self-adaptive systems

Self-Adaptive systems are software-intensive systems endowed with the ability to respond to a variety of changes that may occur in their environment, goals, or the system itself, by adapting their structure and behavior at run-time in an autonomous way. Controllers are complex components incorporated in self-adaptive systems, which are crucial to their function since they are in charge of adapting the target system by executing actions through effectors, based on information monitored by probes. However, although controllers are becoming critical in many application domains, so far very little has been done to assess their robustness. In this paper, we propose an approach for evaluating the robustness of controllers for self-adaptive software systems, aiming to identify faults in their design. Our proposal considers the stateful nature of the controller, and identifies a set of robustness tests, which includes the provision of mutated inputs to the interfaces between the controller and the target system (i.e., probes). The feasibility of the approach is evaluated on Rainbow, a framework for architecture-based self-adaptation, and in the context of the Znn.com case study