2,178 research outputs found
The Open Data Movement: Young Activists between Data Disclosure and Digital Reputation
Young citizens show an increasing interest for direct democracy tools and for the building of a new relationship with public administration through the use of digital platforms. The Open Data issue is part of this transformation. The paper analyzes the Open Data issue from the perspective of a spontaneous and informal group of digital activists with the aim of promoting data disclosure. The study is focused mainly on the case of a specific local movement, named Open Data Sicilia (ODS), combining traditional ethnographic observation with an ethnographic approach. The aim of the study is to detect the social pro-file of the Open Data movement activists, understanding how is it organized their network, what are the common purposes and solidarity models embodied by this type of movement, what are the resources mo-bilized and their strategies between on-line and off-line. The ODS case appears interesting for its evolu-tion, its strategy and organizational structure: an elitist and technocratic movement that aspires to a broad constituency. It is an expressive or a reformist movement, rather than an anti-system actor, with features that are similar to a lobby. The case study also shows all the typical characteristics of digital activism, with its fluid boundaries between ethical inspiration of civic engagement and individual interest
Inducing a probability distribution in Stochastic Multicriteria Acceptability Analysis
In multiple criteria decision aiding, very often the alternatives are
compared by means of a value function compatible with the preferences expressed
by the Decision Maker. The problem is that, in general, there is a plurality of
compatible value functions, and providing a final recommendation on the problem
at hand considering only one of them could be considered arbitrary to some
extent. For such a reason, Stochastic Multicriteria Acceptability Analysis
gives information in statistical terms by taking into account a sample of
models compatible with the provided preferences. These statistics are given
assuming the existence of a probability distribution in the space of value
functions being defined a priori. In this paper, we propose some methods aiming
to build a probability distribution on the space of value functions considering
the preference information given by the Decision Maker. To prove the goodness
of our proposal we performed an extensive set of simulations. Moreover, a
sensitivity analysis on the variables of our procedure has been done as well
End to end numerical simulations of the MAORY multiconjugate adaptive optics system
MAORY is the adaptive optics module of the E-ELT that will feed the MICADO
imaging camera through a gravity invariant exit port. MAORY has been foreseen
to implement MCAO correction through three high order deformable mirrors driven
by the reference signals of six Laser Guide Stars (LGSs) feeding as many
Shack-Hartmann Wavefront Sensors. A three Natural Guide Stars (NGSs) system
will provide the low order correction. We develop a code for the end-to-end
simulation of the MAORY adaptive optics (AO) system in order to obtain
high-delity modeling of the system performance. It is based on the IDL language
and makes extensively uses of the GPUs. Here we present the architecture of the
simulation tool and its achieved and expected performance.Comment: 8 pages, 4 figures, presented at SPIE Astronomical Telescopes +
Instrumentation 2014 in Montr\'eal, Quebec, Canada, with number 9148-25
On the use of asymmetric PSF on NIR images of crowded stellar fields
We present data collected using the camera PISCES coupled with the Firt Light
Adaptive Optics (FLAO) mounted at the Large Binocular Telescope (LBT). The
images were collected using two natural guide stars with an apparent magnitude
of R<13 mag. During these observations the seeing was on average ~0.9". The AO
performed very well: the images display a mean FWHM of 0.05 arcsec and of 0.06
arcsec in the J- and in the Ks-band, respectively. The Strehl ratio on the
quoted images reaches 13-30% (J) and 50-65% (Ks), in the off and in the central
pointings respectively. On the basis of this sample we have reached a J-band
limiting magnitude of ~22.5 mag and the deepest Ks-band limiting magnitude ever
obtained in a crowded stellar field: Ks~23 mag.
J-band images display a complex change in the shape of the PSF when moving at
larger radial distances from the natural guide star. In particular, the stellar
images become more elongated in approaching the corners of the J-band images
whereas the Ks-band images are more uniform. We discuss in detail the strategy
used to perform accurate and deep photometry in these very challenging images.
In particular we will focus our attention on the use of an updated version of
ROMAFOT based on asymmetric and analytical Point Spread Functions.
The quality of the photometry allowed us to properly identify a feature that
clearly shows up in NIR bands: the main sequence knee (MSK). The MSK is
independent of the evolutionary age, therefore the difference in magnitude with
the canonical clock to constrain the cluster age, the main sequence turn off
(MSTO), provides an estimate of the absolute age of the cluster. The key
advantage of this new approach is that the error decreases by a factor of two
when compared with the classical one. Combining ground-based Ks with space
F606W photometry, we estimate the absolute age of M15 to be 13.70+-0.80 Gyr.Comment: 15 pages, 7 figures, presented at the SPIE conference 201
Idiopathic Calcium Nephrolithiasis: A Review of Pathogenic Mechanisms in the Light of Genetic Studies
Background: Calcium nephrolithiasis is a multifactorial disease with a polygenic milieu. Association studies identified genetic polymorphisms potentially implicated in the pathogenesis of calcium nephrolithiasis. The present article reviews the mechanisms of calcium stone formation and the potential contribution of gene polymorphisms to lithogenic mechanisms. Summary: Endoscopy observations suggested that precipitation of calcium-oxalate on the Randall's plaque at the papilla surface may cause idiopathic calcium-oxalate stones. The Randall's plaque is a hydroxyapatite deposit in the interstitium of the kidney medulla, which resembles a soft tissue calcification. Conversely, calcium-phosphate stones may develop from crystalline deposits located at the tip of the Bellini duct. Polymorphisms of eleven genes have been associated with stones in genome-wide association studies and replicated candidate-gene association studies: VDR, SLC34A1, SLC34A4, CLDN14, and CaSR genes coding for proteins regulating tubular phosphate and calcium reabsorption; CaSR, MGP, OPN, PLAU, and UMOD genes coding for proteins preventing calcium salt precipitation; AQP1 gene coding for a water channel in the proximal tubule. The renal activity of the last gene, DGKH, is unknown. Polymorphisms in these genes may predispose to calcium-oxalate and -phosphate stones by increasing the risk of calcium-phosphate precipitation in the tubular fluid. Key Messages: Genetic findings suggest that tubular fluid supersaturation with respect to calcium and phosphate predisposes to calcium-oxalate stones by triggering cellular mechanisms that lead to the Randall's plaque formation. © 2014 S. Karger AG, Base
Update on the genetics of nephrolithiasis
Genetic studies of calcium kidney stones evidenced the possible involvement of calcium-sensing receptor gene, vitamin D receptor gene and bicarbonate-sensitive adenylate cyclase gene, but it is uncertain which specific polymorphisms could be responsible. Thus, further studies are required to better assess the involvement of these or other genes and the interactions between different genes and between genes and environment.
In addition to research in humans, the study of different strains of knock-out mice let us include the gene of phosphate reabsorption carrier NPT2, caveolin-1, protein NHERF-1, osteopontin and Tamm-Horsfall protein among the possible determinants. Further steps in the knowledge of calcium stone causes may be done using the instruments that the modern biotechnology and bioinformatics have made available to the researchers
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