Magnetic pattern at supergranulation scale: the Void Size Distribution

The large-scale magnetic pattern of the quiet sun is dominated by the magnetic network. This network, created by photospheric magnetic fields swept into convective downflows, delineates the boundaries of large scale cells of overturning plasma and exhibits voids in magnetic organization. Such voids include internetwork fields, a mixed-polarity sparse field that populate the inner part of network cells. To single out voids and to quantify their intrinsic pattern a fast circle packing based algorithm is applied to 511 SOHO/MDI high resolution magnetograms acquired during the outstanding solar activity minimum between 23 and 24 cycles. The computed Void Distribution Function shows a quasi-exponential decay behavior in the range 10-60 Mm. The lack of distinct flow scales in such a range corroborates the hypothesis of multi-scale motion flows at the solar surface. In addition to the quasi-exponential decay we have found that the voids reveal departure from a simple exponential decay around 35 Mm.Comment: 6 pages, 8 figures, to appear in Astronomy and Astrophysic

Multiple field-of-view MCAO for a Large Solar Telescope: LOST simulations

In the framework of a 4m class Solar Telescope we studied the performance of the MCAO using the LOST simulation package. In particular, in this work we focus on two different methods to reduce the time delay error which is particularly critical in solar adaptive optics: a) the optimization of the wavefront reconstruction by reordering the modal base on the basis of the Mutual Information and b) the possibility of forecasting the wavefront correction through different approaches. We evaluate these techniques underlining pros and cons of their usage in different control conditions by analyzing the results of the simulations and make some preliminary tests on real data.Comment: 10 pages, 5 figures to be published in Adaptive Optics Systems II (Proceedings Volume) Proceedings of SPI

JP3D compression of solar data-cubes: photospheric imaging and spectropolarimetry

Hyperspectral imaging is an ubiquitous technique in solar physics observations and the recent advances in solar instrumentation enabled us to acquire and record data at an unprecedented rate. The huge amount of data which will be archived in the upcoming solar observatories press us to compress the data in order to reduce the storage space and transfer times. The correlation present over all dimensions, spatial, temporal and spectral, of solar data-sets suggests the use of a 3D base wavelet decomposition, to achieve higher compression rates. In this work, we evaluate the performance of the recent JPEG2000 Part 10 standard, known as JP3D, for the lossless compression of several types of solar data-cubes. We explore the differences in: a) The compressibility of broad-band or narrow-band time-sequence; I or V stokes profiles in spectropolarimetric data-sets; b) Compressing data in [x,y,$\lambda$] packages at different times or data in [x,y,t] packages of different wavelength; c) Compressing a single large data-cube or several smaller data-cubes; d) Compressing data which is under-sampled or super-sampled with respect to the diffraction cut-off

Fotopolimerizzazione di miscele siliconiche con componenti fluorurati e ossietilenici antivegetativi

Lo scopo di questo lavoro di tesi consiste nella preparazione di rivestimenti protettivi in grado di limitare il biofouling marino e di permettere il distacco di macro/microrganismi eventualmente aderiti. Questi rivestimenti anfifilici saranno ottenuti tramite fotopolimerizzazione di differenti formulazioni preparate a partire da monomeri con diversa filia/fobia: un (di)metacrilato polisilossanico idrofobo, un metacrilato poliossietilenico (idrofilo) ed un acrilato fluorurato (idrofobo/lipofobo). Successivamente, i film polimerici verranno caratterizzati con analisi in massa e di superficie. Più specificatamente, la caratterizzazione in massa prevederà misure di calorimetria differenziale a scansione (DSC), analisi termogravimetrica (TGA), analisi meccaniche (quali INSTRON, DMA) e prove di rigonfiamento in acqua. La caratterizzazione di superficie includerà misure dell’angolo di contatto statico con liquidi bagnanti a diversa polarità e spettroscopia fotoelettronica a raggi X. Saranno inoltre effettuati saggi biologici di tossicità verso organismi modello, quali Vibrio fischeri e Dunaliella tertiolecta, e di stanziamento e rimozione di organismi, quali la macroalga Ulva linza, la diatomea Navicula salinicola, ed il serpulide Ficopomatus enigmaticus

Design and development of an Electrochemical milling System (ECMIL)

The thesis is about designing and developing of a non-conventional machining system aimed on using electro chemical reactions for milling processes, called Electrochemical Milling System (ECMIL)

