1,312 research outputs found
A generalization of the "probléme des rencontres"
In this paper, we study a generalization of the classical \emph{probl\'eme des rencontres} (\emph{problem of coincidences}),
consisting in the enumeration of all permutations \pi \in \SS_n with fixed points,
and, in particular, in the enumeration of all permutations \pi \in \SS_n with no fixed points (derangements).
Specifically, we study this problem for the permutations of the
symbols , , \ldots, , , , \ldots, ,
where for every .
In this way, we obtain a generalization of the derangement numbers,
the rencontres numbers and the rencontres polynomials.
For these numbers and polynomials, we obtain the exponential generating series, some recurrences and representations,
and several combinatorial identities. Moreover, we obtain the expectation and the variance
of the number of fixed points in a random permutation of the considered kind.
Finally, we obtain some asymptotic formulas
for the generalized rencontres numbers and the generalized derangement numbers
USE OF SATELLITE SAR DATA FOR SEISMIC RISK MANAGEMENT: RESULTS FROM THE PRE-OPERATIONAL ASI-SIGRIS PROJECT
In the framework of the National Space Programme, and of the European GMES Programme, the Italian Space Agency (ASI) has funded several pilot projects aimed at demonstrating the full potential of Earth Observation data in the monitoring and management of natural hazards.
The SIGRIS (Earth Observation System for Seismic Risk Management) pilot project has developed a hardware/software infrastructure for the generation of decision support products for the seismic risk management.
A pre-operational demonstration of the SIGRIS system is being carried out since June 2009 and various products to be used by civil protection authorities in either the Knowledge & Prevention or Crisis Management phases of seismic risk management, have been generated.
SIGRIS products to support the Knowledge & Prevention activities are based on the integration of satellite and ground-based observations to constrain analytical and numerical models of the tectonic strain accumulation and of its long-term effects on the earthquake source. They include crustal deformation maps from time series DInSAR and GPS, and fault models to improve the seismic hazard assessment.
SIGRIS products for the Crisis Management phase are instead focused on the quick generation of value added information needed to devise damage or event scenarios, and typically consist of damage assessment maps from high resolution optical and SAR data, co-seismic displacements maps from DInSAR analysis, seismic source models, maps of earthquake-induced environmental effects (landslides, surface fractures, ecc.). For these products a near-real time capability is required and new constellations, as COSMO-SkyMed , can now provide the necessary temporal revisit to fulfil this need. The SIGRIS system is also depending on other SAR satellites to ensure a faster and better coverage of the disaster areas: ENVISAT, Radarsat, TerraSar X, ALOS.
We will present examples of the SIGRIS decision support products based on the integration of Earth Observation and ground data and discuss important issues related to disaster applications, as EO data programming, fast data access, data archival
A Quantitative Functional Central Limit Theorem for Shallow Neural Networks
We prove a Quantitative Functional Central Limit Theorem for one-hidden-layer
neural networks with generic activation function. The rates of convergence that
we establish depend heavily on the smoothness of the activation function, and
they range from logarithmic in non-differentiable cases such as the Relu to
for very regular activations. Our main tools are functional versions
of the Stein-Malliavin approach; in particular, we exploit heavily a
quantitative functional central limit theorem which has been recently
established by Bourguin and Campese (2020)
EvAAL: Evaluating AAL Systems through Competitive Benchmarking
Owing to the complexity of Ambient Assisted Living (AAL) systems and platforms, the evaluation of AAL solutions is a complex task that will challenge researchers for years to come. However, the analysis and comparison of proposed solutions is paramount to enable us to assess research results in this area. We have thus organized an international contest called EvAAL: Evaluating AAL Systems through Competitive Benchmarking. Its aims are to raise interest within the research and developer communities in the multidisciplinary research fields enabling AAL, and to create benchmarks for the evaluation and comparison of AAL systems
