7,290 research outputs found
MAGDA: A Mobile Agent based Grid Architecture
Mobile agents mean both a technology
and a programming paradigm. They allow for a
flexible approach which can alleviate a number
of issues present in distributed and Grid-based
systems, by means of features such as migration,
cloning, messaging and other provided mechanisms.
In this paper we describe an architecture
(MAGDA – Mobile Agent based Grid Architecture)
we have designed and we are currently
developing to support programming and execution
of mobile agent based application upon Grid
systems
Spectral Graph Convolutions for Population-based Disease Prediction
Exploiting the wealth of imaging and non-imaging information for disease
prediction tasks requires models capable of representing, at the same time,
individual features as well as data associations between subjects from
potentially large populations. Graphs provide a natural framework for such
tasks, yet previous graph-based approaches focus on pairwise similarities
without modelling the subjects' individual characteristics and features. On the
other hand, relying solely on subject-specific imaging feature vectors fails to
model the interaction and similarity between subjects, which can reduce
performance. In this paper, we introduce the novel concept of Graph
Convolutional Networks (GCN) for brain analysis in populations, combining
imaging and non-imaging data. We represent populations as a sparse graph where
its vertices are associated with image-based feature vectors and the edges
encode phenotypic information. This structure was used to train a GCN model on
partially labelled graphs, aiming to infer the classes of unlabelled nodes from
the node features and pairwise associations between subjects. We demonstrate
the potential of the method on the challenging ADNI and ABIDE databases, as a
proof of concept of the benefit from integrating contextual information in
classification tasks. This has a clear impact on the quality of the
predictions, leading to 69.5% accuracy for ABIDE (outperforming the current
state of the art of 66.8%) and 77% for ADNI for prediction of MCI conversion,
significantly outperforming standard linear classifiers where only individual
features are considered.Comment: International Conference on Medical Image Computing and
Computer-Assisted Interventions (MICCAI) 201
Nanocrystals of poorly soluble drugs: Drug bioavailability and physicochemical stability
Many approaches have been developed over time to overcome the bioavailability limitations of poorly soluble drugs. With the advances in nanotechnology in recent decades, science and industry have been approaching this issue through the formulation of drugs as nanocrystals, which consist of “pure drugs and a minimum of surface active agents required for stabilization”. They are defined as “carrier-free submicron colloidal drug delivery systems with a mean particle size in the nanometer range, typically between 10–800 nm”. The primary importance of these nanoparticles was the reduction of particle size to nanoscale dimensions, with an increase in the particle surface area in contact with the dissolution medium, and thus in bioavailability. This approach has been proven successful, as demonstrated by the number of such drug products on the market. Nonetheless, despite the definition that indicates nanocrystals as a “carrier-free” system, surface active agents are necessary to prevent colloidal particles aggregation and thus improve stability. In addition, in more recent years, nanocrystal properties and technologies have attracted the interest of researchers as a means to obtain colloidal particles with modified biological properties, and thus their interest is now also addressed to modify the drug delivery and targeting. The present work provides an overview of the achievements in improving the bioavailability of poorly soluble drugs according to their administration route, describes the methods developed to overcome physicochemical and stability-related problems, and in particular reviews different stabilizers and surface agents that are able to modify the drug delivery and targeting
Continuous monitoring of hydrogen and carbon dioxide at Mt Etna
This study assessed the use of an H2 fuel cell as an H2-selective sensor for volcano monitoring. The resolution,
repeatability, and cross-sensitivity of the sensor were investigated and evaluated under known laboratory
conditions. A tailor-made device was developed and used for continuously monitoring H2 and CO2 at Mt Etna
throughout 2009 and 2010. The temporal variations of both parameters were strongly correlated with the
evolution of the volcanic activity during the monitoring period. In particular, the CO2 flux exhibited long-term
variations, while H2 exhibited pulses immediately before the explosive activity that occurred at Mt Etna during
2010
A HIERARCHICAL DISTRIBUTED SHARED MEMORY PARALLEL BRANCH & BOUND APPLICATION WITH PVM AND OPENMP FOR MULTIPROCESSOR CLUSTERS
Branch&Bound (B&B) is a technique widely used to solve combinatorial optimization
problems in physics and engineering science. In this paper we show how the combined use
of PVM and OpenMP libraries can be a promising approach to exploit the intrinsic parallel
nature of this class of application and to obtain efficient code for hybrid computational
architectures. We described how both the shared memory and the distributed memory programming
models can be applied to implement the same algorithm for the inter-nodes and
intra-node parallelization. Some experimental tests on a local area network (LAN) of workstations
are finally discussed
Near-field light emission from semiconductor macroatoms
We present a microscopic theoretical analysis of time and spatially resolved photoluminescence of naturally occurring quantum dots induced by monolayer fluctuations in the thickness of semiconductor quantum wells. In particular we
study the carrier dynamics and the emission properties of a semiconductor quantum dot under both continuous-wave and pulsed excitations resonant with the barrier energy levels. We show that collection-mode near-field optical microscopy allows the detection of light emission from excitonic dark states. We find that, at low temperature, the second (dark) energy level displays a carrier density significantly larger
than that of the lowest energy level. This behaviour is a consequence of carrier trapping due to the symmetry-induced suppression of radiative recombination
Costruire apprendimento e partecipazione a scuola: da studenti unteachables a comunitĂ di motivated learners
Education of the future is a central theme in many debates nowadays. This paper focuses on the question what knowledge and skills are most relevant to prepare students for a rapidly changing society and if schools are able to respond effectively to costant transformation driven by technological innovation. While the school systemis involved in a modification process that concerns its core contents, new “wired” generations of students from lower secondary education are labelled as difficult to teach or even “unteachables”, students who are losing interest in academic learning, who are not motivated or responsible for their learning processes. The contribution examines the activities of an ongoing Erasmus+ research project - Unteachables. Helping the new generations of school teachers turn increasingly unteachable young students into young Learnables -, which involves school students (aged 12-16), university master students, in-training teachers and university researchers from seven European countries, aimed at experimenting teacher training activities designed to involve students in creating communities of motivated learners. This paper, profiling unteachables students, highlights the need of innovative teaching methods that can enhance motivation and participation of students
Characterization of Strombolian events by using independent component analysis
We apply Independent Component Analysis (ICA) to seismic signals recorded at Stromboli volcano. Firstly, we show how ICA works considering synthetic signals, which are generated by dynamical systems. We prove that Strombolian signals, both tremor and explosions, in the high frequency band (>0.5 Hz), are similar in time domain. This seems to give some insights to the organ pipe model generation for the source of these events. Moreover, we are able to recognize in the tremor signals a low frequency component (<0.5 Hz), with a well defined peak corresponding to 30s
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