939 research outputs found
Towards an automatic system for monitoring of CN2 and wind speed profiles with GeMS
Wide Field Adaptive Optics (WFAO) systems represent the more sophisticated AO
systems available today at large telescopes. A critical aspect for these WFAO
systems in order to deliver an optimised performance is the knowledge of the
vertical spatiotemporal distribution of the CN2 and the wind speed. Previous
studies (Cortes et al., 2012) already proved the ability of GeMS (the Gemini
Multi-Conjugated AO system) in retrieving CN2 and wind vertical stratification
using the telemetry data. To assess the reliability of the GeMS wind speed
estimates a preliminary study (Neichel et al., 2014) compared wind speed
retrieved from GeMS with that obtained with the atmospherical model Meso-Nh on
a small sample of nights providing promising results. The latter technique is
very reliable for the wind speed vertical stratification. The model outputs
gave, indeed, an excellent agreement with a large sample of radiosoundings (~
50) both in statistical terms and on individual flights (Masciadri et al.,
2013). Such a tool can therefore be used as a valuable reference in this
exercise of cross calibrating GeMS on-sky wind estimates with model
predictions. In this contribution we achieved a two-fold results: (1) we
extended analysis on a much richer statistical sample (~ 43 nights), we
confirmed the preliminary results and we found an even better correlation
between GeMS observations and the atmospherical model with basically no cases
of not-negligible uncertainties; (2) we evaluate the possibility to use, as an
input for GeMS, the Meso-Nh estimates of the wind speed stratification in an
operational configuration. Under this configuration these estimates can be
provided many hours in advanced with respect to the observations and with a
very high temporal frequency (order of 2 minutes or less).Comment: 12 pages, 7 figures, Proc. SPIE 9909 "Adaptive Optics Systems V",
99093B, 201
Towards an automatic wind speed and direction profiler for Wide Field AO systems
Wide Field Adaptive Optics (WFAO) systems are among the most sophisticated AO
systems available today on large telescopes. The knowledge of the vertical
spatio-temporal distribution of the wind speed (WS) and direction (WD) are
fundamental to optimize the performance of such systems. Previous studies
already proved that the Gemini Multi-Conjugated AO system (GeMS) is able to
retrieve measurements of the WS and WD stratification using the SLODAR
technique and to store measurements in the telemetry data. In order to assess
the reliability of these estimates and of the SLODAR technique applied to such
a kind of complex AO systems, in this study we compared WS and WD retrieved
from GeMS with those obtained with the atmospherical model Meso-Nh on a rich
statistical sample of nights. It has been previously proved that, the latter
technique, provided an excellent agreement with a large sample of
radiosoundings both, in statistical terms and on individual flights. It can be
considered, therefore, as an independent reference. The excellent agreement
between GeMS measurements and the model that we find in this study, proves the
robustness of the SLODAR approach. To by-pass the complex procedures necessary
to achieve automatic measurements of the wind with GeMS, we propose a simple
automatic method to monitor nightly WS and WD using the Meso-Nh model
estimates. Such a method can be applied to whatever present or new generation
facilities supported by WFAO systems. The interest of this study is, therefore,
well beyond the optimization of GeMS performance.Comment: 9 figures, 2 tables, MNRAS accepte
Fostering computational thinking skills with a tangible blocks programming environment
Computational Thinking has recently returned into the limelight as an essential skill to have for both the general public and disciplines outside Computer Science. It encapsulates those thinking skills integral to solving complex problems using a computer, thus widely applicable in our technological society. Several public initiatives such as the Hour of Code successfully introduced it to millions of people of different ages and backgrounds, mostly using Blocks Programming Environments like Scratch that lower the barriers of programming and facilitate learning. In this paper we present our arguments for fostering Computational Thinking skills using a Blocks Programming Environment augmented with a Tangible User Interface, namely by exploiting objects whose interactions with the physical environment are mapped to digital actions performed on the system. Our demonstration includes a working prototype implementing our Tangible Blocks Programming Environment called TAPAS
Characterizing dynamics with covariant Lyapunov vectors
A general method to determine covariant Lyapunov vectors in both discrete-
and continuous-time dynamical systems is introduced. This allows to address
fundamental questions such as the degree of hyperbolicity, which can be
quantified in terms of the transversality of these intrinsic vectors. For
spatially extended systems, the covariant Lyapunov vectors have localization
properties and spatial Fourier spectra qualitatively different from those
composing the orthonormalized basis obtained in the standard procedure used to
calculate the Lyapunov exponents.Comment: 4 pages, 3 figures, submitted to Physical Review letter
Tackling Prejudice and Discrimination Towards Families with Same-Sex Parents: An Exploratory Study in Italy
Though studies have shown that the sexual orientation of parents does not influence their parenting skills or the well-being of their children, prejudice against same-sex families is still very widespread. Research has not sufficiently explored the ways in which parents tackle this prejudice. Using qualitative methodologies, in particular textual analyses, this study has analysed the discourse used by same-sex families to handle the prejudices that they face. The results highlighted that conflicts, which may even be ideological in nature, are sometimes created between traditional families and “atypical” families. These often result in estrangement and isolation from their own family and the communities to which they belong, in turn damaging the growth of the children involved. Furthermore, means for moving beyond conflict, sharing experiences and effectively tackling prejudices are also discussed
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