The galectin-3/RAGE dyad modulates vascular osteogenesis in atherosclerosis
Vascular calcification correlates with inflammation and plaque instability in a dual manner, depending on the spotty/granular (micro) or sheet-like/lamellated (macro) pattern of calcification. Modified lipoproteins trigger both inflammation and calcification via receptors for advanced lipoxidation/glycation endproducts (ALEs/AGEs). This study compared the roles of galectin-3 and receptor for AGEs (RAGE), two ALEs/AGEs-receptors with diverging effects on inflammation and bone metabolism, in the process of vascular calcification. We evaluated galectin-3 and RAGE expression/localization in 62 human carotid plaques and its relation to calcification pattern, plaque phenotype, and markers of inflammation and vascular osteogenesis; and the effect of galectin-3 ablation and/or exposure to an ALE/AGE on vascular smooth muscle cell (VSMC) osteogenic differentiation. While RAGE co-localized with inflammatory cells in unstable regions with microcalcification, galectin-3 was expressed also by VSMCs, especially in macrocalcified areas, where it co-localized with alkaline phosphatase. Expression of galectin-3 and osteogenic markers was higher in macrocalcified plaques, whereas the opposite occurred for RAGE and inflammatory markers. Galectin-3-deficient VSMCs exhibited defective osteogenic differentiation, as shown by altered expression of osteogenic transcription factors and proteins, blunted activation of pro-osteoblastogenic Wnt/β-catenin signalling and proliferation, enhanced apoptosis, and disorganized mineralization. These abnormalities were associated with RAGE up-regulation, but were only in part prevented by RAGE silencing, and were partially mimicked or exacerbated by treatment with an AGE/ALE. These data indicate a novel molecular mechanism by which galectin-3 and RAGE modulate in divergent ways, not only inflammation, but also vascular osteogenesis, by modulating Wnt/β-catenin signalling, and independently of ALEs/AGEs
TIMIT-TTS: a Text-to-Speech Dataset for Multimodal Synthetic Media Detection
With the rapid development of deep learning techniques, the generation and
counterfeiting of multimedia material are becoming increasingly straightforward
to perform. At the same time, sharing fake content on the web has become so
simple that malicious users can create unpleasant situations with minimal
effort. Also, forged media are getting more and more complex, with manipulated
videos that are taking the scene over still images. The multimedia forensic
community has addressed the possible threats that this situation could imply by
developing detectors that verify the authenticity of multimedia objects.
However, the vast majority of these tools only analyze one modality at a time.
This was not a problem as long as still images were considered the most widely
edited media, but now, since manipulated videos are becoming customary,
performing monomodal analyses could be reductive. Nonetheless, there is a lack
in the literature regarding multimodal detectors, mainly due to the scarsity of
datasets containing forged multimodal data to train and test the designed
algorithms. In this paper we focus on the generation of an audio-visual
deepfake dataset. First, we present a general pipeline for synthesizing speech
deepfake content from a given real or fake video, facilitating the creation of
counterfeit multimodal material. The proposed method uses Text-to-Speech (TTS)
and Dynamic Time Warping techniques to achieve realistic speech tracks. Then,
we use the pipeline to generate and release TIMIT-TTS, a synthetic speech
dataset containing the most cutting-edge methods in the TTS field. This can be
used as a standalone audio dataset, or combined with other state-of-the-art
sets to perform multimodal research. Finally, we present numerous experiments
to benchmark the proposed dataset in both mono and multimodal conditions,
showing the need for multimodal forensic detectors and more suitable data
Ground Deformation Imagery of the May Sichuan Earthquake
The magnitude Mw = 7.8 earthquake that struck China's Sichuan region on 12 May 2008 (Figure 1a) has been imaged by the Italian Space Agency's (ASI) Constellation of Small Satellites for the Mediterranean Basin Observation (COSMO)‐SkyMed radar Earth observation satellites. Five images were available—two preseismic spotlight mode images and three strip‐map mode images, two of which are preseismic and one of which is postseismic. We used two strip‐map images (acquired 1 month prior to and 3 days after the earthquake) to generate the first ever X‐band (i.e., microwave frequency domain, corresponding to about 3‐ centi meter wavelength) coseismic interferogram, which clearly shows part of the strong ground deformation caused by the fault dislocation. We also performed a change detection analysis of the same data that highlighted several changes in the radar response, presumably due to strong seismic damage, as far as 80 kilo meters away from the epicenter