3D photospheric velocity field of a Supergranular cell

We investigate the plasma flow properties inside a Supergranular (SG) cell, in particular its interaction with small scale magnetic field structures. The SG cell has been identified using the magnetic network (CaII wing brightness) as proxy, applying the Two-Level Structure Tracking (TST) to high spatial, spectral and temporal resolution observations obtained by IBIS. The full 3D velocity vector field for the SG has been reconstructed at two different photospheric heights. In order to strengthen our findings, we also computed the mean radial flow of the SG by means of cork tracing. We also studied the behaviour of the horizontal and Line of Sight plasma flow cospatial with cluster of bright CaII structures of magnetic origin to better understand the interaction between photospheric convection and small scale magnetic features. The SG cell we investigated seems to be organized with an almost radial flow from its centre to the border. The large scale divergence structure is probably created by a compact region of constant up-flow close to the cell centre. On the edge of the SG, isolated regions of strong convergent flow are nearby or cospatial with extended clusters of bright CaII wing features forming the knots of the magnetic network.Comment: 7 pages, submitted to A&A, referee's comments include

Programa de cribado de enfermedades endocrino-metabólicas: Importancia y diferencias por comunidades autónomas

Los programas de cribado neonatal constituyen uno de los pilares fundamentales a nivel de prevención en materia de Salud Pública. Éstos tienen como finalidad identificar en los recién nacidos una serie de enfermedades que de no tratarse lo más precozmente posible pueden producir graves consecuencias. El personal de enfermería es un eslabón fundamental para la puesta en marcha de estos programas. Es imprescindible realizar una buena praxis para la obtención de la muestra de sangre a analizar, así como informar a los padres de todos los aspectos relacionados con el programa al que acceden sus hijos. En España, cada Comunidad Autónoma regula su propio programa de cribado neonatal. Esto provoca que en cada CCAA se incluyan distintas patologías y se utilicen distintas técnicas para el análisis de las muestras de sangre. Para evitar esta situación, se han establecido un mínimo de siete enfermedades que deben incluirse en los programas de cribado de todas las CCAA. A pesar de esta medida, sigue habiendo desigualdades entre los recién nacidos que se deben simplemente a su lugar de nacimiento. Para evitar esta situación resulta necesaria la creación de un programa de cribado neonatal único en España.Departamento de EnfermeríaGrado en Enfermerí

Atmosphere above a large solar pore

A large solar pore with a granular light bridge was observed on October 15, 2008 with the IBIS spectrometer at the Dunn Solar Telescope and a 69-min long time series of spectral scans in the lines Ca II 854.2 nm and Fe I 617.3 nm was obtained. The intensity and Doppler signals in the Ca II line were separated. This line samples the middle chromosphere in the core and the middle photosphere in the wings. Although no indication of a penumbra is seen in the photosphere, an extended filamentary structure, both in intensity and Doppler signals, is observed in the Ca II line core. An analysis of morphological and dynamical properties of the structure shows a close similarity to a superpenumbra of a sunspot with developed penumbra. A special attention is paid to the light bridge, which is the brightest feature in the pore seen in the Ca II line centre and shows an enhanced power of chromospheric oscillations at 3-5 mHz. Although the acoustic power flux in the light bridge is five times higher than in the "quiet" chromosphere, it cannot explain the observed brightness.Comment: 6 pages, 3 figures, accepted in Journal of Physics: Conference Serie

Imaging Spectropolarimetry with IBIS: Evolution of Bright Points in the Quiet Sun

We present the results from first spectropolarimetric observations of the solar photosphere acquired at the Dunn Solar Telescope with the Interferometric Bidimensional Spectrometer. Full Stokes profiles were measured in the Fe I 630.15 nm and Fe I 630.25 nm lines with high spatial and spectral resolutions for 53 minutes, with a Stokes V noise of 0.003 the continuum intensity level. The dataset allows us to study the evolution of several magnetic features associated with G-band bright points in the quiet Sun. Here we focus on the analysis of three distinct processes, namely the coalescence, fragmentation and cancellation of G-band bright points. Our analysis is based on a SIR inversion of the Stokes I and V profiles of both Fe I lines. The high spatial resolution of the G-band images combined with the inversion results helps to interpret the undergoing physical processes. The appearance (dissolution) of high-contrast G-band bright points is found to be related to the local increase (decrease) of the magnetic filling factor, without appreciable changes in the field strength. The cancellation of opposite-polarity bright points can be the signature of either magnetic reconnection or the emergence/submergence of magnetic loops.Comment: 4 pages, 5 figures, accepted for publication in ApJ Letter