Analyses of TIMS and AVIRIS data, integrated with field and laboratory spectra, for lithological and mineralogical interpretation of Vulcano Island, Italy
Vulcano Island is part of the Eolian archipelago, located about 25 km from the northeast coast of Sicily. The archipelago comprises seven major volcanic islands, two of which are active volcanoes (Vulcano and Stromboli). Vulcano covers an area of about 50 square km, and is about 10 km long. Explosive volcanic activity has predominated in the geological evolution of Vulcano Island, and there is no evidence that this pattern has ceased. Rather, the current situation is one of unrest, so a strict regimen of continuous geophysical and geochemical monitoring has been undertaken over the last decade. Though the year-round population of Vulcano is small (under 1000), during the summer the island becomes a very popular resort, and has thousands of additional tourists at any time throughout the high season, thus substantially increasing the number of people potentially at risk from an explosive eruption or other hazards such as noxious gas emissions (e.g., CO2, H2S, SO2). During the past ten years, remote sensing data have been repetitively acquired with optical and microwave airborne sensors. The present work shows the preliminary results of a study based on the integration of various remote sensing data sets with field spectroscopy, and other laboratory analyses, for the geological and geomorphological mapping of the island. It is hoped that such work will also usefully contribute to the evaluation of the volcanic hazard potential of the islands as well as to the evaluation of the status of its current activity
Contribution of the EVER-EST project to the community of the Geohazard Supersites initiative
The EVER-EST project (European Virtual Environment for Research - Earth Science Themes: a solution) is
a H2020 project (2015-2018) aimed at the creation of a Virtual Research Environment (VRE) focused on the
requirements of the Earth Science community. The VRE is intended to enhance the ability to collaborate, interoperate and share knowledge and experience between all relevant stakeholders, including researchers, monitoring teams and civil protection agencies. Among the innovations of the project is the exploitation of the “Research Object” concept.PublishedVIenna,Austria1VV. Altr
Peripheral blood regulatory T cell measurements correlate with serum vitamin D level in patients with psoriasis
OBJECTIVE:Vitamin D is the precursor of a hormone (1,25-dihydroxyvitamin D3), which has many biological effects in the skin. The immune modulator properties of vitamin D are mediated in part through effects on regulatory T cells (T-reg). Currently, in psoriasis, the relationship between vitamin D and T-reg has not well elucidated. We assess whether vitamin D status is correlated with circulating T-reg in patients affected by psoriasis and if there is a correlation with the severity of the disease evaluated with Psoriasis Area Severity Index (PASI) score.
PATIENTS AND METHODS:For each patient we have analyzed, PASI-score, serum levels vitamin D and regulatory T cell percentages. Spearmen's coefficient was used between serum vitamin D levels and the predictors. Subsequently, the independent predictive factors were assessed by Multiple Regression.
RESULTS:A total of 26 patients were included in our analysis. Using no parametric Spearman's Coefficient test between serum levels of vitamin D and the single variables, we found an association with T-reg population (p < 0.001) and with PASI-score (p = 0.04).
CONCLUSIONS:While vitamin D treatment induces a cytokine profile known to favor the differentiation of T cells with suppressive activity, at the same time, several studies showed how vitamin D can prime for tolerogenic dendritic cells able to favor the differentiation of Treg from T naïve cells. Low levels of vitamin-D may decrease the number of circulatory T-reg, disrupting the immunological homeostasis in psoriatic patients and encouraging the inflammatory activity
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